第二讲 对磨料磨具的再认识(二)

四、粒度粒度是指磨料的颗粒尺寸,粒度对磨削生产效率和工件表面粗糙度影响比较大。新标准规定磨粒粒度按颗粒尺寸大小分为41个号,即:4~#、5~#、6~#、7~#、 8~#、 10~#、 12~#、 14~#、 15~#、20~#、22~#、24~#、 30~#、 36~#、 40~#、46~#、54~#、60~#、 70~#、 80~#、 90~#、 100~#、(?) 150~#、180~#、220~#、240~#、W63、W50、W10、W28、W20、W14、W10、(?) W5、W 3.5、W2.5、W1.5、W1.0、W0.5、     

企业名录

主要经营品种及范围:泵、减速机、风机、压缩机、输送设备、起重设备、建筑机械、机床、电动机、发动机、锅炉、电焊机、等离子切割机及以上机械设备配、附件。传动带、传动链、皮带轮、链轮、齿轮、蜗轮、蜗杆,联轴器、轴承、轴承座、轴瓦。紧定衬套、锁紧螺母、锁紧垫圈等。制动器,管、阀门、法兰、水表、管接,机械密封、橡胶密封、羊毛毡密封、石棉密封、油墨、铅粉等。润滑用具及装置、润滑油,化工反应釜,紧固件,有色金属,板、棒、保湿材料、     

书讯

代码专辑名称专辑光盘学科范围M－A理工辑A（数理科学）半年刊数学、力学、物理、生物、天文、地理、测绘、资源、气象、水文、海洋、地质、地球物理学M－B理工辑B（化学化工能源与材料）半年刊化学、化工、矿冶、石油、天然气、金属及金属工艺、煤炭、轻工、劳动保护、环境、材料M－C理工辑C（工业技术）半年刊工业通用技术及设备、机械、仪表、航空、航天、交通运输、水利工程、农业工程、建筑、动力、原子能技术、电工技术M－D农业辑半年刊农业基础科学、农艺学、植保、农作物、园艺、林业、畜牧、动物医学、狩猎、蚕蜂、水产、渔业…     

优泰动态信号分析系统

数据采集分析与系统分析：超大容量连续数据采集、功率谱、功率谱密度、能量谱密度、线性谱、倒频谱、三维谱阵、相位谱、相位差谱、1／3倍频程、相干频谱、共振解调谱、波形包络、地毯谱、阶次谱、阶次谱阵、时域光标带最大熵谱、传递函数分析、相关分析、概率分析、李萨如图、声学分析、应变花计算、播放器、高精度阻尼计算、转速测量、文件转换。     

CCMT2018刀具量具量仪展前综述

正本届CCMT有来自境内外的230多家企业将展出工量具产品,主要境内展商包括株洲钻石、成都工具所、上海工具、哈量、成量、厦门金鹭、郑州钻石、恒锋工具、苏州阿诺、上海山田、大连远东、森泰英格、株洲华锐、苏州锑玛、无锡方寸、欧科亿、成都成林、澳克泰、广陆、青量、桂量、上量、深圳中图等;境外展商包括伊斯卡、瓦尔特、三菱综合材料、欧士机、玛帕、埃莫克法兰肯、泰珂洛、多马工具、雄克、翰默、申克、卡尔蔡司、京瓷、柯尔柏     

会展信息

一、机电零件 1、铸件、锻件、冲压件、粉末冶金件,标准件、紧固件、弹簧、链、链轮、齿轮、轴、曲轴、连杆、轴套、轴承、轴瓦、传动带,气动元件、液压件、密封件、电动工具零配件 2、各类电子元器件、接插件、电路板、集成块、线圈、电感、各类传感器、继电器     

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。     

四百种常见重要工程(五)

54.chemical engineering化学工程 涉及食品、发酵剂、油脂、洗剂、化妆品、橡胶、塑料、色材、接着剂、纤维、纸,木材、摄影器材、皮革、杂货、燃料、药品、影片、录音带与录像带等无机化学品与有机化学品生产的流程、机     

