华北工业城市夏季大气臭氧生成机制及减排策略

为了分析工业城市臭氧(O₃)污染的特征及形成机制,2021年6月在华北平原淄博市开展了综合观测,利用盒子模型(基于MCMv3.3.1化学机制)探究O₃前体物削减优化方案.结果表明：(1)O₃污染时期伴随静稳、高温低湿和强辐射等气象条件,含氧挥发性有机物(OVOC)和烯烃等人为源挥发性有机物(AVOC)组分对O₃生成潜势(OFP)和·OH反应速率(k_·OH)贡献率最大;(2)模型研究发现O₃主要受本地光化学生成和以输出性为主的区域传输影响,本地污染管控对降低O₃污染更为重要;(3)污染时期高浓度的·OH(10×10⁶ cm^-3)和HO₂·(14×10⁸ cm^-3)引发局地瞬时O₃生成速率高值(峰值36×10^-9 h^-1),HO₂·+NO和·O...     

Handgrip and Box Tilting Strategies in Handling: Effect on Stability and Trunk and Knee Efforts

The purpose of this study was to evaluate the effect of four handgrip/box tilting strategies (right, left, backward, and no tilt of the box) on trunk and knee efforts, body posture, and the stability of 14 participants with limited experience in handling. The tasks consisted of transferring a low-lying box placed in front of the participant to a shelf of the same height at the participant’s left. It was hypothesized that tilting the box could reduce trunk and knee efforts as well as body asymmetry and improve stability. A tridimensional dynamic rigid body model was used to estimate the triaxial net muscular moment magnitudes at the trunk (L5/SI) and at the knees. An approach to quantify the participants’ dynamic stability was also included. Finally, five angles were computed to characterize body asymmetries. The results showed that tilting the box affected specific trunk efforts, but did not succeed in reducing trunk asymmetric efforts. However, the tilts were executed in a single direction, and it may be possible that combined tilts of the box could help reduce trunk asymmetric efforts. Tilting the box had little effect on knee loadings, and the left tilt strategy reduced participants’ stability. This study showed the importance of considering the position of the box when assessing the risks encountered in asymmetrical handling.     

安钢2 200 m3高炉下阀箱卡料事故分析与处理

分析了安钢2200m^3高炉由于炉顶下阀箱内插入漏斗脱位引起卡料事故的原因及处理这起事故的难点,重点介绍了这起突发性事故的处理方法,总结了避免此类事故发生的方法。     

城市黑臭河道夏季产甲烷通量研究——以南宁市朝阳溪为例

利用静态箱法测定城市黑臭河道!南宁市朝阳溪夏季产甲烷通量,结果表明朝阳溪是重要的甲烷排放源,夏季甲烷排放通量平均值为12.2mg/(m2·h),上游、中游、下游排放通量变化不显著。利用偏最小二乘法进行相关性分析可得,甲烷通量与温度、化学需氧量、底泥有机碳呈显著正相关,与溶解氧呈显著负相关,与总氮、氨氮、总磷、pH相关性较小。     

Fate of linear alkylbenzenes and benzothiazoles of anthropogenic origin and their potential as environmental molecular markers in the Pearl River Delta, South China

The mass emissions of linear alkylbenzenes (LABs), benzothiazole (BT), and 2-[4-morpholinyl]benzothiazole (24MoBT) from anthropogenic activities within one year were estimated according to the population and the number of automobiles in the Pearl River Delta (PRD), South China. Based on the estimation, the distribution of these compounds among various environmental media was simulated with a mass balance box model established in the present study. The results showed that 79% of LABs generated in the PRD was stored in sediment while only 1.3% of LABs was presumably transported to the adjacent South China Sea (SCS). On the contrary, 47% of BT and 77% of 24MoBT generated in the region were carried with riverine runoff to the coastal ocean. The results from the present study suggest that hydrophobic compounds tend to stay in the watershed of the PRD, whereas hydrophilic ones mainly outflow to the coastal ocean.     

