检索结果-南通市图书馆

多周期动态循环应力下的J-A-N力磁耦合机理模型

在线全文

学校读者我要写书评

暂无评论

中国机械工程 2024年第09期35卷 1542-1547页

作者：邢海燕刘伟男陈龙徐成弋鸣颜俊杰东北石油大学机械科学与工程学院

目前的力磁耦合J-A模型未考虑钉扎场的畴壁厚度与多周期动态循环应力的影响，导致J-A模型的应力磁化数值偏大，不能准确描述早期疲劳损伤。为此，基于畴壁理论和Burgers位错理论，引入畴壁厚度因子，改进J-A模型的钉扎场方程，进一步考... 详细信息

目前的力磁耦合J-A模型未考虑钉扎场的畴壁厚度与多周期动态循环应力的影响，导致J-A模型的应力磁化数值偏大，不能准确描述早期疲劳损伤。为此，基于畴壁理论和Burgers位错理论，引入畴壁厚度因子，改进J-A模型的钉扎场方程，进一步考虑循环载荷的应力幅、循环周次N等因素，建立了多周期动态循环应力下的J-A-N力磁耦合机理模型。获得了不同动态循环的应力幅值σa与平均应力σm下的磁化规律：相同循环周次下，σa主要影响应力磁化率，σm主要影响应力饱和磁化大小；σm相同时，随着σa的增大，达到应力饱和状态的速度升高；σa相同时，随着σm的增大，应力饱和磁化强度逐渐减小。为验证J-A-N模型有效性，对45钢三点弯曲试件进行了多周期动态循环应力下的磁场信号检测实验，实验结果与模型结果一致。

关键词： J-A模型力磁耦合磁记忆检测早期疲劳损伤

维普期刊数据库博看期刊

在线全文

学校读者我要写书评

暂无评论

利用光学影像的滑坡位移监测

测绘通报 2024年第6期 41-45,64页

作者：刘卫南宋红克李清波谢谟文黄河勘测规划设计研究院有限公司河南郑州450003 水利部黄河流域水治理与水安全重点实验室(筹) 河南郑州450003 北京科技大学土木与资源工程学院北京100083

为充分挖掘光学遥感图像在滑坡监测中的应用潜力,本文基于数字图像相关法推导了适应滑坡非均匀形变和自然光照影响的滑坡位移光学影像计算公式,形成了基于光学影像的滑坡位移监测方法。试验分析了地表形变方式和形变量对滑坡位移光学影... 详细信息

为充分挖掘光学遥感图像在滑坡监测中的应用潜力,本文基于数字图像相关法推导了适应滑坡非均匀形变和自然光照影响的滑坡位移光学影像计算公式,形成了基于光学影像的滑坡位移监测方法。试验分析了地表形变方式和形变量对滑坡位移光学影像计算公式的影响,给出了地表平移、旋转、扭曲3种不同形变方式下,计算误差的概率累计值变化曲线,证明了该公式95%计算结果的相对误差在0.04以内;利用两期SkySat卫星光学影像计算了某滑坡的平面位移场,分析了该滑坡的表面形变特征。本文研究为滑坡灾害监测预警提供了新的技术参考。

关键词：滑坡监测数字图像相关光学影像遥感

半胱氨酸协同Fe(Ⅲ)活化过一硫酸盐降解氧氟沙星的效果和机制

在线全文

学校读者我要写书评

暂无评论

环境科学学报 2024年第8期44卷 250-258页

作者：张海洋汪黎东刘玮男李贞华北电力大学环境科学与工程学院北京102206

Fe(Ⅱ)活化过一硫酸盐(PMS)的高级氧化工艺可以有效地降解有机污染物,但Fe(Ⅲ)向Fe(Ⅱ)转化的缓慢速率严重抑制了其广泛应用.在这项研究中,发现将天然氨基酸半胱氨酸(Cys)加入到Fe(Ⅲ)/PMS体系中,可以加速Fe(Ⅲ)还原为Fe(Ⅱ),增强体系... 详细信息

Fe(Ⅱ)活化过一硫酸盐(PMS)的高级氧化工艺可以有效地降解有机污染物,但Fe(Ⅲ)向Fe(Ⅱ)转化的缓慢速率严重抑制了其广泛应用.在这项研究中,发现将天然氨基酸半胱氨酸(Cys)加入到Fe(Ⅲ)/PMS体系中,可以加速Fe(Ⅲ)还原为Fe(Ⅱ),增强体系对氧氟沙星(OFX)的降解.同时,在Cys/Fe(Ⅲ)/PMS体系中,除了活性物质·OH、SO_(4)^(·-)、^(1)O_(2)外,还鉴定出了Fe(Ⅳ),证实OFX的降解是自由基与非自由基协同作用的结果,并且探讨了Cys/Fe(Ⅲ)/PMS体系中可能存在的催化机制,研究了阴离子(Cl^(-)、HCO_(3)^(-)、HPO_(4)^(2-))对体系降解效率的影响,为Fe(Ⅲ)/PMS体系的应用及抗生素废水的处理提供了新思路.

