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The influence of mechanical loading on osseointegration:an animal study

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Science china(Life Sciences) 2009年第6期52卷 579-586页

作者： FAN YuBo1,XIU KaiHua1,DONG Xiang2 & ZHANG Ming2 1 School of Biological Science and Medical Engineering,Beihang university,Beijing 100083,china 2 department of Health Technology and Informatics,The hong kong polytechnic university,hong kong,china School of Biological Science and Medical Engineering Beihang University Beijing China department of Health Technology and Informatics The Hong Kong Polytechnic University Hong Kong China

Osseointegration of implant provides a stable support for the prosthesis under functional *** timing of loading is a critical parameter that can govern the success of the osseointegration of ***,it is not clear whether the early loading can affect the success of osseointegration,or whether the no-loading healing period can be *** paper presents an animal study conducted to investigate how external loads influence the osseointegration at the initial stage of *** implants were inserted into the goat tibia laterally,and different axial loadings were applied to the im-plants in 4 weeks after *** the 2 weeks period of early loading,animals were sacrificed and the tibia bones with the implants were cut off from the *** mechanical test was employed to find out the differences in the pull-out force,and shear strength at the bone-implant interface between the non-loaded and the loaded *** implant-bone interfaces were analyzed by histomor-phometric method,SEM(scanning electron micrograph) and EDS(energy density spectrum).The re-sults indicated that the bone-implant interface did not well integrate 4 weeks after surgery,and the fi-brous tissue could be found at the interfaces of the specimens without *** the results of loaded specimens with 10 N axial force showed that that parts of the interface were well integrated,indicating that the early mild loading may play a positive role in the process of the *** results support that a certain range of external loading would influence the process of osseointe-gration,and appropriate mechanical loading can be applied to shorten the osseointegration period after surgery.

关键词： Osseointegration implant animal model histology pull-out test

EXPERIMENTAL STUDY ON INSTANTANEOUS DISCHARGE OF UNSORTED PARTICLE CLOUD IN CROSS-FLOW

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Journal of Hydrodynamics 2008年第1期20卷 10-16页

作者： GU Jie HUANG Jing LIC. W. College of Marine Science and Technology Shanghai Fisheries University Shanghai 200090 China department of Civil and Structural Engineering The Hong Kong Polytechnic University Hong Kong China

A series of extensive laboratory experiments were conducted to investigate the transport and mixing of instantaneous discharge of unsorted particle cloud in cross-flow. The following experimental results were obtained：（1） the vertical frontal position and the longitudinal width of the particle cloud in the cross-flow is much larger than those in stagnant water, （2） the smaller cross-flow velocity will normally cause the larger non-dimensional frontal position for the same particle size range and initial volume, （3） the non-dimensional longitudinal width of the particle cloud in the cross-flow increases with the increase of cross-flow velocity. The empirical constants （α1, α3 and α2） and their variance range, which can be used to determine the relationships of non-dimensional vertical frontal position and time, longitudinal width and time, and vertical frontal position and longitudinal width were also obtained through the analysis of experimental data.

关键词： instantaneous discharge particle cloud cross-flow buoyancy hydrodynamic behavior

Spatial pattern of land cover change in china's semiarid environment

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Journal of Arid Land 2009年第1期1卷 16-25页

作者： BaoLin LI1 and QiMing ZHOU2 1 State Key Laboratory of Environment and Resources Information System, Institute of Geographical Sciences and Resources Research, Chinese Academy of Sciences, Beijing 100101, china 2 department of Geography, hong kong Baptist university, Kowloon Tong, hong kong, china State Key Laboratory of Environment and Resources Information System Institute of Geographical Sciences and Resources Research Chinese Academy of Sciences Beijing 100101 China department of Geography Hong Kong Baptist University Kowloon Tong Hong Kong

