矿产资源预测的精度评价

针对目前矿产资源预测理论及技术方法多种多样,却没有明确的对其预测精度进行评价的现状,从预测精度的影响因素方面考虑,提出了一种定量评价预测精度的方法。并应用此法对陕西省潼关县Q8金矿脉西段隐伏矿三维预测进行精度评价,与矿床开采实践的结论一致,证明了该方法的有效性。对矿产资源预测精度进行评价,能够使预测结果科学有效地指导探矿工程,降低找矿成本,提高经济效益。     

A possible generation mechanism of the strong current over the northwestern shelf of the South China Sea

Continuous observation in late April 2005 on the northwestern shelf of the South China Sea reveals vigorous strong currents, the maximum velocity of which exceeds 3.8 m/s. The strong currents occurred around spring tide period, when the internal tide waves were also expected to be vigorous. Analysis shows that the major peaks of the current power spectrum are in low frequency band. Using a numerical method applied to the actual ocean stratification, we find that the amplitude profiles of the strong current are similar to that of the currents induced by some low-mode internal waves (at diurnal or semi-diurnal frequency). It indicates that the temporal and spatial features of strong currents were possibly induced by low frequency internal waves.     

First observation of Karlodinium veneficum from the East China Sea and the coastal waters of Germany

Harmful algal blooms often occurred in the East China Sea (ECS) and the German coastal waters of the North Sea but Karlodinium veneficum had not been taxonomically reported. Two strains of Karlodinium (LAMB090611 and LAMB010601) were isolated from the two areas in 2009. The morphological characteristics and molecular phylogeny of two strains are compared on the basis of observation of a light microscope, a scanning electron microscope (SEM), a laser scanning micro-scope (LSM) and an internal transcribed spacer (ITS) sequence data. The mean cell length of strain LAMB090611 is (14.2 ± 1.8) μm (range 11.1-18.7 μm) and mean width is (10.8 ± 1.5) μm (range 8.2- 14.7 μm). The mean cell length of strain LAMB010601 is (15.1 ± 1.2) μm (range 12.7-17.9 μm) and the mean width is (11.4 ± 1.1) μm (range 9.1-14.7 μm), respectively. The two strains are similar in morphological characteristics, including a straight apical groove, distinct ventral pore, sulcal extension, cingulum displacement, two or four irregular shaped chloroplasts within the cell and almost equal sized epicone and hypocone. The large and round nucleus is located at the center or at the hypocone of the cell. The sequence length of the ECS strain LAMB090611 and the German strain LAMB010601 is 640 and 646 bp, respectively. The GC content is 49%. The nucleotide similarity of the two strains is 98.1%. The sequence divergence is 0.003. Both strains are confirmed as Karlo-dinium veneficum (D. Ballantine) J. Larsen and this is the first taxonomic report from China and Germany coastal waters. The population dynamics of this toxic species in the ECS and German coastal waters needs to be investigated in the near future.     

吕宋海峡M2内潮生成与传播数值模拟研究

本文在z坐标海洋数值模式HAMSOM中引入了内潮黏性项(Internal-tide viscosity term),将之运用到吕宋海峡M2内潮的生成与传播过程的数值模拟研究。研究结果表明:(1)在250 m以浅,吕宋海峡产生的M2内潮振幅于温跃层处最大,岛坡附近的内潮明显强于别处,且最大振幅可达到40 m左右;(2)M2内潮的生成源主要集中在伊特巴亚岛西北、巴丹岛西南以及巴布延群岛西北的岛坡;(3)海峡产生的M2内潮向东西2个方向传播。巴丹岛以西的西向能量在吕宋海沟斜向下传播,在到达恒春海脊附近发生反射返回海面,到达海面后再次反射回海底,在此过程中,有高模态的内潮被激发,不同模态间有相消干涉的现象产生。西传的内潮能量分为2支进入南海,产生于巴布延群岛西北的能量分支直接向西南折转进入南海海盆,而产生于伊特巴亚岛和巴丹岛岛坡附近的主要能量则以束状向南海陆架传播,在到达118°E后部分能量折向西南的海盆,其余的能量则沿西北方向传入中国近岸,陆架陆坡地形起着重要的耗散作用。伊特巴亚岛西北有最大的能量产生,向东北传入太平洋。在122°E以东,能量主要以束状向东南传入太平洋。     

村域经济分异的内在机制研究

村域是实现可持续发展的重要基地,是落实国家政策的理想试验田,是统筹城乡发展的有效途径。纵观不同村域经济发展型式,发现目前村域经济发展类型呈现出多样化、个性化(特色化)的发展特征,即使在相同的体制环境下,拥有同样的自然资源和相似的地理区位,村域经济实力及发展轨迹亦悬殊较大,经济发展类型有时会截然不同。研究认为,制度环境、自然资源开发、资本运作、市场带动、技术进步等,以及其间的非线性联系对村域经济发展型式的形成起着重要作用。     

单基站CORS系统在胜利油区石油天然气井位测量中的应用

随着GPS技术的飞速前进,利用网络RTK技术建立的连续运行卫星定位系统已成为GPS应用的发展热点之一。通过对胜利油田单基站CORS系统的组成、功能及在胜利油区石油天然气井位测量中的应用方式及精度分析的论述,对单基站CORS系统在石油天然气井位测量中的现实意义和应用前景进行了展望。     

我国GPS大地高的精度分析

分析了利用ＧＰＳ测定大地高的误差来源和提高其精度的措施。简介我国高精度ＧＰＳ中Ａ、Ｂ级网和各类区域网的布测和数据处理要点。根据误差传播理论和我国各级ＧＰＳ网实测误差，首次论证得出在我国任何地区ＧＰＳ大地高的绝对精度均可达到±０．１００ｍ的结论     

三种坐标间转换的雅可比矩阵数值导数计算方法

提出了一种用于空间大地直角坐标、大地坐标以及平面坐标与大地高之间相互转换的雅可比矩阵的数值导数的计算方法。该方法可以用较容易且精确的替代直接方法来实现不同类型间的坐标转换。在空间大地直角坐标与平面坐标与大地高之间的转换实验测试过程中，只要选取合适的增量，数值导数的精度都会满足要求，并且数值导数的精度的一致性也得到了验证。另外，该方法比采用直接方法计算速度显著加快，数值导数的精度、一致性和减少计算耗时在实验测试中效果非常好。     

Gradient plasticity modelling of strain localization in granular materials

The flow stress in the yield surface of plastic constitutive equation is modified with a higher order gradient term of the effective plastic strain to model the effect of inhomogeneous deformation in granular materials. The gradient constitutive model has been incorporated into the finite element code ABAQUS and used to simulate biaxial shear tests on dry sand. It is shown that the shape of the post-peak segment of the load displacement curve predicted by the numerical analysis is dependent on the mesh size when gradient term is not used. Use of an appropriate gradient coefficient is shown to correct this and predict a unique shape of the load displacement curve regardless of the mesh size. The gradient coefficient required turns out to be approximately inversely proportional to the mesh elemental area. Use of the strain gradient term is found to diffuse the concentration of plastic strains within shear band resulting in its consistent width. The coefficient of the higher gradient term appears as a function of the grain size, the mean confining stress, and the plastic softening modulus. Copyright © 2004 John Wiley & Sons, Ltd.