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A computer simulation of nucleation and growth of thin films

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science china(Physics,Mechanics & Astronomy) 2004年第4期47卷 442-451页

作者： ZHENG Xiaoping1,ZHANG Peifeng2,HE Deyan2,LIU Jun2& MA Jiantai3 1. Key Laboratory of Opto-Electronic technology and Intelligent Control, Ministry of Education, lanzhou Jiaotong university, lanzhou 730070, china 2. school of Physical science and technology, lanzhou university, lanzhou 73.000, china 3. school of Chemistry and Chemistry Engineering, lanzhou university, lanzhou 73.000, china 1. Key Laboratory of Opto-Electronic technology and Intelligent Control Ministry of Education Lanzhou Jiaotong University 730070 Lanzhou China 2. school of Physical science and technology Lanzhou University 730000 Lanzhou China 3. school of Chemistry and Chemistry Engineering Lanzhou University 730000 Lanzhou China

A three-dimensional kinetic Monte Carlo technique has been developed for simulating the nucleation and growth of thin films. This model involves incident atom attachment, surface diffusion of the atoms on the growing surface and atom detachment from the growing surface. It takes some new effects into account, such as a significant improvement in calculation of activation energy for the atom diffusion, which renders the model more reasonable. In addition three optimum temperatures and the consistency of their dependence on deposition rate have been found out; the dependence of the surface roughness and relative density on the deposition rate has been discussed; and the approximation of freezing neighbour atoms and periodic boundary conditions has been applied.

关键词： Monte Carlo, thin film, nucleation, surface roughness, relative density.

Effect of pH,fulvic acid and temperature on the sorption of uranyl on ZrP_2O_7

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science china Chemistry 2010年第6期53卷 1429-1437页

作者： QIAN LiJuan,HU PeiZhuo,JIANG ZhenJiang,GENG YanXia & WU WangSuo Radiochemistry Laboratory,school of nuclear science and technology,lanzhou university,lanzhou 73000,china 1. Radiochemistry Laboratory School of Nuclear Science and Technology Lanzhou University Lanzhou 73000 China

The sorption of UO22+ onto ZrP2O7 was studied using the batch technique and the point of zero charge of ZrP2O7 was obtained through mass *** results indicated that sorption of UO22+ onto ZrP2O7 was strongly affected by pH,solid-to-liquid ratio (m/V),the species of electrolyte in solution and fulvic acid (FA),but was insensitive to ionic *** sorption of UO22+ increased with increasing pH and m/*** presence of FA enhanced UO22+ sorption onto ZrP2O7 at low *** presence of phosphate or sulfate caused opposite effects on the sorption of UO22+ onto *** of citrate also significantly affected UO22+ *** sorption of UO22+ increased as the temperature of the system *** Langmuir and Freundlich models were used to simulate the sorption isotherms of UO22+ onto ZrP2O7 at different *** results indicated that the Freundlich model described UO22+ sorption better than the Langmuir *** parameters for the sorption process were calculated from the temperature dependent sorption *** results suggested that the sorption process of UO22+ onto ZrP2O7 is spontaneous and *** desorption process of UO22+ from ZrP2O7 was also investigated and it was found that sorption onto ZrP2O7 was irreversible.

关键词： ZrP2O7 uranyl sorption desorption thermodynamic data

Robustness and breakup of the spiral wave in a two-dimensional lattice network of neurons

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science china(Physics,Mechanics & Astronomy) 2010年第4期53卷 672-679页

作者： MA Jun 1,2, TANG Jun 2 , ZHANG AiHua 3 & JIA Ya 2 1 Department of Physics, lanzhou university of technology, lanzhou 730050, china 2 Department of Physics, Central china Normal university, Wuhan 430079, china 3 College of Electrical and Information Engineering, lanzhou university of technology, lanzhou 730050, china 1. Department of Physics Lanzhou University of Technology Lanzhou 730050 China2. Department of Physics Central China Normal University Wuhan 430079 China3. College of Electrical and Information Engineering Lanzhou University of Technology Lanzhou 730050 China

The robustness and breakup of spiral wave in a two-dimensional lattice networks of neurons are investigated. The effect of small- world type connection is often simplified with local regular connection and the long-range connection with certain probability. The network effect on the development of spiral wave can be better described by local regular connection and changeable long-range connection probability than fixed long-range connection probability because the long-range probability could be changeable in realistic biological system. The effect from the changeable probability for long-range connection is simplified by multiplicative noise. At first, a stable rotating spiral wave is developed by using appropriate initial values, parameters and no-flux boundary conditions, and then the effect of networks is investigated. Extensive numerical studies show that spiral wave keeps its alive and robust when the intensity of multiplicative noise is below a certain threshold, otherwise, the breakup of spiral wave occurs. A statistical factor of synchronization in two-dimensional array is defined to study the phase transition of spiral wave by checking the membrane potentials of all neurons corresponding to the critical parameters(the intensity of noise or forcing current)in the curve for factor of synchronization. The Hindmarsh-Rose model is investigated, the Hodgkin-Huxley neuron model in the presence of the channel noise is also studied to check the model independence of our conclusions. And it is found that breakup of spiral wave is easier to be induced by the multiplicative noise in presence of channel noise.

