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Effect of cobalt oxide on performance of Pd catalysts for lean-burn natural gas vehicles in the presence and absence of water vapor

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Journal of Natural Gas Chemistry 2010年第2期19卷 134-138页

作者： Enyan Long Xiaoyu Zhang Yile Li Zhimin Liu Yun Wang Maochu Gong Yaoqiang Chen Key Laboratory of Green Chemistry ＆ Technology Ministry of Education College of Chemistry Sichuan University Chengdu 610064 Sichuan China

Pd-based catalysts modified by cobalt were prepared by co-impregnation and sequential impregnation methods,and characterized by X-ray powder diffraction （XRd）,N2 adsorption/desorption （Brunauer-Emmet-Teller method）,CO-chemisorption and X-ray photoelectron spectroscopy （XPS）.The activity of Pd catalysts was tested in the simulated exhaust gas from lean-burn natural gas *** effect of Co on the performance of water poisoning resistance for Pd catalysts was estimated in the simulated exhaust gas with and without the presence of water *** was found that the effect of Co significantly depended on the preparation ***/La-Al2O3 catalyst prepared by co-impregnation exhibited better water-resistant *** results of XPS indicated that both CoAl2O4 and Co3O4 were present in the Pd catalysts modified by *** the catalyst prepared by sequential impregnation method,the ratio of CoAl2O4/Co3O4 was higher than that of the catalyst prepared by co-impregnation *** could be concluded that Co3O4 played an important role in improving water-resistant performance.

关键词： Co Pd-only catalyst lean-burn natural gas vehicles methane oxidation water vapor

Parallel algorithm and its convergence of spatial domain decomposition of discrete ordinates method for solving radiation heat transfer problem

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Chinese Journal of Aeronautics 2015年第1期28卷 77-85页

作者： Wang Zhenhua He Zhihong Mu Lei dong Shikui School of Energy Science and Engineering Harbin Institute of Technology

To improve the computational efficiency and hold calculation accuracy at the same time,we study the parallel computation for radiation heat transfer. In this paper, the discrete ordinates method（dOM） and the spatial domain decomposition parallelization（ddP） are combined by message passing interface（MPI） language. The ddP–dOM computation of the radiation heat transfer within the rectangular furnace is described. When the result of ddP–dOM along one-dimensional direction is compared with that along multi-dimensional directions, it is found that the result of the latter one has higher precision without considering the medium scattering. Meanwhile, an in-depth study of the convergence of ddP–dOM for radiation heat transfer is made. Analyzing the cause of the weak convergence, we relate the total number of iteration steps when the convergence is obtained to the number of sub-domains. When we decompose the spatial domain along one-,two- and three-dimensional directions, different linear relationships between the number of total iteration steps and the number of sub-domains will be possessed separately, then several equations are developed to show the relationships. Using the equations, some phenomena in ddP–dOM can be made clear easily. At the same time, the correctness of the equations is verified.

关键词： iteration decompose steps processors directions verified latter partition rectangular split

Novel high-voltage, high-side and low-side power devices with a single control signal

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Journal of Semiconductors 2013年第9期34卷 73-77页

作者：孔谋夫陈星弼 State Key Laboratory of Electronic Thin Films and Integrated devices University of Electronic Science and Technology of China

Novel high-voltage, high-side and low-side power devices, whose control circuits are referred to as the tub, are proposed and investigated to reduce chip area and improve the reliability of high-voltage integrated circuits. By using the tub circuit to control a branch circuit consisting of a PMOS and a resistor, a pulse signal is generated to control the low-side n-LdMOS after being processed by a low-voltage circuit. Thus, the high-voltage level-shifting circuit is not needed any more, and the parasitic effect of the conventional level-shifting circuit is eliminated. Moreover, the specific on-resistance of the proposed low-side device is reduced by more than 14.3% compared with the conventional one. In the meantime, integrated low-voltage power supplies for the low-voltage circuit and the tub circuit are also proposed. Simulations are performed with MEdICI and SPICE, and the results show that the expectant functions are achieved well.

关键词： power devices LdMOS pulse signal low-voltage power supply

OPTIMAL ERROR ESTIMATES OF A dECOUPLEd SCHEME BASEd ON TWO-GRId FINITE ELEMENT FOR MIXEd NAVIER-STOKES/dARCY MOdEL

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Acta Mathematica Scientia 2018年第4期38卷 1361-1369页

作者： Wi QIN Wanren HOU School of Mathematics and Statistics Xi＇an Jiaotong UniversityXi＇an 710049China

Although the two-grid finite element decoupled scheme for mixed Navier-Stokes/ darcy model in literatures has given the numerical results of optimal convergence order, the theoretical analysis only obtain the optimal error order for the porous media flow and a non-optimal error order for the fluid flow. In this article, we give a more rigorous of the error analysis for the fluid flow and obtain the optimal error estimates of the velocity and the pressure.

关键词： Navier-Stokes equation darcy's law two-grid method optimal error estimate

phase diagram of Transverse Spin-2 Ising Model with Longitudinal Crystal Field

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Communications in Theoretical physics 2009年第7期52卷 163-167页

作者： ZHAO Jie XU Xing-Guang WEI Guo-Zhu School of Science Liaoning Sbihua University Fushun 113001 China School of Science Northeastern University Shengyang 110006 China

The transverse spin-2 Ising ferromagnetic model with a longitudinal crystal field is studied within themean-field *** phase diagrams and magnetization curves are obtained by diagonalizing the Hamiltonian H_i ofthe Ising system numerically,and the first order-order phase transitions,the first order-disorder phase transitions,andthe second-order phase transitions are discussed in *** phenomena occur when the value of the transversefield is not zero and the reentrant diagram is given.