Biodegradation of imidacloprid in liquid media by an isolated wastewater fungus Aspergillus terreus YESM3

In the present study, a new fungal strain capable of imidacloprid degradation was isolated from agricultural wastewater drain. The fungal strain of YESM3 was identified as Aspergillus terreus based on ITS1-5.8S rDNA-ITS2 gene sequence by PCR amplification of a 500 bp sequence. Screening of A. terreus YESM3 to the insecticide imidacloprid tolerance was achieved by growing fungus in Czapek Dox agar for 6 days at 28°C. High values (1.13 and 0.94 cm cm^?1) of tolerance index (TI) were recorded at 25 and 50 mg L^?1 of imidacloprid, respectively in the presence and absence of sucrose. However, at 400 mg L^?1 the fungus did not grow. Effects of the imidacloprid concentration, pH, and inoculum size on the biodegradation percentage were tested using Box–Behnken statistical design and the biodegradation was monitored by HPLC analysis at different time intervals. Box–Behnken results indicated that optimal conditions for biodegradation were at pH 4 and two fungal discs (10 mm diameter) in the presence of 61.2 mg L^?1 of imidacloprid. A. terreus YESM3 strain was capable of degrading 85% of imidacloprid 25 mg L^?1 in Czapek Dox broth medium at pH 4 and 28°C for 6 days under static conditions. In addition, after 20 days of inoculation, biodegradation recorded 96.23% of 25 mg L^?1 imidacloprid. Degradation kinetics showed that the imidacloprid followed the first order kinetics with half-life (t₅₀) of 1.532 day. Intermediate product identified as 6-chloronicotinic acid (6CNA) as one of the major metabolites during degradation of imidacloprid by using HPLC. Thus, A. terreus YESM3 showed a potential to reduce pollution by pesticides and toxicity in the effected environment. However, further studies should be conducted to understand the biodegradation mechanism of this pesticide in liquid media.     

Removal of NAPLs from the unsaturated zone using steam: prevention of downward migration by injecting mixtures of steam and air

Steam injection for remediation of porous media contaminated by nonaqueous phase liquids has been shown to be a potentially efficient technology. There is, however, concern that the technique may lead to downward migration of separate phase contaminant. In this work, a modification of the steam injection technology is presented, where a mixture of steam and air was injected. In two-dimensional experiments with unsaturated porous medium contaminated with nonaqueous phase liquids, it was demonstrated how injection of pure steam lead to severe downward migration. Similar experiments, where steam and air were injected simultaneously, resulted in practically no downward migration and still rapid cleanup was achieved. The processes responsible for the prevention of downward migration when injecting steam-air mixtures were analyzed using a nonisothermal multiphase flow and transport model. Hereby, three mechanisms were identified and it was demonstrated how the effectiveness of these mechanisms depended on the air-to-steam mixing ratio.     

基于Event模型的冲突风险新算法

鉴于管制过程中对航空器冲突问题发展的研究,对经典事件模型的结构进行改进,用球形曲面间隔层代替传统的平面间隔层,结合扩展碰撞盒概率关系比计算冲突风险,提高了模板与实际航空器运行状态的切合度。并以模拟航空器飞行数据进行仿真,对改进模型的冲突风险与原模型的进行比较评估,结果表明该算法正确。     

雷击参数在线监录与SPD动态预警管理——“黑匣子”研究与应用

人类赖以生存的地球表面每小时约连续发生2000个雷暴。随着科学技术发展到如今的信息时代,任何场所(特别是雷电多发地区)都有可能发生雷击灾害,许多雷击事故往往是由于低压供、配电线路与信息传输线路感应传导雷电高电压引起的。尽管闪电定位系统得到了广泛的应用,雷电防护有相应的国际、国家与行业技术规范,但发生雷击事故现场仍然不能获取实质性的雷击参数,某些雷灾鉴定缺乏科学的定量数据,人们希望能有像飞机黑匣子那样的智能设备。所研究的黑匣子是一种在线监测、记录、还原雷击参数的智能仪表,对特定环境设施(如:避雷针、低压供、配电线路与信息传输线路)入侵的雷击具备在线实时监测、记录并还原雷击参数雷电流幅值、持续时间、极性(雷击电流走向)与波形的功能;且具有对在线电涌保护器(surge protective device,SPD)的动态预警管理效能。