检索结果-南通市图书馆

Design and grindability assessment with cup shaped electroplated CBN wheel grinding turbine disc slots of powder metallurgy superalloy FGH96

在线全文

学校读者我要写书评

暂无评论

CHINESE JOURNAL OF AERONAUTICS 2024年第9期37卷 521-534页

作者： Li, Benkai Ding, Wenfeng Zhu, Yejun Li, Changhe zhang, yanbin Yang, Min Ma, Xiao Liu, Mingzheng Cui, Xin Qingdao Univ Technol Sch Mech Engn Qingdao 266520 Peoples R China Nanjing Univ Aeronaut & Astronaut Natl Key Lab Sci & Technol Helicopter Transmiss Nanjing 210016 Peoples R China Nanjing Agr Univ Coll Engn Nanjing 210031 Peoples R China

The machining surface integrity of aero-engine turbine disc slots has a significant impact on their fatigue life and service performance, and achieving efficiency and high-precision machining is still a great challenge. The high machining requirements of future aeroengine turbine disc slots will be difficult to satisfy using the broaching method. In addition, existing methods of slot machining face difficulties in ensuring surface integrity. This study explored a cup shaped electroplated Cubic Boron Nitride (CBN) abrasive wheel for profile grinding the turbine disc slots of FGH96 powder metallurgy superalloy. The matrix structure of the cup shaped abrasive wheel was designed and verified. A profile grinding experiment was conducted for fir-tree slots on a five-axis machining center. The accuracy and the surface integrity were analyzed. Results show that the key dimension detection results of the slots were within the allowable tolerance range. Meanwhile, an average surface roughness Ra of 0.55 lm was achieved, the residual stress was compressive, the plastic deformation layer thickness was less than 5 lm, and the hardening layer thickness was less than 20 lm. The research findings provide a new approach to machining the slots of aviation engine turbine discs and guidance for the high-quality processing of complex components. (c) 2023 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.

关键词： Profile grinding Surface integrity Cup shaped CBN abrasive wheel Turbine disc slots FGH96 OF-THE-ART SURFACE INTEGRITY DYNAMIC RECRYSTALLIZATION FATIGUE SPEED MANUFACTURE PARAMETERS MECHANISM ALLOYS TOOLS

Force model in electrostatic atomization minimum quantity lubrication milling GH4169 and performance evaluation

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

Frontiers of Mechanical Engineering 2024年第4期19卷 55-72页

作者： Min YANG Hao MA Zhonghao LI Jiachao HAO Mingzheng LIU Xin CUI yanbin zhang Zongming ZHOU Yunze LONG Changhe LI School of Mechanical and Automotive Engineering Qingdao University of TechnologyQingdao 266520China College of Physics QingdaoUniversityQingdao 266071China Hanergy Lubrication Technology Co. Ltd.Qingdao 266200China

The nickel-based high-temperature alloy GH4169 is the material of choice for manufacturing critical components in aeroengines,and electrostatic atomization minimum quantity lubrication(EMQL)milling represents a fundamental machining process for ***,the effects of electric field parameters,jet parameters,nozzle position,and milling parameters on milling performance remain unclear,which constrains the broad application of EMQL in aerospace *** study evaluated the milling performance of EMQL on nickel-based alloys using soybean oil as the lubrication *** revealed that compared with conventional pneumatic atomization MQL milling,EMQL reduced the milling force by 15.2%-15.9%,lowered the surface roughness by 30.9%-54.2%,decreased the average roughness spacing by 47.4%-58.3%,and decreased the coefficient of friction and the specific energy of cutting by 55%and 19.6%,*** optimization experiments using orthogonal arrays demonstrated that air pressure most significantly affected the milling force and specific energy of cutting,with a contribution rate of 22%,whereas voltage had the greatest effect on workpiece surface roughness,contributing 36.71%.Considering the workpiece surface morphology and the potential impact of droplet drift on environmental and health safety,the optimal parameter combination identified were a flow rate of 80 mL/h,an air pressure of 0.1 MPa,a voltage of 30 kV,a nozzle incidence angle of 35°,an elevation angle of 30°,and a target distance of 40 *** research aimed to provide technical insights for improving the surface integrity of aerospace materials that are difficult to machine during cutting operations.

