Changchun, China
Changchun, China

Northeast Normal University is one of the six national universities in the People's Republic of China, located in Changchun, Jilin. The University was ranked No.37 in the comprehensive ranking of universities in China in 2013. Wikipedia.

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Jiao Y.-Q.,Heilongjiang University | Li M.-T.,Northeast Normal University | Qin C.,Northeast Normal University | Su Z.-M.,Northeast Normal University
CrystEngComm | Year: 2017

The first mixed-valence nickel-supported polyoxometalate-based metal-organic framework, (H2mim)[NiIII(Hmim)4][SiW11NiIIO37(OH)2(Hmim)]·3H2O (1) (Hmim = 2-methylimidazole), has been synthesized using a steam-assisted conversion method, and is constructed from noncovalent interactions (hydrogen bonds and π⋯π stacking interactions). 1 has a repeating honeycomb-shaped internal structure with one-dimensional channels along the direction of the c axis, where the diameter of the aperture is as large as 18.83 Å. Furthermore, the stability and the optical band gaps are investigated. © The Royal Society of Chemistry.

Yuan H.,Northeast Normal University | Zhang J.,Northeast Normal University
Journal of Computational Chemistry | Year: 2017

DFT calculations were conducted to pursue deeper understandings on the mechanism and the explicit role of trace water in the DBU-catalyzed β-amination of NBS to chalcone. Being different from previously proposed by Liang et al., a cooperative participation of both DBU and water is noticed in the preferred mechanism. The preferential mechanistic scenario assisted by water undergoes three major steps: the formation of succinimide and HBrO, concerted nucleophilic addition and H-shift, and keto-enol tautomerization. Moreover, we found that DBU-HBrO is unnecessary in the third step and three-water-cluster assisted keto-enol tautomerization is the most advantageous case. It is further noted that the catalytic position of the third water molecule and the proton shift orientation to some extent affect step 3 via O···HO and OH···π interactions, which is confirmed by AIM analysis. The computational results suggest that water molecules play pivotal roles as reactant, catalyst, and stabilizer to promote the reaction of chalcone and NBS. The origin of the more stable transition state structure in the rate-determining step of DBU-water catalyzed mechanism is ascribed to noncovalent interactions, halogen bond, and electrostatic interactions than DBU only ones. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Diao H.-A.,Northeast Normal University | Yan H.,Northeast Normal University | Chu E.K.-W.,Monash University
International Journal of Computer Mathematics | Year: 2017

In this paper, we consider the perturbation analysis for ⋆-Sylvester equations. Based on the small-sample condition estimation (SCE) technique, we devise algorithms to estimate normwise, mixed and componentwise condition numbers for ⋆-Sylvester equations. We also define a componentwise backward error with a sharp and easily computable bound. Numerical examples illustrate that our algorithm for componentwise perturbations produces reliable estimates, and the new derived computable bound for the componentwise backward error is sharp and reliable for well-conditioned and moderate ill-conditioned ⋆-Sylvester equations under large or small perturbations. © 2017 Informa UK Limited, trading as Taylor & Francis Group

Yuan G.,Northeast Normal University
Inverse Problems | Year: 2017

In this paper, we solve two kinds of inverse problems in determination of the initial data for stochastic parabolic equations. One is determination of the initial data by lateral boundary observation on arbitrary portion of the boundary, the second one is determination of the initial data by internal observation in a subregion inside the domain. We obtain conditional stability for the two kinds of inverse problems. To prove the results, we estimate the initial data by a terminal observation near the initial time, then we estimate this terminal observation by lateral boundary observation on arbitrary portion of the boundary or internal observation in a subregion inside the domain. To achieve those goals, we derive several new Carleman estimates for stochastic parabolic equations in this paper. © 2017 IOP Publishing Ltd.

Li X.,Northeast Normal University | Ma S.,Northeast Normal University | Hu J.,College of Logistics
Applied Intelligence | Year: 2017

The differential evolution algorithm (DE) has been shown to be a very simple and effective evolutionary algorithm. Recently, DE has been successfully used for the numerical optimization. In this paper, first, based on the fitness value of each individual, the population is partitioned into three subpopulations with different size. Then, a dynamically adjusting method is used to change the three subpopulation group sizes based on the previous successful rate of different mutation strategies. Second, inspired by the “DE/current to pbest/1”, three mutation strategies including “DE/current to cbest/1”, “DE/current to rbest/1” and “DE/current to fbest/1” are proposed to take on the responsibility for either exploitation or exploration. Finally, a novel effective parameter adaptation method is designed to automatically tune the parameter F and CR in DE algorithm. In order to validate the effectiveness of MSDE, it is tested on ten benchmark functions chosen from literature. Compared with some evolution algorithms from literature, MSDE performs better in most of the benchmark problems. © 2017 Springer Science+Business Media New York

Wan C.,Northeast Normal University | Zhang L.,Northeast Normal University
Mobile Networks and Applications | Year: 2017

In the current work, appropriated regulate and manmade brainpower are joined in regulate engineering for Large Scale Systems (LSS). The point of this design is to give the overall arrangement and philosophy to achieve the ideal regulate in arranged appropriated situations where various conditions between sub-frameworks are found. Frequently these conditions or associations speak to regulate variables so the circulated regulate must be reliable for both subsystems and the ideal estimation of these variables needs to fulfil a shared objective. The point of the exploration portrayed in this paper is to abuse the alluring components of MPC in a disseminated usage consolidating learning strategies to play out the strategy in these variables in a helpful Multi Agent environment and concluded a Multi-Agent framework (MAS-MPC) to give pace, versatility, and with the computational exertion lessening. This methodology depends on strategic, participation and erudition. Aftereffects of the use of this design to a little portable system demonstrate that the subsequent directions of the recurrence of sign which is a regulate variable that can be adequate contrasted with the brought together arrangement. The application to a genuine system has been considered. © 2017 Springer Science+Business Media New York

Hu X.-L.,Changchun University of Science and Technology | Yang X.-X.,Changchun University of Science and Technology | He X.-Q.,Changchun University of Science and Technology | Su Z.-M.,Northeast Normal University
Inorganic Chemistry Communications | Year: 2017

Two novel Zn-based coordination polymer through employing of in-situ solvothermal techniques by using NO2-bdc (2-nitroterephthalic acid), HL1 = 1-(tetrazo-5-yl)-4-(triazo-1-yl)benzene, HL2 = 1-(tetrazo-5-yl)-4-(triazo-1-yl)benzene and Zn(NO3)2·6H2O to form [Zn2(HL1)2(NO2-bdc)]·0.5 (DMA)·CH3OH·H2O (1) and [Zn2(μ3-OH) (HL2)·(NO2-bdc)]·0.5 (DMA)·H2O (2). The structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric (TG) analyses. In Compound 1, each Zn ion bridges one NO2-bdc and two HL1 ligands to yield infinite 2D layers, furthermore the aromatic π –π interactions link the adjacent layers yielding a 3D supramolecular structure. In compound 2, the HL2 ligands link Zn ions to form a 2D Zn(HL) sheet firstly, and further connected by double NO2-bdc pillars resulting in bi-pillared-layer type 3D frameworks. Moreover, 1 and 2 are luminescent with blue emission (λem = 440 nm and λem = 417 nm) in the solid-state. The fluorescent nature of 1and 2 inspired us to explore its potential application as a sensor for the detection of nitro explosives. The result reveals that 1 and 2 could be applied as a fluorescence sensor for NB (nitrobenzene) and 1,3-DNB (1,3-dinitrobenzene) with sensitivity and selectivity. © 2017 Elsevier B.V.

Jia L.,Northeast Normal University | Dong L.,Northeast Normal University | Zhu L.,Northeast Normal University
Applied Materials Today | Year: 2017

The synthesis of graphene oxide through the chemical exfoliation of graphite by oxidative treatment always gives rise to a significant amount of polyaromatic byproducts, which are usually termed as oxidative carbonaceous debris. The carbonaceous debris is strongly adsorbed on the surface of graphene oxide, which inevitably affects its physical and chemical properties. Herein, we investigate the influence of the adsorbed carbonaceous debris on the stripping analysis of cadmium at graphene oxide electrode. Voltammetric responses and analytical performances have been achieved and systematically compared in connection with the anodic stripping of cadmium performed at the graphene oxide electrodes in the presence and absence of the carbonaceous debris. The results suggested that the adsorption of the carbonaceous debris dramatically restricted the deposition of cadmium metal and lowered the stripping analytical performances of cadmium ions. © 2017 Elsevier Ltd

Li Y.-J.,Northeast Normal University | Yan N.,Northeast Normal University | Liu C.-H.,Northeast Normal University | Yu Y.,Northeast Normal University | Zhao Y.-L.,Northeast Normal University
Organic Letters | Year: 2017

A new strategy for direct and highly efficient synthesis of 2,3′-bisindolin-3-ones has been developed via a gold/copper-co-catalyzed tandem reactions of 2-alkynylanilines using TBHP as the terminal oxidant and oxygen-atom source. The single-step process involves a novel tandem intermolecular nucleophilic addition, intramolecular cyclization/oxidative cross-dehydrogenative coupling where up to four new bonds and two indole rings were created simultaneously in one-pot manner. The reaction features a broad substrate scope, good functional group tolerance, and high atom-economy. © 2017 American Chemical Society.

Zhang L.,Northeast Normal University | Liu X.,Northeast Normal University | Wang Y.,Northeast Normal University | Xing S.,Northeast Normal University
Journal of Alloys and Compounds | Year: 2017

Eccentric encapsulation of silver by polypyrrole was realized via the direct redox reaction between AgNO3 and pyrrole in the presence of sodium dodecyl sulfate. A facile method based on the relative amount of the Ag embedded in the normalized PPy sphere was developed and utilized to compare the interface tension between Ag, PPy and the solution. Via the aid of the embedding ratio, the formation of the eccentric silver@polypyrrole (Ag@PPy) was investigated by a temporal process and tuning the surfactant concentration and reaction temperature. Furthermore, such a unique nanostructure allowed the manipulation on the Ag end to achieve mushroom-like Au/Ag-PPy via the galvanic replacement reaction between Ag and HAuCl4, which was also dependent on the embedding ratio. After generating the above later nanostructure, much more active sites were available and much better catalytic activity was achieved taking the reduction of 4-nitrophenol by NaBH4 as an example reaction. © 2017 Elsevier B.V.

Gander M.J.,University of Geneva | Xu Y.,Northeast Normal University
Lecture Notes in Computational Science and Engineering | Year: 2017

Optimized Schwarz methods have attracted tremendous attention because of their excellent performance. For circular domain decompositions, Gander and Xu (SIAM J. Numer. Anal. 52(4): 1981-2004, 2014; Math. Comput., 2016b) showed that the interface curvature enters the optimized transmission condition and the corresponding convergence rate estimate. Since where the curvature is the only interface characteristic, how the curved interface affects the performance of the optimized Schwarz method is still not completely clear. In this short paper, we show, for an example of domain decomposition with parabolic interfaces, that not only the interface curvature, but also other characteristics of the interfaces will enter as well the optimized transmission parameter. We use numerical experiments to illustrate our theoretical findings. © Springer International Publishing AG 2017.

Shen H.Z.,Northeast Normal University | Li D.X.,Northeast Normal University | Yi X.X.,Northeast Normal University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2017

The Kubo formula is an equation that expresses the linear response of an observable due to a time-dependent perturbation. It has been extended from closed systems to open systems in recent years under the Markovian approximation, but is barely explored for open systems in non-Markovian regimes. In this paper, we derive a formula for the linear response of an open system to a time-independent external field. This response formula is available for both Markovian and non-Markovian dynamics depending on parameters in the spectral density of the environment. As an illustration of the theory, the Hall conductance of a two-band system subjected to environments is derived and discussed. With the tight-binding model, we point out the Hall conductance changes from Markovian to non-Markovian dynamics by modulating the spectral density of the environment. Our results suggest a way to the controlling of the system response, which has potential applications for quantum statistical mechanics and condensed matter physics. © 2017 American Physical Society.

Yin H.,Yanbian University | Geng Y.,Northeast Normal University | Sun G.-Y.,Yanbian University | Su Z.-M.,Yanbian University | Su Z.-M.,Northeast Normal University
Journal of Physical Chemistry C | Year: 2017

The intermolecular stacking and crystallization of perylene diimides (PDIs) has become research obstacles for small molecule acceptors (SMAs). For breaking molecular rigidity and planarity, it is an executable way to increase the distortion between two PDI units. A class of PDI dimers were designed via bridging different linkers in bay positions (1-1′ bridge) and headland positions (1-2′ bridge) to screen suitable acceptor materials for organic photovoltaic cells (OPVs). Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations were performed to investigate their electronic structures, open circuit voltage (VOC), driving forces (ΔEL-L), and some major parameters related to the short-circuit current density (JSC) such as absorption spectrum and carrier transport ability. Meanwhile, the intermolecular charge transfer (inter-CT) and charge recombination (inter-CR) rates were calculated for a further analysis on charge transfer properties at donor/acceptor (D/A) interface by employing the Marcus semiclassical model. The results manifest that the investigated 1-2′ bridged molecules possess low-lying LUMO energy levels, relatively bigger ΔEL-L, bathochromic-shifted absorption, as well as the strongest maximum absorption and more effective charge transport than 1-1′ bridged molecules. Surprisingly, compared with P3HT/(1-1′ bridged PDI dimers) interface, almost constant reorganization energy (λ), higher Gibbs free energy change of exciton dissociation (ΔGCT), and considerable inter-CT/inter-CR rates ratios (kinter-CT/kinter-CR) of P3HT/(1-2′ bridged PDI dimers) provides further evidence for that 1-2′ bridged PDI dimers as acceptors might perform higher efficiency in OPV device. Moreover, constructing NDT and DPPT as bridged linkers in PDI dimers as "push-pull" structures may rationally expect more favorable properties as acceptors in OPVs, which might provide theoretical guideline for the design and synthesis of new organic SMAs. (Chemical Equation Presented). © 2017 American Chemical Society.

Dong J.,Northeast Normal University | Xin S.,Northeast Normal University | Wang Y.,Northeast Normal University | Pan L.,Northeast Normal University | Liu Q.,Northeast Normal University
Chemical Communications | Year: 2017

A new three-component reaction, namely condensation-anti-Michael addition-aromatization, enabling the construction of benzylic compounds is disclosed. This reaction can not only act as an alternative approach to regioselective Csp2-H trifluoromethylation of arenes through an “aromatic to be” strategy, but also provides a simple, convenient, step-economic, and practical strategy for the in situ generation of electrophilic p-(trifluoromethyl)benzyl species under extremely mild conditions. © The Royal Society of Chemistry.

Jin G.,Jilin University | Wei H.,Jilin University | Cheng Z.,Jilin University | Sun H.,Northeast Normal University | Yang B.,Jilin University
Journal of Physical Chemistry C | Year: 2017

Due to their environmentally friendly ideology, aqueous-processed hybrid solar cells (HSCs) are favored for industrial production. However, relatively low device performance urges the progress in power conversion efficiency (PCE) for their further applications. In this work, the function of polymer and nanocrystal (NC) is studied by investigating three different device structures. The polymer (low hole mobility), which plays an important role even if the content is extremely low, is mainly responsible for enhancing the Voc and FF, while the NC (high hole mobility) is the principle part in light absorbing, carrier generating, and transporting. The intensive study of polymer and NC makes it possible to achieve high performance through adjusting the thickness of different active layers by using device structures of the cathode/electron transport layer (ETL)/NC/polymer:NC/hole transport layer (HTL)/anode. An efficient aqueous-processed HSC with PCE of 5.64% is obtained which presents the highest performance among polymer/NC HSCs to date. (Graph Presented). © 2017 American Chemical Society.

Liu Z.,Northeast Normal University | Li Q.,Northeast Normal University | Yang Y.,Northeast Normal University | Bi X.,Northeast Normal University | Bi X.,Nankai University
Chemical Communications | Year: 2017

Silver(i)-promoted carbene insertion into X-H (X = Si, Sn, and Ge) bonds has been realized by using unstable diazo compounds, which are generated in situ from N-nosylhydrazones as carbene precursors. The reaction tolerates a wide range of functional groups and delivers a number of valuable silicon-containing compounds in very high yields (up to 96%). Moreover, organostannanes and organogermanes were as well effectively obtained in very good yields under optimal conditions. © The Royal Society of Chemistry.

Li M.,Northeast Normal University | Liu T.,Northeast Normal University | Bo X.,Northeast Normal University | Zhou M.,Northeast Normal University | Guo L.,Northeast Normal University
Journal of Materials Chemistry A | Year: 2017

A novel three-dimensional (3D) hierarchically meso/macroporous flower-like architecture of ultra-thin N-doped carbon nanosheets (NCNS) with fine FeCo@NC core-shell units dispersed on their surfaces (denoted as FeCo@NC/NCNS) is reported as an efficient catalyst for two key electrode processes (i.e. the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER)) in the development of sustainable energy conversion systems. Upon optimization of the dosages of Fe/Co sources and calcination temperature, the optimal Fe0.5Co0.5@NC/NCNS-800 sample exhibits high activity with a potential of 1.5 V vs. reversible hydrogen electrode (RHE) to achieve a current density of 10 mA cm−2 for the OER in 1.0 M KOH, which even surpassed that of commercial RuO2. Moreover, as an HER electrocatalyst in 1.0 M KOH, Fe0.5Co0.5@NC/NCNS-800 just requires a low overpotential of 150 mV to achieve 10 mA cm−2 with an onset potential of −63 mV. All these results highlight the synergistic effects of the 3D macroporous channels of the flower-like architecture, 2D mesoporous CNSs, high specific surface area, fine FeCo@NC core-shell units, and various active centers for boosting the OER/HER catalytic activities, defining the Fe0.5Co0.5@NC/NCNS as one of the best non-precious metal-based carbonaceous electrocatalysts for oxygen/hydrogen-based electrocatalysis. More importantly, when Fe0.5Co0.5@NC/NCNS was used as positive and negative electrodes in a two-electrode system for overall water splitting, it just required a cell voltage of 1.60 V to achieve ∼10 mA cm−2, which opens a new possibility for the construction of novel water splitting devices. We also believe that our present synthetic strategy can encourage further research for the development of other 3D hierarchically meso/macroporous noble-metal-free catalysts for sensors, batteries, and various other renewable energy applications without any tedious steps or templates. © The Royal Society of Chemistry.

Huang X.,Northeast Normal University | Cong X.,Northeast Normal University | Mi P.,Northeast Normal University | Bi X.,Northeast Normal University | Bi X.,Nankai University
Chemical Communications | Year: 2017

A new silver-promoted [3+2] cycloaddition of azomethine ylides with isocyanides has been described. The methodology provides an efficient and modular approach to 1,2,4-trisubstituted imidazoles of vital bioactive molecules and atypical antipsychotics analogues. © The Royal Society of Chemistry.

Wang D.,Northeast Normal University | Duan H.,Northeast Normal University | Lu J.,Northeast Normal University | Lu C.,Northeast Normal University
Journal of Materials Chemistry A | Year: 2017

A novel strategy was developed to fabricate thermo-responsive copolymer functionalized reduced graphene oxide@Fe3O4@Au magnetic nanocomposites (Au NPs@GFDP) for highly efficient catalysis. Superparamagnetic Fe3O4 nanoparticles (NPs) on reduced graphene oxide (RGO@Fe3O4) were obtained via a one-pot chemical functionalization method. RGO@Fe3O4 was coated with dopamine (DA) to generate polydopamine (PDA) modified RGO@Fe3O4 (GFD) through a combination of mussel inspired chemistry of dopamine in a weakly alkaline aqueous solution. The thermo-responsive polymer of poly(N-isopropylacrylamide-co-2,3-epithiopropyl methacrylate) P(NIPAM-co-ETMA) (P) was synthesized via a reversible addition fragmentation chain transfer (RAFT) polymerization and was facilely grafted onto the surface of GFD through a Michael addition reaction. The final gold nanoparticle (Au NP) functionalized GFDP nanocomposites were obtained through in situ reduction of gold precursors in GFDP solution using the episulfide groups of P(NIPAM-co-ETMA) as a ligand. The Au NPs@GFDP nanocomposite exhibited excellent dispersibility and stability in aqueous solutions. More importantly, the obtained nanocomposite also displayed easy recyclability because of the existence of Fe3O4 NPs and a higher catalytic efficiency for the reduction of nitrophenols over the Au NPs@RGO@Fe3O4 and Au NPs@GO without polymer modification. Au NPs@GFDP modified with PNIPAM also exhibited excellent temperature-responsive behavior for the catalytic reduction of nitrophenol. Therefore, the strategy described in this work may be of great potential for various industrial catalytic applications. © The Royal Society of Chemistry.

He X.,Northeast Normal University | Li S.,Jilin Institute of Biology | Kaminskyj S.,University of Saskatchewan
International Journal of Molecular Sciences | Year: 2017

α-Glucan affects fungal cell–cell interactions and is important for the virulence of pathogenic fungi. Interfering with production of α-glucan could help to prevent fungal infection. In our previous study, we reported that an amylase-like protein, AmyD, could repress α-glucan accumulation in Aspergillus nidulans. However, the underlying molecular mechanism was not clear. Here, we examined the localization of AmyD and found it was a membrane-associated protein. We studied AmyD function in α-glucan degradation, as well as with other predicted amylase-like proteins and three annotated α-glucanases. AmyC and AmyE share a substantial sequence identity with AmyD, however, neither affects α-glucan synthesis. In contrast, AgnB and MutA (but not AgnE) are functional α-glucanases that also repress α-glucan accumulation. Nevertheless, the functions of AmyD and these glucanases were independent from each other. The dynamics of α-glucan accumulation showed different patterns between the AmyD overexpression strain and the α-glucanase overexpression strains, suggesting AmyD may not be involved in the α-glucan degradation process. These results suggest the function of AmyD is to directly suppress α-glucan synthesis, but not to facilitate its degradation. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.

Li P.,Purdue University | Yuan G.,Northeast Normal University
Journal of Mathematical Analysis and Applications | Year: 2017

Consider the one-dimensional stochastic Helmholtz equation where the source is assumed to be driven by the white noise. This paper concerns the stability analysis of the inverse random source problem which is to reconstruct the statistical properties of the source such as the mean and variance. Our results show that increasing stability can be obtained for the inverse problem by using suitable boundary data with multi-frequencies. © 2017 Elsevier Inc.

Jiang L.,Jilin Business and Technology College | Wang Y.,Northeast Normal University
ICIC Express Letters, Part B: Applications | Year: 2017

In order to handle the difficulties of complex tracking conditions in real tracking problems, this paper proposed a novel Adaboost based tracking algorithm. In the proposed method, visual tracking is resolved as a two-class classification problem between fore-ground (the target) and its background. And the classification is resolved by designing an adaptive classifier. In detail, an on-line updated Adaboost classifier is designed to overcome the limitation of single classifier in tracking accuracy and robustness. Specially, the problem of sample’s label is considered, and the confidence is assigned to each input sample as its class, so as to realize more accurate classification. In addition, multiple salient features are integrated to represent target’s appearance and provided to the classifier, so as to realize the robustness. The experimental results demonstrate the robustness and accuracy of the proposed Adaboost classifier in dealing with tracking problems. © 2017 ICIC International.

Lai Y.,Jilin University | Liu D.,Key Laboratory of Symbolic Computation | Yin M.,Northeast Normal University
Journal of Artificial Intelligence Research | Year: 2017

We identify two families of canonical knowledge compilation languages. Both families augment ROBDD with conjunctive decomposition bounded by an integer i ranging from 0 to ∞. In the former, the decomposition is finest and the decision respects a chain C of variables, while both the decomposition and decision of the latter respect a tree Τ of variables. In particular, these two families cover three existing languages ROBDD, ROBDD with as many implied literals as possible, and AND/OR BDD. We demonstrate that each language in the first family is complete, while each one in the second family is incomplete with expressivity that does not decrease with incremental i. We also demonstrate that the succinctness does not decrease from the i-th language in the second family to the i-th language in the first family, and then to the (i+1)-th language in the first family. For the operating effciency, on the one hand, we show that the two families of languages support a rich class of tractable logical operations, and particularly the tractability of each language in the second family is not less than that of ROBDD; and on the other hand, we introduce a new time effciency criterion called rapidity which re ects the idea that exponential operations may be preferable if the language can be exponentially more succinct, and we demonstrate that the rapidity of each operation does not decrease from the i-th language in the second family to the i-th language in the first family, and then to the (i + 1)-th language in the first family. Furthermore, we develop a compiler for the last language in the first family (i = ∞). Empirical results show that the compiler significantly advances the compiling effciency of canonical representations. In fact, its compiling effciency is comparable with that of the state-of-the-art compilers of non-canonical representations. We also provide a compiler for the i-th language in the first family by translating the last language in the first family into the i-th language (i < ∞). Empirical results show that we can sometimes use the ∞-th language instead of the last language without any obvious loss of space effciency. © 2017 AI Access Foundation.

Wang Y.,Northeast Normal University | Cai S.,CAS Institute of Software | Yin M.,Northeast Normal University
Journal of Artificial Intelligence Research | Year: 2017

The Minimum Weight Dominating Set (MWDS) problem is an important generalization of the Minimum Dominating Set (MDS) problem with extensive applications. This paper proposes a new local search algorithm for the MWDS problem, which is based on two new ideas. The first idea is a heuristic called two-level configuration checking (CC2), which is a new variant of a recent powerful configuration checking strategy (CC) for effectively avoiding the recent search paths. The second idea is a novel scoring function based on the frequency of being uncovered of vertices. Our algorithm is called CC2FS, according to the names of the two ideas. The experimental results show that, CC2FS performs much better than some state-of-the-art algorithms in terms of solution quality on a broad range of MWDS benchmarks. © 2017 AI Access Foundation.

Zhou Y.H.,Baicheng Normal College | Zhang S.S.,Northeast Normal University | Shen H.Z.,Northeast Normal University | Yi X.X.,Northeast Normal University
Optics Letters | Year: 2017

In analogy to electromagnetically induced transparency, optomechanically induced transparency was proposed recently in [Science 330, 1520 (2010)]. In this Letter, we demonstrate another form of induced transparency enabled by second-order nonlinearity. A practical application of the second-order nonlinearity induced transparency is to measure the second-order nonlinear coefficient. Our scheme might find applications in quantum optics and quantum information processing. © 2017 Optical Society of America.

Wu H.,Northeast Normal University | Liu H.-Y.,Northeast Normal University | Liu Y.-Y.,Northeast Normal University | Yang J.,Northeast Normal University | And 2 more authors.
Chemical Communications | Year: 2011

An unprecedented 2D → 3D metal-organic polyrotaxane framework, based on a new star-like tri(4-imidazolylphenyl)amine ligand, has been synthesized and characterized, which represents the first example of 2D → 3D polyrotaxane entangled in a parallel fashion. © 2011 The Royal Society of Chemistry.

Zhang Y.,Northeast Normal University | Zhou X.,Peking University | Zhang M.,Northeast Normal University | Zhang M.,Tianjin Normal University
Psychophysiology | Year: 2012

Recent studies propose that a mechanism termed "inhibitory tagging" acts upon the processing of the target at the attended location by temporarily blocking the stimulus-response mapping. Here we combined the cue-target paradigm with the Stroop task and measured event-related potential (ERP) responses to the color of a color word presented at the previously attended (cued) or unattended (uncued) location. We found that the conflict-related N450 effect emerged later and had a smaller size at the cued than the uncued location. The overall ERP responses to the target showed lower P1 and N1 amplitude at the cued than the uncued location. Although the P1/N1 effect may reflect deficient perceptual processing of the target, the delay of the N450 suggests that the link between perceptual processing and response activation is temporarily blocked at the previously attended location. © 2012 Society for Psychophysiological Research.

Wu H.,Northeast Normal University | Liu H.-Y.,Northeast Normal University | Yang J.,Northeast Normal University | Liu B.,Northeast Normal University | And 2 more authors.
Crystal Growth and Design | Year: 2011

Seven new coordination polymers, namely, [Cd(Tipa)(L1)2] •H2O (1), [Cd(Tipa)(L2)]•H2O (2), [Cd(Tipa)(L2)]•CH3OH•H2O (3), Cd(Tipa)(L3)(H2O) (4), [Mn(Tipa)(L2)]•H2O (5), [Ni2(Tipa)2(L4)(H2O)2] 2•Cl4•4H2O (6), and [Ni 2(Tipa)2(L5)(H2O)4]•(H 4L5)•0.5H2O (7), where HL1 = benzoic acid, H 2L2 = 5-NH2-1,3-benzenedicarboxylic acid, H2L3 = 2-(4-carboxybenzylamino)benzoic acid, H2L4 = 1,4- benzenedicarboxylic acid, H4L5 = 1,2,4,5-benzenetetracarboxylic acid, and Tipa = tri(4-imidazolylphenyl)amine, have been synthesized by varying the carboxylate anions and metal centers under hydrothermal conditions. Compound 1 shows a one-dimensional (1D) chain. Compounds 2 and 5 are isostructural and display (3,5)-connected (42•6)(42•6 7•8) topology. In the two compounds, the identical 2D networks entangle in highly rare parallel fashions to give fascinating 2D → 3D frameworks with polycatenation and polyrotaxane characters. Compound 3 displays a 2-fold interpenetrating 3D framework with (3,5)-connected (6 3)(65•85) topology. The structure of 4 is a 4-fold interpenetrating 3D (10,3)-b framework. 6 is an uncommon 4-fold interpenetrating 3D framework with (3,4)-connected (4•82) (4•85) topology. 7 exhibits an unprecedented 2D → 2D polyrotaxane layer with (3,4)-connected (42•6)(4 2•63•8) topology. The IR spectra, elemental analyses, and luminescent properties for the compounds were also investigated. © 2011 American Chemical Society.

Li H.,Soochow University of China | He X.,Soochow University of China | Kang Z.,Soochow University of China | Kang Z.,Northeast Normal University | And 5 more authors.
Angewandte Chemie - International Edition | Year: 2010

(Figure Presented) Size control: A one-step alkali metalassisted electrochemical method for the fabrication of carbon quantum dots (CQDs) with size-dependent photoluminescence is presented (see picture). Their upconversion luminescence may provide a way for the development of novel photocatalysts. © 2010 Wiley-VCH Verlag GmbH &. Co. KGaA, Weinheim.

Jin R.F.,Chifeng University | Chang Y.F.,Northeast Normal University
Physical Chemistry Chemical Physics | Year: 2015

A series of D-π-A star-shaped molecules with triphenylamine (TPA) as a core, 1,8-naphthalimide (NI) derivatives as end groups, and different p-bridges have been designed to explore their optical, electronic, and charge transport properties as organic solar cell (OSC) materials. The calculation results showed that the star-shaped molecules can lower the material band gap and extend the absorption spectrum towards longer wavelengths. The designed molecules own the longest wavelength of absorption spectra, oscillator strength, and absorption region values. Our results suggest that the designed molecules are expected to be promising candidates for OSC materials. Additionally, the molecules with ethyne, thiophene, benzo[c][1,2,5]thiadiazole (BTA), and 2,3-dihydrothieno[3,4-b][1,4]dioxine (DTD) as π-bridges and 4-pyridne, 4-aniline, and H in NI fragments have better hole- and electron transporting balance and can act as nice ambipolar materials. The values of hole mobility of molecules with ethyne as a π-bridge and NI as an end group for Pna21 and P21/c are 5.30 × 10-3 and 1.27 × 10-2 cm2 V-1 s-1, respectively. On the basis of the investigated results, we suggest that molecules under investigation are suitable donors of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and its derivatives are acceptors of solar cells. © the Owner Societies 2015.

Tian Y.,Beijing Normal University | Jim C.Y.,University of Hong Kong | Tao Y.,Northeast Normal University | Shi T.,Forest Tree and Seedling Administrative General Station of Hubei Provincial Forestry Bureau
Urban Forestry and Urban Greening | Year: 2011

A large body of the literature has assessed the complicated process of landscape fragmentation, while few studies have tackled urban green space (UGS) systems in the urban context, especially in compact cities like Hong Kong. The fragmentation index was modeled using landscape metrics to assess green space fragmentation in Hong Kong. Our results indicate that the set of parameters that can be used to analyze the fragmentation of UGS includes: AREA_MN, PD, SHAPE_MN, ENND_MN, CONNECT, DIVISION, MESH and SPLIT. According to the fragmentation index, five fragmentation levels were identified in the study area. The built-up areas in Kowloon and along the coast of Hong Kong Island exhibited the highest fragmentation level of green spaces, while the countryside of the New Territories had the lowest. The uneven distribution of green cover results in an uneven distribution of UGS fragmentation levels. The eight metrics and the PCA technique employed were validated with respect to their applicability to analyzing green space fragmentation in this study. The results of this study could contribute to our understanding of fragmentation from a landscape ecological perspective. They will also be useful in the appropriate, future planning of urban green spaces to increase connectivity, form green networks and realize sustainability in compact cities. © 2011 Published by Elsevier GmbH.

Guo Q.,U.S. Department of Agriculture | Kelt D.A.,University of California at Davis | Sun Z.,CAS South China Botanical Garden | Liu H.,CAS South China Botanical Garden | And 3 more authors.
Scientific Reports | Year: 2013

While horizontal gradients of biodiversity have been examined extensively in the past, vertical diversity gradients (elevation, water depth) are attracting increasing attention. We compiled data from 443 elevational gradients involving diverse organisms worldwide to investigate how elevational diversity patterns may vary between the Northern and Southern hemispheres and across latitudes. Our results show that most elevational diversity curves are positively skewed (maximum diversity below the middle of the gradient) and the elevation of the peak in diversity increases with the elevation of lower sampling limits and to a lesser extent with upper limit. Mountains with greater elevational extents, and taxonomic groups that are more inclusive, show proportionally more unimodal patterns whereas other ranges and taxa show highly variable gradients. The two hemispheres share some interesting similarities but also remarkable differences, likely reflecting differences in landmass and mountain configurations. Different taxonomic groups exhibit diversity peaks at different elevations, probably reflecting both physical and physiological constraints.

Lv Y.,Changchun Normal University | Sun Z.,Northeast Normal University
European Journal of Soil Science | Year: 2016

This research examines the distribution of bi-conical reflectance of particulate surfaces with different particle sizes by multi-angular reflectance. Two types of particulate samples (called desert and cultivated soil) were sieved to a particle size range of 0.15-0.9 mm. The reflectance factors were measured at 570 or 330 different viewing positions for each illumination angle (45° and 60°). The reflectance was strongly non-Lambertian for all samples, but with markedly different patterns for the two types of particulate surface. Particle size was correlated with the bi-conical reflectance factor (BCRF) and anisotropic reflectance factor (ARF), respectively. The results showed a strong relation between BCRF and particle size in all viewing directions, except for the backward scattering direction, with an average R2 value of 0.9. The use of ARF improved the relation with particle size more in the backward scattering direction in the principal plane than with BCRF (R2 = 0.7 for BCRF; R2 = 0.91 for ARF). However, the strong relation between the ARF and particle size was limited in the forward and backward scattering directions, with an average R2 value of 0.86. The results showed the considerable potential of multi-angular reflectance for quantitative evaluation of the particle size of particulate surfaces. This approach appears to provide a promising empirical and theoretical basis for the future retrieval of soil particle size. Highlights:: The aim is to estimate the particle size from the reflectance of soil samples. Analysis of the relation between particle size and reflectance with multi-angular data. There was a strong relation between reflectance and particle size in 2π space. Multi-angular reflectance has the potential to evaluate quantitatively the particle size of soil. © 2016 British Society of Soil Science.

Wu H.,Northeast Normal University | Liu B.,Northeast Normal University | Yang J.,Northeast Normal University | Liu H.-Y.,Northeast Normal University | Ma J.-F.,Northeast Normal University
CrystEngComm | Year: 2011

A new type of 3D entangled motif constructed from 2D polyrotaxane layers has been synthesized and characterized, which represents the first example of a 2D → 3D polythreaded framework with both polyrotaxane and polypeseudo-rotaxane character. © 2011 The Royal Society of Chemistry.

Jin R.,Northeast Normal University | Jin R.,Chifeng University | Zhang J.,Northeast Normal University
Chemical Physics | Year: 2011

The interactions between chemosensor, 2-(2-hydroxyphenyl)-5-phenyl-1,3,4- oxadiazole (HOXD1), and different halides (F-, Cl-, and Br-) and phosphate (H2PO4-) anions were theoretically investigated. It turned out that the unique selectivity of HOXD1 for F-/H2PO4- is ascribed to its ability of deprotonating the hydroxy group of host sensor. Optical spectra of neutral and deprotonated sensors were simulated using TD-DFT method. It was found that intermolecular proton transfer is responsible for the colorimetric and fluorescent signaling of chemosensor for F-/H2PO4-. Seven derivatives of HOXD1 have been designed. All the mono-electron-donating (-CH3, -OCH3, and -N(CH3)2) substituted derivatives are expected to be promising candidates for ratiometric fluorescent F-/H2PO4- chemosensors as well as chromogenic chemosensors, while para-N(CH 3)2 substituted derivative can serve as chromogenic F-/H2PO4- chemosensor only. Furthermore, the mono-electron-withdrawing (-CN and -COCH3) derivatives are promising electron transport and luminescent materials for OLEDs as well. © 2010 Elsevier B.V. All rights reserved.

Liu Y.,Northeast Normal University | Yang X.,Peking University | Miao J.,Northeast Normal University | Tang Q.,Northeast Normal University | And 2 more authors.
Chemical Communications | Year: 2014

Polyoxometalate-functionalized metal-organic frameworks featuring uniform proton-conducting pathways in three orthogonal directions, good water retention and stability were prepared. The proton conductivity of the hybrid material was observed to increase by 5 orders of magnitude compared to that of the parent material HKUST-1. This journal is © the Partner Organisations 2014.

