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Theory and Application of Loss of Life Risk Analysis for Dam Break 被引量:2
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作者 孙月峰 钟登华 +1 位作者 李明超 李颖 《Transactions of Tianjin University》 EI CAS 2010年第5期383-387,共5页
The loss of life risk evaluation model for dam break is built in this paper.By using an improved Monte Carlo method,the overtopping probability induced by concurrent flood and wind is calculated,and the Latin Hypercub... The loss of life risk evaluation model for dam break is built in this paper.By using an improved Monte Carlo method,the overtopping probability induced by concurrent flood and wind is calculated,and the Latin Hypercube Sampling is used to generate random numbers.The Graham method is used to calculate the loss of life resulting from dam failure.With Dongwushi reservoir located at Hebei Province taken as an example,the overtopping probability induced by concurrent flood and wind is calculated as 4.77×10-6.Loss of life is 24 220 when the warning time is 0.25-1 h and flood severity understanding is vague,which indicates that the risk is intolerable.The losses of life under three other conditions are tolerable:warning time 0.25-1 h,and precise flood severity understanding;warning time more than 1 h,and vague flood severity understanding;warning time more than 1 h,and precise flood severity understanding. 展开更多
关键词 高出的概率 生活风险的损失 风险评价 水坝安全管理
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Debris Flows Risk Analysis and Direct Loss Estimation:the Case Study of Valtellina di Tirano,Italy 被引量:5
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作者 Jan BLAHUT Thomas GLADE Simone STERLACCHINI 《Journal of Mountain Science》 SCIE CSCD 2014年第2期288-307,共20页
Landslide risk analysis is one of the primary studies providing essential instructions to the subsequent risk management process. The quantification of tangible and intangible potential losses is a critical step becau... Landslide risk analysis is one of the primary studies providing essential instructions to the subsequent risk management process. The quantification of tangible and intangible potential losses is a critical step because it provides essential data upon which judgments can be made and policy can be formulated. This study aims at quantifying direct economic losses from debris flows at a medium scale in the study area in Italian Central Alps. Available hazard maps were the main inputs of this study. These maps were overlaid with information concerning elements at risk and their economic value. Then, a combination of both market and construction values was used to obtain estimates of future economic losses. As a result, two direct economic risk maps were prepared together with risk curves, useful to summarize expected monetary damage against the respective hazard probability. Afterwards, a qualitative risk map derived using a risk matrix officially provided by the set of laws issued by the regional government, was prepared. The results delimit areas of high economic as well as strategic importance which might be affected by debris flows in the future. Aside from limitations and inaccuracies inherently included in risk analysis process, identification of high risk areas allows local authorities to focus their attention on the "hot-spots", where important consequences may arise and local(large) scale analysis needs to be performed with more precise cost-effectiveness ratio. The risk maps can be also used by the local authorities to increase population's adaptive capacity in the disaster prevention process. 展开更多
