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再论油气初次运移量计算及其参数选取 被引量:10
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作者 田世澄 《地球科学(中国地质大学学报)》 EI CAS CSCD 北大核心 1990年第1期9-14,共6页
作者于1982年提出了油气初次运移量的计算公式并对几个盆地进行了试算。在本文中,作者进一步讨论了公式中各个量的物理意义,指出流体的排出量应当包括以下几方面的量值:压实作用造成孔隙度减小;埋深增加,流体比容增大;粘土矿物随埋深增... 作者于1982年提出了油气初次运移量的计算公式并对几个盆地进行了试算。在本文中,作者进一步讨论了公式中各个量的物理意义,指出流体的排出量应当包括以下几方面的量值:压实作用造成孔隙度减小;埋深增加,流体比容增大;粘土矿物随埋深增加,发生转化;以及烃形成所导致的体积膨胀。并具体讨论了这些排液量的计算方法,以及在实际计算过程中其它各个物理量的取值和计算方法。 展开更多
关键词 油气 初次 运移量 参数 资源
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科尔沁沙地沙丘水分深层渗漏量和侧向运移量 被引量:9
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作者 曹静 阿拉木萨 张圆浩 《中国沙漠》 CSCD 北大核心 2019年第3期41-47,共7页
沙丘水分的深层渗漏和侧向运移与深层土壤水、地下水及相邻丘间低地的水分状况密切关联。以科尔沁沙地典型流动沙丘迎风坡坡底\,迎风坡坡中、坡顶、背风坡坡中和背风坡坡底监测点为例,采用自制的水分渗漏量及侧向运移量的监测装置,测定... 沙丘水分的深层渗漏和侧向运移与深层土壤水、地下水及相邻丘间低地的水分状况密切关联。以科尔沁沙地典型流动沙丘迎风坡坡底\,迎风坡坡中、坡顶、背风坡坡中和背风坡坡底监测点为例,采用自制的水分渗漏量及侧向运移量的监测装置,测定了科尔沁沙地流动沙丘各坡位入渗到0~100 cm土层雨水沿坡面的侧向运移量及入渗到100 cm以下的深层渗漏量。结果表明:生长季(5-10月)流动沙丘坡顶、迎风坡坡中、背风坡坡中、背风坡坡底处累积深层渗漏量分别为44.46、78.65、61.84、147.6 mm,分别占同期降雨量的17.03%、30.12%、23.68%、56.53%;迎风坡坡中、背风坡坡中、背风坡坡底处的累积侧向运移量分别为32.35、96.47、82.59mm,分别占同期降雨量的12.39%、36.95%、31.63%。迎风坡坡中(P<0.01)和坡顶(P<0.05)的月深层渗漏量与月降雨量均显著正相关;背风坡坡中(P<0.01)和背风坡坡底(P<0.05)的月侧向运移量与降雨量均显著正相关。 展开更多
关键词 流动沙丘 深层渗漏 侧向运移量 降雨
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西伯利亚与印度地块间早白垩世以来南北向缩短量的估算 被引量:2
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作者 李朋武 崔军文 +1 位作者 高锐 李莉 《地球学报》 EI CAS CSCD 北大核心 2003年第2期111-114,共4页
利用古地磁数据 ,对西伯利亚地块、拉萨地块、喜马拉雅地块和印度地块纬度运移量对比表明 ,喜马拉雅地块属于印度地块 ;分隔喜马拉雅和拉萨地块的新特提斯洋盆在早白垩世张开至最大纬度宽度 3 1.9°;早白垩世以来 ,西伯利亚地块和... 利用古地磁数据 ,对西伯利亚地块、拉萨地块、喜马拉雅地块和印度地块纬度运移量对比表明 ,喜马拉雅地块属于印度地块 ;分隔喜马拉雅和拉萨地块的新特提斯洋盆在早白垩世张开至最大纬度宽度 3 1.9°;早白垩世以来 ,西伯利亚地块和印度地块间的纬度缩短量达 5 8.2°。去除新特提斯洋盆最大宽度后 ,西伯利亚和印度地块间的陆壳纬度缩短量达 2 6.3°,大约2 760km。根据柴达木地块和喜马拉雅地块的古地磁数据 ,早白垩世以来 ,柴达木地块和喜马拉雅地块间SN向上地壳缩短了约 5 0 .2°。早白垩世以来 ,南部地块的纬度漂移速率大于北部 ,柴达木地块与其以南喜马拉雅地块间的缩短量大于柴达木地块和西伯利亚间的缩短作用 ,纬度运移的明显差异是导致青藏高原挤压。 展开更多
关键词 早白垩世 南北向缩短 青藏高原 喜马拉雅 纬度运移量 挤压
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运移参数对GCL中污染物运移的影响研究 被引量:1
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作者 何俊 《煤田地质与勘探》 CAS CSCD 北大核心 2005年第6期42-45,共4页
分析了运移参数的变化对GCL中污染物运移的影响。从衬垫底部浓度比、对流和扩散通量、污染物累积运移量等方面,对污染物在GCL中的运移进行了计算。结果表明,减小渗透系数和扩散系数可以有效减缓衬垫底部浓度比的增加速度。渗透系数对对... 分析了运移参数的变化对GCL中污染物运移的影响。从衬垫底部浓度比、对流和扩散通量、污染物累积运移量等方面,对污染物在GCL中的运移进行了计算。结果表明,减小渗透系数和扩散系数可以有效减缓衬垫底部浓度比的增加速度。渗透系数对对流通量的大小、扩散通量的变化速度的影响较大;扩散系数主要影响最大扩散通量。当渗透系数较大时,可以忽略扩散累积运移量,用对流累积运移量代替总累积运移量引起的误差很小。当渗透系数较小时,忽略扩散运移量可能产生较大的误差,尤其是在扩散系数也较大的情况下误差更加明显。 展开更多
关键词 渗透系数 扩散系数 GCL 累积运移量
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石油和天然气运聚效率的主控因素及定量评价 被引量:22
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作者 周海燕 庞雄奇 +1 位作者 姜振学 周杰 《石油勘探与开发》 SCIE EI CAS CSCD 北大核心 2002年第1期14-18,共5页
烃源岩生成的石油和天然气大部分在运聚成藏过程中损失了 ,因此石油和天然气运聚效率主要取决于油气运聚过程中的损耗量的大小。损耗量包括烃源岩残留烃量、储集层滞留烃量、运移流散烃量和构造破坏烃量。天然气的运聚效率远小于石油 ,... 烃源岩生成的石油和天然气大部分在运聚成藏过程中损失了 ,因此石油和天然气运聚效率主要取决于油气运聚过程中的损耗量的大小。损耗量包括烃源岩残留烃量、储集层滞留烃量、运移流散烃量和构造破坏烃量。天然气的运聚效率远小于石油 ,是由于天然气在溶解性、扩散性、吸附性等物理性质方面与石油有差异。通过对塔里木盆地寒武系—下奥陶统及中、上奥陶统烃源岩的模拟计算 ,认为影响石油运聚效率的主要因素是构造破坏作用和储集层滞留作用 ,而影响天然气运聚效率的主控因素是运移过程中的扩散、溶解及构造破坏作用。构造作用同时控制塔里木盆地石油和天然气的运聚效率 ,对正确评价油气资源量有重大意义。图 3表 5参 2 展开更多
关键词 油气运聚效率 烃源岩 残留烃 储集层滞留烃 运移流散烃 评价
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“油气人工运移”技术探索与实践
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作者 焦青琼 韩鑫 +2 位作者 何志辉 李树松 王文涛 《石油化工应用》 CAS 2019年第6期52-57,共6页
