检索结果-南通市图书馆

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

挤压态WE71镁合金热压缩变形行为

塑性工程学报 2024年第5期31卷 132-138页

作者：敖尚龙卜德豪袁家伟陈东杰周勇西南铝业(集团)有限责任公司重庆401326 北京有色金属研究总院北京100088 有研工程技术研究院有限公司北京101407 黄淮学院建筑工程学院河南驻马店463000

通过热模拟实验研究了挤压态WE71镁合金在变形温度为653~773 K、应变速率为0.001~1 s^(-1)条件下的热压缩变形行为,并采用EBSD对热加工图中的失稳区和可加工区的微观组织、动态再结晶过程进行了分析。结果表明,WE71镁合金属于正应变速... 详细信息

通过热模拟实验研究了挤压态WE71镁合金在变形温度为653~773 K、应变速率为0.001~1 s^(-1)条件下的热压缩变形行为,并采用EBSD对热加工图中的失稳区和可加工区的微观组织、动态再结晶过程进行了分析。结果表明,WE71镁合金属于正应变速率敏感材料,峰值应力随变形温度的升高逐渐下降,随应变速率的增大逐渐升高;在653 K和0.1 s^(-1)条件下开始发生动态再结晶,随着应变速率的降低,动态再结晶分数增加且平均晶粒尺寸减小,随着变形温度的增加,动态再结晶分数增加,但变形温度过高会使平均晶粒尺寸有所增大。挤压态WE71镁合金的变形失稳区主要为低温、高应变速率条件,最佳热加工工艺条件为733 K≤T≤773 K,0.001 s^(-1)≤ε·≤0.01 s^(-1)。

关键词： WE71镁合金热压缩流变应力动态再结晶

A POSTERIORI ERROR ESTIMATE OF THE DSD METHOD FOR FIRST-ORdeR HYPERBOLIC EQUATIONS

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2002年第6期23卷 732-740页

作者： KANG Tong(康彤) YU de-hao(余德浩) State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and System Science Chinese Academy of Sciences Beijing 100080 P R China State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and System Science Chinese Academy of Sciences Beijing 100080 P R China

A posteriori error estimate of the discontinuous-streamline diffusion method for first-order hyperbolic equations was presented, which can be used to adjust space mesh reasonably. A numerical example is given to illus... 详细信息

关键词： posteriori error estimate discontinuous-streamline diffusion method first-order hyperbolic equation

A methodological framework of landslide quantitative risk assessment in areas with incomplete historical landslide information

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 2665-2679页

作者： LI Xia CHENG Jiu-Long YU de-hao College of Geoscience and Surveying Engineering China University of Mining and Technology(Beijing)Beijing 100083China Research Institute of Engineering design Beijing 100083China

Landslide risk assessment(LRA)is of great significance to hazard prevention and ***,the historical landslide information is incomplete in most areas,which makes the landslide quantitative risk assessment(LQRA)extremely *** research proposed a set of frameworks for LQRA,so as to achieve LQRA in areas with incomplete historical landslide ***,we constructed the convolutional neural network(CNN)model suitable for landslide susceptibility assessment(LSA)by studying the structure and hyperparameters optimization of ***,we proposed a method to calculate the temporal probability by using the Poisson model based on the time range of historical landslides occurrence,and then conducted landslide hazard assessment(LHA).Then,we established a mathematical model for landslide intensity of shallow landslide based on landslide area and slope,aiming at solving the problem that it is difficult to calculate landslide intensity due to the lack of landslide volume and *** on the landslide intensity and the hazard-resistant capacity of the element at risk,we assessed the landslide ***,population risk map and economic risk map are obtained based on the landslide hazard,vulnerability,and estimated value of the elements at *** proposed LQRA framework was applied to Tumen City,China for testing and field *** the results,the CNN model built can help improve the accuracy of *** proposed temporal probability calculation method is conducive to the completion of LHA in areas with incomplete historical landslide *** established landslide intensity mathematical model has certain *** the landslide risk map is obtained through appropriate simplification and substitution estimation,its final value cannot be used as an accurate prediction of future losses,but it can be used as a reference for the extent of potential losses,so as to determine the areas where hazard prevention and

关键词： Landslide Quantitative risk assessment Convolutional neural network Hazard assessment Vulnerability

Preparation of AlN thin films for film bulk acoustic resonator application by radio frequency sputtering

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第3期10卷 464-470页

作者： Kan LI hao JIN de-miao WANG Yi-fei TANG department of Information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China

