小壳体零件的工艺研究

本文简述了小壳体零件的特点,提出了以往生产中产品由于壁薄而废品率高的问题,由于零件设计和铸件毛料入手作以具体分析,改进了工艺方法,增加了加工余量,更改了毛料,实践证明,改进后的工艺方法,大幅度降低了加工中的废品率,提高了劳动生产率,满足了该零件的设计要求,为公司节省了大量生产成本。     

示准化学科行为互换性定律的创建

本文讨论了互换性定律的族系,研究了非训练行为不准确现象,讨论了行为互换性的需求,推论了行为互换性定律的存在,建立了行为互换性的概念,创建了行为互换性定律的命题及其数学模型,详述了定律的内涵,分析了行为互换性与其他互换性的关系,讨论了行为互换性定律的对象范围、互换类型、自身特点和作用意义,对行为互换性定律进行了验证分析,讨论了行为互换性定律的应用,并给出了应用例子。     

浅谈标准养蟹优化质量调整结构促进增收

通过农业标准化示范区建设项目的实施,促进了农产品质量安全水平的提高,延伸了产业链条,加快了全市农业产业化、现代化的进程,提高了农民的标准化意识,改善了生态环境,促进了可持续发展,为促进农业增效、农民增收起到了巨大作用。     

会计电算化与计算机技术的应用

随着社会的发展,科学技术的进步,计算机技术在各个领域中得到了广泛的应用。计算机技术在会计领域中发挥了重要作用,逐步建立起了会计电算化体系,充分发挥了计算机自动、高效、准确的优势,受到了会计人员的青睐,计算技术在会计领域中的应用提高了会计核算的准确性,提高了会计人员的工作效率,保障了会计工作快速、高效、高质量的完成。文章对会计中计算机技术的应用进行了探讨。     

基于VBA的千分尺证书记录系统

介绍了一种以VBA作为研发平台的千分尺证书记录系统。介绍了系统的结构,并详述了几个关键模块的设计和系统的防错功能,千分尺证书记录系统的研发,减轻了工作量,降低了劳动强度,杜绝了人为产生的偶然性失误,提高了劳动效率。     

继往开来更上一层楼

中国安装协会成立25周年了。25年来,随着我们国家的改革开放,市场经济的蓬勃发展,中国安装协会从成立到成长,走过了不平常的历程。历届理事会和秘书处的工作者,贡献了他们的聪明才智,书写了可歌可泣的篇章。协会已经成了安装企业交流合作的平台,成了企业和政府连接的通道,成了行业进步的集散地,成了安装企业之家。     

电子倍增CCD相机制冷绝热设计

对电子倍增CCD(EMCCD)相机制冷的必要性以及热电制冷器(TEC)的特点进行了说明,阐述了真空绝热的优势,分析了真空绝热失效条件,提出了真空绝热的难点及真空保持方案,分析了相机芯片发挥其性能所需的制冷温度,对制冷相机漏热途径进行了分析,计算了克服漏热所需的制冷功率,并设计了制冷绝热方案,对相机进行了稳态热分析建模,将多级热电制冷器进行了参数化转化并将其带入模型边界中,经过迭代拟合得到了相机杜瓦及芯片温度分布,分析了绝热制冷方案的可行性。     

掘进机在煤矿掘进中的有效利用

掘进机在煤矿的使用,改变了煤矿传统的掘进方式,提高了工作面的工作效率,质量、改善了工作环境,大幅度降低了劳动强度,解放了生产力。     

作业本中闪烁出孩子的希望之光

一叶知秋,一字知人。一滴水折射出了七彩之光,一本作业也同样闪烁出了孩子的勤奋,闪烁出了孩子的诚实,闪烁出了孩子的认真,闪烁出了孩子的聪明……闪烁出了一个热爱生命,热爱生活,积极向上的孩子。     

