城镇增长下的收缩：以武汉为例

首先从人口、经济、用地3个维度综合考察武汉市增长与收缩的全貌,并采用县区及街道2个尺度的数据定量描述了武汉市增长与收缩的特征与空间格局,发现武汉市下辖青山区、硚口区、汉阳区和蔡甸区存在局部较严重的收缩现象,空间上形成集聚,形态上呈“穿孔式”。进一步以青山区为案例,着重从资本视角探讨发生局部收缩的内在机制,发现其存在老龄化、少子化趋势,但局部收缩的主因是资本从产业部门的“逃逸”。     

An appearance‐preserving simplification method for complex 3D building models

The simplification of 3D building models to effectively reduce model complexity and improve rendering efficiency is an important component of 3D GIS. To reduce the data volume while preserving the model appearance, this article proposes a novel simplification method for complex 3D building models. Texture discontinuities are addressed by developing a new data model that records the mapping relation between the texture coordinates of each vertex and its neighboring triangles. The surface mesh of the building model is then segmented into regions, guided by topology and appearance. Finally, the mesh segmentation information is used to derive an improved error metric that considers both geometric and texture errors, and the texture coordinates are adjusted after each simplification operation. A series of comparative experiments alongside traditional methods demonstrates that our approach achieves a good balance between geometric fidelity and texture preservation, and produces simplified 3D building models with better visual quality.     

扬子陆块西缘寒武系砂岩的物源分析：对古地理位置重建和构造背景的指示

扬子陆块西缘寒武系主要为一套碎屑岩- 碳酸盐岩的岩石组合,前人研究多认为形成于相对稳定的克拉通盆地。但同时期出现的大陆岩浆作用显然与前期认定的克拉通盆地性质不符,需要借助扬子西缘的物质来源探讨构造背景。基于野外露头等资料,本文通过对扬子陆块西缘会泽和会东附近寒武系3件砂岩样品进行重矿物分析、电气石电子探针和碎屑锆石U- Pb测年分析,确定扬子西缘寒武纪沉积物的源区;并结合沉积序列等综合探讨扬子陆块西缘寒武纪的构造背景。沉积序列表明,扬子西缘寒武系沧浪铺组、西王庙组和二道水组主要由砂岩和白云岩等组成,沉积环境为滨岸—潮坪。细—粗砂岩碎屑颗粒为次棱角状—次圆状,分选较差;碎屑组分主要为石英,岩屑几乎全部为燧石,长石含量较少。测试分析结果表明：重矿物分析指示扬子西缘寒武系砂岩重矿物主要由锆石、赤—褐铁矿、电气石、钛铁矿、金红石、磷灰石等组成,重矿物组合指示岩浆岩为其主要母岩;电气石电子探针分析结果表明,物源主要来自于贫锂花岗岩和变砂岩、变泥岩;碎屑锆石测年分析表明物源区母岩主要为983~540 Ma岩浆岩。碎屑锆石年龄对比等综合分析表明,寒武系沉积物部分源自康滇古陆983~708 Ma的岩浆岩和变沉积岩,部分源自冈瓦纳大陆东非造山带663~540 Ma的岩石,物源区岩石经历再旋回产物作用。扬子西缘寒武系的沉积序列、碎屑锆石年龄谱图和碎屑组成等特征综合分析表明,扬子陆块西缘寒武系形成于前陆盆地。     

1：100万图号中行号、列号正误的快速判断方法

针对多个县(市)、区土地调查文字材料将1:100万图号中的行、列号用错而产生严重缺陷的事实,本人认真学习了"国家基本比例尺地形图分幅和编号"的基础知识,并总结归纳出简易的快速判断正误的方法,以杜绝类似差错的发生.     

