云南新平药用蛇纹石矿物学及医疗机理分析     

石能学  李旭俊  段永莉 《云南地质》2011,30(1):89-91

新平蛇纹石是近年才开发的矿物药,因其具有特殊TO型三八面体层状结构及5类活性基因,而能吸附、过滤、分解氟化合物,成为预防、治疗地氟病的重要药源。  相似文献   

强震作用下岩质斜坡动力响应特性的大型振动台试验方案设计     

邹威  许强  刘汉香 《地质灾害与环境保护》2011,22(1):87-91

为了深入研究斜坡变形破坏机理,为汶川地震诱发次乍地质灾害提供理论解释,通过振动台试验模拟汶川地震过程.在参考已有实验和研究成果的基础上,对大型振动台物理模型进行设计,介绍模型箱、模拟范围、模型相似关系、模型岩层材料、各监测断面的位置和传感器的布置,编制地震波加载制度.结果表明,拟定的大型振动台模型试验设计方案是合理的.  相似文献   

2008—2018年中国手足口病时空分异特征   总被引：1，自引：0，他引：1  

李颉  郑步云  王劲峰 《地球信息科学学报》2021,23(3):419-430

手足口病是一种在婴幼儿中多发的常见传染病,对儿童的身体健康具有重要影响。为揭示我国手足口病的时空分异特征,为手足口病的防控提供科学依据,本文选取自2008年手足口病被列为丙类传染病以来至2018年中国手足口病发病率为研究数据,运用全局莫兰指数、Getis-Ord G_i ^*、新兴时空热点分析和标准差椭圆等空间统计方法对中国手足口病的整体和局部时空分布模式、特征和趋势进行了分析。结果显示：① 2008—2018年我国手足口病发病率呈现显著的空间聚集性,且聚集的强度显著增高;② 我国手足口病发病的热点区域主要集中在东南沿海地区,且较明显向内陆以及北部沿海地区扩张,而冷点区域主要集中在西北内陆以及东北地区;③ 我国手足口病的新兴时空热点模式以振荡的热点为主,新增热点主要出现在云南、重庆和四川,而冷点分布区域相对稳定,且冷点大部分以加强的、持续的模式出现;④ 手足口病高发病率区域在2008—2018年期间主要向西南方向移动,但在2008—2009年、2013—2014年以及2017—2018年存在向北部移动的趋势,同时2018年手足口病在东—西方向上的分布范围显著增大。总体来说,我国手足口病在南方地区高发。  相似文献   

The response law of far-field seismic ground motion of the Wenchuan earthquake and its damaging mechanism in the Loess Plateau     

Xiaowu Pu  Lanming Wang  Ping Wang  Xiufeng Tian  Shiyang Xu  Shaofeng Chai  Haitao Guo 《地震研究进展（英文）》2022,2(3):100114

A series of housing collapses and other serious damage was caused by the 2008 Wenchuan M_S 8.0 earthquake in the seismic intensity Ⅵ areas of the Loess Plateau, which is hundreds of kilometers away from the epicenter, and which showed a remarkable seismic intensity anomaly. The seismic disasters are closely related to the seismic response characteristics of the site, therefore, the systematic study of the far-field seismic response law of the Wenchuan earthquake in the Loess Plateau is of great significance to prevent the far-field disaster of great earthquake. In this paper, the seismic acceleration records of several bedrock stations and loess stations from the seismogenic fault of the Wenchuan earthquake to the Loess Plateau were collected, and the attenuation law of ground motion along the propagation path and the characteristics of seismic response on the loess site are studied, and the mechanism of amplification effect of ground motion is analyzed based on the dynamic feature parameters of the loess site obtained through the HVSR method. Taking a typical loess site of thick deposit as the prototype, a series of shaking table tests of dynamic response of loess site models with different thicknesses were carried out. Amplification effect, spectral characteristics of acceleration in model sites were analyzed under the action of a far-field seismic wave of the Wenchuan earthquake. The results show that seismic attenuation on the propagation path along the NE strike of the seismogenic fault to the Loess Plateau is slower than that in other directions, and the predominant period range of ground motion on bedrock site of the Loess Plateau presents broadband characteristics. Because the natural periods of loess sites with thick deposits are within the predominant period range of bedrock input wave, loess sites appear significant amplification effect of ground motion, the horizontal acceleration of ground motion exceeds 0.1 ?g, the seismic intensity reaches 7°. The thicker the loess deposit is, the more significant the change of spectral characteristics of ground motion on loess sites, and the narrower the predominant period range of ground motion becomes, and the closer it is to the natural period of loess sites. Therefore, for some old houses on thick loess sites, the poor seismic performance and strong seismic response eventually led to their collapses and damages because their natural periods are very close to the predominant period of ground motion of the Wenchuan earthquake on thick loess sites; For these damaged high-rise buildings, the resonance effect might be the main reason for their damages because their natural periods are included in the predominant period range of ground motion of the Wenchuan earthquake on thick loess sites.These research results would provide a basis for seismic disasters prediction and evaluation and seismic design of construction engineering in the Loess Plateau.  相似文献   

