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An improved algorithm for McDowell’s analytical model of residual stress

null

《机械工程前沿（英文）》 2014年第9卷第2期页码 150-155 doi: 10.1007/s11465-014-0295-9

摘要：

The analytical model for two-dimensional elastoplastic rolling/sliding contact proposed by McDowell is an important tool for predicting residual stress in rolling/sliding processes. In application of the model, a problem of low predicting precision near the surface layer of the component is found. According to the volume-constancy of plastic deformation, an improved algorithm for McDowell’s model is proposed in order to improve its predicting accuracy of the surface residual stress. In the algorithm, a relationship between three normal stresses perpendicular to each other at any point within the component is derived, and the relationship is applied to McDowell’s model. Meanwhile, an unnecessary hypothesis proposed by McDowell can be eliminated to make the model more reasonable. The simulation results show that the surface residual stress predicted by modified method is much closer to the FEM results than the results predicted by McDowell’s model under the same simulation conditions.

关键词： residual stress McDowell’s model volume-constancy of plastic deformation FEM elastoplastic rolling/sliding contact

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超越巴斯德象限的基础研究动态演化模型及其实践内涵

张慧琴,王鑫,王旭,孙昌璞

《中国工程科学》 2021年第23卷第4期页码 145-152 doi: 10.15302/J-SSCAE-2021.04.017

摘要：

国家需求牵引的基础研究关系着我国源头创新能力和国际科技竞争力的提升，是颠覆性科技产生的重要驱动力，对我国创新型国家建设的重要性十分突出。为此，需要深入理解其内涵及基本发展规律，以更好引导基础研究的发展。本文回顾了布什科学研究线性模型的内涵、应用及其如何推广至巴斯德象限模型，在此基础上，考虑时间维度，引入基础度和应用度概念，提出由3个维度刻画的基础研究动态演化模型。为展示基础研究动态演化模型的适用性和优越性，以激光和强激光的发展为案例进行说明，阐述了国家需求牵引下基础研究、应用研究和技术开发之间的相互促进、螺旋上升的互动关系。基于本文模型描述的基础研究发展规律，针对需求牵引的基础研究，今后应更加强调学术诚信及可证伪性；要发挥基础研究对关键技术发展的方向性判定作用，并避免需求牵引引起的主观性诱导和误导。

关键词：基础研究，需求牵引，布什科学研究线性模型，巴斯德象限模型，基础研究动态演化模型，可证伪性

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Shear-flexural strength mechanical model for the design and assessment of reinforced concrete beams subjected

Antonio MARÍ,Antoni CLADERA,Jesús BAIRÁN,Eva OLLER,Carlos RIBAS

《结构与土木工程前沿（英文）》 2014年第8卷第4期页码 337-353 doi: 10.1007/s11709-014-0081-0

摘要： A mechanical model recently developed for the shear strength of slender reinforced concrete beams with and without shear reinforcement is presented and extended to elements with uniformly distributed loads, specially focusing on practical design and assessment in this paper. The shear strength is considered to be the sum of the shear transferred by the concrete compression chord, along the crack, due to residual tensile and frictional stresses, by the stirrups and, if they exist, by the longitudinal reinforcement. Based on the principles of structural mechanics simple expressions have been derived separately for each shear transfer action and for their interaction at ultimate limit state. The predictions of the model have been compared to those obtained by using the EC2, MC2010 and ACI 318-08 provisions and they fit very well the available experimental results from the recently published ACI-DAfStb databases of shear tests on slender reinforced concrete beams with and without stirrups. Finally, a detailed application example has been presented, obtaining each contributing component to the shear strength and the assumed shape and position of the critical crack.

