Urunchi, China

Xinjiang University

Urunchi, China

Xinjiang University is one of the major universities in the Xinjiang Uyghur Autonomous Region, People’s Republic of China, and is a national key university. Established in 1924 and located in Urumqi, Xinjiang University is a comprehensive university with the highest academic level in Xinjiang, under Project 211. Wikipedia.

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Iminniyaz H.,Xinjiang University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2017

We explore the relic abundance of asymmetric Dark Matter in shear-dominated universe in which it is assumed the universe is expanded anisotropically. The modified expansion rate leaves its imprint on the relic density of asymmetric Dark Matter particles if the asymmetric Dark Matter particles are decoupled in shear dominated era. We found the relic abundances for particle and anti-particle are increased. The particle and anti-particle abundances are almost in the same amount for the larger value of the shear factor xe which makes the indirect detection possible for asymmetric Dark Matter. We use the present day Dark Matter density from the observation to find the constraints on the parameter space in this model. © 2016 The Author

The room-temperature solid-state chemical reaction technique has been used to synthesize the silver nanoparticle-loaded semiconductor silver@silver chloride for the first time. It has the advantages of convenient operation, lower cost, less pollution, and mass production. This simple technique created a wide array of nanosized silver particles which had a strong surface plasmon resonance effect in the visible region, and built up an excellent composite structure of silver@silver chloride hybrid which exhibited high photocatalytic activity and stability towards decomposition of organic methyl orange under visible-light illumination. Moreover, this work achieved the control of composition of the silver@silver chloride composite simply by adjusting the feed ratio of reactants. It offers an alternative method for synthesising metal@semiconductor composites. © The Royal Society of Chemistry 2012.

Liu F.,Qinghai Normal University | Feng Z.,Xinjiang University
Holocene | Year: 2012

Our review of recently published climatic proxy sequences shows that the most dramatic climate tranistion of the mid Holocene (~8500-~3500 cal. yr BP) occurred at the middle- to late-Holocene transition at ~4000 cal. yr BP. In northern China, an abrupt climatic shift at ~4000 cal. yr BP was recorded in the eastern margin of the Tibetan Plateau, in the western part of the Chinese Loess Plateau and in the vast Inner Mongolian Plateau. In southern China, the ~4000 cal. yr BP event was also abrupt, but it is expressed as one of several quasi-cyclic events in most of the records. We propose that the cumulative effects of insolation-dictated declining trend in tropical SST and the geologically documented increasing trend of ENSO activity were the first-order causes of the cooling and the associated drying during the past 6000 years. Superimposed on the first-order causes were the second-order causes, i.e. the additive effects of the 'Bond Event 3'-associated lower insolation and the increasingly drying-resulted negative feedback of 'air-land interactions'. The second-order causes made ~4000 cal. yr BP the tipping point when the resultant drying had destroyed many Chinese Neolithic cultures. Our review of published archaeological literature shows that six of the seven well-documented Chinese Neolithic cultures collapsed at ~4000 cal. yr BP with the exception of the Henan Longshan Culture that evolved to the more advanced Erlitou Culture. The indicators of the cultural collapse include (1) the number of archaeological sites was significantly reduced, (2) the quality of the archaeological artifacts of the succeeding culture is lower than that of the preceding culture, (3) more sophisticated architectures disappeared, and (4) agricultural cultures were replaced by pastoralism or by agro-pastoralism in northern China. © The Author(s) 2012.

Two bis(tetrazole) ligands, 1,2-bis(tetrazol-5-ylmethyl)benzene (H 2L 1) and 1,2-bis(tetrazol-5-yl)benzene (H 2L 2), were designed and synthesized, and three new zinc(II) and cadmium(II) coordination polymers, {[Zn 2(L 1) 2(H 2O) 2] 2· 8H 2O} ∞ (1), [Zn 4(L 1) 4] ∞ (2) and {[Cd(L 2)(NH 3) 3]·2H 2O} ∞ (3), were synthesized using the ligands H 2L 1 and H 2L 2 as building blocks. All the complexes were structurally characterized by elemental analyses, IR spectroscopy and X-ray diffraction. Complexes 1 and 3 have infinite one-dimensional (1-D) chain structures, and such 1-D chains structures were linked by complicated hydrogen bonds to form three-dimensional (3-D) supermolecular networks. Complex 2 has a 3-D network structure. In these complexes, the ligands H 2L 1 and H 2L 2 can act as multidentate ligands when coordinating to the metal ions under different conditions, and three coordination modes for the tetrazolate rings have been observed in these complexes. The results show that the variation of the ligand spacers as well as the reaction conditions lead to the formation of complexes with different structures. Furthermore, the fluorescent properties of complexes 1-3 and ligands H 2L 1 and H 2L 2 have been investigated and discussed. © 2012 Elsevier Ltd. All rights reserved.

Kerim A.,Xinjiang University
New Journal of Chemistry | Year: 2014

The aromaticity of porphyrazine (PA) and its three triazoleporphyrazine (TAP) tautomers as well as their metal complex compounds was examined using the TRE (topological resonance energy) and the MRE (magnetic resonance energy) methods. Their local aromaticity was studied using the BRE (bond resonance energy) and the CRE (circuit resonance energy) methods. The relationship between the global and local aromaticity of TAPs and the position of the substituted nitrogen atom is discussed. The results of these calculations are compared with those provided by other aromaticity indices. Our TRE and MRE results indicate that PA and TAPs possess lower global aromaticity than porphyrin. Our BRE and CRE results show that global aromaticity is closely associated primarily with the five-membered rings which contain the -NH- pyrrolic rings, and the [18]-annulene-like conjugation pathway is not crucial for determining the aromaticity of the entire π-system. Moreover, the circuit-current susceptibility (χi) and ring current (RC) were obtained using the graph-theoretical method. The χi and RC results show that all the compounds sustain a diatropic current along the macrocycle and this current is bifurcated when it passes through every five-membered ring. Ring current maps reveal that in the five-membered rings, the ring current prefers to pass through the C-C bond when the ring contains an -NH- group, and through the C-N bond when the ring does not contain an -NH- group. © 2014 the Partner Organisations.

