南岳电线积冰标准冰厚气候特征     

张剑明  李兴宇  叶成志  杨加伦  刘彬  丁知明 《气候与环境研究》2015,20(2):209-219

利用1957~2012年南岳高山观测站逐日覆冰资料,对南岳覆冰标准厚度和覆冰日数的时间演变、突变和周期变化进行分析,并推算出南岳各重现期的标准冰厚,结果表明:1)南岳南北向和东西向标准冰厚年代际变化非常相似,呈现偏大—偏小—偏大—偏小—偏大的年代际变化;冰冻日数在20世纪60年代中后期之前,90年代中后期之后冰冻日数偏少,60年代中后期到90年代中后期冰冻日数偏多。2)冰冻在1~4月、10~12月均有发生,其中1月出现天数最多,占全年的31.8%。3)滑动t检验分析发现,南岳东西向和南北向标准冰厚在20世纪60年代末有减小的突变,冰冻日数在近56年没有出现明显突变。4)Morlet小波和小波功率谱分析发现,南北向和东西向标准冰厚存在显著的2~3年、4~6年振荡周期;冰冻日数存在显著的2~4年、5~7年振荡周期。5)基于Pearson III型概率分布统计发现,各重现期东西向标准冰厚均较南北向标准冰厚要大,其中20年一遇南北向和东西向标准冰厚分别为76.33、85.22 mm,10年一遇南北向和东西向标准冰厚分别为60.86、69.57 mm。6)分析气象要素对覆冰的影响发现,覆冰期气温较无覆冰期要低,相对湿地要大,能见度要小,覆冰期风向以偏北风为准,无覆冰期风向以偏南风为主,覆冰期平均风速较无覆冰期风速要小。  相似文献   

Social interactions can affect feeding behaviour of fish in tanks     

S.A.L.M. Kooijman   《Journal of Sea Research》2009,62(2-3):175

Fish from the same clutch of eggs, so of the same age and family, can differ substantially in size after some time in a tank as result of social interactions. On the basis of computer simulation studies I here demonstrate that it is possible to mimic this empirical observation using the rules of the standard Dynamic Energy Budget (DEB) model, supplemented with a simple stochastic module for interaction between individuals that have identical parameters. The remarkable result is that length-at-age of two individuals in a tank where the number of food particles is kept constant closely follows von Bertalanffy growth curves with very different parameters, while in reality the individuals have identical parameters. The empirical observation demonstrates that fish are close to the supply end of the supply–demand spectrum and that age-based models for growth don't apply to supply systems. The significance of the result is discussed.  相似文献   

江苏省矿产资源储量套改结果分析     

杨建文 《江苏地质》2001,25(3):180-184

在汇总统计江苏省截至1999年底矿产资源储量套改数据的基础上研究分析有关资料,对江苏省矿产资源储量套改基本情况、重要矿产资源储量套改情况和套改结果进行了分析.就21世纪江苏面临的严峻的资源形势,提出了多项建议和对策.  相似文献   

宁夏地区GPS监测网建设、近期地壳运动特征及应力场与地震活动关系初探   总被引：1，自引：0，他引：1  

许文俊  赵卫明  柴炽章  金延龙  孙立新  郑斯华  三浦哲 《中国地震》2001,17(1):44-55

在阿拉善块体、鄂尔多斯块体和青藏块体交汇处的宁夏中部布设了GPS观测网,利用1996年以来的5期复测资料,分析了宁夏中部地区现今地壳运动状态,其结果为①宁夏中部地区在l996年12月至l999年5月间,有围绕鄂尔多斯西缘(P2测点)左旋运动的现象,银川盆地东侧的灵武断裂呈左旋逆走滑运动方式.该区主应力场方向为北北东-南南西(方位角为29.8°)方向,P2测站以南的中部地区向东位移,垂直形变量级明显大于水平形变量级,银川盆地及青藏块体呈上升状态,鄂尔多斯腹地的P1测站呈逐年下降趋势,在P3与P4测点间可能有一隐伏断裂存在.②在GPS测区附近中强地震前约1年,可观测到该区GPS测站的形变异常及主应力方向发生转变异常;测区附近中强地震前及周边地区强震前,该区GPS形变模拟矢量场能够预示未来地震的大体方位.这些结果可作为地震预测的特征值加以考虑.  相似文献   

