将军与地震幸存者

1992年9月的一天,北京长安街西部中央电视台彩电中心的演播大厅里灯火辉煌,著名电视主持人赵忠祥、杨澜正和剧组一块筹备录制《正大综艺》第13l期节目,这期节目是国家地震局(现中国地震局)为配合联合国国际减     

昆虫飞行之谜

世界上有成千上万种昆虫,大多数都会飞。然而,长期以来人们对昆虫的飞行都困惑不解。比方说,一只普通的家蝇侧面朝上向天花板飞去,蓦地落到天花板上。它是怎样控制得如此娴熟完成这样高难度的颠倒“着陆”动作的呢?再比如,蜻蜓的飞行又是怎样达到每小时90多公里的高速的?还有,有些     

Enhanced debromination of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) by zero-valent zinc with ascorbic acid

• Highly efficient debromination of BDE-47 was achieved in the ZVZ/AA system. • BDE-47 debromination by the ZVZ/AA can be applied to a wide range of pH. • AA inhibits the formation of (hydr)oxide and accelerates the corrosion of ZVZ. • Reduction mechanism of BDE-47 debromination by the ZVZ/AA system was proposed. A new technique of zero-valent zinc coupled with ascorbic acid (ZVZ/AA) was developed and applied to debrominate the 2,2′,4,4′-Tetrabromodiphenyl ether (BDE-47), which achieved high conversion and rapid debromination of BDE-47 to less- or non-toxic forms. The reaction conditions were optimized by the addition of 100 mg/L ZVZ particles and 3 mmol/L AA at original solution pH= 4.00 using the solvent of methanol/H₂O (v:v= 4:6), which could convert approximately 94% of 5 mg/L BDE-47 into lower-brominated diphenyl ethers within a 90 min at the ZVZ/AA system. The high debromination of BDE-47 was mainly attributed to the effect of AA that inhibits the formation of Zn(II)(hydr)oxide passivation layers and promotes the corrosion of ZVZ, which leads to increase the reactivity of ZVZ. Additionally, ion chromatography and gas chromatography mass spectrometry analyses revealed that bromine ion and lower-debromination diphenyl ethers formed during the reduction of BDE-47. Furthermore, based on the generation of the intermediates products, and its concentration changes over time, it was proposed that the dominant pathway for conversion of BDE-47 was sequential debromination and the final products were diphenyl ethers. These results suggested that the ZVZ/AA system has the potential for highly efficient debromination of BDE-47 from wastewater.     

Little Egrets (Egretta Garzetta) and Trace-Metal Contamination in Wetlands of China

The rapidly developing Asian countries may face threatening environmental contamination, that however remains largely unassessed. We studied persistent trace elements in three wetlands, Poyang Lake, relatively unpolluted, and Tai Lake, and Pearl River Delta, selected as hotspots of pollution in Central China. We adopted as indicator the Little Egret, a widespread colonial waterbird, and during 1999 and 2000 we collected and analysed the same samples as for a parallel study we conducted in Pakistan, e.g. eggs, body feathers of chicks, prey spontaneously regurgitated by the chicks, and sediments at the areas most used by foraging egrets. The levels of trace-metals at our three study areas were similar, or within the range, of those found in the few other studies for East Asia, with few exceptions. The concentrations of the various elements were below the threshold that may affect the survival or reproduction of the birds, and even the highest concentrations relative to background, i.e. Se in eggs, and Hg in feathers at Pearl Delta, do not pose toxic hazards. In sediments, the levels of trace elements were lower than the critical levels assumed for contaminated soil, except for alarming high levels of As at Poyang. These results do not confirm our expectation, that Poyang was relatively uncontaminated, while Tai and Pearl were polluted. Although trace metal concentration differed significantly among the three study areas, these differences were minor and were not consistent among elements and samples. The bioaccumulation ratios from sediments through prey, feather and egg, were consistent with our previous findings for Pakistan. Only Hg exhibited high bioaccumulation, while Se and Zn had low accumulation, and the other elements no accumulation. This reasserts that feathers of predators such as egrets, may be more sensitive indicators of environmental contamination for the elements subject to bioaccumulation, whereas the sediments or the organisms low in the food chain are better indicators for the other elements.     

