2014年鲁甸M_S6.5地震后地质灾害发育分布特征          下载免费PDF全文

杨秀元  姚亚辉 《地震工程学报》2018,40(5):1078-1083

2014年云南鲁甸“8·03”M_S6.5地震造成了重大人员伤亡和财产损失，诱发了大量滑坡、崩塌、泥石流等地质灾害。基于对鲁甸县龙头山幅（G48E006006）地质灾害调查数据和对典型地质灾害的剖析，震后地质灾害发育分布有特征如下：（1）震后地质灾害较震前成倍增长，震前地质灾害多以中小型浅层崩滑为主，地震诱发了诸如甘家寨、红石岩等大型—特大型滑坡、崩塌，大量沟谷崩滑堆积物为泥石流储备了丰富的物源；（2）震中高烈度区域地质灾害密度大，沿发震断裂带NNE—NE向构造密集发育，震中区龙头山镇地质灾害发育最为集中；（3）地质灾害呈带状分布，明显受控于河流水系（牛栏江、沙坝河、龙泉河等）、公路（昭巧二级公路、沙乐公路）等线性地貌单元和线性工程，人类活动影响明显。  相似文献   

2013年岷县—漳县M_S6.6地震前水氡浓度的临界慢化现象研究     

王熠熙  李赫  王博  杨朋涛  王俊  向阳  王喜龙  李悦 《地震》2018,38(1):128-138

基于临界慢化理论, 以2013年7月22日甘肃岷县—漳县M_S6.6地震前南北构造带及邻区水氡浓度观测资料为例, 逐一计算了表征临界慢化现象的自相关系数和方差。 研究结果表明, 2013年岷县—漳县M_S6.6地震前, 10个台点水氡浓度资料表现出较明显的临界慢化现象, 且出现慢化现象的观测点空间分布具有一定丛集性, 慢化持续时间呈现出由南向北迁移的特征。 综合分析认为, 临界慢化方法可以有效识别水氡资料蕴含的慢化信息, 这些早期异常信号对判定前兆异常所处阶段以及深入理解前兆资料变化的物理内涵具有重要的科学意义。  相似文献   

基于FFT-MA的随机介质建模方法          下载免费PDF全文

杨修伟  朱培民  毛宁波  徐志伟  肖丹 《地球物理学报》2018,61(12):5007-5018

随机介质是描述地球介质小尺度非均匀性的有效模型，在地震散射波场分析、储层描述等领域具有广泛应用，快速准确的随机介质建模方法是开展相关研究的基础与前提.本文首次将FFT-MA（Fast Fourier Transform Moving Average）算法引入到随机介质建模研究中，分析了该方法与传统随机介质建模方法相比具有的优势，并提出了基于FFT-MA的非平稳随机介质建模方法.建模实验表明，与传统的基于谱分解定理的随机介质建模方法相比，基于FFT-MA的方法在空间域产生随机数序列，使随机数序列与结构参数分离，因此，随机数序列与所建模型存在空间上的对应关系，可以分区域建模和局部修改模型.在非平稳随机介质模型建模时，滑动窗口的大小可以根据自相关长度变化而变化，避免了每个采样点都建立一次完整大小的模型，提高了建模效率.因此，FFT-MA随机介质建模方法能准确构建满足自相关函数要求的平稳及非平稳随机介质模型，具有建模效率高、灵活、实用的优点.  相似文献   

3D P-WAVE VELOCITY STRUCTURE AT THE NORTHEASTERN MARGIN OF ORDOS BLOCK     

HAN Xiao-ming  Liu Fang  ZHANG Fan  CHEN Li-feng  LI Juan  LI Shuan-hu  YANG Hong-ying 《地震地质》2018,40(1):215-231

Using the 7 100 absolute first arrivals of P waves and 91 513 relative P arrival times of 726 events at the northeastern margin of the Ordos block since 2009, the 3D fine structure of P wave velocity within the depth of 15km in the crust was inverted by the double difference seismic tomography method. The results show that there exist obvious high-speed continuous bodies in the northwest of the study area, and their lateral areas increase gradually with depth, while the velocity of east and south is relatively low. The velocity inhomogeneity exists and differs at different depths. The lateral differences of velocity are related to seismicity and faults. The 5~15km depth profile shows that earthquakes tend to occur in the area with relatively high velocity or high speed transition zones, which to some extent reflects the fragility of regional crustal media and the strong differential movement of faults in vertical and horizontal directions where the crust body is easy to absorb and store strain energy and generate major earthquakes. A "Y"-shape low-velocity channel is present in the lower crust around Liangcheng, corresponding to the NW-trending Heilaoyao-Shahukou fault set, which may reveal the migration path of the Late Tertiary-Quaternary basalt eruption. The Helingeer M6.2 earthquake in 1976 was related to the formation of the locking section of the thermal welding in this area. The three-dimensional fine structure of P wave velocity presented in this paper provides intuitive seismological evidence for physical and chemical properties of crustal media and the deep tectonic environment of earthquake preparation.  相似文献   

