光电光栅刻划机讯号转换试验

使用衍射光栅控制光栅刻划机分度的方法早已成功^[1].此种刻机的刻程,受限于所用衍射光栅的长度.较长的衍射光栅是很难得到的,能否用较短的衍射光栅来控制刻机走较长的刻程呢?这是一个很吸引人的问题.我们设计了一种较简易的方法,做了“讯号转换”试验.成功地划出了当中经过讯号转换的光栅.     

凹面衍射光栅刻划机

长春光机所于1979年研制了一台凹面光栅刻划机,可刻划光栅面积为70×90毫米²,每毫米可刻划600、1200、2400条线的凹面光栅。1980年末刻出半径为0.35米的Ⅰ型试用光栅,1981年刻出半径为1米的Ⅰ型试用光栅。     

建所以来衍射光栅工作介绍

引言长春光机所衍射光栅的研究工作是1958年开始的。经二十多年的努力建立了一整套光栅刻划机设计、加工、装调技术,制造了4台三种类型的光栅刻划机,并向国内七个光学仪器厂推广,建立了光栅检验设备及六项光栅性能指标的检验方法。掌握了从近紫外、可见到近、中红外光栅刻划的基本技术。建立了光栅复制工艺。已向国家提供原刻光栅及复制光栅近百个品种,一千余块。近年来,又开展了大光栅机、凹面光栅机构、全息光栅及其它光栅的研究和设计工作。下面就几个方面分别介绍。     

红外宽波段光栅调频激光器光栅和刻划机

本文介绍了自制红外光栅刻机的主要结构,恒温防震等环境要求的解决,刻划刀的设计与安装,并介绍了用该刻机刻制的光栅经检验达到日本同类光栅的技术水平。     

平面衍射光栅刻划机

目前,绝大部分使用的平面衍射光栅,是在光栅刻划机刻出的光栅上复制出来的复制光栅.因此,由光栅刻划机刻出的光栅叫原刻光栅或母光栅.光栅刻划机是制造光栅的最主要设备.由于衍射光栅有精度要求高(一般在0.01微米数量级),刻划周期长(一般约五昼夜)的特点,光栅刻划机以及机器所处的条件必需与之相适应.我们已设计制造成功四台平面衍射光栅刻划机,机器所需恒温、隔振条件也已解决,现正着手设计第五台光栅刻划机,下面谈几点体会.     

任意等分圆光栅的刻划

本文介绍了用简单的BASIC语言程序对任意等分圆光栅的分度进行计算,以及具体的调整刻制方法,从而在未任何附加装置的圆刻机上刻制出任意等分圆光栅,且保证了一定的刻划精度。此法简单、易行,而且同样适用于任意等分度盘的刻划。文末附有BASIC程序。此外,还简单介绍了微机控制圆刻机进行任意等分刻划的原理。     

美国大型光栅刻划机情况简介

从文献报道可知,美国的大光栅刻划机有威尔逊天文台的两台,麻省理工学院的三台,纽约州立大学正在研制中的一台。现将我赴美短期考察,了解到这6台刻划机的情况介绍如下。威尔逊天文台的两台刻划机,放在加利福尼亚州帕萨迪纳市内威尔逊天文台办公楼的地下恒温室内。大的一台叫 A 机,可刻光栅宽到610毫米,每毫米刻线300到900条。纯机械结构,工作台和刻桥均用双 V 形滑动导轨,丝杠长约800毫米,直径约70毫米,螺距2毫米,蜗轮1200齿。驱动部分有两套曲     

衍射光栅自刻法

本文介绍以被刻光栅本身作为分度基准刻划长衍射光栅的新方法:先用原基准信号控制机器,在一个长毛坯的前端刻出一段光栅,用这段光栅构成新的干涉仪以产生“自刻信号”,然后再以自刻信号控制机器接着刻划光栅后面的部分。还分析了转接误差对自刻光栅的影响,得出刻划长度和误差累积的关系。简单介绍了实验方案、装置、实验结果等。所刻样品光栅的衍射波阵面干涉条纹在转接处看不出错开和弯曲,实测分辨本领达到理论值的90%(半宽法)。     

