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A thin-layer spectroelectrochemical study of 3,3',5,5'-tetramethylbenzidine at SnO_2.F film optically transparent electrode

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science China Chemistry 2004年第4期47卷 267-275页

作者： JIAO Kui1. YANG Tao2.& NIU Shuyan1.2.1. college of Chemistry and Molecular Engineering, Qingdao {1. of {2. and technology, Qingdao 2.6042. China 2. college of Chemistry and Chemical Engineering, Ocean {1. of China, Qingdao 2.6003, China Correspondence should be addressed to Jiao Kui 1. college of Chemistry and Molecular Engineering Qingdao University of Science and Technology 266042 Qingdao China 2. {1. of Chemistry and Chemical Engineering Ocean University of China 266003 Qingdao China

The electrooxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) is dependent on the pH value of Britton-Robinson (B-R) buffer solution. In this work, the electrooxidation behavior of TMB was investigated with a SnO2.F film optically transparent thin-layer spectroelectrochemical cell. TMB underwent one two-electron electrooxidation process in the pH range from 2.0 to < 4.0, and two successive one-electron electrooxidation processes in the pH range from 4.0 to < 7.0 in the B-R buffer solution. At pH 6.5, the electrooxidative product of TMB generated a subsequent chemical reaction to yield an azo compound. Several spectroelectrochemical techniques, such as thin-layer cyclic voltammetry, thin-layer cyclic voltabsorptometry, thin-layer potential-controlled electrolysis absorptometry, thin-layer single-potential-step chronoabsorptometry, thin-layer dou-ble-potential-step chronoabsorptometry, thin-layer single-potential-step open-circuit relaxation chronoabsorptometry, were applied to this investigation. The formal potential E0’ and the electron transfer number corresponding to the electrooxidation of TMB in B-R buffer solution, and the reaction rate constant of the subsequent chemical reaction were determined.

关键词： 3,3′,5,5′-tetramethylbenzidine tin oxide film optically transparent electrode thin-layer spectroelectro-chemistry electrooxidation

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Modulation on the collective response behavior by the system size in two-dimensional coupled cell systems

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science China(Physics,Mechanics & Astronomy) 2006年第3期49卷 304-312页

作者： ZHANG Jiqian1. SHEN Chuansheng1.2.& CUI Zhifeng1.1. {1. of Physics and Electronic Information, Anhui Normal {1., Wuhu 2.1.00, China 2. Department of Educational {2., Anqing Teachers {1., Anqing 2.601., China college of Physics Electronic Information Anhui Normal University Wuhu 241000 China Department of Educational technology Anqing Teachers College Anqing 246011 China

By the intracellular calcium ionic minimal model proposed by Berridge, we investigated the collective response of two-dimensional (N×N) coupled cell systems to the external stimulation using numerical simulation methods. With a coupled intensity fixed and an appropriate coupled cell number chosen, the kinetic system size resonance was discovered. At the same time, it was found that the system size responding to the external stimulation for different coupled intensities transferred too, especially when the coupled intensity increased, the range of the corresponding system size extended. These phe- nomena illustrate that the coupled cell number and the coupled intensity can play con- structive roles in noisy coupled systems, by which the biology system would probably improve its capability to respond to the external stimulation.

关键词： cell coupling,collective response,system size resonance

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Large-scale boron nanowire nanojunctions and their highly-oriented arrays

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science China(Physics,Mechanics & Astronomy) 2004年第5期47卷 621-632页

作者： CAO Limin1.2. ZHANG Ze2.& WANG Wenkui1.2.1. Key Laboratory of Metastable Materials science and {1., Yanshan {2., Qinhuangdao 066004, China 2. Institute of Physics, Chinese Academy of sciences, beijing 1.0080, China 1. Key Laboratory of Metastable Materials science and {1. Yanshan University 066004 Qinhuangdao China 2. Institute of Physics Chinese Academy of Sciences 100080 Beijing China

