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Frontiers of Mechanical Engineering 2016年第2期11卷 135-143页

作者： Fugui xie Xin-Jun LIU The State Key Laboratory of Tribology & Institute of Manufacturing Engineering Department of Mechanical Engineering Tsinghua Uni- versity Beijing 100084 China Beijing Key Laboratory of precision/ Ultra-precision Manufacturing Equipment and Control Tsinghua University Beijing 100084 China

This study introduces a high-speed parallel robot with Schonflies motion. This robot exhibits a promising prospect in realizing high-speed pick-and- place manipulation for packaging production lines. The robot has four identical limbs and a single platform. Its compact structure and single-platform concept provides this robot with good dynamic response potential. A line graph method based on Grassmann line geometry is used to investigate the mobility characteristics of the proposed robot. A generalized Blanding rule is also introduced into this procedure to realize mutual conversion between the line graphs for motions and constraints. Subsequently, the inverse kinematics is derived, and the singularity issue of the robot is investigated using both qualitative and quantitative approaches. Input and output transmission singularity indices are defined based on the reciprocal product in screw theory and the virtual coefficient by considering motion/force transmission performance. Thereafter, the singular loci of the proposed robot with specific geometric parameters are derived. The mobility analysis, inverse kinematics modeling, and singularity analysis conducted in this study are helpful in developing the robot.

关键词： parallel robot mobility inverse kinematics,singularity transmission performance

Fractional Smoothness of Some Stochastic Integrals

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Acta Mathematica Sinica,English Series 2007年第6期23卷 1053-1058页

作者： peng xie Xi Cheng zHANG Department of Mathematics Huazhong University of Science and Technology Wuhan 430074 P. R. China

We study the fractional smoothness in the sense of Malliavin calculus of stochastic integrals of the form ∫0^1Ф（Xs）dXs, where Xs is a semimartingale and Ф belongs to some fractional Sobolev space over R.

关键词： fractional Sobolev space stochastic integral interpolation

Fluorescence Turn-On/Off Responses of In(Ⅲ)-MOF to Short-Chain perfluorocarboxylic Acids

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Transactions of Tianjin University 2023年第3期29卷 216-224页

作者： Jie Lv Yabo xie Lin-Hua xie Jian-Rong Li Beijing Key Laboratory for Green Catalysis and Separation Department of Chemical EngineeringBeijing University of TechnologyBeijing 100124China

Short-chain perfluorocarboxylic acids(pFCAs) are a class of persistent organic pollutants that are widely used as substitutes for long-chain pFCAs. However, they also pose a non-negligible risk to ecosystems. In this study, we demonstrated that a fluorescent metal–organic framework(MOF)(named V-101) constructed from In^(3+)and an aromatic-rich tetratopic carboxylate ligand 5-[2,6-bis(4-carboxyphenyl) pyridin-4-yl] isophthalic acid(H4BCpIA) exhibited highly efficient turn-off and turn-on fluorescence responses toward five short-chain pFCAs in water and methanol, respectively. The limits of detection of V-101 toward five short-chain pFCAs are down to μg/L level, and it showed good anti-interference abilities toward short-chain pFCAs in the presence of common metal ions. The major mechanisms associated with fluorescence responses were molecular collisions and interactions between V-101 and short-chain pFCAs. This work demonstrates that the structure variety of MOFs imparts them with the potential of MOFs in the detection of short-chain pFCAs for pollution control.

关键词： perfl uorocarboxylic acids Fluorescent detection Metal–organic framework(MOF)

Thermal Stability and Transformation-mediated Deformability of Cu-zr-Al-Ni Bulk Metallic Glass Composite

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Journal of Materials Science & Technology 2013年第9期29卷 868-872页

作者： Meiting xie pengna zhang Kaikai Song School of Mechanical Engineering Binzhou Polytechnic College of Math and physics Nanjing University of Information Science and Technology IFW Dresden Institut für Komplexe Materialien TU Dresden Institut für Werkstoffwissenschaft

The glass-forming ability and the thermal stability of Cu45zr45AI5Ni5 metallic glass were systematically investigated by the differential scanning calorimetry. The activation energies for the glass transition and the onset crystallization and the crystallization peak were calculated to be 255.1, 308.7 and 311.5 kJ/mol, respectively, while the corresponding liquid fragility was determined to be 23.4. By controlling the casting process, Cu45zr45AI5Ni5 bulk metallic glass composite with the presence of ductile B2 Cuzr phase was fabricated. The composite shows a pronounced plastic strain of 6.8 ~ 0.05% with obvious work hardening, which results from the formation of multiple shear bands and the deformation-induced martensitic transformation.

