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Dwell Time of Particles in Tunneling Barriers of Arbitrary Shape

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chinese Physics Letters 1998年第12期15卷 862-864页

作者： BAI er-juan SHU Qi-qing Institute of Applied Nuclear Technology Shenzhen UniversityShenzhen 518060 School of Science Shenzhen UniversityShenzhen 518060

For a one-dimensional barrier of arbitrary shape,an expression of the dwell time of tunneling particles has been obtained by subdividing it into infinitesimal rectangular barrier elements and then summing the dwell times spent by particles inside the barrier elements,and the dwell times in a parabolic potential barrier were *** results show that the dwell times are almost independent of the barrier width as it is greater than a characteristic width *** can be ascribed that in the width range beyond Wc,the tunneling probabilities through the barrier elements are very small,thus the times taken to tunnel through them make little contribution to the summation of the dwell times in all the barrier elements.

关键词： barrier tunneling beyond

conversion of water consumption of a single tree and a forest stand of Populus euphratica

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Forestry Studies in china 2008年第2期10卷 81-87页

作者： KANG er-si cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences

Our study dealt with the determination of sapwood sap flow of a single Populus euphratica tree by heat pulse technique and the calculation of water consumption of an entire forest stand, given the correlation between sap flow and sapwood area of P. euphratica. The relation between diameter at breast height （DBH） and sapwood area constitutes a powerful model; these variables are highly correlated. By means of an analysis of DBH in the sample plot, the distribution of the sapwood area of the forest land was obtained and the water consumption of this P. euphratica forest, in the lower reaches of the Heihe River, calculated as 214.9 mm by standard specific conductivity of the sample tree.

关键词： Populus euphratica sap flow water consumption

Interaction between Janus Green B and bovine serum albumin:Electrochemistry and spectroscopy studies

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chinese chemical Letters 2011年第6期22卷 717-720页

作者： Neslihan zdemir Serkan zdemir Ender Bier Ondokuz Mayrs University Faculty of Arts and Sciences Department of Chemistry

In this study,voltammetric and spectroscopic investigation of the interaction between Janus Green B（JGB） and bovine serum albumin（BSA） was *** interaction was observed at Britton-Robinson buffer（pH 7.0）.When JGB was added to solution containing BSA,the peak currents of BSA decrease with the increasing of JGB concentrations which is due to the interaction of JGB and *** binding constant of JGB with BSA was obtained by voltammetric ***,this interaction was supported by means of UV-vis spectroscopic *** UV-vis absorption spectra of JGB in the presence of BSA decrease with the increasing of BSA concentrations.

关键词： Voltammetry Bovine serum albumin Janus Green B Interaction

Lagrangian Bonnet Problems in complex Space Forms

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Acta Mathematica Sinica,English Series 2019年第8期35卷 1357-1366页

作者： Hui Xia HE Hui MA er Xiao WANG School of Mathematics and Systems Science Beihang University LIMB of the Ministry of Education Beijing 100083 P. R. China Department of Mathematical Sciences Tsinghua University Beijing 100084 P. R. China Department of Mathematics Hong Kong Univ of Sci. and Tech. Clear Water Bay Kowloon Hong Kong P. R. China

In this note we consider Lagrangian Bonnet problem for Lagrangian surfaces in complex space forms. We first give a Bonnet type theorem for conformal Lagrangian surfaces in complex space forms, then we show that any compact Lagrangian surface in the complex space form admits at most one other global isometric Lagrangian surface with the same mean curvature form, unless the Maslov form is conformal. These two Lagrangian surfaces are then called Lagrangian Bonnet pairs. We also studied Lagrangian Bonnet surfaces in complex space forms, and obtain some characterizations of such surfaces.

关键词： Lagrangian submanifolds complex space forms. Bonnet pairs

The Approximate Solutions of FPK Equations in High Dimensions for Some Nonlinear Stochastic Dynamic Systems

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communications in computational Physics 2011年第10期10卷 1241-1256页

作者： Guo-Kang er Vai Pan Iu Faculty of Science and Technology University of MacaoMacao SARP.R.China

The probabilistic solutions of the nonlinear stochastic dynamic(NSD)systems with polynomial type of nonlinearity are investigated with the subspace-EPc *** space of the state variables of large-scale nonlinear stochastic dynamic system excited by white noises is separated into two *** sides of the Fokker-Planck-Kolmogorov(FPK)equation corresponding to the NSD system is then integrated over one of the *** FPK equation for the joint probability density function of the state variables in another subspace is ***,the FPK equation in low dimensions is obtained from the original FPK equation in high dimensions and it makes the problem of obtaining the probabilistic solutions of largescale NSD systems solvable with the exponential polynomial closure *** about the NSD systems with polynomial type of nonlinearity are given to show the effectiveness of the subspace-EPc method in these cases.

