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基于GIS的栅格化坡面径流路径模拟与LS值计算 被引量:12
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作者 吴东亮 刘鹏举 +2 位作者 唐小明 朱清科 朱金兆 《北京林业大学学报》 EI CAS CSCD 北大核心 2001年第5期10-14,共5页
该研究旨在研制建立适合我国黄土区以小流域为单元、基于GIS栅格化的坡面径流路径及土壤侵蚀强度空间分异分析模拟模型 .以ViewGIS为平台 ,将流域图经栅格化处理和建立基于栅格化处理的关系型数据库 ,利用D8方法和DEMON方法 ,分析模拟... 该研究旨在研制建立适合我国黄土区以小流域为单元、基于GIS栅格化的坡面径流路径及土壤侵蚀强度空间分异分析模拟模型 .以ViewGIS为平台 ,将流域图经栅格化处理和建立基于栅格化处理的关系型数据库 ,利用D8方法和DEMON方法 ,分析模拟径流路径 ;开发出了适于分析模拟黄土区小流域土壤侵蚀强度空间分布的模块 ,以小流域为单元对坡面径流路径进行了模拟 ,并模拟计算了通用水土流失方程的地形因子LS值在该流域坡面的分布 ,最后将计算结果存放于关系型数据库中 .该研究深入ViewGIS内核 ,在开发DEM径流分析、土壤侵蚀等功能的基础上 ,实现了对整个流域径流路径及土壤侵蚀地形地貌分异规律的计算机分析模拟与成图 。 展开更多
关键词 GIS DEM 栅格化 坡面径流模拟 ls值计算 流域 土壤侵蚀
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蒙古栎伴生种及邻体物种多样性的研究 被引量:11
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作者 于顺利 马克平 +1 位作者 刘灿然 陈灵芝 《应用生态学报》 CAS CSCD 2002年第3期271-274,共4页
采用点样地法对四个地点蒙古栎树种的邻体多样性进行了研究 ,结果表明 ,随着调查样点数的增加 ,蒙古栎邻体的物种丰富度和Shannon Wiener(H′)物种多样性指数逐渐增加 ,最后趋于一固定值 .用物种共同出现百分率测定了蒙古栎与其伴生种... 采用点样地法对四个地点蒙古栎树种的邻体多样性进行了研究 ,结果表明 ,随着调查样点数的增加 ,蒙古栎邻体的物种丰富度和Shannon Wiener(H′)物种多样性指数逐渐增加 ,最后趋于一固定值 .用物种共同出现百分率测定了蒙古栎与其伴生种的种间联结值 (PC值 ) ,并引入LS值来测定单株蒙古栎相邻物种的平均个体数目 ,结果发现 ,不同地点蒙古栎邻体多样性不同 ,其相邻乔木和灌木种类也有较大差异 ,联结系数各有高低 ,比较PC值的大小 ,得出了蒙古栎的主要伴生乔木和主要伴生灌木物种 (结构和组成 ) .物种 (乔木和灌木 )与蒙古栎伴生的原因主要是相似的环境需求和互惠互利 。 展开更多
关键词 蒙古栎 种间联结系数 PC 邻体多样性 ls值 伴生种
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滇东北山区坡耕地土壤侵蚀的地形因子 被引量:43
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作者 杨子生 《山地学报》 CSCD 1999年第A05期16-18,共3页
通过在滇东北山区坡耕地上设置18个不同坡度和坡长的试验小区,并进行连续3年实测,得到本区域土壤侵蚀地形因子(LS)的定量关系式,据此求得滇东北山区坡耕地土壤侵蚀的坡面地形效应(LS值)表。
关键词 坡耕地 壤侵蚀 地形因子 ls值 试验小区
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澳大利亚农药残留合格率高
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作者 武丽辉 《农药科学与管理》 CAS 2012年第5期14-14,共1页
据全国农药残留调查(NRS)显示,2011年澳大利亚农药残留合格率高,99%以上的粮食样本在法定残留量之内,其中5 220个谷物样本中99.4%在最大残留限量(MRLs值)以内,898个园艺产品样本中99.8%合格。
关键词 农药残留 澳大利亚 合格率 最大残留限量 园艺产品 残留量 ls值 粮食
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Optimizing crashworthiness design of square honeycomb structure 被引量:4
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作者 李萌 邓宗全 +2 位作者 郭宏伟 刘荣强 丁北辰 《Journal of Central South University》 SCIE EI CAS 2014年第3期912-919,共8页
To provide theoretical basis for square honeycombs used as crashworthy structures, energy-absorption properties of metal square honeycombs and the size optimization were performed. Specific energy absorption(SEA) was ... To provide theoretical basis for square honeycombs used as crashworthy structures, energy-absorption properties of metal square honeycombs and the size optimization were performed. Specific energy absorption(SEA) was defined as the energy absorbed by the honeycomb structure per unit volume. This parameter was often used for determining the crashworthiness of thin-walled structures. In order to find the most optimized metal square honeycomb structure with the maximum SEA and the lowest peak stress, the cell length and the foil thickness of the metal honeycombs were optimized, with a low peak stress and a high SEA set as the two primary objectives. The pre-processing software Patran was used to build FE models, and the explicit solver LS-DYNA was employed to perform the crashworthiness analyses. The results show that the square honeycomb exhibits good energy absorption performance in some cases. The geometry is effective using 16.8% less buffer structure volume than the hexagonal honeycombs with a peak stress limitation of 1.21 MPa. 展开更多
关键词 CRASHWORTHINESS square honeycomb response surface methodology numerical simulation multi-objective optimization
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Collision Analysis of the Spar Upper Module Docking
