Tianjin, China

Tianjin University of Technology is a university in Tianjin, China under the municipal government. It is a public university approved by the State Council in 1981. As an engineering based multi-discipline university, it now has over 16,000 students, 988 teaching faculty and offers 45 Bachelor programs and 39 Master programs in areas such as science, engineering, humanities and management on 2 campuses. Wikipedia.


Time filter

Source Type

Zheng Z.,Tianjin University of Technology | Wang X.,Tianjin University of Technology | Mi W.,Tianjin University
Carbon | Year: 2017

The electric field effects on the electronic structure of g-C2N/XSe2 (X = Mo, W) heterostructures are investigated by first-principles calculations. The g-C2N/MoSe2 heterostructure is an indirect semiconductor at an electric field from −0.1 to 0.3 V/Å. The band gap is 0.66, 0.54, 0.45, 0.39 and 0.34 eV, which almost changes linearly with the electric field. The maximum spin splitting at K point is 188 meV. The g-C2N/WSe2 heterostructure is still an indirect semiconductor at an electric field of −0.1 and 0 V/Å. At an electric field from 0.1 to 0.3 V/Å, the heterostructure with the valence band at Fermi level is a p-type semiconductor, where the band gap is 0.32, 0.26, 0.19, 0.12 and 0.06 eV and the maximum spin splitting at K point is 444 meV. Moreover, near Fermi level, the conduction band mainly comes from monolayer g-C2N, but the valence band comes from XSe2. Our results can bring much significant information on the potential applications in spintronic and field effect devices. © 2017 Elsevier Ltd


Hong T.,Tianjin Chengjian University | Liu Z.,Tianjin Chengjian University | Zheng X.,Tianjin University of Technology | Zhang J.,Tianjin Chengjian University | Yan L.,Tianjin Chengjian University
Applied Catalysis B: Environmental | Year: 2017

In this paper, Co3O4 with different morphologies of nanowires (NWs) and nanolayers (NLs) and Ag modified Co3O4 are prepared on ITO substrate via a facile and low-cost hydrothermal successfully. Co3O4/Ag composite structure served as photocathode applied in photoelectrochemical (PEC) water splitting presents efficient PEC activity for the first time. The enhanced optical and photoelectrochemical performance are characterized, the role of Ag nanoparticles is discussed. The photocurrent densities of Co3O4/Ag NWs and Co3O4/Ag NLs are up to −4.73 mA cm−2 and −4.26 mA cm−2, respectively. The improved PEC performance is attributed to a high light-harvesting efficie ncy, an expanded photoresponse range, accelerated holes mobility and increased interfacial photoelectrons transport of Ag nanoparticles. © 2016 Elsevier B.V.


Wen-Juan Z.,Tianjin University of Technology | Hou-Peng S.,Tianjin University of Technology
IOP Conference Series: Earth and Environmental Science | Year: 2017

Through summarize the status quo of public facilities design to older age groups in China and a variety of factors what influence on them, the essay, from different perspective, is designed to put forward basic principle to sustainable design of public facilities for the aged in the city, and thus further promote and popularize the necessity of sustainable design applications in the future design of public facilities for elderly people. © Published under licence by IOP Publishing Ltd.


Zhang J.,Tianjin University of Technology | Zhu C.,Tianjin University of Technology | Ma Y.,Tianjin University of Technology
Journal of Chemical Thermodynamics | Year: 2017

The densities and viscosities of the ternary mixtures of glycine, L-alanine, L-valine, L-threonine and L-arginine in aqueous maltitol solutions were measured at T = (293.15–323.15) K under the atmospheric pressure. The apparent molar volume (Vφ), the limiting partial molar volume (Vφ 0) and the limiting partial molar volume of transfer (ΔtrVφ 0) were obtained in terms of the measured density, then the viscosity B-coefficient was further calculated by the least-square method. Meanwhile, the partial molar isobaric expansion (E2 0), the isobaric thermal expansion coefficient (α2), the solvation number (nS), the free energies of activation per mole of solvent (Δμ1 0≠) and per mole of solute (Δμ2 0≠) were also calculated. The volumetric and viscometric properties were analyzed and discussed according to the interactions between amino acids and maltitol molecules based on the co-sphere overlap model and the transition state theory. © 2017 Elsevier Ltd


Zhu C.,Tianjin University of Technology
Journal of Molecular Structure | Year: 2017

Metal-organic frameworks (MOFs) have attracted a lot of attention in recent decades. We applied a semi-rigid four-carboxylic acid linker to assemble with Cd(II) ions to generate a novel microporous Cd(II) MOF material. Single crystal X-ray diffraction study reveals the different two dimension (2D) layers can be further packed together with an AB fashion by hydrogen bonds (O4[sbnd]H4⋯O7 = 1.863 Å) to construct a three dimension (3D) supermolecular architecture. The resulting sample can be synthesized under solvothermal reactions successfully, which exhibits high selectivity adsorption of CO2 over CH4 at room temperature. In addition, the obtained sample was characterized by thermal gravimetric analyses (TGA), Fourier-transform infrared spectra (FT-IR), elemental analysis (CHN) and powder X-ray diffraction (PXRD). © 2017 Elsevier B.V.


Wang J.,Tianjin University of Technology | Zhao H.,Tianjin University of Technology | Haller G.,Yale University | Li Y.,Tianjin University of Technology | Li Y.,Yale University
Applied Catalysis B: Environmental | Year: 2017

The development of Cu-chabazite (CHA) catalysts, i.e. Cu-SSZ-13 and Cu-SAPO-34, represents a significant technology breakthrough for the removal of NOx by selective catalytic reduction (SCR) with ammonia. Cu-CHA catalysts show an excellent hydrothermal stability towards high temperature aging and wide active temperature windows for the ammonia SCR reaction. This work summarizes the recent progress in the development of the Cu-CHA catalysts for the NH3-SCR reaction. The state of Cu in the reaction and the preparation methods on the catalytic performance are discussed. The advances in the understanding of the reaction mechanism are reviewed. The hydrothermal stability of the typical Cu-CHA catalysts are compared. © 2016 Elsevier B.V.


Liu D.-D.,Tianjin University of Technology | Gao L.-L.,Tianjin University of Technology | Qin X.-Y.,Tianjin University of Technology
ACM International Conference Proceeding Series | Year: 2016

The ratcheting deformation of articular cartilage can be produced due to the repeated accumulations of compressive strain . The aim of this study was to investigate the ratcheting behavior of articular cartilage under cyclic compression. A series of cyclic compressive tests with different stress amplitudes and stress rates were conducted for pig knee articular cartilage, which was soaked in physiological saline. It is found that the ratcheting strain increases with rising of stress amplitude, while it decreases with rising of stress rate. The initial ratcheting strain of articular cartilage under cyclic compressive load increases rapidly, and then it exhibits a relatively stable status. The change of Young's modulus for cartilage is the same as evolution of ratcheting strain. Simultaneously, the optimized digital image correlation(DIC) technique was applied to study the ratcheting behavior of different layers for cartilage of online soaked under cyclic compression. It is found that the ratcheting behavior of cartilage is dependent on its depth. These results can provide the basis for disease treatment of clinical cartilage and cartilage defect repair. © 2016 ACM.


Wei C.-L.,Tianjin University of Technology | Gao L.-L.,Tianjin University of Technology | Zhang C.-Q.,Tianjin University of Technology
ACM International Conference Proceeding Series | Year: 2016

One of the major functions of bone is to provide structural support. So it is important to study its mechanical behavior. The aim of this study was to investigate the ratcheting behaviors of trabecular bone under cyclic compression and the effect of marrow on the ratcheting strain of trabecular bone. So a series of tests were conducted for the rectangular trabecular bone samples. It is found that the initial ratcheting strain of trabecular under cyclic compressive load increases rapidly, and then its increasing rate keeps on a small value. The relationship between the reduction of marrow and the evolution of mechanical properties of trabecular bone was obtained and the microscopic deformation of tissue was observed with the help of the optimized digital image correlation (DIC) technique. It was found that the marrow can enhance the mechanical strength of trabecular bone to a large extent. Simultaneously, the ratcheting strain of trabecular bone along its depth was basically same. © 2016 ACM.


Zhang Q.,Tianjin University of Technology | Li R.,Tianjin University of Technology | Liu B.,Tianjin University of Technology
Numerical Functional Analysis and Optimization | Year: 2017

In this article, we mainly study the periodic nonuniform dynamical sampling in ℓ2(ℤ) and shift-invariant spaces. We first provide a sufficient and necessary condition for c∈ℓ2(ℤ) which can be reconstructed by its spatial and temporal samples. Then we give a concrete example to show that the sufficient and necessary condition is feasible. Finally, we discuss the periodic nonuniform dynamic sampling problem in shift-invariant spaces. © 2017 Taylor & Francis.


Huang W.,Tianjin University of Technology | Oh S.-K.,University of Suwon | Pedrycz W.,University of Alberta
Proceedings - 2016 Joint 8th International Conference on Soft Computing and Intelligent Systems and 2016 17th International Symposium on Advanced Intelligent Systems, SCIS-ISIS 2016 | Year: 2016

In this paper, we propose a novel architecture of polynomial neural network classifier (PNNC) with the aid of data preprocessing technique and space search optimization, which adopts accelerated convergence mechanism instead of purely random search. Two type of polynomials are adopted for constructing discriminate functions in the PNNC to alleviate the limitation of relatively simple geometry using linear discriminate function in the conventional neural network classifiers. Space search optimization is exploited here to realize structure optimizes and parameter optimize in the design of PNNC. Moreover, data preprocessing techniques are used to reduce the dimension of training data. The proposed PNNC is compared with some well-known classifiers based on several benchmark data sets. Experimental results illustrate the effectiveness of PNNCs. © 2016 IEEE.


Wang L.,Nankai University | Zhang J.,Nankai University | Duan Z.,Tianjin University of Technology | Sun H.,Nankai University
Ecotoxicology and Environmental Safety | Year: 2017

Photodegradation of nonylphenol tri-ethoxylate (NPEO3) in aqueous solution, and the effects of Fe(III) or Fe(II) were studied. The increasing degradation kinetics of NPEO3 were observed when 500 µM Fe(III) or Fe(II) was present in the solutions. Altered formation of NPEO oligomers with shorter EO chains, including nonyphenol (NP), NPEO1 and NPEO2, was observed in water and in solutions containing Fe(III) or Fe(II). The molar percentage yields of NP and NPEO1,2 production from NPEO3 photodegradation were approximately 20% in NPEO3 solution, while NPEO3 solution with Fe(III), this percentage increased to approximately 50%. In solution with Fe(II), the molar balance between the photodegradation of NPEO3 and the production of NP and NPEO1,2 was observed. A luminescent bacterium, Vibrio fischeri, was used to identify changes in the toxicity of NPEO3 solutions during the photodegradation process under different conditions, while dose addition (DA) model was used to estimate the toxicity of products. Toxicity of NPEO3/water solution increased significantly following the irradiation of UVA/UVB mixture. In contrast, obviously decreasing toxicity was observed when NPEO3 underwent photodegradation in the presence of Fe(III). © 2017


Zhang B.,Tianjin University of Technology | Wu L.,Yanshan University | Li Z.,Tianjin University of Technology
RSC Advances | Year: 2017

The crystal structures, phase stability, mechanical and electronic structures of silicon-boron binaries have been investigated systematically using first-principles of pseudopotential calculations. The calculated formation enthalpies of α-SiB3, SiB6 and SiBn follow the sequence: ΔHf (α-SiB3) > ΔHf (SiB6) > ΔHf (SiBn), which is in good agreement with the previous experimental results. Monoclinic SiB6 with P21/m symmetry and hexagonal SiB36 with a B80 unit (a ring linked by diametrically located 2 × B28, 2 × B12) are suggested as the more energetically and mechanically favorable phases by our calculations. The predicted bulk modulus of Si-B binaries is between 120 and 180 GPa, while there is a dramatic drop for two kinds of α-SiB3 in the shear modulus from 130.3 GPa (SiB3) to 71.1 GPa (SiB4). We infer that the additional centered boron atoms, located long the spatial diagonal in SiB4, is responsible for the weakness along this direction. In addition to β-SiB3, the new proposed P21/m-SiB6 and R3m-SiB6 is found to be semiconducting with 0.41 eV indirect and 1.654 eV direct band gap, respectively. There is no band gap provided by band structures of SiB4 and SiB36, as well as their DOS values are quite large at Fermi level, indicating they are energetically unstable under 0 K and GPa. © The Royal Society of Chemistry.


Wang H.,Tianjin University of Technology | An X.,Tianjin University of Technology | Deng X.,Tianjin University | Ding G.,Tianjin University of Science and Technology
Electrophoresis | Year: 2017

A facile, mild method for the preparation of teicoplanin (TE) modified Fe3O4 microparticles (MPs) employing polydopamine (PDA) layer as a versatile secondary reaction platform was developed. The synthesized magnetic MPs (Fe3O4@PDA@TE) were characterized by various characterization techniques, such as TEM, zeta potential etc, to affirm the successful modification of TE to magnetic Fe3O4 MPs. Using the as-synthesized materials as chiral adsorbents, efficient chiral separation of representative racemic compounds was successfully achieved. Due to the magnetic responsivity, the materials were easily isolated from the racemic solutions under an external magnetic field and could be readily reused for at least three times. Thus, the well-prepared functional magnetic MPs have great potential in preparative chiral separation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Song Y.,Tianjin University | Wang X.,Tianjin University of Technology | Mi W.,Tianjin University
Physical Chemistry Chemical Physics | Year: 2017

The semimetallic WTe2 has sparked intense interest owing to the non-saturating magnetoresistance, pressure-driven superconductivity and possession of type-II Weyl fermions. The unexpected and fascinating quantum properties are thought to be closely related to its delicate Fermi surface and a special electron-hole-pocket structure. However, in the single-layer limit, the electron-hole-pocket structure is missing owing to the lack of interlayer interaction. Herewith, we demonstrate that 3d transition-metal adsorption is an effective method to modify the electronic properties of monolayer WTe2 by density functional theory. Spin-splitting and spin-degenerate bands are realized in Ti-, V-, Cr-, Mn-, Fe-, and Co- and Sc-, Ni-, Cu-, and Zn-adsorbed systems, respectively. Especially, the reemergence of the electron-hole pockets appears in the Ni-adsorbed system. The calculated results are robust against inclusion of spin-orbit coupling and Coulomb interaction. © the Owner Societies 2017.


Tian F.,Tianjin University of Technology | Li H.,Tianjin University of Technology | Li M.,Tianjin University of Technology
Micro and Nano Letters | Year: 2017

Three-dimensional vertical graphene flowers were fabricated using a simple, low-cost, and efficient chemical vapour deposition method with Ni(NO3)2 as a catalyst precursor and methane as a carbon precursor. Graphene flowers of up to 10 μm in size with petals of two to seven layers of graphene were obtained. The growth of the vertically aligned graphene flowers was attributed to a columnar growth mechanism. Numerous micropores were observed between the flower petals and irregular mesopores were observed in the interconnected flowers. The charge-transfer resistance of a graphene flower/Ta film was 30.8 ω. The graphene flowers acted as charge carriers, reducing the charge recombination rate and enhancing electron transport. The vertical graphene flowers showed significant photoelectrocatalytic activity for the degradation of phenol. © 2016 The Institution of Engineering and Technology.


Chen J.E.,Tianjin University of Technology | Zhang W.,Beijing University of Technology | Yao M.H.,Beijing University of Technology | Liu J.,Tianjin University of Technology
Composite Structures | Year: 2017

In this work, the dynamics of a truss core sandwich beam with NES (nonlinear energy sink) device are investigated. Based on the principle of nonlinear TET (targeted energy transfer), an NES device is placed in the interior of a sandwich beam to suppress vibration of the beam. The governing equation of motion for the sandwich beam with NES device attached is derived. The vibration responses of the system are analyzed under impulse and harmonic loads. Feasibility of the vibration suppression scheme is demonstrated by investigating the relation between the mass of the NES device and suppressing effect as well as the relative motion between the sandwich beam and the NES device. In addition, the influences of the NES parameters on the suppressing effect are studied. It is worth noting that the vibration suppression is enhanced with increasing the damping of NES when the system is excited by harmonic loads and with decreasing the damping when the system is excited by impulse loads. The influence of the nonlinear characteristic of spring on the vibration suppression depends on the selection of the other parameters of the NES. © 2017 Elsevier Ltd


Zhu P.,Tianjin University of Technology | Ma X.,Tianjin University of Technology | Huang Z.,Tianjin University of Technology
Infrared Physics and Technology | Year: 2017

Integration of infrared and visible images is an active and important topic in image understanding and interpretation. In this paper, a new fusion method is proposed based on the improved multi-scale center-surround top-hat transform, which can effectively extract the feature information and detail information of source images. Firstly, the multi-scale bright (dark) feature regions of infrared and visible images are respectively extracted at different scale levels by the improved multi-scale center-surround top-hat transform. Secondly, the feature regions at the same scale in both images are combined by multi-judgment contrast fusion rule, and the final feature images are obtained by simply adding all scales of feature images together. Then, a base image is calculated by performing Gaussian fuzzy logic combination rule on two smoothed source images. Finally, the fusion image is obtained by importing the extracted bright and dark feature images into the base image with a suitable strategy. Both objective assessment and subjective vision of the experimental results indicate that the proposed method is superior to current popular MST-based methods and morphology-based methods in the field of infrared-visible images fusion. © 2017 Elsevier B.V.


Ding L.,Tianjin University of Technology | Hu S.,Tianjin University of Technology | Quan X.,Luan Vocation Technology College | Shen J.,Tianjin University of Technology
Surface and Coatings Technology | Year: 2017

Laser cladding VN alloy/Co-based composite coatings on a mild steel substrate were heat treated at 650 °C for 3 h and 5 h, respectively. Effect of heat treatment on microstructure and wear resistance of the composite coatings was investigated systematically by optical microscopy, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, micro-hardness testing and wear testing. The results showed that as-laser cladded and heat treated VN alloy/Co-based composite coatings were all composed of γ-Co, Cr23C6, σ-FeV, Co5.47N and VN phases. The intensities of γ-Co diffraction peaks were reduced gradually and the intensities of Cr23C6 and VN diffraction peaks were increased gradually with the increasing of heat treatment time. Lots of short rod-shaped dendrites and more uniform equiaxed grains exhibited in the composite coatings after heat treatment. The microhardness and wear resistance of VN alloy/Co-based composite coatings were reduced slightly after heat treatment for 3 h. The microhardness and wear resistance of the composite coatings were improved by 6.71% and 9.82%, respectively, for heat treatment for 5 h. The wear mechanism of three composite coatings was all the abrasive wear. © 2017


Che G.,Tianjin University of Technology
Revista Tecnica de la Facultad de Ingenieria Universidad del Zulia | Year: 2016

Considering the shortcomings of heavy workload, time-consuming and laborious in common soil erosion observation and experimental methods, Jixian district in Tianjin was selected as the research area in this paper. The multi-factor comprehensive method in the second national soil erosion remote sensing survey is adopted. This paper uses the TM data of 2004 and Landsat-8 data and DEM data in 2015 of this region, according to the Soil Erosion Classification and Grading Standard (SL 190-2007) issued by the Ministry of Water Resources. The soil erosion intensity grading map of two periods in Jixian was obtained and the annual average erosion modulus was calculated. Based on the TM images in 2004 and Landsat-8 data in 2015, DEM data were employed in the study. The results showed that the soil erosion in Jixian district was mildly eroded in the recent ten years, although the average annual erosion modulus has declined, it is still necessary to pay attention to the areas above the strength erosion.


Zhen M.,Tianjin University of Technology | Zhen M.,Nankai University | Liu L.,Nankai University | Wang C.,Tianjin University of Technology
Microporous and Mesoporous Materials | Year: 2017

Transition-metal oxides have been widely explored as the anode materials for lithium-ion batteries (LIBs) because of its low cost and high energy/power density. However, the electrode pulverization and capacity fading during cycling lead to poor cycling performance. Herein, ultrathin ZnCo2O4 nanosheets with desired mesoporosity and high surface area are prepared by a facile hydrothermal approach. Such ZnCo2O4 nanostructures show excellent lithium storage performance as anode materials for LIBs. At a current density of 1 A g−1, the ultrathin ZnCo2O4 nanosheets present an initial specific capacity of 1251 mAh g−1 and the specific capacity remains at ∼810 mAh g−1 even after 200 discharge–charge cycles. © 2017 Elsevier Inc.


Shang X.,Tianjin University of Technology | Zhu Y.,Tianjin University of Technology | Li Z.,Tianjin University of Technology
Applied Surface Science | Year: 2017

In this paper, two kinds of silane coupling agents, namely 3-aminopropyl triethoxysilane (KH550) and 3-mercaptopropyl trimethoxysilane (KH590), were adopted as preliminary modifiers to improve the hydrophobic surface properties of silicon carbide (SiC) powder for the first step. The factors that influence the modification effects were investigated by measuring the contact angle. The results showed that KH590 has a better effect than KH550 for the hydrophobic modification of SiC, and the contact angle improved most after SiC powder was reacted with 0.3 g KH590 at 75 °C in aqueous/alcohol solution for 4 h. On account of further enhancement of hydrophobicity, the study was focused on utilizing nucleophilic substitution between KH590 and hexadecyl iodiele to extend the length of alkyl chain. Compared with using KH590 alone, SiC powder modified by KH590 and hexadecyl iodiele showed better water resistance with an increase of contact angle from 106.8° to 127.5°. The Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectra (XPS) as well as X-ray diffraction (XRD) analysis results showed that KH550/KH590 and hexadecyl iodiele can be covalently bonded to the surface of SiC powder without altering its crystal configuration. This methodology may provide a new way of the modification of inorganic materials in further. © 2016 Elsevier B.V.


Wang L.,Tianjin University of Technology | Wang Y.,Tianjin University of Technology | Lian J.,Tianjin University of Technology
IOP Conference Series: Materials Science and Engineering | Year: 2017

Urban sewage sludge with complicated composition produce largely each year, pollution problem and resource utilization has increasingly become the focus of attention. Sewage sludge is utilized to prepare adsorbent that is a new type method. Agricultural stalks was added to material (urban sewage sludge) and activator (ZnCl2), calcined under the condition of no inert gas, and obtained domestic sludge activated carbon. The properties were measured by iodine adsorption value and BET, discussed influence factors of sludge activated carbon preparation, including activator concentration, solid-liquid ratio, calcific temperature and calcific time. The best process condition of orthogonal experiment had explored that activated time is 10 minutes, calcific temperature is 350°C, the activator concentration ZnCl2 is 3 mol/L and the mixing ratio of raw materials and activator is approximately 1:5. The iodine adsorption value and the optimal BET of as-obtained domestic sludge activated carbon is 445.06 mg/g, 525.31m2/g, respectively. © Published under licence by IOP Publishing Ltd.


Zhang D.L.,Tianjin University | Zhang D.L.,Tianjin University of Technology | Yang X.F.,City University of Hong Kong
Optics InfoBase Conference Papers | Year: 2016

Near-stoichiometric titanium indiffused LiTaO3 strip waveguides have been fabricated and characterized. The waveguides are polarization-insensitive, and the propagation losses are ~ 0.2 dB/cm and 0.3 dB/cm for TE and TM modes, respectively. © OSA 2016.


Cui L.,Tianjin University of Technology | Su J.,Tianjin University of Technology | Li X.,Tianjin University of Technology
Optics InfoBase Conference Papers | Year: 2016

We demonstrate that after distributing in few mode fibers, the measured visibility of entanglement depends on the degree of freedom of entanglement and the spatial mode of photon pairs in transmission fibers. © OSA 2016.


Li J.,Shijiazhuang Mechanical Engineering College | Xia Y.,Beijing Institute of Technology | Qi X.,Shijiazhuang Mechanical Engineering College | Gao Z.,Cleveland State University | Gao Z.,Tianjin University of Technology
IEEE Transactions on Industrial Electronics | Year: 2017

Active disturbance rejection control (ADRC) was originally given in a nonlinear gain structure to better accommodate the dynamic uncertainties and disturbances. However, the resulting complexity in a theoretical analysis and in the parameter tuning inhibits the applications of an ADRC. ADRC was linearized and parameterized for a practical convenience. Since linear ADRC (LADRC) and nonlinear ADRC (NLADRC) each has its own advantages and disadvantages, choosing between LADRC and NLADRC is rather difficult. As a matter of fact, there is a lack of quantitative analysis and comparison between LADRC and NLADRC. This paper first gives an easy solution in the parameter tuning of the nonlinear extended state observer, followed by a quantitative analysis and comparison study on LADRC and NLADRC; then, an LADRC/NLADRC switching control (SADRC) scheme is proposed and its stability is analyzed; finally, the SADRC scheme is verified by experiment using the ball-beam platform. The proposed SADRC takes the advantage of the additional performance improvement associated with the NLADRC, but make it easier to use. © 2016 IEEE.


Zhang G.,Tianjin University of Technology | Yang Z.,Tianjin University of Technology | Zhang W.,Tianjin University of Technology | Wang Y.,Tianjin University of Technology
Journal of Materials Chemistry A | Year: 2017

The direct methanol fuel cell is an emerging energy conversion device for which Pt is considered as the state-of-the-art anode catalyst. Herein, we show that the activity and stability of Pt for methanol oxidation can be significantly enhanced using Mo-doped CeO2 (Ce1-xMoxO2-δ) solid solutions as co-catalysts. X-ray photoelectron spectroscopy (XPS) reveals a strong electronic interaction between Ce1-xMoxO2-δ and Pt in Pt/Ce1-xMoxO2-δ-C catalysts. Among all Pt/Ce1-xMoxO2-δ-C catalysts, the catalyst with a Ce/Mo atomic ratio of 7/3 (Pt/Ce0.7Mo0.3O2-δ-C) exhibits the highest activity, up to 1888.4 mA mgPt -1, which is one of the best results reported so far. A direct methanol fuel cell incorporating the Pt/Ce0.7Mo0.3O2-δ-C as the anode catalyst exhibits a maximum power density of 69.4 mW cm-2, which is 1.8 times that of an analogous fuel cell using the commercial Pt/C-JM as the anode catalyst. © 2017 The Royal Society of Chemistry.


Li Y.-L.,Tianjin University | Li J.,Tianjin University | Deng J.,Tianjin University of Technology
Advanced Synthesis and Catalysis | Year: 2017

A facile synthetic approach to a series of difluoromethyl ketones from β-ketoacids has been described. This transformation is achieved through the straightforward decarboxylative difluorination of β-ketoacids in the absence of any catalyst. Furthermore, the resulted difluoromethyl ketones can be easily converted into corresponding difluoromethylated building blocks for pharmaceuticals and materials. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.


Du Y.,Tianjin University of Technology | Yu A.,Tianjin University of Technology | Jia J.,Tianjin University of Technology | Zhang Y.,Tianjin University of Technology | Meng X.,Tianjin University of Technology
Chemical Communications | Year: 2017

A protocol for the direct functionalization of N-H/α,α,β,β-C(sp3)-H of piperidine without any metal or external oxidants is reported. This reaction is promoted by 4-(trifluoromethyl)benzoic acid via an azomethine ylide intermediate. This is a simple method for the synthesis of spirooxindoles bearing 3-substituted oxindole moieties. © The Royal Society of Chemistry.


Yao J.,Tianjin University of Technology | Lin B.,Tianjin University of Technology | Guo Y.,Tianjin University of Technology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2017

Different from common thin-walled workpiece, in the process of milling of large-size thin-walled workpiece chatter in the axial direction along the spindle is also likely to happen because of the low stiffness of the workpiece in this direction. An analytical method for prediction of stability lobes of milling of large-size thin-walled workpiece is presented in this paper. In the method, not only frequency response function of the tool point but also frequency response function of the workpiece is considered. © 2017 SPIE.


Bai Q.,Qufu Normal University | Chen M.,Concordia University at Montréal | Xu L.,Tianjin University of Technology
International Journal of Production Economics | Year: 2017

This paper studies a two-echelon sustainable supply chain system with deteriorating items consisting of one manufacturer and one retailer under carbon cap-and-trade regulation. The time-varying demand in this system is affected by three endogenous variables that include promotional effort provided by the retailer, product selling price, and the sustainable level determined by the manufacturer. A centralized model and a decentralized model are first formulated and compared. The results show that cooperation between the manufacturer and retailer may lead to higher profit and lower carbon emissions. We then propose a revenue and promotional cost-sharing contract and a two-part tariff contract to coordinate this system. A numerical example and sensitivity analysis with several key parameters are presented to illustrate the effectiveness of the contracts. The results show that both contracts can lead to perfect coordination, while the two-part tariff contract is more robust than the revenue and promotional cost-sharing contract. © 2017 Elsevier B.V.


Sun M.,Tianjin University | Zheng D.,Tianjin University | Wang X.,Tianjin University of Technology | Mi W.,Tianjin University
Journal of Physical Chemistry C | Year: 2017

The use of molecular modification on magnetism has gained considerable interest in the development of multifunctional molecular spintronics. Such hybrid structures of nonmagnetic molecules and ferromagnetic metals manifest great promises of producing novel electric and magnetic features. The external electric field effect on the magnetism of C6H6-adsorbed Fe3O4(001) surface is elucidates by density functional theory calculations. The reduced magnetic moments of partial octahedral Fe atoms in the first layer break the spherical spatial spin density distribution. Such modification that is independent of the direction of electric field can be attributed to the charge redistribution as a result of screening effect, which changes orbital occupancy in unpaired octahedral Fe-d electrons near EF accompanied by a spin flip. Furthermore, octahedral Fe atom underneath C atom changes only as the applied field is large enough. Additionally, it is shown that the study of modulation on surface magnetism through external electric field is expected to excite a new area in molecular spintronics, such as the potential applications in electrically controlled magnetic data storage. (Figure Presented). © 2017 American Chemical Society.


Hou P.,University of Jinan | Zhang H.,Tianjin University of Technology | Zi Z.,CAS Qingdao Institute of Bioenergy and Bioprocess Technology | Zhang L.,Tianjin University of Technology | Xu X.,University of Jinan
Journal of Materials Chemistry A | Year: 2017

The core-shell structure has been extensively utilized to develop new functional materials and become a research focus in materials science recently. Over the past decades, the requirements of high-capacity, high-rate, long cycle-life and superior safety have been the main driving force for the advance of cathode materials for lithium-ion batteries (LIBs). Correspondingly, the concept of the core-shell structure is introduced to prepare the above desired cathodes. After that, the concentration-gradient structure is further exploited to overcome the drawbacks of the core-shell structure. The co-precipitation route is more suitable for synthesizing core-shell and concentration-gradient structures compared with other methods, such as sol-gel and spray-drying. More importantly, it is capable of producing large-scale cathodes in the domain of LIBs. In this review, we first illustrate the design principles and formation mechanism of core-shell and concentration-gradient cathode materials; then the recent advances in co-precipitation preparation core-shell and concentration-gradient cathodes for high-energy, high-power, long-life and safe LIBs are summarized. Moreover the structural evolution during cycles to uncover the origin of these improved performances is also analysed. Based on these achievements thus gained, we propose a new strategy to enhance the performances of cathodes. Finally, the remaining challenges including fundamental investigation, commercialized application and present possible solutions are also discussed. © The Royal Society of Chemistry.


Piao S.,Tianjin University of Technology | Li J.,Tianjin University of Technology | Li J.,Tianjin University
CIE 2016: 46th International Conferences on Computers and Industrial Engineering | Year: 2016

Under the Background of Internet+, aiming at the asymmetry in the process of service supply and demand information and the low public participation in the environmental protection, a cloud service platform of crowdsourcing was presented. The problem of environmental service industry was analysed based on the analysis of process. After describing the general idea and technology system of platform, the whole architecture of cloud platform was constructed on the basis of technology supporting system. Finally, taking Tianjin as an example, based on the analysis of operation process of platform information, a preliminary application was discussed from the business centre, cloud management centre and trading process. This study provides some support for promoting efficiency of environmental protection service and reference in crowdsourcing cloud service platform.


Xu X.,Tianjin University of Technology | Shi J.,Tianjin University of Technology
CIE 2016: 46th International Conferences on Computers and Industrial Engineering | Year: 2016

With the improvement of science technology and productivity, IE had made a rapid development greatly. Its application area and research content have been expanded and enriched constantly. Neuro-Industry Engineering (Neuro-IE) is established upon Cognitive Neuroscience and traditional Industry Engineering (Traditional IE). And it becomes known to people after it was an emerging interdisciplinary science. Thus, a great deal of researches are done in many areas. This paper reviewed the three development stages of Industry Engineering briefly and gave a detailed account of the conception of Neuro-IE. Meanwhile, this paper detailedly introduced application and results of research on Neuro-IE in some areas.


Liu L.,Tianjin University of Technology | Niu Z.,Nankai University | Chen J.,Nankai University
Nano Research | Year: 2017

As promising candidates for energy-storage devices, supercapacitors (SCs) have attracted considerable attention because of their unique features, such as their high power density, outstanding rate capability, excellent cycling performance, and safety. The recent boom in portable electronic devices requires high-performance SCs that are flexible, simplified, thin, and integrated. Tremendous efforts have been directed towards the design and integration of planar micro-SCs (MSCs) based on different active electrode materials by various methods. This review highlights the recent developments in the device design of flexible planar MSCs and their integration with other electronic devices. The current challenges and future prospects for the development of flexible MSCs are also discussed.[Figure not available: see fulltext.] © 2017 Tsinghua University Press and Springer-Verlag Berlin Heidelberg


Han T.,Tianjin University of Technology | Wang Z.,Tianjin University of Technology | Yang X.,Tianjin University of Technology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

Kinds of factors such as illumination and hand gestures would reduce the accuracy of dorsal hand vein recognition. Aiming at single hand vein image with low contrast and simple structure, an algorithm combining Gabor multi-orientation features fusion with Multi-scale Histogram of Oriented Gradient (MS-HOG) is proposed in this paper. With this method, more features will be extracted to improve the recognition accuracy. Firstly, diagrams of multi-scale and multi-orientation are acquired using Gabor transformation, then the Gabor features of the same scale and multi-orientation will be fused, and the features of the correspondent fusion diagrams will be extracted with a HOG operator of a certain scale. Finally the multi-scale cascaded histograms will be obtained for hand vein recognition. The experimental results show that our method not only improve the recognition accuracy but has good robustness in dorsal hand vein recognition. © 2016 SPIE.


Zhang X.,Tianjin University of Technology | Yang X.,Tianjin University of Technology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

Focusing properties of the vector vortex-bearing beams are investigated theoretically by vector diffraction theory. Simulation results show that the intensity distribution in focal region can be altered considerably by adjusting topological charge m and the numerical aperture(NA) of the focusing optical system. Focal pattern evolves from one focal spot to two overlapped intensity peaks1.The two overlapped intensity peaks separate with increasing topological charge m, which leads to the focal splitting. And focal split appears in focal evolution show that the topological charge of the vector vortex-bearing beams influences the focal intensity distribution considerably, and some novel focal patterns appear. © 2016 SPIE.


Qin N.,Tianjin University of Technology | Hao P.Z.,Tianjin Institute of Urban Construction
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2017

The paper discusses the system characteristics of an untreated sewage source heat pump in winter. In this system, the sewage enters into the evaporator directly. The variable parameters to control the system contain the sewage temperature at evaporator inlet and the water temperature at condenser inlet. It is found that most parameters, except the condensation heat transfer coefficient, change in the form of sine wave the same as the sewage temperature at inlet. The heating load and consumed power are 12.9kW and 3.45kW when the sewage temperature at inlet is 13°C. COP is about 3.75 in the range of the sewage temperature at inlet of 12-13°C. © 2017 SPIE.


