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Velocity field of wave-induced local fluid flow in double-porosity media

Science China(Physics,Mechanics & Astronomy) 2014年第6期57卷 1020-1030页

作者： ba Jing ZHANG Lin SUN WeiTao HAO ZhaoBing Geophysical Department Research Institute of Petroleum Exploration and Development School of Geosciences China University of Petroleum (Eastern China) Zhou Pei-Yuan Center for Applied Mathematics Tsinghua University Key Laboratory of Integrative Researches on Geophysics for Petroleum Institute of Geology and GeophysicsChinese Academy of Sciences

Under the excitation of elastic waves,local fluid flow in a complex porous medium is a major cause for wave dispersion and *** the local fluid flow process is simulated with wave propagation equations in the double-porosity medium,two porous skeletons are usually assumed,namely,host and *** them,the volume ratio of inclusion skeletons is *** previous studies have ignored the consideration of local fluid flow velocity field in inclusions,and therefore they can not completely describe the physical process of local flow oscillation and should not be applied to the situation where the fluid kinetic energy in inclusions cannot be *** this paper,we analyze the local fluid flow velocity fields inside and outside the inclusion,rewrite the kinetic energy function and dissipation function based on the double-porosity medium model containing spherical inclusions,and derive the reformulated Biot-Rayleigh(BR)equations of elastic wave propagation based on Hamilton’s *** present simulation examples with different rock and fluid *** between BR equations and reformulated BR equations show that there are significant differences in wave response ***,we compare the reformulated BR equations with the previous theories and experimental data,and the results show that the theoretical results of this paper are correct and effective.

关键词： double-porosity medium elastic wave propagation local fluid flow velocity dispersion Biot-Rayleigh equations petro-physical experiment

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Optimization of antioxidant activity by response surface methodology in hydrolysates of jellyfish(Rhopilema esculentum) umbrella collagen

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2009年第8期10卷 572-579页

作者： Yong-liang ZHUANG Xue ZHAO ba-fang LI College of Food Science and Engineering Ocean University of China Qingdao 266003 China

To optimize the hydrolysis conditions to prepare hydrolysates of jellyfish umbrella collagen with the highest hydroxyl radical scavenging activity, collagen extracted from jellyfish umbrella was hydrolyzed with trypsin, and response surface methodology （RSM） was applied. The optimum conditions obtained from experiments were pH 7.75, temperature （T） 48.77 ℃, and enzyme-to-substrate ratio （[E]/[S]） 3.50%. The analysis of variance in RSM showed that pH and [E]/[S] were important factors that significantly affected the process （P〈0.05 and P〈0.01, respectively）. The hydrolysates of jellyfish umbrella collagen were fractionated by high performance liquid chromatography （HPLC）, and three fractions （HF-1〉3000 Da, 1000 Da〈HF-2〈3000 Da, and HF-3〈1000 Da） were collected. The HF-2 fraction had the highest hydroxyl radical scavenging activity with the highest yield compared with the other two fractions. Furthermore, HF-2 also showed the strongest Cu^2＋-chelating ability and the best tyrosinase-inhibitory activity.

关键词： Jellyfish umbrella collagen Hydrolysis Antioxidant activity Response surface methodology (RSM)

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Nonlinear Mathematical Modeling and Sensitivity Analysis of Hydraulic Drive Unit

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Chinese Journal of Mechanical Engineering 2015年第5期28卷 999-1011页

作者： KONG Xiangdong YU Bin QUAN Lingxiao ba Kaixian WU Liujie National Engineering Research Center for Local Joint of Advanced Manufacturing Technology and Equipment Yanshan University Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University School of Mechanical Engineering Yanshan University