第十七届中国制冷展即将拉开帷幕

由中国国际贸易促进委员会北京市分会、中国制冷学会、中国制冷空调工业协会、上海市制冷学会、上海冷冻空调行业协会共同主办的第十七届“国际制冷、空调、供暖、通风及食品冷冻加工展览会(”中国制冷展)将于2006年4月11—13日在上海新国际博览中心举办。参加本届展会的将有来自德国、印度、韩国、泰国、美国、澳大利亚、比利时、巴西、加拿大、丹麦、埃及、芬兰、法国、印度尼西亚、意大利、日本、马来西亚、挪威、波兰、葡萄牙、瑞典、瑞士、新加坡、西班牙、土耳其、阿联酋、英国以及中国(包括港台地区)等全球30个国家和地区的891家厂商…     

投稿须知

<正>一、投稿内容涉及现代仪器仪表新技术、新工艺、新产品、系统开发、检测测量及在线分析方面的研究成果、实践经验、评论与建议;工业自动化仪表与控制系统在机械电子、石油化工、冶金、电力、通信、环保、航空航天、市政建设、农业、食品加工、纺织、轻工、交通、建筑、军工、计算机等行业的解决方案;科学仪器与装     

高效液相色谱法同时测定鱼肉中十三种磺胺类药物残留

建立高效液相色谱法测定鱼肉中磺胺嘧啶、磺胺噻唑、磺胺吡啶、磺胺甲基嘧啶、磺胺甲噻二唑、磺胺二甲嘧啶、磺胺氯哒嗪、磺胺甲恶唑、磺胺间甲氧嘧啶、磺胺二甲异恶唑、磺胺喹恶啉、磺胺间二甲氧嘧啶、磺胺甲氧哒嗪等13种磺胺类药物残留量的方法。用C_(18)柱,紫外检测器,流动相为甲醇-1%乙酸溶液,流速1.0mL/min,柱温40℃,于270nm波长处检测。     

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State-of-the-art on theories and applications of cable-driven parallel robots

Cable-driven parallel robot (CDPR) is a type of high-performance robot that integrates cable-driven kinematic chains and parallel mechanism theory. It inherits the high dynamics and heavy load capacities of the parallel mechanism and significantly improves the workspace, cost and energy efficiency simultaneously. As a result, CDPRs have had irreplaceable roles in industrial and technological fields, such as astronomy, aerospace, logistics, simulators, and rehabilitation. CDPRs follow the cutting-edge trend of rigid–flexible fusion, reflect advanced lightweight design concepts, and have become a frontier topic in robotics research. This paper summarizes the kernel theories and developments of CDPRs, covering configuration design, cable-force distribution, workspace and stiffness, performance evaluation, optimization, and motion control. Kinematic modeling, workspace analysis, and cable-force solution are illustrated. Stiffness and dynamic modeling methods are discussed. To further promote the development, researchers should strengthen the investigation in configuration innovation, rapid calculation of workspace, performance evaluation, stiffness control, and rigid–flexible coupling dynamics. In addition, engineering problems such as cable materials, reliability design, and a unified control framework require attention.     

Chemical Assessment of Bottled Drinking Waters by IC,GC, and ICP‐MS

Abstract

Bottled water brands, consisting of both local and imported types, collected from Doha city, Qatar, were evaluated for their suitability for human consumption. Water quality constituents that were analyzed include trihalomethanes (THM) by GC‐ECD, turbidity, TDS, total hardness, total alkalinity, pH, EC, major anions by IC, and major cations and trace metals by ICP‐MS. The data obtained were compared with the WHO and the USEPA drinking water standards. As, Se, Ba, and Cu were undetected in all water samples. The levels of potential toxic metals in the studied brands were generally low, except for three brands that had Cd and Pb which exceeded the WHO limits. Fluoride was generally present in all bottled water brands at levels less than the lower optimum level. The reported data for pH, turbidity, TDS, EC, alkalinity, hardness, major anions, and major cations were generally in compliance with the WHO and the USEPA standards, with exception of five brands, where the levels of TDS, EC, F, and NO₃ exceeded the WHO recommended limits. Also, it was found that the concentrations of NO₃ F, Fe, Cr, Zn, and Pb were higher in the local brands. The levels of Cd, Mn, Ca, Mg, EC, alkalinity, SO₄, TDS, THM, and hardness were higher in the domestic brands, when compared to the imported ones. The levels of Cl, pH, turbidity, and Na in the domestic brands were comparable to imported ones. Three THM were found in 29% of water samples with three brands having CHCl₂Br and CHCl₃ levels exceeding the WHO standards.

