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51.
重力、航磁资料在花岗岩型铀矿成矿研究中的应用 总被引:3,自引:2,他引:3
本文利用重磁场资料对我国南方一些花岗岩体的侵位状态和岩浆动力场进行了分析,并按动力场的强弱对岩体进行了分类。根据重力资料对苗儿山-越城岭、诸广山和贵东花岗岩体的反演计算,讨论了这些岩体的深部分布形态,提出了岩浆流动的3种方式,指出了富大铀矿床、大型铀矿聚集区的赋存部位及其与航磁异常的密切联系。 相似文献
52.
运用复变函数法和保角映射法对无限介质土中的衬砌结构进行分析.通过引入两个势函数将弹性介质的控制方程解耦成两个Helmholtz方程.利用所得势函数的通解,得到无限土介质和衬砌结构的位移和应力的表达式,利用无限介质与衬砌结构之间的连续性条件和衬砌结构内边界上的边界条件,可确定波函数展开式中的末知系数,并给出动应力集中系数的数值结果. 相似文献
53.
According to calculation results of ocean chlorophyll concentration based on SeaWiFS data by SeaBAM model and synchronous ship-measured data, this research set up an improved model for CaseⅠand CaseⅡwater bodies respectively. The monthly chlorophyll distribution in the East China Sea in 1998 was obtained from this improved model on calculation results of SeaBAM. The euphotic depth distribution in 1998 in the East China Sea is calculated by using remote sensing data of K490 from SeaWiFS according to the relation between the euphotic depth and the oceanic diffuse attenuation coefficient. With data of ocean chlorophyll concentration, euphotic depth, ocean surface photosynthetic available radiation (PAR), daily photoperiod and optimal rate of daily carbon fixation within a water column, the monthly and annual primary productivity spatio-temporal distributions in the East China Sea in 1998 were obtained based on VGPM model. Based on analysis of those distributions, the conclusion can be drawn that there is a clear bimodality character of primary productivity in the monthly distribution in the East China Sea. In detail, the monthly distribution of primary productivity stays the lowest level in winter and rises rapidly to the peak in spring. It gets down a little in summer, and gets up a little in autumn. The daily average of primary productivity in the whole East China Sea is 560.03 mg/m2/d, which is far higher than the average of subtropical ocean areas. The annual average of primary productivity is 236.95 g/m2/a. The research on the seasonal variety mechanism of primary productivity shows that several factors that affect the spatio-temporal distribution may include the chlorophyll concentration distribution, temperature condition, the Yangtze River diluted water variety, the euphotic depth, ocean current variety, etc. But the main influencing factors may be different in each local sea area. 相似文献
54.
The weight-specific respiration rate (μl O2 mg−1 AFDW h−1) of three species of leech from Lake Esrom, Denmark, Glossiphonia concolor, G. complanata and Helobdella stagnalis was measured in a closed stirred chamber with a micro electrode. At declining oxygen concentration (mg O2 l−1) all three species expressed moderate ability to regulate respiration, in G. concolor and G. complanata down to 2 mg O2 l−1, in H. stagnalis down to 0.75 mg O2 l−1. Survival in anoxia was measured in closed bottles. The time to 50% survival (LD50) was 30 days in G. concolor at 20 °C and 30 and 4 days in H. stagnalis at 10 and 20 °C, respectively. The results were discussed in relation to habitat and spatial distribution of the three species in the lake. 相似文献
55.
Vertical dynamic and thermodynamic characteristics of urban lower boundary layer and its relationship with aerosol concentration over Beijing 总被引:1,自引:0,他引:1
By utilizing observational data from a 325 m tower of the Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences (CAS) on March 19-29, 2001 and August 11-25, 2003, a comprehensive study was conducted on the vertical dynamical and thermodynamic characteristics of the urban lower boundary layer (ULBL) and its relationship with aerosol concentration over Beijing. Firstly, a comparative analysis was made on the gradient data (wind, temperature and humidity), ultrasonic data (atmospheric turbulences) and air-quality observations at different tower heights (47, 120 and 280 m). Secondly, a diagnosis was made to reveal the major features of normalized variances of velocity and temperature, turbulence kinetic energy as well as their relationship with aerosol concentrations. Furthermore, the characteristics of the ULBL vertical structure and the TSP concentration/distribution variations during a sand/dust weather process were also analyzed. The outcome of the study showed that under unstable stratification, the normalized variances of velocity (σu/u*, σv/u*, σw/u*) and temperature (σT/T*) at 47 and 120 m heights fit the Monin-Obukhov similarity (MOS) framework and the fitting formulas were given out accordingly. According to the stratification parameter (z′/L), the stable ULBL could be divided into 2 zones. With z′/L<0.1, it was a weakly stable zone and MOS framework was applicable. The other was a highly stable zone with z′/L>0.1 and the normalized velocity variances tended to increase along with higher stability, but it remained constant for normalized temperature variances. At daytime, the near-surface layer includes two heights of 47 and 120 m, while 280 m has been above it. The ULBL analysis in conjunction with a sand/dust weather process in Beijing in March 2001 indicated that the maximum concentration of Total Suspended Particulates (TSP) at 320 m reached 913.3 μg/m3 and the particles were transported from the upper to lower ULBL, which was apparently related to the development process of a low-level jet and its concomitant strong sinking motion. 相似文献
56.