南海西部存在较多的规模小、分布分散、储层复杂的低品位边际油气藏,受海上投资成本制约,采用常规开发模式难以经济有效开发。“油气人工运移开发技术”应用压差原理将低品位边际储量通过人工运移通道运移至已开发储层,利用现有生产设... 南海西部存在较多的规模小、分布分散、储层复杂的低品位边际油气藏,受海上投资成本制约,采用常规开发模式难以经济有效开发。“油气人工运移开发技术”应用压差原理将低品位边际储量通过人工运移通道运移至已开发储层,利用现有生产设施可实现间接经济有效的开发。在W-1油田成功投产前,解决了独立油藏合并、井筒油藏耦合、运移量预测与测量三大技术问题,预测人工运移井累积运移气量0.51×10^8m^3,累增油3.63×10^4m^3,提高采收率7.5%,有效盘活了低品位边际油气藏储量。 展开更多
关键词 油气人工运移 独立油藏合并 井筒油藏耦合 运移量 监测
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基于杭州软土的电渗迁移过程试验研究 被引量:7
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作者 陶燕丽 周建 +1 位作者 龚晓南 祝行 《中南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2018年第2期448-453,共6页
为研究电渗迁移过程,进一步揭示电渗机理,基于杭州软土和自制电渗模型箱,分别采用铁和石墨电极开展室内电渗试验,监测重力排水、电渗排水以及电渗前后土壤中多种金属元素含量的变化;监测电流和排水量数据并据此计算电渗运移量。研究结... 为研究电渗迁移过程,进一步揭示电渗机理,基于杭州软土和自制电渗模型箱,分别采用铁和石墨电极开展室内电渗试验,监测重力排水、电渗排水以及电渗前后土壤中多种金属元素含量的变化;监测电流和排水量数据并据此计算电渗运移量。研究结果表明:在电渗排水过程中,钠离子和钾离子质量浓度比重力排水过程中的大得多,镁离子和钙离子质量浓度则比重力排水过程中的小得多,说明电渗法依赖双电层中低阶、小原子量反离子对水分的转移作用,土壤本身物理力学性质对电渗过程的影响主要通过双电层体现。电渗运移量对土壤含水率的敏感性与土壤类型密切相关,而对同一类土壤,其敏感性也可能会随着含水率范围的不同而呈现较大差异。在1.58V/cm的电势梯度下,杭州软土电渗处理后的最终含水率为35%左右,说明对于含水率小于35%的杭州软土,电渗法效果不明显,不推荐采用电渗法进行处理。 展开更多
关键词 杭州软土 重力排水 电渗排水 离子迁移 电渗运移量 含水率
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Effects of multidisciplinary exercise management on patients after percutaneous coronary intervention:A randomized controlled study 被引量:4
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作者 Ya-Jie Shi Yu Liu +2 位作者 Tong-Tong Jiang Hong-Ru Zhang Tie-Ying Shi 《International Journal of Nursing Sciences》 CSCD 2022年第3期286-294,共9页
Objectives To explore the effectiveness of the mobile app-based multidisciplinary exercise management on patients who receive percutaneous coronary intervention(PCI).Methods From January to October 2020,54 patients af... Objectives To explore the effectiveness of the mobile app-based multidisciplinary exercise management on patients who receive percutaneous coronary intervention(PCI).Methods From January to October 2020,54 patients after PCI were randomly assigned to the intervention group(n=27)and the control group(n=27).The intervention group received the mobile app-based multidisciplinary exercise management,whereas the control group received routine care.The patients after PCI began to take intervention one month after the operation,and the intervention lasted for two months.Before and after the intervention,6-Minute Walking Distance was used to evaluate the patient’s exercise tolerance,and the patient’s exercise compliance was evaluated according to the patient’s exercise status recorded by the mobile app.The cognitive questionnaire on knowledge about PCI treatment for Coronary Heart Disease,the Self-efficacy for Chronic Disease Scale and the Perceived Social Support Scale were used to evaluate patients’disease-related cognition,self-efficacy and perception of social support.This study was registered on Clinical Trials.gov with registration number ChiCTR2000028930.Results Totally 51 patients after PCI who completed this study(25 patients in the intervention group and 26 patients in the control group)were included in the analysis.After 2 months of intervention,the exercise compliance of patients in the intervention group was better than that in the control group.And 6-Minute Walking Distance(469.36±57.48 vs.432.81±67.09),and the scores of knowledge of PCI treatment for coronary heart disease(52.64±9.82 vs.42.42±8.54),Self-efficacy for Chronic Disease Scale(42.40±8.04 vs.36.88±7.73)and Perceived Social Support Scale(74.04±5.73 vs.66.69±6.86)in the intervention group were higher than those in the control group with statistical significance(P<0.05).Conclusions The multidisciplinary exercise management based on the mobile app can effectively improve exercise tolerance,exercise compliance,disease-related cognition,self-efficacy,and perception of social support during exercise training for patients after PCI. 展开更多
