臭氧(O3)与甲烷(CH4)均是大气中重要的微量气体,对全球气候变化有着重要的影响.为提高全球范围的臭氧、甲烷在气候模式中的预报效果,使用集合平方根滤波(En SRF)同化方法及地球系统模式(CESM)构建了CESM-En SRF卫星资料同化预报系统,并通过设计试验,将大气红外探测器(AIRS)的臭氧与甲烷观测资料同化到气候模式中,对模式的同化再预报效果进行系统的测试与评估.结果显示,臭氧、甲烷分析集合均值的偏差及均方根误差皆低于背景集合均值的偏差及均方根误差.臭氧、甲烷的同化再预报偏差及均方根误差较控制实验都得到改善,但对5 h Pa以上高度臭氧预报准确性的改进效果很小.随循环同化的进行,平流层臭氧与甲烷的平均同化改进率呈增加趋势,并逐渐趋于稳定;对流层平均同化改进率随时间变化不明显.试验表明,该系统可有效利用臭氧与甲烷的观测资料对模式场进行合理的改善,从而有效地提高臭氧、甲烷在气候模式中的再预报效果,但对于平流层顶-中间层高度(5 h Pa以上)臭氧预报准确度的提高,模式中臭氧光化学过程的准确模拟较同化观测资料具有更重要的作用.此外,循环同化对提高5~150 h Pa高度臭氧及1~200 h Pa高度甲烷在CESM模式中的预报效果最有效. 相似文献
考察了电流密度、pH值、曝气量、电解质Na_2SO_4浓度等工艺条件对活性炭纤维(ACF)阴极产生H_2O_2的影响规律。通过测定N_2吸附-脱附等温线和扫描电子显微镜(SEM)等手段观察了ACF的微观结构,从微观结构角度探讨了ACF阴极产生的优势与机理。结果表明,ACF孔隙结构丰富,比表面积大,有利于氧气分子在电极表面及孔道内的吸附-还原过程。当电流密度为5 m A/cm~2,pH=3,曝气量400 m L/min,电解质Na_2SO_4浓度为0.05 mol/L时,电解180 min还原产生H_2O_2的质量浓度高达27.86 mg/L。 相似文献
Objective: Road accidents are an important public health concern, and speeding is a major contributor. Although flow theory (FLT) is a valid model for understanding behavior, currently the nature of the roles and interplay of FLT constructs within the theory of planned behavior (TPB) framework when attempting to explain the determinants of motivations for intention to speed and speeding behavior of car drivers is not yet known. The study aims to synthesize TPB and FLT in explaining drivers of advanced vehicles intentions to speed and speed violation behaviors and evaluate factors that are critical for explaining intention and behavior.
Method: The hypothesized model was validated using a sample collected from 354 fully licensed drivers of advanced vehicles, involving 278 males and 76 females on 2 occasions separated by a 3-month interval. During the first of the 2 occasions, participants completed questionnaire measures of TPB and FLT variables. Three months later, participants' speed violation behaviors were assessed.
Results: The study observed a significant positive relationship between the constructs. The proposed model accounted for 51 and 45% of the variance in intention to speed and speed violation behavior, respectively. The independent predictors of intention were enjoyment, attitude, and subjective norm. The independent predictors of speed violation behavior were enjoyment, concentration, intention, and perceived behavioral control.
Conclusions: The findings suggest that safety interventions for preventing speed violation behaviors should be aimed at underlying beliefs influencing the speeding behaviors of drivers of advanced vehicles. Furthermore, perceived enjoyment is of equal importance to driver's intention, influencing speed violation behavior. 相似文献