随着山区高速公路建设的迅速推进,弃渣场的稳定性及潜在失稳灾害评估日益受到重视。具有巨大能量的滑坡体,可能会冲击破坏沿途的结构物进而威胁生命财产安全。充分发挥利用物质点法(material point method,MPM)可以对连续介质大变形过...随着山区高速公路建设的迅速推进,弃渣场的稳定性及潜在失稳灾害评估日益受到重视。具有巨大能量的滑坡体,可能会冲击破坏沿途的结构物进而威胁生命财产安全。充分发挥利用物质点法(material point method,MPM)可以对连续介质大变形过程模拟和离散元法(digital elevation model,DEM)能够精准的接触判断优势,MPM-DEM耦合算法可有效解决滑坡体与复杂地形、沿线结构物之间的相互作用问题。文章基于GPU并行高性能计算软件CoSim中的MPM-DEM耦合算法,实现了对弃渣场边坡稳定性、潜在失稳灾害的动力学分析。研究首先以散粒体冲击结构物的算例,验证了该算法的合理性与准确性;在此基础上,以云南某高速公路弃渣场为研究案例,进一步计算其稳定性系数,并预测潜在失稳灾害的影响范围与危害程度。结果表明,该弃渣场边坡目前处于稳定状态;若发生失稳,滑坡体将对下游高速公路桥桩产生巨大冲击力。该耦合算法在弃渣场边坡稳定性与失稳灾害动力学分析中具备显著优势,能够实现边坡“稳定性→大变形→流动→堆积”的全过程分析。展开更多
Ground anchor drilling is a promising technology for investigating the mechanical properties and environmental variability of lunar regolith in low-gravity environments,with minimal demands for reactive cutting.This s...Ground anchor drilling is a promising technology for investigating the mechanical properties and environmental variability of lunar regolith in low-gravity environments,with minimal demands for reactive cutting.This study explores the interaction behavior during ground anchor drilling of lunar regolith by employing a coupled approach that integrates the Material Point Method(MPM)and the ContinuouseDiscontinuous Element Method(CDEM),considering the interactions among numerous particles and blocks.The numerical parameters are calibrated based on experimental penetration resistance data of lunar regolith simulant.The numerical approach effectively captures key mechanical properties of the simulant,such as particle flow and scattering patterns,anchor penetration effects,and disturbance-related ultimate bearing characteristics.Additionally,this study examines the influence of inter-particle friction and compactness on penetration resistance.By combining the Golden Section Search Method(GSSM)with ground anchor drilling simulations,an inverse analysis model for penetration resistance is developed,allowing for the determination of mechanical parameters of the lunar regolith simulant.The feasibility of this parameter inversion method is verified,providing valuable insights for engineering applications in lunar exploration and construction.展开更多
基于区域和统计的SAR分割方法,提出一种结合Voronoi划分技术、最大期望值EM(Expectation Maximization)和最大边缘概率MPM(Maximization of the Posterior Marginal)算法的多视SAR图像分割方法。首先利用Voronoi划分将图像域划分成不同...基于区域和统计的SAR分割方法,提出一种结合Voronoi划分技术、最大期望值EM(Expectation Maximization)和最大边缘概率MPM(Maximization of the Posterior Marginal)算法的多视SAR图像分割方法。首先利用Voronoi划分将图像域划分成不同的子区域,而每个子区域可以被看成待分割同质区域的一个组成部分,并假设每个子区域内的像素满足同一独立的Gamma分布,从而建立多视SAR图像模型,并在贝叶斯理论架构下建立图像分割模型,然后结合EM/MPM算法进行图像分割和模型参数估计。该方法将基于像元的马尔可夫随机场(Markov Random Field,MRF)模型扩展到基于区域的MRF模型,并且能同时有效地获取模型参数估计和基于区域的SAR图像最优分割。采用本文算法,分别对RADARSAT-Ⅰ/ⅡSAR强度图像和合成SAR强度图像进行了分割实验,定性和定量的测试结果验证了本文方法的有效性、可靠性和准确性。展开更多
[ Objective] The experiment aimed to clone Paramyosin/mini-Paramyosin （PM/mPM） gene to analyze the relations between it and moving behaviors. [Method] PCR method and RACE technology were used to obtain whole cDNA of...[ Objective] The experiment aimed to clone Paramyosin/mini-Paramyosin （PM/mPM） gene to analyze the relations between it and moving behaviors. [Method] PCR method and RACE technology were used to obtain whole cDNA of PM and some cDNA of mPM of Bombyx moil. By comparing wgs of Bombyx mori, the genomic sequence of PM/mPM of Bombyx mori was obtained, and, their genome structure was determined. [ Result] PM/mPM genes consisted of 17 exons and 16 intrens. By the use of selective promoters, The gene sequence encoded PM and mPM, while PM and mPM shared the last 6 exons. The cluster analysis between PM of Bombyx mori and PM of other invertebrate animals demonstrated that the relation between Bombyx mori and Bombyx mandarina was closest and the relation between Bombyx mori and Drosophila melanogaster was farthest in Insecta. [ Conclusion] There was no point mutation which could influence flight in amino acid sequence of PM of Bombyx mori and Bombyx mandarina, so the difference of flight capacity of Bombyx mori and Bombyx mandarina might be regulated by other mechanism.展开更多