Tong Z.,Tianjin University of Technology | Wang Y.,Tianjin University of Technology | Guo Z.,Tianjin University of Technology
ICOCN 2016 - 2016 15th International Conference on Optical Communications and Networks | Year: 2016

In coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems, the high peak to average power ratio (PAPR) will causes serious signal degradation through the nonlinearity of modulator and fiber. In this paper, the PAPR reduction techniques based on wavelet packet transform (WPT) for CO-OFDM systems are proposed, the WPT is used instead of traditional fast Fourier transform (FFT). Moreover, two efficient PAPR reduction techniques are combined with the proposed WPT-OFDM. Simulation results show that the PAPR of proposed scheme combined with selective mapping (SLM) and partial transmit sequence in combination with clipping (clipping PTS) are optimized compared to the traditional FFT. Under the same conditions, while maintaining good performance in the BER compared to ordinary FFT. And the proposed WPT system provides the high spectral efficiency transmission without CP. © 2016 IEEE.


Xi Z.,Tianjin University of Technology | Feng Z.,Tianjin University of Technology | Li A.,Tianjin University of Technology
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2017

For the control of pulverized coal, we propose a dust suppressant by applying a blend of mixed polyethylene oxide (g-PEO) and sodium dodecyl sulfate (SDS). In our experimental study, the thermal characteristics, critical micelle concentration (CMC), wettability and adhesion of the dust suppressant are investigated. It was found that g-PEO had a low fusing temperature and its combustion temperature was close to that of coal, thus, the solution containing g-PEO applied coal dust control did not affect the use of the coal. Based on steady-state fluorescence using pyrene as a fluorescent label, quantitative analysis revealed that the CMCs of g-PEO and SDS were 1 and 20 g/L in g-PEO&SDS solution, respectively. The solution containing SDS had the best wettability, but it only had a short-term effect. The solution containing g-PEO showed negligible wetting ability to wet coal dust. The solution containing g-PEO&SDS had better wetting ability and adhesion. Scanning electron microscopy showed that the coal dust covered by g-PEO&SDS on its surface could form a thin layer of armor by holding the particles together after air-drying. It was concluded that the g-PEO&SDS solution containing g-PEO for 1 g/L and SDS for 20 g/L could suppress coal dust and maintain a long-term effect. © 2017 Elsevier B.V.


Ma B.,Tianjin University of Technology | Wei Y.,Tianjin University of Technology
Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument | Year: 2016

In the course of life about modern people, the use of human face to express emotion, pass individual thought, expression of mutual exchange, the human face has become the most direct and important means of expression. With the development of image technology, face recognition technology has attracted people's attention. In recent years in the field of face recognition technology and theory research, and select the AdaBoost algorithm to achieve integration, in order to achieve better recognition results. In the recognition process, according to the characteristics of images to grayscale and equalization preprocessing, improve image quality, improve image resolution and speed; feature classifier selected Haar feature classification; using SIFT algorithm for comparison algorithm will be compared with the matching image in the image database, complete the process of face recognition. Finally, a simple face recognition system is designed and implemented in this paper. The algorithm is used to complete the calculation. The accuracy and effectiveness of the method and system are verified by experiments. © 2016, Science Press. All right reserved.


Liu P.,Tianjin University of Technology | Lin B.,Tianjin University of Technology | Zhang X.,Tianjin University of Technology | Li Y.,Tianjin University of Technology
Applied Optics | Year: 2017

A new grinding technology called fluid hydrodynamic fixed abrasive grinding (abbreviated as FHFAG process) is being proposed in this research. It combines the fixed abrasive grinding process and the fluid hydrodynamic theory. This research will examine the feasibility of applying the innovative process as an ultra-precision machining method for hard and brittle materials such as fused silica glass and silicon. It aimed to turn fixed abrasive grinding processing into a kind of deterministic surfacing processing method. Besides, the method could improve the machining efficiency and machining accuracy at the same time. Specifically, a thin liquid film between the grinding pad and the workpiece is introduced. The cutting depth based on one single grinding pad with a settled particle size can be controlled by controlling the thickness of the liquid film. From the machining mechanism, the grinding tool's rotary speed and the original input pressure dominate the deterministic properties of the process. A special self-balancing device and a special fluid supply method which supply the grinding liquid from the center of the motorized spindle are proposed to realize the new processing technology. The grinding pad can float on the workpiece steadily from a preliminary experiment result. It is clearly demonstrated that the FHFAG process can be used as a deterministic processing method if the identified working parameters are well controlled. © 2017 Optical Society of America.


Yu Q.,Tianjin University of Technology | Wang L.,Tianjin University of Technology
Proceedings - 2016 9th International Congress on Image and Signal Processing, BioMedical Engineering and Informatics, CISP-BMEI 2016 | Year: 2016

In order to solve multi-class classification problem in real world, we improved TSVM in this paper. We combined LSTSVM with partial binary tree to improve classification efficiency. Binary tree hierarchy can solved the inseparable regional issues in OVO-SVM and OVA-SVM classification. Experimental results show that it improved the classification accuracy. It also has better speed-up ratio than the OVO-SVM, OVA-SVM. It also reduced the training time. The time advantage is more obvious, especially the data set is large. © 2016 IEEE.


Tang L.,Tianjin University of Technology | Li Q.,Tianjin University of Technology
Proceedings - 2016 9th International Congress on Image and Signal Processing, BioMedical Engineering and Informatics, CISP-BMEI 2016 | Year: 2016

Objective: Using High-resolution MRI technology to observe and measure inner ear and vestibular cochlear nerve (VCN) of congenital sensorineural deafness (CSNHL) children. Explore the relationship between children with congenital sensorineural hearing nerve deafness VCN development and age. © 2016 IEEE.


Li Q.,Tianjin University of Technology | Wang Z.,Tianjin University of Technology
Proceedings - 2016 9th International Congress on Image and Signal Processing, BioMedical Engineering and Informatics, CISP-BMEI 2016 | Year: 2016

Early hearing deprivation could affect the development of auditory, language and vision ability. Insufficient or no stimulation of the auditory cortex during the sensitive periods of plasticity could lead to abnormal function of hearing and language development. Some of vision and executive functions were enhanced due to the loss of hearing. Twenty-three (23) children (mean age 24.18±14.00 month). with congenital severe sensorineural hearing loss and 17 age and sex matched normal hearing subjects were recruited and the resting state fMRI was performed on a 3.0 T superconductive scanner. The amplitude of low frequency fluctuations (ALFF) and regional homogeneity (ReHo) of the functional brain area were compared between deaf children and normal subjects. Compared with normal hearing subjects, decreased ALFF was observed in auditory and language related cortex. Increased ALFF was observed in vision related cortex. Decreased ReHo was observed in auditory and language related cortex. Increased ReHo was observed in vision related cortex. ALFF value in language related cortex, Brodmann area 45 (BA45) was negatively correlated with age in hearing loss children (r=-0.568, p=0.005). ALFF value in BA39 was positively correlated with age in deaf children (r=0.574, p=0.004). ALFF value in BA47 was positively correlated with age in normal subjects (r=-0.229, p=0.029). Abnormal ALFF and ReHo in deaf children could reflect the reshape of function of brain area related with auditory, language and vision ability. © 2016 IEEE.


Yu Q.,Tianjin University of Technology | Ding Z.,Tianjin University of Technology
Proceedings - 2016 9th International Congress on Image and Signal Processing, BioMedical Engineering and Informatics, CISP-BMEI 2016 | Year: 2016

In order to solve the problem that FCM algorithm is sensitive to initial clustering center, we use Canopy algorithm to conduct the quick rough clustering. In the meantime, to avoid the blindness of Canopy algorithm, we put forward an improved Canopy-FCM algorithm based on max-min principle. In allusion to the problem that FCM algorithm has high time complexity, this article use the parallel computing frame of MapReduce to design and realize the improved Canopy-FCM algorithm. Experimental result shows: improved Canopy-FCM algorithm based on MapReduce has better clustering quality and running speed than the Canopy-FCM and FCM algorithm based on MapReduce, and the improved Canopy-FCM algorithm based on Hadoop has better speed-up ratio than Canopy-FCM based on Standalone mode. © 2016 IEEE.


Zhang X.J.,Tianjin University | Mi W.B.,Tianjin University | Wang X.C.,Tianjin University of Technology | Bai H.L.,Tianjin University
Journal of Alloys and Compounds | Year: 2014

The electronic structure and magnetism of RE (RE = La, Ce, Pr, Nd and Eu) doped ZnO are investigated by first-principles calculations. La doping can result in a diamagnetic ground state. The total magnetic moment of a single Ce, Pr, Nd and Eu doped ZnO are 0.92, 1.97, 3.01 and 6.82 μBin a 2 × 2 × 2 supercell, respectively, followed by the appearance of spin splitting for initially O p and Zn s, d states at low energy range in the valence band and the localized magnetic influence of RE on ZnO. Doping of La and Ce is more stable than that of Pr, Nd and Eu. The ground states of Pr, Nd and Eu dopants at Zn sites are weakly antiferromagnetic, but the ground state of Ce dopants is ferromagnetic. Meanwhile, n-type doping is observed in Ce, Pr and Nd-doped ZnO systems as the donor states are near the conduction bands. © 2014 Elsevier B.V. All rights reserved.


Zhang P.,Tianjin University of Technology | Zhang J.,Tianjin University of Technology | Gong J.,Tianjin University of Technology
Chemical Society Reviews | Year: 2014

Solar energy utilization is one of the most promising solutions for the energy crises. Among all the possible means to make use of solar energy, solar water splitting is remarkable since it can accomplish the conversion of solar energy into chemical energy. The produced hydrogen is clean and sustainable which could be used in various areas. For the past decades, numerous efforts have been put into this research area with many important achievements. Improving the overall efficiency and stability of semiconductor photocatalysts are the research focuses for the solar water splitting. Tantalum-based semiconductors, including tantalum oxide, tantalate and tantalum (oxy)nitride, are among the most important photocatalysts. Tantalum oxide has the band gap energy that is suitable for the overall solar water splitting. The more negative conduction band minimum of tantalum oxide provides photogenerated electrons with higher potential for the hydrogen generation reaction. Tantalates, with tunable compositions, show high activities owning to their layered perovskite structure. (Oxy)nitrides, especially TaON and Ta3N5, have small band gaps to respond to visible-light, whereas they can still realize overall solar water splitting with the proper positions of conduction band minimum and valence band maximum. This review describes recent progress regarding the improvement of photocatalytic activities of tantalum-based semiconductors. Basic concepts and principles of solar water splitting will be discussed in the introduction section, followed by the three main categories regarding to the different types of tantalum-based semiconductors. In each category, synthetic methodologies, influencing factors on the photocatalytic activities, strategies to enhance the efficiencies of photocatalysts and morphology control of tantalum-based materials will be discussed in detail. Future directions to further explore the research area of tantalum-based semiconductors for solar water splitting are also discussed. © 2014 The Royal Society of Chemistry.


Xu C.,Tianjin University of Technology
2014 IEEE International Conference on Mechatronics and Automation, IEEE ICMA 2014 | Year: 2014

Grounding resistance is the main technical qualification of grounding system about Power plant and substation. We analyzed the feasibility of the method of measurement with short leads and discussed the current electrode lead length by comparing Common measurement methods of grounding resistance, a MATLAB software calculating program was compiled, and we calculated the position of measurement compensation point under the condition of uniform and vertical layered soil; The potential distribution of grounding grids was simulated under the uniform and vertical layered soil with ground simulation software CDEGS, the revised position of the result of measurement with short leads was compared with the real grounding resistance of grounding grids. Comparison results show that the rationality of the Measurement with short Leads method and the modifier formulas. © 2014 IEEE.


Mao Z.-Y.,CAS Shanghai Institute of Ceramics | Mao Z.-Y.,Tianjin University of Technology | Zhu Y.-C.,CAS Shanghai Institute of Ceramics | Gan L.,CAS Shanghai Institute of Ceramics | And 3 more authors.
Journal of Materials Chemistry | Year: 2012

White-light emission is realized through assembling a blue-emitting amorphous phase on a yellow-emitting Ca-SiAlON: Eu 2+ phosphor particle in the form of a coating. The variation of the yellowish-white-blue color is traced with the control of a blue-emitting coating formed via in situ penetration of silicon oxide into a Ca-SiAlON network. © The Royal Society of Chemistry 2011.


Li S.,Tianjin University of Technology | Gong J.,Tianjin University of Technology
Chemical Society Reviews | Year: 2014

Owing to the considerable publicity that has been given to petroleum related economic, environmental, and political problems, renewed attention has been focused on the development of highly efficient and stable catalytic materials for the production of chemical/fuel from renewable resources. Supported nickel nanoclusters are widely used for catalytic reforming reactions, which are key processes for generating synthetic gas and/or hydrogen. New challenges were brought out by the extension of feedstock from hydrocarbons to oxygenates derivable from biomass, which could minimize the environmental impact of carbonaceous fuels and allow a smooth transition from fossil fuels to a sustainable energy economy. This tutorial review describes the recent efforts made toward the development of nickel-based catalysts for the production of hydrogen from oxygenated hydrocarbons via steam reforming reactions. In general, three challenges facing the design of Ni catalysts should be addressed. Nickel nanoclusters are apt to sinter under catalytic reforming conditions of high temperatures and in the presence of steam. Severe carbon deposition could also be observed on the catalyst if the surface carbon species adsorbed on metal surface are not removed in time. Additionally, the production of hydrogen rich gas with a low concentration of CO is a challenge using nickel catalysts, which are not so active in the water gas shift reaction. Accordingly, three strategies were presented to address these challenges. First, the methodologies for the preparation of highly dispersed nickel catalysts with strong metal-support interaction were discussed. A second approach - the promotion in the mobility of the surface oxygen - is favored for the yield of desired products while promoting the removal of surface carbon deposition. Finally, the process intensification via the in situ absorption of CO2 could produce a hydrogen rich gas with low CO concentration. These approaches could also guide the design of other types of heterogeneous base-metal catalysts for high temperature processes including methanation, dry reforming, and hydrocarbon combustion. © 2014 the Partner Organisations.


Du X.,Tianjin University of Technology | Du X.,Tianjin Key Laboratory for Photoelectric Materials and Devices | Cai F.,Tianjin University of Technology | Wang X.,Tianjin University of Technology
Journal of Alloys and Compounds | Year: 2014

Bi2S3 is a promising thermoelectric material with low cost element of sulfur, but its ZT value is low because of the high electrical resistivity. In the present work, BiCl3 as donor dopant was added to Bi2S3 to improve the carrier content and reduce the electrical resistivity. The mechanical alloying (MA) and spark plasma sintering (SPS) techniques were used to prepare BiCl3 doped Bi 2S3 bulk samples. The optimizing carrier content tuned by dopant and the low thermal conductivity controlled by the fabrication process of MA and SPS resulted in the maximum ZT value 0.6 at 675 K for the Bi 2S3 bulk doped with 1.0 mol% BiCl3. © 2013 Elsevier B.V. All rights reserved.


Wang Z.,Tianjin University of Technology | Wang H.,Tianjin University of Technology | Liang M.,Tianjin University of Technology | Tan Y.,Tianjin University of Technology | And 3 more authors.
ACS Applied Materials and Interfaces | Year: 2014

Indoline photosensitizers exhibit impressive short-circuit photocurrent but generally low molar extinction coefficient and rapid charge recombination, which limits their application in thin-film dye-sensitizerd solar cells (DSCs). Here, we incorporate a new dithieno[3,2-b:2′,3′-d]pyrrole (DTP) segment (i.e., dihexyloxy-triphenylamine (DHO-TPA) substituted DTP) as the conjugated π-linker to construct a series of high molar absorption coefficient indoline dyes (XW69, XW70, and XW71) for DSCs employing a cobalt(II/III) redox electrolyte. Interestingly, this DTP linker is demonstrated as an efficient building block, not only slowing down the kinetics of charge recombination of titania electrons with tris(1,10-phenanthroline)cobalt(III) ions but also making a great contribution to the light absorption properties in comparison with the dihexylaniline substituted DTP. With respect to the dihexyloxy-triphenylamine dye (XW68), these new indoline dyes exhibit stronger light-harvesting and thus better power conversion efficiency of DSCs made from thin titania films. Benefitting from the bulky rigidity of the donor and π-conjugation unit, the XW70 dye displays a promising conversion efficiency as high as 8.78%, with a short-circuit current density (JSC) of 13.3 mA cm-2, open-circuit voltage (VOC) of 943 mV, and fill factor (FF) of 0.70 under AM 1.5 illumination (100 mW cm-2). Furthermore, the effect of light irradiation on these dyes adsorbed on nanocrystalline TiO2 films was investigated, proving the photostability of these indoline chromophores. Our work has valued the feasibility of judicious design of indoline chromophores to obtain organic photosensitizers for high-efficiency iodine-free DSCs made from thin titania films. © 2014 American Chemical Society.


Li Y.,Tianjin University of Technology | Su Y.,Tianjin University of Technology | Zhao X.,Tianjin University of Technology | He X.,Tianjin University of Technology | And 4 more authors.
ACS Applied Materials and Interfaces | Year: 2014

A facile method for fabricating antifouling and high-flux nanofiltration (NF) membranes was developed based on bioinspired polydopamine (PDA). Polyethersulfone (PES) ultrafiltration membrane as the support was first deposited a thin PDA layer and then chemically modified by a new kind of fluorinated polyamine via Michael addition reaction between fluorinated polyamine and quinone groups of PDA. PDA coating significantly reduced the pore sizes of the PES support membrane and endowed the NF membrane with high separation performance (flux about 46.1 L/(m2 h) under 0.1 MPa, molecular weight cutoff of about 780 Da). The grafted fluorinated polyamine on the PDA layer could form low free energy microdomains to impede the accumulation/coalescence of foulants and lower the adhesion force between foulants and the membrane, rendering the membrane surface with prominent fouling-release property. When foulant solutions (including bovine serum albumin, oil and humic acid) were filtered, the resultant NF membrane exhibited excellent antifouling properties (the minimal value of total flux decline ratio was ∼8.9%, and the flux recovery ratio reached 98.6%). It is also found that the structural stability of the NF membrane could be significantly enhanced due to the covalent bond and other intermolecular interactions between the PDA layer and the PES support. © 2014 American Chemical Society.


Sun X.,Tianjin University of Technology | Hao H.,Tianjin University of Technology | Ji H.,Tianjin University of Technology | Li X.,Tianjin University of Technology | And 2 more authors.
ACS Applied Materials and Interfaces | Year: 2014

Ordered mesoporous In2O3 gas-sensing materials with controlled mesostructured morphology and high thermal stability have been successfully synthesized via a nanocasting method in conjunction with the container effect. The mesostructured ordering, as well as the particle size, crystallinity and pore size distribution have been proved to vary in a large range by using the XRD, SAXRD, SEM, TEM, and nitrogen physisorption techniques. The control of the mesostructured morphology was carried out by tuning the transportation rate of indium precursor in template channel resulting from the different escape rate of the decomposed byproducts via the varied container opening and shapes. The particular relation between the mesostructured ordering and gas sensing property of mesoporous In2O3 was examined in detail. It was found that the ordered mesoporous In2O3 with appropriate mesostructured morphology exhibited significantly improved ethanol sensitivity, response and selectivity performances in comparison with the other ordered mesoporous In2O3, which benefits from the large surface area with enough sensing active sites, proper pore distribution for sufficient gas diffusion, and appropriate particle size for effective electron depletion. The resulting sensing behaviors lead to a better understanding of designing and using such mesoporous metal oxides for a number of gas-sensing applications. © 2013 American Chemical Society.


Chang J.,Tianjin University of Technology | Lu Y.,Tianjin University of Technology | He S.,Tianjin University of Technology | Liu C.,Tianjin University of Technology | And 3 more authors.
Chemical Communications | Year: 2013

A novel fluorometric sensing strategy based on the anion-induced rotation-displaced H-aggregates of styrylindolium dyes was employed to enhance the selectivity of fluorescent chemosensors for HSO4 - detection. The marvelous anion-induced H-aggregate strategy opens new routes to simple synthesis of receptors for tetrahedral anionic species. © 2013 The Royal Society of Chemistry.


Wang Z.,Tianjin University | Liang M.,Tianjin University of Technology | Wang L.,Tianjin University of Technology | Hao Y.,Tianjin University of Technology | And 3 more authors.
Chemical Communications | Year: 2013

Three dithieno[3,2-b:2′,3′-d]pyrrole (DTP) units with different hexyloxyphenyl (HOP) substituents have been developed for triphenylamine organic dyes (XS54-XS56). The introduction of the 4-HOP-DTP unit has resulted in a stronger light harvesting capacity, accounting for the observed photocurrent enhancement in the case of XS54, while the 2-HOP-DTP/2,4-HOP-DTP units induce a strikingly large photovoltage improvement in the cases of XS55 and XS56 due to their higher steric hindrance. © 2013 The Royal Society of Chemistry.


Zhang J.,Tianjin Polytechnic University | Shi Z.,Tianjin Polytechnic University | Wang C.,Tianjin University of Technology
Electrochimica Acta | Year: 2014

Lithium ion capacitors are assembled with pre-lithiated mesocarbon microbeads (LMCMB) anode and activated carbon (AC) cathode. The effect of pre-lithiation degrees on the crystal structure of MCMB electrode and the electrochemical capacitance behavior of LIC are investigated by X-ray diffraction (XRD) and the charge-discharge test of three-electrode cell. The structure of graphite still maintained when the pre-lithiation capacity is less than 200 mAh g-1, phase transition takes place with the increase of pre-lithiation capacity from 250 mAh g-1 to 350 mAh g-1. Pre-lithiation degrees of MCMB anode greatly affect the charge-discharge process and behavior, which impact on the electrochemical performance of LIC. The LIC with pre-lithiation capacity of 300 mAh g-1 has the optimal electrochemical performance. The energy density of LIC300 is up to 92.3 Wh kg-1, the power density as high as 5.5 kW kg-1 and the capacity retention is 97.0% after 1000 cycles. The excellent electrochemical performance benefits from the appropriate pre-lithiation capacity of negative electrode. The appropriate pre-lithiation ensures the working voltage of negative electrode in low and relative stable charge-discharge platform corresponding to the mutual phase transition from the second stage graphite intercalation compound (LiC12) to the first stage graphite intercalation compound (LiC6). The stable charge-discharge platform of negative electrode is conductive to the sufficient utilization of AC positive electrode. © 2014 Published by Elsevier Ltd.


Yang Y.,Tianjin University of Technology | Meng F.,Qufu Normal University
Mathematical Methods in the Applied Sciences | Year: 2013

This paper deals with the existence of positive solution for impulsive boundary value problem with p-Laplacian in Banach spaces. There is no literature researching on p-Laplacian boundary value problem in Banach spaces. The main difficulty that appears when passing from p = 2 to p ≠ 2 is that for p ≠ 2, it is impossible for us to find a Green's function in the equivalent integral operator because the differential operator (φp(u ′)) ′ is nonlinear, so it is difficult for us to prove that the equivalent integral operator is a strict-set-contraction operator. Even in the absence of pulse effect, these results are new. © 2012 John Wiley & Sons, Ltd.


Wang Z.,Northwestern Polytechnical University | Wang Z.,Kyushu University | Andrews M.A.,University of Guelph | Wu Z.-X.,Lanzhou University | And 2 more authors.
Physics of Life Reviews | Year: 2015

It is increasingly recognized that a key component of successful infection control efforts is understanding the complex, two-way interaction between disease dynamics and human behavioral and social dynamics. Human behavior such as contact precautions and social distancing clearly influence disease prevalence, but disease prevalence can in turn alter human behavior, forming a coupled, nonlinear system. Moreover, in many cases, the spatial structure of the population cannot be ignored, such that social and behavioral processes and/or transmission of infection must be represented with complex networks. Research on studying coupled disease-behavior dynamics in complex networks in particular is growing rapidly, and frequently makes use of analysis methods and concepts from statistical physics. Here, we review some of the growing literature in this area. We contrast network-based approaches to homogeneous-mixing approaches, point out how their predictions differ, and describe the rich and often surprising behavior of disease-behavior dynamics on complex networks, and compare them to processes in statistical physics. We discuss how these models can capture the dynamics that characterize many real-world scenarios, thereby suggesting ways that policy makers can better design effective prevention strategies. We also describe the growing sources of digital data that are facilitating research in this area. Finally, we suggest pitfalls which might be faced by researchers in the field, and we suggest several ways in which the field could move forward in the coming years. © 2015 Elsevier B.V..


Li L.,Tianjin University of Technology | Zhang A.,Tianjin University of Technology
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2011

The self-similar evolution of an initial Gaussian pulse propagating in a nonlinearity increasing fiber (NIF) with an exponential nonlinearity profile is studied theoretically and numerically. As well as the dispersion decreasing fiber with normal group velocity dispersion (ND-DDF with a hyperbolic dispersion profile), the NIF is also equivalent to a fiber amplifier, which can generate a parabolic self-similar pulse with strictly linear chirp. Furthermore, the impacts of two equivalent ways of ND-DDF and NIF on characteristics of the self-similar evolution are studied. The theoretical and simulation results show that: 1) the equivalent gain determines the results of self-similar evolution while the equivalent method determines the process speed; 2) with the same equivalent gain, the initial pulses in ND-DDF and NIF both evolve into the same parabolic self-similar pulse, but the process of NIF is more efficient, needing a shorter fiber length; 3) the relationship of fiber lengths of NIF and ND-DDF is to make the two fibers have the same "effective amplification".


Liu J.,Hebei University of Technology | Yuan J.,Hebei University of Technology | Xie L.,Tianjin University of Technology | Ji Z.,Hebei University of Technology
Energy | Year: 2013

Exergy analysis is a powerful tool for determining the efficiency of processes that influence system performance. Thus, the exergy of dual-stage NF (nanofiltration) seawater desalination was analyzed. Three different processes were simulated by Dow's Reverse Osmosis System Analysis, and the exergies were compared. The results indicated that the main exergy destruction in the conventional process occurred in the membrane and concentration stream valves. To reduce the exergy and energy consumption, concentration blending and an energy recovery device were applied in the improved process, which reduced the specific energy consumption and enhanced the exergetic efficiency and recovery ratio. The calculated specific energy consumption was reduced to 2.09kWh/m3, and the system recovery ratio was increased to reach 42.78% under the condition specified in this paper. Thus, the development of a novel energy-saving membrane module and an energy recovery device is important in reducing energy consumption in dual-stage NF seawater desalination. © 2013 Elsevier Ltd.


Zhang Y.-B.,Tianjin University of Technology | Yin J.,Tianjin University of Technology | Li L.,Tianjin University of Technology | Zhang L.-X.,Tianjin University of Technology | Bie L.-J.,Tianjin University of Technology
Sensors and Actuators, B: Chemical | Year: 2014

A facile approach for synthesis of flower-like p-CuO/n-ZnO heterojunction nanorods was reported. The CuO/ZnO nanorods were prepared by co-precipitation of CuO nanoparticles on the hydrothermally grown ZnO nanorods. The obtained samples were characterized by X-ray diffraction and transmission electron microscopy, which confirms that the heterogeneous nanostructure of the CuO/ZnO nanorods was highly crystalline. The ethanol gas-sensing properties of CuO/ZnO nanorods were evaluated with different ethanol vapor concentrations at the working temperature of 300 °C. The response of 0.25:1 CuO/ZnO nanorod sensor to 100 ppm ethanol was 98.8, which is 2.5 times that of ZnO only sample, with a response and recovery time of 7 s and 9 s, respectively. Good selectivity and long-term stability can also be achieved and the response of low concentration as 1 ppm ethanol can reach the value of 9.68 using the flower-like p-CuO/n-ZnO heterojunction nanorods as sensing material. The enhanced ethanol response is mainly attributed to a wider depletion layer on the CuO/ZnO surface resulted from the formation of p-n heterojunctions between p-CuO nanoparticles and n-type ZnO nanorods. © 2014 Elsevier B.V.


Lv L.,Tianjin University of Technology | Wang H.,Tianjin University of Technology
Materials Letters | Year: 2014

Silver sulfide (Ag2S) nanorice was synthesized by reaction between silver ammonia complex cation ([Ag(NH3)2] +) and sodium sulfide nonahydrate (Na2S·9H 2O) in the presence of polyvinylpyrrolidone (PVP) through a hydrothermal method. The obtained products were characterized by X-ray powder diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-vis) and transmission electron microscopy (TEM). It was found that the as-prepared Ag2S nanocrystal was monoclinic, and the formation of the rice-shaped feature depended mainly on the type of silver source, influence of the pyrrolidone rings of the PVP, reaction time and temperature. Both the remarkable blue shift and the large band gap energy of 4.4 eV revealed that the tip part of the as-prepared Ag2S nanorice could result in quantum confinement effect. © 2014 Elsevier B.V.


Qin S.,Tianjin University | Xin F.,Tianjin University | Liu Y.,Tianjin University | Yin X.,Tianjin University of Technology | Ma W.,Tianjin University of Technology
Journal of Colloid and Interface Science | Year: 2011

Photocatalytic reduction of CO2 on CuO-TiO2 composite catalysts in the presence of methanol to prepare methyl formate had been investigated. Methanol was used as sacrificial reagent to react with the photo-generated holes in the valence band, and CO2 was reduced by the electrons in the conduction band. CuO-TiO2 was optimized for CuO loading, preparation method and calcination temperature. The catalyst of 1.0CuO-TiO2, calcined at 450°C and CTAB as a dispersant showed the highest overall activity. The heterojunction between CuO and TiO2 demonstrated with HRTEM played an important role in enhancing the photocatalytic activity. © 2010 Elsevier Inc.


Li W.,Tianjin University of Technology | Shi S.,Tianjin University of Technology
Advanced Materials Research | Year: 2011

Because the traditional teaching resources management systems are limitations on the description and acquisition of distributed heterogeneous knowledge, domain ontology knowledge base of teaching resources management has been built with the help of experts in the field. A new algorithm of concept similarity has been proposed for calculating the distance between the words, and the ontology has been searched by using Jena API. Finally, the model of system has been implemented. Although the ontology storage method and execution efficiency should be improved, the system has got the initial achievement for the research of ontology in teaching resources management domain.


Lu Y.,Tianjin University of Technology | Wang M.T.,Tianjin University of Technology | Hao C.J.,Tianjin University of Technology | Zhao Z.Q.,Tianjin University of Technology | Yao J.Q.,Tianjin University of Technology
IEEE Photonics Journal | Year: 2014

A temperature sensor based on photonic crystal fiber (PCF) surface plasmon resonance (SPR) is proposed in this paper. We use the dual function of the PCF filled with different concentrations of analyte and silver nanowires to realize temperature sensing. The proposed sensor has been analyzed through numerical simulations and demonstrated by experiments. The results of the simulations and experiments show that a blue shift will be obtained with the temperature increase, and different concentrations will change the resonance wavelength and confinement loss. Temperature sensitivity is as high as 2.7 nm/°C with the experiment, which can provide a reference for the implementation and application of a PCF-based SPR temperature sensor or other PCF-based SPR sensing. © 2009-2012 IEEE.


Jin J.,Tianjin University of Technology | Shi Z.-Q.,Tianjin Polytechnic University | Wang C.-Y.,Tianjin University of Technology
Electrochimica Acta | Year: 2014

A series of hard carbon nanofiber-based electrodes derived from electrospun polyacrylonitrile (PAN) nanofibers (PAN-CNFs) have been fabricated by stabilization in air at about 280 °C and then carbonization in N2 at heat treatment temperatures (HTT) between 800 and 1500°C. The electrochemical performances of the binder-free, current collector-free carbon nanofiber-based anodes in lithium-ion batteries and sodium-ion batteries are systematically investigated and compared. We demonstrate the presence of similar alkali metal insertion mechanisms in both cases, but just the differences of the layer spacing and pore size available for lithium and sodium ion lead the discharge capacity delivered at sloping region and plateau region to vary from the kinds of alkali elements. Although the anodes in sodium-ion batteries show poorer rate capability than that in lithium-ion batteries, they still achieve a reversible sodium intercalation capacity of 275 mAh g-1 and similar cycling stability due to the conductive 3-D network, weakly ordered turbostratic structure and a large interlayer spacing between graphene sheets. The feature of high capacity and stable cycling performance makes PAN-CNFs to be promising candidates as electrodes in rechargeable sodium-ion batteries and lithium-ion batteries. © 2014 Elsevier Ltd.


Liu T.,Tianjin University | Liu T.,Tianjin University of Technology | Chen Y.,Tianjin University | Han Q.,Tianjin University | Lu X.,Tianjin University
IEEE Photonics Journal | Year: 2014

In this paper, an all-fiber magnetic field sensor based on a U-bent single-mode fiber and magnetic fluid (MF) is proposed and investigated. Because of the tunable refractive index and absorption coefficient of MF, the transmission spectrum will change with the magnetic field strength (H), which can be used to demodulate H through the wavelength shift or the intensity change. The influence of the diameter of the U shape to the performance of the sensor is investigated and discussed. In the experiments, the highest sensitivities achieved with wavelength and intensity demodulation are 0.374 nm/Oe and -0.4821 dB/Oe, respectively. The reproducibility of the sensor is studied as well. © 2009-2012 IEEE.


Zhang D.,Tianjin University of Technology | Kang X.,Tianjin University of Technology | Wang J.,Tianjin University of Technology
Eurasip Journal on Advances in Signal Processing | Year: 2012

In this article, a novel image de-noising method is proposed. This method is based on spherical coordinates system. First, spherical transform is re-defined in wavelet domain, and the properties of the spherical transform in wavelet domain are listed. Then, a new adaptive threshold in spherical coordinate system is presented. It has been proved based on Besov space norm theory. After that, a novel curve shrinkage function is proposed to overcome the limitation of the traditional shrinkage functions. The new function can reach and exceed the true value and enhance the edge of the image. Finally, the multi-scale product in wavelet domain is introduced to spherical coordinates system. This article names the multi-scale product in spherical coordinates system as Multi-Scale Norm Product. The experimental results compared the improved algorithm with other methods from the peak signal-tonoise ratio, mean square error, and running time. The results indicate that improved algorithm is simple and effective. © 2012 Zhang et al.


Ye X.,Tianjin University of Technology | Chen M.,Tianjin University of Technology | Chen M.,Tianjin Key Laboratory for Photoelectric Materials and Devices | Yang M.,Tianjin University of Technology | And 2 more authors.
Journal of Materials Science: Materials in Medicine | Year: 2010

Due to good biocompatibility and mechanical properties, magnesium (Mg) and its alloys are considered promising degradable materials for orthopedic applications. In this work, a Mg metal matrix composite (MMC) was fabricated using Mg-2.9Zn-0.7Zr alloy as the matrix and 1 wt% nano-hydroxyapatite (n-HA) particles as reinforcements. In vitro corrosion behavior and cytocompatibility of a Mg-Zn-Zr/n-HA composite and a Mg-Zn-Zr alloy were investigated. In contrast with the Mg-Zn-Zr alloy, the MMC has better properties. The average corrosion rate of MMC is 0.75 mm/yr after immersion in simulated body fluid (SBF) for 20 days, and the surface of MMC is covered with white Ca-P precipitates. The electrochemical test results show that the corrosion potential (E corr) of MMC increases to -1.615 V and its polarization resistance (R p) is 2.56 KΩ with the addition of n-HA particles. The co-cultivation of MMC with osteoblasts results in the adhesion and proliferation of cells on the surface of the composite. The maximum cell density is calculated to be (1.85±0.15) × 104/l after 5 days of co-culture with osteoblasts. The average cell numbers for two groups after culturing for 3 and 5 days (P<0.05) are significantly different. All the results demonstrate that the Mg-Zn-Zr/n-HA composite can be potentially used as biodegradable bone fixation material. © 2009 Springer Science+Business Media, LLC.