关键词 风险分析 损失评估 泥石流 意大利 直接经济损失 案例 阿尔卑斯山 管理过程
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Effects of Orlistat - induced Weight Loss on Cardiovascular Risk Factors in Obese Chinese Subjects
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作者 徐明彤 吴木潮 +3 位作者 黎锋 周淑娴 程桦 傅祖植 《South China Journal of Cardiology》 CAS 2003年第1期1-4,共4页
Objectives To observe the influence of weight loss induced by orlistat on several cardiovascular diseases risk factors in obese Chinese subjects. Methods Sixty obese Chinese patients participated in a 24 week clinical... Objectives To observe the influence of weight loss induced by orlistat on several cardiovascular diseases risk factors in obese Chinese subjects. Methods Sixty obese Chinese patients participated in a 24 week clinical trial. Participants were prescribed a slightly hypocaloric diet and exercise, then they were randomly assigned double -blind treatment with either orlistat 120 mg three times a day or placebo. Their body weight, blood pressure, fasting glucose, insulin, HbA1c, and serum lipid profile were performed before and after the weight loss intervention. Results After 24 weeks, orlistat -treated group lost more of their body weight than placebo group (6. 66 ± 0. 52 kg, 8. 44±4.08% and 1. 98 ± 0. 44 kg, 2. 44±1. 74 % , respectively, P < 0. 05) . Moreover, after treatment, orlistat - treated patients showed significant decreases in serum levels of total cholesterol, low density lipoprotein - cholesterol and high density lipoprotein - cholesterol ( P < 0.01), but in placebo group we found no change. Both systolic blood pressure and diastolic blood pressure fell significantly in orlistat - treated group. Fasting glucose and HOMA - IR in orlistat - treated group was distinctly reduced if compared with placebo group. Conclusions Weight loss resulting from orlistat treatment and slightly hypocaloric diet has produced favorable effects on several cardiovascular risk factors in obese Chinese subjects. 展开更多
关键词 Orlistat Weight loss Cardiovascular risk factors
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Flood Risk Analysis and Flood Potential Losses Assessment
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作者 高俊峰 Lorenz King +1 位作者 姜彤 王润 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2003年第1期1-9,共9页
The heavy floods in the Taihu Basin showed increasing trend in recent years. In this work, a typical area in the northern Taihu Basin was selected for flood risk analysis and potential flood losses assessment. Human a... The heavy floods in the Taihu Basin showed increasing trend in recent years. In this work, a typical area in the northern Taihu Basin was selected for flood risk analysis and potential flood losses assessment. Human activities have strong impact on the study area’s flood situation (as affected by the polders built, deforestation, population increase, urbanization, etc.), and have made water level higher, flood duration shorter, and flood peaks sharper. Five years of different flood return periods [(1970), 5 (1962), 10 (1987), 20 (1954), 50 (1991)] were used to calculate the potential flood risk area and its