Dong M.-Y.,Beijing Normal University | Jiang Y.,Beijing Normal University | Zhang D.-Y.,Beijing Normal University | Wu Z.-F.,Northeast Normal University
Theoretical and Applied Climatology | Year: 2013

Daily mean air temperatures from 81 meteorological stations in Northeast China were analyzed for the spatiotemporal change of the climatic growing season during the period 1960-2009. Our results showed that latitude strongly influenced the spatial patterns of the mean start (GSS), end (GSE), and length (GSL) of the growing season. For the area studied, a significant increasing trend in GSL during 1960-2009 was detected at a significance level of 0. 01, especially after the early 1980s. The area-average GSL has extended 13. 3 days during the last 50 years, mainly due to the advanced GSS evident in the spring (7. 9 days). The variations of GSS and GSE were closely correlated with the monthly mean temperature (Tmean) of April and October, respectively, while GSL was closely related to the monthly minimum temperatures (Tmin) of spring (March to April) and autumn (September to October). The distributions of the trends in growing season parameters (GSS, GSE, and GSL) showed great spatial variability over Northeast China. Significant relationships between altitude and the trend rates of the GSS and GSL were detected, while geographic parameters had little direct effect on the change in GSE. This extended growing season may provide favorable conditions for agriculture and forest, and improve their potential production. © 2012 Springer-Verlag.

Tian Y.,Beijing Normal University | Jim C.Y.,University of Hong Kong | Tao Y.,Northeast Normal University
Journal of Urban Planning and Development | Year: 2012

A compact city is a special urban form with inherent physical, social, and institutional constraints on greenery that obstruct the achievement of sustainability. In this study, Hong Kong is used as a case to assess the constraints and challenges related to urban green spaces (UGS) development in compact cities. Strategies to overcome these obstacles and improve the UGS conditions are developed. Opportunities to implement the strategies are then evaluated. Because compact cities have extremely limited space allocated for UGS on the ground level, strategies to optimize the layouts of green spaces and seek additional spaces above or below the ground level, such as vertical green surfaces or structures, green roofs, and podiums, are possible solutions. Measures to implement the strategies are summarized as (1) reorganizing the departments and offices related to UGS and clarifying their individual responsibilities to increase their efficiency; (2) encouraging citizen participation; (3) establishing proper legal basis; (4) forming a comparatively connected comprehensive green network of green sources and green sinks with ground-level green spaces, skyscraper farms, and sky gardens, all with optimal layouts; (5) maintaining and repairing UGS after construction; and (6) selecting species of plants that will thrive in specific green spaces. The compact form of Hong Kong provides many chances to implement these strategies. The study increases understanding of the critical factors behind the success or failure of UGS development in one of the most compact cities in the world and provides suggestions for strategic and policy-related measures for the provision and management of UGS in other congested areas. © 2012 American Society of Civil Engineers.

Ji G.,Peking University | He C.,Northeast Normal University | Tan Y.,Chinese Research Academy of Environmental Sciences
Ecological Engineering | Year: 2013

Real-time PCR was fist used to quantitatively study the spatial distribution of the absolute abundance, relative abundance, and relative richness of amoA, nxrA, narG, napA, nirK, qnorB, nosZ, nas, and nifH genes and anaerobic ammonium oxidation (anammox, or ANO) bacteria in four multimedia biofilters. The results showed that these multimedia biofilters could provide NH4 + and total nitrogen (TN) average removal efficiencies of 88%. Except for nifH, ANO and the other nitrogen removal functional genes all were dominantly enriched in different zones. In fact, ANO, napA, qnorB, nosZ, and nxrA were enriched by 5.6-330.1 times; and nirK, narG, amoA, and nas were enriched by 1.4-2.1 times. In addition, ANO, napA, qnorB, and nosZ showed partially or mutually beneficial cooperation. The nxrA and nirK genes showed protocooperation, and the amoA and narG genes showed partially beneficial cooperation. © 2013 Elsevier B.V.

Peelen M.V.,University of Trento | Bracci S.,University of Trento | Lu X.,Northeast Normal University | He C.,Beijing Normal University | And 3 more authors.
Journal of Cognitive Neuroscience | Year: 2013

Previous studies have provided evidence for a tool-selective region in left lateral occipitotemporal cortex (LOTC). This region responds selectively to pictures of tools and to characteristic visual tool motion. The present human fMRI study tested whether visual experience is required for the development of tool-selective responses in left LOTC. Words referring to tools, animals, and nonmanipulable objects were presented auditorily to 14 congenitally blind and 16 sighted participants. Sighted participants additionally viewed pictures of these objects. In whole-brain group analyses, sighted participants showed toolselective activity in left LOTC in both visual and auditory tasks. Importantly, virtually identical tool-selective LOTC activity was found in the congenitally blind group performing the auditory task. Furthermore, both groups showed equally strong toolselective activity for auditory stimuli in a tool-selective LOTC region defined by the picture-viewing task in the sighted group. Detailed analyses in individual participants showed significant tool-selective LOTC activity in 13 of 14 blind participants and 14 of 16 sighted participants. The strength and anatomical location of this activity were indistinguishable across groups. Finally, both blind and sighted groups showed significant resting state functional connectivity between left LOTC and a bilateral frontoparietal network. Together, these results indicate that toolselective activity in left LOTC develops without ever having seen a tool or its motion. This finding puts constraints on the possible role that this region could have in tool processing and, more generally, provides new insights into the principles shaping the functional organization of OTC. © 2013 Massachusetts Institute of Technology.

Nanao M.H.,Pierre Mendès-France University | Vinos-Poyo T.,French National Institute for Agricultural Research | Brunoud G.,CNRS Laboratory of Plant Reproduction and Development | Thevenon E.,French National Institute for Agricultural Research | And 10 more authors.
Nature communications | Year: 2014

The plant hormone auxin is a key morphogenetic regulator acting from embryogenesis onwards. Transcriptional events in response to auxin are mediated by the auxin response factor (ARF) transcription factors and the Aux/IAA (IAA) transcriptional repressors. At low auxin concentrations, IAA repressors associate with ARF proteins and recruit corepressors that prevent auxin-induced gene expression. At higher auxin concentrations, IAAs are degraded and ARFs become free to regulate auxin-responsive genes. The interaction between ARFs and IAAs is thus central to auxin signalling and occurs through the highly conserved domain III/IV present in both types of proteins. Here, we report the crystal structure of ARF5 domain III/IV and reveal the molecular determinants of ARF-IAA interactions. We further provide evidence that ARFs have the potential to oligomerize, a property that could be important for gene regulation in response to auxin.

Meng X.,Northeast Normal University | Liao P.,Northeast Normal University | Liu J.,Northeast Normal University | Bi X.,Northeast Normal University | Bi X.,Institute of Elemento Organic Chemistry
Chemical Communications | Year: 2014

Divergent syntheses of indolizines and 2,4-disubstituted pyrroles by the silver-catalyzed cyclization of 2-pyridyl alkynyl carbinols with isocyanides are reported. These methods provide an effective route to highly functionalized indolizines and 2,4-disubstituted pyrroles in good to excellent yields. The 2,4-disubstituted pyrroles are synthesized by an unprecedented regioselective [3+2] cycloaddition of terminal alkynes with isocyanides. © 2014 the Partner Organisations.

Zhu T.,Northeast Normal University | Stojmenovic M.,Swinburne University of Technology
Ad-Hoc and Sensor Wireless Networks | Year: 2014

Recently, social-based approaches, which attempt to exploit the social behavior of mobile nodes to guide routing decisions, have attracted lots of attention in routing design of opportunistic networks. This paper presents a survey of the social characteristics shown in opportunistic mobile networks and emphasizes how to measure the social characteristics in time-vary contact graph. It discusses the typical social-based routing protocols and investigates the relationship among the routing performance, the mobility scenarios and routing protocols. This paper is concluded by discussing open questions and challenges in the design of social-based routing protocol between mobile devices. © 2014 Old City Publishing, Inc.

Huang P.,Peking University | Huang P.,Northeast Normal University | Yin M.H.,Northeast Normal University
Science China Information Sciences | Year: 2014

The random constraint satisfaction problem (CSP) instances generated by Model RB have been widely used in the field of CSP and have some nice features. In this paper, we consider two optimization versions of CSP, i.e., the maximum constraint satisfaction problem (Max-CSP) and the minimum satisfaction problem (Min-CSP) of Model RB. The problem of the Max-CSP is how to find an assignment to all the variables such that the maximum number of constraints are satisfied and the problem of Min-CSP is how to find an assignment to all the variables such that the minimum number of constraints are satisfied. We use the first moment method to prove that when r > 2α(1/p-1) (or p > 2α/(2α+r)), an upper bound of Max-CSP can be derived. Similarly, we can prove that when r > 2α(1/p-1) (or p > 2α/(2α + r)), a lower bound of Min-CSP can be derived. © 2014 Science China Press and Springer-Verlag Berlin Heidelberg.

An B.,Key Laboratory for Applied Statistics of Ministry of Education | An B.,Northeast Normal University | Guo J.,Key Laboratory for Applied Statistics of Ministry of Education | Guo J.,Northeast Normal University | Wang H.,Peking University
Computational Statistics and Data Analysis | Year: 2013

The problem of regression shrinkage and selection for multivariate regression is considered. The goal is to consistently identify those variables relevant for regression. This is done not only for predictors but also for responses. To this end, a novel relationship between multivariate regression and canonical correlation is discovered. Subsequently, its equivalent least squares type formulation is constructed, and then the well developed adaptive LASSO type penalty and also a novel BIC-type selection criterion can be directly applied. Theoretical results show that the resulting estimator is selection consistent for not only predictors but also responses. Numerical studies are presented to corroborate our theoretical findings. © 2013 Elsevier B.V. All rights reserved.

Fang H.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Wei S.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Wei S.,Northeast Normal University | Liang S.,University of Maryland University College | Liang S.,Beijing Normal University
Remote Sensing of Environment | Year: 2012

The objective of this paper is to quantitatively validate the global MODIS and CYCLOPES leaf area index (LAI) products using a global LAI field measurement database created on the basis of a literature review and major validation campaigns. The MODIS LAI product suite, containing the Terra Collection 4 (C4), Terra Collection 5 (C5) and Terra. +. Aqua combined C5, was analyzed, with considerable attention paid to the quality control (QC) information. The CYCLOPES V3.1 LAI product was similarly analyzed with regard to the status map (SM) layer. In general, the MODIS LAI has improved consistently over all releases. MODIS C5 data retrieved with the main algorithm (QC < 64) and CYCLOPES data showed a similar range of uncertainties (1.0-1.2). Uncertainties for the best MODIS C5 (QC = 0) and CYCLOPES (SM = 0) estimates were around 0.9-1.1. The overall mean differences between the best MODIS C5 and CYCLOPES were within ± 0.10. The highest correspondence was obtained for woody biomes from the best MCD15 C5 data (RMSE = 0.80). Results indicate that the uncertainties in current LAI products (around ± 1.0) are still unable to meet the accuracy requirement of GCOS (± 0.5). Although there are limitations, we recommend MODIS C5 retrieved with the main algorithm (QC < 64) and CYCLOPES for the user community. This study demonstrates the necessity of exploring uncertainties related to the true and effective LAIs separately, and reveals the importance of referring to the quality assessment information. More field measurements are required for further studies, which should focus on under-sampled biome types and areas. © 2011 Elsevier Inc.

Wu H.,Northeast Normal University | Yang J.,Northeast Normal University | Liu Y.-Y.,Northeast Normal University | Ma J.-F.,Northeast Normal University
Crystal Growth and Design | Year: 2012

Two unusual entangled motifs of [Ag 0.52Na 0.48(β- Mo 8O 26)(H 2O)][Ag 3(Tipa) 2] (1) and [Ag 6(Tipa) 4(β-Mo 8O 26)][H 2(β-Mo 8O 26)]•5H 2O (2) based on a tri(4-imidazolylphenyl)amine (Tipa) ligand and octamolybdate clusters have been successfully synthesized at different pH values. In compound 1, the 1D inorganic chains and 1D ladders are entangled to give a highly novel 1D ladder +1D chain → 3D poly-pseudorotaxane framework. The unusual topological feature of 2 consists of the 2-fold interpenetrated layer, which is further catenated to the two adjacent such sheets in parallel fashion to give an overall unique (2D → 3D) polycatenated framework. The luminescent properties of the compounds have also been investigated. © 2012 American Chemical Society.

Wang L.,Northeast Normal University | Wu Y.,Northeast Normal University | Shan G.-G.,Northeast Normal University | Geng Y.,Northeast Normal University | And 3 more authors.
Journal of Materials Chemistry C | Year: 2014

A series of heteroleptic iridium(iii) complexes were investigated by using the density functional theory/time-dependent density functional theory (DFT/TD-DFT) approach to determine the influence of the diphenylphosphoryl (Ph2PO) moiety on the electronic structures, phosphorescent properties and the organic light-emitting diode (OLED) performance. The results reveal that the introduction of the Ph2PO group could not only dramatically change the electron density distributions of the LUMO and cause red shifts of the emission wavelengths, but also increase the oscillator strengths and the metal character, thus leading to larger radiative decay rates. Additionally, compared with FIrpic (a widely used kind of blue guest material in OLED devices), those complexes with Ph2PO substituents could improve the electron injection/balance ability, increase the Förster energy transfer rate and confine the triplet excitons to the guest phosphors, hence resulting in better OLED performance. Interestingly, further analysis indicates that, compared to IrpicPO with the Ph2PO group sited at the phenyl ring of the phenylpyridine (ppy) ligands, IrpicPOpy with the Ph2PO group sited at the pyridine ring of the ppy ligands performs better in the hole-trapping and hole-injection ability. Finally, we hope our investigations will facilitate the future design of high efficient phosphorescent materials. © 2014 the Partner Organisations.

Wang H.,Peking University | Ji G.,Peking University | Bai X.,Northeast Normal University | He C.,Northeast Normal University
Bioresource Technology | Year: 2015

A study was conducted of treatment performance and nitrogen transformation processes in a trickling filter (TF) used to treat micro-polluted source water under variable hydraulic loading rates (HLRs), ranging from 1.0 to 3.0m3/m2d. The TF achieved high and stable COD (97.7-99.3%) and NH4 +-N (67.3-92.7%) removal efficiencies. Nitrification and anaerobic ammonium oxidation were the dominant nitrogen removal processes in the TF. Path analysis indicated that amoA/anammox and amoA/(narG+napA) were the two key functional gene groups driving the major processes for NH4 +-N and NO2 --N, respectively. The analysis also revealed that anammox/amoA and nxrA/(nirK+nirS) were the two key functional gene groups affecting processes associated with the NO3 --N transformation rate. The direct and indirect effect of functional gene groups further confirmed that nitrogen transformation processes are coupled at the molecular level, resulting in a mutual contribution to nitrogen removal in the TF. © 2014 .

Wu H.,Northeast Normal University | Yang J.,Northeast Normal University | Su Z.-M.,Northeast Normal University | Batten S.R.,Monash University | Ma J.-F.,Northeast Normal University
Journal of the American Chemical Society | Year: 2011

Entanglement is one of the most important features of coordination polymer frameworks and has attracted considerable attention due to its aesthetic and topological interest. Among entangled systems, interpenetrating frameworks represent an intriguing subset; however, there are few examples of materials containing very high levels of interpenetration. In this work a coordination polymer with 103-srs topology, constructed from a star-like tridentate ligand, tri(4-imidazolylphenyl)amine, and AgI ions, has been hydrothermally synthesized. It contains a record 54 interpenetrating networks. © 2011 American Chemical Society.

Wang Z.,CAS Changchun Institute of Applied Chemistry | Bi X.,Northeast Normal University | Bi X.,Institute of Elemento organic Chemistry | Liao P.,Northeast Normal University | And 4 more authors.
Chemical Communications | Year: 2012

A catalytic and highly efficient Wolff's cyclocondensation of α-diazoketones with aromatic and aliphatic amines has been realized for the first time by utilizing the strategy of an intramolecular hydrogen bonding-activating carbonyl group. This approach successfully solved the challenging problem of poor condensation efficiency in Wolff 1,2,3-triazole synthesis, and constitutes a powerful method for the synthesis of highly functionalized 1,2,3-triazoles. © The Royal Society of Chemistry 2012.

Zhou M.,Northeast Normal University | Wang H.-L.,Los Alamos National Laboratory | Guo S.,Peking University
Chemical Society Reviews | Year: 2016

One of the critical issues in the industrial development of fuel cells (e.g., proton exchange membrane fuel cells, direct methanol fuel cells and biofuel cells) is the high cost, serious intermediate tolerance, anode crossover, sluggish kinetics, and poor stability of the platinum (Pt) as the preferred electrocatalysts for the oxygen reduction reaction (ORR) at the cathode. The development of novel noble-metal-free electrocatalysts with low cost, high activity and practical durability for ORR has been considered as one of the most active and competitive fields in chemistry and materials science. In this critical review, we will summarize recent advances on engineering advanced carbon nanomaterials with different dimensions for the rational design and synthesis of noble-metal-free oxygen reduction electrocatalysts including heteroatom-doped carbon nanomaterials, transition metal-based nanoparticle (NP)-carbon nanomaterial composites and especially the stable iron carbide (Fe3C)-based NP-carbon nanomaterial composites. Introducing advanced carbon nanomaterials with high specific surface area and stable structure into the noble-metal-free ORR field has not only led to a maximized electrocatalyst surface area for the electron transfer but also resulted in enhanced electrocatalyst stability for long-term operation. Therefore, the rational design and synthesis of noble-metal-free electrocatalysts based on heteroatoms, transition metal-based NPs and Fe3C-based NP functionalized carbon nanomaterials are of special relevance for their ORR applications, and represents a rapidly growing branch of research. The demonstrated examples in this review will open new directions on designing and optimizing advanced carbon nanomaterials for the development of extremely active and durable earth-abundant cathodic catalysts for fuel cell applications. © The Royal Society of Chemistry 2016.

Agency: European Commission | Branch: FP7 | Program: CSA-SA | Phase: ENV.2008. | Award Amount: 1.11M | Year: 2009

The general objective of PRACTICE is to link S & T advances and traditional knowledge on prevention and restoration practices to combat desertification with sound implementation, learning and adaptive management, knowledge sharing, and dissemination of best practices. Specific objectives are: 1. To create an international platform of long-term monitoring sites for assessing and investigating practices to combat desertification. 2. To develop integrated evaluation tools to assess the cost-effectiveness of practices to combat desertification, taking into account changes in both biophysical and socio-economic properties, by synergistically exploiting the recent advances on assessment and evaluation methodologies and approaches. 3. To assess prevention and restoration practices to combat desertification for croplands, rangelands and woodlands, considering the impacts on socio-economic status, soil functions, biodiversity, and ecosystem services. 4. To identify and document best practices to combat desertification considering multiple purposes at different spatial (local to global) scales, and to establish cost-effective thresholds for the various management alternatives. 5. To develop education material and translational science strategies, and implement innovative participatory approaches to link science to society, to share and transfer evaluation methods and best practices, addressing and involving stakeholders at all levels, from farmers to local organisations, to national and international bodies.

Shao X.-Q.,Northeast Normal University | Shao X.-Q.,National University of Singapore | You J.-B.,National University of Singapore | Zheng T.-Y.,Northeast Normal University | And 2 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

We extend the recent result of a bipartite Bell singlet [A. W. Carr and M. Saffman, Phys. Rev. Lett. 111, 033607 (2013)PRLTAO0031-900710.1103/PhysRevLett. 111.033607] to a stationary three-dimensional entanglement between two-individual neutral Rydberg atoms. This proposal makes full use of the coherent dynamics provided by a Rydberg-mediated interaction and the dissipative factor originating from the spontaneous emission of a Rydberg state. The numerical simulation of the master equation reveals that both the target state negativity N(ρ̂â̂ ) and fidelity F(ρ̂â̂ ) can exceed 99.90%. Furthermore, a steady three-atom singlet state |S3⌠is also achievable based on the same mechanism. © 2014 American Physical Society.

Shao X.-Q.,Northeast Normal University | Shao X.-Q.,National University of Singapore | Zheng T.-Y.,Northeast Normal University | Oh C.H.,National University of Singapore | Zhang S.,Yanbian University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

We present a dissipative protocol to engineer two 87Rb atoms into a form of three-dimensional entangled state via spontaneous emission. The combination of coupling between ground states via microwave fields and dissipation induced by spontaneous emission makes the current scheme deterministic and a stationary entangled state is always achievable without state initialization. Moreover, this scheme can be straightforwardly generalized to preparation of an N-dimensional entangled state in principle. © 2014 American Physical Society.

Pan D.,Northeast Normal University | Ma S.,Jilin Entry Exit Inspection and Quarantine Bureau | Bo X.,Northeast Normal University | Guo L.,Northeast Normal University
Microchimica Acta | Year: 2011

Ordered mesoporous carbon (OMC) was synthesized and used to modify the surface of a glassy carbon (GC) electrode. Due to the unique properties of OMC, a decrease in the overvoltage of the reduction potential of methyl parathion (MP) (to ca. 219 mV) and a 76-fold increase in the peak current are observed (compared with a bare GC electrode). The absorption capacity of the surface of the electrode for MP was determined by chronocoulometry. The results show that the γ value of the modified electrode (2.34 × 10-9 mol cm-2) is 9.5 times as large as that of the GC electrode (2.47 × 10-10 mol cm-2). The new electrode exhibits synergistic electrocatalytic and accumulative effects on MP. MP can be determined by linear sweep voltammetry (LSV) which displays a linear relationship between peak current and MP concentration in the range from 0. 09 to 61 μM, with a detection limit as low as 7.6 nM (at an S/N of 3) and after an accumulation at 0 V for 5 min. The electrode was successfully applied to the determination of MP in spiked lake water samples. © 2011 Springer-Verlag.

Li G.,Jilin University | Zhu D.,Northeast Normal University | Peng T.,Jilin University | Liu Y.,Jilin University | And 2 more authors.
Advanced Functional Materials | Year: 2014

Two phosphorescent iridium complexes with bipolar transporting ability, namely FPPCA (500 nm) and BZQPG (600 nm), are synthesized and employed as an ideal host-guest system for phosphorescent organic light emitting diodes (PHOLEDs).The devices give very high-efficiency orange-red emission from BZQPG with maximum external quantum efficiency (EQE orext) of >27% and maximum power efficiency (PE or ηp) of >75 lm/W, and maintain high levels of 26% and 55 lm/W, 25% and 40 lm/W at high luminance of 1000 and 5000 cd m-2, respectively, within a range of 8-15 wt% of BZQPG. The realization of such high and stable EL performance results from the coexistence of two parallel paths: i) effective energy transfer from host (FPPCA) to guest (BZQPG) and ii) direct exciton formation on the BZQPG emitter, which can alternately dominate the electrophosphorescent emission. This all-phosphor doping system removes the charge-injection barrier from the charge-transport process to the emissive layer (EML) due to the inherent narrow E g of both phosphors. Therefore, this ideal host-guest system represents a new design to produce PHOLEDs with high efficiency and low efficiency roll-off using a simple device configuration. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ma P.,CAS Changchun Institute of Applied Chemistry | Xiao H.,University of Notre Dame | Li X.,Northeast Normal University | Li C.,CAS Changchun Institute of Applied Chemistry | And 5 more authors.
Advanced Materials | Year: 2013

By combining upconversion nanoparticles with the cisplatin (IV) prodrug we have demonstrated that a stable and multifunctional drug delivery system can be designed that will both reduce the drawbacks of cisplatin and give insight in to its in vitro/in vivo imaging. The up/down-conversion fluorescence are detectable and show obvious co-localization, demonstrating that the nanoparticles are rather stable inside cells and retain the UCNPs and block copolymer. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tian J.,Northeast Normal University | Li B.,Northeast Normal University | Li B.,Hebei United University | Zhang X.,Northeast Normal University | And 2 more authors.
Dalton Transactions | Year: 2013

Three novel one-dimensional (1D) lanthanide coordination complexes involving the 4-methyl-3-nitrobenzoic acid (HL) ligand, with the general formulae [Gd(L)3(H2O)(CH3OH)] (1), [Gd(L) 3(H2O)2]·(4,4′-bpy)·CH 3OH (2), [Dy(L)3(H2O)(CH3OH)] (3), have been synthesized by solvothermal reactions. These complexes have been structurally characterized by single-crystal X-ray diffraction, IR, PXRD, TGA, and elemental analysis. Complexes 1 and 3 are isostructural except for the distinction of the metal ion. Magnetic measurements indicate that complexes 1-3 show antiferromagnetic behaviors. Complex 3 behaves with slow relaxation of the magnetization, where the frequency-dependent out-of-phase signals are noticed. However, the characteristic maxima were not reached above 2 K under zero direct current (DC) fields. When a DC field of 5000 Oe was employed, the frequency dependent peaks of alternating current (AC) signals were obtained. © 2013 The Royal Society of Chemistry.

Sun F.-J.,University of Illinois at Urbana - Champaign | Sun F.-J.,Northeast Normal University | Caetano-Anolles G.,University of Illinois at Urbana - Champaign
BMC Bioinformatics | Year: 2010

Background: Ribonuclease P is an ancient endonuclease that cleaves precursor tRNA and generally consists of a catalytic RNA subunit (RPR) and one or more proteins (RPPs). It represents an important macromolecular complex and model system that is universally distributed in life. Its putative origins have inspired fundamental hypotheses, including the proposal of an ancient RNA world.Results: To study the evolution of this complex, we constructed rooted phylogenetic trees of RPR molecules and substructures and estimated RPP age using a cladistic method that embeds structure directly into phylogenetic analysis. The general approach was used previously to study the evolution of tRNA, SINE RNA and 5S rRNA, the origins of metabolism, and the evolution and complexity of the protein world, and revealed here remarkable evolutionary patterns. Trees of molecules uncovered the tripartite nature of life and the early origin of archaeal RPRs. Trees of substructures showed molecules originated in stem P12 and were accessorized with a catalytic P1-P4 core structure before the first substructure was lost in Archaea. This core currently interacts with RPPs and ancient segments of the tRNA molecule. Finally, a census of protein domain structure in hundreds of genomes established RPPs appeared after the rise of metabolic enzymes at the onset of the protein world.Conclusions: The study provides a detailed account of the history and early diversification of a fundamental ribonucleoprotein and offers further evidence in support of the existence of a tripartite organismal world that originated by the segregation of archaeal lineages from an ancient community of primordial organisms. © 2010 Sun and Caetano-Anollés; licensee BioMed Central Ltd.

Zeng T.,CAS Research Center for Eco Environmental Sciences | Zhang X.,CAS Research Center for Eco Environmental Sciences | Zhang X.,Hebei United University | Wang S.,Northeast Normal University | And 3 more authors.
Journal of Materials Chemistry A | Year: 2013

A facile method is proposed to fabricate yolk-shell microspheres consisting of a movable silica core, a multifunctional double-layered shell, and plenty of tiny gold nanoparticles (Au NPs, ∼2 nm) confined within the interior cavity and the mesoporous shell. The presented strategy involves the one-step coating of a Fe3O4/carbon double-layered shell, the partial etching of the silica cores and the in situ immobilization of Au NPs. The inner Fe3O4 layer of the double-layered shell endows the composites with superparamagnetism and thereby simplifies the introduction procedure of a magnetic component. The outer carbon layer not only protects the Fe3O4 layer from outside harsh conditions but also provides additional adsorption sites for Au NPs besides the interior space. The large number of catalytic active sites together with the advantages of the yolk-shell architecture make the nanocomposite a perfect catalyst for the reduction of 4-nitrophenol to 4-aminophenol in the presence of NaBH4 (TOF value is 17.4 min-1). Moreover, the synthesized catalyst can be easily recovered and reused for at least nine cycles due to its magnetically separable feature and good stability. These confirm that the as-prepared yolk-like nanocomposites are promising candidates for catalytic application. © 2013 The Royal Society of Chemistry.

Zhang J.,Northeast Normal University | Zhou L.,Northeast Normal University | Al-Attar H.A.,Durham University | Shao K.,Northeast Normal University | And 5 more authors.
Advanced Functional Materials | Year: 2013

Eight new iridium(III) complexes 1-8, with 1,3,4-oxadiazole (OXD) derivatives as the cyclometalated C^N ligand and/or the ancillary N^N ligands are synthesized and their electrochemical, photophysical, and solid-state light-emitting electrochemical cell (LEC) properties are investigated. Complexes 1, 2, 7 and 8 are additionally characterized by single crystal X-ray diffraction. LECs based on complexes 1-8 are fabricated with a structure indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/cationic iridium complex:ionic liquid/Al. LECs of complexes 1-6 with OXD derivatives as the cyclometalated ligands and as the ancillary ligand show yellow luminescence (λmax = 552-564 nm). LECs of complexes 7 and 8 with cyclometalated C^N phenylpyridine ligands and an ancillary N^N OXD ligand show red emission (λmax 616-624 nm). Using complex 7 external quantum efficiency (EQE) values of >10% are obtained for devices (210 nm emission layer) at 3.5 V. For thinner devices (70 nm) high brightness is achieved: red emission for 7 (8528 cd m-2 at 10 V) and yellow emission for 1 (3125 cd m-2 at 14 V). 2,5-Diaryl-1,3,4-oxadiazole derivatives are shown to be versatile cyclometalating C^N and coordinating N^N ligands for ionic iridium complexes that are fabricated into light-emitting electrochemical cells (LECs). High brightness red emission from a LEC at a driving voltage of 10 V is observed. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tian J.,Northeast Normal University | Li W.,Northeast Normal University | Li B.,Hebei United University | Zhang X.,Northeast Normal University | And 2 more authors.
Chemistry - A European Journal | Year: 2013

We have synthesized a microporous magnetic framework that contained supertetrahedral decametallic cobalt clusters as nodes and 4- (tris(hydroxymethyl)methyl)pyridine ligands as linkers in a NaCl-like network. This complex shows canted antiferromagnetism with spin-glass behavior. After the removal of the guest molecules, the spin-canting and spinglass behaviors are maintained. The permanent porosity was evaluated by N2-adsorption measurements. This complex mainly shows a hydrophobic nature, as validated by MeOH- and water-adsorption measurements, which is consistent with the grand canonical Monte Carlo (GCMC) theoretical simulation. © 2013 Wiley-VCH Verlag GmbHandCo.

Niu H.,CAS Research Center for Eco Environmental Sciences | Wang S.,CAS Research Center for Eco Environmental Sciences | Wang S.,Northeast Normal University | Zhou Z.,CAS Research Center for Eco Environmental Sciences | And 3 more authors.
Analytical Chemistry | Year: 2014

In this work, we have developed a novel sensing strategy employing mixed poly(ethylene glycol)-terminated (PEG-thiols) and perfluoroalkyl-terminated (F-thiols) alkanethiols modified gold nanoparticles (Au@PEG-F NPs) as a probe to detect perfluorinated compounds (PFCs) from water samples. PEG-thiols with high density and long carbon chains make the Au NPs probe well-dispersed in solution and stable even in high concentration of salt solution; F-thiols provide specific fluorous-fluorous interactions to PFCs, which results in adsorption of PFCs on Au@PEG-F NPs. The adsorbed PFCs cause the aggregation of Au@PEG-F NPs probes and thus induce the insolubility of probes and precipitation directly from reaction solution due to the superhydrophobicity of perfluorocarbon monolayers, leading to color and absorbance response of the assay to PFCs. The preparation of the Au@PEG-F NPs probe is very simple, and the colorimetric assay based on this mechanism for the detection of PFCs is selective and convenient. Combined with UV-vis spectrophotometry, the assay demonstrates good sensitivities to PFCs with wide linear range. In the designed concentration range, the response of the colorimetric assay to long-chain PFCs (perfluoroalkyl chain ≥7) is discerned even as the concentration of these PFCs is as low as 10 μg L-1. This low-cost and sensitive assay shows great potential to measure total PFCs in water samples. To the best of our knowledge, this is the first application of the specific fluorous-fluorous interactions and Au NPs based probes for colorimetric recognition for PFCs. © 2014 American Chemical Society.

Xiao H.,University of Notre Dame | Stefanick J.F.,University of Notre Dame | Jia X.,CAS Changchun Institute of Applied Chemistry | Jing X.,CAS Changchun Institute of Applied Chemistry | And 3 more authors.
Chemical Communications | Year: 2013

Nanoparticles formed via electrostatic interactions between methoxy-polyethylene glycol-block-poly(glutamic acid) (MPEG-PGA) and a multinuclear platinum(ii) drug, di-cisPt, exhibit efficient platinum loading, improved cellular uptake, in vitro cytotoxicity, and enhanced in vivo efficacy. © 2013 The Royal Society of Chemistry.

Lv S.,Northeast Normal University | Lv S.,Jilin University | Wang C.,Northeast Normal University | Wang C.,Harbin Normal University | Xing S.,Northeast Normal University
Journal of Alloys and Compounds | Year: 2014

Uniform NiO hierarchical nanostructures assembled by NiO nanosheets have grown directly on nickel foam substrate via a mild hydrothermal reaction between nickel salts and hexamethylenetetramine (HMT), followed by a subsequent calcinations process. HMT was employed as both alkaline source and complex agent. Several kinds of nickel salts (NiSO4, Ni(NO3) 2, NiCl2 or Ni(CH3COO)2) were introduced as nickel source to investigate their effect on the morphology and electrochemical performances of NiO nanostructure. Cyclic voltammetry and constant current charge-discharge measurement illustrated these NiO electrodes presented good electrochemical performance. Especially the electrode with NiSO4 as nickel source gave a maximum specific capacitance of 349 F g-1 at a current density of 0.25 A g-1, which was superior to others owing to the smaller particle size that provided more active sites to ensure sufficient Faradaic reaction. © 2014 Elsevier B.V. All rights reserved.

Luo S.,Northeast Normal University | Chai F.,Harbin Normal University | Zhang L.,Northeast Normal University | Wang C.,Northeast Normal University | And 3 more authors.
Journal of Materials Chemistry | Year: 2012

In this work, we have developed a facile and rapid synthesis of urchin-shaped Fe 3O 4@Bi 2S 3 core-shell hierarchical structures through a sonochemical method. The as-prepared Fe 3O 4@Bi 2S 3 hierarchical core-shell structures show excellent photocatalytic efficiency for the degradation of rhodamine B (RhB) and retained this photocatalytic activity after being recycled five times with the help of an external magnetic field. The possible mechanism for the formation of the urchin-shaped Fe 3O 4@Bi 2S 3 core-shell structures is also proposed. These novel urchin-shaped Fe 3O 4@Bi 2S 3 core-shell structures may have potential applications in water treatment, sensors, and energy storage. © 2012 The Royal Society of Chemistry.

Yang J.,Northeast Normal University | Ma J.-F.,Northeast Normal University | Batten S.R.,Monash University | Ng S.W.,University of Malaya | Liu Y.-Y.,Northeast Normal University
CrystEngComm | Year: 2011

An unusual case of supramolecular isomers has been synthesized and characterized, where the α structure represents the first example of 3-fold interpenetrating 8-connected hex-c3 nets in MOFs and the β phase displays 4-fold interpenetration of a new 65.8 topology. © The Royal Society of Chemistry 2011.

Chai F.,Northeast Normal University | Chai F.,Harbin Normal University | Wang C.,Northeast Normal University | Wang T.,Northeast Normal University | And 2 more authors.
Nanotechnology | Year: 2010

A simple, cost-effective yet rapid and sensitive colorimetric sensor for the detection of Hg2+ using L-cysteine functionalized gold nanoparticles induced by ultraviolet radiation was developed. The sensitivity and selectivity of detection was also investigated. The L-cysteine modified gold nanoparticles can be induced to aggregate quickly in the presence of Hg 2+, especially with the assistance of ultraviolet radiation. The presence of Hg2+ can be monitored by the colorimetric response of gold nanoparticles. The detection of Hg2+ could be realized, after measuring the UV-vis spectra, with a detection limit of 100nM. The selectivity of this method has been investigated by other divalent metal ions. The effective colorimetric sensor can be used for on-site and real-time Hg2+ detection. © 2010 IOP Publishing Ltd.

Yang X.,Harbin Normal University | Wang J.,Harbin Normal University | Su D.,Harbin Normal University | Xia Q.,Harbin Normal University | And 3 more authors.
Dalton Transactions | Year: 2014

Rapid and sensitive detection of 2,4,6-trinitrotoluene (TNT) and 4-nitrophenol (4-NP) has attracted considerable attention due to their wide applications as nitroaromatic explosive materials. A novel fluorescence method for TNT and 4-NP based on bovine serum albumin functionalized fluorescent gold nanoclusters (BSA Au-NCs) has been developed. The detection probe BSA Au-NCs can be used as a fluorescent probe for the sensitive and selective detection of TNT and 4-NP simultaneously. A good linearity of fluorescence detection using BSA Au-NCs as a fluorescent probe was observed for TNT and 4-NP concentrations in the range of 10-8-5 × 10-5 M and 10-9-5 × 10-5 M, with a detection limit of 10 nM and 1 nM, respectively. The high specificity of TNT and 4-NP with BSA Au-NCs interactions provided excellent selectivity towards detecting TNT and 4-NP over other relevant nitroaromatic compounds. This system can be applied to test strips to detect TNT and 4-NP with high sensitivity and selectivity. The vapour of TNT and 4-NP can be detected using BSA Au-NCs test paper within 1 min with a detection limit of 10 pM and 1 pM. © 2014 The Royal Society of Chemistry.

