Distribution and Variation of Ribonucleic Acid （RNA） and Protein and Its Hydrolysis Products in Lake Sediments

Protein and RNA in lake sediments tend to be decomposed progressively with time and sedimentation depth. Their concentrations tend to decrease starting from the sedimentation depth of 17 cm and that of 19 cm, respectively. However, the products of their decomposition —amino acids and nucleotides show different rules of variation. At the depth from 27 cm to 30 cm the amino acids are most abundant in the pore waters of lake sediments. Such variation tendency seems to be related to the extent to which microbes utilize amino acids and nucleotides. Due to polymerization in the geological processes and the adsorption of protein on minerals and organic polymers, below the sedimentation depth of 17 cm there is still a certain amount of protein in the sediments. With the time passing by, protein has been well preserved in various sediment layers, indicating that its decomposition is relatively limited. The peak values of protein content in the sediments of the two lakes are produced in the surface layers at the depth of 10 cm, implicating that the surface sediments are favorable to the release of protein. The contents of amino acids in the pore waters of lake sediments are closely related to the activities of microbes. Below the depth of 27 cm, the amino acids are significantly accumulated in Lake Aha sediments, probably indicating the weakening of microbial activities. The research project was financially supported jointly by the Ntional Natural Science Foundation of China (No. 40173038) and the Guizhou Provincial Foundation (No. 3090) and the Chinese Academy of Sciences Knowledge-Innovation Foundation (KZCX2-105).     

Geochemical evolution of highly alkaline and saline tank waste plumes during seepage through vadose zone sediments

Leakage of highly saline and alkaline radioactive waste from storage tanks into underlying sediments is a serious environmental problem at the Hanford Site in Washington State. This study focuses on geochemical evolution of tank waste plumes resulting from interactions between the waste solution and sediment. A synthetic tank waste solution was infused into unsaturated Hanford sediment columns (0.2, 0.6, and 2 m) maintained at 70°C to simulate the field contamination process. Spatially and temporally resolved geochemical profiles of the waste plume were obtained. Thorough OH⁻ neutralization (from an initial pH 14 down to 6.3) was observed. Three broad zones of pore solutions were identified to categorize the dominant geochemical reactions: the silicate dissolution zone (pH > 10), pH-neutralized zone (pH 10 to 6.5), and displaced native sediment pore water (pH 6.5 to 8). Elevated concentrations of Si, Fe, and K in plume fluids and their depleted concentrations in plume sediments reflected dissolution of primary minerals within the silicate dissolution zone. The very high Na concentrations in the waste solution resulted in rapid and complete cation exchange, reflected in high concentrations of Ca and Mg at the plume front. The plume-sediment profiles also showed deposition of hydrated solids and carbonates. Fair correspondence was obtained between these results and analyses of field borehole samples from a waste plume at the Hanford Site. Results of this study provide a well-defined framework for understanding waste plumes in the more complex field setting and for understanding geochemical factors controlling transport of contaminant species carried in waste solutions that leaked from single-shell storage tanks in the past.     

开滦煤矿岩溶陷落柱的发育特征及规律研究

根 据 煤 矿 井下 生 产 揭 露陷 落 柱 的 实践 经 验 ,对 矿 区 内 岩 溶 陷 落 柱 的 发 育 特 征 、形 成 条 件 和 发 育 规 律 ,充 水 类型 和透 水 性,陷落 柱出 现 的前 预兆 等 几方 面谈 了 自己 的认 识 。     

Silicon isotope abundance ratios and atomic weights of NBS-28 and other reference materials

The silicon isotope abundance ratios and atomic weights of NBS-28 and several other silicon isotope reference materials were determined in this study. For the calibration of the measurement procedure, two new synthetic isotope mixtures were prepared gravimetrically from highly enriched silicon isotope materials in the form of SiO₂. All materials were converted into SiF₄ gas and subsequently their silicon isotope ratios were measured on the SiF₃⁺ species by using a gas source mass spectrometer MAT-253. The calibrated isotope abundance ratios of NBS-28 are 0.0507446 (26) for ²⁹Si/²⁸Si and 0.0341465 (15) for ³⁰Si/²⁸Si. The corresponding isotopic abundances are 92.17515(28)% for f(²⁸Si), 4.67739(24)% for f(²⁹Si) and 3.14746(14)% for f(³⁰Si). The silicon molar mass of NBS-28 is determined to be 28.08653(11), which is 0.001 larger than previously reported values. In the meanwhile, the ²⁹Si/²⁸Si and ³⁰Si/²⁸Si isotope abundance ratios and atomic weights of SRM-990, IRMM-017, IRMM-018, GBW-04421 and GBW-04422 are also calibrated. These new calibrated data can improve the reliability and comparability of silicon isotope results using above calibrators.     

