湖南砂矿金刚石中顺磁氮的分配特点和金刚石归类问题

利用EPR检测了200多颗湖南砂矿金刚石。为53颗晶体测定了顺磁N的含量。阐明了砂矿金刚石中顺磁N分配的一般特点:具顺磁N信号者占30％,具较大顺磁N含量(10~(17)—10~(18)N原子/cm~3)者只占7％,属I_b型的晶体～2％。通过顺磋和红外光谱资料对比,发现了一些奇异现象,设想后者起因于混型晶的存在。为使金刚石正确归类,给出了一套测试方案,强调了紫外、红外光谱,紫外形貌照相和EPR等手段的联合使用。     

利用可提取性磷脂表征沉积物中微生物的生物量

应用ＧＣ－ＭＳ技术,分析了深圳大亚湾大鹏澳及厦门岛南岸海域沿岸几个站位沉积物中可提一磷脂酯结合态脂肪酸的含量和组成成份;同时采用吖啶橙荧光染色计数法测定了这些的中细菌的丰度、重担一。结果表明,在这些沉积物中细菌的生物量与磷脂酯结合态脂肪酸的组份的含量有着正相关关系。说明在环境生态研究中,可提取性磷脂作为海洋和河口沉积物中微生物生物量的生物标志物的可行性。     

金刚石微粉的技术标准

比较详细的分析了国外有关金刚石微粉的国家标准、厂家标准和行业标准，对国内厂家、用户及从事金刚石微粉研究和生产的人员有所用处。     

河北迁西县山区生态环境脆弱性分区初探

山区生态环境脆弱性划分可指导人类活动的方式和强度，对山区生态保护和资源合理利用具有重要意义。本文以河北省迁西县山区为例，论述了选取山区生态环境脆弱性影响因子的主要原则，探讨了脆弱性影响因子的分级与赋值量化，应用灰色关联度分析确定影响因子的权重。经过综合评判，把迁西县山区生态环境脆弱性分为强度脆弱和中度脆弱，再进一步细分为强2脆弱、强3脆弱、中1脆弱、中2脆弱和中3脆弱，并进行了脆弱区划分。针对各脆弱区的特点，文章提出了相应的资源利用和责无环境保护对策。     

鄂尔多斯盆地中东部奥陶系马家沟组马五6亚段硬石膏产状类型与成因*

鄂尔多斯盆地中东部奥陶系马家沟组马五₆亚段硬石膏产状类型多样,基于系统的宏观与微观岩石学分析,识别并区分出星散状(A1型)、纹层状(A2型)、致密块状(A3型)、结核状或团块状(A4型)、鸡雏状或角砾状(A5型)等硬石膏产状类型。单井高频旋回和微相分析表明,马五₆亚段发育与潮坪、潟湖、鲕粒滩、砂屑滩、微生物丘等有关的5种高频向上变浅序列,硬石膏的产状类型、产出位置和分布形式等与向上变浅序列有很好的耦合关系。A1型和A2型硬石膏发育于高频向上变浅序列的下部和中部,主要与膏云质或云膏质潟湖相关,属于潟湖相原生化学沉积成因。A3型硬石膏分布于高频向上变浅序列的上部,受膏质潟湖控制,也属于原生化学沉积成因。经典的结核状硬石膏(A4-1)呈随机分布形式产于潮坪沉积序列,为成岩期交代作用或者膏化作用成因,与传统萨布哈交代成因的膏质结核相似。A4-2型硬石膏主要出现在颗粒岩和微生物岩中,主要由富含CaSO₄的下渗卤水在溶蚀孔洞中沉淀形成;A5型硬石膏发育于向上变浅序列的上部和顶部,与高频暴露有关,为准同生期以溶蚀—充填为主的岩溶改造成因。发育完整的单个高频旋回,大致经历了高频快速海侵早期、高频快速海侵晚期至缓慢海退早期、高频缓慢海退晚期和高频海退末期暴露4个演化阶段,形成了与之耦合的海相碳酸盐岩与硬石膏共生序列。这些认识将对马家沟组沉积古环境的再认识具有重要的参考意义。     

Numerical modelling of time-harmonic seismic wave fields in simple structures by the gaussian beam method. part I

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Fast computation of ray synthetic seismograms in vertically inhomogeneous media

Summary A procedure of fast computation of body-wave ray synthetic seismograms in vertically inhomogeneous media is suggested. The procedure uses a special approximation of the velocitydepth distribution which guarantees continuity of the first and second derivatives of velocity and does not generate false low-velocity layers (oscillations in the velocity-depth function). The ZESY82 program package, which is based on the suggested procedure, is described. The point source with an arbitrary radiation pattern may be situated at any points of the model, the receivers are situated regularly or irregularly along any profile on the Earth's surface, containing the epicentre. Numerical examples of the synthetic record sections for a model of the Earth's crust and the uppermost mantle are given.

