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81.
在矿床储量计算过程中,矿石体重预测的准确与否将直接影响到资源储储量的可靠程度.对矿石体重的准确预测需要大量运算的统计问题,利用SPSS(Statistical Product and Service Solutions)的Regression模块,对所测定的矿石小体重与其矿石品位进行多元回归分析,快速、准确的构建了矿石体重与品位的数学模型,从而为储量计算提供了科学依据. 相似文献
82.
论胶西北河西金矿床成因及其动力学条件 总被引:6,自引:0,他引:6
胶东河西金矿床属于典型的蚀变岩型金矿床.金矿体赋存于玲珑黑云母花岗岩体内,并受北东向断裂构造带所控制.87Sr/86Sr的初始比值表明,玲珑黑云母花岗岩和郭家岭花岗闪长岩均为壳源深熔花岗岩.地质和同位素年代学资料表明,金成矿作用发生在早白垩世.据硫、氧同位素组成判断,河西金矿床的成矿作用可能与郭家岭花岗闪长岩的流体活动有关,其成矿温度以中温为主,成矿压力为(1*!200~1*!400)×105 Pa.河西金矿床的花岗岩、蚀变岩和矿石的稀土与微量元素分布模式明显相似,说明它们有着共同的成因,与壳熔花岗岩岩浆作用有关. 相似文献
83.
平和铜钟坑一带1:10000土壤测量圈定了锡、钼、铜、铅、锌等元素异常及5个锡矿化蚀变带。铜钟坑锡异常分布于晚侏罗世南园组第二段火山碎屑岩中,异常范围大,浓度较高。裂隙带发育,矿化贮存于裂隙带中,成矿条件好。 相似文献
84.
Dunxian She Jun Xia Longteng Zhu Junmei Lü Xiangdong Chen Liping Zhang Xiang Zhang 《Stochastic Environmental Research and Risk Assessment (SERRA)》2016,30(4):1099-1113
This study investigates the changes of rainfall patterns along with the underlying reasons in the Nansi Lake Basin (NLB), China during 1960–2009. Results show that the annual rainfall increases from the northwest to the southeast of the NLB. From the temporal variation perspective, annual rainfall decreases slightly in the majority of stations. Furthermore, in spite of no pronounced trends are detected in all stations, the annual rainfall series fluctuate intensely, and present step changes around the year of 1974 and 2002. This change pattern of rainfall is verified by the approximately wet–dry–wet phase pattern, which is exhibited in the standardized departures of annual rainfall series, during the three sub-periods divided by the pre-obtained two change years. In particular, the parametric t test demonstrate that the step change in 2002 is significant. The variations in the rainy season (RS, June–September) rainfall contributed mostly to the changes in the annual rainfall, and a high similarity of change patterns between the RS and annual rainfall is also observed. The long term mean RS and annual rainfall decreases largely from the sub-period of 1960–1974 to 1974–2002, and increased largely from the sub-period of 1974–2002 to 2002–2009 in the NLB. Besides, various elements, such as the summer East Asian summer monsoon and summer Pacific decadal oscillation, may together lead to the step changes in summer rainfall over our study area. 相似文献
85.
86.
本文用CNDO/2法研究了硅碳双键Si=C不稳定的原因。通过分析SiH_2CH_2的烷基和苯基取代物的计算结果,对有大基因连接硅碳双键的化合物之所以能稳定存在做了合理的说明。 相似文献
87.
88.
Rendering 2D Lines on 3D Terrain Model with Optimization in Visual Quality and Running Performance
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Jiangfeng She Xin Tan Xingchen Guo Junzhong Tan Jianlong Liu 《Transactions in GIS》2017,21(1):169-185
With the gradual shift from 2D maps to a 3D virtual environment, various visual artifacts were generated by overlaying 2D map symbols on 3D terrain models. This work proposes a novel screen‐based method for rendering 2D vector lines with the accuracy of more than one pixel on the screen in real time. First, screen pixels are inversely projected onto a 3D terrain surface, and then onto the 2D vector plane. Next, these pixels are classified into three categories in terms of their intersection situation with the 2D lines. After that, a multiple sampling process is applied to the pixels that intersect with the 2D lines in order to eliminate visual artifacts, such as intermittence and aliasing (in pixel scale). Finally, a suitable point‐in‐polygon judgment is implemented to color each sample point quickly. The algorithm is realized in a heterogeneously parallel model so that the performance is improved and becomes acceptable. 相似文献
89.
A new, high-resolution and high-precision geoid has been computed for the whole of Canada and part of the U.S., ranging from 35°N to about 90°N in latitude and 210°E to 320°E in longitude. The OSU91A geopotential model complete to degree and order 360 was combined with a 5 × 5 mean gravity anomaly grid and 1km × 1km topographical information to generate the geoid file. The remove-restore technique was adopted for the computation of terrain effects by Helmert's condensation reduction. The contribution of the local gravity data to the geoid was computed strictly by the 1D-FFT technique, which allows for the evaluation of the discrete spherical Stokes integral without any approximation, parallel by parallel. The indirect effects of up to second order were considered. The internal precision of the geoid, i.e. the contribution of the gravity data and the model coefficients noise, was also evaluated through error propagation by FFT. In a relative sense, these errors seem to agree quite well with the external errors and show clearly the weak areas of the geoid which are mostly due to insufficient gravity data coverage. Comparison of the gravimetric geoid with the GPS/levelling-derived geoidal heights of eight local GPS networks with a total of about 900 stations shows that the absolute agreement with respect to the GPS/levelling datum is generally better than 10 cm RMS and the relative agreement ranges, in most cases, from 4 to 1 ppm over short distances of about 20 to 100km, 1 to 0.5 ppm over distances of about 100 to 200 km, and 0.5 to 0.1 ppm for baselines of 200 to over 1000 km. Other existing geoids, such as UNB90, GEOID90 and GSD91, were also included in the comparison, showing that the new geoid achieves the best agreement with the GPS/levelling data.Presented at theIAG General Meeting, Beijing, P.R. China, Aug. 6–13, 1993 相似文献
90.
本文以青岛城市环境地理信息系统为例 ,利用 GIS技术论述了地理信息系统在环境管理中的应用 ,对系统软件的设计与实现作了介绍和分析 ,着重论述了系统的技术关键和解决方案。说明了利用 GIS技术给环境管理工作带来的便利 ,及对环境地理信息系统的发展前景作了展望。 相似文献