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Practical Method of Conical Cam Outline Expansion

Chinese Journal of Mechanical Engineering 2011年第1期24卷 127-132页

作者： chen junhua XIN Yong Institute of Mechanical and Electrical Engineering Nanchang University Nanchang 330029 China Ningbo Institute of Technology Zhejiang University Ningbo 315100 China

Conical cam mechanism has been widely used in modern machinery and ***,the commonly used planar expansion methods for the design of spatial cam contour produce significant errors,because these methods incorrectly use the distance from the axis of the follower to the main conical cam to replace the corresponding arc length on the conical ***,et al,used analytical methods to achieve higher accuracy,but these analytical methods have their own drawbacks since they are too complicated for practical *** the analysis of the errors created during the generation of conical cam contour using the existing expansion methods,this paper proposes to include diverge angle in the calculation of conical cam rotation angle in the equation of conical cam contour *** correction eliminates the error generated by the commonly used *** on the expression of the follower＇s 3D trajectory and the spatial geometry of conical cam,this paper has deduced the planar polar curve equation for determining polar coordinates for the curve of planar expansion ***,this paper provides an example of conical cam contour design based on sinusoidal acceleration *** to polar coordinates and the movement of curve equation function expression,this paper applies MATLAB software to solve coordinates for the cam expansion curve and uses AutoCAD software to generate conical cam expansion contour that meets the requirement of the law of *** proposed method provides a design process that is simple,intuitive and easy to master and *** also avoids the design error in the traditional methods for generating contour of conical cam with oscillating follower that requires high precision.

关键词： oscillating follower conical cam 3D expansion polar coordinates curve equation

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Design of Cylindrical Cam with Oscillating Follower Based on 3D Expansion of Planar Profile Model

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Chinese Journal of Mechanical Engineering 2009年第5期22卷 665-670页

作者： chen junhua LIN Zuan WU Yijie Ningbo Institute of Technology Zhejiang University Ningbo 315100 China Institute of Modern Manufacture Engineering Zhejiang University Hangzhou 310027 China

Cylindrical cam with oscillating follower is widely applicable and used in many mechanical devices and machines. However, a common error exists in the methods of designing planar profile for oscillating follower cylinder cam. In this study, we propose a new hypothesis to solve this design problem with the inclusion of deviation angle. On the basis of this new concept, equations for planar profile expansion and methods of calculating pressure angle are deduced by applying 3D expansion formula of the follower＇s motion orbit. When the pressure angle is less than allowable value, the minimum base radius can be determined by using MATLAB software. Accordingly, the planar profile of oscillating follower cylinder cam is generated by CAD software. This new method is practical and can be easily adopted for the design of oscillating follower cylindrical cam with desirable accuracy. We applied the method in the design of cylindrical cam for paper feeding mechanism used in high-speed printers. We calculated the planar profile and used it to direct the NC machine for the manufacture of the groove of cylindrical cam. The improved cylindrical cam met all of the requirements of speed and accuracy demanded by high-speed printers. Therefore, our new method has been validated by practical application.

关键词： oscillating follower cylindrical cam 3D expansion pressure angle radius of base circle profile

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Effect of Cu on Microstructures of Manganese Steel by EDXA and SEM

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Journal of Materials Science & Technology 2007年第3期23卷 307-311页

作者： Xinhua chen junhua DONG Enhou HAN Wei KE Environmental Corrosion Center Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

In order to investigate the distribution of Cu and Mg, and the effect of Cu on the microstructure of steels, manganese steels containing various Cu contents were annealed at 1260, 1100 and 1000℃, respectively, for I h and subsequently cooled to room temperature in the furnace to simulate the pre-rolling anneal. The results indicate that Cu is not microscopically segregated in the annealed steels. The scanning electron microscopy （SEM） observation shows that the main microstructure consist of ferrite and pearlite; the percentage of pearlite in the steels increases with increasing Cu content. The grain size reduces with the decrease of the annealing temperature. The results of energy dispersive X-ray analysis （EDXA） suggest that Cu content in pearlite is higher than that in ferrite, demonstrating that the microstructure-segregation of Cu occurred. However, the cast specimens show that Cu content in MnS and S-rich phases is high. In addition, Cu of 0.2%-0.4% could improve the distribution of MnS and S-rich inclusions. The optimal Cu content in steels and the optimal annealing temperature between 1100-1200℃ were determined.

