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

矿井工作环境热舒适性的影响

湖南科技大学学报（自然科学版） 2024年第2期39卷 17-24页

作者：毛聪游波周超刘剑锋杨娇湖南科技大学资源环境与安全工程学院湖南湘潭411201 国家电投五凌电力有限公司湖南长沙410004

热舒适性是影响矿工的工作效率和身心健康的重要因素.基于热平衡原理和二节点热生理模型,对矿井工作环境热舒适性的影响因素进行理论分析,采用预计平均热感觉指数(Predicted Mean Vote, PMV)、预计不满意率(Predicted Percent Dissatisf... 详细信息

热舒适性是影响矿工的工作效率和身心健康的重要因素.基于热平衡原理和二节点热生理模型,对矿井工作环境热舒适性的影响因素进行理论分析,采用预计平均热感觉指数(Predicted Mean Vote, PMV)、预计不满意率(Predicted Percent Dissatisfied, PPD)、标准有效温度(Standard Effective Temperature, SET)指标来评价矿井工作环境热舒适性.结果表明:在矿井工作环境中,当温度为24~28℃,空气的相对湿度为50%~80%,送风速度为0.2~0.4 m/s时,可以满足人体对热舒适性的要求;当送风速度偏高时,适当提高相对湿度和增加温度能满足PMV,PPD指标对热舒适性的要求;劳动强度严重影响热舒适性.利用数值模拟的方法进一步研究温度与送风速度共同作用的影响,探究不同位置的温度与送风速度的差异,为改善工作环境热舒适性提供重要依据.

关键词：热舒适性评价指标数值模拟温度场速度场

在线全文

学校读者我要写书评

暂无评论

杂原子掺杂碳基氧还原催化剂研究进展

现代化工 2024年第6期44卷 25-29页

作者：黄媚佳胡茂从姚振华江汉大学光电材料与技术学院湖北武汉430056

系统介绍了各种杂原子掺杂碳基催化剂(包括单原子掺杂、两元掺杂、三元掺杂)以及掺杂金属的碳基催化剂的研究进展,并对其发展前景和难点进行了展望和分析,可为碳基氧还原催化剂的进一步研究提供参考。

关键词：掺杂碳材料氧还原反应催化剂燃料电池

High-precision deformation monitoring algorithm for GBSAR system: rail determination phase error compensation

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2016年第8期59卷 204-219页

作者： Cheng HU mao ZHU Tao ZENG Weiming TIAN cong mao Beijing Key Laboratory of Embedded Real-time Information Processing Technology Beijing Institute of Technology

In recent years, the repeat-pass GBSAR(ground based synthetic aperture radar) system has demonstrated its capacity to acquire deformation. Nevertheless, in a variety of applications, it needs to measure the deformation with the precision up to 0.1 mm, which could not be reached by utilizing the traditional PS(permanent scatterer) algorithm in most cases. Generally, one of the main reasons could be summarized into the phase error caused by the rail determination error, because the precision of rail determination might degrade during long working hours. However, the traditional PS algorithm could not compensate for the phase error caused by the rail determination error. In order to solve the problems, we modify the conventional PS ***, we deduced the transformation relationship between the rail determination error and its corresponding interferometric phase error. Then, the phase errors caused by the atmosphere and the rail determination error were jointly compensated. The experimental data, which were obtained in Fangshan District in Beijing(China), were used to test and verify the performance of the new algorithm. After the comparison between the results processed by the new algorithm and those processed by the traditional algorithm, the proposed method demonstrated its ability to obtain high-precision deformation.

关键词： permanent scatterer(PS) synthetic aperture radar(SAR) ground-based SAR deformation monitoring radar

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

高熵合金催化剂的制备方法及其应用

现代化工 2024年第1期44卷 44-47,53页

作者：胡庆姚振华胡茂从孙玉澄江汉大学光电材料与技术学院湖北武汉430056 中国合格评定国家认可中心北京100062

系统介绍了高熵合金的制备方法,包括脱合金法､机械合金法､热还原法及其他方法,评述了高熵合金催化剂在电催化析氢反应､析氧反应及氧还原反应中的应用,提出了目前面临的问题并进行了展望。

