KL-15A型制氧制氮车的研制

简述了KL 15A型制氧制氮车的设计方案、设备布局、试验和试用情况 ;分析了此制氧制氮车的工艺流程及气氧、液氧、气氮和液氮四种工况的实现 ;并与KL 15型制氧制氮车的性能指标进行了简单比较 ;最后介绍了KL - 15A型制氧制氮车具有的技术特点     

提高工业铂热电阻检定效率的技术措施

工业铂热电阻根据其制造时接线方式的不同可以分为二线制铂热电阻、三线制铂热电阻、四线制铂热电阻。二线制铂热电阻虽然结构简单,但测量准确度较低,已较少使用。目前,在温度测控领域普遍采用的是三线制铂热电阻。四线制铂热电阻一般直接与高精度数字多用表、测温电桥等电测设备连接使用,用于高精度测量领域。     

浅谈事业单位记账基础的改革

权责发生制和收付实现制是会计的两大记账基础,在我国事业单位主要采用收付实现制.为了全面、客观地反映会计信息,由目前实行的收付实现制改为权责发生制,已是十分紧迫和必要的.     

采样和制样过程中应注意的问题

本文分析了商品煤采样和制样过程中应注意的事项,提出在采样过程中应注意合理布置采样点、保证足够的子样数目和子样质量、正确选择采样工作等事项,在制样过程中应注意制样前的准备工作、缩分等制样过程应规范、应榆验煤样制各的精密度等事项。     

购买流程客制化对在线零售品牌信任影响路径

通过相关文献回顾和对在线购买顾客的实际调查,提出了线上线下不同购买流程阶段的客制化应当包括信息交互客制化、交易客制化和履行客制化,并实证考察了购买流程客制化通过顾客感知控制对品牌信任的影响机理.对433份问卷数据的结构方程模型分析表明,信息交互客制化、交易客制化、线下履行客制化显著正向影响顾客对购买流程的感知控制;购买流程客制化通过感知控制的中介作用,影响顾客对在线零售商的品牌信任.明确了在线零售商线上线下购买流程的相互关系,并提出了通过购买流程客制化获取顾客品牌信任的策略建议.     

用透明正片翻制底片的方法

翻制底片有三种方法,即用照片翻制底片,用透明正片翻制底片和用底片复制底片。根据制片单位所具有的条件以及制底的不同情况可选择采用。三种方法的共同之处都是翻制底片,不同之处在翻制底片的质量上。用透明正片翻制底片的灯光是采用灯箱,光源是从透明正片的后面通过透射光,而与照片翻制底片的反射光是不同的。正因如此,用透明正片翻制底片的质量特点是透明度好、层次丰富、清晰度高。与用照片翻制底片的道理基本上是一样的,但是在翻制设备条件、操作方法、使用原材料等等方面有区别。本文中对透明正片翻制底片工作程序及其方法简述…     

多晶硅表面制绒技术研究现状

光伏产业在新能源发展规划中占有重要地位,目前多晶硅太阳能电池已经成为太阳能电池市场主流。硅片表面绒面的质量对太阳能电池转换效率有重要影响,多晶硅表面制绒技术也越来越受到世界各国的重视。掌握多晶硅表面制绒技术的原理及特点对提高表面绒面质量十分重要。首先分析多晶硅表面制绒的技术要求,随后根据不同的技术原理,依次对干法制绒技术、湿法制绒技术以及掩膜制绒技术进行综述,详细分析不同制绒技术的技术特点并阐述其应用实例,随后从绒面质量、制绒效率、成本以及环保性等方面对多晶硅制绒技术进行评述,最后对多晶硅制绒技术的发展趋势进行预测。     

量和单位系列讲座 第二讲 量制 量纲 计量单位及单位制

一、量制在科学技术领域,使用着许多种量,所以就出现了不同的量制。"彼此间由非矛盾方程联系起来的一组量"称为量制,也可以指彼此间存在确定关系的一组量,或是在科学技术领域中约定选取的基本量和与之存在确定关系的导出量的特定组合。量制通常以基本量符号的组合作为特定量制的缩写名称,如基本量为长度(l)、质量(m)和时间(t)的力学量制的缩写名称为l、m、t量制。     

电解制样在不锈钢金相检验中的应用

使用电解抛光仪对奥氏体不锈钢、铁素体不锈钢、马氏体不锈钢等不锈钢进行了电解制样,对各种不锈钢的电解制样参数进行了摸索,以满足不锈钢不同金相检验项目的高效快速检测,并对影响电解制样的因素、电解制样的常见缺陷及纠正方法、电解制样存在的问题及注意事项等分别进行了分析。结果表明:通过选择适当的电解参数和电解液使用电解制样方法可以获得较好的制样效果;如果电解参数或电解液选择不合理,所制备试样表面就会出现氧化膜、腐蚀坑及过腐蚀等缺陷;另电解制样还存在不能用于非金属夹杂物检验试样的制备、存在倒边以及所制试样碳化物检验级别稍高等不足;电解制样过程中还应注意要对电解液不断地进行搅拌,避免夹具浸入到电解液中,及时更新电解液等事项。     

影响滚筒反力式制动检验台制动力标定的几个问题

分析了影响滚筒反力式制动检验台制动力标定的几个问题,包括:标定过程中制动力单位使用的问题、制动力标定软件插入点使用的问题、制动力标定杆杆倾斜的问题、制动力标定与检测不能同步的问题、制动力标定过程中的倍率问题,并给出了解决方法,供相关人员参考。     

Analytical approximations to the viscous glass-flow problem in the mould-plunger pressing process, including an investigation of boundary conditions

