检索结果-南通市图书馆

High Technology Letters 2020年第4期26卷 349-359页

作者： yan Wei He lidong Zhu Gang Wang Shengli Deng Zhe Beijing Key Laboratory of Health Monitoring and Self-Recovery for High-End Mechanical Equipment Beijing University of Chemical Technology Beijing 100029 P.R.China

Base excitation is one of common excitations in rotor *** order to study the dynamic characteristics of rotor systems under base excitation and the effect of integral squeeze film dampers(ISFDs)on their dynamic characteristics,a single-disk rotor test rig,where mass imbalance and base excitation could be applied,is *** research on the rotor system response under sinusoidal base excitation conditions with different frequencies and excitation forces is performed and the effect of ISFD on the dynamic characteristics of the rotor is *** experimental results demonstrate that when the sinusoidal base excitation frequency approaches the first critical speed of the rotor system or the natural frequency of the rotor system base,strong vibration occurs in the rotor,indicating that the base excitation of the two frequencies has a greater impact on rotor system *** addition,with the increase of the base excitation force,the vibration of the rotor will be *** can significantly inhibit the vibration due to unbalanced forces and sinusoidal base excitation in rotor *** a certain extent,ISFDs can improve the effect of sinusoidal base excitation with most frequencies on rotor system response,and they have a good vibration reduction effect for sinusoidal base excitation with different excitation forces.

关键词： Jeffcott rotor dynamic characteristics base excitation integral squeeze film damper(ISFD) vibration suppression

Vestiges of the Kerguelen Mantle Plume in Southern Tibet:Evidence from 123-117 Ma Magmatism in the Dingri Area of the Central Tethys Himalaya

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2023年第4期97卷 1163-1180页

作者： yan Songtao WU Qingsong LI Hu DAI Xuejian ZHU lidong WANG Jie XIN Chongyang Civil-Military Integration Center of China Geological Survey China Geological SurveyChengdu 610036China Institute of Sedimentary Geology Chengdu University of TechnologyChengdu 610059China College of Earth Science Chengdu University of TechnologyChengdu 610059China

The widely distributed Early Cretaceous magmatism in the Tethys Himalaya(TH)of southern Tibet is related to the Kerguelen mantle *** magmatic activity products are distributed in the eastern TH,where the active age is earlier than the peak ages of the Kerguelen mantle *** study investigated magmatic activity of the Dingri area in the central TH which was coeval with the Kerguelen mantle *** intrusion in the Dingri area contains diabases and *** zircon age of diabase is 123±1 Ma,and that of monzonite is 117±1 *** and Sr-Nd isotopic analyses show that the mafic-intermediate dikes were formed in an intraplate extensional *** diabase is derived from the enriched lithospheric mantle and monzonite is derived from partial melting of the lower crust,with both magmatic evolutions being contaminated by crustal *** characteristics are similar to those of the Rajmahal-Sylhet basalt,a typical Kerguelen mantle plume *** discovery of the Dingri mafic-intermediate dikes of the central TH suggests that the TH and Rajmahal-Sylhet Traps formed a continuous mantle plume overflow magmatic belt which was a product of the continuous eruption of the Kerguelen mantle plume.

关键词： geochronology mafic-intermediate dikes Kerguelen mantle plume central Tethys Himalaya East Gondwana

在线全文

学校读者我要写书评

暂无评论

基于二分搜索的宽带多普勒模型信号捕获方法

太赫兹科学与电子信息学报 2024年第3期22卷 269-277页

作者：郭孟泽付学瀚朱立东燕贺云电子科技大学通信抗干扰全国重点实验室四川成都611731

针对深空通信等超高动态低信噪比通信场景中,传统信号捕获方法存在着动态范围不足、精确度不够以及使用窄带多普勒模型导致对接收信号近似精确度不高的问题,提出一种基于二分搜索的接收端采样率调整方法。使用宽带多普勒模型对接收信号... 详细信息

针对深空通信等超高动态低信噪比通信场景中,传统信号捕获方法存在着动态范围不足、精确度不够以及使用窄带多普勒模型导致对接收信号近似精确度不高的问题,提出一种基于二分搜索的接收端采样率调整方法。使用宽带多普勒模型对接收信号进行建模,并使用扫频余弦类信号进行多普勒频偏估计和定时估计,处理多普勒伸缩后的信号与本地信号采样率不匹配的问题。对所提方法进行同步性能仿真,仿真结果表明,所提方法采用正反扫频线性调频(UD-LFM)信号,能在信噪比为-49dB、最大多普勒频偏为2MHz的条件下,多普勒频偏估计误差小于400 Hz,定时估计误差不超过60 ns。相比不使用本文所提方法进行直接捕获,本文所提方法具有更高的捕获精确度以及更低的信噪比门限。

关键词：超高动态宽带多普勒模型低信噪比扫频余弦信号信号捕获

Experimental study on integral axial squeeze film damper to suppress longitudinal vibration of propulsion shafting

