土地整理中水资源评价及供需平衡分析——以济南市商河县郑路镇土地整理项目为例

水资源平衡分析是进行土地整理的前提和基础。在项目可行性研究中,只有摸清项目区的水资源量和可用水量,才能因地制宜对项目区进行科学规划。以济南市商河县郑路镇中低产田项目区为例,对水资源供需平衡进行了评价和分析,以求得水资源供需平衡,进而提高土地利用率。     

西藏尼洋河水环境特征多元统计分析

自2008年11月到2009年10月按照月份监测西藏林芝地区尼洋河水环境特征.结果显示,根据Pearson相关性矩阵,可将尼洋河26项理化指标分为3大类,分别是低度相关性理化指标、中度相关性理化指标和高度相关性理化因子.析因分析显示,可将26项理化指标分为4大类,第1类为尼洋河水体常规的理化指标、第2类为尼洋河水体硬度相关指标、第3类为海拔及第4类为影响水生生物生长的水质理化指标.PCA分析发现,平水期、丰水期以及枯水期水环境特征明显不同,以上3期各自聚为一类,而尼洋河沿程方面,水环境特征则不存在差异.构建了尼洋河海拔、底层水温与相关理化因子的一元回归方程.建议加强对尼洋河水环境的监测工作,积极推进尼洋河水域生态环境的可持续发展进程.     

Influence of environmental disturbances and reproductive strategy on genetic diversity and differentiation of Zostera marina populations on the southern coast of Korea

The genetic diversity and differentiation of four Zostera marina populations along the southern coast of Korea were estimated using random amplified polymorphic DNA (RAPD) markers to determine the effects of natural and anthropogenic stresses and reproductive strategy on within‐population genetic diversity. The mean number of alleles and gene diversities, indicating population genetic diversity, was highest in the Z. marina population that was exposed to repeated environmental disturbances, and lowest in the most undisturbed population. The higher genetic diversity in the disturbed population was associated with a higher contribution of sexual reproduction to population persistence. This suggests that both the level of disturbances and the reproductive strategy for population persistence contributed significantly to population genetic diversity at the study sites. According to the analysis of molecular variance (AMOVA), 76% genetic variation was attributable to differences among individuals within populations. The observed genetic differentiation (F_ST = 0.241) among Z. marina populations at the study sites appeared to result from reduced meadow size, increased genetic drift, and a high incidence of asexual reproduction. Increased population genetic diversity can enhance resistance and resilience to environmental disturbances; thus, this investigation of seagrass population genetics provides valuable new insights for the conservation, management, and restoration of seagrass habitats.     

Experimental investigation of three-dimensional earth pressure according to aspect ratio of retaining wall

The purpose of this study is to investigate the scale and load distribution of three-dimensional active earth pressure and the load transferred to the adjacent soil by changing the aspect ratio of a retaining wall through a series of model tests. In this research, 42 earth pressure plates of different heights and widths were installed to evaluate the earth pressures by considering the wall aspect ratio and the change of earth pressure. The test results showed that the active earth pressures were uniformly converged when the percentage of limit displacement against wall height was 0.12%. The distribution of active earth pressure on the wall showed a parabola shape for most aspect ratios while the wedge shape identified by the model test was similar to the shell-shaped model. In this paper, two diagrams were proposed regarding the active earth pressure according to the aspect ratio of a retaining wall; (1) a diagram of earth pressure conversion against the aspect ratio based on evaluated three-dimensional active earth pressures with traditional two-dimensional earth pressures, (2) a load transfer diagram based on the horizontal distance by analyzing the horizontal and vertical load transfer ranges with the relevant increasing rates.     

Energy correction of dynamic cone penetration index for reliable evaluation of shear strength in frozen sand–silt mixtures

Acta Geotechnica - Previously, in situ tests have been conducted in cold regions since infrastructures such as pipelines have been actively built on frozen ground. However, the engineering...     