关键词：过一硫酸盐半胱氨酸 Fe(Ⅲ) 氧氟沙星高级氧化

在线全文

学校读者我要写书评

暂无评论

金属磁记忆检测的关键技术研究现状与展望

压力容器 2024年第1期41卷 70-82页

作者：邢海燕段成凯刘长皓徐成刘伟男刘传东北石油大学机械科学与工程学院黑龙江大庆163318

金属磁记忆检测技术是一种绿色无污染、可检出早期应力集中、隐性损伤以及宏观缺陷的全寿命无损检测技术,经过20多年发展,已取得众多研究成果并应用于压力容器、石油管道、铁路桥梁、能源电力、航空航天等重要领域。针对金属磁记忆检测... 详细信息

金属磁记忆检测技术是一种绿色无污染、可检出早期应力集中、隐性损伤以及宏观缺陷的全寿命无损检测技术,经过20多年发展,已取得众多研究成果并应用于压力容器、石油管道、铁路桥梁、能源电力、航空航天等重要领域。针对金属磁记忆检测技术近年来的热点与难点问题,从理论基础到工程应用中的关键技术出发,归纳总结了磁记忆检测技术的机理、信号降噪与特征提取,以及机器学习在磁记忆检测评价中的应用等方面的研究现状,并对磁记忆检测技术亟待解决的关键难点问题与未来发展方向进行了探讨。

关键词：磁记忆机理信号降噪特征提取定量评价机器学习

Retrieval of the effective constitutive parameters from metamaterial absorbers

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第11期30卷 590-596页

作者： Shaomei Shi Xiaojing Qiao Shuo liu weinan liu School of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China

The equivalent medium theory of metamaterials provides a way to obtain their effective constitutive ***,because of its non-reciprocity,the complexity of the electromagnetic coupling,and a metallic bottom layer,it has been challenging to retrieve them from a metamaterial *** this paper,we propose a method without any approximation to obtain them,in which the non-reciprocity and the strong electromagnetic coupling are *** with the three methods such as symmetric metamaterial method,asymmetric metamaterial method and metasurface method,our method can reveal the metamaterial absorber’s electrical and magnetic resonance and show its electromagnetic coupling *** deal with a metamaterial absorber with a metallic bottom layer,four corners of the metallic bottom layer in the unit cell are removed,making it possible to retrieve the electromagnetic ***,these results show that the metamaterial absorber with a metallic bottom layer in our example operates in a negative refraction state at the half absorption frequencies,which helps further understand the absorbing mechanism of these metamaterial absorbers.

关键词： effective constitutive parameters metamaterial absorber negative refraction

Comparison of 2-acetylfuran,2-ethylfuran,and 2-methylfuran spherically expanding flame intrinsic instabilities

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2022年第10期65卷 2388-2398页

作者： XU CangSu WANG QianWen LI XiaoLu OPPONG Francis liu weinan College of Energy Engineering State Key Laboratory of Clean Energy UtilizationZhejiang UniversityHangzhou 310027China College of Mechanical and Electrical Engineering Key Laboratory of Intelligent Manufacturing Quality Big Data Tracing and Analysis of Zhejiang ProvinceChina Jiliang UniversityHangzhou 310018China

The intrinsic instability of three furan derivatives, namely, 2-acetylfuran(AF), 2-ethylfuran(EF), and 2-methylfuran(MF), is experimentally and theoretically investigated and compared. A deep-learning-based end-to-end system is used to segment the cells and measure the crack length on the cellular flame front of the spherically expanding flame to quantitively investigate the flame morphology. Moreover, the flame front radius profile is quantitively investigated to shed light on the correlation between disturbance amplitude and flame radius. With the use of the linear stability model, the theoretical critical flame radius and Peclet number are obtained and compared to their corresponding experimental results to characterize the outset of cellularization and evaluate the flame instability propensity. Our analysis shows that compared with AF and EF, MF is prone to cellularization at a smaller flame radius and has a faster cell proliferation rate and crack length growth rate before reaching the hydrodynamic saturation limit. Meanwhile, the average area of saturated cells tends to be similar for the three furan derivatives. Furthermore,AF premixed flame does not exhibit cellularization before the flame radius is less than 45 mm in low initial pressure.

