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921.
元数据是关于数据的数据,目前被越来越多的应用于系统建设过程中。利用元数据,可以记录整个系统中数据的来龙去脉,这样可以把整个业务的工作流、信息流有效地管理起来,提高系统的可扩展性;此外元数据还具有数据发现和数据搜索的功能,能够提高系统的灵活性。介绍了国家级气象资料存储检索系统(MDSS)中实时气象数据库设计的元数据种类及其存储管理方式,以及元数据技术在实时气象数据库系统建设中的应用,详细描述了如何通过元数据提高软件的灵活性、可维护性。 相似文献
922.
923.
924.
Jun-Liang Zhao Li Chen 《中国天文和天体物理学报》2007,7(4):572-578
On the reasonable hypothesis that the internal motions of member stars of a cluster are random and isotropic, a method which can be used to estimate the velocity distance of the cluster and its uncertainty is developed. The velocity distance so determined is an absolute distance estimate, and is completely independent of the (widely used) luminosity distance, which is a relative distance estimate. Using the published high-accuracy observational data of radial velocities and proper motions of the stars in the open cluster M11 region, we have determined the distance of M11 to be 1.89 ± 0.52kpc. This is in quite good agreement with the published luminosity distances of the cluster. We briefly discuss the problems concerned, including the sources of errors in the method and its applicable range. 相似文献
925.
926.
The Anqing Fe–Cu skarn deposit, with an age of 134 to 142 Ma and resources of 62.4 Mt at 0.906% Cu and 32.2% Fe, is one of the most important deposits in the Yangtze River Metallogenic Belt, East China. To better understand the localization of orebodies and thus facilitate predictive exploration of deep orebodies, computational modeling is used to simulate the coupled geodynamic processes during the syn-tectonic cooling of the ore-related intrusion, based on geological and geophysical investigations in the Anqing orefield.The occurrences of the ore veins and veinlets in diorite and skarn, as well as the sharp zigzag boundary of the orebody, indicate that the Cu ores were deposited after the solidification of the diorite and skarn formation, and were located in some tensional structural spaces that are unevenly distributed along the contact zone between the felsic intrusion and sedimentary carbonates. The locations of orebodies are closely associated with the contact zone shape. The computational results of two models with two typical contact-shapes show that pore fluid flow was focused into the dilation zones from different sources. All the significant dilation zones, in which the existing orebodies were located, are distributed in some specific places of the south contact zone of the intrusion. In addition, these dilation zones are closely related to the contact zone shape of the intrusion and can control the location of orebodies through the coupled mechano-thermo-hydrological processes during cooling of the intrusion in the extension setting. The skarns are not critical for controlling the localization of orebodies. This means that exploration for deep ore should target deep dilation zones close to the contact boundary of the intrusion. Such recognition may provide a useful guide in selecting exploration targets in the Anqing orefield. As a direct result of computational modeling, an orebody has been discovered in the deep dilation zone in this orefield. It demonstrates that computational modeling is a promising tool for understanding the metallogenic processes and for facilitating the deep exploration of hidden orebodies that are related to intrusions. 相似文献
927.
Hu Yi-li Xu Jun Duan Yong-kong Xu Zhao-yong Yang Run-hai Zhao Jin-ming 《地震学报(英文版)》2004,17(6):725-734
A new method of detecting the vertical bearing capacity for single-pile with high strain is discussed in this paper. A heavy
hammer or a small type of rocket is used to strike the pile top and the detectors are used to record vibration graphs. An
expression of higher degree of strain (deformation force) is introduced. It is testified theoretically that the displacement,
velocity and acceleration cannot be obtained by simple integral acceleration and differential velocity when long displacement
and high strain exist, namely when the pile phase generates a whole slip relative to the soil body. That is to say that there
are non-linear relations between them. It is educed accordingly that the force P and displacement S are calculated from the amplitude of wave train and (dynamic) P-S curve is drew so as to determine the yield points. Further, a method of determining the vertical bearing capacity for single-pile
is discussed. A static load test is utilized to check the result of dynamic test and determine the correlative constants of
dynamic-static P(Q)-S curve.
Foundation item: Key projects of the tenth Five-year Plan of Yunnan Province (documented Yunnan district [2002]54-02-02) and Geophysical
Society of Yunnan Province. 相似文献
928.
