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Search Results: 1 - 10 of 282908 matches for " 张忠如 "
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巢湖十五里河不同水力特性区沉积物及间隙水营养盐的分布特征
,
环境科学学报 , 2012,
Abstract: 为揭示水力特性对小河流沉积物及间隙水中氮磷营养盐分布特征的影响,在巢湖十五里河河道上,选择支流交汇处、弯道淤积处、弯道冲刷处、河岸坍落处、水生植物生长区、平直河段、河内浅滩等7种水力特性类型,采集深度约40cm的沉积物柱状样,并按2cm厚度现场分层,得到136个样品.在实验室分析测试的基础上,解析沉积物与间隙水氮磷垂直剖面特征及沉积物-上覆水界面氮磷营养盐的源/汇关系,拟合间隙水剖面NH4+-N、NO3--N和PO43--P浓度,并对采样点位进行聚类分析.研究结果表明:不同水力特性区沉积物氮磷含量差异明显;弯道冲刷处和河岸坍塌处间隙水剖面NH4+-N、NO3--N和PO43--P浓度相对较低,且垂直变化不大,但在水生植物生长区则变化明显;不同水力特性区的水-土界面NH4+-N、NO3--N源/汇关系,具有很好的一致性,而PO43--P则差异明显;在沉积深度0~16cm范围内,除水生植物生长区外,其它各水力特性区间隙水NH4+-N、NO3--N和PO43--P浓度在垂直剖面基本上都可以借助指数函数y=exp(a+bx+cx2)拟合,这与湖泊、水库等宽阔水域存在一定差异.
基于连续感知信息的认知无线电普适性框架
,贤达,丁国
北京邮电大学学报 , 2015, DOI: 10.13190/j.jbupt.2015.04.021
Abstract: 认知无线电网络中,受当前频谱感知和功率分配概念的束缚,次用户系统的频谱利用率和信道容量仍十分有限.分析了传统的认知无线电框架,提出了一种基于连续感知信息的普适性框架,即次用户在得到感知信息后,不再对主用户是否存在进行二元判决,而是根据连续感知信息直接进行功率分配.分别在连续功率分配和多电平功率分配的场景下进行了数学建模,分析结果表明,所提出的普适性框架给出了认知无线电系统性能的理论上限,而传统的3种认知无线电框架仅是所提出的普适性框架的特殊情况.
添加剂氟代乙烯碳酸酯对锂离子电池低温性能影响的机制研究
卞锋菊,,杨勇
电化学 , 2013,
Abstract: 本文通过磷酸铁锂/碳电池研究了电解液添加剂氟代乙烯碳酸酯(FEC)对电池低温性能的影响.电池充放电实验证明,FEC添加剂能够在负极表面形成良好的固体电解质界面层(SEI).电解液中添加5%FEC后,电池-40oC低温放电容量保持率可以从31.7%提高至43.7%,还提高了电池放电电压平台.交流阻抗测试表明,FEC的加入能够有效降低电池的界面传荷阻抗(Rct).参比电极测试表明,其主要是降低了碳负极的低温极化.
视频移动侦测技术在城市交通管理中的应用
林宝,,熊壮
重庆大学学报 , 2008, DOI: 10.11835/j.issn.1000-582X.2008.08.016
Abstract: 针对城市交通管理中的交通红绿灯计算机监控系统采用地埋感应线圈来识别红灯禁行区车辆的缺陷,描述在该计算机监控系统中如何采用视频移动侦测技术(VMD),取代地埋感应线圈来识别道路红灯禁区中行使的车辆,减少安置地埋线圈时对路面造成的损坏。分析应用该技术的可行性,硬件的可实现性。阐述如何通过计算机程序获取摄相机自动抓拍的交通红绿灯路口上行驶的机动车的违章行使照片和道路交通状况信息的方法。
Distribution characteristics of nutrients in core sediments and interstitial water from different hydraulic property zones in Shiwuli Stream, Chaohu Lake
巢湖十五里河不同水力特性区沉积物及间隙水营养盐的分布特征

