检索结果-南通市图书馆

More on Fatigue Verification of Class 1 Nuclear Power Piping According to ASME BPV Code

在线全文

学校读者我要写书评

暂无评论

Journal of Energy and Power Engineering 2014年第6期8卷 1112-1123页

作者： Lingfu Zeng Lennart G. Jansson section for Nuclear Technology AF-Industry AB G6teborg 401 51 Sweden section for Technical Analysis AF-Industry AB Goteborg 401 51 Sweden

Fatigue verification of Class 1 nuclear power piping according to ASME Boiler and Pressure Vessel Code, section III, NB-3600, which is often discussed in connection to power uprate and life-extension of aging reactors in recent years, is dealt with. Key parameters involved in the fatigue verification, e.g., the alternating stress intensity Salt, the penalty factor Ke and the cumulative damage factor U, and relevant computational procedures applicable for the assessment of low-cycle fatigue failure using strain-controlled data, are particularly addressed. A so-called simplified elastic-plastic discontinuity analysis for alternative verification when fatigue requirements found unsatisfactory, and the procedures provided in NB-3600 for evaluating the alternating stress intensity S,j,, are reviewed in detail. An in-depth discussion is given to alternative procedures suggested earlier by the authors using nonlinear finite element analyses, which uses a nonlinear finite element analysis for directly determining the alternating stress, thus eliminating uncertainties resulted from the use of the penalty factor Ke. Using this alternative, unavoidable plastic strains can be correctly taken into account in a computationally affordable way, and the reliability of the verification will not be affected by uncertainties introduced in the simplified elastic-plastic analysis.

关键词： Piping fatigue ASME BPV code finite element cyclic plasticity.

Separation and Enrichment of Rare Earth Elements in Phosphorite in Xinhua,Zhijin,Guizhou

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2006年第z2期24卷 413-414页

作者：张杰孙传敏杨国峰谢飞 Mineral industry College Guizhou University Geoscience College Chengdu University

The phosphorite ores-deposits rich in rare earth elements(REE) in Zhijin, Xinhua, Guizhuo occurs in the early Cambrian Meishucun and at the bottom part of Qiongzhusi stage (the upper layer of phosphorites), belonging to Yangzi stratum section. The living creature scraps was proved existent in dolomitic-phosphorites by experiments, The REE could be extracted to provide the worthy data for the further using. Adopting the HNO3 to extract REE, through the ion exchange method, the REE recovery rate could be reached 85.44% , having certain reference value.

关键词： rare earth elements phosphorites separation and enrichment

在线全文

学校读者我要写书评

暂无评论

人工智能技术和环境保护

世界环境 1989年第1期 9-12页

作者： Tadago Shi Yamanaka 张玺 Deputy chief Middle EastAfrica SectionTrade Policy BureauMinistry of Trade and Industry

1.前言人工智能(AI:artificial intelligence)是将人类的认识机能储存到电子计算机系统中,使其具有认识功能的技术。这项研究工作始于1960年左右。通过二十多年来的基础研究和近年来电子计算机的发展,AI这项超先进技术也得到飞速的发展... 详细信息

1.前言人工智能(AI:artificial intelligence)是将人类的认识机能储存到电子计算机系统中,使其具有认识功能的技术。这项研究工作始于1960年左右。通过二十多年来的基础研究和近年来电子计算机的发展,AI这项超先进技术也得到飞速的发展。各企业界,为了提高产品质量、降低成本、提高工作效率,也都对AI技术寄予热切希望。在这种急需的情况下,呈现了一派AI技术开发应用的新局面。今后AI技术在环境保护、防治公害、废物处理等方面也将起到重要作用,目前这方面的工作已经展开并取得进展。根据上述情况,本文拟对何谓AI技术、其现状、应用及其发展前景作一简要介绍。

关键词：人工智能技术认识功能 intelligence 计算机系统基础研究产品质量发展前景降低成本废塑料工作效率

Joint method for reconstructing three-dimensional temperature of flame using Lucy-Richardson and nearest neighbor filtering using light-field imaging

