基于回归分析的群集疏散时间模型优化研究

为提高国际上通用的疏散时间模型(简称经验模型)的仿真度,将人员的属性因素(自然属性和社会属性)影响纳入时间模型,采用回归分析方法,以某高校大型大学生艺术中心疏散案例为研究基础,通过调查采样建立185组数据的实测样本。结合影响人员疏散行为和疏散时间相关因素,运用统计软件SPSS17.0对样本进行回归分析,建立疏散时间回归模型。以回归模型为基础,将个体属性综合为群集属性,求取修正系数并对经验模型进行修正、检验。结果表明:利用回归分析和修正系数对疏散时间经验模型进行修正,可有效弥补经验模型缺乏考虑群集属性影响的弱点,提高经验模型的仿真度和应用价值。     

热水介质＋脱附破乳组剂处理高凝固点油泥的条件研究

通过热水介质添加脱附破乳组剂的方法,研究了辽河油田公司沈阳采油厂油泥分离的相关条件。通过油泥的组分分析、热水介质温度实验、处理时间实验、脱附破乳组剂浓度实验,确定了热水介质添加脱附破乳组剂实现油泥分离的条件:脱附破乳组剂浓度为15.0 g/L、洗涤温度50℃、洗涤时间大于5 min。     

中国主要客源地进出口贸易与入境旅游发展关系的研究

基于1995—2008年统计数据,从洲际和客源国两个层面入手,分析客源地进出口贸易总额和入境客流总量的关系,选取1995—2008年我国同各洲(国)的进出口贸易和入境客流量的案板数据,建立入境客流量和进出口贸易总额的统计方程,分析两者间的相互关系。同时,分析了贸易市场占有率和客源市场占有率的关系,选取1995—2008年对外贸易和入境旅游的相关数据,计算出各洲(国)贸易和客源的市场占有率,分析其变化规律。     

Trends in Pesticide Concentrations in Streamsof the Western United States, 1993‐20051

Johnson, Henry M., Joseph L. Domagalski, and Dina K. Saleh, 2010. Trends in Pesticide Concentrations in Streams of the Western United States, 1993‐2005. Journal of the American Water Resources Association (JAWRA) 00(0):1‐22. DOI: 10.1111/j.1752‐1688.2010.00507.x Abstract: Trends in pesticide concentrations for 15 streams in California, Oregon, Washington, and Idaho were determined for the organophosphate insecticides chlorpyrifos and diazinon and the herbicides atrazine, s‐ethyl diproplythiocarbamate (EPTC), metolachlor, simazine, and trifluralin. A parametric regression model was used to account for flow, seasonality, and antecedent hydrologic conditions and thereby estimate trends in pesticide concentrations in streams arising from changes in use amount and application method in their associated catchments. Decreasing trends most often were observed for diazinon, and reflect the shift to alternative pesticides by farmers, commercial applicators, and homeowners because of use restrictions and product cancelation. Consistent trends were observed for several herbicides, including upward trends in simazine at urban‐influenced sites from 2000 to 2005, and downward trends in atrazine and EPTC at agricultural sites from the mid‐1990s to 2005. The model provided additional information about pesticide occurrence and transport in the modeled streams. Two examples are presented and briefly discussed: (1) timing of peak concentrations for individual compounds varied greatly across this geographic gradient because of different application periods and the effects of local rain patterns, irrigation, and soil drainage and (2) reconstructions of continuous diazinon concentrations at sites in California are used to evaluate compliance with total maximum daily load targets.     

Impacts of Land‐Cover Change on Suspended Sediment Transport in Two Agricultural Watersheds1

Schilling, Keith E., Thomas M. Isenhart, Jason A. Palmer, Calvin F. Wolter, and Jean Spooner, 2011. Impacts of Land‐Cover Change on Suspended Sediment Transport in Two Agricultural Watersheds. Journal of the American Water Resources Association (JAWRA) 47(4):672‐686. DOI: 10.1111/j.1752‐1688.2011.00533.x Abstract: Suspended sediment is a major water quality problem, yet few monitoring studies have been of sufficient scale and duration to assess the effectiveness of land‐use change or conservation practice implementation at a watershed scale. Daily discharge and suspended sediment export from two 5,000‐ha watersheds in central Iowa were monitored over a 10‐year period (water years 1996‐2005). In Walnut Creek watershed, a large portion of land was converted from row crop to native prairie, whereas in Squaw Creek land use remained predominantly row crop agriculture. Suspended sediment loads were similar in both watersheds, exhibiting flashy behavior typical of incised channels. Modeling suggested that expected total soil erosion in Walnut Creek should have been reduced 46% relative to Squaw Creek due to changes in land use, yet measured suspended sediment loads showed no significant differences. Stream mapping indicated that Walnut Creek had three times more eroding streambank lengths than did Squaw Creek suggesting that streambank erosion dominated sediment sources in Walnut Creek and sheet and rill sources dominated sediment sources in Squaw Creek. Our results demonstrate that an accounting of all sources of sediment erosion and delivery is needed to characterize sediment reductions in watershed projects combined with long‐term, intensive monitoring and modeling to account for possible lag times in the manifestation of the benefits of conservation practices on water quality.     

