Advances in air pollution control for vessels in China

Vessel emissions have contributed a great deal to air quality deterioration in China. Hence,the Chinese government has promulgated a series of stringent emission regulations. It is in this context that vessel emission control technology research is in full swing. In particular,during the 13th Five-Year Plan, the air pollution control technology of vessels has greatly improved. Vessel emission control has followed two main governance routes: source emission reduction and aftertreatment technology...     

Role of the rhizosphere of a flooding-tolerant herb in promoting mercury methylation in water-level fluctuation zones

The water-level fluctuation zone (WLFZ) has been considered as a hotspot for mercury (Hg) methylation. Flooding-tolerant herbs are gradually acclimated to this water-land ecotone, tending to form substantial root systems for improving erosion resistance. Accompanying rhizosphere microzone plays crucial but unclear roles in methylmercury (MeHg) formation in the WLFZ. Thus, we conducted this study in the WLFZ of the Three Gorges Reservoir, to explore effects of the rhizosphere of a dominant flooding-tolerant herb (bermudagrass) on MeHg production. The elevated Hg and MeHg in rhizosphere soils suggest that the rhizosphere environment provides favorable conditions for Hg accumulation and methylation. The increased bioavailable Hg and microbial activity in the rhizosphere probably serve as important factors driving MeHg formation in the presence of bermudagrass. Simultaneously, the rhizosphere environments changed the richness, diversity, and distribution of hgcA-containing microorganisms. Here, a typical iron-reducing bacterium (Geobacteraceae) has been screened, however, the majority of hgcA genes detected in rhizosphere, near-, and non-rhizosphere soils of the WLFZ were unclassified. Collectively, these results provide new insights into the elevated MeHg production as related to microbial processes in the rhizosphere of perennial herbs in the WLFZ, with general implications for Hg cycling in other ecosystems with water-level fluctuations.     

Theoretical study on the degradation reaction of octachlorinated dibenzo-p-dioxin with atomic oxygen O(3P) in dielectric barrier discharge reactor

Dielectric barrier discharges （DBD） have been used in the degradation of dioxins due to the large number of excimers and free radicals produced in discharge process. In this article, the density functional theory （DFT） is used to study the degradation mechanism of octachlorinated dibenzo-p-dioxin （OCDD） with the atomic oxygen O（3P） in DBD reactor. The reactants, intermediates, transition states and products are optimized at the MPWB1K/6- 31 ＋ G（d,p） level. The vibrational frequencies have been calculated at the same level. The reaction pathways and mechanisms are analyzed in detail. The effect of removing the chlorine atom on environment also has been discussed.     

防弹衣的服用发展趋势

目前,防弹衣作为一种重要的防护装备,虽然其防弹性能已经得到了较大的提高,但其对使用者的活动和穿着舒适性有较大的限制和影响。因此,对防弹衣减重和舒适性的研究相当迫切。本文对国内外的防弹衣研究进展情况进行了介绍,并对防弹衣减重及舒适性发展的研究和未来趋势进行了探讨。     

浅谈石化行业脱硝技术的现状及发展

介绍了氮氧化物的危害,石化行业氮氧化物的产生机理和特点,我国现阶段石化行业氮氧化物主要来源,包括FCC再生烟气、装置加热炉烟气、酸性气回收装置废气。阐述了不同类型烟气中氮氧化物产生、治理措施、排放现状以及氮氧化物排放限制标准,并对将来石化行业脱硝技术的应用进行了探讨和展望。     

The governance of integrated ecosystem management in ecological function conservation areas in China

The relationship between ecological and socioeconomic systems in ecological function conservation areas (EFCAs) in China is analyzed from a governance perspective. Lashihai watershed in China’s southwestern Yunnan Province was chosen as a case study area, where leaders of 81 villager groups were interviewed through questionnaire surveys and anecdotal evidence was collected from focus group discussions. Our study found that the rehabilitated ecosystems in Lashihai, arising from conservation actions, provided the local communities with increasing natural capital to pursue horseback tourism as an important means of livelihood. Also, bonding social capital, together with unique cultural and ethnic assets, may have been instrumental in the formation of horseback tourism teams in some villager groups. However, the lack of higher-level government involvement and coordination among horseback tourism teams appeared to have led to a situation, where the rapidly developing tourism teams have started to impose threats on the wetland ecosystem. While highlighting some limitations of self-governance in adapting to complex and fast-changing socioeconomic conditions, the study called for the potential importance of fostering adaptive co-management to help modify the emerging undesired interconnectedness in social-ecological systems in Lashihai. For the future’s successful governance of integrated ecosystem management in EFCAs in China, the study also made brief discussion on some key elements of the adaptive co-management.     

非等压下考虑渗流和剪胀的圆巷围岩弹塑性统一解

对于富水地层中深埋圆形巷道,为研究多种因素影响下巷道围岩塑性区范围和洞周位移的变化规律,对巷道围岩进行了弹塑性理论分析。对围岩应力场和渗流场进行耦合分析,基于统一强度理论和非关联流动法则,推导出多种因素影响下深埋圆形巷道围岩应力、位移和塑性区半径的解析计算式。结合工程实例进行计算分析,结果表明:中间主应力参数、围岩侧压系数、初始孔隙水压和剪胀角对围岩塑性区径向位移和塑性区范围均有显著影响,但影响规律各不相同;考虑中间主应力作用时,其他各因素的影响效应减弱。综合考虑以上各因素对围岩稳定性的影响,计算结果更加接近工程实际情况。     

基于建筑材料物化环境影响的建筑结构形式选择

不同结构形式的建筑在环境影响方面存在差异。对砖混结构和框架结构的两种不同形式的建筑物,因使用建筑材料而造成的环境影响差异,依据建筑材料生命周期环境影响评价模型进行了定量分析。结果表明:从建筑物使用的建筑材料造成的环境影响角度分析,多层砖混结构单位建筑面积的资源耗竭系数为0.045、环境影响负荷为5.87;多层框架结构则分别为0.071、10.49。     

大型浮顶储罐浮盘密封圈雷击起火事故分析

通过对近年来连续发生的大型浮顶储罐浮盘密封圈雷击起火原因分析,找出了浮顶储罐浮盘密封存在的安全问题,探讨了浮盘密封形式与储罐雷击起火事故的关系,并提出对策措施.     

爆炸冲击环境下内凹蜂窝型梯度结构响应特性研究*

为提升应急救援人员防护服抗爆能力,减少爆炸事故中人员伤亡数量,以内凹蜂窝型梯度结构为研究对象,采用爆炸冲击实验与数值有限元法相结合的研究手段,通过改变胞元尺寸与胞元凹角对梯度蜂窝结构进行优化,分析梯度结构在爆炸冲击环境下冲击波衰减效率和力学响应规律。结果表明:同等质量条件下,内凹蜂窝结构尺寸梯度为2.58 mm-3.40 mm-2.58 mm、角度梯度30°-22.5°-30°时对冲击波的衰减效应最佳,衰减效率分别为85.44%,82.29%。研究结果可为同时满足轻质、高强抗爆要求的防护服结构设计提供技术支撑。