检索结果-南通市图书馆

Laboratory investigation of coal sample permeability under the coupled effect of temperature and stress

Frontiers of Earth Science 2022年第4期16卷 963-974页

作者： Yina YU Zhaoping MENG jiangjiang li Yixin LU Caixia GAO College of Geosciences and Surveying Engineering China University of Mining and Technology(Beijing)Beijing 100083China State Key Laboratory of Coal and CBM Co-mining Jincheng 048000China Exploration and Development Research Institute PetroChina Huabei Oilfield CompanyRenqiu 062552China

The stress and temperature sensitivities of coal reservoirs are critical geological factors affectingcoalbed methane(CBM)well exploitation;in particular it is important to reduce or eliminate their influence on coal reservoir *** investigate coal permeability behavior at various effective stresses and temperatures,CH4 permeability tests were conducted on raw coal samples under a varying effective stress of 2.0-8.0 MPa under five different temperatures(25℃-65℃)in the *** results show that the permeability of the coal samples exponentially decreases with increasing effective stress or temperature,which indicates obvious stress and temperature *** a dimension-less treatment of coal permeability,effective stress,and temperature,a new stress sensitivity index S and tempera-ture index ST are proposed to evaluate coal stress and temperature sensitivity evaluation *** new parameters exhibit integrality and uniqueness,and,in combination with stress sensitivity coefficient αk,tempe-rature sensitivity coefficient αT,and the permeability damage rate PDR,the sensitivities of coal permeability to stress and temperature are *** results indicate that coal sample stress sensitivity decreases with increasing effective stress,while it first decreases and then increases with increasing ***,coal sample temperature sensitivity shows a downward trend when temperature increases and fluctuates when effective stress ***,a coupled coal permeability model considering the impacts of effective stress and temperature is established,and the main factors affecting coal reservoir permeability and their control mechanism are *** results can provide some theoretical guidance for the further development of deep CBM.

关键词： deep coal reservoir permeability variation stress sensitivity temperature sensitivity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Different structural origins for different sized surface pits observed on a-plane GaN film

引用

Science China(Technological Sciences) 2016年第1期59卷 156-161页

作者： GAO ZhiYuan li jiangjiang XUE XiaoWei CUI BiFeng XING YanHui ZOU DeShu Microelectronic School Beijing University of Technology

A correlation study between the observed surface morphology using high-resolution scanning electron microscopy(HRSEM) and the observed structural imperfections using transmission electron microscopy(TEM) has been conducted for a-plane Ga N. There are three different sized asymmetric surface pits: large pit of 500 nm–2 ?m in side length, medium pit of 50 nm in side length, and small pit with side lengths of less than 5 nm, which originate from incomplete island coalescence, screw dislocation, and partial dislocation(PD), respectively. Both screw dislocation and PD can produce pits on the free surface because they have a perpendicular line tension to the surface, which must remain in balance with the surface tension. The two types of dislocation lead to distinctive pit sizes because the PD has a smaller Burgers vector component along the dislocation line than the pure screw dislocation. A pit that is produced in the island-coalescing process is much larger than those caused by dislocations because island coalescence is a kinetic process that involves large-scale mass transportation, whereas the dislocation mediates the surface in the local area. These three types of surface pits sometimes interact with one another in space. The coalescence of the island determines the surface morphology at large scales, whereas the defects affect the details.

关键词： surface pits nonpolar Ga N screw dislocations partial dislocations Island coalescence

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Prediction of Disease Transmission Risk in Universities Based on SEIR and Multi-hidden Layer Back-propagation Neural Network Model

IJLAI Transactions on Science and Engineering

引用

IJLAI Transactions on Science and Engineering 2024年第1期2卷 24-31页

作者： jiangjiang li lijuan Feng School of Electronic and Electrical Engineering Zhengzhou University of Science and TechnologyZhengzhou 450064 China

Against the background of regular epidemic prevention and control,in order to ensure the return of teachers to work,students to return to school and safe operation of schools,the risk of disease transmission is analyzed in key areas such as university canoons,auditoriums,teaching buildings and *** risk model of epidemic transmission in key regions of universities is established based on the improved SEIR model,considering the four groups of people,namely susceptible,latent,infected and displaced,and their mutual transformation *** feature post-processing,the selected feature parameters are processed with monotone non-decreasing and smoothing,and used as noise-free samples of stacked sparse denoising automatic coding network to train the ***,the feature vectors after dimensionality reduction of the stacked sparse denoising automatic coding network are used as the input of the multi-hidden layer back-propagation neural network,and these features are used as tags to carry out fitting training for the *** results show that the implementation of control measures can reduce the number of contacts between infected people and susceptible people,reduce the transmission rate of single contact,and reduce the peak number of infected people and latent people by 61%and 72%respectively,effectively controlling the disease spread in key regions of *** method is able to accurately predict the number of infections.