Wang H.,Tianjin University of Technology | Wang L.,Tianjin University of Technology
Journal of Information and Computational Science | Year: 2013

Fuzzy Cognitive Map (FCM) is ideal causal knowledge acquiring tool and models the causal system as a collection of concepts and causal relationships among concepts. Aiming at the problem of the high false positive rate in the current intrusion detection system, this paper presents an improved FCM combined Ordered Weighted Averaging (OWA) operators and fuzzy neural network. The experiment results show that this approach can effectively reduce false positive rate and has a high detection rate. © 2013 by Binary Information Press.


Elleuch A.,University of Sfax | Yu J.,Tianjin University of Technology | Boussetta A.,University of Sfax | Halouani K.,University of Sfax | Li Y.,Tianjin University of Technology
International Journal of Hydrogen Energy | Year: 2013

As a promising intermediate temperature fuel cell, Direct Carbon Fuel Cell (DCFC) with composite electrolyte composed of Samarium-Doped Ceria (SDC) and a binary carbonate phase (67 mol% Li2CO3/33 mol% Na 2CO3) has a much higher efficiency compared with conventional power suppliers. In the present work, SDC powder has been synthesized by an oxalate co-precipitation process and used as solid support matrix for the composite electrolyte. Single cell with composite electrolyte layer is fabricated by a dry-pressing technique using LiNiO2/Li 2Na2CO3/SDC as cathode and 1:9 (weight ratio) graphite mixture with 67 mol% Li2CO3/33 mol% Na 2CO3 molten carbonate as anode. The cell is tested at 600-750 C using electrolytical graphite mixture as fuel and O 2/CO2 mixture as oxidant. A relatively good performance with high power density of 58 mW cm-2 at 700 C is achieved for a DCFC using 0.8 mm thick composite electrolyte layer. The sensibility of the 1 cm2 DCFC single cell performance to the anode gas nature is also investigated. At temperatures higher than 700 C, both carbon (C) and carbon monoxide (CO) can be considered as reacting fuel for the DCFC system. © Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Zhang D.-G.,Tianjin University of Technology | Dai W.-B.,Tianjin University of Technology | Niu Q.-X.,Tianjin University of Technology
Tien Tzu Hsueh Pao/Acta Electronica Sinica | Year: 2012

Many real networks included Wireless Sensor Networks (WSN) can be considered as scale-free weighted networks which reflect their existing forms and dynamic characteristics. Based on local-world theory, we propose an uneven clustering weighted evolving model of WSN in this paper. The definitions of edge weight and vertex strength take sensor energy, communication traffic and distance into consideration. Vertex strength drives the growth of topology and edge weight dynamically changes correspondingly. Experimental results demonstrate that WSN topology we obtain has the property of weighted networks: edge weight, vertex degree and strength follow a power law distribution. Related research work show that weighted WSN not only share the robustness and fault tolerance of weight-free networks, but also reduce the happening probability of successive node-breakdown, furthermore, enhance the synchronization of WSN.


Zhu Z.,Tianjin University of Technology | Kao C.-T.,Providence University | Wu R.-J.,Providence University
Applied Surface Science | Year: 2014

In this study, the ethanol-sensing characteristics of Ag@TiO2 nanoparticles were investigated. The morphology, structure, and formation mechanism of the Ag@TiO2 core-shell nanoparticles were carefully studied using X-ray diffraction, transmission electron microscopy, ultraviolet-visible spectroscopy, ZetaSizer Nano ZS and energy-dispersive X-ray spectroscopy. A gas sensing study showed that Ag@TiO2 is a promising sensor for detecting ethanol gas at low concentrations (below 5 ppm) at room working temperature. Ag@TiO2 exhibited a sensor response of 1.04-4.35 at the ethanol concentration from 0.15 ppm to 5 ppm. In addition, the sensor presented an excellent selectivity and stability for ethanol gas. This systematic study of the promising ethanol-sensing characteristics of Ag@TiO2 nanoparticles can facilitate the development of sensors that detect ethanol gas. © 2014 Elsevier B.V. All rights reserved.


E X.-T.-F.,Tianjin University of Technology | Zhang Y.,Tianjin University of Technology | Zou J.-J.,Tianjin University of Technology | Zhang X.,Tianjin University of Technology | Wang L.,Tianjin University of Technology
Materials Letters | Year: 2014

The shape evolution and control in the Brust-Schiffrin synthesis of Au nanoparticles (NPs) is presented in this work. Different from the current wisdom, Au NPs undergoes a time-dependent shape evolution. At the beginning, small spherical NPs are produced as reported before. With prolonged time, however, big NPs with many thermodynamically unfavored shapes such as triangle and truncated triangle are formed. And they are ultimately transferred into spherical shape bigger than the original NPs. It is suggested that the shape evolution is a kinetic-to-thermodynamic control process, during which, well-defined triangular plates are produced considerably by tuning the types of protecting ligands. This reveals the potential of fabricating not only size but also shape controllable metal NPs using the popular Brust-Schiffrin synthesis. © 2013 Elsevier B.V.


Chen W.,Henan University | Tong H.,Henan University | Liu H.,Tianjin University of Technology
Marine Pollution Bulletin | Year: 2012

The aim of this study was to investigate the effect of nitrate on nitrite toxicity to Microcystis aeruginosa. Short-term uptake experiment revealed nitrate could depress the nitrite active uptake. The long-term experiment of nitrate effects on nitrite toxicity showed a negative relationship between the growth and intracellular nitrite levels of M. aeruginosa. The net nitrite uptake displayed a decline in the range of 0-150. mg NO3--NL-1 and an elevation at 200. mg NO3--NL-1, whereas the activities of nitrate reductase (NR) were more sensitive to nitrate than nitrite reductase (NiR). As a result, the total intracellular nitrite levels tended to decrease up to 100. mg NO3--NL-1 then increased at 150-200. mg NO3--NL-1. These results suggested the existence of external nitrate could affect the toxicity of nitrite to alga through changing intracellular nitrite content. © 2012 Elsevier Ltd.


Huang P.,Tianjin University of Technology | Jiang H.,Tianjin University of Technology | Zhang M.,Tianjin University of Technology
Journal of Rare Earths | Year: 2012

CeO 2-ZrO 2-Al 2O 3 ternary oxides were successfully prepared by a green route of supercritical anti-solvent precipitation with supercritical CO 2 as anti-solvent and methanol as solvent. The structures and oxygen storage capacities of these ternary oxides were characterized by XRD, Raman spectra and oxygen storage capacity measurements. It was found that Al 3+ and Zr 4+ inserted into CeO 2 lattice, forming CeO 2-ZrO 2-Al 2O 3 solid solution. The concentration of aluminium isopropoxide in the solution affected the concentration of oxygen vacancy and the distortion of oxygen sublattice which were responsible for the oxygen storage capacity. The rapidest oxygen uptake/release rate and maximum total oxygen storage capacity (122.0 mmolO 2/molCeO 2) were obtained with the aluminium isopropoxide concentration at 0.2 wt. in the solution. © 2012 The Chinese Society of Rare Earths.


Liu B.,Tianjin University of Technology | Wang T.,Transportation Institute
Zidonghua Xuebao/Acta Automatica Sinica | Year: 2012

Convex hull is one of the basic structures in computational geometry, which is used in many fields of computer graphics and image. A novel algorithm of convex hull is proposed. Principle component analysis (PCA) is used to do the pretreatment on the planar point set. The applicable sort regulation and determinant principle of edge points in convex hull are studied. The new algorithm is applied to a fast 3D measurement system based on digital fringe projection to extract the minimal convex hull formed by the intensive residual points in the phase interferogram. The system can avoid the phase unwrapping error caused by the residual points by masking the area of the extracted convex hull to guarantee the accuracy of three-dimensional shape reconstruction. Experimental results prove that the presented algorithm not only has high reliability, but also gets better operational efficiency. Copyright © 2012 Acta Automatica Sinica. All rights reserved.


Xie X.,Tianjin University of Technology | Zhang C.,Tianjin University of Technology | Wu M.-B.,China University of Petroleum - East China | Tao Y.,Tianjin University of Technology | And 4 more authors.
Chemical Communications | Year: 2013

Graphene oxide hydrogel is used as a reactive template to prepare nanoporous materials with a 3D microstructure. The as-prepared porous MnO 2 shows a capacitance retention of ∼70.6% at a current density as high as 15 A g-1, resulting from the 3D interconnected ion transport channel replicated from the graphene oxide hydrogel. © 2013 The Royal Society of Chemistry.


Zhao H.,Nankai University | Meng X.,Nankai University | Meng X.,Tianjin University of Technology | Huang Y.,Nankai University
Chemical Communications | Year: 2013

PPh3-Catalyzed aza-MBH domino reaction of salicyl N-tosylimines with γ-CH3 substituted allenoates is reported. Readily available imines and allenoates are converted to benzoxazepine derivatives in one step. Wherein, functionalization of C-H bonds of γ-substituted allenoate has been developed in this domino process. © 2013 The Royal Society of Chemistry.


Zhao J.Y.,Tianjin University of Technology | Guo H.M.,China University of Geosciences
Advanced Materials Research | Year: 2013

Arsenic concentration changes in small-scale simulating constructed wetland composed with shale ceramic, zeolite, quartz sand and Pteris vittata were examined. During arsenic removal by the constructed wetlands, arsenic interception by the natural media played the main role in the early stage and Pteris vittata uptake played the key role for arsenic removal in the later stable stage. When As (III) concentration in inflow was about 1 mg/L, the arsenic removal ratio by the two was between 22.2% and 66.6% and kept about 33% in the end. Arsenic average content in fronds and roots of Pteris vittata after experiments were respectively 17610 and 2491 mg/kg. Transfer factor was 7.08. Compared with batch tests, arsenic content accumulated in plants increased significantly. © (2013) Trans Tech Publications, Switzerland.


Zhao N.,Tianjin University of Technology
Nature Photonics | Year: 2015

Increasing the information capacity per unit bandwidth has been a perennial goal of scientists and engineers. Multiplexing of independent degrees of freedom, such as wavelength, polarization and more recently space, has been a preferred method to increase capacity in both radiofrequency and optical communication. Orbital angular momentum, a physical property of electromagnetic waves discovered recently, has been proposed as a new degree of freedom for multiplexing to achieve capacity beyond conventional multiplexing techniques, and has generated widespread and significant interest in the scientific community. However, the capacity of orbital angular momentum multiplexing has not been established or compared to other multiplexing techniques. Here, we show that orbital angular momentum multiplexing is not an optimal technique for realizing the capacity limits of a free-space communication channel and is outperformed by both conventional line-of-sight multi-input multi-output transmission and spatial-mode multiplexing. © 2015 Nature Publishing Group


Wu H.,Tianjin University of Technology
Journal of Forestry Research | Year: 2015

Platycladus orientalis is one of the most popular afforestation species and greening species for water management in arid and semi-arid regions of northern China. We applied various models to estimate and validate artificial P. orientalis forest evapotranspiration features with the goal of accurately estimating the water use of a P. orientalis plantation. The American Society of Civil Engineers Evapotranspiration–Penman–Monteith model (APM) and FAO56–Penman–Monteith model (FPM) are extensively applied for vegetation evapotranspiration estimation because their reliability has been validated by many scholars. The Priestley–Taylor model (PT) and Hargreaves model (HS) require only the daily maximum temperature, daily minimum temperature and solar radiation to estimate evapotranspiration and are thus widely applied to grasslands but not to forests. We used the Energy Balance Bowen Ratio (EBBR) system to validate the accuracy of the four models. The results indicated that: (1) Compared to the EBBR measurement annual value, APM was the most accurate, followed by FPM, and PT; (2) During the year, the accuracies of the four models varied. APM and FPM underestimated evapotranspiration during June, July and August, whereas PT and HS overestimated evapotranspiration during this period. In the rest of the year, the estimation accuracies were reversed; (3) An analysis of the possible reasons indicated that wind speed, air temperature and precipitation were the most important contributors. High temperatures were measured in June, July and August, which led to an overestimation by PT and HS because these two models only calculated the temperature and radiation without vegetation information. Underestimation also occurred when a low temperature was recorded. Though APM and FPM addressed both meteorological and vegetation factors, slight deviations still existed; and (4) The two models were modified based on EBBR-measured data. Relative humidity was introduced into PT, and parameter “A” in the HS estimation model was amended to 1.41. The accuracy of the modified models significantly increased. The study highlighted the application, comparison and improvement of four models in estimating evapotranspiration and offers more approaches to assess forest hydrological functions. © 2015 Northeast Forestry University and Springer-Verlag Berlin Heidelberg


Cai S.,Tianjin University of Technology | Lu Y.,Tianjin University of Technology | He S.,Tianjin University of Technology | Wei F.,Tianjin University of Technology | And 3 more authors.
Chemical Communications | Year: 2013

A fluorescent chemosensor with high sensitivity and selectivity for palladium species based on a conjugate of phosphine and rhodamine B has been developed. The chemosensor showed an excellent palladium selectivity with a detection limit down to the 10-9 M range, which is lower than the WHO limit for palladium content in drug chemicals. © 2013 The Royal Society of Chemistry.


Li S.,Tianjin University of Technology | Zhang C.,Tianjin University of Technology | Huang Z.,Tianjin University of Technology | Wu G.,Tianjin University of Technology | Gong J.,Tianjin University of Technology
Chemical Communications | Year: 2013

This communication describes the synthesis of a nanocomposite Ni@ZrO 2 catalyst with enhanced metal-support interaction by introducing metal nanoparticles into the framework of the oxide support. The catalyst shows high catalytic activity and stability for hydrogen production via steam reforming of ethanol. © 2013 The Royal Society of Chemistry.


Chu J.,Tianjin University of Technology | Jin Z.,Tianjin University of Technology | Yang J.,Zhejiang University | Hong Z.,Zhejiang University
Journal of the American Ceramic Society | Year: 2012

In this work, an in situ chemical reaction deposition technique using solid cadmium precursor films as reaction source and ammonium sulfide-based solutions as anionic reaction medium was presented to deposit uniform, crack-free, densely packed nano-crystalline, hexagonal wurzite structure Cadmium sulfide (CdS) thin films. Influence of the Cd:S molar concentrations in separate cationic and anionic precursor solutions, deposition cycle numbers, and annealing treatment in Ar atmosphere on structure, morphology, film growth, chemical composition, and optical properties of the in situ chemical deposited films are investigated based on XRD, FESEM, AFM, HRTEM, EDS, SAED, and UV-Vis measurements. © 2012 The American Ceramic Society.


Zhang L.,Tianjin University of Technology | Xie Z.,Xiamen University | Gong J.,Tianjin University of Technology
Chemical Society Reviews | Year: 2016

Au-Pd nanostructured materials have been recognized as important heterogeneous catalysts in various reactions, due to their superior activities caused by the ensemble and ligand effects. In recent years, shape-controlled synthesis of noble metal nanocrystals (NCs) provided a brand-new insight for improving the performance of catalysts. The electronic properties and catalytic activities of Au-Pd NCs could be optimized by tuning their shape and composition engineering. This review describes recent progress in the design and synthesis of shape-controlled Au-Pd bimetallic NCs and their emerging catalytic applications. The review starts with a general discussion of various applications of Au-Pd catalysts and the significance of preparing shape-controlled Au-Pd NCs, followed by an overview of synthetic strategies for two different structures of Au-Pd bimetallic catalysts: a core-shell structure and an alloy structure. We also put forward the key factors for the preparation of Au-Pd core-shell and alloy structures. Additionally, we discussed the unique optical properties and structural effects of shape-controlled Au-Pd NCs. These recent advancements in the methodology development of Au-Pd bimetallic NCs offer numerous insights for generating Au-Pd NCs with a number of unique geometries in the future. Furthermore, the systematic synthesis of core-shell or alloy structures would provide insights for the preparation of other bimetallic NCs. © 2016 The Royal Society of Chemistry.


Ding S.,Hefei University of Technology | Ding S.,Key Laboratory of Process Optimization and Intelligent Decision Making | Yang S.,Hefei University of Technology | Yang S.,Key Laboratory of Process Optimization and Intelligent Decision Making | And 4 more authors.
Knowledge-Based Systems | Year: 2014

The collection and combination of assessment data in trustworthiness evaluation of cloud service is challenging, notably because QoS value may be missing in offline evaluation situation due to the time-consuming and costly cloud service invocation. Considering the fact that many trustworthiness evaluation problems require not only objective measurement but also subjective perception, this paper designs a novel framework named CSTrust for conducting cloud service trustworthiness evaluation by combining QoS prediction and customer satisfaction estimation. The proposed framework considers how to improve the accuracy of QoS value prediction on quantitative trustworthy attributes, as well as how to estimate the customer satisfaction of target cloud service by taking advantages of the perception ratings on qualitative attributes. The proposed methods are validated through simulations, demonstrating that CSTrust can effectively predict assessment data and release evaluation results of trustworthiness. © 2013 Elsevier B.V. All rights reserved.


Zhang P.,Tianjin University of Technology | Zhang P.,University of Maryland University College | He J.,University of Maryland University College | Ma X.,Tianjin University of Technology | And 2 more authors.
Chemical Communications | Year: 2013

This communication describes a facile method for the synthesis of conical-shaped Au nanoparticles with a hollow cavity by combining interfacial reaction and ultrasonic cavitation. The Au nanocones showed an enhancement factor of 7.7 × 108 in surface enhanced Raman scattering (SERS) detection. © The Royal Society of Chemistry 2013.


Han S.-D.,Nankai University | Song W.-C.,Nankai University | Zhao J.-P.,Nankai University | Zhao J.-P.,Tianjin University of Technology | And 4 more authors.
Chemical Communications | Year: 2013

An unprecedented polynuclear cobalt complex with a [Co24] macrocycle in the presence of [Co(H2O)6]2+ has been prepared and characterized. In this complex, [Co(H2O) 6]2+ not only acts as a counterion to balance the negative charge of the 2D layer, but may also serve as a template in the assembly of the [Co24] macrocyclic complex through hydrogen-bond interactions. Magnetic analyses indicate that the title compound shows homometallic ferrimagnetic behavior. © The Royal Society of Chemistry 2013.


Luan N.,Tianjin University | Luan N.,Tianjin University of Technology | Wang R.,Tianjin University | Wang R.,Tianjin University of Technology | And 5 more authors.
Optics Express | Year: 2015

To solve the phase matching and analyte filling problems in the microstructured optical fiber (MOF)-based surface plasmon resonance (SPR) sensors, we present the D-shaped hollow core MOF-based SPR sensor. The air hole in the fiber core can lower the refractive index of a Gaussian-like core mode to match with that of a plasmon mode. The analyte is deposited directly onto the D-shaped flat surface instead of filling the fiber holes. We numerically investigate the effect of the air hole in the core on the SPR sensing performance, and identify the sensor sensitivity on wavelength, amplitude and phase. This work allows us to determine the feasibility of using the D-shaped hollow-core MOFs to develop a high-sensitivity, real-time and distributed SPR sensor. © 2015 Optical Society of America.


Liu A.-H.,Tianjin University of Technology | Yang L.-Y.,Tianjin University of Technology | Yang L.-Y.,Tianjin Key Laboratory for Photoelectric Materials and Devices
Faguang Xuebao/Chinese Journal of Luminescence | Year: 2012

A double layer NPB/Alq 3 heterojunction organic light emitting device using Ag/4-FTP(SAM)/m-MTDATA as combined hole-injecting layer was fabricated. The device performance was studied and compared with the control device. The effect of the Ag layer thickness on the device performance is also investigated. The variation of the spectral narrowing and intensity enhancement can be explained with microcavity effects. The results revealed that indium tin oxide (ITO) anode modified with Ag(5 nm)/ 4-FTP(SAM) demonstrated good transparency, enhanced hole injection ability and smooth interface morphology, which result in an improved device performance. The highest luminance of 34680 cd/m 2 at 12 V and a luminous efficiency of 6.9 cd/A were achieved for the device with the structure of ITO/Ag/4-FTP(SAM)/m-MTDATA/NPB/Alq 3/LiF/Al. However, the control device showed 25300 cd/m 2 at the same bias.


Yu D.,Nanyang Technological University | Wei L.,Nanyang Technological University | Jiang W.,Nanyang Technological University | Wang H.,Nanyang Technological University | And 5 more authors.
Nanoscale | Year: 2013

Electrocatalysts for anode or cathode reactions are at the heart of electrochemical energy conversion and storage devices. Molecular design of carbon based nanomaterials may create the next generation electrochemical catalysts for broad applications. Herein, we present the synthesis of a three-dimensional (3D) nanostructure with a large surface area (784 m 2 g-1) composed of nitrogen doped (up to 8.6 at.%) holey graphene. The holey structure of graphene sheets (∼25% of surface area is attributed to pores) engenders more exposed catalytic active edge sites. Nitrogen doping further improves catalytic activity, while the formation of the 3D porous nanostructure significantly reduces graphene nanosheet stacking and facilitates the diffusion of reactants/electrolytes. The three factors work together, leading to superb electrochemical catalytic activities for both hydrazine oxidation (its current generation ability is comparable to that of 10 wt% Pt-C catalyst) and oxygen reduction (its limiting current is comparable to that of 20 wt% Pt-C catalyst) with four-electron transfer processes and excellent durability. © The Royal Society of Chemistry 2013.


Wang Y.,Tianjin University of Technology | Ren W.,Tianjin University of Technology | Wang H.,Tianjin University of Technology
Computers and Mathematics with Applications | Year: 2013

This paper proposes novel second order and fourth order anisotropic diffusion models for image denoising. These two models are based on CONvolutional Virtual Electric Field (CONVEF). The proposed second order anisotropic diffusion model was introduced by introducing the CONVEF into the Perona-Malik (P-M) equation and the fourth order one is coined by combining CONVEF and the You-Kaveh (Y-K) equation. The employment of the CONVEF model allows to improve the estimation of high order derivatives and makes the proposed methods more robust to noise. In addition, the proposed CONVEF-based Y-K model is an anisotropic diffusion equation which can avoid the over-smoothness of edges and provide better edge protection capability except for better denoising. Some experiments are conducted to demonstrate the efficiency of the proposed methods. © 2013 Elsevier Ltd. All rights reserved.


Xitao W.,Tianjin University of Technology | Rong L.,Tianjin University of Technology | Kang W.,Tianjin University of Technology
Journal of Materials Chemistry A | Year: 2014

ZnO@ZnS-Bi2S3 core-shell nanorods anchored on reduced graphene oxide (RGO) were prepared by combining the hydrothermal treatment and ion exchange technique. The nanocomposites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction, Raman, X-ray photoelectron spectroscopy (XPS), UV-Vis diffusion reflectance spectroscopy, room-temperature photoluminescence spectra (PL), and their photocatalytic performance for H2 evolution under 300 W Xenon lamp irradiation was evaluated. The as-prepared RGO/ZnO@ZnS-Bi2S 3 core-shell nanorods display a wide and strong photo absorption in the visible region and exhibit a higher photocatalytic activity for H 2 evolution from the glycerol water mixtures as compared with the RGO/ZnO nanorods and RGO/ZnO@ZnS core-shell nanorods. Under the optimal Bi 2S3/ZnS molar ratio in the shell layer, the highest photocatalytic hydrogen production rate of 310 μmol h-1 g -1 is observed. The highly improved performance of the composites can be ascribed to the increased light absorption and efficient charge separation. © 2014 the Partner Organisations.


Wang S.,Tianjin University of Technology | Li C.,Tianjin University of Technology | Wang T.,Tianjin University of Technology | Zhang P.,Tianjin University of Technology | And 2 more authors.
Journal of Materials Chemistry A | Year: 2014

This paper describes a facile and generally feasible method to synthesize nanotube-type graphitic carbon nitride (g-C3N4) by directly heating melamine packed in an appropriate compact degree which plays a crucial role in the formation process of g-C3N4. This approach has several advantages: (i) no templates or extra organics are involved; (ii) high industrial feasibility; (iii) low cost; and (iv) general applicability. The as-synthesized g-C3N4 samples show intense fluorescence with a photoluminescent (PL) peak at 460 nm indicating their potential applications as a blue light fluorescence material. They also exhibit excellent visible-light photocatalytic activity compared to a reference P25 photocatalyst. The method reported may open up new opportunities for further studies as well as practical applications of g-C3N4 nanotubes in fields such as light-emitting devices, gas storage and photocatalysis. © 2014 The Royal Society of Chemistry.


Guo X.,Tianjin University of Technology | Liu N.,Tianjin University of Technology | Li X.,Tianjin University of Technology | Ou Z.Y.,Indiana University – Purdue University Indianapolis
Optics Express | Year: 2015

Mode matching plays an important role in measuring the continuous variable entanglement. For the signal and idler twin beams generated by a pulse pumped fiber optical parametric amplifier (FOPA), the spatial mode matching is automatically achieved in single mode fiber, but the temporal mode property is complicated because it is highly sensitive to the dispersion and the gain of the FOPA. We study the temporal mode structure and derive the input-output relation for each temporal mode of signal and idler beams after decomposing the joint spectral function of twin beams with the singular-value decomposition method. We analyze the measurement of the quadrature-Amplitude entanglement, and find mode matching between the multi-mode twin beams and the local oscillators of homodyne detection systems is crucial to achieve a high degree of entanglement. The results show that the noise contributed by the temporal modes nonorthogonal to local oscillator may be much larger than the vacuum noise, so the mode mis-match can not be accounted for by merely introducing an effective loss. Our study will be useful for developing a source of high quality continuous variable entanglement by using the FOPA. © 2015 Optical Society of America.


Pan Y.,CAS Research Center for Eco Environmental Sciences | Shi Y.,CAS Research Center for Eco Environmental Sciences | Wang J.,CAS Research Center for Eco Environmental Sciences | Jin X.,Tianjin University of Technology | Cai Y.,CAS Research Center for Eco Environmental Sciences
Bulletin of Environmental Contamination and Toxicology | Year: 2011

Detectable PFCs could be found in all samples. Perfluorooctanoic acid (PFOA) was the major PFC in river water, while perfluorooctane sulfonate (PFOS) was dominant in sediment and were 17- to 153-fold higher than those in water. PFCs concentrations in soil were little higher than those in sediment. In fish muscles PFOS showed the highest concentrations. Generally, PFC concentrations in fish were in the following rank order: crucian carp > silver carp> common carp. We suggested that there may be constant and diffuse pollution sources in Tianjin. Point sources also appeared to make significant contribution in the present study. © 2011 Springer Science+Business Media, LLC.


Xiao S.,University of Macau | Li Y.,Tianjin University of Technology
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

Smart material actuators like Piezoelectric(PZT) are widely used in Micro/Nano manipulators, but their hysteresis behaviors are complex and difficult to model. Most hysteresis models are based on elementary quasistatic operators and are not suitable for modeling rate-dependent or thermal-drift behaviors of the actuators. This work proposes a Preisach model based neurodynamic optimization model to account for the complex hysteresis behaviors of the smart material actuator system. Through simulation study, the rate-dependent and the thermal-drift behaviors are simulated via Bouc-Wen model. The μ-density function of the Preisach model is identified on-line through neurodynamic optimization method to suit for the varied rate of the input signals. The output of the actuator system is predicated in realtime based on the on-line identified μ-density plane. It is shown experimentally that the predicated hysteresis loops match the simulated PZT loops very well. © 2012 Springer-Verlag.


Li B.-Z.,Tianjin University of Technology
Applied Mechanics and Materials | Year: 2014

In this paper, we focused on the measurement and demonstration of technology innovation spillovers effects between sections. The forward R&D flux coefficient matrix model and backward R&D flux coefficient matrix model are established based on the input-output model, and then the beneficiary's effects and contributor's effects of ten leading industries within the Tangshan City are calculated. In the end, we found that the oil and natural gas industry got the highest score. The result can be used to make better suggestions for management of Tangshan regional innovation system. © (2014) Trans Tech Publications, Switzerland.


Li T.,Tianjin University of Technology
Lecture Notes in Electrical Engineering | Year: 2012

With the increase of life quality of our people, and with the new medical reform stepping onto the quick track, medical instrument industry is developing rapidly. The domestic portable medical electronic products are facing competition from both domestic and overseas. As the new listed company in the A stock market SME board, Jiuan Medical needs to conscientiously analyze its own strengths, weakness, environmental opportunities, and external threads (SWOT), nicely design its positioning in the market, and correctly set up marketing scheme, in order to win in the market with fierce competition. This paper made SWOT analysis for Jiuan portable medical electronic products on the basis of analyzing market environment of domestic portable medical electronic products, finding solutions of SWOT strategy and tactics. © Springer-Verlag 2012.


Li T.,Tianjin University of Technology | Chen L.,Tianjin University of Technology
Lecture Notes in Electrical Engineering | Year: 2012

"Internet of things" (IOT) is a very new concept created and developed in recent years. It had not been paid front attention until one or two years ago, when Chinese and US leaders announced emphasis on the development of IOT. To recover global economy under the economic and monetary crisis background, innovative technologies such as IOT are critical to create new economic development growth points. This paper first introduces the concept and origin of IOT, men describes basic principles of IOT, next illustrates the framework of IOT, and finally takes two examples to suggest applications of IOT. The paper intends to help readers recognize IOT as a whole, to hold the clue and venation of the development of IOT, and to forecast future trends of IOT development. © Springer-Verlag Berlin Heidelberg 2012.


Li H.,Tianjin University of Technology | Tian Y.,Tianjin University of Technology | Wang Z.,Tianjin University of Technology | Qie F.,Tianjin University of Technology | Li Y.,Tianjin University of Technology
RSC Advances | Year: 2012

A chemically stable perovskite material Sr 2Fe 1.5Mo 0.5O 6 (SFMO) is employed as the anode of a solid oxide fuel cell (SOFC). An electrolyte-supported single cell with anode, electrolyte and cathode all made of perovskite structured materials and with a configuration of SFMOLa 0.8Sr 0.2Ga 0.83Mg 0.17O 3Ba 0.5Sr 0.5Co 0.8Fe 0.2O 3 (SFMLSGMBSCF) is fabricated by a screen printing method. The single cell gives a maximum power density of 391 mW cm -2 for CH 3OH, and 520 mW cm -2 for H 2 as the fuel, respectively, at 1073 K with oxygen as the oxidant gas. The mass spectra of the flue gas out of the test reactor confirm that methanol thermally decomposes inside the anode chamber and generates mainly CO and H 2 at 1023 K. Analysis of the after-test cell tells that the anode surface has no carbon formation under reaction with methanol as the feed for 3 h. The carbon resistance is attributed to the fact that the anode is in oxide state which cannot facilitate the formation of bulk carbon with graphite structure. The fast activation and gasification of the carbon species by the oxidative atmosphere around the anode surface are also beneficial factors. The test results indicate also that the activation of CH 3OH is much more difficult than that of H 2. © 2012 The Royal Society of Chemistry.


Li G.,Tianjin University of Technology | Liang M.,Tianjin University of Technology | Wang H.,Tianjin University of Technology | Sun Z.,Tianjin University of Technology | And 3 more authors.
Chemistry of Materials | Year: 2013

Indoline dyes exhibit impressive short-circuit photocurrent (J SC) but show generally low open-circuit voltage (VOC) in dye-sensitized solar cells (DSCs). To retard charge recombination in DSCs, four indoline dyes (XS41, XS42, XS43, and XS44) featuring, respectively, dipropylfluorene, hexyloxybenzene, tert-butylbenzene, and hexapropyltruxene electron donors, have been engineered. The incorporation of bulky rigid groups (i.e., dipropylfluorene and hexapropyltruxene unit) can notably retard the charge recombination at the titania/electrolyte interface. Moreover, we have developed two organic dyes (TC1 and TC2) as alternative coadsorbents to chenodeoxycholic acid (CDCA). Interestingly, it is found that regardless of the dye selection coadsorption with TC2 shows an improved VOC as well as JSC in comparison with its TC1 analogues. Dependence of photovoltage on the structure of TC1/TC2 was also investigated. The results suggest that the change in VOC is likely correlated with the molecular matching between the dyes and the coadsorbents. Combining the two contributions, high VOC in indoline-based DSCs can be realized. The results of XS41, upon coadsorption with TC2, produce a JSC of 16.1 mA cm-2, a VOC of 770 mV, and a fill factor of 0.66, corresponding to a power conversion efficiency of 8.18% under simulated AM1.5G solar light (100 mW cm-2). These findings pave a new way to achieve further efficiency enhancement of indoline dyes. © 2013 American Chemical Society.


Yeh C.-N.,Northwestern University | Raidongia K.,Northwestern University | Shao J.,Northwestern University | Shao J.,Tianjin University of Technology | And 3 more authors.
Nature Chemistry | Year: 2015

Graphene oxide (GO) films are known to be highly stable in water and this property has made their use in membrane applications in solution possible. However, this state of affairs is somewhat counterintuitive because GO sheets become negatively charged on hydration and the membrane should disintegrate owing to electrostatic repulsion. We have now discovered a long-overlooked reason behind this apparent contradiction. Our findings show that neat GO membranes do, indeed, readily disintegrate in water, but the films become stable if they are crosslinked by multivalent cationic metal contaminants. Such metal contaminants can be introduced unintentionally during the synthesis and processing of GO, most notably on filtration with anodized aluminium oxide filter discs that corrode to release significant amounts of aluminium ions. This finding has wide implications in interpreting the processing-structure-property relationships of GO and other lamellar membranes. We also discuss strategies to avoid and mitigate metal contamination and demonstrate that this effect can be exploited to synthesize new membrane materials.


Qin G.,Tianjin University of Technology | Sun Z.,Tianjin University of Technology | Wu Q.,Tianjin University of Technology | Lin L.,Tianjin University of Technology | And 2 more authors.
Journal of Hazardous Materials | Year: 2011

A new strategy to photocatalytic degradation of 4-cholophenol (4-CP) under visible light irradiation was described. The TiO2 film deposited on an ordinary glass sheet was distributed into two zones. One zone was sensitized by N719 dye and fabricated to be a sandwich type cell with a similar structure of dye-sensitized solar cells. The other zone was inserted into pollutants solution for degradation. A highly oxidized overvoltage anode was achieved from the dye-sensitized zone. The bifunctionalized TiO2 film and the anode could degrade 4-chlorophenol in two separate reactors with 97% and 96% removal of 4-CP after 5h, respectively. The degradation efficiency could be improved by addition of FeSO4. The as-prepared bifunctionalized TiO2 film was comparably stable in the process of degradation. © 2011 Elsevier B.V.