RESEARCH ON PASSIVE SERVO SEISMIC ROTATIONAL ACCELERATION SENSOR WITH LARGE DAMPING     

QU Ming-zhe  GAO Feng  YANG Xue-shan  YANG Dong-xia 《地震地质》2018,40(5):1170-1178

Many strong motion records show that under the strong seismic vibration of, the torsional disfigurement of building structures is a common and serious damage. At present, there are no special sensors for measuring seismic rotation in the world. Most of the experts obtain rotational components through observing deformation, theoretical analysis and calculation. The theory of elastic wave and source dynamics also prove the conclusion that the surface of the earth will rotate when an earthquake occurs. Based on a large number of investigations and experiments, a rotational acceleration sensor was developed for the observation of the rotational component of strong ground motions. This acceleration sensor is a double-pendulum passive servo large-damped seismic rotational acceleration sensor with the moving coil transducer. When an earthquake occurs, the seismic rotational acceleration acts on the bottom plate at the same time. The magnetic circuit system and the middle shaft fixedly connected to the bottom plate follow the bottom plate synchronous vibration, and the moving part composed of the mass ring, the swing frame and the moving ring produces relative corners to the central axis. The two working coils mounted on the two pendulums produce the same relative motion with respect to the magnetic gaps of the two magnetic circuits. Both working coils at this time generate an induced electromotive force by cutting magnetic lines of force in the respective magnetic gaps. The generated electromotive forces are respectively input to respective passive servo large damper dynamic ring transducer circuits and angular acceleration adjusting circuits, and the signals are simultaneously input to the synthesizing circuit after conditioning. Finally, the composite circuit outputs a voltage signal proportional to the seismic rotational acceleration to form a seismic rotational acceleration sensor. The paper presents the basic principles of the rotational acceleration sensor, including its mechanical structure diagram, circuit schematic diagram and mathematical models. The differential equation of motion and its circuit equation are derived to obtain the expressions of the main technical specifications, such as the damping ratio and sensitivity. The calculation shows that when the damping ratio is much larger than 1, the output voltage of the passive servo large damping dynamic coil transducer circuit is proportional to the ground rotation acceleration, and the frequency characteristic of bandpass is wider when the damping ratio is larger. Based on the calibration test, the dynamic range is greater than or equal to 100dB and the linearity error is less than 0.05%. The amplitude-frequency characteristics, the phase-frequency characteristics and their corresponding curves of the passive servo rotational acceleration sensor are acquired through the calculations. Based on the accurate measurement of the micro-vibration of the precision rotating vibration equipment, the desired result is obtained. The measured data are presented in the paper, which verify the correctness of the calculation result. The passive servo large damping rotational acceleration sensor has simple circuit design, convenient operation and high resolution, and can be widely applied to seismic acceleration measurement of earthquake or structure.  相似文献   

基于边际效应分析的海洋资源环境承载力评估          下载免费PDF全文

李爱  杨正先 《海洋开发与管理》2018,35(4):44-50

海洋资源环境的开发利用可视为将海洋资源环境作为生产投入要素的广义生产行为,因此受边际效应递减规律的制约。本研究基于资源环境边际效应的经济学视角,以对海洋资源环境破坏较大的填海造地建设为研究重点,通过基于GIS的海洋资源环境边际机会成本评估和基于边际效应分析的海洋资源环境承载力评估模型,建立海洋资源环境承载力的评估理论和方法,重新认识海洋资源环境承载力在海域管理绩效评估和科学决策中的重要作用,为区域海洋资源优化配置提供新的方法体系;关键成果是构建基于边际效应分析的海洋资源环境承载力评估模型,模型将海洋资源环境纳入宏观生产投入要素,由宏观要素的边际收益测算承载力极限阈值,其中对海洋资源环境的市场价值和非市场价值的正确评估是承载力评估的关键。  相似文献   

A Population Genetic Analysis of Continuously Selected Chlamys farreri Populations     

