随机地震模型及反应谱分析

本文以实际地震加速度的频谱特性和相位谱特性为依据，仿概率统计理论中的高斯概率密度函数，建立了随机地震加速度频数学模型。     

DEM内插算法对坡度的影响

本文以干旱、半干旱地区的渭干河-库车河三角洲绿洲为研究区域,利用样区的1:50000的矢量地形图为数据源,通过对不同插值算法生成的DEM计算坡度,坡度计算像元值分别采用25m、50m、100m、1.50m、200m,5个分级.通过对比研究发现:在坡度小于27°时,不同的算法对坡度具有显著的影响,而大干27°时,算法不会...     

三个文蛤家系双列杂交设计在两种环境下的配合力及杂种优势分析

A 3×3 complete diallel cross comprising three families of the clam Meretrix meretrix(P1, P2 and P3) was used to determine the combining ability of parental families and heterosis of F1 under indoor and openair environments for growth traits. Analysis of variance for shell length and whole body weight indicated highly significant cross effects, environment effects and the interaction of cross by environment. General combining ability(GCA) and specific combing ability exhibited great variation among crosses and between two environments. Pooled over environments, P2 was the top combiner among the three parental families for both traits studied. The cross of P1 and P3 had the highest SCA. Additionally, significant reciprocal effects were observed. For individual environment, about half of the crossbred combinations showed favorable Mid-parent heterosis(MPH)(1%) for the shell length and whole body weight. Our data has shown that non-additive genetic and reciprocal effects constituted the major sources of genetic variation for both shell length and whole body weight, which indicates that crossbreeding among selective families could further explore the heterotic effects.     

Regional Fault Systems of Qaidam Basin and Adjacent Orogenic Belts

The purpose of this paper is to analyze the regional fault systems of Qaidam basin and ad-jacent orogenic belts. Field investigation and seismic interpretation indicate that five regional fault sys-tans occurred in the Qaidam and adjacent nment.qin belts, controlling the development and evolution of the Qaidam basin. These fault systems are: (1)north Qaidam-Qilian Mountain fault system; (2) south Qaidam-East Kunhm Mountain fault system;（3）Altun strike-slip fault system; (4) Elashan strike-slip fault system, and (5) Gansen-Xiaochaidan fault system. It is indicated that the fault systems controlled the orientation of the Qaidam basin, the formation and distribution of secondary faults within the basin,the migration of depocenters and the distribution of hydrocarbon accmnulation belt.     

江汉平原东北缘末次冰消期沉积物粒度特征及环境意义

麻城剖面位于江汉平原东北缘山地丘陵与平原过渡带半封闭的宽浅碟形洼地,是江汉平原北缘末次冰消期代表性沉积剖面.沉积环境主要由山麓坡洪积相和沼泽相组成,形成年代为距今18.00～8.60 ka.麻城剖面粒度组成主要以粉砂为主,达60.73％,其中,粗粉砂达40.83％.剖面粒度变化可划分为7个变化阶段.结合剖面的岩性与沉积...     

Pseudofrenelopsis fossils from Cretaceous gypsum beds in Guixi,Jiangxi Province,China and their geological significance

Compressed fossil plants were found in the gypsum beds of the Zhoujiadian Formation in Guixi City, Jiangxi Province, China. The cuticular features of two species of Pseudofrenelopsis (Cheirolepidiaceae) were examined by scanning electron microscopy in this study: Pseudofrenelopsis papillosa Cao ex Zhou and Pseudofrenelopsis guixiensis Bainian Sun et Dai, sp. nov. A detailed analysis of the internode epidermis, and the adaxial and abaxial leaf cuticles of the two species, was performed, extending our knowledge of the morphological and anatomical characteristics of the extinct Pseudofrenelopsis. A new species, Pseudofrenelopsis guixiensis sp. nov., is proposed based upon comparison of its cuticular features. It differs from previously published species in that it has hairs on the abaxial surfaces of its leaves, sometimes shares subsidiary cells on the surfaces of internodes, lacks a hypodermis, and has no papillae on its epidermal cells. Because the distribution of fossil Pseudofrenelopsis is restricted to the Lower Cretaceous, the Early Cretaceous age of the Zhoujiadian Formation is affirmed. The fossils of Pseudofrenelopsis show obvious xeromorphic characteristics, such as apparent thickening of the cuticles, subsidiary cells with obvious papillae, and anticlinal walls with strong cutinization, and they are found associated with gypsum beds and close to red beds. All of these features indicate an arid climate.     

Geochemical Characteristics of Gold Polymetallic Deposits as Exemplified by the Laozuoshan Deposit,Heilong jiang,China

From the studies of ore deposit geologic settings,sulfur isotopes,lead isotopes,carbon isotopes and oxygen isotopes,fluid inclusions and petrochemistry in this paper,the authors have drawn a conclusion that the ore-forming hydrothermal solutions are the high-temperature magmatic hydrothermal solutions for the gold ore deposit,and at the same time,the involvemety of crustal materials can not be ruled out .It is the first time that the authors have proposed that the Laozuoshan gold-ploymetallic ore deposit in Heilongjiang Province was formed in the calc-alkaline series environment at the margin of an active continent.     

广西大厂矿田铜坑深部隐伏矿体立体定量预测建模与可视化研究

广西大厂矿田长坡-铜坑矿区矿床形成与分布的主要控制因素有地层岩性、岩浆岩体和断层、褶皱构造.结合大厂矿田多年来积累的地质资料信息,提取了钻孔、坑道采样化验数据与地质体的几何取点等矿床隐伏矿体预测专题数据,建立了各种地质体几何模型;以此为基础进行控矿地质条件的定量分析,以立体单元形式对地质空间进行分割抽样,提取了立体单元控矿作用定量化指标;通过一种有效的矿床三雏数学模型建立方法,对矿床地下三维空间中隐伏矿体进行了定位、定量预测和结果验证,并开发了预测结果的三维可视化动态查询系统.     

农业生态系统可持续性评价研究进展

在大量查阅国内外文献资料的基础上,阐述了国内外农业可持续性评价指标体系的选取标准与选取方法,在此基础上,综述了国内外农业可持续评价方法及评价尺度等研究进展情况。发现国内农业可持续性评价指标过多且以农业经济方面的指标为主,指标之间重叠现象严重,对生态环境、政策性和指导性指标重视不够,而且评价方法有待进一步完善。最后,针对农业可持续性评价中存在的问题提出了一些建议,以期对国内农业的可持续评价研究有所借鉴。