losses. The potential flood risk map, economic losses, and flood-impacted population were also calculated. The study’s main conclusions are: 1) Human activities have strongly changed the natural flood situation in the study area, increasing runoff and flooding; 2) The flood risk area is closely related with the precipitation center; 3) Polder construction has successfully protected land from flood, shortened the flood duration, and elevated water level in rivers outside the polders; 4) Economic and social development have caused flood losses to increase in recent years. 展开更多
关键词 圩田 太湖盆地 潜在损失评估 洪水危险地区 经济损失 社会损失 湖南
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中国农田磷流失风险评价及其关键驱动因素 被引量:1
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作者 郑博福 刘海燕 +4 位作者 吴汉卿 吴之见 刘忠 朱锦奇 万炜 《农业工程学报》 EI CAS CSCD 北大核心 2024年第2期332-343,共12页
农田面源磷流失是农业面源污染的重要原因之一,识别流域内农田磷流失风险的关键源区及其影响因子是面源污染控制的重要手段。基于磷指数模型开展2000—2020年中国农田磷流失风险评估,选取土壤有效磷含量、磷肥施用量为源因子,土壤侵蚀... 农田面源磷流失是农业面源污染的重要原因之一,识别流域内农田磷流失风险的关键源区及其影响因子是面源污染控制的重要手段。基于磷指数模型开展2000—2020年中国农田磷流失风险评估,选取土壤有效磷含量、磷肥施用量为源因子,土壤侵蚀模数、年径流深、农田和水体间归一化距离指数为迁移因子,结合GIS技术评估了中国农田磷流失的关键源区;在此基础上,利用随机森林法分析影响中国农田磷流失的关键因子,并通过结构方程模型揭示了农田磷流失风险指数与各因子的关系。结果表明:1)2000—2020年中国农田的磷流失的低、中、高、极高风险面积分别占农田总面积的43.8%、40.5%、13.4%、2.4%。2)中国农田磷流失在2000、2005、2010、2015、2020年高风险和极高风险总面积的年平均占比从大到小依次为:淮河流域、长江流域、珠江流域、东南诸河流域、松辽河流域、西南诸河流域、黄河流域、内陆河流域、海河流域。3)影响农田磷流失风险的关键源因子和迁移因子分别为土壤有效磷含量和归一化距离指数,其重要性特征值分别为129.53和65.12,土壤有效磷含量是农田磷流失最主要影响因子。4)磷流失风险指数与源因子指数、迁移因子指数呈极显著正相关,选取的14个指标对磷指数的解释度达0.62,其中源因子和迁移因子对磷指数的贡献率分别为0.77、0.19(P <0.001)。研究结果可为中国农田磷流失风险评估提供科学参考,对中国农业面源污染的宏观防控及战略决策具有重要意义。 展开更多
关键词 农田 面源污染 磷指数模型 磷流失 风险评价 关键因子 随机森林 结构方程模型
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Recognition and Measurement of Losses Caused by Systematic Risk in Damages of False Statements
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作者 杜莹芬 张文珂 《China Economist》 2014年第2期114-125,共12页
Based on the single-factor market model,this paper examines the confirmation basis and measurement of the losses arising from systematic risk in the civil damages of false statements.The paper argues that the systemat... Based on the single-factor market model,this paper examines the confirmation basis and measurement of the losses arising from systematic risk in the civil damages of false statements.The paper argues that the systematic risk not only affects the investment in securities during times of financial crisis,but also causes losses in daily securities trading.The paper carries out an empirical analysis on the existence of ft coefficient for China's listed companies within a period of one year,and examines the impact of systematic risk on the losses of investors.The civil damages of false statements should take full account of the losses arising from systematic risk.After analysis,the paper uses the correlation coefficient to represent the ratio of losses arising from systematic risk of all the transactions of a particular stock during a certain period of time,and tries to develop two methods to measure the damages after adjusting the losses caused by the systematic risk The paper has a theoretical foundation for the estimation of losses caused by systematic risk,and matches the risks and returns.The result of the paper has provided an effective method of calculation in the determination of reasonable damages in the case of China Langfang Development Co.,Ltd. 展开更多
