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Swelling of K＋, Na＋ and Ca2＋-montmorillonites and hydration of interlayer cations： a molecular dynamics simulation

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Chinese Physics B 2010年第10期19卷 652-658页

作者： Liu tao Tian Xiao-Feng Zhao Yu gao tao Institute of Atomic and Molecular Physics Sichuan University Chengdu 610065 China Institute of Mountain Hazards & Environment Chinese Academy of Sciences ~ Ministry of Water Conservancy Chengdu 610041 China

This paper performs molecular dynamics simulations to investigate the role of the monovalent cations K, Na and the divalent cation Ca on the stability and swelling of montmorillonite. The recently developed CLAYFF force field is used to predict the basal spacing as a function of the water content in the interlayer. The simulations reproduced the swelling pattern of these montmorillonites, suggesting a mechanism of their hydration different （K＋〈 Na＋〈 Ca2＋） from that of K＋-, Na＋-, and Ca2＋-montmorillonites. In particular, these results indicate that the valence of the cations has the larger impact on the behaviour of clay water systems. It also finds that the differences in size and hydration energy of K＋, Na＋ and Ca2＋ ions have strong implications for the structure of interlayer. This leads to the differences in the layer spacings of the simulated K＋-, Na＋-, and Ca2＋-montmorillonites. Furthermore, these simulations show that the K cations interact strongly with the clay sheets for the dehydrated clay sheets, but for the hydrated clays the Ca cations interact clearly strongly with the clay sheets.

关键词： montmorillonite molecular dynamics simulation swelling hydration energy

Redundant discrete wavelet transforms based moving object recognition and tracking

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Journal of Systems Engineering and Electronics 2009年第5期20卷 1115-1123页

作者： gao tao Liu Zhengguang Zhang Jun School of Electrical Engineering and Automation Tianjin Univ. Tianjin 300072 P. R. China

A method for moving object recognition and tracking in the intelligent traffic monitoring system is presented. For the shortcomings and deficiencies of the frame-subtraction method, a redundant discrete wavelet transform （RDWT） based moving object recognition algorithm is put forward, which directly detects moving objects in the redundant discrete wavelet transform domain. An improved adaptive mean-shift algorithm is used to track the moving object in the follow up frames. Experimental results show that the algorithm can effectively extract the moving object, even though the object is similar to the background, and the results are better than the traditional frame-subtraction method. The object tracking is accurate without the impact of changes in the size of the object. Therefore the algorithm has a certain practical value and prospect.

关键词： traffic monitoring moving object recognition moving object tracking redundant discrete wavelet.

Efficient identity-based signature over NTRU lattice

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Frontiers of Information Technology & Electronic Engineering 2016年第2期17卷 135-142页

作者： Jia XIE Yu-pu HU Jun-tao gao Wen gao School of Telecommunications Engineering Xidian University Xi'an 710071 China The State Key Laboratory of Integrated Services Network Xi 'an 710071 China

Identity-based signature has become an important technique for lightweight authentication as soon as it was proposed in ***,identity-based signature schemes based on the integer factorization problem and discrete logarithm problem were proposed one after ***,the rapid development of quantum computers makes them ***,many efforts have been made to construct identity-based signatures over lattice assumptions against attacks in the quantum ***,their efficiency is not very *** this study,an efficient identity-based signature scheme is presented over the number theory research unit(NTRU) lattice *** new scheme is more efficient than other lattice-and identity-based signature *** new scheme proves to be unforgeable against the adaptively chosen message attack in the random oracle model under the hardness of the γ-shortest vector problem on the NTRU lattice.

关键词： Identity Signature Lattice Number theory research unit (NTRU)

Synthesis of Novel 1-Alkyl-2-chloro(alkoxy)-1H-indole 3-Carbaldehyde Oximes and Oxime-ethers(esters) Derivatives

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Chemical Research in Chinese Universities 2009年第4期25卷 465-473页

作者： gao Wen-tao gao De-peng GUO Hui Institute of Superfine Chemicals Bohai University Jinzhou 121000 P. R. China

A convenient synthesis of 1-alkyl-2-chloro-1H-indole-3-carbaldehyde oximes（5a―5d） and 1-alkyl-2-phenoxy-1H-indole-3-carbaldehyde oximes（6a―6d） from 2-indolone was completed via the Vilsmeier-Haack reac-tion,with N-alkylation and oximation as the key *** improved one-pot method for the synthesis of 1-alkyl-2-alkoxy-1H-indole-3-carbaldehyde oximes（7a―7h） from 1-alkyl-2-chloro-1H-indole-3-carbaldehydes（3a―3d） was *** Williamson reactions and esterification reactions were performed and the oxime-ethers and oxime-esters were synthesized,*** new synthesized compounds（3a―11d） were characterized by 1H NMR,IR,MS,and elemental analysis.

关键词： Oxime Indole Vilsmeier-Haack reaction Williamson reaction One-pot method

Simulation on scrap melting behavior and carbon diffusion under natural convection

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International Journal of Minerals,Metallurgy and Materials 2021年第3期28卷 380-389页

作者： Ming gao Jin-tao gao Yan-ling Zhang Shu-feng Yang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

A 3D model applying temperature-and carbon concentration-dependent material properties was developed to describe the scrap melting behavior and carbon diffusion under natural *** results agreed reasonably well with experimental *** melting was subdivided into four stages:formation of a solidified layer,rapid melting of the solidified layer,carburization,and carburization+normal *** carburization stage could not be ignored at low temperature because the carburization time for the sample investigated was 214 s at 1573 K compared to 12 s at 1723 *** thickness of the boundary layer with significant concentration difference at 1573 K increased from 130μm at 5 s to 140μm at 60 *** maximum velocity caused by natural convection decreased from 0.029 m·s^(−1)at 5 s to 0.009 m·s^(−1)at 634 s because the differences in temperature and density between the molten metal and scrap decreased with time.