The previous sensitivity analysis researches are not accurate enough and also have the limited reference value, because those mathematical models are relatively simple and the change of the load and the initial displacement changes of the piston are ignored, even experiment verification is not conducted. Therefore, in view of deficiencies above, a nonlinear mathematical model is established in this paper, including dynamic characteristics of servo valve, nonlinear characteristics of pressure-flow, initial displacement of servo cylinder piston and friction nonlinearity. The transfer function block diagram is built for the hydraulic drive unit closed loop position control, as well as the state equations. Through deriving the time-varying coefficient items matrix and time-varying free items matrix of sensitivity equations respectively, the expression of sensitivity equations based on the nonlinear mathematical model are obtained. According to structure parameters of hydraulic drive unit, working parameters, fluid transmission characteristics and measured friction-velocity curves, the simulation analysis of hydraulic drive unit is completed on the MATLAB/Simulink simulation platform with the displacement step 2 mm, 5 mm and 10 mm, respectively. The simulation results indicate that the developed nonlinear mathematical model is sufficient by comparing the characteristic curves of experimental step response and simulation step response under different constant load. Then, the sensitivity function time-history curves of seventeen parameters are obtained, basing on each state vector time-history curve of step response characteristic. The maximum value of displacement variation percentage and the sum of displacement variation absolute values in the sampling time are both taken as sensitivity indexes. The sensitivity indexes values above are calculated and shown visually in histograms under different working conditions, and change rules are analyzed. Then the sensitivity index

关键词： nonlinear mathematical model hydraulic drive unit valve-controlled symmetrical cylinder sensitivity analysis sensitivity index

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International Szent-Gyorgyi Prize for Progress in Cancer Research:basic and translational research recognition Mary-Claire King received the 2016 Prize for her pioneering research that demonstrated the first evidence of genetic predisposition to breast cancer

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Chinese Journal of Cancer 2017年第11期36卷 533-536页

作者： Hali Hartmann Jie Zhao Sujuan ba National Foundation for Cancer Research

The Szent-Gy?rgyi Prize for Progress in Cancer Research is a prestigious scientific award sponsored by the National Foundation for Cancer Research(NFCR)-a leading cancer research charitable organization in the United States that supports innovative cancer research globally with the ultimate goal to cure cancer. The coveted Szent-Gy?rgyi Prize annually honors a scientist whose seminal discovery or body of work has resulted in, or led toward, notable contributions to cancer prevention, diagnosis, or treatment; and the discovery has had a high direct impact of saving people's lives. In addition, the prize promotes public awareness of the importance of basic cancer research and encourages the sustained investment needed to accelerate the translation of these research discoveries into new cancer treatments. In 2016, NFCR's Szent-Gy?rgyi Prize Selection Committee was unanimous in its decision to recognize an icon in human disease genetics, Dr. Mary-Claire King, for her pioneering research that demonstrated the first evidence of genetic predisposition to breast cancer. Her proof of existence of BRCA1 gene and its location has made genetic screening for breast and ovarian cancers possible, saving lives of many people who are at high risk with inherited BRCA1 mutations.

关键词： The National Foundation for Cancer Research The Szent-Gyorgyi Prize Mary-Claire King BRCA1 and genetic testing

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Cracking Tendency of Restrained Concrete at Early Ages

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Journal of Wuhan University of Technology(Materials Science) 2008年第2期23卷 263-267页

作者： ba Hengjing SU Anshuang GAO Xiaojian TAO Qi School of Civil Engineering Harbin Institute of Technology Harbin 150006 China

A modified testing system characterized by full automation, steady operation and high accuracy of strain and stress measurements was developed to determine the cracking tendency of high strength concrete （HSC） in restrained condition at early ages. The shrinkage stress and the tensile creep behavior of HSC at early ages were investigated. The influence of W/C ratio and curing conditions on the early-age shrinkage stress and tensile creep was evaluated. It was found that the lower W/C ratio and drying curing condition resulted in higher shrinkage stress, stress induced tensile creep and greater cracking tendency.

关键词： cracking tendency shrinkage stress tensile creep concrete early ages

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RO-heparin Inhibits L-Selectin-mediated Neutrophils Adhesion to Vascular Endothelium Under Flow Conditions

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Chemical Research in Chinese Universities 2006年第3期22卷 302-307页

作者： CHEN Zhi-hong XU Li ba Xue-qing ZENG Xian-lu Institute of Genetics and Cytology Northeast Normal University Changchun 130024 P. R. China School of Life Science Mudanjiang Medical University Mudanjiang 157011 P. R. China Biology Section College of Changchun Traditional Chinese Medicine Changchun 130017 P. R. China