关键词 系统风险 损失估算 损害赔偿 陈述 计量 引发 民事赔偿 证券交易
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Smoking increases risk of tooth loss: A meta-analysis of the literature
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作者 Fumihito Sato Masashi Sawamura +4 位作者 Miki Ojima Keiko Tanaka Takashi Hanioka Hideo Tanaka Keitaro Matsuo 《World Journal of Meta-Analysis》 2013年第1期16-26,共11页
AIM: To quantitatively evaluate the impact of smoking on tooth loss.METHODS: We performed a Pub Med search to identify published articles that investigated the risk of tooth loss by smoking, from which RRs and their v... AIM: To quantitatively evaluate the impact of smoking on tooth loss.METHODS: We performed a Pub Med search to identify published articles that investigated the risk of tooth loss by smoking, from which RRs and their variance with characteristics of each study were extracted. The random-effects models were used to derive a pooled effect across studies. Potential sources of heterogeneity on the characteristics of the study and their influence on the pooled effect size were investigated using metaregression models. RESULTS: We identified 24 studies containing a total of 95973 participants for analysis. The pooled RR of ever-smokers compared with never- smokers was 1.73(95%CI: 1.60-1.86, P < 0.001). In meta-regression analysis, only the mean age of participants alone was identified as a statistically significant source of heterogeneity. The effect of smoking on tooth loss was stronger when the mean age of study participants was higher, indicating possible enhancement of tooth loss due to aging by smoking. RR was significantly lower in former smokers(1.49, 95%CI: 1.32-1.69, P < 0.001) than in current smokers(2.10, 95%CI: 1.87-2.35, P < 0.001), indicating the substantial benefit of smoking cessation for reducing the risk of tooth loss.CONCLUSION: Smoking is an independent risk factor for tooth loss regardless of many other confounders. Smoking cessation may attenuate this effect. 展开更多
关键词 META-ANALYSIS Oral health Relative risk SMOKING Tooth loss
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Risk of Hearing Loss Caused by Multiple Acoustic Impulses in the Framework of Biovariability 被引量:2
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作者 Hongyun Wang Wesley A. Burgei Hong Zhou 《Health》 2018年第5期604-628,共25页
We consider the hearing loss injury among subjects in a crowd with a wide spectrum of individual intrinsic injury probabilities due to biovariability. For multiple acoustic impulses, the observed injury risk of a crow... We consider the hearing loss injury among subjects in a crowd with a wide spectrum of individual intrinsic injury probabilities due to biovariability. For multiple acoustic impulses, the observed injury risk of a crowd vs the effective combined dose follows the logistic dose-response relation. The injury risk of a crowd is the average fraction of injured. The injury risk was measured in experiments as follows: each subject is individually exposed to a sequence of acoustic impulses of a given intensity and the injury is recorded;results of multiple individual subjects were assembled into data sets to mimic the response of a crowd. The effective combined dose was adjusted by varying the number of impulses in the sequence. The most prominent feature observed in experiments is that the injury