共查询到20条相似文献，搜索用时 156 毫秒
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每年汛期,城市内涝频发,城市生产生活秩序受到严重破坏,民众生命财产遭受重大损失。国家虽然对此给予了大量投入,依然收效甚微。面对严重自然灾害,政府部门无能为力,党政领导痛心疾首,城市民众怨声载道,新闻媒体大声呼吁。真的是年年防涝年年涝,年年受淹年年淹,年复一年何时了,民众何日得安颜!今年入汛,北京、成都、武汉、广州、深圳、长沙、南京、杭州、南昌等诸多城市再次受到了暴雨袭击,内涝成灾。"城市观海"、"水上机场"、"地铁瀑布"等一时成为网友的笑谈。 相似文献
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4月8日的海南三亚,大海、蓝天、椰树、花卉相互辉映,风景秀美,春色宜人。在总局领导的亲自关怀指导下,《中国煤炭地质》杂志首届理事会会议暨煤炭地质科技论坛。在此地举行。经过与会的各级领导、专家学者和会务工作人员的紧张而辛勤工作,圆满地完成了各项议程,收到了预期效果。对此,大家普遍反映,会议暨论坛时间虽短。但组织周密、议题鲜明、内容丰富、形式新颖、别开生面,收获颇多、不虚此行。 相似文献
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壮族可能是最为器重过节的一个民族了。在一些壮族地区,几乎每个月都有节过。著名节日有春节、三月三、七月十四等。如果按顺序排列,壮族最隆重的节日是春节,其次是七月十四鬼节、三月三、清明、八月十五中秋,此外,还有青蛙节、牛魂节、端午节、重阳节、尝新节、冬至节、送灶节等等。 相似文献
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近日,葫芦岛市深入开展2010年度土地卫片执法检查工作。
一是切实加强对卫片执法工作的组织领导。各级国土资源部门主动与纪检监察、公安、司法、规划、建设等部门的协调配合,成立了专门的土地卫片执法检查办事机构,主要负责人亲自抓,做到机构落实、人员落实、经费落实。执法监察、地籍、规划、耕地、利用等业务部门合理分工,各司其职,各负其责,密切配合,共同完成土地卫片执法检查的各项工作任务。 相似文献
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9月24日,中国智慧城市研究院签约仪式在聊城大学举行,国家测绘地理信息局地名研究所、聊城市人民政府、聊城大学三方共同签署了中国智慧城市研究院合作协议。国家测绘地理信息局副局长李维森,山东省测绘地理信息局局长吴玉海出席仪式。聊城市委副书记、市长王忠林,市委常委、常务副市长耿涛,市委常委、副市长张旋宇,副市长冯艺东、市政府秘书长马骏,副秘书长、市国土资源局局长靳凤莲,副秘书长魏天山,聊城大学党委副书记、校长马春林等学校领导出席签约仪式或陪同活动。签约仪式上,李维森、吴玉海、王忠林、马春林共同为中国智慧城市研究院揭牌。 相似文献
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北半球高纬海冰主要气候特征的全球海冰气耦合模式数值模拟 总被引：5，自引：0，他引：5
利用一个全球海冰气耦合模式对北半球高纬海冰的主要气候特征进行了数值模拟。结果表明 ,模拟结果中海冰的季节变化特征合理 ,冬季海冰的主要地理分布特征都模拟得很好 ,但夏季北冰洋内部靠近欧亚大陆部分边缘海区海冰密集度模拟得偏大。模拟结果中 ,北半球高纬地区冬季海冰密集度具有显著的年际变化 ,变化最显著区域位于格陵兰海 ,其次是巴伦支海 ,这些特征均与观测结果一致。对这个海冰气耦合模式在北半球海冰平均气候状况、季节变化和年际变化方面模拟能力的检验结果表明 ,当前的研究工作为下一步进行长期变化趋势的模拟打下了基础。 相似文献
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阵列声波测井信号的时频局域相关能量分析 总被引：1，自引：1，他引：0
提出了一种基于信号时、频局域相关能量的新的时-频信号分析方法——Rihaczek分布,对多极子阵列声波测井信号进行了分析。该方法有着比较明确的物理意义,对不同岩性、构造的响应具有很好的区分和识别能力。声波的Rihaczek分布对不同的岩性,以及由不同岩性组成的构造破碎带具有明显不同的表现特征。利用相应的模式识别方法,可以对这些岩性、构造进行有效的区分和识别。 相似文献
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Study of evaporation and recharge in desert soil using environmental tracers, New Mexico, USA 总被引：4，自引：0，他引：4
The purpose of this study is to investigate the rates and mechanisms of recharge and evaporation in soils of a desert environment
using two environmental tracers (chloride and oxygen-18). The profiles of chloride concentration and oxygen-18 enrichment
in soil-water, together with the depth distribution of water content in soil, reveal information about long-term recharge
and instantaneous evaporation processes without needing to know the physical properties of the soil. Three holes were hand-augured,
in different desert settings in southeastern New Mexico. The chloride concentration profiles were used, with the chloride
mass balance method, to estimate long-term recharge rates in these three holes as 0.5, 0.8, and 2.4 mm yr–1. Analysis using a bimodal flow and transport model shows that possibly 85% of the recharge occurs via movement of water through
preferred pathways in the root zone. Preferential flow was evident in all three sampling sites. Clay layers have a noticeable
effect on the development of water content distribution and thus on oxygen-18 enrichment and chloride concentration profiles.