机械刻划层分结构铝膜刀具磨损研究

掌握机刻光栅刀具磨损机理是稳定制备大面积光栅的关键,由镀制工艺决定的具有层分结构铝膜是机刻光栅的首选膜坯。为获取光栅机械刻划过程中层分构铝膜对金刚石刻划刀具磨损影响规律,首次开展层分构铝膜力学性能测试与刀具刻划磨损规律研究,采用纳米压痕实验测得层分构铝膜硬度与弹性模量分别为0.48 GPa与65.2 GPa,满足Hall-Petch强化理论。据此,首次运用Deform 3D有限元分析软件建立层分构铝膜模型,将刻深位置设置在铝膜层分界面位置,分别对刻深在2μm与4μm的单层与4层铝膜进行刻划仿真后发现,分层膜界面对于其应力传递影响作用明显,且刻深突破第一、二层铝膜界面时,该界面对于应力传递的阻碍作用消失;不同刻深刻划单层和4层铝膜时刀具磨损形式与磨损部位大体相同,但刻划4层铝膜时刀具磨损较小,与后续机刻试验结果相符。     

0.2秒圆刻机的基本原理

本文根据作者所搜集到的资料综述了圆刻机的发展历史,在漫长的发展过程中大体经历了抄录刻划、机械刻划和光电刻划三个阶段,中国古代曾对刻划技术的发展作出过重要贡献。列表说明了世界上圆刻机生产及研制现状。本文介绍了长春光机所近十几年来研究成功的一种光电圆刻方法,它的特点是:利用传统的机械方法进行分度粗定位,而后再用光电伺服控制对误差进行微量校正。     

A new approach to generation of ruled surfaces and its applications in engineering

Based on the Study displacive theory that there is a one-to-one correspondence between an oriented straight line in three-dimensional Euclidean space (E ³) and a dual point on the surface of a dual unit sphere (DUS) in three-dimensional dual space (D ³), this paper presents a new methodology for the generation of ruled surfaces by planning (fitting or interpolating) the motion locus of a point on the surface of a DUS and discusses its applications in engineering. Some geometric problems and an optimal generation model for ruled surfaces are dealt with in detail. The correctness and effectiveness of this methodology are illustrated by examples and application in practice.     

A Study of Characteristics of the Controlled Oil Leakage of Valve-Stem Seals for Automotive Engines

It is well known that the valve-stem seal has been used for the valve-stem application of automotive engines, and influences the lubricating status between the valve stem and a valve guide. The valve-stem seals are important in controlling consumption of lubricating oil for engines and in preventing air pollution.

It is necessary that valve-stem seals have stable controlled oil leakage characteristics, Q (cm³/s), relative to variables such as oil viscosity, shaft speed and shaft-surface roughness. In this paper, characteristics of the controlled oil leakage on valve-stem seals have been discussed by applying an inverse problem of hydrodynamic lubrication.     

Measurement of oil film thickness in big-end bearings and its relevance to engine oil viscosity classifications

Minimum oil film thickness MOFT measurements have been carried out in big-end bearings of V6 and in-line four-cylinder gasoline engines during engine operation. MOFT decreases with increasing crankshaft speed above 2000 r/min. The most severe practical steady-state operation is high-speed cruising. Maximum shear rates are in the region of 10⁷s⁻¹ at 4000 r/min. the dynamic viscosities at a shear rate of 10⁶s⁻¹ correlate significantly better with monograde MOFT data than with multigrade data; the correlation parameters for mono- and multigrade data are also significantly different. Although the dynamic viscosity measurement correlates with multigrade data better than the low-shear rate kinematic viscosity, the differences are not always significant at the 95% confidence level. Some other rheological parameter or combination of parameters may be better than either kinematic or dynamic viscosities.     

The electron-beam induced monomerization of di-p-anthracene

The electron beam stability of di-para-anthracene has been investigated with regard to the study, in situ, of the mechanism of photodimerization of anthracene and related materials. It is found that the electron beam converts di-para-anthracene to anthracene, the process taking place in a single crystal to single crystal manner. Electron doses greater than 6.0 × 10^?5 C mm^?2 result in a diffraction pattern corresponding to the anthracene lattice.     

