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141.
INTRODUCTIONItwasgenerallyconsideredpreviouslythatthecorrosionofsteelinseamudwasnotserious.However,itwaslaterfoundthatthecorrosionrateofsteelinsomeseamudwashigherthanthatinseawater(King,1980;Sehmide,1982;Guoetal.,1997;Hou,1998).Therearesomereportsthatthecorrosionr…  相似文献   
142.
本文采用Lorenz(1960)系统,在只考虑初始误差及观测误差而不考虑模式误差的情况下,利用扩展卡尔曼滤波(Extended Kalman Filter)数据同化方法进行了数值模拟试验。数值试验的结果表明:扩展卡尔曼滤波数据同化方法对系统状态的估计有较好的改善作用,能有效的抑制估计误差的增长;加大观测频率,可以进一步改善数据同化的效果,使估计误差进一步减小;由于模式误差的存在,系统的不稳定能量会不断的累积,出现了估计误差的异常增长和计算的不连续现象,在模式预报方程中的均值演变方程加人二阶偏差纠错项,对控制估计误差的异常增长,进一步改善数据同化的效果有较明显作用。  相似文献   
143.
巷道作为矿山的重要组成部分,在矿山开发建设过程中发挥着重要作用,基于虚拟现实技术的巷道三维模拟能够为采矿工程、安全生产、施工、人员及设备管理等提供直观的数据展示和决策支持,其精确程度直接影响着矿山的工程质量与采选能力。本文主要探讨巷道三维建模数据组织方法,直壁拱形断面巷道三维建模的关键算法,并基于实验数据,利用OGRE三维引擎技术完成巷道三维自动建模,验证了数据组织和算法的有效性和优越性。  相似文献   
144.
媒介是传递信息的载体,传统意义上是指报刊、广播、电视等媒介,随着传播新技术的发展,出现了以互联网络、手机为代表的新媒介。与传统媒介相比,新媒介有其不同的涵义和特点,对政府信息公开工作产生着重要影响。本文从新媒介的概念和特点出发,分析了新媒介对政府信息公开的影响,阐述了新媒介环境下如何做好政府信息公开工作,最后提出在新媒介环境下对国土资源政府信息公开的几点思考和建议。  相似文献   
145.
The spatial and temporal variation of major ions (Ca2+, Mg2+, Na+, K+, , , and Cl) in Himalayan snow and ice is investigated by using two snow pits from the East Rongbuk glacier (28°01′N, 86°58′E, 6500 m a.s.l.), one snow pit from the Nangpai Gosum glacier (28°03′N, 86°39′E, 5700 m a.s.l.), one snow pit from the Gyabrag glacier (28°11′N, 86°38′E, 6303 m a.s.l.), and three ice cores from the Sentik (35°59′N, 75°58′E, 4908 m a.s.l.), Dasuopu (28°33′N, 85°44′E, 7000 m a.s.l.), and East Rongbuk (27°59′N, 86°55′E, 6450 m a.s.l.) glaciers, respectively. In general, the major ions show a significant seasonal variation, with high concentrations during the non-monsoon (pre-monsoon and post-monsoon) season and relatively low concentrations during the monsoon season. Monsoon precipitation with high local/regional dust loading related to summer circulation is possibly responsible for the high concentrations occurring sporadically during the monsoon season. The crest of the Himalayas is an effective barrier to the spatial distribution of Na+, Cl and concentrations, but not to the major ions associated with dust influx (e.g. Ca2+ and Mg2+). Atmospheric backward trajectories from the HYSPLIT_4 model used in identifying chemical species sourcing suggest that the major ions in the Himalayan snow and ice come mainly from the Thar Desert located in the North India, as well as West Asia, or even the distant Sahara Desert in the North Africa during the winter and spring seasons. This is different from the conventionally assumed arid and semi-arid regions of the central Asia. Factors, such as different vapor sources due to atmospheric circulation patterns and geographical features (e.g. altitude, topography), may contribute to the differences in major ionic concentrations between the western and eastern Himalayas.  相似文献   
146.
The key components of S. triqueter root exudates involved 4-oxo-pentanoic acid, succinic acid, glutaric acid, phthalate acid, citric acid, vanillic acid, myristic acid, pentadecanoic acid, decanoic acid, 14-methyl-pentadecanoic acid, hexadecanoic acid, octadecanoic acid and oleic acid, and the content of the water-soluble organic acids (citric acid, succinic acid and glutaric acid) significantly increased in pyrene and lead co-contaminated rhizosphere soil. These three water-soluble organic acids including citric acid, succinic acid and glutaric acid were detected as the specific root exudates of S. triqueter under stress of pollutants for pyrene and lead, so they were chosen as the research objects, and they were added into the bioremediation systems of pyrene and lead co-contaminated wetland soils. Compared with the control, the treatments added the three organic acids always improved the quantity of the bioavailable fraction of pyrene and lead in wetland soils and greatly influenced other chemical states of pyrene and lead fractions in the test concentration range. Under the 50 g kg?1 of organic acids concentration, the amount of the bioavailable fraction of pyrene and lead increased 41.0 and 872.7 % by citric acid, respectively. The enhancement of bioavailability of pyrene and lead in the wetland soil by adding organic acids generally decreased in the following order: citric acid > succinic acid > glutaric acid. Enhancing effects of organic acids on the bioavailability improvement of pyrene and lead is remarkable.  相似文献   
147.
