构成

都市韵律 （作者：林吴养 广东广州） 拍摄参数：宾得＊ist DS相机．宾得SMC DA 10—17mm f／3．5—4．5ED（IF）变焦镜头（10mm端），ISO 400，平均测光，f／5．6．1／50秒。     

包围曝光

这个智能的功能可以让你得到最合适的曝光。在复杂的光线条件下,即使是最先进的测光系统也未必能够准确地曝光。尤其是在明暗区域交替出现的时候,相机的自动测光往往令人失望。有时候我们再也没有第二个机会拍摄,而且也没有时间去测光。在这种情况下,不要放弃,     

深入了解包围曝光

MarcusHawkins将详解包围曝光技巧,让画面细节得到最佳呈现。●包围曝光,就是用比正常曝光更募一些和更暗一些的曝光参数,分别拍摄多张照片的方式,是这样吗？是的。所谓包围曝光,就是对同一场景以不同的曝光参数拍摄一系列照片。之所以要使用包围曝光有两个原因,首先。它是一种保险措施,最大程度地保证你能获得曝光理想的照片（因为相机的测光系统并非万无一失）其次,你也可以利用包围曝光所得的照片进行后期合成。     

使用点测光

掌握点测光模式,保证精准的测光。在测光模式方面,你的相机提供了多个选择。其中包括了中央重点测光、平均测光、局部测光、多区测光以及点测光等,而点测光模式,让你能够针对所选择的拍摄对象上很小的局部区域进行精确、独立的测光。在光线不均匀的条件下——比如背景与主体之间的亮度差异     

快速入门，6步玩转数码单反相机

被测光难住了？对曝光感到困惑？阅读以下实用速成指南,拍摄更好的照片……这里,我们讲述了一些使用相机时可能会有疑惑的设置问题,集中于测光和曝光,两个我们被反复要求提供建议的方面。另外,我们也准备了一些分析照片的简便技巧。为了开始这场破解相机功能之旅,我们首先插入一些你必须知道的基本设置知识,以助于更好地利用它们。     

宾得K-7中端悍将

20世纪60年代，宾得曾在广告中喊出一句家喻户晓的口号：“Just holda Pentax”，意思是说只要拿起宾得相机，一切都尽在学握中。这句话如今完全可以拿出来用作K-7--该公司最新的旗舰数码单反相机——的宣传语。     

宾得K-7中端悍将

20世纪60年代，宾得曾在广告中喊出一句家喻户晓的口号：“Just holda Pentax”，意思是说只要拿起宾得相机，一切都尽在学握中。这句话如今完全可以拿出来用作K-7--该公司最新的旗舰数码单反相机——的宣传语。     

现代派影像构成

多幅照片的组合,能让我们体会到光阴的匆匆流逝。例如说我们使用相机的多重曝光功能针对同一场景拍摄两张不同的照片,镜头中来往的人群就会留下两个深浅不同的鬼影。当然我们也能以更富创意的方式,将不同照片切割拼合在一起,得到更加醒目的视觉效果。     

SHOOT！大师班 为你打造最完美的摄影技巧改进计划——掌握测光模式

在你拍摄不同的物体时,使用不同的测光模式可能会得到完全不同的效果。下面就跟随我们的文章来探索测光模式的奥秘吧！     

色彩

草原暮曲 拍摄参数：尼康D70,尼克尔AF 70-300mmf／4-5．6D（135mm端），ISO 400，点测光，f／6．7，1／1000秒。     

构好图,出好片

<正>这里有你需要的、关于摄影的一切建议。本期重点:1.转换黑白人像2.修改前景3.强化反差4.内部透视控制一张不错的照片和一张出色的照片有什么分别?什么元素能组成绝佳的构图?如果你需要一些建议为日常的拍摄注入情趣,我们的专家会给你提供满意的答案。他们正在这儿等着你!这里就是你获取照片点评和得到实用建议的地方。     

聚氨酯/纳米复合材料研究

用纳米SiO2,CaCo3，蒙脱土和材料复合聚氨酯，得出用蒙脱土作填充料时有最好的复合效果。并且在蒙脱土含量为1%时其力学性能最高，用差热分析和红外光谱对其原理进行了初步分析。     

