检索结果-南通市图书馆

The collision experiment between rolling stones of different shapes and protective cushion in open-pit mines

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2021年第5期18卷 1391-1403页

作者： Zhu Chun HE Man-chao KARAKUS Murat zhang xiao-hu GUO Zhen School of Earth Sciences and Engineering Hohai UniversityNanjing 210098China Engineering Research Center of Development and Management for Low to Ultra-Low Permeability Oil&Gas Reservoirs in West China Ministry of EducationXi'an Shiyou UniversityXi'an 710021China State Key Laboratory for Geomechanics&Deep Underground Engineering Beijing 100083China School of Civil Environmental and Mining EngineeringThe University of AdelaideAdelaide SA 5005Australia College of Civil Engineering Tongji UniversityShanghai 200092China

Though gravel cushions are used worldwide in open-pit mines and railway slopes to control the impact of rolling stones,no universal technical standards have been put in place to guide engineers in their correct design,and few laboratory test results are available with which to characterize collisions between rolling stones and a gravel *** carried out a large number of experiments in which rolling stones made of the same material but differently shaped were dropped from various heights onto cushions with various particle sizes and *** investigated the characteristics of the resulting collisions,and the relationships between coefficients of restitution(CORs)of blocks with different shape and release height H,cushion thickness h and particle diameter d are obtained through linear fitting *** testing reveals the relative influence of block shape,release height,and the particle size and thickness of the cushion on the collision characteristics,which can assist engineers in designing a gravel cushion suitable to the distribution and weathering characteristics of rolling stones in a specific area.

关键词： Coefficient of restitution(COR) Collision characteristics Gravel cushion Rolling stone shape

Quantifying the spatial variation in the potential productivity and yield gap of winter wheat in China

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2017年第4期16卷 845-857页

作者： zhang Shi-yuan zhang xiao-hu QIU xiao-lei TANG Liang Zhu Yan CAO Wei-xing LIU Lei-lei National Engineering and Technology Center for Information Agriculture Jiangsu Key Laboratory for Information AgricultureJiangsu Collaborative Innovation Center for Modern Crop ProductionNanjing Agricultural University Nanjing 210095 P.R. China

Despite the improvement in cultivar characters and management practices, large gaps between the attainable and potential yields still exist in winter wheat of China. Quantifying the crop potential yield is essential for estimating the food production capacity and improving agricultural policies to ensure food security. Gradually descending models and geographic infor- mation system （GIS） technology were employed to characterize the spatial variability of potential yields and yield gaps in winter wheat across the main production region of China. The results showed that during 2000-2010, the average potential yield limited by thermal resource （YGT） was 23.2 Mg ha-1, with larger value in the northern area relative to the southern area. The potential yield limited by the water supply （YGw） generally decreased from north to south, with an average value of 1.9 Mg ha-1 across the entire study region. The highest YGw in the north sub-region （NS） implied that the irrigation and drainage conditions in this sub-region must be improved. The averaged yield loss of winter wheat from nutrient deficiency （YGH） varied between 2.1 and 3.1 Mg ha-1 in the study area, which was greater than the yield loss caused by water limitation. The potential decrease in yield from photo-thermal-water-nutrient-limited production to actual yield （YGo） was over 6.0 Mg ha-1, ranging from 4.9 to 8.3 Mg ha^-1 across the entire study region, and it was more obvious in the southern area than in the northern area. These findings suggest that across the main winter wheat production region, the highest yield gap was induced by thermal resources, followed by other factors, such as the level of farming technology, social policy and economic feasibility. Furthermore, there are opportunities to narrow the yield gaps by making full use of climatic resources and developing a reasonable production plan for winter wheat crops. Thus, meeting the challenges of food security and sustainability in the coming decades is p

关键词： spatial variation potential productivity yield gap winter wheat China

Land use structural optimization of Lilin based on GMOP-ESV

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2011年第S3期21卷 738-742页

作者： zhang He-bing, zhang xiao-hu School of Surveying & Land Information Engineering, Henan Polytechnic University, Jiaozuo 454000, China School of Surveying & Land Information Engineering Henan Polytechnic University Jiaozuo 454000 China

Land use structural optimization is an effective approach to realize land sustainable utilization and allocate limited land resource rationally. Grey multiple objectives programming (GMOP) model based on China terrestrial ecosystem service value was constructed and applied to Lilin town. The result shows that GMOP model has more practical applicability and takes ecologic, social and comprehensive benefit into consideration. There are three programs after optimization. Program Ⅰ is comprehensive improvement and constructing ecological economy type, program Ⅱ is gross cultivated land dynamic balance type and program Ⅲ is compromise type. There are still problems in programs Ⅱ and Ⅲ, such as distribution in disorder, land left unused or abandoned. Based on the benefits above, Program Ⅰ>Program Ⅲ> Program Ⅱ. Program Ⅰ is the optimal case. Its comprehensive benefit is 8.43208×107 RMB yuan/a.