我国现行地震标准和标准体系的分析与思考     

王同庆  付慧仙  黎益仕  周克昌  卢海燕  楼关寿 《震灾防御技术》2021,16(2):421-428

本文简述了我国地震标准化发展从无到有、从小到大经历的4个主要阶段，基于地震标准发布实施时间及业务领域分布统计对地震标准现状进行详细分析，阐述我国现行地震标准特点和存在的问题。在进一步研究地震标准体系的基础上，提出了完善建议，并初步构建了新的地震标准体系框架。通过对现行地震标准和标准体系的分析，提出地震标准化思考与建议，以期为进一步推进地震标准化工作提供借鉴。  相似文献   

Self-Affine Fractals and the Fractal Dimension of Fractured Rock Profiles     

Shi Xingjue  Xu Heming  Niu Zhiren  Fan ZengjieUniversity of Science  Technology of China  Hefei  China Seismologicai Bureau of Shanxi  Xi'an  China 《中国地震研究》1994,(3)

The measured profiles of laboratory fractured rocks should be self-affine fractal.The scaling properties of these profiles are described by two parameters-the fractal dimension D and the crossover length tc The D values of eight profiles are calculated by the ruler method and by the standard deviation method respectively.It is shown that if tc is far greater than the sampling step tc two methods yield the same results,although if it is far smaller than r,the D by the standard method will be about 1.20,while D by the ruler method will very close to 1.0,because two fractal dimensions,local and global,exist on two sides of tc In order to obtain the local fractal dimension which may be close to that of the standard deviation method,the ruler method must be modified.We propose a way to estimate the tc and to modify the ruler method.Finally,a profile having given D is generated in terms of the principle of non-integer order differential,through which the above two methods are verified and lead to the same res  相似文献   

成都标准基线场的设计及光干涉测量     

赵景瞻裴维礼  胡正元张胜书 J．雅克拉 M．波坦尼 《四川测绘》2004,27(2):88-91

本文较详尽地阐述了成都标准基线场的设计特点及其理论依据，并介绍了光干涉测量及其配合的EDM测量、光干涉测量计算结果和精度分析。  相似文献   

Sr and Pb isotopic composition of five USGS glasses (BHVO-2G, BIR-1G, BCR-2G, TB-1G, NKT-1G)   总被引：2，自引：0，他引：2  

Marlina Elburg  Pieter Vroon  Bas van der Wagt  Arnaud Tchalikian 《Chemical Geology》2005,223(4):196-207

Sr isotopic compositions and Rb / Sr ratios of three USGS glasses (BHVO-2G, BIR-1G, BCR-2G) are identical to those of the original USGS reference materials. NKT-1G and TB-1G give values of 0.70351 and 0.70558, respectively. Pb isotopic ratios were measured by the standard-sample bracketing technique on an MC-ICP-MS, which give results that are comparable in accuracy and reproducibility to double spike analyses. However, assessment of the reproducibility of the technique is hampered by inhomogeneous contamination of all USGS reference materials analysed. This contamination is likely to be the reason why the USGS glasses do not all have the same Pb isotopic composition as their unfused originals. Powdered glasses, distributed for characterisation of the glasses by bulk analytical techniques, do not all have the same Pb isotopic compositions as the solid glass material, and can therefore not be used for this purpose.  相似文献   

地学数据网络共享与交换研究的新进展——IAMG2006相关议题论文评述     

马小刚 《国土资源信息化》2006,(6):42-45

国际数学地质协会2006年会(IAMG2006)于2006年9月在加拿大多伦多召开。大会主题为“基于多源数据的定量地学”,共分14个分会场,其中第5分会场“通过开放式网络标准传递和发布地学信息”围绕国际地科联地学信息应用与管理委员会所组织的GeoSciML研究展开。通过现场交流和对论文的分析,本文重点介绍了GeoSciML研究的基本情况和最新研究进展。  相似文献   

Evaluation of the Iranian guideline for deismic rehabilitation of existing buildings     

Ali Reza Keyvani Boroujeni Majid Sadeghazar 《地震工程与工程振动(英文版)》2006,5(2):297-307

The Iranian Guideline for Seismic Rehabilitation of Existing Buildings （GSREB）, which is currently used for vulnerability assessment of existing buildings in Iran, is evaluated in this paper. The vulnerability of sample buildings of a variety stories with special steel moment resisting frames, designed according to the Standard No.2800 requirements, is assessed by GSREB. In the vulnerability assessment, different analysis methods were used and the results, in terms of usage ratio, defined as the ratio of the strength/deformation demand to the corresponding capacity, are compared. Numerical results show that some columns of these buildings do not satisfy the life safety performance criteria in the design hazard level. Moreover, the target displacement estimated by the Displacement Coefficient Method （DCM） is larger than the maximum displacement calculated by nonlinear dynamic analysis.  相似文献