香溪河小水电的梯级开发对浮游藻类的影响

以香溪河干流上5个连续的小水电站为对象,于2005年10月20—22日分别对其浮游藻类和主要理化指标进行研究.结果表明:硅藻占绝对优势(95.54%),其中,线性曲壳藻(Achnanthes linearis)、披针曲壳藻椭圆变种(A.lanceolatavar.elliptica)、扁圆卵形藻(Cocconeisplacentula)为绝对优势种,其平均相对丰富度分别为23.96%、18.62%和12.48%;所有样点的平均藻类密度为6.29×105ind.L-1,最高为1.81×106ind.L-1

Electrocatalytic Activity of Palladium Nanocatalysts Supported on Carbon Nanoparticles in Formic Acid Oxidation

采用化学还原法制备了碳纳米粒子支撑的钯纳米结构(Pd-CNP). 透射电镜表征显示在Pd-CNP纳米复合物中，金属Pd呈菜花状结构，粒径约20~30 nm。它们由许多更小的Pd纳米粒子（3~8 nm）组成. 电化学研究表明，虽然Pd-CNP的电化学活性面积比商业Pd黑低40%（可能原因是部分Pd表面被一层碳纳米粒子覆盖），但其对甲酸氧化却表现出更好的电催化活性：质量比活性和面积比活性都比Pd黑高几倍. 催化活性增强的原因可能是碳纳米粒子支撑的Pd纳米结构具有特殊的层次化结构，可以形成更多的活性位，以及表面位更利于反应进行.Palladium nanostructures were deposited onto carbon nanoparticle surface by a chemical reduction method. Transmission electron microscopic studies showed that whereas the resulting metal-carbon (Pd-CNP) nanocomposites exhibited a diameter of 20 to 30 nm, the metal components actually showed a cauliflower-like surface morphology that consisted of numerous smaller Pd nanoparticles (3 to 8 nm). Electrochemical studies showed that the effective surface area of the Pd-CNP nanoparticles was about 40% less than that of Pd black, possibly because the Pd nanoparticles were coated with a layer of carbon nanoparticles; yet, the Pd-CNP nanocomposites exhibited marked enhancement of the electrocatalytic activity in formic acid oxidation, as compared to that of Pd black. In fact, the mass- and surface-specific activities of the former were about three times higher than those of the latter. This improvement was likely a result of the enhanced accessibility of the Pd catalyst surface and the formation of abundant active sites of Pd on the carbon nanoparticle surface due to the hierarchical structure of the metal nanocatalysts.This work was supported, in part, by the National Science Foundation (CHE–1012256 and DMR–0804049) and by the ACS-Petroleum Research Fund (49137–ND10). J. H. was supported, in part, by a research fellowship from the China Scholarship Council. TEM work was performed as a User Project at the National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, which is supported by the US Department of EnergyThis work was supported, in part, by the National Science Foundation (CHE–1012256 and DMR–0804049) and by the ACS-Petroleum Research Fund (49137–ND10). J. H. was supported, in part, by a research fellowship from the China Scholarship Council. TEM work was performed as a User Project at the National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, which is supported by the US Department of Energy作者联系地址：1. 加利福尼亚大学化学与生物化学系，美国 圣克鲁兹 95064; 2. 西北工业大学凝固技术国家重点实验室，陕西 西安710072Author's Address: 1. Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States; 2. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China通讯作者E-mail：[email protected]

脑卒中患者上肢康复脑功能及其康复治疗技术

脑卒中患者的上肢运动功能障碍发生率高,恢复较难,严重影响患者的独立生活能力和生活质量。本文概括了脑卒中患者的上肢康复脑功能理论,并从中枢神经干预治疗和外周神经干预治疗两个方面介绍了现有的脑卒中上肢运动功能康复技术。文献查阅结果表明各类康复治疗手段具有不同的针对性和局限性,早期、科学和合理的综合康复训练才能最大程度地帮助脑卒中患者实现上肢运动功能的完全康复,回归正常生活

引水型电站对河流底栖动物栖息地的影响及生态需水量

于2005年12月至2006年5月,对香溪河干流一典型引水型电站——苍坪河电站取水对坝下河段底栖动物栖息地的影响及河道的最小生态需水量进行调查研究,利用加权可利用宽度法（Weighted Usable Width）分别计算了香溪河底栖动物3个主要的目（蜉蝣目、襀翅目和毛翅目）的各断面加权可利用宽度,并对各断面结果进行比较。结果表明,电站引水坝的取水使下游河段部分地出现干涸,3个目的加权可利用宽度显著减小。根据底栖动物加权可利用宽度与流量的回归关系,计算得香溪河底栖动物主要类群的最小生态需水量为3.8m^3/s

香溪河小水电的梯级开发对浮游藻类的影响

以香溪河干流上5个连续的小水电站为对象,于2005年10月20-22日分别对其浮游藻类和主要理化指标进行研究.结果表明：硅藻占绝对优势（95.54%）,其中,线性曲壳藻（Achnanthes linearis）、披针曲壳藻椭圆变种（A. lanceolata var. elliptica）、扁圆卵形藻（Cocconeis placentula）为绝对优势种,其平均相对丰富度分别为23.96%、18.62%和12.48%;所有样点的平均藻类密度为6.29×10^5 ind·L^-1,最高为1.81×10^6 ind·L^-1,最低为2.35×10^5 ind·L^-1.方差分析表明,流速变化是小水电站开发影响河流中浮游藻类的主要原因.电站取水坝的建立,使其下游生境（生境3）与其它4个生境显著不同,导致多个参数出现骤变,包括Margalef多样性指数、物种丰富度、属的丰富度、硅藻组成、硅藻百分含量等均受到显著影响

香溪河小水电的梯级开发对浮游藻类的影响

以香溪河干流上5个连续的小水电站为对象,于2005年10月20-22日分别对其浮游藻类和主要理化指标进行研究.结果表明：硅藻占绝对优势（95.54%）,其中,线性曲壳藻（Achnanthes linearis）、披针曲壳藻椭圆变种（A. lanceolata var. elliptica）、扁圆卵形藻（Cocconeis placentula）为绝对优势种,其平均相对丰富度分别为23.96%、18.62%和12.48%;所有样点的平均藻类密度为6.29×10^5 ind·L^-1,最高为1.81×10^6 ind·L^-1,最低为2.35×10^5 ind·L^-1.方差分析表明,流速变化是小水电站开发影响河流中浮游藻类的主要原因.电站取水坝的建立,使其下游生境（生境3）与其它4个生境显著不同,导致多个参数出现骤变,包括Margalef多样性指数、物种丰富度、属的丰富度、硅藻组成、硅藻百分含量等均受到显著影响

More on the mealybug

As reported in Spore 62 p10 and Spore 63 p8, the pink mealybug (Maconellicoccus hirsutus) is devastating trees and crops on a number of Caribbean islands. The Caribbean Agricultural Research and Development Institute (CARDI) has produced a four-page Factsheet on the mealybug which documents the arrival of the pest in the Caribbean and describes the identification of the pest, the symptoms it produces in affected plants (what to look for and where it is found), its distribution and the work being done on biological control. The Factsheet also gives clear, concise guidelines on what must and must not be done if a suspected infestation of pink mealybug is found. The Mealybug Referral Service c/o Information Centre CARDI UWI Campus St Augustine, TRINIDAD, WIfour-page Factsheet on the mealybug The Mealybug Referral Service c/o Information Centre CARDI UWI Campus St Augustine, TRINIDAD, W