关键词 Coronary disease EXERCISE Exercise tolerance Mobile applications Percutaneous coronary intervention Self efficacy Social support
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Displacement Trends of Slow-moving Landslides: Classification and Forecasting 被引量:7
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作者 CASCINI Leonardo CALVELLO Michele GRIMALDI Giuseppe Maria 《Journal of Mountain Science》 SCIE CSCD 2014年第3期592-606,共15页
A framework is proposed to characterize and forecast the displacement trends of slow-moving landslides, defined as the reactivation stage of phenomena in rocks or fine-grained soils, with movements localized along one... A framework is proposed to characterize and forecast the displacement trends of slow-moving landslides, defined as the reactivation stage of phenomena in rocks or fine-grained soils, with movements localized along one or several existing shear surfaces. The framework is developed based on a thorough analysis of the scientific literature and with reference to significant reported case studies for which a consistent dataset of continuous displacement measurements is available. Three distinct trends of movement are defined to characterize the kinematic behavior of the active stages of slow-moving landslides in a velocity-time plot: a linear trend-type I, which is appropriate for stationary phenomena; a convex shaped trend-type II, which is associated with rapid increases in pore water pressure due to rainfall, followed by a slow decrease in the groundwater level with time; and a concave shaped trend-type III, which denotes a non-stationary process related to the presence of new boundary conditions such as those associated with the development of a newly formed local slip surface that connects with the main existing slip surface. Within the proposed framework, a model is developed to forecast future displacements for active stages of trend-type II based on displacement measurements at the beginning of the stage. The proposed model is validated by application to two case studies. 展开更多
关键词 Slow-moving landslides Displacements forecast Trends of movement
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Transport simulation of sorptive contaminants considering sediment-associated processes
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作者 李瑞杰 陆莎莎 郑俊 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2012年第4期668-674,共7页
Sediment-associated processes, such as sediment erosion, deposition, and pore water diffusion/advection affect sorptive contaminant transport. By considering these processes, we developed an equation to simulate conta... Sediment-associated processes, such as sediment erosion, deposition, and pore water diffusion/advection affect sorptive contaminant transport. By considering these processes, we developed an equation to simulate contaminant transport. Erosion and deposition processes are considered as erosion and deposition fluxes of sediment, and adsorption-desorption processes of contaminants by sediment are simulated using the Langmuir Equation. Pore water diffusion is calculated based on the contaminant concentration gradient across the sediment-water interface. Pore water advection is estimated using pore water contained in the sediments of erosion flux. The equation is validated to simulate total phosphorus concentrations in Guanhe estuary in the northern Jiangsu, China. The simulated total phosphorus concentrations show better agreement with field observations compared to estimations that do consider sediment-associated processes. 展开更多
