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Electron Spin Pairing and the Phase Diagram of High-Tc Superconductors

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Chinese Physics Letters 2001年第10期18卷 1398-1400页

作者： guo Wei HAN Ru-shan Department of Physics Peking UniversityBeijing 100871

The origin of the instability of the normal state of electrons in the superconducting copper oxides is shown by the K-J model, in which the superexchange (K) between local moments and the Kondo exchange ( J) between electron and local moment are considered. The suppression of superexchange via impurity doping may induce effective spin coupling between electrons and triplet pairing (S = 1, Sz = 0). The spin pairing theory explains the phase diagram of high-To superconductors, especially the superconducting transition temperature Tc, the pseudogap temperature T^(*) and the magnetic crossover temperature Tn as a function of the doped hole concentration. The universal expression for the empirical law of the superconducting transition temperature is derived from the theory.

关键词： theory exchange Electron

Gonadotropin-releasing hormone positively regulates steroidogenesis via extracellular signal-regulated kinase in rat Leydig cells

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Asian Journal of Andrology 2011年第3期13卷 438-445,512页

作者： Bing Yao Hai-Yan Liu Yu-Chun Gu shan-shan Shi xiao-Qian Tao xiao-Jun Li Yi-Feng Ge Ying-Xia Cui guo-Bin Yang Department of Reproduction and Genetics Nanjing Jingling Hospital Nanjing 210002 China Nanjing Normal University Nanjing 210046 China Department of Physiology The Medical School University of Birmingham Edgbaston B15 2TT UK Medical Administration Division Nanjing Jingling Hospital Nanjing 210002 China

Gonadotropin-releasing hormone （GnRH） is secreted from neurons within the hypothalamus and is necessary for reproductive function in all vertebrates. GnRH is also found in organs outside of the brain and plays an important role in Leydig cell steroidogenesis in the testis. However, the signalling pathways mediating this function remain largely unknown. In this study, we investigated whether components of the mitogen-activated protein kinase （MAPK） pathways are involved in GnRH agonist （GnRHa）-induced testis steroidogenesis in rat Leydig cells. Primary cultures of rat Leydig cells were established. The expression of 3β-hydroxysteroid dehydrogenase （3β-HSD） and the production of testosterone in response to GnRHa were examined at different doses and for different durations by RT-PCR, Western blot analysis and radioimmunoassay （RIA）. The effects of GnRHa on ERK1/2, JNK and p38 kinase activation were also investigated in the presence or absence of the MAPK inhibitor PD-98059 by Western blot analysis. GnRHa induced testosterone production and upregulated 3β-HSD expression at both the mRNA and protein levels; it also activated ERK1/2, but not JNK and p38 kinase. Although the maximum effects of GnRHa were observed at a concentration of 100 nmnol L-1 after 24 h, activation of ERKI/2 by GnRHa reached peak at 5 min and it returned to the basal level within 60 min. PD-98059 completely blocked the activation of ERKI/2, the upregulation of 3β-HSD and testosterone production. Our data show that GnRH positively regulates steroidogenesis via ERK signalling in rat Leydig cells. ERK1/2 activation by GnRH may be responsible for the induction of 3β-HSDgene expression and enzyme production, which may ultimately modulate steroidogenesis in rat Leydig cells.

关键词： 3β-HSD ERK1/2 GnRH JNK Leydig cell p38

Ionizing and non-ionizing kerma factors in silicon for China Spallation Neutron Source neutron spectrum

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Nuclear Science and Techniques 2019年第9期30卷 119-125页

作者： xiao-Ming Jin Yan Liu Chun-Lei Su Wei Chen Chen-hui Wang shan-Chao Yang xiao-Qiang guo State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear Technology

The quantification of ionizing energy deposition and non-ionizing energy deposition plays a critical role in precision neutron dosimetry and in the separation of the displacement damage effects and ionizing effects induced by neutron radiation on semiconductor devices. In this report, neutrons generated by the newly built China Spallation Neutron Source (CSNS) are simulated by Geant4 in semiconductor material silicon to calculate the ionizing and non-ionizing kerma factors. Furthermore, the integral method is applied to calculate neutron-induced ionizing at the CSNS and non-ionizing kerma factors according to the standard neutron nuclear database and the incident neutron spectrum. In addition, thermoluminescence dosimeters are utilized to measure the ionizing energy deposition and six series of bipolar junction transistors are used to measure the non-ionizing energy deposition based on their neutron damage constants. The calibrated kerma factors that were experimentally measured agreed well with the simulation and integral calculation results. This report describes a complete set of methods and fundamental data for the analysis of neutron-induced radiation effects at the CSNS on silicon-based semiconductor devices.