基于阶段式传播模型COVID-19防控措施的量化评估分析     

朱连华  谭岩  肖惠文  王露薇  李安琪  何陈涛 《南京气象学院学报》2020,12(3):364-372

基于病毒动力学传染机制,构建了考虑不同时期防控措施影响下的新型冠状病毒肺炎（COVID-19）阶段式传播模型.依据空间上的严重性将全国划分为三类疫情区,对各疫情区传染人数进行了阶段式模拟.结合上述模拟结果,进一步量化评估了各疫情区所采取的如武汉交通管制、对口支援湖北和小区封闭式管理等措施对抑制病毒传播的影响.结果表明,阶段式传播模型能够较好地模拟出各疫情区不同时期传染人数的变化特征,政府采取的交通管制和小区封闭式管理等防控措施大幅减少了传染人数,感染人数呈现出大幅下降的趋势,有效抑制了COVID-19的大规模扩散.  相似文献   

阿坝州饮水中硒和氟元素与大骨节病关系研究   总被引：1，自引：0，他引：1  

何锦  安永会  贾小丰  吴玺  李戍 《地下水》2012,(2):9-10

通过测定阿坝州四个大骨节病县饮用水中微量元素硒、氟的含量情况,探讨大骨节病与饮用水硒与氟元素的相关关系,为防治大骨节病提供科学依据。采集阿坝州病区与非病区水样,测定其中硒、氟元素含量,并运用SPSS17.0软件对测定结果进行分析统计。研究表明:阿坝州饮用水中硒、氟元素平均含量为0.47 ug/L～2.32ug/L,0.08 mg/L～0.38 mg/L,病区饮用水中硒、氟与非病区有明显差异(t分别是2.12,3.26,p<0.01),病区硒、氟元素与大骨节患病率之间有明显负相关关系。阿坝州大骨节饮用水中硒元素和氟均与大骨节病有密切关系,建议除进行必需的补硒措施防治大骨病以外,还应该辅助性的增加水氟含量已保证人体需要。  相似文献   

地震作用下含弱面斜坡变形破坏实验研究     

王来贵  闫杰  马乐  何峰 《工程地质学报》2012,20(4):471-477

为了研究含弱面斜坡在强震作用下变形破坏规律,对含单一弱面的3组斜坡模型模拟地震作用下的变形破坏,并用数字散斑相关方法对实验结果进行处理,得到斜坡模型位移和应变。从实验结果可以发现:位移和应变变形均集中在弱面上,随着震动的持续,这种变形积累最终导致斜坡发生破坏; 模型对比中可以发现,在斜坡体内弱面越深则斜坡稳定性越强,在斜坡体内弱面越长则斜坡稳定性越弱。分析模型最初在顶部出现裂缝和沿弱面发生滑动的原因。  相似文献   

转基因水稻"竹转68"病害发生风险的初步研究     

袁红旭  许新萍  郭建夫  张建中  李宝健 《广东海洋大学学报》2001,21(4):52-56

采用抗病性鉴定和田间隔离小区试验病害调查相结合的方法,研究了转抗真菌基因"RC24"的转基因水稻"竹转68"的抗病性和病害发生规律,对"竹转68"田间释放后病害发生的风险进行了初步预测.试验结果表明,"竹转68"对纹枯病具有较高的抗病性,对稻瘟病的抗病性也有显著提高且存在田间抗病性.进一步的田间隔离小区试验结果表明"竹转68"田间释放后,病害发生轻,表现较好的综合抗病能力.  相似文献   

Shaking table tests on the lateral response of a pile buried in liquefied sand   总被引：3，自引：0，他引：3  

J.R. Dungca  J. Kuwano  A. Takahashi  T. Saruwatari  J. Izawa  H. Suzuki  K. Tokimatsu 《Soil Dynamics and Earthquake Engineering》2006,26(2-4):287-295

This paper presents an experimental study on the lateral resistance of a pile subjected to liquefaction-induced lateral flow. To observe the soil surrounding the pile during liquefaction, it was modeled as a buried cylinder that corresponded to a sectional model of the prototype pile at a certain depth in the subsoil. In order to create a realistic stress condition in the model ground, the model was prepared in a sealed container and the overburden pressure was applied to the ground surface by a rubber pressure bag. The model pile was actuated back and forth through rods attached on each side by an electro-hydraulic actuator.This paper focuses on observing the deformation of the liquefied soil surrounding the pile when a large relative displacement between the pile and the soil is induced. The loading rate effect on the lateral resistance of the pile in the liquefied sand and the influence of the relative density are also investigated.Test results show that a larger resistance is mobilized as the loading rate becomes higher. When the loading rate is higher, the cylinder displacement required for the lateral resistance becomes smaller. It has been also observed that as the relative density of the soil increases, dilatancy of the soil in front of the pile also increases.  相似文献   

中国中部寄生虫病的景观控制     

F. Mark Danson  Patrick Giraudoux  David Pleydell  Philip S. Craig 《遥感学报》2007,11(5):727-730

多房棘球绦虫（Echinococcus multilocularis）的幼虫期导致罕见而致命的肝病即人类的泡型包虫病（HAE）。绦虫在狐狸（或狗类）与一些小型哺乳类动物之间以寄生虫-寄主的方式进行循环传播。中国中部一些地区的人类泡型包虫病属于地方流行病,在部分乡村的发生概率达到15%。本文研究如何利用遥感数据并基于地区景观特性获取该流行病清晰地空间危害分布图。遥感数据分析的结果显示,人类居住地附近的草地或灌木是HAE传播的一个主要危险区域,从空间分布上看,这些区域是小型哺乳动物等中间寄主的聚集处。  相似文献