无反相机的文艺复兴

从开始的科技路线到现在的复古风潮,几年时间里无反相机由外到内都发生了巨变。我们为你集结了市面上最常见的几款无反相机．来看看他们孰优孰劣。     

离机控制快门

想在低光环境下拍摄时减少机震,或避免在野外拍摄时惊动被摄对象,这里我们将告诉你四种方式,让你无需接触相机也能拍照。即便是按快门也会让相机产生抖动,这是众所周知的,所以我们将告诉你几种方法,让你在无须触碰相机的情况下触发快门。如果你仅仅是想通过不触碰相机来减少机震的话,那么你可以使用相机的延时自拍功能。许多相机都可以     

进相机运行故障成因及处理

进相机运行故障成因及处理刘炳南安徽省芜湖县水泥厂（２４１１２２）进相机在运行一段时间后，产生较大的环形火花，换向器表面发黑甚至烧灼成凹坑，继续使用会造成恶性循环，导致进相机损坏同时也危及到主绕线式电动机的安全运行。以ＦＺ－２型进相机为例，换向器表面火...     

进相机在大型异步电动机上的应用

为提高供电线路的功率因数,一般是在电网末端安装使用同步电动机和增加无功补偿设备来实现。异步电动机人工补偿一般采用移相电力电容器、绕线异步电动机同步化和进相机等方法。本文对大型异步电动机采用进相机补偿作一介绍。一、进相机工作原理进相机改善功率因数的原理基于在绕线型异步电动机转子电路内加入附加电势Ek,当E_k和转子电路内主电势E_2成90°角时,将影响功     

如何使用B门

<正>Mark Hamblin教给你如何利用B门控制相机的曝光时长当你用相机上的自动测光模式时,比如光圈优先模式,相机提供的最长快门时间就是30秒。在绝大多数的光线条件下这么长的曝光时间都是绰绰有余的——但某些时候你甚至需要比这还要长很多的曝光时间。这时B门便派上用场了。只要你一直按着快门,B门就可以使相机一直进行曝光,这样一来你就可以进行长达几分钟甚至长达几小时的曝光了。使用B门拍摄的典型题材包     

4款旁轴数码相机

旁轴取景式照相机(以下简称旁轴相机)顾名思义,就是取景与摄影光路入射路径不在同一条轴线上的照相机,其取景装置独立成系统.传统相机中有许多就是旁轴相机,现在已经有多数数码相机承袭了这一技术.     

《新奥尔良电车》

<正>相机介绍现今八十多岁的弗兰克也记不得这张照片当年用的是哪款莱卡相机拍摄的了,不过,他对莱卡ⅢC却一直情有独钟。20世纪20至50年代,德国一直雄踞世界照相机王国的宝座。莱卡相机也是当时世界各国竞相仿制生产的名牌相机,在世界上享有极高的声誉。在二十世纪五十年代到六十年代期间,莱卡相机已经相继研制出了2型、3型相机。与此同时开始转换研制G系列的1G、2G、3G相机。到目前为止,莱卡M系列仍在出新产品。在第二次世界大战中,莱卡相机成了当时随军记者的重要工具。照片背后《美国人》在法国首次出版于1958年,然后是1959年在美国。弗兰克的惊世名著《美国人》刚出版时,此书遭到了他人的质疑。直到十多年后,这本书才引起了人们的关注,不仅是在美国,全世界的摄影家都在从中汲取养分,从而开     

为尼康F-801S相机做快门线

在杂志上常看到影友为佳能EOS相机用小插头自制电子快门线的文章,但未曾见过为尼康相机做快门线的介绍.心想能不能为自己的尼康F-801S相机做一条快门线?我给侯紫老师发了封电子邮件,把想法给他说了说,很快就收到回复,侯紫老师说也曾用过F-801S相机,曾经用尼康手柄改制成一根快门线,不愧为机电工程师,还把图也画好一并传了过来.好是好,我到哪去找一个手柄呢?     

