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Virtual reality mobility model for wireless ad hoc networks

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Journal of Systems Engineering and Electronics 2008年第4期19卷 819-826页

作者： Yu Ziyue gong bo He Xingui School of Computer Science & Engineering Beijing Univ. of Aeronautics and Astronautics Beijing 100083 P. R. China Inst. of Command and Technology of Equipment Beijing 101416 P. R. China School of Electronics Engineering and Computer Science Peking Univ. Beijing 100871 P. R. China

For wireless ad hoc networks simulation, node＇s mobility pattern and traffic pattern are two key elements. A new simulation model is presented based on the virtual reality collision detection algorithm in obstacle environment, and the model uses the path planning method to avoid obstacles and to compute the node＇s moving path. Obstacles also affect node＇s signal propagation. Considering these factors, this study implements the mobility model for wireless ad hoc networks. Simulation results show that the model has a significant impact on the performance of protocols.

关键词： wireless ad hoc networks computer simulation network protocols mobility models

Growing actin networks regulated by obstacle size and shape

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Acta Mechanica Sinica 2017年第2期33卷 222-233页

作者： bo gong Ji Lin Jin Qian Department of Engineering Mechanics Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Zhejiang University Hangzhou 310027 China

Growing actin networks provide the driving force for the motility of cells and intracellular pathogens. Based on the molecular-level processes of actin polymerization, branching, capping, and depolymerization, we have developed a modeling framework to simulate the stochastic and cooperative behaviors of growing actin networks in propelling obstacles, with an emphasis on the size and shape effects on work capacity and filament orientation in the growing process. Our results show that the characteristic size of obstacles changes the protrusion power per unit length, without influencing the orientation distribution of actin filaments in growing networks. In contrast, the geometry of obstacles has a profound effect on filament patterning, which influences the orientation of filaments differently when the drag coefficient of environment is small, intermediate, or large. We also discuss the role of various parameters, such as the aspect ratio of obstacles, branching rate, and capping rate, in affecting the protrusion power of network growth.

关键词： Actin network Growth dynamics Monte Carlo simulation Size effect Shape effect

Raman spectroscopy monitors adverse bone sequelae of cancer radiotherapy

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Chinese Chemical Letters 2015年第4期26卷 401-406页

作者： bo gong Michael D.Morris Department of Chemistry College of LiteratureScience and the ArtsUniversity of Michigan

Raman spectroscopy provides information on bone chemical composition and structure via widely used metrics including mineral to matrix ratio, mineral crystallinity and carbonate content, collagen cross- linking ratio and depolarization ratios. These metrics are correlated with bone material properties, such as hardness, plasticity and Young＇s modulus. We review application of Raman spectroscopy to two important irradiated animal models： the mouse tibia, a model for damage to cortical bone sites including the rib （breast cancer） and to healthy tissue adjacent to extremity sarcomas, and the rat mandible, a model for radiation damage in head and neck cancer radiotherapy. Longitudinal studies of irradiated mouse tibia demonstrate that radiation-induced matrix abnormalities can persist even 26 weeks post- radiation. Polarized Raman spectroscopy shows formation of more ordered orientation of both mineral and collagen. At 8 weeks post-radiation, irradiated rat hemimandible exhibits transient hyperminer- alization, increased collagen cross-linking and decreased depolarization ratios of mineral and collagen. A standard radioprotectant, amifostine, mitigates rat mandible radiation damage, with none remaining detectable 18 weeks post-radiation. Already a powerful tool to monitor radiation damage, Raman spectroscopy may be important in development of new radiotherapy protocols and radioprotective agents. Further in vfvo studies of radiation effects on the rodent models are underway, as are development of methodologies for eventual use in human subjects.

关键词： boneRaman spectroscopyCancer radiotherapy

A Method for Obtaining Integrable Couplings

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Communications in Theoretical Physics 2006年第6期45卷 1000-1002页

作者： ZHANG Yu-Sen CHEN Wei LIAO bo gong Xin-bo Department of Mathematics Shandong University at Weihai Weihai 264209 China School of Computer and Communication Hunan University Changsha 410082 China Information School Shandong University of Science and Technology Qingdao 266510 China

By making use of the vector product in R^3, a commuting operation is introduced so that R^3 becomes a Lie algebra. The resulting loop algebra R^-3 is presented, from which the well-known AKNS hierarchy is produced. Again via applying the superposition of the commuting operations of the Lie algebra, a commuting operation in R^6 is constructed so that R^6 becomes a Lie algebra. Thanks to the corresponding loop algebra R^3 of the Lie algebra R^3, the integrable coupling of the AKNS system is obtained. The method presented in this paper is rather simple and can be used to work out integrable coupling systems of the other known integrable hierarchies of soliton equations.

