照相机的快门及其发展（上）

照相机快门是使胶片获得合适曝光量的时间控制机构。在照相机发展早期,由于感光材料感光度很低,所需曝光时间很长,采用装上、卸下镜头盖来控制曝光时间。随着感光材料感光度的增高和拍摄要求的不断提高,逐步形成了我们所说的现代意义上的快门,它是控制曝光时间长短的机构。快门在照相机中的作用主要有三：控制胶片曝光量,即通过控制曝光时间的长短和光圈装置一起保证胶片适正曝光;控制拍摄运动物体时的成像模糊量,快门安置在成像光束中间,保护已曝光或来曝光的胶片不至漏光或重复曝光。按快门的作用来说,它似乎可以安置在通光光束…     

柯达专业T-MAX黑白胶片T400CN

柯达公司生产了一种新型专业黑白照相胶片,并且以１３５２４,１３５３６和１２０三种规格投放市场。该胶片属专业胶片ＴＭＡＸ系列产品,感光度ＩＳＯ４００。使用该胶片获得的影像,在ＥＩ４００曝光条件下曝光,与大多数传统的感光度ＩＳＯ１００黑白胶片相比,...     

国外彩色反转片、彩色胶卷、彩色相纸产品简介(上)

一、彩色反转片 1.K-14加工柯达克罗姆25专业片: 系日光型胶片,在1/10000～1秒范围内曝光时,不需要滤色或曝光校正。曝光时间不宜大于10秒。该胶片反差适度、颗粒细腻、清晰度高。通常使用的是35毫米胶片。     

柯达黑白胶片——T-max100和T-max400的评介

1986年柯达公司在西德科隆摄影博览会上推出两种高质量的黑白胶片T-max 100和T-max 400。这两种胶片第一次采用了“T-颗粒”技术。使用一般黑白显影液冲洗之后,与其它类似的胶片相比,影像质量最佳。据柯达公司介绍,T-max 100的曝光指数为ISO100,但它的影像要优于曝光指数为ISO32的柯达FX 胶片。T-max400的曝光指数为ISO400,但它的影像质量却优于曝光     

航空胶片感光度及其应用

在航空与航天摄影中正确曝光是保证获取底片最佳影像质量的基础,而航空胶片感光度则是正确曝光的一个主要因子。目前,我国航空摄影测量与遥感部门使用的航空胶片种类繁多,采用的感光度制也不相同,如柯达航空胶片采用AFS 制,而国产航空胶片采用苏联ГОСТ制。在航空摄影     

摄影曝光原理纪要(一)

若要实实在在的掌握摄影曝光技术,必须对一些光度学名词概念有些了解…弄懂感光材料(胶片、相纸与电子感光元件)的感光特性,才能弄懂曝光的基本原理;曝光准则A:"景物的实际曝光范围应落在胶片的有效感光范围之内",曝光准则B:"照片上主体影像的影调应与主体景物相符";各种测光装置(曝光表)及其用法;通过实际拍摄积累经验,才能熟练掌握曝光技术。     

汽巴克罗姆—银漂胶片

银漂胶片在乳剂中加入的是高纯度偶氮染料。曝光后冲洗时,曝光部分的染料被洗掉,留下未曝光部分的染料,形成反转影像。银漂胶片的特点是彩色鲜艳、饱和、色牢度好。同时,涂层中的染料可降低光散射,故清晰度也好。这种胶片可用于放大巨型照片,亦可直接扫描分色作制版原稿,以及直接拍摄工程图等。     

柯达新产品

柯达一步摄影彩色胶片PR10已于1979年秋上市,此胶片与柯达原生产的一步摄影胶片包同样适于专业摄影和科技领域使用。胶片拍摄之后离开摄影包约30秒即可得到照片。从曝光到得像也不过90秒。日光曝光指数(EI)为150(即1/100秒的拍摄时间,室温显影)。     

摄影经验三则

1.防止彩色胶片受潮拍照时,当胶片防潮盒打开之后,胶片会很快同外部条件接触,因此胶片应立即曝光冲洗。曝光后没有立即加工、待冲洗的胶片更加要防止潮湿空气,胶片最好放在装有螺丝柱或密封坚固的金属储器中,并加上胶带封口。金属存储器关闭之前,放入小布袋,硅胶作干燥剂,10卷135胶片可用60克硅胶。如发现硅胶颜色变淡,可将硅胶取出在150度火焰酒精灯上烘烤,由淡色转为蓝色,冷却后再继续使用。     

摄影曝光原理纪要（五）

若要实实在在的掌握摄影曝光技术,必须对一些光度学名词概念有些了解,弄懂感光材料（胶片、相纸与电子感光元件）的感光特性,才能弄懂曝光的基本原理。曝光准则A：“景物的实际曝光范围应落在胶片的有效感光范围之内”。曝光准则B：“照片上主体影像的影调应与主体景物相符”。各种测光装置（曝光表）及其用法。通过实际拍摄积累经验,才能熟练掌握曝光技术。     

