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   

新疆康家石门子岩画病害调查及保护措施     

郑云峰  谌文武  张景科 《地震工程学报》2011,33(Z1)

位于新疆昌吉州呼图壁县的天山腹地的康家石门子岩画是一幅世界罕见的生殖崇拜岩画,绘在新近纪粉砂岩壁上,位于单斜砂砾岩崖体最下方。经过对岩画区域及载体的全面病害调查与分析,发现整个崖体被冲蚀的非常严重,其中较大的危害为雨水冲刷和裂隙的存在。通过多道瞬态面波勘探方法进行岩画内部裂隙的探测,依据文物保护的基本要求和现有的保护手段,初步提出了对康家石门子岩画的保护与防治措施的对策。  相似文献   

可液化场地桥梁桩基改进m值法研究     

唐亮  凌贤长  苏雷  高霞  李青华 《地震工程学报》2011,33(Z1)

为了合理分析可液化场地桥梁桩基侧向承载力进行了改进m值法的研究。基于振动台试验和m值法,建立了桩-土相互作用体系有限元分析模型;引入反映可液化砂层侧向承载力衰减状态的孔压比指标值Ru;将不同时刻对应墩顶配重惯性力作为体系外部激励施加于墩顶;通过不断试算液化过程中砂土的m值,保证桩的弯矩计算值与试验值吻合较好。建立了考虑孔压比效应的砂土m值衰减因子p与Ru之间关系式。最后,推荐给出可液化场地桥梁桩基侧向承载性能分析的改进m值法。  相似文献   

粤西沿海震动图的生成和研究     

熊厚  叶春明  黄文辉  丘学林  卫小冬 《华南地震》2011,31(4):85-97

震动图是描绘地震产生的地面运动和可能破坏情况的有效工具,主要包括峰值地面速度(PGV)等值线图、峰值地面加速度(PGA)等值线图和仪器烈度分布图等.基于华南数字地震台网记录到的2010年7月9日MS3.7级阳江地震的数据资料,利用SAC和GMT软件从记录到的地震波形数据提取地面运动参数,生成了PGV和PGA等值线图,并...  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   

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   

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   

Coral Diseases in the Indo-Pacific: A First Record   总被引：3，自引：0，他引：3  

Arnfried  Antonius 《Marine Ecology》1985,6(3):197-218

Abstract. . The so-called "band" diseases of reef corals, the White Band Disease (WBD) and the Black Band Disease (BBD), were observed in the Red Sea and in the Philippines. Since they were previously known only from the western Atlantic, this is the first record for the Indo-Pacific region. WBD is neither infectious nor contagious and the pathogen is unknown. BBD is highly infectious and contagious and is caused by the cyanophyte Phormidium corallyticum. Susceptibility to WBD occurs throughout the order Scleractinia, but the effects of the disease are most severe among Acroporidae. Susceptibility to BBD seems to be restricted to Faviidae, with Platygyra and Goniastrea species the most heavily afflicted. WBD cannot be influenced by any parameter tested so far. BBD can be enhanced by light and by water eutrophication, and its advance can be stopped by antibiotics. An active WBD seems to be a precondition for the origin of BBD.  相似文献   

对虾红肢病发病机制的研究     

赵增元  李天保  郭文  王勇强  李美芝  孙吉贵  宋万水  刘洪广 《海洋科学》1995,19(6):50-54

１９９０－１９９３年试验使用副溶血弧菌及溶藻弧菌感染获得成功。在试验过程中发现，环境及对虾体质对驿虾感染死亡率影响甚大，恶劣环境中的死亡率比优良环境中的死亡率出８３．３％；体质差的对虾感染的后的２４ｈ死亡率是正常对虾的２．５－３倍。为此，在对虾虾养殖生产中除应注意消灭病原菌外，还应注意优化养殖环境与增强对虾体质的问题。  相似文献   

新一代喹诺酮药物防治中国对虾幼体细菌性疾病的试验     

战文斌  俞开康 《海洋湖沼通报》1993,(3):83-87

新一代喹诺酮药物——6—F—喹啉—3—羧酸(商品名齐复康Ⅱ号)对中国对虾幼体的毒性,蚤状幼体、糠虾幼体、仔虾24hLC_(50)分别为16.3、21.3、45.8(×10~(-6));48hLC_(50)分别为8.1、12.5、30.0(×10~(-6));安全浓度(SC)分别为0.6、1.3、3.8(×10~(-6))。试验表明此药对防治对虾幼体细菌性疾病效果明显。0.5×10~(-6)。每天施药一次,连续三天,育苗池水中细菌总数由30750ind./ml减少到6850ind./ml,其中在TCBS培养基上能生长的细菌由22400ind./ml减少到1090ind./ml。  相似文献