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12th International Conference on Computer Methods and Advances in Geomechanics 2008

作者： Chen, Zheng-Han Lu, Zai-Hua Guo, Jianfeng Fang, Xiang-Wei Zhou, Hai-Qing Logistic Engineering University Chongqing China Key Lab. for the Exploitation of Southwest Resources Environment Disaster Control Engineering Ministry of Education Chongqing 1 China Navy University of Engineering Wuhan China

ISBN: (纸本)9781622761760

In order to investigate the sliding mechanism and process of expansive soil slope during digging and raining-evaporating courses, a FEM program named UESEPDC was designed based on the elasticity-plasticity-damage constitutive model and the elasticity-plasticity-damage consolidation model of unsaturated expansive soil proposed by the authors, and the numerical analysis on solid-liquid-gas tri-phases and multi-field couple problem was conducted for four stages: Raining and evaporating before digging;The moment at digging finishing;Three days after digging finishing;Multi- raining-evaporating cycles. The fields of stress, displacement, pore water pressure, pore air pressure, water content and suction in an expansive soil slope were obtained, and the pictures of crack damage evolution and plastic zone development in the same expansive soil slope for each analysis stage were shown. The research results clearly reveal the mechanism of expansive soil slope sliding progressively.

关键词： Numerical analysis

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Preparation and characterization of SiO2/stearic acid microencapsulated phase change materials

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Gongneng Cailiao/Journal of Functional Materials 2008年第12期39卷 2025-2027+2031页

作者： Jian, Shou-Wei Ma, Bao-Guo Jin, Lei Mu, Song Zhang, Qin Key Lab. for Silicate Materials Science and Engineering of Ministry of Education WHUT Wuhan 430070 China

The preparation of a new kind of SiO2/stearic acid microencapsulated phase change materials(microPCMs) which used sodium silicate and stearic acid as the basic raw materials was described in this paper. The progress of microPCMs which [SiO4] to the wall for stearic acid batteries can be divided into two steps. The first stearic dispersed method is through the reaction of surfactant between the water glass with stearic acid, the formation of MicroPCMs will be reached after the completion of pH value by adjusting the water glass to provide [SiO4], at the same time stearic acid reduced from stearic acid sodium salt. Based on this, some testing technology such as SEM of the surface, DSC of the thermal properties, XRD of core structure and FTIR of wall structure is used of micro-capsules evaluation. the result shows that the size of the micro-capsules has a particle size at 0.40-0.6μm, and a uniform, smooth surface, with a phase change enthalpy for 78.2J/g. The method get a better way to solve the organic phase change materials in the process of decentralization of the problem, not only reduced the preparation of the necessary materials types of raw materials, but also improved the effective content of phase change materials increased.

关键词： Phase change materials

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Individually prefabricated prosthesis for maxilla reconstruction

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Journal of Prosthodontics 2008年第2期17卷 135-140页

作者： Singare, Sekou Liu, Yaxiong Li, Dichen Lu, Bingheng Wang, Jue He, Sanhu Key Laboratory of Biomedical Information Engineering Xi'an Jiaotong University Ministry of Education Xi'an China State Key Lab. for Manufacturing Systems Engineering Xi'an Jiaotong University Xi'an China Department of Maxillofacial Surgery School of Stomatology Xi'an Jiaotong University Xi'an China Department of Mechatronic Engineering Dongguan University of Technology Guangdong China Key Laboratory of Biomedical Information Engineering Xi'an Jiaotong University Ministry of Education Xi'an 710049 China

The reconstruction of maxillofacial bone defects by the intraoperative modeling of implants may reduce the predictability of the esthetic result, leading to more invasive surgery and increased surgical time. To improve the maxillofacial surgery outcome, modern manufacturing methods such as rapid prototyping (RP) technology and methods based on reverse engineering (RE) and medical imaging data are applicable to the manufacture of custom-made maxillary prostheses. After acquisition of data, an individual computer-based 3D model of the bony defect is generated. These data are transferred into RE software to create the prosthesis using a computer-aided design (CAD) model, which is directed into the RP machine for the production of the physical model. The precise fit of the prosthesis is evaluated using the prosthesis and skull models. The prosthesis is then directly used in investment casting such as "Quick Cast" pattern to produce the titanium model. In the clinical reports presented here, reconstructions of two patients with large maxillary bone defects were performed using this new method. The custom prostheses perfectly fit the defects during the operations, and surgery time was reduced. These cases show that the prefabrication of a prosthesis using modern manufacturing technology is an effective method for maxillofacial defect reconstruction. © 2007 by The American College of Prosthodontists.