Highly oriented multiple boron nanowire nanojunctions with unilateral feather- like morphology were first successfully prepared using a radio-frequency magnetron sputtering method. The branched boron nano-feathers always nucleate and grow on the same sidewall of the stems, and align in parallel to form multiple T- and/or Y-type nanojunctions. The diameters of the branches and the stems are in the range of 2.—40 and 60—80 nm, respectively. The thinner branches and thicker stems of the boron nanowires self-assembled into large-scale, highly ordered arrays on various substrates. During the formation and self-assembly of the arrays, no template or catalyst was needed. We believe that the approach presented here can be used to fabricate heterostructures with bottom-up assembly of a wide variety of one-dimensional nanostructures via the rational design of targets and the proper control of the experimental conditions.

关键词： boron nanowires, nanojunctions, self-assembly, magnetron sputtering.

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Influence of valence electron structures of phase and biphase interfaces of sulfides on hot brittleness in steel

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science China(Technological sciences) 2004年第4期47卷 488-504页

作者： LIU Yan1.3, LIU Zhilin1. ZHANG Chengwei1.2.& ZHOU Yingchun1.1. Liaoning Institute of {1., Jinzhou 1.0}001. China 2. China National Oil and Gas Exploration and Development Corporation, {1. 1.001., China 3. {2. of science, Northeastern university, Shengyang 1.0006, China 1. Liaoning Institute of technology 121001 Jinzhou China 2. {1. of {1. Northeastern University 110006 Shengyang China 3. China National Oil and Gas Exploration and Development Corporation 100011 Beijing China

This paper calculates the electron structures of phase of FeS, MnS and their biphase interface electron structures with austenite in steel. The precipitation and the transformation of FeS and MnS are investigated through studying the valence electron pair numbers on the strongest bond n A with the structure formation factor S. The continuity of electron density and its relation with stress are explored in the biphase interfaces with the electron density difference απ Using n A, S, απ we explain the reason why FeS can bring about hot brittleness in steel and the physical mechanism why MnS may eliminate or inhibit hot brittleness, based on which satisfying results are obtained by calculating several rare-earth sulfides.

关键词： valence electron structure, sulfide, hot brittleness, and rare earth.

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Synthesis and Luminescence Properties of Red Phosphor CaO:Eu^(3+)

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Journal of Wuhan university of {1.(Materials {2.) 2009年第1期24卷 20-24页

作者：康明 School of Material science and Engineering Southwest University of Science and Technology college of Materials {1. and Engineering Sichuan University

Ca（NO3）2.4H2., Eu（NO3）3 and H2.2.4·2.2. were adopted to synthesize CaO： Eu3＋ with the chemical co-precipitation method, and the effects of the calcination temperature and Eu3＋ doping concentration on the phosphor structure and its luminescent properties were investigated by TG-SDTA, XRD, and PL-PLE. The results confirm that the Eu3＋ ions as luminescent centers substi-tutes Ca2. sites without changing the crystal structure of cubic CaO. The optimum calcination tem-perature and the optimum concentration of Eu3＋ are 1.1.0 ℃ and 1.mol%, respectively, under which the best crystallinity and highest PL intensity appeared. The maximum emission wavelength is 592.nm （5D0→7F1. which is excited by xenon lamp with the wavelength of 2.0-2.0 nm, indicating that the Eu3＋ ion mainly locates in the symmetric position （Oh） in the crystal lattice of CaO.