关键词： Disease transmission SEIR model Prediction Stacked sparse denoising automatic coding network

来源：

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

Key Technologies of Image Fusion Based on Deep Learning:A Survey

IJLAI Transactions on Science and Engineering

引用

IJLAI Transactions on Science and Engineering 2024年第3期2卷 81-90页

作者： lijuan Feng jiangjiang li School of Electronics and Electrical Engineering Zhengzhou University of Science and Technology Zhengzhou 450064 China

Image fusion is an important branch of image *** of the remarkable advantages of neural network in image feature extraction and classification,the application of neural network technology in the field of image fusion is also a research hotspot in recent ***,the infrared and visible light image fusion algorithms based on shallow and deep neural networks are summarized,and the research progress of image fusion technology is introduced in detail,and the research results of fusion algorithms are ***,the challenges faced by image fusion are discussed,and the future development direction of this field is forecasted.

关键词： Image fusion Deep learning Deep neural networks

来源：

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

Study on the Student Concentration in Class Based on Deep Multitasking Learning Framework

IJLAI Transactions on Science and Engineering

引用

IJLAI Transactions on Science and Engineering 2024年第3期2卷 47-57页

作者： jiangjiang li lijuan Feng Jiaxiang Wang School of Electronic and Electrical Engineering Zhengzhou University of Science and Technology Zhengzhou 450064 China

In order to solve the problem of poor teaching quality caused by classroom teachers’inability to grasp students’dynamics in time,this paper designs a feedback system for classroom attention with the help of the research on expression recognition technology in deep *** the real-time analysis of expression,although the deeper deep learning network has more accurate recognition effect,there are drawbacks of too large model and too many parameters in the network training *** this paper,we propose a student concentration algorithm that uses the Convolutional Block attentional module(CBAM)and the Local Binary Pattern(LBP)to reduce the number of parameters in the model by replacing the convolution with the depthseparable convolution LBP preprocessing enhances the feature validity of the input feature map and improves the training speed and accuracy of the *** experimental results show that the algorithm has a good discriminating effect on expression recognition,and the model is small.

关键词： Student concentration CBAM Local Binary Pattern Deep learning

来源：

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

Sensor Principle and Application Course Ideological and Political Teaching Reform

IJLAI Transactions on Science and Engineering

引用

IJLAI Transactions on Science and Engineering 2024年第4期2卷 58-64页

作者： Qingmin Song jiangjiang li lijuan Feng Xianan Song Zhenkun liu School of Electronics and Electrical Engineering Zhengzhou University of Science and Technology 450064 Zhengzhou China

“Sensor Principle and Application”is a compulsory professional course for Internet of Things engineering,electronic information engineering,intelligent perception and other *** view of the pain points existing in the teaching of this course,a series of innovative measures are put forward:integrating and updating the teaching content,adopting mixed teaching mode and innovative experimental methods,digging deeply into the curriculum ideology and politics,and building a multiple assessment and evaluation system,so as to comprehensively improve the learning effect of students and enhance their practical innovation ability and comprehensive *** order to promote the ideological and political teaching reform of the sensor Principle and application course,the research group combined the training requirements of engineering certification for students and the characteristics of application-oriented undergraduate students,with education moral education as the fundamental goal and task,to cultivate students’sense of innovation and feelings of home and country as the starting point,clear teaching objectives,use a variety of teaching methods,fully tap the integration point of moral education in the course,and optimize the assessment *** ideological and political construction of professional courses will stimulate young students’confidence in the system,theory,road and culture to a greater extent,and train students to become application-oriented technical talents who love the Party,love the country and dare to innovate.

关键词： Sensor principle and application Internet of Things electronic information engineering

来源：

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

Microfluidic systems with chemiluminescence and fluorescence as detectors and their application to the analysis

Microfluidic systems with chemiluminescence and fluorescence...