关键词： Computer-aided reconstruction Designed prosthesis Individual template Rapid prototyping Rapid tooling

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Object segmentation using graph cuts for the H.264 compressed video with moving background

Object segmentation using graph cuts for the H.264 compresse...

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2008 11th IEEE International Conference on Communication Technology, ICCT 2008

作者： Lu, Yu Zhang, Zhaoyang Liu, Zhi Shi, Xuli School of Communication and Information Engineering Shanghai University Shanghai China Key Lab. of Advanced Display and System Application Ministry of Education Shanghai University Shanghai China

ISBN: (纸本)9781424422517

This paper proposed a novel approach to segment objects from the H.264 compressed video with moving background. At first, the noisy motion vectors are eliminated from the motion field by vector median filtering. Then the predicted motion field reconstructed by backward estimation is used to accumulate the motion field, which is followed by global motion compensation. After that, the hypothesis testing is used for initial region classification. Finally, the graph cuts technique is applied to partition objects by minimizing the energy function formulated by the model of Markov Random Field. The experimental results demonstrate efficient performance and good segmentation quality of the proposed method. © 2008 IEEE.

关键词： Median filters

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Spectrum sensing, access and coexistence testbed for cognitive radio using USRP

Spectrum sensing, access and coexistence testbed for cogniti...

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2008 4th IEEE International Conference on Circuits and Systems for Communications, ICCSC

作者： Yan, Zhi Ma, Zhangchao Cao, Hanwen Li, Gang Wang, Wenbo Key Lab. of Universal Wireless Communications Ministry of Education School of Telecommunications Engineering Beijing University of Posts and Telecommunications Xitucheng Road No.10 Beijing 100876 China

ISBN: (纸本)9781424417087

The idea of cognitive radio has created a great interest in academic and industrial research recently. As a result, there are a large number of proposals for physical and network layer functionalities. In this paper, we demonstrate an experimental platform with the USRP board developed by Ettus Research that can facilitate the development of PHY and MAC layers functionality. Some key results from this experience so far are presented, including an over-the-air interoperability analysis of two different SDR (Software Defined Radio) architectures in the same frequency band, the effect of dynamic spectrum access on legacy systems and analysis of actual co-existence experiences involving primary users and secondary opportunistic spectrum users. In particular, we focus our attention on spectrum sensing and spectrum coexistence as an example that incorporates both digital signal processing and networking techniques to show how this platform could be used to conduct comprehensive research in cognitive radio. ©2008 IEEE.

关键词： Cognitive radio

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Automatic needle segmentation using 3D Gray-level Hough Transform in 3D ultrasound images

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Journal of Computational Information Systems 2008年第5期4卷 2021-2026页

作者： Qiu, Wu Ding, Mingyue Yuchi, Ming Image Processing and Intelligence Control Key Lab. of Education Ministry of China Institute of Pattern Recognition and Artificial Intelligence Huazhong University of Science and Technology Wuhan 430074 China Department of Biomedical Engineering School of Life Science and Technology Huazhong University of Science and Technology Wuhan 430074 China

This paper describes a novel 3D needle segmentation algorithm for 3DUS data. The algorithm includes the 3D Gray-level Hough Transform (3DGHT), which is based on the representation (ψ, θ, ρ, α) of straight lines in 3D space and Local Dimensionality Estimator (GST). Different from the traditional Hough transformation the process of binarization is not needed, because the proposed algorithm adopts the original gray level image directly. We tested it with the synthetic data and water phantom. The results show that our algorithm works well in 3D US images with angular deviation less than 1° and position deviation less than 1 mm. © 2008 Binary Information Press.

关键词： Hough transforms

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Model for cascading failures in congested Internet

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2008年第10期9卷 1331-1335页

作者： Jian WANG Yan-heng LIU Jian-qi ZHU Yu JIAO Key Lab of Symbolic Computation and Knowledge Engineering of Ministry of Education College of Computer Science and Technology Jilin University Changehun 130012 China

Cascading failures often occur in congested networks such as the Internet. A cascading failure can be described as a three-phase process: generation, diffusion, and dissipation of the congestion. In this account, we present a function that represents the extent of congestion on a given node. This approach is different from existing functions based on betweenness centrality. By introducing the concept of ''delay time'', we designate an intergradation between permanent removal and nouremoval. We also construct an evaluation function of network efficiency, based on congestion, which measures the damage caused by cascading failures. Finally, we investigate the effects of network structure and size, delay time, processing ability and packet generation speed on congestion propagation. Also, we uncover the relationship between the cascade dynamics and some properties of the network such as structure and size.