risk of the crowd caused by multiple impulses is significantly less than the value predicted based on assumption that all impulses act independently in causing injury and all subjects in the crowd are statistically identical. Previously, in the case where all subjects are statistically identical (i.e., no biovariability), we interpreted the observed injury risk caused by multiple impulses in terms of the immunity effects of preceding impulses on subsequent impulses. In this study, we focus on the case where all sound exposure events act independently in causing injury regardless of whether one is preceded by another (i.e., no immunity effect). Instead, we explore the possibility of interpreting the observed logistic dose-response relation in the framework of biovariability of the crowd. Here biovariability means that subjects in the crowd have their own individual injury probabilities. That is, some subjects are biologically less or more susceptible to hearing loss injury than others. We derive analytically the distribution of individual injury probability that produces the observed logistic dose-response relation. For several parameter values, we prove that the derived distribution is mathematically a proper density function. We further study the asymptotic approximations for the density function and discuss their significance in practical numerical computation with finite precision arithmetic. Our mathematical analysis implies that the observed logistic dose-response relation can be theoretically explained in the framework of biovariability in the absence of immunity effect. 展开更多
关键词 risk of Significant Hearing loss INJURY DOSE-RESPONSE Relation for MULTIPLE ACOUSTIC IMPULSES Biovariability A Crowd With Heterogeneous Individual INJURY Probabilities
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Loan Loss Reserves (LLR), Expected Loss (EL), and Value at Risks (VaR)
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作者 Mohd Yaziz Mohd Isa Yap Voon Choong +1 位作者 David Yong Gun Fie Md. Zabid Hj. Abdul Rashid 《Journal of Modern Accounting and Auditing》 2015年第4期218-222,共5页
关键词 准备金 LLR 损失 贷款 EL VAR 风险 商业银行
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基于溃决机理的堰塞湖溃决快速风险评估方法研究
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作者 王琳 苑鹏飞 +3 位作者 钟启明 胡亮 单熠博 薛一峰 《自然灾害学报》 CSCD 北大核心 2024年第1期51-62,共12页
堰塞湖发生后极易形成溃决灾害链,亟需构建基于有限数据包的溃决快速定量风险评估方法。通过快速获取堰塞湖影响区域的三维地理信息,构建溃决-致灾的快速定量评估模型。基于堰塞湖坝体颗粒级配组成,实现精细化、简单化的稳定性快速评价... 堰塞湖发生后极易形成溃决灾害链,亟需构建基于有限数据包的溃决快速定量风险评估方法。通过快速获取堰塞湖影响区域的三维地理信息,构建溃决-致灾的快速定量评估模型。基于堰塞湖坝体颗粒级配组成,实现精细化、简单化的稳定性快速评价;基于冲蚀特性和崩塌过程溃决机理,实现溃口流量变化过程分析与洪水演进过程模拟(1 h内);基于极限学习机网络模型建立风险人口与生命损失的函数,实现了生命损失评估预警,明晰了溃决-致灾的灾害链效应。将其应用于唐家山堰塞湖实例发现:研究方法能够较好地预警溃决灾害链;开挖引流槽可降低堰塞湖的溃口峰值流量、最大流速、溃口宽度和溃决库容,但无法防止溃决发生;若不开挖引流槽,溃决库容将达到3.14×10^(8) m^(3),溃口峰值流量达到9343.35 m^(3)/s,溃口顶宽增大到151.6 m,开挖引流槽可使溃口峰值流量减少12.6%,溃决库容减少36.5%,降低了堰塞湖的溃决风险;当提前预警时间超过2 h后,及时疏散下游淹没范围内的居民可使生命损失率降低为0。研究方法可实现堰塞湖应急处置时的快速定量风险评估,并为其应急处置决策提供技术支撑。 展开更多
关键词 堰塞湖 稳定性 溃决过程 生命损失 风险评估 唐家山
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骨科患者术中下肢深静脉血栓风险增高的血流变化及影响因素
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作者 方敏 高兴莲 +3 位作者 王曾妍 柯稳 肖潇 梁元元 《护理学杂志》 CSCD 北大核心 2024年第10期64-67,共4页