Aluminum nitride （AlN） thin films with high c-axis orientation have been prepared on a glass substrate with an Al bottom electrode by radio frequency （RF） reactive magnetron sputtering. Based on the analysis of Berg＇s hysteresis model, the improved sputtering system is realized without a hysteresis effect. A new control method for rapidly depositing highly c-axis oriented AlN thin films is proposed. The N2 concentration could be controlled by observing the changes in cathode voltage, to realize the optimum processing condition where the target could be fixed stably in the transition region, and both stoichiometric film composition and a high deposition rate could be obtained. Under a 500 W RF power of a target with a 6 cm diameter, a substrate temperature of 450 ℃, a target-substrate distance of 60 mm and a N2 concentration of 25%, AlN thin film with preferential （002） orientation was deposited at 2.3 μm/h which is a much higher rate than previously achieved. Through X-ray diffraction （XRD） analysis, the full width at half maximum （FWHM） of AlN （002） was shown to be about 0.28°, which shows the good crystallinity and crystal orientation of AlN thin film. With other parameters held constant, any increase or decrease in N2 concentration results in an increase in the FWHM of AlN.

关键词： Aluminum nitride (A1N) Piezoelectric thin film Radio frequency (RF) reactive sputtering Preferred orientation,Film bulk acoustic resonator (FBAR)

在线全文

学校读者我要写书评

暂无评论

基于改进YOLOv5s的花生仁检测系统

信息技术 2024年第9期48卷 168-175,185页

作者：刘居林李德豪张振豪员玉良青岛市即墨区第一职业中等专业学校山东青岛266200 青岛农业大学机电工程学院山东青岛266109

为提升对花生仁的检测水平,文中设计了基于改进YOLOv5s的花生仁检测系统。在YOLOv5s神经网络模型引入MobileNet V2模块和CBAM注意力机制后,将其部署到检测系统中。由实验结果可知,部署改进后的神经网络检测系统,检测精度达到98.26%,检... 详细信息

为提升对花生仁的检测水平,文中设计了基于改进YOLOv5s的花生仁检测系统。在YOLOv5s神经网络模型引入MobileNet V2模块和CBAM注意力机制后,将其部署到检测系统中。由实验结果可知,部署改进后的神经网络检测系统,检测精度达到98.26%,检测速度提升至改进前的4倍,且权重文件减小了10.5 MB。由此可见,该花生仁检测系统能实现对花生仁的快速、准确检测。

关键词：花生仁检测模型改进花生仁数据集模型训练最优模型

A detailed View of PLGA-m PEG Microsphere Formation by Double Emulsion Solvent Evaporation Method

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2015年第7期33卷 955-963页

作者： Shui-bin Feng de-hao Fu Lei Nie Peng Zou 索进平 State Key Laboratory of Material Processing and Die and Mould Technology College of Materials Science and Engineering Huazhong University of Science and Technology department of Orthopedics Union Hospital Tongji Medical College Huazhong University of Science and Technology

PLGA, m PEG diblock copolymer was synthesized by bulk ring-opening polymerization method. The double emulsion solvent evaporation method was used to prepare bovine serum albumin（BSA）-loaded microspheres. Optical microscopy was used to observe the whole microsphere fabrication process. It is confirmed that the proportion of inner aqueous phase is one of the most critical factors that determines the morphology of microspheres. Double emulsion droplets which have appropriate amount of inner aqueous phase can form closed and dense microspheres, while, too much inner aqueous phase will cause a collapse of the double emulsion droplets, resulting in a loss of drug. The proportion of inner aqueous phase was varied to prepare microspheres of different morphology. The results show that with increasing the amount of inner aqueous phase, a higher percent of broken microspheres and lower encapsulation efficiency appeared, and also, a more severe initial burst release and faster release rate.

关键词： Microspheres PLGA-m PEG Morphology Encapsulation efficiency Release profile

盾构施工引起上部既有桥梁病害及处理案例分析

在线全文

学校读者我要写书评

暂无评论

广州建筑 2024年第4期52卷 58-62页

作者：黄荣超张午阳左德豪广州市房屋开发建设有限公司广州510400 广州市市政工程试验检测有限公司广州510520 广东省装配式地下结构检测与监测工程技术研究中心广州510520

以中南地区某区间隧道及出入段线隧道下穿既有桥梁为背景案例,分析了四条盾构隧道施工引起桥梁桩基沉降变形及桥梁病害的特征及机理。根据桩基沉降变形及桥梁病害特征,提出采用桩基后压浆、桥面板UHPC增大截面、盖梁自密实混凝土增大截... 详细信息

以中南地区某区间隧道及出入段线隧道下穿既有桥梁为背景案例,分析了四条盾构隧道施工引起桥梁桩基沉降变形及桥梁病害的特征及机理。根据桩基沉降变形及桥梁病害特征,提出采用桩基后压浆、桥面板UHPC增大截面、盖梁自密实混凝土增大截面进行加固。通过注浆前后钻孔取芯进行室内试验,分析后压浆增强土体强度的效果。结果表明:1)区间隧道比出入段线隧道埋深更大,与桩基距离更小,区间隧道两侧桩基沉降最大;2)受桩基差异沉降影响,相比于铰接墩,固结墩的受力增量更大,出现环向裂缝;3)后压浆引起桩基周边土体含水率、孔隙比减小,压缩模量、粘聚力、内摩擦角、标贯击数增大,且淤泥的强度提高最大,其中淤泥的标贯击数增大100%。土体强度的提高可有效增大桩基的承载能力。

