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351.
????????????????д????????ò???????????????????????????ε??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????硢??????????????????Ч??????????????????????????????????????????С?? 相似文献
352.
局部型地形因子并行计算方法研究 总被引:2,自引:0,他引:2
随着分析区域的扩展及需求精度的提高,数据-计算密集型地形分析亟需通过并行化来满足用户的时间响应需求。局部型地形因子是以一定半径的分析窗口(通常为3×3)计算且具有单元计算结果独立性的地形信息,是数字地形分析的基本参数。本文在分析局部型地形因子串行算法特征的基础上,以坡度算法为样本,对局部型地形因子的并行计算方法进行了深入研究。从数据并行的角度,对并行计算环境下的数据划分粒度、方式及结果融合策略进行了分析,构建了局部型地形因子的并行计算方法。利用SRTM陆地表面地形DEM数据,设计了坡度并行计算的实验以验证其方法的正确性和实用性。实验结果表明,本文提出的并行计算方法顾及了任务、数据及计算环境,可快速对局部型地形因子串行算法进行并行化改造,提高算法的执行效率,具有较好的并行性能。 相似文献
353.
????????????????????????????????????BP???????????????????人???????????????????????????????????BP??????????????????г????????????????????????о??????????BP???????????????????????????????????????????????? 相似文献
354.
1INTRODUCTIONEcosystem services can be divided into two major cat-egories, one is system function, and the other is sys-tem services and goods provision, which provide not only materials such as food and medicine, but also support and maintenance of whole system. Ecological services contribute to the whole economic system, both directly and indirectly, and consequently repre-sent parts of the total value of our economy system (COSTANZA etal., 1997; GUO etal., 2001). Sustainable d… 相似文献
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??????????????????????????????????????С?????????????????????????С?????????????????????????????????????????????????????????????????????????????????Ч???? 相似文献
357.
An air-gun source is the most commonly used excitation method in offshore seismic exploration.The excitation characteristics of an air-gun source affect seismic... 相似文献
358.
In situ Microphytobenthic community dynamics were combined with laboratory measurement of predominant species by fluorescence methods to estimate the areal primary production. Field investigation of community dynamics of microphytobenthos (MPB) was conducted from August 2006 to August 2007 in intertidal flats of the Nakdong River estuary, Korea. MPB Biomass varied between 0.47 and 16.58 μg cm?3 in the surface 1 cm sediment, with two dominant diatom species, Amphora coffeaeformis and Navicula sp., occupying average 77.2 ± 14.9% of total number of MPB cells. The biomass was higher in the slightly muddy sand sites than that in the sand site, and showed different pattern of seasonal variation. The profile of vertical distribution of biomass was an exponential decrease trend with depth in sediments. The biomass proportions in the uppermost 3 mm were 57.6% and 37.8% with and without the presence of biofilm, respectively. The two dominant species were cultured in laboratory, and their photosynthetic parameters, rETRmax (relative maximum electron transport rate), α (light utilization coefficient) and E k (light saturation parameter) were derived from rETR (relative ETR)-irradiance curves by Imaging- PAM (pulse amplitude modulated) fluorometry. The rETR-irradiance curves showed no significant difference of photosynthetic activities between the two species. The areal potential production ranged from 0.74 to 2.22 g C m?2 d?1. 相似文献
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Tetraploid induction was carried out by inhibiting mitosis I in fertilized eggs ofChlamys farreri. Mitosis I was blocked with cold shock (5–7°C), Cytochalasin B (0.75 mg/L) and 6-dimethylaminopurine (6-DMAP) (60–75 mg/L)
when 60% fertilized eggs released polar body II at 20°C. At 4-cells embryo stage, the ploidy was determined by counting chromosome
number. In control groups, most embryos were diploids (72.22%) and aneuploids (24.78%). In Cytochalasin B, cold shock and
6-DMAP treated groups, tetraploids were respectively 10.51%, 4.08%, and 13.34%; aneuploids were 43.10%, 35.93% and 29.16%,
and triploids were 7.84%, 8.52% and 18.33%. At D-larva stage, ploidy was determined by flow cytometry (FCM). The ploidy analysis
of day 2 larvae showed diploids in control group and also in three treated groups. Juvenile scallops (0.2–0.3cm) which were
harvested in two control groups and two CB treated groups were all diploids through checking ploidy individually by FCM.
Contribution No. 3648 from the Institute of Oceanology, Chinese Academy of Sciences.
Contribution No. 238 from the Experimental Marine Biology Laboratory, Chinese Academy of Sciences.
Project funded by grant (No. 819-01-07) from the Chinese Science and Technology Ministry and also by “Hundred Talents Plan”
grant from the Chinese Academy of Sciences. 相似文献