文摘随着山区高速公路建设的迅速推进,弃渣场的稳定性及潜在失稳灾害评估日益受到重视。具有巨大能量的滑坡体,可能会冲击破坏沿途的结构物进而威胁生命财产安全。充分发挥利用物质点法(material point method,MPM)可以对连续介质大变形过程模拟和离散元法(digital elevation model,DEM)能够精准的接触判断优势,MPM-DEM耦合算法可有效解决滑坡体与复杂地形、沿线结构物之间的相互作用问题。文章基于GPU并行高性能计算软件CoSim中的MPM-DEM耦合算法,实现了对弃渣场边坡稳定性、潜在失稳灾害的动力学分析。研究首先以散粒体冲击结构物的算例,验证了该算法的合理性与准确性;在此基础上,以云南某高速公路弃渣场为研究案例,进一步计算其稳定性系数,并预测潜在失稳灾害的影响范围与危害程度。结果表明,该弃渣场边坡目前处于稳定状态;若发生失稳,滑坡体将对下游高速公路桥桩产生巨大冲击力。该耦合算法在弃渣场边坡稳定性与失稳灾害动力学分析中具备显著优势,能够实现边坡“稳定性→大变形→流动→堆积”的全过程分析。
基金financial support from the National Natural Science Foundation of China(Grant Nos.52178324,12102059,and 12472207).
文摘Ground anchor drilling is a promising technology for investigating the mechanical properties and environmental variability of lunar regolith in low-gravity environments,with minimal demands for reactive cutting.This study explores the interaction behavior during ground anchor drilling of lunar regolith by employing a coupled approach that integrates the Material Point Method(MPM)and the ContinuouseDiscontinuous Element Method(CDEM),considering the interactions among numerous particles and blocks.The numerical parameters are calibrated based on experimental penetration resistance data of lunar regolith simulant.The numerical approach effectively captures key mechanical properties of the simulant,such as particle flow and scattering patterns,anchor penetration effects,and disturbance-related ultimate bearing characteristics.Additionally,this study examines the influence of inter-particle friction and compactness on penetration resistance.By combining the Golden Section Search Method(GSSM)with ground anchor drilling simulations,an inverse analysis model for penetration resistance is developed,allowing for the determination of mechanical parameters of the lunar regolith simulant.The feasibility of this parameter inversion method is verified,providing valuable insights for engineering applications in lunar exploration and construction.
文摘基于区域和统计的SAR分割方法,提出一种结合Voronoi划分技术、最大期望值EM(Expectation Maximization)和最大边缘概率MPM(Maximization of the Posterior Marginal)算法的多视SAR图像分割方法。首先利用Voronoi划分将图像域划分成不同的子区域,而每个子区域可以被看成待分割同质区域的一个组成部分,并假设每个子区域内的像素满足同一独立的Gamma分布,从而建立多视SAR图像模型,并在贝叶斯理论架构下建立图像分割模型,然后结合EM/MPM算法进行图像分割和模型参数估计。该方法将基于像元的马尔可夫随机场(Markov Random Field,MRF)模型扩展到基于区域的MRF模型,并且能同时有效地获取模型参数估计和基于区域的SAR图像最优分割。采用本文算法,分别对RADARSAT-Ⅰ/ⅡSAR强度图像和合成SAR强度图像进行了分割实验,定性和定量的测试结果验证了本文方法的有效性、可靠性和准确性。
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2006AA10A118)~~
文摘[ Objective] The experiment aimed to clone Paramyosin/mini-Paramyosin （PM/mPM） gene to analyze the relations between it and moving behaviors. [Method] PCR method and RACE technology were used to obtain whole cDNA of PM and some cDNA of mPM of Bombyx moil. By comparing wgs of Bombyx mori, the genomic sequence of PM/mPM of Bombyx mori was obtained, and, their genome structure was determined. [ Result] PM/mPM genes consisted of 17 exons and 16 intrens. By the use of selective promoters, The gene sequence encoded PM and mPM, while PM and mPM shared the last 6 exons. The cluster analysis between PM of Bombyx mori and PM of other invertebrate animals demonstrated that the relation between Bombyx mori and Bombyx mandarina was closest and the relation between Bombyx mori and Drosophila melanogaster was farthest in Insecta. [ Conclusion] There was no point mutation which could influence flight in amino acid sequence of PM of Bombyx mori and Bombyx mandarina, so the difference of flight capacity of Bombyx mori and Bombyx mandarina might be regulated by other mechanism.