南美厄瓜多尔Oriente盆地斜坡带发育的白垩系Napo组高伽马特征的UT海绿石砂岩段是成熟探区新发现的隐蔽含油层段。本文分析了海绿石砂岩储层的矿物组成、孔隙结构、成岩作用、物性特点,并结合烃源岩评价与石油空间分布探讨海绿石砂岩油藏的成藏特征。海绿石粘土矿物以颗粒形式存在,与石英共同构成海绿石砂岩的颗粒组分,海绿石砂岩的孔隙结构具有双峰特征,束缚水含量高,属于中-低孔、中-低渗储层类型,孔隙类型主要是剩余粒间孔。海绿石砂岩储层中石英次生加大属Ⅱ级,长石碎屑颗粒发生溶蚀作用,含铁碳酸盐类胶结物发育,结合泥岩低的I/S混层比和高的最高峰温值Tmax,指示海绿石砂岩层段属于中成岩阶段A期的产物。与海绿石砂岩油藏紧邻的大面积分布的Ⅱ1腐泥型成熟烃源岩就是缓翼斜坡带的生烃中心,大面积连续发育的海绿石砂岩与之构成优越的源储组合,有利于上生下储式成藏。海绿石砂岩油藏表现为近源性、成藏晚期性等特点,规模发育的海绿石砂岩储层得以成藏的主要运聚机制是体积流和扩散流运聚机制。这对盆地其它油区同类油藏的发现具有重要的借鉴意义。 相似文献
929.
Anzhou Zhao 《Arabian Journal of Geosciences》2016,9(15):664
Hydrological process modeling depends on the soil data spatial resolution of the watershed. Especially, in a large-scale watershed, could a higher resolution of soil data contribute to a more accurate result? In this study, two soil datasets with different classification systems FAO (World Reference Base) and GSCC (the Genetic Soil Classification of China) were used as inputs for the SWAT model to study the effects of soil datasets on hydrological process modeling in Weihe River basin, China. Results show that the discharge simulated using FAO soil data was better than one simulated using GSCC soil data before model calibration, which indicates that FAO soil data needed less effort to calibrate. After model calibration, discharges were simulated better by both of FAO and GSCC soil data but statistical parameters demonstrate that we can make a relatively more accurate estimation of discharge using the GSCC rather than FAO soil data. Soil water content (SW) simulated using GSCC soil data was statistically significantly higher than those simulated using FAO soil data. However, variations in other hydrological components (surface runoff (SURQ), actual evapotranspiration (ET), and water yield (WYLD) were not statistically significant. This might be because SW is more sensitive to soil properties. For studies aiming to simulate or compare SW, merely calibrating and validating models using river discharge observations is not enough. The hydrological modelers need to identify the key hydrological components intrinsic to their study and weigh the advantages and disadvantages before selecting suitable soil data. 相似文献
930.
本文研究的达茂旗黄合少、察哈尔右后旗古城和河北尚义县八道沟岩体位于华北克拉通北缘阴山—燕山北麓,索伦缝合带以南,沿近东西方向展布。主要岩石类型为正长岩、二长岩和石英二长岩。岩石地球化学研究表明其SiO2含量59. 08%~66. 52%, Al2O3= 15. 34%~21. 67%,A/CNK<1。属于准铝质中性岩范畴。全碱含量(Na2O+K2O)均在8%以上,在岩石的碱度率AR—SiO2图解上大多数样品落入碱性与过碱性区域,里特曼指数σ值从3. 73~10. 83均位于碱性或过碱性系列,属于碱性岩。岩体的微量元素以富集大离子亲石元素(LILE)如Rb、Ba和Sr等,亏损高场强元素(HFSE)如Ti、P、Nb和Ta等为特征。岩石稀土元素特征显示富集轻稀土元素(LREE),亏损重稀土元素(HREE)并且轻重稀土元素分馏比较明显的特征。除极个别样品外,岩石具有Eu负异常(δEu= 0. 35~0. 91)。通过对察哈尔右后旗古城正长岩体和河北尚义县八道沟富碱侵入岩体的高精度测年研究,获得其SHRIMP锆石U- Pb年龄分别为413. 2±3. 3~415. 0±5. 9 Ma和366. 8±5. 2~372. 3±4. 7 Ma,表明其均为古生代泥盆纪富碱侵入岩浆活动的产物。结合前人关于阴山—燕山北麓其它富碱侵入岩体(内蒙古固阳东高家村碱性正长岩体、黄合少碱性正长岩和冀北水泉沟碱性杂岩体 )的研究成果,推断在华北克拉通北缘阴山—燕山北麓一带,可能存在一条东西方向展布的晚古生代泥盆纪富碱侵入岩带。根据该岩带岩石地球化学特征,以及Ta/Yb—Th/Yb与Zr/Nb—Zr/Nb—Y/Nb判别图推测其岩浆物质来源可能与富集地幔有关,按照成岩温压环境指示,其形成深度位置约为下地壳,岩浆上升侵位过程中明显受到地壳物质的混染。依据前人关于碱性岩特征的研究,结合本文研究岩体的岩石化学特征和及Rb—Nb+Y构造判别图解指示,推测岩体形成于张性构造环境,可能与古生代志留纪末兴蒙造山带南部发育的白乃庙岛弧带和华北克拉通发生弧—陆碰撞后的伸展背景相关。 相似文献