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111.
GPS���ܵ��㶨λ��Ӱ������ʱ������ؼ���ʩ���� 总被引:1,自引:0,他引:1
??GPS??????λ?????????У?????????????????估???????λ??????????????????????????????????????????λ????????????λ?????????????????????????????????????????????????????????伸?ι?????????????????????????????Щ??????????????????????????????????????????????????????? 相似文献
112.
1博兴县新农村建设中存在的问题(1)村庄建设闲置浪费土地严重。博兴县共有行政村448个,由于历史原因,大部分村布局松散,居住零乱,闲置浪费土地多。据调查,全县村庄建设用地面积7880.75hm2,村人均占有256m2,远远超出国家规定的人均最高150m2的标准。特别是县域北部地区,村庄用地粗放,闲置浪费土地现象普遍存在。随着工业化、城镇化进程加快,村民外出经商、进城创业居住的明显增多,农村中出现了较多的闲置房。(2)村庄建设违法占地逐渐增多。近年来,博兴县个体经济快速发展,用地需求也大量增加,部分村庄建设建新不拆旧、超占、多占宅基地;乱占耕地,尤其是在沿街沿路交通便利地段,违法建起了大量商住两用房。 相似文献
113.
Zheng Yi 《中国海洋湖沼学报》1998,16(4):369-372
Hypoglossum fujianensis sp. nov. is an epiphytic alga in the intertidal zone. Plants are light red, 0.9–2 cm high. Margin of branches gives rise
to uniseriate hair-like rhizoids, formed outward from the fusion of the second-and third-order cells. Blades are single layered
(except the midrib) and uncorticated. Tetrasporangial sori are formed on the middle part of blades. The globular tetrasporangia
are developed from lateral pericentral cells.
Project 39391800 supported by the NSFC. 相似文献
114.
介绍了中国地壳运动观测网络中的 GPS数据结构 ,对 GPS及其他观测数据的数据转换、数据传输、数据处理、管理及数据共享等工作流程作了详细说明。 相似文献
115.
按内波假说的观点,讨论了典型板内地震即中国大陆地震的成因机制,认为造成地壳厚度分化的内波运动依靠地壳厚度差异中蕴藏的重力位能,推动地壳物质运动形成各种类型的板内地震。研究了全球地震活动的纬度分布特点以及地震活动与潮汐作用及大陆分布的联系,指出:外动力地质作用强烈的大陆因剥蚀、搬运和沉积以及负载重分布,使大陆地区始终达不到重力均衡,成为地壳运动的活动区,因而陆壳“地震能量发射强度”曲线具有类似于潮汐剪应力纬度分布的两极衰减、南北对称的特性。文中还探讨了深震及和达—贝尼奥夫带的成因,克服了用俯冲板块解释这一现象的困难。 相似文献
116.
数字化精密水准测量仪器在水准及形变测量领域中起着极其重要的作用,而对数字水准仪的计量检定工作是使其正常运行的前提,针对其检定项目室内化的难题,介绍了一种国产新型数字水准仪的室内检定装置. 相似文献
117.
依据Chapman正常电离层理论,构造Chapman剖面函数加权投影函数,给出VTEC三角多项式模型,并以武汉站2005年1月1日观测数据进行实例解算,分析电离层延迟f-3项、电离层单层高度、电离层投影函数形式等对电离层延迟的影响. 相似文献
118.
ZHANGXue-qin GEQuan-sheng ZHENGJing-yun 《中国地理科学(英文版)》2003,13(3):207-215
How land-cover has been changed by human use over the last 300 years is one of the five overarching questions guiding the Land-use/Cover Change (LUCC) Science/Research Plan. China has variety of historical docu-ments providing unique data superiority. So the characteristics of farmland area in Shandong Province during the Qing Dynasty (1644-1911) are summarized firstly: 1) the rising trend of farmland area was striking; 2) farmland area had re-markable fluctuation; 3) farmland area per capita decreased dramatically; 4) wasteland reclamation index increased rapidly. Then, the driving forces of farmland area change are analyzed. It is concluded that natural and human factors are jointly influential. Among the driving forces, human dimensions are the main factors of farmland area change,which direct the general tendency of the changes mentioned above. And the natural factors influence the stability of farmland area as well. Variation of the natural factors would act as the major contributory factor to farmland area change during years or periods of abrupt climatic changes, or during the intensive occurring periods of natural hazards.Besides, the passive aspects of human factors, such as war chaos also influenced the fluctuation of the farmland area.This research indicates that it is feasible to study the land-use/cover change by Chinese historical literatures, which has huge potential to provide a comprehensive picture of the growing dominance of human land-use and land-cover pat-terns that can be used in many global change research oroiects. 相似文献
119.
Dehydration melting of solid amphibolite at 2.0 GPa: Effects of time and temperature 总被引:3,自引:0,他引:3
ZHOU Wenge XIE Hongsen LIU Yonggang ZHENG Xiaogang ZHAO Zhidan & ZHOU Hui . Laboratory of Material in the Earth’s Interior Institute of Geochemistry Chinese Academy of Sciences Guiyang China . Department of Geology China University of Geosciences Beijing China . Department of Geology Peking University Beijing China 《中国科学D辑(英文版)》2005,48(8):1120-1133
The dehydration melting of the natural rock at high pressure is important to investigating the magma formation in the earth’s interior. Since the 1970s, a lot of geological scientists have paid more atten- tion to the dehydration melting of the natural rock[1―5]. Previous experiments of dehydration melting and observations of fieldwork argued that the dehy- dration melting of the rock was probably the most important fashion for the melting of the lower crust rock[6―12]. The genesis of most … 相似文献
120.
The effect of biological soil crusts of different successional stages and conditions on the germination of seeds of three desert plants 总被引:1,自引:0,他引:1
Biological soil crusts greatly affect soil surface properties, which, in turn, may alter seed germination of vascular plants. We investigated the effects of two types of biological soil crusts (moss crust and algal crust) at different ages on the seed germination of Bassia dasyphylla and Artemisia ordosica. We also investigated the effects of crust conditions (living crust and dead crust) on seed germination of B. dasyphylla, A. ordosica and Eragrostis poaeoides. The presence of both algal and moss crusts significantly enhanced the germination of B. dasyphylla and A. ordosica compared with uncrusted soil. Crust age had no significant effect on the germination of either B. dasyphylla or A. ordosica for both moss and algal crusts. Germination of B. dasyphylla differed significantly between moss and algal crusts, but germination of both A. ordosica and E. poaeoides did not. Germination of A. ordosica, E. poaeoides and B. dasyphylla was significantly higher on living algal crust than on dead crust and uncrusted soil, while living moss crust enhanced the germination of both A. ordosica and B. dasyphylla but had no significant effect on E. poaeoides. 相似文献