检索结果-南通市图书馆

兵工学报 2022年第S01期43卷 189-195页

作者：刘勤姬广振曹璞琳李娟刘英中国兵器科学研究院北京100089 中兵勘察设计研究院有限公司北京100053

武器装备机械系统结构复杂、故障模式多、相关性强,工作过程承受振动、冲击、高温等复杂工作环境应力作用。从复杂机械系统及其关键件的故障机理研究出发,分析工作条件、环境应力及时间对系统退化或故障的影响,利用仿真和试验相结合建... 详细信息

武器装备机械系统结构复杂、故障模式多、相关性强,工作过程承受振动、冲击、高温等复杂工作环境应力作用。从复杂机械系统及其关键件的故障机理研究出发,分析工作条件、环境应力及时间对系统退化或故障的影响,利用仿真和试验相结合建立零部件、系统可靠性模型,提出一套基于故障物理的复杂机械系统可靠性设计分析流程和方法,包括故障物理模型建立、零部件或结构的可靠性设计分析、机械系统或机构可靠性设计分析等。结果表明:该项技术应用于武器装备关键系统,可以有效预测和评估系统的可靠度和寿命,并提高装备的可靠性水平。

关键词：复杂机械系统系统可靠性故障物理可靠性分析

在线全文

学校读者我要写书评

暂无评论

SIBR增韧PS的微观结构

合成树脂及塑料 2005年第3期22卷 58-61页

作者：杨娟王健刘滢中国石油化工股份有限公司北京燕山分公司研究院北京102500

采用透射电子显微镜和扫描电子显微镜观察了苯乙烯-丁二烯-异戊二烯三元橡胶(SIBR)增韧制备的具有超高冲击强度的高抗冲聚苯乙烯(HIPS)的微观结构,发现SIBR增韧HIPS的形态结构不是传统的海-岛结构,而是一种形状规整的立体网络结构。冲... 详细信息

采用透射电子显微镜和扫描电子显微镜观察了苯乙烯-丁二烯-异戊二烯三元橡胶(SIBR)增韧制备的具有超高冲击强度的高抗冲聚苯乙烯(HIPS)的微观结构,发现SIBR增韧HIPS的形态结构不是传统的海-岛结构,而是一种形状规整的立体网络结构。冲击断面照片显示SIBR增韧主要以剪切屈服为主,从而增强了材料的抗冲击性能。

关键词： SIBR 微观结构增韧高抗冲聚苯乙烯苯乙烯-丁二烯电子显微镜观察透射电子显微镜高冲击强度抗冲击性能异戊二烯形态结构 HIPS 网络结构冲击断面橡胶

Bladder Bleeding Due to Placenta Percreta:Report of Four Cases and Management Discussion

在线全文

学校读者我要写书评

暂无评论

Maternal-Fetal Medicine 2021年第4期3卷 285-291页

作者： Huidan Zhao Xianlan Zhao Chuanna liu ya Tao yan Zhou Department of Obstetrics The First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenan 450052China Obstetric Emergency and Critical Care Medicine of Henan Province ZhengzhouHenan 450052China

Placenta percreta with bladder bleeding can occur during gestation or postpartum,posing a great threat to both mother and *** it is rare and lacks standard management *** reported four cases suffering from bladder bleeding caused by placenta percreta even with hemorrhagic shock admitted between January 1^(st),2011 and December 31^(th),2020 in The First Affiliated Hospital of Zhengzhou *** information,including age,gravidity and parity,ultrasound and magnetic resonance imaging manifestations,onset gestational age,bladder bleeding volume,clinical manifestations under bleeding,diagnosis,hemostatic methods,hospital stay,treatment cost,and prognosis,are *** cases had bladder bleeding during the second trimester,respectively on the 22^(+3)and 23^(+5)*** was terminated *** other two cases had bladder bleeding on the 2nd day post near-term cesarean section when *** the four cases achieved successful hemostasis following angiography and concomitant embolization for iliac vessels,and one of them received electrocoagulation hemostasis under cystoscopy,but *** all had favorable clinical outcomes and had no long-term *** neonatal outcome in the two cases that bladder hemorrhage occurred after near-term c-section was *** newborns did not survive in two cases in which bladder hemorrhage occurred at the second trimester of *** termination of pregnancy is recommended when such a condition develops during *** of bladder bleeding is relatively easy,for it is characterized by fast speed and large volume,with concomitant distension of the lower abdomen,blood discharge from the urethral orifice,or the indwelling *** embolization is an effective means to treat bladder bleeding caused by placenta percreta,while electrocoagulation hemostasis under cystoscopy must be applied with great *** the pregnant women with a high risk of placenta per