This study seeks a routine to quantify spatial pattern of land cover changes in semiarid environment of china based on post-classification comparison method. The method consists of three major steps: (1) the image classification and unification of classified results based on two-level land cover classification themes, (2) the establishment of land cover change classes based on an unification land cover classification theme, (3) the reclassification and mapping of land cover change classes with three overall classes including no-change, gain and loss based on the unification land cover class. This method was applied to detect the spatial pattern of land cover changes in Yinchuan Plain, one of famous irrigation agricultural zones of the Yellow River, china. The results showed the land cover had undergone a remarkable change from 1991 to 2002 in the study area (the changed area was over 30%). Rapid increase of cropland (12.5%), built-up area (131.4%) and rapid decrease of bare ground (51.7%) were alarming. The spatial pattern of land cover changes showed clear regional difference in the study area and was clearly related to human activities or natural factors. Thus, it obtained a better understanding of the human impact on the fragile ecosystem of china’s semiarid environment.

关键词： change detection spatial pattern land cover semiarid zone of china remote sensing human activities

Transient state model of actin-based motility

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Theoretical & applied Mechanics Letters 2011年第1期1卷 73-76页

作者： Li-miao Bai and Yuan Lin~(a)) department of Mechanical Engineering,The university of hong kong,hong kong SAR,china department of Mechanical Engineering The University of Hong Kong Hong Kong SAR China

We developed a transient model for actin-based *** of actin monomers was included in the formulation and its influence on the speed of actin-driven cargos was examined in *** results clearly demonstrated how actin polymerization accelerates cargos that are initially stationary,as well as how steady-state is eventually *** also found that,due to polymerization and diffusion,actin monomer concentration near the load surface can be significantly lower than that in the rest of the comet tail,suggesting that many previous models may not be very accurate.

关键词： actin-based motility polymerization diffusion transient state

Computer simulation on reliability of retention index with FDG-PET and optimization of dual-time-point imaging protocol

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Progress in Natural Science:Materials International 2008年第8期18卷 931-937页

作者： Rui Jia a, Jing Bai a,*, Lingfeng Wenb,c, Dagan Fengb,c a department of Biomedical Engineering, Tsinghua university, Room B209, Building of Medical Science, Beijing 100084, china b School of Information Technologies, university of Sydney, NSW 2006, Australia c department of Electronic and Information Engineering, hong kong polytechnic university, hong kong department of Biomedical Engineering Tsinghua University Room B209 Building of Medical Science Beijing 100084 China School of Information Technologies University of Sydney NSW 2006 Australia department of Electronic and Information Engineering Hong Kong Polytechnic University Hong Kong

The inherent noise in positron emission tomography (PET) leads to the instability of quantitative indicators, which may affect the diagnostic accuracy for differentiating malignant and benign lesions in the management of lung cancer. In this paper, the reliability of retention index (RI) is systematically investigated by using computer simulation for the dual-time-point imaging protocol. The area under the receiver operating characteristic (ROC) curve is used to evaluate the optimal protocol. Results demonstrate that the reliability of RI is affected by several factors including noise level, lesion type, and imaging schedule. The RIs with small absolute values suffer from worse reliability than those larger ones. The results of ROC curves show that over delayed second scan cannot help to improve the diagnostic performance further, while an early first scan is expected. The method of optimization based on ROC analysis can be easily extended to comprise as many lesions as possible.

关键词： Reliability Retention index PET (positron emission tomography) Simulation ROC (receiver operating characteristic)

Development of planar patch clamp technology and its application in the analysis of cellular electrophysiology

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Progress in Natural Science:Materials International 2009年第2期19卷 153-160页

作者： Peihua Chena,Wei Zhang a,Jun Zhou a,Ping Wang a,Lidan Xiaob,Mo Yang b a Biosensor National Special Laboratory,Key Laboratory of Biomedical Engineering of Education Ministry,department of Biomedical Engineering,Zhejiang university,Hangzhou 310027,china b department of Health Technology and Informatics,The hong kong polytechnic university,Hung Hom,Kowloon,hong kong,china Biosensor National Special Laboratory Key Laboratory of Biomedical Engineering of Education Ministry Department of Biomedical Engineering Zhejiang University Hangzhou 310027 China department of Health Technology and Informatics The Hong Kong Polytechnic University Hung Hom Kowloon Hong Kong China

