检索结果-南通市图书馆

Microstructure and Mechanical Properties of Martensitic Stainless Steel 6Cr15MoV

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第3期19卷 56-61页

作者： MA dang-shen1, chi Hong-xiao1,2, ZHOU Jian1, YONG Qi-long1,2 (1. Institute for Structural Materials, Central Iron and Steel Research Institute, Beijing 100081, china 2. Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan, china) Institute for Structural Materials Central Iron and Steel Research Institute Beijing China Faculty of Materials Science and Engineering Kunming University of Science and Technology Kunming Yunnan China

Martensitic stainless steel containing Cr of 12% to 18%（mass percent） are common utilized in quenching and tempering processes for knife and cutlery steel. The properties obtained in these materials are significantly influ- enced by matrix composition after heat treatment, especially as Cr and C content. Comprehensive considered the hardness and corrosion resistance, a new type martensitic stainless steel 6Crl5MoV has been developed. The effect of heat treatment processes on microstructure and mechanical properties of 6Crl5MoV martensitic stainless steel is emphatically researched. Thermo-Calc software has been carried out to thermodynamic calculation; OM, SEM and TEM have been carried out to microstructure observation; hardness and impact toughness test have been carried out to evaluate the mechanical properties. Results show that the equilibrium carbide in 6Cr15MoV steel is M23 C6 car- bide, and the M23 C6 carbides finely distributed in annealed microstructure. 6Crl5MoV martensitic stainless steel has a wider quenching temperature range, the hardness value of steel 6Cr15MoV can reach to HRC 60.8 to HRC 61.6 when quenched at 1 060 to 1 100 ℃. Finely distributed carbides will exist in quenched microstructure, and effectively inhabit the growth of austenite grain. With the increasing of quenching temperature, the volume fraction of undis- solved carbides will decrease. The excellent comprehensive mechanical properties can be obtained by quenched at 1 060 to 1 100℃ with tempered at 100 to 150 ℃, and it is mainly due to the high carbon martensite and fine grain size. At these temperature ranges, the hardness will retain about HRC 59.2 to HRC 61.6 and the Charpy U-notch impact toughness will retain about 17.3 to 20 J. A lot of M23C6 carbides precipitated from martensite matrix, at the same time along the boundaries of martensite lathes which leading to the decrease of impact toughness when tempered at 500 to 540 ℃. The MaC precipitants also existed in the martensite mat

关键词： martensitic stainless steel microstructure mechanical property

Tai chi:A Much-Loved Symbol of china

在线全文

学校读者我要写书评

暂无评论

china Today 2018年第7期67卷 66-67页

作者： dang XIAOFEI

TAI chi is a unique chinese cultural symbol,often portrayed on-screen as a supreme form of *** real life,however,it is a traditional form of physical exercise,which is becoming increasingly popular,and practiced by pe... 详细信息

关键词：中国文化傣族 chi 生活

Taijiquan: Heritage for Humanity

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

china Today 2021年第3期70卷 64-66页

作者： dang XIAOFEI 不详

ON December 17,2020,Taijiquan(also known as tai chi)was inscribed on the UNESCO’s Representative List of the Intangible Cultural Heritage of *** traditional physical practice,which originated in china,is“characterized by relaxed,circular movements that work in concert with breath regulation,and the cultivation of a righteous and neutral mind”according to a description from the UNESCO *** is an expression of china’s unique traditional culture and not only improves physical fitness,but also cultivates the mind.