K-Ar法地质年龄标准物质ZBJ角闪石的定值结果

为了满足K-Ar定年中K和⁴⁰Ar^*分析的质量监控及Ar-Ar法样品在反应堆照射时中子通量监测的需要,我国氩同位素年代学工作者研制了一个K-Ar法年龄标准物质ZBJ角闪石,它采自北京房山花岗闪长岩体。它的⁴⁰Ar-³⁹Ar阶段加热分析结果表明:⁴⁰Ar^*在矿物晶格中保存均匀稳定,年龄谱平坦,³⁹Ar析出量高达97%。这些证据充分表明该黑云母结晶以后未受过热扰动,40K-⁴⁰Ar^*同位素计时体系封闭良好。坪年龄为133.3±0.6Ma,总气体年龄为134.4±1.4Ma,³⁶Ar/⁴⁰Ar-³⁹Ar/⁴⁰Ar反等时线年龄为133.2±0.8Ma,⁴⁰Ar/³⁶Ar初始值为297.6±4.8,此值与(⁴⁰Ar/³⁶Ar)a大气氩丰度比(295.5±0.5)处于同一范围,表明样品不含过剩氩。这几个年龄值的一致性,说明该样品具有良好的均匀性和稳定性,它作为K-Ar和Ar-Ar法地质年龄标准物质是适合的。ZBJ角闪石均匀性检验结果表明:在0.05显著性水平下经统计学方法检验,证明K和⁴⁰Ar^*的F分布值小于F临界值,说明该样品是均匀的。国内8个实验室参加了ZBJ角闪石K含量和⁴⁰Ar^*含量的定值分析,经统计学方法检验,结果显示全部定值数据都服从正态分布并具等精度。在置信概率为0.95时,⁴⁰Ar*和K含量的相对标准偏差都小于1%。两个特性量值定值分析结果的一致值(认定值)和不确定度分别为:⁴⁰Ar^*=(2.464±0.018)×10^-10mol/g,K=(1.027±0.008)%,K-Ar年龄(标准值)=133.3±1.5Ma(2σ)。此标准物质纯度为98.1%,粒度为0.15～0.30mm,总重量为740g,缩分成最小样品单元共100瓶,每瓶7.4g,可供我国K-Ar和Ar-Ar法同位素年代学实验室使用37年。     

New radiometric dating of the dykes from the Hurd Peninsula, Livingston Island, South Shetland Islands

Fifteen new K–Ar ages in the range of 79–31 Ma are partially confirmed by three ⁴⁰Ar/³⁹Ar plateaus and isochron data of 64.9±0.4, 55.5±0.1 and 52.8±0.6 Ma. The new geochronological data reveal a much more detailed picture of the subduction imprint in the Hurd Peninsula. Using cutting relationships, the dyke emplacement history is divided into four episodes. The Late Cretaceous–Paleocene dykes in the range of 80–60 Ma are related to the main magmatism in Livingston Island and most likely reflect the final stages of subduction of the proto-Pacific oceanic crust. The Early Eocene dykes (56–52 Ma) fill the gap in volcanic activity 70–50 Ma ago. They are the only magmatic event manifested at this time in the region. The 45–42 Ma dykes may be related to the intrusion of the Barnard Point tonalite. Three samples of Oligocene age appear to represent the last igneous activities on the Hurd Peninsula prior to the opening of the Bransfield Strait.     

ARD generation and corrosion potential of exposed roadside rockmass at Boeun and Mujoo,South Korea

Acid rock drainage (ARD) is a longstanding problem often associated with the resulting corrosion due to the acidity generated from sulfidic oxidation. To evaluate characteristics of ARD and corrosion, samples from the road side rock mass of Boeun and Mujoo were analysed using X-ray diffraction, acid/base accounting and Leaching tests. The results indicated that many samples had a pyritic origin and can be regarded as acid-generating rocks. The Leaching test showed that the average pH of the leachates of samples from both Boeun and Mujoo were moderately acidic, ranging from 3 to 4. Interestingly, as acidity increases from pH 4, the SO₄₋, Fe, Al and Mg concentrations increase abnormally. Samples from roadside slope of Mujoo showed high corrosive potential. Maximum sulfide oxidation rate of a sample taken from Mujoo was as high as 5,166 mg/kg/week.     

煤储层吸附特征研究现状及展望

从吸附机理、吸附数学模型、吸附影响因素以及多元气体吸附等几个方面，综述了国内外煤储层吸附气体研究的现状，分析了当前我国煤储层吸附研究中存在的问题和难点，对下一步煤储层吸附研究的发展趋势和需要解决的问题作了进一步的探讨。