关键词： electrostatic atomization MQL nickel-based alloys milling force surface roughness force model

Grindability Evaluation of Ultrasonic Assisted Grinding of Silicon Nitride Ceramic Using Minimum Quantity Lubrication Based SiO_(2)Nanofluid

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

Chinese Journal of Mechanical Engineering 2024年第2期37卷 115-136页

作者： Yusuf Suleiman Dambatta Changhe Li Mohd Sayuti Ahmed A D Sarhan Min Yang Benkai Li Anxue Chu Mingzheng Liu yanbin zhang Zafar Said Zongming Zhou School of Mechanical and Automotive Engineering Qingdao University of TechnologyQingdao 266520China Mechanical Engineering Department Ahmadu Bello UniversityZaria 810106Nigeria Mechanical Engineering Department University of Malaya50603 Kuala LumpurMalaysia Department of Mechanical Engineering King Fahd University of Petroleum&Minerals31261 DhahranSaudi Arabia State Key Laboratory of Ultra-Precision Machining Technology Department of Industrial and Systems Engineer-ingThe Hong Kong Polytechnic UniversityHong KongChina College of Engineering University of Sharjah27272 SharjahUnited Arab Emirates Hanergy(Qingdao)Lubrication Technology Co. Ltd.Qingdao 266100China

Minimum quantity Lubrication(MQL)is a sustainable lubrication system that is famous in many machining *** involve the spray of an infinitesimal amount of mist-like lubricants during machining *** MQL system is affirmed to exhibit an excellent machining performance,and it is highly *** nanofluids are understood to exhibit excellent lubricity and heat evacuation capability,compared to pure oil-based MQL *** have shown that the surface quality and amount of energy expended in the grinding operations can be reduced considerably due to the positive effect of these *** work presents an experimental study on the tribological performance of SiO_(2)nanofluid during grinding of Si_(3)N_(4)*** effect different grinding modes and lubrication systems during the grinding operation was also *** concentrations of the SiO_(2)nanofluid was manufactured using canola,corn and sunflower *** quantitative evaluation of the grinding process was done based on the amount of grinding forces,specific grinding energy,frictional coefficient,and surface *** was found that the canola oil exhibits optimal lubrication performance compared to corn oil,sunflower oil,and traditional lubrication ***,the introduction of ultrasonic vibrations with the SiO_(2)nanofluid in MQL system was found to reduce the specific grinding energy,normal grinding forces,tangential grinding forces,and surface roughness by 65%,57%,65%,and 18%***,regression analysis was used to obtain an optimum parameter *** observations from this work will aid the smooth transition towards ecofriendly and sustainable machining of engineering ceramics.

关键词： Minimum quantity lubrication(MQL) Ultrasonic assisted grinding(UAG) Eco-friendly lubricants Nanofluid Grinding Ceramic

(Si_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)V_(0.2))C高熵陶瓷的低温制备及吸波性能

在线全文

学校读者我要写书评

暂无评论

材料导报 2024年第3期38卷 42-47页

作者：张昊黄宗玥张妍彬魏剑西安建筑科技大学材料科学与工程学院西安710055

寻求具有良好耐高温及力学性能的新型陶瓷材料是吸波材料领域的研究热点之一。高熵碳化物陶瓷具有高温热稳定性及抗氧化性好等优点,但合成温度高且吸波性能研究较少,限制了其在高温吸波材料领域的应用。本工作采用熔盐法合成了多晶岩盐... 详细信息

寻求具有良好耐高温及力学性能的新型陶瓷材料是吸波材料领域的研究热点之一。高熵碳化物陶瓷具有高温热稳定性及抗氧化性好等优点,但合成温度高且吸波性能研究较少,限制了其在高温吸波材料领域的应用。本工作采用熔盐法合成了多晶岩盐晶型(Si_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)V_(0.2))C高熵碳化物陶瓷,研究了其物相组成、微观形貌及吸波特性。结果表明:随着反应温度的升高,样品的衍射峰逐渐锐化,吸波性能明显提高。当反应温度为1500℃时,3.72 GHz时最低反射损耗达-34.68 dB;与已报道的高熵碳化物陶瓷相比,在相同的有效吸收带宽(2.3 GHz)下,涂层厚度减少了13.3%(1.5 mm降低到1.3 mm),其介电损耗主要来源于极化损耗和导电损耗。本工作制备的高熵碳化物陶瓷可以为研究制备新型环境适应、耐高温、抗冲击的高性能单相吸波材料提供新途径。

