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621.
坡面植被对坡面径流和入渗的影响 总被引:7,自引:0,他引:7
通过人工模拟降雨和自然降雨试验,本文讨论了植被对雨水的截留和分流作用,以及坡面植被对水流入渗的影响。 相似文献
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Kinetic parameters for the epimerization of isoleucine in multispecific foraminiferal asemblages were used to establish the effects of burial depth and the geothermal gradient on the extent of reaction. It was observed that with a little as thirty meters of burial in a normal thermal regime there were differences between the extent of epimerization measured and that which would have been predicted for thermal equilibrium with bottom water temperatures. As would be expected, these differences are greatest when the heat flow (the geothermal gradient) and/or the sedimentation rates are highest. These effects were observed in most of the DSDP samples studied, and have been used to estimate the average heat flux since the time of sample deposition. Occasional anomalous effects were observed which could not be related to past or present heat flux. These were determined to be due to such geologic occurrences as slumping and reworking or to recent sample contamination. Other problems emerged related to bottom water temperatures including changes over geologic time which are unknown and could not be deduced. Thus, the presence of epimerization anomalies in DSDP cores as noted above limits the effectiveness of amino acid geochronology in such cores, unless these anomalies can be recognized as ab initio. 相似文献
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Kyoungsoon Shin Min-Chul Jang Pung-Kuk Jang Se-Jong Ju Tea-Kyun Lee Man Chang 《Progress in Oceanography》2003,57(3-4):265
Egg production, egg viability and fecal pellet production were determined for individual Acartia omorii, which were fed diets of two species of diatoms (Skeletonema costatum and Phaeodactylum tricornutum) and three species of dinoflagellates (Scrippsiella trochoidea, Heterocapsa triquetra and Cochlodinium polykrikoides). Diets were analyzed for fatty acid content as an indicator of food quality. Depending on the diet, egg production of A. omorii varied over time, diminishing with some diets (S. trochoidea, C. polykrikoides, P. tricornutum). This rate of reduction was much more rapid for a diet of C. polykrikoides, which caused egg production to decrease to ca. 2.4 eggs f−1 d−1 in only four days. As for all diets, egg viability was high at the beginning but with the C. polykrikoides and P. tricornutum diets, it rapidly decreased with time. Fecal pellet production also varied with time, depending on the diet. Egg production rate was closely correlated with fecal pellet production. There was no direct relationship between egg viability and egg production rate, but both egg production and viability were affected by the nutritional quality of food. Egg viability was also highly dependent on the composition of fatty acids in the eggs. Egg viability showed positive correlation with the ratio of ω3:ω6 groups among egg fatty acids, and negative correlation with the ratio of 20:5 (n−3) : 22:6 (n−3). While comparing several diets, egg production rate was higher on diets (H. triquetra and S. trochoidea) containing ample amounts of essential fatty acids such as 18:4 (n−3) and 22:6 (n−3). The results suggest that fertility of A. omorii was dependent upon the quality of the food, and dinoflagellate diets, with the exception of C. polykrikoides, were preferable to diatom diets. 相似文献
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We analyze the data of measurements of the indicatrices of scattering of light in the Black Sea in winter 1991 and summer 1998, present their principal characteristics, and discuss their correlations and spatial variability. The data on scattering of light are used to determine the number and weight concentrations of various fractions of particles suspended in water. The characteristics of scattering of light and the composition of suspension in the Black Sea are compared with the data obtained in 1973 and with the data accumulated in the Aegean and Ionian Seas and in the Indian Ocean.__________Translated from Morskoi Gidrofizicheskii Zhurnal, No. 1, pp. 63–76, January–February, 2005. 相似文献
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郯庐活断层与1668年郯城8.5级地震灾害 总被引:13,自引:0,他引:13
郯庐断裂带的地震活动主要集中于中部的下辽河-莱州湾段和潍坊-嘉山段,各段在活断层和地震活动方面存在不同的表现。1668年地震发生于潍坊-嘉山段的中部,是全新世断层活动的结果。该地震产生了性重的人口损失和建筑物破坏,其地震灾害具有典型性。未来应注意渤海地区地震的群集型活动以及安丘地区和新沂-泗洪地区的强震活动。还应注意在新的经济条件下新的地震灾害内容和新的灾害类型。 相似文献