关键词： spiral wave factor of synchronization breakup multiplicative noise robustness

Predictions of synthesizing element 119 and 120

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science china(Physics,Mechanics & Astronomy) 2011年第S1期54卷 61-66页

作者： GAN ZaiGuo1, ZHOU XiaoHong1, HUANG MingHui1, FENG ZhaoQing1 & LI JunQing1,2 1Institute of Modern Physics, Chinese Academy of sciences, lanzhou 73.000, china 2school of nuclear science and technology, lanzhou university, lanzhou 73.000, china Chinese Acad Sci Inst Modern Phys Lanzhou 730000 Peoples R China lanzhou Univ Sch Nucl Sci & Technol Lanzhou 730000 Peoples R China

The evaporation residue cross sections of synthesizing superheavy nuclei Z=119, 120 are calculated by different sets of master equations with different dynamical variables. Two methods basically predicted similar results that the Ca induced hot fusion can 48 produce element 119 easier than produce 120, and the evaporation residue cross sections for 119 are detectable by current advanced techniques, while the evaporation residue cross sections are below 0.1 pb for producing element 120.

关键词： super heavy nuclei evaporation residue cross section master equations

Improvements on radiation-hardened performance of static induction transistor

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science china(Information sciences) 2010年第5期53卷 1089-1096页

作者： WANG YongShun 1 , LUO XianLiang 1 , LI HaiRong 2 , WANG ZiTing 1 , WU Rong 1 , ZHANG CaiZhen 2 & LI SiYuan 2 1 school of Electronic and Information Engineering, lanzhou Jiaotong university, lanzhou 730070, china 2 Institute of Microelectronics, school of Physical science and technology, lanzhou university, lanzhou 73.000, china 1. school of Electronic and Information Engineering Lanzhou Jiaotong University Lanzhou 730070 China2. Institute of Microelectronics School of Physical Science and Technology Lanzhou University Lanzhou 730000 China

The radiation-hardened performances of static induction transistor (SIT) have been studied in depth in this paper. The effects of radiation of electron beam on the I-V characteristics, carrier distribution and potential distribution in the channel of SIT have been represented. A large number of electron-hole pairs are generated in the depletion region of reversely biased gate-channel PN junction. The radiation-generated electrons drift towards the drain region at high positive potential, while generated holes flow into gate region biased to the lowest potential. With the accumulation of holes in gate region, the gate potential is boosted, resulting in a decrease in the height of potential barrier in channel, and an increase in drain current. I-V characteristics of SIT in the presence of radiation have been theoretically derived, and compared with experimental results. With the increase in thickness of epitaxial layer, the radiation-hardened capability of SIT is continuously improved until the optimum thickness of 26 μm is reached. The optimum matching relationship among geometric, material and technological parameters has been represented to acquire excellent radiation-hardened performances of SIT.

关键词： static induction transistor radiation-resistant potential barrier electron beam radiationgenerated carriers

The time and energy signals,counter plateau,energy resolution and gas gains performances of a new kind of micro-pattern gaseous detector-Micromegas

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science china(Technological sciences) 2008年第12期51卷 2208-2212页

作者： ZHANG XiaoDong1,2,YANG HeRun1,XU HuShan2,DUAN LiMin2,HU BiTao1,LI ChunYan2 & LI ZuYu2 1 school of nuclear science and technology,lanzhou university,lanzhou 73.000,china 2 Institute of Modern Physics,Chinese Academy of sciences,lanzhou 73.000,china school of nuclear science and technology Lanzhou University Lanzhou 730000 China Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China

In present paper,a new Micromegas detector is developed,and its time and energy signals are obtained in the figure *** rising time of fast time signal is less than 2 ns due to the very fast collection of avalanche electrons,and the rising time of the energy pulse is about 100 ns,which is corresponding to the total collecting time of the electrons and ions in the avalanche *** counter plateau,energy resolution and the gas gains of the detector have been compared with other groups' experimental results and the Garfield simulation result.

