基于信息量和逻辑回归耦合模型的黄土地震滑坡危险性分析

黄土地震滑坡危险性分析对黄土地区城镇化、工程建设的规划和地震灾害预防具有重要意义。以甘肃省定西市岷县—漳县交界处为研究区域,通过统计分析该区历史地震滑坡灾害数据,归纳并建立包含地震、坡度、坡高、坡向、地层岩性、年平均降雨量、河流流域和地貌类型等8个影响因子的评价指标体系,采用信息量模型、逻辑回归模型和信息量-逻辑回归耦合模型分别分析该区域黄土地震滑坡危险性。结果表明：(1)地震、河流和降雨是诱发黄土滑坡灾害发生的主要因素,其中地震因子贡献率最大;(2)研究区可划分为高、较高、中、低和极低危险区五个等级,其中高危险区主要集中于岷县、漳县与陇西县等地;(3)根据受试者工作特性(ROC)曲线精度检验结果,三种模型的AUC值分别为0.889、0.617和0.898,信息量-逻辑回归耦合模型结果的精确性相比其他两个模型更高。     

浙江舟山近海仔稚鱼时空动态变化及与环境因子的关系

为探明舟山近海海域仔稚鱼丰度的分布、出现概率及与环境因素的综合关系,进一步研究该海域渔业资源的补充机制,根据2019年3、4、7、11月在舟山近海海域开展的4个航次仔稚鱼生态调查资料,研究了舟山近海仔稚鱼的出现概率、群落结构(种类组成及优势种数量)的动态变化,探讨仔稚鱼群落的季节变化和对环境变化的响应,以及环境变化对仔稚鱼补充量的影响。结果显示:空间上,调查海区水深范围5～50 m,仔稚鱼集中分布于水深10～20m的近岸河口岛礁区;时间上的季节变化比较大,春夏季丰度高,冬季少。GLM模型结果显示:近岸河口型仔稚鱼在近岸出现的概率为0.65～0.95,在近海出现的概率为0.26～0.60;近海型仔稚鱼在近岸出现的概率为0.12～0.34,在近海出现的概率为0.32～0.54。仔稚鱼优势种春夏季各出现1种,秋冬季各出现2种,全年仔稚鱼优势种有4种。数量分布为:仔稚鱼种类数春季(19种)、夏季(16种)、秋季(10种)、冬季(5种),具有明显的季节性变化。按种类适温属性划分,调查海区仅出现暖温性和暖水性两种,其中暖温性15种(占已知适温类型种类的60%),暖水性10种(占40%);按生态类型...     

在IONESS系统中浮游介形类的昼夜垂直移动

根据IONESS系统对浮游动物的分层采样结果,研究浮游介形动物的昼夜垂直移动.浮游介形类存在着整个类群的昼夜垂直移动,白天其丰度最大值记录于200～300m层,并往上层水域递减,而夜间则明显往上层密集,丰度最大值提升至50～100m层;就物种多样性而言,由于工作水层(0～1000m)以深水层的众多种类于夜间上升至1000m以浅水层,导致工作水层内总种数由白天的49种剧增至夜间的78种,增幅达60%,各分层的种类数都有较明显的增加,750～1000m层的增幅最大,达150%,其次为50～100m层(增幅达125%);各种浮游介形类有不同的昼夜垂直移动模式,但绝大多数种类属于夜间上升型,少数种类属于不敏感类型,极少数种类却具夜间下降的移动特点.浮游介形类虽具明显的昼夜垂直移动,但这一变动往往局限于一定水深范围,从而反映出介形类的层状分布特点,可划分为广深分布型、上层分布型、中层分布型和下层分布型.     

