书讯

正《阀门手册——选型》——本书由化学工业出版社于2013年1月出版发行,张清双、尹玉杰、明赐东主编。全书针对阀门用户的实际需求,在介绍了各种阀门选型基本知识的基础上,重点介绍了各种阀门的结构、技术特点、应用场合及选用原则等内容,阀门种类包括闸阀、球阀、蝶阀、截止阀、止回阀、旋塞阀、柱塞阀、隔膜阀、电磁阀、节流阀、蒸汽疏水阀、减压阀、安全阀、调节阀、放料阀、塑料阀门、陶瓷阀门以及供水管网、水     

润华集团ERP系统的澎湃力

润华集团股份有限公司是一家跨地区、跨行业的综合性大型股份制企业集团,山东省政府确定的全省首批51家现代企业制度试点单位之一.经营领域涉及汽车销售、汽车修理、配件供应、旧机动车交易、客运出租、汽车租赁、机动车拍卖、房地产开发、制药、进出口贸易、物业管理、广告企划等众多行业,并参股金融业,基本确立了以汽车服务业、药业、房地产业为支柱产业,投资、贸易、实业协调并进的发展格局.     

《现代科学仪器》征稿启事

《现代科学仪器》是在国家有关领导人和著名科学家的指导和大力支持下诞生的。它是中国科技核心期刊,是国内最重要的以介绍和评论国内外仪器为主的综合性科技期刊。读者对象为各行各业实验室、试验室、研究室应用与维护仪器的科技人员及购置与管理仪器设备的人员;从事高技术及其产品研制生产的科技人员;各级有关管理决策人员;大专院校师生等。涉及物理、化学、生物、医疗卫生、制药、农业、地矿、机械、电子、石油、化工、冶金、能源、交通、环保、建筑、轻工、商检、     

2007年中国机床工具行业十大新闻

1.中央和地方省市主要领导频繁视察机床行业企业,国家为数控机床产业发展创造了空前良好的发展环境 胡锦涛、吴邦国、温家宝、贾庆林、李长春等党和国家领导人以及辽宁、黑龙江、山东、江苏、云南、湖北、广东、陕西、浙江、天津、重庆等省市主要领导相继视察了机床工具厂和数控系统厂.各级领导频繁视察,为数控机床产业的发展创造了空前良好的发展环境.     

TNG系列多功能提取浓缩回收机组

成都永泰制药化工机械厂是专业生产制药机械、化工机械、食品机械成套设备的厂家。其生产的TNG系列多功能提取浓缩回收机组适用于中药、生化、食品等行业的常压、水煎、温浸、强循环渗漉、芳香油提取和有机溶媒回收及提取液、中药、植物、动物、食品、化工液料的浓缩。     

“全国第一届近红外光谱学术会议”在北京成功召开

由中国分析测试协会和中国石油学会石油炼制分会共同主办的全国第一届近红外光谱学术会议于2006年10月28日至30日在北京西郊宾馆的会议中心举行。来自清华大学、浙江大学、天津大学、南开大学、吉林大学、上海交通大学、西安交通大学、哈尔滨工业大学、中国农业大学、中南大学、第二军医大学、后勤工程学院、第二炮兵工程学院、海军航空工程学院、暨南大学、广西大学、首都师范大学、山东轻工业学院、中国计量学院、中科院光机所、中科院上海技术物理研究所、     

陈光祖 超制造业正在兴起

正当前,世界汽车产业正步入经济危机的复苏年代,汽车产业正酝酿着,以信息化为标志的高新产业群广泛和深入的应用,不断渗透到传统汽车产业诸要素中,促进汽车产业结构的转型升级,形成新兴的生产力,诸如新能源、云计算、大数据、3D打印技术、超级计算机、量子计算技术、微电子技术、纳米、光电、超导、激光、化合生物、复合材料、高铁技术、4G、先进军工技术和智能技术等等,都正在不断融入汽车产业中,这已成为世界汽车产业共同遵循的,科学的规律,中国     

《现代科学仪器》征稿启事

《现代科学仪器》是在国家有关领导人和著名科学家的指导和大力支持下诞生的。它是中国科技核心期刊,是国内最重要的以介绍和评论国内外仪器为主的综合性科技期刊。读者对象为各行各业实验室、试验室、研究室应用与维护仪器的科技人员及购置与管理仪器设备的人员;从事高技术及其产品研制生产的科技人员;各级有关管理决策人员;大专院校师生等。涉及物理、化学、生物、医疗卫生、制药、农业、地矿、机械、电子、石油、化工、冶金、能源、交通、环保、建筑、轻工、商检、技术监督等各项科技领域。     

两只狼的交战

一位年迈的北美切罗基人教导孙子们人生真谛。他说：“在我内心深处,一直在进行着一场鏖战。交战是在两只狼中间展开的。一只狼是恶的——它代表恐惧、生气、悲伤、悔恨、贪婪、傲慢、自怜、怨恨、自卑、谎言、妄自尊大、高傲、自私和不忠;另外一只狼是善的——它代表喜悦、和平、爱、希望、承担责任、宁静、谦逊、仁慈、宽容、友谊、同情、慷慨、真理和忠贞。     

电子万能材料试验机

电子万能材料试验机主要适合于橡胶、轮胎、胶管、胶带、鞋底、塑料、薄膜、压克力、FRP、ABS、EVA、PU、铝塑管、复合材料、防水材料、纤维、纺织、电线电缆、纸张、金属箔、带、丝线、弹簧、木材、医药包装材料、胶带等进行拉伸、压缩、撕裂、剥离等力学性能的测试、分析。     

叶切面最大厚度的数值计算方法

叶切面最大厚度计算是螺旋曲面加工准备过程中必要的环节.探讨适合于叶切面最大厚度的数值计算方法.详细介绍叶切面厚度数值计算所包括的叶切面最大厚度区域搜索、叶切面最大厚度精确计算过程.     