Luo X.,Northeast Normal University | Luo X.,Yili Normal University | Li F.,Northeast Normal University | Xu B.,Northeast Normal University | And 2 more authors.
Journal of Materials Chemistry | Year: 2012

A photovoltaic electrode consisting of polyoxometalate (SiW 12) and zinc oxide (ZnO) was fabricated on indium tin oxide (ITO) glass by one-step electrodeposition. The addition of SiW 12 strongly influences the morphology and crystallographic orientation of the ZnO. The photovoltaic properties of the ZnO film and the SiW 12-ZnO composite films were investigated via solar cell assembly. Both transient photocurrent and current-voltage curve measurements demonstrate that the photocurrent and power conversion efficiency of the SiW 12-ZnO composite film were markedly enhanced in comparison with that of the ZnO film. Based on the results of fluorescence quenching measurements, the enhanced photovoltaic effect should be attributed to the occurrence of the photoinduced electron transfer between polyoxometalate and ZnO, which increases the efficient dissociation of excited electron-hole pairs (excitons). This journal is © The Royal Society of Chemistry 2012.

Feng G.,Northeast Normal University | Guo J.,Northeast Normal University | Jing B.-Y.,Hong Kong University of Science and Technology | Hao L.,Northeast Normal University
Information Processing and Management | Year: 2012

The automated classification of texts into predefined categories has witnessed a booming interest, due to the increased availability of documents in digital form and the ensuing need to organize them. An important problem for text classification is feature selection, whose goals are to improve classification effectiveness, computational efficiency, or both. Due to categorization unbalancedness and feature sparsity in social text collection, filter methods may work poorly. In this paper, we perform feature selection in the training process, automatically selecting the best feature subset by learning, from a set of preclassified documents, the characteristics of the categories. We propose a generative probabilistic model, describing categories by distributions, handling the feature selection problem by introducing a binary exclusion/inclusion latent vector, which is updated via an efficient Metropolis search. Real-life examples illustrate the effectiveness of the approach. © 2011 Elsevier Ltd. All rights reserved.

Yang J.,Northeast Normal University | Ma J.-F.,Northeast Normal University | Batten S.R.,Monash University
Chemical Communications | Year: 2012

Polyrotaxane metal-organic frameworks (PMOFs), a relatively rare branch of entangled networks, have received significant attention due to their unusual entanglement topologies. The PMOFs we described here are still at an early stage of development. This feature article summarizes the recent developments in structural types of PMOFs from our own group and others. We make some generalizations about the various classes of PMOFs, and develop the definitions and nomenclature of these entanglements, including classification into trivial and nontrivial polyrotaxanes, and limits on what constitutes a (nontrivial) polyrotaxane. Finally, the synthetic strategies toward the design and preparation of new PMOFs are elucidated. © 2012 The Royal Society of Chemistry.

Zhang C.-J.,Northeast Normal University | Zhang C.-J.,Heilongjiang University of Chinese Medicine | Pang H.-J.,Harbin University of Science and Technology | Tang Q.,Northeast Normal University | Chen Y.-G.,Northeast Normal University
Dalton Transactions | Year: 2012

Five new hybrid compounds based on Keggin polyanions, Ag +/Cu+ ions and 1,3-bis(1,2,4-triazol-1-yl)propane (btp) molecules have been hydrothermally synthesized. In [Ag5(btp) 4(H2O)2][PCuW11O39] ·2H2O (1), [Ag4.33Na0.67(btp) 4(H2O)2][PMnMo11O 39]·H2O (2) and [Cu4(btp) 4Na(H2O)2][PMnMo11O 39]·2H2O (3), the neighboring mono-substituted Keggin clusters are alternately connected via sharing oxygen atoms to form an unusual Keggin-based transition-metal monosubstituted chain, in which the Keggin cluster serves as a decadentate ligand and grafts ten metal atoms representing the highest connected number for Keggin cluster and forming a 3D framework. In [Ag5(btp)4][PWVI 10WV 2O40] (4) and [Ag5(btp)4][PMo VI 10MoV 2O40] (5), two-electron reduced Keggin clusters as hexadentate linkages are inserted in the rhomboid-like tunnels of the Ag-btp framework and connect with the framework via six Ag-O bonds to achieve 3D motifs, which are new and rare examples of heteropoly blue based hybrid compounds. The successful synthesis of the five high-dimensional structures may provide a feasible route for us to approach 3D polyoxometalate-based hybrids by using substituted Keggin anions and heteropoly blues with high charge density. Furthermore, photocatalytic experiments indicate that both 1 and 4 have good activities for photocatalytic degradation of RhB under UV irradiation. The luminescent properties of compounds 1-5 in the solid state were also investigated. © 2012 The Royal Society of Chemistry.

Chai F.,Northeast Normal University | Chai F.,Harbin Normal University | Wang C.,Northeast Normal University | Wang T.,Northeast Normal University | And 2 more authors.
ACS Applied Materials and Interfaces | Year: 2010

A facile, cost-effective and sensitive colorimetric detection method for Pb2+ has been developed by using glutathione functionalized gold nanoparticles (GSH-GNPs). The sensitivity and selectivity of detection were investigated in detail. The GSH-GNPs could be induced to aggregate immediately in the presence of Pb2+, especially after the addition of 1 M NaCl aqueous solution. The Pb2+ could be detected by colorimetric response of GNPs that could be monitored by a UV-vis spectrophotometer or even naked eyes, and the detection limit could reach 100 nM. The GSH-GNPs bound by Pb 2+ showed excellent selectivity compared to other metal ions (Hg 2+, Mg2+, Zn2+, Ni2+, Cu 2+, Co2+, Ca2+, Mn2+, Fe 2+, Cd2+, Ba2+, and Cr3+), which led to prominent color change. This provided a simple and effective colorimetric sensor (no enzyme or DNA) for on-site and real-time detection of Pb 2+. Most importantly, this probe was also applied to determine the Pb2+ in the lake samples with low interference and high sensitivity. © 2010 American Chemical Society.

Zhong S.,Boyce Thompson Institute for Plant Research | Zhong S.,Northeast Normal University | Fei Z.,Boyce Thompson Institute for Plant Research | Fei Z.,U.S. Department of Agriculture | And 11 more authors.
Nature Biotechnology | Year: 2013

Ripening of tomato fruits is triggered by the plant hormone ethylene, but its effect is restricted by an unknown developmental cue to mature fruits containing viable seeds. To determine whether this cue involves epigenetic remodeling, we expose tomatoes to the methyltransferase inhibitor 5-azacytidine and find that they ripen prematurely. We performed whole-genome bisulfite sequencing on fruit in four stages of development, from immature to ripe. We identified 52,095 differentially methylated regions (representing 1% of the genome) in the 90% of the genome covered by our analysis. Furthermore, binding sites for RIN, one of the main ripening transcription factors, are frequently localized in the demethylated regions of the promoters of numerous ripening genes, and binding occurs in concert with demethylation. Our data show that the epigenome is not static during development and may have been selected to ensure the fidelity of developmental processes such as ripening. Crop-improvement strategies could benefit by taking into account not only DNA sequence variation among plant lines, but also the information encoded in the epigenome. © 2013 Nature America, Inc. All rights reserved.

Millimouno F.M.,Northeast Normal University | Millimouno F.M.,Jilin University | Millimouno F.M.,Higher Institute of Science | Dong J.,Northeast Normal University | And 3 more authors.
Cancer Prevention Research | Year: 2014

Although the incidences are increasing day after day, scientists and researchers taken individually or by research group are trying to fight against cancer by several ways and also by different approaches and techniques. Sesquiterpenes, flavonoids, alkaloids, diterpenoids, and polyphenolic represent a large and diverse group of naturally occurring compounds found in a variety of fruits, vegetables, and medicinal plants with various anticancer properties. In this review, our aim is to give our perspective on the current status of the natural compounds belonging to these groups and discuss their natural sources, their anticancer activity, their molecular targets, and their mechanism of actions with specific emphasis on apoptosis pathways, which may help the further design and conduct of preclinical and clinical trials. Unlike pharmaceutical drugs, the selected natural compounds induce apoptosis by targeting multiple cellular signaling pathways including transcription factors, growth factors, tumor cell survival factors, inflammatory cytokines, protein kinases, and angiogenesis that are frequently deregulated in cancers and suggest that their simultaneous targeting by these compounds could result in efficacious and selective killing of cancer cells. This review suggests that they provide a novel opportunity for treatment of cancer, but clinical trials are still required to further validate them in cancer chemotherapy. ©2014 AACR.

Jiang S.-C.,Northeast Normal University | He N.-P.,CAS Institute of Botany | Wu L.,Northeast Normal University | Zhou D.-W.,CAS Changchun Northeast Institute of Geography and Agroecology
Applied Vegetation Science | Year: 2010

Questions: What factors limit vegetation restoration of secondary bare saline-alkaline patches (BSAP) in the Songnen grassland of northeast China? Is there any adaptive approach to promote revegetation in the shortest time possible and at a low cost? Location: Northeast China. Methods: Considering the climate, soil saline-alkalization and available seed sources, a new approach was adopted to restore vegetation in BSAP, which were formed by the degradation of typical Leymus chinensis grasslands owing to long-term overgrazing. The experimental treatments included no treatment (CK), fencing (F), fencing+inserting cornstalks (FS), fencing+inserting cornstalks+sowing L. chinensis (FSL) and fencing+inserting cornstalks+sowing Puccinellia chinampoensis (FSP). The assumptions behind inserting cornstalks were not only that they would create safe sites for initial revegetation but also that they would enhance seed input by trapping and containing the seeds from seed movement on the BSAP surface. Results: Seed bank shortage was an important factor limiting initial revegetation in BSAP; seed movement on the BSAP surface could provide the necessary seed source if it were contained by effective measures. Vegetation at the sites FS, FSL and FSP was restored well in terms of the above-ground biomass and coverage. Inserted cornstalks acted as safe sites that enhanced the plant survival rate in BSAP; they also enhanced the ability to contain seed movement, thus providing a seed source for initial revegetation. Along with initial revegetation, tussocks around cornstalks can provide better safe sites, which in turn can accelerate subsequent vegetation restoration in BSAP. Conclusions: The approach entails the strategic use of diverse seed sources and the construction of safe sites with agricultural byproducts (cornstalks); therefore, it is a low-cost method and can be used on a widespread scale. The results provide vigorous support in favor of vegetation restoration in BSAP and severely degraded grasslands in the region. In practice, this approach can be used in degraded ecosystems with compacted soil surfaces (including arid and salt-affected soils) to promote revegetation in various regions. © 2009 International Association for Vegetation Science.

Emeline A.V.,Saint Petersburg State University | Zhang X.,Northeast Normal University | Murakami T.,Kanagawa Academy Of Science And Technology | Fujishima A.,Tokyo University of Science
Journal of Hazardous Materials | Year: 2012

Photodegradation of phenol and 4-chlorophenol over six different TiO 2 samples was tested in order to establish whether an interconnection between the activity and selectivity of photocatalysts exists. The obtained experimental data were analyzed using correlation analysis. Some correlations between the activity in phenol(s) photodegradation and selectivity toward formation of primary intermediate products were established. The type of correlations depends on the type of studied photoreactions. The discussion of the observed correlations between the activity and selectivity of photocatalysts is given in terms of the difference of surface concentrations of electrons and holes and corresponding surface active sites which might be dependent on the types of dominating surface faces. On the basis of the obtained results of correlation analysis it was assumed that a higher activity of photocatalysts could be achieved provided that both reduction and oxidation reaction pathways occur with equally high efficiency. © 2011 Elsevier B.V.

Li G.,Yellow River Conservancy Commission | Li G.,Northeast Normal University | Sheng L.,Northeast Normal University
Science China Technological Sciences | Year: 2011

Water-sediment regulation of the Yellow River is to regulate and control the flow and sediment transport relationship of the lower reaches through reservoirs on the main streams and tributaries to create balance between water and sediment so that sediment transport capacity of the downstream channels can be maximized, shrinking of channels be contained, and medium flood channel be restored and maintained. Many years' research by the Yellow River Conservancy Commission (YRCC) reveals the water and sediment transport relationship that will prevent sedimentation at the downstream river channels. Based on this relationship and coming sediment and water conditions in the Yellow River basin, the YRCC, with maximized use of reservoirs on the main streams and tributaries, has developed three models of water-sediment regulation: single Xiaolangdi Reservoir-dominated regulation, space scale water-sediment match, and mainstream reservoirs joint operation. Ten water-sediment regulations based on these three models have resulted in an average drop of 1.5 m in the main channel of the downstream 800 km river and an increase of carrying capacity from 1800 to 4000 m3/s. Besides, the wetland ecosystems of estuarine delta has also been improved and restored significantly. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg.

Wang Z.,Northeast Normal University | Wang Z.,Harbin Normal University | Pei D.,Northeast Normal University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2010

In this Letter, we investigate the ruled null surfaces of the principal normal indicatrix of a null Cartan curve in de Sitter 3-space, an important vacuum solution to Einstein's equations of general relativity with cosmological terms. We classify the singularities of the ruled null surfaces and reveal the relationships between the singularities of the ruled null surfaces and the differential geometric invariants of null Cartan curves by applying the singularity theory. The primary approach is based on the classical unfolding theorem in singularity theory, which has been extensively applied in studying singularity problems in Euclidean space and Minkowski space. This study shows that singularities of the ruled null surfaces and differential geometric invariants of null Cartan curves are deeply related to the order of the contact between the binormal indicatrix of null Cartan curve and the pseudo-sphere contained in the nullcone. © 2010 Elsevier B.V. All rights reserved.

Shen Y.,Northeast Normal University | Peng J.,Northeast Normal University | Zhang H.,Northeast Normal University | Yu X.,Northeast Normal University | Bond A.M.,Monash University
Inorganic Chemistry | Year: 2012

The synthesis and characterization of microtubes of SiMoW 11 Keggin polyoxometalates containing either an Mo(V) or Mo(VI) atom is reported. The introduction of a Mo atom into the Keggin-type tungstosilicate microtubes endows them with new properties. The Mo-substituted microtubes may exert both W and Mo functionalities in electrocatalytic reactions and in the immobilization of noble metal nanoparticles. The degree of reduction of the Mo component in the SiMoW 11 microtubes is controllable simply by tuning the amount of reductant present in the mother liquor. Mo-substituted Keggin tungstosilicate microtubes in their reduced state are more stable than the all-tungsten Keggin tungstosilicate heteropoly blue microtubes. © 2012 American Chemical Society.

Qu X.,Monash University | Li X.,Inner Mongolia University | Zheng Y.,Northeast Normal University | Ren Y.,Florida State University | And 4 more authors.
American Journal of Pathology | Year: 2014

Transforming growth factor-β (TGF-β) promotes tissue fibrosis via receptor-mediated phosphorylation of the receptor-activated Smad2/3, together with Smad4. Of these, Smad3 plays a major profibrotic role in mouse models of tissue fibrosis. Transcriptional activity of the Smad3 protein is regulated by phosphorylation of residues in the C-terminal domain and the linker region. Herein, we examined the role of a novel phosphorylation site within the MH2 domain (T388) in the regulation of Smad3 activity. Confocal microscopy using an Smad3 phosphorylated T388-specific antibody identified phosphorylation of Smad3 T388 in myofibroblasts and tubular epithelial cells in human focal and segmental glomerulosclerosis and mouse models of unilateral ureteric obstruction and diabetic nephropathy, whereas phosphorylated T388 was largely absent in normal kidney. In vitro, TGF-β1 induced phosphorylation of Smad3 T388 in a biphasic pattern. A point mutation of T388/V in an Smad3 construct demonstrated that phosphorylation of T388 promotes Smad3 binding to Smad4 and CDK8, but was not necessary for nuclear translocation. Furthermore, T388 phosphorylation was required for TGF-β-induced collagen I gene promoter activity and extracellular matrix production in cultured fibroblasts. In conclusion, our study identifies phosphorylation of T388 in the Smad3 MH2 domain as an important mechanism that regulates the profibrotic TGF-β/Smad3 signaling pathway, which has direct relevance to human and experimental fibrotic kidney disease.

Yang Y.,Northeast Normal University | Yang J.,Northeast Normal University | Du P.,Northeast Normal University | Liu Y.-Y.,Northeast Normal University | And 2 more authors.
CrystEngComm | Year: 2014

Ten coordination polymers, namely, [Cu(HL)2] (1), [Cu(HL) 2]·2DMA (2) [Co2(L2)(DMF)]·DMF (3), [Co(L)(H2O)2]·DMF (4), [Co5(L) 4(OH)2(H2O)2]·4DMF (5), [Cd(L)(DMF)] (6), [Cd(L)(DMA)] (7), [Cd2(L)2(H 2O)4]·3H2O (8), [Mn2(L) 2(H2O)4]·3H2O (9) and [Mn(L)(DMF)2] (10), have been synthesized in mixed solvents under solvothermal conditions. Compound 1 reveals a one-dimensional (1D) chain, which is extended by hydrogen bonding interactions to generate a supramolecular layer. Compound 2 also shows a 1D chain, which is further linked by π-π and hydrogen bonding interactions to form a 3D supramolecular architecture. Compound 3 features a 3D (3,6)-connected net with (42·6)(4 4·62·88·10) topology. Compound 4 displays a 2D (3,4)-connected network with (4·6 2)(42·62·82) topology. These layers are linked by hydrogen bonds to form a 3D supramolecular framework. Compound 5 furnishes a 3D binodal (3,12)-connected net with (4 3)2(420·628·8 18) topology. Compound 6 possesses a 4-connected layer with (4 3·63) topology. Compound 7 reveals a 3D 4-connected framework with 4·65 topology. Compounds 8 and 9 are isostructural and exhibit similar 2D 63-hcb nets, which are further extended by hydrogen-bonding interactions into 3D supramolecular architectures. Compound 10 possesses a 2D 3-connected fes network. These complexes were characterized using X-ray single-crystal diffraction, elemental analysis, IR spectroscopy, PXRD and TGA. Moreover, the diffuse reflectivity spectra and the solid state photoluminescent properties of the ligand and compounds have also been studied at room temperature. This journal is © The Royal Society of Chemistry.

Liu W.Z.,Northeast Normal University | Xu H.Y.,Northeast Normal University | Zhang L.X.,Hong Kong University of Science and Technology | Zhang C.,Northeast Normal University | And 3 more authors.
Applied Physics Letters | Year: 2012

Localized surface plasmon (LSP)-enhanced ultraviolet light-emitting diodes were manufactured by introducing Ag nanoparticles and MgO spacer layer into n-ZnO/i-ZnO/p-GaN heterostructures. By optimizing the MgO thickness, which can suppress the undesired charge transfer and nonradiative Förster resonant energy transfer between Ag and ZnO, a 7-fold electroluminescence enhancement was achieved. Time-resolved and temperature-dependent photoluminescence measurements reveal that both spontaneous emission rate and internal quantum efficiency are increased as a result of coupling between ZnO excitons and Ag LSPs, and simple calculations, based on experimental data, also indicate that most of LSPs energy can be converted into the photon energy. © 2012 American Institute of Physics.

News Article | November 2, 2015

Although infected bats had lesions characteristic of the disease and similar to lesions seen in North American bats, the researchers do not know the extent to which Chinese bat species are affected by the disease. "We don't have historic population counts for bats in China, but there is no obvious evidence of the kind of population collapses that we've seen in North America," said Joseph Hoyt, a graduate student at the University of California, Santa Cruz, who led the study. Hoyt is first author of a paper on the new findings published November 2 in Emerging Infectious Diseases. Scientists have known since 2010 that the fungus that causes white-nose syndrome is present in Europe. As in China, there is no evidence of the fungus causing mass mortality in European bat populations. Bat species in areas where the fungus has existed for a long time may have evolved resistance to or tolerance of the disease, but may still suffer appreciable mortality, according to coauthor Marm Kilpatrick, associate professor of ecology and evolutionary biology at UC Santa Cruz. The new study expands the distribution of the fungus enormously and raises many interesting questions, Kilpatrick said. The overlapping ranges of the affected bat species in Europe and Asia suggest that the fungus may be widely distributed across all of northern Europe and Asia. "There are several European species that come into northern Asia, and some Asian species that cross over into Europe," Hoyt said. As a result of the new findings, Kilpatrick and Winifred Frick, who lead several research projects on white-nose syndrome at UC Santa Cruz, have received funding from the U.S. Fish and Wildlife Service to study the dynamics of the disease in China. "We've been studying disease dynamics in North America, and this gives us an opportunity to replicate that work in an endemic region where the pathogen has been for a long time," Frick said. The new findings have important implications for efforts to prevent further global spread of the disease, Hoyt noted. "People need to start thinking about decontamination after visiting caves in China," he said. Hoyt conducted the first sampling for the fungus in China in the summer of 2014, after receiving a National Science Foundation fellowship intended to promote research collaborations between U.S. graduate students and Chinese research institutions. He teamed up with researchers at Northeast Normal University in Changchun, China. After detecting the fungus at nine out of 12 sites, the researchers returned in winter of 2015 for additional sampling of cave environments and hibernating bats. The winter testing yielded positive results for the fungus in 75 percent of samples from three bat species. Explore further: Killer fungus spreads to endangered gray bats: US

Yang Y.,Northeast Normal University | Guo Y.,Northeast Normal University | Liu F.,Jilin University | Yuan X.,Northeast Normal University | And 3 more authors.
Applied Catalysis B: Environmental | Year: 2013

A series of silver deposited g-C3N4 (Ag/g-C3N4) plasmonic photocatalysts with Ag loading from 0.1 to 5wt% are prepared by thermal polymerization of urea precursor combined with the photodeposition method. The phase and chemical structure, electronic and optical properties as well as morphologies of Ag/g-C3N4 heterostructures are well-characterized. Subsequently, the photocatalytic activity of Ag/g-C3N4 is evaluated by the degradation of methyl orange (MO) and p-nitrophenol (PNP) under visible-light irradiation. The enhanced photocatalytic activity of Ag/g-C3N4 compared with g-C3N4 itself is obtained and explained in terms of the efficient visible-light utilization efficiency due to the SPR absorption of silver nanoparticles as well as fast generation, separation and transportation of the photogenerated carriers, evidenced by photoelectrochemical tests, photoluminescence measurements and free radical and hole scavenging experiments. Finally, the reusability of the catalyst is evaluated by five consecutive catalytic runs. © 2013 Elsevier B.V.

Chen D.-S.,Northeast Normal University | Sun L.-B.,Jilin University | Liang Z.-Q.,Jilin University | Shao K.-Z.,Northeast Normal University | And 3 more authors.
Crystal Growth and Design | Year: 2013

Six new coordination polymers, (Me2NH2)[In(L)] ·DMF (1), (Me2NH2)2[In 2(L)2]·(DMF)3·(H 2O)2 (2), (Me2NH2) 4[Cd2(L)2]·(DMF)2 (3), (Et2NH2)2[Cd(L)]·H2O (4), (Et2NH2)3[Cd2(L)2] ·(DEF)2·(H2O)4 (5), (Et 2NH2)3[Cd2(L)2] ·(EtNH2)2·(H2O)2 (6) have been prepared based on a newly designed flexible tetracarboxylate ligand of H4L {H4L = 5-[bis(3-carboxybenzyl)amino]isophthalic acid; DMF = N,N-dimethylformamide; DEF = N,N-diethylformamide}. Compounds 1-6 possess very similar two-dimensional framework structures with (4,4)-net topology. These compounds comprise two groups of conformational supramolecular isomers, owing to identical compositions of the frameworks but different conformations of ligands. It is worth noting that as much as seven pairs of stereoisomers of ligands have been found in these compounds, which demonstrated that the introduction of multiple single bonds has greatly expanded the flexibility of the ligand. The photoluminescent properties of compounds 1-6 have also been investigated where the emission of these supramolecular isomers are from blue to green. © 2013 American Chemical Society.

Irfan A.,King Khalid University | Al-Sehemi A.G.,King Khalid University | Muhammad S.,Osaka University | Zhang J.,Northeast Normal University
Australian Journal of Chemistry | Year: 2011

Theoretically calculated mobility has revealed that BDT is a hole transfer material, which is in good agreement with experimental investigations. The BDT, NHBDT, and OBDT are predicted to be hole transfer materials in the C2/c space group. Comparatively, hole mobility of BHBDT is 7 times while electron mobility is 20 times higher than the BDT. The packing effect for BDT and designed crystals was investigated by various space groups. Generally, mobility increases in BDT and its analogues by changing the packing from space group C2/c to space groups P1 or . In the designed ambipolar material, BHBDT hole mobility has been predicted 0.774 and 3.460cm2Vs-1 in space groups P1 and , which is 10 times and 48 times higher than BDT (0.075 and 0.072cm2Vs-1 in space groups P1 and ), respectively. Moreover, the BDT behaves as an electron transfer material by changing the packing from the C2/c space group to P1 and . © CSIRO 2011.

Min C.-G.,Jilin University | Ren A.-M.,Jilin University | Guo J.-F.,Northeast Normal University | Zou L.-Y.,Jilin University | And 2 more authors.
ChemPhysChem | Year: 2010

The question whether the emitter of yellow-green firefly bioluminescence is the enol or keto-constrained form of oxyluciferin (OxyLH2) still has no definitive answer from experiment or theory. In this study, Arg220, His247, adenosine monophosphate (AMP), Water324, Phe249, Gly343, and Ser349, which make the dominant contributions to color tuning of the fluorescence, are selected to simulate the luciferase (Luc) environment and thus elucidate the origin of firefly bioluminescence. Their respective and compositive effects on OxyLH2 are considered and the electronic absorption and emission spectra are investigated with B3LYP, B3PW91, and PBE1KCIS methods. Comparing the respective effects in the gas and aqueous phases revealed that the emission transition is prohibited in the gas phase but allowed in the aqueous phase. For the compositive effects, the optimized geometry shows that OxyLH2 exists in the keto(-1) form when Arg220, His247, AMP, Water324, Phe249, Gly343, and Ser349 are all included in the model. Furthermore, the emission maximum wavelength of keto(-1)+Arg+His+AMP+H2O+Phe+Gly+Ser is close to the experimental value (560 nm). We conclude that the keto(-1) form of OxyLH2 is a possible emitter which can produce yellow-green bioluminescence because of the compositive effects of Arg220, His247, AMP, Water324, Phe249, Gly343, and Ser349 in the luciferase environment. Moreover, AMP may be involved in enolization of the keto(-1) form of OxyLH2. Water324 is indispensable with respect to the environmental factors around luciferin (LH2).

Sun H.,Northeast Normal University | Zhang F.,Northeast Normal University | Wei H.,Jilin University | Yang B.,Jilin University
Journal of Materials Chemistry B | Year: 2013

Recently, researchers have paid much attention to the toxicity of QDs because of their rapidly increasing application in biomedicine. Recent investigations have indicated that QDs have influences on biological systems at the cellular, subcellular, and protein levels during the processes of imaging and therapeutic applications. The toxicity of QDs is related to their composition, surface functionality, size, shape, and charge, etc. among which composition and surface modification are two important elements. This feature article mainly concentrates on the latest developments in reducing QD toxicity by manipulating their composition and surface modification. Besides the cadmium-based QDs, the assessment of toxicity in vitro and in vivo for other QDs such as carbon dots, graphene QDs, silicon QDs, Ag2Se QDs, CuInS2@ZnS, InP QDs, hybrid QDs of carbon and CdSe@ZnS, etc., is generalized. Each kind of QD has its own advantages. Cadmium-based QDs have broad UV excitation, narrow emission and bright photoluminescence (PL), while cadmium-free ones present low toxicity. In fact, a lot of investigations show that the toxicity of QDs is dose dependent, whatever the composition. Consequently, surface modification becomes very important to reduce toxicity and simultaneously impart biocompatibility, stability, and specificity to QDs. Therefore, the functionalization of QDs with inorganic shells (e.g., CdSe@ZnS, CdSe@SiO2), polymers, bio- or natural macromolecules is summarized. Future research work should concentrate on preparing novel QDs with appropriate surface modification and investigating the long-term influence of QDs on absorption, distribution, metabolism, and elimination in vivo, especially for cadmium-free QDs such as carbon-based QDs, Ag2Se QDs, CuInS 2@ZnS QDs and InP QDs, etc. © 2013 The Royal Society of Chemistry.

Liu X.,Jilin University | Lin X.J.,Jilin University | Wang C.P.,Northeast Normal University | Yan K.K.,Jilin University | And 3 more authors.
Clinical Oncology | Year: 2014

Aims: To carry out a meta-analysis on the relationship between smoking and p53 gene mutation in lung cancer patients. Materials and methods: PubMed, Web of Science, ProQest and Medline were searched by using the key words: 'lung cancer or lung neoplasm or lung carcinoma', 'p53 mutation' and 'smoking'. According to the selection criteria, 15 articles were identified and methodologically analysed by stata 12.0 software package. Crude odds ratios with 95% confidence intervals calculated using the fixed-effects model were used to assess the strength of association between smoking and p53 mutation in lung cancer. Results: In total, 15 articles with 1770 lung cancer patients were identified; 69.6% of the patients were smokers, 30.4% were non-smokers. Overall, smokers with lung cancer had a 2.70-fold (95% confidence interval 2.04-3.59) higher risk for mutation than the non-smokers with lung cancer. In subgroup analyses, the increased risk of p53 mutation in smokers than in non-smokers was found in the non-small cell lung cancer (NSCLC) group (odds ratio=2.38, 95% confidence interval=1.71-3.32) and in the NSCLC and SCLC group (odds ratio=3.82, 95% confidence interval=2.19-6.69). Conclusions: This meta-analysis strongly suggests that p53 mutation is associated with smoking-induced lung cancer. Smokers with lung cancer had a higher risk for p53 mutation than non-smokers. © 2013 The Royal College of Radiologists.

Wang X.,Jilin University | Wang X.,Changchun University of Science and Technology | Tian H.,Jilin University | Cui X.,Jilin University | And 2 more authors.
Dalton Transactions | Year: 2014

We successfully synthesized mesoporous ZnxCd1-xS/ reduced graphene oxide (ZxCSG) hybrid materials as photocatalysts using a facile one-pot hydrothermal reaction, in which graphene oxide (GO) was easily reduced (RGO), and simultaneously ZnxCd1-xS (Z xCS) nanoparticles (NPs) with a mesoporous structure were uniformly dispersed on the RGO sheets. By well tuning the band gap from 3.42 to 2.21 eV by changing the molar ratio of Zn/Cd (or Zn content), ZxCSG with an optimal zinc content has been found to have a significant absorption in the visible light (VL) region. In addition, under VL irradiation (λ > 420 nm), ZxCSG also showed zinc content-dependent photocatalytic efficiencies for the degradation of methylene blue (MB). Our findings are that, among ZxCSG, Z0.4CSG displayed not only a superior photodegradation efficiency of MB (98%), but also good removal efficiency of total organic carbon (TOC) (67%). Furthermore, Z0.4CSG had a high photocatalytic stability, and could be used repeatedly. The enhanced photocatalytic activity for Z0.4CSG could be attributed to a synergistic effect between mesoporous ZxCS NPs and RGO, including the optimal band gap and the moderate conduction band position for ZxCS (compared to CdS), efficient separation and transfer ability of photogenerated electron/hole pairs in the presence of RGO sheets, and relatively high surface area for both mesoporous ZxCS NPs and RGO. This journal is © the Partner Organisations 2014.

Wang X.,Jilin University | Wang X.,Changchun University of Science and Technology | Tian H.,Jilin University | Yang Y.,Jilin University | And 4 more authors.
Journal of Alloys and Compounds | Year: 2012

Reduced graphene oxide/cadmium sulfide (RGO/CdS) hybrid material was synthesized by a one-step solvothermal method, wherein graphene oxide (GO) was a supporting material on which CdS nanoparticles were distributed homogeneously, and cadmium acetate (Cd(Ac) 2·2H 2O) was used as the CdS precursor. The supporting material RGO for CdS nanoparticles effectively enhanced their photocatalytic activities for the photodegradation of methylene blue in the aqueous solution. The optimum weight ratio of the GO to CdS in the hybrid material was 5.0%, which exhibited an excellent photodegradation efficiency (94%) and a better removal efficiency of total organic carbon (TOC) (57%), about 2.5 times and 5.1 times higher than that of pure CdS nanoparticles, respectively, under visible light (VL) irradiation. This improved photodegradation efficiency could be attributed to the increased adsorbability for methylene blue molecules, light absorption levels located in visible region, high charge transfer and separation ability, due to the introduction of a two-dimensional RGO network. © 2012 Elsevier B.V.

Zhou D.,Jilin University | Lin M.,Jilin University | Liu X.,Jilin University | Li J.,Jilin University | And 5 more authors.
ACS Nano | Year: 2013

We report a ligand decoration strategy to enlarge the lattice dilation of quantum dots (QDs), which greatly enhances the characteristic sensitivity of a QD-based thermometer. Upon a multiple covalent linkage of macrocyclic compounds with QDs, for example, thiolated cyclodextrin (CD) and CdTe, the conformation-related torsional force of CD is conducted to the inner lattice of CdTe under altered temperature. The combination of the lattice expansion/contraction of CdTe and the stress from CD conformation change greatly enhances the shifts of both UV-vis absorption and photoluminescence (PL) spectra, thus improving the temperature sensitivity. As an example, β-CD-decorated CdTe QDs exhibit the 0.28 nm shift of the spectra per degree centigrade (0.28 nm/ C), 2.4-fold higher than those of monothiol-ligand- decorated QDs. © 2013 American Chemical Society.

Liu H.,Jilin University | Liu L.,Jilin University | Zhang H.,Northeast Normal University
Pattern Recognition | Year: 2010

Cancer diagnosis is an important emerging clinical application of microarray data. Its accurate prediction to the type or size of tumors relies on adopting powerful and reliable classification models, so as to patients can be provided with better treatment or response to therapy. However, the high dimensionality of microarray data may bring some disadvantages, such as over-fitting, poor performance and low efficiency, to traditional classification models. Thus, one of the challenging tasks in cancer diagnosis is how to identify salient expression genes from thousands of genes in microarray data that can directly contribute to the phenotype or symptom of disease. In this paper, we propose a new ensemble gene selection method (EGS) to choose multiple gene subsets for classification purpose, where the significant degree of gene is measured by conditional mutual information or its normalized form. After different gene subsets have been obtained by setting different starting points of the search procedure, they will be used to train multiple base classifiers and then aggregated into a consensus classifier by the manner of majority voting. The proposed method is compared with five popular gene selection methods on six public microarray datasets and the comparison results show that our method works well. © 2010 Elsevier Ltd. All rights reserved.

Wang H.,Northeast Normal University | Jiang P.,Jilin University | Bo X.,Northeast Normal University | Guo L.,Northeast Normal University
Electrochimica Acta | Year: 2012

Mesoporous carbon nanofibers (M-CNF) were synthesized using a self-templating strategy and a solution growth process. An M-CNF modified glassy carbon electrode (M-CNF/GCE) was fabricated, and its electrocatalytic performance was investigated for the first time using dopamine (DA), ascorbic acid (AA) and uric acid (UA) as probes. The M-CNF/GCE exhibited satisfactory electrocatalytic activity by significantly decreasing the oxidation potentials and increasing the peak currents in the oxidation of DA, AA and UA when compared with those obtained using the GCE. More importantly, the M-CNF/GCE afforded the simultaneous detection of DA, AA and UA at a physiological pH of 7.4 with a wide linear response and high sensitivity. Moreover, under amperometric conditions, the M-CNF/GCE was capable of detecting DA, AA and UA with low detection limits. Furthermore, the universality of the electrocatalytic capability of the M-CNF was confirmed by its superior electrocatalytic oxidation of purines, such as guanine (G), adenine (A), xanthine (XA) and hypoxanthine (HX). © 2012 Elsevier Ltd. All rights reserved.

Han X.-B.,Northeast Normal University | Zhang Z.-M.,Northeast Normal University | Zhang Z.-M.,University of Chicago | Zhang Z.-M.,Xiamen University | And 7 more authors.
Journal of the American Chemical Society | Year: 2014

A series of all-inorganic, abundant-metal-based, high-nuclearity cobalt-phosphate (Co-Pi) molecular catalysts [{Co4(OH) 3(PO4)}4(SiW9O34) 4]32- (1), [{Co4(OH)3(PO 4)}4(GeW9O34)4] 32- (2), [{Co4(OH)3(PO4)} 4(PW9O34)4]28- (3), and [{Co4(OH)3(PO4)}4(AsW 9O34)4]28- (4) were synthesized and shown to be highly effective at photocatalytic water oxidation. The {Co 16(PO4)4} cluster contains a Co 4O4 cubane which is structurally analogous to the [Mn 3CaO4] core of the oxygen-evolving complex (OEC) in photosystem II (PSII). Compounds 1-4 were shown to be the first POM-based Co-Pi-cluster molecular catalysts for visible light-driven water oxidation, thus serving as a functional model of the OEC in PSII. The systematic synthesis of four isostructural analogues allowed for investigating the influence of different heteroatoms in the POM ligands on the photocatalytic activities of these Co-Pi cluster WOCs. Further, the POM-based photocatalysts readily recrystallized from the photocatalytic reaction systems with the polyoxoanion structures unchanged, which together with the laser flash photolysis, dynamic light-scattering, 31P NMR, UV-vis absorption, POM extraction, and ICP-MS analysis results collectively confirmed that compounds 1-4 maintain their structural integrity under the photocatalytic conditions. This study provides not only a valuable molecular model of the "Co-Pi" catalysts with a well-defined structure but also an unprecedented opportunity to fine-tune high-nuclearity POM clusters for visible light-driven water splitting. © 2014 American Chemical Society.

