Estimated daily intake of plasticizers in 1-week duplicate diet samples following regulation of DEHP-containing PVC gloves in Japan

Duplicate hospital diet samples obtained over 1 week in 2001 were analysed to estimate the daily intake of plasticizers and the results were compared with those obtained in 1999. The plasticizers quantified in this study were: dibutyl phthalate, butylbenzyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), di(2-ethylhexyl) adipate (DEHA), diisononyl adipate (DINA) and O-acetyl tributyl citrate (ATBC). Dipropyl, dipentyl, dihexyl and dicyclohexyl phthalate were also analysed but not detected. The analytical procedure for this follow-up study was essentially the same as in the previous one. Detection limits were 0.1-15.6 ng g^-1 for each plasticizer. One-week duplicate diet samples provided by three hospitals in three remote prefectures of Japan were analysed as individual meals. DEHP was detected at 6-675 ng g^-1 in 62 of 63 meals, significantly lower levels compared with those detected in 1999. Levels of DEHA and DINP also decreased. The mean intake of plasticizers estimated from all samples was 160 μg DEHP day^-1, 12.5 μg DEHA day^-1, 4.7 μg DINP day^-1 and 3.4 μg BBP day^-1. Levels of DINA were relatively high in meals from one hospital: in those meals, the average daily intake was 1338 μg day^-1. Those of ATBC were also higher in meals from another hospital: the average daily intake was 1228 μg day^-1. The sources of DINA and ATBC can be cling-film or sausage packaging.     

氚化水摄入量—尿氚浓度换算因子的估算

对10名氘化水摄入者的观察结果表明,单位摄入量所致的体内氚滞留量R~I(t)可用两项指数函数之和来描述,即R~I(t)=0.987exp(-0.693(t/10))+0.013exp(-0.693(t/42))。假定人的体水体积为42L,体水氚浓度与尿氚浓度相同,则可推导出摄入量-尿氚浓度换算因子c_u~I(单位摄入量所致的尿氚浓度,以下简称摄入量换算因子),即c_u~I=[0.987exp(-0.693(t/10))+0.013exp(-0.693(t/42))]/42。在摄入后早期,上式给出的摄入量换算因子与ICRP第54号出版物给出的换算因子是一致的。但随着摄入后时间的推移,二者之间的差异将越来越明显,在摄入后第100天,前者较后者高约3.5倍,第200天时高约500倍。因此,在缺乏摄入后早期(约40天)的尿氚监测资料情况下,采用两个指数项之和的滞留函数来估算摄入量更为合适。     

吸入短寿命氨子体有效剂量当量的计算及ALI和DAC的导出

本文介绍了用于估算吸入短寿命氡子体所致肺组织剂量的肺剂量学模型,并给出有效剂量当量的计算及ALI和DAC的导出方法。     

进气道喷甲醇对柴油机性能及排放影响的研究

在增压柴油机的进气道上加装甲醇喷射系统,研究不同甲醇喷射比例对柴油机性能和排放的影响.结果表明,用甲醇替代部分柴油,在外特性试验中,甲醇的喷入扩展了发动机扭矩和功率范围,最大升高幅值分别为12.1％和12.0％.同时,柴油的消耗率降低,最大降幅为22.6％,使用经济性有所改善,费用支出率最高降幅为15.2％,但高转速高负荷时费用支出率升高了4.4％.进气道喷甲醇有效抑制了NOx的排放,最高降幅达到84.5％,碳烟的排放升高.     

电控汽油机进气管长度连续可变系统

通过分析、设计、计算，研制了一种进气管长度连续可变系统，使得赛车发动机在不同的工作转速均有较高的扭矩。     

Assessment of Slovak population exposure to cadmium from food

Exposure of the Slovak Republic population to cadmium from food and drinks was studied. Calculations were done by means of 1,66,312 food, plant and animal raw materials and drinks sampled within systematic inspection and monitoring of contaminants in 1990–2003. Exposure assessment of average inhabitants to cadmium from actual and model consumption patterns were calculated and compared with the provisional tolerable weekly intake (PTWI) value. Considering the model consumption, the exposure doses were assessed also for selected demographic groups. The assessed exposure of the population to cadmium has been persistently low with a moderately decreasing tendency especially for the past few years. The assessed real weekly exposure doses of cadmium from foodstuffs and beverages in the last 5 years while using the mean values and median values were 20–14.8% PTWI and 12.6–7.6% PTWI, respectively.     

SUV车型机舱冷却性能仿真分析与优化

针对某SUV车型中低速爬坡工况时发动机水温偏高问题,应用一维与三维联合仿真方法对车辆进行数值仿真分析,并对仿真的精准性进行试验验证.通过建立三维整车模型,对机舱进行冷流场计算,结合一维仿真发现发动机出水温度偏高,未能满足设计要求.对机舱内流场进行分析,发现冷却模块前端进气通道存在明显涡流、流动死区的现象.提出调整格栅开...     

四气门天然气发动机缸内瞬态流场数值模拟

采用K-ε双方程模型对四气门天然气发动机进气道及缸内的瞬态流场进行数值模拟,模拟了发动机进气、压缩及燃烧过程。结果表明：四气门发动机缸内涡流由外向内形成;缸内平均湍动能强度在进气冲程中总体呈先增大后减小的趋势,压缩冲程中耗散作用使湍动能降低,但挤流作用使气缸中部的湍动能升高;进气过程中存在流动分层,为改善小负荷时发动机性能,天然气应尽可能在进气冲程中、后期进入气缸;缸内涡流中心的位置和气流速度梯度对火焰径向传播的均匀性有很大影响。