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2019年第7期62卷 1232-1243页

作者： LI TianJiao YUAN Yuan SHUAI Yong TAN HePing Key Laboratory of Aerospace Thermophysics Ministry of Industry and Information Technology Harbin Institute of Technology

The real-time measurement and reconstruction of three-dimensional temperature are essential when studying the combustion process inside a flame. In the proposed sectioned flame light field imaging model, flame sections are reconstructed based on the characteristics identified using the Lucy-Richardson or nearest neighbor filtering methods, or a joint method involving a combination of both, to improve on the accuracy of two-dimensional temperature reconstruction. Compared to the results of a previous work, the proposed method increases the resolution in the depth of field direction and the extraction of the flame temperature of all sections from the same height ensures the accuracy of the reconstructed temperature distribution across the cross-section of the flame. The relative error when compared to the actual flame is less than 10%. Thus, this approach allows the accurate estimation of the three-dimensional temperature distribution inside a flame, and enables the rapid and effective reconstruction of the three-dimensional temperature field.

关键词： radiative transfer flame light field imaging temperature estimation

MECHANICAL PROPERTIES AND SIZE EFFECTS OF SINGLE CRYSTAL SILICON

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2006年第2期19卷 290-293页

作者： HAN Guangping　 LIU Kai WANG Xiuhong School of Mechanical and Instrumental Engineering Xi＇ an University of TechnologyXi＇ an 710048 China Department of industry Engineering Zhengzhou Institute of Aeronautical Industry ManagementZhengzhou 450015 China

Six kinds of micro bridge-beam specimens with different sizes are fabricated using photolithography technology for bending test. Beam specimens with trapezoidal section could be representatives of those with rectangle and square section, which are usually applied in MEMS. Nano indentation method used in bending test can be applied to both elastic and plastic materials. Also, some mechanical properties parameters such as the modulus of elasticity, hardness and the bending strength are obtained. The average modulus of elasticity of SCS is 170.295 0±2.485 0 GPa, showing no size effects, but the bending strength ranges from 3.24 GPa to 10.15 GPa, displaying strong size effects, and the average hardness is 9.496 7±1.753 3 GPa,in which no obvious size effects are observed.

关键词： Mechanical properties Modulus of elasticity Size effect Nano indentation Bending test

Physical and Mechanical Properties of Catalpa bungei Clones and Estimation of the Properties by Near-Infrared Spectroscopy

在线全文

学校读者我要写书评

暂无评论

Journal of Renewable Materials 2022年第12期10卷 3285-3302页

作者： Rui Wang Lanlan Shi Yurong Wang Research Institute of Wood industry Chinese Academy of ForestryBeijing100091China

Air-dry density,modulus of rupture(MOR),modulus of elasticity(MOE),compressive strength parallel to grain,and hardness of Catalpa bungei clones were investigated in this study with feasibility of predicting these properties by near infrared(NIR)*** best candidate Luoqiu 3'has been selected from three clones based on wood physical and mechanical property *** values of wood physical and mechanical properties have been found in the corewood compared to the *** were significant positive correlations between the air-dry density and mechanical *** from Cross section for air dry density,compressive strength parallel to grain,and hardness yielded prediction models with better effects,along with the best MOR and MOE modeling effects resulted from average sections'spectra *** scatter correction(MSC)+Savitzky-Golay(S-G)smoothing method has been proved to be the most applicable *** addition,the predictions from five point sampling method were slightly better than three point ***,results suggest NIR spectroscopy was viable to predict the physical and mechanical properties of C bungei dones with methods developed in this study proved effective in preliminary screening.

关键词： C.bungei wood density mechanical properties near-infrared spectroscopy

Key Technologies and Applications of the Design and Manufacturing of Non-Circular TBMs

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Engineering 2017年第6期3卷 905-914页

作者： Jianbin Li China Railway Hi-Tech industry Corporation Limited Beijing 100070 China

With the rapid development of the exploitation of underground space, more and more large- or super- large-diameter tunnel-boring machines （TBMs） are being employed to construct underground space projects. At present, because conventional circular TBMs cannot completely meet the requirements of underground space exploitation regarding the cross-section and space-utilization ratio, non-circular TBMs. which are the tunneling equipment for an ideal cross-section, have become the new market growth point. This paper first presents the technical features and development status of non-circular TBMs. Next, in reference to typical projects and technological innovation, this paper investigates key techniques including shield design optimization, multi-cutterhead excavation, special-shaped segment erection, and soil conditioning in loess strata for a rectangular pipe-jacking machine and a horseshoe-shaped TBM, in order to provide a set of feasible solutions for the design, manufacture, and construction of non-circular TBMs. Relevant engineering practice shows that non-circular TBMs with customized design and manufacture have great advantages in terms of construction schedule, settlement control, and space utilization.