Tang Q.,Northeast Normal University | Liu Y.,Northeast Normal University | Liu S.,Northeast Normal University | He D.,Northeast Normal University | And 6 more authors.
Journal of the American Chemical Society | Year: 2014

A lanthanide metal-organic framework (MOF) compound of the formulation [Eu2(CO3)(ox)2(H2O) 2]·4H2O (1, ox = oxalate) was prepared by hydrothermal synthesis with its structure determined crystallographically. Temperature-dependent but humidity-independent high proton conduction was observed with a maximum of 2.08 × 10-3 S cm-1 achieved at 150 °C, well above the normal boiling point of water. Results from detailed structural analyses, comparative measurements of conductivities using regular and deuterated samples, anisotropic conductivity measurements using a single-crystal sample, and variable-temperature photoluminescence studies collectively establish that the protons furnished by the Eu(III)-bound and activated aqua ligands are the charge carriers and that the transport of proton is mediated along the crystallographic a-axis by ordered hydrogen-bonded arrays involving both aqua ligands and adjacent oxalate groups in the channels of the open framework. Proton conduction was enhanced with the increase of temperature from room temperature to about 150 °C, which can be rationalized in terms of thermal activation of the aqua ligands and the facilitated transport between aqua and adjacent oxalate ligands. A complete thermal loss of the aqua ligands occurred at about 160 °C, resulting in the disintegration of the hydrogen-bonded pathway for proton transport and a precipitous drop in conductivity. However, the structural integrity of the MOF was maintained up to 350 °C, and upon rehydration, the original structure with the hydrogen-bonded arrays was restored, and so was its high proton-conduction ability. © 2014 American Chemical Society.

Li X.,Northeast Normal University | Yin M.,Northeast Normal University | Yin M.,Jilin University
Progress In Electromagnetics Research B | Year: 2011

The reconfigurable design problem is to find the element that will result in a sector pattern main beam with side lobes. The same excitation amplitudes apply to the array with zero-phase that should be in a high directivity, low side lobe pencil shaped main beam. Multi-beam antenna arrays have important applications in communications and radar. This paper presents a new method of designing a reconfigurable antenna array with quantized phase excitations using a new evolutionary algorithm called differential evolution (DE). In order to reduce the effect of mutual coupling among the antenna-array elements, the dynamic range ratio is minimized. Additionally, compared with the continuous realization and subsequent quantization, experimental results indicate better performance of the discrete realization of the phase-excitation value of the proposed algorithm.

Du P.,Northeast Normal University | Yang Y.,Northeast Normal University | Yang J.,Northeast Normal University | Liu B.-K.,Jilin University | Ma J.-F.,Northeast Normal University
Dalton Transactions | Year: 2013

Four novel metal-organic frameworks (MOFs) based on high-nuclear metal carboxylate clusters, namely, [Zn4(L)2(μ3- OH)2(H2O)1.5]·2H2O (1), [Zn5Na(L)2(μ3-OH)4(CH 3CH2O)(H2O)2] (2), [Cd 4(L)2(BIME)0.5(μ3-OH) 2(H2O)1.5]·2H2O (3), and [Zn4(L)2(BET)0.5(μ3-OH) 2(H2O)] (4), where H3L = (3,5-dicarboxyl- phenyl)-(4-(2′-carboxyl-phenyl)-benzyl)ether, BET = 1,1′-(2′- oxybis(ethane-2,1-diyl))bis(1,2,4-triazol-1-yl), BIME = 1,2-bis(imidazol-1-yl) ethane, have been synthesized under hydrothermal conditions. In 1, each planar octanuclear zinc cluster [Zn8(μ3-OH) 8(CO2)12(H2O)3] is linked by twelve L anions to give an unusual (3,12)-connected framework with (4 3)2(420·628·8 18) topology. In 2, dodecanuclear heterometallic clusters [Zn 10Na2(μ3-OH)8(CO 2)12(CH3CH2O)2(H 2O)4] are surrounded by twelve L anions to form a (3,12)-connected net with the same topology as 1. However, 3 exhibits a rare (3,14)-connected (43)(324)(34·4 20·514·634·7 11·88) net based on octanuclear cadmium cluster [Cd8(BIME)2(μ3-OH)4(CO 2)12(H2O)4]·2H2O as a 14-connected node and H3L as a 3-connected node. In 4, each octanuclear zinc cluster [Zn8(BET)2(μ3-OH) 4(CO2)12(H2O)2] is linked by twelve L anions to furnish a (3,14)-connected net with the same topology as 3. The optical energy gaps and photoluminescence were investigated for the compounds. Moreover, compounds 1-4 exhibit good photocatalytic activities for degradation of methylene blue (MB) under UV irradiation and show good stability towards UV photocatalysis. In addition, 1 and 4 display a photocurrent density under several on-off cycles of illumination. © The Royal Society of Chemistry 2013.

Sun L.,Jilin University | Xing H.,Northeast Normal University | Xu J.,Jilin University | Liang Z.,Jilin University | And 2 more authors.
Dalton Transactions | Year: 2013

A novel metal-organic framework [Cd3(CPEIP)2(DMF) 3]·solvent (1) based on a neutral non-oxo triangular [Cd 3(COO)6] secondary building unit (SBU), was synthesized under solvothermal conditions by using a rigid unsymmetrical tricarboxylate ligand 5-((4-carboxyphenyl)ethynyl)isophthalic acid (H3CPEIP). Single-crystal X-ray diffraction analysis reveals that compound 1 crystallizes in the monoclinic space group C2/c. The crystal structure exhibits a rare (3,3,6)-connected three-dimensional (3-D) framework with vertex symbol of (42.6)(43)(45.64.86). The incorporation of CPEIP3+ into 1 gives rise to high luminescence in solid state. The emission of micrometer-sized compound 1 (1′) dispersed in ethanol could be quenched efficiently by picric acid (PA), indicating that this compound could be utilized as a chemosensor for detection of aromatic explosives. © 2013 The Royal Society of Chemistry.

Jiang Y.,Northeast Normal University | Liu S.,Northeast Normal University | Zhang J.,Jilin University | Wu L.,Jilin University
Dalton Transactions | Year: 2013

A series of composition analogous polyoxometalate-based ionic complexes are synthesized and studied, with a focus on the correlation between their mesomorphic behavior and their chemical structure. Generally, these polarizable rigid polyoxoanion clusters decorated with hydrophobic flexible alkyl chains have demonstrated a propensity to form thermotropic liquid-crystalline (LC) phases. Characterized by differential scanning calorimetry (DSC), polarized optical microscopy (PM), and X-ray diffraction (XRD), two of the four investigated complexes tend to form thermodynamically stable mesophases. Longer alkyl chains have been found to form mesophases, and the alkyl chain length of the quaternary ammonium cations influences both the occurrence and type of mesophase exhibited. This journal is © The Royal Society of Chemistry 2013.

Zhou L.,Northeast Normal University | Zhou L.,Changchun University | Fan M.,Northeast Normal University
Nonlinear Analysis: Real World Applications | Year: 2012

The dynamics of an SIR epidemic model is explored in this paper in order to understand how the limited medical resources and their supply efficiency affect the transmission of infectious diseases. The study reveals that, with varying amount of medical resources and their supply efficiency, the target model admits both backward bifurcation and Hopf bifurcation. Sufficient criteria are established for the existence of backward bifurcation, the existence, the stability and the direction of Hopf bifurcation. The mechanism of backward bifurcation and its implication for the control of the infectious disease are also explored. Numerical simulations are presented to support and complement the theoretical findings. © 2011 Elsevier Ltd. All rights reserved.

Chen X.-K.,Jilin University | Guo J.-F.,Northeast Normal University | Zou L.-Y.,Jilin University | Ren A.-M.,Jilin University | Fan J.-X.,Jilin University
Journal of Physical Chemistry C | Year: 2011

The effects of the pyrazine ring on the geometrical and electronic structures, molecular stacking motifs, carrier injection, and transport properties as well as electronic band structures for some typical molecules with pyrazines (such as tetracene, pentacene, and π-extended tetrathiafulvalene derivatives) were theoretically investigated by quantum chemical methods. The introduction of pyrazine does not affect the molecular planarity and in the meantime largely decreases the energies of the highest occupied molecular orbitals and the lowest unoccupied molecular orbitals and hence improves their stability in air and ability of electron injection. More important, it is very helpful for prompting the molecular π-stacking. Small electron reorganization energies and large electronic coupling originated from their dense π-stacking give rise to their excellent electron transport properties, which makes them become a class of promising candidates for excellent n-type organic field-effect transistor (OFET) materials. So introducing pyrazine is an effective approach to obtain the excellent n-type OFET materials. © 2011 American Chemical Society.

Liu Y.,Northeast Normal University | Liu Y.,University of California at Los Angeles | Feng J.,Northeast Normal University | Metzner W.,University of California at Los Angeles | Metzner W.,Doshisha University
PLoS ONE | Year: 2013

Auditory feedback from the animal's own voice is essential during bat echolocation: to optimize signal detection, bats continuously adjust various call parameters in response to changing echo signals. Auditory feedback seems also necessary for controlling many bat communication calls, although it remains unclear how auditory feedback control differs in echolocation and communication. We tackled this question by analyzing echolocation and communication in greater horseshoe bats, whose echolocation pulses are dominated by a constant frequency component that matches the frequency range they hear best. To maintain echoes within this "auditory fovea", horseshoe bats constantly adjust their echolocation call frequency depending on the frequency of the returning echo signal. This Doppler-shift compensation (DSC) behavior represents one of the most precise forms of sensory-motor feedback known. We examined the variability of echolocation pulses emitted at rest (resting frequencies, RFs) and one type of communication signal which resembles an echolocation pulse but is much shorter (short constant frequency communication calls, SCFs) and produced only during social interactions. We found that while RFs varied from day to day, corroborating earlier studies in other constant frequency bats, SCF-frequencies remained unchanged. In addition, RFs overlapped for some bats whereas SCF-frequencies were always distinctly different. This indicates that auditory feedback during echolocation changed with varying RFs but remained constant or may have been absent during emission of SCF calls for communication. This fundamentally different feedback mechanism for echolocation and communication may have enabled these bats to use SCF calls for individual recognition whereas they adjusted RF calls to accommodate the daily shifts of their auditory fovea. © 2013 Liu et al.

Liu H.,Jilin University | Liu L.,Jilin University | Zhang H.,Northeast Normal University
Journal of Biomedical Informatics | Year: 2010

Selecting relevant and discriminative genes for sample classification is a common and critical task in gene expression analysis (e.g. disease diagnostic). It is desirable that gene selection can improve classification performance of learning algorithm effectively. In general, for most gene selection methods widely used in reality, an individual gene subset will be chosen according to its discriminative power. One of deficiencies of individual gene subset is that its contribution to classification purpose is limited. This issue can be alleviated by ensemble gene selection based on random selection to some extend. However, the random one requires an unnecessary large number of candidate gene subsets and its reliability is a problem. In this study, we propose a new ensemble method, called ensemble gene selection by grouping (EGSG), to select multiple gene subsets for the classification purpose. Rather than selecting randomly, our method chooses salient gene subsets from microarray data by virtue of information theory and approximate Markov blanket. The effectiveness and accuracy of our method is validated by experiments on five publicly available microarray data sets. The experimental results show that our ensemble gene selection method has comparable classification performance to other gene selection methods, and is more stable than the random one. © 2009 Elsevier Inc. All rights reserved.

Chen X.-K.,Jilin University | Zou L.-Y.,Jilin University | Guo J.-F.,Northeast Normal University | Ren A.-M.,Jilin University
Journal of Materials Chemistry | Year: 2012

The aromatic diimides are among the most promising and versatile candidates for organic optoelectronic materials due to their commercial availability, low cost, excellent optical and electric performance, such as naphthalene, anthracene and perylene diimides. But, so far, the problem is not clarified - is a five- or six-membered imide ring more helpful for n-type organic semiconductor materials? The work investigated in detail and compared various properties for molecules with a five-/six-membered imide ring from the following aspects: (1) molecular stability, reaction activity, geometries, frontier molecular orbitals as well as oxidation and reduction abilities at the single-molecule level; (2) the variation of transfer integrals at the various molecular stacking motifs; (3) the estimate of carrier mobility and its anisotropy for the actual molecule crystals. The results indicate that molecules with a six-membered imide ring should be more suitable for n-type organic semiconductor materials. This journal is © The Royal Society of Chemistry 2012.

Yan K.,Jilin University | Xu X.,Jilin University | Liu X.,Jilin University | Wang X.,University of Manitoba | And 2 more authors.
Pediatric Blood and Cancer | Year: 2015

Background: Although genetic and environmental factors are considered to be the main causes of acute lymphoblastic leukemia, the associations between maternal factors during pregnancy and the childhood ALL is still unclear. Procedure: In this study, meta-analysis was used. Medline, PubMed, and Web of Science were searched. The result was assessed based on pooled odds ratios (ORs) with 95% confidence intervals (CIs). Results: The pooled ORs showed that there were associations between childhood ALL and the birth order (The first vs others, OR=1.08, 95%CI=1.00-1.16), the education of pregnant woman (>high school vs ≤high school, OR=0.82, 95%CI=0.77-0.86), smoking (Ever vs never, OR=1.10, 95%CI=1.02-1.19). Conclusions: Our meta-analysis showed that there were important associations between childhood ALL and the birth order, the education of pregnant woman, smoking. Pediatr Blood Cancer 2015;62:1162-1170. © 2015 Wiley Periodicals, Inc.

Jin G.,Northeast Normal University | Wei H.-T.,Jilin University | Na T.-Y.,Jilin University | Sun H.-Z.,Northeast Normal University | And 2 more authors.
ACS Applied Materials and Interfaces | Year: 2014

Aqueous-processed solar cells have evolved into a new generation of promising and renewable energy materials due to their excellent optical, electrical, and low-cost properties. In this work, Cd0.75Hg 0.25Te colloid quantum dots (CQDs) were incorporated into a water-soluble conjugated polymer with broad absorption and high charge-carrier-mobility (5 × 10-4 cm2 V-1 s-1) to obtain a composite with an absorption spectrum ranging from 300 to 1200 nm. The matched energy level between polymer and CQDs ensured the effective electron transfer, while the interpenetrating network structure formed via heat treatment guaranteed the quick electron transport. Moreover, the formation process of the interpenetrating network was systematically monitored by using AFM and TEM instruments and further confirmed through the measurement of charge-carrier-mobility of the active layers. In combination with the surface modification of a single Cd0.75Hg0.25Te layer, this aqueous-processed solar cell showed excellent photovoltaic response and the power conversion efficiency (PCE) reached 2.7% under AM 1.5 G illumination (100 mW cm-2). Especially, the contribution of the Herschel infrared region (780-1100 nm) to the photocurrent was as high as 15.04%. This device showed the highest PCE among organic-inorganic hybrid solar cells (HSCs) based on CdxHg1-xTe CQDs and the highest near infrared (NIR) contribution among aqueous-processed HSCs, indicating the enormous potential of taking advantage of NIR energy in a solar spectrum and a promising application in solar cells especially used in cloudy weather. © 2014 American Chemical Society.

Tang X.-D.,Capital Normal University | Tang X.-D.,Northeast Normal University | Liao Y.,Capital Normal University | Liao Y.,Northeast Normal University | And 3 more authors.
Journal of Materials Chemistry | Year: 2012

The fascinating effect of dehydrogenation on the charge transport properties of N-heteropentacene (N-PEN) derivatives was systematically investigated through Marcus electron transfer theory coupled with normal mode analysis distributed into internal coordinates for the reorganization energies and the random walk simulation of charge diffusion constants. The calculated results show that dehydrogenation of N-PEN derivatives will markedly increase the electron transfer integrals and simultaneously decrease the energy levels of the lowest unoccupied molecular orbitals (LUMOs) as well as the electron reorganization energies (λ e), which provides a three-in-one advantage for improving the electron transfer. The lower LUMO levels detected in the dehydrogenated N-PENs compared to the hydrogenated ones can be inferred from their electronic structures, that is, the latter are formally antiaromatic, having 2 more electrons than the former (aromatic 22 π electron species). The reduced reorganization energies of the dehydrogenated N-PENs could be intimately connected to the bonding nature of the nitrogen atoms in the LUMOs. Upon the dehydrogenation of N-PENs, the effective intermolecular π-overlap in the LUMOs of the nearest-neighboring molecules is enhanced, and then increased the electron transfer integrals. Interestingly, the transport parameters evaluated from the band and hopping models both indicate intrinsic mobility for electron transfer in the dehydrogenated N-PENs. The dehydrogenation of N-PEN derivatives can, thus, be a useful strategy for preparing n-type organic semiconductors. © 2012 The Royal Society of Chemistry.

Wang X.,Northeast Normal University | Navasca C.,University of Alabama at Birmingham
Proceedings of the IEEE International Conference on Computer Vision | Year: 2016

In this paper, we propose a novel framework for finding low rank approximation of a given tensor. This framework is based on the adaptive lasso with coefficient weights for sparse computation in tensor rank detection. We also provide an algorithm for solving the adaptive lasso model problem for tensor approximation. In a special case, the convergence of the algorithm and the probabilistic consistency of the sparsity have been addressed [15] when each weight equals to one. The method is applied to background extraction and video compression problems. © 2015 IEEE.

Zhang J.,Northeast Normal University | Liang Q.,Northeast Normal University | Lei Y.,Northeast Normal University | Yao M.,Jilin University | And 8 more authors.
Cancer Research | Year: 2012

Epithelial-mesenchymal transition (EMT) is a developmental program, which is associated with breast cancer progression and metastasis. Here, we report that ectopic overexpression of SOX4 in immortalized human mammary epithelial cells is sufficient for acquisition of mesenchymal traits, enhanced cell migration, and invasion, along with epithelial stem cell properties defined by the presence of a CD44high/CD24low cell subpopulation. SOX4 positively regulated expression of known EMT inducers, also activating the TGF-β pathway to contribute to EMT. SOX4 itself was induced by TGF-β in mammary epithelial cells and was required for TGF-β-induced EMT. Murine xenograft experiments showed that SOX4 cooperated with oncogenic Ras to promote tumorigenesis in vivo. Finally, in clinical specimens of human breast cancer, we found that SOX4 was abnormally overexpressed and correlated with the triple-negative breast cancer subtype (ER-/PR-/HER2 -). Our findings define an important function for SOX4 in the progression of breast cancer by orchestrating EMT, and they implicate this gene product as a marker of poor prognosis in this disease. ©2012 AACR.

Yang S.-N.,Karolinska Institutet | Yang S.-N.,Northeast Normal University | Shi Y.,Karolinska Institutet | Yang G.,Karolinska Institutet | And 4 more authors.
Cellular and Molecular Life Sciences | Year: 2014

The function and survival of pancreatic β cells critically rely on complex electrical signaling systems composed of a series of ionic events, namely fluxes of K+, Na+, Ca2+ and Cl- across the β cell membranes. These electrical signaling systems not only sense events occurring in the extracellular space and intracellular milieu of pancreatic islet cells, but also control different β cell activities, most notably glucose-stimulated insulin secretion. Three major ion fluxes including K+ efflux through ATP-sensitive K+ (KATP) channels, the voltage-gated Ca2+ (CaV) channel-mediated Ca2+ influx and K+ efflux through voltage-gated K+ (KV) channels operate in the β cell. These ion fluxes set the resting membrane potential and the shape, rate and pattern of firing of action potentials under different metabolic conditions. The KATP channel-mediated K+ efflux determines the resting membrane potential and keeps the excitability of the β cell at low levels. Ca2+ influx through CaV1 channels, a major type of β cell CaV channels, causes the upstroke or depolarization phase of the action potential and regulates a wide range of β cell functions including the most elementary β cell function, insulin secretion. K+ efflux mediated by KV2.1 delayed rectifier K+ channels, a predominant form of β cell KV channels, brings about the downstroke or repolarization phase of the action potential, which acts as a brake for insulin secretion owing to shutting down the CaV channel-mediated Ca2+ entry. These three ion channel-mediated ion fluxes are the most important ionic events in β cell signaling. This review concisely discusses various ionic mechanisms in β cell signaling and highlights KATP channel-, CaV1 channel- and KV2.1 channel-mediated ion fluxes. © 2014 Springer Basel.

Wang C.L.,Northeast Normal University | Kang Z.H.,Jilin University | Tian S.C.,Jilin University | Wu J.H.,Jilin University
Optics Express | Year: 2012

We demonstrate coherent control of spontaneous emission from an indirectly coupled transition in a microwave driven four-level atomic system. The transition of concern is not directly coupled by any laser fields, while the ground state is coupled to another ground state by a microwave field. We show that the coupling of the microwave field produces interesting features such as double narrow lines in the emission spectrum. The heights, widths and positions of the emission peaks can be controlled by modifying the Rabi frequency and detuning of the microwave field. We discuss the spectra in the dressed states basis. © 2012 Optical Society of America.

Muhammad S.,Northeast Normal University | Muhammad S.,Osaka University | Xu H.-L.,Northeast Normal University | Zhong R.-L.,Northeast Normal University | And 3 more authors.
Journal of Materials Chemistry C | Year: 2013

Nonlinear optical (NLO) materials are the smartest materials of the era, and have the ability to generate new electromagnetic fields with changed frequencies, phases, and other physical properties. Recently, many cutting edge research reports have been focused on NLO materials especially on those which are composed of sp2 hybridized carbon nanostructures. As the carbon nanostructures are composed of abundant π-electrons and have significant delocalization, these are potential candidates for modern NLO materials. Generally, sp2 hybridized carbon nanostructures can be divided into zero-dimensional fullerenes, one-dimensional nanotubes and two-dimensional graphene nanoribbons and quantum dots etc. These dimensionally different carbon nanomaterials are promising candidates for a wide range of applications in next-generation nanotechnologies. In present feature article, we first briefly explain a theoretical structure-NLO property relationship based on perturbation theory and then elucidate the crucial factors to control the NLO responses. We put together the different random investigations of sp2 hybridized carbon nanostructures for NLO application by highlighting the importance of their several structural designs to tune NLO amplitudes. Furthermore, we make a comparative and updated analysis of the NLO properties of dimensionally different sp2 hybridized carbon nanomaterials i.e. fullerenes, carbon nanotubes, and graphene nanoribbons and quantum dots. Finally, we make a brief discussion about different aspects and opportunities to use the sp2 hybridized carbon nanomaterials as high performance NLO materials of the future. This review is a focused perspective based on different updated quantum chemical investigations about fullerenes, nanotubes and graphene nanoribbons and quantum dots for their possible use in nonlinear optical applications. This journal is © The Royal Society of Chemistry 2013.

Fu Z.,Jilin University | Yang F.,Northeast Normal University
Information Processing Letters | Year: 2014

An essential problem in the design of holographic algorithms is to decide whether the required signatures can be realized under a suitable basis transformation (SRP). For holographic algorithms with matchgates on domain size 2, [1,2,4,5] have built a systematical theory. In this paper, we reduce SRP on domain size k≥3 to SRP on domain size 2 for holographic algorithms with matchgates on bases of rank 2. Furthermore, we generalize the collapse theorem of [3] to domain size k≥3. © 2014 Elsevier B.V.

Yang G.Z.,Sun Yat Sen University | Song H.W.,Sun Yat Sen University | Cui H.,Sun Yat Sen University | Liu Y.C.,Northeast Normal University | Wang C.X.,Sun Yat Sen University
Nano Energy | Year: 2013

Ultrafast rechargeable lithium-ion batteries made from low-cost and abundant electrode materials would satisfy the increasing demands for energy storage worldwide. Herein, we demonstrate a large-scale hierarchical bottom-up assembly route for the formation of lithium-ion battery anode with excellent electrochemical properties by creating composites based on embedding ZnO nanoparticles into nanocarbon matrix which uniformly dispersed on the outer and inner surfaces of a porous creased carbon bubble host, which serves to hold them tightly by the pores and creases during battery operation and sandwich them between rapid ion and electron transport pathways. We successfully increase the charging and discharging rates by nearly 300-fold over the highest rate yet reported while attaining high power density and energy density which represents the best performance for long-cycle ZnO anode so far.© 2013 Elsevier Ltd.

Zheng A.,Xiamen University | Xu J.,Northeast Normal University
Advanced Materials Research | Year: 2012

2,6-dinitrotoluene (2,6-DNT) is the preferential toxicants stipulated by OECD and EPA of USA. The present study was conducted to determine the effect of 2,6-DNT chemical on acute toxicity and subacute toxicity in common carp (Cyprinus carpio). The 24h, 48h, 72h and 96h LC50 values of common carp by 2,6-DNT were 1.137±0.023mg/L, 0.830±0.024mg/L, 0.661±0.019mg/L and 0.479±0.020mg/L, respectively. The subacute experiment shows that C. carpio are rarely affected by 0.0251mg/L 2,6-DNT, but significantly affected by 0.0398, 0.0631, 0.0794mg/L 2,6-DNT in contrast to the controlled sample (p < 0.05). The accumulative rate (K) is 1.25 for C. carpio exposed to 2,6-DNT. This shows that there are significant accumulative actions in common carp. Among 0.024-0.420mg/L 2,6-DNT, the higher the 2,6-DNT concentration, the stronger the Na +/K +-ATPase are inhibited. The IC50 values (the concentration of 2,6-DNT required to effect 50% inhibition of Na +/K +-ATPase) following gill, kidney and liver on C. carpio are 0.18mg/L, 0.24mg/L and 0.23 mg/L, respectively. The toxicity order of the observed IC50 values of 2,6-DNT to C. carpio tissues has been found as following: gill> liver > kidney. © (2012) Trans Tech Publications, Switzerland.

Sui J.,Tsinghua University | Sui J.,University of Oxford | Liu M.,Northeast Normal University | Mevorach C.,University of Birmingham | Humphreys G.W.,University of Oxford
Cerebral Cortex | Year: 2013

Perceptual learning is associated with experience-based changes in stimulus salience. Here, we use a novel procedure to show that learning a new association between a self-label and a neutral stimulus produces fast alterations in social salience measured by interference when targets associated with other people have to be selected in the presence of self-associated distractors. Participants associated neutral shapes with either themselves or a friend, over a short run of training trials. Subsequently, the shapes had to be identified in hierarchical (global-local) forms. The data show that giving a shape greater personal significance by associating it with the self had effects on visual selection equivalent to altering perceptual salience. Similar to previously observed effects linked to when perceptually salient distractors are ignored, effects of a self-associated distractor also increased activation in the left intraparietal cortex sulcus. The results show that self-associations to sensory stimuli rapidly modulate neural responses in a manner similar to changes in perceptual saliency. The self-association procedure provides a new way to understand how personal significance affects behavior. © The Author 2013. Published by Oxford University Press.

Wang C.,Jilin University | Li Y.,Northeast Normal University
Journal of Information and Computational Science | Year: 2013

Detecting communities from complex networks has been the focus of many recent efforts on complex networks. In complex networks it is common for each node to belong to several communities, implying a highly overlapping community structure. We introduce a new algorithm for overlapping community finding, the algorithm first finds some seeds and expands these seeds into a community. We perform the algorithm on different data to demonstrate that performance of our algorithm is robust across diverse parameters. The algorithm is compared with current representative algorithms in community mining. Experimental results show the feasibility and validity of our algorithm. We show that our algorithm is highly effective at discovering community structure in different types of complex networks. Copyright © 2013 Binary Information Press.

Zhong R.-L.,Northeast Normal University | Xu H.-L.,Northeast Normal University | Su Z.-M.,Northeast Normal University | Li Z.-R.,Jilin University | And 2 more authors.
ChemPhysChem | Year: 2012

Much effort has been devoted to investigating the unusual properties of the π electrons in Möbius cyclacenes, which are localized in a special region. However, the localized π electrons are a disadvantage for applications in optoelectronics, because intramolecular charge transfer is limited. This raises the question of how the intramolecular charge transfer of a Möbius cyclacene with clearly localized π electrons can be enhanced. To this end, [8]Möbius cyclacene ([8]MC) is used as a conjugated bridge in a donor-π-conjugated bridge-acceptor (D-π-A) system, and NH 2-6-[8]MC-10-NO 2 exhibits a fascinating spiral charge-transfer transition character that results in a significant difference in dipole moments Δμ between the ground state and the crucial excited state. The Δμ value of 6.832 D for NH 2-6-[8]MC-10-NO 2 is clearly larger than that of 0.209 D for [8]MC. Correspondingly, the first hyperpolarizability of NH 2-6-[8]MC-10-NO 2 of 12 467 a.u. is dramatically larger than that of 261 a.u. for [8]MC. Thus, constructing a D-π-A framework is an effective strategy to induce greater spiral intramolecular charge transfer in MC although the π electrons are localized in a special region. This new insight into the properties of π electrons in Möbius cyclacenes may provide valuable information for their applications in optoelectronics. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wang X.,Jilin University | Wu J.-H.,Northeast Normal University
Optics Express | Year: 2016

We study an ensemble of ultracold atoms trapped in the onedimensional optical lattices under the N level configuration to examine the absorption and dispersion properties modulated into different ways along the lattice direction z. We find these trapped atoms with a Gaussian density distribution in each period may exhibit either symmetry Χp(z) = Χp∗ (-z) or antisymmetry Χp (z) = -Χp∗ (-z) of parity-time (PT ) in terms of the probe susceptibility. Such intriguing twofold modulations of real (Χ′p) and imaginary (Χ″p) susceptibilities with a π/2 phase shift are attained by spatially modulating intensities or frequencies of one driving field in a suitable way. The PT -symmetric or PT -antisymmetric atomic lattices correspond in fact to complex photonic crystals and may be extended to develop functional devices like photonic diodes and transistors, a task impossible for real photonic crystals. © 2016 Optical Society of America.

Godefroit P.,Royal Belgian Institute Of Natural Sciences | Godefroit P.,Jilin University | Demuynck H.,Vrije Universiteit Brussel | Dyke G.,University of Southampton | And 4 more authors.
Nature Communications | Year: 2013

Feathered theropods were diverse in the Early Cretaceous Jehol Group of western Liaoning Province, China. Recently, anatomically distinct feathered taxa have been discovered in the older Middle-Late Jurassic Tiaojishan Formation in the same region. Phylogenetic hypotheses including these specimens have challenged the pivotal position of Archaeopteryx in bird phylogeny. Here we report a basal troodontid from the Tiaojishan Formation that resembles Anchiornis, also from Jianchang County (regarded as sister-taxa). The feathers of Eosinopteryx are less extensive on the limbs and tail than Anchiornis and other deinonychosaurians. With reduced plumage and short uncurved pedal claws, Eosinopteryx would have been able to run unimpeded (with large foot remiges cursorial locomotion was likely problematic for Anchiornis). Eosinopteryx increases the known diversity of small-bodied dinosaurs in the Jurassic, shows that taxa with similar body plans could occupy different niches in the same ecosystem and suggests a more complex picture for the origin of flight. © 2013 Macmillan Publishers Limited. All rights reserved.

Ababei R.,CNRS Paul Pascal Research Center | Ababei R.,CNRS Laboratory of Condensed Matter Chemistry, Bordeaux | Pichon C.,CNRS Paul Pascal Research Center | Pichon C.,National Polytechnic Institute of Toulouse | And 8 more authors.
Journal of the American Chemical Society | Year: 2013

The spin-crossover complex [Fe(LN5)(CN)2] ·H2O (1, LN5 = 2,13-dimethyl-3,6,9-12,18- pentaazabicyclo[12.3.1]octadeca-1(18),2,12,14,16-pentaene), reported previously by Nelson et al. in 1986, was reinvestigated, and its structure determined by single crystal X-ray diffraction for the first time. The reaction between [MnIII(saltmen)(H2O)]+ and this photomagnetic linker yielded the trinuclear molecular complex [{Mn(saltmen)} 2FeHS(LN5)(CN)2](ClO 4)2·0.5CH3OH (2) and the one-dimensional compound [{Mn(saltmen)}2FeLS(LN5)(CN) 2](ClO4)2·0.5C4H 10O·0.5H2O (3) depending on the addition order of the reagents (HS: High-Spin; LS: Low-Spin). Compound 3 exhibits a wave-shaped chain structure built from the assembly of the trinuclear [Mn III-NC-FeII] motif found in 2. Static magnetic measurements revealed the existence of antiferromagnetic Mn III···FeII (FeII HS, S = 2) interactions in the trinuclear entity of 2 via the cyanido bridge leading to an ST = 2 ground state. In the case of 3, concomitant ferromagnetic and antiferromagnetic exchange interactions are found along the chain due to the presence of two crystallographically independent {Mn2(saltmen) 2} units, which behave differently as shown by the magnetic susceptibility analysis, while the FeII (LS, S = 0) cyanido-bridging moiety is isolating these dinuclear MnIII units. ac susceptibility experiments indicated slow relaxation of the magnetization arising from the ferromagnetically coupled [Mn2] units (τ0 = 1.1 × 10-7 s and Δeff/kB = 13.9 K). Optical reflectivity and photomagnetic properties of 1 and 3 have been investigated in detail. These studies reveal that the photomagnetic properties of 1 are kept after its coordination to the acceptor MnIII/saltmen complexes, allowing in 3 to switch "on" and "off" the magnetic interaction between the photoinduced FeII HS unit (S = 2) and the Mn(III) ions. To the best of our knowledge, the compound 3 represents the first example of a coordination network of single-molecule magnets linked by spin-crossover units inducing thermally and photoreversible magnetic and optical properties. © 2013 American Chemical Society.

Zhou K.,Northeast Normal University | Qin C.,Northeast Normal University | Li H.-B.,Northeast Normal University | Yan L.-K.,Northeast Normal University | And 5 more authors.
Chemical Communications | Year: 2012

Bridging between silver clusters and polyoxoanion clusters, the first 1D assembly, [Ag 34(S tBu) 26(W 6O 21)(CF 3COO)](CF 3COO)·Et 3N·20CH 3OH (1), based on POM-templated silver-thiolate nanoclusters featuring a [Ag 34(S tBu) 26(CF 3COO)] 7+ shell and a [W 6O 21] 6- core is reported. This novel core-shell nanocluster possesses nanoscopic morphology, displays intense deep-blue emission in solution under ambient conditions and also shows special electrochemical properties. © 2012 The Royal Society of Chemistry.

Zhang L.,Northeast Normal University | Wang T.,Changchun University of Science and Technology | Li L.,Northeast Normal University | Wang C.,Northeast Normal University | And 2 more authors.
Chemical Communications | Year: 2012

A facile, mild, environmentally friendly and reproducible strategy was used to fabricate the multifunctional fluorescent-magnetic polyethyleneimine functionalized Fe3O4-mesoporous silica yolk-shell nanocapsules for simultaneous fluorescent tracking and magnetically guided small interfering RNA delivery. © 2012 The Royal Society of Chemistry.

Li S.,Northeast Normal University | Liu S.,Northeast Normal University | Liu S.,Jilin University | Liu Y.,Northeast Normal University | And 4 more authors.
Journal of the American Chemical Society | Year: 2012

Four novel polytantalotungstates K5Na4[P 2W15O59(TaO2)3] •17H2O (1), K8Na8H4[P 8W60Ta12(H2O)4(OH) 8O236]•42H2O (2), Cs3K 3.5H0.5[SiW9(TaO2)3O 37]•9H2O (3), and Cs10.5K 4H5.5[Ta4O6(SiW9Ta 3O40)4]•30H2O (4) were synthesized. Compounds 1 and 3 are tris-(peroxotantalum)-substituted Dawson- and Keggin-type derivatives, whereas 2 and 4 are tetrameric oligomers containing respectively an unprecedented {Ta12} and {Ta16} cluster core. The photocatalytic activities of 2 and 4 for H2 evolution from water were evaluated. The significantly enhanced performance against the control K6[P2W18O62] can be attributed to the modulation of the electronic structures of these novel POMs by Ta incorporation. The highest activity observed so far with the use of 2 can be further rationalized by the presence of distorted heptacoordinate Ta atoms in the form of TaO7 pentagonal bipyramid. © 2012 American Chemical Society.

Zheng M.,University of Tennessee at Knoxville | He C.,Northeast Normal University | He Q.,University of Tennessee at Knoxville
Ecotoxicology | Year: 2015

Free chlorine is a potent oxidizing agent and has been used extensively as a disinfectant in processes including water treatment. The presence of free chlorine residual is essential for the prevention of microbial regrowth in water distribution systems. However, excessive levels of free chlorine can cause adverse health effects. It is a major challenge to maintain appropriate levels of free chlorine residual in premise plumbing. As the first effort to assessing the fate of chlorine in premise plumbing using actual premise plumbing pipe sections, three piping materials frequently used in premise plumbing, i.e. copper, galvanized iron, and polyvinyl chloride (PVC), were investigated for their performance in maintaining free chlorine residual. Free chlorine decay was shown to follow first-order kinetics for all three pipe materials tested. The most rapid chlorine decay was observed in copper pipes, suggesting the need for higher chlorine dosage to maintain appropriate levels of free chlorine residual if copper piping is used. PVC pipes exhibited the least reactivity with free chlorine, indicative of the advantage of PVC as a premise plumbing material for maintaining free chlorine residual. The reactivity of copper piping with free chlorine was significantly hindered by the accumulation of pipe deposits. In contrast, the impact on chlorine decay by pipe deposits was not significant in galvanized iron and PVC pipes. Findings in this study are of great importance for the development of effective strategies for the control of free chlorine residual and prevention of microbiological contamination in premise plumbing. © 2015, Springer Science+Business Media New York.