目的探讨骨科患者术中下肢深静脉血栓(DVT)风险增高的血流变化特点并分析其影响因素,为手术室护理干预提供临床指导。方法选取151例骨科择期手术患者为研究对象,术中使用多普勒超声诊断仪观察下肢血流改变特征,并收集患者基本资料、手... 目的探讨骨科患者术中下肢深静脉血栓(DVT)风险增高的血流变化特点并分析其影响因素,为手术室护理干预提供临床指导。方法选取151例骨科择期手术患者为研究对象,术中使用多普勒超声诊断仪观察下肢血流改变特征,并收集患者基本资料、手术相关资料、术前实验室检查指标等,患者手术结束24 h内采血行D-二聚体凝血功能检测。结果D-二聚体检测结果显示,DVT高风险患者70例(46.36%),低风险81例(53.64%)。手术结束后DVT高风险患者下肢平均血流速度、血管内径显著低于或小于低风险患者(均P<0.05)。logistic回归分析显示,手术时间>120 min、凝血酶原时间(PT)>13.1 s、术中发生低体温和术中失血量>100 mL是骨科患者术中DVT风险增高的独立危险因素(均P<0.05)。结论骨科手术患者术中DVT发生风险较高,存在明显血流动力学改变。手术室护理人员需针对性地开展手术效率管理、术中低体温监测和预防、维持术中血容量稳定,有效降低骨科手术患者术中DVT发生风险。 展开更多
关键词 骨科手术 术中 下肢深静脉血栓 血流动力学 低体温 术中失血量 风险管理 手术室护理
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Risk of Hearing Loss Injury Caused by Multiple Flash Bangs on a Crowd
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作者 Hongyun Wang Wesley A. Burgei Hong Zhou 《American Journal of Operations Research》 2018年第4期239-265,共27页
A flash bang is a non-lethal explosive device that delivers intensely loud bangs and bright lights to suppress potentially dangerous targets. It is usually used in crowd control, hostage rescue and numerous other miss... A flash bang is a non-lethal explosive device that delivers intensely loud bangs and bright lights to suppress potentially dangerous targets. It is usually used in crowd control, hostage rescue and numerous other missions. We construct a model for assessing quantitatively the risk of hearing loss injury caused by multiple flash bangs. The model provides a computational framework for incorporating the effects of the key factors defining the situation and for testing various sub-models for these factors. The proposed model includes 1) uncertainty in the burst point of flash bang mortar, 2) randomness in the dispersion of multiple submunitions after the flash bang mortar burst, 3) decay of acoustic impulse from a single submunition to an individual subject along the ground surface, 4) the effective combined sound exposure level on an individual subject caused by multiple submunitions at various distances from the subject, and 5) randomness in the spatial distribution of subjects in the crowd. With the mathematical model formulated, we seek to characterize the overall effect of flash bang mortar in the form of an effective injury area. We carry out simulations to study the effects of uncertainty and randomness on the risk of hearing loss injury of the crowd. The proposed framework serves as a starting point for a comprehensive assessment of hearing loss injury risk, taking into consideration all realistic and relevant features of flash bang mortar. It also provides a platform for testing and updating component models. 展开更多
关键词 risk of SIGNIFICANT HEARING loss Mathematical Framework for Assessing INJURY risk Effective INJURY Area Decay of Acoustic Impulse along Ground Surface DOSE-RESPONSE Relation Fluctuations in Actual INJURY Numbers
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四川盆区油菜花期低温阴雨灾损评估及风险区划
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作者 赵艺 郭翔 +2 位作者 王鑫 杨德胜 王明田 《中国农业气象》 CSCD 2024年第6期629-642,共14页
花期低温阴雨是四川盆区油菜生产的主要气象灾害之一。本研究利用四川盆区1961-2020年101个气象站的逐日气象资料,1983-2000年油菜产量资料和干旱、低温冷害、连阴雨、大风、冰雹灾情资料,筛选花期低温阴雨灾害年份,采用数理统计方法获... 花期低温阴雨是四川盆区油菜生产的主要气象灾害之一。本研究利用四川盆区1961-2020年101个气象站的逐日气象资料,1983-2000年油菜产量资料和干旱、低温冷害、连阴雨、大风、冰雹灾情资料,筛选花期低温阴雨灾害年份,采用数理统计方法获取花期低温阴雨产量灾损率和致灾因子,通过相关性分析确定油菜花期低温阴雨致灾指标,并利用2001-2020年灾情资料进行检验;基于筛选出的低温、连阴雨关键致灾因子,采用回归分析法建立油菜花期低温阴雨灾害损失评估模型,并进行回代和预测检验,分析灾害风险区划和变化趋势。结果表明:(1)日平均气温≤7℃、过程持续天数≥1d是四川盆区油菜花期低温致灾指标,日平均气温≤7℃的负积温和≥3d过程持续降水量共同组成低温阴雨灾害的关键致灾因子;选用2001-2020年油菜花期低温冷害发生情况对指标进行检验,与实际情况相符。(2)选用1983-2000年的气象、产量、灾情数据建立四川盆区油菜花期低温阴雨灾损评估模型,模型对轻度、中度灾害损失评估等级与实际等级相同或相差1级的评估准确率在96%以上;重度、特重评估等级与实际等级相同的准确率为0,与实际等级相差1级的准确率为75%和0。选用2001-2020年油菜花期低温阴雨灾害发生情况对模型检验,与实际情况基本相符。(3)1961-2020年四川盆区油菜花期低温阴雨灾害风险偏高区域主要分布于盆区西南部、南部及东北部,以中-高风险为主;灾害风险偏低的区域集中于盆区西北部及中部,以低-次低风险为主。(4)气候变暖背景下,四川盆区油菜花期低温阴雨灾害高风险区域呈减少趋势,低风险区域呈增加趋势。综上分析,四川盆区油菜花期低温冷害指标结果可靠,低温阴雨灾损评估模型能够较好地评估灾害损失,可应用于农业气象业务服务;灾害风险区划结果可为四川油菜生产布局提供参考依据。 展开更多