沙尘暴变化的时空特征——基于站日和站时数据的对比分析

利用中国强沙尘暴序列及其支撑数据集,分别以站日和站时为计算单位,建立了中国50 a(1958-2007年)沙尘暴时间序列,分析了两个序列的关系,并比较了两者所反映出的沙尘暴时空变化特征。结果表明,站日和站时序列总体变化趋势比较一致,但细节有所差别,有时会影响某些结论。在反映沙尘暴的时间变化和空间分布时,两者存在明显的差异。     

大跨径钢管混凝土拱桥减震控制装置参数的研究

大跨度桥梁结构的减震控制研究对于桥梁结构的抗震安全具有重要意义。本文以主跨368m的茅草街大桥为研究对象,基于ANSYS建立了该桥的三维有限元模型,并采用子空间迭代法分析了该桥的动力特性。在此基础上进行了大跨度钢管混凝土拱桥的地震响应及减震控制研究,重点进行了弹性连接装置和粘滞阻尼器减震效果的参数敏感性分析,并对比分析了不同位置布设减震装置时的效果。结果表明,纵飘振型对该桥肋纵向相对位移的贡献最大;弹性连接装置和阻尼器均能有效减小地震作用下该桥的肋梁纵向相对位移;综合考虑各关键部位的地震响应时,同时采用两类减震装置并将其分散布置时的减震效果最佳。结论可供大跨度中承式钢管混凝土系杆拱桥的抗震设计参考。     

异戊二烯和甲苯二次有机示踪物的臭氧非均相氧化

本文基于相对速率法,通过烟雾箱实验测定了异戊二烯和甲苯二次有机示踪物的臭氧非均相氧化的有效速率常数,考察了不同条件(相对湿度和混合状态等)对示踪物臭氧非均相氧化过程的影响,并且分析了由于示踪物被氧化所引起的二次源解析的不确定性.结果表明,赤藓糖醇(analogue of 2-methyl erythritol,AME)和2,3-二羟基-4-氧代戊酸(2,3-dihydroxy-4-oxopentanoic acid,DHOPA)的有效速率常数分别为(4. 60±0. 66)×10-19cm~3·(molecule·s)~(-1)和(6. 57±0. 51)×10-19cm~3·(molecule·s)~(-1);考虑到示踪物不稳定引起的不确定性,采用示踪物产率法解析二次源会对异戊二烯和甲苯二次生成气溶胶低估约16. 5%～44. 8%和18. 3%～47. 3%.     

基于多需求点的震灾应急物资调度模型研究

为了解决震后应急物资调度中,因不考虑各应急需求点灾情差异和需求差异带来的决策结果不够合理的问题,采用改进的专家打分法将收集到的灾情信息量化为灾情因子,在此基础上建立应急成本和应急延误时间的多目标模型。采用逐步法求解,为每一个应急需求点确定提供应急物资的供应点及供应量。将此方法运用到云南发生的某地震灾后救援中,计算得出与3个应急需求点对应的应急供应点及其供应量。     

A Heart Rate Evaluation Approach to Determine Cost-Effectiveness an Ergonomics Intervention

This paper describes a hear-rate methodology to determine the cost-effectiveness of an ergonomics intervention to reduce workload and improve working conditions. This is a practical approach as opposed to the energy expenditure technique that is difficult to implement in natural settings. This was a laboratory study using a large excavator cabin with devices to simulate excavation operations. Mean heart rate was used to calculate the required rest time during a shift with or without air-conditioning. The criterion for evaluation was differences in required rest time during a shift under these 2 conditions. The simplicity and objectivity of this approach invites use to solve the problem of the economic evaluation of ergonomics interventions.