有机农药六六六对胶州湾海域水质的影响Ⅰ.含量的年份变化

根据1979～1984年(缺少1980年)的胶州湾水域调查资料,分析有机农药六六六(HCH)在胶州湾水域的含量大小、年份变化和季节变化。研究结果表明:在1979～1984年(缺1980年)期间,在胶州湾水体中HCH的含量逐年都在减少。在1983年,中国禁止HCH的使用,在禁用后,水体中HCH的含量全部低于一类海水的水质标准。在禁用后,水体中HCH的含量很低,几乎没有季节变化。因此,中国禁止HCH的使用对环境的改善取得显著的成效。     

冰川下垫面对夏季云结构和云水含量的影响——以祁连山区疏勒南山为例

云水含量和云结构参量是天气预报、高山区水循环过程分析的基础.基于2012—2015年夏季CloudSat卫星遥感资料的2B-CLDCLASS、2B-GEOPROF和2B-GEOPROF-LIDAR,结合中国第二次冰川编目数据及气象资料,对祁连山地区疏勒南山冰川区与非冰川区云水含量和云类型特征进行分析.结果 表明:(1)...     

Long‐term effects of revegetation on soil hydrological processes in vegetation‐stabilized desert ecosystems

Planting of sand‐binding vegetation in the Shapotou region on the southeastern edge of the Tengger Desert began in 1956. The revegetation programme successfully stabilized formerly mobile dunes in northern China, permitting the operation of the Baotou‐Lanzhou railway. Long‐term monitoring has shown that the revegetation programme produced various ecological changes, including the formation of biological soil crusts (BSCs). To gain insight into the role of BSCs in both past ecological change and current ecological evolution at the revegetation sites, we used field measurements and HYDRUS‐1D model simulations to investigate the effects of BSCs on soil hydrological processes at revegetated sites planted in 1956 and 1964 and at an unplanted mobile dune site. The results demonstrate that the formation of BSCs has altered patterns of soil water storage, increasing the moisture content near the surface (0–5 cm) while decreasing the moisture content in deeper layers (5–120 cm). Soil evaporation at BSC sites is elevated relative to unplanted sites during periods when canopy coverage is low. Rainfall infiltration was not affected by BSCs during the very dry period that was studied (30 April to 30 September 2005); during periods with higher rainfall intensity, differences in infiltration may be expected due to runoff at BSC sites. The simulated changes in soil moisture storage and hydrological processes are consistent with ongoing plant community succession at the revegetated sites, from deep‐rooted shrubs to more shallow‐rooted herbaceous species. Copyright © 2009 John Wiley & Sons, Ltd.     

Radon in soil anomaly observed at Los Azufres geothermal field,Michoacan: a possible precursor of the 1985 Mexico earthquake (Ms = 8.1)

A radon anomaly in a nuclear track detector placed on a fault was detected prior to the destructive (Ms = 8.1) Mexican earthquake of 19 September 1985. The fault is a structural feature of the geothermal field Los Azufres, 260 km NE of the epicentral area. Since no other phenomenon can be found as a possible cause for the radon anomaly, it is proposed that preseismic regional stress perturbations may produce changes in the fluid transport patterns at the fault, suggesting that radon measurements in similar conditions could provide a good precursor in high seismic risk areas.     

川西南干热河谷赤按人工林生物量和营养元素含量

用林木生物量回归方程，求得川西南干热河谷五年生赤桉纯林中乔木层生物量１３１３３．９ｋｇ／ｈａ（年平均生长量８０７９．７ｋｇ／ｈａ），草本层生物量５５２．０ｋｇ／ｈａ（枯落物现存量５９１．６ｋｇ／ｈａ）；赤桉与山毛豆混交林林分生物量２７１８６．９ｋｇ／ｈａ，其中赤桉生物量１６４９４．３ｋｇ／ｈａ（年平均生长量６６２０．２ｋｇ／ｈａ），灌木层生物量１０３６３．６ｋｇ／ｈａ，草本层生物量３２９．０ｋｇ／ｈａ（枯落物现存量１２６４．３ｋｇ／ｈａ）．混交林中赤桉生长好于纯林中赤桉的生长。林分营养元素含量不同植物差别很大，同种植物各器官也有所差别．各器官中营养元素含量顺序一般为：ｃａ＞Ｎ＞Ｍｇ＞Ｋ＞Ｐ，Ｐ是林地土壤缺乏的元素。     

岩石颗粒解离试验研究

试验确定，在用HCI和NaOH试剂解离硅质胶结的沉积岩时，浓度5％的试剂即可达到解离度95％以上，且颗粒表面特征、重矿物数量和重矿物标型特征较浓度10％的试剂处理的样品保存得更好。     

Some engineering characteristics of a compacted lateritic residual soil

Summary In many parts of the world, particularly in humid tropical regions, residual soils are abundant. In this paper the suitability of a residual lateritic soil as a construction material is investigated, with respect to its strength and compaction characteristics. In comparison with other typical construction fills available in Southeast Asia, compacted lateritic soils produce excellent shear strengths and CBR values. However, the brittleness and tensile cracking of this compacted material become enhanced on the dry side of the optimum moisture content, or if excessive compaction is imparted. Nevertheless, at a moisture content of 2% wetter than the optimum, the tensile mode of failure is suppressed and the lateritic fills become ideally suited for the construction of high embankments and impervious dam cores.     

高岭石的结晶有序度及其对纸张涂布粘浓度的影响

粘浓度是纸张涂布的一项重要指标,测定的变化范围从46.4—72％。用Hinckley方法测定了高岭石的结晶度指数,从0.57变化至1.40。当粘浓度>67％时,结晶度指数>1。粘浓度<67％,结晶度指数<1,有序高岭石有利于粘浓度提高。随着结构无序化,晶粒变小,晶片变薄,比表面增加,晶体边缘和角易破损,使粘浓度降低。结构无序化破坏了颗粒的均匀性,使颗粒长/厚比增加,粘浓度降低。高岭石八面体中Fe~(3+)的存在一定程度上影响了有序度。     

Sediment yield estimated from reservoir siltation in the Ochil hills,Scotland

Measurements made on the floors of the temporarily-drained Glenfarg and Glenquey Reservoirs indicate that sediments with wet volumes of 63.94 × 10³ m³ and 12.64 × 10³ m³ were deposited in 56 and 73 years respectively. These figures represent 2.5 per cent and 1.1 per cent losses of original storage capacity. When corrected for water, organic, and diatom skeleton contents, and reservoir trap efficiency inorganic sediment yields of at least 31.3 tonnes km^?2 yr^?1 and of 9.0 tonnes km^?2 yr^?1 are suggested. The difference is probably related to contrasts of land use.