关键词： shear strength mechanical model reinforced concrete design assessment shear tests

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基于马尔可夫到达过程的两级可修备件（S-1，S）库存优化模型

陈童,黎放,狄鹏

《中国工程科学》 2015年第17卷第5期页码 113-119

摘要：，采用马尔可夫到达过程（MAP）描述备件需求规律，考虑有限维修设施的情况，假设故障件维修时间、备件运输时间以及采购时间均服从phase-type（PH）分布，建立了一种描述能力更强、解析计算性更好的（S-1，S）库存优化模型，并推导出系统缺货量分布函数；然后通过算例演示了模型的优化效果，验证了模型的正确性和适用性。

关键词：（S-1，S）库存策略；两级库存；可修备件；马尔可夫到达过程

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Toward energy finance market transition: Does China’s oil futures shake up global spots market?

《工程管理前沿（英文）》页码 409-424 doi: 10.1007/s42524-022-0207-3

摘要： China is breaking through the petrodollar system, establishing RMB-dominating crude oil futures market. The country is achieving a milestone in its transition to energy finance market internationalization. This study explores the price leadership of China’s crude oil futures and identifies its price co-movement to uncover whether it truly shakes up the global oil spots market. First, we find that for oil spots under different gravities, China’s oil futures is only a net price information receiver from light-, medium-, and heavy-gravity oil spots, but it has a relatively stronger price co-movement with these three spots. Second, for oil spots under different sulfur contents, China’s oil futures still has weak price leadership in sweet, neutral, and sour oil spots, but it has strong co-movement with them. Third, for oil spots under different geographical origins, China’s oil futures shows price leadership in East Asian and Australian oil spots at the medium- and long-run time scales and strong price co-movement with East Asian, Middle Eastern, Latin American and Australian oil spots. China’s oil futures may not have good price leadership in global spots market, but it features favorable price co-movement.

关键词： China’s oil futures price information spillover price co-movement BK spillover index BDECO model

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Multi-objective dynamic optimization model for China’s road transport energy technology switching

Dan GAO , Zheng LI , Feng FU , Linwei MA

《能源前沿（英文）》 2009年第3卷第3期页码 247-253 doi: 10.1007/s11708-009-0048-3

摘要： Deducting the future switching of the road transport energy technology is one of the key preconditions for relative technology development planning. However, one of the difficulties is to address the issue of multi-objective and conflicting constrains, e.g., minimizing the climate mitigation or minimizing economic cost. In this paper, a dynamic optimization model was established, which can be used to analyze the road transport energy technology switching under multi-objective constrains. Through one case study, a series of solutions could be derived to provide decision-makers with the flexibility to choose the appropriate solution with respect to the given situation.

关键词： technology switching transport energy system multi-objective CO₂ mitigation

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高分辨率地球重力场模型DQM99

石磐,夏哲仁,孙中苗,李迎春

《中国工程科学》 1999年第1卷第3期页码 51-55

摘要：

地球扰动位的球谐展开式表示是地球重力场模型应用最广泛的一种表示方法。目前通用的位系数模型的分辨率是0.5°，最高完全阶次为360。由于全球重力数据覆盖的密度和数据精度差别较大，所以已知的重力场模型的实际分辨率及其精度也因地区而异，故重力场模型的精化是一个漫长的过程，局部积分谱权综合法是改善已知重力场模型的有效而简便的方法。基于重力场模型OSU91A及EGM96，利用我国15′×15′及5′×5′重力异常，我们解算了更高阶次的地球重力场模型DQM99A、B、C、D四个模型，给出了精度比较分析结果。

关键词：地球重力场模型DQM99 地球形状地球位系数模型

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Temperature control of transfer roller’s bearing based on finite element analysis

Peng ZHANG, Yourong LI, Han XIAO

《机械工程前沿（英文）》 2009年第4卷第2期页码 215-218 doi: 10.1007/s11465-009-0026-9

摘要： After a heat preservation cover is installed on the main rolling line, the heat dissipation environment of the transfer roller working on the heat preservation cover is changed. To ensure the normal production, a reasonable working jet capacity of the roller neck is derived. First, a globe model of the transfer roller is built for finite element analysis. Second, the sub-model of the fixed end bearing is built and the boundary condition of the sub-model is supplied by the results of the globe model. The analysis result of the sub-model shows that the temperature of the transfer roller bearing exceeds 85°C a rolling periodicity later. With finite element analysis, the heat flux is obtained and the minimum working jet capacity is derived.

