国外对汽车用镁前景的看法

1镁对汽车制造厂家的吸引力在汽车制造业中,经济学继续促进推行汽车车身减重计划。但是,作财务决策没有成本计算用的方程式那样简单。生产的汽车要达到几个功能性目标。如果生产出来的汽车达到了它的重量目标,或者是超过了它的平均燃油经济指标的预期值,汽车生产厂家在可能获得低成本零部件的情况下,他们实际上会增加汽车车身的重量。虽然,从改善汽车性能的观点看,这样做是违反常规的。但是,汽车生产厂家用高密度材料作汽车构件,可以提高汽车的利润。在过度竞争的汽车市场上求生存,这样做是必然的。另一方面,如果生产出来的汽车没有达到必须…     

铝合金汽车车身板应用现状及需求前景

本文从汽车节能减排对汽车轻量化的要求、以及使用铝合金汽车车身板对汽车轻量化的重要意义出发,介绍了铝合金汽车车身板在汽车上的典型应用以及减重效果,通过相关机构调查数据并结合一些典型案例,分析了目前欧盟、北美及日本等国家和地区铝合金汽车车身板在汽车覆盖件上的应用现状、生产现状以及发展趋势,同时对国内铝合金汽车车身板的应用现状、生产现状进行阐述,并对铝合金汽车车身板的需求前景、世界主要汽车生产国家和地区的需求量以及与超轻型高强度钢板在汽车领域的竞争进行了分析和预测。文章最后针对铝合金汽车车身板发展的制约因素,从成立汽车铝材联合开发机构、开发新合金新工艺、完善生产线、提高性价比等几方面对我国铝合金汽车车身板的发展提出建议。     

高校汽车文化教育的必要性与教学研究

汽车文化教育是汽车专业人才培养的重要一环,也是全面提高大学生综合素质的重要途径.阐述了汽车文化的内涵,论述了汽车文化教育对培养汽车专业人才的必要性,对汽车文化教育的基本内容和教学方法进行了探讨.     

汽车钢制车轮等产品质量认证有新规

为促进汽车生产企业确保汽车产品质量,最近,中国汽车产品认证委员会决定对汽车钢制车轮、汽车交流发电机、汽车分电器、汽车信号闪光器、汽车电喇叭、汽车气弹簧、汽车机械式转向器总成、真空助力器     

汽车用镁 美加在行动

汽车用镁,是世界汽车生产大国共同关注的话题。本文介绍了镁工业现状,评述了汽车轻量化的必要性,并指出镁是汽车轻量化的理想材料。另外,对美国、加拿大等汽车生产大国所进行的汽车用镁活动给予介绍。     

汽车轻量化及铝合金的应用

汽车轻量化的重大意义Major signif icance of popularization of light-weighted cars汽车轻量化是汽车工业健康发展的需要随着汽车工业的发展,汽车产量和保有量逐年增加,汽车在给人们出行带来方便的同时,也带来了油耗、安全和环保这三大问题。2005年,中国汽车产量已超过550万辆,汽车保有量已超过3000万辆,全球汽车保有量已超过2.5亿辆,汽车工业不仅是发达国家的支柱产业,而且一个城市的机动化更是城市发展的标志。汽车行驶要耗油,同时也会排出有害气体、污染环境、对人的身体和生命造成危害。为保证汽车工业的健康发展,各国针对汽车工业…     

未来汽车理念

加入WTO给中国汽车敲响警钟，同时也带来无限的机遇，国家以及汽车公司必须加大对汽车设计的研究与投入，确立一种积极正确的汽车设计的理念，广泛开展概念汽车的设计。高科技的普及和应用使得汽车产品更新换代的步伐越来越快，也使得中国汽车工业的自主研发水平和技术水平与国际上的差距越来越大，在概念汽车的开发方面则更是相差的极为悬殊。     

汽车服务工程专业汽车商务课程群框架构建

论述了汽车服务工程专业汽车商务课程群建设的必要性,对汽车商务课程进行划分并构建课程群,提出了汽车服务工程专业汽车商务课程群建设的研究思路。     

轻量化与轻金属材料应用

在当今发动机技术提升难度日益加大、新能源汽车还无法大规模产业化的背景下,不论对传统燃油汽车,还是新能源汽车,汽车轻量化技术都是一项共性的基础技术。大力发展并推进汽车轻量化技术成为节能、环保的主要手段之一。出于节能减排、低碳环保的要求,汽车轻量化将是未来汽车工业的发展方向。     