关键词 四川盆区 油菜花期 低温阴雨 灾损评估 风险区划
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土地经营权入股的隐性失地风险与制度应对
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作者 谭贵华 《西南政法大学学报》 2024年第4期80-92,共13页
担心失地是制约土地经营权入股的重要因素。基于制度文本和实践纠纷的解析,土地经营权入股的失地风险主要为隐性失地风险——虽然在法律上享有收回土地的权利,但实际上难以收回、有效利用。其主要成因包括入股合同的约定欠周延,农地流... 担心失地是制约土地经营权入股的重要因素。基于制度文本和实践纠纷的解析,土地经营权入股的失地风险主要为隐性失地风险——虽然在法律上享有收回土地的权利,但实际上难以收回、有效利用。其主要成因包括入股合同的约定欠周延,农地流转和土地股份组织制度衔接不足,政府投资建设的农业设施的处置规则不明,以及农地纠纷解决机制效能不高。在风险应对方面,不应固守单一的组织法视角,而是需要坚持系统性思维,综合施策予以现实应对,重点包括强化合同治理提高入股合同的周延性,深化农地流转和土地股份组织制度的衔接,健全政府投资建设的农业设施的处置规则,以及构筑更加便捷高效的农地纠纷调处机制。 展开更多
关键词 土地经营权入股 失地风险 隐性失地 流转风险 农民权益
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基于FloodArea模型的成都主城区内涝风险评估
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作者 邓国卫 孙俊 +2 位作者 徐沅鑫 徐金霞 彭骏 《气象科技》 2024年第2期265-276,共12页
本文以成都主城区为例,运用气象数据、地理信息数据、社会经济统计数据及内涝灾情资料,通过多种常用分布函数的对比,选出重现期降水估算的最优函数,采用Pilgrim&Cordery法推求研究区的小时雨型,然后结合改进的基于FloodArea内涝模型... 本文以成都主城区为例,运用气象数据、地理信息数据、社会经济统计数据及内涝灾情资料,通过多种常用分布函数的对比,选出重现期降水估算的最优函数,采用Pilgrim&Cordery法推求研究区的小时雨型,然后结合改进的基于FloodArea内涝模型,开展了24 h历时20、30、50、100 a一遇降水情景内涝模拟,并利用修订的内涝公路风险等级标准和财产损失曲线,探讨100 a一遇降水情景下内涝交通风险等级和居民室内财产损失风险。结果表明:①GEV(Generalized Extreme Value Distribution)分布函数是成都主城区重现期降水估算的最优函数;主城区24 h历时小时雨型呈双峰型,且峰值出现在降水过程前部。②基于FloodArea模型,通过对输入数据或参数的改进,能够较好模拟城市内涝空间分布;各降水情景模拟结果显示高新南区、高新西区、青羊区内涝淹没范围占比相较其他地区偏高。③24 h历时100 a一遇降水情景内涝可造成成都主城区86.1%公路长度占比出行困难,其中一级风险公路长度占比为10.5%,二、三级风险公路长度占比分别为27.5%、28.4%,成华区内涝公路风险最高。④24 h历时100 a一遇降水情景内涝可造成居民室内财产潜在损失约占主城区GDP(Gross Domestic Product)的0.8%,其中武侯区财产损失风险最大,潜在损失占其GDP的1.6%。 展开更多
关键词 城市内涝 风险评估 财产损失 FloodArea模型 成都
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考虑人体与水流相互作用的溃坝洪水生命损失评估模型
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作者 彭铭 马福军 +4 位作者 沈丹祎 蔡一坚 石振明 周家文 刘西军 《工程科学与技术》 EI CAS CSCD 北大核心 2024年第1期127-137,共11页
溃坝洪水会给下游人民群众造成巨大的生命损失,开展溃坝洪水造成的生命损失风险定量评估对应急抢险救灾具有重要的现实意义。本文在已有生命损失贝叶斯网络HURAM1.0模型基础上,引入了人体稳定性物理模型,考虑人体与水流相互作用关系,对... 溃坝洪水会给下游人民群众造成巨大的生命损失,开展溃坝洪水造成的生命损失风险定量评估对应急抢险救灾具有重要的现实意义。本文在已有生命损失贝叶斯网络HURAM1.0模型基础上,引入了人体稳定性物理模型,考虑人体与水流相互作用关系,对处于洪水中的人先进行稳定性判定,并进行溺水判定,运用蒙特卡洛模拟方法,综合了水深和水流速对生命损失的影响,建立HURAM2.0模型;并将该模型应用于唐家山堰塞坝溃坝洪水生命损失分析。结果表明:HURAM2.0模型建立了水流流速对生命损失影响的定量关系,更精确地刻画了人体在水流中的稳定性和求生能力,相比HURAM1.0模型对较强洪水强度条件下的生命损失预测结果更准确。同时,在本文建立的模型中,除水深度、洪水严重程度变化不大,其余变量的敏感性均有所上升,其中居民区住宅层数、在建筑物中庇护情况和溃坝时长等变量对模型计算结果的最大影响程度分别增加142%、95%和93%,加强了模型在低、中、高3类洪水强度下的解释性,与HURAM1.0相比在贝叶斯反演分析中更占优势。在唐家山堰塞坝溃坝风险分析中,HURAM2.0能区分出不同水流速条件下的生命损失,更符合实际情况,即开挖泄流槽前风险大、死亡率高,在现场勘测和开挖泄流槽后风险及死亡人数大大降低,建议结合预警疏散以降低生命损失风险。 展开更多
关键词 溃坝 人体稳定性 生命损失风险 贝叶斯网络 堰塞坝溃决洪水
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基于AHP耦合Sigmoid函数的重载铁路黄土边坡风险分析
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作者 李浩然 李铮 +3 位作者 马遥 卓崔瑶 周通 赵志荣 《铁道标准设计》 北大核心 2024年第7期48-52,91,共6页