Sun X.,Nankai University | Sun X.,Tianjin University of Technology | Shi Y.,Hangzhou Normal University | Zhang P.,University of California at Santa Barbara | And 7 more authors.
Journal of the American Chemical Society | Year: 2011

We report a general reaction container effect in the nanocasting synthesis of mesoporous metal oxides. The size and shape of the container body in conjunction with simply modifying the container opening accessibility can be used to control the escape rate of water and other gas-phase byproducts in the calcination process, and subsequently affect the nanocrystal growth of the materials inside the mesopore space of the template. In this way, the particle size, mesostructure ordering, and crystallinity of the final product can be systemically controlled. The container effect also explain some of the problems with reproducibility in previously reported results. © 2011 American Chemical Society.


Liu C.,Tianjin University of Technology | An J.,Tianjin University of Technology | Guo R.,Tianjin University of Technology | Li Y.,Tianjin University of Technology | Liu L.,Tianjin University of Technology
Journal of Alloys and Compounds | Year: 2013

Highly conductive titanium nitride (TiN) modified LiFePO4/C powders have been prepared via a suspension mixing process followed by heat treatment at 60 °C. The structures and compositions of LiFePO4 samples modified with TiN are characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is found that nano-sized TiN particles together with the amorphous carbon layer form an integrated network on the surface of LiFePO 4. Galvanostatic charge/discharge test indicates that TiN modification is effective to improve the discharge capacity and cycle performance, especially at high rates. Electrochemical impedance spectroscopy (EIS) and potential step chronoamperometry (PSCA) measurements prove that the co-coating layer of C and TiN dramatically alleviates the charge transfer impedance and enhances the Li-ion diffusion coefficient, respectively. The sample with 5 wt.% TiN exhibits the best electrochemical performance among several samples investigated in this work.© 2013 Elsevier B.V. All rights reserved.


Zhu T.,Tianjin University of Technology | Zhu T.,Inha University | Row K.H.,Inha University
Separation Science and Technology (Philadelphia) | Year: 2013

A 17-run Box-Behnken design (BBD) with three factors was used to improve the conditions for extracting astaxanthin from shrimp waste. The astaxanthin level was determined by high performance liquid chromatography (HPLC) using a C18 column and a UV detector at 476 nm. The mean extraction yield of astaxanthin at the improved conditions (extraction time 1.4 h, extraction temperature 72.4°C, and liquid-solid ratio 27.3) was 98.7 ± 2.6 μg g-1. A solid-phase extraction (SPE)-HPLC method was developed with a new hybrid organic-inorganic hybrid monolith for further purification of astaxanthin from shrimp waste. The SPE recoveries were ranging from 81.3 ± 2.4% to 86.5 ± 3.3%, and the intra-day and inter-day relative standard deviations (RSDs) of the proposed method were less than 4.3 ± 0.5% and 4.8 ± 0.2%, respectively. BBD increased the extraction efficiency and shortened extraction times significantly. SPE-HPLC with hybrid monolith showed good selectivity and purified astaxanthin from shrimp waste. © 2013 Copyright Taylor and Francis Group, LLC.


Lin W.,Nankai University | Zhang H.,Nankai University | Song B.,Nankai University | Miao Y.,Tianjin University of Technology | And 3 more authors.
Optics Express | Year: 2015

In this paper, a magnetically controllable wavelength-divisionmultiplexing (WDM) fiber coupler has been proposed and experimentally demonstrated. A theoretical model has been established to analyze the influences of the weak as well as strong couplings to the wavelength tunability of this coupler. Experimental results show that the operation wavelength tunability of the proposed WDM coupler could be fulfilled for an applied magnetic field intensity range of 0 Oe to 500 Oe, and particularly it possesses high operation performances within the magnetic field intensity ranging from 25 Oe to 125 Oe when additional transmission loss and isolation are both considered. Within this range, the two selected channels show the wavelength tunability of 0.05 nm/Oe and 0.0744 nm/Oe, respectively, and the isolation between the two branches is higher than 24.089 dB. Owing to its high isolation, good splitting ratio stability, and high wavelength tunability, the proposed controllable WDM coupler is anticipated to find potential applications in such fields as fiber laser, fiber sensing and fiber-optic communications. Moreover, the fiber coupler integrated with the magnetic fluid would be valuable for the design of magnetically controllable mode-division-multiplexing devices. © 2015 Optical Society of America.


Meng Q.,University of Macau | Li Y.,Tianjin University of Technology | Xu J.,University of Macau
Precision Engineering | Year: 2014

This paper proposes a novel analytical model for flexure-based proportion compliant mechanisms. The displacement and stiffness calculations of such flexure-based compliant mechanisms are formulated based on the principle of virtual work and pseudo rigid body model (PRBM). According to the theory and method, a set of closed-form equations are deduced in this paper, which incorporate the stiffness characteristics of each flexure hinge, together with the other geometric and material properties of the compliant mechanism. The rotation center point for a corner-filleted flexure hinge is investigated based on the finite element analysis (FEA) and PRBM. An empirical equation for the rotational angle is fitted in this paper in order to calculate accurately the position of the end-point of the flexure hinge. The displacement proportion equation for such mechanisms is derived according to the new approach. Combining the new proposed design equation and the existed stiffness equation, a new proportion compliant mechanism with corner-filleted flexure hinges is designed by means of the least squares optimization. The designed models are verified by finite element analysis. © 2013 Elsevier Inc.


Qin J.,Tsinghua University | Lv W.,Tsinghua University | Li Z.,Tianjin University of Technology | Li B.,Tsinghua University | And 3 more authors.
Chemical Communications | Year: 2014

A silver vanadium oxide (SVO) material with an interlaced structure was prepared using graphene as a two-dimensional substrate that directs the crystal growth in the hydrothermal process. The obtained SVO-graphene hybrid showed high structural stability, and lithium ion batteries (LIBs) using the hybrid as the cathode showed excellent cycling stability and rate performance. This journal is © the Partner Organisations 2014.


Li Q.-L.,Jilin University | Gu W.-X.,Tianjin University of Technology | Gao H.,Tianjin University of Technology | Yang Y.-W.,Jilin University | Yang Y.-W.,Nanjing University
Chemical Communications | Year: 2014

In this feature article, we give an overview of the preparation and application of self-assembled architectures based on an emerging area of polymers, i.e., poly(glycidyl methacrylate)s (PGMAs) and their derivatives. A series of PGMA-based aggregates and hybrids, such as micelles, reverse micelles, capsules, nanoparticles, and inorganic-organic hybrid materials, has been constructed, and diverse morphologies were formed, driven by hydrophobic interactions, hydrogen bonding, ionic complexation, host-guest interactions, etc. In particular, the assemblies have shown great potential applications as drug vectors, gene vectors, solubilizing agents, antimicrobial agent, and so forth. Herein, the general guidelines are elaborately selected from literature examples and partially from our own. Although still in its infancy, self-assembly of PGMA-based polymers is expected to become a hot topic in polymer chemistry and materials science. © 2014 the Partner Organisations.


Li Y.,University of Macau | Li Y.,Tianjin University of Technology | Xiao S.,University of Macau | Xi L.,Tianjin University of Technology | Wu Z.,University of Macau
International Journal of Precision Engineering and Manufacturing | Year: 2014

A new XY micro-motion stage is proposed with the double four-bar prismatic joints to transfer linear motions and mechanical displacement amplifier. The compliance models of the amplifier, the prismatic joints, and the whole stage are established based on the flexibility matrix method. The simulation is made by using finite element analysis ANSYS software. The output cross-talk is about 2% and the parasitic motions of the input points in the other limbs are less than 1.8%, which shows a good decoupling property. The mechanical prototype is fabricated, the experimental results show that the input/output of the stage has a very good linearity, the ratio of output displacement to input displacement is 5.06 and the working range is 156 μm × 156 μm. To tackle for the serious hysteresis nonlinear problems of the stage, model reference adaptive PID controller is designed, the final resolution can reach ±0.2 μm. © 2014 Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.


Xiao S.,University of Macau | Li Y.,King Abdulaziz University | Li Y.,Tianjin University of Technology
Journal of Microelectromechanical Systems | Year: 2014

This paper presents a novel micro manipulation system based on visual servo feedback control, which is composed of a micro/nano positioning stage with large workspace, a micro gripper, and a microscope-based visual servo system. The positioning stage is featured with compliant flexure-based totally decoupled characteristics, which is driven by electromagnetic actuators. The gripper is designed with its arms moving completely parallel, which has a large displacement of gripping range. In this research, the gripper is mounted onto the micro positioning stage to form a micro-hand dedicated to micro assembly application. A microscope is adopted to observe this tiny view field and capture the information about the position of the gripping fingers and the objects. Meanwhile, a small piece of silver wire with a diameter of about 30 microns is used as the micro part. The positioning information about tips of the gripping fingers and the object can be captured via the digital microscope and processed by a novel rapid identification method. A kind of visual servo feedback tracking and gripping control algorithm is developed. The algorithm is validated through experiments by realizing the task of picking up a small piece of silver wire then placing it to a new place precisely. © 2013 IEEE.


Qin W.-J.,Tianjin University | Qin W.-J.,Tianjin University of Technology | Sun J.,Tianjin University | Yang J.,Tianjin University | Du X.-W.,Tianjin University
Materials Chemistry and Physics | Year: 2011

Cu doping of ZnO quantum dots (QDs) was carried out by laser ablation of Zn/Cu composite targets immersed in PVP aqueous solution. Zn/Cu core-shell particles were firstly prepared by a galvanic replacement reaction, and then they were pressed into targets with different Zn/Cu ratios for laser ablation. Under the extremely non-equilibrium conditions generated by the pulse laser used, a large amount of Cu-doped ZnO QDs were produced with ultrafine size, good dispersibility, and high stability. On the other hand, the dopant concentration was feasibly controlled from 1.8% to 4.8% by changing the atomic content of Cu in Zn/Cu composite targets. Cu-doped QDs exhibited blue emission with tunable wavelength, which was ascribed to electronic transitions from the conductor band of ZnO to the acceptor levels related to Cu dopants. As a facile and versatile technique, laser ablation is believed to be an effective way for fabricating various doped nanocrystals. © 2011 Elsevier B.V. All rights reserved.


Zhang A.,Tianjin University of Technology
Microwave and Optical Technology Letters | Year: 2011

Multiple mode instabilities in erbium-doped fiber laser are undesirable due to the large amplitude noise in the laser. One scheme is proposed to suppress this kind of instabilities by inserting a highly nonlinear photonic crystal fiber in the ring cavity. The results show that the nonlinear effect not only eliminates the laser instability but also suppresses the noise in the laser. Copyright © 2011 Wiley Periodicals, Inc.


Xia C.,Tianjin University of Technology | Wang L.,Tianjin University of Technology | Sun S.,Tianjin University of Technology | Wang J.,Tianjin University of Technology
Nonlinear Dynamics | Year: 2012

Based on the SIR (Susceptible-Infected- Removed) model, we propose a novel epidemic model to investigate the impact of infection delay and propagation vector on the spreading behaviors in complex networks. Mean-field approximations and extensive numerical simulations indicate that the infection delay and propagation vector can largely reduce the critical threshold and promote the outbreak of epidemics, and even lead to the case that the infectious diseases transform from the disease-free state to endemic one. The current results are greatly instructive for us to further understand the epidemic spreading and design some effective prevention and containment strategies to fight the epidemics. © Springer Science+Business Media B.V. 2011.


Yan F.,Tianjin University of Technology | Xia S.,Tianjin University of Technology | Wang Q.,Tianjin University of Science and Technology | Ma P.,Tianjin University of Technology
Journal of Chemical and Engineering Data | Year: 2012

A new topological index (TI) was proposed based on atom characters (e.g., atom radius, atom electronegativity, etc.) and atom positions in the hydrogen-suppressed molecule structure in our previous work. In this work, the TI was used for predicting the toxicity of ILs in acetylcholin esterase (log EC 50 AChE) by the multiple linear regression (MLR) method. For ILs composed entirely of cations and anions, the TIs are calculated from cations and anions, respectively. The 221 ILs used in the MLR model are based on imidazolium (Im), pyridinium (Pyi), pyrrolidinium (Pyo), ammonium (Am), phosphonium (Ph), quinolinium (Qu), piperidinium (Pi), and morpholinium (Mo). The regression coefficient (R 2) and the overall average absolute error (AAE) are 0.877 and 0.153, respectively. © 2012 American Chemical Society.


Zhang M.,Tianjin University of Technology | Zhu X.,Tianjin University of Technology | Liang X.,Tianjin University of Technology | Wang Z.,Tianjin University of Technology
Catalysis Communications | Year: 2012

An argon glow discharge plasma was used for the reduction of carbon-supported Au catalysts at ambient temperature. The plasma-reduced Au/C sample produced 7-8 nm Au particles that were highly dispersed on carbon. The surface oxygen species on carbon were increased by plasma treatment. Most interestingly, the metal particles were recessed into the carbon substrate. The stronger anchoring enhanced the stability of the active metal loaded on the support. The Au/C catalysts were tested for selective oxidation of glucose to gluconic acid compared with conventional hydrogen reduced catalysts. A significant improvement in glucose oxidation was achieved by the plasma-reduced sample. © 2011 Elsevier B.V. All rights reserved.


Li Y.,Tianjin University of Technology | Wang S.,Tianjin University of Technology | He G.,Tianjin University of Technology | Wu H.,Tianjin University of Technology | And 2 more authors.
Chemical Society Reviews | Year: 2015

In nature, the biological membrane can selectively transport essential small molecules/ions through facilitated diffusion via carrier proteins. Intrigued by this phenomenon and principle, membrane researchers have successfully employed synthetic carriers and carrier-mediated reversible reactions to enhance the separation performance of synthetic membranes. However, the existing facilitated transport membranes as well as the relevant facilitated transport theories have scarcely been comprehensively reviewed in the literature. This tutorial review primarily covers the two aspects of facilitated transport theories: carrier-mediated transport mechanisms and facilitated transport chemistries, including the design and fabrication of facilitated transport membranes. The applications of facilitated transport membranes in energy-intensive membrane processes (gas separation, pervaporation, and proton exchange membrane fuel cells) have also been discussed. Hopefully, this review will provide guidelines for the future research and development of facilitated transport membranes with high energy efficiency. © The Royal Society of Chemistry 2015.


Zhang P.,Tianjin University of Technology | Wang T.,Tianjin University of Technology | Gong J.,Tianjin University of Technology
Advanced Materials | Year: 2015

H2 generation by solar water splitting is one of the most promising solutions to meet the increasing energy demands of the fast developing society. However, the efficiency of solar-water-splitting systems is still too low for practical applications, which requires further enhancement via different strategies such as doping, construction of heterojunctions, morphology control, and optimization of the crystal structure. Recently, integration of plasmonic metals to semiconductor photocatalysts has been proved to be an effective way to improve their photocatalytic activities. Thus, in-depth understanding of the enhancement mechanisms is of great importance for better utilization of the plasmonic effect. This review describes the relevant mechanisms from three aspects, including: i) light absorption and scattering; ii) hot-electron injection and iii) plasmon-induced resonance energy transfer (PIRET). Perspectives are also proposed to trigger further innovative thinking on plasmonic-enhanced solar water splitting. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Ma X.,Tianjin University of Technology | Li K.,Tianjin University of Technology | Bai Y.,Tianjin University of Technology
IEEE Photonics Technology Letters | Year: 2013

The conventional compensation methods exist estimation error because of the sequential estimation process using pilot or training symbols for transmitter in-phase and quadrature (Tx IQ) mismatch in a coherent optical orthogonal frequency division multiplexing system. In this letter, a novel training symbol structure is proposed to overcome the performance degradation in conventional methods. The proposed scheme is composed of two adjacent training symbols. Each training symbol has three subsets: 1) the zero-value subset; 2) its mirror image position subset; and 3) other nonzero-value subset. Then, two estimation processes about channel distortion and Tx IQ mismatch factor are independent. The advantages of the proposed structure are displayed via channel mean square error (MSE) simulation and IQ mismatch factor MSE simulation, and the improvement of bit error rate is shown in simulations simultaneously. © 1989-2012 IEEE.


Miao Y.,Tianjin University of Technology | Miao Y.,Tianjin University | Zhang K.,Tianjin University of Technology | Liu B.,Nankai University | And 4 more authors.
IEEE Photonics Technology Letters | Year: 2013

Long-period gratings (LPGs) were successfully inscribed in microstructured optical fibers (MOFs) filled with ferrofluid using a scanning rm CO2 laser. Its formation mechanism and magnetic field tunability are investigated. The dispersion curve indicates that cladding modes are more viable to be tuned than the core mode for the ferrofluid-filled MOF. The relationship between the phase-matching curve of MOF-based LPG and the magnetic field intensity is theoretically analyzed, and the magnetic-field responses of the LPG with 660-\murm m-pitch and a resonance peak of 967.56 nm are also discussed. The results show that the MOF-based LPG reaches a sensitivity of 1.946 nm/Oe for a magnetic range of 0-300 Oe, demonstrating its potential application as a high-sensitivity magnetic-field sensor. The proposed magnetic-field sensor could detect the weak magnetic field with high accuracy. It has several unique advantages, such as compactness, good wavelength selectivity, high integration, ease of coupling, high flexibility, and extensibility. Consequently, the proposed device with tunable magnetic-field sensitivity is promising for future-related applications. © 1989-2012 IEEE.


Chen S.,Nankai University | Fan F.,Nankai University | Chang S.,Nankai University | Miao Y.,Tianjin University of Technology | And 4 more authors.
Optics Express | Year: 2014

The dielectric property and magneto-optical effects of ferrofluids have been investigated in the terahertz (THz) regime by using THz timedomain spectroscopy. The experiment results show that the refractive index and absorption coefficient of ferrofluid for THz waves rise up with the increase of nanoparticle concentration in the ferrofluid. Moreover, two different THz magneto-optical effects have been found with different external magnetic fields, of which mechanisms have been theoretically explained well by microscopic structure induced refractive index change in the magnetization process and the transverse magneto-optical effect after the saturation magnetization, respectively. This work suggests that ferrofluid is a promising magneto-optical material in the THz regime which has widely potential applications in THz functional devices for THz sensing, modulation, phase retardation, and polarization control.© 2014 Optical Society of America.


Fang W.,Beijing Aeronautical Science and Technology Research Institute | Li J.,Tianjin University of Technology
Lecture Notes in Electrical Engineering | Year: 2016

A new algorithm is proposed in this paper to solve the problem of multisource distance measurement equipment (DME) pulse interference suppression for global positioning system (GPS) L5 signal. The problem can be treated as DME signal estimation, and then can be taken as a problem of optimization. Based on nonlinear least squares (NLS) criterion, using WRELAX iteration method, the optimization problem can be solved to estimate the multisource DME signal. Once DME pulse interference signal is estimated, then it can be reconstructed, and finally can be eliminated and suppressed. Compared with traditional method, the proposed method can reserve more useful GPS satellite data. The performance of proposed method is verified by numerical simulations. © Springer-Verlag Berlin Heidelberg 2016.


Li J.,Tianjin University of Technology | Fang W.,Beijing Aeronautical Science and Technology Research Institute
Lecture Notes in Electrical Engineering | Year: 2016

L5 signal is set up for civil aviation exclusively in GPS (Global Positioning System), and takes up exclusive frequency band. However, the DME (Distance Measurement Equipment) signal which has already applied for distance measurement works as the same frequency band as GPS L5. DME signal with high power will decrease SINR (Signal to Interference and Noise Ratio) of GPS L5 and even give rise to acquisition failure. On DME interference suppression, the traditional methods will bring loss to useful satellite data. Thus the performance of GPS L5 receiver will suffer from serious degradation. In the light of the received signal model, a new DME interference mitigation algorithm is presented in this paper. Firstly, frequency is estimated with time-modulated windowed all-phase DFT (tmwapDFT). Then, we use the estimated frequency to get amplitude and signal delay information with signal separation estimation theory. Compared with traditional method, the proposed method can reserve more useful satellite data. The performance of proposed method is verified by simulations. © Springer-Verlag Berlin Heidelberg 2016.


Zhu B.,Beijing Jiaotong University | Ren G.,Beijing Jiaotong University | Gao Y.,Beijing Jiaotong University | Yang Y.,Tianjin University of Technology | And 2 more authors.
Optics Express | Year: 2014

We propose in this paper a graphene-coated tapered nanowire probe providing strong field enhancement in the infrared regimes. The analytical field distributions and characteristic equation of the supported surface plasmons mode are derived. Based on the adiabatic approximation, analytic methods are adopted in the investigation of field enhancement along the tapered region and show well consistence with the rigorous numerical simulations. Both the numerical and analytical results have shown that the graphene-coated nanowire probe could achieve an order of magnitude larger field enhancement than the metal-coated probes. The proposed probe may have promising applications for single molecule detection, measurement and nano-manipulation techniques. ©2014 Optical Society of America.


Qu Y.,Tianjin University of Technology | Cao J.,Tianjin University of Technology | Guo R.,Tianjin University of Technology | Xu W.,Tianjin University of Technology
Electrochemical and Solid-State Letters | Year: 2012

Carbon coated LiFePO 4 was modified with Sr 0.85Ce 0.15CoO 3- via a suspension mixing process followed by heat treatment. An integrate network formed by Sr 0.85Ce 0.15CoO 3- and carbon was found on the surface of LiFePO 4 particles by high resolution transmission electron microscopy. The co-coating layers alleviated the charge-transfer impedance and facilitated the lithium-ion diffusion. Consequently, the discharge capacity was significantly improved especially at high rates. The sample coated with 3 wt Sr 0.85Ce 0.15CoO 3- showed a high capacity of 94 mAh g -1 compared with that of uncoated sample (65 mAh g -1) at 5C. © 2011 The Electrochemical Society.


Yang L.,Tianjin University of Technology | Zhou S.,Tianjin University of Technology | Ding T.,Tianjin University of Technology | Meng M.,Tianjin University of Technology
Fuel Processing Technology | Year: 2014

A series of Ce1 - xCuxO2 - δ non-stoichiometric solid solutions and their supported copper catalysts CuO/Ce1 - xCuxO2 - δ (x = 0, 0.005, 0.022, 0.043) were prepared by co-precipitation and deposition-precipitation, respectively. The CuO/Ce1 - xCuxO2 - δ catalysts show high performance for CO preferential oxidation (CO PROX). Multiple techniques of N2 sorption (BET), XRD, Laser Raman spectroscopy (LRS), HRTEM, H2-TPR, O2-TPO, N2O chemisorption and in-situ DRIFTS were used for catalyst characterization. The results of XRD, LRS and H2-TPR conformably indicate that a small amount of Cu2 + ions can be incorporated into the lattice of CeO 2, forming non-stoichiometric solid solutions Ce 1 - xCuxO2 - δ, which shows much better reducibility than pure CeO2. The supported CuO/Ce 1 - xCuxO2 - δ catalysts exhibit remarkably enhanced activity for CO PROX as compared with CuO/CeO2, especially the catalyst CuO/Ce0.978Cu0.022O 2 - δ containing 15% Cu, which displays the best CO PROX performance, showing not only the lowest temperature (115 °C) for CO total conversion, but also the 100% selectivity of O2 to CO2 at this temperature. Several aspects including the presence of more oxygen vacancies, the improved reducibility, and stronger capability for CO chemisorption of this catalyst account well for its superior performance for CO PROX. Based upon the in-situ DRIFTS study, it is revealed that Cu+ is the main active site for CO oxidation, while Cu0 is more active for H2 activation and oxidation. © 2014 Elsevier B.V.


Luan N.,Tianjin University of Technology | Yao J.,Tianjin University of Technology
IEEE Photonics Journal | Year: 2016

A surface plasmon resonance (SPR) sensor based on a hollow fiber (HF) is proposed to realize high analyte refractive index (RI) detection. The hole in the HF as a microfluidic channel for the analyte is filled with a silver wire to replace the metal coating. The sensitivity of the proposed SPR sensor with analyte RI from 1.47 to 1.51 is theoretically investigated both in the wavelength and amplitude interrogation methods. The results show that the sensor can support two disparate resonance peaks, with orthogonal polarizations (x- and y-polarized peaks), and the sensitivity of the y-polarized peak is higher than that of x-polarized peak. Moreover, contrary to the performances of the resonance peaks supported by the low RI SPR sensors, the two polarized peaks shift to shorter wavelength as analyte RI increasing and show a higher sensitivity at low analyte RI. These results and analyses, including the abnormal behaviors of resonance peaks and the coupling condition between the core modes and the plasmon modes, are very helpful for the design and improvement of high RI SPR sensors. © 2009-2012 IEEE.


Li J.F.,Tianjin University | Li J.F.,Tianjin University of Technology | Xia C.,Tianjin University | Au C.T.,Hong Kong Baptist University | Liu B.S.,Tianjin University
International Journal of Hydrogen Energy | Year: 2014

A series of Y2O3-promoted NiO/SBA-15 (9 wt% Ni) catalysts (Ni:Y weight ratio = 9:0, 3:1, 3:2, 1:1) were prepared using a sol-gel method. The fresh as well as the catalysts used in CO2 reforming of methane were characterized using N2-physisorption, XRD, FT-IR, XPS, UV, HRTEM, H2-TPR, O2-TPD and TG techniques. The results indicate that upon Y2O3 promotion, the Ni nanoparticles are highly dispersed on the mesoporous walls of SBA-15 via strong interaction between metal ions and the HO-Si-groups of SBA-15. The catalytic performance of the catalysts were evaluated at 700 °C during CH4/CO2 reforming at a gas hourly space velocity of 24 L gcat -1 h-1(at 25 °C and 1 atm) and CH4/CO 2molar ratio of 1. The presence of Y2O3 in NiO/SBA-15 results in enhancement of initial catalytic activity. It was observed that the 9 wt% Y-NiO/SBA-15 catalyst performs the best, exhibiting excellent catalytic activity, superior stability and low carbon deposition in a time on stream of 50 h. © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Dong X.,Nankai University | Zhang H.,Nankai University | Liu B.,Nankai University | Miao Y.,Tianjin University of Technology
Photonic Sensors | Year: 2011

In this paper, the mode coupling mechanism of tilted fiber Bragg gratings (TFBGs) is briefly introduced at first. And a general review on the fabrication, theoretical and experimental research development of TFBGs is presented from a worldwide perspective, followed by an introduction of our current research work on TFBGs at the Institute of Modern Optics, Nankai University (IMONK), including TFBG sensors for single-parameter measurements, temperature cross sensitivity of TFBG sensors, and TFBG-based interrogation technique. Finally, we would make a summary of the related key techniques and a remark on prospects of the research and applications of TFBGs. © The Authors(s) 2010.


Wang J.,Tianjin University of Technology | Zhao Y.,Tianjin University of Technology
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

In this paper, a novel blind separation approach using power spectral density(PSD) is presented. The power spectrum itself is the Fourier transform of the auto-correlation function. Auto-correlation function represents the relationship of long and short-term correlation within the signal itself. This paper using power spectral density and cross power spectral density separate blind mixed source signals. In practice, non-stationary signals always have different PSD. The method is suitable for dealing with non-stationary signal. And simulation results have shown that the method is feasible. © 2011 Springer-Verlag.


Ma Z.,Nankai University | Deng L.,Nankai University | Yang Y.,Nankai University | Zhai H.,Nankai University | Ge Q.,Tianjin University of Technology
Optics Express | Year: 2013

A novel numerical iterative approach is proposed to effectively eliminate the zero-order term and to improve the signal-to-noise ratio of the reconstructed image in off-axis digital holography. The iterations are conducted in the spatial domain, resulting in considerable reduction in the computational time and avoiding the subjectivity involved in selecting a filter window in spectral domain. These advantages promote the application of this approach in real-time detection processes. The feasibility of this approach is confirmed by mathematical deductions and numerical simulations, and the robustness of the proposed approach is tested by means of an experimentally obtained hologram.


Guo X.,Tianjin University of Technology | Li X.,Tianjin University of Technology | Liu N.,Tianjin University of Technology | Ou Z.Y.,Indiana University – Purdue University Indianapolis
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

We theoretically investigate the quantum-noise properties of a pulse-pumped high-gain-fiber optical parametric amplifiers (FOPAs) by using the Bogoliubov transformation in multiple frequency modes to describe the evolution of the nondegenerate signal and idler twin beams. The results show that the noise figure of the FOPA is generally greater than the 3 dB quantum limit unless the joint spectral function is factorable and the spectrum of the input signal well matches the gain spectrum in the signal band. However, the intensity-difference noise of the twin beams, which weakly depends on the joint spectral function, can be significantly less than the shot-noise limit when the temporal modes of the pump and the input signal are properly matched. Moreover, to closely resemble real experimental conditions, the quantum noise of twin beams generated from a broadband FOPA is numerically studied by taking the various kinds of experimental imperfections into account. Our study is not only useful for developing a compact fiber source of twin beams, but also helpful for understanding the quantum-noise limit of a pulse-pumped FOPA in the fiber communication system. © 2013 American Physical Society.


Ping S.,Tianjin University of Technology
Advanced Materials Research | Year: 2014

This article describes a standard document similarity measure, and is used for cultural archives category. And should be used in the classification of cultural archives. The results show that, based on graph model of this representation is valid and feasible. © (2014) Trans Tech Publications, Switzerland.


Meng F.-J.,Tianjin University of Technology
Advanced Materials Research | Year: 2014

Based on economic distance weights matrix, using the R&D input-output panel data sets of high technological industry and traditional industry in 29 provinces in China from 2001 to 2010 and spatial econometric method, this paper analyzes their R&D spillover effects respectively between provinces. The results indicate: Even though R&D in the high technology industry in China are active, the R&D spillover in this industry is lower than that in the traditional industries; R &D capital contributes to R&D output more than R&D labor for high technological industry, while the traditional industry is just the opposite. © (2014) Trans Tech Publications, Switzerland.


Zhao S.,Tianjin University of Technology | Yue H.,Tianjin University of Technology | Zhao Y.,Tianjin University of Technology | Wang B.,Tianjin University of Technology | And 5 more authors.
Journal of Catalysis | Year: 2013

The long-term stability and activity of catalysts are vital for vapor-phase selective hydrogenation of dimethyl oxalate to synthesize ethanol. Boron has been widely employed as a modifier for transition-metal catalysts mainly to, improve selectivity and stability. We introduced boron species by impregnation into silica-supported copper catalysts prepared by an ammonia evaporation hydrothermal method and investigated their catalytic activity and thermal stability for hydrogenation of dimethyl oxalate. The effect on activity mainly depends on the amount of boron and an optimal Cu/B molar ratio of 3 was obtained. The characterization of the catalysts shows that boron-modified Cu/SiO2 facilitates the dispersion of copper species, enhances the metal-support interaction, and suppresses the growth of copper particles during dimethyl oxalate hydrogenation. © 2012 Elsevier Inc. All rights reserved.


Zhai T.,Tianjin University of Technology | Zhai T.,Tianjin University | Di L.,Tianjin Medical College | Yang D.,Tianjin University of Technology | Yang D.,Tianjin University
ACS Applied Materials and Interfaces | Year: 2013

The high-volume resistivity and surface resistance of poly(ether ether ketone)/multiwalled carbon nanotubes (PEEK/MWCNT) composites restrict their use in an electronic field. To decrease the volume resistivity and surface resistance, we metalized the composites by electroless plating. The composites and metal coatings were characterized by SEM, XPS, AFM, EDX, and XRD spectroscopy. The swelling ratio of the composites, volume resistivity of two-side-coated composites, sheet resistance of plated composites, and adhesion between the coating and PEEK/MWCNT were tested. The results are as follows. A high roughness and a small swelling ratio were obtained by swelling in 18 mol/L H2SO4 for 3 min. Most of the MWCNT on the surface were still wrapped with PEEK after swelling. To expose the MWCNT, an environmentally friendly and effective etchant (MnO2-NaH2PO 4-H2SO4) was used. After etching, not only were high roughness and partially exposed MWCNT obtained but also the percentage of hydrophilic groups on the surface was increased. A dense cauliflower-like Ni-P coating was produced, and the exposed MWCNT were embedded in the metal coating after electroless plating for 20 min. The coating exhibited an amorphous structure with a phosphorus content of 11.21 wt %. The volume resistivity of two-side-coated PEEK/MWCNT dropped sharply to 38 Ω·m after electroless plating for 5 min. The sheet resistance decreased with increasing the electroless-plating time, and it dropped to 0.88 Ω/square after electroless plating for 40 min. The adhesion of the coating reached the highest 5 B scale (ASTM D3359) and could even undergo the test 20 times. © 2013 American Chemical Society.


Liu M.,Tianjin University of Technology | Wang H.,Tianjin University of Technology | Han J.,Tianjin University of Technology | Niu Y.,Tianjin University of Technology
Carbohydrate Polymers | Year: 2012

Alkaline pretreatment was applied to enhance hydrogenolysis conversion of cellulose to C2-C3 polyols. The alkali cellulose was obtained by treating cellulose with different concentration of NaOH solution. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) results indicate that the cleavage of cellulose chains occurs and the amorphous part is increased after alkaline treatment, which means the alkali cellulose has more accessible structure. Moreover, the absorbed NaOH crystal in alkali cellulose could make the further reaction perform in weak basic condition. When hydrogenolysis of alkali cellulose over Ru/C was conducted at 433 K, 59.23% of the substrate was converted with 1,2-propanediol and ethylene glycol as main products, whereas the corresponding conversion rate of untreated cellulose was 25.05% and no C2-C3 polyols were detected. These preliminary results suggested the advantages of activating the cellulose by alkaline pretreatment and potentials for efficient conversion of cellulose. Finally the plausible mechanism was also discussed. © 2012 Elsevier Ltd. All rights reserved.


Wu Q.-P.,Tianjin University of Technology | Zhang L.,Tianjin University of Technology | Liang M.,Tianjin University of Technology | Sun Z.,Tianjin University of Technology | Xue S.,Tianjin University of Technology
Solar Energy | Year: 2011

Three organic dyes with D-π-D-π-A structure based on triarylamine, dimethylarylamine, and rhodanine-3-acetic acid moieties are designed and synthesized. Incorporating thiophene moieties into the system affords sensitizers with high molar extinction coefficients. These dyes were applied into nanocrystalline TiO2 dye-sensitized solar cells through standard operations. For a typical device the maximal monochromatic incident photon-to-current conversion efficiency (IPCE) can reach 73%, with a short-circuit photocurrent density (Jsc) of 7.3mA/cm2, an open-circuit voltage (Voc) of 636mV, and a fill factor (ff) of 0.61, corresponding to an overall conversion efficiency (η) of 2.86%. © 2010 Elsevier Ltd.


Lu M.,Tianjin University of Technology | Liang M.,Tianjin University of Technology | Han H.-Y.,Tianjin University of Technology | Sun Z.,Tianjin University of Technology | Xue S.,Tianjin University of Technology
Journal of Physical Chemistry C | Year: 2011

We report here on the synthesis and photophysical/electrochemical properties of three functional triarylamine organic dyes (MXD5-7) as well as their application in dye-sensitized nanocrystalline TiO2 solar cells (DSSCs). For the designed dyes, the nonplanar structures of bis- hexapropyltruxeneamino take the role of electron donor. The introduction of bis-hexapropyltruxeneamino units brought about superior performance over the simple triphenylamine dye, in terms of light-capturing abilities and suppressing dye aggregation. Among three dyes, the DSSCs based on the dye MXD7 showed the best photovoltaic performance: a short-circuit photocurrent density (J SC) of 11.8 mA cm-2, an open-circuit photovoltage (V OC) of 772 mV, and a fill factor (ff) of 0.68, corresponding to an overall conversion efficiency of 6.18% under 100 mW cm-2 irradiation. These dyes exhibited high VOC values, possible origin for which was investigated regarding the TiO2 surface blocking, conduction band movement, and electrolyte-dye interaction. © 2010 American Chemical Society.