LI Ruzhong,ZHANG Liang,
,

环境科学学报 , 2012,
Abstract: To investigate the effects of hydraulic properties on nutrient concentration profiles of sediment and interstitial water in stream/creek, seven types of hydraulic characteristic zones were chosen in the Shiwuli Stream, Chaohu Lake. The core sediments about 40 cm thick were collected in each characteristic zone and sliced in-situ with a thickness of 2 cm, and then a total of 136 samples was obtained. According to the measured data, the vertical profiles of nitrogen and phosphorus contents both in sediment and interstitial water were illustrated, and the cluster analysis was carried out for the sampling sites. Moreover, the source-sink relationship of each of NH4+-N, NO3--N and PO43--P at the sediment-overlying water interface was explored and their vertical concentration profiles in interstitial water were modeled as well. Study results show that there are significant differences both in the nutrient content levels and distribution characteristics in sediments for the seven hydraulic characteristic zones. There are lower concentrations and inconsiderable vertical variability for NH4+-N, NO3--N and PO43--P in interstitial water in both the erosion zone on the bend and bank failure zone, but a remarkable variation characteristic was present in the growing zone of aquatic plants. At the sediment-overlying water interface, there is a good agreement on the source-sink relationship of nutrients except PO43--P, and within the depth of 0~16 cm, the concentration profiles of nutrients in interstitial water can be modeled by using exponential function y=exp(a+bx+cx2) except for the growing zone of aquatic plants, which is different from the lake or reservoir waters.
应用酚-SDS法提纯新城疫病毒基因组RNA
吴艳涛 , 刘秀梵 , , 刘伟
扬州大学学报(农业与生命科学版) , 1996,
Abstract: ????应用酚-SDS法提纯新城疫病毒基因组RNA吴艳涛,刘秀梵,张如宽,刘伟忠(江苏农学院动物医学系,扬州225009)新城疫病毒(NDV)属副粘病毒科,为有囊膜的单链、负极性RNA病毒,基因组RNA全长15kb。开展NDV分子生物学研究,首先需要提取完整...
锂离子电池正极材料锂镍氧化物研究新进展
刘汉三,杨勇,,林祖赓
电化学 , 2001,
Abstract: 锂镍氧化物是目前高容量大功率锂离子电池正极材料的主要候选材料之一.本文详细介绍了锂镍氧化物作为锂离子电池正极材料的实用化困难与其结构的内在联系,以及解决这些困难所进行的合成方法和掺杂改性研究的概况.探索新的合成方法以及多组分掺杂改性应是今后锂镍氧化物的研究方向
新城疫病毒f48e8株融合蛋白基因的克隆
吴艳涛,刘秀梵,,刘伟
牲畜兽医学报 , 1997,
Abstract:
无约束段对工字形内芯防屈曲支撑滞回耗能性能的影响
Influence of Unconstrained Segments on Hysteretic Energy Dissipation Performance of Buckling-restrained Braces with H-section Core

,,,,周茗,太亮
- , 2017,
Abstract: 设计了12个无约束段的防屈曲支撑构件,利用ABAQUS软件对其进行有限元分析,研究无约束段长度、是否利用槽钢加强无约束段及加强槽钢的长度和厚度对构件滞回耗能性能及承载力的影响。结果表明:无约束段长度对防屈曲支撑构件滞回耗能性能及承载力影响显著,当无约束段长度与构件在轴力作用下产生的最大位移近似相等时,构件耗能效果更明显;经槽钢加强的构件具有良好的滞回耗能性能及承载力;无约束段加强槽钢的长度对构件滞回耗能性能与承载力影响显著,加强槽钢的长度为无约束段长度的2倍时,构件具有更好的滞回耗能性能与承载力;加强槽钢的厚度对构件的滞回耗能性能与承载力影响不大,设计构件时可适当减小槽钢的厚度以提高材料的利用率。
12 different buckling??restrained braces with unconstrained segments were designed, and finite element analysis was carried by ABAQUS software to study the influences of unconstrained length, whether the channel strengthened unconstrained segment or not, and the channel with different lengths and thicknesses on the hysteretic energy dissipation and bearing capacity of components. The results show that the length of the unconstrained segment has a significant influence on the hysteretic energy dissipation performance and bearing capacity. The influence of energy dissipation is more obvious when the length of unconstrained segment is equal to the maximum displacement of component under axial force. The components strengthened by channels have good hysteretic performance and bearing capacity. The length of unconstrained segment strengthened by the channel has obvious influence on the hysteretic energy dissipation performance and bearing capacity. When the channel length is 2 times than unconstrained segment length, the components have better energy dissipation and bearing capacity. Strengthening channel thickness has little effect on the hysteretic behavior and bearing capacity of components, so the thickness of the channel can be reduced in design to improve the utilization rate of materials
塔中地区晚燕山——喜马拉雅期油气调整与热液活动的关系
兴阳,水昌,罗平,,,涂建琪
科学通报 , 2007,
Abstract: 早期海相油藏的后期调整改造是塔里木盆地油气藏的重要特征之一.大规模的油气调整与强烈的区域构造活动有关,并伴随有成岩流体、成矿流体等盆地流体的大规模运移.塔中地区奥陶系碳酸盐岩构造断裂溶扩缝及岩溶风化壳溶洞内萤石等热液矿物烃类包裹体的发育,钻井证实具矿床规模的萤石脉也是重要的油气储集层,形成萤石热液成矿与油气运移成藏独特的伴生或叠加关系.结合区域构造背景与萤石成矿环境,通过热液矿物电子自旋共振测年、包裹体激光拉曼、群体包裹体烃类化石等分析后证实,晚燕山—喜马拉雅期(110.4~30.8Ma)塔中地区发生了成矿热液与成藏流体的大规模运移事件,为重要的油气调整期,喜马拉雅期(34.3Ma以来)为重要的油气成藏期.
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