关键词： Neutron radiation Kerma Ionizing energy Non-ionizing energy CSNS

Chemical Composition and Biological Activities of Essential Oil from the Rhizomes of Iris bulleyana

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Agricultural Sciences in China 2009年第6期8卷 691-696页

作者： DENG guo-bin ZHANG Han-bo XUE Hong-fen CHEN shan-na CHEN xiao-lan Department of Biology Yunnan University Kunming 650091 P.R.China

Iris bulleyana has long been used as a remedy for detoxication and detumescence. Hydrodistillation was used to extract the essential oil from its rhizomes, and 0.23% oil yield was obtained. Using gas chromatography-mass spectrometry （GC- MS） analysis, 31 chemicals including aristolone, cuparene, β-gurjunene, δ-amorphene, α-muurolene, α-cadinol, camphor, γ-elemene, and τ-cadinol were identified. The essential oil exhibited antibacterial activity against Acetobacter calcoacetica, Bacillus subtillis, Clostridium sporogenes, Clostridium perfringens, Escherichia coli, Salmonella typhii, Staphylococcus aureus, and Yersinia enterocolitica. Its antifungal and antioxidant activities were also tested.

关键词： Iris bulleyana essential oil antibacterial antifungal antioxidant GC-MS chemical components

Direct trajectory optimization based on a mapped Chebyshev pseudospectral method

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Chinese Journal of Aeronautics 2013年第2期26卷 401-412页

作者： guo xiao Zhu Ming School of Aeronautic Science and Engineering Beihang University

In view of generating optimal trajectories of Bolza problems, standard Chebyshev pseudospectral （PS） method makes the points＇ accumulation near the extremities and rarefaction of nodes close to the center of interval, which causes an ill-condition of differentiation matrix and an oscillation of the optimal solution. For improvement upon the difficulties, a mapped Chebyshev pseudospectral method is proposed. A conformal map is applied to Chebyshev points to move the points closer to equidistant nodes. Condition number and spectral radius of differentiation matrices from both methods are presented to show the improvement. Furthermore, the modification keeps the Chebyshev pseudospectral method＇s advantage, the spectral convergence rate. Based on three numerical examples, a comparison of the execution time, convergence and accuracy is presented among the standard Chebyshev pseudospectral method, other collocation methods and the proposed one. In one example, the error of results from mapped Chebyshev pseudospectral method is reduced to 5% of that from standard Chebyshev pseudospectral method.

关键词： Chebyshev approximation Conformal shift Interpolation Optimization Pseudospectral method Trajectory

Compactness of Extremals for Trudinger-Moser Functionals on the Unit Ball in R^(2)

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Acta Mathematica Sinica,English Series 2024年第11期40卷 2840-2854页

作者： Wei Wei shan xiao Meng LI School of Mathematical Sciences Huaibei Normal UniversityHuaibei235000P.R.China School of Mathematics and Big Data Chaohu UniversityHefei230000P.R.China

Let B be a unit ball in R^(2),W_(0)^(1,2)(B)be the standard Sobolev *** anyϵ>0,de Figueiredo,doÓ,dos Santons,Yang and Zhu proved the existence of extremals of a Trudinger-Moser inequality in the unit ***,u∈W_(0)^(1,2)(B)^(sup),∫_(B)|▽u|^(2)dx≤1∫_(B)^(|x|^(2∈)e^(4π(1+∈)u^(2)dx)can be attained by some radially symmetric function u_(∈)∈W_(0)^(1,2)(B)∫_(B)with∫_(B)|▽u|^(2)dx=*** this note,we concern the compactness of the function family{uϵ}ϵ>0 and prove that up to a subsequence uϵconverges to some function u 0 in C^(1)(B)asϵ→***,u_(0) is an extremal function of the supremum u∈W_(0)^(1,2)(B)^(sup),∫_(B)|▽u|^(2)dx≤1∫_(B)e^(4πu^(2)dx)Let us explain the result in ***ω_(0)=dx_(1)^(2)+dx_(2)^(2)be the standard Euclidean metricω_(∈)|x|^(2ϵ)ω_(0)for xϵB..Then the extremal family{u_(∈)}∈>0 of the following Trudinger-Moser functionals∫_(B)e^(4π(1+∈)u^(2))dvω_(∈)under the constraint W_(0)^(1,2)(B)and∫_(B)|▽ω_∈)u|^(2)dvω_∈)≤1 is compact asϵ→0.