关键词： transfer roller bearing finite element analysis sub-model temperature control

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Preparation of manganese (III) acetylacetonate nanoparticles via an environmentally benign route

S. Shalaby, H. Abdallah

《化学科学与工程前沿（英文）》 2013年第7卷第3期页码 329-337 doi: 10.1007/s11705-013-1339-0

摘要： With the hope of overcoming the generation of hazardous materials to human health and environment, serious and great endeavor have been made in catalyst fabrication using green chemistry technology. In this paper, the manganese (III) acetylacetonate nanoparticles with diameters of about 146 nm were prepared by a simple and environmentally benign route based on hydrolysis of KMnO followed by reaction with acetylacetone in rapid stirring rate or ultrasonication. The as-prepared samples were characterized by X-ray diffraction, energy dispersive X-ray fluorescence (EDIX), Fourier transfer infrared spectroscopy and scanning electron microscope. Various parameters were investigated, and the pure and stable crystals of manganese (III) acetylacetonate could be obtained in 98% conversion at a molar ratio 7∶1 of acetylacetone to KMnO and 75°C after 60 min. We further proposed a mathematical model, and the predicted results from model were in good agreement with experimental results.

关键词： green chemistry manganese (III) acetylacetonate reaction conversion Mathematical model

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HVAC系统的模糊预测函数控制器设计

吕红丽,贾磊,王雷,高瑞

《中国工程科学》 2006年第8卷第9期页码 65-68

摘要：

针对暖通空调HVAC系统中由于存在高度非线性、时变特征以及扰动和不确定性等因素而难以控制的特点，提出基于Takagi-Sugeno(T-S)模糊模型的预测函数控制器设计方法。该方法通过最小二乘辨识算法建立系统的模糊T-S模型，然后基于模糊全局线性化预测模型，采用预测函数控制算法设计系统控制律。仿真实验结果表明该算法是一种跟踪性能好、鲁棒性强的有效控制方法。

关键词： T-S模糊模型预测函数控制最小二乘算法 HVAC系统

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Soil health: model programs in the USA

Wayne HONEYCUTT, Cristine L.S.

《农业科学与工程前沿（英文）》 2020年第7卷第3期页码 356-361 doi: 10.15302/J-FASE-2020340

摘要：

Population growth, increasing drought, and natural resources degradation are significant global issues. Fortunately, management practices to improve soil health can address many of these issues in ways that are both good for the farmer and the environment. In 2012, the United States Department of Agriculture (USDA) Natural Resources Conservation Service initiated its “Unlock the Secrets in the Soil” campaign to assist farmers and ranchers with adopting soil health systems. Other notable efforts at the federal level include research and education projects by USDA Agricultural Research Service, National Institute of Food and Agriculture, and Sustainable Agriculture Research and Education program. The importance of improving soil health is also recognized far beyond federal government programs. The Soil Health Institute, a nonprofit charity, was established to safeguard and enhance the vitality and productivity of soil through scientific research and adoption. Crop commodity organizations are promoting soil health, such as the Soil Health Partnership. The Nature Conservancy is helping companies and private landowners incorporate soil health into their sustainability efforts. Such efforts are supported by the Foundation for Food and Agriculture Research, as well as by some of the leading global food companies such as General Mills. These are just a few of the many efforts to improve soil health in the USA. The significance of the expanding global population, natural resource challenges, and responsibilities to current and future generations truly make enhancing soil health a global imperative.

