白平衡，你会用吗？

也许你玩数码相机有一段时间了，也许你知道自己的数码相机有白平衡设置，也许你根本就没有去理会它……     

天使爱美丽——人物照片处理技巧大荟萃

数码相机越来越普及,身边的朋友们一个个都开始加入到数码影像的队伍中。不用数码相机的时候朋友们也许并不热衷拍照，数码相机让我们发挥最大的拍摄热情。照片一堆堆的拍出来了，但是往往会发现没有几张是自己满意的，     

泡泡与童年

在公园里散心，偶然发现有小朋友在吹泡泡，看着那美丽的泡泡在阳光下飘啊飘的，不禁来了兴趣，掏出随身携带的数码相机就开始泡泡和儿童的拍摄。     

数码暗房——让你的风景照片更出色

五一是大家出游的好日子，朋友们是不是都已经跃跃欲试想好了出游的计划?准备好了自己的数码相机去拍照呢?呵呵，这次给大家讲讲风景照片的后期处理。希望能对你们有所启发。让自己的照片更出色，让我们从Photoshop做起。下面我就用几个例子来说明风景照片的一些初级调整。     

让数码相机也做个多面手

自从有了数码相机之后，在进行各种郊游拍摄之后，我们便开始不满足于把它当作一般的拍摄工具，想更深地挖掘数码相机的使用技巧。本就给大家讲讲对数码相机的另类使用方式。     

Long‐term trends in biological indicators and water quality in rivers and streams of New York State (1972–2012)

Government‐operated water quality monitoring programmes and their long‐term datasets are crucial to documenting improvements in water resource condition in response to changes in pollutant regulation. We present trends in the biological assessment of water quality (benthic macroinvertebrates) and water chemistry, to determine how these indicators of water quality have responded to shifts in pollutants and regulation in streams and rivers of NY between 1972 and 2012. Change in the results of NYS's multimetric index of biological integrity, the Biological Assessment Profile (BAP) score, was compared between four, 10‐year periods at 30 large river and 138 wadeable stream sites. Water Chemistry trends were analysed through calculation of Weighted Regression on Time, Discharge, and Season from 11 long‐term, large river locations from across NYS. Overall, results suggest small, incremental improvements in biological indicators and a shift from point source dominated pollution to nonpoint sources. From 1972 to 2012, 33% of large river sites sampled improved and 13% declined in biological assessment of water quality, 58% of wadeable stream sites sampled showed no change. Macroinvertebrate community models suggest that impact sources are now dominated by nonpoint nutrient sources. Trends in water chemistry concentrations suggest that ammonia, chloride, total Kjeldahl nitrogen, and total phosphorus had the strongest correlations with time. Total phosphorus and total Kjeldahl nitrogen decreased at base flow and increased during high flows, whereas ammonia decreased across a range of discharges, indicating the shift to nonpoint sources of nutrients and supporting the trends observed in biological indicators.     

The generation and properties of boundary films formed by diesel fuel at a steel/steel conjunction

Thin gel-like films are seen on the lubricated surfaces within diesel fuel injection equipment. The formation and properties of these films are investigated, under sliding conditions, using disc-on-plane machines; one steel has been used throughout. The development and maintenance of separation is measured by voltage drop and, during running-in to a high conjunction resistance, films are produced which are similar to those seen in practice. It is shown by static tests that separation is maintained by these films, which behave as quasi-elastic solids. The films are not miscible with diesel fuel and are not produced when the fuel is in static contact with the steel. They exhibit similar electrical properties under static and dynamic conditions: this was unexpected and is not yet understood. It is postulated that the films are produced by chemical reactions, and that the surface polishing observed is due to the same reactions