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961.
Deng DM Shu WS Zhang J Zou HL Lin Z Ye ZH Wong MH 《Environmental pollution (Barking, Essex : 1987)》2007,147(2):381-386
To investigate the variation of Zn and Cd accumulation and tolerance of Sedum alfredii (a newly reported Zn/Cd hyperaccumulator), field surveys and hydroponic experiments were conducted among three populations of this species: two originating from old Pb/Zn mines in Zhejiang (ZJ) and Hunan (HN) Provinces and one from a "clean" site in Guangdong (GD) Province, China. Under field conditions, up to 12,524 and 12,253 mg kg(-1) Zn, and 1400 and 97 mg kg(-1) Cd in shoots of ZJ and HN plants were recorded respectively. Under hydroponic conditions, ZJ and HN plants accumulated significantly higher Zn and Cd in their leaves and stems, and possessed significantly higher Zn and Cd tolerance than GD plants. Among the two contaminated populations, ZJ plants showed higher Cd tolerance and accumulation (in leaves) than HN plants. The present results indicate that significant differences in Zn and Cd accumulation and tolerance exist in populations of S. alfredii. 相似文献
962.
The distribution and dynamics of microcystins in various organs of the phytoplanktivorous bighead carp were studied monthly in Lake Taihu, which is dominated by toxic cyanobacteria. There was a good agreement between LC-MS and HPLC-UV determinations. Average recoveries of spiked fish samples were 63% for MC-RR and 71% for MC-LR. The highest MC contents in intestine, liver, kidney and spleen were 85.67, 2.83, 1.70 and 1.57 microg g-1 DW, respectively. MCs were much higher in mid-gut walls (1.22 microg g-1 DW) than in hind- and fore-gut walls (0.31 and 0.18 microg g-1 DW, respectively), suggesting the importance of mid-gut wall as major site for MC absorption. A cysteine conjugate of MC-LR was detected frequently in kidney. Among the muscle samples analyzed, 25% were above the provisional tolerable daily intake level by WHO. Bighead is strongly resistant to microcystins and can be used as biomanipulation fish to counteract cyanotoxin contamination in eutrophic waters. 相似文献
963.
Zhang JJ Wen B Shan XQ Zhang S Khan SU 《Environmental pollution (Barking, Essex : 1987)》2007,150(2):234-242
Residence time-dependent distribution patterns of hexachlorobenzene (HCB) and dichlorodiphenyltrichloroethane (DDT) among different soil organic matter fractions of three Chinese soils were investigated. Soil organic matter (SOM) was fractionated into fulvic acid (FA), humic acid (HA), bound-humic acid (BHA), lipid, and insoluble residue (IR) fractions using methyl isobutyl ketone (MIBK) method. Results revealed that as the residence time prolonged, the amounts of HCB and DDT in the FA, HA and BHA fractions decreased, while those in the lipid and IR fractions increased. One- and two-compartment first order, and one- and two-parameter pore-diffusion kinetic models were used to describe the mobility of HCB and DDT from the FA, HA and BHA fractions. The results suggest that excellent agreements were achieved between the experimental data and fits to the two-compartment first order kinetic model (R2>0.97). The transfer rates of HCB and DDT followed the order FA>HA>BHA. 相似文献
964.
Hai Zhao Dexiang Zhang Fangfang Wang Tingting Wu Jinsheng Gao 《Process Safety and Environmental Protection》2008,86(6):448-454
Fe–Mn oxide and Ce-doped Fe–Mn oxide sorbents were studied on the structural and desulfurization behavior in COS removal from syngas. The effects of cerium oxide on the Fe–Mn oxides have been investigated by XRD, BET, TPR, XPS and TEM methods. Analysis data show that the Ce-doped sorbent has larger specific surface area and better particles’ dispersion compared with non-modified Fe–Mn sorbent. The addition of Ce improves the reduction performance of Fe–Mn species. The desulfurization experiments show that the desulfurization activity of sorbent can be increased because of the promotion of the structural and redox properties by ceria doped. The Ce-doped sorbent can reduce COS from 15,000 ppmv to less than 0.1 ppmv at 325 °C and a space velocity of 1000 h−1. 相似文献
965.
966.
967.
1引言
防护装备在核、生、化环境下起着防放射性灰尘、防生物细菌和防化学毒剂的作用。防护装备的防护性能检测准确与否。直接影响着防护装备产品的质量乃至使用者的生命安全。防护装备的防护性能受湿度的影响很大,以前,在防护装备的防护性能检测过程中是利用干、湿球温度计来检测测试管路中的湿度。 相似文献
968.
本文提出了校准湿度计的一种新方法一测量不确定度分析校准法,以利用5121湿度发生器校准可输出(0-5)V的湿度传感器的基本误差为例,介绍了其校准方法确定了该方法校准湿度计的置信度和准确葭: 相似文献
969.
970.
TiO2-xNx光催化氧化苯甲酸的研究 总被引:3,自引:2,他引:1
采用悬浮态光催化反应体系,以氙灯为光源,自制纳米TiO2-xNx为催化剂,考察了苯甲酸光催化氧化过程中TiO2-xNx质量浓度、反应体系初始pH和苯甲酸初始质量浓度对苯甲酸溶液中TOC去除率的影响。实验结果表明:最佳催化剂质量浓度为0.30g/L;TiO2-xNx的等电点为pH=5.3,在酸性条件下(pH=2.0)更有利于苯甲酸在催化剂表面的吸附,以及光生电子与O2反应生成·OH的进行;随苯甲酸初始质量浓度增加,TOC去除率降低,反应速率也相应地降低。TiO2-xNx比P25型TiO2表现出更强的浓度适应能力。 相似文献