数码单反一日通

掌握相机的使用,并不是什么难事。我们将向你介绍一些简单的技巧,掌握了这些,你就能在一天的不同时间里拍出好照片。忙碌的生活节奏是否让你苦于没有时间熟练掌握心爱的相机？为了解决这个问题,将你培养成更加优秀的摄影师,我们特别策划了本期专题。     

致热爱胶片摄影的你

<正>对于大多数人来说,胶片相机算是情怀的一种象征。风靡上世纪的经典胶片相机早已成为一代人的记忆,与数码相机比起来,需要冲洗的胶片既费时间又费钱,但其实在性能上很多胶片相机也不输数码相机。在这里我们推荐了几款发烧友心中不可复刻的胶片相机。难以复制的经典——康泰时G21996年日本Kvocera公司推出的可更换镜头的旁轴取景AF照相机——康泰时G2曾被评为最值得收藏的胶片相机之一。坚固的钛机身之内包含了自动对     

Aluminum,Arsenic, Beryllium,Cadmium, Chromium,Cobalt, Copper,Iron, Lead,Mercury, Molybdenum,Nickel, Platinum,Thallium, Titanium,Vanadium, and Zinc: Molecular Aspects in Experimental Liver Injury

Experimental liver injury with hepatocelluar necrosis and abnormal liver tests is caused by exposure to heavy metals (HMs) like aluminum, arsenic, beryllium, cadmium, chromium, cobalt, copper, iron, lead, mercury, molybdenum, nickel, platinum, thallium, titanium, vanadium, and zinc. As pollutants, HMs disturb the ecosystem, and as these substances are toxic, they may affect the health of humans and animals. HMs are not biodegradable and may be deposited preferentially in the liver. The use of animal models can help identify molecular and mechanistic steps leading to the injury. HMs commonly initiate hepatocellular overproduction of ROS (reactive oxygen species) due to oxidative stress, resulting in covalent binding of radicals to macromolecular proteins or lipids existing in membranes of subcellular organelles. Liver injury is facilitated by iron via the Fenton reaction, providing ROS, and is triggered if protective antioxidant systems are exhausted. Ferroptosis syn pyroptosis was recently introduced as mechanistic concept in explanations of nickel (Ni) liver injury. NiCl₂ causes increased iron deposition in the liver, upregulation of cyclooxygenase 2 (COX-2) protein and mRNA expression levels, downregulation of glutathione eroxidase 4 (GPX4), ferritin heavy chain 1 (FTH1), nuclear receptor coactivator 4 (NCOA4) protein, and mRNA expression levels. Nickel may cause hepatic injury through mitochondrial damage and ferroptosis, defined as mechanism of iron-dependent cell death, similar to glutamate-induced excitotoxicity but likely distinct from apoptosis, necrosis, and autophagy. Under discussion were additional mechanistic concepts of hepatocellular uptake and biliary excretion of mercury in exposed animals. For instance, the organic anion transporter 3 (Oat3) and the multidrug resistance-associated protein 2 (Mrp2) were involved in the hepatic handling of mercury. Mercury treatment modified the expression of Mrp2 and Oat3 as assessed by immunoblotting, partially explaining its impaired biliary excretion. Concomitantly, a decrease in Oat3 abundance in the hepatocyte plasma membranes was observed that limits the hepatic uptake of mercury ions. Most importantly and shown for the first time in liver injury caused by HMs, titanium changed the diversity of gut microbiota and modified their metabolic functions, leading to increased generation of lipopolysaccharides (LPS). As endotoxins, LPS may trigger and perpetuate the liver injury at the level of gut-liver. In sum, mechanistic and molecular steps of experimental liver injury due to HM administration are complex, with ROS as the key promotional compound. However, additional concepts such as iron used in the Fenton reaction, ferroptosis, modification of transporter systems, and endotoxins derived from diversity of intestinal bacteria at the gut-liver level merit further consideration.     

THERMOPLASTIC,FLEXIBLE, AND RECYCLABLE COMPOSITES,DESIGN, PREPARATION,AND CHARACTERIZATION

Glass fiber reinforced composites based on thermosets are the traditional materials used for many applications due to their good mechanical properties. The non-recyclability of these materials has led to the necessity to develop thermoplastic composites and industrial processes for their manufacture [1]. The present paper deals with the preparation of thermoplastic pre-pregs unidirectionally reinforced with Twarn® and their mechanical characterization.     

DUO-ICP-AES测定精对苯二甲酸中的钴、铬、铁、锰、钼、镍、钛

采用DUO-ICP-AES同时测定精对苯二甲酸中钴、铬、铁、锰、钼、镍、钛,并对仪器的分析线选择、背景校正、入射功率、雾化器压力、辅助气流量、冷却气流量、蠕动泵转速的影响及共存元素的干扰、硝酸铯灰化助剂等因素进行了详细的研究。方法的检测限:钴0.0097 mg/L;铬0.0021 mg/L;铁0.0078 mg/L;锰0.0012 mg/L;钼0.0027 mg/L;镍0.016 mg/L;钛0.0027 mg/L,回收率和精密度分别为93.0%～99.5%和0.37%～3.2%。该方法快速简便,具有良好的精密度和准确度,适用于进出口精对苯二甲酸的日常检验。