齿辊漏风的研究与治理

本文通过对齿辊漏风的研究与治理,解决了竖炉齿辊在检修后期严重跑风、漏尘的现象,消除了危险源,保障了维修点检修和操作人员的人身安全,保障了现场环境,延长了设备生产作业周期,提高了生产作业率,取得了良好的效果。     

Control of thermally induced elastic displacement of an isotropic structural plate bonded to a piezoelectric ceramic plate

Summary The present paper deals with a thermoelastic problem in an isotropic structural plate to which a piezoelectric ceramic plate of crystal class 6mm is perfectly bonded. It is assumed that the combined plate is subjected to a thermal load and then is deformed. In this case, we try to control the deformation of the isotropic structural plate by applying an electric potential to the piezoelectric ceramic plate. By analyzing the piezothermoelastic problem in the combined plate, we obtain an appropriate applied electric potential which alters the isotropic structural plate to a prescribed deformation. Finally numerical calculations are carried out for an isotropic steel plate to which a cadmium selenide plate is perfectly bonded, and the results are illustrated graphically.     

Behavior of laminated sandwich plates having interfacial imperfections by a new refined element

The static response of laminated sandwich plates having imperfections at the layer interfaces is investigated by a refined plate theory. The plate theory represents parabolic through thickness variation of transverse shear stresses, which are continuous at the layer interfaces and become zero at the plate top and bottom surfaces. In this plate model the interfacial imperfection is represented by a linear spring-layer. Moreover, with all these features of an accurate modeling, it involves unknowns only at the reference plane of the plate. To have generality in the analysis, finite element method is adopted. But any existing plate element cannot be used, as the plate theory demands certain inter-elemental continuity. Thus an attempt has also been made to develop a new triangular element. As there is no published result on imperfect sandwich plates, the problems of perfect sandwich plates and ordinary laminated plate with inter-laminar imperfection are used for validation.     

静电计检测微位移的原理和实验

该文叙述一种电容式微位移静电计测量方法。该方法中,静电计测量的可变电容两电极问电位差可直接转换为位移,其原理,最终公式和测试电路相当简单,而分辨率,预期能达到nm量级。用静电计—平行板电容测量装置对振动或冲击引起的微位移进行测量的实验结果验证了上述结论。     

波浪与弹性板作用的数值模拟

该文采用高阶有限元和边界元联合的方法求解波浪与弹性板的相互作用。其中流场采用边界元法求解,结构弹性响应方程采用基于Mindlin板理论的有限元方法求解,通过模态叠加技术实现了弹性板变形与流场相互作用的解耦。通过对一矩形板的计算,验证了该文方法与他人试验结果和数值模拟结果都吻合良好。利用这一模型进一步分析了波浪与弹性圆形板的作用问题,并对圆形板运动响应的收敛性进行了分析。     

Effect of a riveted wide patch on stresses in a cracked plate

We study the stress-strain state and limiting equilibrium of a thin plate with curvilinear cracks reinforced by a wide patch. The patch is arbitrarily located relative to the cracks and attached to the plate with elastic rivets. The boundary-value problem is reduced to a system of singular integral and integro-algebraic equations and this system is solved by the method of mechanical quadratures. Numerical analysis is performed for the case of a plate with one curvilinear or rectilinear crack reinforced by an elliptic patch. The stress intensity factors formed in this reinforced cracked plate and ultimate loads are determined for various geometric and physical parameters of the plate, crack, patch, and rivets. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 34, No. 1, pp. 37–46, January–February, 1998.     

