共查询到20条相似文献，搜索用时 15 毫秒
1.
干旱盆地地下水排泄区以蒸发为主要排泄方式．导致水环境发生恶化，从而引发出一系列的环境问题。本文以吐哈油田南湖水源地建设为例，通过对浅层潜水和深层承压水之间的水力联系的分析，初步探讨了由开采承压水而引起的咸水下移、浅层咸水淡化以及地下水环境得以改善等问题。 相似文献
2.
Air DTH hammer has been successfully applied in minor-caliber solid mineral exploration,water-well drilling and other drilling areas.In order to expand the applications of the technology,the authors further studied the principle and analyzed the mechanism of reverse circulation drilling technique with air DTH hammer to get the perfect assembles of equipments by optimizing working parameters.No parameter seemed more important than the air volume because it could maintain the working performance stability.The minimum air volume is related to the parameters such as depth and pressure,which was calculated under the actual conditions.It was solved for the air injection flow tables of the air DTH Hammer working at the different pressures.According to the data tables,operators could adjust the air volume to meet the demand on this technique,which had a realistic guiding significance.So it could build up a set of systematic and complete hi-technique. 相似文献
3.
IIWr~IOWThesedimentarycharacteristicsofdebrisflowcanreflectthecompoSition,fluidtypeandsedimentaryprocess.ThescholarswhostudymoderndebrisfloWinChinagenerallyclassifydebrisflowbythemethodofviscositywithfloWpattern.SeveraltypicalschemesareshowninTable1,inwhichthemethodofunitweight(fluiddensityinunitvolumet/m3)isusedandfluidunitweightisthoughttobethedirectproPOSitiontotheviscosityofdebrisflow(Wu,1990).Ithasbeenprovedbyhydrcrmechacsthatnon-cohesivedebrisf1OwfollowsBagnoldgranular'flowmedel(B… 相似文献
4.
Study on the transient expression of GUS gene at different growing stage ofChlorella ellipsoidea using high velocity microprojectiles, the effects of osmosis, the distance between microprojectile and target cell, bombardment times, are reported in this paper. The results showed thatC. ellipsoidea in exponential phase has higer level of transient expression and that treatment with osmosis can improve the GUS transient expression notably. The effect of distance or bombardment times was not observed.
相似文献5.
一种基于卷积的正弦波频率稳定度测量方法 总被引：1，自引：0，他引：1
提出了通过离散卷积实现对频率稳定度的测量,介绍了该方法的原理和实现过程,并且与通用的硬件频率测量仪器进行比较,结果表明,与仪器测量频率稳定度的方法相比,此方法灵活简单,测量精度和仪器测量结果一致性较好. 相似文献
6.
Recent observations and modeling study about sea fog over the Yellow Sea and East China Sea 总被引：1，自引：0，他引：1
ZHANG Suping 《中国海洋大学学报(英文版)》2012,11(4):465-472
This review presents some of the latest achievements in sea fog research,including fog climatology,fog structure in the marine atmospheric boundary layer,and numerical simulations and forecasting of fog.With the development of atmospheric observational techniques and equipments,new facts about sea fog are revealed.The mechanisms involved in the formation,development and dissipation of sea fog are further explored with the help of advanced atmospheric models. 相似文献
7.
为认识构造对五宫煤矿瓦斯赋存的控制,分析了瓦斯地质演化特征,探讨了构造样式及组合对瓦斯赋存的控制。研究表明,煤系沉积后发生两次生气作用,生成了较多瓦斯。断层以逆断层为主,封闭性较好;煤层受断层影响而发生结构变形,可吸附更多瓦斯。断层使矿井处于相对封闭的水文地质单元中,阻碍了瓦斯的逸散。褶皱受断层切割多呈单斜构造,瓦斯顺层向上逸散受断层封堵。研究区构造封盖层组合类型为褶皱逆断层类型,盖层透气性较差,有利于瓦斯的保存。 相似文献
8.
LAN Kai YAN Taining. Drilling Engineering Technology Institute Zhongyuan Petroleum Exploration Bureau Puyang Henan China . Engineering Faculty China University of Geosciences Wuhan China 《东北亚地学研究》2009,(3):174-178
Drilling fluid is a common flushing medium used in pile foundation, geological drilling and petroleum drilling. Study on ultrasonic propagation properties in drilling fluid is of vital importance, not only for developing equipments to non-contact measuring concrete casting level for bored pile, but also for developing equip- ments considering drilling fluid as signal channel. The existence of clay particles makes the ultrasonic propagation and attenuation in drilling fluid much different from pure water. In order to know the relation among ultrasound frequency, slun-y density and depth, a series of laboratory experiments about ultrasound propagation in water-based bentonite slurry were finished. Wavelet method was adopted to process the gained original waves of ultrasonic propagation in slurry, so we knew the velocity and attenuation coefficient of ultrasound propagated in different drilling fluids with different density. The first group experiments shows that with density of drilling fluid increase, ultrasonic velocity will decrease but attenuation coefficient will increase if ultrasonic frequency keep constant. The second group experiments shows that the power of ultrasound will intensify in small bore hole, the attenuation coefficient is much smaller than theoretical value. 相似文献
9.
