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1.
According to the theory of elastic mechanics half plane, the mechanical model of roof overburden failure is established. Based on the numerical simulation software FLAC3D, the failure process of roof overburden in 1308 working face is numerically simulated according to the orthogonal experimental design scheme. Matrix analysis and variance analysis are used to analyze and calculate the simulation results to determine the sensitivity of the main control factors to the failure height of overlying rock of mining roof. The results show that: (1) with the increase of mining depth and the advancing distance of working face, the subsidence of roof overburden increases. (2) The order of influence of main controlling factors on roof overburden failure height is: mining depth > working face length > internal friction angle > mining thickness > coal seam dip angle > cohesion > tensile strength. (3) Variance analysis showed that the mining depth height was significant, the working face length and internal friction angle were significant, and the significance of working face length was slightly greater than that of internal friction angle, and other factors were not significant.
相似文献2.
Alentiana has only one member, A. aurantiaca (Verrill, 1885), commensal with sea anemone (Bolocera tuediae). Here, Alentiana palinpoda sp. nov., a second member in the genus Alentiana (subfamily Lepidastheniinae), a new commensal polynoid is described, based on a specimen collected from a deep-water seamount in the Northwest Pacific Ocean. The new species is characterized by large elytra that completely cover the dorsum and are present in every third segment in the posterior regions. Neuropodia are truncated, with two types of neurochaetae;supraacicular chaetae toothed on one side with a slightly inflated end, and subacicular chaetae that are heavy and smooth; the prechaetal lobe is larger than the postchaetal lobe, with the ventral part rolling upward and 相似文献
3.
确保减碳的首要任务是定量测度化石能源消费碳排放的增量影响因素及其大小。为分析北京市1997-2007年的碳排放增量,本文构建了一个扩展的(调入、进口)竞争型经济—能源—碳排放投入产出模型,从整体特征、不同产业、工业行业3个方面,对1997-2007年北京能源消费的碳排放增量进行了结构分解。分析发现:经济规模增长要素(消费、投资、调出和出口等)是拉动碳排放增长的主导因素,能源强度变动效应却是碳减排的决定性因素;在规模扩张因素中,消费和调出超过投资和出口,是碳排放增长的主要贡献者;2002以来新一轮"高碳"特征的工业化导致CO2排量呈急增之势;产业结构调整、三产比重最大使得服务业成为碳排放增长的最大部门,但工业排放的增长却后来居上;碳增排的重点行业是高能耗业,而碳减排的却是能源工业;两时段各效应在不同产业、不同工业行业的影响方向和大小不一。 相似文献
4.
主要采用有关统计年鉴中的就业人数数据,分别选用变异系数、空间基尼系数和区位商测算了长株潭城市群2003-2008年生产性服务业的空间分布差异程度和集聚程度.结果表明:就整个生产性服务业而言,空间分布较为分散,在全国的集聚程度也不高,但具有集聚发展的趋势;从不同城市看,长沙集聚程度最高,株洲和湘潭则相差甚远;从行业看,科学研究、技术服务和地质勘查业以及批发零售贸易业的集聚度较大,而金融业及交通运输、仓储和邮政业的集聚度很小,其它行业的集聚度居中;此外,信息传输、计算机服务和软件业的空间基尼系数连年下降.认为要使生产性服务业朝着更集聚的方向发展,应在空间分布和结构优化两个层面实行差异化的调控. 相似文献
5.
北京能源消费排放CO2增量的分解研究——基于IDA法的LMDI技术分析 总被引：3，自引：1，他引：2
采用IDA法的LMDI技术,全面实证研究了北京1995-2010年经济部门和生活消费因能源消耗排放二氧化碳增长的驱动因素,分析导致6大产业部门和生活消费的碳排放增量的各自效应。结论表明:拉动产业部门碳排放量增长的决定性因素是经济规模扩大,而促使碳排放减少的主要因素是能源强度降低,产业结构调整和能耗结构变化对产业碳排放变动的贡献较低;就行业而言,工业的碳减排成果最显著,其他服务业及交通运输、仓储与邮政业的增量明显;人口规模的持续扩大是导致生活消费碳排放量增加的主因,人均能耗强度加大紧随其后,但碳排放系数和生活能耗结构的变化却对减碳贡献不大。最后,针对上述分析结果,提出了北京未来节能减碳的简明政策建议。 相似文献
6.
CHANG Jiang LI Jingbao LU Dianqing ZHU Xiang LU Chengzhi ZHOU Yueyun DENG Chuxiong 《地理学报》2010,20(5):771-786
Based on the measured hydrological data from 1951 to 2008, the chain hydrological effect between Jingjiang River and Dongting Lake is analyzed by comparative method after the Three Gorges Project operation. The result indicates that 1) the scouring amount in Jingjiang River made up 78.9% of the total from Yichang to Chenglingji, and its average scouring intensity was higher than the latter; 2) the water and sand diversion rates at the three outlets of the Jingjiang River were reduced by 2.33% and 2.78% separately; 3) the proportion of multi-year average runoff and sediment through the three outlets in the total into the Dongting Lake decreased by 7.7% and 24.4% respectively; 4) in Dongting Lake, the speed of sediment accumulation was lowered by 26.7%, in flood season, the runoff amount was 20.2% less than the multi-year average value, leading to seasonal scarcity of water year by year. The former prolonged the lake life, while the latter induced droughts in summer and fall in successive years, shortage of drinking and industrial water, shipping insecurity, as well as ecological problems such as decrease of birds and quick increase of Microtus fortis; 5) The multi-year average values of sediment and flood transporting capacity at the lake outlet were respectively increased by 26.6% and 3.7%, the embankments were protected effectively. Then, to adapt to the new change of the river-lake relation, some suggestions were put forward, such as optimizing further operation program of the Three Gorges Reservoir, reexamining the idea of river and lake regulation, and maintaining connection of the river and the lake. 相似文献
7.