在线全文

学校读者我要写书评

暂无评论

High Technology Letters 2021年第1期27卷 76-85页

作者： Fan Wenqiang He lidong Jia Xingyun yan Wei Zhu Gang Wang Jian Engineering Research Center of Chemical Safety Ministry of Education Beijing University of Chemical TechnologyBeijing 100029P.R.China

This paper aims at investigating the effectiveness of squeeze oil film in suppressing the longitudinal vibration of propulsion shaft systems through a novel integral axial squeeze film damper(IASFD).After designing the IASFD,a propulsion shafting test rig for the longitudinal vibration control is *** vibration control experiments of the propulsion shafting are carried out under different magnitude and frequency of the excitation *** results show that both IASFD elastic support and IASFD elastic damping support have excellent vibration attenuation characteristics,and can effectively suppress the longitudinal vibration of the shaft system in a wide frequency ***,IASFD elastic damping support has a more significant vibration reduction effect than the other supports,and increasing the damping of the system has obvious effect on reducing the shafting *** an excitation force of 45 N,the maximum reduction of the vibration amplitude is 89.16%.Also,the vibration generated by the resonance phenomenon is also significantly reduced.

关键词： integral axial squeeze film damper(IASFD) propulsion shafting longitudinal vibration vibration damping

3D打印金属垫块或胫骨假体重建全膝关节置换和翻修术中的巨大骨缺损

在线全文

学校读者我要写书评

暂无评论

中华骨科杂志 2024年第4期44卷 243-249页

作者：胡鹏飞吴浩波冉季升包家鹏蒋利锋陈炜平赵翔严世贵吴立东浙江大学医学院附属第二医院骨科杭州310009

目的探讨3D打印金属垫块或胫骨假体重建全膝关节置换(total knee arthroplasty,TKA)和膝关节翻修术中巨大骨缺损的临床疗效。方法回顾性分析2018年7月至2023年12月就诊于浙江大学医学院附属第二医院骨科的存在巨大骨缺损的TKA或膝关节... 详细信息

目的探讨3D打印金属垫块或胫骨假体重建全膝关节置换(total knee arthroplasty,TKA)和膝关节翻修术中巨大骨缺损的临床疗效。方法回顾性分析2018年7月至2023年12月就诊于浙江大学医学院附属第二医院骨科的存在巨大骨缺损的TKA或膝关节翻修患者7例(7膝),其中TKA 4例、膝关节翻修术3例。男3例、女4例,年龄(58.7±7.6)岁(范围54~68岁),左膝3例、右膝4例。患者膝关节均存在骨缺损,均为AORIⅢ型,2例仅股骨存在骨缺损,4例仅胫骨存在骨缺损,1例胫骨和股骨均存在缺损,采用3D打印个性化重建治疗。比较手术前后的髋膝踝角、美国膝关节协会评分(Keen Society score,KSS),观察术后并发症情况。结果所有患者均顺利完成手术,手术时间为(189.3±35.5)min(范围125~240 min)。复杂TKA 4例,手术时间分别175、195、210、240 min,翻修术3例,手术时间分别125、180、200 min。术中出血量为(114±24.4)ml(范围100~150 ml)。5例使用3D打印金属垫块,2例使用3D打印一体式胫骨部件。所有患者均获得随访,随访时间分别为2、2、5、6、7、20、57个月。术后3个月5例患者的KSS膝评分分别为56、61、66、56、56分,大于术前的35、44、36、27、41分。术后3个月5例患者的KSS功能评分分别为45、45、45、30、45分,大于术前的30、30、15、20、20分。末次随访时髋膝踝角为181.8°±3.4°(范围177.9°~188.0°),术前为175.8°±12.4°(范围153.3°~192.1°),差异无统计学意义(t=-1.230,P=0.242)。末次随访时3D打印部件与骨面结合良好,假体位置稳固,下肢力线均正常。两组术后无一例出现切口愈合不良、感染、脂肪液化、神经损伤、下肢深静脉血栓形成、膝关节僵硬、假体周围感染及松动等并发症。结论采用3D打印金属垫块或胫骨假体重建全膝关节置换和翻修术中巨大骨缺损早期临床疗效满意,可获得比较满意的关节功能,手术安全性较好。

关键词：关节成形术,置换,膝假体失效打印,三维治疗结果

Endogenous nucleotide as drug carrier:base-paired guanosine-5’-monophosphate:pemetrexed vesicles with enhanced anticancer capability

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2020年第2期63卷 244-253页

作者： Lei Xu Chunyang Yu Dali Wang Ji Pang Leilei Shi Yue Su lidong Gong Deyue yan Xinyuan Zhu School of Chemistry and Chemical Engineering State Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghai 200240China School of Chemistry and Chemical Engineering Liaoning Normal UniversityDalian 116029China

