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.     

光学系统中心点亮度的计算

本文讨论了中心点亮度计算中的自动离焦问题,并证明本计算方法速度快、收敛效果好。     

美国教育博士与教育哲学博士之争的缘起和发展

美国教育博士（Ed．D．）学位与教育哲学博士（Ph．D．）学位之争由来已久。这既有复杂的历史原因,也与美国高等教育多样性、不同利益诉求、对学位教育质量关切等因素有关。从历史角度分析两种学位之争的缘起、演变及成因,并探讨其对发展我国教育博士专业学位教育的启示,具有积极的现实意义。     

高压和低压给水加热器安全阀的选用

分析了高压和低压给水加热器的结构、工作原理及旁路保护系统。给出了一种给水加热器安全阀排量的校核方法，并结合实例对安全阀进行了选型及计算。     

Advances in Optical and Electron Microscopy. Vol. 3. Edited by R. Barer and V. E. Cosslett

The production of vacuolated mitochondria and myelin figures can be markedly reduced with aldehyde perfusion fixation by perfusing a concentrated aldehyde solution before the conventional perfusate. A method is presented for accomplishing this with no practical time delay. Factors causing myelin figures and damaged mitochondria are discussed. Gum acacia helps prevent ‘washed-out’ cells and processes, and seems to aid myelin preservation. A clear solution is necessary for a good perfusion. Techniques for accomplishing this are presented. A concentrated formaldehyde solution perfused as a small volume immediately prior to the conventional perfusate causes alterations of the endoplasmic reticulum, including the subsurface cisterns, and an increase in numbers of spine apparatuses. Evidence is presented by using tubes of gelatin containing Schiff's reagent that formaldehyde is the fastest penetrating aldehyde but that it only fixes about half the distance it penetrates. Acrolein penetrates more rapidly than glutaraldehyde but fixes only as far as formaldehyde. Glutaraldehyde fixes as far as it penetrates.     

Generalized study of crank-rocker mechanisms driven by a d.c. motor Part I. Mathematical model

A mathematical model is developed for analyzing a 4-bar linkage driven through a speed reducer by a separately-excited d.c. motor. A set of nonlinear differential equations, governing the dynamic response of this system, is derived and converted to dimensionless form. This dimensionless form is described by newly defined linkage and drive parameters. It is believed that these parameters may find convenient use in estimating the overall behavior of motor-mechanism systems from performance graphs and guidelines which can be established by numerical study of typical cases.

The performance characteristics which are considered in this analysis are the steady-state speed fluctuation of the mechanism and its steady-state energy consumption as well as the time required for mechanism “start-up” and the energy consumption during start-up. Expressions are derived in a dimensionless form to represent these performance characteristics. In Part II of this paper, specific numerical examples are presented which relate the performance characteristics to the linkage and drive parameters for two different mechanisms.     

接触式波导旋转关节结构设计

讨论了波导关节的功能要求,基本结构形式,针对宽频段旋转关节提出了接触式的结构方案,并介绍了其详细结构。     

Professor H. Hashimoto,Hon. F.R.M.S

Book reviewed in this article: Thin Foil Preparation for Electron Microscopy. By P. J. Goodhew. An Introduction to the Optical Microscope. By Savile Bradbury. Techniques in Immunocytochemistry, Volume 3. Edited by G. R. Bullock and P. Petrusz. X-Ray Microanalysis in Electron Microscopy for Biologists. By A. J. Morgan. Self-Assessment in Histological Techniques. By John D. Bancroft and Brian T. Chalk. X-ray Microanalysis in Electron Microscopy for Biologists. By A. J. Morgan.     

Structure determination of tubular crystals of membrane proteins. III. Solvent flattening

Solvent flattening is considered to be a principal means for improving the data quality in X-ray crystallography. It could be equally effective for tubular crystals of membrane proteins imaged by electron microscopy because of the large empty space inside the tubes. However, tubular crystals are difficult objects for solvent flattening due to lack of electron diffraction amplitudes. Therefore, solvent flattening was used to align images more accurately and to improve the completeness of the data by reducing contributions of noise in the solvent (+ lipid) region. The methods developed were tested with the tubular crystals of Ca2+-ATPase embedded in amorphous ice. The improvement of the data quality was remarkable when solvent flattening was applied to many individual images before averaging. In this way, noises contaminated in the protein region by contrast transfer function were removed effectively. Solvent flattening was far more powerful than simple averaging described in Part II of this series (K. Yonekura, C. Toyoshima, Ultramicroscopy 84 (2000) 15).     

The curious mechanical euclid of William Whewell, F.R.S. (1774–1866)

The origin of the little known and virtually unread work of well-known polymath William Whewell, The Mechanical Euclid, (1837) seems ascribable to 19th century concern with the exact teaching of Euclid. The book probably initially stimulated the interest of Isaac Todhunter and Charles Dodgson who so loudly championed Euclid a generation later. The main purpose of this Note relates to their concern with Euclid and rigour.In writing about one of Whewell's books we do not neglect to observe that this year is the 200th anniversary of his birth.^†     

内燃机进气道的计算机辅助设计与制造

这里主要探讨了内燃机进气道的CAD/CAM,采用正向设计方法和逆向设计方法设计了进气道,并利用快速成型和数控机加工制作出气道的相关模型,通过应用发动机气道的CAD/CAM技术,缩短了气道的开发时间,减少了开发成本。