关键词： land use structure optimization grey multiple objective programming ecosystem service value Lilin town

Accurate mirror-based camera pose estimation with explicit geometric meanings

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2014年第12期57卷 2504-2513页

作者： LI Xin LONG Gu Can GUO Peng Yu LIU Jin Bo zhang xiao hu YU Qi Feng College of Aerospace Science and Engineering National University of Defense Technology hunan Key Laboratory of Videometrics and Vision Navigation

An accurate closed form solution is proposed to estimate camera pose by several mirrored reference object images acquired via a planar mirror under different unknown poses. Compared with state-of-the-art methods, our method is more accurate when there are more than three images and has explicit geometric meanings. This method also properly handles cases in which some of the mirror poses are parallel. The central idea is to minimize an error metric based on all reflections of rotation, which enables the camera rotation to be estimated directly by SVD of sum of mirrored camera rotations. After that, the camera translation is computed by solving a large system of linear equations to minimize object space collinearity error. Both synthesized data and real data experiments show the advantages of our approach.

关键词： pose estimation planar mirror reflection geometric meaning SVD

Numerical simulation on the impact characteristics between rockfalls of different shapes and gravel cushions

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2023年第9期20卷 2731-2743页

作者： Zhu Chun XU Jia-jun WANG Ya-jun HE Man-chao CUI Sheng-hua zhang xiao-hu TAO Zhi-gang School of Earth Sciences and Engineering Hohai UniversityNanjing 210098China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China State Key Laboratory for Geomechanics&Deep Underground Engineering China University of Mining and TechnologyBeijing 100083China School of Civil Engineering Guizhou University of Engineering ScienceBijie 551700China

The shape of rockfalls significantly affects the performance of the impact cushion,which is manifested by the difference in the impact force and the penetration depth of the rockfall during the *** this study,we built the collision numerical model between rockfalls and cushions based on the results from previous studies,and simulated the collision process of rockfalls with four different shapes(cylindrical,cuboid,spherical,and cubic)and different *** parameters when rockfalls impact cushions are calculated,including the maximum impact forces on the surface and bottom of the cushions and the maximum penetration depth of the *** results showed that the maximum impact force on the surface and the bottom of the cushions varies with the rockfall *** maximum impact force on the cushion surface caused by cylindrical rockfall is the smallest,followed by the cuboid rockfall,the cube rockfall,and the spherical *** maximum impact force at the cushion bottom also follows this ***,the penetration depth of cuboid rockfall is the smallest,followed by the cylindrical rockfall,the cubic rockfall,and the spherical *** results of this study provide more extensive theoretical support for rockfall disaster prevention using gravel cushions.

关键词： Gravel cushion Impact force Penetration depth Rockfall shape Numerical simulation

Aspergillus pneumonia in renal transplant recipients

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2008年第9期121卷 791-794页

作者： zhang xiao-dong hu xiao-peng YIN Hang WANG Wei zhang Xin MA Lin-lin WANG Yong Kidney Transplantation Program Department of Urology Beijing Chaoyang Hospital Capital Medical University Beijing 100020 China

Background Filamentous fungal infections are associated with a high morbidity and mortality in solid organ transplants The present study aimed to investigate the aspergillus pneumonia in renal transplant recipients, and its diagnosis as well as treatment. Methods Approximately 2000 cases of renal transplants were retrospectively studied and we focused on cases hospitalized during August 1, 2005 and February 1, 2007, as the study period. The clinical database and electronic records were analyzed. Recently published literature was reviewed. Results There was more diabetes and hypertension in the infected group than in the non-infected group （86% vs 62% and 57% vs 39%, respectively）. Eighty-six percent of recipients from the infected group had delayed graft function. Seven cases with aspergillus pneumonia were identified based on either fungal culture or radiology. Of the 7 cases, 4 died in a few days after diagnosis. Liposomal amphotericin B was used as a first-line therapy. Conclusions Incidences of fungal infection are increasing among renal transplant recipients. Early diagnosis and treatment are critical steps in curing aspergillosis.

