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2nd International Conference on Vulnerability and Risk Analysis and Management, ICVRAM 2014 and the 6th International Symposium on Uncertainty Modeling and Analysis, ISUMA 2014

作者： Li, H.S. Ma, Y.Z. Cao, Z. Key Lab. of Fundamental Science for National Defense-Advanced Design Technology of Flight Vehicles Nanjing University of Aeronautics and Astronautics Nanjing210016 China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan430072 China

ISBN: (纸本)9780784413609

Subset Simulation provides an efficient and robust method to estimate the failure probabilities at small probability levels for a single failure mode defined by the system response concerned. However, estimating failure probabilities of multiple stochastic responses using a single run of Subset Simulation remains quite a challenging task in structural reliability analysis. To address this problem, this study develops a generalized Subset Simulation (GSS) approach, in which a unified intermediate event is defined to drive the simulation procedure progressively approaching multiple failure regions, and estimate the corresponding failure probabilities simultaneously. The sorting difficulty arising in the multiple stochastic responses is bypassed by the definition of the unified intermediate event. Finally, two representative examples are used to demonstrate the performance of the proposed GSS approach. © 2014 American Society of Civil Engineers.

关键词： reliability analysis

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Simulation Study for a New Magnetic Induction Tomography Coil System with Weakly Perturbing in Conducting Background

Simulation Study for a New Magnetic Induction Tomography Coi...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society

作者： Ziyi Zhang Peiguo Liu Dongming Zhou Liang Zhang Hengdong Lei College of Science National University of Defense Technology State Key Laboratory of Complex Electromagnetic Environmental Effects on Electronics & Information System National University of Defense Technology

ISBN: (纸本)9781424479276

Biomedical magnetic induction tomography (MIT) aims to reconstruct the passive electrical properties within biological tissues, especially the electrical conductivity. A weak perturbation inside a conducting object is put in the improved MIT coil system which uses the two-arm Archimedean spiral coil as the excitation coil and the circular coil as the receiver coil. The forward problem for this model is calculated by three-dimension electromagnetic simulation experiments. Under the different simulation conditions, the phase shift of voltage induced in the receiver coil is compared with that for the common model using the circular coil as the excitation and receiver coil. The results show that the sensitivity to the improved model is much higher than that to the common model except for the case that the perturbation appears in y-axis, which effectively confirms the previous conclusions and indicates that the improved coil system has the potential advantage for MIT image reconstruction.

关键词： Augmented reality Cameras Geometry Computer vision Google Abstracts Mobile communication

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System reliability analysis of slopes considering spatial variability of soil properties

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Yingyong Jichu yu Gongcheng Kexue Xuebao/Journal of Basic science and engineering 2014年第5期22卷 841-855页

作者： Jiang, Shuihua Li, Dianqing Cao, Zijun Zhou, Chuangbing Zhang, Limin State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan430072 China Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering Ministry of Education Wuhan University Wuhan430072 China Department of Civil and Environmental Engineering The Hong Kong University of Science and Technology Hong Kong999077 Hong Kong

The paper aims to propose an effective method for evaluating the system reliability of soil slopes based on the multiple stochastic response surface method considering the spatial variability of soil properties. A new approach for identifying the representative slip surfaces is also suggested. The Karhunen-Loève expansion method is employed to discretize the two-dimensional cross-correlated non-Gaussian random fields of soil properties. The factor of safety of each representative slip surface is explicitly expressed as function of input uncertain parameters using the Hermite polynomial chaos expansion. The direct Monte-Carlo simulation is then employed to calculate the system probability of slope failure based on these representative slip surfaces. Two examples of system reliability analysis of slopes with a consideration of spatially varying soil properties are finally presented to demonstrate the validity and capability of the proposed method. The results indicate that the proposed method can provide an effective tool for evaluating the system reliability of slopes considering the spatial variability of soil properties. The proposed approach for determining representative slip surfaces can not only avoid tedious procedures of calculating the correlations between the factors of safety of any two potential slip surfaces, but also effectively evaluate system reliability of slopes at relatively small probability levels. The system probability of slope failure increases with increasing the variability and vertical autocorrelation distance, while decreases as the negative correlation of shear strength parameters becomes strong. In addition, it will lead to overestimating the system probability of slope failure if the spatial variability of soil properties is ignored.

