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271.
高速公路交通事故分析及预防对策研究 总被引:20,自引:8,他引:12
利用济青高速公路 1998~ 1999年发生的 10 85起交通事故数据 ,在资料收集、处理和统计分析的基础上 ,对影响高速公路交通事故的人、车辆、道路环境、天气和交通量等主要因素进行了分析 ,并与国外的统计结果进行对比研究 ,预测出随着高速公路交通量的增长 ,事故率将会增加。此外 ,笔者针对影响高速公路事故因素提出了主动性、被动性预防对策 ,这些对策的实施将会减少高速公路事故的发生 相似文献
272.
Samura Alusine Al-Agha Omar Tuncel Semra G. 《Water, Air, & Soil Pollution: Focus》2003,3(5-6):111-129
The concentrations of heavy, trace elements and major ions measuredin the Uluda and Bursa aerosols were investigated to assess size distributions, spatial and temporal variability, sources and source regions affecting the composition of aerosols in Uluda and Bursa. A total of 81 samples were collected in two sites, one in Bursa city and another in the Uluda Mountain during two sampling campaigns. Daily samples were collected using a high volume sampler on Whatman 41 cellulose filters in Uluda, while three days interval samples were collected in Bursa using an automatic dichotomous sampler on PTFE Teflon filters. Samples were analysed for 15 trace and heavy metals (Al, Fe, Ba, Na, Mg, K, Mn, Ca, Cu), (V, Pb, Cd, Cr, Ni, Zn), and 4 major ions (SO4
2-, NO3
-, Cl-), (NH4
+) using ICP-AES, GFAAS, HPLC and UV/VIS Spectrophotometer,respectively. In general, concentrations of the metals measured inUluda aerosols were lower than those in Bursa. The concentrations of crustal elements were higher in summer than winter, while anthropogenic elements had higher concentrations in winter than summer. Most of the mass of crustal elements was concentrated in the coarse mode while the mass of the heavy metals was concentrated in the fine mode. Factor analysis revealed four factors with sources including crustal, industrial and combustion. Back trajectory calculations were used to determine long range contributions. These calculations showed that contributions were mostly from European countries, former Soviet Union countries, Black Sea and North Africa. 相似文献
273.
A relative significance factor (f
i
) of an impact category is the external weight of the impact category. The objective of this study is to propose a systematic
and easy-to-use method for the determination of f
i
. Multiattribute decision-making (MADM) methods including the analytical hierarchy process (AHP), the rank-order centroid
method, and the fuzzy method were evaluated for this purpose. The results and practical aspects of using the three methods
are compared. Each method shows the same trend, with minor differences in the value of f
i
. Thus, all three methods can be applied to the determination of f
i
. The rank order centroid method reduces the number of pairwise comparisons by placing the alternatives in order, although
it has inherent weakness over the fuzzy method in expressing the degree of vagueness associated with assigning weights to
criteria and alternatives. The rank order centroid method is considered a practical method for the determination of f
i
because it is easier and simpler to use compared to the AHP and the fuzzy method. 相似文献
274.
Lam LT 《Journal of Safety Research》2002,33(3):411-419
PROBLEM: Motor-vehicle accidents are one of the major causes of injury in most motorized countries. Driver distractions have been suggested as a contributor to traffic accidents. Moreover, age of the driver seems to have a role in the relationship between distractions and car crashes. But very few studies have investigated the effect of driver's age on this relationship. This exploratory study investigated the association between distractions, both inside and outside the vehicle, and the increased risk of car crash injury among drivers across different ages. METHOD: This study used a case series design to analyze data routinely collected by the NSW police in Australia. A special focus of this study was on how drivers' age affects the risk of car crash injury, which was determined by using a well-documented risk estimation methodology. RESULTS: The results obtained indicated that drivers of all ages, on the whole, are more susceptible to distractions inside the vehicle than distractions coming from outside. Age was shown to affect the relationship between in-vehicle distraction and the risk of car crash injury. A separate analysis was also conducted on hand-held phone usage while driving with results supplementing previous findings reported in the literature. IMPACT TO INDUSTRY: Safety strategies to countermeasure in-vehicle distractions have been suggested and discussed. 相似文献
275.
276.
Anjana Pant 《The Environmentalist》2000,20(4):295-300
Nostoc calcicola cells exposed to mercuric chloride (0.05–0.25 M), methyl mercuric chloride (0.05–0.15 M) and the fungicide ceresan (phenyl mercuric acetate; 0.05–0.20 M) showed sensitivity in the sequence: methyl mercury3) over phenyl mercuric acetate (0.51×103); inorganic mercury occupied the intermediate position with a bioconcentration factor of 1.32×103. The data infer that larger molecules of organomercurials may not be taken up by cells at the rate and extent comparable to the smaller species. 相似文献
277.
利用格子Boltzmann方法,对一维粘性泥石流的运动进行了定量化研究和数值模拟,为进一步研究泥石流的运动机制奠定了基础。在模拟一维粘性泥石流运动时,采用了含外力项的格子Boltzmann模型,通过对外力因子、平衡态分布函数的构造,使得宏观统计特性刻画了泥石流运动的非线性特征,成功模拟了泥石流的运动过程,获得了泥石流水深、流速两大要素的时空变化规律,为研究泥石流运动过程提供了一种新手段。 相似文献
278.
可拓法评估煤矿瓦斯爆炸易发性 总被引:3,自引:0,他引:3
为了量化煤矿瓦斯爆炸的可能性,并为防治瓦斯爆炸提供量化指标,借鉴可拓学原理,对煤矿瓦斯爆炸易发性进行预评估。首先,详细阐述可拓学评估原理;接着,为了验证煤矿瓦斯爆炸易发性可拓评估的可行性,结合某一煤矿实例,比选煤矿瓦斯爆炸易发性的评价指标,并确定煤矿瓦斯爆炸易发性的分类标准,构建煤矿瓦斯爆炸易发性评估的经典域、节域和物元;然后,为了避免确定指标权重的人为主观因素的影响,提出用简单关联函数确定指标权重;最后,计算煤矿瓦斯爆炸易发性的关联函数值和关联度,确定瓦斯爆炸易发性的等级及其变量特征值。经计算,煤矿爆炸易发性的可拓评估结果为"很小"等级。同时,为了验证可拓评估结果的合理性,将其与模糊评估进行比较,两者所得评估结果相一致。从而表明:将可拓学应用于煤矿瓦斯爆炸易发性评估是合理可行的。 相似文献
279.
基于优势隐含周期分析的气象灾害预报 总被引:1,自引:0,他引:1
建立了优势因子和优势隐含周期的概念,并提出了多因子逐步回归周期分析的新方法。该方法既能增长预报期,又能充分利用物理因子的重要信息,同时在计算过程中还能挑选出起显著作用的优势因子和优势隐含周期,对预报气象要素的变化趋势效果较好,有一定的实用价值,是气象灾害预报的一条比较有效的途径。 相似文献
280.