关键词： Manganese steels Copper-alloying Annealing Energy dispersive X-ray analysis (EDXA) Scanning electron microscopy (SEM)

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Practice and Enlightenment of Community Governance Innovation in New Urbanization Process

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学术界 2015年第4期 263-269页

作者： chen junhua Xu Yangwen School of Economics and Management Southwest Petroleum University

New urbanization urgently calls for new ideas of community ***,this paper defines the important concepts,collates and summarizes the relevant theory. This paper takes Xindu district of chengdu as an example,analyses the practice and enlightenment of community governance innovation,attempting to provide some insights into the community governance innovation in the new urbanization process.

关键词：城市化进程治理创新社区成都市 COM

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Study on Strategic Development of Petroleum Enterprises Based on AHP- SWOT Analysis

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学术界 2016年第2期 308-313页

作者： chen junhua Hu Siyun School of Economics'and Management Southwest Petroleum University Chengdu Sichuan 610000

This thesis creates an analytical model of petroleum enterprises by applying AHP(analytic hierarchy process) and SWOT analytical *** holds that the strategy for sustainable development of petroleum enterprises shall b... 详细信息

关键词： SWOT分析方法石油企业企业发展战略 AHP 可持续发展战略企业可持续发展层次分析法经济增长

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A Concurrent Security Monitoring Method for Virtualization Environments

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China Communications 2016年第1期13卷 113-123页

作者： TIAN Donghai JIA Xiaoqi chen junhua HU Changzhen Beijing Key Laboratory of Software Security Engineering Technique School of SoftwareBeijing Institute of Technology State Key Laboratory of Information Security Institute of Information EngineeringChinese Academy of Sciences Key Laboratory of IOT Application Technology of Universities in Yunnan Province Yunnan Minzu University

Recently,virtualization technologies have been widely used in *** order to monitor the security of target systems in virtualization environments,conventional methods usually put the security monitoring mechanism into the normal functionality of the target ***,these methods are either prone to be tempered by attackers or introduce considerable performance overhead for target *** address these problems,in this paper,we present a concurrent security monitoring method which decouples traditional serial mechanisms,including security event collector and analyzer,into two concurrent *** one hand,we utilize the SIM framework to deploy the event collector into the target virtual *** the other hand,we combine the virtualization technology and multi-core technology to put the event analyzer into a trusted execution *** address the synchronization problem between these two concurrent components,we make use of Lamport's ring buffer *** on the Xen hypervisor,we have implemented a prototype system named *** experimental results show that COMO can monitor the security of the target virtual machine concurrently within a little performance overhead.

关键词： security virtualization technology concurrent monitoring

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Early Chinese Shale Gas Development Policy Research--Based on the Analysis of Literature Review and Reflection

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学术界 2017年第1期 291-302页

作者： chen junhua Hu Die School of Economics and Management Southwest Petroleum University Chengdu Sichuan 610500

With the growing energy crisis,countries around the world began to look to shale gas ***'s most successful shale gas development,has now entered the stage of mass *** journals in China based on online collection of literature related to shale gas development in the early policy research as the object,analyzes the existing network as well as about the market,shale gas development,finance,technology,ecology,regulatory policy research,summarizes the existing problems in the development of shale gas in China,refine shale gas development to China early effective improvement Suggestions at four o'clock,promote the benign development of shale gas exploration in China.

关键词：页岩气开发早期文献能源危机生产阶段学术期刊监管政策

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Simple Push-Type Wave Generating Method Using Digital Rotary Valve Control

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Chinese Journal of Mechanical Engineering 2020年第1期33卷 221-231页

作者： Yi Liu Jiafei Zheng Ruiyin Song Qiaoning Xu junhua chen Fangping Huang Ningbo Institute of Technology Zhejiang UniversityNingbo 315100China Ningbo Research Institute Zhejiang UniversityNingbo 315100China Soochow University Suzhou 215000China Zhejiang University of Technology Hangzhou 310023China