Endogenous substance such as nucleotide as a drug carrier has been proposed as a novel drug delivery *** nucleotide guanosine-5’-monophosphate(GMP) is used to transport an anticancer drug pemetrexed disodium heptahydrate(PMX) via specific base *** endogenous nature of GMP helps to avoid biocompatibility issues that are generally accompanied with nanocarriers including cytotoxicity,immunogenicity and blood ***,the low-molecular weight of the GMP nucleotide carrier significantly boosts the drug loading capacity compared to traditional liposomes and high-molecular weight ***-bonding interaction between the carrier and drug realizes the controlled release of loaded drug,and also facilitates large scale manufacture since no additional chemical synthesis is *** importantly,in vivo experiments reveal that the base-paired GMP:PMX nanovesicles improve the target specificity and pharmacokinetic properties of PMX,and exhibit remarkably enhanced anticancer abilities compared to standalone PMX without any *** envision that this strategy could be extended to other endogenous substances and drugs bearing functional groups capable of specific interaction,and promote the construction of drug delivery systems with inherent biocompatibility,enhanced drug delivery efficacy,and a simplified preparation method.

关键词： endogenous carrier hydrogen bonding nanovesicles drug delivery cancer therapy

Versatile functions of RNA m6A machinery on chromatin

在线全文

学校读者我要写书评

暂无评论

Journal of Molecular Cell Biology 2022年第3期14卷 3-11页

作者： Tanjing Song Suli Lv Neng Li Xuefeng Zhao Xianyun Ma Yingying yan Weixia Wang lidong Sun Department of Biochemistry and Molecular Biology School of Basic Medicineongji Medical College Huazhong University of Science and TechnologyWuhan 430030China

m6A,a conserved and abundant modification on RNA,regulates RNA processing and *** m6A machinery,including writers,erasers,and readers of m6A,is indispensable for m6A installation and ***,recent studies have revealed that m6A machinery can be recruited to chromatin by pleiotropic factors,including nascent RNA,transcription factors,regulatory RNA,histone modifications,and epigenetic ***,recruitment of m6A machinery can directly regulate chromatin biology,such as transcription,DNA damage repair,and DNA recombination beyond installation of m6A on nascent ***,we discuss recent evidence showing that m6A machinery is targeted to chromatin and the direct biological consequences along with the underlying mechanisms.

关键词： m6A chromatin RNA methylation histone modifications epigenetics

温度循环自动化无人值守平台安全生产实践研究

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

今日自动化 2024年第1期 53-55页

作者：李珊宁秦琰白立冬李小奇王振营北京遥感设备研究所北京100000

推进无人值守平台建设是实现全自动化生产的必由之路.文章主要针对某航天型号温度循环试验开展无人值守平台建设研究.通过对系统硬件、软件、安全预警等方面进行升级改造,建立完善的监控机制,最终实现无人值守平台的建设.

关键词：无人值守全自动化安全预警

基于改进Canny边缘检测的堆叠货箱分割定位方法

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

测控技术 2024年第3期43卷 28-33页

作者：徐志祥孙文博邢立东高东赵炎大连理工大学机械工程学院辽宁大连116024

为了提高集装箱卸货的自动化水平,针对集装箱内堆叠货箱难分割定位的问题,提出了一种基于改进Canny边缘检测的堆叠货箱分割定位方法。通过阈值分割和形态学处理进行图像预处理,去除背景干扰,提取堆叠货箱区域图像,基于改进Canny算法对... 详细信息

为了提高集装箱卸货的自动化水平,针对集装箱内堆叠货箱难分割定位的问题,提出了一种基于改进Canny边缘检测的堆叠货箱分割定位方法。通过阈值分割和形态学处理进行图像预处理,去除背景干扰,提取堆叠货箱区域图像,基于改进Canny算法对堆叠货箱进行边缘检测,根据堆叠货箱边缘特征进行筛选并基于最小二乘法进行直线拟合,解决边缘线条不连续和虚假边缘问题,对边缘进行区域化处理,以此将堆叠货箱分割成独立的货箱区域,提取每个独立货箱的最小外接矩形,得到货箱中心点的位置信息。实验结果表明,该方法对堆叠货箱有很好的分割效果,定位精度小于5 mm,满足定位精度要求。

关键词：改进Canny边缘检测最小二乘法图像分割堆叠货箱

在线全文

学校读者我要写书评

暂无评论

基层医院收治完全性子宫破裂5例的临床分析

中国社区医师 2024年第12期40卷 22-24页

作者：王辉黄培杰姜燕赵亚敏刘立冬聊城市东阿县人民医院产科山东聊城252201

完全性子宫破裂是指子宫体部或子宫下段发生破裂,严重威胁母婴生命健康。妊娠期及分娩期早期识别并处理完全性子宫破裂,能够预防分娩不良结局。该文对5例完全性子宫破裂救治过程进行分析,同时结合子宫破裂的原因、临床表现及母婴预后展... 详细信息

完全性子宫破裂是指子宫体部或子宫下段发生破裂,严重威胁母婴生命健康。妊娠期及分娩期早期识别并处理完全性子宫破裂,能够预防分娩不良结局。该文对5例完全性子宫破裂救治过程进行分析,同时结合子宫破裂的原因、临床表现及母婴预后展开讨论。

关键词：基层医院妊娠期子宫破裂瘢痕子宫