关键词： Amorphous Activation energy Martensitic transformation Mechanical properties

Influence of the Compacts Homogeneity on the Incidence of Cracks during Thermal Debinding in Ceramic Injection Molding

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Journal of Materials Science & Technology 2009年第2期25卷 264-268页

作者： Xianfeng Yang zhipeng xie Yong Huang State Key Laboratory of New Ceramics and Fine processing Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

During thermal debinding in ceramic injection molding, the inhomogeneity of green body is a key origin of cracks. In this study, the impact of low molecular weight binders on the homogeneity of the green body was investigated. Incidence of cracks during thermal debinding indicated that the volume ratio of wax to stearic acid should be out of high viscosity and incompletely wetting region. In these two formulation regions, typical inhomogeneous microstructures were observed. By mercury intrusion method, it was shown that pore size distribution of the debinded compacts was determined by thermal degradation of low molecular weight binders. A particle-rich region model was established to predict the nucleation of cracks caused by solid loading fluctuation. The criterion of cracks nucleation was that local capillary force from solid loading fluctuation was larger than the suction force from the surroundings.

关键词： Ceramic injection molding Cracks Debinding Homogeneity

Effects on the phase Transformation Temperature of Nanofluids by the Nanoparticles

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Journal of Materials Science & Technology 2008年第5期24卷 742-744页

作者： Huaqing xie Jifen WAN Lifei CHEN Department of Environmental Engineering Shanghai Second Polytechnic University Shanghai 201209 China

Nanofluids have been demonstrated to have intriguing thermodynamic properties. In this work, we described the investigation of the phase transformation behaviors of nanofluids containing alumina （Al2O3） or titania （TiO2） nanoparticles with different weight fractions. The experimental results indicate that the melting temperatures of nanofluids （in freezing states） are reduced with the increase of the weight fraction of nanoparticles. The reduction is related to nanoparticle species as well as nanoparticle size.

关键词： Nanofluids Thermal analysis Melting

Observations of semidiurnal M 2 internal tidal parametric subharmonic instability in the northeastern South China Sea

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Journal of Oceanology and Limnology 2021年第1期39卷 56-63页

作者： Qian LIU Xiaodong SHANG Xiaohui xie School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Southern Marine Science and Engineering Guangdong Laboratory Guangzhou 511458China State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310000China

Near-diurnal vertically-standing waves with high vertical wavenumbers k z were observed in the velocity and shear fi elds from a set of 75-d long ADCp moored in the northeastern South China Sea(SCS)away from the“critical”latitude of 28.8°.These enhanced near-diurnal internal waves followed a fortnightly spring-neap ***,they always happened during semidiurnal spring tides rather than diurnal springs although strong diurnal internal tides with the fortnightly spring-neap cycle were prevailing,suggesting that they were generated via subharmonic instability(pSI)of dominant semidiurnal M 2 internal *** two semidiurnal internal tidal waves with opposite vertical propagation direction intersected,both semidiurnal subharmonic and super harmonic waves were largely intensifi *** observed maximum diurnal velocity amplitudes were up to 0.25 m/*** kinetic energy and shear spectra further suggested that frequencies of daughter waves were not always perfectly equal to M 2/*** superposition of two daughter waves with nearly equal frequencies and nearly opposite k z in a pSI-triad leaded to the vertically-standing waves.