南北地震带南段莫霍面局部特征差异大,引用Parker-Oldenburg迭代反演算法分别在常密度模型和变密度模型下对该地区莫霍面进行反演研究。结果表明,变密度和常密度模型下南北地震带南段莫霍面总体形态特征基本一致,变密度模型反演结果更为精细,在高山地区变密度反演结果偏深。南北地震带南段地区攀枝花幔隆与东川幔陷特征显著,深部作用对区域构造地震活动具有重要影响。 相似文献
10.
大气降水对数字化地倾斜观测干扰特征分析 总被引：5，自引：0，他引：5
对武汉基准地震台倾斜固体潮观测资料的研究表明,固体潮曲线畸变是降雨渗透使基岩膨胀的结果。降雨对记录曲线的影响主要表现在:1)时间上具有同步效应。降雨发生后倾斜仪的NS分量发生南倾,EW分量发生东倾;2)量级上受降雨干扰严重的主要为NS分量,EW分量受干扰程度较轻;3)垂直摆受降雨的干扰程度比水管仪的大。 相似文献
11.
JIN Huijun SUN Guangyou YU Shaopeng JIN Rui HE Ruixia 《中国地理科学(英文版)》2008,18(1):62-69
Recently, the degradation of permafrost and marsh environments in the Da and Xiao Hinggan Mountains has become a great concern as more human activities and pronounced climate warming were observed during the past 30 years and projected for the near future. The distr/bution patterns and development mechanisms of the permafrost and marshes have been examined both in theories and in field observations, in order to better understand the symbiosis of permafrost and marshes. The permafrost and marshes in the Da and Xiao Hinggan Mountains display discernible zonations in latitude and elevation. The marsh vegetation canopy, litter and peat soil have good thermal insulation properties for the underlying permafrost, resulting in a thermal offset of 3 ℃ to 4℃ and subsequently suppressing soil temperature. In addition, the much higher thermal conductivity of frozen and ice-rich peat in the active layer is conducive to the development or in favor of the protection of permafrost due to the semi-conductor properties of the soils overlying the permafrost. On the other hand, because permafrost is almost impervious, the osmosis of water in marsh soils can be effectively reduced, timely providing water supplies for helophytes growth or germination in spring. In the Da and Xiao Hinggan Mountains, the permafrost degradation has been accelerating due to the marked climate warming, ever increasing human activities, and the resultant eco-environmental changes. Since the permafrost and marsh environments are symbiotic and interdependent, they need to be managed or protected in a well-coordinated and integrated way. 相似文献
12.
Spatial-temporal pattern and formation mechanism of county urbanization on the Chinese Loess Plateau
《山地科学学报》2021,(4)
Urbanization is a comprehensive and complex socioeconomic phenomenon that plays an influential role in promoting global socioeconomic development. The Loess Plateau region is an important part of the China's ecological security pattern, and occupies an important position in the implementation of China's new-type urbanization strategy and the realization of the urban dream. The characteristics of the staged changes and regional differentiation of urbanization in the area from 1990 to 2018 were studied with focus on regions and subregions by selecting 341 county-level administrative units on the Chinese Loess Plateau as the research area, and employing partition analysis and geographic detector methods. This revealed the formation mechanism of the spatial differentiation pattern of urbanization on the Loess Plateau. We found that the urbanization of the Loess Plateau,previously in a slow growth phase, entered the accelerated development phase, presenting a macro pattern of high rates of urbanization in central and eastern areas and low rates in western areas. The formation of the regional differentiation patterns of urbanization on the Loess Plateau were the combined results of natural geographical and socioeconomic factors. Among these factors, the interaction of any two factors had a stronger impact on regional urbanization patterns than a single factor, which was specifically manifested as nonlinear or bi-factor enhancement effects. The findings of this paper may provide a theoretical reference and scientific basis for the scientific promotion of healthy urbanization on the Chinese Loess Plateau and the ecologically fragile areas of developing countries around the world. 相似文献
13.
利用可实例化的智能线程池技术,通过两个线程池分别实现了前兆数据的并行数据采集与数据的多目标入库,可自动实现对最近巧天内的数据进行检测与采集,采集仪器的数量由原来的几台、十几台提高到上千台,大大提高了地震前兆数据的采集效率;通过数据的多目标入库,数据由台站到区域中心以及国家台网中心的同步速度也得到很大提高. 相似文献
14.
