ANALYSIS OF CLOUD-TO-GROUND LIGHTNING CHARACTERISTICS IN MESOSCALE STORM IN BELIING AREA          下载免费PDF全文

葛正谟  言穆弘  GuoChangming  郭昌明  张广庶 《Acta Meteorologica Sinica》1992,(4)

The research indicates that there is a positive correlation between the negative CG flash rate and the area of radarecho with its reflectivity being equal to or greater than 30 dBz in the mesoscale convective system in Beijing area.A max-imum of the positive CG flash rate exists at both the initial and the dissipating stages.The CG flashes are usually locatednear but not within the high reflectivity center.The negative flashes are associated with.the positions of the updraft re-gion,and with the regions of wind convergence and wind shear.Generally,the negative CG flashes are concentrative andthe positive ones are dispersive.  相似文献   

A PRELIMINARY STUDY OF SNOW MASS VARIATIONS IN CHINA OVER THE PAST 30 YEARS   总被引：1，自引：0，他引：1       下载免费PDF全文

李培基 《Acta Meteorologica Sinica》1992,(2)

Daily snow data for 2300 climate stations covering the period from 1951 through 1980 have been used to monitorand diagnose secular variations,year-to-year fluctuations,and the spatial characteristics of snow variation trends inChina.An examination of time series reveals that there is a strong teleconnction to ENSO,to major volcanic eruptions,as well as to the CO_2-induced warming.The country-wide snow mass variations are positively correlated with globalmean temperature,increasing during the current warming period and decreasing during the recent cooling period priorto the mid 1960s.A synchronous relationship exists between El Nino/Southern Oscillation and snowy winter in China.The year-to-year snow fluctuations seem to be generally out of phase with volcanic activity.The anomaly map showsthat snow mass increased in high altitudes and moist regions,while it decreased in arid lowland and the southern bounda-ry zone during the warming period.The potential CO_2-induced changes in snow mass will further aggravate the regionaldifferentiation between high mountains and lowlands,between moist and arid regions.The number of snow cover dayswill decrease in the northern lowlands,and snowfall will increase in the Qinghai-Xizang Plateau,high mountains,andthe lower reaches of the Changjiang(Yangtze)River.  相似文献   

Numerical analysis of the interaction of soil-structure under earthquake loading   总被引：1，自引：0，他引：1  

章根德  宁书成 《地震学报(英文版)》1997,10(4):489-495

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Historical-Dynamic Integrative Classification of Basinogenesis and Ore-Forming Basins     

Chen GuodaChangsha Institute of Geotectonics  Academa Sinica  Changsha 《中国地质大学学报(英文版)》1993

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尖晶石族矿物的热辐射性质研究   总被引：8，自引：1，他引：8  

姜泽春  陈大梅 《矿物学报》1993,13(4):382-390

本文主要研究晶石族矿物在５０－６５０℃，２－４０μｍ波长范围内的红外光谱发射率和总发射率。文中共研究了三十余种尖晶石族矿物的发射率。测试结果表明，尖晶石族矿物的发射率的大小受其成分、晶体结构、温度和波长的制约。过渡族中的着色离子将大大增加矿物在红外短波段的发射率。  相似文献   

热处理低温钠长石的EPR和X射线衍射研究     

富毓德 《矿物学报》1989,9(4):296-303

利用电子顺磁共振(EPR)和X射线衍射方法研究了天然和热处理钠长石单晶。热处理在500—850℃水热条件下完成。在外加磁场B平行于晶体c~*轴的方向上,测量了加热前后Fe~(3+)的EPR谱和线宽△B随温度和加热时间的变化。结果显示,线宽随Al、Si无序的增大而增加。由此得出结论,在低温钠长石中,Fe~(3+)位于Al~(3+)占据的T_1(o)位置,在被研究的温度范围内,Fe~(3+)未参与四面体位置T间Al、Si交换。谱线的加宽主要是由在Fe~(3+)邻近位置上Al、Si无序的增大引起的,同时与观测到的晶胞参数变化有关。在Al、Si无序更强的晶体中,Fe~(3+)谱变得极宽。  相似文献   

Ag_2S-Cu_2S-PbS和Ag_2S-Cu_2S-Bi_2S_3体系相关系及相关矿物共生组合研究     

吴大清 《矿物学报》1987,(1)

本文用抽空石英管法对三元硫化物体系Ag_2S-Cu_2S-PbS和Ag_2S-Cu_2S-Bi_2S_3在500℃的相图进行了研究。 Ag_2S-Cu_2S-PbS体系500℃相关系,受方铅矿和固溶体f.c.c.(Ag_xCu_(2-x)S)、b.c.c.(Cu_xAg_(2-x)S)所控制。在接近PbS-Cu_2S连线处有一液相区。随温度下降,方铅矿可与Cu_2-Ag_2S二元系上所有各相平衡共存。 Ag_2S-Cu_2S-Bi_2S_3体系在500℃时则包含六个固溶体,即块硫铋银矿、铜银铅铋矿、杂硫铋银矿、硫铋铜矿、CuBi_3S_5、Cu_3Bi_5S_9和新合成“C”(Ag_(1.1)Cu_(4.8)Bi_(5.8)S_(12))。最令人感兴趣的是无铜、无铅的铜银铅铋矿(Ag_2Bi_4S_7)合成成功。 以上二个三元系中矿物稳定性及共生关系也根据相图研究结果进行了讨论。  相似文献   

莱河矿超结构的高分辨电镜研究     

邹本三  郭可信 《矿物学报》1987,(1)

用高分辨电子显微术和光学衍射技术研究了莱河矿的三种超结构类型——3C_1,2C,3C_2。超结构的存在是由于Fe~(2+)空位的不同有序分布产生的。通过观察象与模拟象的比较,建立了相应的结构模型。  相似文献   

锂绿泥石的红外光谱研究     

刘高魁  彭文世 《矿物学报》1987,(1)

本文给出了产于河南和贵州的锂绿泥石红外光谱,以及光谱中各谱带的频率、吸收强度、主要谱带的归属和灼烧样品的红外光谱。这两个矿物的光谱与以前发表的锂绿泥石的光谱有差别,而和白云母、伊利石的光谱相似;文中给出了它们的鉴定特征。根据红外光谱认为,锂绿泥石的结构可能是复杂的,不含有H_2O形式的水;它更接近二八面体型结构。锂绿泥石灼烧到453℃时,OH根全部脱失,结构向非晶态转化,到800℃后,转变成莫来石、非晶态SiO_2和LiO_2。  相似文献   

徐水五香坡粘土中混合层矿物的研究     

姬素荣  夏琤  苏明迪 《矿物学报》1987,(2)

五香坡粘土是由石英钠长斑岩风化而成的一种粘土。该粘土主要由高岭石、蒙脱石和伊利石组成,而且伴生了少量的混合层粘土矿物。混合层粘土矿物通过用乙二醇处理与加热至520℃(1.5h)后的X射线衍射鉴定,它们是伊利石-蒙脱石规则混合层矿物和伊利石/蒙脱石不规则混合层矿物。在粘土中发现了混合层粘土矿物,这为伊利石和蒙脱石之间的转变提供了依据。  相似文献