The spatial variation in clay layering partly explains the variation in recharge rate estimates.
Received: 13 October 1995 · Accepted: 15 November 1995 相似文献
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对2016年全年颗粒物监测浓度数据进行统计分析,得到了安徽省颗粒物污染的空间分布、浓度和粒径,以及污染传输特征。结果表明,淮河以北、沿江和江淮之间、长江以南和皖南山区城市颗粒物污染随地理位置不同表现出明显的区域化特征,污染程度由北向南减轻,污染过程明显表现出由北向南逐步扩散传输的规律,污染程度越重,污染深入南方的范围越广,持续时间也越长。冬季污染较重的城市,上午出现明显的高浓度时段,全天变化为“双峰双谷”型。夏、秋季节夜间细颗粒物(PM2.5)浓度贡献比增加。PM2.5与PM10(可吸入颗粒物)质量浓度比值冬季最高,春季较低。污染重的城市冬季PM2.5占比高。 相似文献
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Jin-quan Jiang Quan-sen Wu Quan-lin Wu Pu Wang Chen Zhang Bin Gong 《Geotechnical and Geological Engineering》2018,36(6):3451-3466
In the coal measure strata, igneous rocks are often invaded, and their occurrence, size, and distribution form play an important role in mining safety. The breakage of hard and thick igneous rocks easily induces dynamic disasters, such as rock burst, mine seismicity, gas outburst, and surface subsidence, which seriously threaten mine safety production. In view of the working face with overlying hard and thick igneous rocks, the evolution characteristics of mining stress and energy distribution under hard and thick igneous rocks were investigated. Furthermore, the influence law of different horizons and thicknesses of igneous rock on overlying strata movement law, stress distribution, and energy distribution was analyzed based on FLAC3D numerical simulation. Results show that no evident subsidence of the overlying strata exists before the igneous rock is broken. Additionally, the subsidence amount of the overburden is suddenly increased after the igneous rock is broken, thereby showing significant mutability. Before the igneous rock breaks, a high stress area is formed around the goaf, and the stress concentration gradually increases with the increase of the mining scope. After the igneous rock breaks, the coal under high stress is prone to induce dynamic disasters under the action of strong dynamic load. However, the advanced abutment pressure and stored energy rapidly decreased. The accuracy of the numerical simulation is verified by field monitoring. Results of the study are of considerable significance for safe mining of working face under similar geological conditions. 相似文献
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The influences of solids concentration, molecular weight of dispersant, particle size and distribution, and temperature on the rheological behaviour of limestone slurries have been investigated. The results reveal that when the solids concentration of a limestone slurry (< 100 μm) is increased from 60 wt.% (35.71 vol.%) to 78.5 wt.% (57.49 vol.%), the rheological behaviour of the slurry is transformed from a weakly dilatant characteristic to a pseudoplastic one with a yield stress, which is in combination with a thixotropic property at a higher solids concentration (i.e., ≥ 75 wt.% or 52.63 vol.%). At a certain shear rate, the apparent viscosity and the relative viscosity of the slurry increase exponentially with solids concentration. The extrapolated Bingham yield stress increases rather sharply in a power-law form with increasing solids concentration when the solids concentration of the slurry is larger than 70 wt.% (i.e., 46.36 vol.%). An attainable maximum packing solids fraction (?m) is predicted as ?m = 64.6 vol.% at the certain limestone–water suspension system. A polymeric dispersant named Dispersant S40 with a molecular weight of 5500 appears most effective for the reduction of the apparent viscosity of limestone slurry due to its good electrosteric stabilization and effective avoidance of depletion flocculation. The smaller the particle size and the narrower the size distribution, the more evident the pseudoplastic property of limestone slurry is with a larger yield stress and a larger apparent viscosity at a given shear rate in the range of 12 to 1200 s− 1. Also, a statistic model describes a relationship between the particle size and distribution and the apparent viscosity of the slurries at a given solids concentration (i.e., 70 wt.% or 46.36 vol.%). However, a sufficient additive dosage of Dispersant S40 (i.e., ≥ 0.1 wt.%) significantly decreases or even eliminates the rheological differences of limestone slurries (apparent viscosities and extrapolated yield stresses) resulting from the difference in particle size and distribution. Besides, the apparent viscosity of limestone slurries decreases with increasing temperature in the range of 13 to 55 °C, regardless of the absence or the presence of Dispersant S40. 相似文献