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11.
为了解山西省城市居民对室内空气质量安全的认知情况和室内空气质量现状,在山西省太原、大同、晋城和吕梁随机选取786户居民进行问卷调查,并对有检测意愿的86户居民进行室内甲醛含量检测.结果表明,山西省居民室内空气质量安全认知得分15.37,得分率为51%;山西省居民平均室内甲醛浓度(0.197 mg/m3)超过国家标准(0.1 mg/m3);四市中太原市的情况最好.山西省居民在室内空气质量安全方面的认知水平和室内空气质量都不高,为保障山西省居民健康,应对山西省城市居民进行室内空气质量安全知识的普及.  相似文献   
12.
OH自由基与溴乙烷反应动力学和大气中存留寿命   总被引:2,自引:0,他引:2  
溴代烷烃是破坏臭氧层的重要物质,用放电流动-共振荧光技术,测定OH自由基与C2H5Br在297-369K温度范围的反应速率常数,求得其阿仑尼乌斯公式,并根据对流层的平均温度227K下求是OH自由基与溴乙烷反应速率常数(K)值,算出共在对流层的寿命为0.168a这将提供这类化合物使用否的重要科学根据。  相似文献   
13.
光离子检测器测定大气中溴甲烷   总被引:1,自引:0,他引:1  
用Tenax作为吸附剂捕集大气中的痕量溴甲烷,用气相色谱法和光离子检测器,对其进行检测,相对偏差为0.0521,最小检测限为10pg。室内外大气中的浓度分别为24×10(-12)(V/V)和77.4×10(-12)(V/V),污染在10(-11)(V/V)水平。  相似文献   
14.
测定了金钟藤(Merremia boisiana)枝条的生长速度,其枝条在生长季内平均每天长0.43-3-3cm,最快达7.8cm,且强枝能产生新的侧枝,营养生长能力强;调查了金钟藤始花期、开花数目、花期长短,并与其结实率进行相关性比较,发现金钟藤始花期和开花数目与结实率无显著相关性,而金钟藤花期长短与结实率呈显著负相关性(花期越长,结实率越低),且开花较多,但果实、种子极少,种子繁殖力低。  相似文献   
15.
Objective: To better capture the relationships between lane-changing collisions and explanatory variables, a microscopic model is developed for freeway lane-changing collisions based on the interactions between lane-changing vehicles.

Methods: The model applies an intervehicle interaction structure to account for the occurrence mechanism of lane-changing collisions. The occurrence mechanism can be described as the failure of a vehicle driver of an adjacent lane in avoiding the lane-changing vehicle, which disturbs the smooth movement of the adjacent lane vehicle and requires the driver's brake action to avoid an angle collision. This model is examined using data collected from freeways in Washington State during 2010 to 2011 and validated using lane-changing collision data for the SR 520 freeway.

Results: The findings of this study show that generalized truck percentage has a significant decreasing effect on lane-changing collision risk, whereas average spacing and several roadway characteristics have significant increasing effects. The frequency of slight collisions during peak hours is higher than that during off-peak hours. Young female drivers are more likely to be involved in collisions during lane-changing than young male drivers, but the result for senior drivers is opposite, with older male drivers having a higher probability of lane-changing collisions than female drivers in the same age group.

Conclusion: The process of lane-changing collisions is a complicated maneuver. Truck percentage, average spacing, and good roadway characteristics, such as straight and level segment, in the target lane have a significant effect on the occurrence of lane-changing collisions. Age and gender are also 2 important factors contributing to the relationship between lane-changing collisions and explanatory variables.  相似文献   

16.
北京市大气颗粒物中多环芳烃的组成   总被引:24,自引:2,他引:22  
采用高效液相色谱/质谱联用技术(HPLC/MS)检测了北京市石景山工业区和海淀居民生活区的大气颗粒物样品中的多环芳烃(PAHs),比较了北京市工业区和居民区大气飘尘中多环芳烃含量的差异以及不同季节对多环芳烃含量的影响.检测出PAHs类碳氢化合物共135种,分子质量大于300u的PAHs有55种,弥补了气相色谱/质谱(GC/MS)不能直接测定大分子量PAHs的不足,更为全面地反映了大气飘尘中PAHs的分布状况.  相似文献   
17.
模拟大气条件研究了HCFC-22+H2O2在有氧或无氧存在下用低压相进行辐照,在20m的长光程池中用富里叶红外光仪测量其化学产物,结果表明在没有氧情况下产物为COF2,CO2,HF和HCl;有氧存在时产物为CO2,H2O,HF和HCl。从这些产物推广其可能的光解机理。  相似文献   
18.
This study aims to analyze the effects of environment, vehicle and driver characteristics on the risky driving behavior at work zones. A decision tree is developed using the classification and regression tree (CART) algorithm to graphically display the relationship between the risky driving behavior and its influencing factors. This approach could avoid the inherent problems occurred in the conventional logistic regression models and further improve the model prediction accuracy. Based on the Michigan M-94/I-94/I-94BL/I-94BR highway work zone driving behavior data, the decision tree comprising 33 leaf nodes is built. Bad weather, poor road and light conditions, partial/no access control, no traffic control devices, turning left/right and driving in an old vehicle are found to be associated with the risky driving behavior at work zones. The middle-aged drivers, who are going straight ahead in their vehicles with medium service time and equipped with an airbag system, are more likely to take risky behavior at lower work zone speed limits. Further, the middle-aged male drivers engage in risky driving behavior more frequently than the middle-aged female drivers. The number of lanes exhibits opposing effects on risky behavior under different traveling conditions. More specifically, the risky driving behavior is associated with the single-lane road under bad light or weather conditions while drivers are more likely to engage in risky behavior on the multi-lane road under good light conditions.  相似文献   
19.
北京地区大气飘尘中检出潜在致癌物——硝基多环芳烃   总被引:6,自引:0,他引:6  
用两种方法(GC-MS法和还原-HPLC-荧光法)首次从北京大气飘尘中检出了数种硝基多环芳烃。虽然它们的含量低,但是由于其中例如1-硝基芘和3-硝基萤蒽系已知的动物致癌物,因此它们在环境中的存在值得注意。  相似文献   
20.
中国石化齐鲁分公司烯烃厂拥有3台燃油锅炉,主要为乙烯装置提供温度为510%、压力为11.5MPa的超高压蒸汽,燃料主要是焦油和重油。把添加剂加入燃料油后.可以加快燃料油的充分燃烧,减少废气排放,提高锅炉的热效率,从而达到节约能源及减少废气排放的目的,  相似文献   
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