Industrial glass is produced at temperatures above 600°C, where glass becomes a highly viscous incompressible fluid, usually considered as Newtonian. In the production two phases may be distinguished, namely the pressing phase and the blowing phase. This study will be concerned with glass flow in the pressing phase, which is called thus because a blob of fluid glass (called a gob) is pressed in a mould by a plunger, such that the glass flows between mould and plunger, in order to obtain the preform of a bottle or jar, called a parison. In the blowing phase (not considered here) the parison is subsequently blown into the final shape of the product. By application of the slender geometry of mould and plunger and a cylindrical symmetry, a form of Reynolds's lubrication flow equations is obtained. These equations are solved by utilizing the incompressibility of the glass, by which the flux at any axial cross section is determined for prescribed plunger velocity, leading to analytical results in closed form for velocity field and pressure gradient. The glass level is implicitly defined by the integral over the varying volume which is to remain constant. The pressure may then be determined by integration. Special attention is given to the required boundary conditions. It is known that, depending on several problem parameters like temperature, pressure, and smoothness of the wall, the glass flow slips, to some extent, along the wall. Therefore, this study includes a general formulation of the boundary condition of partial slip in the form of a linear relation between shear stress and slip velocity, also known as Navier's slip condition. The coefficient of this relation, a positive number, may vary in our solution with axial position, but depends on the problem and is to be obtained from (for example) experiment. Two special cases, which seem to be relevant in practice, are considered as examples: (i) no slip on both plunger and mould; (ii) no slip on the mould and full slip (zero friction) on the plunger. The results are compared with fully numerical (FEM) solutions of a Stokes-flow model, and the agreement is good or excellent. Since in any practical situation it is not the plunger velocity which is prescribed, but (within practical limits) the force applied by the plunger, the problem of a prescribed plunger force has also been investigated.     

专利产品--HGL-150滑阀真空泵的研制

介绍了极限压力处于国际领先水平的专利产品HGL－150滑阀真空泵的研制情况，对全面提高滑阀真空泵综合性能的方法进行了探索，并把HGL－150滑阀真空泵的性能与国内外同类产品进行了对比。     

滑阀式真空泵排气系统抗性消声结构的研究

滑阀式真空泵排气系统的气流通道截面具有多次突变的特点，利用这个特点可以进行抗性消声设计。理论和试验都表明，合理地设计滑阀式真空泵排气系统扩张比、扩张室长度以及适当地利用插入管，可以有效的降低滑阀式真空泵的低频噪声。经过对H150型滑阀式真空泵的初步试验，取得了降低噪声9dBA的效果。     

柱塞弹簧折断失效分析及其对策

对航空燃油泵柱塞弹簧长期存在的折断失效原因进行了较为全面系统的分析，通过提高原材料冶金质量，改进柱塞弹簧制造工艺，采用超声波检查弹簧珠表面缺陷等手段提高柱塞弹簧质量，彻底地解决了其折断失效问题。     

Electrical simulation of contact stresses for an eccentrically loaded paraboloid of rotation entering an elastic half-space

A method is proposed for solving three-dimensional contact problems by electrical simulation. There is an analogy between the equations describing the reactive-pressure distribution over the contact area and the charge at the surface of a current-carrying plate. A method is given for determining the indentation by a nonplanar plunger driven by an eccentric load and entering an elastic half-space, for which a special electrical simulator is used. This device is briefly described. The error of the method is estimated. A detailed example is considered for a plunger in the form of a second-degree paraboloid of rotation. The inclination of the plunger affects the reactive-pressure distribution on the contact area. Pressure patterns are given for several angles of inclination.Translated from Problemy Prochnosti, No. 1, pp. 57–60, January, 1992.     

柱塞套开裂原因分析

一批柱塞套在磨削加工后发现其中有十几件出现裂纹。采用宏观分析、化学成分分析、金相检验及硬度测试等方法对开裂柱塞套进行了分析。结果表明：柱塞套在淬火加热过程中局部过热,引起显微组织及奥氏体晶粒粗大,降低了材料的强度,导致在柱塞套淬火过程中引起淬火裂纹。最后提出了改进建议。     

An instrument for measuring the voltage standing-wave ratio of a generator

Conclusions The comparison results confirm the relatively high accuracy of measurement of the standing-wave ratio by means of the above instrument.The instrument can also be used for matching the generator when its potput is insufficiently decoupled and there is a possibility of the results being distorted by the reaction of the adjustable plunger on the generator. For avoiding this reaction another hole should be made in the body of the plunger, and an absorbing sliding wedge placed in it. The protruding wedge lowers the standing-wave ratio of the instrument and decreases its effect on the generator. When the instrument is used for accurate measurements of the standing-wave ratio the absorber is pushed inside the plunger and produces hardly any effect on the operation of the instrument.     

注塑机导柱断裂原因分析

注塑机导柱使用约1a（年）即发生断裂失效。采用化学成分分析、显微组织观察、裂纹及断口特征分析等方法对注塑机导柱失效断裂的原因进行了综合分析。结果表明,导柱材料误用是造成导柱断裂的主要因素,导柱的断裂属于多源疲劳断裂。     

Handling hostile environments at a stroke

Premature seal failure in reciprocating pumps present users with both operational and maintenance problems. In general, standard elastomers in the plunger packing fail due to frictional heat and abrasion generated by the mechanical movement of the plunger. In this article Fred Pipper of Utex Industries, describes the development and testing of a new nitrile-based elastomer system for sealing reciprocating pumps, which possesses high wear and anti-abrasion properties.     

滑阀真空泵性能再探

本文对滑阀真空泵的性能作了进一步研究,提出了活动密封的新概念,研究了排气速度、排气流道大小和形状对泵的性能的影响,阐明了滑阀泵噪声机理研究中的又一个新噪声源——导轨对滑阀杆的撞击,分析了泵的噪声传播和屏蔽,讨论了减少摩擦功的途径。