回转窑滚圈应力的测试方法研究

针对现阶段滚圈的强度分析主要依据简化模型下的有限元分析,导致不能真实反应滚圈的应力情况,且误差较大的问题.提出了通过用电测法来实测滚圈的真实应力,并了解滚圈的应力分布特性,这对于指导设计部门改进滚圈的设计,正确预测滚圈的寿命,具有重要的工程意义.     

SubLVDS驱动电路的设计

SubLVDS是一种超低压摆幅的差分信号技术,与传统的低摆幅差与信号技术相比,它具有更高的比特率、更低的功耗、更好的噪声性能和更稳定的可靠性.分析了SubLVDS的技术原理和优势,并给出了SubLVDS高速驱动电路的设计,其中采用MOS电容组成的高速降幅电路,利用负反馈和米勒补偿稳定共模点,采用SMIC 0.18 μm工艺,1.8 V的供电,最后实现摆幅为150 mV的、速度为1 Gbps、PSRR大于60 db的驱动电路.     

船舶ERP选型:集成性是关键

当前,信息化已经渗透到世界船舶工业的设计、生产、管理、服务等方方面面,其应用的深度与广度决定了行业综合水平的高低,成为大至一个国家的船舶工业、小至一个船舶企业能否在市场中生存和发展的关键.当造船业已经普遍意识到,以"信息化推动造船现代化"是中国造船工业追赶国际先进水平的最后机遇时,造船业的生存发展与IT厂商的策略几乎在同一时间不谋而合,在造船业竞争的搏奕中厂商的相助少不了.     

硬盘In-Drive 伺服刻写的设计及实现

硬盘的伺服刻写是整个硬盘产生的核心,其中伺服刻写中所产生的RRO是影响硬盘伺服质量的重要标志,并且RRO的大小决定着硬盘的功耗.采用传统的Media伺服刻写技术会产生很大的RRO,影响伺服信号的质量;而采用In-Drive伺服刻写技术可以避免传统伺服刻写中存在的问题.本文给出了In-Drive伺服刻写技术的详细设计方案和实现过程,对比Media伺服刻写方法,采用该策略实现的In-Drive伺服刻写,可降低伺服定位信号的波动及伺服位置的偏差,而且基准时钟写闭一般不超过4次.     

电火花加工技术的高效化研究进展

随着电火花加工技术的不断发展与成熟,进一步提高其加工速度成为人们不断关注的焦点.在纵观近年来电火花加工技术的发展现状及趋势的基础上,从电火花加工的基础理论研究、新型加工工艺及方法的采用、控制系统的自动化及智能化程度的不断提高、设备结构及其它辅助部件的改进等四个方面介绍了高效电火花加工技术的研究进展.     

建立科学的信息编码体系是信息化建设取得成功的重要保证

随着计算机网络技术的发展,信息化建设日益受到企业的重视,近年来很多企业加大了在这方面的投入,期望借助先进的信息化手段在生产经营管理上取得更好的效果.但是,从目前的情况来看,我国企业信息化建设的效果并不理想,很多企业并未从信息化建设中获得预期的回报.     

脱脂机组卷取张力自动优化设定技术的研究

经过大量的现场试验与理论研究,针对脱脂机组的卷取设备与工艺特点,充分考虑到后步工序的粘酷与松卷问题,在首次提出粘结与松卷综合控制目标函数的基础上,建立了一套完整的脱脂机组卷取张力自动优化设定技术,并将其应用到宝钢1220脱脂机组的生产实践中,取得了良好的使用效果,大大降低了粘结与松卷的发生率,创造了很大的经济效益,具有进一步推广应用的价值.     

数控设备操作失误及预防措施

随着数控的技术飞速发展和我国对数控技术投入的不断增加,拥有数控设备的企业越来越多,在数控机床的操作过程中由于操作不当而引起的事故不在少数,有的时候还会造成不可估量的损失.这样就要求数控设备的操作人员对常见操作失误有必要的了解.本文将和大家一起探讨数控机床操作常见问题及预防处理方法.     

高职院校机械实训中心管理探讨

就高职院校的机械实训中心的设备及人身安全、物流、工器具的使用、消耗材料的使用、教学管理等方面作了全面的阐述,结合实际总结了不同于生产企业的人流及物流的管理办法,并对一些有待于改善的存在问题提出了建议.     

电池的环保主义

现今社会,健康、环保已经成为全球的主旋律,人们渴望干净的地球,渴望健康的生命,渴望环保绿色的家园.腕表的设计、研发者们以及相关部门为了这个目标一直在不懈地努力着,为这个主题乐章奏出了美妙的和声.     