Li X.,Northeast Normal University | Li X.,Jilin University | Yin M.,Northeast Normal University | Yin M.,Jilin University
International Journal of Production Research | Year: 2013

The permutation flow shop problem (PFSSP) is an NP-hard problem of wide engineering and theoretical background. In this paper, a cuckoo search (CS)-based memetic algorithm, called HCS, is proposed for the PFSSP. To make CS suitable for the PFSSP, a largest-ranked-value (LRV)-rule-based random key is used to convert the continuous position in CS into a discrete job permutation. The Nawaz-Enscore-Ham (NEH) heuristic is then combined with the random initialisation to initialise the population with a certain quality and diversity. After that, CS is employed to evolve nest vectors for exploration, and a fast local search is embedded to enhance the local exploitation ability. In addition, simulations and comparisons based on PFSSP benchmarks are carried out, which shows that our algorithm is both effective and efficient. © 2013 Taylor and Francis Group, LLC.

Liu H.,Jilin University | Liu L.,Jilin University | Zhang H.,Northeast Normal University
Applied Soft Computing Journal | Year: 2011

Besides preprocessing, post-analysis also plays an important role in knowledge discovery. It can effectively assist users to grasp the obtained knowledge. However, many of data mining algorithms merely take performance into consideration and put the post-analysis of results aside. They generate a modest number of rules for the purpose of improving accuracy. Unfortunately, most induced rules are redundant or insignificant. Their presence not only confuses end-users in post-analysis, but also degrades efficiency in future decision task. Thus, it is necessary to eliminate redundant or irrelevant rules as more as possible. In this paper, we present an efficient post-processing method to prune redundant rules by virtue of the property of Galois connection, which inherently constrains rules with respect to objects. Its advantage is that information will not be lost greatly during pruning step. The experimental evaluation shows that the proposed method is competent for discarding a large number of superfluous rules effectively and a high compression factor will be achieved. What's more, the computational cost of our method is surprisingly lower than the Apriori method. © 2010 Elsevier B.V. All rights reserved.

Zhang J.,Northeast Normal University | Fan M.,Northeast Normal University | Zhu H.,York University
Computers and Mathematics with Applications | Year: 2010

In this paper, we define the exponential dichotomy of linear dynamic equations on time scales, then we present perturbation theorems on the roughness of exponential dichotomy, and develop several explicit sufficient criteria for linear dynamic equations to have an exponential dichotomy. As applications of the criteria of exponential dichotomy, we derive some new sufficient conditions for the existence of periodic solutions of semi-linear dynamic equations and nonlinear dynamic equations on time scales. © 2010 Elsevier Ltd. All rights reserved.

Zhong R.-L.,Northeast Normal University | Xu H.-L.,Northeast Normal University | Li Z.-R.,Jilin University | Su Z.-M.,Northeast Normal University
Journal of Physical Chemistry Letters | Year: 2015

The excess electron is a kind of special anion with dispersivity, loosely bounding and with other fascinating features, which plays a pivotal role (promote to about 106 times in (H2O)3{e}) in the large first hyperpolarizabilities (?0) of dipole-bound electron clusters. This discovery opens a new perspective on the design of novel nonlinear optical (NLO) molecular materials for electro-optic device application. Significantly, doping alkali metal atoms in suitable complexants was proposed as an effective approach to obtain electride and alkalide molecules with excess electron and large NLO responses. The first hyperpolarizability is related to the characteristics of complexants and the excess electron binding states. Subsequently, a series of new strategies for enhancing NLO response and electronic stability of electride and alkalide molecules are exhibited by using various complexants. These strategies include not only the behaviors of pushed and pulled electron, size, shape, and number of coordination sites of complexants but also the number and spin state of excess electrons in these unusual NLO molecules. © 2015 American Chemical Society.

Ai X.,Jilin University | Niu L.,Jilin University | Li Y.,Northeast Normal University | Yang F.,Jilin University | Su X.,Jilin University
Talanta | Year: 2012

In this paper, a novel optical biosensor for amantadine (AD) determination has been constructed successfully based on the fluorescence resonance energy transfer (FRET) between water-soluble β-Cyclodextrin (β-CD)- functionalized CdTe quantum dots (QDs) and Rhodamine B (RB). RB could enter the cavity of β-CD by hydrophobic interaction, and the process of FRET between QDs and RB occurred. However, the process of FRET was switched off with the addition of AD, due to its larger hydrophobic association constant with β-CD than that of RB. The fluorescence intensity of CdTe QDs (donor) would increase gradually with the increasing concentration of AD, which shown a good linear relationship in the range of 1×10-5-1.6×10 -4 mol/L with a correlation coefficient R2=0.998. We also obtained a satisfactory result using this spectrophotometric method for the determination of AD in pharmaceutical formulation. Furthermore, β-CD-functionalized CdTe QDs with AD in the cavity were incubated with target HepG2 cells and could be observed in the cytoplasm of cells. The β-CD-functionalized CdTe QDs could act as a visible biomarker for AD in cancer cells fluorescence imaging, which presents a potential application in biomedical field. © 2012 Elsevier B.V.

Zhang L.,Northeast Normal University | Wang T.,Changchun University of Science and Technology | Yang L.,Jilin University | Liu C.,Northeast Normal University | And 4 more authors.
Chemistry - A European Journal | Year: 2012

Hollow mesoporous SiO2 (mSiO2) nanostructures with movable nanoparticles (NPs) as cores, so-called yolk-shell nanocapsules (NCs), have attracted great research interest. However, a highly efficient, simple and general way to produce yolk-mSiO2 shell NCs with tunable functional cores and shell compositions is still a great challenge. A facile, general and reproducible strategy has been developed for fabricating discrete, monodisperse and highly uniform yolk-shell NCs under mild conditions, composed of mSiO 2 shells and diverse functional NP cores with different compositions and shapes. These NPs can be Fe3O4 NPs, gold nanorods (GNRs), and rare-earth upconversion NRs, endowing the yolk-mSiO2 shell NCs with magnetic, plasmonic, and upconversion fluorescent properties. In addition, multifunctional yolk-shell NCs with tunable interior hollow spaces and mSiO2 shell thickness can be precisely controlled. More importantly, fluorescent-magnetic-biotargeting multifunctional polyethyleneimine (PEI)-modified fluorescent Fe3O4@mSiO2 yolk-shell nanobioprobes as an example for simultaneous targeted fluorescence imaging and magnetically guided drug delivery to liver cancer cells is also demonstrated. This synthetic approach can be easily extended to the fabrication of multifunctional yolk@mSiO2 shell nanostructures that encapsulate various functional movable NP cores, which construct a potential platform for the simultaneous targeted delivery of drug/gene/DNA/siRNA and bio-imaging. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhang Y.,Northeast Normal University | Liu Y.-M.,Jilin University | Tian X.-D.,Jilin University | Zheng T.-Y.,Northeast Normal University | Wu J.-H.,Northeast Normal University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

We study a five-level quasi-Λ system of cold atoms for achieving high-order photonic band gaps (PBGs) probed by an ultraviolet field in two cases where either an infrared or a visible control field works in the standing-wave configuration to induce one atomic grating. Transfer-matrix calculations for appropriate rubidium levels demonstrate that three fifth-order band gaps or two second-order band gaps can be generated near the probe resonance when the standing-wave control field is modulated to satisfy relevant Bragg conditions in the regime of electromagnetically induced transparency. These high-order PBGs, as characterized by homogeneous high reflectivities, can be dynamically tuned in positions and widths on demand and may be extended to develop efficient devices (like diodes and reflectors) for manipulating weak high-frequency light with strong low-frequency light. © 2015 American Physical Society.

Qin J.Y.,Northeast Normal University | Qin J.Y.,Howard Hughes Medical Institute | Zhang L.,Howard Hughes Medical Institute | Clift K.L.,Howard Hughes Medical Institute | And 4 more authors.
PLoS ONE | Year: 2010

Constitutive promoters are used routinely to drive ectopic gene expression. Here, we carried out a systematic comparison of eight commonly used constitutive promoters (SV40, CMV, UBC, EF1A, PGK and CAGG for mammalian systems, and COPIA and ACT5C for Drosophila systems). We also included in the comparison the TRE promoter, which can be activated by the rtTA transcriptional activator in a doxycycline-inducible manner. To make our findings representative, we conducted the comparison in a variety of cell types derived fromseveral species.We found that these promoters vary considerably fromone another in their strength.Most promoters have fairly consistent strengths across different cell types, but the CMV promoter can vary considerably fromcell type to cell type. Atmaximal induction, the TRE promoter is comparable to a strong constitutive promoter. These results should facilitate more rational choices of promoters in ectopic gene expression studies. © 2010 Qin et al.

Chen H.,Northeast Normal University | Wang F.,Northeast Normal University | Tong S.,Jilin University | Guo S.,Northeast Normal University | Pan X.,Northeast Normal University
Applied Surface Science | Year: 2012

A series of porous carbon samples as electric double layer capacitor electrode materials were prepared by a pyrolysis process using phenol formaldehyde resin (PF) as precursors and KOH/ZnCl 2 as activation agents. Porous carbon samples were characterized by thermogravimetric analysis, X ray diffraction, nitrogen adsorption/desorption isotherms and transmission electron microscopy. The results showed that the KOH/ZnCl 2/PF mass mixing ratio and activation temperature had a remarkable effect on the porosity, the specific surface area and the pore size of the carbons. The prepared carbon material PC-6 exhibits a high specific capacitance of 141.56 F/g and a average specic energy of 74.13 Wh/kg at a current density of 120 mA/g in the electrolyte of 1 M Et 3MeNBF 4/PC, and the average specic energy still remained 49.48 Wh/kg even at a high current density of 2000 mA/g. The excellent electrochemical behavior of PC-6 can be attributed to the highly development pore structure. © 2012 Elsevier B.V. All rights reserved.

Hamid A.S.,Jilin University | Tesfamariam S.G.,Northeast Normal University | Zhang Y.,Jilin University | Zhang Z.G.,Jilin University
Oncology Letters | Year: 2013

Hepatocellular carcinoma (HCC) is the most well-known primary liver malignancy worldwide. Its incidence is rising at alarming rates and has become a public concern globally. It is more frequent in developing countries than in industrialized countries with respect to geographical variation, ethnic disparities and socioeconomic status. Dietary exposure to aflatoxins is among the major HCC risk factors. Aflatoxin B1, which is a genotoxic hepatocarcinogen, which presumptively causes cancer by inducing DNA adducts leading to genetic changes in target liver cells. AFB1 is metabolized by cytochrome-P450 enzymes to the reactive intermediate AFB1-8, 9 epoxide (AFBO) which binds to liver cell DNA, resulting in DNA adducts. DNA adducts interact with the guanine bases of liver cell DNA and cause a mutational effect in the P53 tumor suppressor gene at the codon 249 hotspot in exon 7, which may lead to HCC. Approximately 4.5 billion of the world's population is exposed to aflatoxin-contaminated food, particularly in low-income countries. Prevention involves treating crops that are susceptible to fungal contamination, appropriate handling of foodstuffs and the use of chemopreventive intervention. Moreover, an integrated network collaboration of different sectors, including public health, agricultural departments and mass media, is required to ensure effective food regulation systems so as to minimize the contamination of food by aflatoxins.

Tang Q.,Northeast Normal University | Liu S.,Northeast Normal University | Liu Y.,Northeast Normal University | Miao J.,Northeast Normal University | And 5 more authors.
Inorganic Chemistry | Year: 2013

A series of novel lanthanide metal-organic frameworks were synthesized using a ligand featuring three carboxylate groups stationed on a triazinyl central motif. The readily accessible multiple Lewis basic triazinyl N atoms allow for complexation of incoming metal ions. Such interactions have been established quantitatively. © 2013 American Chemical Society.

Qin J.-S.,Jilin University | Qin J.-S.,Northeast Normal University | Zhang S.-R.,Northeast Normal University | Du D.-Y.,Northeast Normal University | And 5 more authors.
Chemistry - A European Journal | Year: 2014

Herein, a novel anionic framework with primitive centered cubic (pcu) topology, [(CH3)2NH2]4[(Zn 4dttz6)Zn3] 15DMF 4.5H2O, (IFMC-2; H3dttz=4,5-di(1H-tetrazol-5-yl)-2H-1,2,3-triazole) was solvothermally isolated. A new example of a tetranuclear zinc cluster {Zn4dttz 6} served as a secondary building unit in IFMC-2. Furthermore, the metal cluster was connected by ZnII ions to give rise to a 3D open microporous structure. The lanthanide(III)-loaded metal-organic framework (MOF) materials Ln3+@IFMC-2, were successfully prepared by using ion-exchange experiments owing to the anionic framework of IFMC-2. Moreover, the emission spectra of the as-prepared Ln3+@IFMC-2 were investigated, and the results suggested that IFMC-2 could be utilized as a potential luminescent probe toward different Ln3+ ions. Additionally, the absorption ability of IFMC-2 toward ionic dyes was also performed. Cationic dyes can be absorbed, but not neutral and anionic dyes, thus indicating that IFMC-2 exhibits selective absorption toward cationic dyes. Furthermore, the cationic dyes can be gradually released in the presence of NaCl. A tetranuclear metal cluster with primitive centered cubic (pcu) topology, IFMC-2, was synthesized as a new anionic metal-organic framework (MOF). The Ln3+-loaded MOF materials were successfully prepared by ion exchange, and the emission spectra indicated that IFMC-2 is suitable for the sensitization of Tb3+ and Dy3+ ions rather than as a Eu3+ and Sm3+ emitter (see picture). Additionally, IFMC-2 exhibits selective absorption toward cationic dyes, which can be gradually released in the presence of NaCl. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Jin R.,Northeast Normal University | Yang Y.,Northeast Normal University | Zou Y.,Jilin University | Liu X.,Northeast Normal University | Xing Y.,Northeast Normal University
Chemistry - A European Journal | Year: 2014

Hollow mesoporous structures have recently aroused intense research interest owing to their unique structural features. Herein, an effective and precisely controlled synthesis of hollow rare-earth silicate spheres with mesoporous shells is reported for the first time, produced by a simple hydrothermal method, using silica spheres as the silica precursors. The as-prepared hollow rare-earth silicate spheres have large specific surface area, high pore volume, and controllable structure parameters. The results demonstrate that the selection of the chelating reagent plays critical roles in forming the hollow mesoporous structures. In addition, a simple and low-energy-consuming approach to synthesize highly stable and dispersive gold nanoparticle-yttrium silicate (AuNPs/YSiO) hollow nanocomposites has also been developed. The reduction of 4-nitrophenol with AuNPs/YSiO hollow nanocomposites as the catalyst has clearly demonstrated that the hollow rare-earth silicate spheres are good carriers for Au nanoparticles. This strategy can be extended as a general approach to prepare multifunctional yolk-shell structures with diverse compositions and morphologies simply by replacing silica spheres with silica-coated nanocomposites. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Huang J.,Jilin University | Wang X.,Northeast Normal University | Li S.,Jilin University | Wang Y.,Jilin University
Applied Surface Science | Year: 2010

As a continuation of our work to develop catalysts with high activity for catalytic air wet oxidation process under mild conditions, degradation of wastewater containing 0.3 g/L Safranin-T (ST) by air oxidation over ZnO/MoO 3 nanotube catalyst was studied. It was found the decolorization efficiency and the chemical oxygen demand (COD) removal of ST reached above 98% and 95%, respectively, within 18 min at room temperature and atmospheric pressure. And the organic pollutants were totally mineralized to simple inorganic species such as HCO3 -, Cl- and NO3 -, while the total organic carbon (TOC) decreased 99.3%. The structure and morphology of the catalyst after ten cycling runs showed that the catalyst was stable under such operating condition and the leaching test showed negligible leaching effect. This ZnO/MoO3 nanotube is proved to be an active and stable heterogeneous catalyst in CWAO of ST under extremely mild conditions. © 2010 Elsevier B.V. All rights reserved.

Liu F.,Jilin University | Li W.,Northeast Normal University | Sun Q.,Zhejiang University | Zhu L.,Jilin University | And 3 more authors.
ChemSusChem | Year: 2011

Super combo: Superhydrophobic and porous solid bases are synthesized by co-polymerization of divinylbenzene (DVB) and 1-vinylimidazolate (VI). The materials show higher activities towards the transesterification of tripalmitin with methanol than conventional bases and VI mono-/polymer. Their performance is attributed to the synergy of superhydrophobicity combined with active VI sites. These catalysts also remain very active upon recycling. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gao P.,Northeast Normal University | Gao P.,Jilin University
ESAIM - Control, Optimisation and Calculus of Variations | Year: 2016

In this paper, we establish the Lebeau-Robbiano inequality for the one-dimensional fourth order elliptic operator by using a point-wise estimate. Based on this inequality, we obtain the null controllability of one-dimensional stochastic fractional order Cahn-Hilliard equation. © EDP Sciences, SMAI 2016.

Jiang Y.,Northeast Normal University | Liu S.,Northeast Normal University | Li S.,Northeast Normal University | Miao J.,Northeast Normal University | And 2 more authors.
Chemical Communications | Year: 2011

Non-mesogenic unit bearing Keggin-type polyoxoanions with tetra-n-octylammonium counterions exhibit an ionic liquid crystalline structure via ionic self-assembly in a certain temperature range. © 2011 The Royal Society of Chemistry.

Zhang Y.,Northeast Normal University | Wang G.,Northeast Normal University | He Y.,Jilin University
Dyes and Pigments | Year: 2014

The fluorescent photo-switching systems were prepared based on fluorescent pyrene and photochromic naphthopyran in the forms of organic dyad and copolymer. Naphthopyran in two systems displayed excellent photochromic performance, especially in tetrahydrofuran solution. The fluorescent emission was modulated between "on" and "off" via the photoisomerization of naphthopyran in high-degree, especially in polymer (>90%) due to the photoinduced energy transfer from pyrene excimers to the open-form naphthopyran. Both the fluorescence photoswitching and the photochromism of polymer in solution displayed excellent fatigue resistance. The fluorescent image shows the patterned irradiation of the polymer-doped polymethylmethacrylate film can be recorded by fluorescent pattern on the sample. The non-destructive readout ability of polymer-doped polymethylmethacrylate film was achieved. © 2013 Elsevier Ltd. All rights reserved.

Gao H.,CAS Changchun Institute of Applied Chemistry | Gao H.,Jilin University | Li Y.,Northeast Normal University | Zhou Y.-G.,CAS Changchun Institute of Applied Chemistry | And 2 more authors.
Advanced Synthesis and Catalysis | Year: 2011

We present a highly active, inexpensive, universally applicable, and markedly stable [1,3-bis(diphenylphosphino)propane]nickel(II) chloride [Ni(dppp)Cl2] catalyst that is capable of effecting the Suzuki-Miyaura cross-coupling of the inherently less reactive but readily available aryl tosylates and mesylates with only 1amol% loading and in the absence of extra supporting ligand. Under the optimized reaction conditions, cross-coupling of a wide range of activated, non-activated, and deactivated, as well as sterically hindered and heteroaromatic substrates (36 examples) could proceed efficiently to afford the coupled products in 53-99% yields. Consequently, the results presented in this work provide a significant advance in Suzuki-Miyaura cross-coupling in terms of generality, practicality, and cost which are key concerns in recent research regarding transition metal-catalyzed cross-couplings. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gao P.,Northeast Normal University | Gao P.,Jilin University
Computers and Mathematics with Applications | Year: 2015

This paper is addressed to study the null controllability with constraints on the state for the reaction-diffusion system. We transform the problem into an equivalent null controllability problem with constraint on the control. Using a Carleman inequality adapted to the constraint, we prove the null controllability with constraints on the state for the reaction-diffusion system holds. © 2015 Elsevier Ltd.

Chen W.-C.,Northeast Normal University | Li H.-L.,Jilin University | Wang X.-L.,Northeast Normal University | Shao K.-Z.,Northeast Normal University | And 2 more authors.
Chemistry - A European Journal | Year: 2013

A versatile one-pot strategy was employed to synthesize three cerium(III)-stabilized polyoxotungstates nanoclusters by combining cerium linkers and SeO3 2-/TeO3 2- heteroanion templates: K32Na16[{(XO3)W 10O34}8{Ce8(H2O) 20}(WO2)4- (W4O12)] ×n H2O [X=Se, n=81 (1); X=Te, n=114 (2)] and K 12Na22[{(SeO3)W10O 34}8{Ce8(H2O)20}(WO 2)4- {(W4O6)Ce4(H 2O)14(SeO3)4(NO3) 2}]× 79 H2O (3), which are the first lanthanide-containing polyoxotungstates with selenium or tellurium heteroatoms. The three clusters were characterized by single-crystal X-ray structure analysis, IR spectroscopy, thermogravimetric/differential thermal analysis, UV/Vis spectroscopy, ESI-MS, and X-ray photoelectron spectroscopy. Their electrochemical, photoluminescence, and magnetic properties were investigated. Their behavior in solution was studied by transmission electron microscopy, which showed that their single polyoxoanions assemble into intact, uniform-sized, purely inorganic hollow spheres in dilute water/acetone solution. © 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tian A.,Bohai University | Ying J.,Bohai University | Wang X.,Bohai University | Peng J.,Northeast Normal University
Inorganic Chemistry Communications | Year: 2011

A new Keggin POM-based compound, [Cd2(H2O) 2(btb)4(SiMo12O40)] (1) (btb = 1,4-bis(1,2,4-triazol-1-y1)butane), was synthesized under hydrothermal conditions. Compound 1 exhibits 2D wave-like metal-organic layers, which are further linked by Keggin [SiMo12O40]4- anions to construct a 3D framework containing two kinds of quadrate channels. The void left by channels induces an interesting two-fold interpenetrating structure. © 2010 Elsevier B.V. All rights reserved.

Yang G.,Jilin University | Yang G.,Northeast Normal University | Wang Y.,Jilin University | Ma Y.,Jilin University
Journal of Physical Chemistry Letters | Year: 2014

The Li-air battery with the specific energy exceeding that of a Li ion battery has been aimed as the next-generation battery. The improvement of the performance of the Li-air battery needs a full resolution of the actual discharge products. Li2O2 has been long recognized as the main discharge product, with which, however, there are obvious failures on the understanding of various experimental observations (e.g., magnetism, oxygen K-edge spectrum, etc.) on discharge products. There is a possibility of the existence of other Li-O compounds unknown thus far. Here, a hitherto unknown Li3O4 compound as a discharge product of the Li-air battery was predicted through first-principles swarm structure searching calculations. The new compound has a unique structure featuring the mixture of superoxide O2 - and peroxide O2 2-, the first such example in the Li-O system. The existence of superoxide O 2 - creates magnetism and hole-doped metallicity. Findings of Li3O4 gave rise to direct explanations of the unresolved experimental magnetism, triple peaks of oxygen K-edge spectra, and the Raman peak at 1125 cm-1 of the discharge products. Our work enables an opportunity for the performance of capacity, charge overpotential, and round-trip efficiency of the Li-air battery. © 2014 American Chemical Society.

Pu F.,CAS Changchun Institute of Applied Chemistry | Wang E.,Northeast Normal University | Jiang H.,Jilin University | Ren J.,CAS Changchun Institute of Applied Chemistry
Molecular BioSystems | Year: 2013

Angiogenesis is the process of new blood vessel formation from pre-existing ones. Angiogenic factors contribute to neovascularization that takes place in angiogenesis-dependent diseases, including cancer. Inhibiting the activity of the angiogenic factors to block the angiogenesis pathways is the current strategy of cancer therapy. Basic fibroblast growth factor (bFGF) is regarded as one of the most important angiogenic factors. Herein, we selected polyoxometalates (POMs) with different structures to study the interactions between bFGF and POMs. The results show that POMs could bind to the protein with high affinity, causing detectable changes in conformation and biophysical properties of protein. In addition, POMs could effectively inhibit the cell proliferation induced by bFGF. Significantly, we found that the structure, size and composition of POMs play a key role in the interactions between bFGF and POMs. This study will be meaningful for future screening and design of polyoxometalate-based anticancer drugs. © 2013 The Royal Society of Chemistry.

Wang X.,Northeast Normal University | Wang X.,Bohai University | Peng J.,Northeast Normal University | Alimaje K.,Northeast Normal University | Shi Z.-Y.,Northeast Normal University
CrystEngComm | Year: 2012

By altering the functional groups of tetrazolate ligands in the same Ag-POM reaction system, two novel inorganic-organic hybrids: [Ag7(L 1)4(H2O)(PMo12O40)] (1) and [Ag5(L2)2(PMo12O 40)]·H2O (2) (HL1 = 5-(4-imidazol-1-yl- phenyl)-2H-tetrazole, HL2 = 5-(4-triazol-1-ylmethyl-phenyl)-2H- tetrazole), have been synthesized under hydrothermal conditions, which are characterized by single crystal X-ray diffraction, IR spectra and elemental analyses. Compounds 1 and 2 both display POM-based 3D frameworks modified by different Ag-tetrazolate motifs. In compound 1, a beautiful POM-inserted 2D network is formed by {Ag6(L1)4}n chains and POM polyoxoanions, which are linked to each other through covalent bonds into a (6,6,10)-connected 3D framework. The 3D framework of compound 2 is constructed from chains of circle-connecting-circle and dimeric polyoxoanions. The different structural features of the two compounds suggest that the functional groups of tetrazolate ligands should play a key role in the process of assembly. The luminescent properties for compounds 1 and 2 are investigated. This journal is © The Royal Society of Chemistry.

Chang Y.-F.,CAS Changchun Institute of Applied Chemistry | Chang Y.-F.,Northeast Normal University | Lu Z.-Y.,Jilin University | An L.-J.,CAS Changchun Institute of Applied Chemistry | Zhang J.-P.,Northeast Normal University
Journal of Physical Chemistry C | Year: 2012

The reorganization energy and the charge transfer integral between the initial and final states are two key parameters of charge transport. In this study, we find that the internal reorganization energies of molecules can be reduced effectively by cyanation on the tetracene molecule, which is helpful to improve the carrier mobilities of investigated molecules. On the basis of the polymorph predictor, the appreciated crystal structures of 5-cyanotetracene (1CT), 5,11-dicyanotetracene (2CT), and 5,6,11,12-tetracyanotetracene (4CT) with π-π stacking favorable to enhance the charge transfer integral were obtained. Benefiting from a low internal reorganization energy and dense packing structure, high hole motilities (6.0 and 6.2 cm 2 V -1 s -1 for 1CT-9 and 4CT-2, respectively) were achieved. Both 1CT-9 and 4CT-2 are promising candidates for high carrier mobility organic optoelectronic functional materials. The process that constructs crystal structures from single molecules provides a rational way for the search of high-performance organic photovoltaic materials. © 2011 American Chemical Society.

Zhao Y.,Northeast Normal University | Zhao Y.,Changchun University | Jiang D.,Northeast Normal University | O'Regan D.,National University of Ireland
Physica A: Statistical Mechanics and its Applications | Year: 2013

In this paper, we discuss the dynamics of a stochastic SIS epidemic model with vaccination. When the noise is large, the infective decays exponentially to zero regardless of the magnitude of R0. When the noise is small, sufficient conditions for extinction exponentially and persistence in the mean are established. The results are illustrated by computer simulations. © 2013 Elsevier B.V. All rights reserved.

Cai D.,Wuhan Institute of Technology | Cai D.,Jilin University | Yin M.,Northeast Normal University
Knowledge-Based Systems | Year: 2012

Landmarks have been successfully employed in sequential planning, especially in the design of heuristic functions. However, little attention has been paid on exploiting landmarks in parallel planning. Here we propose a way to use the information of landmarks in SAT based planning, which is a successful framework for generating parallel plans. Specifically, we propose a way to encode landmarks and their orderings of a planning task into clauses, which are then integrated into the encoding of the task. We call those clauses landmark clauses. Landmark clauses are additional constraints that have the potential to help a SAT solver prune its search space considerably. However, for modern SAT solvers that employ more advanced reasoning or clause learning techniques, the effect of landmark clauses could be not intuitive. Therefore, our major work is giving examples and further identifying conditions under which landmark clauses are not logically redundant. We identify types of landmark clauses that cannot be derived by unit propagation, binary resolution or hyper resolution. Importantly, we prove that not all landmark clauses are redundant in terms of the UP-redundancy that was proposed by Sideris and Dimopoulos in 2010. We also conducted experiments on benchmarks from International Planning Competitions. The results show that MiniSat, a state-of-the-art SAT solver with the clause learning ability, with landmark clauses can be more efficient than it without landmark clauses on some hard planning problems. Therefore, we argue that landmarks and their orderings have promising effects in speeding up SAT based planning methods. © 2012 Elsevier B.V. All rights reserved.

Chang X.,Northeast Normal University | Chang X.,Jilin University
Journal of Mathematical Physics | Year: 2013

This paper is devoted to a time-independent fractional Schrödinger equation of the form (-δ)su+V(x)u=f(x,u)inRN, where N ≥ 2, s ∈ (0, 1), (-δ)s stands for the fractional Laplacian. We apply the variational methods to obtain the existence of ground state solutions when f(x, u) is asymptotically linear with respect to u at infinity. © 2013 AIP Publishing LLC.

Chen L.,Northeast Normal University | Tan K.,Changchun University | Lan Y.-Q.,Northeast Normal University | Li S.-L.,Northeast Normal University | And 2 more authors.
Chemical Communications | Year: 2012

Two isostructural 2D → 2D parallel → 3D inclined interpenetrating polycatenane-like metal-organic frameworks were successfully constructed based on length-adjusted tricarboxylate ligands. With the merit of being microporous, IFMC-10 can serve as host for encapsulating lanthanide cations and I 2 to exhibit luminescent sensing and rapid adsorption of iodine. © 2012 The Royal Society of Chemistry.

Sun L.,Jilin University | Xing H.,Northeast Normal University | Liang Z.,Jilin University | Yu J.,Jilin University | Xu R.,Jilin University
Chemical Communications | Year: 2013

A zeolitic metal-organic framework with a SOD topology, (Et 2NH2)[In(BCBAIP)]·4DEF·4EtOH (H 4BCBAIP: 5-(bis(4-carboxybenzyl)amino)isophthalic acid) (1), has been constructed by a 4 + 4 synthetic strategy from tetrahedral organic building units and In3+ ions. Compound 1 could adsorb organic dyes and be used as a light-harvesting antenna. © 2013 The Royal Society of Chemistry.

Wang J.,Northeast Normal University | Han D.,CAS Changchun Institute of Applied Chemistry | Wang X.,Northeast Normal University | Qi B.,Northeast Normal University | Zhao M.,Jilin University
Biosensors and Bioelectronics | Year: 2012

Polyoxometalates (H 3PW 12O 40, H 4SiW 12O 40 and H 3PMo 12O 40) have been proven to possess intrinsic peroxidase-like activity for the first time, which can catalyze oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) by H 2O 2 to form a blue color in aqueous solution. Among them, H 3PW 12O 40 (PW 12) exhibits higher catalytic activity to TMB than natural enzyme HRP and other two POMs. In addition, H 3PW 12O 40/graphene exhibited higher activity than H 3PW 12O 40 in this catalytic oxidation reaction due to the effect of graphene in promoting the electron transfer between the substrate and catalyst. POMs/H 2O 2/TMB system provides a simple, accurate approach to colorimetric detection for H 2O 2 or glucose. The colorimetric method based on POMs showed good response toward H 2O 2 and glucose detection with a linear range from 1.34×10 -7 to 6.7×10 -5mol/L and 1×10 -7 to 1×10 -4mol/L, respectively. The results showed that it is a simple, cheap, more convenient, highly selective, sensitive, and easy handling colorimetric assay. © 2012 Elsevier B.V.

Deng M.,Cornell University | Deng M.,Northeast Normal University | Wu J.,Cornell University | Reinhart-King C.A.,Cornell University | Chu C.-C.,Cornell University
Acta Biomaterialia | Year: 2011

The synthesis of a new family of biodegradable α-amino acid poly(ester amide)s (AA-PEAs) with pendant benzyl ether groups and hydroxyl functional groups is reported. The synthetic strategy employs the ring opening reaction of O-benzyl-l-serine-N-carboxyanhydride with di-p-toluenesulfonic acid salts of bis-l-valine butane-1,4-diester, followed by solution polycondesation reactions with di-p-nitrophenyl sebacate in N,N-dimethylacetamide. Catalytic hydrogenation of the resulting benzyl ether protected AA-PEAs (PEA-Ser-Bzs) was performed to restore the hydroxyl functional groups in the functionalized AA-PEAs (PEA-Ser-OH). All resulting polymers were characterized by standard physico-chemical methods. The pendant hydroxyl groups in PEA-Ser-OH were used to fabricate AA-PEA-based gels via acrylation and photo-gelation. The cell-polymer interactions of PEA-Ser-Bz and PEA-Ser-OH were evaluated in terms of cell attachment and proliferation assay using bovine aortic endothelial cells (BAECs) as well as fibroblasts. The cell culture data indicated that the hydrophobic/hydrophilic characteristics (from contact angle data) of these AA-PEAs could significantly affect the interaction between BAECs and AA-PEA. This finding may provide additional possible applications for this new family of functionalized AA-PEA polymers. © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Liu Y.-M.,Jilin University | Yan D.,Changchun University | Tian X.-D.,Jilin University | Cui C.-L.,Jilin University | And 2 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

We present an improved superatom model for examining nonlinear optical responses of cold Rydberg atoms in the regime of electromagnetically induced transparency (EIT). By going beyond the weak-probe approximation, we find that several higher-order collective states should be included to correctly describe the coherent Rydberg excitation of superatoms. Otherwise, numerical results based on the simple ladder system of superatoms will contribute wrong predictions on light intensity and photon correlation of the transmitted probe field. In particular, a great photon-bunching effect will be improperly expected somewhere out of the EIT window in one dilute atomic sample. The essence of this improved superatom model lies in that it can provide reliable predictions on the nonlinear Rydberg-EIT phenomena even in dense atomic samples and may be extended to realize lossless conditional light interactions in appropriate multilevel systems exhibiting dipole blockade. © 2014 American Physical Society.

Shen H.Z.,Dalian University of Technology | Qin M.,Dalian University of Technology | Xiu X.-M.,Dalian University of Technology | Xiu X.-M.,Bohai University | Yi X.X.,Northeast Normal University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

The driven two-level system is a useful model to describe many quantum objects, particularly in quantum information processing. However, the exact master equation for such a system has barely been explored. Making use of the Feynman-Vernon influence functional theory, we derive an exact non-Markovian master equation for the driven two-level system and show the lost feature in the perturbative treatment for this system. The perturbative treatment leads to the time-convolutionless (TCL) and Nakajima-Zwanzig (NZ) master equations. So to this end we derive the TCL and NZ master equations for the system and compare the dynamics given by the three master equations. We find the validity condition for the TCL and NZ master equations. Based on the exact non-Markovian master equation, we analyze the regime of validity for the secular approximation in the time-convolutionless master equation and discuss the leading corrections of the nonsecular terms to the quantum dynamics. Significant effects are found in the dynamics of the driven system. © 2014 American Physical Society.

Qin J.-S.,Northeast Normal University | Qin J.-S.,Jilin University | Du D.-Y.,Northeast Normal University | Li W.-L.,Northeast Normal University | And 8 more authors.
Chemical Science | Year: 2012

A novel zeolite-like metal-organic framework (ZMOF) with sodalite topology, [Zn(HL)]·DMA (IFMC-1, L = 4,5-di(1H-tetrazol-5-yl)-2H-1,2,3-triazole and IFMC = Institute of Functional Material Chemistry), was solvothermally synthesized based on an N-rich aromatic ligand without a NH 2 group. It exhibits high CO 2 uptake and selective CO 2/N 2 adsorption capacity. For the first time, we investigated the influence of a large number of uncoordinated nitrogen atoms from aromatic rings for CO 2 adsorption in ZMOFs. This result reveals that the high percentage of open N-donor sites leads to the high uptake capacity for CO 2, even in the absence of any NH 2 groups and open metal sites. In addition, it also exhibits efficient drug delivery capacity. © 2012 The Royal Society of Chemistry.

Su T.,Jilin University | Xing H.,Northeast Normal University | Xu J.,Jilin University | Yu J.,Jilin University | Xu R.,Jilin University
Inorganic Chemistry | Year: 2011

Three new open-framework metal borophosphates, [Na6Co 3B2P5O21Cl] . H2O (JIS-4),K5Mn2B2P5O 19(OH)2 (JIS-5), (NH4)8[Co 2B4P8O3o(OH)4](JIS-6), have been prepared under ionothermal conditions using ionic liquid 1-ethyl-3-methylimidazolium ([Emim]Br) as the solvent. They are the first examples of metalloborophosphate prepared by the ionothermal method. Their structures are determined by single-crystal X-ray diffraction. The 3-D open framework of JIS-4 is made of CoO5Cl octahedra, CoO5 square pyramids, and PO4 and BO4 tetrahedra forming 12-ring channels along the [010] direction. It is noted that JIS-4 is the first 3-D open-framework structure in the family of borophosphate with the B/P ratio of 2/5, which features a borophosphate cluster anionic partial structure. Such cluster anionic partial structures connect with MnO6 octahedra and MnO5 trigonal bipyramids resulting in the formation of the 2-D layer structure of JIS-5 with the same B/P ratio as JIS-4. The 2-D layer structure of JIS-6 belongs to the largest family of borophosphate with a B/P ratio of 1/2 which features a unique 1-D chain anionic partial structure. Crystal data for JIS-4, orthorhombic, Prima, a = 14.0638(8) Å, b = 9.8813(7) Å, c = 14.0008(10) Å, V = 1945.7(2) Å3,and Z =2; for JIS-5, monoclinic, P21/r, a = 14.4939(3) Å, b = 9.2539(3) Å, c = 14.8031 (4) Å, β = 101.4600(10)°, V = 1945.88(9) Å3, and Z =4.For JIS-6, triclinic, P1, a = 9.6928(3) Å, b = 9.8747(3) Å, c = 10.0125(2) Å, α = 62.057(2)°, β = 82.456(2°, γ = 76.095(2)°, V = 821.60(4) Å3,and Z =1.© 2011 American Chemical Society.