关键词： UNESCO originated relaxed

The Belt and Road Initiative Boosts Green Development

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

china Today 2018年第10期67卷 50-52页

作者： dang XIAOFEI

AS people become more consciously aware of the world around them, environmental protection is high up on the list of priorities from both public and private sectors across the globe. In the process, the contradiction between development and environmental protection is always a subject of much heated debate. Being acutely aware of this, china highlights the concept of ecological progress in the Belt and Road Initiative,

关键词：开发道路格林环境保护优先级

Calibration of a neutron dose rate meter in various neutron standard fields

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

Nuclear Science and Techniques 2020年第6期31卷 75-82页

作者： Tuan Khai Nguyen Hoai-Nam Tran Quynh Ngoc Nguyen Thi My Linh dang Van Loat Bui Thiansin Liamsuwan Ngoc-Thiem Le Vietnam Agency for Radiation and Nuclear Safety 113 Tran Duy HungHanoi 100000Vietnam Institute of Fundamental and Applied Sciences Duy Tan UniversityHo Chi Minh 700000Vietnam Faculty of Natural Sciences Duy Tan University3 Quang TrungDa Nang 550000Vietnam Institute for Nuclear Science and Technology VINATOM179 Hoang Quoc VietHanoi 100000Vietnam Faculty of Physics VNU University of Science334 Nguyen TraiHanoi 100000Vietnam Nuclear Research and Development Division Thailand Institute of Nuclear TechnologyOngkharakNakorn NayokThailand 7 Faculty of Medicine and Public HealthHRH Princess Chulabhorn College of Medical ScienceChulabhorn Royal AcademyBangkokThailand

This paper presents the calibration of a neutron dose rate meter and the evaluation of its calibration factors(CFs)in several neutron standard fields(i.e.,two standard fields with bare sources of252Cf and241Am-Be,and five simulated workplace fields with241Am-Be moderated sources).The calibration in standard fields with bare sources was conducted by following the recommendations of the ISO 8529 *** measured total neutron ambient dose equivalent rates,denoted as H*(10)tot,were analyzed to obtain direct components,denoted as H*(10)dir,using a reduced fitting *** CF was then calculated as the ratio between the conventional true value of the neutron ambient dose equivalent rate in a free field,denoted as H*(10)FF,and the value of H*(10)*** contrast,in the simulated workplace neutron fields,the calibration of the neutron dose rate meter was conducted by following the ISO 12789 *** CF was calculated as the ratio between the values of H*(10)totmeasured by a standard instrument(i.e.,Bonner sphere spectrometer)and the neutron dose rate *** CF values were obtained in the range of 0.88–*** standard uncertainties(k=1)of the CFs were determined to be in the range of approximately 6.6–13.1%.

关键词： Neutron standard fields Neutron dose rate meter Calibration factor 252Cf source 241AmBe source

在线全文

学校读者我要写书评

暂无评论

超声波辅助提取青稞β-葡聚糖工艺优化

食品科技 2014年第12期39卷 217-221页

作者：徐菲党斌迟德钊青海大学农林科学院西宁810016 青海省农林科学院西宁810016 青海省青藏高原农产品加工重点实验室西宁810016

采用超声波辅助方法从青稞麸皮中提取β-葡聚糖。研究了水料比、pH、超声波功率、提取时间和提取温度对其得率的影响,通过正交试验优化了提取工艺。结果表明,超声波辅助提取青稞β-葡聚糖的最优工艺为:水料比1:18,提取温度45℃,超声波功... 详细信息

采用超声波辅助方法从青稞麸皮中提取β-葡聚糖。研究了水料比、pH、超声波功率、提取时间和提取温度对其得率的影响,通过正交试验优化了提取工艺。结果表明,超声波辅助提取青稞β-葡聚糖的最优工艺为:水料比1:18,提取温度45℃,超声波功率500 W,p H9,提取时间25 min,此条件下β-葡聚糖得率可达2.36%。各因素对β-葡聚糖得率的影响大小依次为:水料比>提取温度>超声波功率>pH>提取时间。比较了TCA法、Sevage法、木瓜蛋白酶法的除蛋白效果,木瓜蛋白酶法最佳,蛋白质去除率可达87.84%,β-葡聚糖保留率可达90.58%。