An improved method for magnetic identification and localization of cracks in conductors

A SQUID magnetometer can be used to measure the magnetic field produced by flaws in a two-dimensional, conducting plate carrying a current. Identification of the flaw-induced magnetic field is difficult because of the large magnetic field associated with the edges of the plate and the current in the leads that connect the plate to the power supply. We have developed a technique by which the wire and edge fields can be cancelled prior to mapping the magnetic field. In this technique, a similar unflawed conducting sheet is placed adjacent to the flawed plate, with a connection between the sheet and the plate at one edge, and with the opposite edges of the sheet and of the plate connected to the two conductors of a coaxial cable. Thus, an applied current will flow along one conductor of the cable, across the cancelling sheet, cross into the flawed plate, return along the plate, and then return to the power supply along the other conductor of the coaxial cable. As a result of this geometry, there is no magnetic field from the lead-in wires because they are coaxial, and the magnetic field due to the edges of the plate is cancelled by the opposing magnetic field of the edges in the adjacent sheet. The extent of cancellation is determined primarily by the separation between the plate and the cancelling sheet, by the thickness of the plate, and by macroscopic inhomogeneities in their electrical conductivities.     

Simulation of vibration of inhomogeneous,loaded plates

Summary The Timoshenko-Mindlin type wave equation is derived for a plate which is inhomogeneous in material and geometric properties. A numerical analogue to this wave equation for a plate is presented and results of propagation studies of Gaussian and sinusoidal wavepackets along a plate reinforced by ribs of up to five times the thickness of the plate are discussed. Results are presented for an infinite plate supported by two ribs. The plate equation includes consideration of shear and rotary inertia, external loading and plastic-visco-elastic loss. A spectral analysis of the inhomogeneous plate equation is presented.     

Fingerprint input based on scattered-light detection

The principles of fingerprint imaging are based on scattered-light detection, and the technique is proposed for a compact input device. Light enters a glass plate from its edge and propagates inside the plate by repeating the total internal reflection at the boundaries with air. The ridges of a finger pressed onto the plate scatter the light, which then leaks out of the plate. This scattered light is imaged by an array of gradient-index optical fibers and an image sensor. A prototype sensor has been developed: The distance between the finger and the image sensor is 13 mm. The images obtained with this prototype clearly show not only the ridges and valleys but also the pores in the ridges.     

An adhesively laminated plate element for PZT smart plates

An adhesively laminated element taking into consideration peel stress is developed for a piezoelectric smart plate. In this novel finite element analysis formulation, a four node piezoelectric element is firstly derived, and an adhesive element of finite thickness with both shear and peel stiffness is sandwiched between two collocated four node plate elements to form an adhesively laminated element for a piezoelectric smart plate. In this framework of finite element analysis, because the displacement filed in this adhesively laminated element is continuous and a plate element is derived based on the Reissner–Mindlin plate theory, and thus it can be accurately applied to a thin or moderately thick host plate with bonded or debonded piezoelectric actuators and sensors. The formulation is performed for an isotropic host plate and a fiber reinforced laminate plate. Numerical results are presented to compare with those of the exact solutions for smart beams, and validate with the experimental results of the isotropic and composite host plates available in the literature. Using the present finite element analysis formulation, energy transfer stresses in the adhesive and equivalent forces induced in the host plate are investigated. The present formulation is demonstrated to allow debondings of piezoelectric patches and the debonding detection.The authors are grateful to the support of the Australian Research Council via a Discovery Projects grant (grant No: DP0346419).     

Squeeze film effect for the design of an ultrasonic tactile plate

Most tactile displays currently built rely on pin-based arrays. However, this kind of tactile device is not always appropriate when we need to give the illusion of finely textured surfaces. In this paper, we describe the squeeze film effect between a plate and a finger, and we use this effect to design an ultrasonic tactile plate. The plate is actuated by piezoelectric ceramics. Ultrasonic vibrations are thus produced and are capable of generating the squeeze film effect. This enables us to simulate variable friction on the surface of the plate. In order to identify the squeeze film phenomenon, this study considers the case where a finger, with a planar bottom surface and with epidermal ridges, is placed on a rapidly vibrating plate. The overpressure is calculated and the result enables us to assess the relative coefficient of friction as a function of the vibration amplitude of the plate. Based on this principle, and using both analytic and FE method studies, and given ergonomic and stimulation (squeeze film) requirements, we show that it is possible to design a tactile plate which is capable of giving programmable tactile sensations. We conclude by comparing the results obtained from our simulations with experimental results.