关键词 sorptive contaminant SEDIMENT transport equation Guanhe estuary
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Non-capacity transport of non-uniform bed load sediment in alluvial rivers 被引量:7
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作者 CAO Zhi-xian HU Peng +1 位作者 PENDER Gareth LIU Huai-han 《Journal of Mountain Science》 SCIE CSCD 2016年第3期377-396,共20页
Rivers often witness non-uniform bed load sedim ent transport. For a long tim e, non-uniform bed load transport has been assum ed to be at capacity regime determined exclusively by local flow. Yet whether the capacity... Rivers often witness non-uniform bed load sedim ent transport. For a long tim e, non-uniform bed load transport has been assum ed to be at capacity regime determined exclusively by local flow. Yet whether the capacity assumption for non-uniform bed load transport is justified remains poorly understood. Here, the relative time scale of non-uniform bed load transport is evaluated and non-capacity and capacity models are compared for both aggradation and degradation cases with observed data. As characterized by its relative time scale, the adaptation of non-uniform bed load to capacity regime should be fulfilled quickly. However, changes in the flow and sedim ent inputs from upstream or tributaries hinder the adaptation. Also, the adaptation to capacity regime is size dependent, the finer the sediment size the slower the adaptation is, and vice versa. It is shown that the capacity model may entail considerable errors compared to the non-capacity model. For modelling of non-uniform bed load, non-capacity modelling is recommended, in which the temporal and spatial scales required for adaptation are explicitly appreciated. 展开更多
关键词 Fluvial process Sediment transport Bed deformation Non-uniform bed load Capacity transport
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科尔沁沙地沙丘生境单元凋落物运移特征 被引量:8
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作者 王新源 赵学勇 +3 位作者 李玉霖 陈翔舜 王小军 云建英 《中国沙漠》 CSCD 北大核心 2016年第1期167-173,共7页
通过测定科尔沁沙地沙丘生境单元凋落物的运移量,分析了沙丘类型和生境变化对凋落物运移的影响,并探讨了是否可以通过凋落物运移量的变化来判断营养物质的迁移。结果表明:科尔沁沙地沙丘凋落物的运移过程主要发生在非生长季,呈明显的... 通过测定科尔沁沙地沙丘生境单元凋落物的运移量,分析了沙丘类型和生境变化对凋落物运移的影响,并探讨了是否可以通过凋落物运移量的变化来判断营养物质的迁移。结果表明:科尔沁沙地沙丘凋落物的运移过程主要发生在非生长季,呈明显的单峰型季节波动。凋落物运移量在不同沙丘的丘间地、迎风坡、丘顶和背风坡均表现出明显的空间差异性,丘顶的凋落物运移量最大,迎风坡次之,丘间地和背风坡相对较小。凋落物运移量有随距地表高度增加而下降的趋势,距地表高度为0~25cm时,凋落物运移量最大,显著高于25~50、50~75、75~100cm3个高度区间。凋落物运移量与风速在流动沙丘、半固定沙丘和固定沙丘均呈显著的二次曲线正相关,显示风速是影响凋落物运移量动态变化的重要因素。 展开更多
关键词 科尔沁沙地 生境单元 风速 凋落物运移量
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Geometric Phase Gate Based on Both Displacement Operator and Squeezed Operators with a Superconducting Circuit Quantum Electrdynamics
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作者 陈昌永 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第7期91-95,共5页