低温密封酸溶——高分辨电感耦合等离子体质谱法测定地质样品中50个微量元素的评价

The method based on the determination of trace elements in geological samples by sector high resolution inductively coupled plasma mass spectrometry with mixed acid digestion procedure has been evaluated. The evaluation show that the results of 29 elements including Li, Cr, Co, Ni, Cu, Zn, Ga, Rb, Y, Cs, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, W, Tl, Bi, Th and U are satisfactory; V, Sr, Nb, Mo, In, Sb, Ba and Pb are acceptable; Sc, Cd, Hf, Ti, Mn, Fe, Ge and Sn have of large deviations, Be, Ta, Zr, As and Se are worse.     

微波消解-电感耦合等离子体质谱法测定食品中18种元素

建立了食品中钠、镁、铝、钾、钙、钒、铬、锰、铁、镍、铜、锌、砷、硒、镉、锡、汞、铅的电感耦合等离子体质谱（ICP–MS）测定方法。样品经过微波消解,在线加入内标校正基体效应,通过修正方程校正质量数干扰,各元素校正曲线的相关系数均大于0.9995。对多种国家生物标准物质进行验证,测定值与标准值相符,相对标准偏差RSD（n=6）小于8.71%,加标回收率为71.8%～109.5%。     

The structure and function of auditory chordotonal organs in insects

Insects are capable of detecting a broad range of acoustic signals transmitted through air, water, or solids. Auditory sensory organs are morphologically diverse with respect to their body location, accessory structures, and number of sensilla, but remarkably uniform in that most are innervated by chordotonal organs. Chordotonal organs are structurally complex Type I mechanoreceptors that are distributed throughout the insect body and function to detect a wide range of mechanical stimuli, from gross motor movements to air-borne sounds. At present, little is known about how chordotonal organs in general function to convert mechanical stimuli to nerve impulses, and our limited understanding of this process represents one of the major challenges to the study of insect auditory systems today. This report reviews the literature on chordotonal organs innervating insect ears, with the broad intention of uncovering some common structural specializations of peripheral auditory systems, and identifying new avenues for research. A general overview of chordotonal organ ultrastructure is presented, followed by a summary of the current theories on mechanical coupling and transduction in monodynal, mononematic, Type 1 scolopidia, which characteristically innervate insect ears. Auditory organs of different insect taxa are reviewed, focusing primarily on tympanal organs, and with some consideration to Johnston's and subgenual organs. It is widely accepted that insect hearing organs evolved from pre-existing proprioceptive chordotonal organs. In addition to certain non-neural adaptations for hearing, such as tracheal expansion and cuticular thinning, the chordotonal organs themselves may have intrinsic specializations for sound reception and transduction, and these are discussed. In the future, an integrated approach, using traditional anatomical and physiological techniques in combination with new methodologies in immunohistochemistry, genetics, and biophysics, will assist in refining hypotheses on how chordotonal organs function, and, ultimately, lead to new insights into the peripheral mechanisms underlying hearing in insects.     

微波消解-电感耦合等离子体质谱法同时测定茶叶中42种元素

建立了电感耦合等离子体质谱法（IcP—Ms）标准模式和优化的碰撞池模式（CCT）结合同时测定茶叶中Li、Be、Mg、Al、V、Cr、Mn、Fe、Co、Ni、Cu、Zn、Ga、As、Se、Sr、Mo、Ag、Cd、Sn、Sb、Cs、Ba、Tl、Pb、Bi和16种稀土元素共42种元素的方法。样品经过微波消解,以Ge、In、Re为内标消除基体干扰,通过碰撞池技术消除多原子质谱干扰测定上述元素。对于所测元素校准曲线的相关系数均大于0．9990,回收率范围为90％-110％,相对标准偏差为0．22％-3．97％,大部分元素检出限均小于0．5μg·kg^-1。该方法简便、省时、准确、灵敏度高,适用于实际样品的检测。     

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Huge clusters of embryonic stem cells in human embryos: A morphologic study