张八岭地区变质地层序列与构造型式   总被引:6,自引:0,他引:6  
运用构造与地层相结合的理论和方法,通过对张八岭地区已完成和正在进行的10幅1:5万地质填图资料分析和典型地区的构造追踪,初步认为:北将军(岩)组自下而上分为三段,时代置于中元古代,获铅同位素年龄样值为1821±416Ma;西冷(岩)组自下而上分为三段,时代置于青白口纪。区内主要存在三期构造交形:早期为一系列呈NWW-近EW向的紧闭同斜褶皱,中期以韧性剪切带发育为特征,晚期以NNE向为主的宽缓褶皱。三期变形共同叠加,形成区内基本构造格架。并对变形机制作初步探讨。  相似文献   
148.
辽宁省宽甸县甬子沟滑石矿床分布于古元古界辽河群大石桥组三段的白云质大理岩中,矿床明显受控于北西向断裂,围岩蚀变以滑石化、透闪石化最为发育.矿床成因属中低温热液交代型层控矿床.依成矿地质条件和找矿潜力,寻找隐伏矿体、已知矿体外围是主要的找矿方向.  相似文献   
149.
The North Qilian orogenic belt is a typical plate suture zone, which is studded with numerous different sizes of fragments of micro-continental crust consisting of pre-Sinian metamorphic rocks and the North Qilian orogenic belt provides important study carrier for studying the pre-orogenic tectonic process of the North Qilian. The relatively complete volcanic-clastic-carbonate rocks formation of Zhulongguan Group, Changchengian System, Mesoproterozoic are distributed in the Kawa-Qiqing area, Western North Qilian orogenic belt. Geochemical characteristics of the Aoyougou Group basalts in the North Qilian indicated that the contents of major element were relatively stable, high K2O contents(4.27%~6.07%), TFe2O3(10.49%~13.01%),TiO2(1.96%~2.90%)and middle MgO(5.37%~6.71%,Mg# 48~51), CaO(2.57%~5.51%)content. Thus, the Aoyougou Group basalts belong to potassium alkaline basalt. The contents of Cr and Ni of the basalts decreased with the decreasing of Mg#, and there was a positive correlation between CaO and CaO/Al2O3, Furthermore, the Eu anomaly of samples was slightly negative, high contents of high field strength elements (HFSE, Nb, Ta, Ti), and the ratios of Gd/Yb(2.5~3.0), Zr/Y(8.6~10.2), Ta/Yb(0.96~1.23), Ti/Yb(5 074~6 021), Zr/Yb(81~97), Ce/Nb(1.87), Zr/Nb(6.41)indicated that the Aoyougou Group basalts had obvious OIB-type magmatic affinity. In combination with the regional geological background, the study results showed that Aoyougou Group alkaline basalt generated from deep enrichment mantle similar to the source of OIB, with fractional crystallization of olivine and monoclinic pyroxene and a certain degree of contamination of continental crust in the process of magmatism, formed in the background of continental rift, might response to the Proterozoic Columbia supercontinent rifting, which further provides important petrological evidences for the relationship between North China Craton rifting events and Columbia supercontinent rifting during Proterozoic.  相似文献   
150.
冀东地区位于华北板块北缘燕山造山带东部,矿产资源丰富,是中国金矿的主要产地之一,尤其是热液型金矿。峪耳崖金矿床是冀东众多热液型金矿床的典型代表,金矿主体赋存于侏罗纪峪耳崖花岗岩体内,少部分赋存于侵入花岗岩体的侏罗纪闪长岩脉中。闪长岩脉元素地球化学分析显示:w(SiO2)为51.99%~61.88%、Mg#值为0.37~0.64,w(Na2O+K2O)为5.07%~8.89%,A/NK为1.37~2.26,A/CNK为0.73~0.96,属准铝质高钾钙碱性系列;富集轻稀土元素和大离子亲石元素Rb、Ba、K、Sr,亏损重稀土元素和高场强元素Nb、Ta、Ti。锆石原位Hf同位素测试表明,εHft)为负值,介于-16.5~-6.5之间。综合研究认为:峪耳崖金矿区侏罗纪闪长岩浆源于俯冲流体交代的富集岩石圈地幔,岩浆上侵过程中受到华北板块古老下地壳物质的有限混染;成矿期闪长岩浆为金成矿提供了部分物质来源;峪耳崖金矿区闪长岩脉形成于古太平洋板块向欧亚大陆俯冲的动力学背景。  相似文献   
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