对我国数字城镇建设的几点思考

我国城镇化快速发展迫切需要在全国大中小城市和小城镇加快实施信息化战略,建设具有中国特色的“数字城镇”。本文从“数字城镇”技术构成出发,分析了我国“数字城镇”发展现状及其面临的主要科技问题,提出要加强对“数字城镇”数据平台、综合信息服务平台、业务应用平台构建等关键技术问题的研究,以从整体上提升我国城镇信息化的水平。     

Seawater flux through Taiwan strait

After the winter and summer current structures on two or three latitudinal sections in Taiwan Strait were obtained from the measured current data, the seawater fluxs through the sections were calculated. In summer, the currents in the central and northern part of Taiwan Strait normally flow northward at a net flux of 3.32×10⁶m³/s. In winter, the high temperature and salinity Kuroshio and South China Sea water enter Taiwan Strait from the southem section at 1.69×10⁶m³/s and 0.59×10⁶ m³/s respectively, while the East China Sea water enters Taiwan Strait from the northern section at 1.02×10⁶m³/s. About 0.40×10⁶ m³/s of the seawater enters the South China Sea along the coast of Fujian and Guangdong; the other 0.62×10⁶ m³/s of the seawater is mixed with the Kuroshio water and the South China Sea water in the northern sea areas. The net northward flux is 1.74×10⁶m³/s in winter.     

四川盆地大气边界层气象资料数据系统

本文介绍在IBM-PC微机(或兼容机)上利用DBASEⅡ、BASIC和FOR-TRAN语言设计和研制的一套大气边界层气象资料数据库软件系统,给出它的主要结构和功能。该系统实现了大气边界层气象资料共享和信息化处理,不但操作简便、快速、准确、稳定性好,而且具有较强的通用性和较大的实用价值。     

Regional Differences of China′s Urban Expansion from Late 20th to Early 21st Century Based on Remote Sensing Information

This study investigated the regional differences of China′s urban land expansion from the late 1980s to the year of 2008, based on the spatio-temporal analysis of CLCD (China′s land cover/land use database) datasets which were mainly produced from remote sensing imagery data. A newly defined urbanization level index (UI), based on urban land area, is proposed to describe Chinese urban expansion process at 1 kilometer, provincial, regional, and na-tional scales, together with the absolute urban expansion index (UEa) and the relative urbanization expansion index (UEr). The results indicate that the percentages of total land area occupied by urban in the late 1980s, 1995, 2000, 2005, and 2008 were approximately 0.25%, 0.32%, 0.33%, 0.43% and 0.52% of China′s total land area, respectively. Between the late 1980s and 2008, the total urban expansion in the mainland of China was 2.645 × 104 km2, resulting in an annual urban expansion area of about 1322.7 km2/yr, with the UEr of 111.9%. This study also finds that there has been an obvious spatial gradient of urbanization ratio running from the east coast to the west inland, and the urbanization gaps among different regions have persisted over the past two decades. The study also reveals obvious temporal varia-tions of the urbanization rates. There was very little urban growth during the period of 1995-2000 due to the governmental policy factors.     

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Rotary spectrum analysis of tidal current in the southern Yellow Sea

A complete set of one-month Acoustic Doppler Profiler (ADP) current data at a station in the southern Yellow Sea (SYS) is analyzed using the rotary spectrum method. The results revealed different rotary properties between barotropic and baroclinic tidal currents. The barotropic and baroclinic tidal currents rotate elliptically counter-clockwise and clockwise, respectively. Meanwhile, baroclinic bottom tidal currents are almost along-isobath. The baroclinic cross-isobath velocities attenuate quickly at the bottom, implying important effects of bottom topography on the cross-isobath motions.     

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贺兰山群变质杂岩中的变余动力变质岩

贺兰山群变质杂岩形成于晚太古代,遭受过多期变质和变形的改造,其中发育了不同期次和层次的动力变质岩。变余韧性剪切带内发育了条带状片麻岩和变粒岩,相伴有变余鞘褶皱和构造透镜体,变余韧性剪切带的变形发生在较低的温度、压力条件下,地壳加厚作用的初期。变余糜棱岩貌似条带状片麻岩,但在青石中保留了早期石英拔丝构造和加粗的动态重结晶长石集合体。糜棱岩化作用的温度在550℃以上,变形后沿面理形成了饼状或椭圆状青石,变晶时温度近600℃,压力近300MPa。     

东秦岭石界河群中石榴石成分环带所记录的PTt轨迹

位于河南省西峡县北部地区的石界河群榴云片岩中的石榴石发育有很好的结构和成分环带。本文应用微分热力学方法对其环带成分进行计算,确定出一条顺时针方向的PTt轨迹。该轨迹与应用矿物共生组合世代关系确定的PTt轨迹十分吻合。     

SEA LEVEL RISE OF THE ZHUJIANG RIVER DELTA AND NEOTECTONICS

A linear regression analysis of 28 selected tide-gauge stations of the Zhujiang Estuary shows that there has been a tendency of local sea level rise at a rate of 2.028 mm per year. The origin of the variation is significantly attributed to the local tectonic movement of discrepant fault-block. Based on this, four types of relative local sea level changes are classified. According to calculation, half of the fertile land, or 800 km2 of the delta plain will have been submerged by sea water by about 2040. This will yield a significant influence on the economic construction and human activities.