2013年"菲特"台风影响期间,上海地区普降大暴雨。在降雨、风暴潮增水和上游来水的共同影响下,黄浦江、长江口、杭州湾潮位全线超警,特别是黄浦江上游部分测站最高潮位超历史记录,严重制约了流域排洪和区域排涝。为分析台风影响期间太湖流域上游来水对上海地区的影响,通过现场调查、统计分析和模型模拟等方法,计算分析台风影响期间太湖流域产水量、外边界进出水量、湖库河网调蓄量以及洪涝灾害严重地区的淹涝量等,从而计算太湖流域上游进入上海地区的水量,为上海地区的防洪减灾工作提供基础支撑。 相似文献
8.
The hydrological effect between Jingjiang River and Dongting Lake during the initial period of Three Gorges Project operation 总被引：2，自引：2，他引：0
Jiang Chang Jingbao Li Dianqing Lu Xiang Zhu Chengzhi Lu Yueyun Zhou Chuxiong Deng 《地理学报(英文版)》2010,20(5):771-786
Based on the measured hydrological data from 1951 to 2008, the chain hydrological effect between Jingjiang River and Dongting
Lake is analyzed by comparative method after the Three Gorges Project operation. The result indicates that 1) the scouring
amount in Jingjiang River made up 78.9% of the total from Yichang to Chenglingji, and its average scouring intensity was higher
than the latter; 2) the water and sand diversion rates at the three outlets of the Jingjiang River were reduced by 2.33% and
2.78% separately; 3) the proportion of multi-year average runoff and sediment through the three outlets in the total into
the Dongting Lake decreased by 7.7% and 24.4% respectively; 4) in Dongting Lake, the speed of sediment accumulation was lowered
by 26.7%, in flood season, the runoff amount was 20.2% less than the multi-year average value, leading to seasonal scarcity
of water year by year. The former prolonged the lake life, while the latter induced droughts in summer and fall in successive
years, shortage of drinking and industrial water, shipping insecurity, as well as ecological problems such as decrease of
birds and quick increase of Microtus fortis; 5) The multi-year average values of sediment and flood transporting capacity at the lake outlet were respectively increased
by 26.6% and 3.7%, the embankments were protected effectively. Then, to adapt to the new change of the river-lake relation,
some suggestions were put forward, such as optimizing further operation program of the Three Gorges Reservoir, reexamining
the idea of river and lake regulation, and maintaining connection of the river and the lake. 相似文献
9.
三峡水库调度运行初期荆江与洞庭湖区的水文效应 总被引：12，自引：1，他引：11
以1951-2008年实测水文资料为依据,运用对比方法,分析了三峡水库调度运行初期,荆江与洞庭湖区的连琐水文效应.结果表明:①莉江冲刷星占宜昌至城陵矶段的78.9%,其平均冲刷强度也远高于该河段;②三口分流比减少2.33%、分沙比减少2.78%;③三口多年平均入湖径流泥沙比依次减少7.7%及24.4%;④洞庭湖区淤积速率减缓26.7%、汛期水最较同期多年平均值偏少20.2%,使湖区连年季节性缺水,前者对延长湖泊寿命有利,后者酿成了连年性的夏秋连旱灾害、居民饮用水、生产用水和航运等水安全问题以及涉及到了珍禽鸟类数量和种类减少,东方田鼠种群数量极度膨胀等生态系统的稳定性;⑤湖口多年平均输沙泄洪能力增强了26.6%和3.7%,避免了溃垸决堤之灾.并认为,为适应新的江湖关系变化,必须进一步优化调整三峡水库调度运行方案,重新审视江湖治理的理念,维系江湖连通的纽带. 相似文献
10.
过去几十年太湖流域经济社会快速发展,但由于经济增长方式尚未根本转变,流域水循环系统遭到无序干扰和破坏,太湖水污染问题严重,水质型缺水问题突出,流域水安全面临巨大挑战. “引江济太”作为太湖流域水安全保障的关键措施和流域水环境综合治理的重要举措,自2002年启动实施以来,以丰补枯,增加流域水资源供给;以动治静,抑制太湖蓝藻大规模暴发,改善流域区域水环境;科学应对,保障突发水污染事件和重大活动期间供水安全,取得了显著的综合效益,社会各界予以了广泛关注. 本文基于监测数据和大量文献,在综述“引江济太”实践背景、过程和成效的基础上,重点围绕“引江济太”调度模式、水量水质保障、洪旱风险管控、调水事件驱动等进行了研究. 结果表明,“引江济太”通过试验探索回答了流域治理管理的一些关键科学问题,已经成为提升流域水资源和水环境承载能力的重要手段. 面对极端气候变化、流域水循环格局变化、保障长三角一体化高质量发展水安全新需求和挑战,建议“引江济太”实践中,探索多目标统筹协调调度、开展数字孪生太湖调水、促进流域骨干水网建设,实现”引江济太”综合效益最大化. 相似文献