关键词： red phosphor CaO Eu^3+ co-precipitation method rare earths

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A preliminary study on vegetation-erosion dynamics and its applications

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science China Earth sciences 2005年第5期48卷 689-700页

作者： WANG Zhaoyin 1.2., WANG Guangqian 1., LI Changzhi 1.& WANG Feixin 1.1. Department of Hydraulic Engineering, Tsinghua {1., {1. 1.0084, China 2. International Research and Training Center on Erosion and Sedimentation, {1. 1.0084, China 1. Department of Hydraulic Engineering Tsinghua University 100084 Beijing China 2. International Research and Training Center on Erosion and Sedimentation 100084 Beijing China

Vegetation-erosion dynamics is a new interdisciplinary science, studying the laws of evolution of watershed vegetation under the action of various ecological stresses. Introducing a qualitative expression of ecological stresses in this paper, the present authors establish the cou- pled differential equations for the vegetation-erosion process and derive a theoretical solution. The model is applied to the Anjiagou watershed on the Loess Pateau and the Xiaojiang water- shed and its sub-watersheds on the Yunnan Plateau. The calculated results agree well with the vegetation development processes. Abstracted from the differential equations the so-called vegetation-erosion chart is worked out, with which we can predict the development trend of vegetation under no human stresses. It is demonstrated that the erosion control is important for vegetation development and reforestation must be a long-term strategy. On the Yunnan Plateau with relatively high precipitation and temperature, vegetation can be greatly improved if erosion is controlled. On the dry and cold Loess Pateau suffering from high rate of soil erosion, however, vegetation can effectively control erosion but erosion reduction exhibits low effectiveness on vegetation development. Vegetation in the area is not stable and management is always needed to maintain the vegetation.

关键词： vegetation-erosion dynamics, human activities, coupled differential equations, erosion control, vigor ofvegetation.

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Numerical simulations of the bi-level and branched structure of intracloud lightning flashes

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science China Earth sciences 2006年第6期49卷 661-672页

作者： TAN Yongbo1, TAO Shanchang1, ZHU Baoyou1, MA Ming2.& LU Weitao2.1. School of Earth and Space sciences, {1. of science and technology of China, Hefei 2.002., China 2. Chinese Academy of Meteorological sciences, beijing 100081, China 1. School of Earth and Space sciences University of Science and Technology of China Hefei 230026 China 2. Chinese Academy of Meteorological {1.s Beijing 100081 China

Intracloud (IC) lightning flashes have been simulated in fine resolution (1.0}5 m) by using a bidirectional stochastic lightning parameterization scheme within 2.dimensional domain. The simu-lated results show that the IC flashes have a bilevel channel structure and the altitudes of the hori-zontal channels are at the same heights of potential wells, which are supported by the previous VHF source observations and balloon soundings of electric field profile in the thundercloud. Further con-clusions are: (1. After an IC flash is initiated near the boundary between positve and nagetive charge zone, the negative (or positive) leader tends to propagate into the positive (or negative) charge zone. Both types of positive and negative IC flashes have been reproduced and their polarity depends on the up and down disposition of the positive and negative charge regions. (2. The extension range of leaders is correlative with the cloud charge distribution. The leader is possible to extend through the inverted charge region all over where it is extending, but keeps away from the isolated charge area of the same polarity. (3) The channel structures also depend on the electric potential distributions in the thundercloud. Before propagating into the central area of potential wells, the leader tends to extend along the direction with the maximum of potential gradient. Once extending away from the center of potential wells, the leader tends to extend along the direction with the slowest potential change. (4) The IC flash channels have the fractal feature with fractal dimension 1.45 before leaders pass through the central area of charge regions. The exponent decreases rapidly once leaders extend into the low-density charge regions. (5) The induced charges of opposite polarity are deposited in the leader channels within preexisting positive and negative charge regions during IC flash discharges. This causes a new and complicated charge distribution in the thundercloud, and the potential

关键词： IC, lightning parameterization, branched bilevel structure, fractal feature, propagation tendency.