ZHANG Lu  LI Yuli  LI Yangping  YANG Zhihui  LI Yuqiang  WANG Yangfan  WANG Shi  BAO Zhenmin 《中国海洋大学学报(英文版)》2018,(4)

This study applied an optimized one-step 2b-RAD library construction strategy and performed simplified genome sequencing of 539 individuals from three continuously selected Chlamys farreri populations. SNP screening was performed using RAD typing software and population genetic parameters for the continuously selected populations from three generations(G1, G2, G3) were determined. The results showed that the optimized one-step 2b-RAD library construction strategy greatly simplified the experimental process, making it suitable for efficiently constructing a large number of libraries. A total of 18450 SNP markers were identified, which evenly distributed throughout the genome. Population genetic analysis of these three generations showed that the mean value of observed heterozygosity was 0.275 ± 0.177, 0.272 ± 0.181 and 0.275 ± 0.166, respectively. Meanwhile, the mean value of expected heterozygosity was 0.275 ± 0.141, 0.274 ± 0.145 and 0.280 ± 0.133, respectively. The Wright's fixation index(F) was 0.04291, 0.04976 and 0.06685, respectively. Markers deviated from Hardy–Weinberg equilibrium accounted for 10.34%, 12.64%, and 23.11%, and the Shannon diversity index was 0.0999 ± 0.0404, 0.0921 ± 0.0388 and 0.0733 ± 0.0308. FIS(also known as the inbreeding coefficient) of the three populations was 0.0256, 0.0323 and 0.0468, respectively. We suggested that the 2b-RAD method is well suited to population genetic studies of aquacultured organisms. Moreover, our results indicated that the continuous selection affected the population genetic structure of the cultured Penglai-Red scallop, but the change was not significant; therefore, population selection should continue.  相似文献   

基于平均分组和叠加相关的GPS信号捕获方法     

杨久东  吴风华  王文军 《大地测量与地球动力学》2018,38(8):828-831

针对目前GPS软件接收机C/A码捕获信噪比门限高、捕获速度慢的问题，提出一种基于平均分组和叠加相关的GPS弱信号捕获方法。首先，基于平均相关处理技术降低C/A码捕获过程中的自相关损耗，提高对微弱信号的捕获能力；然后，利用叠加相关提高相干运算的运算效率，并采用线性插值提高自相关函数性能；最后，利用频偏校正和内插进一步提高C/A信号的捕获精度。理论分析和仿真实验均验证，该方法能够在较低的信噪比下实现GPS信号捕获，且精度较高、运算量较低。  相似文献   

中西医结合治疗2型糖尿病30例总结          下载免费PDF全文

杨巧玉  刘筱  彭芸 《应用海洋学学报》2018,34(9):16-18

目的：观察二甲双胍联合养阴降浊汤治疗2型糖尿病的临床疗效。方法：将60例2型糖尿病患者随机分为治疗组和对照组各30例，治疗组采用二甲双胍联合养阴降浊汤治疗，对照组单用二甲双胍治疗。比较2组综合疗效及血糖血脂水平。结果：总有效率治疗组为86.7%，对照组为53.3%，组间比较，差异有统计学意义（P<0.05）；治疗组血糖血脂各项观察指标及对照组FPG治疗前后组内比较，差异均有统计学意义（P<0.05）；2组各项观察指标治疗后组间比较，差异均有统计学意义（P<0.05）。结论：二甲双胍联合养阴降浊汤能有效降低2型糖尿病患者的血糖，改善血脂，值得在临床上推广。  相似文献   

不同排列方式和间隙比下双圆柱流致振动特性研究   总被引：1，自引：0，他引：1  

刘巨保  杨明  岳欠杯  丁宇奇  姚利明 《海洋工程》2018,36(4):105-113

采用基于ALE的流固耦合分析方法,将圆柱体振动模型简化为平面双自由度质量-弹簧-阻尼系统,进行了计算参数无关性分析。对不同θ角和间隙比T下的双圆柱流致振动进行数值模拟,并与单圆柱振动计算结果进行比较,得到了不同θ角和间隙比T下中心圆柱的升阻力系数、流场分布和运动轨迹变化情况。通过分析发现小间隙比下由于两圆柱间的相互干扰,改变了中心圆柱的尾涡结构,导致了升力和阻力系数随不同θ角而发生变化;小间隙比下由于两圆柱间的相互干扰影响,均使中心圆柱的轨迹在不同θ角下发生了较大的变化,顺流向的振动频率与单圆柱振动时相比出现了多倍频,导致其运动轨迹发生了变化。  相似文献