关键词： Nonlinear stochastic dynamic systems large-scale systems probability density function Fokker-Planck-Kolmogorov equation subspace

Nowhere-zero 15-Flow in 3-Edge-connected Bidirected Graphs

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Acta Mathematica Sinica,English Series 2014年第4期30卷 649-660页

作者： er Ling WEI Wen Liang TANG Dong YE Department of Mathematics Renmin University of China Department of Mathematics West Virginia University Department of Mathematical Sciences Middle Tennessee State University

It was conjectured by Bouchet that every bidirected graph which admits a nowhere-zero κ flow will admit a nowhere-zero 6-flow. He proved that the conjecture is true when 6 is replaced by 216. Zyka improved the result with 6 replaced by 30. Xu and Zhang showed that the conjecture is true for 6-edge-connected graphs. And for 4-edge-connected graphs, Raspaud and Zhu proved it is true with 6 replaced by 4. In this paper, we show that Bouchet＇s conjecture is true with 6 replaced by 15 for 3-edge-connected graphs.

关键词： Bidirected graph integer flow signed graph

A comprehensive study of hydrogen production from ammonia borane via PdcoAg/Ac nanoparticles and anodic current in alkaline medium:experimental design with response surface methodology

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Frontiers in Energy 2020年第3期14卷 578-589页

作者： Hilal cELIK KAZIcI Sakir YILMAZ Tekin SAHAN Fikret YILDIZ Omer Faruk er Hilal KIVRAK Department of chemical Engineering Faculty of EngineeringVan Yiizuncii Yil University65080 VanTurkey

In this paper,the optimization of hydrogen(H2)production by ammonia borane(NH3BH3)over PdcoAg/Ac was investigated using the response surface ***,the electro-oxidation of NH3BH3 was determined and optimized using the same method to measure its potential use in the direct ammonium boran fuel ***,the ternary alloyed catalyst was synthesized using the chemical reduction *** synergistic effect between Pd,co and Ag plays an important role in enhancement of NH3BH3 *** addition,the support effect could also efficiently improve the catalytic ***,the effects of NH3BH3 concentration(0.1-50 mmol/5 mL),catalyst amount(1-30 mg)and temperature(20℃-50℃)on the rate of H2 production and the effects of temperature(20℃-50℃),NH3BH3 concentration(0.05-1 mol/L)and catalyst amount(0.5-5 jiL)on the electro-oxidation reaction of NH3BH3 were investigated using the central composite design experimental *** implementation of the response surface methodology resulted in the formulation of four models out of which the quadratic model was adjudged to efficiently appropriate the experimental data.A further statistical analysis of the quadratic model demonstrated the significance of the model with a pvalue far less than 0.05 for each model and coefficient of determination(R2)of 0.85 and 0.95 for H2 production rate and NH3BH3 electrroxidation peak current,respectively.

关键词： ammonia borane hydrogen production fuel cell response surface methodology

A Study of the Large Scale Flooding over Eastern china in 1755

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Advances in climate change Research 2012年第3期3卷 128-137页

作者： ZHANG De-er National climate center China Meteorological Administration Beijing 100081 China

Following disastrous flooding in several river valleys over eastern china in 1755, serious flooding occurred in the middle and lower reaches of the Yellow River in 1756 and 1757, a rarely seen precipitation pattern of north-flood and south-drought in china for two successive years. This is a serious meteorological disaster and extreme climatic event taking place under the climatic background of a warm phase of the Little Ice Age. In this paper, by means of historical literature records, the rainy and flooding situation and the weather characteristics of these years are reconstructed and the maps depicting areas of prolonged rain, flood and concomitant famine, insect pest, and pestilence are made. The results show that, in 1755, the middle and lower reaches of the Yellow River and the Yangtze River, and the Huaihe River Basin experienced a prolonged rainy season with multiple torrential rain events. The continuous rainy period exceeded 40 days in the Huang-Huai Region. An early Meiyu occurred, and the duration of the Meiyu period in the lower Yangtze River Basin was 43 days, the longest in the 18th century. Particularly in Nanjing the annual rainfall of 1755 was 1,378 mm, the highest record of the 18th century. The year of 1755 is characterized by lower temperature in summer, early frost in autumn, and heavy snowfall and freezing rain in winter. These characteristics are extremely similar to those of 1823 and 1954, two typical years of extreme rainfall. And all these three years with extreme precipitation axe corresponding to the minimum phase of the solar activity cycle.

关键词： extreme climatic event flood meteorological disaster 1755 historical climate

Effect of Different Surface Treatment Methods on the Friction and Wear Behavior of AISI 4140 Steel

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Journal of Materials Science & Technology 2010年第3期26卷 251-257页

作者： Mustafa Ulutan Osman N.celik Hakan Gasan Umit er University of Eskisehir Osmangazi Faculty of EngineeringDepartment of Mechanical Engineering University of Eskisehir Osmangazi Institute of Metallurgy

In this study,the effects of various surface treatments on the friction and wear behavior of AISI 4140 steel have been *** surfaces of AISI 4140 steel were treated by quenching,carburizing,boronizing and plasma transferred arc （PTA） *** microstructural characteristics of surface treated steel samples were examined by optical microscopy and scanning electron microscopy （SEM）.The mechanical properties of the samples including the surface roughness,microhardness,and abrasive and adhesive wear characteristics were also *** tests were applied by using a block-on-disc configuration under dry sliding *** wear behavior and friction characteristics of the samples were determined as a function of sliding *** sample group was compared with the other sample groups,and it was observed that the carburized samples demonstrated the lowest weight losses;however,PTA-treated samples demonstrated the lowest coefficient of friction in comparison to the other sample groups at the same sliding distance.

关键词： AISI 4140 steel Quenching Boronizing Plasma transferred arc (PTA) carburizing Sliding wear