随着地籍管理科技发展,铁路用地地籍管理在引入国家大地统一坐标系的测量技术手段的同时,为满足铁路用地线状分布特点和日常管理的需要,仍然保留了独立坐标系统。而铁路运营设备的不断更新和技术装备的不断提高,铁路线路设备发生了较多拨移、变线或改道,作为确认铁路地界线位置的基准线,铁路线路的变化,对快速准确地查找铁路地界线产生了直接影响。为此,针对铁路用地参照坐标的变化情况及调整方法进行了深入调查研究,提出了可行性建议。 相似文献
15.
１ＰＲＯＣＥＳＳＯＦＤＥＳＥＲＴＩＦＩＣＡＴＩＯＮＡＮＤＩＮＦＬＵＥＮＣＥＯＦＰＨＹＳＩＣＡＬＥＮＶＩＲＯＮＭＥＮＴＡＮＤＨＵＭＡＮＡＣＴＩＶＩＴＹＩＮＬＩＮＧＷＵＹＡＮＣＨＩＲＥＧＩＯＮＴｈｅｄｅｓｅｒｔｉｆｉｃａｔｉｏｎｈａｚａｒｄｉｎＬｉ... 相似文献
16.
城镇发展适宜性研究有助于了解城镇发展的优势条件,为确定城镇建设规划的扩展方向提供依据。在北极与亚北极开展研究对中国开展在城镇化、重大基础设施、廊道建设方面的国际合作有重大意义。本文使用多源数据,在采样的基础上利用逐步法的思想进行变量筛选,共筛选出5个显著指标,用logistic方法拟合出最终的模型进行城镇发展适宜性评价,最终得到研究区城镇发展适宜性分级图。研究结果表明：筛选后的显著指标对研究区城镇分布的影响作用大小排序为,温度（正向）、交通网密度（正向）、海拔高度（反向）、人口密度（正向）、距港口距离（反向）;温度、交通网密度、海拔高度、人口密度、距最近港口距离增加1个单位,城镇发展的几率分别比原来增加了38.4%、16.7%、9%、0.4%、0.1%;研究区的Ⅰ（不适宜）、Ⅱ（中度适宜）、Ⅲ（高度适宜）的城镇发展适宜性均值分别为0.03、0.16、0.68（分别约占研究区总面积的76.82%、21.82%、1.37%）;城镇发展适宜性总体呈现出随纬度升高而降低、随经度升高而增加的趋势,适宜城镇发展的气候地理条件是温带大陆性湿润气候带和温带海洋性气候带以及平原与低地地区;研究区的城镇发展适宜性俄罗斯西北部为0.08、瑞典为0.07、芬兰为0.06、挪威为0.03。俄罗斯西北部城镇发展适宜性整体上呈现出北低南高,南部呈现两边高中间低的空间布局;瑞典呈现出西北低东南高,沿海大于内陆的空间布局;芬兰呈现出北（高原）低南（沿海）高,中部次高的空间布局;挪威呈现出南部沿海高,西部沿海次高,其他区域低的空间布局。 相似文献
17.
曹章庆 《广东海洋大学学报》2007,27(2):78-82
小山词中主要存在着伤感与虚幻两种情感心态。这两种情态,在内涵方面表现为怀才不遇、蹉跎沦落或苦恋离情、风流云散的伤感;以及“欲而不得”或“得而复失”的虚幻。而这种虚幻,主要是通过“梦幻”、“醉酒”两种方式和“空”等字面加以表达,跟佛禅在精神体验方面又有某种相通之处。 相似文献
18.
红外遥控在电子产品中有着越来越广泛的应用.介绍了用凌阳SPCE061A系列单片机实现电子产品的红外遥控发射. 相似文献
19.
现代化气象探测设备种类繁多、数量庞大,传统的人工纸质化管理模式已不能满足气象装备保障的智能化管理需求。采用基于B/S架构的Web技术建立气象装备保障智能信息管理系统,实时、准确、高效的完成气象装备的库存管理、需求管理、通知预警、统计查询及系统日志管理等功能,为气象业务人员的检定维修、计划采购、需求申请等工作提供一体化平台,极大地提高了设备管理使用的工作效率并降低数据出错率。系统也是现代气象信息化管理系统中的重要组成部分。 相似文献
20.
Tatiana V. Selivanova 《世界地质(英文版)》2006,9(2)
Hankaisky Region is the most densely populated and economic developed part of the Primorskiy Krai. It is promoting development of dangerous geological processes there. In the article the reasons of formation and intensive development in Hankaisky Region of the following dangerous geological processes lateral, winder and ground erosive, sill, floods, taluses, bogging, slope wash, karts, rebound of ground are considered. 相似文献