动能定理的应用分析

通过对动能定理、功能原理和机械能守恒定律的简明推导,总结出动能定理、功能原理和机械能守恒定律三者之间的相互关系及各自的应用条件。重点阐述了动能定理与机械能守恒定律应用的区别。     

爆炸压实工艺参数对钢管能量与变形的影响

为了指导研究爆炸压实工艺参数的选择,通过改变爆轰速度与装药厚度来改变爆炸冲击能,重点研究爆炸压实工艺参数对钢管能量与变形的影响.研究表明:当其他工艺因素相同、仅爆轰速度不同时,将导致爆轰压力、钢管壁速度、爆炸冲击能、粉末压实能等显著不同,但钢管的变形与能量却几乎不变;当采用爆轰速度极高的黑索今炸药时,由于爆轰压力与爆炸冲击能过高,导致钢管头部被切掉;对硝酸脲炸药而言,随着装药厚度与炸药/钢管质量比增加,钢管的能量与变形、爆炸冲击能与粉末压实能单调增加.     

Using the Rasch model to validate stages of understanding the energy concept

In recent years, there have been efforts to bridge science education with developmental psychology to develop theories on students developing understanding of science concepts from elementary to high school and beyond. The present study intends to test one such theory on students developing understanding of the energy concept. The theory states that students develop understanding of the energy concept by going through the following qualitatively distinct stages: (a) energy as activity/work; (b) energy as sources/forms, (c) energy transfer, (d) energy degradation, and (e) energy conservation. Three classes, one each from 4th grade, 8th grade, and high school physics class (grades 10, 11, and 12), completed a performance assessment. Students' performances were scored based on three traits of energy understanding: attention capacity, qualitative relations, and quantitative relations; each of the traits was defined into five hierarchical levels consistent with the five stages of understanding the energy concept. The Many-Facet Rasch Measurement (MFRM) model was used to analyze the effects of rater scoring severity, students' stages of energy understanding (theta), and difficulties of energy understanding traits. Results show that there was a discontinuity among the stages of understanding the energy concept, supporting the theory on students developing the understanding of the energy concept.     

Using the bond energy density to predict the reinforcing ability of a composite

A model is proposed to predict the ability of a filler to reinforce a polymer. The model combines the effects of filler particle size, filler surface chemistry and filler volume fraction into one parameter called the bond energy density. Bond energy density is defined as the total interfacial bond energy per unit volume of a polymer composite. Bond energy density is determined by Fowkes's equation. The critical bond energy density, which is equivalent to the bond energy density of the composite when its tensile strength equals that of its matrix, determines whether a filler will reinforce or weaken a polymer. To get a filler reinforcing effect, the bond energy density of the composite must be greater than its critical bond energy density.     

On the measurement of the impact energy of ceramics at different loading rates in instrumented impact tests

Summary The impact energy of a ceramic is measured in instrumented impact tests by means of a novel high sensitivity striker tup. The measured impact energy shows a strongly increasing trend with increasing impact velocity. High speed cinematographic investigations indicate that a considerable part of the measured impact energy is transferred into kinetic energy of the moving specimen halves after impact. If this kinetic energy is subtracted from the measured values of the impact energy a quantity representing the true fracture energy is obtained which does not depend on the impact velocity.Published in Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 27, No. 6, pp. 23–27, November–December, 1991.     

汽车能量回收系统研究概述

在汽车节能化发展趋势下,能量回收系统研究受到广泛关注。汽车能量回收系统当前研究热点主要集中于再生制动能量回收、馈能悬架以及发动机废热能量回收三个方面。首先对这三类汽车能量回收系统的特点与发展现状进行详细回顾;然后指出各能量回收系统的优势与待解决的关键问题;最后提出相应解决方案并对新的能量回收利用途径进行有益的探索,为今后学者的研究提供借鉴。     

我国能源形势及发展对策

总结了近年来我国能源发展取得的成绩,研究分析了我国能源发展面临的形势和挑战,提出了当前和今后一个时期能源工作的主要任务。特别强调保证能源安全供应是能源战线的一项首要任务、基本任务和长期任务,同时要大力节约能源,调整优化能源结构,加快能源科技自主创新,扩大能源国际合作,推动能源科学发展,为经济社会健康、持续、协调发展提供保障。     

On the energy characteristics of ball lightning

A compilation of 17 observations of ball lightning showing the most energetic effects is presented along with estimates of their energy content. These observations were chosen from several thousand for the much stronger interaction of each ball lightning on its surroundings, and the method of energy estimation outlined. The case is put that some of the observations show a higher energy than self-contained chemical energy could provide. Comments have been added to the paper, arguing that the energy estimations themselves should be consistent with whatever model is used for ball lightning. For example, the presence of reacting nanoparticles releasing chemical energy may bring about the same observed effects with lower estimated energy.     

对我国中长期（2030、2050）节能发展战略的系统分析

首先,从全生命周期视角出发,对我国能耗增长的根源进行了剖析;其次,剖析了节能的基本概念和内涵,指出应重点区别建设型能耗和运行型能耗;最后,总结了中长期节能的战略目标,以及制度节能、系统节能、技术节能3类实现措施,并对系统节能开展了住宅寿命问题的案例分析。