Lei T.,CAS Beijing National Laboratory for Molecular | Xia X.,Xinjiang University | Wang J.-Y.,CAS Beijing National Laboratory for Molecular | Liu C.-J.,Xinjiang University | Pei J.,CAS Beijing National Laboratory for Molecular
Journal of the American Chemical Society | Year: 2014

The charge carrier mobility of p-type and ambipolar polymer field-effect transistors (FETs) has been improved substantially. Nonetheless, high-mobility n-type polymers are rare, and few can be operated under ambient conditions. This situation is mainly caused by the scarcity of strong electron-deficient building blocks. Herein, we present two novel electron-deficient building blocks, FBDOPV-1 and FBDOPV-2, with low LUMO levels down to -4.38 eV. On the basis of both building blocks, we develop two poly(p-phenylene vinylene) derivatives (PPVs), FBDPPV-1 and FBDPPV-2, for high-performance n-type polymer FETs. The introduction of the fluorine atoms effectively lowers the LUMO levels of both polymers, leading to LUMO levels as low as -4.30 eV. Fluorination endows both polymers with not only lower LUMO levels, but also more ordered thin-film packing, smaller π-π stacking distance, stronger interchain interaction and locked conformation of polymer backbones. All these factors provide FBDPPV-1 with high electron mobilities up to 1.70 cm2 V-1 s -1 and good stability under ambient conditions. Furthermore, when polymers have different fluorination positions, their backbone conformations in solid state differ, eventually leading to different device performance. © 2014 American Chemical Society.

Wu B.,Xinjiang University
Match | Year: 2010

The Wiener index W(G) of a connected graph G is the sum of distances of all pairs of vertices in G. We show that for any connected graph G with (5(G) The Wiener index W(G) of a connected graph G is the sum of distances of all pairs of vertices in G. We show that for any connected graph G with δ(G) ≥ 2, W(L(G)) ≥ W(G), with equality if and only if G is a cycle, where L(G) is the line graph of G. We also present lower and upper bounds for JV(L(G)) in terms of a graph invariant called Gutman index of G. As an immediate consequence, a relation between Gutman index and Wiener index of a tree is derived.

Ablajan K.,Xinjiang University
Journal of Mass Spectrometry | Year: 2011

Isoflavone mono-O-glycosides were investigated by electrospray ionization tandem mass spectrometry with a quadrupole linear ion trap mass spectrometer in negative ion mode. Isoflavonoids having different positions of glycosylation or methylation were differentiated according to the relative abundances of Y 0 - and [Y0- H]-⢠ions generated from the [M - H]- ion. It is found that the site of glycosyl or methyl group significantly affects relative abundances of the Y 0 - and [Y0- H]-⢠ions. In addition, the characteristic ion [Y0- 2H]- was observed in the product ion spectrum of genistein 7-O-β-D-glucoside and was also detected, together with the [Y0- CH3] -⢠and [Y0- H - CH3]- ions in the product ion spectra of glycitin and 6-methoxy genistein 7-O-β-D-glucoside. The structures of isoflavonoids can be characterized and identified according to the formation of these diagnostic ions. The results obtained from this investigation can promote the rapid identification of isoflavonoids in crude plant extracts. © 2010 John Wiley & Sons, Ltd.

Yang Z.-X.,Xinjiang University
International Journal of Pattern Recognition and Artificial Intelligence | Year: 2013

In this paper, we propose two Laplacian nonparallel hyperplane proximal classifiers (LapNPPCs) for semi-supervised and full-supervised classification problem respectively by adding manifold regularization terms. Due to the manifold regularization terms, our LapNPPCs are able to exploit the intrinsic structure of the patterns of the training set. Furthermore, our classifiers only need to solve two systems of linear equations rather than two quadratic programming (QP) problems as needed in Laplacian twin support vector machine (LapTSVM) (Z. Qi, Y. Tian and Y. Shi, Neural Netw. 35 (2012) 46-53). Numerical experiments on toy and UCI benchmark datasets show that the accuracy of our LapNPPCs is comparable with other classifiers, such as the standard SVM, TWSVM and LapTSVM, etc. It is also the case that based on our LapNPPCs, some other TWSVM type classifiers with manifold regularization can be constructed by choosing different norms and loss functions to deal with semi-supervised binary and multi-class classification problems. © 2013 World Scientific Publishing Company.

A novel spherical green phosphor, Sr2P2O 7:Ce3+, Tb3+ was prepared by co-precipitation method using a microwave heating system. The synthesis was performed at 1000 °C for 15 min. The phase structure, morphology, photoluminescence properties and thermal stability were investigated. The photoluminescence intensity of green emission from Tb3+ was enhanced remarkably by co-doping Ce 3+ in the Tb3+ solely doped Sr2P 2O7 phosphor because of energy transfer from Ce 3+ to Tb3+ ions. The novel phosphors have excellent thermal stability and remarkable CIE chromaticity coordinates of (0.258, 0.605), indicating its potential application of green emitting phosphor in lighting field. The microwave-assisted co-precipitation method was found to be simple, rapid and advantageous in achieving the required stoichiometry and homogeneity of precursor materials in comparison with the conventional solid state reaction route. © 2013 Elsevier B.V. All rights reserved.

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