Comparison of the results of this study with the reported label values of both domestic and imported bottled water showed good agreement with pH and K values, but significant variation for Ca, Mg, F, NO₃, and SO₄ in the imported brands and relatively low variation in the domestic brands. The results of chemical analysis of SRM 1460, trace elements in water, were generally in good agreement with NIST certified values.     

Morphology and Distribution of Antennal Sensilla of the Bean Bug Riptortus pedestris (Hemiptera: Alydidae)

The bean bug, Riptortus pedestris is a major pest of bean pods and some tree fruits in north‐east Asian countries. Scanning electron microscopy was conducted to investigate the morphology and distribution of antennal sensilla of R. pedestris to help in understanding the sensory mechanisms of the bug. Average antennal lengths of male and female R. pedestris were 11.00 mm and 9.84 mm, respectively, consisting of four distinct segments, scape, pedicel, basiflagellum, and distiflagellum. Based on the gross appearance, the antennal sensilla were classified into four major types (trichodea, basiconica, chaetica, and coeloconica), which could be further classified into four trichoid, three basiconic, four chaotic, and two coeloconic subtypes, based on their size, tip shape, presence of socket, and surface structure. Among them, two subtypes of trichoid sensilla, all three subtypes of basiconic sensilla, four subtypes of chaetic sensilla and two subtypes of coeloconic sensilla had numerous pores along the surface, suggesting their olfactory function. Nine subtypes (2 trichoid, 1 basiconic, 4 chaetic, and 2 coeloconic subtypes) showed a distinct socket structure at the base. Among the four antennal segments, the distiflagellum possessed highest number of sensilla. Trichoid sensilla were most abundant, followed by basiconic, chaetic, and coeloconic sensilla. Each subtype of sensilla exhibited distinct distribution profile along the four antennal segments. Two subtypes of trichoid sensilla, one subtype of basiconic sensilla and one subtype of chaetica sensilla were distributed on scape, pedicel, and basiflagellum, whereas distribution of other subtypes of sensilla was confined to basiflagellum and distiflagellum. Microsc. Res. Tech. 79:501–511, 2016. © 2016 Wiley Periodicals, Inc.     

Localization of metals in cells of pterygote insects

Insects maintain the equilibrium of their internal milieu by diffusion mechanisms, but more frequently by a substantial storage of metals in the cells of numerous organs: digestive tract, Malpighian tubules, fat body, integument, and genital organs. This storage implies the precipitation, of numerous cations (Ca, Mg, K, Mn, Fe, Zn, Cu) in a structure called the spherocrystal, which originates from the endoplasmic reticulum-Golgi complex: elements precipitate on a glycosaminoglycan nucleus in thin peripheral strata. Some spherocrystals contain exclusively mineral compounds, frequently phosphates, whereas others may contain organic compounds such as urates. In some species mineralized lysosomes store Ca, Fe, Zn, and Cu. When fed additional metals found in the environment, insects such as cockroach and ant are able to stay alive and to trap the metals (Cd or Pb, for example) in the peripheral strata of spherocrystals; the cytoplasm is not altered. It seems that these insects are able to resist exposures to high levels of toxic metals. The lysosomes are able to retain toxic heavy metals (Cd or Hg, for example) within metallothionein-like proteins.     