剩余污泥的电化学稳定实验研究

研究了电化学法对城市剩余污泥稳定化的影响。结果表明,以钛涂钌电极为阳极、不锈钢板为阴极,在极板间距为2cm,电压为20V,曝气量为3L/h的条件下,电解20min,其挥发性悬浮物质(VSS)去除效率可达39%,加酸调节pH值至4左右时,其电解效率则可达40%以上,同时,污泥病原体达到未检出水平。     

控制轨道交通噪声道间声屏障研究

应用环境噪声预测与分析软件SOUNDPLAN对将设置在上海轨道交通6#线上下行线之间的道间声屏障插入损失进行了模拟计算。计算结果表明,安装道间声屏障可使得距离线路20～30m远的较高层建筑获得2～4.7dB的降噪效果;随着两侧声屏障高度的增加,安装道间声屏障对待测表面的影响范围在缩小;离轨道线路越近,道间声屏障的插入损失越大。     

Effect of fipronil on biogas production performance during anaerobic digestion of chicken manure and corn straw

Fipronil is a broad-spectrum insecticide that has a good control effect on pests of commercial poultry. Although many studies have reported the environmental fate of fipronil, the influence of residual fipronil in poultry waste on biogas production has not been further explored yet. In this article, an experimental comparative study on anaerobic digestion (AD) of chicken manure (CM) and corn straw (CS) with different fipronil concentrations (FCs) was carried at 8% of total solid (TS) and mid-temperature (35?±?1)°C. The results showed that fipronil had a significant effect on biogas production during AD of CM and CS. When the FC is at a low level (≤10?mg·kg^?1), the biogas production rate is increased and the digestion period was shortened, while higher FC (≥ 20?mg·kg^?1) showed an inhibitory effect. During the monitoring of enzyme activity, low FC showed no significant effect on cellulase and saccharase, but the urease activity increased in the early stage. High FC showed inhibition of activity of cellulase and urease, but the saccharase activity was significantly inhibited until FC reached 40?mg·kg^?1. This study also confirms that the environment in anaerobic digester is favorable for the degradation of fipronil, and its half-life is about 15.83?days.     

Probabilistic health risk assessment of nitrosamines in drinking water of Shaoxing,Zhejiang, China

Environmental Science and Pollution Research - Nitrosamines (NAms) are potent genotoxic and carcinogenic but widely detected in drinking water. This study aimed to investigate the occurrence of...     

红壤和黄泥土对不同浓度六氯苯的吸附与解吸特征

采用批量平衡试验的方法,研究了不同初始浓度的六氯苯在红壤和黄泥土表面的吸附与解吸特征. 结果表明,六氯苯在红壤和黄泥土表面的吸附与解吸行为均可用Freundlich方程进行很好的拟合,其相关系数(R2)在0.97-0.99之间,并表现为非线性特征. 六氯苯在红壤和黄泥土上吸附的KadsF值均小于其解吸的KdesF值,说明六氯苯在这两种土壤表面的解吸表现为一定的滞后效应. 随着初始浓度的升高,其滞后效应增强,两者呈线性相关. 用不同方程对滞后系数H,ω和λ进行量化,发现不同浓度的六氯苯在土壤表面的解吸过程表现出正滞后效应.     

特种服装特殊性的研究

本文通过对特种服装的广泛调查,总结、归纳出它们与一般服装的不同之处,也即它们的特殊性.本文对这些特殊性进行了详细地分析研究,并深入地研究出这些特殊性之间的内部联系,对特种服装的生产、管理、开发乃至应用有指导性的作用.