城市电力供应系统公共安全风险评估体系及应用

城市电力供应系统与城市公共安全关系紧密，文章分析了导致城市电力供应系统故障或事故的主要风险因素、事故类型及其风险程度，建立了城市电力供应系统公共安全风险评估体系。利用建立的风险评估体系，对某市电力供应系统的安全性进行了风险评估，同时验证了该体系在城市电力供应系统风险评估中的良好适用性。     

Recent patterns of production for the main cereal grains: implications for food security in China

China’s large population and deteriorating environment have created great concern related to the sustainability of food production, especially since details related to this topic remain poorly studied. Thus, an integrated analysis of both crop yield and cultivated area is essential for gaining a better understanding of cereal grain production in China and for making corresponding policies designed to achieve food security. In this study, we adopt trend analysis of both provincial yield and cultivated area to assess the subsequent provincial-level cereal production sustainability between 1980 and 2011 with the goal of providing a better understanding of regional agricultural development. The results indicate that while maize shows the most promise for yield improvement, rice and wheat production is experiencing substantial yield stagnation among most provinces across mainland China. In addition, the trends in spatial patterns are prominently different from those of yields. The sizes of the main rice- and wheat-growing areas in China have declined greatly, suggesting that the related production of these cereals should attract more attention from land management planners and farmers. Specifically, the south-eastern coastal provinces have largely failed to sustain both crop yield and area, while the north-eastern provinces have witnessed thriving agricultural production during the last three decades. Moreover, we find that cereal production in China is significantly affected by governmental policies related to the agricultural sector. Thus, this analysis of food production in China will help policymakers to better understand how the potential implications of food security in China may be applicable to countries worldwide.     

含阶梯结构的高层楼梯井内烟气湍流及输运特征量的全局敏感性分析

高层建筑竖井火灾中影响因素众多,并且各因素对高层楼梯井火灾中重要现象、关键数值等的影响大小不一,使得此类火灾中的实验或理论研究成本较高。通过建立全局敏感性分析平台,定量考察了高层楼梯井结构所涉及因素的影响大小,并能够方便地筛选掉对所考察量影响较小的因素,以降低实验或计算成本。使用数值模拟方法,通过CFD软件对包含阶梯几何框架的高层楼梯井结构火灾进行了共计60次工况计算。并且根据计算结果,使用全局参数敏感性分析方法,得出建筑尺寸、热释放速率、环境参数对高层楼梯井内烟气湍流特性及输运特性的敏感性排序。结果表明,火源热释放速率对各输出参数的影响均占38%以上。     

乌东德水库水温预测及低温水减缓措施

乌东德水库为季调节水库,采用宽度平均的立面二维水温数学模型对水库水温结构进行预测,结果表明:乌东德水库水温结构呈季节性分层特征,电站运行对下游水温过程有一定程度的春季低温水和冬季高温水影响。如果采用单层取水方案,在2~8月的下泄水温低于坝址现状水温,最大降幅为2.0℃,下泄低温水将对坝下鱼类产卵繁殖产生不利影响。乌东德水电站拟采取分层取水的措施,对低温水较为敏感的鱼类产卵期3~6月采用叠梁门取水。相比于单层取水,叠梁门方案对低温水的改善效果较明显,下泄水温提高了0.8~1.1℃,能一定程度地减缓升温期水温延迟效应。     