关键词： internal tides South China Sea(SCS) resonant interactions rotary spectra parametric subharmonic instability

Multibeam Raman amplification of a finite-duration seed in a short distance

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Chinese physics B 2021年第10期30卷 428-435页

作者： Y G Chen Y Chen S X xie N peng J Q Yu C z Xiao Key Laboratory for Micro-/Nano-Optoelectronic Devices of Ministry of Education School of Physics and ElectronicsHunan UniversityChangsha 410082China Collaborative Innovation Center of IFSA(CICIFSA) Shanghai Jiao Tong UniversityShanghai 200240China

A new scheme of multibeam Raman amplification(MRA)is proposed in virtue of the collective mode by sharing a common scattered *** laser beams can provide a higher growth rate,but the overlapping region limits the amplification *** suggest to use a finite-duration seed to facilitate MRA in a short *** two-dimensional particle-in-cell simulations,we find that two-beam Raman amplification has a much higher growth rate than that of singlebeam *** growth rate depends on the initial seed amplitude,electron temperature,and seed *** empirical criterion,γ0τc=1,whereγ0 is the theoretical growth rate of MRA,is used to choose a proper duration for a higher growth *** a total amplification length of 320µm,the two-beam Raman amplification shows nonlinear features of pulse compression and a bow-shape wave front,indicating that the amplification has finally entered the self-similar regime.

关键词： multibeam Raman amplification growth rate finite-duration

Graph convolutional network combined with random walks and graph attention network for node classification

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The Journal of China Universities of posts and Telecommunications 2024年第3期31卷 1-14页

作者： Chen Yong xie Xiaozhu Weng Wei College of Computer and Information Engineering Xiamen University of TechnologyXiamen 361024China Fujian Key Laboratory of pattern Recognition and Image Understanding Xiamen University of TechnologyXiamen 361024China

Graph conjoint attention(CAT)network is one of the best graph convolutional networks(GCNs)frameworks,which uses a weighting mechanism to identify important neighbor ***,this weighting mechanism is learned based on static information,which means it is susceptible to noisy nodes and edges,resulting in significant *** this paper,a method is proposed to obtain context dynamically based on random walk,which allows the context-based weighting mechanism to better avoid noise ***,the proposed context-based weighting mechanism is combined with the node content-based weighting mechanism of the graph attention(GAT)network to form a model based on a mixed weighting *** model is named as the context-based and content-based graph convolutional network(CCGCN).CCGCN can better discover important neighbors,eliminate noise edges,and learn node embedding by message *** show that CCGCN achieves state-of-the-art performance on node classification tasks in multiple datasets.

关键词： graph neural network(GNN) graph convolutional network(GCN) semi-supervised classification graph analysis

Morphological evolution of a large sand bar in the Qiantang River Estuary of China since the 1960s

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Acta Oceanologica Sinica 2022年第2期41卷 156-165页

作者： Junbao Huang zhilin Sun Dongfeng xie Ocean College Zhejiang UniversityZhoushan 316021China zhejiang Institute of Hydraulics and Estuary Hangzhou 310020China College of Civil Engineering and Architecture Zhejiang UniversityHangzhou 310058China

A large sand bar develops in the inner Qiantang River Estuary,*** is a unique sedimentary system,elongating landwards by about 130 *** on long-term series of bathymetric data in each April,July,and November since the 1960s,this study investigated the morphological behavior of this bar under natural conditions and the influence of a large-scale river narrowing project(LRNp)implemented in the last *** results show that three timescales,namely the seasonal,interannual and decadal timescales,can be distinguished for the sand bar *** first two are related to the seasonal and interannual variations of river *** high discharge seasons or years,erosion took place at the upper reach and sedimentation at the lower ***,the bar apex shifted *** opposite development took place during low discharge seasons or *** decadal timescale is related to *** to the implementation of LRNp,the upper reach has experienced apparent erosion and currently a new equilibrium state has been reached;whereas the lower reach has been accumulated seriously and the accumulation still *** relationships for how the bar apex location and elevation depend on the river discharge over various stages of LRNp have been *** with the earlier stage of LRNp,the bar apex at present has shifted seaward by about 12 km and lowered by about 1 *** sand bar movement has significant feedback on the hydrographic conditions along the estuary and has practical implications for coastal management.

关键词： morphological evolution river discharge sand bar Qiantang River Estuary river narrowing project coastal management