Trace metal (Cu, Zn, Pb, Cr and Cd) concentrations of three subfractions of organic matter from Lake Mariut sediments, Egypt

Trace elements associated with organic subfractions (humic, fulvic, and non-humic substances) were identified for seven core sediments from Lake Mariut, Egypt. Results indicated that the amounts of trace metals in humic acid and non-humic substances decreased in the following order: Zn>Cu>Pb>Cr>Cd, while in fulvic acid the order the order was Cu>Zn>Pb>Cr>Cd. There is a higher contribution of Zn, Pb, Cu and Cr in humic acid compared to fulvic acid in most samples. Slight changes in the amounts of cadmium bounded with humic and fulvic acids was also found.

Pb~(2+)胁迫对绿球藻(Chlorococcum sp.)的影响研究

研究了不同Pb2+浓度(0.1、1、10、50、100、200、400 mg/L)处理对绿球藻(Chlorococcum sp.)生长、形态结构及生理特性的影响。与对照BG11培养的绿球藻比较,Pb2+浓度≤50 mg/L条件下培养的绿球藻细胞壁无明显增厚,色素变化不大;而暴露到Pb2+浓度>50 mg/L条件下培养,绿球藻细胞壁明显增厚,蛋白核消失。低浓度Pb2+(0.1~10 mg/L)对绿球藻生长基本没有影响;浓度在50 mg/L时,绿球藻仍能维持一定的生长速率;但当Pb2+浓度≥100 mg/L时

重金属Cd~(2+)、Pb~(2+)和Zn~(2+)对泥鳅DNA损伤的研究

采用单细胞凝胶电泳技术(SCGE),研究重金属Cd2+、Pb2+、Zn2+在不同暴露时间(1—35d)、单一重金属离子不同暴露浓度(0.05mg/L、0.5mg/L、5.0mg/L)或混合重金属离子(Cd2++Pb2+、Cd2++Zn2+、Pb2++Zn2+、Cd2++Pb2++Zn2+)相同浓度(0.5mg/L)条件下对泥鳅肝胰脏细胞核DNA的损伤作用。以带彗尾核DNA百分率和彗尾长度(TL)与核直径(D)比值为指标,探讨DNA损伤级别与处理浓度间的相关性。结果显示,随着处理时间的延长,带彗尾核DNA百

~(210)Pb和~(137)Cs法对比研究武汉东湖现代沉积速率

对采自东湖 站和 站的沉积物采用210Pb和137Cs相结合的方法测定沉积速率,210Pb法测出东湖 站和 站的沉积速率为8.73mm/a和6.90mm/a,137Cs测出东湖 站和 站的沉积速率为7.4mm/a和5.8mm/a.分析了两种方法测定结果差异产生的原因,并与以往的研究相对比,探讨东湖沉积速率空间分布的规律性,沉积速率变化与人类活动的关系、沉积速率与扰动的关系.

Measurement of Residual Stresses in Ferroelectric Pb(Zr

The residual stresses in Pb(Zr0.3Ti0.7)O3thin films were measured by the \sin^{2}\Psi method using the normal X-ray incidence. The spacing of different planes (hkl) parallel to the film surface were converted to the spacing of a set of inclined planes (100). The angles between (100) and (hkl) were equivalent to the tilting angles of (100) from the normal of film surface. The residual stresses were extracted from the linear slope of the strain difference between the equivalent inclined direction and normal direction with respect to the \sin^{2}\Psi. The results were in consistency with that derived from the conventional \sin^{2}\Psi method.

Polarization switching induced decrease of bulk resistivity in ferroelectric Pb(Zr0.45Ti0.55)O3 thin films and a method to improve their fatigue endurance

Significant reduction of the bulk resistivity in a ferroelectric Pb(Zr 0.45Ti0.55)O3 thin film is observed before the remnant polarization started to decrease noticeably at the onset of its fatigue switching process. It is associated with the increase of charge carriers within the central bulk region of the film. The decrease of bulk resistivity would result in the increase of Joule heating effect, improving the temperature of the thin film, which is evaluated by the heat conduction analysis. The Joule heating effect in turn accelerates the polarization reduction, i.e. fatigue. Enhancing the heat dissipation of a ferroelectric capacitor is shown to be able to improve the device's fatigue endurance effectively. © 2013 Chinese Physical Society and IOP Publishing Ltd.

Measurement of residual stresses in ferroelectric Pb(Zr 0.3Ti0.7)O3 thin films by X-ray diffraction

The residual stresses in Pb(Zr0.3Ti0.7)O3 thin films were measured by the sin2 Ψ method using the normal X-ray incidence. The spacing of different planes (hkl) parallel to the film surface were converted to the spacing of a set of inclined planes (100). The angles between (100) and (hkl) were equivalent to the tilting angles of (100) from the normal of film surface. The residual stresses were extracted from the linear slope of the strain difference between the equivalent inclined direction and normal direction with respect to the sin2 Ψ. The results were in consistency with that derived from the conventional sin2 Ψ method. © 2013 The Japan Society of Applied Physics.

Use of microbial community to evaluate performance of a wetland system in treating Pb/Zn mine drainage

The performance of a wetland system in treating lead (Pb)/zinc (Zn) mine drainage was evaluated by using the polyurethane foam unit (PFU) microbial community (method), which has been adopted by China as a standardized procedure for monitoring water quality. The wetland system consisted of four cells with three dominant plants: Typha latifolia, Phragmites australis and Paspalum distichum. Physicochemical characteristics [pH, EC, content of total suspended solid (TSS) and metals (Pb, Zn, Cd, and Cu)] and PFU microbial community in water samples had been investigated from seven sampling sites. The results indicated that the concentrations of Pb, Zn, Cd, Cu, and TSS in the mine drainage were gradually reduced from the inlet to the outlet of the wetland system and 99%, 98%, 75%, 83%, and 68% of these metals and TSS respectively, had been reduced in concentration after the drainage passed through the wetland system. A total of 105 protozoan species were identified, the number of protozoa species and the diversity index (DI) gradually increased, while the heterotrophic index (HI) gradually decreased from the inlet to the outlet of the wetland system. The results indicated that DI, HI, and total number species of protozoa could be used as biological indicators indicating the improvement of water quality.

In(Ti,Sn)-O 与Sn(Pb)Zn-Te 的电子结构研究

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