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Search Results: 1 - 10 of 33393 matches for " 许园园 "
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复合绝缘子在输电线路防污闪技术中的应用
Application of Composite Insulators Used in the Technology of Anti-Flashover in Transmission Lines
 [PDF]

青龙, 元帅, 赵纪宗,
Smart Grid (SG) , 2014, DOI: 10.12677/SG.2014.43015
Abstract:

电力系统运行中,高压输电线路绝缘子污闪是一种常见的事故,其对于输电线路的安全运行以及电力系统安全运行有着非常重要的影响。随着输电线路的防污闪技术研究不断深入,清扫积污、调整爬电距离、使用防污闪涂料、采用复合绝缘子等技术应运而生。其中复合绝缘子以其优良的抗污特性,被广泛应用于防污闪技术中。本文综述了绝缘子污闪的机理、输电线路防污闪措施、合成绝缘子结构特点、优良性能,及在其使用过程中的常见问题。
In the operation of power system, insulator flashover is a common accident which has serious effect on high voltage transmission line. Some methods, such as cleaning contamination, creepage distance adjustment, using anti-flashover coating and using composite insulators, have been emerged with the development of anti-flashover technology. Among those methods, the composite insulators were widely used because of its excellent stain resistance characteristics. This paper reviews the mechanism of flash insulator pollution, measures of anti-flashover, structural characteristics and excellent performance of composite insulators. Finally, frequently asked questions in the course of its use were discussed.

粒子群算法在小容量智能交流接触器设计中的应用
志红,
福州大学学报(自然科学版) , 2007,
Abstract: 针对小容量智能交流接触器,提出了一种全新的控制方案,采用3台分立的磁保持继电器作为智能交流接触器本体,进行三相电路的智能控制.将粒子群算法引入该产品的优化设计中,使其具有更加合理的电磁机构与动态特性,进一步减少了在吸合过程中产生的触头弹跳和铁心撞击,实现了吸合、吸持、分断过程的动态优化控制,提高了产品的各项性能指标.
冲击机械性能微机测控系统设计
,
南京师范大学学报(工程技术版) , 2014,
Abstract: 针对冲击机械冲击随动系统实际工况下测试的干扰因素多、测控过程复杂且多参数同步测试的特点,采用并行测试设计,研究了基于微机控制的辅助测控系统,从系统的硬件和软件两方面着手解决了在工业现场环境下,冲击机械多参数同步采集与数据处理等动态测试问题.测试结果表明系统的高精度、高可靠性及稳定性等完全满足冲击机械冲击性能的测控要求.
基于RS和GIS的山东省植被覆盖的时空演变特征及其成因研究
Vegetation Covering Spatial-Temporal Changes in Shandong Province Based on RS and GIS
 [PDF]


Geographical Science Research (GSER) , 2015, DOI: 10.12677/GSER.2015.43011
Abstract:
当前山东省处于快速发展阶段,经济的高速增长以及粗放的发展模式使得山东省的土地利用方式以及植被覆盖发生了深刻变化。本论文以山东省为研究区域,利用2002年至2011年1 km分辨率的MODIS NDVI数据,在ENVI技术的支持下,分析了山东省植被覆盖变化情况。研究结果表明气候干旱、多元化开发以及农业耕种是导致山东省植被覆盖变化的主要原因,山东省整个区域的植被指数空间分布具有明显的地域特征,MODIS-NDVI植被指数可以用来对不同的植被种类进行监测,还可以对同种植被的不同生长期变化进行监测,本研究的研究结果可以为政府环境管理经济规划等工作提供基础信息支持。
Shandong Province is in the stage of rapid development at present. Rapid economic growth and extensive development model make the land use and vegetation cover undergo profound changes in Shandong Province. Based on the MODI S NDVI data with 1 km resolution, the vegetation cover changes of Shandong Province from 2002 to 2011 were analyzed in this paper supporting by the ENVI technology. The results showed that drought, fixed assets investment and crop planting area may be the main reasons for vegetation coverage changes of Shandong Province. Vegetation index has an obvious spatial difference in Shandong and MODIS-NDVI can be used to monitor different vegetation types and their growing periods. This paper can provide a basic information support for governing environment and economic planning.
高校实验室管理体制的改革与发展
Reform and Development of Laboratory Management System in Universities
 [PDF]