Gao D.,Tianjin University of Technology | Guo R.,Tianjin University of Technology
Journal of the American Ceramic Society | Year: 2010

BaZr0.9Y0.1O2.95 powders were synthesized using both gel-casting process and solid-state reaction. The gel-casting process with citric acid as the complexing agent could result in nanoparticles with a single perovskite phase. Lower calcining temperature and shorter holding time were required to synthesize the BaZr0.9Y0.1O 2.95 powders than the traditional solid-state reaction method. The work demonstrates that the gel-casting process is a simple, fast, and convenient method for preparing a high-temperature proton conductor BaZr 0.9Y0.1O2.95 powder. © 2010 The American Ceramic Society.


Chen Z.,Tianjin University of Technology | Li X.,Tianjin University of Technology
Key Engineering Materials | Year: 2011

Furnace as a control system whose conditions complex, parameter changing, great runing inertia,control action delay. Of which there are many uncertainties,such as air, fuel gas pressure and the frequent fluctuations of the fuel's calorific value. The impact of mutual interference and coupling between the variables to the furnace can not be ignored, though it's not dominant.The systerm based on control model use an advanced generalized predictive control (GPC) algorithm control mode.It can improve the control accuracy of regulator action when the furnace is at the condition of stability.The experiment results show that ducoupling GPC algorithm has a good convergence effect. © (2011) Trans Tech Publications, Switzerland.


Gu Y.,Tianjin University of Technology | Zheng G.,Tianjin University of Technology | Dai M.,Tianjin University of Technology
Computing in Cardiology | Year: 2011

Baseline wander always exists along with ECG signal. It is a kind of noise and may interference the diagnosis of cardio diseases, especially for the automatic diagnosis. Most methods could eliminate baseline wander already, however be difficult to meet the requisition of low distortion. To solve this problem, a morphology algorithm based on 2-D flat structure element is proposed, where flat structure element is often employed in previous work. The structure element is designed according to the shape, amplitude, period of the ECG signal itself, for a more accurate approximating to the ECG waveforms. Moreover, such structure element is variable by the feedback of filtered waveforms, which could elevate its robust. This algorithm is tested with the data from 8 files of MIT/BIH arrhythmia database, which contains 8 different shapes in ST segment, covering most of the cardiac conditions. The results are estimated in the baseline elimination as well as the distortion induced by filtering on the P waveform, QRS wave group, and the ST segments of ECG signal. Compared with those arguments of several classical strategies, the signal to noise ratio after processed by morphology based on non-flat structure element reaches the highest among all methods, and the ratio of deformation lowest, which means that this algorithm could both reduce the baseline wander, and control the distortion effectively. © 2011 CCAL.


Cui L.,Tianjin University of Technology | Li X.,Tianjin University of Technology | Zhao N.,Tianjin University of Technology
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

The photonic crystal fiber (PCF) is one of the excellent media for generating photon pairs via spontaneous four-wave mixing. Here we study how the inhomogeneity of PCFs affect the spectral properties of photon pairs from both the theoretical and experimental aspects. The theoretical model shows that the photon pairs born in different places of the inhomogeneous PCF are coherently superposed, and a modulation in the broadened spectrum of phase-matching function will appear, which prevents the realization of spectral factorable photon pairs. In particular, the inhomogeneity induced modulation can be examined by measuring the spectrum of the individual signal or idler field when the asymmetric group-velocity matching condition is approximately fulfilled. Our experiments are performed by tailoring the spectrum of pulsed pump to satisfy the specified phase-matching condition. The observed spectra of individual signal photons, which are produced from different segments of the 1.9 m inhomogeneous PCF, agree with the theoretical predictions. The investigations are not only useful for fiber-based quantum state engineering, but also provide a dependable method to test the homogeneity of PCF. © 2012 American Physical Society.


Xiao W.,Tianjin University of Technology | Yin W.,Tianjin University of Technology | Xia S.,Tianjin University of Technology | Ma P.,Tianjin University of Technology
Carbohydrate Polymers | Year: 2012

Cellulose resource has got much attention as a promising replacement of fossil fuel. The hydrolysis of cellulose is the key step to chemical product and liquid transportation fuel. In this paper a serials of chloride, acetate, and formate based ionic liquids were used as solvents to dissolve cellulose. The cellulose regenerated from ILs was characterized by FTIR and X-ray powder diffraction. From the characterization and analysis, it was found that the original close and compact structure has changed a lot. After enzymatic hydrolysis, different kinds of ionic liquids (ILs) have different yields of the reducing sugar (TRS). They are 100%, 90.72%, and 88.92% from 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]), 1-butyl-3-methylimidazolium formate ([BMIM][HCOO]) respectively after enzymatic hydrolysis at 50 °C for 5 h. The results indicated that the yields and the hydrolysis rates were improved apparently after ILs pretreatment comparing with the untreated substrates. © 2011 Elsevier Ltd. All rights reserved.


Xu M.-H.,Tianjin University of Technology | Cai F.-S.,Tianjin University of Technology | Yin J.,Tianjin University of Technology | Yuan Z.-H.,Tianjin University of Technology | Bie L.-J.,Tianjin University of Technology
Sensors and Actuators, B: Chemical | Year: 2010

Well-dispersed SnO2 nanosheets were obtained by the reaction of SnCl2·5H2O and CO(NH2)2 on Al2O3 tube using homogeneous precipitation method. The morphology, size and phase of the nanosheets were analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD). A novel micro gas sensor based on as-prepared SnO2 nanosheets was successfully fabricated. The gas-sensing results show that the sensor response of SnO2 nanosheets sensor reaches 48.377 to 100 ppm ethanol with a response time less than 8 s. © 2010 Elsevier B.V. All rights reserved.


Li Z.Q.,Tianjin University of Technology
Applied Mechanics and Materials | Year: 2013

Planner multi-bar mechanisms are widely used in the machinery industry. In this article, a typical planner six-bar mechanism is researched. The kinematics and dynamics mathematical model is established for this kind of mechanism. On the basis of it, a relevant simulation is carried out through MATLAB/Simulink. Thus, the motion rules and stress state for all parts of the mechanism are described vividly. The simulation results show that this method is much more effective and efficient when the simulation is implemented for a certain machine system. Meanwhile, it provides a theoretical foundation and a better analytical approach of simulation for the design and analysis of complex multi-linkage mechanisms in the future. © (2013) Trans Tech Publications, Switzerland.


Yan T.,University of Texas at Austin | Gong J.,University of Texas at Austin | Gong J.,Tianjin University of Technology | Flaherty D.W.,University of Texas at Austin | And 2 more authors.
Journal of Physical Chemistry C | Year: 2011

The effect of moisture on CO oxidation on Au/TiO2(110) model catalysts is investigated using temperature-programmed desorption and molecular beam reactive scattering under ultrahigh vacuum (UHV) conditions. Oxygen exchange is observed between adsorbed atomic oxygen and isotopically labeled water. Coadsorbed water (H2 18O) takes part in CO oxidation on Oa precovered Au/TiO2(110) model catalysts, leading to the formation of C16O18O and C16O 16O. The amount of C16O18O produced increases with increasing water coverages; however, the total amount of CO2 produced decreases. Although coadsorbed Oa and H2O have a minimal influence on the initial adsorption probability of CO, the total uptake of CO decreases as H2O coverages increase. Interestingly, the adsorption of water induces desorption of predeposited molecularly chemisorbed O2. Thus, adsorbed water slightly inhibits CO oxidation on atomic oxygen precovered Au/TiO2(110) model catalysts under UHV conditions. © 2010 American Chemical Society.


Zou Z.-Q.,Tianjin University of Technology | Meng M.,Tianjin University of Technology | He J.-J.,Tianjin University of Technology
Materials Chemistry and Physics | Year: 2010

A series of lean-burn NOx trap (LNT) catalysts Pt/K/Al 2O3-TiO2-ZrO2 were prepared by sequential impregnation. By altering support calcination temperature and K loading, the distribution state of the storage medium K on different catalysts is carefully investigated. Pyridine-IR results show that a lot of hydroxyl groups exist on the supports calcined at low temperatures (<800 °C), which can react with the supported K2CO3, possibly forming -OK groups. The in situ DRIFTS results indicate that the dominant NO x storage species are monodentate or/and bidentate nitrates. As the calcination temperature is increased to 800 °C or higher, much less hydroxyl groups are detected on the surface of Al2O3-TiO 2-ZrO2. In this case, most potassium exists in the form of K2CO3 on Al2O3-TiO 2-ZrO2, which can transform to free ionic nitrates during NOx storage. High K loading and high calcination temperature facilitate the formation of K2CO3, which possesses higher NOx storage efficiency but lower sulfur resisting and regeneration ability than -OK groups. © 2010 Elsevier B.V. All rights reserved.


Li S.,Tianjin University of Technology | Zhang C.,Tianjin University of Technology | Zhang P.,Tianjin University of Technology | Wu G.,Tianjin University of Technology | And 2 more authors.
Physical Chemistry Chemical Physics | Year: 2012

This paper describes a strategy for producing hydrogen via steam reforming of ethylene glycol over supported nickel catalysts. Nickel plays a crucial role in conversion of ethylene glycol and production of hydrogen, while oxide supports affect product distribution of carbonaceous species. A plausible reaction pathway is proposed based on our results and the literature. This journal is © the Owner Societies 2012.


Zhang C.,Tianjin University of Technology | Zhang P.,Tianjin University of Technology | Li S.,Tianjin University of Technology | Wu G.,Tianjin University of Technology | And 2 more authors.
Physical Chemistry Chemical Physics | Year: 2012

This paper describes the utilization of skeletal Ni-based catalysts for steam reforming of ethanol to produce CO-free hydrogen, which could be superior in the application of fuel cells. Assistant metals play different roles in the reaction; Pt and Cu suppress the methanation and enhance H 2 production, while Co promotes the methanation. © the Owner Societies 2012.


Xia C.-Y.,Tianjin University of Technology | Wang L.,Tianjin University of Technology | Wang J.,Tianjin University of Technology | Wang J.-S.,Tianjin University of Technology
Communications in Theoretical Physics | Year: 2012

We combine the Fermi and Moran update rules in the spatial prisoner's dilemma and snowdrift games to investigate the behavior of collective cooperation among agents on the regular lattice. Large-scale simulations indicate that, compared to the model with only one update rule, the cooperation behavior exhibits the richer phenomena, and the role of update dynamics should be paid more attention in the evolutionary game theory. Meanwhile, we also observe that the introduction of Moran rule, which needs to consider all neighbor's information, can markedly promote the aggregate cooperation level, that is, randomly selecting the neighbor proportional to its payoff to imitate will facilitate the cooperation among agents. Current results will contribute to further understand the cooperation dynamics and evolutionary behaviors within many biological, economic and social systems. © 2012 Chinese Physical Society and IOP Publishing Ltd.


Wang J.,Tianjin University of Technology | Zhang H.,Nankai University | Yang X.,Nankai University | Jiang S.,Tianjin University of Technology | And 3 more authors.
Advanced Functional Materials | Year: 2011

Water retention is a pervasive issue in agriculture and industry. Inspired by the water-storage mechanisms in plant cells, three kinds of polymeric microcapsules (PMCs) with carboxylic acid, sulfonic acid, and pyridyl groups are prepared using distillation-precipitation polymerization. The size of the lumen of the PMCs may govern the static water uptake by holding water molecules in a free-water state, and the functional groups in the shell of PMCs may manipulate dynamic water release by holding water molecules in a bound-water state, thus yielding PMCs with high and tunable water-retention properties. Incorporation of PMCs into composite membranes gives rise to dramatically enhanced water-retention properties and proton-transfer pathway, and consequently increased proton conductivity by up to one order of magnitude over the control polymer membrane, under low relative humidity of 20%. This study may offer a facile and generic strategy to design and prepare a variety of materials with superior water-retention properties. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Huang J.,University of Macau | Li Y.,Tianjin University of Technology
2010 IEEE International Conference on Automation and Logistics, ICAL 2010 | Year: 2010

Based on flexure hinges, a novel two-degree-of-freedom (2-DOF) compliant parallel micromanipulator driven by piezoelectric actuator (PZT) is presented in this paper. According to the designed mechanism structure, a pseudo rigid body (PRB) model is set up, and then the kinematics and statics are studied in a polar coordinate system. The workspace analysis is given subsequently according to the motion ranges of flexure hinges and actuators. To examine the static performance of the mechanism and verify the accuracy of the established kinematic model, finite element analysis (FEA) is carried out using ANSYS software. The simulation result also reveals that the mechanism has ideal linearity in terms of the kinematic and static properties. © 2010 IEEE.


Yu H.,Tianjin University of Technology
Applied Mechanics and Materials | Year: 2014

Some researches on the key technologies of automatic fare collection (AFC) system in the rail transit are conducted systematically in this article. Besides, the studies on the station device application conditions of AFC system and the functional analysis of the ticket machine, the gate and the station computer system in Tianjin Metro are taken in detail. © (2014) Trans Tech Publications, Switzerland.


Yang S.,Tianjin University of Technology
19th International Conference on Industrial Engineering and Engineering Management: Engineering Management | Year: 2013

The research based on the theory of facilities management theory, and it puts forward the scientific and rational large centralized management model of Tianjin Station Facilities Project. The model solves the problem of Tianjin Railway Station Project that investors are not clear and unclear property rights, and making the equipment system achieves the desired function, and the hub project gets efficient operation, and it achieved win-win social and economic benefits. © 2013 Springer-Verlag Berlin Heidelberg.


Wang Y.,Nankai University | Wu G.,Nankai University | Li X.,Nankai University | Chen J.,Nankai University | And 2 more authors.
Journal of Materials Chemistry | Year: 2012

A series of biodegradable poly(ether urethane)s that responded to changes in temperature and redox potential was synthesized via a facile one-pot method. The amphiphilic poly(ether urethane)s were comprised of 2,2′- dithiodiethanol, hydrophobic hexamethylene diisocyanate and hydrophilic poly(ethylene glycol) (PEG) segments. The phase transition temperature (T p) of the prepared poly(ether urethane)s in aqueous solution could be easily controlled by changing the length of the PEG segment or the ratio of PEG to 2,2′-dithiodiethanol and it could be used to trigger the redox-degradable behavior. The redox-responsive disulfide bonds in the polymers could be cleaved in the presence of glutathione (GSH) when the temperature was above Tp, while the degradation was inhibited below Tp. The doxorubicin (DOX)-loaded poly(ether urethane) nanoparticles were prepared in order to investigate their stimuli-responsive release. These nanoparticles also showed a temperature-triggered redox-degradable release profile. Toxicity tests showed that the blank nanoparticles had no toxicity, whereas the DOX-loaded nanoparticles showed high cytotoxicity for liver hepatocellular cells (HepG2). Microscopic observations also revealed that the DOX molecules within the poly(ether urethane) nanoparticles could be released into HepG2 cells in the presence of higher temperature and GSH. © 2012 The Royal Society of Chemistry.


Wei D.,Tianjin University of Technology | Zhang X.,Tianjin University of Technology
Fluid Phase Equilibria | Year: 2013

The solubility of puerarin in methanol and acetic acid solvent mixtures was measured by a static analytical method at temperatures ranging from (293.15 to 333.15)K. The mass fraction of acetic acid in the solvent mixtures (w3) ranges from 0 to 0.6. The Apelblat equation was applied for correlating the experimental solubility data, and subsequently used to derive the apparent molar enthalpy, Gibbs energy, and entropy of dissolution of puerarin in methanol+acetic acid binary mixtures. © 2012 Elsevier B.V.


Zhang Y.,South China University of Technology | Mo G.,South China University of Technology | Li X.,South China University of Technology | Zhang W.,South China University of Technology | And 4 more authors.
Journal of Power Sources | Year: 2011

Graphene with a Brunauer-Emmett-Teller (BET) specific surface area of 264 m2 g-1 has been used as anodic catalyst of microbial fuel cells (MFCs) based on Escherichia coli (ATCC 25922). The electrochemical activities of plain stainless steel mesh (SSM), polytetrauoroethylene (PTFE) modified SSM (PMS) and graphene modified SSM (GMS) have been investigated by cyclic voltammetry (CV), discharge experiment and polarization curve measurement. The GMS shows better electrochemical performance than those of SSM and PMS. The MFC equipped with GMS anode delivers a maximum power density of 2668 mW m-2, which is 18 times larger than that obtained from the MFC with the SSM anode and is 17 times larger than that obtained from the MFC with the PMS anode. Scanning electron microscopy (SEM) results indicate that the increase in power generation could be attributed to the high surface area of anode and an increase in the number of bacteria attached to anode. © 2011 Elsevier B.V. All rights reserved.


Wang C.J.,Tianjin University of Technology | Ge L.,Tianjin University of Technology | Lee T.Y.,China Automotive Technology and Research Center
Applied Mechanics and Materials | Year: 2014

Aimed at the defects and deficiencies of traditional automotive ECU (Electronic Control Unit) development methods, AUTOSAR as a new standard for automotive software development makes the software development process simplified greatly. The existing AUTOSAR development tools are studied and compared in this article to analyze of their respective characteristics, and an ECU software design scheme of the system is summarized according to the methodology. The research results prove that AUTOSAR can raise the development efficiency and software portability. © (2014) Trans Tech Publications, Switzerland.


Hou X.,Tianjin University of Technology | Yang X.,Tianjin University of Technology | Cui L.,Tianjin University of Technology | Zhou G.,Tianjin University of Technology
Materials and Design | Year: 2014

In this paper, AA6061-T4 T-joints with three different joint geometries of T-lap/T-butt-lap/T-butt were fabricated successfully by friction stir welding. The distributions and formation mechanisms of defects in friction stir welded (FSWed) T-joints were discussed through macro and micro-observations, respectively. Hardness profiles of the as-welded samples were also measured to evaluate the softening effect during the process. What's more, influences of joint geometry and the traverse speed on the tensile properties of FSWed T-joints were investigated. All the experimental results indicate that tunnel defects and kissing bond are easily formed and vary significantly in T-joints of the three joint geometries. Defects are moderated to a large extent with decreasing the traverse speed, but the specific relationship to tensile properties is complicated. T-lap joints present the superior tensile properties along the skin direction among the three geometries, the same as T-butt joints along the stringer direction. All the as-welded samples almost fractured in the locations of softening zones and bonding surfaces. © 2013 Elsevier Ltd.


Ding R.,Nankai University | Liao Y.,Nankai University | Liu J.-Y.,Tianjin University of Technology | Wang K.,Zhejiang University
Journal of Cosmology and Astroparticle Physics | Year: 2013

We consider the proposal that dark matter (DM) is composed of a spin-3/2 Diractype particle that is a singlet of the standard model (SM). Its leading effective interactions with ordinary matter involve a pair of their fields and a pair of SM fermions, in the form of products of chiral currents. We make a comprehensive analysis on possible phenomenological effects of the interactions in various experiments and observations. These include collider searches for monojet plus missing transverse energy events, direct detections of DM scattering off nuclei, possible impacts on the gamma rays and antiproton-to-proton flux ratio in cosmic rays, and the observed relic density. The current data already set strong constraints on the effective interactions in a complementary manner. The constraint from collider searches is most effective at a relatively low mass of DM, and the antiproton-to-proton flux ratio offers the best bound for a heavy DM, while the spin-independent direct detection is the best in between. Putting all constraints together, a DM mass less than ∼ 1 TeV has been excluded, leaving behind a small window for a heavy DM particle of spin-3/2. © 2013 IOP Publishing Ltd and Sissa Medialab srl.


Wang H.,Tianjin University of Technology | Zhao L.Y.,Tianjin University of Technology | Chen W.,Tianjin University of Technology
Applied Mechanics and Materials | Year: 2014

Proposing an obstacle avoidance method for mobile robot under unknown environment, which makes use of multiple ultrasonic sensors coordinating with each other and collects position information of obstacles followed by information fuzzy processing, applies artificial potential field method with improved potential function to project the travel path of the robot. It has solved the deadlock problem of the traditional artificial potential field method and achieved obstacle avoidance of mobile robot under unknown environment. By simulation analysis, robot obstacle avoidance can be implemented flexibly using this method. © (2014) Trans Tech Publicutions, Switzerland.


Mao Z.-Y.,Tianjin University of Technology | Wang D.-J.,Tianjin University of Technology | Wang D.-J.,Tianjin Key Laboratory of Photoelectronic Materials and Devices
Inorganic Chemistry | Year: 2010

The generation of direct white-light emission of the coexisting valence-varied europium-lanthanum aluminate through substitution of cations into the host and its resultant adjustment of the energy transfer have been presented. With respect to La0.99-xSrxAlO 3-σ:Eu0.01 and La0.994Al 1-xO3-σ:Eu0.006, and Mnx, Li0.012, the green-light emission positioned at 515 nm plays a key role to color mix for white light and can be efficiently tuned by adjusting the transfer of energy and relevant transition emissions between the luminous centers of Eu2+ and Eu3+/Mn2+, via varying amounts of dopants. Direct white-light emission with optimized values of 86 for the color rendering index and 5091 K for the correlated color temperature has been achieved for lanthanum aluminate by this mixed-valence means. © 2010 American Chemical Society.


Li H.D.,Tianjin University of Technology | Zhao L.Y.,Tianjin University of Technology
Applied Mechanics and Materials | Year: 2014

The image edge detection algorithm is one of the most important steps in the image processing, however, while the large amount of data is need to be dealt with in the detection process, it is difficult to meet real-time requirements by using the software method. In order to improve the speed of digital image processing, An embedded processing systems based on FPGA (field-programmable gate array) detection algorithm is proposed, which takes corrosion expansion algorithm of mathematical morphology as its theoretical basis to achieve the task of image edge detection, experiments result show the method is effective and feasible, and meets the real-time requirement of the image processing. © (2014) Trans Tech Publications, Switzerland.


Sun J.,University of Toyama | Li X.,University of Toyama | Taguchi A.,Tianjin University of Technology | Abe T.,Tianjin University of Technology | And 4 more authors.
ACS Catalysis | Year: 2014

For coping with the increasing petroleum crisis, an efficient conversion of syngas (CO + H2) to gasoline-ranged isoparafins has been paid more and more attention. Here, we report a metallic bifunctional catalyst for this conversion, consisting of highly dispersed Ru nanoparticles (NPs) and H-Beta zeolite support, prepared by a self-made polygonal barrel-sputtering process. The HRTEM and chemisorption results indicated that sputterd Ru NPs exhibited a high metal dispersion of 31.2% with a narrow diameter of 2-4 nm. These metallic Ru NPs were bonded with the acidic zeolite by a weakly physical force, clearly different from the conventional impregnated one. Without any reduction pretreatment, the Ru/H-Beta catalyst could be directly used in Fischer-Tropsch synthesis, showing a CO conversion of 1.6 times as much as the impregnated one. Furthermore, the short distance between sputtered Ru and acidic sites nearby was responsible for the enhanced Ciso/Cn ratio of 4.6, the highest value of gasoline-ranged hydrocarbons among the relevant reports. © 2013 American Chemical Society.


Sun B.,Tianjin University of Technology | Sun J.,Tianjin University of Technology
Proceedings - International Conference on Natural Computation | Year: 2016

Considering the dynamics and uncertainty, this paper proposes a supply chain dynamic formation strategy of multi-modal transport based on multi-agent, which focuses on dynamic building a transportation scheme to meet the requirement of the consignor through negotiation and interaction among agents. The formation includes network initialization, network preprocessing, spatial compatibility judgment and supply chain formation. To accelerate the convergence of the negotiation process, an induction mechanism is designed, and Lagrange relaxation algorithm is also adopted to solve the temporal constrained shortest path problem. The simulation experiments show that the formation strategy can efficiently provide an effective near optimal solution for most of the instances. © 2015 IEEE.


Zhang P.,Tianjin University of Technology | Zhao Y.,Tianjin University of Technology | Haitao W.,University of Jinan
Dalton Transactions | Year: 2015

The dependence of microwave dielectric properties on the structural characteristics of ZnZr(Nb1-xAx)2O8 (A = Ta, Sb) (0 ≤ x ≤ 0.10) ceramics is investigated. All the compounds were prepared by a conventional solid-state reaction method and analyzed via multiphase structure refinement. The diffraction patterns of ZnZr(Nb1-xAx)2O8 (A = Ta, Sb) show the monoclinic wolframite structure of ZrZrNb2O8 which consists of an oxygen octahedron, with the Nb ion in the center of the oxygen octahedron. For the ZnZr(Nb1-xAx)2O8 (A = Ta, Sb) ceramics, the dielectric constant (εr) decreased with the decrease in Nb-site bond ionicity. The quality factor (Q × f) of ZnZr(Nb1-xSbx)2O8 ceramics was found to be the highest (89400 GHz), which is explained in terms of the average of the Nb-site lattice energy. With the decrease in the bond energy of the Nb-site, the temperature coefficient of resonant frequency (τf) value increased. The substitution of A5+ (A = Ta, Sb) for Nb5+ effectively influences the microstructure and microwave dielectric properties of ZrZrNb2O8 ceramics. © The Royal Society of Chemistry 2015.


Li Y.,Tianjin University | Li Y.,Tianjin University of Technology | Chen H.,Tianjin University
Journal of Materials Chemistry A | Year: 2016

A novel fire treatment was adopted to activate two types of hematite photoanodes (sol-gel thin films and hydrothermal nanowires), which successfully removed the surface trap states (surface hydroxyls) on hematite. An optimized photocurrent density of 2.63 mA cm-2 was observed at 1.23 V vs. RHE. © The Royal Society of Chemistry 2016.


Chen X.-D.,Tianjin University of Technology
2013 25th Chinese Control and Decision Conference, CCDC 2013 | Year: 2013

For transportation Networks that can be staging, we suggest a combination optimization model of multiple transportation modes. By constructing a virtual transportation networks, the original problem is converted to a specific shortest path problem. First optimize the network, and then this paper gives the application of genetic algorithm for this problem. © 2013 IEEE.


Jiang H.,Tianjin University of Technology | Jiang H.,Tianjin University | Jiang H.,Shandong Haihua Group Co. | Zhao J.,Tianjin University of Technology | And 2 more authors.
Catalysis Letters | Year: 2014

A series of manganese-cerium oxide (MnOx-CeO2) catalysts were successfully prepared by supercritical antisolvent process and used for low temperature selective catalytic reduction (SCR) of NOx with NH 3. The physicochemical properties of the catalysts were studied by using high-resolution transmission electron microscope, N2 adsorption, X-ray diffraction, X-ray photoelectron spectra, Raman spectra and temperature programmed reduction etc. Hollow spherical morphologies, nanocrystalline structures and solid solution structures were detected for these catalysts. The most active hollow nanospheres were obtained with a molar Mn/(Mn?Ce) ratio of 0.32 and a calcination temperature of 500 °C. Higher surface area, better oxygen mobility and richer surface active oxygen species are responsible for the good performance. The hollow MnOx- CeO2 nanospheres can be a new alternative for the lowtemperature SCR catalysts. © Springer Science+Business Media New York 2013.


Zhu H.,Zhejiang Sci-Tech University | Lyu F.,Tianjin University of Technology | Du M.,Zhejiang Sci-Tech University | Zhang M.,Zhejiang Sci-Tech University | And 3 more authors.
ACS Applied Materials and Interfaces | Year: 2014

Two-dimensional MoS2 nanoplates within carbon nanofibers (CNFs) with monolayer thickness, nanometer-scale dimensions and abundant edges are fabricated. This strategy provides a well-defined pathway for the precise design of MoS2 nanomaterials, offering control over the evolution of MoS2 morphology from nanoparticles to nanoplates as well as from mono- to several-layer structures, over a lateral dimension range of 5 to 70 nm. CNFs play an important role in confining the growth of MoS2 nanoplates, leading to increases in the amount of exposed edge sites while hindering the stacking and aggregation of MoS2 layers, and accelerating electron transfer. The controlled growth of MoS2 nanoplates embedded in CNFs is leveraged to demonstrate structure-dependent catalytic activity in the hydrogen evolution reaction (HER). The results suggest that increases in the number of layers and the lateral dimension result in a decrease in HER activity as a general rule. Single-layer MoS2 nanoplates with abundant edges and a lateral dimension of 7.3 nm demonstrated the lowest hydrogen evolution reaction overpotential of 93 mV (J = 10 mA/cm2), the highest current density of 80.3 mA/cm2 at η = 300 mV and the smallest Tafel slope of 42 mV/decade. The ability of MoS2-CNFs hybrids to act as nonprecious metal catalysts indicates their promise for use in energy-related electrocatalytic applications. © 2014 American Chemical Society.


Zhang S.,Tianjin University of Technology | Liu H.,Nankai University | Mu G.,Nankai University
Optics Letters | Year: 2012

A semianalytical Fabry-Perot model is presented to investigate the electromagnetic enhancement by double grooves in gold substrate. The influence of hybrid wave (HW) propagating along the metal surface on field enhancement is explored systematically with a HW model. Simulation results imply that the hybrid generated by one groove can affect the mode fields in the other groove after propagating along the metallic surface. Giant electromagnetic field intensity at resonance condition is found for the groove distance of 0.6? with the contribution of surface waves,which is nearly independent of the incidence wavelength and groove width. © 2012 Optical Society of America.


Zhao N.,Tianjin University of Technology | Yang L.,Tianjin University of Technology | Li X.,Tianjin University of Technology
Optics Letters | Year: 2012

We study a novel scheme named the spontaneous parametric fiber loop (SPFL), configured by deliberately introducing dispersive elements into the nonlinear Sagnac loop, and show it can function as a passive switch of photon pairs. The two-photon state coming out of SPFL highly depends on the dispersion induced phase difference of photon pairs counterpropagating in the loop. By properly managing the dispersive elements, the signal and idler photons of a pair with a certain detuning and bandwidth can be directed to the desired spatial modes of SPFL. If the photon pairs are used to generate heralded single photons, the SPFL can be viewed as a switch of single photons. Moreover, our investigation about the dispersion based phase modulation is also beneficial for designing all fiber sources of entangled photon pairs. © 2012 Optical Society of America.


Huang Z.-F.,Tianjin University of Technology | Pan L.,Tianjin University of Technology | Zou J.-J.,Tianjin University of Technology | Zhang X.,Tianjin University of Technology | Wang L.,Tianjin University of Technology
Nanoscale | Year: 2014

Water oxidation is the key step for both photocatalytic water splitting and CO2 reduction, but its efficiency is very low compared with the photocatalytic reduction of water. Bismuth vanadate (BiVO4) is the most promising photocatalyst for water oxidation and has become a hot topic for current research. However, the efficiency achieved with this material to date is far away from the theoretical solar-to-hydrogen conversion efficiency, mainly due to the poor photo-induced electron transportation and the slow kinetics of oxygen evolution. Fortunately, great breakthroughs have been made in the past five years in both improving the efficiency and understanding the related mechanism. This review is aimed at summarizing the recent experimental and computational breakthroughs in single crystals modified by element doping, facet engineering, and morphology control, as well as macro/mesoporous structure construction, and composites fabricated by homo/hetero-junction construction and co-catalyst loading. We aim to provide guidelines for the rational design and fabrication of highly efficient BiVO4-based materials for water oxidation. © The Royal Society of Chemistry 2014.


Pan Y.-X.,Southern Illinois University Carbondale | Pan Y.-X.,Tianjin University of Technology | Liu C.-J.,Tianjin University of Technology | Mei D.,Pacific Northwest National Laboratory | Ge Q.,Southern Illinois University Carbondale
Langmuir | Year: 2010

The effects of hydration and oxygen vacancy on CO2 adsorption on the β-Ga2O3(100) surface have been studied using density functional theory slab calculations. Adsorbed CO2 is activated on the dry perfect β-Ga2O3(100) surface, resulting in a carbonate species. This adsorption is slightly endothermic, with an adsorption energy of 0.07 eV. Water is preferably adsorbed molecularly on the dry perfect β-Ga2O3(100) surface with an adsorption energy of ?0.56 eV, producing a hydrated perfect β-Ga2O 3(100) surface. Adsorption of CO2 on the hydrated surface as a carbonate species is also endothermic, with an adsorption energy of 0.14 eV, indicating a slightly repulsive interaction when H2O and CO 2 are coadsorbed. The carbonate species on the hydrated perfect surface can be protonated by the coadsorbed H2O to a bicarbonate species, making the CO2 adsorption exothermic, with an adsorption energy of ?0.13 eV. The effect of defects on CO2 adsorption and activation has been examined by creating an oxygen vacancy on the dry β-Ga2O3(100) surface. The formation of an oxygen vacancy is endothermic, by 0.34 eV, with respect to a free O2 molecule in the gas phase. Presence of the oxygen vacancy promoted the adsorption and activation of CO2. In the most stable CO2 adsorption configuration on the dry defective β-Ga2O 3(100) surface with an oxygen vacancy, one of the oxygen atoms of the adsorbed CO2 occupies the oxygen vacancy site, and the CO 2 adsorption energy is ?0.31 eV. Water favors dissociative adsorption at the oxygen vacancy site on the defective surface. This process is spontaneous, with a reaction energy of ?0.62 eV. These results indicate that, when water and CO2 are present in the adsorption system simultaneously, water will compete with CO2 for the oxygen vacancy sites and impact CO2 adsorption and conversion negatively. © 2010 American Chemical Society.


Sun X.,Tianjin University of Technology | Ji H.,Tianjin University of Technology | Li X.,Tianjin University of Technology | Cai S.,Tianjin University of Technology | Zheng C.,Tianjin Polytechnic University
Journal of Alloys and Compounds | Year: 2014

Nanoscale α-Fe2O3 with porous structure was synthesized via an open-system nanocasting method. Characterization of the crystal structures, morphologies, surface areas, and pore size distributions of the as-synthesized α-Fe2O3 by wide-angle and small-angle X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen physisorption analysis demonstrated that the nanoscale α-Fe2O3 synthesized in open system had a less crystallinity with average diameter of ∼6.0 nm, higher BET specific surface area of 205.4 m2 g-1, and wider pore size distribution from ∼2.2 nm to 15.7 nm compared with that of the mesoporous α-Fe2O3 synthesized in closed system. The gas-sensing measurement results revealed that the nanoscale α-Fe 2O3 based gas sensor had a much better response to acetone than that of the device prepared from the mesoporous α-Fe 2O3. A possible gas-sensing mechanism based on the α-Fe2O3 samples synthesized with different nanocasting systems was discussed in detail. Wide porous distribution of the nanoscale α-Fe2O3, as well as small particle size and high surface area are effective for gas molecules diffusion and formation of sufficient electron depletion area and result the enhanced sensor response, which suggests that it has great potential for practical applications in diabetes diagnosis. © 2014 Elsevier B.V. All rights reserved.