关键词： scrap melting natural convection carbon diffusion numerical simulation electron probe micro-analyzer

Application and prospective of 3D printing in rock mechanics: A review

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International Journal of Minerals,Metallurgy and Materials 2021年第1期28卷 1-17页

作者： Yong-tao gao Tian-hua Wu Yu Zhou Key Laboratory of Ministry for Efficient Mining and Safety of Metal Mines University of Science and Technology BeijingBeijing 100083China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China

This review aims to discuss the application and development of three-dimensional printing(3DP) technology in the field of rock mechanics and the mechanical behaviors of 3D-printed specimens on the basis of various available printing *** review begins with a brief description of the concepts and principles associated with 3DP, and then systematically elaborates the five major applications of 3DP technology in the field of rock mechanics, namely, the preparation of rock(including pre-flawed rock) specimens, preparation of joints, preparation of geophysical models, reconstruction of complex rock structures, and performance of bridging experimental testing and numerical ***, the mechanical performance of 3D-printed specimens created using six different printing materials, such as polymers, resin,gypsum, sand, ceramics, and rock-like geological materials, is reviewed in ***, some improvements that can make these 3D-printed specimens close to natural rocks and some limitations of 3DP technology in the application of rock mechanics are *** prospects that are required to be investigated in the future are also ***, a brief summary is *** review suggests that 3DP technology, especially when integrated with other advanced technologies, such as computed tomography scanning and 3D scanning, has great potential in rock mechanics field.

关键词： three-dimensional printing(3DP) rock mechanics 3DP material rock analogue 3DP geotechnical model numerical simulation

Study on Synthesis of Azo-Coupling Products of 3-Aminotropolone

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Chinese Chemical Letters 2001年第2期12卷 103-106页

作者： Wen tao gao Zhuo ZHENG Department of Chemistry Jinzhou Teachers CollegeJinzhou 121003 Dalian Institute of Chemical Physics Chinese Academy of ScienceDalian 116023

3-Acetamidotropolone 1 reacted with p-substitutedbenzenediazonium chloride in pyridine to afford 3-acetamido-5-(4-substitutedphenylazo)tropolones 2a~f. Hydrolysis of compounds 2a~f gave 3-amino-5-(4-substitutedphenylazo)tropolones 3a~f which could not be obtained directly from reactions of 3-aminotropolone with p-substitutedbenzenediazonium chloride. The structures of these new compounds 2a, 2c~f, 3a, 3c~f were confirmed from the elemental analysis and spectral data.

关键词： 3-Acetamidotropolone 3-aminotropolone synthesis azo-coupling electrophilic substitution

Spatial distribution of supra-permafrost groundwater in the Qinghai-Tibet Engineering Corridor using inversion models

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Advances in Climate Change Research 2024年第1期15卷 31-41页

作者： Yu gao Ming-Tang CHAI Wei MA Yu-tao gao State Key Laboratory of Frozen Soils Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 73000China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China School of Civil and Hydraulic Engineering Ningxia UniversityYinchuan 750021China

Supra-permafrost groundwater(SPG)is a key factor that causes damage to highways and railways in the Qinghai-Tibet Engineering Corridor(QTEC).It is difficult to monitor SPG in the field due to their complex formation mechanisms and movement *** single-site field monitoring studies limit the spatial and temporal precision of SPG spatial *** determine the moisture content of shallow soils and the SPG distribution along the QTEC,this work employed the temperature vegetation dryness index and remote sensing models for groundwater table distribution *** accuracies of the models were validated using mea-surements obtained from different sites in the *** the permafrost zones of the QTEC,72%,22%and 6%of the SPG were located at depths of 0.5-1,1 m,***,79.4%of the area along the Qinghai-Tibet Highway(QTH)(Xidatan-Tanggula)section contained *** these sections with SPG,37.9%have an SPG table at depths of 0.5-0.8 *** study preliminarily explored the SPG distribution in the QTEC with a 30 m *** findings can help improve the spatial scale of SPG research,provide a basis for the analysis of the hydrothermal mechanisms,and serve as a guide in the assessment of operational risks and road structure designs.

关键词： Dryness index Landsat Soil moisture Groundwater level Qinghai-Tibet Engineering Corridor

CURING PROCESS OF PHOTOPOLYMER RESIN BOND DIAMOND TOOLS

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Chinese Journal of Mechanical Engineering 2007年第3期20卷 6-8页

作者： gao tao PENG Wei YAO Chunyan Ministry of Education Key Laboratory of Mechanical ManufactureZhejiang University of Technology Hangzhou 310014 China

Analytical simulation and corresponding proof-test are adopted to study the principle of the curing process of photopolymer resin diamond tools. The influence of the diamond as abrasives in photopolymer resin owing to the absorptivity of the diamond for the UV light on the photopolymer resin curing process is discussed. Based on the above, a kind of diamond tool—dicing blade is selected to analyze the curing process of photopolymer bond diamond tools. An analytical model of curing process is developed and a correlation curve between the depth of polymerization of the photopolymer resin diamond tools and the exposure time to represent the curing process of photopolymer bond dicing blade. A test is done to proof-test the validity of the analytical model and the correlation curve. The simulated data fit the experimental results, which demonstrates the analytical models and numerical algorithm are of high reliability. The analytical simulation method could possibly be used to optimize the curing cycle and improve the quality of the photopolymers resin bond diamond tools.

关键词： Photopolymer Curing process Simulation Diamond tools