Spatial damage distribution of August 16, 2003, Inner Mongolia, China, M S=5.9 earthquake and analysis

The spatial damage distribution of August 16, 2003, Inner Mongolia, China, M _S=5.9 earthquake is summarized through field investigation. The moment tensor solution and focal mechanism are inverted using the digital long-period waveform records of China Digital Seismograph Network (CDSN). The relation between the spatial damage distribution and focal mechanism is analyzed according to the focal mechanism, the aftershock distribution and the spatial damage distribution. The possible relation between the characteristics of ground motion and the tectonic background of the source region is discussed in terms of the global ground motion records, historical earthquake documents and the damage distribution. Investigation reveals that the meizoseismal region is in east-west direction, which is consistent with the nodal plane of focal mechanism inversion. The meizoseismal area is relatively large and the damage of single-story adobe houses or masonry houses is more severe. This may have relations with local seismotectonic environment. Foundation item: The Special Funds for Major State Basic Research Project (2002CB412706). Contribution No. 05FE3009, Institute of Geophysics, China Earthquake Administration.     

武汉新一代天气雷达CINRAD／SA的环境技术要素分析

介绍了武汉CINRAD／SA雷达系统建设中确定雷达塔高与频点的技术分析过程，明确提出了雷达站四周的净空保护要求；重点计算和分析了CINRAD／SA雷达在3种实际运行模式(vCPll、VCP21、VCP31)下电磁辐射功率密度的空间分布，并按照国家“电磁辐射防护规定”和“电磁辐射环境影响评价方法和标准’’的要求，估算了武汉CINRAD／SA雷达电磁辐射的最小防护距离。     

南方层积混合云催化作业与数值模拟

利用一维套柱模式对层积混合云进行了模拟实验，并以１９９５年夏季在鄂西北上空６次飞机增雨作业为例，对积云催化的效果做了定性验证。通过探讨云的催化机制，探求有效的催化技术方法，将实际作业、自然模拟、催化模拟进行了对比。     

论构造事件的节律性

构造事件是否存在节律性，长期以来一直存在着不同的意见。根据国内外最新研究结果，笔者认为构造事件、生物灾变事件、巨大陨击事件、气候与环境变化都能表现出一定程度的节律性、周期性或旋回性。在一些大陆边缘地区，构造作用表现出几千万年相对的稳定期和数百万年的活跃期（突变期）相间的演化过程，而在板块内部与造山带，节律性则可能表现得不太明显。岩石圈上各地区的构造活跃期，由于应力集中现象缓慢传递的结果，而表现出全球不同时的特征。看来，构造事件尽管都是流变作用的产物，但仍然具有节律性，不过各地区存在着不等时和不同时的节律性。     

基于GIS的洪水灾害评估智能决策支持系统设计

针对洪水灾害评估的特点，将地理信息系统（ＧＩＳ）技术与智能决策支持系统结合起来，设计了用于洪水灾害评估的智能决策支持系统，阐述了其设计原理，讨论和分析于基于ＧＩＳ的洪水灾害评估智能决策支持系统的组成模式，给出了其总体设计框架。     

Experimental study of silicon isotope dynamic fractionation and its application in geology

Silicon shows no variation in its chemical valence in nature and exists mainly in the form of silicon-oxygen tetrahedra, so very small silicon isotope thermodynamic fractionation occurs and the resultant silicon isotope variation is limited. Dynamic fractionation of Si isotopes during precipitation of SiO₂ from a solution is a main factor leading to substantial variations in silicon isotopes in nature. In this experimental study, we determined the dynamic fractionation factorα for silicon isotopes during precipitation of SiO₂ from the solution. And in combination of α, a theoretical explanation is presented of the considerably low δ³⁰Si values of black smokers on modern seafloor, Archean banded magnetite-quartzite and clay minerals of weathering origin, and of clearly high δ³⁰Si values of siliceous rocks in shallow-sea carbonate platforms. This paper won the Paper of Excellence in the Second National Young Scientist Symposium on Geochemistry of Minerals and Rocks.