Composition of oil

International trade in palm oil has increased considerably over the last ten years, and so too has the trade in processed palm oil products, especially palm fractions. It is important to establish reliable purity criteria for palm oil, not only because of the commercial need to verify oil authenticity, but also to comply with foodstuff labelling legislation in many countries. Palm kernel and coconut oils both contain about 47% lauric acid. This gives the oils close similarities in physical and chemical properties. The oils do differ, however, and it is important to be able to distinguish between them. Purity problems can arise as a result of commingling of oils with one another, or as a result of fractionation perhaps coupled with subsequent blending. A research program jointly funded by the (U.K.) Ministry of Agriculture, Fisheries and Foods, the Federation of Oils, Fats & Seeds Associations Ltd (FOSFA International), and the Leatherhead Food RA, was established to study purity characteristics of the major edible vegetable oils. Forty-seven samples of crude palm oil were obtained from reliable sources, often plantation managers, together with five samples of palm olein and eight samples of palm stearin. Fifty-four palm kernel and 23 coconut oils were obtained in the laboratory from seed samples of known geographical origins and authenticities. These oil samples were analyzed for fatty acid, triglyceride, sterol and tocopherol compositions; the melting properties were also determined, and in the case of palm oil the compositions of the acids at the triglyceride 2-positions were measured. Compositional ranges will be presented for the different geographical production areas in each case and related to existing data, e.g., of PORIM and Codex. An initial statistical analysis of the results has shown that a combination of values from the carbon number analysis differentiates palm kernel and coconut oils, and can be used to decide on the proportion of each in a blend. In the case of palm oil samples suspected to be contaminated with palm fractions, it was found useful to plot melting point against iodine value, and to compute the product of the C48 triglyceride content and the palmitic acid enrichment factor.     

醇解产物组成的计算

用同样的原料和配方合成醇酸树脂因醇解工艺不同会得到不同的结果。人们对醇解工艺和醇解产物的研究大都停留在实验数据阶段,没有为分析和设计醇酸树脂提供醇解产物的计算方法。为了配合采用高分子反应统计理论分析和设计醇酸树脂的配方和生产工艺,文中给出醇解产物组成的计算方法及适用范围。此方法计算所得结果虽然与实验数据有误差,但此误差导致醇酸树脂分析或设计的最终误差远小于试验或生产正常的质量波动,因而是可接受的。     

雪松松针挥发油成分分析

以无水乙醇、乙酸乙酯、石油醚为溶剂．采用分级萃取的方法分别从新鲜和干枯雪松松针中提取挥发油,利用气相色谱／质谱联用仪(GC-MS)对其化学成分进行分析鉴定。结果表明：新鲜松针中有65种组分,其主要成分是烷烃、烯酸、烯酮、甾醇类,而干枯松针的组分有44种,其主要成分是烷酸、酮类、酯类以及甾醇类物质,其中甾醇类物质的含量比较高。干枯松针中的组分存在形式相对比较稳定。     

硝卤成分的研究

<正> 盐卤的成分在文献中虽有很多介绍,但硝卤的成分却未见报导。本文对硝卤的成分作了研究,证明硝卤中除含无机盐外,还含有腐殖酸,腐殖酸的存在是硝卤和盐卤的主要区别。现将实验结果报导如下: 一、硝卤的来源农村中用取自地表约0～20mm的盐碱土,经年堆积,熬制硝酸钾后遗留的母液,俗称硝卤。本实验所     

Lipid Composition of Garlic

Neutral, glyco- and phospholipids of garlic were resolved into their component fractions by thin layer chromatography. Neutral lipids contained considerable quantities of monoglycerides (18.5%), diglycerides (14.2%), sterols (16.3%) and triglycerides (41.5%) respectively. The phospholipid fraction was rich in phosphatidyl choline (23.5%), phosphatidyl ethanolamine (17.9%), lysophosphatidyl choline (11.8%) and lysophosphatidyl ethanolamine (8.2%). Digalactosyl diglyceride (10.1%), sterol glycoside (15.6%), cerebrosides (8.1%), acylsterol glycoside (38.6%) and monogalactosyl diglyceride (22.5%) were the major components of the glycolipids of garlic. Lauric, myristic, palmitic and linoleic acids constituted the major fatty acids of monoglycerides, diglycerides and free fatty acid fractions whereas palmitic, linoleic and linolenic acids were the major fatty acids of triglycerides. Palmitic and linoleic acids were the major fatty acids of garlic phospholipids. Except the acylsterol glycoside fraction glycolipids were rich in lauric, palmitic, linoleic and linolenic acids; palmitic acid was the only major fatty acid of acylsterol glycosides.     

Composition of soybean lecithin

Commercial soybean lecithin is a complex mixture containing ca. 65–75% phospholipids together with triglycerides and smaller amounts of other substances. The major phospholipids include phosphatidylcholine, phosphatidylethanolamine and inositol-containing phosphatides. Other substances reported include carbohydrates, pigments, sterols and sterol glycosides. This paper reviews the nature of the compounds found in soybean lecithin and our present knowledge of its composition.