检索结果-南通市图书馆

NUMERICAL SIMULATION OF SEPARATED FLOW NEAR GROYNE

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2002年第4期14卷 47-52页

作者： Jiang, Chang-Bo Chen, Yong-Kuan Bai, Yu-Chuan Zhao, Zi-Dan Dept. of River and Coast eng. Changsha Commun. Univ. Changsha 410076 China Dept. of Hydraulic eng. Tsinghua Univ. Beijing 100084 China Inst. of sediment on River eng. Tianjian Univ. Tianjian 300072 China

A numerical model was developed to simulate the flow around non-submeged groyne in two dimensions, which was based on N-S equations with Smagorinsky's subgrid-scale turbulence model. Flow phenomenon and results measured practically agree with the calculation results very well, and this model could be used to simulate the characteristics of the eddies of upper and down reaches around spur-dikes successfully.

关键词： Computational fluid dynamics Computer simulation Erosion Mathematical models Navier Stokes equations Turbulent flow

Evaluation of Dynamic Soil-Structure Interaction and Dynamic Seismic Soil Pressures Acting on It Subjected to Strong Earthquake Motions

在线全文

学校读者我要写书评

暂无评论

Journal of Shanghai Jiaotong university(Science) 2006年第4期11卷 530-536页

作者：车爱兰 IWATATE Takahiro 葛修润 School of Naval Architecture Ocean and Civil Eng. Shanghai Jiaotong Univ. Civil and Environmental eng. Tokyo Metropolitan Univ.

In order to clarify the damage mechanism of the subway structure, the dynamic soil-structure interaction and the dynamic forces acting on the structure, a series of shaking table tests and simulation analyses were performed. The seismic response of the structure and the dynamic forces acting on the structure due to sinusoidal and random waves were investigated with special attention to the dynamic soil-structure interaction. The result shows that the compression seismic soil pressures and extension seismic soil pressures simultaneously act on the sidewalls, and big shear stress also acts on the ceiling slab due to horizontal excitation. The seismic soil pressure could be approximated to hyperbola curve, and reached a peak value with increase of the shear strain of the model ground. In addition, a slide and exfoliation phenomenon between the structure and the surrounding ground was simulated, using the nonlinear analyses. The foundation is provided for amending the calculation method of seismic soil pressure and improving the anti-earthquake designing level of underground structure.

关键词： subway structure dynamic seismic soil pressure dynamic soil-structure interaction shaking table tests dynamic analyses nonlinear characteristics

An Adaptive Joint Source/Channel Coding Using Error Correcting Arithmetic Codes

在线全文

学校读者我要写书评

暂无评论

Journal of Shanghai Jiaotong university(Science) 2007年第4期12卷 448-453页

作者：刘军清逄玉叶孙军 Dept.of Electronic eng. China Three Gorges Univ. Dept.of Electronic eng. Shanghai Jiaotong Univ.

An approximately optimal adaptive arithmetic coding (AC) system using a forbidden symbol (FS) over noisy channels was proposed which allows one to jointly and adaptively design the source decoding and channel correcting in a single process, with superior performance compared with traditional separated techniques. The concept of adaptiveness is applied not only to the source model but also to the amount of coding redundancy. In addition, an improved branch metric computing algorithm and a faster sequential searching algorithm compared with the system proposed by Grangetto were proposed. The proposed system is tested in the case of image transmission over the AWGN channel, and compared with traditional separated system in terms of packet error rate and complexity. Both hard and soft decoding were taken into account.

关键词： arithmetic coding joint source channel coding maximum a posteriori (MAP) forbidden symbol

Removal of Anionic Metal Ions from Wastewater by Hydroxide-type Adsorbents

在线全文

学校读者我要写书评

暂无评论

过程工程学报 2006年第3期6卷 357-362页

作者： Toyohisa Fujita Gjergj Dodbiba Jun Sadaki Atsushi Shibayama Dept. Geosystem eng. Graduate School Eng.The University of TokyoTokyo 113-8654Japan Dept. Material-Process. eng.&Appl. Chem. for Environ. Faculty Eng.&Resources Sci.Akita Univ.Akita 010-8502Japan

Generally speaking,anionic metal concentrations in wastewater from industries and mineral processing plants are well above the allowed limits for effluent set by the Ministry of Environment of Japan. Nowadays,the removal of anionic ions has been considered difficult and development of new process is desperately needed. In this paper,we report the development of three hydroxide-type adsorbents,illustrating their adsorption efficiency in removing As,Se,Mo and Sb ions from aqueous solutions. The main finding of this work was that the adsorption behavior was influenced very much by both the pH and the adsorbent concentration. Nevertheless,the newly developed hydroxide-type adsorbents were very effective in reducing the concentration of those anionic ions.