关键词： carbon sequestration climate change environmental quality farmer programs water quality

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虚拟企业CRM系统的原型分析和设计

邓峰,刘现民,杨肖鸳

《中国工程科学》 2004年第6卷第10期页码 83-85

摘要：

描述了虚拟企业CRM（客户关系管理）系统的特点，分析了虚拟企业CRM的信息流，在此基础上给出了一个分布式的虚拟企业CRM运作系统，其必须由虚拟企业CRM的协调企业统一管理和协调，并构造了虚拟企业CRM系统中的协调企业的功能模块参考结构，提出了实现虚拟企业CRM的技术体系参考模型。

关键词：虚拟企业的CRM 信息流功能模块技术体系

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A comprehensive analysis of a 3-P (Pa) S spatial parallel manipulator

Yuzhe LIU,Liping WANG,Jun WU,Jinsong WANG

《机械工程前沿（英文）》 2015年第10卷第1期页码 7-19 doi: 10.1007/s11465-015-0324-3

摘要：

In this paper, a novel 3-degree of freedom (3-DOF) spatial parallel kinematic machine (PKM) is analyzed. The manipulator owns three main motions (two rotations and one translation) and three concomitant motions (one rotation and two translations). At first, the structure of this spatial PKM is simplified according to the characteristic of each limb. Secondly, the kinematics model of this spatial PKM is set up. In addition, the relationship between the main motions and concomitant motions is studied. The workspaces respectively based on the outputs and inputs are derived and analyzed. Furthermore, the velocity model is put forward. Two indexes based on the velocity model are employed to investigate the performance of this spatial PKM. At last, the output error model can be obtained and simulated. The comprehensive kinematics analysis in this paper is greatly useful for the future applications of this spatial PKM.

关键词： parallel mechanism concomitant motions kinematics workspaces error model

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R158Q and G212S, novel pathogenic compound heterozygous variants in of Gitelman syndrome

《医学前沿（英文）》 2022年第16卷第6期页码 932-945 doi: 10.1007/s11684-022-0963-9

摘要： The dysfunction of Na⁺-Cl⁻ cotransporter (NCC) caused by mutations in solute carrier family12, member 3 gene (SLC12A3) primarily causes Gitelman syndrome (GS). In identifying the pathogenicity of R158Q and G212S variants of SLC12A3, we evaluated the pathogenicity by bioinformatic, expression, and localization analysis of two variants from a patient in our cohort. The prediction of mutant protein showed that p.R158Q and p.G212S could alter protein’s three-dimensional structure. Western blot showed a decrease of mutant Ncc. Immunofluorescence of the two mutations revealed a diffuse positive staining below the plasma membrane. Meanwhile, we conducted a compound heterozygous model—Ncc R156Q/G210S mice corresponding to human NCC R158Q/G212S. Ncc^R156Q/G210S mice clearly exhibited typical GS features, including hypokalemia, hypomagnesemia, and increased fractional excretion of K⁺ and Mg²⁺ with a normal blood pressure level, which made Ncc^R156Q/G210S mice an optimal mouse model for further study of GS. A dramatic decrease and abnormal localization of the mutant Ncc in distal convoluted tubules contributed to the phenotype. The hydrochlorothiazide test showed a loss of function of mutant Ncc in Ncc^R156Q/G210S mice. These findings indicated that R158Q and G212S variants of SLC12A3 were pathogenic variants of GS.

关键词： Gitelman syndrome mouse model compound heterozygous hypokalemia Slc12a3

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Correlations for estimating solar radiation using sunshine hours and temperature measurement in Osogbo, Osun State, Nigeria

S. OHUNAKIN, M. S. ADARAMOLA, O. M. OYEWOLA, R. O. FAGBENLE

《能源前沿（英文）》 2013年第7卷第2期页码 214-222 doi: 10.1007/s11708-013-0241-2

摘要： In this study, the global solar radiation on horizontal surface in Osogbo, Osun state, Nigeria was analyzed using 11-year data (1997–2007). Correlations using linear and quadratic expressions were developed to relate the global solar radiation on horizontal surface based on relative sunshine hours and temperature measurements for evaluating the monthly average daily global solar radiation. The calculated monthly clearness index values indicate that the prevailing weather condition in Osogbo is heavily overcast. All the developed quadratic correlations gave better correlation coefficients (0.834, 0.872 and 0.823 respectively) than the linear models. However, the Hargreaves and Samani related based quadratic model gave the best among the three developed quadratic expressions and is therefore suggested for estimating the monthly global radiation in this site and its surroundings.

关键词： global solar radiation Hargreaves model sunshine hour ambient temperatures Osogbo