关键词：高熵碳化物陶瓷吸波材料吸波性能介电损耗熔盐法

基于转录组测序探究C-MET表达在非小细胞肺癌中的免疫调控机制

在线全文

学校读者我要写书评

暂无评论

实用医学杂志 2024年第1期40卷 7-12页

作者：徐越张言斌苏珊清远市人民医院广东清远511518 广州市红十字会医院广州510240 广州市胸科医院广州510095

目的通过转录组测序技术分析C-MET表达在非小细胞肺癌中的免疫调控机制。方法使用siRNA分子干扰技术将C-MET高表达肺腺癌细胞株(H1993)、肺鳞癌细胞株(EBC-1)的C-MET表达沉默,利用转录组测序技术检测C-MET沉默前后细胞差异表达的基因(DE... 详细信息

目的通过转录组测序技术分析C-MET表达在非小细胞肺癌中的免疫调控机制。方法使用siRNA分子干扰技术将C-MET高表达肺腺癌细胞株(H1993)、肺鳞癌细胞株(EBC-1)的C-MET表达沉默,利用转录组测序技术检测C-MET沉默前后细胞差异表达的基因(DEGs),通过生物信息学分析挖掘出C-MET可能参与调控的免疫微环境信号通路及相关基因。最后使用人免疫细胞与H1993、EBC-1共培养技术验证C-MET对免疫因子(INF-γ、INF-β、CXCL-10)的影响。结果通过转录组测序技术共检测到505个DEGs,其中H1993的C-MET调控前后表达差异组的表达差异基因共有38个,上调的差异表达基因有24个,下调的差异表达基因有14个。EBC-1的C-MET调控前后表达差异组的表达差异基因共有467个,上调的差异表达基因有347个,下调的差异表达基因121个。差异基因的KEGG分析表明,C-MET表达可能通过白细胞介素(IL-17)信号通路、白细胞分化、细胞因子受体活性、细胞周期、细胞因子-细胞因子受体相互作用参与免疫细胞调节因子的调控。使用肺癌细胞与人免疫细胞共同培养技术验证C-MET对免疫因子分泌的影响,Rt-qPCR检测结果提示:与C-MET高表达组共培养的PBMC中干扰素(INF-γ)的m RNA转录水平是低表达组的77倍、CXCL-10的mRNA转录水平是低表达组的1.6倍,INF-β的mRNA转录水平是低表达组的2倍。结论C-MET表达可能通过IL-17信号通路、白细胞分化、细胞因子受体活性通路参与肿瘤周围免疫微环境调控。

关键词：非小细胞肺癌 C-MET 免疫微环境表达谱测序

在线全文

学校读者我要写书评

暂无评论

浅议如何做好教育系统后勤服务管理工作

市场周刊 2024年第18期37卷 73-76页

作者：张雁宾西山区教育体育局基建设备科云南昆明650000

文章探讨了教育系统购买后勤服务管理工作的现存问题,并提出了一些改进和解决方案,包括完善供应商选择评价标准、细化合同内容、参考国家后勤服务指导定价以及加强内部采购规范,旨在提高教育系统后勤服务管理的透明度和效率,减少资金浪... 详细信息

文章探讨了教育系统购买后勤服务管理工作的现存问题,并提出了一些改进和解决方案,包括完善供应商选择评价标准、细化合同内容、参考国家后勤服务指导定价以及加强内部采购规范,旨在提高教育系统后勤服务管理的透明度和效率,减少资金浪费,促进教育系统可持续发展。