Denitrification in Qi'ao Island coastal zone, the Zhujiang Estuary in China

Samples of sediments and the overlying water were collected in the Qi'ao Island coastal zone, the Zhujiang (Pearl River) Estuary (ZE). Denitrification rates, sediment oxygen demand (SOD) , and fluxes of inorganic nitrogen compounds were investigated with N2 flux method, using a self-designed continuous flow through and auto-sampling system. The results indicate that the denitrification rates varied between 222 and 908 μmol/(m2·h) with an average of 499 μmol/(m2·h). During incubation, the sediments absorbed dissolved oxygen in the overlying water with SOD ranging from 300 to 2 363 μmol/(m2·h). The denitrification rates were highly correlated with the SOD (r2 =0.77) regardless of the NO3- + NO2- concentrations in the overlying water, organ- ic carbon contents in sediments and water temperature, suggesting that the SOD was probably the main environ-mental factor controlling the denitrification in the Qi'ao Island coastal zone. There was a net flux of NO3- + NO2-into the sediments from the overlying water. The NH4+ flux from sediments into water as the result of mineraliza-tion was between 12. 3 and 210. 3 μmol/(m2·h) ,which seems limited by both organic carbon content in sedi-ment and dissolved oxygen concentration in the overlying water.     

Landscape Effects of Land Consolidation Projects in Central China——A Case Study of Tianmen City,Hubei Province

The goal of land consolidation in China is still to develop agricultural production. The study of landscape effects of land consolidation projects （LCPs） faces many difficulties because of the lack of government＇s interest and data. This paper, taking Tianmen City of Hubei Province in Central China as an example, presents a methodology for analyzing landscape effects of LCPs by GIS and Fragstats3.3. It describes landscape effects with indexes of Patch Density （PD）, Largest Patch Index （LPI）, Landscape Shape Index （LSI）, Interspersion and Juxtaposition Index （IJI）, Aggregation Index （AI）, and Shannon＇s Diversity Index （SHDI）, showing more regular shape, simpler structure and less habitat diversity after LCPs. It computes ten landscape indexes of four categories of patches including Cultivated Land, Road, Water Channel, and River and Pond. The indexes show that 1） cultivated land becomes more fragmental in patch area, less irregular in patch shape and more concentrated in block; 2） the transport capacity of roads and irrigation and drainage capacity of water channels have been improved; 3） the landscape change of river and pond can be summarized as decreasing scale, more regular shape, reducing connectivity and diversity of the class. LCPs can facilitate agricultural production as well as protect cultivated land and food security. However, it is doubted that the increase of cultivated land from LCPs results from the reducing in landscape diversity of water area.     

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基于特定序列的长牡蛎视黄酸反应元件预测

视黄酸受体和核受体超家族中的大部分成员对细胞整个分化、增殖过程都具有调控功能。视黄酸受体结合配体后激活,通过结合靶基因启动子区特定的核苷酸序列调控靶基因表达。视黄酸受体结合序列是由核心序列[A/G]G[T/G]TCA间隔不同碱基构成的重复序列,称为视黄酸反应元件。为了实现对长牡蛎基因组中含有的视黄酸反应元件的快速筛选预测,本研究利用Perl工具编写了一个可以批量筛选视黄酸反应元件的脚本,并对长牡蛎基因组中启动子区域序列进行筛选预测,共筛选到412个启动子区含有视黄酸反应元件的基因。随后,将这些基因在各种数据库中比对分析,预测其参与的生物学过程及可能的生物学功能。结果显示,大部分基因与蛋白质结合、核苷酸结合、水解酶活性、蛋白激酶活性等功能有关。     

长江口外高盐水入侵分析

本文根据１９７５～１９８２，１９８７～１９９０年东海海洋调查、１９８２～１９８３年上海市海岸带海洋水文调查和１９８８～１９８９年长江口河口锋调查资料，分析了高盐水入侵长江口外的特征和规律，结果表明，高盐水入侵边界的多年平均位置与长江水下三角洲的东边界大致一致，入侵长江口外的高盐水主要源于台湾暖水，冬季尚有黄海混合水入侵的迹象。文中还探讨了高盐水的入侵机理，并阐述了高盐水入侵对入海泥沙输移和长江水下三角洲的发育起着控制作用。