重载铁路具有大轴重、高密度、大运量的运输特点,黄土边坡路基段一直是重载铁路运营的高风险区段,现有风险评价方法尚无法满足其风险量化分析的需求。利用层次分析法AHP耦合Sigmoid函数的方法,围绕事故发生概率和损失两个方面对重载铁... 重载铁路具有大轴重、高密度、大运量的运输特点,黄土边坡路基段一直是重载铁路运营的高风险区段,现有风险评价方法尚无法满足其风险量化分析的需求。利用层次分析法AHP耦合Sigmoid函数的方法,围绕事故发生概率和损失两个方面对重载铁路黄土边坡工程展开风险定量评价。首先以边坡滑塌事故调研和稳定性控制理论为基础,明确黄土边坡的失稳影响因素,建立重载铁路黄土边坡稳定性评价模型和边坡失稳危害性评价模型;然后应用层次分析法建立黄土边坡稳定性评价模型指标权重,并提出各级影响因素的指标赋值方法;而后引入基于朴素贝叶斯理论的Sigmoid函数,构建边坡稳定服役概率、风险判断矩阵和黄土边坡的风险等级确定方法;最后以朔黄铁路某站高陡黄土边坡为工程背景,应用所得理论方法对其进行风险定量分析,计算得出该边坡失稳概率为0.64,造成经济损失约8611万元,隶属于高风险等级,并针对坡体几何特征、渗透能力、基岩特性等低分指标提出了具体的安全性提升措施建议。 展开更多
关键词 重载铁路 风险分析 层次分析法 SIGMOID函数 经济损失
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磷指数模型在美国的应用和发展
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作者 马华 雷秋良 +6 位作者 杜新忠 赵营 李影 安妙颖 武淑霞 樊秉乾 刘宏斌 《农业环境科学学报》 CAS CSCD 北大核心 2024年第5期965-973,共9页
磷是植物生长必需的营养元素之一,在农业生产中起着关键作用。然而,长期过量的磷肥投入导致土壤磷素水平增加,进而加大了土壤磷素流失风险,造成农业非点源磷污染,同时这也成为导致水体富营养化的主要因素之一。因此,识别和管理农业非点... 磷是植物生长必需的营养元素之一,在农业生产中起着关键作用。然而,长期过量的磷肥投入导致土壤磷素水平增加,进而加大了土壤磷素流失风险,造成农业非点源磷污染,同时这也成为导致水体富营养化的主要因素之一。因此,识别和管理农业非点源磷的流失风险关键区,成为面源污染亟待解决的关键问题。磷指数模型起源于20世纪90年代,是评估农田磷流失潜力和指导磷管理决策的重要工具之一。根据研究区特点,美国众多学者在各州设立了不同的磷指数指标体系,优化了磷指数的组成因子、计算方法和分级标准。本文对美国各州磷指数模型评价体系进行了综述和评价,指出了磷指数模型的局限性,提出了改进方向,以期为我国磷素管理方法提供借鉴。 展开更多
关键词 磷指数 非点源污染 磷素迁移 评价体系 流失风险
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坡位与利用方式对红壤磷素储存容量的影响差异——以江西鹰潭孙家小流域为例
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作者 郑奕 王艳玲 刘卓玲 《农业环境科学学报》 CAS CSCD 北大核心 2024年第3期636-643,共8页
为明确坡位与利用方式对土壤磷素储存容量(SPSC)的影响差异,以更加准确地评估坡耕地红壤磷的流失风险,本研究以江西鹰潭孙家小流域内不同坡位(坡顶、坡上、坡中、坡底)及不同利用方式(稻田、花生旱地、橘园)的表层土壤为研究对象,对比... 为明确坡位与利用方式对土壤磷素储存容量(SPSC)的影响差异,以更加准确地评估坡耕地红壤磷的流失风险,本研究以江西鹰潭孙家小流域内不同坡位(坡顶、坡上、坡中、坡底)及不同利用方式(稻田、花生旱地、橘园)的表层土壤为研究对象,对比分析了SPSC的变化规律与差异,探讨了土壤全碳、全氮、全磷、有效磷、铁铝氧化物含量等因子对SPSC的影响。结果表明:不同坡位的稻田、花生旱地与橘园的SPSC变化范围分别为-410.9~-137.8、-283.8~-128.0 mg·kg^(-1)及-280.6~-36.3 mg·kg^(-1);且随坡位的降低,稻田(坡底除外)与橘园SPSC显著降低,而花生旱地SPSC则增加。与稻田土壤相比,同一坡位花生旱地与橘园SPSC相对增加;相关分析表明,不同坡位的稻田、花生旱地及橘园SPSC与土壤非晶质铁铝氧化物、游离态铁铝氧化物极显著正相关,且游离态氧化铝的影响相对最大,而与有效磷、总碳、总氮则显著负相关。江西鹰潭孙家小流域内红壤坡耕地SPSC均为负值,意味着此时的土壤均为磷源,土壤磷均具有流失风险;坡底的稻田及橘园、坡顶花生旱地土壤磷的流失风险相对较高,应及时采取相应的调控措施以有效降低土壤磷素的流失潜能与风险。 展开更多
关键词 红壤坡耕地 土壤磷储存容量 利用方式 磷流失风险 孙家小流域
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非肥胖2型糖尿病患者肌肉量减少危险因素的列线图预测模型研究
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作者 张冰青 胡馨云 +3 位作者 欧阳煜钦 向心月 汤文娟 冯文焕 《中国全科医学》 CAS 北大核心 2024年第33期4139-4146,共8页
背景肌肉量减少能增加2型糖尿病(T2DM)患者高血糖及肌少症发生风险,中国成人T2DM以非肥胖者为主,这些患者较肥胖者更容易伴发肌肉量减少。目的建立个体化预测非肥胖T2DM患者肌肉量减少危险因素列线图预测模型。方法回顾性选取2018年1月... 背景肌肉量减少能增加2型糖尿病(T2DM)患者高血糖及肌少症发生风险,中国成人T2DM以非肥胖者为主,这些患者较肥胖者更容易伴发肌肉量减少。目的建立个体化预测非肥胖T2DM患者肌肉量减少危险因素列线图预测模型。方法回顾性选取2018年1月—2023年9月南京大学医学院附属鼓楼医院内分泌科收治的非肥胖T2DM患者905例为研究对象,以简单随机抽样法按7∶3比例分为训练集(633例)和验证集(272例),收集两组患者的一般资料及临床指标并进行比较。根据多因素Logistic回归分析确定训练集肌肉量减少风险影响因素并构建列线图预测模型,采用受试者工作特征(ROC)曲线、Hosmer-Lemeshow校准曲线及临床决策曲线(DCA)评估列线图预测模型的预测价值和临床实用性。结果非肥胖T2DM患者肌肉量减少的患病率为42.3%(383/905)。训练集和验证集患者各项临床指标比较,差异均无统计学意义(P>0.05)。多因素Logistic回归分析结果显示,增龄(OR=1.039,95%CI=1.010~1.070,P=0.009)、男性(OR=3.425,95%CI=2.133~5.499,P<0.001)、BMI<23.5 kg/m^(2)(OR=19.678,95%CI=11.319~34.210,P<0.001)、糖化血红蛋白升高(OR=1.196,95%CI=1.081~1.323,P<0.001)、内脏脂肪面积增加(OR=1.021,95%CI=1.010~1.032,P<0.001)是非肥胖T2DM患者肌肉量减少的独立危险因素。列线图预测模型预测训练集和验证集患者肌肉量减少发生风险的ROC曲线下面积(AUC)分别为0.825(95%CI=0.793~0.856,P<0.001)和0.806(95%CI=0.753~0.859,P<0.001)。Hosmer-Lemeshow拟合优度检验结果显示,拟合度较好(训练集:χ^(2)=11.822,P=0.159;验证集:χ^(2)=8.189,P=0.415)。Bootstrap法绘制模型校准图显示校准曲线与标准曲线贴合良好。DCA曲线显示当患者阈值概率为0.06~0.94时,使用列线图预测模型预测T2DM患者发生肌肉量减少的发生风险更有益。结论增龄、男性、BMI<23.5 kg/m^(2)、糖化血红蛋白升高、内脏脂肪面积增加是非肥胖T2DM患者肌肉量减少的独立危险因素。本研究构建的列线图预测模型可个体化预测非肥胖T2DM患者伴发肌肉量减少风险,便于早期识别高危人群,利于制订个体化干预措施。 展开更多
关键词 糖尿病 2型 非肥胖 肌肉量减少 列线图 危险因素
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