Selectins are carbohydrate-binding cell adhesion molecules that play a major role in the initiation of inflammatory responses. Accumulaed evidence has suggested that heparin＇s anti-inflammatory effects are mainly mediated by blocking L-or P-selectin-initiated cell adhesion. Recently, we have reported that periodate-oxidized, borohydridereduced heparin （RO-heparln） can inhibit P-selectin-mediated acute inflammation. Here we further examined the effect of RO-heparin on the adhesion of L-selectin-mediated leukocytes to vascular endothelium under flow conditions in vivo and in vitro. The results show that RO-heparin with a low anticoagulant activity can effectively reduce leucocyte roiling on thioglycoUate-induced rat mesenterlc venules and L-selectin-metadiated neutrophil roiling on TNF-α-induced human umbilical vein endothelial cells（HUVECs） under flow conditions. Our findings suggest that the effect of RO-heparin on inflammatory responses is mainly a result of its inhibiting the interaction between P- or L-selectin and its ligands. The findings also suggest that RO-heparin may be useful in preventing inflammation diseases.

关键词： RO-heparin Neutrophils adhesion L-selectin Human umbilical vein endothelial cells (HUVECs)

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A simulation-based software to support the real-time operational parameters selection of tunnel boring machines

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Underground Space 2024年第1期14卷 176-196页

作者： Yaman Zendaki ba Trung Cao Abdullah Alsahly Steffen Freitag Gunther Meschke Institute for Structural Mechanics Ruhr University BochumBochum 44801Germany Institute for Structural Analysis Karlsruhe Institute of TechnologyKarlsruhe 76131Germany

With the fact that the main operational parameters of the construction process in mechanized tunneling are currently selected based on monitoring data and engineering experience without exploiting the advantages of computer methods,the focus of this work is to develop a simulation-based real-time assistant system to support the selection of operational *** choice of an appropriate set of these parameters(i.e.,the face support pressure,the grouting pressure,and the advance speed)during the operation of tunnel boring machines(TBM)is determined by evaluating different tunneling-induced soil-structure interactions such as the surface settlement,the associated risks on existing structures and the tunnel lining *** evaluate soil-structure behavior,an advanced process-oriented numerical simulation model based on the finite cell method is *** enable the real-time prediction capability of the simulation model for a practical application during the advancement of TBMs,surrogate models based on the Proper Orthogonal Decomposition and Radial basis Functions(POD-RBF)are *** proposed approach is demonstrated through several synthetic numerical examples inspired by the data of real tunnel *** developed methods are integrated into a user-friendly application called SMART to serve as a support platform for tunnel engineers at construction *** to each user adjustment of the input parameters,i.e.,each TBM driving scenario,approximately two million outputs of soil-structure interactions are quickly predicted and visualized in seconds,which can provide the site engineers with a rough estimation of the impacts of the chosen scenario on structural responses of the tunnel and above ground structures.

关键词： Numerical simulation Surrogate model Real-time prediction Proper orthogonal decomposition Radial basis functions TBM operation Smart construction

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Synergistically enhancing cycleability and rate performance of sodium titanate nanowire anode via hydrogenation and carbon coating for advanced sodium ion batteries

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Rare Metals 2022年第12期41卷 4075-4085页

作者： De-Liang ba Wei-Hua Zhu Yuan-Yuan Li Jin-Ping Liu School of Optical and Electronic Information Huazhong University of Science and TechnologyWuhan 430074China School of Chemistry Chemical Engineering and Life ScienceState Key Laboratory of Advanced Technology for Materials Synthesis and ProcessingWuhan University of TechnologyWuhan 430070China State Center for International Cooperation on Designer Low-Carbon and Environmental Materials and School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China