关键词：高熵合金催化剂制备方法应用

Grating lobes suppression method for stepped frequency GB-SAR system

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2014年第6期25卷 987-995页

作者： Tao Zeng cong mao Cheng Hu mao Zhu Weiming Tian Jingjing Ren School of Information and Electronics Beijing Institute of Technology China Academy of Space Technology (CAST)

A grating lobes suppression method for chirp-subpulse stepped frequency（CSSF） signals is proposed, which is applied to deformation monitoring using the ground based synthetic aperture radar（GB-SAR） system. This method is based on accurate estimation and correction of the phase and amplitude error along two dimensions（range and azimuth）, i.e., the error estimation inside the subpulse（in-subpulse error） and across the stepped frequency subpulses（cross-subpulse error） of transmitted CSSF signals. Validated both with simulated data and experimental data recorded in the deformation monitoring campaign, it can be seen that the method as well as the relative conclusions can be fully and effectively applied to most of the stepped frequency systems.

关键词： chirp-subpulse stepped frequency signal(CSSF) sup-pression of grating lobes ground based synthetic aperture radar differential interferometer SAR error analysis

Cutting Behavior of Cortical Bone in Different Bone Osteon Cutting Angles and Depths of Cut

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2022年第3期35卷 80-91页

作者： Yuanqiang Luo Yinghui Ren Yang Shu cong mao Zhixiong Zhou Z.M.Bi College of Mechanical and Vehicle Engineering Hunan UniversityChangsha 410082China Hunan Provincial Key Laboratory of Intelligent Manufacturing Technology for High-performance Mechanical Equipment Changsha University of Science and TechnologyChangsha 410114China Department of Civil and Mechanical Engineering Purdue University Fort WayneFort WayneIN 46805USA

Cortical bone is semi-brittle and anisotropic,that brings a challenge to suppress vibration and avoid undesired fracture in precise cutting process in *** this paper,a novel analytical model is proposed to represent cortical bone cutting *** model is utilized to predict the chip formations,material removal behavior and cracks propagation under varying bone osteon cutting angles and *** of orthogonal cutting experiments were conducted on cortical bone to investigate the impact of bone osteon cutting angle and depth of cut on cutting force,crack initialization and *** observed chip morphology highly agreed with the prediction of chip formation based on the analytical *** curly,serrated,grainy and powdery chips formed when the cutting angle was set as 0°,60°,90°,and 120°,*** bone were removed dominantly by shearing at a small depth of cut from 10 to 50μm,and by a mixture of pealing,shearing,fracture and crushing at a large depth of cut over 100μm at different bone osteon ***,its fracture toughness was calculated based on measured cutting *** is found that the fluctuation of cutting force is suppressed and the bone material becomes easy to remove,which attributes to lower fracture toughness at bone osteon cutting angle 0°.When the cutting direction develops a certain angle to bone osteon,the fracture toughness increases then the crack propagation is inhibited to some extent and the fluctuation of cutting force comparatively *** is a theoretical and practical significance for tools design and operational parameters choice in surgeries.

关键词： Bone cutting surgery Orthogonal cutting models Anisotropic materials Chip formation Crack initialization and propagation Fracture toughness

Material Removal Characteristics of Single-Crystal 4H-SiC Based on Varied-Load Nanoscratch Tests

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2023年第4期36卷 125-138页

作者： Kun Tang Wangping Ou cong mao Jie Liang Moke Zhang Mingjun Zhang Yongle Hu Hunan Provincial Key Laboratory of Intelligent Manufacturing Technology for High-performance Mechanical Equipment Changsha University of Science and TechnologyChangsha 410114China

Single-crystal silicon carbide(SiC)has been widely applied in the military and civil fields because of its excellent physical and chemical ***,as is typical in hard-to-machine materials,the good mechanical properties result in surface defects and subsurface damage during precision or ultraprecision *** this study,single-and double-varied-load nanoscratch tests were systematically performed on single-crystal 4H-SiC using a nanoindenter system with a Berkovich *** material removal characteristics and cracks under different planes,indenter directions,normal loading rates,and scratch intervals were analyzed using SEM,FIB,and a 3D profilometer,and the mechanisms of material removal and crack propagation were *** results showed that the Si-plane of the single-crystal 4H-SiC and edge forward indenter direction are most suitable for material removal and *** normal loading rate had little effect on the scratch depth,but a lower loading rate increased the ductile region and critical depth of ***,the crack interaction and fluctuation of the depth-distance curves of the second scratch weakened with an increase in the scratch interval,the status of scratches and chips changed,and the comprehensive effects of the propagation and interaction of the three cracks resulted in material fractures and chip *** calculated and experimental values of the median crack depth also showed good consistency and ***,this study provides an important reference for the high-efficiency and precision machining of single-crystal SiC to ensure high accuracy and a long service life.