Wang T.,Tianjin University of Technology | Luo Z.,Tianjin University of Technology | Li C.,Tianjin University of Technology | Gong J.,Tianjin University of Technology
Chemical Society Reviews | Year: 2014

Photoelectrochemical (PEC) water splitting is an attractive approach to generate hydrogen as a clean chemical fuel from solar energy. But there remain many fundamental issues to be solved, including inadequate photon absorption, short carrier diffusion length, surface recombination, vulnerability to photo-corrosion, and unfavorable reaction kinetics. Owing to its self-limiting surface reaction mechanism, atomic layer deposition (ALD) is capable of depositing thin films in a highly controllable manner, which makes it an enabling technique to overcome some of the key challenges confronted by PEC water splitting. This tutorial review describes some unique and representative applications of ALD in fabricating high performance PEC electrodes with various nanostructures, including (i) coating conformal thin films on three-dimensional scaffolds to facilitate the separation and migration of photocarriers and enhance light trapping, as well as realizing controllable doping for bandgap engineering and forming homojunctions for carrier separation; (ii) achieving surface modification through deposition of anti-corrosion layers, surface state passivation layers, and surface catalytic layers; and (iii) identifying the main rate limiting steps with model electrodes with highly defined thickness, composition, and interfacial structure. © the Partner Organisations 2014.


Shi J.,Tianjin University of Technology | Shi J.,Tianjin University | Jiang Y.,Hebei University of Technology | Wang X.,Tianjin University of Technology | And 5 more authors.
Chemical Society Reviews | Year: 2014

Organic-inorganic hybrid capsules, which typically possess a hollow lumen and a hybrid wall, have emerged as a novel and promising class of hybrid materials and have attracted enormous attention. In comparison to polymeric capsules or inorganic capsules, the hybrid capsules combine the intrinsic physical/chemical properties of the organic and inorganic moieties, acquire more degrees of freedom to manipulate multiple interactions, create hierarchical structures and integrate multiple functionalities. Thus, the hybrid capsules exhibit superior mechanical strength (vs. polymeric capsules) and diverse functionalities (vs. inorganic capsules), which may give new opportunities to produce high-performance materials. Much effort has been devoted to exploring innovative and effective methods for the synthesis of hybrid capsules that exhibit desirable performance in target applications. This tutorial review firstly presents a brief description of the capsular structure and hybrid materials in nature, then classifies the hybrid capsules into molecule-hybrid capsules and nano-hybrid capsules based upon the size of the organic and inorganic moieties in the capsule wall, followed by a detailed discussion of the design and synthesis of the hybrid capsules. For each kind of hybrid capsule, the state-of-the-art synthesis methods are described in detail and a critical comment is embedded. The applications of these hybrid capsules in biotechnological areas (biocatalysis, drug delivery, etc.) have also been summarized. Hopefully, this review will offer a perspective and guidelines for the future research and development of hybrid capsules. This journal is © the Partner Organisations 2014.


Kang Y.-R.,Tianjin University of Technology | Li Y.-L.,Tianjin University of Technology | Deng M.-Y.,Tianjin University of Technology
Journal of Materials Chemistry | Year: 2012

Precise unzipping of carbon nanotubes (CNTs) is achieved using flattened carbon nanotubes (F-CNTs) as the starting material and using acid to cut along the folded edges, as these high energy sites are preferentially attacked to yield regular graphene nanoribbons (GNRs). All-bilayer GNRs with narrow uniform width (8-12 nm) and straight edges are fabricated by unzipping flattened double-wall CNTs (F-DWCNTs) using mixed acids of H 2SO 4 and KMnO 4. Transmission electronic microscopy observations confirm the localized and directional unzipping of the F-DWCNTs and the formation of regular bilayer GNRs. The oxidation temperature and acid concentration control the degree of oxidation, the extent of unzipping, and the exfoliation of F-DWCNTs from their bundles. Under certain conditions, assemblies of interconnected GNRs are formed by unzipping F-DWCNT bundles and partial exfoliation. The precise unzipping of flattened CNTs provides a reliable and scalable process for fabricating regular GNRs with controlled structures and morphologies, as demanded for applications that use them as structural, functional and electronic materials. © The Royal Society of Chemistry 2012.


Han F.,Tianjin University of Technology | Lu Y.,Tianjin University of Technology | Zhang Q.,Nankai University | Sun J.,Tianjin University of Technology | And 2 more authors.
Journal of Materials Chemistry | Year: 2012

The electrostatic complexes of double-stranded deoxyribonucleic acid (dsDNA) and a cationic conjugated polyelectrolyte, poly{(4,4′-(1,4- phenylene)bis(2,6-diphenylpyridinium))-co-para-biphenylene ditosylates} (PPT), were investigated by spectral methods. The binding constant of PPT with calf thymus DNA (ctDNA) is estimated to be 9.3 × 10 5 M -1, which was determined by UV-vis spectral titration. Fluorescence emission of PPT in phosphate buffer solutions (5.0 μM) can be drastically quenched to about one-fourth of its original intensity in the presence of a trace amount (0.28 μM) of ctDNA with a large Stern-Volmer constant (K SV = 8.79 × 10 6 M -1). The fluorescence quenching efficiency is related to the target concentration, which allows the quantitative detection of the target sequence in a sample. A linear detection range from 1.5 to 280 nM was obtained under the optimized experimental conditions with a detection limit down to the 10 -9 M range. Furthermore, strong electrostatic attraction may be the main driving force for PPT/ctDNA binding, which was proposed according to the results of circular dichroism and melting transition study of ctDNA in the presence of PPT. This investigation provides an insight into designing a novel conjugated polyelectrolyte for biomolecular sensing. © 2012 The Royal Society of Chemistry.


Hadzibeganovic T.,University of Graz | Xia C.-Y.,Tianjin University of Technology
Knowledge-Based Systems | Year: 2016

Understanding how to enhance cooperation and coordination in distributed, open, and dynamic multiagent systems has been a grand challenge across disciplines. Knowledge employed in such systems is often limited and heuristic in nature such that cooperation-promoting mechanisms based on trust or reputation become largely unreliable. Although recent studies within the context of tag-based systems reported the emergence of stable cooperation in such uncertain environments, they were limited exclusively to only static interaction structures. Consequently, it remains unknown whether and under what conditions tag-based interactions can promote cooperation in dynamic mobile systems. We herein combine the methods of game theory, evolutionary computing, and agent-based simulation to study the emergence of tag-mediated cooperation in a mobile network with resource diversity. In a series of extensive Monte Carlo simulations, we find that tag-based interactions can give rise to high levels of cooperation even in the presence of different types of contingent mobility. Our model reveals that agent migrations within the system and the invasion of new agents from the outside can have similar effects on the evolution of dominant strategies. Interestingly enough, we observe a previously unreported coexistence of conditional and unconditional strategies in our tag-based model with costly migrations. In contrast to earlier studies, we show that this mobility-driven strategy coexistence in our model is not affected by resource limitations or other game-specific factors. Our findings highlight a striking robustness of tag-based cooperation under different mobility regimes, with important consequences for the future design of cooperation-enforcing protocols in large-scale, decentralized, and self-organizing systems such as peer-to-peer or mobile ad-hoc networks. © 2016 Elsevier B.V.


Wang Y.C.,Tianjin University of Technology | Xing R.,Tianjin University of Technology
Advanced Materials Research | Year: 2011

Analyzes the concept and feature of cloud computing, on the basis of this, proposes cloud computing for model of digital library and discusses the security issues, at last proposes a few question should be focused on cloud-based digital library. © (2011) Trans Tech Publications.


Wang Y.C.,Tianjin University of Technology | Chen S.,Tianjin University of Technology
Advanced Materials Research | Year: 2011

This paper analyzes the problems SMEs faced in the informatization construction. Combined with the advantages of SaaS model, we proposed a new model of information management for SMEs based on SaaS software services. But the SaaS model is not without any shortcoming, so this paper also analyzes security risks of SaaS models and put forward the corresponding countermeasures. © (2011) Trans Tech Publications.


Meng Q.,University of Macau | Li Y.,Tianjin University of Technology
IFAC Proceedings Volumes (IFAC-PapersOnline) | Year: 2013

This paper proposes a novel analytical model for flexure-based proportion compliant mechanisms. The displacement and stiffness calculations of such flexure-based compliant mechanisms are formulated based on the principle of virtual work and pseudo rigid body model(PRBM). According to the theory and method, a set of closed-form equations are deduced in this paper, which incorporate the stiffness characteristics of each flexure hinge, together with the other geometric and material properties of the compliant mechanism. Displacement proportion, input stiffness, and output stiffness calculations can simply be performed for any serial compliant mechanism. Corner-filleted and circular flexure hinges that are utilized as connectors in proportion compliant mechanisms in this paper. Two types of flexure-based compliant proportion mechanisms based on the novel analytical model are designed and optimized based on these proposed equations. Finite element analysis results show that these design equations are reliable and easier to be used in the design of such proportion compliant mechanisms. This proposed novel analytical model gives a new viewpoint on the design of flexure-based proportion compliant mechanisms. © 2013 IFAC.


Wang L.,Tianjin University of Technology | Sun S.,Tianjin University of Technology | Xia C.,Tianjin University of Technology
Nonlinear Dynamics | Year: 2012

Finite-time stability problem of multi-agent system in disturbed environment is a question with practical significance. In this paper, a multi-agent system moving with obstacle avoidance is studied. The multi-agent system is expected to form a desired formation in finite time. Finite-time control law for continuous multi-agent system is proposed, which ensures that all the agents can pass the obstacles on their way, and the relative position between two agents reaches a constant value in finite time. Based on some notations and proposition given in the paper, the stability analysis is presented. Finally some simulations are presented to show the effectiveness of the method. © 2011 Springer Science+Business Media B.V.


Zuo D.,Tianjin University of Technology | Hu S.,Tianjin University of Technology | Shen J.,Tianjin University of Technology | Xue Z.,Tianjin University of Technology
Materials and Design | Year: 2014

Copper and aluminum were welded using a continuous Nd:YAG laser, and the influence of the processing parameters on the intermediate layer was investigated. The intermediate layer along the interface was characterized, and the failure mechanism was identified. Four distinct zones with various intermetallic compounds and structures formed in the intermediate layer and determined the corresponding joint strength. Utilizing gradually increasing heat input produced different thicknesses for these four zones. A laser beam power of 1650W and a welding speed of 95mm/s were the optimized parameters. The thickness of the intermetallic compound γ2-Cu9Al4 and the shear-tensile strength of the joint decreased with the increase of welding speed in the weld. The shear-tensile load of the dissimilar metal joint reached 539.52N with the optimized parameters. Fracture during shear-tensile testing occurred in the zone with 20.08-54.65% Cu. It was concluded that eutectic and hypoeutectic structures containing a significant amount of θ-CuAl2 led to a weak joint. The relationship between the mechanical properties and thickness of the different intermediate zones is thoroughly illustrated. © 2014 Elsevier Ltd.


Jie L.,Tianjin University of Technology
IET Conference Publications | Year: 2013

This paper illustrates the urgency of the development of public logistics information platform with strong instantaneity and large amount of information, and the problems should be solved for developing the public logistics information platform. In addition, it puts forward a system structure of the platform, and the key technology of the system are analyzed, as well as the defects of the system design are pointed out.


Jin X.,Tianjin University of Technology | Zhang H.,Tianjin University of Technology | Wang X.,Nankai University | Zhou M.,Nankai University
Electrochimica Acta | Year: 2012

To promote treatment efficiency of organic pollutant, an improved multi-anode contact glow discharge reactor was developed for dye discoloration. This paper investigated how and what extent multi-anode contact glow discharge electrolysis (m-CGDE) could improve the discoloration efficiency of Acid Orange 7 (AO). I-V characteristic of m-CGDE was also studied in details. It was found that the critical voltage of m-CGDE was same to that of single anode. The concentration of H 2O 2 in the anolyte and discoloration rates of AO increased with increasing treatment time and anode number. Furthermore, an improved m-CGDE reactor was designed by replacing platinum wire with stainless steel wire. Under the same conditions, multiple stainless steel anodes greatly enhanced the discoloration of AO. The trace amount of iron ion from stainless steel anodes played Fenton-like reaction important role. © 2011 Elsevier Ltd. All Rights Reserved.


Yan F.,Tianjin University of Technology | Xia S.,Tianjin University of Technology | Wang Q.,Tianjin University of Science and Technology | Ma P.,Tianjin University of Technology
Industrial and Engineering Chemistry Research | Year: 2012

On the basis of the new topological index (TI) proposed in our previous work, a multiple linear regression (MLR) model was developed for predicting the toxicity of ionic liquids (ILs) in Leukemia Rat Cell Line (log EC 50 IPC-81). The TI is derived from atom characters (e.g., atom radius, atom electronegativity, etc.) and atom position in the hydrogen-suppressed molecule structure. Because ILs are composed entirely of cations and anions, the TIs are calculated from cation and anion, respectively. A third TI was also proposed to depict the interaction of anion and cation. The toxicity of 173 ILs, which are based on imidazolium (Im), pyridinium (Py), pyrrolidinium (Pyr), ammonium (Am), phosphonium (Ph), quinolinium (Qu), piperidinium (Pi), and morpholinium (Mo), was calculated by the model. The regression coefficient (R 2) and the overall average absolute error (AAE) are 0.938 and 0.226, respectively. © 2012 American Chemical Society.


Guo Q.,Tianjin University of Technology | Chen S.,Tianjin University of Technology | Liu Y.,Tianjin University of Technology | Wang Y.,Tianjin University of Technology
Chemical Engineering Journal | Year: 2010

The stability of Co-Ce-Mn mixed-oxide catalysts for CO preferential oxidation in H2-rich gases was investigated. The deactivation mechanism was explored using Fourier-transform infrared spectroscopy (FTIR), temperature-programmed desorption (TPD), and reduction and oxidation techniques. The deactivation of the catalysts was observed in reaction gas streams containing CO2. FTIR and CO2-TPD revealed carbonate formation in the deactivated samples. The activity of the deactivated catalysts could be partially regenerated by CO2 desorption and fully regenerated by oxidation treatment which led to a change in the oxidation state of cobalt ions. It is proposed that both carbonate accumulation and the change in the oxidation state of cobalt ions during CO preferential oxidation are responsible for the deactivation of Co-Ce-Mn catalysts. © 2010 Elsevier B.V.


Yan F.,Tianjin University of Technology | Xia S.,Tianjin University of Technology | Wang Q.,Tianjin University of Science and Technology | Yang Z.,Tianjin University of Technology | Ma P.,Tianjin University of Technology
Journal of Chemical Thermodynamics | Year: 2013

A Quantitative Structure Property Relationship (QSPR) model was developed to predict the melting points of ionic liquids (ILs) with diverse classes of cations and anions. The QSPR model was based on the general topological index (TI) proposed in our previous work. The TI was successfully used for the prediction of the decomposition temperature of ILs and the toxicity of ILs in acetylcholine esterase and Leukemia Rat Cell Line. ILs are a class of molten salts which are composed entirely of cations and anions, therefore the descriptors for ILs are generally calculated from cations and anions separately and the interaction between them is neglected. In this study, besides the two sets of TIs generated from cations and anions, a third TI was used to depict the interaction of anions and cations. The QSPR model is on the base of eight kinds of ILs, which are imidazolium, benzimidazolium, pyridinium, pyrrolidinium, ammonium, sulfonium, triazolium and guanidinium. The regression coefficient (R2) and the overall average absolute deviation (AAD) are 0.778 and 7.20%, respectively. © 2013 Elsevier Ltd. All rights reserved.


Han K.,Tianjin University of Technology | Xia S.,Tianjin University of Technology | Ma P.,Tianjin University of Technology | Yan F.,Tianjin University of Technology | Liu T.,Tianjin University of Technology
Journal of Chemical Thermodynamics | Year: 2013

A set of high-pressure view apparatus was designed for determining the critical properties of chemicals. In order to check the reliability of the apparatus, the critical temperatures (Tc) and critical pressures (Pc) of pure n-heptane, cyclohexane, methanol, ethanol, 1-propanol, methyl tert-butyl ether (MTBE), and binary mixture n-hexane + ethanol were measured. The experimental data were in good agreement with the literature data, which proves the reliability of the apparatus used in the work. The critical temperatures and critical pressures of five binary mixtures containing gasoline additive (MTBE + n-heptane, MTBE + cyclohexane, MTBE + methanol, MTBE + ethanol, MTBE + 1-propanol) were measured using the high-pressure view cell with visual observation. The critical temperatures and critical pressures for the five binary mixtures were all reported for the first time. In addition, the critical temperatures and critical pressures of the binary mixture n-heptane + cyclohexane (two of main components in gasoline) were also measured. All the critical lines for the mixtures studied are continuous which connect the critical points of the two pure components, indicating their phase diagrams belong to type I proposed by Scott and van Konynenburg. The critical points of these systems were calculated by the Peng-Robinson equation of state with the Wong-Sandler mixing rule. This model could calculate the critical properties of the mixtures well with the binary interaction parameter kij obtained by fitting the experimental critical data. And the experimental data were all fitted well with Redlich-Kister equation. The maximum average absolute deviations were 0.06% for critical temperatures and 0.35% for critical pressures. © 2013 Elsevier Ltd. All rights reserved.


Wu X.-j.,Tianjin University of Technology | Zhang A.-l.,Tianjin University of Technology
Optoelectronics Letters | Year: 2012

In this paper, we propose a method to realize microwave photonic filter (MPF) with complex coefficient, whose central frequency f 0 and 3 dB bandwidth are tunable. The complex coefficient is realized by multi-wavelength optical source and stimulated Brillouin scattering (SBS). The central frequency of the filter is tuned by adjusting the phase shift caused by SBS without changing its frequency response. The frequency selectivity of filter can be improved through increasing the bandwidth of broadband optical source (BOS) or decreasing wavelength separation to increase the taps of MPF. The mainlobeto-sidelobe suppression ratio (MSSR) of the filter is affected by the weight of each tap. When the length of fiber is 0. 5544 m in birefringence fiber loop mirror (FLM), the MSSR is improved by 18. 55 dB compared with that without the weight controlling. © 2012 Tianjin University of Technology and Springer-Verlag Berlin Heidelberg.


Li W.,Tianjin University | Li W.,Tianjin University of Technology | Chen M.,Tianjin University of Technology
Applied Surface Science | Year: 2014

In this study, pure Cu nanoparticles (NPs) have been successfully synthesized and the Cu nano-ink was prepared for direct writing on photo paper using a roller pen. The tri-sodium citrate was used as initial reducing-cum-surfactant agent followed by hydrazine as a second massive reducing agent and cetyltrimethylammonium bromide (CTAB) as extra surfactant agent. From the XRD, TEM, and HR-TEM analyses, the synthesized particles are confirmed to be Cu in spherical shape with sizes range of 2.5 ± 1.0 nm. By analyzing the FT-IR spectroscopy and TGA curves, it was found that the obtained particles capped with tri-sodium citrate and CTAB layers are stable to oxidation up to the temperature 228 C. The reduced size and enhanced air-stability of the Cu NPs result in an improved particle density upon sintering, which is mainly responsible for the increased conductivity of the Cu patterns. The resistivity of Cu patterns sintered in Ar at 160 C for 2 h is 7.2 ± 0.6 μΩ cm, which is 4.40 times the bulk Cu resistivity. The drawn Cu lines exhibited excellent integrity and good conductivity, which were experimentally tested. Moreover, a Cu electrode and a sample RFID antenna were successfully made. © 2013 Elsevier B.V.


Yue H.,Tianjin University of Technology | Ma X.,Tianjin University of Technology | Gong J.,Tianjin University of Technology
Accounts of Chemical Research | Year: 2014

ConspectusEthanol is an attractive end product and a versatile feedstock because a widespread market exists for its commercial use as a fuel additive or a potential substitute for gasoline. Currently, ethanol is produced primarily by fermentation of biomass-derived sugars, particularly those containing six carbons, but coproducts 5-carbon sugars and lignin remain unusable. Another major process for commercial production of ethanol is hydration of ethylene over solid acidic catalysts, yet not sustainable considering the depletion of fossil fuels. Catalytic conversion of synthetic gas (CO + H2) could produce ethanol in large quantities. However, the direct catalytic conversion of synthetic gas to ethanol remains challenging, and no commercial process exists as of today although the research has been ongoing for the past 90 years, since such the process suffers from low yield and poor selectivity due to slow kinetics of the initial C-C bond formation and fast chain growth of the C 2 intermediates.This Account describes recent developments in an alternative approach for the synthesis of ethanol via synthetic gas. This process is an integrated technology consisting of the coupling of CO with methanol to form dimethyl oxalate and the subsequent hydrogenation to yield ethanol. The byproduct of the second step (methanol) can be separated and used in circulation as the feedstock for the coupling step. The coupling reaction of carbon monoxide for producing dimethyl oxalate takes place under moderate reaction conditions with high selectivity (∼95%), which ideally leads to a self-closing, nonwaste, catalytic cycling process. This Account also summarizes the progress on the development of copper-based catalysts for the hydrogenation reaction with remarkable efficiencies and stability. The unique lamellar structure and the cooperative effect between surface Cu0 and Cu + species are responsible for the activity of the catalyst with high yield of ethanol (∼91%). The understanding of nature of valence states of Cu could also guide the rational design of Cu-based catalysts for other similar reactions, particularly for hydrogenation catalytic systems. In addition, by regulating the reaction condition and the surface structure of the catalysts, the products in the hydrogenation steps, such as ethanol, methyl glycolate, and ethylene glycol, could be tuned efficiently. This synthetic approach enables a more sustainable ethanol, methyl glycolate, and ethylene glycol synthesis in industry and greatly reduces the dependence on petroleum resources and the emission of the greenhouse gas. © 2014 American Chemical Society.


Zhang A.,Tianjin University of Technology | Zhang S.,Tianjin University of Technology
IEEE Sensors Journal | Year: 2016

In this paper, an optical fiber interferometric sensor with improved phase generated carrier (PGC) demodulation algorithm is proposed to eliminate the influence of light intensity disturbance (LID). Performance of sensor using proposed algorithm is analyzed and compared with sensor using differential-cross-multiplying (PGC-DCM) algorithm and PGC Arctangent (PGC-Arctan) algorithm, respectively. Experimental results show that not only LID distortion, but also harmonic distortion is well suppressed by the improved PGC algorithm. In experiment, the signal to noise and distortion (SINAD) ratio of sensor using proposed algorithm achieve a gain of 16.4 dB and 10.8 dB over sensor using PGC-DCM and PGC-Arctan algorithm, respectively. © 2016 IEEE.


Hao R.S.,Tianjin University of Technology
Applied Mechanics and Materials | Year: 2013

In this paper, the second order recurrent neural network is adopted to study the inverse kinematics problem of three degree-of-freedom planar redundant manipulators. The Simulation results show that the network can effectively solve the inverse kinematics problem of redundant manipulators, and it reaches to good precision of solution and solving speed. © (2013) Trans Tech Publications, Switzerland.


Wu D.Y.,Tianjin University of Technology
Applied Mechanics and Materials | Year: 2013

Electromagnetism based detection has advanced rapidly in recent years because of its characteristics of non-contact and non-invasion nature. An electromagnetic measurement system for monitoring the crack of conductivity material was presented in this paper. The system consists of signal source module, measuring module and demodulation module. In order to evaluate the system performance, some prime experimental work was undertaken, the results showed the feasibility of the system. © (2013) Trans Tech Publications, Switzerland.


Chen Z.,Tianjin University of Technology | Chen W.,Tianjin University of Technology | Tong T.,Tianjin University of Technology | Zeng A.,Tianjin University of Technology
Journal of Molecular Catalysis A: Chemical | Year: 2015

The continuous liquid phase Friedel-Crafts acylation of toluene (T) by acetic anhydride (AA) over HBEA zeolite was carried out in a fixed bed reactor, with acetic acid (AC) as a solvent. 4-Methylacetophenone (4-MAP) was selectively formed in the initial reaction stage. However, a rapid catalyst deactivation occurred with a sharp decrease of the conversion of acetic anhydride, and this was mainly caused by 4-MAP and heavy compounds ('coke') existing in the zeolite pore, which poisoned the active sites of the catalyst. The use of excess toluene and moderate acetic acid enhanced catalyst activity and stability to some extent as it limited both the retention of 4-MAP and the formation of 'coke'. Moreover, a considerable reduction of Broensted acid sites after deactivation revealed that the toluene acylation is primarily a Broensted acid catalyzed reaction. © 2014 Elsevier B.V. All rights reserved.


Pan M.,University of Texas at Austin | Gong J.,Tianjin University of Technology | Dong G.,University of Texas at Austin | Mullins C.B.,University of Texas at Austin
Accounts of Chemical Research | Year: 2014

Historically, scientists have considered gold an inert catalyst constituent. However, in recent decades, chemists have discovered that nanoscale gold shows exceptional activity for many chemical reactions. They have investigated model gold surfaces in order to obtain fundamental understanding of catalytic properties. In this Account, we present our current understanding of oxidation and hydrogenation reactions on the Au(111) single crystal as a planar representative of gold catalysts, revealing the interesting surface chemistry of gold.We begin by comparing two inverse reactions, alcohol oxidation and aldehyde hydrogenation, on a Au(111) surface. Beyond the expected different chemistry, we observe intriguing similarities since the same surface is employed. First, both molecular oxygen and hydrogen have high barriers to dissociation on Au(111), and frequently chemists study reactions here by using atomic O and H to populate the surfaces. Recombinative desorption features of oxygen and hydrogen are apparent at ∼500 and ∼110 K, lower than other transition metals. These results indicate that oxygen and hydrogen have low desorption activation energies and weakly chemisorb on the surface, likely leading to selective reactions. On the oxygen-precovered Au(111) surface, alcohols are selectively oxidized to aldehydes. Similarly, weakly bound hydrogen atoms on Au(111) also show chemoselective reactivity for hydrogenation of propionaldehyde and acetone.The second similarity is that the gold surface activates self-coupling of alcohol or aldehyde with oxygen or hydrogen, resulting in the formation of esters and ethers, respectively, in alcohol oxidation and aldehyde hydrogenation. During these two reactions, both alkoxy groups and alcohol-like species show up as intermediates, which likely play a key role in the formation of coupling products. In addition, the cross coupling reaction between alcohol and aldehyde occurs on both O- and H-modified surfaces, yielding the production of esters and ethers, respectively. Thus, we can tune the molecular structure of both esters and ethers by selecting the corresponding aldehyde and alcohol for the coupling reaction.These studies indicate that gold is a versatile active catalyst for various reactions, including oxidation and hydrogenation transformations. Despite the very different chemistry for these two reactions, we can establish an intrinsic relationship due to the distinct catalytic properties of gold. It can show activity for selective reactions on both O- and H-covered Au(111) and further induce the coupling reaction between surface reactants and adsorbed O/H to produce esters and ethers. This comparison demonstrates the unique surface chemistry of gold and enhances understanding of its catalytic properties. © 2013 American Chemical Society.


Meng Q.,Tianjin University of Technology | Wang T.,Tianjin University of Technology | Liu E.,Tianjin University | Ma X.,Tianjin University of Technology | And 3 more authors.
Physical Chemistry Chemical Physics | Year: 2013

This paper describes an investigation into the general trend in electronic properties of anatase TiO2 photocatalysts co-doped with transition metals and nitrogen employing first-principles density functional theory. Fourteen different transition metals (M), including Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, and Cd, have been considered. The characteristic band structures of the co-doping systems involving the transition metal series are presented. Our results indicate that the absorption edges of TiO2 are shifted to the visible-light region upon introduction of dopants, due to the reduced conduction band minimum (CBM) and the formation of impurity energy levels (IELs) in the band gap. These IELs are primarily formed from (a) the anti-bonding orbitals of the M-O (M indicates the doped transition metal) bonds, (b) the unsaturated nonbonding d orbitals of the doped transition metal (mainly dxy, dyz, and dxz), and (c) the Ti-O bonding/Ti-N anti-bonding orbitals of the bond next to the doped transition metal. When the valence d electrons of the doped metal are between 3 and 7, all three types of IELs appear in the band gap of the (M, N) co-doped systems. For systems doped with a metal of more than 7 valence electrons, only types (a) and (c) of IELs as well as the unoccupied pz state of N are observed. Based on our analysis, we propose that the co-doping systems such as (V, N), (Cr, N), and (Mn, N), which have the IELs with a significant bandwidth, are of great potential as candidates for photovoltaic applications in the visible light range. © 2013 the Owner Societies.


Meng X.-K.,Tianjin University of Technology | Xia C.-Y.,Tianjin University of Technology | Gao Z.-K.,Tianjin University | Wang L.,Tianjin University of Technology | Sun S.-W.,Tianjin University of Technology
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2015

We present an improved spatial prisoner's dilemma game model which simultaneously considers the individual diversity and increasing neighborhood size on two interdependent lattices. By dividing the players into influential and non-influential ones, we can discuss the impact of individual diversity on the cooperative behaviors. Meanwhile, we implement the utility interdependency by integrating the payoff correlations between two lattices. Extensive simulations indicate that the optimal density of influential players exists for the cooperation to be promoted, and can be further facilitated through the utility coupling. Current results are beneficial to understanding the origin of cooperation among selfish agents among realistic scenarios. © 2015 Elsevier B.V. All rights reserved.


Ding L.,Tianjin University of Technology | Hu S.,Tianjin University of Technology
Surface and Coatings Technology | Year: 2015

Co-based composite coatings with different nano-CeO2 contents were successfully prepared on SPHC steel by laser cladding. The effect of nano-CeO2 on microstructure and properties of Co-based coatings were systematically investigated. The phase construction and microstructure of the coatings were characterized by optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray spectrometer (EDS). The hardness and wear resistance of the coatings were evaluated by HV-1000 hardness tester and MM-200 type wear tester at room temperature as well as applied multivariate statistical analysis method. The results indicated that Co-based coatings with nano-CeO2 exhibited an excellent appearance quality, another fine microstructure and new phase Ce2Ni7 appeared. The microhardness and wear resistance of coatings first improved and then decreased with increasing nano-CeO2 content in the coatings and the improvement in microhardness and the reduction in total loss were respectively 35.3% and 55.0%, at 1.5wt.% nano-CeO2, the wear mechanism was abrasive wear. The great effect of nano-CeO2 addition on microhardness and wear resistance of coatings were consistent with the calculation results of applied multivariate statistical analysis. Thus, it is concluded that adding nano-CeO2 is an effective and attainable way to improve the wear resistance of Co-based coatings. © 2015 Elsevier B.V..


Tang S.,Tianjin University of Technology | Wang L.,Tianjin University of Technology | Zhang Y.,Tianjin University of Technology | Li S.,Tianjin University of Technology | And 2 more authors.
Fuel Processing Technology | Year: 2012

A magnetic composite solid catalyst was prepared by loading calcium aluminate onto Fe 3O 4 nanoparticles via a chemical synthesis method. The optimum conditions for the catalyst preparation were investigated. The influences of the molar ratio of Ca to Fe, calcining temperature, calcining time on the catalytic performance were studied. The catalyst with the highest activity was obtained when the molar ratio of Ca to Fe was 5:1; calcining temperature was 600 °C and calcining time was 6 h. The catalyst was characterized by thermogravimetric analyses (TGA), X-ray diffraction (XRD), scanning electronic microscope (SEM), Brunauer-Emmett-Teller method (BET) and vibrating sample magnetometer (VSM). Furthermore, the magnetic composite solid catalyst showed high catalytic activity for transesterification reaction for preparing biodiesel and the biodiesel yield reached 98.71% under the optimum conditions. The activity and recovery rate of this magnetic composite catalyst can be well maintained after 5 cycles of catalysis. This catalyst showed magnetism and can be easily separated magnetically. Both the catalytic activity and the recovery rate of the magnetic composite solid catalyst were much higher than those of pure calcium aluminate catalyst. © 2011 Elsevier B.V. All rights reserved.


Liu G.,Tianjin University of Technology | Zhao G.,Tianjin University of Technology | Meng F.,Tianjin University of Technology | Qu S.,Tianjin University of Technology | And 2 more authors.
Energy and Fuels | Year: 2012

Wall-coated HZSM-5 with micro- and nanoscale crystal sizes were prepared and coated to the inner surface of SS304 stainless-steel tubes using washcoating methods. It was found that nanoscale HZSM-5 zeolite slurry has different rheological properties, washcoat loadings, and adhesions with microscale HZSM-5. Catalytic activities of the prepared micro- and nanoscale HZSM-5 zeolite coatings were studied using catalytic cracking of supercritical-phase n-dodecane (550 °C and 4 MPa), indicating that catalytic cracking activity and stability were remarkably improved more than 1 time by nanoscale HZSM-5 coatings compared to microscale HZSM-5 coatings. Acid and pore structure characterization showed that the better performance of nanoscale HZSM-5 coating may be attributed to the shorter diffusion length of the micropore, the higher diffusion rate of supercritical n-dodecane in the intracrystal mesopore, and the special acid nature of nanoscale HZSM-5 coatings. © 2011 American Chemical Society.


Wei F.,Tianjin University of Technology | Lu Y.,Tianjin University of Technology | He S.,Tianjin University of Technology | Zhao L.,Tianjin University of Technology | And 2 more authors.
Analytical Methods | Year: 2012

A novel strategy to design a fluorescent chemosensor for OCl - which can be used over a pH span of 6-11 by integrating the reactive phenylhydrazo group within rhodamine 6G has been achieved. Upon the reaction with OCl -, a significant fluorescence enhancement was triggered with a detection limit down to the 10 -9 M range. © 2012 The Royal Society of Chemistry.


Muroya Y.,Waseda University | Enatsu Y.,Waseda University | Li H.,Tianjin University of Technology
International Journal of Computer Mathematics | Year: 2014

We propose a delayed SIRS computer virus propagation model. Applying monotone iterative techniques and Lyapunov functional techniques, we establish sufficient conditions for the global asymptotic stability of both virus-free and virus equilibria of the model. © 2013 Taylor & Francis.


Xu J.,Tianjin University of Technology
Revista Tecnica de la Facultad de Ingenieria Universidad del Zulia | Year: 2016

When application in time series forecasting, the standard SVM (support vector machine) algorithm has some defects, such as low accuracy in preferences and weak performance of anti-noise. In this paper, a time series forecasting model is proposed based on SVM with error correction of parameter selection. First, the historical data is for standardizing treatment to remove the smaller noise of signal within the prescribed scope. Then with space density clustering method reduces the influence of the noise data. And then the simulated annealing algorithm (SA) is introduced into the parameter selection of support vector machines, to modify the error of SVM algorithm. Simulation results show that the mean square error of the proposed SVM algorithm is smaller, greatly reduces the error of the parameter selection. And compared with standard SVM algorithm, forecasting Jingdong has significant improvement in the application of the short-term power load.


Gao D.,Tianjin University of Technology | Guo R.,Tianjin University of Technology
Journal of Alloys and Compounds | Year: 2010

The influences of CuO doping on the sintering behavior, phase formation and electrochemical properties of yttrium-doped barium zirconate were investigated in this study. Unmodified yttrium-doped barium zirconate was difficult to densify. 1-2 mol% CuO can markedly enhance the sinterability of yttrium-doped barium zirconate. No CuO was detected in the CuO-modified samples, which suggested that the CuO might dissolve into the perovskite lattice structure. The electrical conductivity of 1 mol% CuO-modified yttrium-doped barium zirconate was close to that of unmodified one at the testing temperatures ranging from 500 °C to 800 °C in moisture-saturated hydrogen. Electromotive force measurements under fuel cell conditions revealed that the ionic transport number of CuO-modified yttrium-doped barium zirconate was large enough to apply the material as electrolyte in solid oxide fuel cell. © 2009 Elsevier B.V. All rights reserved.


