防毒面具用活性炭的结构与特性研究

从研究活性炭所具有的孔隙结构出发,重点探讨防毒面具用活性炭的结构与防护性能的关系,明确了不同结构特性的活性炭对不同类型有毒气体防护机理与性能的差异,为科学选择防毒面具用活性炭提供了重要依据。文章还对体现活性炭孔隙结构的主要指标——孔容积的计算方法进行了探讨。     

活性炭对水中重金属离子去除效果的研究

通过静态吸附试验和吸附热力学与吸附机理探讨,表明pH值和活性炭投加量是影响活性炭从水中吸附重金属的主要因素,吸附容量随pH值增大而增大,但却随着吸附剂投加量的增加而减少;吸附规律可用Freundlich模式和Lang muir模式很好的模拟,重金属的吸附能力大小是Fe3 + >Cu2 + >Ni2 +     

The role of off-path glances: A quantitative analysis of rear-end conflicts involving Chinese professional truck drivers as the striking partners

Introduction: Rear-end crashes are one of the most frequent crash types in China, leading to significant economic and societal losses. The development of active safety systems – such as Automatic Emergency Braking System (AEBS) – could avoid or mitigate the consequences of these crashes in Chinese traffic situations. However, a clear understanding of the crash causation mechanisms is necessary for the design of these systems. Method: Manually coded variables were extracted from a naturalistic driving study conducted with commercial vehicles in Shanghai. Quantitative analyses of rear-end crashes and near crashes (CNC) were conducted to assess the prevalence, duration, and location of drivers’ off-path glances, the influence of lead vehicle brake lights on drivers’ last off-path glance, and driver brake onset, and the influence of off-path glances and kinematic criticality on drivers’ response to conflicts. Results: The results indicate that the Chinese truck drivers in our study rarely engage in distracting activities involving a phone or other handheld objects while driving. Instead, they direct their off-path glances mainly toward the mirrors, and the duration of off-path glances leading to critical situations are shorter compared to earlier analyses performed in Western countries. The drivers also often keep small margins. Conclusions: Overall, the combination of short time headway with off-path glances directed toward the mirror originates visual mismatches which, associated to a rapid change in the kinematic situation, cause the occurrence of rear-end CNC. When drivers look back toward the road after an off-path glance, a fast response seems to be triggered by lower values of looming compared to previous studies, possibly because of the short time headways. Practical Application: The results have practical implications for the development of driver models, for the design of active safety systems and automated driving, and for the design of campaigns promoting safe driving.     

Performance study on evacuated tubular collector coupled solar still in West Texas climate

Experimental study was performed on a single basin active solar distillation system augmented with a solar collector using evacuated solar tubes. Field tests were conducted over several days under the climatic conditions of West Texas to evaluate the effect evacuated solar tubes have on the daily distillate yield rate. To investigate the feasibility of the solar tubes, active and passive solar stills with and without exterior insulation were examined. The maximum daily production rate for the active distillation system using evacuated solar tubes and the passive distillation system was 3.6 and 1.4 kg/m²day, respectively. The results showed the augmentation of the still with evacuated solar tubes increased its production capacity by a factor of 2.63. It also increased the maximum temperature of the water in the still basin by at least 20 °C. Economic analysis shows that it is feasible to use evacuated tubular collector coupled solar still as an alternative means for reclaiming water in farmlands with a payback period of approximately 6 years.     

KJF-01型室内空气净化器的实验研究

将高压静电场除尘杀菌、活性炭吸附光催化分解等技术集成一体 , 开发高效空气净化技术和空气净化器,并进行污染物净化实验。结果表明,该集成技术对空气中颗粒物、二甲苯和甲醛等污染物均具有很高的净化效率;气态污染物净化时,初期以活性炭吸附为主,后期以光催化分解为主;活性炭吸附具有选择性,吸附二甲苯速度比甲醛快。     

AEB effectiveness evaluation based on car-to-cyclist accident reconstructions using video of drive recorder

Objective: Though autonomous emergency braking (AEB) systems for car-to-cyclist collisions have been under development, an estimate of the benefit of AEB systems based on an analysis of accident data is needed for further enhancing their development. Compared to the data available from in-depth accident data files, data provided by drive recorders can be used to reconstruct car-to-cyclist collisions with greater accuracy because the position of cyclists can be observed from the videos. In this study, using data from drive recorders, the performance and limitations of AEB systems were investigated.

Method: Data of drive recorders involving taxi-to-cyclist collisions were collected. Using the images collected from the drive recorders of those taxis, 40 cases of 90° car-to-cyclist intersection collisions were reconstructed using PC-Crash. Then, the collisions were reconstructed again utilizing car models with AEB systems installed while changing the sensor’s field of view (FOV) and the delay time of initiating vehicle deceleration.

Results: The angle of FOV has a significant influence on avoiding car-to-cyclist collisions. Using a 50° FOV with a braking delay time of 0.5?s resulted in avoiding 6 collisions, and using a 90° FOV resulted in avoiding an additional 14 collisions. Even when installing an ideal AEB system providing 360° FOV and no delay time for braking, 8 collisions were not avoided, though the impact velocities were reduced for all of these remaining collisions. These collisions were caused by the cyclists’ sudden appearance in front of cars, and the time-to-collision (TTC) when the cyclists appeared was less than 0.9?s.

Conclusion: The AEB systems were effective for mitigating collisions that occurred due to driver perception delay. Because cyclists have a traveling velocity, a wide-angle FOV is effective for reduction of car-to-cyclist intersection collisions. The reduction of delay time in braking can reduce the number of collisions that are close to the braking performance limit. The collisions that remained even with an ideal AEB system in the PC-Crash simulation indicate that such collisions could still occur for autonomous cars if the traffic environment does not change.     

絮凝用聚合物最佳性能的探讨

本文通过对聚合物混凝剂活化的过程进行剖析，提出了水力条件是唯一影响因素，并比较了三类混合器的性能．     

铝阳极电凝聚处理活性红241动力学分析

在一个序批式反应器中,以铝作阳极、不锈钢作阴极,考察了电流密度、初始pH值、电解质浓度及种类、温度、染料浓度因素对电凝聚处理活性红241动力学过程的影响。结果表明,电凝聚处理活性红241遵循均一级动力学方程;电流强度、染料浓度、电解液初始pH值、氯化钠电解质浓度、温度对染料溶液脱色速率常数的影响显著,而硫酸钠电解质浓度则影响不明显;在电凝聚处理过程中,主要作用机理是以铝离子的单核水解产物与染料络合作用占主导地位。     

活性炭负载TiO_2光催化杀菌研究

研究了溶胶-凝胶法制备活性炭颗粒负载TiO2的光催化杀菌作用,探讨了光催化剂的最佳制备条件。实验结果表明,光催化杀菌效果明显好于单独紫外光的杀菌效果,当钛酸丁脂与无水乙醇比例为1:8制备TiO2溶胶,活性炭颗粒浸涂凝胶一次、在450℃煅烧2h,20min的杀菌率可达88%,在溶胶中掺杂Fe3+的杀菌率可达到95%,提高了活性炭负载TiO2的光催化活性。     

活性污泥PVA膜状固定及净化污水效率

PVA膜状固定细胞是一种新细胞固定化方法。在加入少量藻酸钙盐的条件下 ,用硼酸交联聚乙烯醇 ( PVA) ,活性污泥培养物渗于其内 ,将其涂于载体上被固定成膜。细胞经固定后仍保持活力 ,PVA—藻酸钙盐珠非常结实耐用。