We give the brief review on the related definition of the geometric phase independent of specific physical system based on the displacement opreator and the sqeezed operator, then show how the displacement operator an... We give the brief review on the related definition of the geometric phase independent of specific physical system based on the displacement opreator and the sqeezed operator, then show how the displacement operator and the squeezed operator can induce the general geometric phase. By means of the displacement operator and the squeezed operator concerning the circuit cavity mode state along a closed path in the phase space, we discuss specifically how to implement a two-qubit geometric phase gate in circuit quantum electrodynamics with both single photon interaction and two-photon interaction between the superconducting qubits and the circuit cavity modes. The experimental feasibility is discussed in detail. 展开更多
关键词 geometric gate circuit quantum electrodynamics sequeezed operator
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A robust system for real-time pedestrian detection and tracking 被引量:2
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作者 李琦 邵春福 赵熠 《Journal of Central South University》 SCIE EI CAS 2014年第4期1643-1653,共11页
A real-time pedestrian detection and tracking system using a single video camera was developed to monitor pedestrians. This system contained six modules: video flow capture, pre-processing, movement detection, shadow ... A real-time pedestrian detection and tracking system using a single video camera was developed to monitor pedestrians. This system contained six modules: video flow capture, pre-processing, movement detection, shadow removal, tracking, and object classification. The Gaussian mixture model was utilized to extract the moving object from an image sequence segmented by the mean-shift technique in the pre-processing module. Shadow removal was used to alleviate the negative impact of the shadow to the detected objects. A model-free method was adopted to identify pedestrians. The maximum and minimum integration methods were developed to integrate multiple cues into the mean-shift algorithm and the initial tracking iteration with the competent integrated probability distribution map for object tracking. A simple but effective algorithm was proposed to handle full occlusion cases. The system was tested using real traffic videos from different sites. The results of the test confirm that the system is reliable and has an overall accuracy of over 85%. 展开更多
关键词 image processing technique pedestrian detection tracking video camera
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Analysis of Systematic Error Influences on Accuracy of Airborne Laser Scanning Altimetry
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作者 ZHANGXiaohong LIUJingnan 《Geo-Spatial Information Science》 2004年第3期218-224,共7页
The error sources related to the laser rangefinder, GPS and INS are analyzed in details. Several coordinates systems used in airborne laser scanning are set up, and then the basic formula of system is given. This pape... The error sources related to the laser rangefinder, GPS and INS are analyzed in details. Several coordinates systems used in airborne laser scanning are set up, and then the basic formula of system is given. This paper emphasizes on discussing the kinematic offset correction between GPS antenna phase center and laser fired point. And kinematic time delay influence on laser footprint position, the ranging errors, positioning errors, attitude errors and integration errors of the system are also explored. Finally, the result shows that the kinematic time delay can be neglected as compared with other error sources. The accuracy of the coordinates is not only influenced by the amplitude of the error, but also controlled by the operation parameters such as flight height, scanning angle amplitude and attitude magnitude of the platform. 展开更多
