谁能用最最简单的话解释下面的摄影原理
说白了，大晴天，把ISO设置成100，光圈设置成16，快门设置成1/125s，在此情况下您随便照都算正确曝光。以此为基础，如果光线变暗（阴天）就把ISO提高或者把光圈开大，或者快门减慢，在光线更强的情况下，就把ISO降低、或者快门减小、或者快门加快。这个法则还可以配合超焦距对焦法进行抓拍和盲拍：
h ttp://xjada.blog.sohu.com/32559057.html
气缸的sensor和接近开关的功能区别
气缸的sensor和接近开关的功能区别
汽缸开关属于磁性开关，需要磁铁才能响应，其他接近开关，电感式接近开关对金属物体有感应，电容式接近开关对液体，固体，粉末，塑料，玻璃等等都能感应包括金属.
磁性开关是开关内部是距离很近的两个舌片，其原理就是磁铁靠近，两个舌片被磁化，相互吸引而连在一起导通。不可以直接接220V,380V，因为其两舌片的距离极近，220V的电压足以击穿中间的空气形成通路
谁能帮忙找一小段（1000个左右单词）机械制造类的英语文章要带中文的翻译的。谢谢！
说个关于仿行车床和自动车床的文章吧.那是我帮一个朋友翻译之后的结果:
Trace lathes are machine tools with attachments that are capable of turning parts with various contours. also called duplicating lathes or contouring lathes, the cutting tool follows a path that duplicates the contour of the template, similar to a pencil following the shape of a plastic template used in engineering drawing. a tracer finger follows the template and, through a hydraulic or electrical system, guides the cutting tool along the workpiece without operator intervention. operations performed on a tracer lathe have been largely replaced by numerical-control lathes and turning centers (section 24.2)
lathes have been increasingly automated over the years . manual machine controls have been replaced by various mechanisms that enable cutting operations to follow a certain prescribed sequence . in a fully automatic machine ,parts are fed and removed automatically ,whereas in semiautomatic machines, these functions are performed by the operator
Automatic lathes, which may have a horizontal or vertical spindle and do not have tailstocks, are also called chucking machines, or chuckers . they are used for machining individual pieces of regular or irregular shapes, and are available in either single or multiple spindle types. in another type of automatic lathe, the bar stock is fed periodically into the lathe and a part is machined and cut off at the bar. automatic lathes are suitable for medium to high-volume production
仿行车床是一种加工机床,和附加配件一起,能够加工各种轮廓的旋转体. 也可以称为复制车床或者轮廓车床(在国内只叫仿行车床,我只是按字面把这一句翻译出来). 切削刀具跟随着复制模板的外形轮廓移动.类似于用铅笔沿着塑胶模板(曲线模板)的轮廓描绘工程图.仿行指针跟随模板,并且通过液压或者电气系统,不需要操作员干涉的情况下引导切削刀具沿着工件加工.目前仿行车床已经基本被数控车床和车削中心代替.(第24.2)
多年以来,车床已经逐步自动化了.手动控制的机床已经被各种能够按照指定次序执行加工的机制取代.一部全自动的机床,产品可以全自动地被送进和装卸;然而对于半自动机床,某些功能需要人手执行.
自动车床有水平主轴或者立式主轴,但是没有后机座的可以称作卡盘式车床. 他们用于加工个别形状规则或者不规则的产品.而且拥有单一或者多个主轴的类型; 另外一种自动车床,带有自动送料的系统,把条状原料定时地送进车床加工,加工完了之后从条料中切落. 自动车床适合中到高产量的生产.
自动车床有水平主轴或者立式主轴,但是没有后机座的可以称作卡盘式车床. 他们用于加工个别形状规则或者不规则的产品.而且拥有单一或者多个主轴的类型; 另外一种自动车床,带有自动送料的系统,把条状原料定时地送进车床加工,加工完了之后从条料中切落. 自动车床适合中到高产量的生产.