关键词： hydroxide-type adsorbent adsorption anionic metal ions removal wastewater

Monitoring Thermal Coagulation with Ultrasonic Textures

在线全文

学校读者我要写书评

暂无评论

Journal of Shanghai Jiaotong university(Science) 2007年第4期12卷 530-536页

作者：阳维张素陈亚珠陈磊胡兵马维银 Dept.of Biomedical eng. Shanghai Jiaotong Univ. Sixth People's Hospital Shanghai Jiaotong Univ. Dept.of Manu. eng. & eng. Man. City Univ.of Hong Kong

The feasibility of using B-mode ultrasound image textures and pattern recognition technique to characterize the thermal coagulation in vitro during radiofrequency ablation was investigated. The changes of ultrasonic textures in the different regions of samples varied with the heating time in the in-vitro experiments, which would result in that the coagulated and noncoagulated regions of tissue had different ultrasonic textures. Using support vector machine to extract the ultrasonic texture features and characterize the state of tissue, the size and boundaries of thermal lesions could be detected and measured more exactly than only using the gray scale information of B-mode ultrasound image. The proposed method would be applied to the image-guided radiofrequency ablation (IGRA) procedure for monitoring the thermal coagulation.

关键词： thermal lesion ultrasonic texture radiofrequency ablation support vector machine

Semi-blind Channel Estimator for OFDM-STC

在线全文

学校读者我要写书评

暂无评论

Journal of Shanghai Jiaotong university(Science) 2007年第2期12卷 229-233页

作者：吴赟罗汉文宋文涛黄建国 Dept.of Electronic eng. Shanghai Jiaotong Univ. Col.of Marine eng. Northwestern Polytechnical Univ.

Channel state information of OFDM-STC system is required for maximum likelihood decoding.A subspace-based semi-blind method was proposed for estimating the channels of OFDM-STC *** channels are first estimated blindly up to an ambiguity parameter utilizing the nature structure of STC,irrespective of the underlying signal ***,a method was proposed to resolve the ambiguity by using a few pilot *** simulation results show the proposed semi-blind estimator can achieve higher spectral efficiency and provide improved estimation performance compared to the non-blind estimator.

关键词： channel estimation OFDM-STC semi-blind subspace-based

Microstructural Features During Strain Induced Ferrite Transformation in 08 and 20Mn Steels

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2001年第2期8卷 105-110页

作者： Ping Yang, Feng.e Cui, Fuming Wang (Materials Science and eng.neering School, University of Science and Technology Beijing, Beijing 100083, China) (Metallurgy School, University of Science and Technology Beijing, Beijing 100083, China) Materials Sci. and eng. School University of Science and Technology Beijing 100083 China

The microstructure evolution during strain induced ferrite transformation was followed in thermal-simulation tests of clean 08 and 20Mn steels. The influences of carbon equivalence and initial austenite grain size on ferrite grain refinement and the volume fraction of ferrite during straining were inspected. The results revealed that the accelerating effect of ferrite transformation by strain was increased as the carbon equivalence decreased. However, finer ferrite grains were obtained at higher carbon content. At strain of similar to1.5 ferrite grains less than 3 mum and 2 mum can be obtained in 08 and 20Mn steels respectively. Whereas the ferrite grain refinement in 08 steel was due to both effects of strain induced transformation and ferrite dynamic recrystallization, that in 20Mn was mainly due to strain induced transformation. Heavy strain can produce fine ferrite grains in coarse austenite grained 08 steel, but it would lead to band microstructure in coarse austenite grained 20Mn.

关键词： clean carbon steel strain induced transformation grain refinement ferrite dynamic recrystallization

WiSeREmulator: An Emulation Framework for Wireless Structural Health Monitoring

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2015年第4期20卷 317-326页

作者： Rajat Khanda Rong Zheng.Gangbing Song Department of Electrical eng. University of Houston Department of Computing and Software Mc Master University

Many competing approaches exist in evaluating sensor network solutions differing by levels of ease of use, cost, control, and realism. Existing work concentrates on simulating network protocols or emulating processing units at the machine cycle level. However, little has been done to emulate the sensors and the physical environments that they monitor. The main contribution of this work is the design of WiserEmulator, an emulation framework for structural health monitoring, which gracefully balances the trade-offs between realism, controllability, and cost. WiserEmulator consists of two main components -- a testbed of wireless sensor nodes and a software emulation environment. To emulate the excitation and response of piezo-electric transducers, as well as the wave propagation inside concrete structures, the COMSOL Multi-Physics software was utilized. Digitized sensing output from COMSOL was played back via a multi-channel Digital-to-Analog Converter （DAC） connected to the wireless sensor testbed. In addition to the emulation of concrete structures, WiSeREmulator also allows users to choose pre- stored data collected from field experiments and synthesized data. A user-friendly Graphical User Interface （GUI） was developed that facilitates intuitive configurations of experimental settings, control of the on-set and progression of the experiments, and real-time visualization of experimental results. We have implemented WiSeREmulator in MATLAB. This work advances the state of the art in providing low cost solutions to evaluating Cyber Physical Systems such as wireless structural health monitoring networks.

关键词： structure health monitoring cyber physical systems emulater

Wenchuan Post-earthquake Reconstruction by Utilizing Composite Tubular Construction and FRP Retrofitting Technology

在线全文

学校读者我要写书评

暂无评论

四川大学学报（工程科学版） 2009年第3期41卷 231-247页

作者： ZHAO X L AL-MAHAIDI R Dept. of Civil eng. Monash Univ. Clayton VIC 3800 Australia

This paper presents two possible construction methods that could be adopted in the Wenchuan post-earthquake *** is the composite tubular construction and the other is FRP(Fibre Reinforced Polymer) retrofitting *** background of these two methods,the existing research and relevance to Whenchuan post-earthquake reconstruction are described.

关键词：抗振结构建筑结构建筑物 FRP 地震重建