关键词： micro-mesh gaseous structure time and energy signals energy resolution gas gain counter plateau

Two types of changes in apparent resistivity in earthquake prediction

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science china Earth sciences 2011年第1期54卷 145-156页

作者： DU XueBin1,2 1lanzhou Institute of Seismology, china Earthquake Administration, lanzhou 73.000, china 2lanzhou Base of Earthquake science Institute, china Earthquake Administration, lanzhou 73.000, china 1. lanzhou Institute of Seismology China Earthquake Administration Lanzhou 730000 China2. Lanzhou Base of Earthquake Science Institute China Earthquake Administration Lanzhou 730000 China

Two types of changes in apparent resistivity (AR) have been linked to earthquake occurrences. This paper studies the changes and their causes, in detail with the ultimate purpose of developing and assessing a method of earthquake (EQ) prediction. The AR changes of the first type (CFT) are considered to be precursors related to earthquakes (EQs); these appear mostly in the medium-term period before EQs and in the short-term period preceding EQs. The changes of the second type (CST) are characterized by a turning anomaly of a long-trend AR variation or the drastically descending/ascending anomaly superimposed on such a variation; these appear synchronously in large areas, such as the Chinese mainland, and northern and northwestern china, ect. Their spatio-temporal clusters correspond well to high seismicities in the areas and distant great EQs around the Chinese mainland. Based on the behaviors of the two types of changes, the AR changes observed prior to the Ms8.0 Wenchuan EQ of 2008 are studied. The results show that in the medium-term period before the EQ, noticeable anomalies appeared synchronously at four stations around the Songpan-Ganzi active block, but only weak upward changes were observed in the short-term period preceding the EQ, which caused the prediction of the imminent EQ to fail.

关键词： strong earthquake apparent resistivity two types of changes spatio-temporal cluster Wenchuan earthquake

Characteristics and origins of primary fluids and noble gases in mantle-derived minerals from the Yishu area,Shandong Province,china

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science china Earth sciences 2006年第1期49卷 77-87页

作者： MA Jinlong1,2, TAO Mingxin2,3 & YE Xianren2 1. Resources and Environmental school, lanzhou university, lanzhou 73.000, china 2. Key Laboratory of Gas Geochemistry, Institute of Geology and Geophysics, Chinese Academy of sciences, lanzhou 73.000, china 3. College of Resources science & technology, Beijing Normal university, Beijing 100875, china 1. Resources and Environmental school Lanzhou University Lanzhou 730000 China 2. Key Laboratory of Gas Geochemistry Institute of Geology and Geophysics Chinese Academy of Sciences Lanzhou 730000 China 3. College of Resources science & technology Beijing Normal University Beijing 100875 China

Fluids and noble gases of mantle-derived materials are important tracers forthe mantle information. Compositions of primary fluids and noble gases in mantle-derived mineralsfrom the Yishu area, Shandong Province, china, were tested by the methods of heat-bursting andheat-melting respectively. The fluids are mainly composed of CO_2, CO and H_2, which account forabout 90% of the total, and are similar to the mantle-derived rocks from other areas of easternchina; ratios of ~3He/~4He in almost all samples range from 0.82 Ra to 2.74 Ra, whereas^(40)Ar/^(36)Ar from 299.5 to 758.8. Both ranges are much lower than those of the typical oceanmantle-derived samples (such as MORB) and primarily reflect the influences of the atmosphericcomponents and the radiogenic isotopes. Ratios of C/~3He range from 27.6 x 10~9 to 1050 x 10~9,N_2/Ar from 927 to 56612, and N_2/~3He from 2.5 x 10~9 to 27 x 10~9, similar to those in westernUnited States and New Zealand which belong to the tectonic plate collision regions. The ratios fallin the intersect of mantle-crust-atmosphere in the comprehensive tracer-charts, reflecting theinfluences of the atmosphere and the crusts with organic components. Our results suggest that thecomposition of the primary fluids and the isotopic ratios of the noble gases may either reflect theevolution process of mantle-derived rocks connected with the rise and eruption of magma, or theinfluence of the ancient subduction-plate on the continental mantle of this region.

关键词： noble gases, primary fluids, mantle-derived minerals, Yishu area.

Topological chirality and achirality of the closed circular DNAs

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Chinese science Bulletin 1997年第20期42卷 1705-1708页

作者： QIU Wenyuan and XIN Houwen1. Department of Chemical Physics, university of science and technology of china, Hefei 230026, china 2. Department of Chemistry, lanzhou university, lanzhou 73.000, china Depaitment of Chemical Physics University of Science and Technology of China Hefei 230026 China

THE study of the relations between the topological structure and its function is one of the focus-es in modern chemistry and life science. In this note we set up a topological model to de-scribe the ccDNAs on the basis of Seifert construction in knot theory. Our model for theccDNAs helps to determine whether a structure is topologically chiral or achiral. This is one ofthe fundamental biological problems.

关键词： DNA topology knot theory topologiesl chirality topological achirality.