关键词 airborne laser scanning altimetry kinematic offset corrections kinematictime delays error analysis imitation calculation
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Hole mobility enhancement in uniaxial stressed Ge dependence on stress and transport direction 被引量:1
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作者 MA JianLi FU ZhiFen +1 位作者 LIU Peng ZHANG HeMing 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2014年第10期1860-1865,共6页
Utilizing a six-band k.p valence band calculations that considered a strained perturbation Hamiltonian, uniaxial stress-induced valence band structure parameters for Ge such as band edge energy shift, split, and effec... Utilizing a six-band k.p valence band calculations that considered a strained perturbation Hamiltonian, uniaxial stress-induced valence band structure parameters for Ge such as band edge energy shift, split, and effective mass were quantitatively evaluated. Based on these valence band parameters, the dependence of hole mobility on uniaxial stress(direction, type, and magnitude) and hole transport direction was theoretical studied. The results show that the hole mobility had a strong dependence on the transport direction and uniaxial stress. The hole mobility enhancement can be found for all transport directions and uniaxial stess configurations, and the hole transport along the [110] direction under the uniaxial [110] compressive stress had the highest mobility compared to other transport directions and stress configurations. 展开更多
关键词 Ge uniaxial stress valence band structure hole mobility
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Unsupervised Spatio-Temporal Segmentation for Extracting Moving Objects in Video Sequences 被引量:1
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作者 李仁杰 余松煜 王向文 《Journal of Shanghai Jiaotong university(Science)》 EI 2009年第2期154-161,共8页
Extraction of moving objects is an important and fundamental research topic for many video applications. This paper addresses an unsupervised spatio-temporal segmentation scheme to extract moving objects from video se... Extraction of moving objects is an important and fundamental research topic for many video applications. This paper addresses an unsupervised spatio-temporal segmentation scheme to extract moving objects from video sequences.The temporal segmentation localizes moving objects by comparing the motion vector of each block in each frame with the corresponding global motion vector estimated by an outlier rejection(OR) based method.Furthermore,the temporal compensation utilizing the temporal coherence of moving objects is considered in the temporal segmentation to solve the temporarily stopping problem.The detected moving regions usually have discontinuous boundaries and some holes.These regions are then compensated in the spatial domain. In the spatial segmentation,the watershed algorithm considering the global information improves the accuracy of segmentation in the spatial domain.The modified mean filter is presented to suppress some minima.By using a fusion module,moving objects are extracted.Experiments on various sequences have successfully demonstrated the validity of the proposed scheme. 展开更多
关键词 SEGMENTATION SPATIO-TEMPORAL region growing outlier rejection WATERSHED
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Excess heat capacity in glass-forming liquid systems containing molecules 被引量:1