关键词： transverse spin-2 Ising model phase diagram first order-order phase transition reentrant phenomenon

Threshold characteristic of intracavity optical parametric oscillator pumped by all-solid-state Q-switched laser

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Chinese Optics Letters 2008年第3期6卷 207-210页

作者：王与烨徐德刚于意仲温午麒李喜福姚建铨 College of Precision Instrument and Optoelectronics Engineering Institute of Laser and Optoelectronics Tianjin University School of Electrical Engineering and Automation Tianjin University

We derive the threshold pump intensity for a singly resonant intracavity optical parametric oscillator （IOPO） based on a temporal coupled field model. Particular attention is paid to the dependence of the intracavity singly resonant OPO （SRO） threshold intensity on the signal wave output coupling. Meanwhile, a Nd：YAG laser pumped KTiOPO4 （KTP） IOPO for eye-safe laser output is studied experimentally. The experiment is performed with four signal wave output reflectivities of 60%, 70%, 80%, and 90%, respectively. The measured values are in good agreement with the theoretical results. With an output coupler reflectivity of 80%, a peak power of 70 kW at 1572 nm has been obtained at a repetition rate of 3.5 kHz. The pulse width is 4.9 ns. Such investigation is helpful to identifying suitable operational regime of low pump intensity.

关键词： Light reflection Q switched lasers Solid state lasers

Protective effects of ciliary neurotrophic factor on the retinal ganglion cells by injure of hydrogen peroxide

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International Journal of Ophthalmology(English edition) 2018年第6期11卷 923-928页

作者： Wen-Jun Wang Wei Jin An-Huai Yang Zhen Chen Yi-Qiao Xing Eye Center Renmin Hospital of Wuhan University

AIM： To explore the effect of ciliary neurotrophic factor （CNTF） on retinal ganglion cell （RGC）-5 induced by hydrogen peroxide （H2O2）. METHOdS： After cell adherence, RGC-5 culture medium was changed to contain different concentrations of H2O2 from 50 to 150 μmol/L at four time points （0.5, 1, 1.5 and 2h） to select the concentration and time point for H2O2 induced model. Two different ways of interventions for injured RGC-5 cells respectively were CNTF as an addition in the culture medium or recombinant lentiviral plasmid carrying CNTF gene transfecting bone mesenchymal stem cells （BMSCs） for co-culture with RGC-5. RESULTS： Compared to the control group, H2O2 led to RGC-5 death closely associated with concentrations and action time of H2O2 and we chose 125 μmol/L and 2h to establish the H2O2-induced model. While CNTF inhibited the loss of RGC-5 cells obviously with a dose-dependent survival rate. Nevertheless two administration routes had different survival rate yet higher rate in recombinant lentiviral plasmid group but there were no statistically significant differences. CONCLUSION： Both the two administration routes of CNTF have effects on RGC-5 cells induced by H2O2. If their own advantages were combined, there may be a better administration route.

关键词： retinal ganglion cells ciliary neurotrophic factor hydrogen peroxide neuroprotection recombinant lentiviral vector

Cementation of sand grains based on carbonate precipitation induced by microorganism

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Science china(Technological Sciences) 2010年第8期53卷 2198-2206页

作者： QIAN ChunXiang,PAN QingFeng &WANG RuiXing Jiangsu Key Laboratory of Construction Materials,School of Materials Science&Engineering,Southeast University,Nanjing 211189,china 1. Jiangsu Key Laboratory of Construction Materials School of Materials Science & Engineering Southeast University Nanjing 211189 China

Microbes can produce 2 3 CO32-in an environment conductive to precipitation,so the incompact sands will be *** technology is environmentally friendly not only because it gives strength to the sand body,but also it allows water to penetrate into the sand body,which is unlike silicate cement that will destroy the ecosystem of the *** comparing the activity of three kinds of bacteria,the most suitable one was chosen for the ***,the activity of this bacterium was still not high enough for the purpose,so it was purified.A suitable program for the consolidation and cementation of sands was also found in the *** compressive strength and the porosity of the cemented sand body were tested to characterize the cementation *** analysis showed that a new phase of calcite was produced between sand *** content of calcite was detected by *** study showed that the precipitation program was quite important to obtain a sound cemented sand body in addition to the activity of the bacteria.

关键词： carbonate precipitation microbe calcite sand consolidation porosity compressive strength

Recent advances in cell imaging and cytotoxicity of intracellular stimuli-responsive nanomaterials

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Science Bulletin 2015年第23期60卷 1973-1979页

作者： Wenbo Zhang Changyou Gao ministry of education Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and Engineering Zhejiang University

The stimuli-responsive nanomaterials are gaining more and more interest in the biological field,including cell imaging and biosensing etc. Nanomaterials in response to the bio-relevant stimuli(i.e., p H, enzymes and other bioactive molecules) can be utilized to enhance imaging(i.e., optical imaging, MRI, and multi-mode imaging) sensitivity via disease site-specific delivery and controlled release, which helps to diagnose cancer at an early stage or to monitor progression during treatment. In the triggered responsive process, smart nanomaterials undergo changes in physiochemical properties that can cause cytotoxicity or influence on cell functions due to the interactions between nanomaterials and cells. In order to promote the design and fabrication of effective platforms for therapeutics and diagnostics, special attention should be paid to these effects. By taking the advantages of intracellular stimuli, the controlled self-assembly in living cells can be achieved, which has been used for various in situ detections and insights into biological self-assembly. In this review, the recent advances in cell imaging, cytotoxicity and self-assembly of intracellular stimuli-responsive nanomaterials are summarized. Some principles for the further design and applications of intracellular stimuli-responsive nanomaterials and future perspectives are discussed.

关键词： Stimuli-responsive · Nanomaterials ·Cell imaging · Cytotoxicity · Self-assembly