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作者 Yan Liu Liping Sun Chunlin Wu Guo Wei 《Journal of Marine Science and Application》 2014年第2期193-199,共7页
In order to assess the possible collision effect, a numerical simulation for the upper module and spar platlbrm docking at the speed of 0.2 m/s was conducted by using the software ANSYS/LS-DYNA, and the time history o... In order to assess the possible collision effect, a numerical simulation for the upper module and spar platlbrm docking at the speed of 0.2 m/s was conducted by using the software ANSYS/LS-DYNA, and the time history of the collision force, energy absorption and structural defonamtion during the collision was described. The purpose was to ensure that the platlbrm was safely put into operation. Furthermore, this paper analyzes different initial velocities and angles on the Von Mises stress and collision resultant force during the docking collision. The results of this paper showed that the docking could be conducted with higher security. The data in this paper can provide useful references for the determination of the upper module's offshore hoisting scheme and practical construction by contrasting the numerical simulation results of the parameters on the docking collision. 展开更多
关键词 spar upper module DOCKING offshore lifking collisionanalysis: spar plalIbrm- simulation analysis
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Numerical analysis on the shoot resistance of heat treated light weight B-grade bulletproof steel plates 被引量:1
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作者 Ma Mingtu Zhang Jingwen Zhang Junping 《Engineering Sciences》 EI 2014年第5期14-20,共7页
Bulletproof steel plates are widely used for the safety of special vehicles.This paper mainly researches on the shoot resistance of heat treated light weight B-grade bulletproof steel plates through numerical analysis... Bulletproof steel plates are widely used for the safety of special vehicles.This paper mainly researches on the shoot resistance of heat treated light weight B-grade bulletproof steel plates through numerical analysis.Based on the flow behavior of bulletproof steel plates and bullet at various high strain rates,finite element(FE) model has been set up using ANSYS/LS-DYNA software.The simulation results are compared with the shooting results,which show a good consistency and a high reliability.Therefore,the simulation results are efficient approaches and strategies to decide and select the mechanical property and thickness of bulletproof steel plates,saving a lot of work and the cost of experiments. 展开更多
关键词 bulletproof steel plates FE method shooting test
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Numerical simulation of hot stamping of side impact beam 被引量:4
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作者 Guo Yihui Ma Mingtu +4 位作者 Fang Gang Song Leifeng Liu Qiang Wang Xiaona Zhou Dianwu 《Engineering Sciences》 EI 2012年第6期62-66,共5页
Ls-DYNA software is adopted to conduct research of numerical simulation on hot stamping of side impact beam to calculate the temperature field distribution, stress field distribution, forming limit diagram (FLD) fig... Ls-DYNA software is adopted to conduct research of numerical simulation on hot stamping of side impact beam to calculate the temperature field distribution, stress field distribution, forming limit diagram (FLD) figure, etc. in the course of hot stamping so as to predict and analyze the formability of parts. ProCAST software is employed to conduct research of numerical simulation on solid quenching course concerning hot stamping to calculate temperature field distri- bution of tools and component of muhiple stamping cycles. The results obtained from numerical simulation can provide significant reference value to hot stamping part design, formability predication and tools cooling system design. 展开更多