关键词：超声波青稞麸皮 β-葡聚糖提取

在线全文

学校读者我要写书评

暂无评论

植物结构铝基复合材料的制备及热学性能

南京理工大学学报 2009年第6期33卷 809-813页

作者：王天驰范同祥张荻熊党生南京理工大学材料科学与工程系江苏南京210094 上海交通大学金属基复合材料国家重点实验室上海200030

为研制新型复合材料,将植物结构引入到金属基复合材料的制备中。该文以柳桉木材为模板,先将其转变为多孔碳,再通过铝合金和硅树脂的浸渍,制备了具有木材结构的Al/C、Al/(SiC+C)两种铝基复合材料,并通过扫面电镜、热膨胀仪和导热仪对复... 详细信息

为研制新型复合材料,将植物结构引入到金属基复合材料的制备中。该文以柳桉木材为模板,先将其转变为多孔碳,再通过铝合金和硅树脂的浸渍,制备了具有木材结构的Al/C、Al/(SiC+C)两种铝基复合材料,并通过扫面电镜、热膨胀仪和导热仪对复合材料的微观结构、热膨胀性能及导热性能进行了研究,建立了导热模型。结果发现该复合材料的结构由所选模板的结构决定,这与以往结构完全由人为控制的金属基复合材料不同;并且其热膨胀系数明显低于铝合金,导热系数(98.2和95.4 W.m-1.K-1)远高于由木材转化的多孔碳(2.22 W.m-1.K-1)。

关键词：木材金属基复合材料微观结构导热系数热膨胀导热模型

基于GM-ES-GASVR组合模型的丽江国内旅游需求预测

在线全文

学校读者我要写书评

暂无评论

数学的实践与认识 2017年第8期47卷 279-287页

作者：党婷彭乃驰云南大学旅游文化学院信息科学与技术系云南丽江674199

构建适合于预测丽江国内旅游需求的预测模型,对推动丽江旅游业的发展具有重要意义.研究发现灰色GM(1,1)模型、三次指数平滑模型与GA-SVR模型都适用于预测丽江国内旅游需求,且GA-SVR模型为这三个单项模型中的最优模型.在此基础上,利用变... 详细信息

构建适合于预测丽江国内旅游需求的预测模型,对推动丽江旅游业的发展具有重要意义.研究发现灰色GM(1,1)模型、三次指数平滑模型与GA-SVR模型都适用于预测丽江国内旅游需求,且GA-SVR模型为这三个单项模型中的最优模型.在此基础上,利用变权方法建立GM-ES-GASVR组合预测模型.通过对拟合与测试结果的对比分析,表明GM-ES-GASVR变权组合预测模型比单一模型的拟合与测试效果都有较大改善.

关键词：变权组合预测灰色GM(1,1) 三次指数平滑 GA-SVR 丽江国内旅游

电渣重熔连续定向凝固M2高速钢铸态组织的研究

在线全文

学校读者我要写书评

暂无评论

材料工程 2013年第7期41卷 29-34页

作者：占礼春迟宏宵马党参付锐蒋业华昆明理工大学材料科学与工程学院昆明650093 钢铁研究总院特殊钢研究所北京100081 钢铁研究总院高温材料研究所北京100081

研究了传统电渣重熔工艺(ESR)和电渣重熔连续定向凝固技术(ESR-CDS)所得到的M2高速钢铸态显微组织。结果表明:采用ESR工艺得到铸态组织边部为树枝晶且部分出现了三次枝晶,心部为粗大的等轴晶,晶粒之间有网状碳化物,铸锭的偏析较为严重,... 详细信息

研究了传统电渣重熔工艺(ESR)和电渣重熔连续定向凝固技术(ESR-CDS)所得到的M2高速钢铸态显微组织。结果表明:采用ESR工艺得到铸态组织边部为树枝晶且部分出现了三次枝晶,心部为粗大的等轴晶,晶粒之间有网状碳化物,铸锭的偏析较为严重,经深腐蚀凝固组织基体与碳化物过渡区较为疏松、粗糙,部分基体内部出现了细小的裂纹。而采用ESR-CDS工艺得到铸态组织边部和心部都以较为细小的树枝晶为主,组织中存在比较多的"不连续的复合规则型"的碳化物,组织较为均匀,经深腐蚀,碳化物与基体过渡区圆滑。

关键词：电渣重熔连续定向凝固 M2高速钢铸态组织