A patch clamp chip,as a novel cell-based chip for electrophysiological recordings,has many prominent advantages such as high res-olution,accuracy,high throughput and automation. It can be used to perform multivariate and real-time measurements of cell networks in situ. Therefore,this technology will dramatically promote the research on ionic channels,neuronal networks and the application of this technology in drug screening. This paper reviews the development of planar patch clamp technology and its applications in detail. The latest progress in the research of taste cells electrophysiology and taste transduction is also presented. Finally,this paper analyzes the methodology of neural chips. Based on the current research of our laboratory,the prospective applications of a patch clamp chip in the research of taste sensation and transduction mechanisms at molecular and cellular levels are discussed.

关键词： Patch clamp chip Cellular electrophysiology Taste Taste cell Taste transduction

A MUCLTI-PARAMETER SPLITTING EXTRAPOLATION AND A PARALLEL ALGORITHM

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Systems Science and Mathematical Sciences 1997年第3期10卷 253-260页

作者： ZHOU Aihui(Institute of Systems Science, Academia Sinica, Beijing 100080, china)Liem Chin-ho Shih Tsi-min(department of applied mathematics, hong kong polytechnic university, hong kong)LU Tao(Institute of Chengdu Computer Application, Academia Sinica, Ch

The finite element solutions of elliptic equations are shown to have a multiparameter asymptotic error expansion. Based on this expansion and a multi-parametersplitting extrapolation technique, a parallel algorithm fo... 详细信息

关键词： Finite element multi-parameter error expansion parallel algorithm multiparameter splitting extrapolation

Eigenvalues of Tensors and Their Applications in the Positive Definiteness Identification Problem

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Eigenvalues of Tensors and Their Applications in the Positiv...

Determination of Young's modulus by nanoindentation

2006年中国运筹学会数学规划分会代表会议暨第六届学术会议

作者： Liqun Qi (department of applied mathematics,The hong kong polytechnic university)

The study of positive definiteness of an even degree multivariate form arises from stability study of nonlinear autonomous systems via Liapunov’s direct method in automatic control and many other appl

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Science china(Technological Sciences) 2004年第4期47卷 398-408页

作者： MA Dejun1, Chung Wo Ong2, LIU Jianmin1 & HE Jiawen3 1. Surface Engineering Research Institute, CMES, Beijing 100072, china 2. department of applied Physics and Materials Research Center, the hong kong polytechnic university, hong kong, china 3. State Key Laboratory for Mechanical Behavior of Materials, Xian Jiaotong university, Xian 710049, china Surface Engineering Research Institute CMES Beijing China department of applied Physics and Materials Research Center The Hong Kong Polytechnic University Hong Kong China State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong University Xi’an China

A methodology for determining Youngs modulus of materials by non-ideally sharp indentation has been developed. According to the principle of the same area-to-depth ratio, a non-ideally pyramidal indenter like a Berkovich one can be approximated by a non-ideally conical indenter with a spherical cap at the tip. By applying dimensional and finite element analysis to the non-ideally conical indentation, a set of approximate one-to-one relationships between the ratio of nominal hardness/reduced Youngs modulus and the ratio of elastic work/total work, which correspond to different tip bluntness, have been revealed. The nominal hardness is defined as the maximum indentation load divided by the cross-section area of the conical indenter specified at the maximum indentation depth. As a consequence, Youngs modulus can be determined from a nanoindentation test only using the maximum indentation load and depth, and the work done during loading and unloading processes. The new method for determining Youngs modulus is referred to as pure energy method. The validity of the method was examined by performing indentation tests on five materials. The experimental results and the standard reference values are in good agreement, indicating that the proposed pure energy method is a promising substitution for the most widely used analysis models at present.

关键词： Young's modulus, nanoindentation, nominal hardness, indentation work.