Li X.,Northeast Normal University | Yin M.,Northeast Normal University | Yin M.,Jilin University
Advances in Engineering Software | Year: 2013

The permutation flow shop problem (PFSSP) is an NP-hard problem of wide engineering and theoretical background. In this paper, a differential evolution (DE) based memetic algorithm, named ODDE, is proposed for PFSSP. First, to make DE suitable for PFSSP, a new LRV rule based on random key is introduced to convert the continuous position in DE to the discrete job permutation. Second, the NEH heuristic was combined the random initialization to the population with certain quality and diversity. Third, to improve the global optimization property of DE, a DE approach based on measure of population's diversity is proposed to tuning the crossover rate. Fourth, to improve the convergence rate of DE, the opposition-based DE employs opposition-based learning for the initialization and for generation jumping to enhance the global optimal solution. Fifth, the fast local search is used for enhancing the individuals with a certain probability. Sixth, the pairwise based local search is used to enhance the global optimal solution and help the algorithm to escape from local minimum. Additionally, simulations and comparisons based on PFSSP benchmarks are carried out, which show that our algorithm is both effective and efficient. We have also evaluated our algorithm with the well known DMU problems. For the problems with the objective of minimizing makespan, the algorithm ODDE obtains 24 new upper bounds of the 40 instances, and for the problems with the objective of maximum lateness, ODDE obtains 137 new upper bounds of the 160 instances. These new upper bounds can be used for future algorithms to compare their results with ours. © 2012 Elsevier Ltd. All rights reserved.

Liu M.,Harbin Institute of Technology | Wang K.,Harbin Institute of Technology | Wang K.,Northeast Normal University
Journal of Biological Systems | Year: 2011

Stochastic cooperation model of two species with generalized dose-response function in a polluted environment is studied. Sufficient criteria for extinction, non-persistence in the mean, weak persistence in the mean, strong persistence in the mean and stochastic persistence are established. The threshold between weak persistence in the mean and extinction for each species is obtained. Certain long-run-average limits of the solutions are represented by two constants in some cases. The results also reveal that both the stochastic noises and the dose-response function play important roles in determining the persistence or extinction of the species. © 2011 World Scientific Publishing Company.

Liu M.,Harbin Institute of Technology | Wang K.,Harbin Institute of Technology | Wang K.,Northeast Normal University
Journal of Theoretical Biology | Year: 2010

A new single-species model disturbed by both white noise and colored noise in a polluted environment is developed and analyzed. Sufficient criteria for extinction, stochastic nonpersistence in the mean, stochastic weak persistence in the mean, stochastic strong persistence in the mean and stochastic permanence of the species are established. The threshold between stochastic weak persistence in the mean and extinction is obtained. The results show that both white and colored environmental noises have sufficient effect to the survival results. © 2010 Elsevier Ltd.

Liu M.,Harbin Institute of Technology | Wang K.,Harbin Institute of Technology | Wang K.,Northeast Normal University
Journal of Theoretical Biology | Year: 2010

This is a continuation of our paper [Liu, M., Wang, K., 2010. Persistence and extinction of a stochastic single-specie model under regime switching in a polluted environment, J. Theor. Biol. 264, 934-944]. Taking both white noise and colored noise into account, a stochastic single-species model under regime switching in a polluted environment is studied. Sufficient conditions for extinction, stochastic nonpersistence in the mean, stochastic weak persistence and stochastic permanence are established. The threshold between stochastic weak persistence and extinction is obtained. The results show that a different type of noise has a different effect on the survival results. © 2010 Elsevier Ltd.

Wang Y.,Northeast Normal University | Bi X.,Northeast Normal University | Bi X.,Nankai University | Li W.-Q.,Harbin Institute of Technology | And 4 more authors.
Organic Letters | Year: 2011

A novel iron-catalyzed aminolysis of β-carbonyl 1,3-dithianes with various amines including ammonia, primary and secondary amines, as well as hydrazine hydrate has been developed, leading to the synthesis of stereodefined β-enaminones and 3,4-disubstituted pyrazoles in good to high yields. © 2011 American Chemical Society.

Liu M.,Harbin Institute of Technology | Wang K.,Harbin Institute of Technology | Wang K.,Northeast Normal University | Wu Q.,Harbin Institute of Technology
Bulletin of Mathematical Biology | Year: 2011

Stochastic competitive models with pollution and without pollution are proposed and studied. For the first system with pollution, sufficient criteria for extinction, nonpersistence in the mean, weak persistence in the mean, strong persistence in the mean, and stochastic permanence are established. The threshold between weak persistence in the mean and extinction for each population is obtained. It is found that stochastic disturbance is favorable for the survival of one species and is unfavorable for the survival of the other species. For the second system with pollution, sufficient conditions for extinction and weak persistence are obtained. For the model without pollution, a partial stochastic competitive exclusion principle is derived. © 2010 Society for Mathematical Biology.

Zou X.,Harbin Institute of Technology | Wang K.,Harbin Institute of Technology | Wang K.,Northeast Normal University
Nonlinear Analysis: Hybrid Systems | Year: 2014

The optimization problem of fishing for a stochastic logistic model is studied in this paper. Besides a standard geometric Brownian motion, another two driving processes are taken into account: a stationary Poisson point process and a continuous-time finite-state Markov chain. The classical harvesting problem for this model is a big difficult puzzle since the corresponding Fokker-Planck equations with three types of noise are very difficult to solve. Our main goal of this paper is to work out the optimization problem with respect to stationary probability density. One of the main contributions is to provide a new equivalent approach to overcome this problem. More precisely, an ergodic method is used to show the almost surely equivalency between the time averaging yield and sustainable yield. Results show that the optimal strategy changes with environment. An interesting thing is that the optimal strategy for each state is equivalent to the global optimality. © 2014 Elsevier Ltd.

Hu G.,Harbin Institute of Technology | Wang K.,Harbin Institute of Technology | Wang K.,Northeast Normal University
Computers and Mathematics with Applications | Year: 2011

This paper focuses on the method of the simulation of a stochastic system and the main method of our paper is the Monte Carlo computation simulation method. Taking the stochastic Logistic equation as an example, we present the simulation of the sample trajectory by Euler scheme and the invariant probability distribution of stochastic differential equations with the Monte Carlo method. We also compare the simulation result with the analytical result for the autonomous stochastic Logistic model. Moreover, the stochastic Logistic equation with Markovian switching which is described by a Markov chain taking values in a finite state space is considered. © 2011 Elsevier Ltd. All rights reserved.

Liu M.,Harbin Institute of Technology | Wang K.,Harbin Institute of Technology | Wang K.,Northeast Normal University
Mathematical and Computer Modelling | Year: 2011

Taking both white noise and colored environmental noise into account, a general stochastic logistic model under regime switching is proposed and studied. Sufficient conditions for extinction, nonpersistence in the mean, weak persistence, stochastic permanence and global attractivity are established. The critical number between weak persistence and extinction is obtained. Moreover, some simulation figures are introduced to illustrate the main results. © 2011 Elsevier Ltd.

Wu J.-H.,Northeast Normal University | Artoni M.,European Laboratory for Nonlinear Spectroscopy | Artoni M.,University of Brescia | La Rocca G.C.,Normal School of Pisa
Physical Review Letters | Year: 2014

Light propagation in optical lattices of driven cold atoms exhibits non-Hermitian degeneracies when the first-order modulation amplitudes of real and imaginary parts of the probe susceptibility are manipulated to be balanced. At these degeneracies, one may observe complete unidirectional reflectionless light propagation. This strictly occurs with no gain and can be easily tuned and fully reversed as supported by the transfer-matrix calculations and explained via a coupled-mode analysis. © 2014 American Physical Society.

Zhao T.,Harbin Institute of Technology | Ran Q.,Harbin Institute of Technology | Chi Y.,Northeast Normal University
Optics Communications | Year: 2014

Recently, optical asymmetric cryptosystem (OACS) has became the focus of discussion and concern of researchers. Some researchers pointed out that OACS was not tenable because of misunderstanding the concept of asymmetric cryptosystem (ACS). We propose an improved cryptosystem using RSA public-key algorithm based on existing OACS and the new system conforms to the basic agreement of public key cryptosystem. At the beginning of the encryption process, the system will produce an independent phase matrix and allocate the input image, which also conforms to one-time pad cryptosystem. The simulation results show that the validity of the improved cryptosystem and the high robustness against attack scheme using phase retrieval technique. © 2014 Elsevier B.V. All rights reserved.

Liu M.,Harbin Institute of Technology | Wang K.,Harbin Institute of Technology | Wang K.,Northeast Normal University
Mathematical and Computer Modelling | Year: 2012

This is a continuation of our paper [M. Liu, K. Wang, Asymptotic properties and simulations of a stochastic logistic model under regime switching, Math. Comput. Modelling 54 (2011) 2139-2154]. First, we establish the sufficient conditions for stochastic permanence which are much weaker than those in our previous paper. Then we study some new asymptotic properties of this model. The lower-growth rate and the upper-growth rate of the positive solution are investigated. The superior limit of the average in time of the sample path of the solution is also estimated. Finally, some simulation figures are introduced to illustrate the main results. Some recent investigations are improved and generalized. © 2011 Elsevier Ltd.

Tang Q.,Northeast Normal University | Liu S.,Northeast Normal University | Liu Y.,Northeast Normal University | He D.,Northeast Normal University | And 5 more authors.
Inorganic Chemistry | Year: 2014

Isostructural lanthanide metal-organic frameworks (MOFs) are synthesized through the spontaneous self-assembly of H3BTPCA (1,1′, 1″-(benzene-1,3,5-triyl)tripiperidine-4-carboxylic acid) ligands and lanthanide ions (we term these MOFs Ln-BTPCA, Ln = La3+, Tb 3+, Sm3+, etc.). Prompted by the observation that the different lanthanide ions have identical coordination environment in these MOFs, we explored and succeeded in the preparation of mixed-lanthanide analogues of the single-lanthanide MOFs by way of in situ doping using a mixture of lanthanide salts. With careful adjustment of the relative concentration of the lanthanide ions, the color of the luminescence can be modulated, and white light-emission can indeed be achieved. The mechanisms possibly responsible for the observed photophysical properties of these mixed-lanthanide MOFs are also discussed. © 2013 American Chemical Society.

Guan Y.,Harbin Institute of Technology | Wang K.,Harbin Institute of Technology | Wang K.,Northeast Normal University
Mathematical and Computer Modelling | Year: 2013

In this paper, we study the structure of time scales under translations. We define several kinds of time scales such as the two-way translation invariant time scale and investigate their properties. Then we develop the almost periodic function theory on time scales, with examples given along the way. © 2012 Elsevier Ltd.

Zou X.,Harbin Institute of Technology | Wang K.,Harbin Institute of Technology | Wang K.,Northeast Normal University
Nonlinear Analysis: Real World Applications | Year: 2011

Many species are endangered, if we do not act fast, we are going to lose them forever. Establishing protection zone is widely used to protect endangered species. How is the effect of this method? What factors affect the effect of the protection zone? We study this topic by a new mathematical model. We examine the effect of the protection zone and conclude that the protection zone is effective for conservation of population resources and ecological environment, though in some cases the extinction cannot be eliminated. The dangerous region, the parameters domains and the typical bifurcation curves of stability of steady states for the considered system are determined. Our results provide theoretical evidence for the practical management of biological resources. © 2010 Elsevier Ltd. All rights reserved.

Li W.,Harbin Institute of Technology | Su H.,Harbin Institute of Technology | Wang K.,Harbin Institute of Technology | Wang K.,Northeast Normal University
Automatica | Year: 2011

This paper considers the global stability problem for some stochastic coupled systems on networks (SCSNs). We provide a systematic method for constructing a global Lyapunov function for these SCSNs, by using graph theory and the Lyapunov second method. Consequently, a new global stability principle, which has a close relation to the topology property of the network, is given. As an application to the results, we employ the principle to two well-known coupled systems in physical and ecology, and then some easy-verified sufficient conditions which guarantee the global stability are obtained. © 2010 Elsevier Ltd. All rights reserved.

Li W.,Harbin Institute of Technology | Song H.,Harbin Institute of Technology | Qu Y.,Harbin Institute of Technology | Wang K.,Harbin Institute of Technology | Wang K.,Northeast Normal University
Systems and Control Letters | Year: 2013

This paper investigates the global exponential stability of stochastic coupled systems on networks with Markovian switching (SCSNMS). Sufficient conditions are established to guarantee pth moment exponential stability and almost surely exponential stability of the SCSNMS, by using concepts from graph theory and M-matrix into Lyapunov method. Consequently, the upper boundaries of the pth moment Lyapunov exponent and the sample Lyapunov exponent are given. Finally, to illustrate the capabilities of the stability principle, easy-verifiable sufficient conditions of global exponential stability for a stochastic coupled oscillator on network with Markovian switching are obtained. © 2013 Elsevier B.V. All rights reserved.

Zhang H.,Northeast Normal University | Lu Y.,Northeast Normal University | Zhang Z.,Northeast Normal University | Fu H.,Northeast Normal University | And 4 more authors.
Chemical Communications | Year: 2012

A 12-connected metal-organic framework based on an unprecedented cyclic Cu 12 cluster with a large internal cavity has been prepared, and its cation exchange property was determined. © 2012 The Royal Society of Chemistry.

Su H.,Harbin Institute of Technology | Li W.,Harbin Institute of Technology | Wang K.,Harbin Institute of Technology | Wang K.,Northeast Normal University
Chaos | Year: 2012

This paper is concerned with the global stability for a general discrete-time coupled system on network (DTCSN). A systematic method of constructing global Lyapunov function for the DTCSN is provided by combining graph theory and the Lyapunov method. Consequently, some novel global stability principles, which have close relation to the topology property of the network, are given. They have important leading significance in the design and applications for the globally stable DTCSNs. In addition, to present the effectiveness and applicability of the results, the proposed theory is used to analyze the global stability for some practical models and numerical methods. © 2012 American Institute of Physics.

Su S.-L.,Harbin Institute of Technology | Shao X.-Q.,Northeast Normal University | Wang H.-F.,Yanbian University | Zhang S.,Harbin Institute of Technology | Zhang S.,Yanbian University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

We propose a dissipative scheme to generate a maximally entangled state for two Λ-type atoms trapped in an optical cavity. Different from the unitary-dynamics-based scheme, our work shows that both atomic spontaneous emission and cavity decay are no longer detrimental, but necessary for entanglement generation. The scheme is independent of initial states and does not require precise time control. A final numerical simulation with two groups of experimental parameters indicates that the present scheme is feasible and the performance could be better than the unitary-dynamics-based scheme. © 2014 American Physical Society.

Li Y.,Northeast Normal University | Li Y.,ETH Zurich | Li Z.,ETH Zurich | Xiong T.,Northeast Normal University | And 2 more authors.
Organic Letters | Year: 2012

A novel Selectfluor-mediated copper-catalyzed highly selective benzylic C-O cyclization for the synthesis 4H-3,1-benzoxazines is reported. The predominant selectivity for a benzylic C(sp 3)-H over an aromatic C(sp 2)-H bond in N-o-tolylbenzamides is achieved. © 2012 American Chemical Society.

Zhao S.,Key Laboratory of Polyoxometalate Science | Wang X.,Key Laboratory of Polyoxometalate Science | Huo M.,Northeast Normal University
Applied Catalysis B: Environmental | Year: 2010

Micellar molybdovanadophosphoric polyoxometalate (POM) catalysts [(CnH2n+1)N(CH3)3]3+xPVxMo12-xO40 (x = 1, 2, 3; n = 8, 12, 14, 16, 18) were prepared and used for catalytic wet air oxidation (CWAO) of phenol. X-ray photoelectron spectrum (XPS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) were used to characterize the resulting samples. The best catalytic activity was obtained over (C16TA)6PV3Mo9O40, which showed 95.3% degradation efficiency, 98.5% COD removal and 93.0% TOC reduction with air under room condition toward complete degradation product CO2 within 90 min. The leaching test showed that the POM micellar catalysts have an excellent stability and can be used as heterogeneous catalysts for about six times. © 2010 Elsevier B.V. All rights reserved.

Ba X.,University of Texas Medical Branch | Ba X.,Northeast Normal University | Garg N.J.,University of Texas Medical Branch
American Journal of Pathology | Year: 2011

Poly(ADP-ribosyl)ation, attaching the ADP-ribose polymer chain to the receptor protein, is a unique posttranslational modification. Poly(ADP-ribose) polymerase-1 (PARP-1) is a well-characterized member of the PARP family. In this review, we provide a general update on molecular structure and structure-based activity of this enzyme. However, we mainly focus on the roles of PARP-1 in inflammatory diseases. Specifically, we discuss the signaling pathway context that PARP-1 is involved in to regulate the pathogenesis of inflammation. PARP-1 facilitates diverse inflammatory responses by promoting inflammation-relevant gene expression, such as cytokines, oxidation-reduction - related enzymes, and adhesion molecules. Excessive activation of PARP-1 induces mitochondria- associated cell death in injured tissues and constitutes another mechanism for exacerbating inflammation. Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Liu H.-S.,Northeast Normal University | Liu H.-S.,Daqing Normal University | Lan Y.-Q.,Northeast Normal University | Li S.-L.,Northeast Normal University
Crystal Growth and Design | Year: 2010

Two novel metal-organic frameworks [Ni7(H2O) 6L2(O)2](Cl)2(NO3) 2•6(H2O)•(Emim)2 (1) and [Ni 2(H2O)2L]•7(H2O) (2) have been successfully constructed by using ionothermal and hydrothermal synthesis, respectively. Compound 1 represents the new type metal-organic replicate of PoCl2 with the scu net containing an eight-connecting polynuclear cluster and a large four-connecting complex. Compound 2 showing a one-dimensional chain has been separated in a traditional hydrothermal method using similar starting materials. By inspection of the structures of 1 and 2, it is believed that the different reaction conditions play important roles in forming the final structures. In addition, we investigated the optical band gap of compound 1. © 2010 American Chemical Society.

Han D.-D.,Jilin Institute of Chemical Technology | Han D.-D.,Northeast Normal University | Lu D.-Y.,Jilin Institute of Chemical Technology | Sun X.-Y.,Jilin Institute of Chemical Technology
Journal of Alloys and Compounds | Year: 2013

The influence of donor and acceptor co-doping on structure and dielectric properties of (Ba1-xNdx) (Ti1-yFe y)O3 (BNTF) (x = 0.05, y = 0.01-0.07; and x = 0-0.08, y = 0.05) ceramics was investigated with X-ray diffraction (XRD), scanning electron microscopy (SEM), electron paramagnetic resonance (EPR), Raman spectroscopy, and dielectric measurements. When x < y, two types of Nd3+ - Fe 3+ and Fe3+ - VO - Fe3+ defect complexes formed and could not coexist, leading to the mixed phases of cubic and hexagonal. A single-phase ceramic with a cubic or tetragonal structure formed for x ≥ y and the dielectric-peak temperature (Tm) in BNTF with x = 0.05 decreased linearly with increasing y at a rate of -5 °C/mol% Fe ions. A high-k Y5V behavior can be realized at x = y = 0.05 (i.e., C-N5F5). The same concentrations of Nd3+ and Fe3+ formed Nd3+ - Fe3+ complexes, which could effectively suppress the dielectric loss and silence the 840 cm-1 band called "Raman charge effect" associated with Nd3+ donors. C-N5F5 exhibited a cubic structure, medium-sized grains (3.3 μm), low dielectric loss (<0.06), and high-k Y5V behavior (ε′RT = 6790). Defect chemistry associated with structure evolution is discussed. © 2013 Elsevier B.V. All rights reserved.

Zhang Z.-M.,Northeast Normal University | Yao S.,Changchun University of Science and Technology | Li Y.-G.,Northeast Normal University | Wu H.-H.,Northeast Normal University | And 7 more authors.
Chemical Communications | Year: 2013

A polyoxometalate (POM)-based {MnIV 2Mn III 6MnII 4} complex with single-molecule magnet (SMM) behaviour was prepared, exhibiting the largest known Mn nuclearity and the most Mn valence states in the POM-based SMM family. © 2013 The Royal Society of Chemistry.

Yang Y.,Northeast Normal University | Yang Y.,Jilin Institute of Chemical Technology | Xu L.,Northeast Normal University | Li F.,Northeast Normal University | And 2 more authors.
Journal of Materials Chemistry | Year: 2010

A photovoltaic electrode material consisting of cobalt tetraaminophthalocyanine (CoTAPc) and Dawson-type phosphomolybdate (P 2Mo 18) was fabricated through the layer-by-layer (LbL) assembly method. The film electrode was characterized by UV-vis spectroscopy, IR spectroscopy, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and photoelectrochemical measurements. Photovoltaic measurement of the film electrode under light irradiation of 365 nm demonstrated that the P 2Mo 18/CoTAPc composite film electrode exhibits higher photocurrent and power conversion efficiency (η) than the phthalocyanine-only electrode, furthermore the increased photocurrent of (P 2Mo 18/CoTAPc/PSS/PAH) 5 is not equal to the direct photoresponse addition of P 2Mo 18 and CoTAPc. Based on the results of fluorescence quenching measurements, the enhanced photovoltaic effect should be attributed to the occurrence of the photoinduced electron transfer between CoTAPc and POM, which increases the efficient dissociation of excited electron-hole pairs (excitons). The present research represents the first example of enhancing the photovoltaic response of organic photovoltaic materials by the assistance of polyoxometalates. © The Royal Society of Chemistry 2010.

Genheden S.,Lund University | Mikulskis P.,Lund University | Hu L.,Lund University | Hu L.,Northeast Normal University | And 3 more authors.
Journal of the American Chemical Society | Year: 2011

Continuum solvation methods are frequently used to increase the efficiency of computational methods to estimate free energies. In this paper, we have evaluated how well such methods estimate the nonpolar solvation free-energy change when a ligand binds to a protein. Three different continuum methods at various levels of approximation were considered, viz., the polarized continuum model (PCM), a method based on cavity and dispersion terms (CD), and a method based on a linear relation to the solvent-accessible surface area (SASA). Formally rigorous double-decoupling thermodynamic integration was used as a benchmark for the continuum methods. We have studied four protein-ligand complexes with binding sites of varying solvent exposure, namely the binding of phenol to ferritin, a biotin analogue to avidin, 2-aminobenzimidazole to trypsin, and a substituted galactoside to galectin-3. For ferritin and avidin, which have relatively hidden binding sites, rather accurate nonpolar solvation free energies could be obtained with the continuum methods if the binding site is prohibited to be filled by continuum water in the unbound state, even though the simulations and experiments show that the ligand replaces several water molecules upon binding. For the more solvent exposed binding sites of trypsin and galectin-3, no accurate continuum estimates could be obtained, even if the binding site was allowed or prohibited to be filled by continuum water. This shows that continuum methods fail to give accurate free energies on a wide range of systems with varying solvent exposure because they lack a microscopic picture of binding-site hydration as well as information about the entropy of water molecules that are in the binding site before the ligand binds. Consequently, binding affinity estimates based upon continuum solvation methods will give absolute binding energies that may differ by up to 200 kJ/mol depending on the method used. Moreover, even relative energies between ligands with the same scaffold may differ by up to 75 kJ/mol. We have tried to improve the continuum solvation methods by adding information about the solvent exposure of the binding site or the hydration of the binding site, and the results are promising at least for this small set of complexes. © 2011 American Chemical Society.

Yang Y.,Northeast Normal University | Yang Y.,Jilin Institute of Chemical Technology | Xu L.,Northeast Normal University | Li F.,Northeast Normal University | Qu X.,Jilin Institute of Chemical Technology
Inorganic Chemistry Communications | Year: 2013

Two novel complexes [H2N(CH2CH2) 2O]4[Na(H2O)2{O(CH 2CH2)2NH2}]2[Na(H 2O)4]2[V10O28][NiMo 6O24H6]·8H2O (1) and [H 2N(CH2CH2)2O]6[Na(H 2O)3]2[V10O28H 2][NiMo6O24H6]·4H 2O (2) containing both isopolyvanadate {V10O28} and [NiMo6O24H6]4 - units have been synthesized and structurally characterized for the first time, showing that the pH value of the reaction plays a key role in structure control of self-assembled processes. Compound 1 exhibits a novel one-dimensional (1-D) chain-like structure consisting of Anderson-type [NiMo6O 24H6]4 - and isopolyvanadate [V 10O28]6 - anions linked by Na+ ions. In compound 2 with the lower pH value, [NiMo6O24H 6]4 - and [V10O28H2] 4 - anions are bridged by [Na2O10] units to form the 2D extended layer. The magnetic properties of 1 and 2 are presented. © 2013 Elsevier B.V.

Lu D.-Y.,Jilin Institute of Chemical Technology | Han D.-D.,Jilin Institute of Chemical Technology | Han D.-D.,Northeast Normal University
Ceramics International | Year: 2013

Nominal (Ba1-xCex)(Ti0.95-x/4Ce 0.05)O3 ceramics were prepared by a solid state reaction method. A complete solid solution called BC3TC5 was formed only at x=0.03, with a single-phase perovskite structure. The structural and dielectric properties of BC3TC5 were investigated by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, electron paramagnetic resonance, and dielectric measurements. BC3TC5 exhibited a cubic structure and a non-uniform microstructure. Ti-vacancy defects exist in BC3TC5, which has a feature of mixed valence of Ba-site Ce3+ and Ti-site Ce4+. The amphoteric Ce3+/Ce4+ ions can induce an in-situ diffuse phase transition at the Curie point of BaTiO3 (TC=125 C). BC3TC5 exhibits a high-k behavior (ε′m=9470) and low dielectric loss (tan δ<0.025). © 2013 Elsevier Ltd and Techna Group S.r.l.

Lu D.-Y.,Jilin Institute of Chemical Technology | Zhang L.,Jilin Institute of Chemical Technology | Zhang L.,Northeast Normal University | Sun X.-Y.,Jilin Institute of Chemical Technology
Ceramics International | Year: 2013

The influence of the sintering temperature (Ts) on the structure, dielectric and valence-state properties of (Ba1-xEu x)TiO3 (x=0.05) ceramics was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), electron paramagnetic resonance (EPR), Raman spectroscopy, and dielectric temperature measurements. An increase in Ts can increase the solubility limit of Eu in BaTiO 3. When the Ts was increased to 1450 °C, a high-k 'Y5V' (ε′RT=8500) ceramic (C-BE5T) with a single-phase cubic structure was obtained. The dielectric peak shifted rapidly toward lower temperatures with increasing Ts at a rate of -0.46 °C/K. A symmetric (200) XRD peak, exaggerated grain growth (5.6 μm), a mixed valence of Eu2+/Eu3+, an asymmetric main Raman band at 2494 cm-1 and a weak sharp band at 1516 cm-1 in the high-wavenumber region are characteristics of cubic symmetry of C-BE5T. The formation of a solid solution of C-BE5T and defect chemistry are discussed. © 2013 Elsevier Ltd and Techna Group S.r.l.

Zhang L.,Northeast Normal University | Xu X.,Northeast Normal University | Shao Q.-R.,Shunde Entry Exit Inspection and Quarantine Bureau Chemical Products Laboratory | Pan L.,Northeast Normal University | Liu Q.,Northeast Normal University
Organic and Biomolecular Chemistry | Year: 2013

A new reaction model, tandem Michael addition/formal isocyanide insertion into the acyl C-C bond, has been developed. Thus, a series of 2-acylpyrroles and seven-/eight-membered ring fused pyrroles were synthesized from the reaction of methyl isocyanides with enones in a single operation. © 2013 The Royal Society of Chemistry.

Lu D.-Y.,Jilin Institute of Chemical Technology | Cui S.-Z.,Jilin Institute of Chemical Technology | Cui S.-Z.,Northeast Normal University
Journal of the European Ceramic Society | Year: 2014

The point defects and the structural and dielectric properties of Dy-doped BaTiO3 ceramics prepared at 1400°C were investigated. The solubility of Dy in the self-compensation mode was determined to be x=0.07 for (Ba1-xDyx)(Ti1-xDyx)O3, and no EPR signals associated with the Dy3+ Kramers ion or the Ba and Ti vacancies were detected using the electron paramagnetic resonance (EPR) technique. As x increases, the dielectric behavior changed from a first-order phase transition to a diffuse phase transition to a Y7R dielectric-temperature stability. A strong EPR signal at g=1.974, which is rare among rare-earth-doped BaTiO3 ceramics appeared unexpectedly in the single-phase (Ba1-xDyx)Ti1-x/4O3 ceramics with deliberately designed Ti vacancies. This signal was attributed to ionized Ba vacancy defects. A preference for the self-compensation mode of Dy3+ ions is responsible for the appearance of Ba vacancies. The real formula of the nominal (Ba1-xDyx)Ti1-x/4O3 is expressed as (Ba1-xDy3x/4)(Ti1-x/4Dyx/4)O3. In addition, the defect chemistry is discussed. © 2014 Elsevier Ltd.

Luo Y.-H.,Northeast Normal University | Yu X.-Y.,Northeast Normal University | Yu X.-Y.,Jilin Institute of Chemical Technology | Zhang H.,Northeast Normal University
CrystEngComm | Year: 2014

Two novel entangled POM-based coordination polymers (CPs), namely [Co 2(L)5(H2O)2(SiW12O 40)] (1) and [Cu2(L)3(H2O) 2(SiW12O40)]·H2O (2) (L = 4,4′-bis((1H-1,2,4-triazol-1-yl)methyl)biphenyl), have been hydrothermally synthesized. Compound 1 presents an unprecedented 2D + 2D → 3D polypseudorotaxane motif. The fascinating self-catenated framework of compound 2 contains three types of helical chains. In addition, the photocatalytic properties of compounds 1 and 2 have also been investigated. This journal is © the Partner Organisations 2014.

Sun Y.,Northeast Normal University | Xia B.S.,University of Helsinki
Scientometrics | Year: 2016

Citation counts can be used as a proxy to study the scholarly communication of knowledge and the impact of research in academia. Previous research has addressed several important factors of citation counts. In this study, we aim to investigate whether there exist quantitative patterns behind citations, and thus provide a detailed analysis of the factors behind successful research. The study involves conducting quantitative analyses on how various features, such as the author’s quality, the journal’s impact factor, and the publishing year, of a published scientific article affect the number of citations. We carried out full-text searches in Google Scholar to obtain our data set on citation counts. The data set is then set up into panels and used to conduct the proposed analyses by employing a negative binomial regression. Our results show that attributes such as the author’s quality and the journal’s impact factor do have important contributions to its citations. In addition, an article’s citation count does not only depend on its own properties as mentioned above but also depends on the quality, as measured by the number of citations, of its cited articles. That is, the number of citations of a paper seems to be affected by the number of citations of articles that the particular paper cites. This study provides statistical characteristics of how different features of an article affect the number of citations. In addition, it provides statistical evidence that the number of citations of a scientific article depends on the number of citations of the articles it cites. © 2016 Akadémiai Kiadó, Budapest, Hungary

Tang X.-D.,Capital Normal University | Tang X.-D.,Northeast Normal University | Liao Y.,Capital Normal University | Liao Y.,Northeast Normal University | And 4 more authors.
Journal of Materials Chemistry | Year: 2012

The bridging effect on the charge transport properties of cyclooctatetrathiophene and its derivatives (systems 1-4) was investigated at the level of density functional theory (DFT). Insights into their geometries, frontier molecular orbitals, reorganization energies, transfer integrals and band structures were provided in detail. Increasing charge mobilities for both holes and electrons were predicted in cyclooctatetrathiophene derivatives as the number of bridging sulfur atoms increased. The improved charge transport from system 1 to 4 can be interpreted from two contributions: (i) decreased reorganization energy with improved molecular planarity under the consideration of intermolecular interactions; and (ii) enhanced transfer integral derived from the π-stacking arrangement for 2 and 3, and multidimensional S⋯S interactions are found to contribute to charge transport in system 4 besides π⋯π interactions. The charge transport properties were also analyzed with a band-like model and the results were in agreement with those gained from the hopping model in the fact that the paths with large transfer integrals are all along the directions with large dispersions in the valence band or conduction band. © The Royal Society of Chemistry 2012.

Zhang M.,Northeast Normal University | Zhang M.,Jilin Agricultural University | Xu C.,Northeast Normal University | von Wettstein D.,Washington State University | Liu B.,Northeast Normal University
Plant Physiology | Year: 2011

It has been well established that DNA cytosine methylation plays essential regulatory roles in imprinting gene expression in endosperm, and hence normal embryonic development, in the model plant Arabidopsis (Arabidopsis thaliana). Nonetheless, the developmental role of this epigenetic marker in cereal crops remains largely unexplored. Here, we report for sorghum (Sorghum bicolor) differences in relative cytosine methylation levels and patterns at 5'-CCGG sites in seven tissues (endosperm, embryo, leaf, root, young inflorescence, anther, and ovary), and characterize a set of tissue-specific differentially methylated regions (TDMRs). We found that the most enriched TDMRs in sorghum are specific for the endosperm and are generated concomitantly but imbalanced by decrease versus increase in cytosine methylation at multiple 5'-CCGG sites across the genome. This leads to more extensive demethylation in the endosperm than in other tissues, where TDMRs are mainly tissue nonspecific rather than specific to a particular tissue. Accordingly, relative to endosperm, the other six tissues showed grossly similar levels though distinct patterns of cytosine methylation, presumably as a result of a similar extent of concomitant decrease versus increase in cytosine methylation that occurred at variable genomic loci. All four tested TDMRs were validated by bisulfite genomic sequencing. Diverse sequences were found to underlie the TDMRs, including those encoding various known-function or predicted proteins, transposable elements, and those bearing homology to putative imprinted genes in maize (Zea mays). We further found that the expression pattern of at least some genic TDMRs was correlated with its tissuespecific methylation state, implicating a developmental role of DNA methylation in regulating tissue-specific or -preferential gene expression in sorghum. © 2011 American Society of Plant Biologists.

Shabala L.,University of Tasmania | Mackay A.,University of Tasmania | Tian Y.,Northeast Normal University | Jacobsen S.-E.,Copenhagen University | And 2 more authors.
Physiologia Plantarum | Year: 2012

Two components of salinity stress are a reduction in water availability to plants and the formation of reactive oxygen species. In this work, we have used quinoa (Chenopodium quinoa), a dicotyledonous C3 halophyte species displaying optimal growth at approximately 150 mM NaCl, to study mechanisms by which halophytes cope with the afore-mentioned components of salt stress. The relative contribution of organic and inorganic osmolytes in leaves of different physiological ages (e.g. positions on the stem) was quantified and linked with the osmoprotective function of organic osmolytes. We show that the extent of the oxidative stress (UV-B irradiation) damage to photosynthetic machinery in young leaves is much less when compared with old leaves, and attribute this difference to the difference in the size of the organic osmolyte pool (1.5-fold difference under control conditions; sixfold difference in plants grown at 400 mM NaCl). Consistent with this, salt-grown plants showed higher Fv/Fm values compared with control plants after UV-B exposure. Exogenous application of physiologically relevant concentrations of glycine betaine substantially mitigated oxidative stress damage to PSII, in a dose-dependent manner. We also show that salt-grown plants showed a significant (approximately 30%) reduction in stomatal density observed in all leaves. It is concluded that accumulation of organic osmolytes plays a dual role providing, in addition to osmotic adjustment, protection of photosynthetic machinery against oxidative stress in developing leaves. It is also suggested that salinity-induced reduction in stomatal density represents a fundamental mechanism by which plants optimize water use efficiency under saline conditions. © 2012 Physiologia Plantarum.

Hariadi Y.,University of Tasmania | Hariadi Y.,University of Jember | Marandon K.,Polytechnic Institute of LaSalle Beauvais | Tian Y.,Northeast Normal University | And 2 more authors.
Journal of Experimental Botany | Year: 2011

Ionic and osmotic relations in quinoa (Chenopodium quinoa Willd.) were studied by exposing plants to six salinity levels (0-500mM NaCl range) for 70d. Salt stress was administered either by pre-mixing of the calculated amount of NaCl with the potting mix before seeds were planted or by the gradual increase of NaCl levels in the irrigation water. For both methods, the optimal plant growth and biomass was achieved between 100mM and 200mM NaCl, suggesting that quinoa possess a very efficient system to adjust osmotically for abrupt increases in NaCl stress. Up to 95% of osmotic adjustment in old leaves and between 80% and 85% of osmotic adjustment in young leaves was achieved by means of accumulation of inorganic ions (Na+, K+, and Cl -) at these NaCl levels, whilst the contribution of organic osmolytes was very limited. Consistently higher K+ and lower Na+ levels were found in young, as compared with old leaves, for all salinity treatments. The shoot sap K+ progressively increased with increased salinity in old leaves; this is interpreted as evidence for the important role of free K+ in leaf osmotic adjustment under saline conditions. A 5-fold increase in salinity level (from 100mM to 500mM) resulted in only a 50% increase in the sap Na+ content, suggesting either a very strict control of xylem Na+ loading or an efficient Na+ removal from leaves. A very strong correlation between NaCl-induced K+ and H+ fluxes was observed in quinoa root, suggesting that a rapid NaCl-induced activation of H+-ATPase is needed to restore otherwise depolarized membrane potential and prevent further K+ leak from the cytosol. Taken together, this work emphasizes the role of inorganic ions for osmotic adjustment in halophytes and calls for more in-depth studies of the mechanisms of vacuolar Na+ sequestration, control of Na+ and K+ xylem loading, and their transport to the shoot. © 2010 The Author.