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Theoretical studies on the possible conformers and properties of tetranitrodiazidoacetylhexaazaisowurtzitane (TNDAIW)

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science China Chemistry 2004年第5期47卷 414-419页

作者： WU Yukai1. OU Yuxiang1. LIU Zhiguo1.2., LIU Jinquan1. MENG Zheng1.& CHEN Boren1.1. School of Materials {1. and Engineering, {1. Institute of {2., {1. 1.0081. China 2. School of Chemistry and Chemical Engineering, Henan university, Kaifeng 475001. China 1. School of Materials science and Engineering Beijing Institute of Technology 100081 Beijing China 2. School of Chemistry and Chemical Engineering Henan University 475001 Kaifeng China

Tetranitrodiazidoacetylhexaazaisowurtzitane (TNDAIW) is a novel polyazapolycyclic caged polyazidonitramine explosive first synthesized in our laboratory. All of the possible con- formers of TNDAIW are optimized using both the AM1.and PM3 methods. TNDAIW is predicted to have more polymorphs than hexanitrohexaazoisowurtzitane (CL-2.). The HF/6-31.(d) level of theory is used to investigate the lowest energy structures of D-TNDAIW for both AM1.and PM3. The possible conformers of TNDAIW are predicted to be more stable than epsilon-CL-2. based on the N-NO2.bond lengths. The impact and shock sensitivities of both the possible DA- and DP-TNDAIW are lower than the corresponding ones of epsilon-CL-2.. TNDAIW with the possible conformers is estimated to be a promising novel high energy density explosive.

关键词： tetranitrodiazidoacetylhexaazaisowurtzitane, molecular modeling, impact and shock sensitivities.

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Monte Carlo calculation method on low energy electronscattering in polybasic medium

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Chinese science Bulletin 1998年第2期43卷 171-174页

作者： TAN Zhenyu 1.and HE Yancai 2.1. {1. of Electric Power, Shandong {1. of {2., Jinan 2.0061. China 2. Shanghai Institute of Ceramics, Chinese Academy of sciences, Shanghai 2.0050, China college of Electric Power Shandong University of Technology Jinan China Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai China

A novel Monte Carlo method of simulating low energy electron (LEE) scattering in polybasic medium is presented. The Mott cross section is adopted to describe the elastic scattering of LEE, and a mean cross section idea is proposed instead of usual determination of the scattering center. The Joy’’s modified Bethe equation is used to calculate energy loss of LEE. The scattering processes of LEE in bulk PMMA have been simulated. And the electron backscattering coefficients, the electron interaction range and energy dissipation distribution of LEE in bulk PMMA have been calculated and compared with those calculated by the method of determining scattering center.

关键词： low_energy electron scattering Monte Carlo method cross_section.

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Numerical simulation of Meiyu front and the diagnosis of moist vorticity vector

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Progress in Natural science:Materials International 2007年第11期17卷 1341-1347页

作者： Ping Fan1.2.and Luo Zhexian2.1. Institute of Atmospheric Physics, Chinese Academy of sciences, {1. 1.002., China 2. Nanjing {2. of Information sciences & technology, Nanjing 2.0044, China) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Nanjing university of Information {1.s & {2. Nanjing 210044 China

Moist vorticity vector is introduced to study the development and evolution of mesoscale convective vortex (MCV) in the Meiyu front precipitation with the Advanced Regional Predication System (ARPS). In this study, the heavy rainfall is simulated to investigate the genesis, development and dissipation of middle scale convective vortex, which occurred from 0000 UTC 3 July to 1.0}0 UTC 5 July over the Jianghuai River valley. Moist vorticity vector (MVV) has zonal, radial and vertical components in its 3D spatial distribution. The simulation shows that the vertical component of moist vorticity vector well demonstrates the spatial distribution characteristics of middle scale convective vortex, especially in the process of Meiyu front precipitation. Diagnosis upon zonal, radial averaged and mass-integrated quantities of MVV shows that its vertical component and the surface precipitating ratio are in phase with a correlation coefficient of 0.68, indicating that the vertical component of MVV is closely associated with the Meiyu front precipitation. In addition, the tendency of the vertical component of MVV is mainly determined by the interaction between the vorticity and the zonal and radial gradient of condensational or depositional heating.

关键词： moist vorticity vector mesoscale convective vortex Meiyu front precipitation

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