关键词： Complex network Cascading failures Congestion effects Propagation model

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The characterizations of bacterial cellulose and dialdehyde celluloses from bacterial cellulose

The characterizations of bacterial cellulose and dialdehyde ...

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作者： Yuhong, Feng Jiacheng, Li Qiang, Lin Sujuan, Pang Xibin, Wang Zhouxin, Wu Key Lab. of Hainan Finechemicals Hainan University Chinese Education Ministry Haikou 570228 China Faculty of Land Resource Engineering Kunming University of Science and Technology Kunming 650093 China

The characteristics and properties of bacterial cellulose and dialdehyde celluloses from bacterial cellulose were studied by XRD, TG-IR and adsorption capacity testing. The crystal cell parameters of BC were calculated and approximated to that of monocline crystal cell model. The XRD profiles showed that the crystallinity degree of BC was 66%, and that of the DACs (12% aldehyde) was 56%. The optimal adsorption capacities of pure water on dried BC and DAC were 12 g/g and 3.1 g/g respectively, and that of iron ion on dried BC and DAC were 11 mg/g and 6.9 mg/g respectively. And the optimal adsorption capacity of hexanediamine on DAC was 700 mg/g, and that of n-phenylene diamine on DAC was 490 mg/g. The IR result showed that the adsorption of hexanediamine on DAC was physical adsorption, not chemical reaction under the experimental conditions.

关键词： Cellulose

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Determination methods of dialdehyde celluloses from bacterial cellulose

Determination methods of dialdehyde celluloses from bacteria...

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作者： Feng, Yuhong Li, Jiacheng Lin, Qiang Pang, Sujuan Zhang, Mengying Wang, Xibin Wu, Zhouxin Sun, Zhongliang Faculty of Land Resource Engineering Kunming University of Science and Technology Kunming 650093 China Key Lab. of Tropic Biological Resource Hainan University Chinese Education Ministry Haikou 570228 China

This paper addresses the determination of aldehyde group (% of dialdehyde units) in dialdehyde cellulose (DACs) oxidized from bacterial cellulose (BC). With 4 determination methods, the oxidation degrees of DACs were studied: Automatic potential titration method through Schiff base reaction, Acid-base titration in Cannizzaro reaction, Metaperiodate consumption determination, and Measurement of amino nitrogen content in DAC derivatives. By comparing determination results of these methods, we found out the proper way suitable for this metaperiodate oxidation system of BC to measure the dialdehyde unit content of the DACs.

关键词： Cellulose

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Ultrasonic features in wire bonding and thermosonic flip chip

Ultrasonic features in wire bonding and thermosonic flip chi...

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2008 International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2008

作者： Junhui, Li Lei, Han Jue, Zhong School of Mechanical and Electronical Engineering Central South University ChangSha 410083 China Key Laboratory of Modern Complex Equipment Design and Extreme Manufacturing Ministry of Education ChangSha 410083 China State Key Lab. of Digital Manufacturing Equipment and Technology Wuhan 430074 China

ISBN: (纸本)9781424427406

Driving voltage and current signals of Piezoceramic Transducer (PZT) were measured directly by designing circuits from ultrasonic generator and using a data acquisition software system. Input impedance and power of PZT were investigated by using Root Mean Square (RMS) calculation. Vibration driven by high frequency was tested by laser Doppler vibrometer (PSV-400-M2). Thermosonic bonding features were observed by scanning electron microscope (JSM-6360LV). Results show that the input power of bonding is lower than that of no load. The input impedance of bonding is greater than that of no load. Nonlinear phase, plastic flow and expansion period, and strengthening process were shown in impedance and power curves. The ultrasonic power is proportion to vibration displacement driven by the power, and greater displacements driven by high-power result in welding failure phenomena, such as crack, break, and peel off in wedge bonding,. For thermosonic flip chip bonding, the high power decreases position precision of bonding or results in slippage and rotation phenomena of bumps. To improve reliability and precision of thermosonic bonding, the low ultrasonic power should be chosen. © 2008 IEEE.

关键词： Scanning electron microscopy

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