关键词：教育系统购买后勤服务管理

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

大陆下地壳

地学前缘 2024年第1期31卷 28-45页

作者：张艳斌翟明国周艳艳周李岗中国科学院地质与地球物理研究所岩石圈演化国家重点实验室北京100029 中国科学院大学行星与地球学院北京100049

大陆下地壳是连接岩石圈地幔和上地壳的“纽带”,是地壳与地幔交换最活跃的部位。上地幔与下地壳的部分熔融及下地壳一些岩石的拆沉还可直接导致壳-幔物质的交换、循环与重组。换言之,下地壳是壳-幔作用的一个极其重要的场所,底垫、拆... 详细信息

大陆下地壳是连接岩石圈地幔和上地壳的“纽带”,是地壳与地幔交换最活跃的部位。上地幔与下地壳的部分熔融及下地壳一些岩石的拆沉还可直接导致壳-幔物质的交换、循环与重组。换言之,下地壳是壳-幔作用的一个极其重要的场所,底垫、拆沉、深熔、高级变质和其他作用都在下地壳中发生和实现。然而,下地壳是以往研究地球深部和浅部关系时被“跳”过去的部位,没有得到足够的重视。克拉通化定义为大陆原来混沌的原地壳分异并形成稳定的上地壳和下地壳,并由此构建了稳定的壳-幔结构,这种空前的稳定关系从形成起一直维持到现在,是大陆演化、洋-陆与壳-幔相互作用的基础。在板块边界的造山过程中,如洋-陆的俯冲碰撞特别是陆-陆碰撞,可以形成不同大陆地块的陆壳叠置、加厚、垮塌、拆沉、底垫和重新稳定,在造山带根部形成新的下地壳,即造山带型下地壳。本文重点讨论了克拉通型下地壳演化过程,强调了其动力学意义及其在大陆动力学研究中的重要地位,建议在深地研究和学科布局中给与充分重视。

关键词：大陆下地壳地质过程壳幔作用克拉通造山带地球动力学

在线全文

学校读者我要写书评

暂无评论

刘开基与沁源围困战

长治学院学报 2024年第3期41卷 9-17页

作者：张艳斌新疆大学马克思主义学院新疆乌鲁木齐830000

沁源围困战被誉为敌后抗战中模范战例。沁源军民团结一心,英勇斗争,最终赢得胜利。刘开基时任沁源县委书记、围困指挥部政委,他领导沁源军民开展地雷战、在二沁大道伏击日伪军运输队、破坏日伪军维持计划等。这场围困战凸显出他以群众... 详细信息

沁源围困战被誉为敌后抗战中模范战例。沁源军民团结一心,英勇斗争,最终赢得胜利。刘开基时任沁源县委书记、围困指挥部政委,他领导沁源军民开展地雷战、在二沁大道伏击日伪军运输队、破坏日伪军维持计划等。这场围困战凸显出他以群众为本、对党忠诚、以毛泽东思想为指导原则的优秀品质。刘开基的战斗经历、个人品质以及他对沁源围困战的贡献对新时代弘扬伟大抗战精神具有重要意义。

关键词：沁源围困战刘开基战斗经历优秀品质

在线全文

学校读者我要写书评

暂无评论

基于UWB技术的矿山人员定位系统

能源与节能 2024年第6期 195-198页

作者：张彦斌晋能控股煤业集团轩岗煤电有限责任公司山西原平034100

在煤矿开采过程中,通过应用井下人员定位系统,可以有效提高矿井的安全性。基于此,首先阐述了超宽带UWB技术(无载波通信技术)及人员定位的基本原理,然后对定位系统框架进行了分析,该系统主要由井下、地面两部分构成,前者负责采集人员标... 详细信息

在煤矿开采过程中,通过应用井下人员定位系统,可以有效提高矿井的安全性。基于此,首先阐述了超宽带UWB技术(无载波通信技术)及人员定位的基本原理,然后对定位系统框架进行了分析,该系统主要由井下、地面两部分构成,前者负责采集人员标签信息,后者借助内置算法对标签坐标进行计算;其次,对人员标签和定位基站的硬件结构及设置进行了研究,两者硬件结构接近,主控芯片与无线信号收发芯片分别为STM 32、DW 1000;最后,对该系统的运行效果进行了试验,结果显示人员的定位误差小于1 m,有利于提高井下人员作业的安全性。

关键词：煤矿开采人员定位超宽带UWB技术