Layered alkali-metal titanate materials are considered as attractive anodes for sodium ion batteries due to their favorable safety and low ***,their practical implementation faces major challenges of low electronic conductivity and inevitable volume variation during Na^(+)intercalation and de-intercalation,which are generally difficult to conquer by a single modification ***,a synergistic ally enhancing strategy to promote the electrochemical performance of Na_(2)Ti_(2)O_(5)nanowire array anode via simultaneous hydrogenation and carbon coating is *** leads to partially reduced titanium;together with conductive carbon layer,it endows Na_(2)Ti_(2)O_(5)with fast electron transport and structural *** resulting H-Na_(2)Ti_(2)O_(5)@C anode exhibits enhanced rate capability(8.0C,165 mAh·g^(-1))and stable cycle performance up to 1000 times in sodium-ion half-cells(the capacity of H-Na_(2)Ti_(2)O_(5)without carbon fades drastically after only 100 cycles).In addition,a newcoupling full cell is further designed with graphene hybridized high-voltage Na_(3)(VO_(0.5))_(2)(PO4)_(2)F_(2)as cathode,capable of delivering a high specific energy density of 212.1 Wh·kg^(-1)(based on the mass of both anode and cathode)and good rate and cycling *** work may offer inspiration for synergistic optimization of electrode materials for advanced electrochemical energy storage devices.

关键词： Sodium ion batteries(SIBs) Na2Ti2O5 nanowire Hydrogenation Carbon coating Enhanced performance

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Effect of glass removal on the GMI effect of Co_(71.8)Fe_(4.9)Nb_(0.8)Si_(7.5)B_(15) amorphous glass-covered wires

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Rare Metals 2006年第z1期25卷 633-636页

作者： CHEN Zheng ba Shan LI Deren LU Zhichao ZHOU Shaoxiong Central Iron & Steel Research Institute Nanomaterials Engineering and Research Center Beijing 100081 China Research and Development Center Advanced Technology & Materials Co. Ltd. Beijing 100081 China Beijing Institute of Technology School of Science Beijing 100081 China Central Iron & Steel Research Institute Nanomaterials Engineering and Research Center Beijing 100081 China Research and Development Center Advanced Technology & Materials Co. Ltd. Beijing 100081 China Central Iron & Steel Research Institute Nanomaterials Engineering and Research Center Beijing 100081 China Research and Development Center Advanced Technology & Materials Co. Ltd. Beijing 100081 China

During the past several years, giant magneto-impedance effect (GMI) in amorphous wires has generated growing interest in the science community because of their applications in sensors. The giant magneto-impedance effect in Co71.8Fe4.9Nb0.8Si7.5B15 amorphous glass-covered wires (AGCW) consists of strong changes in the high frequency impedance with a small DC magnetic field. When f=1 MHz, there is no GMI effect due to the fact that the magnetic penetration depth is higher than their radius. As the frequency increases, the GMI effect becomes important in both the glass-covered wire and the wire after glass removal. Field dependence of the impedance has a similar behaviour to the AGCW ones, when a tensile stress is applied to the wire without glass cover.

关键词： giant magneto-impedance amorphous wires frequency

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Relationship between microstructure and corrosion behavior of high-grade pipeline steel in a low-temperature environment

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Journal of Iron and Steel Research International 2021年第8期28卷 1037-1046页

作者： Jia-qiang Jing Jie Guo ba Li Shu-jun Jia Yi Ren School of Oil and Gas Engineering Southwest Petroleum UniversityChengdu 610500SichuanChina Department of Structural Steels Central Iron and Steel Research InstituteBeijing 100081China State Key Laboratory of Metal Material for Marine Equipment and Application of Iron and Steel Research Institutes of Ansteel Group Corporation Anshan 114009LiaoningChina

The relationship between micro structure and corrosion behavior of high-grade pipeline steel under low-temperature conditions was comparatively investigated by the potentiodynamic polarization and electrochemical impedance spec-troscopy test combining with optical micrographs,scanning electron microscopy,transmission electron microscopy and electron back-scattered *** results showed that,compared with room and high temperature,low temperature could influence the corrosion behavior of high-grade pipeline steel,which means that the corrosion potential and current density decreased and the corrosion resistance increased ***,double layer structures of the interface became thicker and more *** low-temperature environment,acicular ferrite had the martensite/austenite constituents with less amount and smaller size,a higher density of low angle grain boundaries and smaller effective grain sizes compared with granular bainite,which demonstrated higher corrosion resistance.

关键词： Low temperature High-grade pipeline steel Corrosion behavior Resistance Acicular ferrite Granular bainite Martensite/austenite constituent

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