关键词： Non-circular TBMs Rectangular pipe-jacking machine Horseshoe-shaped TBM Underground space exploitation

Advancing sandstone reservoir compressibility prediction:A correlation-driven methodology

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Research 2024年第2期9卷 273-279页

作者： Tarek Ganat Meftah Hrairi Amr Badawy Vahid Khosravi Mohammed Abdalla Department of Petroleum Chemical Engineering Sultan Qaboos UniversityP.O.Box 50Al-Khod123MuscatOman Department of Mechanical and Aerospace Engineering International Islamic University MalaysiaP.O.Box 1050728Kuala LumpurMalaysia Reservoir Engineering section Petronas Carigali SDN BHDP.O.Box 10500088Kuala LumpurMalaysia Department of Chemical and Petroleum Engineering Faculty of EngineeringTechnologyand Built EnvironmentUCSI University56000Kuala LumpurMalaysia Chemical&Petroleum Engineering United Arab Emirates UniversityP.O.Box No.15551Al AinUAE

This study presents a correlation-based approach for predicting the compressibility of sandstone reservoir *** study proposes a matrix of new empirical equations that significantly improve the precision of measuring the pore volume compressibility,with the most optimal fit of results based on a cubic polynomial *** accuracy of the calculations was validated through comparison with actual data using root mean square method,and the suggested correlations significantly enhance the precise prediction of rock compressibility in sandstone *** this study,the source of data collection is consolidated and unconsolidated sandstone from East Asia offshore ***,variations in compressibility with net overburden pressure over the course of the field's lifespan have been *** results demonstrate the application of regression analysis in establishing a network of linkages between independent and dependent *** proposed correlations for consolidated and unconsolidated sandstones offer a remarkable improvement in the accurate calculation of rock compressibility compared to traditional laboratory procedures,with an average error of 2.5%compared to 5-10%for laboratory *** approach of this study offers a cost-effective and time-efficient alternative to remarkedly enhance the overall performance of sandstone reservoirs in the oil and gas industry.

关键词： Compressibility Consolidated and unconsolidated sandstone Rock properties Rock mechanics

Today’s protected areas:supporting a more sustainable future for humanity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Integrative Zoology 2020年第6期15卷 603-616页

作者： Jeffrey A.MCNEELY Society for Conservation Biology Asia section Cha-AmPetchburiThailand

Nature provides significant benefits to people,especially those living in and around protected *** services from protected areas include producing wild food,supporting biodiversity and water cycles,regulating climate,and providing cultural services like better health,tourism,and legacy for future *** economic terms,the flows of ecosystem services provided by protected areas are worth hundreds of billions of dollars each year,well justifying the costs of managing these sites,but protected areas are suffering from environmental problems such as impacts from human population growth,rural poverty,growing demands for natural resources,land use change that degrades ecosystem productivity,invasive non-native species that harm natural ecosystems,and climate change that is affecting all *** these linked challenges will require mobilizing all parts of the economy,including the protected area *** example,protected areas can take a leadership role in rural development,expand the conservation estate to half of the planet through connectivity and improved management of more of the non-agricultural land,enhance the prominent role of protected areas in contributing to climate change mitigation and adaptation,encourage productive research on applying modern technology to protected areas management,seek broader private sector participation in conserving biodiversity and ecosystem services,and include protected areas as relevant parties in relevant trade and other international *** protected area managers embrace this broader role,they will find enthusiastic public support for this contribution to a sustainable human society.

关键词： aichi target climate change economic benefit ecosystem service landscape conservation protected area