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991.
设计了一种平三角形修正算法来修正TIN模型中可能出现的平三角形区域。该算法通过对由平三角形组成的区域进行分类,并针对不同的平区域采用交换边、增加点甚至不处理的修正方法,同时对由于等高线数据错误产生的一些特殊情况进行了分析处理。实验结果表明,该算法能够去除约束型狄洛尼三角网中所有应修正的平三角形,并生成对地形描述更为精确的三角网。  相似文献   
992.
李和平 《矿物学报》1998,18(1):80-83
以黄铁矿为例,通过导电性矿物的力学-电化学相互作用实验,得出:导电性矿物的电极电位与弹性轴压应力是较好的负线性相关关系。以此为基础,通过电化学理论分析,得出:地壳浅部与溶液接触的导电性矿物颗粒内部存在各种各样的应力原电池,通过应力原电池过程,压溶作用得以实现。导电性矿物应力原电池引起压涛作用的发现,无疑对诸如构造地球化学、地电化学甚至湿法冶金等领域的有关研究具有重要意义。  相似文献   
993.
油气运移滞后效应是指油气从烃源岩中生成并排出的时间早,而聚集成藏的时间晚,油气经历了长时间长距离运移,已聚集成藏的油气相态与成熟度低于现今烃源岩成熟演化的现象.这种油气运移滞后效应在东部新生代陆相断陷盆地中普遍存在,在斜坡带表现最为明显.通过利用地球化学分析,平衡剖面技术、盆地模拟、包裹体分析等手段,对渤海海域莱州湾凹...  相似文献   
994.
黄沙河地区位于新疆东昆仑西段南缘,属于昆南增生杂岩带,研究区内出露大面积下石炭统托库孜达坂组,为了厘定区内托库孜达坂组时代并对其沉积环境进行分析,本文在详细的野外地质调查基础上,通过地层层序学、岩石学及古生物学研究,将新疆东昆仑西段黄沙河地区托库孜达坂组分为下段碎屑岩段和上段碳酸盐岩段,将其时代厘定为早石炭世,结合区内碎屑岩粒度特征及放射虫化石特征,确定该套地层的沉积环境为半深海滨浅海环境。  相似文献   
995.
黄土高原干旱指数分析   总被引:12,自引:0,他引:12  
采用田间持水量差额与土壤最大有效含水量的比值作为干旱指数,描述了黄土高原的干旱规律。在此基础上,根据年干旱月数,把黄土高原地区划分为5种干旱型,并提出了各干旱型的农业生产防旱和抗旱措施。  相似文献   
996.
This work restored the erosion thickness of the top surface of each Cretaceous formations penetrated by the typical well in the Hari sag, and simulated the subsidence burial history of this well with software BasinMod. It is firstly pointed out that the tectonic subsidence evolution of the Hari sag since the Cretaceous can be divided into four phases: initial subsidence phase, rapid subsidence phase,uplift and erosion phase, and stable slow subsidence phase. A detailed reconstruction of the tectonothermal evolution and hydrocarbon generation histories of typical well was undertaken using the EASY R_0% model, which is constrained by vitrinite reflectance(R_0) and homogenization temperatures of fluid inclusions. In the rapid subsidence phase, the peak period of hydrocarbon generation was reached at c.a.105.59 Ma with the increasing thermal evolution degree. A concomitant rapid increase in paleotemperatures occurred and reached a maximum geothermal gradient of about 43-45℃/km. The main hydrocarbon generation period ensued around 105.59-80.00 Ma and the greatest buried depth of the Hari sag was reached at c.a. 80.00 Ma, when the maximum paleo-temperature was over 180℃.Subsequently, the sag entered an uplift and erosion phase followed by a stable slow subsidence phase during which the temperature gradient, thermal evolution, and hydrocarbon generation decreased gradually. The hydrocarbon accumulation period was discussed based on homogenization temperatures of inclusions and it is believed that two periods of rapid hydrocarbon accumulation events occurred during the Cretaceous rapid subsidence phase. The first accumulation period observed in the Bayingebi Formation(K_1 b) occurred primarily around 105.59-103.50 Ma with temperatures of 125-150℃. The second accumulation period observed in the Suhongtu Formation(K_1 s) occurred primarily around84.00-80.00 Ma with temperatures of 120-130℃. The second is the major accumulation period, and the accumulation mainly occurred in the Late Cretaceous. The hydrocarbon accumulation process was comprehensively controlled by tectono-thermal evolution and hydrocarbon generation history. During the rapid subsidence phase, the paleo temperature and geothermal gradient increased rapidly and resulted in increasing thermal evolution extending into the peak period of hydrocarbon generation,which is the key reason for hydrocarbon filling and accumulation.  相似文献   
997.