关键词：盾构隧道桩基桥梁后压浆

Polyelectrolyte Complexes and Coacervates Formed by de novo-designed Peptides and Oligonucleotide

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第9期42卷 1333-1340,I0007页

作者： Tian-hao Ren de-Hai Liang Beijing National Laboratory for Molecular Sciences Department of Polymer Science and Engineering and the Key Laboratory of Polymer Chemistry and Physics of the Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China

The liquid-liquid phase separation of biopolymers in living cells contains multiple interactions and occurs in a dynamic *** the regulation mechanism is still a *** this work,we designed a series of peptides(XXLY)_(6)SSSGSS and studied their complexation and coacervation behavior with single-stranded ***“X”and“Y”are varied to combine known amounts of charged and non-charged amino acids,together with the introduction of secondary structures and pH *** show that the electrostatic interaction,which is described as charge density,controls both the strength of complexation and the degree of chain relaxation,and thus determines the growth and size of the *** hydrophobic interaction is prominent when the charges are ***,the secondary structures of peptides exhibit profound effect on the morphology of the phases,such as solid phase to liquid phase *** study gains insight into the phase separation under physiological *** is also helpful to create coacervates with desirable structures and functions.

关键词： Polyelectrolyte complex Coacervate Peptides Secondary structure Electrostatic interaction

松墨天牛热激蛋白MaltHSP40s基因的克隆及表达特性分析

在线全文

学校读者我要写书评

暂无评论

环境昆虫学报 2024年第4期46卷 930-940页

作者：杨华磊李慧赵培渊许丹雯仪李长燕郝德君南京林业大学南方现代林业协同创新中心南京210037 南京林业大学林学院南京210037

松墨天牛Monochamus alternatus是我国南方林区重要的蛀干害虫,也是我国重大林业外来入侵物种松材线虫Bursaphelenchus xylophilus的主要传播媒介。为探究热激蛋白HSP40在松墨天牛抵御高温胁迫中的功能,基于松墨天牛转录组数据(GenBank... 详细信息

松墨天牛Monochamus alternatus是我国南方林区重要的蛀干害虫,也是我国重大林业外来入侵物种松材线虫Bursaphelenchus xylophilus的主要传播媒介。为探究热激蛋白HSP40在松墨天牛抵御高温胁迫中的功能,基于松墨天牛转录组数据(GenBank登录号:PRJNA548205),通过RT-PCR技术克隆两条松墨天牛HSP40基因,并对其进行生物信息学分析;使用MEGA 7.0软件构建松墨天牛HSP40系统进化树;利用RT-qPCR技术检测16日龄松墨天牛雌雄成虫各组织HSP40基因在不同温度与时间处理条件(35℃、37℃、40℃、42.5℃和45℃;0 h、1 h、2 h和3 h)下和高温42.5℃处理3 h后的组织表达特性。结果表明:克隆获得松墨天牛两条HSP40基因MaltHSP40-1(GenBank登录号:MW690168)和MaltHSP40-2(GenBank登录号:MW690169),其ORF长度分别为1206 bp和1059 bp,分别编码401个和352个氨基酸,分子质量分别约为45.24 kDa和39.25 kDa,等电点分别为6.73和9.07;两条序列中均存在含有保守的HPD基序以及DNA-J结构域;蛋白三维结构中均由N端的4个α螺旋和C端的底物结合域构成。系统进化树显示:MaltHSP40-1和MaltHSP40-2分别与光肩星天牛Anoplophora glabripennis的AglaHSP40-1和AglaHSP40-2遗传距离最近。RT-qPCR结果显示,高温胁迫可诱导松墨天牛HSP40基因的转录表达,雌雄成虫的MaltHSP40-1和MaltHSP40-2分别在35℃和37.5℃的条件下开始表达上调,在40℃或42.5℃时到达峰值,雄虫HSP40的相对表达量和上调倍数均高于雌虫;MaltHSP40-1及MaltHSP40-2在松墨天牛雌雄成虫的各组织中均有表达,42.5℃处理3 h后,MaltHSP40-1及MaltHSP40-2在各组织中的相对表达量均显著上调,精巢和卵巢中相对表达量最高。本研究表明MaltHSP40-1和MaltHSP40-2作为辅助分子伴侣,参与松墨天牛抵御高温胁迫。研究结果有助于深入探究热激蛋白在松墨天牛应对高温胁迫中的作用,也为揭示气候变暖背景下松墨天牛及松材线虫病的流行成灾机理提供理论依据。

关键词：松墨天牛高温胁迫热激蛋白40 耐热性辅助分子伴侣