浅析汽车板的开发与应用

针对汽车结构对于汽车板的要求和挑战进行分析,对汽车板的需求和相关特点进行总结,对汽车板的开发和应用进行研究,并结合实际案例指出了汽车板的未来发展方向。     

2004年铁合金市场回顾与2005年展望

2004年国际和国内铁合金价格波动较大，全年价格总体水平较往年有较大增长。2004年我国铁合金行业产销两旺，全年产量和出口量均创历史新高，市场价格较往年也有明显改善。但是，铁合金行业发展过热已引起国家有关部门和业界的高度重视，并相继出台了一系列相关的产业政策和调控、指导性措施，对整个铁合金行业的发展产生了深远影响。文章从生产、消费及进出口等方面对2004年中国铁合金市场进行了分析并对2005年市场前景进行了预测。     

Integrated Two-Dimensional Surface and Three-Dimensional Subsurface Contaminant Transport Model Considering Soil Erosion and Sorption

To investigate the complex hydrological, morphodynamic, and environmental processes in watersheds, a physically-based integrated two-dimensional (2D) surface and three-dimensional (3D) subsurface model for flow, soil erosion and transport, and contaminant transport in the surface-subsurface system is presented in this paper. The model simulates the rainfall-induced surface flow by solving the depth-averaged 2D diffusion wave equation and the variably-saturated subsurface flow by solving the 3D mixed-form Richards equation. The surface and subsurface flow equations are coupled using the continuity conditions of pressure and exchange flux at the ground surface. The model uses the concept of nonequilibrium in the depth-averaged 2D simulation of nonuniform total-load sediment transport in upland fields, considering detachments by rainsplash and hydraulic erosion driven by surface flow. The integrated 2D surface and 3D subsurface contaminant transport model takes into account the contaminant changes due to sediment sorption and desorption, as well as exchanges between surface and subsurface domains due to infiltration, diffusion, and bed change. The model applies the same set of surface equations of flow, sediment, and contaminant transport for describing both upland areas and streams, so that no special treatments are required at their interface. The established model has been evaluated by comparisons with published experimental, numerical, and analytical data and then applied in an agricultural watershed. The model is suitable for wetland areas and agricultural watersheds in which streams are not very narrow and deep, and meanwhile a relatively fine mesh that can distinguish the streams is preferred.     

Evaporation Research: Review and Interpretation

Literature regarding evaporation from soil, wet plant surfaces, and sprinkler droplets was examined, normalized, and interpreted. Much of the evaporation literature is difficult to compare and interpret; this paper offers comparisons and discussions of various findings by others as well as by the writers. Techniques of measuring and estimating evaporation from irrigation and rainfall are discussed. The partitioning between increased evaporation and decreased transpiration from a variety of research is quantified. Factors that impact the various forms of evaporation are listed and quantified. This review and summary will provide practitioners and researchers with theoretical and practical guidance on measurement techniques and estimates of evaporation under a wide range of conditions.     

Dynamic Modeling of Hydraulic Shovel Excavators for Geomaterials

The hydraulic shovel excavator has found significant applications in surface mining, construction, and geotechnical operations due to its flexibility and mobility. The key to high availability and utilization of this shovel is adequate understanding of machine dynamics and machine-formation interactions among other technical, operating, safety, and economic factors. These shovels are capital intensive, complex in design and operation within severely constrained environments. Detailed dynamic modeling and analysis are required to understand their effective utilization for achieving efficient operating performance and economic useful lives. Previous attempts at solving these problems are limited because they do not provide knowledge on the resistive forces and moments for efficient excavation. In this paper, the Newton-Euler techniques are used to develop hydraulic shovel dynamic models with numerical examples. Detailed analysis of the results shows that: (1) the kinematics of the stick-bucket joint (joint 3) is the most critical and effective control of this joint and is important input into efficient excavation design and execution; and (2) the highest resistive moments occur between the duration of 1.5 and 2.0?s after the start of formation excavation and the highest magnitudes are 1,500?Nm (for stick), 900?Nm (for bucket), and 600?Nm (for boom). Based on these results, the path trajectories, dynamic velocity and acceleration profiles, and dimensioned parameters for optimum feed force, torques, and momentum of shovel boom-bucket assembly can be modeled and used for efficient excavation. The optimum digging forces and resistances for the hydraulic shovel excavator can also be modeled and used to predict optimum excavation performance.     