关键词： furan derivatives spherical expanding flame flame intrinsic instability linear stability theory

“职业教育走出去”背景下高职院校英文校名分析与思考

在线全文

学校读者我要写书评

暂无评论

宁波职业技术学院学报 2024年第4期28卷 24-29页

作者：柳伟男石佳文陈伟东杭州职业技术学院浙江杭州310018

校名是高职院校整体形象的重要表现形式,具有十分重要的品牌价值。中国职业教育走向世界,高职院校的英文校名在国际诸多场合不断出现。以56所高水平学校建设单位为例,分析它们英文校名的使用情况,发现四种常用的表达形式。进一步对英文... 详细信息

校名是高职院校整体形象的重要表现形式,具有十分重要的品牌价值。中国职业教育走向世界,高职院校的英文校名在国际诸多场合不断出现。以56所高水平学校建设单位为例,分析它们英文校名的使用情况,发现四种常用的表达形式。进一步对英文校名的表达释义、在国际互联网上的使用情况和科技创新领域的使用情况进行分析,并从三个方面分析了英文校名的特征及影响,旨在为我国高职院校后续升为职教本科院校优化英文校名时提供现实依据和理论数据支持,助力中国职业教育走向世界。

关键词：高职院校英文校名 “双高”建设职业技术教育本科层次职业教育

Tanshinone IIa antagonizes spinal ischemia/reperfusion injury by interfering with upstream glutamic acid factors

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2010年第20期5卷 1573-1577页

作者： Li Zhang Xiang Lin weinan liu Jianhua Lin School of Traumatology and Orthopedics Fujian University of Traditional Chinese Medicine Fuzhou 350108 Fujian Province China Department of Traumatology and Orthopedics People's Hospital of Fujian University of Traditional Chinese Medicine Fuzhou 350004 Fujian Province China Department of Orthopedics First Affiliated Hospital of Fujian Medical University Fuzhou 350005 Fujian Province China

Based on the hypothesis that upstream factor inhibition results in better treatment effects than downstream factor inhibition,the present study interfered with glutamic acid（Glu）-released upstream factors,such as Glu transporter function and Na＋-K＋-adenosine triphosphatases（ATPase）activity *** with spinal cord ischemia/reperfusion injury received intraperitoneal injections of tanshinone Ila and Glu uptake and Na＋-K＋-ATPase activity were *** showed that tanshinone Ila influenced Glu-released upstream factors following spinal ischemia/reperfusion injury and protected against spinal ischemia/reperfusion injury.

关键词： spinal cord ischemia/reperfusion injury tanshinone glutamic acid transporter Na+-K+-ATPase neural regeneration

Total organic carbon content logging prediction based on machine learning:A brief review

在线全文

学校读者我要写书评

暂无评论

能源地球科学(英文)

能源地球科学(英文) 2023年第2期4卷 100-107页

作者： Linqi Zhu Xueqing Zhou weinan liu Zheng Kong Institute of Deep-sea Science and Engineering Chinese Academy of SciencesSanyaHainan572000China Southern Marine Science and Engineering Guangdong Laboratory Zhuhai ZhuhaiGuangdong519000China CNOOC China Limited LtdShenzhen BranchShenzhen518054China Exploration and Development Research Institute Shengli Oilfield CompanySINOPECDongyingShandong257029China

The total organic carbon content usually determines the hydrocarbon generation potential of a formation.A higher total organic carbon content often corresponds to a greater possibility of generating large amounts of oil or ***,accurately calculating the total organic carbon content in a formation is very *** research is focused on precisely calculating the total organic carbon content based on machine *** present,many machine learning methods,including backpropagation neural networks,support vector regression,random forests,extreme learning machines,and deep learning,are employed to evaluate the total organic carbon ***,the principles and perspectives of various machine learning algorithms are quite *** paper reviews the application of various machine learning algorithms to deal with total organic carbon content evaluation *** various machine learning algorithms used for TOC content predication,two algorithms,the backpropagation neural network and support vector regression are the most commonly used,and the backpropagation neural network is sometimes combined with many other algorithms to achieve better ***,combining multiple algorithms or using deep learning to increase the number of network layers can further improve the total organic carbon content *** prediction by backpropagation neural network may be better than that by support vector regression;nevertheless,using any type of machine learning algorithm improves the total organic carbon content prediction in a given research *** to some published literature,the determination coefficient(R^(2))can be increased by up to 0.46 after using machine *** learning algorithms may be the next breakthrough direction that can significantly improve the prediction of the total organic carbon *** the total organic carbon content based on machine learning is of great significance.

关键词： Total organic carbon content Well logging Machine learning Backpropagation neural network Support vector regression