关键词： aspergillosis pneumonia, renal transplantation diagnosis treatment

在线全文

学校读者我要写书评

暂无评论

犯罪概念形式与实质的理论建构

现代法学 2005年第3期27卷 129-137页

作者：张小虎北京师范大学法律系北京100875

犯罪概念的形式与实质,是刑法理论犯罪界说的焦点,并且由此涉及到对于罪刑法定原则的贯彻。在刑法规范的框架内,犯罪的形式界定与实质界定并不是冲突的;大陆法系、英美法系犯罪成立条件的形式也贯穿着实质的判断。犯罪实质与形式的划分... 详细信息

犯罪概念的形式与实质,是刑法理论犯罪界说的焦点,并且由此涉及到对于罪刑法定原则的贯彻。在刑法规范的框架内,犯罪的形式界定与实质界定并不是冲突的;大陆法系、英美法系犯罪成立条件的形式也贯穿着实质的判断。犯罪实质与形式的划分,既是立法实际的复写,也是理论分析的必要。行为的犯罪评价可以通过肯定判断与否定判断来具体实现。基于犯罪的“形式与实质双面统一”的理念,犯罪概念与罪刑法定原则具有形式与内容的统一。

关键词：犯罪概念理论建构罪刑法定原则质刑法理论刑法规范大陆法系成立条件英美法系肯定判断犯罪评价界定立法

在线全文

学校读者我要写书评

暂无评论

贝叶斯序贯重要性积分滤波器

电子学报 2022年第4期50卷 823-831页

作者：张宏伟张小虎曹勇中山大学航空航天学院广东广州510725 中国科学院空间精密测量技术重点实验室陕西西安710119 北京东方计量测试研究所北京100029

为解决非线性滤波中存在模型歧义和预测偏差情况下似然函数、目标重要性密度函数和实际目标分布不匹配的问题,提出了贝叶斯序贯重要性积分滤波器(Bayesian Sequential Importance Quadrature Filter,SIQF).为了消减贝叶斯推理中似然函... 详细信息

为解决非线性滤波中存在模型歧义和预测偏差情况下似然函数、目标重要性密度函数和实际目标分布不匹配的问题,提出了贝叶斯序贯重要性积分滤波器(Bayesian Sequential Importance Quadrature Filter,SIQF).为了消减贝叶斯推理中似然函数和目标分布之间的偏差,通过空时软约束定义最新观测的有界似然,截断观测噪声概率密度函数以近似可行域的修正先验.为了调制重要性函数和目标分布的匹配程度,并行对修正和原始先验下的状态进行Gauss-Hermite积分,引入最大相关信息熵构建覆盖多模分布的重要性函数,从而提升序贯重要性采样的多样性和预测协方差的容错性.实验结果表明:相比无迹粒子滤波估计一维单变量增长模型,SIQF算法在无需牺牲计算复杂度的情况下平均误差减小了63%;相比多模型Rao-blackwell粒子滤波器跟踪空域机动目标,SIQF算法的均方根误差减小了33%,所需计算量降低了一个数量级.

关键词：非线性滤波贝叶斯序贯重要性积分软约束有界似然相关信息熵测度

在线全文

学校读者我要写书评

暂无评论

中国对非洲投资的环境法律争端:预防与化解

湘潭大学学报（哲学社会科学版） 2023年第2期47卷 79-83页

作者：张小虎湘潭大学法学院湖南湘潭411105

中非合作全面深化,建筑业和采矿业长期位居对非投资前列,其环境影响性和资源依赖性,导致企业屡陷环境法律争端。因此,构建对非投资环境法律争端的预防与化解机制尤为必要。建议以环境法律风险预防原则为前提,在投资审查和融资信贷过程... 详细信息

中非合作全面深化,建筑业和采矿业长期位居对非投资前列,其环境影响性和资源依赖性,导致企业屡陷环境法律争端。因此,构建对非投资环境法律争端的预防与化解机制尤为必要。建议以环境法律风险预防原则为前提,在投资审查和融资信贷过程中坚持绿色原则,提前规避争端;以替代性争议解决为手段,依托国际调解和仲裁机制,加强第三方争端解决的执行力;谨慎使用当地司法救济解决环境法律争端,合理承担责任,有效保障权益;尝试构建国际环境法庭,积极参与中非环境治理,共同应对全球气候变化。

关键词：对非投资环境法律风险预防原则法律争端解决