Han Y.,Northeast Normal University | Han Y.,University of Rhode Island | Wang Y.,Northeast Normal University | Wang Y.,University of Rhode Island | Zhao Y.,Northeast Normal University
IEEE Transactions on Geoscience and Remote Sensing | Year: 2010

Soil moisture is an important indicator of the land surface environment. The combination of land surface temperature (LST) and normalized difference vegetation index (NDVI) could enhance the ability of extracting information on soil moisture conditions. In this study, we employed multitemporal Moderate Resolution Imaging Spectroradiometer (MODIS) data products of LST, NDVI, and land cover types to obtain the information about soil moisture for the greater Changbai Mountains. We selected nine time periods in 2007 for inversion of the soil moisture conditions and focused the analysis on four critical time periods. According to the spatial pattern of the LST and NDVI, we established the wet-edge and dry-edge equations and determined the relative parameters. We obtained the temperaturevegetation dryness index (TVDI) using the wet-edge and dry-edge relationships to reveal temporal changes of the land surface soil moisture conditions of the study area. We also analyzed the relationship between different land cover types in five TVDI classes. This paper demonstrates that TVDI is an effective indicator to detect soil moisture status in the greater Changbai Mountains region. © 2006 IEEE.

Ubierna N.,Washington State University | Ubierna N.,Australian National University | Sun W.,Washington State University | Sun W.,Northeast Normal University | And 2 more authors.
Plant, Cell and Environment | Year: 2013

The efficiency of C4 photosynthesis in Zea mays, Miscanthus x giganteus and Flaveria bidentis in response to light was determined using measurements of gas exchange, 13CO2 photosynthetic discrimination, metabolite pools and spectroscopic assays, with models of C4 photosynthesis and leaf 13CO2 discrimination. Spectroscopic and metabolite assays suggested constant energy partitioning between the C4 and C3 cycles across photosynthetically active radiation (PAR). Leakiness (φ), modelled using C4 light-limited photosynthesis equations (φmod), matched values from the isotope method without simplifications (φis) and increased slightly from high to low PAR in all species. However, simplifications of bundle-sheath [CO2] and respiratory fractionation lead to large overestimations of φ at low PAR with the isotope method. These species used different strategies to maintain similar φ. For example, Z.mays had large rates of the C4 cycle and low bundle-sheath cells CO2conductance (gbs). While F.bidentis had larger gbs but lower respiration rates and M.giganteus had less C4 cycle capacity but low gbs, which resulted in similar φ. This demonstrates that low gbs is important for efficient C4 photosynthesis but it is not the only factor determining φ. Additionally, these C4 species are able to optimize photosynthesis and minimize φ over a range of PARs, including low light. © 2012 Blackwell Publishing Ltd.

Yang C.,Northeast Normal University | Zhao L.,Northeast Normal University | Zhang H.,Northeast Normal University | Yang Z.,Northeast Normal University | And 7 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2014

Hexaploid bread wheat (Triticum aestivum L., genome BBAADD) is generally more salt tolerant than its tetraploid wheat progenitor (Triticum turgidum L.). However, little is known about the physiological basis of this trait or about the relative contributions of allohexaploidization and subsequent evolutionary genetic changes on the trait development. Here, we compared the salt tolerance of a synthetic allohexaploid wheat (neo-6x) with its tetraploid (T. turgidum; BBAA) and diploid (Aegilops tauschii; DD) parents, as well as a natural hexaploid bread wheat (nat-6x). We studied 92 morphophysiological traits and analyzed homeologous gene expression of a major salt-tolerance gene High-Affinity K+ Transporter 1;5 (HKT1;5). We observed that under salt stress, neo-6x exhibited higher fitness than both of its parental genotypes due to inheritance of favorable traits like higher germination rate from the 4x parent and the stronger root Na+ retention capacity from the 2x parent. Moreover, expression of the D-subgenome HKT1;5 homeolog, which is responsible for Na+ removal from the xylem vessels, showed an immediate transcriptional reprogramming following allohexaploidization, i.e., from constitutive high basal expression in Ae. tauschii (2x) to salt-induced expression in neo-6x. This phenomenon was also witnessed in the nat-6x. An integrated analysis of 92 traits showed that, under salt-stress conditions, neo-6x resembled more closely the 2x than the 4x parent, suggesting that the salt stress induces enhanced expressivity of the D-subgenome homeologs in the synthetic hexaploid wheat. Collectively, the results suggest that condition-dependent functionalization of the subgenomes might have contributed to the wide-ranging adaptability of natural hexaploid wheat.

Zhang H.,Northeast Normal University | Bian Y.,Northeast Normal University | Gou X.,Northeast Normal University | Dong Y.,Northeast Normal University | And 8 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2013

Polyploidy or whole-genome duplication is recurrent in plant evolution, yet only a small fraction of whole-genome duplications has led to successful speciation. A major challenge in the establishment of nascent polyploids is sustained karyotype instability, which compromises fitness. The three putative diploid progenitors of bread wheat, with AA, SS (S ~ B), and DD genomes occurred sympatrically, and their cross-fertilization in different combinations may have resulted in fertile allotetraploids with various genomic constitutions. However, only SSAA or closely related genome combinations have led to the speciation of tetraploid wheats like Triticum turgidum and Triticum timopheevii. We analyzed early generations of four newly synthesized allotetraploid wheats with genome compositions SshSshAmAm, SlSlAA, SbSbDD, and AADD by combined fluorescence and genomic in situ hybridization- based karyotyping. Results of karyotype analyses showed that although SshS shAmAm and SlSlAA are characterized by immediate and persistent karyotype stability, massive aneuploidy and extensive chromosome restructuring are associated with S bSbDD and AADD in which parental subgenomes showed markedly different propensities for chromosome gain/loss and rearrangements. Although compensating aneuploidy and reciprocal translocation between homeologs prevailed, reproductive fitness was substantially compromised due to chromosome instability. Strikingly, localized genomic changes in repetitive DNA and copy-number variations in gene homologs occurred in both chromosome stable lines, SshSshAmAm and S lSlAA. Our data demonstrated that immediate and persistent karyotype stability is intrinsic to newly formed allotetraploid wheat with genome combinations analogous to natural tetraploid wheats. This property, coupled with rapid gene copy-number variations, may have laid the foundation of tetraploid wheat establishment.

Liu S.,Northeast Normal University | Liu S.,Henan Polytechnic University | Sun K.,Northeast Normal University | Jiang T.,Northeast Normal University | Feng J.,Northeast Normal University
Journal of Experimental Biology | Year: 2015

When facing the challenges of environmental change, such as habitat fragmentation, organisms have to adjust their phenotype to adapt to various environmental stresses. Recent studies show that epigenetic modifications could mediate environmentally induced phenotypic variation, and this epigenetic variance could be inherited by future generations, indicating that epigenetic processes have potential evolutionary effects. Bats living in diverse environments show geographic variations in phenotype, and the females usually have natal philopatry, presenting an opportunity to explore how environments shape epigenetic marks on the genome and the evolutionary potential of epigenetic variance in bat populations for adaptation. We have explored the natural epigenetic diversity and structure of female populations of the great roundleaf bat (Hipposideros armiger), the least horseshoe bat (Rhinolophus pusillus) and the eastern bent-winged bat (Miniopterus fuliginosus) using a methylation-sensitive amplified polymorphism technique. We have also estimated the effects of genetic variance and ecological variables on epigenetic diversification. All three bat species have a low level of genomic DNA methylation and extensive epigenetic diversity that exceeds the corresponding genetic variance. DNA sequence divergence, epigenetic drift and environmental variables contribute to the epigenetic diversities of each species. Environmentinduced epigenetic variation may be inherited as a result of both mitosis and meiosis, and their potential roles in evolution for bat populations are also discussed in this review. © 2015. Published by The Company of Biologists Ltd | The Journal of Experimental Biology.

Geng Y.,Northeast Normal University | Wang J.,Northeast Normal University | Wu S.,Northeast Normal University | Li H.,Northeast Normal University | And 4 more authors.
Journal of Materials Chemistry | Year: 2011

Seven perylene bisimide derivatives with different molecular packings and intermolecular interactions were investigated in detail within Marcus-Levich-Jortner formalism at the level of density functional theory (DFT). In theory, we further proved the report that different halogen substitutions in the core position of perylene bisimide lead to different molecular packings in their single crystals and thus obviously different electron transport properties. Here, insight into the geometries, the character of the frontier molecular orbitals, the decompositions of reorganization energies and transfer integrals in different directions was provided to shed light on the relationship between structures and properties. The molecular dynamics (MD) simulations and band structures calculations were also employed to give a multiscale understanding of their transport properties. The results show that there are small discrepancies of the intramolecular electron reorganization energies among these compounds and the transfer integrals determine their electron transport properties. Compounds 1a, 3a and 3b, with typical "brick" packing, π-stacked face-to-face packing and "herringbone" packing, respectively, have larger electron mobilities among these systems and possess different transport dimensionalities. Moreover, we also find there is close relationship between the intermolecular interaction energy and the transfer integral. © The Royal Society of Chemistry.

Sun J.,Northeast Normal University | Wang R.,Northeast Normal University | Wang B.,Wuhan University
Physical Chemistry Chemical Physics | Year: 2011

The mechanism and kinetics of the reaction of acrylonitrile (CH 2=CHCN) with hydroxyl (OH) has been investigated theoretically. This reaction is revealed to be one of the most significant loss processes of acrylonitrile. BHandHLYP and M05-2X methods are employed to obtain initial geometries. The reaction mechanism conforms that OH addition to CC double bond or C atom of -CN group to form the chemically activated adducts, 1-IM1(HOCH 2=CHCN), 2-IM1(CH 2HOCHCN), and 3-IM1(CH 2CHCOHN) via low barriers, and direct hydrogen abstraction paths may also occur. Temperature- and pressure-dependent rate constants have been evaluated using the Rice-Ramsperger-Kassel-Marcus theory. The calculated rate constants are in good agreement with the experimental data. At atmospheric pressure with N 2 as bath gas, 1-IM1(OHCH 2=CHCN) formed by collisional stabilization is the major product in the temperature range of 200-1200 K. The production of CH 2CCN and CHCHCN via hydrogen abstractions becomes dominant at high temperatures (1200-3000 K). © 2011 The Owner Societies.

Chen X.,Center for Advanced Optoelectronic Functional Materials Research | Dai P.,Center for Advanced Optoelectronic Functional Materials Research | Zhang X.,Center for Advanced Optoelectronic Functional Materials Research | Li C.,Center for Advanced Optoelectronic Functional Materials Research | And 4 more authors.
Inorganic Chemistry | Year: 2014

A series of single-phased (Sr3-x,Ca1-y-z,Ba)(PO 4)3Cl (SCBPO-Cl):xEu2+, yTb3+, zMn2+ phosphors were synthesized by high-temperature solid-state reaction, and luminescent properties of these phosphors were investigated by means of photoluminescence and microcathode luminescence (μ-CL). Under UV excitation, white-light emission was obtained from triactivated SCBPO-Cl phosphors via combining three emission bands centered at 450, 543, and 570 nm contributed by Eu2+, Tb3+, and Mn2+, respectively. White-light emission with the three emission bands is further demonstrated in the fluorescence microscope images, CL spectrum, and μ-CL mappings, which strongly confirm that the luminescence distribution of as-prepared SCBPO-Cl:xEu2+, yTb3+, zMn2+ phosphors is very homogeneous. Both spectral overlapping and lifetime decay analyses suggest that dual energy transfers, that is, Eu2+→ Tb3+ and Eu2+→Mn2+, play key roles in obtaining the white emission. The International Commission on Illumination value of white emission as well as luminescence quantum yield (51.2-81.4%) can be tuned by precisely controlling the content of Eu2+, Tb3+, and Mn2+. These results suggest that this single-phased SCBPO-Cl:xEu2+, yTb3+, zMn2+ phosphor may have a potential application as a near-UV convertible white-light emission phosphor for phosphor-converted white light-emitting diode. © 2014 American Chemical Society.

Huang Y.,Iowa State University | Huang Y.,Northeast Normal University | Martin L.M.,Iowa State University | Isbell F.I.,University of Minnesota | Wilsey B.J.,Iowa State University
Basic and Applied Ecology | Year: 2013

Community persistence, or the ability of a community to maintain species composition and diversity through time, is a component of stability that is important to restoration. We ran a biodiversity-ecosystem functioning experiment for three years, and then stopped weeding it for 5-6 years, which allowed us to test whether increased plant species diversity and dissimilarity in height would lead to increased community persistence in the face of high invasion pressure by non-native species. Our approach was unique in that the experiment varied richness (one or four species) and evenness (three levels plus monocultures of the dominant species) using two separate dissimilarity types (having all tall species or having tall and short species combined) in six spatiotemporal blocks. Persistence was quantified as to how well positive productivity-diversity relationships, proportion of planted native species, and species richness remained unchanged over time. Thus, high persistence values indicate low levels of invasion and local extinction. We found that the positive relationship between diversity measures and productivity persisted after cessation of weeding. The proportion of planted species was 32% higher in mixture than in monoculture plots, indicating that monocultures were more heavily invaded by non-native species. Reduced evenness did not affect persistence measures in plots with dissimilar heights, but measures declined linearly with decreased evenness in plots with all tall species. Our results suggest that (1) persistence-diversity relationships are likely to vary with the traits of species becoming rare and going extinct, and (2) it is important to restore higher species diversity in restoration projects to favor the long-term persistence of planted species. © 2013 Gesellschaft fU{double grave}r U{double grave}kologie.

Ma N.-N.,Northeast Normal University | Li S.-J.,Henan Normal University | Yan L.-K.,Northeast Normal University | Qiu Y.-Q.,Northeast Normal University | Su Z.-M.,Northeast Normal University
Dalton Transactions | Year: 2014

The rotary motion based on metallacarboranes around a molecular axis can be controlled by simple electron transfer processes, which provides a basis for the structure-property relationship for the nonlinear optical (NLO) switching. However, this phenomenon has not been previously reported in the development of NLO properties of metallacarboranes. In this work, the metallacarboranes [NiIII/IV(C2B9H11)2] -/0 and their C-,B-functionalized derivatives are studied by the density functional theory (DFT) method. By calculating relative energies, we obtained the stable states before and after rotation controlled by simple electron transfer. Then, the static and frequency-dependent second-order NLO properties were calculated by several DFT functionals. According to the TDDFT results, the large NLO responses of the studied compounds are mainly caused by substituent group-to-carborane cage charge transfer (L′LCT) and substituent group-to-metal charge transfer (L′MCT) processes. The order of first hyperpolarizabilities (β values) illustrates that the NLO response can be enhanced by introducing a strong electron-donating group. Significantly, the geometric interconversions resulting from the redox reaction of 1C/1T-6C/6T allow the NLO responses to be switched "ON" or "OFF". The B(9,9′)-methoxyphenyl-functionalized derivative of nickelacarborane, having low energetic cost and large different NLO responses between two states (from 0 to 20998 a.u.), can be an excellent switchable NLO material. © 2014 The Royal Society of Chemistry.

Shao X.-Q.,Northeast Normal University | Zheng T.-Y.,Northeast Normal University | Zhang S.,Yanbian University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

A scheme is presented for generating steady three-atom singlet states via three V-type atoms interacting with a strongly dissipative two-mode cavity. The local quantum feedback control is applied based on quantum-jump detection to make the target state fidelity as high as possible. This scheme is insensitive to detection inefficiencies since it only delays the time at which stationarity is achieved. Nevertheless, the spontaneous emission plays a negative role in the current system. © 2012 American Physical Society.

Chen Z.,Northeast Normal University | Cao M.,Northeast Normal University | Cao M.,Beijing Institute of Technology | Hu C.,Beijing Institute of Technology
Journal of Physical Chemistry C | Year: 2011

In this work, highly ordered Zn2SnO4 three-dimensional flowerlike superstructures assembled with nanorods have been synthesized by a facile one-step hydrothermal route at 180 °C. The products were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and selected-area electron diffraction. The morphology of the final products was found to depend strongly on the concentrations of EDA and CTAB used. A possible mechanism for the formation of self-assembled Zn2SnO4 flowerlike superstructures is proposed. In addition, the novel Zn2SnO 4 three-dimensional superstructures exhibited good gas-sensing properties that are even better than those of the competing binary metal oxide ±-Fe2O3 and In2O3 sensors. The excellent gas-sensing properties make this material interesting not only for use in sensor devices, but also for a number of related electrochemical applications. © 2011 American Chemical Society.

Chen Z.,Northeast Normal University | Cao M.,Northeast Normal University | Cao M.,Beijing Institute of Technology
Materials Research Bulletin | Year: 2011

Novel Bi2S3 hierarchical nanostructures self-assembled by nanorods are successfully synthesized in mild benzyl alcohol system under hydrothermal conditions. The hierarchical nanostructures exhibit a flower-like shape. X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED) were used to characterize the as-synthesized samples. Meanwhile, the effect of various experimental parameters including the concentration of reagents and reaction time on final product has been investigated. In our experiment, PVP plays an important role for the formation of the hierarchical nanostructures and the possible mechanism was proposed. In addition, Bi2S3 film prepared from the flower-like hierarchical nanostructures exhibits good hydrophobic properties, which may bring nontrivial functionalities and may have some promising applications in the future. © 2010 Elsevier Ltd © 2011 Elsevier Ltd. All rights reserved.

Yin G.,University of Hong Kong | Yin G.,University of Texas M. D. Anderson Cancer Center | Zheng S.,Northeast Normal University | Xu J.,University of Hong Kong
Statistics in Medicine | Year: 2013

Conventional dose-finding methods in oncology are mainly developed for cytotoxic agents with the aim of finding the maximum tolerated dose. In phase I clinical trials with cytostatic agents, such as targeted therapies, designs with toxicity endpoints alone may not work well. For cytostatic agents, the goal is often to find the most efficacious dose that is still tolerable, although these agents are typically less toxic than cytotoxic agents and their efficacy may not monotonically increase with the dose. To effectively differentiate doses for cytostatic agents, we develop a two-stage dose-finding procedure by first identifying the toxicity upper bound of the searching range through dose escalation and then determining the most efficacious dose through dose de-escalation while toxicity is continuously monitored. In oncology, treatment efficacy often takes a relatively long period to exhibit compared with toxicity. To accommodate such delayed response, we model the time to the efficacy event by redistributing the mass of the censored observation to the right and compute the fractional contribution of the censored data. We evaluate the operating characteristics of the new dose-finding design for cytostatic agents and demonstrate its satisfactory performance through simulation studies. © 2012 John Wiley & Sons, Ltd.

Wang J.,Tianjin University of Technology and Education | Wang Y.,Northeast Normal University
International Journal of Geometric Methods in Modern Physics | Year: 2015

The Kastler-Kalau-Walze theorem, announced by A. Connes, shows that the Wodzicki residue of the inverse square of the Dirac operator is proportional to the Einstein-Hilbert action of general relativity. In this paper, we prove a Kastler-Kalau-Walze type theorem for five-dimensional manifolds with boundary. © 2015 World Scientific Publishing Company.

Zhang Z.,Henan Normal University | Xue C.,Northeast Normal University | Liu X.,Northeast Normal University | Zhang Q.,Northeast Normal University | Liu Q.,Northeast Normal University
Tetrahedron | Year: 2011

A facile and efficient approach to a variety of 6-chloro-3,5-disubstituted 3H-pyrimidin-4-ones 2/6 from the readily available cyanoacetamides 1/5 under Vilsmeier conditions was developed, in which the Vilsmeier reagent plays multiple roles and the possible mechanism is discussed. © 2011 Elsevier Ltd. All rights reserved.

Shao X.-Q.,Northeast Normal University | Zheng T.-Y.,Northeast Normal University | Zhang S.,Yanbian University
Journal of the Optical Society of America B: Optical Physics | Year: 2012

A method for synthesizing the Toffoli gate is proposed based solely on the Stark shifts of three superconducting quantum interference devices (SQUIDs). This scheme is robust against the effect of decoherence, since it operates with no excitation of SQUIDs and the coplanar waveguide cavity. The obtained fidelity of the Toffoli gate is high, corresponding to the current typical experimental parameters, and an equivalent physical model for conveniently addressing qubits is also constructed in the coupled-cavity array system. © 2012 Optical Society of America.

Gao T.,Northeast Normal University | Bi H.,Northeast Normal University | Ma S.,Shenyang University | Lu J.,Northeast Normal University
International Journal of Biological Macromolecules | Year: 2010

Aconitum kusnezoffii Reichb. has been used as traditional Chinese medicine over the last 2500 years, but its polysaccharides have been paid little attention by now. In the present study, a hot alkali extracted polysaccharide (AKP) from A. kusnezoffii Reichb. was characterized to be an α-(1 → 3),(1 → 4)-d-glucan with Mw 1.4 × 105 Da, of which (1 → 3)-linked and (1 → 4)-linked α-Glcp residues were in a ratio of 1:7. In vitro antioxidant testing indicated that AKP had significant ferrous ion-chelating ability, reducing power and scavenging effects on DPPH radical, hydroxyl radical, superoxide anion, H2O2 and self-oxidation of 1,2,3-phentriol, suggesting that it should be explored as a novel natural antioxidant. © 2009 Elsevier B.V. All rights reserved.

Li G.,Shenyang University | Wang C.,Northeast Normal University | Zhang X.,Shenyang University
Journal of Coordination Chemistry | Year: 2013

Two supramolecular isomers, {[Cd2(pda)2(1,10'-phen) 2]H2O}n (1) and {[Cd2(pda)2(1,10'- phen)2]4-H2O}n (2) (1,10'-phen = 1,10-phenanthroline, pda = phenylenediacrylate dianion), have been synthesized and characterized by single-crystal X-ray analysis. Complex 1 exhibits a 3D network constructed from 1D rod-shaped secondary building units, while 2 shows a 3D, twofold interpenetrated framework. There exists a reversible transformation between the pair of isomers: when yellow block crystals of 1 are treated under microwave irradiation, colorless plate crystals of 2 are formed; in turn, if crystals of 2 are dissolved in water and left undisturbed about two weeks at room temperature, crystals of 1 reappear. Fluorescence properties of 1 and 2 have also been studied. © 2013 Taylor & Francis.

Feng X.,Northeast Normal University | Zhou W.,Northeast Normal University | Li Y.,Northeast Normal University | Ke H.,CAS Changchun Institute of Applied Chemistry | And 5 more authors.
Inorganic Chemistry | Year: 2012

The reactions of [CuTbL Schiff(H 2O) 3Cl 2]Cl complexes with A- or B-type Anderson polyoxoanions lead to new polyoxometalate-supported 3d-4f heterometallic systems with single-molecule- magnet behavior. © 2012 American Chemical Society.

Liu D.,Huzhou Teachers College | Chen L.,Northeast Normal University | Zhu L.,Changshu Institute of Technology
Journal of Geometry and Physics | Year: 2012

In this paper, Lie superbialgebra structures on the N=. 2 superconformal Neveu-Schwarz algebra are considered by a very simple method. We prove that every Lie superbialgebra structure on the algebra is triangular coboundary. © 2011 Elsevier B.V.

Wu Q.,South China Normal University | Wu Q.,CAS Wuhan Institute of Physics and Mathematics | Wu Q.,Guangdong Medical University | Zhang J.-Q.,CAS Wuhan Institute of Physics and Mathematics | And 3 more authors.
Optics Express | Year: 2015

In contrast to the optomechanically induced transparency (OMIT) defined conventionally, the inverse OMIT behaves as coherent absorption of the input lights in the optomechanical systems. We characterize a feasible inverse OMIT in a multi-channel fashion with a double-sided optomechanical cavity system coupled to a nearby charged nanomechanical resonator via Coulomb interaction, where two counter-propagating probe lights can be absorbed via one of the channels or even via three channels simultaneously with the assistance of a strong pump light. Under realistic conditions, we demonstrate the experimental feasibility of our model by considering two slightly different nanomechanical resonators and the possibility of detecting the energy dissipation of the system. In particular, we find that our model turns to be a unilateral inverse OMIT once the two probe lights are different with a relative phase, and in this case the relative phase can be detected precisely. © 2015 Optical Society of America.

Liang D.,Northeast Normal University | Wang M.,Northeast Normal University | Wang M.,Dalian University of Technology | Bekturhun B.,Northeast Normal University | And 2 more authors.
Advanced Synthesis and Catalysis | Year: 2010

The synthesis of polyfunctionalized 4Hchromenes 3 and dihydrocoumarins 4 has been developed from the same substrates. Catalyzed by copper(II) bromide (0.3 equiv.), the reactions of the easily available ketene dithioacetals 1 with 2-(hydroxymethyl)phenols 2 lead to 4/7-chromenes 3 in high to excellent yields in dichloromethane solvent, whereas, 3,4-trans-disubstituted dihydrocoumarins 4 are obtained in high yields with high diastereoselectivities by prolonging the reaction time or changing the solvent from dichloromethane to acetonitrile. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liu Y.,Northeast Normal University | Wang M.,Northeast Normal University | Wang M.,Dalian University of Technology | Yuan H.,Northeast Normal University | Liu Q.,Northeast Normal University
Advanced Synthesis and Catalysis | Year: 2010

A new application of copper(II) bromideactivated ketene dithioacetals as nucleophiles in organic chemistry has been developed. Under the cocatalysis of copper(II) bromide (2.0 mol%) and boron trifluoride etherate (10 mol%), the conjugate addition and sequential cyclization of a-electron-withdrawing group-substituted ketene dithioacetals with p-quinones in acetonitrile at room temperature gave a variety of benzofurans. This formal [3 + 2] cycloaddition provides a general method for catalytic synthesis of polyfunctionalized benzofurans with the ad-vantages of readily available starting materials, cheap catalysts, mild reaction conditions, good yields and wide range of synthetic potential for the benzofuran products. Further transformations of the resulting benzofurans to 2-aminobenzofurans and benzofuro[2,3-d]pyrimidine derivatives are also investigated. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

Liu Y.,Northeast Normal University | Liu J.,Northeast Normal University | Wang M.,Northeast Normal University | Wang M.,Dalian University of Technology | Liu Q.,Northeast Normal University
Advanced Synthesis and Catalysis | Year: 2012

A highly regioselective allylic substitution of quinone monoketals with a-oxoketene dithioacetals is achieved under the catalysis of only tin tetrachloride (1 mol%). The advantages of the reaction, including its simplicity, rapidity, low catalyst loading of inexpensive tin tetrachloride, mild conditions and; in particular, the regiospecificity, is proposed to be due to a pseudo-intramolecular process. This new synthetic method provides a facile [3+2] cycloaddition route to benzofurans and is highlighted by the synthesis of coumestans. © 2012 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim.

Ma L.,Northeast Normal University | Su F.,Northeast Normal University | Guo W.,Northeast Normal University | Zhang S.,Northeast Normal University | And 2 more authors.
Microporous and Mesoporous Materials | Year: 2013

Mesoporous propylthiol group-functionalized silica supported manganese(III)-salen complexes with 2D hexagonal p6mm and 3D interconnected sponge-like structures were prepared by a multistep grafting method by using tetraethyl orthosilicate (TEOS) or 1,2-bis(trimethoxysilyl)ethane (BTMSE) as a silica source and 3-mercaptopropyltriethoxysilane (MPTES) as a linker reagent. The structure, morphology, and porosity of the resulting hybrid materials were well-characterized by spectroscopy method, X-ray diffraction analysis, transmission electron microscopy, and nitrogen physisorption measurement. Subsequently, their oxidation catalytic activity and stability were evaluated through the epoxidation of styrene by using aqueous NaClO as the oxygen source, and the influences of sulfur atom in the hybrid materials, textural properties and pore morphologies of the materials, and the kinds of the substituents in the diimine bridges of the manganese(III)-salen complexes on the catalytic activity of the hybrid materials were discussed. © 2012 Elsevier Inc. All rights reserved.

Wang X.,Beijing University of Chemical Technology | Chen W.,Beijing University of Chemical Technology | Song Y.-F.,Beijing University of Chemical Technology | Song Y.-F.,Northeast Normal University
European Journal of Inorganic Chemistry | Year: 2014

The directional self-assembly of exfoliated layered europium hydroxide (LEuH) nanosheets and europium-containing heteropolytungstate anions has been achieved by mixing an LEuH colloidal solution and a Na9EuW 10O36·32H2O (EuW10) solution at room temperature leading to the formation of a new inorganic/inorganic hybrid material, Eu2(OH)5(EuW10O36) 0.11·5.5H2O (LEuH-EuW10). The use of LEuH-EuW10 in extractive catalytic oxidative desulfurization (ECODS) showed that highly efficient and selective deep desulfurization can be achieved in only 15 min under mild conditions. A maximum turnover number (TON) of around 1600 has been achieved. In addition, the catalyst can be recycled and reused at least 10 times with only a slight loss of catalytic efficiency. The self-assembly of exfoliated layered europium hydroxides (LEuH) and Na 9EuW10O36·32H2O (EuW 10) led to a new inorganic/inorganic hybrid material, LEuH-Euw 10. The use of LEuH-EuW10 in extractive catalytic oxidative desulfurization showed that this catalyst is highly efficient and selective for the deep desulfurization of dibenzothiophene in the presence of H2O2 and [omim]PF6 under mild conditions. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Jiang C.,Huaiyin Normal University | Liu H.,Huaiyin Normal University | Liu H.,Northeast Normal University | Cui Y.,Huaiyin Normal University | And 3 more authors.
Optics Express | Year: 2013

We theoretically demonstrate the mechanically mediated elec-tromagnetically induced transparency in a two-mode cavity optomechanical system, where two cavity modes are coupled to a common mechanical resonator. When the two cavity modes are driven on their respective red sidebands by two pump beams, a transparency window appears in the probe transmission spectrum due to destructive interference. Under this situation the transmitted probe beam can be delayed as much as 4 μs, which can be easily controlled by the power of the pump beams. © 2013 Optical Society of America.

Su C.,Changchun University of Technology | Su C.,Northeast Normal University | Shao C.,Northeast Normal University | Liu Y.,Northeast Normal University
Journal of Colloid and Interface Science | Year: 2011

Herein, we have demonstrated that the electrospun nanofibers of TiO2/CdS heteroarchitectures could be fabricated through combining electrospinning technique with hydrothermal process. The configuration, crystal structure, and element composition of the as-prepared TiO2/CdS heteroarchitectures were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), resonant Raman spectrometer, X-ray photoelectron spectroscopy (XPS). The results indicated that the high-density hexagonal wurtzite CdS crystalline particles of ca. 6-40nm in diameter were uniformly and closely grown on anatase TiO2 nanofibers. Especially, the light-absorption properties as well as photocatalytic characteristics of pure TiO2 nanofibers and TiO2/CdS heteroarchitectures with different amount loading of CdS were also investigated. The absorption of TiO2/CdS heteroarchitectures was extended to the visible due to effective immobilization of sensitizing agent CdS on TiO2. In contrast with the pure TiO2 nanofibers, the TiO2/CdS heteroarchitectures showed excellent photocatalytic activity by using rhodamine B dye as a model organic substrate under visible-light irradiation. It was worth noting that the cooperative photocatalytic mechanism of the TiO2/CdS heteroarchitectures was also discussed. © 2011 Elsevier Inc.

Liu B.,Northeast Normal University | Zheng G.,Northeast Normal University | Liu X.,Northeast Normal University | Xu C.,Northeast Normal University | And 3 more authors.
Chemical Communications | Year: 2013

Palladium-catalyzed cyclization of β-alkylthio dienone derivatives affords 2-cyclopentenones in a regio- and stereoselective manner in the presence of silane. C-S activation, intramolecular carbopalladation and hydrogenolysis construct the cascade process. © 2013 The Royal Society of Chemistry.

Liu B.,Northeast Normal University | Liu B.,Jilin Normal University | Yang J.,Northeast Normal University | Yang G.-C.,Changchun University of Technology | Ma J.-F.,Northeast Normal University
Inorganic Chemistry | Year: 2013

Four novel polyoxometalate-based copper(I)-organic frameworks, namely, [CuI 2(cis-L1)2][CuI 2(trans-L1)2Mo6O18(O 3AsPh)2] (1), [CuI 4(L2) 4Mo6O18(O3AsPh)2] (2), [CuI 4(L3)4Mo6O18(O 3AsPh)2] (3), and [CuI 4(L4) 2Mo6O18(O3AsPh)2] (4) (L1 = 1,3-bis(1,2,4-triazol-1-yl)propane, L2 = 1,4-bis(1,2,4-triazol-1-yl)butane, L3 = 1,5-bis(1,2,4-triazol-1-yl)pentane, and L4 = 1,6-bis(1,2,4-triazol-1-yl) hexane), have been successfully synthesized under hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, infrared spectra (IR), UV-vis spectra, powder X-ray diffraction (PXRD), and thermogravimetric (TG) analyses. Compound 1 is composed of two crystallographically independent and distinct polymeric motifs: one-dimensional (1D) S-shaped chain and two-dimensional (2D) undulated layer. The S-shaped chains penetrated into the 2D parallel layers to generate an unusual 1D + 2D → three-dimensional (3D) polypseudo-rotaxane framework. In 2, the As2Mo6 polyoxoanions in tetradentate modes link four neighboring -L2-Cu-L2- chains to produce a rare 3D trinodal (3,4)-connected self-penetrated framework with Point Symbol of (8 3)2(82·124). In 3, adjacent CuI atoms are linked by As2Mo6 polyoxoanions and L3 ligands into a 2D layer. The layers are further interlocked by the two nearest neighboring ones to form a 3D polycatenated framework. In 4, L4 ligands bridge four CuI atoms to yield 2D wavelike layers, which are further linked by the octadentate As2Mo6 polyoxoanions to form a 3D tetranodal (3,4,6)-connected framework with Point Symbol of (6 3)(4·63·82)(64· 82)(42·62·810· 10). In addition, the photocatalytic activities of compounds 1, 3, and 4 for decomposition of methylene blue (MB) under UV light have been investigated. Moreover, their electrochemical properties have also been studied in 1 M H 2SO4 aqueous solution. © 2012 American Chemical Society.

Su C.,Northeast Normal University | Su C.,Changchun University of Technology | Shao C.,Northeast Normal University | Liu Y.,Northeast Normal University
Journal of Colloid and Interface Science | Year: 2010

In this paper, we have successfully fabricated TiO2/PbS heteroarchitectures with high-quality single-crystalline PbS nanostructures well-erected on electrospun TiO2 nanofibers matrices via hydro(solvo)thermal method using l-cysteine as the sulfur donor and chelating reagent. The experiment results showed that the morphology and size of secondary PbS nanostructures grown on TiO2 nanofibers can be changed significantly by utilizing two kinds of different reaction solvents (water and acetylacetone, respectively). In case of water serving as solvent, the superb cube-shaped PbS nanocrystals with the edge length ranging from 150 to 300nm were prepared. While acetylacetone acting as solvent, the high-density PbS nanoparticles with 10-30nm in length were obtained. And, it is interesting that PbS nanostructures were not only uniformly monodispersed but also closely attached to TiO2 nanofibers surface. What is more, the further studies suggested that the formation of TiO2/PbS heteroarchitectures might take on chelation-anchoring-nucleation-directional growth strategy. © 2010 Elsevier Inc.

Liu Z.,Northeast Normal University | Liao P.,Northeast Normal University | Bi X.,Northeast Normal University | Bi X.,Dalian University of Technology
Chemistry - A European Journal | Year: 2014

Reductive deoxyallenylation of sterically hindered tertiary propargylic alcohols was realized on reaction with 2-nitrobenzenesulfonylhydrazide (NBSH) by the combined use of Lewis and Brønsted acid catalysts. This method features a broad substrate scope, mild reaction conditions, and good functional-group tolerance, and affords various mono-, di-, and trisubstituted allenes in good-to-excellent yields. The synthetic utility of this method was demonstrated by the synthesis of 2H-chro-menes and 1,2-dihydroquinolines. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ma L.,Northeast Normal University | Su F.,Northeast Normal University | Zhang X.,Northeast Normal University | Song D.,Northeast Normal University | And 2 more authors.
Microporous and Mesoporous Materials | Year: 2014

A series of manganese-salen-based hybrid catalysts, Mn(salen)/C 3N2-Schiff-SBA-15 and Mn(salen)/C4N 2-Schiff-SBA-15, were demonstrated for the first time by a multistep grafting method. As-prepared hybrid catalysts exhibited well-defined mesostructure including highly ordered 2D hexagonal p6mm pore geometry, large BET surface area (268-293 m2 g-1), uniform pore size (5.2-6.4 nm) as well as high pore volume (0.35-0.41 cm3 g -1); meanwhile, the structure of the starting manganese-salen complexes and other functionalities (Schiff ligand and C3N 2 or C4N2 unit) remained intact in the hybrid catalysts. These hybrid catalysts were subsequently utilized as efficient, selective and reusable catalysts in epoxidation of alkenes including styrene, cyclohexene and 1-phenylcyclohexene by using NaOCl as the oxidant, and the contribution of imidazole or piperazine and Schiff base to the overall catalytic activity of the hybrid catalysts were evaluated and explained. © 2013 Elsevier Inc. All rights reserved.

