Information models used to manage engineering change: A review of the literature 2005-2010

Engineering change is a significant part of any product development programme. Changes can arise at many points throughout the product life-cycle, resulting in rework which can ripple through different stages of the design process. Managing change processes is thus a critical aspect of any design project, especially in complex design. Through a literature review, this paper shows the diversity of information models used by different change management methods proposed in the literature. A classification framework for organising these change management approaches is presented. The review shows an increase in the number of cross-domain models proposed to help manage changes.

葛洲坝截流24年来中华鲟产卵群体结构的变化

以1981～2004年间捕获的中华鲟(AcipensersinensisGray)亲鲟样本为研究材料,研究葛洲坝截流24年来中华鲟繁殖季节中坝下30km范围内产卵群体结构的变化情况。测定与统计结果显示,中华鲟雌雄性比由1981～1983年的1.10∶1降低到1987～1989年的0.63∶1,而后上升到2003～2004年的5.86∶1。雌鲟平均体长由1990～1992年的263.1cm增加到1999～2001年的276.7cm,升幅为5.2%(差异极显著);平均体重由1990～1992年的202.4kg

Population status, threats and conservation of the Yangtze finless porpoise

The Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis) is currently limited to the middle and lower reaches of the Yangtze River from Yichang to Shanghai, China, and the adjoining Poyang and Dongting Lakes. Its population size has decreased remarkably during the last several decades due to the heavy impact of human activities, including overfishing of prey species, water development projects that cause attendant habitat loss and degradation, water pollution, and accidental deaths caused by harmful fishing gear and collisions with motorized vessels. It was estimated that the number of remaining individuals was down to approximately 1800 in 2006, a number that is decreasing at a rate as high as 5% per year. Three conservation measures - in situ and ex situ conservation and captive breeding have been applied to the protection of this unique porpoise since the early 1990s. Seven natural and two "semi-natural" reserves have so far been established. Since 1996, a small group of finless porpoises has been successfully reared in a facility at the Institute of Hydrobiology of the Chinese Academy of Sciences; three babies were born in captivity on July 5, 2005, June 2, 2007 and July 5, 2008. These are the first freshwater cetaceans ever born in captivity in the world. Several groups of these porpoises caught in the main stream of the Yangtze River, or rescued, have been introduced into the Tian'e-Zhou Semi-natural Reserve since 1990. These efforts have proven that, not only can these animals survive in the area, they are also to reproduce naturally and successfully. More than 30 calves had been born in the reserve since then, with one to three born each year. Taking deaths and transfers into account, there were approximately 30 individuals living in the reserve as of the end of 2007. Among eight mature females captured in April 2008, five were confirmed pregnant. This effort represents the first successful attempt at off-site protection of a cetacean species in the world, and establishes a solid base for conservation of the Yangtze finless porpoise. A lesson must be drawn from the tragedy of Chinese River Dolphin (Lipotes vexillifer), which has already been declared likely extinct. Strong, effective and appropriate protective measures must be carried out quickly to prevent the Yangtze finless porpoise from becoming a second Chinese River Dolphin, and save the biodiversity of the Yangtze River as a whole.

Revision of the genus Niwaella in China (Pisces, Cobitidae), with description of two new species

Loaches of the genus Niwaella, family Cobitidae, are distributed only in East Asia. At present only in Japan and South Korea have fishes of the genus Niwaella been found. Herein we revise the genus Niwaella in China. Son and He ( 2001) transferred the species Cobitis laterimaculata to the genus Niwaella, but their specimens were not N. laterimaculata, but a new species, N. longibarba sp. n., collected from Cao'ejiang River, Huangzezhen, Chengxian County, Zhejiang Province. The new species is distinguished from N. laterimaculata by its colour pattern of a row of slightly large, and long, scattered dark brown vertical bars on the dorsolateral surface, two or three striations on the caudal fin, and long barbels and undeveloped mental lobes. In this paper we also describe another new species, N. xinjiangensis sp. n., collected from Xinjiang River, Guangfeng County, Jiangxi Province, May 1990, with diagnostic colour pattern of 17 - 20 large and long, dark brown vertical bars on the dorsolateral surface, a dark stripe or rounded black spots along the lateral midline and some blotches below the lateral midline; it is a large-sized species, with shorter barbels, and longer caudal peduncle. Thus five species of the genus Niwaella are known, three are endemic to eastern China and two are endemic to either Japan or South Korea.

黄土丘陵区小流域综合治理生态经济过程分析——以宁夏隆德县李太平小流域为例

从生态经济系统分析角度出发,对小流域生态经济结构及其演变进行分析,以期评价小流域生态经济效益。对比分析了小流域生态经济系统土地利用结构及其适宜性、产业结构、消耗结构和饲料生产平衡,利用线性模型对土地利用结构进行了优化模拟,采用描述生态系统稳定性的多样性指数描述流域经济系统稳定性,并用静态和动态模型对治理经济效果进行评价。流域农、林、牧用地比例由1990年的6．2:2．0:1．0变为2003年的1．9:1．4:1．0;农业产值所占比重由79．6％下降为54．8％;林业、牧业、副业产值比例分别由9．6％、9．6％、1．1％上升为22．7％、 15．1％、7．4％。收入多样性指数呈增加趋势,消耗结构趋向合理,饲料供需平衡,经济评价中各指标均显示经济效益显著,表明生态经济结构明显有利于生态经济系统的进展演变,流域生态经济结构趋于稳定,生态经济效益显著。

黄土丘陵区纸坊沟流域农业生态经济安全评价

以近70年纸坊沟流域农业生态经济系统演变过程为基础,利用国家"九五"科技攻关项目中所提出的评价指标体系,对纸坊沟流域不同发展阶段标志年份的农业生态经济安全状况进行了评价,得出:农业生态经济系统在1938、2000、2005年处于亚安全状态,1958、1975年处于极端不安全状态,1985、19901、995年处于不安全状态。通过对农业生态经济安全变化驱动力的分析,预测了纸坊沟流域农业生态经济安全的发展趋势,提出了黄土丘陵区实现农业生态经济安全的策略:以培育主导产业为中心,完善农业系统循环链网,调整产业结构,实现农业资源的有效、永续利用。

1960～2005年汕头500hPa高度变化

分析汕头气象站1960-2005年500hPa高度的气候变化特征，得出存在年际和年代

国家自然科学基金2005年半导体科学学科申请概况分析

2005年国家自然科学基金委员会半导体学科受理的面上项目申请数继续大幅度上升，本文简介2005年半导体学科基金申请与资助概况，分析半导体学科受理申请的近期动态，介绍学科拟采取的对策，并附2005年半导体学科批准资助的面上项目及重点项目，供广大科研人员参考．