Sedimentary records of eutrophication in the Changjiang Estuary upwelling area over last 100 a

The upwelling area in the Changjiang Estuary was selected to collect the core, where the red tide occurred frequently and hypoxic existed. The total organic carbon （TOC）, total nitrogen （TN）, biogenic silica （BSi） and stable organic carbon isotopic ratios（δ13 Corg） were determined on the 210pb-dated sediment core. The concentrations of TOC, TN, BSi as well as their sedimentation fluxes have in- creased to some extent since the 1970s. TOC and TN fluxes increased about 45%, 36% respectively. The average δ13 Coorg value in the core was -23.67 ×10^-3 which remained nearly constant before the 20 century. The δ13 Corg values increased after the 1900s, two marked increases were observed from the 1950s and the 1970s. A simple δ13 Cors model was used to estimate the contribution of terrigenous and marine organic matter inputs for the sediment, which indicated the increase in accumulation since the 1970s has been almost exclusively marine. The increasing of marine organic matter accumulation （TOC, TN and BSi） was corresponding with the increasing of fertilizer consumption and the NO3-N budgets from the Changjiang River. The riverine runoff of fertilizers and nutrients stimulated the algae blooming. Enhanced primary production resulted in an enrichment of organic matter in the sediment. These data support the hypothesis that anthropogenic nutrient loading has been a significant factor on the eutrophication in the Changjiang Estuary.     

Some Unresolved Issues in Ocean Pipes Aspirating Fluid

This paper reviews the dynamics of ocean pipes aspirating fluid and presents a selective review of the research undertaken on it. It focuses on the equations of motion, fluid-solid interaction at the inlet of the free end of the pipe, the stability mechanism of pipes aspirating steady fluid, etc. In particular, some unresolved or partly resolved issues on these important aspects are discussed. Finally, the promising future development in this area is discussed.     

智利外海南极褶柔鱼的形态学及部分生物学特征

描述了智利外海南极褶柔鱼Todarodes filippovae的形态特征,并参考前人研究资料,确定了其分类地位,同时对其作了初步分析。鉴定认为:该种系柔鱼科、褶柔鱼亚科、褶柔鱼属的南极褶柔鱼;其最北分布可到27°57′S,比原先文献报道的35°S偏北;渔获物的调查期间的胴长为157～366mm,体重为65～960g,性腺成熟度以Ⅰ、Ⅱ期为主,占总样本的71%。同时,还建立了胴长与体重、胴长与角质额喙长的关系式。     

Isotopic tracing of ore-forming source materials for Dexing porphyry copper deposit of Jiangxi, China

Dexing copper deposit is the biggest porphyry copper deposit in China. By researching isotopes of C,Si and Cu from the samples of Tongchang and Fujiawu ore-field, the authors found that δ13CPDB values of siderite were close to the δ13CPDB value of original magma; δ30Si values of the samples at the ore-forming stage were close to the δ30Si value range of magma, δ30Si values of partial samples were far away from it; Cu isotopic compositions of massive chalcopyrite formed at the early ore-forming stage are higher than that of veinal chalcopyrite formed at the later ore-forming stage. The results show that ore-forming materials were mainly derived from the porphyry body, and part of them were from wall rock materials.     

东昆仑中带金矿成矿地质特征

东昆仑中带 ,发现和查明和金矿有蚀变构造岩型、隐爆角砾岩型、矽卡岩型和石英脉型 4种矿化类型 ,其中前两者为金的主要成矿类型。研究表明 ,构造和岩浆作用是该区金矿成矿两个最主要的成矿条件。成矿显示与以闪长玢岩为代表的印支期浅成 超浅成岩浆岩密切相关 ,且金矿床及闪长玢岩等浅成 超浅成岩均受NW向剪切带的脆性复活构造控制而产出。金的成矿具深源、浅成的明显表现     

最低成本Internet实验室的建设

介绍一种最低成本 Internet实验室的建设方案。该方案适用于一般的大、中、小学 ,核心是使目前广泛使用的 Novell网支持 TCP/ IP协议 ,采用代理服务器通过拨号方式进入 Internet,使建设费和使用费大大降低。     

近断层地震下楼层竖向加速度影响因素分析

现阶段基于性能的抗震设计思想不仅关注结构自身体系的安全,而且保护非结构构件在地震作用下使用功能完好.对于工业建筑结构,生产设备在地震作用下受损会影响震后功能恢复.加速度敏感型非结构构件一般采用楼层加速度指标来量化其地震损伤程度.以三个不同高度的钢抗弯框架规则结构体系为研究对象,采用与竖向目标谱匹配的近断层非脉冲和脉冲地...