关键词： reliability analysis

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Study of uptake and accumulation characteristic of U and Cd combined stress for wheat

Study of uptake and accumulation characteristic of U and Cd ...

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International Conference on Electrical Information and Mechatronics, ICEIM 2012

作者： Yan, Zhang Dan, Wang College of Life Science and Engineering Southwest University of Science and Technology Mianyang China Defense Key Discipline Laboratory of the Nuclear Waste Environmental Security Mianyang China

ISBN: (纸本)9783037856901

Water culture experiment was adopted to investigate the effects of U and Cod combined stress at different concentrations on the uptake and accumulation of U and Cod and physiological and biochemical characteristics in wheat seedlings. The experiment results showed that the U and Cod uptake by wheat seedlings was higher in roots than in aboveground parts when the total concentration of U and Cod was 5 mg/kg or 20 mg/kg, and the transfer factors (TFs) of U and Cod in wheat seedlings were above 1 when the total concentration was 100 mg/kg. But low concentration of U ad Cod were rarely accumulated in wheat seedlings, indicating that wheat seedlings have good tolerance to U and Cod combined stress at low concentration. The experiment results also showed that with the increase in the total concentration of U and Cod, the root activity of wheat seedlings first increased and then decreased, and it exhibited a significant increase when the concentration was 20 mg/kg. Also, with the increase in concentration, the chlorophyll content of wheat seedlings first increased and then decreased, while the SOD activity first decreased and then increased. © (2013) Trans Tech Publications, Switzerland.

关键词： Plants (botany)

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Simplified Reflection Models of Representative Ground Metal Target in Millimeter Wave Passive Surveillance

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高电压技术 2013年第10期39卷 2409-2414页

作者： WENG Xiaodi LU Xuliang TIAN Yu SUI Mingxu LI Yupeng Key Laboratory of Science and Technology on Electromagnetic Environmental Effects and Electro-optical Engineering PLA University of Science and Technology Nanjing 210007 China Jiangsu Key Laboratory of Spectral Imaging & Intelligent Sense Nanjing University of Science and Technology Nanjing 210094 China School of Computer Science National University of Defense Technology Changsha 410073 China

For designing camouflage of ground metal target against millimeter wave(MMW) passive detections,based on the radiation and reflection theories related to MMW passive detection and an assumption of high frequency approximation,simplified models of two kinds of ground metal targets are *** indicates that the reflection from ground is the leading factor on a ground metal target's radiant *** an 8-mm imaging experiment,the uneven distribution of radiant temperatures in horizontal and vertical metal plates is directly *** a radiometer experiment,two positions of a radiometer device are utilized to obtain the radiant temperatures of a horizontal metal in two different grounds(made of asphalt and metal net respectively),which are 295.41 K and 301.55 K,*** experimental results are close to the analytical results calculated from the proposed simplified models,which are 306 K and 296 K,*** to the simplified models,different parts of a vertical plate receive incident MMW of different angles from the asphalt *** radiant temperature of a vertical metal plate obtained from a radiometer experiment at night is 307 K,and it is in coherent with 304.22 K,the result from calculation using the simplified model of vertical *** the analytic results and the experimental results agree with the uneven distribution of radiant temperature.