通过对腾格里沙漠东南缘沙坡头人工固沙区油蒿和柠条叶片稳定碳同位素分辨率(△)和N 含量的测定,研究了不同种植方式下油蒿和柠条叶片△ 和 N 含量的季节变化及其关系。结果表明:在不同种植方式下,两种植物的△ 与 N 含量在不同月份之间均存在显著差异。油蒿叶片 △ 极显著高于柠条的:在不同种植方式下,油蒿单种下 △ 显著高于混种,柠条则反之。 油蒿叶片 N 含量极显著低于柠条的:不同种植方式下柠条叶片 N 含量无显著差异,而单种油蒿叶片 N 含量则显著低于混种。在 △ 与 N 含量的关系中,柠条叶片 △ 与 N 在两种生境、单种和混种下均极显著正相关,雨明柠条叶片 N 含量可以作为其 △ 与 N 含量的季节变化及其关系在不同微生境有所差异。 相似文献
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59.
客源地分布的集聚特征是客源市场空间结构研究的重要内容。针对现有客源集中指数不能横向对比及难以解释驱动因素的问题,论文提出了支持引入不同影响因子参数的客源地集中指数“tourCI”计算方法,建立了基于tourCI指数的客源地空间结构解释概念框架,给出tourCI的多维度描述方式和意义解析,以测算不同影响因素下的客源地分布集聚特征。以大理古城位置微博签到提取的客源数据进行实证研究,结果表明:基于政区维度的tourCI反映出云南省内本地客源对大理古城客源分布特征产生了重要影响,省外客源分布相对均衡;基于距离维度的tourCI刻画了大理古城客源分布随目的地距离的变化规律,由近及远呈现“弱—强—弱—均衡”的指数变化模式;经济维度tourCI显示来自一线城市的游客高度集中在经济水平较高地区,来自新一线城市的游客分布相对均衡,其余城市的客源分布受经济影响较大。理论与实证研究证明了tourCI指数对客源地空间结构集聚特征及驱动因素具有较好的解析能力,有助于丰富旅游地理研究的方法体系。 相似文献
60.
仿刺参水溶性海参皂苷的分离制备及抗真菌活性的研究 总被引:9,自引:0,他引:9
利用海洋生物资源进行天然抗真菌新药的开发,从冻干海参加工废液中提取了水溶性海参皂苷,并对其抗真菌活性进行了研究。采用大孔吸附树脂法提取水溶性海参皂苷,经Libermann Burchard反应等对提取物的性质进行鉴定后,利用管碟法对所得提取物的抗菌活性进行了测定,并利用琼脂稀释法测定了所得水溶性海参皂苷对6株供试真菌的最低抑菌浓度(MIC)。提取物在Molish反应、沉淀反应和泡沫实验中均为阳性,说明提取物中确含有皂苷类成分;在Libermann Burchard反应中,液体的颜色处在红色与紫色之间,显示提取物可能是1种三萜类皂苷。水溶性海参皂苷对6株供试真菌均具有显著的抑制作用,且在浓度为0.5~4 mg/mL的范围内,其抑菌活性与所用浓度之间呈明显的正相关性;在浓度为4 mg/mL时,水溶性海参皂苷对6株供试真菌抑制活性的大小依次为裂殖酵母菌、啤酒酵母菌、白色念珠菌、葡萄炭疽病原菌、黄瓜枯萎病原菌和黑曲霉,海参皂苷对6株真菌的MIC值依次分别为0.002,0.016,0.063,0.063,0.125,0.250 mg/mL。 相似文献