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Sensitivity of seismic waves to structure

We study how the perturbations of a generally heterogeneous isotropic or anisotropic structure manifest themselves in the wavefield, and which perturbations can be detected within a limited aperture and a limited frequency band. A short-duration broad-band incident wavefield with a smooth frequency spectrum is considered. In-finitesimally small perturbations of elastic moduli and density are decomposed into Gabor functions. The wavefield scattered by the perturbations is then composed of waves scattered by the individual Gabor functions. The scattered waves are estimated using the first-order Born approximation with the paraxial ray approximation. For each incident wave, each Gabor function generates at most 5 scattered waves, propagating in specific directions and having specific polarisations. A Gabor function corresponding to a low wavenumber may generate a single broad-band unconverted wave scattered in forward or narrow-angle directions. A Gabor function corresponding to a high wavenumber usually generates 0 to 5 narrow-band Gaussian packets scattered in wide angles, but may also occasionally generate a narrow-band P to S or S to P converted Gaussian packet scattered in a forward direction, or a broad-band S to P (and even S to S in a strongly anisotropic background) converted wave scattered in wide angles. In this paper, we concentrate on the Gaussian packets caused by narrow-band scattering. For a particular source, each Gaussian packet scattered by a Gabor function at a given spatial location is sensitive to just a single linear combination of 22 values of the elastic moduli and density corresponding to the Gabor function. This information about the Gabor function is lost if the scattered wave does not fall into the aperture covered by the receivers and into the legible frequency band.     

Facies Architecture Model of the Shimentan Formation Pyroclastic Rocks in the Block‐T Units,Xihu Sag,East China Sea Basin,and its Exploration Significance

A gas field consisting of volcanic reservoir rocks was discovered in the block-T units of the Xihu Sag, East China Sea Basin. The lithology of the volcanic rocks is dominated by tuff and reworked tuff. The lithofacies are dominated by base surge deposits of explosive facies. As the architecture model of volcanic facies is still uncertain, it has restricted the exploration and development of mineral resources in this area. Using core and cuttings data, the lithology, lithofacies, geochemistry as well as grain size characteristics of volcanic rocks were analyzed. Based on these analyses, the volcanic rocks in the well section are divided into three eruptive stages. The transport direction of each volcanic eruption is analyzed using crystal fragment size analysis. The facies architecture of the block-T units was established based on the reconstruction results of paleo-geomorphology. The results show that the drilling reveals proximal facies (PF) and distal facies (DF) of the volcanic edifices. However, the crater-near crater facies (CNCF) are not revealed. Compared with the reservoirs of the Songliao Basin, it is shown that the volcanic rocks in the Xihu Sag have good exploration potential; a favorable target area is the CNCF near the contemporaneous fault.     

Remote sensing mapping of the regeneration of coastal natural habitats in Singapore: Implications for marine conservation in tropical cities

Rapid urbanization has resulted in the loss of coastal and marine habitats in cities worldwide. The effective conservation of urban coastal ecosystems requires detailed knowledge of their spatial distribution, necessitating high-resolution mapping. Our study produces a high-resolution coastal and marine habitat map and shoreline map for the tropical city-state of Singapore created through pixel-based supervised classification of satellite imagery, bathymetry data and expert ground knowledge. These maps can be used as a base reference for multiple applications including ecological research, conservation and urban planning. They also help identifiy trends in the extent of key coastal habitats, providing insight into their differing levels of vulnerability to loss and potential for restoration to ensure long-term resilience. The method used for mapping shoreline typologies and resulting insights gained, can guide other rapidly urbanizing coastal cities on strategies to assemble useful spatial knowledge for effective conservation of their urban coastal ecosystems.