关键词：金属目标毫米波模型辐射温度成像实验不均匀分布地面反射垂直方向

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Effect of pH to adsorption behavior of Pu on bentonite in aqueous environment

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Yuanzineng Kexue Jishu/Atomic Energy science and technology 2013年第4期47卷 523-528页

作者： Wang, Xiao-Qiang Li, Ping-Chuan Leng, Yang-Chun Tuo, Xian-Guo Su, Ji-Long Yue, Ping College of Nuclear Technology and Automation Engineering Chengdu University of Technology Chengdu 610059 China Sichuan Environmental Protection Engineering Co. Ltd. China National Nuclear Corporation Guangyuan 610006 China Laboratory of National Defense for Radioactive Waste and Environmental Security Southwest University of Science and Technology Mianyang 621010 China State Key Laboratory of Geoharzard Prevention and Geoenvironment Protection Chengdu University of Technology Chengdu 610059 China

The effects of pH to the adsorption behavior of Pu in GMZ-bentonite, Lingshou Ca-bentonite, Na-bentonite and bleaching earth were tested by static adsorption experiments in aqueous environment. The results show that the adsorption equilibrium time of Pu is four days in GMZ-bentonite and 5-6 days in bleaching earth, Ca-bentonite and Na-bentonite. In aqueous environment, the adsorption capacity of bentonite to Pu increases with pH in water phase, and it is weak in acidic aqueous environment and strong in alkaline aqueous environment extremely.

关键词： Bentonite

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Time-variant serviceability reliability analysis of anchored rock slopes deformation

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Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and engineering 2013年第6期32卷 1270-1278页

作者： Jiang, Shuihua Peng, Ming Li, Dianqing Zhang, Limin Zhou, Chuangbing State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan Hubei 430072 China Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering Ministry of Education Wuhan University Wuhan Hubei 430072 China Department of Civil and Environmental Engineering The Hong Kong University of Science and Technology Kowloon Hong Kong

A non-intrusive stochastic finite element method for time-variant serviceability reliability analysis of anchored rock slopes with consideration of rock bolt corrosion is proposed. A rock bolt corrosion model reflecting the variation of the anchored force of each rock bolt with service time is established. Consequently, the computational procedure for time-variant serviceability reliability analysis of the slope deformation using the non-intrusive stochastic finite element method is proposed. The relationship between the probability of failure for slope deformation and the maximum allowable deformation is investigated;and a method for determining the maximum allowable deformation of the slope is proposed based on parametric sensitivity analysis. An example of reliability analysis of anchored rock slope deformation subjected to surcharge loading is illustrated to demonstrate the validity and capability of the proposed method. The results indicate that the proposed non-intrusive stochastic finite element method can effectively evaluate time-variant serviceability reliability of rock slopes. The rock bolt corrosion has a significant influence on the serviceability reliability of rock slopes as the service time of rock bolts increases. In addition, an approximate linear relationship exists between the logarithm of the time-variant probability of failure for slope deformation, lgpf, and the maximum allowable deformation;and this linear relationship becomes more obvious as the reliability level of the slope increases.

关键词： reliability analysis

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System reliability analysis of rock slopes considering rock bolt corrosion

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Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and engineering 2013年第6期32卷 1137-1144页

作者： Li, Dianqing Jiang, Shuihua Zhang, Limin Zhou, Chuangbing State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan Hubei 430072 China Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering Ministry of Education Wuhan University Wuhan Hubei 430072 China Department of Civil and Environmental Engineering The Hong Kong University of Science and Technology Kowloon Hong Kong

A large number of engineering accidents have demonstrated that the failures of rock bolts are mainly induced by the corrosion of reinforcing steel bars. This study aims to investigate the effect of rock bolt corrosion on the system reliability of anchored rock slopes. A uniform corrosion model for rock bolts and its applicable environmental conditions are first examined based on systematical analysis of the existing corrosion models for reinforcing steel bars and the experiment data for rock bolt corrosion. Two failure modes related to rock bolt corrosion are determined. They are the yield failure mode of rock bolts at free section and the bond failure mode at the bolt-grout interface, respectively. Then, the failure models of anchored rock slope corresponding to those of rock bolts are established. A method for estimating the time-variant system reliability of rock slopes based on Monte Carlo simulation is presented. Consequently, an example of anchored rock slope with a single slip surface is presented to demonstrate the validity and capability of the proposed methods. The results indicate that the corrosion model proposed by K. A. T. Vu and M. G. Stewart is suitable for rock bolts subjected to environmental conditions of humidity and drying/wetting cycles. The rock bolt corrosion at free section has a more significant influence on the stability of rock slopes at the early stage, whereas the effect of rock bolt corrosion at anchored section becomes more obvious at the later stage. Moreover, the variations in the anchored force of each rock bolt and the system probability of slope failure at the later stage are more significant than those at the early stage. The system probability of slope failure decreases with the increasing thickness of the rock bolt cover, while increases with the increasing water-to-cement ratio of the grout. However, the system probability of slope failure does not significantly increase with time, when the thickness of the rock bolt cover an