关键词： AKNS hierarchy integrable couplings Lie algebra

Simulations of thermal conductance across tilt grain boundaries in graphene

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Acta Mechanica Sinica 2012年第6期28卷 1528-1531页

作者： Peng Wang bo gong Qiong Feng Hong-Tao Wang Institute of Applied Mechanics Zhejiang University

Non-equilibrium molecular dynamics （MD） method was performed to simulate the thermal transporta- tion process in graphene nanoribbons （GNRs）. A convenient way was conceived to introduce tilt grain boundaries （GBs） into the graphene lattice by repetitive removing C atom rows along certain directions. Comprehensive MD simulations reveal that larger-angle GBs are effective thermal barriers and substantially reduce the average thermal conductivity of GNRs. The GB thermal conductivity is ~ 10 W-m-1 .K-l for a bicrystal GNR with a misorientation of 21.8%, which is -97 % less than that of a prefect GNR with the same size. The total thermal resistance has a monotonic dependence on the den- sity of the 5-7 defects along the GBs. A theoretical model is proposed to capture this relation and resolve the contribu- tions by both the reduction in the phonon mean free path and the defect-induced thermal resistance.

关键词： Graphene Thermal conductivity Grain bound-ary

The Time and Cost Prediction of Tunnel boring Machine in Tunnelling

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Wuhan University Journal of Natural Sciences 2006年第2期11卷 385-388页

作者： WU Shijing QIAN bo gong Zhibo School of Power and Mechanical Engineering Wuhan University Wuhan 430072 Hubei China

Making use of microsoft visual studio. net platform, the assistant decision-making system of tunnel boring machine in tunnelling has been built to predict the time and cost. Computation methods of the performance parameters have been discussed. New time and cost prediction models have been depicted. The multivariate linear regression has been used to make the parameters more precise, which are the key factor to affect the prediction near to the reality.

关键词： tunnel boring machine time prediction costprediction assistant decision-making multivariate linear regression

EFFECT OF HYDROGEN ON HIGH TEMPERATURE PLASTICITY OF Ti-6Al-4V ALLOY

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Acta Metallurgica Sinica(English Letters) 1992年第1期5卷 21-24页

作者： XU Zhensheng gong bo ZHANG Caibei LAI Zuhan Northeast Univ of Technology Shenyang China

The effects of various hydrogen contents on the flow stress(σ),strain rate sensitivity expo- nent(m)and the tensile elongation(δ)of Ti-6Al-4V alloy were *** microstructure of the alloy was also *** results indicate that,a suitable amount of hydrogen in the alloy can reduce the flow stress in the temperature range 800—860℃. Consequently,the superplastic temperature can be decreased and the ductility improved.

关键词： Hydrogen Ti-6Al-4V alloy strain rate sensitivity exponent high temperature ductility

An Improved Car-Following Model for Multiphase Vehicular Traffic Flow and Numerical Tests

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Communications in Theoretical Physics 2006年第2X期46卷 367-373页

作者： LI Zhi-Peng gong Xiao-bo LIU Yun-Cai Institute of Image Processing and Pattern Recognition Shanghai Jiaotong University Shanghai 200240 China

This paper attempts to introduce an improved difference model that modifies a car-following model, which takes the next-nearest-neighbor interaction into account. The hnprovement of this model over the previous one lies in that it performs more realistically in the dynamical motion for small delay time. The traffic behavior of the improved model is investigated with analytic and numerical methods with the finding that the new consideration could further stabilize traffic flow. And some simulation tests verify that the proposed model can demonstrate some complex physical features observed recently in real traffic such as the existence of three phases： free flow, coexisting flow, and jam flow; spontaneous formation of density waves; sudden flow drop in flow-density plane; traffic hysteresis in transition between the free and the coexisting flow. Furthermore, th.e improved model also predicts that the stable state to relative density in the coexisting flow is insusceptible to noise.

关键词： car-following models density waves traffic flow

A cellular scale numerical study of the effect of mechanical properties of erythrocytes on the near-wall motion of platelets

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Acta Mechanica Sinica 2014年第2期30卷 274-280页

作者： Jing Xu Xiao-Long Wang Yun-Qiao Liu Xiao-bo gong MOE Key Laboratory of Hydrodynamics Department of Engineering MechanicsShanghai Jiao Tong University SJTU-CU ICRC Shanghai Jiao Tong University

The effect of mechanical properties of erythrocytes on the near-wall motion of platelets was numerically studied with the immersed boundary method. Cells were modeled as viscous-fluid-filled capsules surrounded by hyper-elastic membranes with negligible thickness. The numerical results show that with the increase of hematocrit, the near-wall approaching of platelets is enhanced, with which platelets exhibit larger deformation and orientation angle of its near-wall tank-treading motion, and the lateral force pushing platelets to the wall is increased with larger fluctuation amplitude. Meanwhile the near-wall approaching is reduced by increasing the stiffness of erythrocytes.

关键词： Hemodynamics Fluid-membrane interaction Immersed boundary method Near-wall motion of platelet