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作者 KE HaiBo WEN Ping WANG WeiHua 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第6期1090-1095,共6页
Excess heat capacities at glass transition temperature in two types of glass-forming systems of [xNaNO3(1x)KNO3]60·[Ca(NO3)2]40(0x1) and Ca(NO3)2yH2O(4y13) are studied.In the former system,with the replacement of... Excess heat capacities at glass transition temperature in two types of glass-forming systems of [xNaNO3(1x)KNO3]60·[Ca(NO3)2]40(0x1) and Ca(NO3)2yH2O(4y13) are studied.In the former system,with the replacement of K + cation with Na + cation,the excess heat capacity is around 65.1 J mol-1·K-1,while the excess increases by 38.9 J mol-1·K-1 upon one molar H2O content in latter system.A quantitative description to the excess heat capacity is built up with the thermal effects of atomic and molecular translational motion in liquids.The results might offer a further understanding to the glass transition. 展开更多
关键词 glass-forming liquid excess heat capacity the glass transition
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OCCUPATION TIMES OF BALLS BY BROWNIAN MOTION WITH DRIFT
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作者 尹传存 赵崇诺 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2001年第1期47-56,共10页
Let X = {Xt,t >=0} be a d-dimensional (d>= 2) standard Brownian motion with drift c started at a fixed x, and BR = {x E Rd: |x| < R}, the ball centered at 0 with radius R. Consider the distributions of TR(t) ... Let X = {Xt,t >=0} be a d-dimensional (d>= 2) standard Brownian motion with drift c started at a fixed x, and BR = {x E Rd: |x| < R}, the ball centered at 0 with radius R. Consider the distributions of TR(t) and TR(∞), where TR(t) denotes the time spent by X in BR up to time t and TR(∞) the total time of X spent in BR. Explicit formulas for the Laplace transform of TR(∞) and the double Laplace transform of TR(t) are obtained. 展开更多
关键词 Brownian motion with drift Occupation time BALL Laplace transform
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Drift perturbation of subordinate Brownian motions with Gaussian component
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作者 CHEN Zhen-Qing DOU XiaoMan 《Science China Mathematics》 SCIE CSCD 2016年第2期239-260,共22页
Let d ≥ 1 and Z be a subordinate Brownian motion on R^d with infinitesimal generator ? + ψ(?),where ψ is the Laplace exponent of a one-dimensional non-decreasing L′evy process(called subordinator). We establish th... Let d ≥ 1 and Z be a subordinate Brownian motion on R^d with infinitesimal generator ? + ψ(?),where ψ is the Laplace exponent of a one-dimensional non-decreasing L′evy process(called subordinator). We establish the existence and uniqueness of fundamental solution(also called heat kernel) pb(t, x, y) for non-local operator L^b= ? + ψ(?) + b ?, where Rb is an Rd-valued function in Kato class K_(d,1). We show that p^b(t, x, y)is jointly continuous and derive its sharp two-sided estimates. The kernel pb(t, x, y) determines a conservative Feller process X. We further show that the law of X is the unique solution of the martingale problem for(L^b, C_c~∞(R^d)) and X is a weak solution of Xt = X0+ Zt + integral from n=0 to t(b(Xs)ds, t ≥ 0).Moreover, we prove that the above stochastic differential equation has a unique weak solution. 展开更多
关键词 subordinate Brownian motion heat kernel Kato class gradient perturbation Feller process L^vysystem martingale problem stochastic differential equation
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