Investigation of properties of electrochemically synthesizediron oxide nano‐powders

Nano‐sized powders of iron oxides have been synthesized electrochemically at temperatures in the range of 295–361 K, and current densities in the range of 200–1000 mA dm^?2. The structure and morphology of the powders were investigated by X‐ray diffraction and scanning electron and transmission electron microscopy techniques. Their infrared absorption spectra, specific heat C_p(T) and magnetic susceptibility χ(T) temperature dependences are also determined. The obtained powders consist of two phases, each possessing distinguished characteristics: the one formed of large plates and the other of whiskers. By appropriate adjustment of the synthesis conditions, it is possible to change features and relative abundances of the two phases, and that way to control morphology and other powder properties. Relaxation and transformation of the phases under external influences was also investigated, and the optimal procedure for preparation and stabilization of iron oxide nano‐sized powders with desired characteristics was established.     

Physical properties and testing of organosilicon esters for their applicability as synthetic lubricants

The constantly growing needs of the operational parameters of machines and engines, especially for aeronautical use, have brought about greater demands on lubricating oils. Various synthetic materials have been used since the Second World War,¹ in increasing quantity, as substitutes for mineral based oil: esters from organic alcohols and mono- or dicarboxyl acids are among the most widespread. Quite a different type of synthetic oil is organosilicon compounds, known as ‘silicones’. This paper reports experimental data for a group of silicon compounds examined in comparison with other materials normally used as bases for synthetic lubricants.     

Bearing Retainer Material for Modern Jet Engines

Modern jet engines require bearing retainers that can provide reliable service under stringent and unusual conditions. In current commercial transports, these engines commonly operate at 1.5 × 10⁶ DN for 12000 hours or more between overhauls, and in military applications, the cage and bearings are required to retain its integrity when the oil is lost for up to one minute while at foil power. Standard bronze retainers with lead plate over silver plate have proven inadequate to meet these requirements. To find a more suitable retainer, candidate cage materials and coatings were evaluated in a test rig simulating engine conditions. A silver plate AMS 6415 cage material was found capable of surviving a program which comprised 50, one minute, oil cutoff cycles. An additional program was conducted to optimize the Ag-plate coating thickness which was established as being 0.001 to 0.002-inches thick. Subsequent engine evaluation of this silver plated steel retainer verified the rig test results. This material combination is now used in production engines in both commercial and military aircraft.     

Some single zone scavenging models for two-stroke engines

The paper proposes a simplified version of the various multi-zone models which have been proposed for diesel engines to represent the pure air, mixing and residual zones of the real process, with or without short circuiting. [Benson, Int. J. Mech. Sci.19, (1977); Baudequin and Rochelle, Proc. Instn Mech. Engrs.194, (1980); Chen and Wallace, SAE paper 871657 (1987).]These models use flow coefficients defining the division of the air-flow entering, and of the outflow leaving, the cylinder between the various zones. The choice of these coefficients is rendered more difficult by the absence of direct experimental evidence.The present model in which the cylinder contents are represented by a single zone uses two coefficients which directly define the nature of the scavenging process.

1. (a) The fraction x of the initial cylinder contents subject to displacement scavenging during phase 1, and

2. (b) the short circuiting fraction y of the entering air during the mixing dominated phase 2.

Single zone representation of the cylinder contents is made possible by the use of a residual filter during phase 1 and an air filter during phase 2, the former allowing pure residuals, and the latter pure air, to be exhausted while the cylinder gases are undergoing a pure mixing process.The model is applied to typical scavenging situations for uniflow, cross flow and loop scavenged diesel engines, both for the idealized isobaric, isochoric case and for the ‘real’ engine using a full cycle simulation program.     

A method of the determination of a developable ruled surface

Using dual vector calculus, a method of determination of a developable ruled surface is presented. The dual vectorial expression of a developable ruled surface m(t, u)=p(t)+ux(t), p(t) is called the base curve of m(t, u), obtained from the coordinates and the first derivatives of the base curve.     

Combustion and emissions of the diesel engine using bio-diesel fuel

The combustion and heat release of engines using diesel fuel and bio-diesel fuel have been investigated. The results illustrate that the combustion happens in advance and the ignition delay period is shortened. The initial heat release peak declines a little, the corresponding crankshaft angle changes in advance, and the combustion duration is prolonged. The economic performance and emission features of diesel engines using diesel fuel and bio-diesel fuel are compared. The results also show that the specific fuel consumption of bio-diesel increases by about 12%. The emissions, such as CO, HC, and particulate matter decrease remarkably whereas NO _x increases a little. __________ Translated from Journal of Jiangsu University (Natural Science Edition), 2006, 27(3): 216–219 [译自: 江苏大学学报(自然科学版)]