引用

30th International Symposium on Capillary Chromatography、4th GC×GC Symposium、16th National Symposium and Exhibition on Chromatography,i.e. 1st Dalian International Symposium and Exhibition on Chromatography

作者： Jin-Ming lin~* Haifang li jiangjiang liu Department of Chemistry Tsinghua University Beijing 100084 China

＜正＞Due to the simple optical devices,wide linear range of responding signal and many well characters of chemiluminescence（CL）and fluorescence（FL）systems,CL and FL are uniquely suited to on-line detection for miniaturized total analysis system（μ-TAS）[1].In our recent research work,some microchips with CL or FL as detector were designed and applied for the different applications.A single-channel poly（dimethylsiloxane）（PDMS）mieroehip was developed for the monitoring and kinetics studies of single particle[2].The mieroehannel consisting of a narrow section following to a relatively wide part enabled particle introduction, transfer and location.A microinfusion pump was employed to delivery eluting solution in precise *** the particle contacted with eluting solution,the solute transferred from particle into eluting and would be detected by laser-induced fluorescence or chemiluminescence *** process of single particle was high sensitively monitored with highly *** on desorption curves obtained,kinetics studies were *** sediments desorption process of single resin particles and single active carbon particles were *** applications of CL and FL in micrichips will also be introduced.

关键词： Microfluidic chip Chemiluminescence Fluorescence

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

汽车支架的差压铸造工艺优化

引用

热加工工艺 2021年第19期50卷 71-74页

作者：李江江张希通天津职业大学天津300410 天津职业技术师范大学天津300222

进行了汽车支架用A356铝合金的差压铸造成型,并进行了不同浇注温度、充型压力和结晶增压压力下的力学性能测试、比较和分析。结果表明:随浇注温度、充型压力和结晶增压压力的增加,抗拉强度先增大后减小,断后伸长率反之。在720℃浇注温度... 详细信息

进行了汽车支架用A356铝合金的差压铸造成型,并进行了不同浇注温度、充型压力和结晶增压压力下的力学性能测试、比较和分析。结果表明:随浇注温度、充型压力和结晶增压压力的增加,抗拉强度先增大后减小,断后伸长率反之。在720℃浇注温度、40 kPa充型压力、5 kPa结晶增压压力下,试样的抗拉强度为峰值(302 MPa)、断后伸长率为最小值(3.5%)。汽车支架用A356铝合金的浇注温度优选为720℃、充型压力优选为40 kPa、结晶增压压力优选为5 kPa。

关键词：汽车支架 A356铝合金差压铸造力学性能

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于逻辑分析法的本田自动变速器电液控制策略分析

引用

机床与液压 2010年第22期38卷 121-122页

作者：李江江尤明福李志坡天津职业技术师范大学天津300222 石家庄铁道大学河北石家庄050043

运用逻辑分析法分析油路的走向和电磁阀的控制状态,将错综复杂的换挡油路过程简化为基本的逻辑表达过程,使得换挡过程更清晰,并用逻辑法表达自动变速器的油路走向过程。

关键词：自动变速器逻辑分析法电液控制

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

单相级联七电平逆变器拓扑结构及其控制方法

引用

电工技术学报 2019年第18期34卷 3843-3853页

作者：张琦李江江孙向东安少亮西安理工大学自动化与信息工程学院西安710048 西安理工大学陕西复杂系统控制与智能信息处理重点实验室西安710048

针对传统多电平逆变器结构复杂等问题,提出一种单相级联七电平逆变器拓扑及其控制方式。该逆变器由三电平Boost电路和六开关逆变电路构成,利用三电平Boost电路调节中点电位,使得中间母线电容电压占比为1∶2,为实现七电平输出提供电位条... 详细信息

针对传统多电平逆变器结构复杂等问题,提出一种单相级联七电平逆变器拓扑及其控制方式。该逆变器由三电平Boost电路和六开关逆变电路构成,利用三电平Boost电路调节中点电位,使得中间母线电容电压占比为1∶2,为实现七电平输出提供电位条件。相对于传统多电平拓扑,该拓扑使用较少的开关器件,简化了电路结构。由于中间母线电容电压控制效果是系统可靠运行的关键,所以在讨论电路拓扑的运行机理的基础上,建立直流侧电压控制系统数学模型,并据此提出一种电压控制方法,从而实现逆变器控制系统的有效运行。最后,借助系统仿真与实验验证了所提电路拓扑的可行性以及理论分析的正确性。

关键词：七电平逆变器三电平 Boost 电压偏差电流前馈

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：