关键词： Rocks

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New methodology for creating probit models to assess the domino effect caused by overpressure

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Dongbei Daxue Xuebao/Journal of Northeastern University 2013年第SUPPL.1期34卷 265-272页

作者： Sun, Dong-Liang Huang, Guang-Tuan Jiang, Jun-Cheng Zhang, Ming-Guang Wang, Zhi-Rong State Environ Protection Key Lab of Environmental Risk Assessment and Control on Chemical Process School of Resources and Environmental Engineering East China University of Science and Technology Shanghai 200237 China Jiangsu Key Laboratory of Urban and Industrial Safety School of Urban Construction and Safety Engineering Nanjing University of Technology Nanjing 210009 China

Chemical process equipment and the damage phenomenon were categorized. Data were collected and unnecessary overpressure values together with the corresponding damage phenomenon in which the domino effect did not appear were deleted. The entire range of damage probability was divided into three categories according to degree of damage, by two segmentation points of random variables, and the model of damage probability following a uniform distribution in each degree of damage was proposed, in order to establish more detailed and realistic probit models. The influence of the two random separation points on the mean square errors was investigated and the average of the errors was regarded as the criterion for integral accuracy of the created models. The results showed that the mean square errors of different equipment and their average decreased according to the smaller separation point, and decreased initially and then increased with the larger separation point. The prediction model with high reliability was obtained by data fitting to calculate the average of the mean square errors, which reached a minimum when the values of both break points were 0.3363. These probit models of the four equipment categories with lower mean square errors and better consistency between predicted and observed data were proposed after correcting the few and unnecessary observed data used in curve regression and oversimplification in the probability arrangement in a previous study. The threshold value for damage of 33.63% was 19, 37, 26 and 31 kPa for atmospheric, pressurized, elongated and small equipment, respectively.

关键词： Mean square error

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reliability analysis of infinite soil slopes considering spatial variability of soil parameters

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Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical engineering 2013年第10期35卷 1799-1806页

作者： Li, Dian-Qing Qi, Xiao-Hui Zhou, Chuang-Bing Zhang, Li-Min State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan 430072 China Ministry of Edu. Wuhan 430072 China Department of Civil and Environmental Engineering The Hong Kong University of Science and Technology Clear Water Bay Hong Kong Hong Kong

The effect of the variation of soil shear strength parameters with depth on slope stability considering spatial variability of soil parameters has not been studied systematically. A probabilistic method is proposed for infinite slope stability analysis considering the variation of soil shear strength parameters with depth. First, the Karhunen-Loeve expansion is adopted to simulate the random field of spatially varying soils. Second, the effect of spatial variability of soil parameters on failure probability and critical slip surfaces is investigated. Finally, an infinite slope is presented to demonstrate the validity and capacity of the proposed method. The results indicate that the spatial variability of soil shear strength parameters has a significant influence on the failure probability of the infinite soil slope. The failure probability decreases with the increasing correlation length of soil shear strength parameters. For an undrained clay slope, a significant change in the undrained shear strength parameter varying with depth results in a smaller failure probability. Most of the critical slip surfaces will occur at the base of the slope. For a frictional/cohesive slope, the failure probability does not monotonically decrease with the increase of the variation of the soil shear strength parameters with depth. The trend of shear strength varying with depth has a significant influence on the critical slip surfaces. If the trend of shear strength varying with depth is ignored, it is most likely that the critical slip surfaces will occur at the base of the slope.

关键词： Shear strength

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