关键词： Trudinger-Moser inequality extremal function blow-up analysis compactness

A covalent modified hydrophilic capillary for enhanced capillary electrophoresis of biopolymers

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Chinese Chemical Letters 2009年第9期20卷 1123-1126页

作者： Lian guo shan Xue Yu Yin Mao Wei xiao Hui Zheng Jian Bin Zheng College of Chemistry and Materials Science Northwest University Xi'an 710069 China Institute of Analytical Science Northwest University Xi'an 710069 China

8-Gluconolactone was covalently coupled to aminopropyl derivatized capillary, which created hydrophilic brushes on the inner wall of the capillary. The coated capillary was shown to generate a stable electroosmotic flow （EOF） in the investigated pH range of 2.0-9.0 and to suppress effectively the adsorption of proteins. And it enabled separation of some biopolymer mixtures including basic proteins, DNA and tryptic digested bovine serum albumin （BSA） within 15 rain with efficiencies up to 450,000 plates/m. The intra- and inter-day reproducibility of the coating referring to the retention times of proteins were satisfactory with mean relative standard deviations （R.S.D.） of 0.8 and 1.7%, respectively. 2009 Yin Mao Wei. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All fights reserved.

关键词： Capillary electrophoresis Capillary coating 8-Gluconolactone Protein separation

A simple approach for determining the preload of a wire race ball bearing

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第7期11卷 511-519页

作者： xiao-biao shan Li-li WANG Tao XIE Wei-shan CHEN 1School of Mechatronics Engineering Harbin Institute of Technology Harbin 150001 China College of Science Northeast Forestry University Harbin 150040 China

Wire race ball bearings have been widely used in high-tech weapons. The preload of a wire race ball bearing is crucial in engineering applications. In this study, a more effective approach is proposed for exact determination of the wire race ball bearing preload. A new mathematical model of the preload and the starting torque of the wire race ball bearing was built using the theorem of the 3D rolling friction resistance and the non-conforming contact theory. Employing a wire race ball bearing with a 1000 mm diameter used in a specific type of aircraft simulating rotary table, the numerical analysis in MATLAB～ showed that the preload magnitude can be controlled in the range of 130–140 μm. As verification, the experimental results were in agreement with the theoretical results, and confirm the feasibility of this method. This new approach is more exact in the preload range of 10–158 μm than that computed by the numerical method reported in our previous work (shan et al., 2007b). This implies that the present method contributes to more effectively preventing rolling noise, overturning moments and wear of the wire race ball bearing. The current research provides critical technical support for the engineering application of wire race ball bearings with large diameters.

关键词： Wire race ball bearing Rolling friction Starting torque Contact interface

Resonant frequencies of a piezoelectric drum transducer

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第9期10卷 1313-1319页

作者： Jiang-bo YUAN Tao XIE xiao-biao shan Wei-shan CHEN State Key Laboratory of Advanced Robot and System Harbin Institute of Technology Harbin 150001 China

This paper presents a piezoelectric-metal structure called a drum transducer. An equation for calculating the resonance frequency of the drum transducer is obtained based on thin plate elastic theory of piezoelectric and metal material combined with the Rayleigh-Ritz method. The finite element method (FEM) was used to predict the excitation frequency of the drum transducer. To verify the theoretical analysis, the input impedance characteristic of the drum transducer was measured using an experimental method. The results obtained from theoretical analysis were in very good agreement with those from the FEM and experimental results. The effect of geometrical changes to the thick-walled steel ring of the drum transducer at the first resonance frequency is also described. The calculated results were found to be in good agreement with the FEM results. The results indicate that the first resonance frequency of the drum decreases with the increasing inner diameter of the thick-walled steel ring.

关键词： Piezoelectric Drum transducer Resonance frequency