关键词： Placenta accreta Placenta percreta Bladder hemorrhage Early diagnosis

纤维增强树脂基复合材料防弹性能影响因素及破坏机制

在线全文

学校读者我要写书评

暂无评论

复合材料学报 2017年第9期34卷 1960-1972页

作者：焦亚男何业茂周庆刘婷天津工业大学复合材料研究所先进纺织复合材料教育部重点实验室天津300160 北京普诺泰新材料科技有限公司北京102200

以超高分子量聚乙烯(Ultra High Molecular Weight Polyethylene,UHMWPE)纤维、S-玻璃纤维、芳纶1414纤维和杂环芳纶纤维增强聚烯烃(Polyolefin,PO)和水性聚氨酯(Waterborne Polyurethane,WPU)树脂,采用热压工艺制备正交单向无纬(UD)结构复合材料装甲板;通过装甲板弹道极限速度测试,研究了纤维增强树脂基复合材料装甲板防弹性能的影响因素;通过体视显微镜观察装甲板侵彻破坏形貌,分析了纤维增强树脂基复合材料的破坏机制。结果表明:UHMWPE纤维增强PO树脂基复合材料的防弹性能与UHMWPE纤维的强度和模量呈正相关,但纤维模量对复合材料防弹性能的影响随着纤维模量的增大而逐渐变弱;在WPU树脂体系下,四种纤维的防弹性能由高到低依次是UHMWPE纤维、杂环芳纶纤维、芳纶1414纤维、S-玻璃纤维;纤维增强树脂基复合材料装甲板中纤维破坏方式有迎弹面纤维被剪切冲塞、中部被纤维拉伸变形后剪切、背弹面纤维被拉伸断裂,中部纤维拉伸变形是消耗子弹动能的主要方式。

关键词：层压复合材料纤维性能防弹性能弹道极限速度比吸收能破坏机制

Heredity and gene mapping of a novel white stripe leaf mutant in wheat

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2021年第7期20卷 1743-1752页

作者： LI Hui-juan JIAO Zhi-xin Nl Yong-jing JIANG Yu-mei LI Jun-chang PAN Chao ZHANG Jing SUN Yu-long AN Jun-hang liu Hong-jie LI Qiao-yun NIU Ji-shan National Centre of Engineering and Technological Research for Wheat/National Key Laboratory of Wheat and Maize Crop Science/Henart Agricultural University Zhengzhou 450046P.R.China Shangqiu Academy of Agricultural and Forestry Sciences Shangqiu 476000P.R.China

Spotted leaf(spl)mutant is a type of leaf lesion mimic mutants in *** obtained some lesion mimic mutants from ethyl methane sulfonate(EMS)-mutagenized wheat(Triticum aestivum L.)cultivar Guomai 301(wild type,WT),and one of them was named as white stripe leaf(wsl)mutant because of the white stripes on its *** we report the heredity and gene mapping of this novel wheat mutant *** are many small scattered white stripes on the leaves of wsl throughout its whole growth *** the plants grew,the white stripes became more severe and the necrotic area *** mutant wsl grew only weakly before the jointing stage and gradually recovered after *** length and width of the flag leaf,spike number per plant and thousand-grain weight of wsl were significantly lower than those of the *** analysis indicated that the trait of white stripe leaf was controlled by a recessive gene locus,named as wsl,which was mapped on the short arm of chromosome 6 B by SSR marker *** SSR markers in the F2 population of wsl×CS were linked to wsl in the order of Xgpw1079–Xwmc104–Xgwm508-wsl–Xgpw7651 at 7.1,5.2,8.7,and 4.4 c M,respectively and three SSR markers in the F2 population of wsl×Jimai 22 were linked to wsl in the order of Xgwm508–Xwmc494–Xgwm518-wsl at 3.5,1.6 and 8.2 c M,*** comparison to the reference genome sequence of Chinese Spring(CS),wsl is located in a 91-Mb region from 88 Mb(Xgwm518)to 179 Mb(Xgpw7651)on chromosome 6 *** wsl is a novel germplasm for studying the molecular mechanism of wheat leaf development.