目的:运用中医传承计算平台(V3.0)分析中医药治疗肺癌伴恶性胸腔积液的用药规律。方法:计算机检索2000年1月1日至2022年2月28日中国知网(CNKI)、万方数据(WANFANG DATA)、维普中文科技期刊数据库(VIP)中关于中药复方治疗肺癌伴恶性胸腔积液的文献,分析中药的性味归经、功效、频次、药物组合、关联规则及聚类等。结果:共纳入文献98篇,处方103首,中药197味。频次≥20次的中药有18味,排前10位的依次为葶苈子、茯苓、白术、黄芪、大枣、甘草、泽泻、桂枝、半夏、薏苡仁。四气以寒、温、平为主;五味以甘、苦、辛为主;归经以肺、脾、胃经为主。排前3位的功效依次为补虚、利水渗湿、化痰止咳平喘。用药频次≥20次的中药组合有37组,排前4位的依次为茯苓-葶苈子、白术-茯苓、茯苓-黄芪、大枣-葶苈子。支持度≥25%的核心药物为黄芪、白术、茯苓、甘草、葶苈子、大枣、桂枝、泽泻。中药聚类分析提取到4个核心组合。结论:肺癌伴恶性胸腔积液多属晚期,以气血阴阳俱虚为本,饮停胸胁为标,病机多虚实夹杂。中医药治疗此病多以甘温益气补虚治本,苦寒泻肺利水治标,同时兼以温阳化气。  相似文献   
998.
Gu  Hong-lu  Guo  Hai-yan  Liu  Zhen  Li  Fu-heng  An  Wan-bo  Li  Peng 《中国海洋工程》2020,34(2):151-161
In order to investigate the effect of internal friction of umbilical cable on its vortex-induced vibration(VIV)responses, the experimental study on VIV of bond umbilical cable(BUC) and un-bond umbilical cable(UBUC) was carried out in an experimental tank. A current generator in the laboratory simulated the uniform current, and the current velocities were observed in real time by using a Doppler Velocimeter. In addition, different sizes of top tension were applied to the umbilical cable model. The VIV responses of the umbilical cable model were measured by using Fiber Bragg grating(FBG) strain sensors. The displacement responses of umbilical cable model were reconstructed based on the experimental strain data processed by modal superposition method. In this paper, the traveling wave characteristics, the spatial-temporal distribution characteristics of frequency and fatigue damage of the BUC and UBUC under VIV are studied. The experimental results show that there are obvious differences between BUC and UBUC in the response characteristics of VIV. The UBUC appears the traveling wave sooner than BUC, but its standing wave characteristics are more obvious than those of BUC at high velocities. Compared with BUC, the spatial-temporal distribution of UBUC frequencies appears wide-band distribution sooner, but has narrower bandwidth in the "lock-in" state. The level of fatigue damage of BUC was approximately the same as that of UBUC.  相似文献   
999.
1000.
China′s bid for the 2022 Winter Olympic Games will promote rapid development of domestic ski tourism. More than 10 provinces in the northern China list ski tourism as a new source of growth in the tourism industry. Formulating a scientific evaluation system is an important foundation for ski resort development. By referring to the conditions of existing international ski resorts, a comprehensive index system for evaluating ski resort development was developed based on natural factors, human factors, athletic sports, and popular ski tourism. The system was composed of one target layer, two indices, seven sub-indices and twenty-five basic indices. Based on data collected during a field investigation in 2012 and on a statistical model, the development conditions of the following ski resorts were quantified: Yabuli Ski Resort in Heilongjiang Province and Beidahu Ski Resort in Jilin Province in Northeast China, Wanlong Ski Resort in Hebei Province and Nanshan Ski Resort in Beijing in the northern China, and Silk Road International Ski Resort in Uygur Autonomous Region of Xinjiang in the northwestern China. The resulting index values of development conditions at Beidahu, Yabuli, Wanlong, Nanshan, and Silk Road International Ski Resorts were 0.304, 0.278, 0.270, 0.214, and –0.025, respectively. Various natural and human factors exert positive and negative effects on the development potential of ski resorts. The development conditions of the five ski resorts were inferior to those of first-class international resorts. Therefore, the development conditions of the five ski resorts should be improved with future construction.  相似文献   
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