机械基础虚拟实验室的开发及应用

简要介绍了虚拟实验室在国内外的研究现状,分析了机械基础虚拟实验室的基本要求,探讨了利用仿真技术对机械基础虚拟实验室的开发过程,以组合机构为例介绍了机械基础虚拟实验室的应用。     

Natural frequencies of vibration of a class of solids composed of layers of isotropic materials

In a recent paper, the Ritz method with simple algebraic polynomials as trial functions was used to obtain an eigenvalue equation for the free vibration of a class of homogeneous solids with cavities. The method presented is here extended to the study of a class of non-homogeneous solids, in which each solid is composed of a number of isotropic layers with different material properties. The Cartesian coordinate system is used to describe the geometry of the solid which is modelled by means of a segment bounded by the yz, zx and xy orthogonal coordinate planes and by two curved surfaces which are defined by fairly general polynomial expressions in the coordinates x, y and z. The surface representing the interface between two material layers in the solid is also described by a polynomial expression in the coordinates x, y and z. In order to demonstrate the accuracy of the approach, natural frequencies are given for both a two- and three-layered spherical shell and for a homogeneous hollow cylinder, as computed using the present approach, and are compared with those obtained using an exact solution. Results are then given for a number of two- and three-layered cylinders and, to demonstrate the versatility of the approach, natural frequencies are given for a five-layered cantilevered beam with a central circular hole as well as for a number of composite solids of more general shape.     

电涡流传感器互换性的研究

本文介绍了电涡流传感器互换性的概念及提高互换性的思路和方法,强调了工艺这一关键因素。这些对其它类型的传感器同样有着一定的指导意义。     

面向绿色制造的产品模块化设计研究综述

阐述了绿色产品生命周期的涵义,分析了绿色产品生命周期各阶段的特性及关联关系,对目前存在的绿色模块化设计技术和方法进行了分类总结。根据绿色产品生命周期各阶段研究侧重点不同,将目前绿色制造模块化设计归纳为面向产品生命周期模块化设计、绿色设计模块化设计、环境意识模块化设计、再制造模块化设计、可拆卸模块化设计、维修模块化设计、回收模块化设计、重用模块化设计及其他模块化设计,并对其相应的模块化设计方法进行了综述分析。最后展望了今后的研究趋势。     

在线修正大型起重机剩余寿命的研究

基于修正Miner疲劳损伤累积理论,采用在线修正的名义应力估算疲劳寿命的方法,设计了一套大型起重机在线寿命预测系统。通过数据的实时测量对剩余寿命进行修正,更好地结合实际,提供了一种准确、实用的预测起重机安全剩余寿命的新手段。     

Application of Monte Carlo simulation for estimation of uncertainty of four-point roundness measurements of rolls

Large-scale rotors in the paper and steel industry are called rolls. Rolls are reground at regular intervals and roundness measurements are made throughout the machining process. Measurement systems for roundness and diameter variation of large rolls (diameter <2000 mm) are available on the market, and generally use two to four sensors and a roundness measurement algorithm. These methods are intended to separate roundness of the rotor from its movement. The hybrid four-point method has improved accuracy, even for harmonic component amplitudes. For reliable measurement results, every measurement should be traceable with an estimation of measurement uncertainty. In this paper, the Monte-Carlo method is used for uncertainty evaluation of the harmonic components of the measured roundness profile under typical industrial conditions. According to the evaluation, the standard uncertainties for the harmonic amplitudes with the hybrid method are below 0.5 μm for the even harmonics and from 1.5 μm to 2.5 μm for the odd harmonics, when the standard uncertainty for the four probes is 0.3 μm each. The standard uncertainty for roundness deviation is 3.3 μm.     

膨胀套导向机构的设计

通过分析膨胀套在实际使用产生滑移受阻现象、卡死现象原因的实质,并在分析产生问题原因的基础上提出了改进措施即：增加导向机构。     

Out of plane stability of circular arches

An elastic buckling theory is developed for thin-walled arches. Using the principle of minimum total potential energy derives the governing differential equations. An explicit and clear approximation of the curvature effect is made in the derivation process. Closed form solutions are obtained for arches subjected to equal and opposite end moments (uniform bending) and to uniformly distributed radial loads (uniform compression). Also, closed form solutions for the torsional buckling moment of braced arches in uniform bending and for the torsional buckling load of braced arches in uniform compression are obtained. The solutions are compared with previous theoretical results.     

A new approach for determination of the coefficient of thermal expansion of asphalt concrete

A new approach for determining the coefficient of thermal expansion (CTE) of asphalt concrete (AC), based on thermoelasticity and using a distributed thermocouple and strain gauge apparatus, is proposed. The thermoelastic model for an instrumented hollow cylindrical AC specimen was established. Experiments were conducted with six scenarios of thermal flux for simulating different levels of heating on AC pavement. Three approaches for interpreting the CTE according to the readings of the thermocouple and strain gauge are provided, with different CTE measurements expected and observed. Terms associated with strain measuring accuracy derived from thermoelasticity are defined. The thermal calibration of instrument readings was shown to be necessary for obtaining accurate CTE readings for AC specimens. The CTE readings obtained in this study showed strong agreement with values reported in the literature. The proposed measuring approach is shown to be simple to install and theoretically founded.