Advantages of a combined method of decalcification compared to EDTA

Decalcification of mineralized tissues is an essential step during tissue processing in the routine histopathology. The time required for complete decalcification, and the effect of decalcifier on cellular and tissue morphology are important parameters which influence the selection of decalcifying agents. In this study, we compared a decalcifying solution (ETDA) composed of both acid and chelating agents to a classical and well‐known decalcifying agent (EDTA). To this purpose, the optic density of bone radiographs, residual calcium analysis, bone sample weight, and histological and immunohistochemical analysis were performed. Our data suggest that, similarly to EDTA, the ETDA solution completely removes the calcium ions from the samples enabling easy sectioning. However, unlike the EDTA, this agent takes much less time. Furthermore, both agents showed comparable decalcification efficacy, and similarly, they did not produce cellular, tissue or antigenicity impairments. Therefore, ETDA may be a suitable option when it is necessary an association between a rapid and complete removal of calcium minerals, and a suitable preservation of structure and antigenicity of tissues. Microsc. Res. Tech. 78:111–118, 2015. © 2014 Wiley Periodicals, Inc.     

Experimental Study of Leakage and Friction of Rectangular,Elastomeric Hydraulic Seals for Reciprocating Motion from −54 to +135°C and Pressures from 3.4 to 34.5 MPa

Hydraulic seals for reciprocating motion are used in mechanisms, machines, and devices most commonly in automotive, aerospace, marine, and general industrial sectors. Applications vary from those of a cheap medical injector and tire pump to mechanisms controlling ultra-expensive equipment in power stations, ships, and space vehicles. Unfortunately, elastomeric seals are flexible solids with nonlinear response to changes in their environment involving stress or strain, heat transfer, interaction with fluids, and aging. Unsurprisingly, research into their performance is ongoing for more than 80 years. The present experimental study is a step toward a better understanding of sealing performance in a broad range of temperatures and sealed pressures. Hundreds of experiments were conducted in conformance to international standards and in controlled conditions within tight tolerances of all parameters, including mechanical properties, solid dimensions, and operating conditions. Rectangular elastomeric seals for aerospace applications were studied under sealed pressures of 3.4 to 34.5 MPa (500 to 5,000 lb/in²) and in ambient temperatures of ?54 to +135°C. The combined range of pressures and temperatures exceeds what is available in the literature, particularly on the low temperature side. Other parameters varied in the experiments include the seal dimensions and radial interference, the surface roughness of the cooperating shafts, and the support of seals by one or two back-up rings. The results of the parametric study, summarized in eight tables and two figures, have been sorted for ascending leakage and friction force at each of the studied ambient temperatures for quick selection of optimal values.     

以ABS为代表的提高汽车制动性新技术

探讨了提高汽车制动性的新技术;重点介绍ABS（制动防抱死装置）的历史、原理、结构、分类、应用和发展趋势;筒略介绍了ASR、EBD、EHB、ESP、ESS、VDSC等技术。     

UPLC-LTQ-Orbitrap-MS法快速分析鬼箭羽中的化学成分

利用UPLC-LTQ-Orbitrap-MS技术结合文献报道的鬼箭羽已知化学成分及其裂解规律快速鉴定鬼箭羽药材中的化学成分。利用文献中鬼箭羽化学成分的分子式、相对分子质量、碎片离子等信息建立鬼箭羽快速识别数据库,依据化合物的精确分子质量、色谱保留时间、特征碎片离子等信息对已知成分进行验证;对于鬼箭羽中未知成分,通过总结同类化合物的质谱裂解规律,并查阅相关文献确定其相对分子质量、特征碎片离子、色谱保留时间等信息,并进行结构表征。实验共鉴定得到65种成分,包括36种黄酮类、4种酚酸类、7种三萜类、12种脂肪族和6种其他类成分,其中,有28种化合物是首次在鬼箭羽中发现。该方法可以快速、全面地分析鬼箭羽药材中的化学成分,可为鬼箭羽药材的质量控制研究奠定基础。