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21.
It has been 60 years since the space physics as new branch of geophysics started to grow in 1957 when the space age was opened by a small satellite called sputnik. The knowledge of Earth and planetary space has been significantly extended and deepened, but the questions we are facing today are more challenging. A consensus reached is that we have to regard the Earth (planet) as an integrated system including all spheres from the inner core to the magnetosphere, and we should try to investigate some questions standing on the ground of interdisciplinary study, especially those questions related to Earth’s (planetary) evolution. Space environment as the outer part of a planetary system, commonly exists in all planets but also exhibits strong diversity. Here, we introduce the short history of basic ideas and methods of comparative study, the advantages on understanding of some issues of global scale, and the prospect from comparative perspective.  相似文献   
22.
西秦岭武山杨河礼县固城一带的原"泥盆纪"地层中,发现了大量属于早石炭世的牙形刺、珊瑚和有孔虫化石,为该区地层的重新划分提供了直接的证据.这对于重新认识该区乃至整个西秦岭地区石炭纪古地理格局、地质演化历史、沉积相和沉积环境等都有重要的意义.  相似文献   
23.
The operation and power generation of utility-scale solar energy infrastructure in desert areas are affected by changes in surface erosion processes resulting from the construction of solar photovoltaic(PV) power stations. However, few studies have addressed the interactions between solar PV arrays and aeolian erosion processes. In this study, wind flow field characteristics and the vertical distribution of sediments were investigated in the near-surface transport layer at three different locations with respect to the solar PV arrays in a 200 WM-p PV power station in the central Hobq Desert, northwestern China. The results indicate that the sediment transport varied around the panels, with the greatest transport occurring between the panels, followed by behind and in front of the panels. The sediment fluxes of all of the observation sites obey an exponential function. The secondary flow field zones formed around the PV panels: the conflux accelerating zone between the panels, the resistance decelerating zone of the under panels, and the transition zone of the rapid velocity increase in front of and behind the panels. This resulted in a greater shear force in front of the panels under the downward flow diversion effect of PV panels, and the wind erosion depressions were finally formed here. The results of this study provide information for planning better technical schemes for wind-sand hazards at solar PV power stations, which would ensure operational stability and safety in desert areas.  相似文献   
24.
There is an urgent need for the development of a method that can undertake rapid, effective, and accurate monitoring and identification of fog by satellite remote sensing, since heavy fog can cause enormous disasters to China’s national economy and people's lives and property in the urban and coastal areas. In this paper, the correlative relationship between the reflectivity of land surface and clouds in different time phases is found, based on the analysis of the radiative and satellite-based spectral characteristics of fog. Through calculation and analyses of the relative variability of the reflectivity in the images, the threshold to identify quasi-fog areas is generated automatically. Furthermore, using the technique of quick image run-length encoding, and in combination with such practical methods as analyzing texture and shape fractures, smoothness, and template characteristics, the automatic identification of fog and fog-cloud separation using meteorological satellite remote sensing images are studied, with good results in application.  相似文献   
25.
陈浩华  黄铭  葛修润 《岩土力学》2006,27(10):1819-1822
作为提高锚固性能的一种有效手段,端头扩大型土锚被广泛应用于实际工程。介绍了端头扩大型锚杆的各种扩孔方法,重点阐述一种新型的船锚式注浆张开型土锚。带有锚抓的新型土锚,不需要专门的扩孔机械,在注浆作用下能连续完成端头扩张与灌浆,具有施工方便、锚固面大、效果好等优点。通过对土锚进行张开试验,证明了在上海等软土地区通过灌浆压力使锚抓张开并形成扩大头是能够实现的。  相似文献   
26.
上达子堡金矿化区主要出露古元古界辽河群盖县岩组二岩段,是金成矿物质的矿源层。黄铁矿标型特征指示目前区内的剥蚀水平相当于中上部,按黄铁矿垂直分带规律,{210}+{100}、{210}习性晶体向深部有可能逐渐增加,因此,本金矿化区深部含金量可能高于浅部。  相似文献   
27.
蔚山铁铜矿位于安徽省无为县,是近年庐枞矿集区发现的新类型矿床,矿体主要赋存在石炭系黄龙组、船山组透辉石矽卡岩中,呈层状产出,主要矿石矿物为黄铁矿、磁铁矿等,少量黄铜矿,脉石矿物主要为方解石、透辉石等,矿床成因为矽卡岩型铁矿。从目前施工钻孔分析,形成矽卡岩的侵入岩体主要为花岗斑岩,结合地磁异常推断深部可能有规模更大的岩体,因此区内存在寻找(层控)矽卡岩型铁(铜)矿的较大潜力。  相似文献   
28.
高精度温度采集系统设计   总被引:1,自引:0,他引:1  
余德亮  魏威  蒋涌  黄兆富 《气象科技》2015,43(3):440-443
针对高精度温度采集的需求,设计了一个以低功耗单片机MSP430F149作为核心处理器,以PT100铂电阻为传感器的温度采集系统。为了提高系统的复用性,采用精密电阻法,从硬件设计上消除了恒流源电流漂移以及A/D转换电路参考电压精度对温度测量数据的影响。重点描述了系统设计方案,详细说明了恒流源选择的原则、电流偏差的消除以及AD7792转换器的操作步骤。实验结果表明,温度测量精度优于0.1 ℃。对比试验表明,系统稳定性良好,已应用于业务产品中。  相似文献   
29.
土地利用变化在空间维和时间维上是一个渐进的、不确定的复杂过程,而模糊理论正是解决不确定性现象的一种合适的方法,所以尝试运用模糊推理理论对土地利用变化进行深入的探讨.以江苏省南通市崇川区为研究区,建立了基于自适应神经模糊推理系统(ANFIS)的土地利用变化模糊推理模型.通过利用ANFIS训练获得模型的隶属函数及参数.并运用该模型对研究区进行土地利用变化的模拟和预测.研究结果表明,通过利用ANFIS建立的模型,基本上可以模拟研究区复杂而不确定的土地利用变化过程,同时ANFIS可以有效地简化模糊推理模型结构,使得模型更具灵活性.因此,为土地利用变化模拟提供了另一种可行的解决思路.  相似文献   
30.
In this paper, with the spatial analysis functions in ArcGIS and the county-level census data of 2000 in China, the population density map was divided and shown by classes, meanwhile, the map system of population distribution and a curve of population centers were formed; in accordance with the geographical proximity principle, the classes of population densities were reclassified and a population density map was obtained which had the spatial clustering characteristic. The multi-layer superposition based on the population density classification shows that the population densities become denser from the Northwest to the Southeast; the multi-layer clustering phenomenon of the Chinese population distribution is obvious, the populations have a water-based characteristic gathering towards the rivers and coastlines. The curve of population centers shows the population densities transit from the high density region to the low one on the whole, while in low-density areas there are relatively dense areas, and in high-density areas there are relatively sparse areas. The reclassification research on the population density map based on the curve of population centers shows that the Chinese population densities can be divided into 9 classes, hereby, the geographical distribution of Chinese population can be divided into 9 type regions: the concentration core zone, high concentration zone, moderate concentration zone, low concentration zone, general transitional zone, relatively sparse area, absolute sparse area, extreme sparse area, and basic no-man's land. More than 3/4 of the population of China is concentrated in less than 1/5 of the land area, and more than half of the land area is inhabited by less than 2% of the population, the result reveals a better space law of China’s population distribution.  相似文献   
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