关键词： Single crystal silicon carbides Varied-load nanoscratch Material removal Crack propagation

42CrMo钢精密切削的刀具磨损量预测研究

在线全文

学校读者我要写书评

暂无评论

工具技术 2024年第3期58卷 138-143页

作者：成钢唐昆刘庞中刘子聪袁剑平胡永乐毛聪江麓机电集团有限公司长沙理工大学机械装备高性能智能制造关键技术湖南省重点实验室

针对42CrMo钢精密切削刀具磨损量预测研究小样本、非线性的特点,将量子粒子群算法(QPSO)、卷积神经网络(CNN)及长短期神经网络(LSTM)相结合,构建了QPSO-CNN-LSTM组合预测模型。采用QPSO算法对CNN-LSTM模型的隐藏层单元数、学习率、卷积... 详细信息

针对42CrMo钢精密切削刀具磨损量预测研究小样本、非线性的特点,将量子粒子群算法(QPSO)、卷积神经网络(CNN)及长短期神经网络(LSTM)相结合,构建了QPSO-CNN-LSTM组合预测模型。采用QPSO算法对CNN-LSTM模型的隐藏层单元数、学习率、卷积核等进行优化,结合CNN网络特征提取能力强、LSTM网络具备记忆能力的特点,对实际加工实验的刀具磨损量进行预测,并通过误差评价指标分析,与CNN、LSTM、BP等单一模型以及PSO-GRNN组合模型进行预测效果对比研究。研究结果表明,本文构建的组合预测模型相对于单一预测模型,其预测值与真实值吻合程度更高;相对于PSO-GRNN组合模型,三种误差评价指标的误差值至少降低了27%,其泛化性和稳定性较好,预测精度与非线性拟合能力更强。

关键词：刀具磨损量组合预测模型量子粒子群算法优化卷积神经网络长短期神经网络

Effect of laser-discrete-quenching on bonding properties of electroplated grinding wheel with AISI 1045 steel substrate and nickel bond

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2021年第6期34卷 79-89页

作者： cong mao Peihao CAI Yongle HU Yujie ZHONG Jishuang WEI Zhuming BI Yifeng JIANG Linfeng XIAO Mingjun ZHANG College of Automotive and Mechanical Engineering Changsha UniversityCollege of Automotive and Mechanical EngineeringChangsha University of Science and TechnologyChangsha 410114China Hunan Provincial Key Laboratory of Intelligent Manufacturing Technology for High performance Mechanical Equipment Changsha University of Science and TechnologyChangsha 410114China Department of Civil and Mechanical Engineering Purdue University Fort WayneFort WayneIN 46805USA

To improve the bonding strength between the nickel bond and the hub of the electroplated diamond grinding wheel,a hybrid technique was proposed to combine laser prequenching steel substrate and post-electroplating *** validate the effectiveness of the proposed technique,AISI 1045 substrate was *** bonding properties between the electroplated nickel coating and substrate with or without laser-discrete-quenching were discussed comparatively by scratch,indentation,and thermal shock *** results show that the prequenching treatment leads to phase transformation of AISI 1045 microstructure from the mixed pearlite and ferrite phases into the martensitic *** the martensitic phase is characterized as a high corrosion resistance,the interface of substrate/coating is smooth and flat in the prequenched zone,and the coating is bonded well with the steel *** contrast to the steel substrate without pre-quenching treatment,the proposed technique significantly enhanced the bonding strengths of the electroplated *** one hand,the average hardness of electroplated nickel-coating on the laser pre-quenched zone is increased by 18.7%,and the scratch depth with the same load become narrower and *** the other hand,the coefficient of friction(CoF)and the vibration amplitude are reduced,and the coating is bonded effectively with the substrate to inhibit the crack initialization at the *** prevents effectively the coating from peeling off and improves significantly the thermal shock resistance property.

关键词： Laser-discrete-quenching Bonding properties Electroplated grinding wheel AISI 1045 substrate Nickel coating