Probabilistic Capacity Models for Corroding Posttensioning Strands Calibrated Using Laboratory Results

The presence of air voids, moisture, and chlorides inside tendons or ducts was cited as a reason for the early age strand corrosion and failure in the Mid-bay, Sunshine Skyway, and Niles Channel posttensioned (PT) bridges in Florida, United States. Although rare, these incidents call for frequent inspection and structural reliability assessment of PT bridges exposed to moisture and chlorides. This paper develops and presents probabilistic strand capacity models that are needed to assess the structural reliability of such PT bridges and recommends a time frequency of inspection. A total of 384 strand test specimens were exposed to various void, moisture, and chloride concentration conditions for 12 and 21 months; the remaining tension capacities were then determined. Using this experimental data and a Bayesian approach, six probabilistic capacity models were developed based on the void type. The mean absolute percentage errors of these models are less than 4%, indicating that reasonably accurate prediction of the strand capacity is possible, when void, aggressive moisture, and chloride conditions are present.     

天铁科技成果管理工作实践

论述了科技成果管理的内容和意义,结合企业实际介绍了天铁科技管理的制度、体系及实施效果。通过科技创新体系和成果管理制度建设,“十一五”期间促进了科技成果的开发和转化,有多个项目分别列人天津市技术创新重点为项目、天津市二十项重点项目,推动了企业持续快速发展。     

天铁物料结算系统的开发设计

天铁为了解决物料结算由于手工操作出现的差错率高、控制成本困难等问题,开发设计了计算机物料结算系统。从系统的安全性、网络和硬件的实现等方面,介绍了该系统的主要功能和特点及运行情况。系统运行情况证明,该系统的开发实现了数据共享和集中存储,完善了采购和销售的各环节,程序运行稳定,提高了工作效率。     

钛渣酸解过程中物相变化特征探讨

明确物相变化是剖析钛渣酸解机理和改进酸解工艺的关键点之一.综合应用化学分析、X射线衍射(XRD)分析、矿物解离分析以及扫描电镜形貌分析对某74钛渣酸解过程中主要物相的含量、形貌变化以及Ti、Si两种元素的含量及赋存变化进行了研究.结果表明:钛渣主要由黑钛石和辉石组成,酸解过程中黑钛石含量逐渐减小,辉石含量逐渐增加;反应...     

Behind closed doors: In-home workers' experience of sexual harassment and workplace violence.

The authors developed and tested a structural model predicting personal and organizational consequences of workplace violence and sexual harassment for health care professionals who work inside their client's home. The model suggests that workplace violence and sexual harassment predict fear of their recurrence in the workplace, which in turn predicts negative mood (anxiety and anger) and perceptions of injustice. In turn, fear, negative mood, and perceived injustice predict lower affective commitment and enhanced withdrawal intentions, poor interpersonal job performance, greater neglect, and cognitive difficulties. The results supported the model and showed that the associations of workplace violence and sexual harassment with organizational and personal outcomes are indirect, mediated by fear and negative mood. Conceptual implications for understanding sexual harassment and workplace violence, and future research directions, are suggested. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design Error Classification, Causation, and Prevention in Construction Engineering

Construction and engineering practitioners have found it increasingly difficult to learn from their mistakes, particularly with regard to the prevention, identification and/or containment of design errors. Yet, design errors have been the root cause of numerous catastrophic accidents that have resulted in the death and injury of workers and members of the public. This paper examines and classifies the nature of error and design error causation in construction and engineering projects. A review of the normative literature revealed that design errors are caused by an array of factors that can work interdependently. A generic framework is developed that classifies design error according to people, the organization, and project is presented. The paper suggests that people, over and above organizational and project management strategies, have the greatest propensity to reduce errors through the process of situated learning and knowing. This is because the working environment provided by an organization and the processes used to deliver construction and engineering projects influence the nature and ability of people to undertake tasks. Consequently, there is no single but rather a multitude of strategies that need to be adopted in congruence to reduce design errors so that safety and project performance are ameliorated.