南京北郊春季气溶胶吸湿性分析

大气气溶胶的吸湿性对气溶胶粒子的谱分布、云凝结核形成、气候强迫、人体健康等均有重要的影响.利用吸湿性串联差分迁移率分析仪(HTDMA)在2014年4月16日~5月21日对南京北郊的大气气溶胶吸湿特性进行观测.30~230 nm气溶胶粒子在90%相对湿度下的吸湿增长观测结果表明,气溶胶粒子的吸湿增长因子平均概率分布函数(GF-PDF)呈现明显的双峰分布,即一个占主导地位的强吸湿模态,和一个相对较小但仍很明显的弱吸湿模态.对吸湿性的日夜对比分析发现,整体上白天的气溶胶粒子吸湿性大于夜间气溶胶粒子,白天强吸湿模态的粒子数目比例高于夜间,夜间气溶胶粒子的外混合程度更高.利用HYSPLIT模式对气溶胶来源分析结果表明,观测期间南京北郊主要受到3类气团的影响.其中西北大陆气团背景下爱根核模态粒子在经过大陆的长距离输送过程后,老化程度较高,吸湿性也更强.而对于积聚模态粒子,则为来自东方气团的粒子吸湿性更强,强吸湿模态粒子数目比例也较高.局地气团背景下气溶胶粒子在各粒径段都具有较高的强吸湿比例.     

MicroRNA: a novel implication for damage and protection against ionizing radiation

Environmental Science and Pollution Research - Ionizing radiation (IR) is a form of high energy. It poses a serious threat to organisms, but radiotherapy is a key therapeutic strategy for various...     

Markers of oxidative stress and toxicant exposure among young waterpipe smokers in the USA

Waterpipe (aka hookah) tobacco smokers are exposed to toxicants that can lead to oxidative DNA and RNA damage, a precursor to chronic disease formation. This study assessed toxicant exposure and biomarkers of DNA [8-oxo-7, 8-dihydro-2′-deoxyguanosine (8-oxodG)] and RNA [8-oxo-7,8-dihydroguanosine (8-oxoGuo)] oxidative damage during smoking of flavored and non-flavored waterpipe tobacco. Thirty waterpipe smokers completed two counterbalanced 2-h lab waterpipe smoking sessions (flavored vs. non-flavored waterpipe tobacco). Urinary concentrations of 8-oxodG and 8-oxoGuo and expired carbon monoxide (eCO) were measured before and after the smoking sessions. A significant increase in the urinary concentrations of 8-oxodG (from 2.12 ± 0.83 to 2.35 ± 0.91 ng/mg creatinine, p = 0.024) and 8-oxoGuo (from 2.96 ± 0.84 to 3.45 ± 0.76 ng/mg creatinine, p = 0.003) were observed after smoking the non-flavored and flavored waterpipe tobacco, respectively. Our results also showed that the mean ± SD of eCO increased significantly after smoking the flavored (from 1.3 ± 1.1 to 20.3 ± 23.6 ppm, p < 0.001) and non-flavored waterpipe tobacco (from 1.8 ± 1.2 to 24.5 ± 26.1 ppm, p < 0.001). There were no significant differences in the means of 8-oxodG (p = 0.576), 8-oxoGuo (p = 0.108), and eCO (p = 0.170) between the flavored and non-flavored tobacco sessions. Smoking non-flavored and flavored waterpipe tobacco leads to oxidative stress and toxicant exposure. Our findings add to the existing evidence about the adverse effects of waterpipe tobacco smoking (WTS) and the need for strong policies to inform and protect young people from the risks of WTS.

     

Heterogeneous Fenton degradation of ofloxacin catalyzed by magnetic nanostructured MnFe2O4 with different morphologies

Environmental Science and Pollution Research - Magnetic nanostructured MnFe2O4 with different morphologies, synthesized via chemical co-precipitation and hydrothermal method, was assayed as...     

Experimental study on static and dynamic mechanical properties of phosphogypsum

Environmental Science and Pollution Research - Phosphogypsum (PG) is a solid waste product of the wet-process phosphoric acid industry that accumulates in large amounts on the ground, forming PG...     

Feasibility of nanoscale zerovalent iron-loaded sediment-based biochar (nZVI-SBC) for simultaneous removal of nitrate and phosphate: high selectivity toward dinitrogen and synergistic mechanism

Environmental Science and Pollution Research - In the process of water treatment, excessive nitrogen and phosphorus pollutants are of great concern. Therefore, we prepared nanoscale zerovalent iron...