关键词 hot stamping numerical simulation FLD temperature field
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Numerical simulation of blasting effect with divided charge structure 被引量:1
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作者 Hu Tao Li Xianglong +1 位作者 Guan Si He Lihua 《Engineering Sciences》 EI 2014年第6期39-45,共7页
This paper numerically simulates the stress development and generates a three-dimensional model of the medium-length hole blasting in infinite rock mass for continuous charge and divided charge in blasting by using th... This paper numerically simulates the stress development and generates a three-dimensional model of the medium-length hole blasting in infinite rock mass for continuous charge and divided charge in blasting by using the large-scale nonlinear dynamic analysis software LS-DYNA and the elastic-plastic model ~*MAT_PLASTIC_KINEMATIC and JWO-EOS.The differences of the decreasing rate in Von Mises effective stress of blasting,element effective stress peak of free surface,bore wall stress and acceleration are investigated.It is shown that divided charge could greatly improve the blasting effect by engineering blasting practice. 展开更多
关键词 medium-length hole bench blasting divided charge ANSYS/ls-DYNA numerical simulation
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实时剪切波弹性成像技术检测肝脏硬度与血浆脑钠肽浓度变化在慢性心力衰竭中的相关性分析
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作者 舒畅 徐进宇 《中文科技期刊数据库(全文版)医药卫生》 2023年第7期0023-0026,共4页
应用实时剪切波弹性成像测量慢性心力衰竭患者的肝脏硬度(LS),探讨心力衰竭患者NT-proBNP和LS的相关性。方法 根据心功能分级分为四组,对每位患者进行肝脏弹性成像技术检查及血浆NT-proBNP测定,比较分析治疗前后各组的NT-proBNP和LS的... 应用实时剪切波弹性成像测量慢性心力衰竭患者的肝脏硬度(LS),探讨心力衰竭患者NT-proBNP和LS的相关性。方法 根据心功能分级分为四组,对每位患者进行肝脏弹性成像技术检查及血浆NT-proBNP测定,比较分析治疗前后各组的NT-proBNP和LS的差异。结果 治疗前后各相邻两组组间血浆NT-proBNP和LS的差异具有统计学意义(P<0.05),患者血浆NT-proBNP和LS存在显著正相关(r=0.788,P<0.001)。结论 肝脏弹性值能够反映慢性心力衰竭患者病情的严重程度,可作为评价心力衰竭患者治疗及预后的非侵入性检查方法。 展开更多
关键词 心力衰竭 实时剪切波弹性成像技术SWE 血浆NT-PROBNP 肝脏弹性硬度ls
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Study on dynamic response of multi-body structure under explosive driving 被引量:5
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作者 ZHAO YuZhe MA TianBao +1 位作者 LI Jian NING JianGuo 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2016年第9期1360-1369,共10页
In this study, a complex multi-body structure was proposed, and the mechanism for the dynamic response of the structure under explosive driving was investigated by using the Lagrange equations of the second kind. An i... In this study, a complex multi-body structure was proposed, and the mechanism for the dynamic response of the structure under explosive driving was investigated by using the Lagrange equations of the second kind. An initial value subject to explosion loading was analyzed to develop the theoretical model of the dynamic response, and the centroid trajectory of three different structural shapes was solved. To verify the accuracy of the theoretical model, numerical simulation via finite element analysis within LS-DYNA and a dynamic experiment were conducted, and the consistent dynamic response process of the multi-body structure was obtained. In addition, the dynamic response time of the multi-body structure under different explosion loading conditions was calculated by the theoretical model, numerical simulation, and experimental investigation. It was found that the increased opening charge mass reduces the dynamic response time. 展开更多
关键词 explosive driving multi-body structure dynamic model numerical simulation experimental investigation
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