Relationship analysis between September precipitation in western China and 700 hPa wind field in East Asia

The regional wind index influencing September precipitation in western China has been defined using the 700 hPa u and v components of NCAR/NCEP reanalysis data of 1961 to 2006. There are three regional wind field indices: southwest, southeast, and north, and these indices reflect the change of East Asian monsoon. The relationship between the indices was studied, and results show that they not only have a close relationship, but also have independence. Moreover, there is an obvious relationship between the wind indices and the autumn in particular the September precipitation in western China. The effect of wind indices on rain occurrence is most different: the influenced area of the southwest wind index is larger than that of the southeast wind index, and the southwest wind index is a controlling factor on autumn precipitation in western China. The weakening of southwest wind is the main cause resulting in reduction of autumn precipitation on the east side of the Tibetan Plateau.     

Spatial-temporal pattern and population driving force of land use change in Liupan Mountains region, southern Ningxia, China

The Liupan Mountains is located in the southern Ningxia Hui Autonomous Region of China, which forms an important dividing line between landforms and bio-geographic regions. The populated part of the Liupan Mountains region has suffered tremendous ecological damages over time due to population pressure, excessive demand and inappropriate use of agricultural land resources. In this paper, datasets of land use between 1990 and 2000 were obtained from Landsat TM imagery, and then spatial models were used to characterize landscape conditions. Also, the relationship between the population density and land use/cover change （LUCC） was analyzed. Results indicate that cropland, forestland, and urban areas have increased by 44,186ha, 9001ha and 1550ha, respectively while the grassland area has appreciably decreased by 54,025ha in the study period. The decrease in grassland was most notable. Of the grassland lost, 49.4% was converted into cropland. The largest annual land conversion rate in the study area was less than 2%. These changes are attributed to industrial and agricultural development and population growth. To improve the eco-economic conditions in the study region, population control, urbanization and development of an ecological friendly agriculture were suggested.     

GIS在城市规划编制中的2个应用--原理、方法和实例

地理信息系统的应用领域日趋广泛和深入。本文讨论了GIS在城市规划编制工作中的2个应用,即街区建筑技术经济指标的统计分析和城市适宜建设用地数量和空间分布的分析。街区建筑技术经济指标的统计分析能够为确定街区改造方式、改造次序等提供可靠的、数量化的依据,城市适宜建设用地数量和空间分布的分析则可以为确定城市合理的发展规模和城市空间布局提供有力的依据。     

Composition of fish communities in an intertidal salt marsh creek in the Changjiang River estuary,China

Fish communities in a (third-order) intertidal creek in Dongtan marsh in the Changjiang (Yangtze) River estuary were investigated seasonally for one year. A total of 1 996 fish specimens (10 967.8 g) comprising 26 species and 15 families were collected. Abundances of fish communities in the intertidal salt marsh creek were primarily dominated by Boleophthalmus pectinirostris (19.8%), Collichthys lucidus (18.6%), Periophthalmus magnuspinnatus (18.2%), Liza haematocheilus (17.9%), and secondarily by Mugilogobius abei (8.5%), L. carinatus (7.2%), Odontamblyopus lacepedii (4.3%), and Acanthogobius ommaturus (3.9%); another 18 species were present only occasionally. Non-MDS ordination and SIMPER analysis indicated that there were two fish communities in the intertidal salt marsh creek. In spring, the communities were dominated by B. pectinirostris, P. magnuspinnatus, C. lucidus and M. abei; in summer, autumn, and winter by L. haematocheilus, L. carinatus, A. ommaturus and O. lacepedii. Some species showed strong habitat selection; L. carinatus and P. magnuspinnatus were distributed mainly in the upper and middle creek, while B. pectinirostris, M. abei and O. lacepedii inhabited the middle and lower creek. The study indicated that the salt marshes of the Changjiang River estuary are an important nursery and feeding habitat for many fishes and should be protected.     

中国泥盆纪聚煤作用的演化

泥盆纪是中国聚炮期之一，它标志着晚古生代聚炮作用开始，并不断发展。到石炭二叠纪达到高峰，导致中国重要聚煤期的出现。华南泥盆纪沉积十分发育，其聚煤作用受地壳运动和海水进退的控制，显示了从西南到东北规律的迁移。泥盆纪煤层是浜海或浅海环境的产物，某些煤含有多量的角质层物质，故称为角质残植煤，这与沉积环境及原始成煤质料有密切关系。     

基于三维扫描与打印的岩体自然结构面试样制作方法与剪切试验验证

无法大量制作表面形态完全一致的含自然结构面的剪切试样一直是困扰岩石结构面力学试验深入研究的难题之一。借助最新发展的3D打印和表面快速扫描技术,提出了岩石自然结构面试样制作新方法。该方法采用三维扫描仪获得岩石自然结构面表面形态的高精度点云数据,然后通过逆向工程软件重构自然结构面的表面形态和含自然结构面的虚拟剪切模型,进而通过3D打印技术制作含自然结构面的PLA（绿色环保材料聚乳酸）塑材模具,最后借助PLA结构面模具在制样盒内通过相似材料浇筑成型出剪切试样,从而实现批量制作结构面形貌完全一致的相似材料结构面剪切试样,满足多种组合试样方案下岩石自然结构面的深入分析。采用这一方法针对3种岩石自然结构面进行了批量制作和剪切试验测试表明：（1）浇筑制作成试样的结构面表面高程与原始结构面高程之间的误差分析显示,岩石自然结构面可以高精度地复制到剪切试样中;（2）相同剪切试验条件下多个剪切试样的剪切位移-剪切力曲线的重合度非常高,表明制作的结构面剪切样的一致性好且试验结果离散性小;（3）通过剪切结构面试样在剪切前后的表面形态扫描分析发现,相同试验条件下自然结构面的剪切破坏形态具有非均匀性。     

深圳海域麻痹性贝类毒素含量特征

根据 1996～ 1997年间深圳海域 (大亚湾和大鹏湾 ) 13种贝类 (华贵栉孔扇贝、马氏珍珠贝、翡翠贻贝、波纹巴非蛤、毛蚶、栉江瑶、联珠蚶、文蛤、棕带仙女蛤、僧帽牡蛎、菲律宾蛤仔、习见蛙螺和近江牡蛎 )体中的麻痹性毒素的检测数据 ,阐述了贝类麻痹性毒素的含量水平、年际变化、PSP中毒事件以及与其它海区贝类 PSP的比较     

青海工业发展模式选择

工业化是一个国家和地区经济发展的核心、结构转变的动力。加快推进新型工业化是我国新世纪提出的宏伟战略,也是青海实现社会经济快速、稳定、健康发展的重要内容。文章在考察并总结建国以来青海工业发展历史进程及其阶段性特点的基础上,提出"点轴渐进—东西两翼"工业发展模式作为青海工业可持续发展的现实选择,为青海在经济全球化、中国入世和西部大开发背景下实现经济起飞提供理论依据和政策参考。     

被动型原子频率标准体系内优势组合的研究

提出了被动型原子频率标准体系内优势组合的建议.扼要地介绍了以汽泡型铷原子频率标准为背景的体系内优势组合的研究情况及其初步结果.