关键词： wheat(Triticum aestivum L.) mutant white stripe leaf(wsl) heredity gene mapping

Temperature Simulation of Berry Slices Under Microwave Vacuum Puffing Conditions

在线全文

学校读者我要写书评

暂无评论

Journal of Northeast Agricultural University(English Edition) 2012年第4期19卷 75-78页

作者： liu Hai-jun Lin Zhen Zheng Xian-zhe liu Cheng-hai Song Xiang-yu liu Dai-ya College of Engineering Northeast Agricultural University College of Food Science Heilongjiang Bayi Agricultural University College of Building Materials and Industrial Technology Heilongjiang College of Construction

In order to study the temperature simulation of berry slices in microwave vacuum puffing process, numerical simulation method was used to simulate the temperature in different time according to theoretical calculation result and the deviation had been verificated throughout the experiment. The better uniform of temperature between experiment and simulation could be concluded except in the period of rapid temperature increase. The temperature reached the high point of 130.25℃ in the middle point of slices at 100 s, while the temperature was over 50℃ in external parts of slices for the reason of thermal diffusion. Conclusions could be drawn that the model was effective and numerical analysis could simulate the temperature simulation for berry leather in microwave vacuum puffing process.

关键词： microwave vacuum puffing simulation temperature raspberry

Cancer and Thrombosis

在线全文

学校读者我要写书评

暂无评论

血栓与止血学 2011年第4期17卷 147-148页

作者：刘敏涓 Cancer Hospital of Guangzhou Medical College

Relationship between cancer and thromboembolic disease,the research has been going on for more than a *** trousseau in 1865 first reported the formation of venous thrombosis prone patients with gastric *** will be can... 详细信息

关键词： Cancer Thrombosis

基于双领航者的多AUV协同导航系统可观测性分析

在线全文

学校读者我要写书评

暂无评论

系统工程与电子技术 2013年第11期35卷 2370-2375页

作者：高伟刘亚龙徐博哈尔滨工程大学自动化学院黑龙江哈尔滨150001

针对双领航自主水下机器人(autonomous underwater vehicle,AUV)协同导航系统编队设计对系统可观测性的要求,采用非线性系统李导数可观测性分析方法以及矩阵条件数分析理论对基于相对距离量测的双领航者协同导航方法的可观测性进行了定... 详细信息

针对双领航自主水下机器人(autonomous underwater vehicle,AUV)协同导航系统编队设计对系统可观测性的要求,采用非线性系统李导数可观测性分析方法以及矩阵条件数分析理论对基于相对距离量测的双领航者协同导航方法的可观测性进行了定性和定量分析,得出了系统可观测性大小取决于主从AUV间的距离向量以及从AUV速度向量之间的相互关系。针对从AUV处于运动、静止两种状态,分别采用扩展卡尔曼滤波技术对双领航者协同导航算法进行了不同航迹条件下的仿真,对系统的可观测性条件进行了验证。

关键词：协同导航非线性系统可观测性分析李导数条件数

Actuator Fault Estimation Based On Adaptive Iterative Learning Algorithm For Nonlinear Periodic Systems

在线全文

学校读者我要写书评

暂无评论

Actuator Fault Estimation Based On Adaptive Iterative Learni...