Zhao Y.-L.,CAS Changchun Institute of Applied Chemistry | Zhao Y.-L.,Northeast Normal University | Wu G.-J.,Northeast Normal University | Li Y.,CAS Changchun Institute of Applied Chemistry | And 3 more authors.
Chemistry - A European Journal | Year: 2012

We present a general approach to C-P bond formation through the cross-coupling of aryl halides with a dialkyl phosphite, diphenylphosphine oxide, and diphenylphosphane by using [NiCl 2(dppp)] as catalyst (dppp=1,3-bis(diphenylphosphino)propane). This catalyst system displays a broad applicability that is capable of catalyzing the cross-coupling of aryl bromides, particularly a range of unreactive aryl chlorides, with various types of phosphorus substrates, such as a dialkyl phosphite, diphenylphosphine oxide, and diphenylphosphane. Consequently, the synthesis of valuable phosphonates, phosphine oxides, and phosphanes can be achieved with one catalyst system. Moreover, the reaction proceeds not only at a much lower temperature (100-120 °C) relative to the classic Arbuzov reaction (ca. 160-220 °C), but also without the need of external reductants and supporting ligands. In addition, owing to the relatively mild reaction conditions, a range of labile groups, such as ether, ester, ketone, and cyano groups, are tolerated. Finally, a brief mechanistic study revealed that by using [NiCl 2(dppp)] as a catalyst, the Ni II center could be readily reduced in situ to Ni 0 by the phosphorus substrates due to the influence of the dppp ligand, thereby facilitating the oxidative addition of aryl halides to a Ni 0 center. This step is the key to bringing the reaction into the catalytic cycle. Making bonds: C-P bonds were formed by the Ni-catalyzed cross-coupling of aryl halides and phosphorus substrates without the need of external reductants. Aryl bromides and less reactive aryl chlorides underwent smooth coupling with several different phosphorus substrates to afford phosphonates, phosphine oxides, and phosphines (see scheme; dppp=1,3-bis(diphenylphosphino)propane). Due to the mild reaction conditions, a range of labile groups, such as ether, ester, ketone, and cyano groups, are tolerated. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhang X.Y.,Dalian University of Technology | Huang X.L.,Liaoning Normal University | Yi X.X.,Northeast Normal University
Journal of Physics A: Mathematical and Theoretical | Year: 2014

The effects of a non-Markovian reservoir on the performance of an ideal quantum Otto heat engine are investigated. By coupling the cavity to a hot non-Markovian reservoir, the cavity can be enabled to reach a steady state corresponding to an effective temperature higher than the temperature of the hot reservoir. This observation shows that the quantum Otto heat engine can transport heat from a cold reservoir to a hot reservoir with positive net work output under certain conditions. Also, when the temperature of the hot reservoir lies in certain regions, the efficiency of the quantum Otto heat engine can exceed the efficiency of classical Carnot heat engine. © 2014 IOP Publishing Ltd.

Zhang L.,Northeast Normal University | Liu Z.,Northeast Normal University | Li H.,Northeast Normal University | Fang G.,Northeast Normal University | And 5 more authors.
Organic Letters | Year: 2011

A novel copper-mediated chelation-assisted ortho C-H nitration of (hetero)arenes has been developed for the first time, which used dioxygen as terminal oxidant and 1, 2, 3-TCP as solvent, leading to the synthesis of nitroaromatics with excellent regioselectivity and in good yields. Mechanistic investigations indicate a mechanism involving a four-centered transition state, with simultaneous cleavage of an ortho C-H bond and a N-O bond of the nitrate anion on the 2-arylpyridine-coordinated copper(II) complex. © 2011 American Chemical Society.

Guan J.,CAS Changchun Institute of Applied Chemistry | Guan J.,University of Chinese Academy of Sciences | Wu G.-J.,Northeast Normal University | Han F.-S.,CAS Changchun Institute of Applied Chemistry | Han F.-S.,Dalian University of Technology
Chemistry - A European Journal | Year: 2014

A novel protocol for the Pd-catalyzed ortho-arylation of aryl phosphinamide with boronic acid is reported. By using phosphinamide as a new directing group, the reaction proceeds efficiently under mild conditions at 40 °C. Mechanistic studies reveal that the reaction proceeds via a PdII to Pd0 cycle. The phosphinamide group is also shown to be an effective orienting group for direct C-H amination. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhou Y.H.,Dalian University of Technology | Shen H.Z.,Dalian University of Technology | Yi X.X.,Northeast Normal University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

The photon blockade based on weak nonlinearities is called the unconventional photon blockade. The study of the unconventional photon blockade in recent decades has mainly focused on the χ(3) Kerr nonlinearity. In this paper, we study the photon blockade in two weakly coupled nonlinear cavities via χ(2) nonlinearity, where χ(2) mediates the conversion of a single photon in the cavity with high frequency into two photons with low frequency in another cavity. When the two cavity modes are driven simultaneously, our calculations show that the strong photon antibunching can be obtained in the cavity. The optimal condition for strong antibunching is found by analytic calculations and numerical simulations, and discussions of the optimal condition are presented. The differences between the present scheme and that with χ(3) nonlinearity are discussed. This scheme is not sensitive to the change of decay rates, which makes the experimental realization easy. © 2015 American Physical Society.

Shi Z.C.,Dalian University of Technology | Zhao X.L.,Dalian University of Technology | Yi X.X.,Northeast Normal University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

Based on the Lyapunov control, we present a scheme to realize state transfer with high fidelity by only modulating the boundary spins in a quantum spin-1/2 chain. Recall that the conventional transmission protocols aim at nonstationary state (or information) transfer from the first spin to the end spin at a fixed time. The present scheme possesses the following advantages. First, the scheme does not require precise manipulations of the control time. Second, it is robust against uncertainties in the initial states and fluctuations in the control fields. Third, the controls are exerted only on the boundary sites of the chain. It works for variable spin-1/2 chains with different periodic structures and has good scalability. The feasibility to replace the control fields by square pules is explored, which simplifies the realization in experiments. © 2015 American Physical Society.

Hou S.C.,Northeast Normal University | Hou S.C.,Dalian University of Technology | Liang S.L.,Northeast Normal University | Yi X.X.,Northeast Normal University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

Although a number of measures for quantum non-Markovianity have been proposed recently, it is still an open question whether these measures directly characterize the memory effect of the environment, i.e., the dependence of a quantum state on its past in a time evolution. In this paper, we present a criterion and propose a measure for non-Markovianity with clear physical interpretations of the memory effect. The non-Markovianity is defined by the inequality T(t2,t0)≠T(t2,t1)T(t1,t0) in terms of memoryless dynamical map T introduced in this paper. This definition is conceptually distinct from that based on divisibility used by Rivas et al. [Phys. Rev. Lett. 105, 050403 (2010)PRLTAO0031-900710.1103/PhysRevLett.105.050403], whose violation is manifested by noncomplete positivity of the dynamical map. We demonstrate via a typical quantum process that without Markovian approximation, nonzero memory effects (non-Markovianity) always exist even if the non-Markovianity is zero by the other non-Markovianity measures. © 2015 American Physical Society.

Shen H.Z.,Northeast Normal University | Shen H.Z.,Dalian University of Technology | Zhou Y.H.,Northeast Normal University | Zhou Y.H.,Dalian University of Technology | Yi X.X.,Northeast Normal University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

In this paper, we show that photon blockade can be observed in a system with weak Kerr nonlinearities. The system consists of two spatially overlapping single-mode semiconductor cavities with tunable one- and two-photon tunneling. We find that both conventional and unconventional single-photon blockades are controllable by manipulating the phase in the hopping regardless of the weakness of nonlinearity. We refer to the photon blockade with weak nonlinearities as an unconventional photon blockade. The unconventional photon blockade effect originates from the destructive interference between different paths from the ground state to two-photon states. We analytically derive the exact optimal conditions for strong antibunching, which are in good agreement with those obtained by numerical simulations. The optimal parameters for photon blockade are derived. Based on these parameters, the semiconductor cavity systems can be used as a single-photon source in regimes of both weak and strong nonlinearities. © 2015 American Physical Society.

Cao F.,Northeast Normal University | Guo S.,Northeast Normal University | Ma H.,Northeast Normal University | Yang G.,Changchun University of Technology | And 2 more authors.
Talanta | Year: 2011

An improved nonenzymatic glucose sensor based on copper oxide-doped nickel oxide composite microfibers (CuO-NiO-MFs) modified fluorine tin oxide (FTO) electrode was prepared by electrospinning and calcination technologies without using any immobilization. The results of cyclic voltammetry (CV) and chronoamperometry demonstrated that the CuO-NiO-MFs modified electrode displayed much higher electrocatalytic activity than the nickel oxide microfibers (NiO-MFs) modified electrode toward glucose. The nonenzymatic glucose sensor based on CuO-NiO-MFs showed the highest sensitivity of 3165.53 μA mM -1 cm -2 with the lowest detection limit of 1 × 10 -9 M (signal/noise ratio (S/N) = 3) in the nonenzymatic glucose sensors that have been reported in the literature. Additionally, its application for detecting glucose concentration of human serum sample showed good agreement with the results obtained from automatic biochemical analyzer. © 2011 Elsevier B.V. All rights reserved.

Hu Y.,Northeast Normal University | Fu X.,Northeast Normal University | Barry B.-D.,Northeast Normal University | Bi X.,Northeast Normal University | And 3 more authors.
Chemical Communications | Year: 2012

The regiospecific β-lactam ring-opening/recyclization reaction of N-aryl-3-spirocyclic-β-lactams, made by the one-pot cyclization reaction of acetoacetanilides, has been achieved for the first time using a Lewis-Brønsted acids combined superacid catalyst system, thus providing an efficient entry to 3-spirocyclicquinolin-4(1H)-ones. A mechanism involving superacid-catalysis was proposed. © 2012 The Royal Society of Chemistry.

Su C.,Changchun University of Technology | Liu L.,Changchun Institute of Technology | Zhang M.,Northeast Normal University | Zhang Y.,Changchun University of Technology | Shao C.,Northeast Normal University
CrystEngComm | Year: 2012

In this work, Ag/TiO 2 nanoheterostructures with Ag nanocrystals well-grown on TiO 2-based nanofiber mats have been achieved by means of a novel and straighforward protocol combining an electrospinning technique and a solvothermal process. The experimental results indicated that the morphology and size of the secondary Ag nanostructures could be tailored by altering the experimental parameters, such as the reaction time and solvent as well as the reducing agent in the solvothermal treatment. The investigation of photocatalytic ability showed that the Ag/TiO 2 nanoheterostructures possess an excellent photocatalytic activity superior to the pure TiO 2 nanofiber for the degradation of Rhodamine B (RB) dye driven by visible light. The results indicated that Ag might be responsible for the visible light induced photocatalytic degradation by improving the photogenerated electrons and holes separation as well as charge migration, allowing both the electrons and holes to partake in the overall photocatalytic reaction. In addition, Ag has a good light absorption capability, extending the response of TiO 2 to visible light. Finally, the corresponding possible mechanism related to the photocatalytic performance of the Ag/TiO 2 nanoheterostructures was discussed in detail. Additionally, the separation and recovery process of the Ag/TiO 2 nanoheterostructures might be easily acheived by sedimentation without a decrease in the photocatalytic ability because of their particular one-dimensional nanostructured nature. © 2012 The Royal Society of Chemistry.

He Y.-C.,Northeast Normal University | Yang J.,Northeast Normal University | Yang G.-C.,Changchun University of Technology | Kan W.-Q.,Northeast Normal University | Ma J.-F.,Northeast Normal University
Chemical Communications | Year: 2012

We describe an exceedingly rare example of solid-state single-crystal-to- single-crystal transformation from a 2D layer to a known 3D framework via lattice iodine release, which involves the formation of a new Cu-O ligand bond and a change in the metal coordination geometry. This journal is © 2012 The Royal Society of Chemistry.

Shen H.Z.,Dalian University of Technology | Zhou Y.H.,Dalian University of Technology | Yi X.X.,Northeast Normal University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

The semiconductor diode, which acts as an electrical rectifier and allows unidirectional electronic transports, is the key to information processing in integrated circuits. Analogously, an optical rectifier (or diode) working at specific target wavelengths has recently become a highly sought-after device in optical communication and signal processing. In this paper, we propose a scheme to realize an optical diode for photonic transport at the level of few photons. The system consists of two spatially overlapping single-mode semiconductor microcavities coupled via χ(2) nonlinearities. The photon blockade is predicted to take place in this system. These photon blockade effects can be achieved by tuning the frequency of the input laser field (driving field). Based on those blockades, we analytically derive the one- and two-photon current in terms of a zero and a finite time-delayed two-order correlation function. The results suggest that the system can serve as a one- and two-photon quantum optical diode which allows transmission of photons in one direction much more efficiently than in the other. © 2014 American Physical Society.

Su C.,Changchun University of Technology | Tong Y.,Changchun University of Technology | Zhang M.,Northeast Normal University | Zhang Y.,Changchun University of Technology | Shao C.,Northeast Normal University
RSC Advances | Year: 2013

TiO2/polyacrylonitrile (TiO2/PAN) hybrid nanofibers with small TiO2 nanoparticles well-immobilized on the electrospun PAN nanofibers have been successfully fabricated by means of a combination of an electrospinning technique and a hydrothermal process. The as-fabricated hybrid nanofibers were characterized by field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, and Brunauer-Emmett-Teller analysis. The results revealed that the TiO2/PAN hybrid nanofibers possessed a large surface area as well as being flexible in nature. Such hybrid nanofibers materials have exhibited outstanding performance for the photocatalytic degradation of phenol under UV light irradation. And, by adjusting the operating parameters during the photocatalytic process, the results further showed that the photoreactor pattern, initial pH value and concentration of phenol solution had important influence on phenol degradation. What's more, repeating the experiments five times indicated that the catalyst is stable and recyclable. © The Royal Society of Chemistry 2013.

Couillet R.,Supelec | Silverstein J.W.,North Carolina State University | Bai Z.,Northeast Normal University | Debbah M.,Supelec
IEEE Transactions on Information Theory | Year: 2011

In this paper, a new method is introduced to blindly estimate the transmit power of multiple signal sources in multiantenna fading channels, when the number of sensing devices and the number of available samples are sufficiently large compared to the number of sources. Recent advances in the field of large dimensional random matrix theory are used that result in a simple and computationally efficient consistent estimator of the power of each source. A criterion to determine the minimum number of sensors and the minimum number of samples required to achieve source separation is then introduced. Simulations are performed that corroborate the theoretical claims and show that the proposed power estimator largely outperforms alternative power inference techniques. © 2011 IEEE.

Wong A.W.-K.,City University of Hong Kong | Wu Y.,Northeast Normal University | Chen H.-C.,Chinese University of Hong Kong
Neuroscience | Year: 2014

This study investigates the role of phonology in reading logographic Chinese. Specifically, whether phonological information is obligatorily activated in reading Chinese two-character compounds was examined using the masked-priming paradigm with event-related potential (ERP) recordings. Twenty-two native Cantonese Chinese speakers participated in a lexical decision experiment. The targets were visually presented Chinese two-character strings and the participants were asked to judge whether the target in each trial was a legitimate compound word in Chinese. Each target was preceded by a briefly presented word prime. The prime and target shared an identical constituent character in the Character-related condition, a syllable in the Syllable-related condition, were semantically related in the Semantic-related condition, and were unrelated (both phonologically and semantically) in the control condition. The prime-target relationship was manipulated to probe the effects of word-form (i.e., character- or syllable-relatedness) and word-semantic relatedness on phonological (as indexed by an N250 ERP component) and semantic (as indexed by an N400 ERP component) processing. Significant and comparable facilitation effects in reaction time, relative to the control, were observed in the Character-related and the Semantic-related conditions. Furthermore, a significant reduction in ERP amplitudes (N250), relative to the control, was obtained in the Character-related condition in the time window of 150-250. ms post target. In addition, attenuation in ERP amplitudes was found in the Semantic-related condition in the window of 250-500. ms (N400). However, no significant results (neither behavioral nor ERP) were found in the Syllable-related condition. These results suggest that phonological activation is not mandatory and the role of phonology is minimal at best in reading Chinese two-character compounds. © 2013 IBRO.

Guo Z.,Hebei University of Engineering | Mu J.,Hebei University of Engineering | Chen B.,Northeast Normal University
Ceramics International | Year: 2015

The three-dimensional flower-like TNFePc hierarchical microstructures were fabricated by a simple solvothermal method. The as-obtained products exhibited high adsorption capacity and excellent simultaneously visible-light-driven photocatalytic performance for Rhodamine B (RB) under visible-light. Repetitive tests showed that the flower-like TNFePc hierarchical microstructures could maintain high catalytic activity over several cycles, and it had a better regeneration capability under mild conditions. Finally, a possible mechanism for the formation of three-dimensional flower-like TNFePc was suggested based on the evolution of morphology as a function of solvothermal time, which involved the initial formation of microparticles followed by their recrystallize to microspheres and transformation into three-dimensional flower-like hierarchical microstructures by mass diffusion and Ostwald ripening.

Yu L.,Northeast Normal University | Yu L.,University of Leeds | Zhou Y.,Northeast Normal University | Knox J.P.,University of Leeds
Planta | Year: 2011

A range of molecular probes for cell wall polysaccharides has been used to explore the structure and location of water-extracted pectic polysaccharides occurring in fractions isolated from ginseng roots. The LM19 homogalacturonan (HG) epitope was abundant in an HG fraction and analysis of LM19 binding to a rhamnogalacturonan-I (RG-I) rich-fraction indicated that the LM19 epitope is sensitive to acetylation. A specific RG-I epitope (LM16), four arabinogalactan-protein (AGP) epitopes (LM2, LM14, JIM16, MAC207) and an extensin epitope (JIM20) were found to be abundant and co-located in several isolated polysaccharide fractions including an arabinogalactan fraction and two RG-I fractions. Detection of the RG-I, AGP and extensin epitopes identified in isolated polysaccharide fractions in sections of ginseng roots indicated that they were most abundant in secretory cavities found in the cortical regions of ginseng roots. In addition, the immunocytochemical study indicated that polysaccharide epitope masking is a widespread phenomenon in the primary cell walls of ginseng roots. © 2011 Springer-Verlag.

Liu X.,Northeast Normal University | Liu Y.,Northeast Normal University | Yan D.,Northeast Normal University | Zhu H.,Northeast Normal University | And 3 more authors.
Journal of Materials Chemistry | Year: 2012

A novel white-light-emitting phosphor, 12CaO·7Al 2O 3:Ce 3+, Dy 3+with H - encaging, was prepared by the solid-state reaction in H 2 atmosphere. Upon excitation at 362 nm, the phosphor shows intense white-light emission that combines the blue and yellow emissions at 476 and 576 nm, assigned to the 4F 9/2 → 6H 15/2 and 4F 9/2 → 6H 13/2 transitions of Dy 3+, respectively. A weak broad blue emission centered at 430 nm is also observed and attributed to the 5d-4f transitions of Ce 3+. The photoluminescence intensity of Dy 3+ increases greatly with increasing Ce 3+ concentration, indicating that the effective energy transfer occurred from Ce 3+ to Dy 3+ in the phosphor. In particular, the phosphor can be converted to a persistent semiconductor upon ultraviolet irradiation due to the electrons released from the encaged H - ions, and the electrical conductivity is measured to be 10 -2 S cm -1. The conductive phosphor exhibits excellent white-light emission (CIE coordinate of (0.324, 0.323)) under low-voltage (5 kV) electron beam excitation, suggesting that the phosphor is a potential candidate for applications in field emission displays. © The Royal Society of Chemistry 2012.

Xu C.,China Earthquake Administration | Xu X.,China Earthquake Administration | Yao Q.,China Earthquake Networks Center | Wang Y.,Northeast Normal University
Quarterly Journal of Engineering Geology and Hydrogeology | Year: 2013

The main purpose of this research is to evaluate the modelling capability and predictive power of a bivariate statistical method for earthquake-triggered landslide susceptibility mapping. A weight index (Wi) model was developed for the 2008 Wenchuan earthquake region in Sichuan Province, China, using a wide range of optical remote sensing data, and carried out on the basis of a geographic information system (GIS) platform. The 2008 Wenchuan earthquake triggered 196007 landslides, with a total area of 1150.43 km2, in an approximately oblong area around the Yingxiu-Beichuan coseismic surface fault-rupture (the Yingxiu-Beichuan fault). The landslides of the study area were mapped using visual interpretation of high-resolution satellite images and aerial photographs, both pre- and post-earth-quake, and checked in the field at various locations. As a consequence, a nearly complete inventory of landslides triggered by the Wenchuan earthquake was constructed. Topographic and geological data and earthquake-related information were collected, processed and constructed into a spatial database using GIS and image processing technologies. A total of 10 controlling parameters associated with the earthquake-triggered landslides were selected, including elevation, slope angle, slope aspect, slope curvature, slope position, lithology, seismic intensity, peak ground acceleration (PGA), distance from the Yingxiu-Beichuan fault, and distance along this fault. To assist with the development of the model, the complete dataset of 196007 landslides was randomly partitioned into two subsets; a training data-set, which contains 70% of the data (137204 landslides, with a total area of 809.96 km2), and a testing dataset accounting for 30% of the data (58803 landslides, with a total area of 340.47 km2). A landslide susceptibility index map was generated using the training dataset, the 10 impact factors, and the Wi model. In addition, for a conditionally dependent factor analysis, seven other factor-combination cases were also used to construct landslide susceptibility index maps. Finally, these eight landslide suscep-tibility maps were compared with the training data and testing data to obtain model capability (success rate) and predictive power (predictive rate) information. The validation results show that the success and predictive rates of the Wi modelling exceeded 90% for the approaches that include the use of seismic factors. The final landslide susceptibility map can be used to identify and delineate unstable suscepti-bility-prone areas, and help planners to choose favourable locations for development schemes, such as infrastructure, construction and environmental protection schemes. The generic component of this research would allow application in other regions affected by high-intensity earthquakes and unstable terrain covering very large areas. © 2013 The Geological Society of London.

Dai P.,Northeast Normal University | Zhang X.,Northeast Normal University | Bian L.,Northeast Normal University | Lu S.,Northeast Normal University | And 2 more authors.
Journal of Materials Chemistry C | Year: 2013

Two series of K1-xNaxSrPO4:0.005Eu 2+ and K0.4Na0.6Sr0.995-yPO 4:0.005Eu2+, yTb3+ phosphors are synthesized via a high-temperature solid-state reaction. Their emission color can be tuned from deep blue to blue-green by modulating the crystal field strength and energy transfer. Partial substitution of K+ with Na+ results in a contraction and distortion of the unit cell of the K1-xNa xSr0.995PO4:0.005Eu2+ host, tuning the emission from 426 to 498 nm. The red-shifted emission is attributed to an increased crystal field splitting for Eu2+ in a lowered symmetry crystal field. The tunable emission is further demonstrated in the cathodoluminescence spectra, which indicates that the luminescence distribution of the K1-xNaxSr0.995PO4:0. 005Eu2+ phosphor is very homogenous. Additionally, utilizing the principle of energy transfer, the emission color can be further tuned by co-doping with Tb3+. The chromaticity coordinates for the co-doped phosphor, K0.4Na0.6Sr0.995-yPO 4:0.005Eu2+, yTb3+, can be adjusted from (0.202, 0.406) for y = 0 to (0.232, 0.420) for y = 0.09. The energy transfer processes from the sensitizer (Eu2+) to the activator (Tb 3+) are studied and demonstrated to have a resonance-type dipole-dipole interaction mechanism, with the critical distance of the energy transfer calculated to be 12.46 Å using a concentration quenching method. This journal is © The Royal Society of Chemistry 2013.

Cheng C.-L.,CAS Dalian Institute of Chemical Physics | Cheng C.-L.,Northeast Normal University | Zhao G.-J.,CAS Dalian Institute of Chemical Physics
Nanoscale | Year: 2012

In the present work, we explored the diameter selectivity of dynamic self-assembly for the single-strand DNA (ssDNA) encapsulation in double-walled nanotubes (DWNTs) via molecular dynamics simulation method. Moreover, the pulling out process was carried out by steered molecular dynamics simulations. Considering π-π stacking and solvent accessibility together, base-CNT binding should be strongest on a graphene sheet and weakest on the inner CNT surface. When pulling the ssDNA out of the single-walled carbon nanotube (SWNT), the force exhibits characteristic fluctuations around a plateau about 300 pN. Each fluctuation force pulse to pull ssDNA corresponds to the exit of one base. In addition, the solvents used for the system are also of significant interest. Water does play an important role in encapsulation process but doesn't in the pulling out process. © 2012 The Royal Society of Chemistry.

Ding Y.,Northeast Normal University | Ding Y.,Jilin Business and Technology College | Meng J.-X.,Northeast Normal University | Chen W.-L.,Northeast Normal University | Wang E.-B.,Northeast Normal University
CrystEngComm | Year: 2011

Four new supramolecular compounds, namely, [HMnII(bix) 4][PMoVI 8VV 4O 40(VIVO)2]·2H2O (1), [Zn(bix)4][PMoVI 9VV 3O40(VIVO)2]·2H2O (2), [Cu(bix)4][PMoVI 9VV 3O40(VIVO)2]·4H2O (3) and [CuI(bix)]2[CuI(bix)](bix)[PMo 12O40]·4H2O (4) (bix = 1,4-Bis(imidazol-1-ylmethyl)benzene), have been synthesized under hydrothermal conditions, which are constructed from Keggin/pseudo-Keggin polyoxometalate (POM) secondary building units (SBUs) and transition metal complexes. Compound 1 consists of an infinite 1D chain constructed from [HMnII(bix) 4]3+ cations and the reduced bi-capped pseudo-Keggin polyoxoanions [PMoVI 8VV 4O 40(VIVO)2]3-. With the aid of hydrogen bonds, these 1D chains extend to 3D supramolecular frameworks. Compounds 2 and 3 are isostructural and consist of the bi-supporting Keggin polyoxoanions [PMoVI 9VV 3O 40(VIVO)2]2- and [M(bix) 4]2+ (M = Zn, Cu) coordination polymer fragments, resulting in the 3D supramolecular frameworks via weak interactions. Compound 4 is composed of the 1D ladder-like chains [Cu(bix)]n n+ which are filled in the 3D supramolecular cavities and stabilize the whole framework structures via hydrogen bonds. Interestingly, 3D architectures have been obviously changed by altering the POM SBUs from pseudo-Keggin to classical Keggin. Here, all these compounds are characterized by elemental analyses, IR, TG analyses and single-crystal X-ray diffractions. In addition, the electrochemical properties and photocatalytic properties of compounds 1-4 have been investigated. © 2011 The Royal Society of Chemistry.

Wang Y.,Chinese Academy of Sciences | Wang Y.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Wang S.,Chinese Academy of Sciences | Wang S.,Northeast Normal University | And 5 more authors.
Journal of Chromatography A | Year: 2013

Core/shell structured magnetic Fe3O4/polydopamine (Fe3O4/PDA) nanoparticles have been successfully synthesized and developed as a magnetic solid-phase extraction (SPE) adsorbent in dispersion mode for the determination of trace polycyclic aromatic hydrocarbons (PAHs) in environmental samples. The Fe3O4/PDA synthetic procedure is simple and involves no organic solvents. Only 20mg of Fe3O4/PDA adsorbents are required to extract PAHs from 500mL water samples. The adsorption attains equilibrium rapidly and analysts are eluted with acetonitrile readily. The extraction efficiency is not influenced by salt concentrations up to 300mM and pH values over the range 4-11. Under optimized conditions, the detection limits of PAHs are in the range of 0.5-1.9ngL-1. The accuracy of the method is evaluated by the recoveries of PAHs from environmental samples. Good recoveries (76.4-107%) with low relative standard deviations from 1.0% to 9.7% are achieved. Comparison study shows that the recoveries of target PAHs are low when they are extracted using traditional SPE method even with the addition of methanol or tetrabutylammonium bromide surfactants in water samples, suggesting great application potential of magnetic SPE method to preconcentrate highly hydrophobic contaminants (such as PAHs) from large volume of water samples. This new SPE method provides several advantages, such as simplicity, low environmental impact, high extraction efficiency, high breakthrough volumes, convenient extraction procedure, and short analysis time. © 2013 Elsevier B.V.

Meng X.,Northeast Normal University | Qin C.,Northeast Normal University | Wang X.-L.,Northeast Normal University | Su Z.-M.,Northeast Normal University | And 2 more authors.
Dalton Transactions | Year: 2011

Immobilization of the chiral salen-metal complex [Mn III(salen) (H 2O) 2ClO 4] on the Keggin-type polyoxometalate (POM) skeletons leads to the isolation of POM derivatives functionalized with chiral salen-metal complexes, which represent the first examples of introducing chiral salen-metal complexes into the POM systems. © The Royal Society of Chemistry 2011.

Gong X.,CAS Dalian Institute of Chemical Physics | Gong X.,Northeast Normal University | Song G.,CAS Dalian Institute of Chemical Physics | Zhang H.,Northeast Normal University | Li X.,CAS Dalian Institute of Chemical Physics
Organic Letters | Year: 2011

A Pd(II)-catalyzed oxidative coupling between pyridine N-oxides and N-substituted indoles via 2-fold C-H bond activation was achieved with high selectivity using Ag2CO3 as an oxidant. © 2011 American Chemical Society.

Guo L.Q.,Northeast Normal University | Guo L.Q.,Jilin Business and Technology College | Shi D.C.,Northeast Normal University | Wang D.L.,Northeast Normal University
Journal of Agronomy and Crop Science | Year: 2010

Eight-week-old seedlings of Puccinellia tenuiflora were stressed by exposure to 1: 1 molar ratio mixtures either of the two neutral salts NaCl and Na2SO4 or of the two alkali salts, NaHCO3 and Na2CO3. To identify the physiological mechanisms involved in this plant's resistance to alkali stress, the relative growth rates, the quantities and compositions of organic acids accumulated and secreted through the roots into the rhyzosphere, the concentrations of inorganic ions, proline and other solutes accumulating in the shoots were measured. The results show that the organic acid constituents in the shoots and roots were much the same. These were predominantly malic acid, oxalic acid, citric acid and succinic acid. The total concentration of organic acids in the shoots increased strongly with increasing alkali stress. However, these either did not increase or they decreased slightly with increasing salt stress. Of the four organic acids, the concentration difference between salt- and alkali-stressed plants was most striking for citric acid. This became the dominant organic acid component under alkali stress. Results show that proline is the main organic osmolyte, whereas the contribution of betaine to osmotic adjustment is insignificant under either salt or alkali stress. The main organic acid accumulated was not only an important organic osmotic regulator, but also an important negative charge contributor, playing important roles in ionic balance and pH adjustment. The concentrations of Na+, K+, Cl- and of organic acid were 80.7% of all solutes under salt stress. The concentrations of Na+, K+, Cl- and of organic acid were 85.4% of all solutes under alkali stresses. The ionic balance was disrupted by the strong increase in Na+ content under alkali stress. This perhaps explains why large amounts of the organic acids were accumulated. The organic acid concentration in the roots was lower than in the shoots. The roots secreted citric acid into the rhyzosphere only under alkali stress, secretion of the other organic acids was not detected. Therefore, citric acid secreted from the roots probably plays an important role in pH adjustment in the rhyzosphere of P. tenuiflora. © 2009 Blackwell Verlag GmbH.

Gong X.,Northeast Normal University | Gong X.,CAS Dalian Institute of Chemical Physics | Zhang H.,Northeast Normal University | Li X.,CAS Dalian Institute of Chemical Physics | Li X.,Nanyang Technological University
Tetrahedron Letters | Year: 2011

Several iridium complexes bearing chelating abnormal N-heterocyclic carbenes (NHCs) are shown to be active catalysts for transfer hydrogenation of ketones or enones, dehydrative C-C coupling between primary and secondary alcohols, and dehydrogenation of benzyl alcohol to benzyl benzoate. In the transfer hydrogenation of acetophenone, abnormal NHC complexes give higher activity than a normal analogue. Dehydrative C-C coupling reactions between primary and secondary alcohols result in β-alkylation of the secondary alcohols, using primary alcohols as the apparent alkylating reagents, and such reactions proceed with high yield and selectivity. These catalytic processes are known to involve metal-mediated temporary borrowing of hydrogen from alcohols and subsequent delivery of the hydrogen to CC and /or CO bonds. © 2011 Elsevier Ltd. All rights reserved.

Liu C.Y.,Northeast Normal University | Xu H.Y.,Northeast Normal University | Ma J.G.,Northeast Normal University | Li X.H.,Northeast Normal University | And 3 more authors.
Applied Physics Letters | Year: 2011

Electrically pumped near-ultraviolet lasing was achieved in a metal/insulator/semiconductor laser diode based on ZnO/MgO core/shell nanowires. The nanowire diode shows higher emission intensity at relatively low operating current density compared with the planar device. The improved efficiency is attributed to enhanced exciton oscillator strength and superior carrier transport properties of single-crystalline ZnO nanowires, and effective surface passivation by MgO coating. Random laser action was confirmed by the calculation of quality factor and the real-time changes of lasing spectra. The results reveal that the MgO coating serves as electron blocking, hole supplying and surface passivation layer for the nanowire heterostructure. © 2011 American Institute of Physics.

Guo W.,U.S. National Institutes of Health | Guo W.,Northeast Normal University | Shugart Y.Y.,U.S. National Institutes of Health
Human Heredity | Year: 2012

With the advent of sequencing technology opening up a new era of personal genome sequencing, huge amounts of rare variant data have suddenly become available to researchers seeking genetic variants related to human complex disorders. There is an urgent need for the development of novel statistical methods to analyze rare variants in a statistically powerful manner. While a number of statistical tests have already been developed to analyze collapsed rare variants identified by association tests in case-control studies, to date, only two FBAT tests-for-rare (described in the updated FBAT version v2.0.4) have applied collapsing methods analogously in family-based designs. For further research in this area, this study aims to introduce three new beta-determined weight tests for detecting rare variants for quantitative traits in nuclear families. In addition to evaluating the performance of these new methods, it also evaluates that of the two FBAT tests-for-rare, using extensive simulations of situations with and without linkage disequilibrium. Results from these simulations suggest that the four tests using beta-determined weights outperform the two collapsing methods used in FBAT (-v0 and-v1). In addition, both the linear combination method (detailed in the FBAT menu v2.0.4) and the multiple regression method (mixing LASSO and Ridge penalties) performed better than the other two beta-determined weight tests we proposed. Following testing and evaluation, we submitted four new beta-determined weight methods of statistical analysis in a computer program to the Comprehensive R Archive Network (CRAN) for general use. © 2012 S. Karger AG, Basel.

Wang J.,Northeast Normal University | Wu L.,Northeast Normal University | Kong J.,Northeast Normal University | Li Y.,Northeast Normal University | Zhang B.,Key Laboratory for Applied Statistics of MOE
Pattern Recognition | Year: 2013

Feature subset selection is often required as a preliminary work for many pattern recognition problems. In this paper, a novel filter framework is presented to select optimal feature subset based on a maximum weight and minimum redundancy (MWMR) criterion. Since the weight of each feature indicates its importance for some ad hoc tasks (such as clustering and classification) and the redundancy represents the correlations among features. Through the proposed MWMR, we can select the feature subset in which the features are most beneficial to the subsequent tasks while the redundancy among them is minimal. Moreover, a pair-wise updating based iterative algorithm is introduced to solve our framework effectively. In the experiments, three feature weighting algorithms (Laplacian score, Fisher score and Constraint score) are combined with two redundancy measurement methods (Pearson correlation coefficient and Mutual information) to test the performances of proposed MWMR. The experimental results on five different databases (CMU PIE, Extended YaleB, Colon, DLBCL and PCMAC) demonstrate the advantage and efficiency of our MWMR. © 2012 Elsevier Ltd.

Wang D.-L.,Northeast Normal University | Wang D.-L.,Anshan Normal University | Xu H.-L.,Northeast Normal University | Su Z.-M.,Northeast Normal University | Xin G.,Anshan Normal University
Physical Chemistry Chemical Physics | Year: 2012

Very recently, two novel Sc 3NC-based cluster fullerenes Sc 3NC@C 80 (Wang et. al. J. Am. Chem. Soc. 2010, 132, 16362) and Sc 3NC@C 78 (Wu et. al. J. Phys. Chem. C 2011, 115, 23755) were prepared and characterized, respectively. Inspired by these findings, the possibility of encapsulating Sc 3NC cluster in the C 84 fullerene is performed using density functional theory (DFT). Firstly, the isolated pentagon rule (IPR) D 2d (23) C 84 fullerene is employed to encase the Sc 3NC cluster: four possible endohedral metallofullerene isomers a-d are designed. The large binding energies (ranging from 163.7 to 210.0 kcal mol -1) indicate that the planar quinary cluster Sc 3NC can be stably encapsulated in the C 84 (isomer 23) cage. Further, we consider the incorporation of Sc 3NC into the non-IPR C s (51365) C 84 cage leading to isomer e and show the high stability of isomer e, which has a larger binding energy, larger HOMO-LUMO gap, higher adiabatic (vertical) ionization potential, and lower adiabatic (vertical) electron affinity than the former four Sc 3NC@C 84 (isomer 23). Significantly, the predicted binding energy (294.2 kcal mol -1) of isomer e is even larger than that (289.2 and 277.7 kcal mol -1, respectively) of the synthesized Sc 3NC@C 80 and Sc 3NC@C 78, suggesting a considerable possibility for experimental realization. The 13C NMR chemical shifts and Raman spectra of this a new endofullerene have been explored to assist future experimental characterization. This journal is © 2012 the Owner Societies.