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Nonlinear effects of the finite amplitude ultrasound wave in biological tissues

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Chinese Science Bulletin 2000年第6期45卷 508-512页

作者： Xiaozhou Liu Xiufen Gong Shigong Ye Weiya Zhang Nanjing Univ Inst Acoust State Key Lab Modern Acoust Nanjing 210093 Peoples R China

Nonlinear effects will occur during the transmission of the finite amplitude wave in biological tissues. The theoretical prediction and experimental demonstration of the nonlinear effects on the propagation of the finite amplitude wave at the range of biomedical ultrasound frequency and intensity are studied. Results show that the efficiency factor and effective propagation distance will decrease while the attenuation coefficient increases due to the existence of nonlinear effects. The experimental results coincided quite well with the theory. This shows that the effective propagation distance and efficiency factor can be used to describe quantitatively the influence of nonlinear effects on the propagation of the finite amplitude sound wave in biological tissues.

关键词： nonlinear effects efficiency factor effective attenuation coefficient effective propagation distance.

Relationship between giant magnetoresistance of NiFe/Cu multilayers and their microstructures

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Chinese Science Bulletin 1998年第15期43卷 1268-1271页

作者： Hongwei Jiang Guangming Luo Zhenhong Mai Wuyan Lai Chinese Acad Sci Inst Phys State Key Lab Magnetism Beijing 100080 Peoples R China

The (111)_orientated NiFe/Cu multilayers were prepared by magnetron sputtering method. At room temperature, saturation magnetoresistances of NiFe/CU multilayers oscillate as a function of Cu spacer layer thickness. Two peak GMR values of 19 4%, 11 6% and 11 2%, 1% appear, respectively, at Cu sublayer thickness of t Cu =1 0, 2 2 nm while the deposition pressures are 0 25 and 0 45 Pa. X_ray small_angle reflections and diffuse scattering at Cu K_edge (8 979 keV) by synchrotron radiation source were used to characterize the interfacial roughness. Diffraction anomalous fine_structure scattering (DAFS) was performed to investigate the local structure of NiFe and Cu sublayers. Results show that the deposition pressure has effect on interfacial roughness of the samples obviously, and the interfacial roughness also affects the GMR values of the samples strongly.

关键词： multilayer GMR synchrotron radiation interface roughness.

Occupant evacuation model based on cellular automata in fire

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Chinese Science Bulletin 2002年第17期47卷 1484-1488页

作者： Lizhong Yang Weifeng Fang Rui Huang Zhihua Deng Univ Sci & Technol China State Key Lab Fire Sci Anhua 230026 Peoples R China

By applying the rules set in traffic flow and pedestrian flow models, a basic cellular automata model is presented to simulate occupant evacuation in fire. Some extended models are introduced to study the special phenomena of evacuation from the fire room. The key of the models is the introduction of the danger grade which makes the route choice convenient and reasonable. Fire not only influences the emotional and behavioral characteristics of an individual but also affects his physical constitution, which reduces his maximal possible velocity. The models consider these influence factors by applying a set of simple but effective rules. It is needed to emphasize that all rules are established according to the essential phenomenon in fire evacuation, that is, all the occupants would try to move to the safest place as fast as possible. Some simulation examples are also presented to validate the applicability of the models.

关键词： cellular automata pedestrian flow fire occupant evacuation model.

Crystallographic studies on the binding of coenzyme analogs to D-glyceraldehyde-3-phosphate dehydrogenase from Palinurus versicolor

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Chinese Science Bulletin 2000年第13期45卷 1199-1202页

作者： Yuequan Shen Zhaojie Wang Shiying Song Junmei Zhou Zhengjiong Lin Chinese Acad Sci Inst Biophys State Key Lab Biomacromol Beijing 100101 Peoples R China

In contrast with the coezyme, two coenzyme analogs, ADP-ribose and SNAD, bind non-cooperatively to D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Palinurus versicolor (PV) GAPDH complexed with ADP-ribose and SNAD has been crystallized by the method of sitting-drop vapor diffusion. X-ray diffraction data analysis reveals that both crystals belong to the same space group (C2), and have similar cell dimensions: a =152.80 A, b =100.35 A, c =128.31 A, β=110.28° and a =153.41 A, b =100.51 A, c =128.44 A, β =110.48°, respectively. It is estimated that the asymmetric unit in each crystal contains 4 subunits. This is a novel crystal form which is quite different from that previously reported for holo- and apo-GAPDH from the same spurce. The result suggests that the binding of the two coenzyme analogs to GAPDH may lead to some significant conformational changes, which are different from those induced by the coenzyme binding. The self-rotation function indicates that the tetramer of these two GAPDH

关键词： D-glyceraldehyde-3-phosphate dehydrogenase ADP-ribose SNAD crystal growth X-ray analysis.

Photoluminescence from Er^(3+) ion and SnO_2 nanocrystal co-doped silica thin films

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Chinese Optics Letters 2012年第9期10卷 72-75页

作者：张晓伟林涛江小帆徐骏刘建峰徐岭陈坤基 School of Electronic Science and Engineering School of PhysicsNanjing University Joint Research Centers Online of solid state Microstructure Network and Information Center

Er3＋ ions embedded in silica thin films co-doped by SnO2 nanocrystals are fabricated by sol-gel and spin coating methods. Uniformly distributed 4-am SnO2 nanocrystals are fabricated, and the nanocrystals showed tetragonal rutile crystalline structures confirmed by transmission electron microscope and X-ray diffraction measurements. A strong characteristic emission located at 1.54 〉m from the Era＋ ions is iden- tified, and the influences of Sn doping concentrations on photoluminescence properties are systematically evaluated. The emission at 1.54 #m from Era＋ ions is enhanced by more than three orders of magnitude, which can be attributed to the effective energy transfer from the defect states of SnO2 nanocrystals to nearby Er3＋ ions, as revealed by the selective excitation experiments.