Liu M.-L.,Tianjin University of Technology | Qu Y.-F.,Tianjin University of Technology | Yang D.-A.,Tianjin University of Technology
Journal of Alloys and Compounds | Year: 2010

Lead-free positive temperature coefficient of resistivity ceramics based on 0.999BaTiO3-0.001(Bi0.5Na0.5)TiO3 solid solution were fabricated by the conventional ceramic technique, while Bi2O3 was doped directly or after pre-calcining, in the molar ratio of Bi2O3:Na2CO3:TiO 2 (G) = 1:1:4, 1.005:1:4, 1.01:1:4, and 1.015:1:4, respectively. There are two synthesizing route, i.e. the materials with G = 1.005:1:4 were pre-calcined at 780 °C firstly and then doped into the basic materials and the materials were directly doped by G = 1.01:1:4 into the starting materials with another holding process at 850 °C for 30 min during co-calcining with BaTiO3, both of which could obtain samples with the maximum Curie temperature about 144 °C. The latter also possessed comparatively lower room temperature resistance about 22.0 Ω. A further study was deserved to carry out in an attempt to obtain ceramics with higher Curie temperature via more Bi2O3-doping. © 2010 Elsevier B.V. All rights reserved.


Ruidong W.,Tianjin University of Technology
Acta Mathematica Scientia | Year: 2010

In this article, we prove that an into 1-Lipschitz mapping from the unit sphere of a Hilbert space to the unit sphere of an arbitrary normed space, which under some conditions, can be extended to be a linear isometry on the whole space. © 2010 Wuhan Institute of Physics and Mathematics.


Yu B.,Tianjin University of Technology | Wang C.,Tianjin University of Technology | Chen M.,Tianjin University of Technology | Zheng J.,Tianjin University of Technology | Qi J.,Tianjin University of Technology
Fuel Processing Technology | Year: 2012

The traditional techniques for preparing spinnable pitch from coal tar pitch are air blowing or thermal treatment. A new method to produce isotropic spinnable pitch has been developed. In this method, a commercial almost free of quinoline insoluble (almost QI-free) coal tar pitch was firstly air blown in the temperature range of 280 to 320 °C. Air blowing increases the softening point of the pitch without destroying its spinnability. Next, a thermal treatment between 350 and 380 °C was applied and this increased the softening point to 280 °C. The effects of processing parameters such as treatment time and temperature for air blowing and thermal treatment on the characteristics of the spinnable pitch were studied. The spinnable pitch obtained by the two-step technique exhibited a high softening point (280 °C), a high coking value (82%). The green fibers spun from the pitch, showed uniform diameters (19 ± 1 μm) with smooth and homogeneous surfaces. The green fibers were then stabilized at 320 °C for 1 h and further carbonized at 1000 °C for 1 h in nitrogen. The obtained carbon fibers also had smooth surfaces and homogeneous diameters (17 ± 1 μm). © 2012 Elsevier B.V.


Song X.-J.,Tianjin University of Technology
Applied Mechanics and Materials | Year: 2013

This design in certain food products factory for intelligent control of wastewater treatment processes, monitoring and management. The system consists of lower and upper computer. The lower-level computer consists of PLC and the intelligent instruments. The intelligent instruments can process control the frequency conversion timing machine, opening valve and so on. The PLC can receive all data from the controlling instruments of the upper-level one. Eventually MCGS configuration software, real-time monitoring of wastewater treatment processes and changes of analog. So as to realize combination of automatic and manual control, field and remote control with the combination of purpose. © (2013) Trans Tech Publications, Switzerland.


Zhao J.,Tianjin University of Technology | Guo H.,China University of Geosciences
Applied Mechanics and Materials | Year: 2013

The effects of arsenic uptake by Pteris vittata L. and Polystichum craspedosorum were examined. Pteris vittata L. were exposed hydroponically to 4.8 mg/L As(V) for 16 d and 4.05 mg/L As(V) for 24 h. Arsenic concentration in solution respectively decreased to 1.61 mg/L and 3.86mg/L. TF after 24 h was 0.81(<1) while TF after 16 d was 2.83 (>1). Polystichum craspedosorum were exposed hydroponically to 3.26 mg/L As(V) for 20 days. As concentration decreased to 2.83mg/L after 16d and then increased slowly in the later four days. As contents in roots and fronds of Polystichum craspedosorum were 147 mg/kg and 90mg/kg. The results indicated that Polystichum craspedosorum was not good candidate for removal As(V) from water compared with Pteris vittata L. © (2013) Trans Tech Publications, Switzerland.


Kong K.F.,University of Macau | Li Y.,Tianjin University of Technology
Chinese Control Conference, CCC | Year: 2013

In this paper, two kinds of methods are used to control the mobile manipulator in terms of voice signal control approach and visual signal control approach. In voice signal control approach, the mobile manipulator can perform some actions according to the operator's speaking voice input through a microphone. For example, the robot can be commanded to go forward or backward in specified distance, turn left or right with specified angle, even can follow up '8' shape trajectory and catch a ball. In visual approach, the mobile robot can accomplish some actions according to the operator's gestures of two hands using Kinect sensor information. It gets the depth image of two hands in spatial coordinates and calculates the relative distance of them to take some actions by an onboard computer. An embedded single board computer is installed in mobile robot Pioneer2 DX for enhancing remote control and running program's ability. © 2013 TCCT, CAA.


Wang J.,Tianjin University of Technology | Lu Y.,Tianjin University of Technology
Materials and Design | Year: 2016

Synthesis of non-spherical silica micro-/nano-particles is an essential and interesting research topic for their unique property and potential application in biomedicine. Herein, an new asymmetrical flower-like silica with size ranging from about 200 nm to 600 nm was prepared by simply changing the reaction temperature in the water/polyvinylpyrrolidone (PVP)/n-pentanol system. Further, the effect of reaction conditions including temperature, concentration of sodium citrate and average molecular-weight of PVP on the morphology of the resultant silica was studied in detail. The growth mechanism of flower-like silica is proposed based on SEM images with different reaction times. This work provides a facile method to fabricate anisotropic silica which may find its application in drug delivery. © 2016 Elsevier Ltd


Xi Z.,Tianjin University of Technology | Li A.,Tianjin University of Technology
Process Safety and Environmental Protection | Year: 2016

For retarding self-heating of coal, a technique is described by applying a blend of thermoplastic and coal powder (TCP) in a foam carrier. The experimental study includes the behavior, microstructure and evolution of the foam, and the properties of the thermoplastic powder (TP) for inhibiting the spontaneous combustion of coal. It was found that increased TCP concentrations led to decreased foamability, with the detrimental effect on foamability levelling of at concentrations above 30 wt.%. The low fusing temperature and high heat of fusion of the TP absorbed the heat generated by the self-heating coal at low temperatures. The liquid fused TP sealed gaps and cracks in the coal dust from oxygen entry. Infrared spectra showed that the TP suppressed alkyl and hydroxyl functional groups in the coal powder (CP) at higher temperatures. It was concluded that TP retarded self-heating in coal, and that the combined thermoplastic and coal powder in a foam carrier has the potential to prevent and control the spontaneous combustion of coal. © 2016 Institution of Chemical Engineers


Zhao K.,Harbin Institute of Technology | Li Y.,Tianjin University of Technology
Chinese Control Conference, CCC | Year: 2013

This paper addresses the problem of implementing Rapidly-exploring Random Tree (RRT) in a large-scale indoor environment. The details of environment modeling based on real indoor metric map are described, thereafter a novel method is used to construct a topological map. A series of tests indicate that RRT planner using this topological map can efficiently search for appropriate path by reducing the search space size. © 2013 TCCT, CAA.


Xue J.,Tianjin University of Technology | Wang X.,Tianjin University of Technology | Qi G.,General Motors | Wang J.,Tianjin University of Technology | And 3 more authors.
Journal of Catalysis | Year: 2013

To investigate the active Cu sites in the selective catalytic reduction of NO by NH3 (NH3 SCR) over Cu/SAPO-34 catalysts, a series of samples containing different Cu loadings has been prepared by an ion-exchange process. A combination of H2 TPR and EPR techniques was applied to identify and quantify the isolated Cu2+ sites. The trend of the isolated Cu2+ ions in the samples estimated by EPR is similar to that from TPR results and was found to be proportional to the NH3 SCR reaction rates. The turnover frequency (TOF) calculated based on the number of isolated Cu2+ ions on samples with varying Cu loadings showed a constant value at the same temperature. Thus, we conclude that the isolated Cu2+ species associated with the six-ring window and displaced into the ellipsoidal cavity of SAPO-34 (Site (I)) are the active sites for the NH3 SCR reaction in the temperature range 100-200 °C. © 2012 Elsevier Inc. All rights reserved.


Yang L.,Tianjin University of Technology | Seshan K.,University of Twente | Li Y.,Tianjin University of Technology
Catalysis Communications | Year: 2013

The production of chemicals from lignin and lignin depolymerisation products is a promising alternative route to replace fossil fuels. Transetherification of guaiacol, a lignin derived model compound, to o-ethoxyphenol with γ-Al2O3 as the catalyst in supercritical ethanol has been investigated. The best reaction condition is 280°C for 3 h, giving a yield of 42% with a selectivity of 86%. A reaction pathway is also proposed. Besides, this work provides an example for producing a longer chain ether from a short chain ether. © 2012 Elsevier B.V.


Zhang Q.,Tianjin University of Technology
Numerical Functional Analysis and Optimization | Year: 2016

Stability is an expected property for refinable vectors, which is widely considered in the study of refinement equations. There are two types of stability for refinable vectors. One is the ordinary-stability, another is the vector-stability. The ordinary-stabilityconsiders the stability of entries of refinable vectors, but the vector-stability considers the stability of refinable vectors when they are considered as elements of super-Hilbert spaces. In this article, we give a necessary and sufficient condition for refinable vectors to be vector-stable. Our results improve on some known ones. © 2016, Taylor & Francis.


Gao Z.-K.,Tianjin University | Yang Y.-X.,Tianjin University | Fang P.-C.,Tianjin University | Zou Y.,East China Normal University | And 2 more authors.
EPL | Year: 2015

The multiscale phenomenon widely exists in nonlinear complex systems. One efficient way to characterize complex systems is to measure time series and then extract information from the measurements. We propose a reliable method for constructing a multiscale complex network from multivariate time series. In particular, for a given multivariate time series, we first perform a coarse-grained operation to define temporal scales and then reconstruct the multivariate phase-space for each scale to infer multiscale complex networks. In addition, we develop a novel clustering coefficient entropy to assess the derived multiscale complex networks, aiming to characterize the coupled dynamical characteristics underlying multivariate time series. We apply our proposed approach to the analysis of multivariate time series measured from gas-liquid two-phase flow experiments. The results yield novel insights into the inherent coupled flow behavior underlying a realistic multiphase flow system. Bridging multiscale analysis and complex network provides a fascinating methodology for probing multiscale complex behavior underlying complex systems. © Copyright EPLA, 2015.


Shi L.,Tianjin University of Technology
Communications in Computer and Information Science | Year: 2012

SME plays an irreplaceable role in the national economy and plays a huge role in China's economic development. However, SME faces many difficulties because of its characteristics. Especially financial difficulty has become the biggest bottleneck. The article indicates from internal and external factors that information asymmetry and higher costs owing to its own governance structure are the main reason of financing difficulties of SME, and then put forward the corresponding solutions. © 2012 Springer-Verlag Berlin Heidelberg.


Liu Y.,Tianjin University | Xin F.,Tianjin University | Wang F.,Tianjin University | Luo S.,Tianjin University | Yin X.,Tianjin University of Technology
Journal of Alloys and Compounds | Year: 2010

A series of Bi2O3-TiO2 composite photocatalysts were prepared with a facile nonaqueous sol-gel method through varying the Bi-Ti atomic ratio and calcination temperature. The catalyst structures had been extensively characterized by using X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy (UV-vis DRS). The characterization results revealed that all of the Bi2O3-TiO2 composites exhibited smaller crystallite size, higher thermal stability and stronger absorbance in visible light range than pure TiO2. The photocatalytic activities of as-prepared catalysts were evaluated by the degradation of methyl orange (MO). The results showed that the Bi-Ti atomic ratio of 0.0175 was an optimum in the photocatalytic activities under visible light irradiation and the calcination temperature affected both the physicochemical properties and photocatalytic activities of the catalysts. XPS and XRD were further used to characterize the stability of the photocatalyst, which maintained a high activity without obvious deactivation after five recycles of the degradation. © 2010 Elsevier B.V. All rights reserved.


Liu M.-l.,Tianjin University of Technology | Yang D.-a.,Tianjin University of Technology | Qu Y.-f.,Tianjin University of Technology
Journal of Alloys and Compounds | Year: 2010

Extensive studies on Bi2O3 doping methods and contents of (1 - x)BaTiO3-x(Bi0.5Na0.5)TiO3 ((1 - x)BT-xBNT, x = 0.01, 0.03, 0.05, 0.10, 0.15, 0.25 mol) ceramics have been investigated. The samples were fabricated by the conventional ceramic process, while Bi2O3, Na2CO3, and TiO2 were doped in the molar ratio of 1:1:4 and 1.005:1:4 (Bi-excess), respectively, to create (Bi0.5Na0.5)TiO3. The temperature dependence dielectric constant and loss revealed that (1 - x)BT-xBNT ceramics had a typical relaxor behavior and diffuse phase transition characteristics and the degree of ferroelectric relaxation behavior was enhanced with the increase of BNT-dopant concentration. In addition, all the tan δ-T curves showed a low and broad platform under 100 °C. The room temperature permittivity decreased sharply at x ≤ 0.05 mol and then they varied slowly with x increasing. The temperature of permittivity maximum (Tm) could be improved when x ≤ 0.15 mol and this tendency was more apparent when doped with excess Bi2O3. © 2010 Elsevier B.V. All rights reserved.


Li Y.,Texas A&M University-Commerce | Li Y.,Tianjin University of Technology | Jang B.W.L.,Texas A&M University-Commerce
Applied Catalysis A: General | Year: 2011

Non-thermal RF plasma modification has been applied to Pd/TiO2 catalysts for selective hydrogenation of acetylene in the presence of ethylene. High ethylene selectivity and high acetylene conversion were obtained over the plasma-treated catalysts. To understand the plasma effect, the catalysts were characterized by differential scanning calorimetry in hydrogen (H 2-DSC), pulse H2 chemisorption, X-ray photoelectron spectroscopy (XPS), Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) with CO and temperature-programmed desorption with ethylene (C 2H4-TPD). XPS and H2-DSC results confirmed that supported Pd precursors could be effectively reduced to the metallic state during the room temperature plasma treatment. Plasma treatments also enhanced the surface active sites of Pd/TiO2 catalysts and improved the dispersion of Pd metal particles. In addition, DRIFTS and C2H 4-TPD results indicated that plasma treatments could induce strong metal-support interaction with lower reduction temperature (200 °C), which lead to an enhanced catalytic performance on selective hydrogenation of acetylene. It demonstrates that the RF non-thermal plasma treatment is an effective way to manipulate surface properties and the interaction between metals and supports of supported Pd catalysts for selective hydrogenation. © 2010 Elsevier B.V. All rights reserved.


Cui Y.,Tianjin University of Technology | Zhao X.,Tianjin University of Technology | Guo R.,Tianjin University of Technology
Journal of Alloys and Compounds | Year: 2010

CuO and carbon co-coated LiFePO4 composites were prepared by a chemical precipitation method. The incomplete carbon network is repaired by the nano-sized CuO as proved by high-resolution transmission electron microscopy. The effects of the co-coating of CuO and carbon on the cycle performance of LiFePO4 cathode are investigated. It is found that the co-coating reduces the capacity fading especially at high charge/discharge rates. Results of the impedance spectroscopy and cyclic voltammogram measurements indicate that the interfacial resistances decrease remarkably and the polarization of the cathode is reduced significantly. This can be mainly attributed to the improvement of electrochemical kinetics by the co-coating with nano-sized CuO and carbon. © 2009 Elsevier B.V. All rights reserved.


Miao L.,Tianjin University of Technology | Cai S.,Tianjin University of Technology | Xiao Z.,Tianjin University of Technology
Journal of Alloys and Compounds | Year: 2010

Nanostructured ZnO thin films were electrophoretically deposited from ZnO colloidal suspensions. The microstructural properties of the nanoparticles were examined through XRD and TEM techniques. ZnO nanocrystallites in a hexagonal wurtzite phase with the size in the range of 4-8 nm were synthesized through colloid synthesis. The deposition parameters were studied with the aim of producing a crack-free, dense and smooth ZnO thin film. The deposit weight can be controlled by adjusting several deposition parameters. The average optical transmittance of the obtained ZnO film was higher than 90% with light wavelengths from 450 to 700 nm. © 2009 Elsevier B.V. All rights reserved.


Zhang W.,Tianjin University of Technology | Wang H.,Tianjin University of Technology | Han J.,Tianjin University of Technology | Song Z.,Tianjin University of Technology
Applied Surface Science | Year: 2012

A series of novel multifunctionalized SBA-15 with titanium and zirconium incorporated frameworks and ionic liquid filled ordered channels were synthesized for the first time, by combining framework doping and post-grafting. The as-prepared materials were extensively characterized to investigate the mesostructural and chemical properties. The results indicated that the products possess the periodically ordered mesoporous structure. Titanium and zirconium were efficiently introduced into the framework of the mesostructure, generating medium strong acid and basic sites. N-methylimidazole ionic liquid was covalently grafted into the channels of mesoporous materials. Moreover, a higher cooperative catalytic performance originated from the dual-metal centers and ionic liquid was shown in catalyzing the cycloaddition of carbon dioxide with epoxides. A plausible reaction mechanism was proposed based on the experimental results. © 2012 Published by Elsevier B.V.


Zhao J.-P.,Tianjin University of Technology | Zhao J.-P.,Nankai University | Zhao R.,Nankai University | Yang Q.,Nankai University | And 3 more authors.
Dalton Transactions | Year: 2013

Two MII tetranuclear complexes bridged only by azido, Mn 4(N3)7.3Cl0.7L4 (1) and Co4(N3)8L4 (2) in which the four MII ions are precisely coplanar bridged only by six azido anions, were obtained by using 4,5-diazafluoren-9-one (L) as a corner ligand. Magnetic studies indicate that ferromagnetic coupling was conducted by the azido anions between MII ions. At low temperature, 1 exhibits a large magnetocaloric effect and 2 shows field-induced multiple magnetic relaxations. © 2013 The Royal Society of Chemistry.


Ding X.,Tianjin University | Liu T.,Tianjin University | Song D.,Tianjin University | Song D.,Tianjin University of Technology
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2012

The quality of laser spot is studied in order to improve the precision of distance and thickness measurement system based on laser diode-position sensitive device (LD-PSD) laser triangulation. Static distance measuring experiments with different powers of laser diodes are conducted. The experimental results show that drift of the center of spot intensity increases measurement errors of the system in long-term continual work. The drift is mainly caused by high-frequency noise and spot displacement. For these two factors, an optical system based on the pinhole filter and beam splitter with prisms to improve the quality of laser spot is proposed, which is optimized and simulated by CODEV. Static distance measuring experiments are conducted again after adding the designed optical system to the rangefinder. The new experimental results prove that the precision of the system is improved from 25 μm to 8 μm. The design improves the practicability of laser triangulation measurement system for distance and thickness measuring in long-term continual work based on PSD.


Cao Y.,Tianjin University of Technology | Yang Y.,Tianjin University of Technology | Yang X.,Tianjin University of Technology | Tong Z.,Tianjin University of Technology
Chinese Optics Letters | Year: 2012

An alternative solution for the simultaneous measurement of temperature and refractive index is presented. A local micro-structured fiber Bragg grating (LMSFBG) is formed as the sensing head, in which a standard grating is etched by HF. According to the phase shift theory, the main spectral change of the LMSFBG is the formation of a narrow allowed band, which is strongly dependent on the etching features and the surrounding refractive index. As such, the temperature and refractive index measurements can be achieved by the shifts of the double peaks and narrow allowed band, and their fitting linearity coefficients are 0.996 and 0.994, respectively. Thus, the reflection and transmission peaks of the LMSFBG have a good linear relationship with temperature and refractive index. © 2012 Chinese Optics Letters.


Liu S.,Nanyang Technological University | Hu M.,Nanyang Technological University | Zeng T.H.,Nanyang Technological University | Wu R.,Nanyang Technological University | And 6 more authors.
Langmuir | Year: 2012

Graphene oxide (GO) is a promising precursor to produce graphene-family nanomaterials for various applications. Their potential health and environmental impacts need a good understanding of their cellular interactions. Many factors may influence their biological interactions with cells, and the lateral dimension of GO sheets is one of the most relevant material properties. In this study, a model bacterium, Escherichia coli (E. coli), was used to evaluate the antibacterial activity of well-dispersed GO sheets, whose lateral size differs by more than 100 times. Our results show that the antibacterial activity of GO sheets toward E. coli cells is lateral size dependent. Larger GO sheets show stronger antibacterial activity than do smaller ones, and they have different time- and concentration-dependent antibacterial activities. Large GO sheets lead to most cell loss after 1 h incubation, and their concentration strongly influences antibacterial activity at relative low concentration (<10 μg/mL). In contrast, when incubating with small GO sheets up to 4 h, the inactivation rate of E. coli cells continues increasing. The increase of small GO sheet concentration also results in persistent increases in their antibacterial activity. In this study, GO sheets with different lateral sizes are all well dispersed, and their oxidation capacity toward glutathione is similar, consistent with X-ray photoelectron spectroscopy and ultraviolet-visible absorption spectroscopy results. This suggests the lateral size-dependent antibacterial activity of GO sheets is caused by neither their aggregation states, nor oxidation capacity. Atomic force microscope analysis of GO sheets and cells shows that GO sheets interact strongly with cells. Large GO sheets more easily cover cells, and cells cannot proliferate once fully covered, resulting in the cell viability loss observed in the followed colony counting test. In contrast, small GO sheets adhere to the bacterial surfaces, which cannot effectively isolate cells from environment. This study highlights the importance of tailoring the lateral dimension of GO sheets to optimize the application potential with minimal risks for environmental health and safety. © 2012 American Chemical Society.


Nie X.,Tianjin University of Technology | Wang H.,Tianjin University of Technology | Zou J.,Tianjin University of Technology
Applied Surface Science | Year: 2012

Direct synthesis of silver conductive film on PET substrate by inkjet printing silver citrate conductive ink was presented in this paper. This kind of conductive ink contained silver citrate as silver precursor, 1,2-diaminopropane as complex agent dissolving the silver salt and methanol and isopropanol as a media adjusting the viscosity and surface tension. The formation of silver-amine complex reduced the decomposition temperature from 180 °C to 135 °C, thus the ink could be cured at relatively low temperature. The film reached the lowest resistivity of 17 μΩ cm after cured at 150 °C for 50 min, 3.1 μΩ cm at 230 °C and possessed high reflection and excellent adhesive property. Electrical conductivity, surface morphology and composition were investigated by four-point probe method, scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). It is demonstrated how the cured condition affects the silver film. Moreover, radio-frequency identification (RFID) antenna was fabricated by inkjet printing, which opens up routes for the flexible electronics fabrication. © 2012 Elsevier B.V. All rights reserved.


Tian L.,Tianjin University of Technology | Zhang A.,Tianjin University of Technology
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2010

Phase-shifted fiber Bragg grating and sampled fiber Bragg grating with dual wavelength filtering properties are designed and their properties with transmission matrix method are studied. As a result, both multi- π phase-shifted grating and π phase-shifted sampled grating have dual wavelength reflective profile. Moreover, the side lobe of reflective profile of π phase-shifted sampled grating is lower than that of multi- π phase-shifted grating. By adjusting the duty cycle of π phase-shifted sampled grating in the range of 0.66-0.8, better dual wavelength filtering profile is obtained, especially the side lobe reflective index is lowest when the duty cycle is 0.75.


Li R.,Tianjin University of Technology | Zhang M.,Tianjin University of Technology | Yu Y.,Tianjin University of Technology
Applied Surface Science | Year: 2012

Copper-based catalysts have shown excellent catalytic performances. Despite extensive studies in the field, the microscopic mechanism of ethanol dehydrogenation to ethyl acetate (EA) on Cu-based catalysts remains controversial. Aiming to provide insight into the catalytic roles of Cu, density functional theory (DFT) calculations have been performed to study the elementary reactions involved in ethanol dehydrogenation to EA on Cu surfaces. In this work, the adsorption properties of ethanol, ethoxy, acetaldehyde, acetyl and EA on the Cu (1 1 1) catalyst surface were investigated. Based on two pathways, many transition states involved are located. The results show that the route proposed by Colley is more likely to happen. © 2012 Elsevier B.V.


Liang X.,Tianjin University of Technology | Lin B.,Tianjin University of Technology | Han X.,Tianjin University of Technology | Chen S.,Tianjin University of Technology
Applied Surface Science | Year: 2012

Traditional methods of roughness characterization cannot properly reflect the differences between metal and engineering ceramics surfaces. Therefore, fractal method is introduced to characterize the engineering ceramics ground surface in this paper. This article compares various methods to calculate profile dimension. By comparison, the variation method is suitable for extracting fractal dimension of engineering ceramics ground surface. The precision of variation method is further improved by modifying the error. In view of engineering ceramics ground surface, we have analyzed the relationship between fractal dimension and traditional roughness parameters, surface texture, surface function and material property using modified variation method. © 2012 Elsevier B.V.


Li R.,Tianjin University of Technology | Cao Y.,Tianjin University of Technology | Tong Z.,Tianjin University of Technology
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2012

Based on the birefringence effect, a novel polarization splitter based on dual elliptical-core photonic crystal fiber (PCF) is proposed, the elliptical-core through introducing a pair of big air holes and a pair of small air holes in every core. The full-vector finite element method (FEM) and the semi-vector beam propagation method (BPM) are employed to analyze the performance of the splitter. Numerical simulations demonstrate that it is possible to obtain a 544 μm long polarization splitter, and the polarized light extinction ratio is -43.75 dB at the wavelength of 1.55 μm. Besides, the bandwith is over 80 nm when the extinction ratio is less than -10 dB. Such design provides a new approach to get highly extinction ratio and short length polarization splitter based on dual-core photonic crystal fiber.


Wang J.,Tianjin University of Technology | Tong Z.,Tianjin University of Technology | Yang X.,Tianjin University of Technology | Cao Y.,Tianjin University of Technology
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2012

Based on the multimode interference theory and the sensing characteristics of long-period fiber grating (LPFG), a fiber-optic sensor composed of a single mode fiber (SMF)-multimode fiber (MMF)-SMF (SMS) structure and a LPFG is proposed for simultaneous measurement of temperature and refractive index. The experimental results show that the interference spectrum of SMS structure and LPFG have different response sensitivities to temperature and refraction index, and the temperature sensitivity coefficients are 0.017 nm/°C and 0.060 nm/°C, respectively. The SMS structure is insensitive to refractive index while the refractive index sensitivity coefficient of LPFG is -35.60 nm/RIU. Using the sensitivity matrix, simultaneous measurement of temperature and refractive index is realized. The maximum measurement errors of temperature and refraction index are ±0.59°C and ±0.0013, respectively. With the advantages of high sensitivity, simple structure, immunity to electromagnetic interferences and good linearity, the structure has a excellent application prospect in biochemistry field.


Meng Y.-L.,Tianjin University of Technology | Wang B.-Y.,Tianjin University of Technology | Wang B.-Y.,Nankai University | Li S.-F.,Tianjin University of Technology | And 2 more authors.
Bioresource Technology | Year: 2013

A solid Ca/Al composite oxide-based alkaline catalyst containing Ca12Al14O33 and CaO was prepared by chemical synthesis and thermal activation from sodium aluminate solution and calcium hydroxide emulsion. The effect of calcination temperatures ranging from 120°C to 1000°C on activity of the catalyst was investigated. The catalyst calcined at 600°C showed the highest activity with >94% yield of fatty acid methyl esters (i.e. biodiesel) when applied to the transesterification of rapeseed oil at a methanol:oil molar ratio of 15:1 at 65°C for 3h. Structure and properties of the catalyst were studied and the characterizations with XRD, TGA, FTIR, BET, and SEM demonstrated that the performance of the catalyst was closely related to its specific surface area and crystalline structure. In particular, the generation of crystalline Ca12Al14O33 improved the catalytic activity due its synergistic effect with CaO. © 2012 Elsevier Ltd.


Wang L.-M.,Langfang Teachers College | Wu F.,Tianjin University of Technology
Wuli Xuebao/Acta Physica Sinica | Year: 2013

The dynamic behaviors of coupled fractional order bistable oscillators are investigated extensively and various phenomena such as synchronization, anti-synchronization, and amplitude death, etc. are explored. Based on the bistable characteristics of P-R oscillator with specific parameters, effects of initial conditions and coupling strength on the dynamic behaviors of the coupled fractional order bistable oscillators are first investigated by analyzing the maximum condition of Lyapunov exponent, the maximum Lyapunov exponent and the bifurcation diagram, etc. Further investigation reveals that the coupled fractional order bistable oscillators can be controlled to form chaotic synchronization, chaotic anti-synchronization, synchronous amplitude death, anti-synchronous amplitude death, partial amplitude death, and so on by changing the initial conditions and the coupling strength. Then, based on the principle of Monte Carlo method, by randomly choosing the initial conditions from the phase space, we calculate the percentage of various states when changing the coupling strength, so the dynamic characteristics of coupled fractional-order bistable oscillators can be represented by using the perspective of statistics. Some representative attractive basins are plotted, which are well coincident with numerical simulations. © 2013 Chinese Physical Society.


Meng Y.-L.,Tianjin University of Technology | Tian S.-J.,Tianjin University of Technology | Li S.-F.,Tianjin University of Technology | Wang B.-Y.,Nankai University | Zhang M.-H.,Tianjin University of Technology
Bioresource Technology | Year: 2013

A conventional trickle bed reactor and its modified type both packed with Ca/Al composite oxide-based alkaline catalysts were studied for biodiesel production by transesterification of rapeseed oil and methanol. The effects of the methanol usage and oil flow rate on the FAME yield were investigated under the normal pressure and methanol boiling state. The oil flow rate had a significant effect on the FAME yield for the both reactors. The modified trickle bed reactor kept over 94.5% FAME yield under 0.6. mL/min oil flow rate and 91. mL catalyst bed volume, showing a much higher conversion and operational stability than the conventional type. With the modified trickle bed reactor, both transesterification and methanol separation could be performed simultaneously, and glycerin and methyl esters were separated additionally by gravity separation. © 2013 Elsevier Ltd.


Wang W.,Nankai University | Zhou M.,Nankai University | Mao Q.,Nankai University | Yue J.,Nankai University | And 2 more authors.
Catalysis Communications | Year: 2010

NaY zeolite-supported nanoscale zero-valent iron (NZVI/NaY) was synthesized by in-situ reduction of exchanged iron ions. Composition and structural characterization showed that α-Fe nanoparticles (50- 100 nm) were supported on the surface of NaY zeolite. Catalytic efficiency of the composite powders was tested in degradation of potassium acid phthalate (KHP) solution (425 mg/L). At pH 3.5, the chemical oxygen demand (COD) removal ratio reached 79%. The NZVI/NaY exhibited efficient catalytic activity close to that of iron homogeneous catalyst but with less than 50% leaching of iron cations. Further, it performed well under much wider pH range (pH 1.7-5) compared to classic Fenton reagent, providing potential alternative as a novel heterogeneous Fenton catalyst for environmental remediation. © 2010 Elsevier B.V. All rights reserved.


Liu Y.,Tianjin University of Technology | Pan Y.-X.,Tianjin University of Technology | Kuai P.,Tianjin University of Technology | Liu C.-J.,Tianjin University of Technology
Catalysis Letters | Year: 2010

A dielectric-barrier discharge (DBD) plasma technique has been successfully applied for template removal from ZSM-5 zeolite. The rate for template removal using DBD is about eight times higher than that using the conventional thermal calcination. During the template removal using DBD, the highest temperature of the sample is about 125 °C. As such, the thermal effect on the sample during the DBD template removal is not significant. This made the structure changes of ZSM-5 zeolite during the template removal less dramatic than that using thermal calcination. © 2010 Springer Science+Business Media, LLC.


Liu L.,Tianjin University of Technology
Journal of Donghua University (English Edition) | Year: 2015

Nowadays, virtual human (VH) is becoming a hot research topic in virtualization. VH dialogue can be categorized as an application of natural language processing (NLP) technology, since it is relational to question and answering (QA) technologies. In order to integrate these technologies, this paper reviews some important work on VH dialogue, and predicts some research points on the view of QA technologies. Copyright © 2015 Editorial Department of Journal of Donghua University. All rights reserved.


Chen J.,Tianjin University | Qin S.,Tianjin University | Song G.,Tianjin University | Xiang T.,Tianjin University | And 2 more authors.
Dalton Transactions | Year: 2013

Different shape of bismuth sulfide (Bi2S3), including nanoparticles, and urchin-like, microspheres hierarchical nanostructures, have been successfully fabricated using a facile and template-free solvothermal method. Their crystal and porous structures, morphologies, as well as the optical absorption were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflection spectroscopy (DRS) and nitrogen sorption. The electron microscopy observations showed that both the sulfur sources and solvents greatly affected the morphologies of the as-prepared Bi2S3. Compared with Bi2S 3 nanoparticles, the hierarchical architectures exhibited higher activity for photocatalytic reduction of CO2 to methyl formate (MF) in methanol, and Bi2S3 microspheres showed the highest activity. This was attributed to their special hierarchical structure, good permeability and high light-harvesting capacity. © 2013 The Royal Society of Chemistry.


Lu S.,Tianjin University of Technology | Liu Y.,Tianjin University of Technology | Wang Y.,Tianjin University of Technology
Chemical Communications | Year: 2010

Meso-macro-porous monolithic Pt-Ni/Al2O3 catalysts with platinum and nickel in interaction and in a highly dispersed state have been successfully prepared, and the obtained catalysts are highly efficient for CO removal from hydrogen rich gases via preferential oxidation; the results show that preparing catalysts to meso-macro-porous monolithic structure is a promising way for the miniaturization of CO removing reactor. © 2010 The Royal Society of Chemistry.


Han S.-D.,Nankai University | Zhao J.-P.,Nankai University | Zhao J.-P.,Tianjin University of Technology | Liu S.-J.,Nankai University | Bu X.-H.,Nankai University
Coordination Chemistry Reviews | Year: 2015

Hydro(solvo)thermal synthesis is a widely-used method to assemble various molecular magnetic materials based on different types of ligands. This review mainly focuses on the study of the magnetochemistry of azide/formate-mediated molecule-based magnetic materials of our lab synthesized under hydro(solvo)thermal conditions in the presence of coligand, with an emphasis on anionic coligand of carboxylate. The first section gives a brief discussion of azido and formato complexes and some important principles obtained from magneto-structural correlation; hydro(solvo)thermal synthetic strategies will also be referred to and elucidated in this part. The next six sections give overviews of the main results obtained in our group in recent years, that is, azide/formate-mediated ferromagnetism, ferrimagnetism, spin canting (or weak ferromagnetism), antiferromagnetism, single-molecule magnets (SMMs) and single-chain magnets (SCMs), and metamagnetism. Finally, the conclusions and perspectives of azido/formato-mediated molecular magnetic materials will be presented. Some of the trends identified could provide new insights into the further development of this promising area. © 2014 Elsevier B.V..