Background: Nothing is known about huge clusters (HC) of embryonic stem cells (ESC) in human fetal organs (HFO). Aim: To know the status of HC‐ESC in HFO. Methods: Morphology and immunohistochemistry (IHC) in 32 HFO of 7–40 gestational weeks (GW). Results: HC‐ESC were seen in many HFO including central nervous system, spinal cords, spine, soft tissue, bone, skin, thyroid, lung, liver, pancreas, gall bladder, extrahepatic bile duct, adrenal, kidney, bladder, foregut, midgut, hindgut, female and male genital organs, and neurons. HC‐ESC's were composed of two populations depending on constituting cells. One were large cells with ample acidophilic cytoplasms with vesicular nuclei and nucleoli. The other were small cells with scant cytoplasm with hyperchromatic nuclei without nucleoli, resembling lymphocytes. The HC‐ESC were frequently showed neuronal differentiation. HC‐ESC were positive for NCAM, synaptophysin, NSE, chromogranin, PDGFRA, AFP, ErbB2, bcl‐2, KIT, MET. They were negative for CD45, CD3, CD20, EMA, CEA, CA19‐9, cytokeratin (CK) 7, CK8, CK18, CK19, MUC1, MUC2, MUC5AC, and MUC6. The mean Ki‐67 labeling index (LI) was 13% ± 7%. HC‐ESC showed a little glycogen but lacked mucins. These HC‐ESC were seen in 7–25 GW, and they were rarely seen in 26–40 GW. Conclusions: The morphology, IHC, and ontogeny of HC‐ESC were described. Microsc. Res. Tech. 77:825–831, 2014. © 2014 Wiley Periodicals, Inc.     

Epibiotic microorganisms on copepods and other marine crustaceans

Although the occurrence of microbial (algal, protozoan, bacterial, and fungal) epibionts on marine crustaceans and other invertebrates has been documented repeatedly, the ecological context and significance of these relationships generally are not well understood. Recently, several studies have examined the population and community ecology of algal and protozoan epibionts on freshwater crustaceans. Even so, the study of microbial epibionts in aquatic environments is still in its infancy. In this review, we summarize associations of microalgae, protozoans, and bacteria with marine crustaceans, especially copepods. We note differences and commonalities across epibiont taxa, consider host-epibiont cycling of nutrients, generate hypotheses relevant to the ecology of the host and the epibiont, and suggest future research opportunities. Microsc. Res. Tech. 37:116–135, 1997. © 1997 Wiley-Liss, Inc.     

Assessment of PM-EDM cycle factors influence on machining responses and surface properties of biomaterials: A comprehensive review

Powder mixed-electro discharge machining (PM-EDM) is recently evolving machining technique which can simultaneously remove and modify the machined surface through thermo-electrical process. It is a modified form of EDM in which the conductive powder elements are added in the dielectric liquid to enhance machined surface characteristics and machining responses. The commonly used biomaterials such as 316L stainless steel, Ti-based alloy, Ni–Ti, Mg alloy, and Co–Mo–Cr alloy have excellent mechanical characteristics while the biofunction of these materials are not in satisfactory level. Due to higher hardness, brittleness, and heat resistant natures of the biomaterials, it is very challenging to machine them with conventional machining. Both the system efficiency and modified surface properties depend on the associated electrical and non-electrical factors of PM-EDM cycle. This review focuses on the influence of process factors such as current, pulse duration, tool-polarity, duty cycle, potential voltage, types of liquid, and added powder concentration on performance outputs including material removal and tool wear rate, coating thickness, coarseness, microhardness, coating adhesion bonding, biocompatibility, and resistant to corrosion. This study also discusses influence of various powders on machining and modified surface characteristics of biomaterials. The future research scopes and challenges of PM-EDM process are included in this study thoroughly.     

A review of ultrafine particles as antiwear additives and friction modifiers in lubricating oils

This paper gives an overview of developments in the use of ultrafine particles in lubricating oils to reduce wear and friction. Work on several types of particles, such as graphite, MoS₂, PTFE, BN, fullerene, and Cu, as well as more novel and unusual particles used as lubricant additives, is reviewed. The paper summarises the results of a number of workers in this field. The tribological mechanism by which ultrafine particles operate is considered, and some conclusions, including possible future directions for research, are drawn.     

碳纤维山地自行车架生产工艺的发展现状与发展趋势

碳纤维自行车架具有质量轻、强度高、刚度好、抗振性强等优点,是竞技山地车架发展的趋势。目前,碳纤维山地自行车架的生产多以RTM工艺为基础,国内外在设计和生产方面进行了大量创新,研究出诸如OCLV、IsoTruss、IsoGrid和ExoGrid以及ALMA、OIZ和Arantix等专利技术和产品,也暴露出了一些问题。未来几年,碳纤维山地自行车架的生产工艺在吸收、引进各种先进技术的同时,将有望进一步提高整体性能和降低生产成本。