关键词： SnO ion and SnO2 nanocrystal co-doped silica thin films Photoluminescence from Er

Removal of Trace Olefins from Aromatics Catalyzed by[bmim]Br-AlCl_3 Ionic Liquid

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China Petroleum Processing & Petrochemical Technology 2010年第2期12卷 41-44页

作者： Jiang Zhenghong Hou Minghui Weng Huixin Shi Li (state Key lab of Chemical Engineering,East China University of Science & Technology,Shanghai 200237) state Key lab. of Chemical Engineering East China University of Science and Technology Shanghai 200237 China

1-Butyl-3-methylimidazolium bromochloroaluminate （[bmim]Br-AlCl3） ionic liquid was used as an acid catalyst for removal of trace olefins from the aromatic hydrocarbons. The influence of various reaction parameters such as reaction time, temperature, dosage and acid strength of catalyst was investigated. The experimental results demonstrated that the ionic liquid exhibited excellent activity under mild reaction conditions, with the conversion of olefins reaching 98.84% and the bromine index of the aromatics varying from 1129 to 13. On the basis of the results obtained, thereof, a possible reaction mechanism was proposed.

关键词： ionic liquid bromine index olefins removal aromatics catalyst

Liquid Flow in Shaped Fiber Bundle

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Journal of Donghua University(English Edition) 2006年第5期23卷 87-90页

作者：张艳王华平陈跃华 College of Textiles Donghua University state Key lab for Modification of Chemical Fibers & Polymer Materials Donghua University

By computation and comparison of the critical spreading coefficient parameter, it was found that shaped fiber bundle is better for wetting. Liquid-air interface tension of liquid arising the shaped fiber bundle body is considered as one critical factor besides liquid viscosity, inertia force and liquid-fiber interface tension. Experimental result simulation demonstrated that the liquid-air interface tension is correlated with the geometric size of the liquid arising in body, Φ0 （x） and which is affected by the cross sectional shape of fiber and the radius of single fiber. The shaped fiber bundle model is/ntroduced to/nvestigate liquid flow in fiber assembly. The model is generated based on a random function for stochastic forming of fibers in bundle and it is necessary to combine this fundamental model with physical explanation for investigation of liquid flow in fiber assembly.

关键词： shaped fiber liquid model.

Gregory solid Construction for Polyhedral Volume Parameterization by Sparse Optimization

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Applied Mathematics(A Journal of Chinese Universities) 2019年第3期34卷 340-355页

作者： HU Chuan-feng LIN Hong-wei School of Mathematics Zhejiang UniversityHangzhou 310027China state Key lab of CAD&CG Zhejiang UniversityHangzhou 310027China

In isogeometric analysis,it is frequently required to handle the geometric models enclosed by four-sided or non-four-sided boundary patches,such as trimmed *** this paper,we develop a Gregory solid based method to parameterize those ***,we extend the Gregory patch representation to the trivariate Gregory solid ***,the trivariate Gregory solid representation is employed to interpolate the boundary patches of a geometric model,thus generating the polyhedral volume *** improve the regularity of the polyhedral volume parametrization,we formulate the construction of the trivariate Gregory solid as a sparse optimization problem,where the optimization objective function is a linear combination of some terms,including a sparse term aiming to reduce the negative Jacobian area of the Gregory ***,the alternating direction method of multipliers(ADMM)is used to solve the sparse optimization *** of experimental examples illustrated in this paper demonstrate the effectiveness and efficiency of the developed method.

关键词： Gregory solid Polyhedral volume parametrization Sparse optimization Regularity Isogeometric analysis

Reduced precision solution criteria for nonlinear model predictive control with the feasibility-perturbed sequential quadratic programming algorithm

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第11期12卷 919-931页

作者： Jiao-na WAN Zhi-jiang SHAO Ke-xin WAN Xue-yi FANG Zhi-qiang WANG Ji-xin QIAN state Key lab of Industrial Control Technology Institute of Industrial Control Department of Control Science and Engineering Zhejiang University Hangzhou 310027 China

We propose a novel kind of termination criteria, reduced precision solution (RPS) criteria, for solving optimal control problems (OCPs) in nonlinear model predictive control (NMPC), which should be solved quickly for new inputs to be applied in time. Computational delay, which may destroy the closed-loop stability, usually arises while non-convex and nonlinear OCPs are solved with differential equations as the constraints. Traditional termination criteria of optimization algorithms usually involve slow convergence in the solution procedure and waste computing resources. Considering the practical demand of solution precision, RPS criteria are developed to obtain good approximate solutions with less computational cost. These include some indices to judge the degree of convergence during the optimization procedure and can stop iterating in a timely way when there is no apparent improvement of the solution. To guarantee the feasibility of iterate for the solution procedure to be terminated early, the feasibility- perturbed sequential quadratic programming (FP-SQP) algorithm is used. Simulations on the reference tracking performance of a continuously stirred tank reactor (CSTR) show that the RPS criteria efficiently reduce computation time and the adverse effect of computational delay on closed-loop stability.

关键词： Nonlinear model predictive control (NMPC) Computational delay Termination criteria Continuously stirred tankreactor (CSTR)