Wang X.,Tianjin University of Technology | Liu Y.C.,Tianjin University of Technology | Gao Z.M.,Tianjin University of Technology
Journal of Materials Science: Materials in Electronics | Year: 2011

The effect of the Bi content on the formation of intermetallic compounds (IMCs) layers between the Sn-xBi-0.9Zn-0.3Ag lead-free solder (with x = 1, 2, 3 and 4, in weight percent, hereafter) and Cu substrate was investigated. The structure of the IMC layer in the soldered interface varies apparently with increasing the Bi content. When the Bi content is 1 wt%, the interface soldered is consisted of CuZn and Cu 6Sn 5 IMC layers, which are separated by an intermediate solder layer. As the Bi content increases, the spalling phenomenon tends to disappear. Moreover, the layer between the Sn-2Bi-0.9Zn-0.3Ag solder and Cu substrate is thicker than others. The evolution of the soldered interfacial structure could be attributed to the existence of Bi. © 2010 Springer Science+Business Media, LLC.


Li X.,Tianjin University of Technology | Li Y.,Tianjin University of Technology | Li Y.,National Engineering Research Center for Distillation Technology
Catalysis Letters | Year: 2014

A novel type of Ce-Mo-Oxcatalyst prepared by the facile coprecipitation method has been utilized for the selective catalytic reduction of NO with NH3. The catalyst showed excellent activity, prominent resistant to the space velocity in a temperature range from 200 to 400°C and exhibited high SO2/H2O durability at 300°C. XRD and in situ DRIFTS proved that the strong interactions between CeOx and MoOx in the catalyst could be the main reason for the excellent NH3-SCR catalytic performance. © 2013 Springer Science+Business Media New York.


Nie G.,Tianjin University of Technology | Zou J.-J.,Tianjin University of Technology | Feng R.,Tianjin University of Technology | Zhang X.,Tianjin University of Technology | Wang L.,Tianjin University of Technology
Catalysis Today | Year: 2014

Turpentine is biomass derived from metabolites of plants and often utilized via isomerization or dimerization of pure pinene that are separated from crude turpentine. This work is aimed to demonstrate the possibility of using crude turpentine to replace pure pinene in the acid catalyzed reactions. Firstly, H3PW12O40 (HPW) was loaded on MCM-41 using wet impregnation to enhance the dispersion of acid sites. Characterizations show that HPW is well dispersed and the acid concentration depends on the HPW amount. Then the isomerization and dimerization of α-pinene, β-pinene and crude turpentine were investigated in detail. Regardless the kind of reactant used, the product distribution is very similar in each type of reaction. Controlled experiment shows the dimerization involves a quick isomerization and thus the dimers are formed from the isomeric compounds. Moreover, components besides pinene, like oxygen-containing compounds, in crude turpentine also take part in the reactions. The reaction network is proposed based on experiment and theoretical computation. HPW/MCM-41 shows higher activity than bulk HPW, and 80% HPW/MCM-41 is the best, which leads to equal conversion (or yield) in the isomerization (or dimerization) for all the three reactants. This work shows that crude turpentine can be used to produce chemicals that are formed from pure pinene. © 2013 Elsevier B.V.


Yan B.,Tianjin University of Technology | Huang S.,Tianjin University of Technology | Wang S.,Tianjin University of Technology | Ma X.,Tianjin University of Technology
ChemCatChem | Year: 2014

Stable catalysts prepared by dispersing Cu2O nanoparticles on activated carbon were investigated in the oxidative carbonylation of methanol to dimethyl carbonate. The effect of the surface oxygen containing groups (OCGs) on the rate of dimethyl carbonate formation and the selectivities of the catalyst for dimethyl carbonate and the byproduct methyl formate were determined. The carbon support surface OCGs played a key role in the oxidative carbonylation. For carbon supports with the same amount of OCGs, the highest catalytic activity was achieved at a certain level of Cu loading. The optimal Cu loading as well as catalytic activity increased linearly with the amount of OCGs. The active sites of the catalysts were the Cu2O nanoparticles that coordinated to the OCGs on the carbon surface. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Cao Y.,Tianjin University of Technology | Li R.-M.,Tianjin University of Technology | Tong Z.-R.,Tianjin University of Technology
Wuli Xuebao/Acta Physica Sinica | Year: 2013

A kind of highly birefringent and highly nonlinear photonic crystal fiber (PCF) is proposed. The fundamental mode field, birefringence, nonlinear coefficient, effective mode area and dispersion characteristic of the fiber are studied by the full-vector finite element method. Simulation results show that the birefringence becomes larger by reducing the air hole pitch, and the birefringence reaches up to 10-2 at a wavelength of 1550 nm, which is about two orders of magnitude higher than that of the regular elliptic polarization maintaining fiber. At the same time, a nonlinear coefficient of 42 W-1·km-1 is obtained. There are two zero dispersion wavelengths in the visible and the near-infrared region respectively, and flattened chromatic dispersion from 800 nm to 2000 nm is obtained. Such a design provides a new approach to obtaining highly birefringent and highly nonlinear PCF, and the fiber has a broad prospect of application in the polarization control, nonlinear optics and dispersion control. © 2013 Chinese Physical Society.


Yan F.,Tianjin University of Technology | Xia S.,Tianjin University of Technology | Wang Q.,Tianjin University of Technology | Wang Q.,Tianjin University of Science and Technology | Ma P.,Tianjin University of Technology
Journal of Chemical and Engineering Data | Year: 2012

In this work a new topological index (TI) was proposed based on atom characteristics (e.g., atom radius, atom electronegativity, etc.) and atom positions in the hydrogen-suppressed molecule structure. Using the TIs, a multiple linear regression (MLR) model was developed for predicting the decomposition temperature (T d) of 158 ionic liquids (ILs), which are based on imidazolium, pyridinium, pyrrolidinium, ammonium, phosphonium, sulfonium, and guanidinium. Because ILs are a class of molten salts which are composed entirely of cations and anions, in general, the descriptors for ILs are calculated from cations and anions separately, and the interaction between them is neglected. In this study, except for the two sets of TIs generated from cations and anions, a third TI was proposed to depict the interaction of anions and cations. The regression coefficient (R 2) and the overall average absolute deviation (AAD) are 0.893 and 3.07 %, respectively. © 2012 American Chemical Society.


Wang G.,Tianjin University of Technology | Chen J.,University of Queensland | Tian Y.,Tianjin University of Technology | Jin Y.,Tianjin University of Technology | Li Y.,Tianjin University of Technology
Catalysis Today | Year: 2012

Double-walled carbon nanotubes (DWCNTs) with a narrow diameter distribution have been synthesized with the assistance of water vapor in a fluidized-bed reactor from methane over a Co-Mo/MgO catalyst. The results reveal that an appropriate amount of water enhances the carbon yield and also changes the diameter distribution of the DWCNTs. An excess amount of water depresses the formation of carbon nanotubes due to the stabilization of the Co-molybdate phase. Water facilitates the formation of adjacent Co and CoO phases, and therefore methane activation and carbon nanotube formation. The formation of adjacent Co and CoO phases results in smaller Co nanoparticles. DWCNTs with narrow diameter distribution are produced with this method at a low cost. © 2011 Elsevier B.V.


Yang C.,Tianjin University of Technology | Yin X.,Tianjin University of Technology | Ma S.,Tianjin University of Technology
Journal of Chemical and Engineering Data | Year: 2012

Isobaric vapor-liquid equilibrium (VLE) data for the systems dimethyl carbonate (DMC) + methanol and DMC + methanol + tetramethylammonium bicarbonate (TMAB) at different salt mole fractions (0.04, 0.07, and 0.10) have been measured at 101.32 kPa. The bubble-point data of the system methanol + TMAB have also been measured at different salt mole fractions. The addition of the organic salt TMAB has a salting-out effect on DMC, and the effect would be enhanced with the increasing salt concentration. The VLE data of the salt-containing system were predicted by the modified Wilson and nonrandom two-liquid (NRTL) models proposed by Tan. The average deviations for the mole fraction of the vapor phase and the bubble point by the modified predictive model were: Δy = 0.011, ΔT = 0.6 K. © 2011 American Chemical Society.


Jiang D.,Tianjin University of Technology | Zhang M.,Tianjin University of Technology | Li G.,Tianjin University of Technology | Jiang H.,Tianjin University of Technology
Catalysis Communications | Year: 2012

Hollow and solid MnO x-CeO 2 nanospheres have been successfully prepared with a supercritical anti-solvent process and used for the selective catalytic reduction of NO with NH 3. Solid solution structures are detected for these nanospheres. The hollow MnO x-CeO 2 nanospheres have more oxygen vacancies than the solid ones. And they also present a better NO conversion in the low-temperature range of 100-200°C. Higher surface area, better oxygen mobility and richer surface active oxygen species are responsible for the better performance of the hollow sample. Therefore, the supercritical anti-solvent preparation of the nanospheres with the hollow structure is more favorable for the low-temperature selective catalytic reduction of NO. © 2011 Elsevier B.V. All rights reserved.


Pan P.,Zhejiang University | Yang J.,Tokyo Institute of Technology | Yang J.,Tianjin University of Technology | Shan G.,Zhejiang University | And 3 more authors.
Macromolecular Materials and Engineering | Year: 2012

The effects of nucleobases, especially uracil, on the nonisothermal and isothermal crystallization, melting behavior, spherulite morphology, and crystalline structure of bio-based and biodegradable PLLA are studied. The melt- and cold-crystallization rates of PLLA increase with increasing uracil loading. The melting behavior of nonisothermally melt- and cold-crystallized PLLAs depends on the uracil content. The isothermal crystallization kinetics is analyzed based on an Avrami model. The incorporation of uracil changes the t 1/2/T c profile of PLLA due to the more distinct heterogeneous nucleation effects at small supercooling. The crystalline structure of PLLA is not affected by uracil presence. The nucleation density increases and the spherulite size decreases by uracil incorporation. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Rong M.,Yunnan Normal University | Wang J.,Tianjin University of Technology | Shen Y.,Yunnan Normal University | Han J.,Tianjin University of Technology
Catalysis Communications | Year: 2012

A selective oxidation of alcohols to corresponding carbonyl compounds in ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate([bmim]BF 4) was achieved by using a novel salicylaldehyd amino acid Schiff base manganese ligand. The catalytic system can be recycled and reused for four runs without any significant loss of catalytic activity. © 2011 Elsevier B.V. All rights reserved.


Krishnan D.,Northwestern University | Raidongia K.,Northwestern University | Shao J.,Northwestern University | Shao J.,Tianjin University of Technology | Huang J.,Northwestern University
ACS Nano | Year: 2014

Hydrothermal carbonization (HTC) of biomass such as glucose and cellulose typically produces micrometer-sized carbon spheres that are insulating. Adding a very small amount of Graphene oxide (GO) to glucose (e.g., 1:800 weight ratio) can significantly alter the morphology of its HTC product, resulting in more conductive carbon materials with higher degree of carbonization. At low mass loading level of GO, HTC treatment results in dispersed carbon platelets of tens of nanometers in thickness, while at high mass loading levels, free-standing carbon monoliths are obtained. Control experiments with other carbon materials such as graphite, carbon nanotubes, carbon black, and reduced GO show that only GO has significant effect in promoting HTC conversion, likely due to its good water processability, amphiphilicity, and two-dimensional structure that may help to template the initially carbonized materials. GO offers an additional advantage in that its graphene product can act as an in situ heating element to enable further carbonization of the HTC products very rapidly upon microwave irradiation. Similar effect of GO is also observed for the HTC treatment of cellulose. © 2013 American Chemical Society.


Wang B.,Tianjin University of Technology | Ran W.,Tianjin University of Technology
Chemical Engineering Communications | Year: 2012

Recently developed catalytic processes with hydrophobic catalysts supported over styrene-divinylbenzene copolymer (SDB) were reviewed. Applications of such catalytic processes in commercial chemicals production and environmental management were examined in great detail. Based on this research work, the feasibility of hydrophobic catalysts over SDB utilized in the synthesis of methyl methacrylate (MMA) from methacrolein (MAL) in molecular O 2 was evaluated. © 2012 Copyright Taylor and Francis Group, LLC.


Zang J.,Tianjin University | Jia S.,Tianjin University | Liu Y.,Tianjin University of Technology | Wu S.,Tianjin University | Zhang Y.,Tianjin Entry and Exit Inspection and Quarantine Bureau
Catalysis Communications | Year: 2012

In this paper, polyvinyl alcohol (PVA) was modified with 3-aminopropyl triethoxysilane (APTES) and formed chemically crosslinked beads with chitosan. FTIR and SEM were used to characterize the support and immobilized catalase. Compared with control group, the activity of modified group increased about 1400 U/g support. The optimal temperature and optimal pH of immobilized catalase were 45°C and pH 7.0. The thermal stability of catalase also enhanced after immobilization. Moreover, the immobilized catalase retained more than 90% of its original activity after using it for 9 times. © 2012 Elsevier B.V.


Wu Q.,Tianjin University | Wu Q.,Tianjin University of Technology | Zhao J.,Tianjin University | Qin G.,Tianjin University | And 3 more authors.
Applied Catalysis B: Environmental | Year: 2013

The performance of photocatalytic reduction of chromium (VI) via a new TiO2 film and a platinum anode was systematically evaluated. The as-prepared TiO2 film is composed of a dye-sensitized zone and a catalysis zone. Charge separation was accomplished with electron transferring to the catalysis zone and positive charge transforming to an anode. A powerful reduction ability of the reaction system was achieved in the absence of any organics under visible light irradiation. Several parameters including pH, dissolved O2, the primary active species, the durability of the as-synthetized film and so on were investigated. © 2013 Elsevier B.V.


Guo X.,Tianjin University of Technology | Meng M.,Tianjin University of Technology | Dai F.,Tianjin University of Technology | Li Q.,University of Jinan | And 4 more authors.
Applied Catalysis B: Environmental | Year: 2013

A series of dually substituted perovskite catalysts La1-xKxCo1-yPdyO3-δ (x=0, 0.1; y=0, 0.05) were successfully synthesized through a citrate-based sol-gel process, and employed for soot combustion in the presence of NOx. The physicochemical properties of them were systematically characterized by N2-sorption, XRD, XPS, SEM, HRTEM, XANES, EXAFS, H2-TPR, soot-TPR, FT-IR and TG/DTA. The activity evaluation results show that among all catalysts La0.9K0.1Co0.95Pd0.05O3-δ possesses the highest performance, exhibiting the lowest Ti and Tm (219°C and 360°C), the narrowest temperature range (Tf-Ti=162°C) and the lowest activation energy (93.6kJ/mol) for soot combustion. The catalyst La0.9K0.1Co0.95Pd0.05O3-δ shows relatively larger BET surface area, smaller crystallite size and higher dispersion of Pd. Additionally, this catalyst also possesses the best reducibility and highest oxidibility as revealed by H2-TPR and soot-TPR. The Pd ions with high valence (Pd3+, Pd4+) in distorted octahedral coordination environment as demonstrated by XPS, XANES and EXAFS are much more active for NO oxidation and soot combustion than the bivalent Pd ions with square-planar coordination symmetry. Based upon the characterization results and catalytic performance, a mechanism containing two reaction pathways namely direct soot oxidation by surface adsorbed oxygen species in oxygen vacancies and the NO2-assisted soot oxidation is proposed. © 2013 Elsevier B.V.


Yang X.,East China University of Science and Technology | Tian P.-F.,East China University of Science and Technology | Zhang C.,Tianjin University of Technology | Deng Y.-Q.,East China University of Science and Technology | And 3 more authors.
Applied Catalysis B: Environmental | Year: 2013

The development of a new method for the degradation of bisphenol A (BPA) in aqueous solution is highly desired. Oxidative degradation using hydroxyl radicals (OH) is an efficient approach for the remedy of toxic organic compounds. This paper describes the design and utilization of a new Fenton system consisting of the Au/styrene based activated carbon catalyst and hydrogen peroxide (H2O2) for the degradation of BPA under non-photo-induced conditions. Transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results showed that the negatively charged Au nanoparticles were evenly distributed in a range 3.9-6.4nm dominated with (110) facet. The generation of OH over Au catalysts through the decomposition of H2O2 was evidenced using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) trapped electron paramagnetic resonance (EPR). The experimental results suggested that the conversion of BPA was affected by several factors such as the loading amount of Au, pH value, reaction temperature and the initial concentration of H2O2. In an optimum experiment, BPA could be degraded from 110 to 10ppm within 12h. The active sites was envisaged to be negatively charged Au atoms at the interface between Au particles and carbon support, the carbon surface is enriched with dangling carbon atoms as evidenced by the O2-temperature programmed desorption (TPD) technique. A mechanism including the redox between Auδ-↔Au° during the decomposition of H2O2 has been proposed. © 2013 Elsevier B.V.


Wu F.-Y.,Tianjin University of Technology
Gongcheng Kexue Xuebao/Chinese Journal of Engineering | Year: 2015

An analytical model of air-gap flux density and the Lorenz force law were used to establish radial and tangential electromagnetic force models in the spherical coordinate system for the stator coils. Then, a finite element model of the stator casing and coil holder was applied to compute the strain of the coil holder caused by electromagnetic force, and the influences of the stator casing's thickness, the diameter and the length of the coil holder's connecting rod on this strain were analyzed. Finally, the finite element method and the analytical method were used to analyze a prototype motor and their results were compared, which verified the validity and accuracy of the analytical models. This analysis shows that when the stator casing becomes thin or the connecting rod slenderizes, the strain of the stator coil holder produced by electromagnetic force increases linearly within a certain range and then grows significantly. ©, 2015 All right reserved.


Chang X.,Tianjin University of Technology | Wang T.,Tianjin University of Technology | Gong J.,Tianjin University of Technology
Energy and Environmental Science | Year: 2016

Large amounts of anthropogenic CO2 emissions associated with increased fossil fuel consumption have led to global warming and an energy crisis. The photocatalytic reduction of CO2 into solar fuels such as methane or methanol is believed to be one of the best methods to address these two problems. In addition to light harvesting and charge separation, the adsorption/activation and reduction of CO2 on the surface of heterogeneous catalysts remain a scientifically critical challenge, which greatly limits the overall photoconversion efficiency and selectivity of CO2 reduction. This review describes recent advances in the fundamental understanding of CO2 photoreduction on the surface of heterogeneous catalysts and particularly provides an overview of enhancing the adsorption/activation of CO2 molecules. The reaction mechanism and pathways of CO2 reduction as well as their dependent factors are also analyzed and discussed, which is expected to enable an increase in the overall efficiency of CO2 reduction through minimizing the reaction barriers and controlling the selectivity towards the desired products. The challenges and perspectives of CO2 photoreduction over heterogeneous catalysts are presented as well. © 2016 The Royal Society of Chemistry.


Ma C.,Tianjin University of Technology | Zhu L.,Tianjin University of Technology | Chen S.,Tianjin University of Technology | Zhao Y.,Tianjin University of Technology
Materials Letters | Year: 2013

Cu(OH)2 nanowires were prepared rapidly by the precipitation method at room temperature, using CuCl2, K2CO3 and NaOH as raw materials. Hierarchical copper oxide nanowires were obtained via a simple thermal conversion reaction of the Cu(OH)2 nanowires at 300 C for 2 h. The influence of reaction conditions on morphologies of the CuO products and the reaction mechanism were studied based on series of control experiments. The crystal structure and morphologies of the products were characterized and the optical properties of the CuO nanowires were investigated by UV-vis diffuse reflection absorption spectrum and fluorescence spectrum. The results show that the hierarchical CuO nanowire is about 10-15 nm in diameter and 300-500 nm in length with a primary particle size of 12.4 nm. The usage of K2CO3 and adequate NaOH is decisive for formation of the CuO nanowires. This preparation can be simply scaled up for a mass production. © 2013 Elsevier B.V.


Sun J.,University of Nottingham | Sun J.,Tianjin University of Technology | Kaban A.,University of Birmingham | Garibaldi J.M.,University of Nottingham
Pattern Recognition Letters | Year: 2010

A mixture of Student t-distributions (MoT) has been widely used to model multivariate data sets with atypical observations, or outliers for robust clustering. In this paper, we developed a novel robust clustering approach by modeling the data sets using mixture of Pearson type VII distributions (MoP). An EM algorithm is developed for the maximum likelihood estimation of the model parameters. An outlier detection criterion is derived from the EM solution. Controlled experimental results on the synthetic datasets show that the MoP is more viable than the MoT. The MoP performs comparably if not better, on average, in terms of outlier detection accuracy and out-of-sample log-likelihood with the MoT. Furthermore, we compared the performances of the Pearson type VII and the student t mixtures on the classification of several real pattern recognition data sets. The comparison favours the developed Pearson type VII mixtures. © 2010 Elsevier B.V. All rights reserved.


Song X.-F.,Tianjin University of Technology | Jin C.-X.,Tianjin Medical University | Yin L.,James Cook University
Journal of the Mechanical Behavior of Biomedical Materials | Year: 2015

Enamel cutting using dental handpieces is a critical process in tooth preparation for dental restorations and treatment but the machinability of enamel is poorly understood. This paper reports on the first quantitative assessment of the enamel machinability using computer-assisted numerical control, high-speed data acquisition, and force sensing systems. The enamel machinability in terms of cutting forces, force ratio, cutting torque, cutting speed and specific cutting energy were characterized in relation to enamel surface orientation, specific material removal rate and diamond bur grit size. The results show that enamel surface orientation, specific material removal rate and diamond bur grit size critically affected the enamel cutting capability. Cutting buccal/lingual surfaces resulted in significantly higher tangential and normal forces, torques and specific energy (p<0.05) but lower cutting speeds than occlusal surfaces (p<0.05). Increasing material removal rate for high cutting efficiencies using coarse burs yielded remarkable rises in cutting forces and torque (p<0.05) but significant reductions in cutting speed and specific cutting energy (p<0.05). In particular, great variations in cutting forces, torques and specific energy were observed at the specific material removal rate of 3mm3/min/mm using coarse burs, indicating the cutting limit. This work provides fundamental data and the scientific understanding of the enamel machinability for clinical dental practice. © 2014 Elsevier Ltd.


Liu T.,Tianjin University of Technology | Wang Z.,Tianjin University of Technology | Xia S.,Tianjin University of Technology | Ma P.,Tianjin University of Technology
Journal of Chemical Thermodynamics | Year: 2012

The isobaric (vapour + liquid) equilibrium (VLE) of N-formylmorpholine with aromatics (ethylbenzene, n-butylbenzene, isopropylbenzene, 1,2,4- trimethylbenzene) at 101.33 kPa was investigated. The experimental VLE data for the four binary systems were tested and verified to be thermodynamically consistent by the Herington analysis method. At the same time, the non-random two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) activity coefficient models were used to correlate the experimental data with temperature-independent parameters. The average absolute deviations of the temperature correlated by NRTL model and UNIQUAC model for all the systems are below 0.62 K and the average absolute deviations for the vapour phase compositions are all below 0.083. In addition, the UNIFAC (Do) group contribution model was used to correlate and estimate the VLE data. The N-formylmorpholine was treated as a group (NFM). The group interaction parameters for CH 2-NFM, ACH-NFM and ACCH 2-NFM were regressed. The UNIFAC (Do) model can correlate the experimental data well. The group interaction parameters were used to estimate VLE data of the (o-xylene + N-formylmorpholine), (m-xylene + N-formylmorpholine) and (p-xylene + N-formylmorpholine) binary systems. The estimated data fit well with the literature data. The average absolute deviations of the temperature for N-formylmorpholine with (o-xylene, m-xylene, p-xylene) are 1.67 K, 1.77 K and 1.35 K, respectively, and the average absolute deviations for the vapour phase compositions of o-xylene, m-xylene and p-xylene are 0.0133, 0.0057 and 0.0059, respectively. © 2012 Elsevier Ltd. All rights reserved.


Xia C.-Y.,Tianjin University of Technology | Xia C.-Y.,University of Zaragoza | Meloni S.,University of Zaragoza | Meloni S.,Third University of Rome | Moreno Y.,University of Zaragoza
Advances in Complex Systems | Year: 2012

Nowadays, our society is characterized by high levels of social cohesion and cooperation that are in contrast with the selfish nature of human beings. One of the principal challenges for the social sciences is to explain the emergence of agglomeration and cooperative behavior in an environment characterized by egoistic individuals. In this paper we address this long standing problem with the tools given by evolutionary game theory. Specifically, we explore a model in which selfish individuals interact in a public goods creation environment. As a further ingredient each agent is characterized by an individual expectation and, if unsatisfied, can change its location. In this scenario we study the effects of the knowledge of other players' performances on both cooperation and agglomeration and discuss the results in the context of previous and related works. Our results show that cooperation and agglomeration are generally robust against the inclusion of different information on other player performances and, in some cases, it can produce an enhancement of the cooperative behavior. Moreover, our results demonstrate that only in extreme and very competitive environments cooperation and agglomeration are lost. © 2012 World Scientific Publishing Company.


Mei Y.,Tianjin University of Technology | Cao Y.,Tianjin University | Chen G.,Tianjin University | Li X.,Tianjin University of Technology | And 2 more authors.
IEEE Transactions on Device and Materials Reliability | Year: 2013

Sintering of nanosilver paste has been extensively studied as a lead-free die-attach solution for bonding semiconductor chips. The bonding process typically consists of a low-temperature drying step to remove organic solvents in the paste followed by sintering at around 250 °C. Normally, a soak time of several minutes at the sintering temperature is necessary to establish strong bond strength by the conventional heating method. In this paper, we tested the feasibility of applying pulses of alternating electrical current through the nanosilver bonding layer to achieve strong joints in less than a second, not minutes. Experiments were carried out by joining rectangular copper blocks that were either coated with a layer of electroplated silver or without. A layer of nanosilver paste was stencil printed on one block, dried at temperature below 100 °C, before the other copper block was placed on. The bonding members were then inserted under an alternating-current spot-welding machine for rapid joining with current pulses. Die-shear test was used to quantify the joint strength. Investigated processing variables on the joint strength were current level, current-on time, nanosilver bondline thickness, predrying temperature and time, and copper surface finish. Scanning electron microscopy was used to characterize the joint microstructure. It is suggestive that the current sintering of nanosilver paste could be used for rapid joining of metal-to-metal connection, such as bonding copper bus bars onto power electronics modules. © 2001-2011 IEEE.


Song Q.,Tianjin Chengjian University | Shi K.,Tianjin University of Technology
Journal of Intelligent and Fuzzy Systems | Year: 2014

This paper discusses on the problem of optimal decisions for waiting time contract in a fuzzy public health care market with two participants: the public health administration (PHA) and the patient. In order to maximize the expected utility of the PHA, a fuzzy waiting time model is established in the framework of principal-agent theory, where the PHA's assessment on the patient's health index is subjective, and should be described as a fuzzy variable. The equivalent model is then provided to get the optimal solution. The results illustrate that if the patient's health index is higher, he may spend more time on waiting and less money on public treatment; the optimal contract depends only on utility function of PHA, so long as patient's utility rises in his wealth; treating patient with relatively lower or relatively higher health index make less utility for the PHA, and only treating patient with a special moderate health index can make the PHA's utility reach highest value. Finally, a numerical example is provided, which illustrates the effectiveness of the presented model. © 2014-IOS Press and the authors. All rights reserved.


Feng C.,Shanghai JiaoTong University | Zhang J.,Shanghai JiaoTong University | He Y.,Tianjin University | Zhong C.,Tianjin University of Technology | And 5 more authors.
ACS Nano | Year: 2015

Two-dimensional materials often show a range of intriguing electronic, catalytic, and optical properties that differ greatly from conventional nanoparticles. Herein, we demonstrate the large-scale preparation of sub-3 nm atomic layers Co3O4nanofilms with a nonsurfactant and substrate-free hydrothermal method. This successful preparation of ultrathin nanofilms highlighted the reconstruction of cobalt-ammonia complexes and synergistic effect of free ammonia and nitrate on film growth control. Subsequent performance tests uncovered that these sub-3 nm atomic layer Co3O4nanofilms exhibited an ultrahigh specific capacitance of 1400 F/g in the first galvanostatic charge/discharge test. The specific capacitance of Co3O4nanofilms only slightly decayed less than 3% after 1500 cycling tests. With some parameter adjustments, similar Co(OH)2nanofilms with a thickness of 3.70 ± 0.10 nm were also prepared. The Co(OH)2nanofilms possessed maximum specific capacitance of 1076 F/g and peak performance attenuation of about 2% after a cycle stability test. © 2015 American Chemical Society.


Bai Y.-C.,South China University of Technology | Zhang W.-D.,South China University of Technology | Chen C.-H.,South China University of Technology | Zhang J.-Q.,Tianjin University of Technology
Journal of Alloys and Compounds | Year: 2011

PtAu-alloy nanoparticles supported on multi-walled carbon nanotubes (MWCNTs) were successfully prepared by simultaneous reduction of H 2PtCl6·6H2O and HAuCl 4·3H2O with sodium borohydride as a reducing reagent and sodium citrate as a stabilizing reagent. The morphology and composition of the composite catalyst were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The results show that the PtAu alloy nanoparticles with an average diameter of about 3.5 nm and narrow size distribution are supported on MWCNTs. Electrocatalytic oxidation of formic acid at the PtAu/MWCNTs nanocomposite electrode was investigated in a solution containing 0.50 M H2SO 4 as a supporting electrolyte and 0.50 M formic acid by cyclic voltammogram and chronoamperometry. The results demonstrate that the PtAu/MWCNTs catalyst exhibits higher activity and stability for electro-oxidation of formic acid than the commercial Pt/C catalyst, reflecting by its lower onset potential (-0.05 V), oxidation mainly occurring in low potential range of -0.05 ± 0.65 V and higher peak current density of 3.12 mA cm-2. The result of CO stripping voltammetry discloses that gold in the PtAu/MWCNTs nanocomposite enhances the catalytic activity and stability. © 2010 Elsevier B.V. All rights reserved.


Wang X.W.,Tianjin University of Technology | Wang X.W.,Tianjin Key Laboratory for Photoelectric Materials and Devices | Yuan Z.H.,Tianjin University of Technology | Fang B.C.,Tianjin University of Technology
Materials Chemistry and Physics | Year: 2011

Ni nanotube arrays with different diameters were fabricated in the pores of the porous anodic alumina membranes by direct current electrodeposition. The crystal structure and micrograph of Ni nanotube arrays were characterized by X-ray diffraction, transmission electron microscopy, and field-emission scanning electron microscopy. The results indicate that Ni nanotubes have no preferred orientation and are polycrystalline structure. The magnetic behaviors of Ni nanotube arrays with different diameters are investigated, and the coercivity of Ni nanotubes depends strongly on their diameters. The size-dependent behavior of the coercivity is qualitatively explained in terms of localized magnetization reversal. © 2010 Elsevier B.V. All rights reserved.


Cai H.-Y.,Tianjin University of Technology | Li H.-Y.,Tianjin University of Technology | Zhu M.,Tianjin University of Technology | Huang Z.-H.,Tianjin University of Technology
Guangxue Jingmi Gongcheng/Optics and Precision Engineering | Year: 2013

On the basis of the Michelson interferometer, a phase interference measurement system with one single arm as the measurement output port was designed to measure and analyze the thickness uniformity of a glass plate. In the system, a CCD camera was used to collect the interference pattern and the Fourier transform fringe analysis and phase unwrapping techniques were used to extracted the phase information contained in the interference pattern. For the problem that the sidelobe center of Fourier transform spectrum could not be accurately located, an applicable triangular transformation method was proposed to extract the volume of phase change directly. With this approach, the phase results could be obtained more accurately without knowing the central location of the spectral sidelobe, meanwhile, the errors induced by man-made estimation and the small carrier frequency component in vertical axis were eliminated. The thickness uniformity of a group of glass plates was measured in both of the length and width directions. The experimental results show that the theoretical accuracy is 0.93% and 0.92% in two directions, respectively, when they measured by a CCD camera with a unit size of 4.65 μm×4.65 μm. The system can measure the thickness uniformity of the glass plates, and has lower demands for the location accuracy of frequency spectral sidelobe and the direction precision of carrier frequency.


Guo A.,Tianjin University of Technology | Liu J.,Tianjin University of Technology | Dong X.,Tianjin University of Technology | Liu M.,Tianjin University of Technology
Materials Letters | Year: 2013

Porous silica ceramics were successfully prepared from silica spinning solution and introduced silica particles by electrospinning. After sintering, the sample was mainly composed of the introduced silica particles instead of the electrospun ceramic fibers. Therefore, the role of the introduced particles in this work was quite different from that of the introduced fillers in other electrospinning works. The porosity of the samples sintered at 1000 °C and 1200 °C were 62.4% and 55.6%, respectively. Furthermore, the porosity of the sintered sample can be adjusted by changing the content of the introduced silica particles. This method can be extended to prepare other porous ceramics just by changing the kinds of introduced particles. © 2012 Elsevier B.V.


Wang J.,Tianjin University of Technology | Yue X.,Tianjin University of Technology | Zhang Z.,Tianjin University of Technology | Yang Z.,Tianjin University of Technology | And 5 more authors.
Advanced Functional Materials | Year: 2012

Design and fabrication of hierarchically structured membranes with high proton conductivity is crucial to many energy-relevant applications including proton exchange membrane fuel cell (PEMFC). Here, a series of imidazole microcapsules (IMCs) with tunable imidazole group loading, shell thickness, and lumen size are synthesized and incorporated into a sulfonated poly(ether ether ketone) (SPEEK) matrix to prepare composite membranes. The IMCs play two roles: i) Improving water retention properties of the membrane. The IMCs, similar to the vacuoles in plant cells, can render membrane a stable water environment. The lumen of the IMCs acts as a water reservoir and the shell of IMCs can manipulate water release. ii) They form anhydrous proton transfer pathways and low energy barrier pathways for proton hopping, imparting an enhanced proton transfer via either a vehicle mechanism or Grotthuss mechanism. In particular, at the relative humidity (RH) as low as 20%, the composite membrane exhibits an ultralow proton conductivity decline and the proton conductivity is one to two orders of magnitude higher than that of SPEEK control membrane. The enhanced proton conductivity affords the composite membrane an elevated peak power density from 69.5 to 104.5 mW cm -2 in a single cell. Moreover, the application potential of the composite membrane for CO 2 capture is explored. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Wang W.,Tianjin University of Technology | Jin Z.,Tianjin University of Technology | Liu H.,Tianjin University of Technology
Journal of the American Ceramic Society | Year: 2011

High crystalline and single-phase chalcopyrite CuInSe2 nanocrystals were synthesized at 180°C by a air pressure organic solvent phase synthesis using green and relative high boiling point 1-methyl-2- pyrrolidinone polar solvent, and sodium selenite, copper(II) chloride, and indium(III) chloride were used as inorganic precursor sources. The crystallization, morphology, chemical stoichiometry, and light property of the deposited products were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy, X-ray photoelectron spectra (XPS), energy-dispersive X-ray spectroscopy, and UV-vis-NIR absorption spectrum. The influence of the Cu:In:Se mol ratios in initial precursor solutions on chemical stoichiometry and phase composition of the resultant nanocrystals was investigated. And the chemical reaction mechanism involved in the organic solvent phase synthesis process was discussed based on XRD and XPS analysis. © 2011 The American Ceramic Society.


Sun J.,University of Nottingham | Sun J.,Tianjin University of Technology | Kaban A.,University of Birmingham
IEEE Transactions on Neural Networks | Year: 2010

In experimental and observational sciences, detecting atypical, peculiar data from large sets of measurements has the potential of highlighting candidates of interesting new types of objects that deserve more detailed domain-specific f