, 张伟
Advances in Education (AE) , 2016, DOI: 10.12677/AE.2016.64025
Abstract:
高校实验室管理体制经历了从三级管理模式到二级管理模式的转换,并正在努力整合实验室,向一级管理模式发展。各高校针对目前实验室体系中存在的弊端,从转变观念,加强高校实验技术队伍建设;加大经费投入等5个角度着手,改革和创新实验室管理体制。曲师大教师教育实训中心根据自身情况,建立了中心隶属于实验与设备管理处,挂靠在教师教育学院,主任责任制,并面向全校师生的管理模式,取得了良好的效果和声誉。
The laboratory management system in universities had completed the transform from the third class management to the second class, and the management system is making great efforts to de-velop the first class. Currently, because of some drawbacks of the present laboratory system, universities take some measures to improve the development and reform of the laboratory system mainly including transforming the idea, strengthening the construction of the experimental technical team in colleges and universities, and increasing the lab financial input etc. 5 parts. More- over, Qufu Normal University Teacher education training center develops the lab management system based on their self-conditions, and receives excellent results.
压缩载荷下复合材料整体加筋板渐进损伤非线性数值分析
,希武,郭树祥
复合材料学报 , 2011,
Abstract: 建立了考虑脱粘的复合材料整体加筋板渐进损伤有限元分析模型。该模型采用界面单元模拟筋条与壁板之间的连接界面,连接界面和复合材料层板分别采用Quads准则和Hashin准则作为失效判据,基于ABAQUS软件,建立了含连续损伤状态变量的材料刚度退化方案。基于该模型,采用非线性有限元方法研究了压缩载荷下复合材料整体加筋壁板在考虑初始几何缺陷时的破坏过程,分析了结构相应失效模式的细观损伤机制;详细讨论了轴向刚度比对结构承载能力及破坏模式的影响。结果表明:考虑脱粘损伤的有限元模型能有效模拟加筋板的破坏过程;在加筋板铺层设计合理的情况下,增加筋条与壁板刚度比能有效提高加筋板截面单位面积的承载能力。
氟对大鼠肝功及GSH-Px基因表达影响
刘连,,,黄厚今
中国公共卫生 , 2010, DOI: 10.11847/zgggws2010-26-05-81
Abstract: ?目的探讨不同浓度氟对大鼠肝功和谷胱苷肽过氧化物酶(GSH-Px)基因表达及肝细胞超微结构影响。方法在饮水中加入不同剂量氟化钠喂饲大鼠30d后,测定血清氟含量、门冬氨酸氨基转移酶(AST)、丙氨酸氨基转移酶(ALT)活力、肝组织中GSH-Px活性及mRNA表达,观察大鼠肝细胞超微结构。结果随染氟剂量增加,各剂量组大鼠血氟浓度逐渐增加,血清中AST、ALT含量逐渐增加,呈剂量-效应关系(R=0.889,R=0.729,P<0.01);GSH-Px酶活力单位从(19.672±1.025)下降至(11.777±1.529),与对照组比较,差异有统计学意义(P<0.01);GSH-Px的mRNA表达下降(P<0.05)。中、高剂量组大鼠肝细胞超微结构可见线粒体肿胀,有较多脂肪变性。结论过量氟可能诱导GSH-Px的mRNA表达下降,使大鼠肝脏抗氧化系统受到抑制。
欧洲鹅耳枥种子层积过程中贮藏物质及酶活性的变化
祝遵凌,林庆梅,
南京林业大学学报(自然科学版) , 2013, DOI: 10.3969/j.issn.1000-2006.2013.06.031
Abstract: 对欧洲鹅耳枥种子进行变温层积处理,测定种子发芽率,淀粉、可溶性糖、蛋白质、粗脂肪含量及相关酶的活性,研究欧洲鹅耳枥种子萌发前层积过程中主要贮藏物质的含量以及相应酶活性的动态变化。结果表明:在变温层积过程中,欧洲鹅耳枥种子中淀粉、粗脂肪逐渐减少,可溶性蛋白含量先增加后减少,层积结束时较对照分别减少了39.7%、92.2%、2.3%;可溶性糖含量明显增加,较对照增加了129%;相应酶活性呈增加趋势,淀粉酶、酸性磷酸酯酶及过氧化物酶活性较对照分别增加了550%、228%、67%;变温层积150d后种子发芽率大幅度升高。说明变温层积能有效解除欧洲鹅耳枥种子的休眠,贮藏物质不断分解代谢,为种子萌发做准备。
自动驾驶场景下小且密集的交通标志检测
,有疆,赵帅,韩亚洪
- , 2018, DOI: 10.11992/tis.201706040
Abstract: 在自动驾驶场景中,交通标志的检测和识别对行车周围环境的理解至关重要。行车过程中拍摄的图片中存在许多较小的交通标志,它们很难被现有的物体检测方法检测到。为了能够精确地检测到这部分小的交通标志,我们提出了用浅层VGG16网络作为物体检测框架R-FCN的主体网络,并改进VGG16网络,主要有两个改进点:1)减小特征图缩放倍数,去掉VGG16网络卷积conv4_3后面的特征图,使用RPN网络在浅层卷积conv4_3上提取候选框;2)特征拼层,将尺度相同的卷积conv4_1、conv4_2、conv4_3层的特征拼接起来形成组合特征(aggregated feature)。改进后的物体检测框架能够检测到更多的小物体,在驭势科技提供的交通标志数据集上取得了很好的性能,检测的准确率mAP达到了65%。
In self-driving scenarios, the detection and recognition of traffic signs is critical to understanding the driving environment. The plethora of small traffic signs are hard to detect by the existing object detection technology. To detect these small traffic signs accurately, we propose the use of the shallow network VGG16 as the R-FCN’s backbone and the modification of the VGG16 network. There are mainly two improvements in the VGG16 network. First, we reduce the multiple zooming of feature maps, remove the feature maps behind the VGG16 network convolution conv4_3, and use the RPN network to extract the region proposal in the shallow convolution conv4_3 layer. We then concatenate the feature maps. The features of the layers of the convolutions conv4_1, conv4_2, and conv4_3 are adjoined to form an aggregated feature. The improved object detection framework can detect more small objects. We use a dataset of traffic signs to test the performance and mAP accuracy
新型种植手术器械在非翻瓣上颌窦内提升术的应用 Clinical Application of Implant Instruments in the Elevation of Maxillary Sinus Floor
陈建钢,,
- , 2016,
Abstract: 目的:观察和评估几类实用新型种植手术器械的临床疗效,旨在提高上颌窦内提升术的安全性和精准性。方法:对20例患者行上颌窦内提升术,共植入种植体25枚,术中应用牙龈刻度探针、有刻度标识的环切刀和先锋钻,测量种植区黏骨膜组织厚度,以利于非翻瓣盲视条件下更准确地确定上颌窦底位置。结果:全部病例无1例发生上颌窦底穿通,上颌窦提升厚度为2-4mm,术后创口无需缝合和拆线,无肿胀疼痛和创口感染。结论:几种改良式种植手术工具发挥出良好的微创效果,既能减少上颌窦底穿通的风险、提高了手术安全性,又能有效减轻术后反应,值得临床推广应用
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