The important parameters to describe waves are their amplitude and *** order to make it easier to improve wave amplitude and facilitate wave experiment,a simple push-type wave generating method using digital rotary valve control was proposed and different wave amplitudes were generated by the new *** the mathematical model of the new method had been established,numerical analysis based on the linear wave theory was carried out by means of Matlab/Simulink software tools,and experiments were conducted on the push-type wave maker to ascertain the validity of the established model and the numerical simulation *** shows that both experimental and theoretical results agree relatively well,and the plate motion frequency and amplitude of the push-type wave maker can be continuously adjusted and the various required regular waves can be *** the wave amplitude and length descends with the increasing of working frequency,the wave amplitude can be improved conveniently by setting the axial opening width of the valve and the oil supply pressure of *** wave length remains unchanged with the axial opening width and the oil supply pressure *** research indicates that different regular waves can be easily generated by the new method and the wave amplitude can be further improved in a certain plate motion frequency range.

关键词： Push-type wave maker Digital rotary valve control Mathematical modeling Wave amplitude Wave frequency

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A Practical Online Approach to Protecting Kernel Heap Buffers in Kernel Modules

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China Communications 2016年第11期13卷 143-152页

作者： Donghai Tian Xiaoqi Jia junhua chen Changzhen Hu Jingfeng Xue Beijing Key Laboratory of Software Security Engineering Technique School of SoftwareBeijing Institute of Technology Shanghai Key Laboratory of Integrated Administration Technologies for Information Security Shanghai Jiao Tong University State Key Laboratory of Information Security Institute of Information EngineeringChinese Academy of Sciences & University of Chinese Academy of Sciences Key Laboratory of IOT Application Technology of Universities in Yunnan Province Yunnan Minzu University

Heap overflow attack is one of the major memory corruption attacks that have become prevalent for decades. To defeat this attack,many protection methods are proposed in recent years. However,most of these existing methods focus on user-level heap overflow detection. Only a few methods are proposed for kernel heap protection. Moreover,all these kernel protection methods need modifying the existing OS kernel so that they may not be adopted in practice. To address this problem,we propose a lightweight virtualization-based solution that can protect the kernel heap buffers allocated for the target kernel modules. The key idea of our approach is to combine the static binary analysis and virtualization technology to trap a memory allocation operation of the target kernel module,and then add one secure canary word to the end of the allocated buffer. After that,a monitor process is launched to check the integrity of the canaries. The evaluations show that our system can detect kernel heap overflow attacks effectively with minimal performance cost.

关键词： kernel heap overflow virtualization technology kernel module

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YOLO-Banana:An Effective Grading Method for Banana Appearance Quality

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Journal of Beijing Institute of Technology 2023年第3期32卷 363-373页

作者： Dianhui Mao Xuesen Wang Yiming Liu Denghui Zhang Jianwei Wu junhua chen School of Computer Beijing Technology and Business UniversityBeijing 100048China Research Center of Information Technology Beijing Academy of Agriculture and Forestry SciencesBeijing 100097China Beijing PAIDE Science and Technology Development Co.Ltd. Beijing 100097China Institute of Standardization Theory and Strategy China National Institute of StandardizationBeijing 100088China

The increasing trend towards independent fruit packaging demands a high appearance quality of individually packed *** this paper,we propose an improved YOLOv5-based model,YOLO-Banana,to effectively grade banana appearance quality based on the number of banana defect *** to the minor and dense defects on the surface of bananas,existing detection algorithms have poor detection results and high missing *** address this,we propose a densitybased spatial clustering of applications with noise(DBSCAN)and K-means fusion clustering method that utilizes refined anchor points to obtain better initial anchor values,thereby enhancing the network’s recognition ***,the optimized progressive aggregated network(PANet)enables better multi-level feature ***,the non-maximum suppression function is replaced with a weighted non-maximum suppression(weighted NMS)function based on distance intersection over union(DIoU).Experimental results show that the model’s accuracy is improved by 2.3%compared to the original YOLOv5 network model,thereby effectively grading the banana appearance quality.

关键词： YOLOv5 banana appearance grading clustering algorithm weighted non-maximum suppression(weighted NMS) progressive aggregated network(PANet)

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