Electrocatalytic dechlorination of 2,4,5-trichlorobiphenyl using an aligned carbon nanotubes electrode deposited with palladium nanoparticles

Palladium loaded carbon nanotubes cathode with well-aligned nanotubes array was successfully fabricated on a titanium foil (Pd/CNTs/Ti) using a chemical vapor deposition technique and subsequent electrochemical deposition method. Pd particles were well dispersed on CNTs wall surfaces with average sizes no more than 20 nm, in most cases around 10 nm. Experiments for dechlorination of 2,4,5-trichlorobiphenyl (PCB 29) in methanol/water solution were carried out for the first time using Pd/CNTs/Ti cathode for investigation of its performance in electrocatalytic dechlorination of PCBs. Results show that Pd/CNTs/Ti presented better dechlorination efficiency (up to 90% in 6 h) than Pd/Ti and Pd/graphite cathodes owing to unique properties owned by CNTs, which benefited enhanced dechlorination of PCB 29. Complete dechlorination for PCB 29 was observed and biphenyl was identified to be final dechlorination product. The amount of Pd loading, cathode potential, and electrolytes were found to be key factors influencing dechlorination performance.     

提高抑制流动分离能力的等离子体冲击流动控制原理

由于介质阻挡放电等离子体气动激励诱导的气流速度及其抑制流动分离的能力难以显著提升, 因此研究新的技术途径提高等离子体气动激励抑制流动分离的能力是十分必要的. 提出基于冲击气动激励的等离子体冲击流动控制原理, 包括冲击激励、涡流控制、频率耦合等内涵, 通过理论研究、实验和数值仿真, 研究了等离子体冲击气动激励机理, 以及等离子体冲击气动激励提高抑制流动分离能力的原理, 并在100 m/s来流速度下验证了等离子体冲击流动控制原理的有效性.     

氯化锌活化大麻布活性炭纤维的孔结构

以大麻布为原料,氯化锌为活化剂,在不同活化温度下制备大麻布活性炭纤维样品。采用低温氮气吸附和密度函数理论(DFT)等对样品的孔结构和表面能量分布等表面织构特征进行了研究。结果表明,样品BET比表面积随活化温度的升高呈现先增大后减小的变化趋势,800℃时达到最大值915 m2/g;样品是典型的微孔材料,孔分布集中于2 nm以下的微孔范围内,只有极少部分的中孔,基本没有大孔;样品的表面能量分布较宽,为不均匀性表面;随活化温度的升高,样品碘吸附量呈先增大后减小的变化趋势,与微孔孔容、总孔容以及由BET比表面积的变化趋势一致。     

亚热带森林生态系统不同重建方式下碳储量及其分配格局

森林重建被认为是提高生态系统碳汇功能的重要措施.通过调查研究了两种重建方式(自然更新和人工造林)对亚热带森林生态系统碳储量及其分配格局的影响,并与地带性常绿阔叶林进行了比较.结果表明,自然更新的次生林生态系统碳储量(植被+土壤+枯落物)约为257.59thm-2,人工营造的杉木(Cunninghamia lanceolata)林、蓝果树(Nyssasinensis)林分别为230.93和163.49thm-2,表明在亚热带九连山区,自然重建方式在森林碳汇功能上优于人工重建方式.但上述森林碳储量仍然显著低于地带性植被的碳储量(299.13thm-2),表明这些森林仍具有较大的碳汇潜力.自然重建方式经济投入少,对土壤碳库扰动较小,且植被碳储量显著高于速生人工林,说明在种源丰富、自然环境较好的亚热带林区,在30多年的时间尺度上自然重建方式具有较高的固碳效益,这对于我国碳汇林建设、提高生态系统的固碳效益具有重要的指导意义.     

Numerical simulation of March 11, 2011 Honshu, Japan tsunami

In order to predict tsunami hazards through numerical simulation,by using the focal mechanisms as well as fault parameters of Japan’s 2011 Tohoku Earthquake provided by National Geological Survey(referred to as USGS),we proposed a numerical model to simulate the Honshu,Japan tsunami.Numerical computing is conducted to investigate the security along the coast.We also analyzed the simulation results and distribution of tsunami disaster,trying to achieve a more reasonable tsunami warning program.Our numerical model is composed of simulation of surface deformation after the earthquake and the tsunami propagation process which is based on two dimensional shallow water equations.The simulation results show the characteristics of the tsunami propagation,and arrival times on recorder points are consistent with tsunami observation.This model can be applied to evaluate the security of the coastal area and obtain more accurate tsunami warning.     

试探英、汉文学作品中的情感隐喻类型

情感是文学作品中永恒的主题之一.隐喻作为一种语言现象,一种认知方式,在文学作品中起到了重要的作用：文学作品中借用隐喻让人们更充分、更深刻、更丰富地感受生活,从而加深对生活的理解.     

Factors affecting potassium fixation in seven soils under 15-year long-term fertilization

Potassium （K） fixation by seven soils, including black soil, fluvo-aquic soil, grey desert soil, loess soil, paddy soil, red soil and purple soil, was determined by laboratory simulation under a fifteen-year-period of long-term fertilization. Factors affecting soil K fixation were then discussed by factor analysis and stepwise regression. Magnitude of soil K fixation rate was as follows： the black soil 〉 the purple soil 〉 the loess soil 〉 the fluvo-aquic soil 〉 the paddy soil 〉 the grey desert soil 〉 the red soil. Our results showed that soil K fixation capacity was significantly affected by the clay mineral types in the soils. Potassium fixation capacity of soils, whose 2：1 layer silicates were dominant minerals, was affected by two components extracted by the method of principal component analysis： the first including soil available K, slow available K and K^＋ saturation, and the second including cation exchange capacity （CEC）, soil organic matter （SOM） and 〈0.002 mm clay contents. Potassium fixation rate was mainly affected by K^＋ saturation and CEC with lower added K concentration （from 0.4 to 1.6 g/L）, and by K^＋ saturation and 〈0.002 mm clay content with higher added K concentration （from 2.4 to 4.0 g/L）.     

加磁场制备FeCuNbSiB软磁合金薄膜的畴结构和巨磁阻抗效应

本文研究了用射频溅射法制备的Fe73．5CulNb3Si13．5B9薄膜的巨磁阻抗效应,并对其磁畴结构进行了分析．探讨在制备过程中加一纵向或横向稳恒磁场对薄膜各向异性场的影响．在制备过程中加磁场使得材料的软磁性能得到明显改善,矫顽力从400Am^（-1）降为60Am^（-1）,磁阻抗效应有较大提高．加横向磁场制备的Fe73．5CulNb3Si13．5B9薄膜的畴结构,不是严格的沿着样品的长方向,而是略向宽方向倾斜．经300℃退火后的FeCuNbSiB薄膜具有最大的磁阻抗效应,其纵向磁阻抗比为38％,横向磁阻抗比为27％,巨磁阻抗效应的磁场灵敏度分别为47．5％／kAm^（-1）和11．3％／kAm^（-1）．     

Spatial analysis of intra-site use at a Late Paleolithic site at Shuidonggou,Northwest China

Intra-site spatial analysis provides an alternative perspective for understanding the functions of a site, and the occupational organization of early human living and activities associated with it. We examined features and cultural remains recovered from Locality 2 at Shuidonggou, a Late Paleolithic site, focusing on early occupants’ survival behaviors and settlement patterns, as indicated by evidence regarding the functional organization of the site. Three-dimensional data from unearthed remains (including lithic assemblages, faunal remains, ornaments, etc) were used to reconstruct intra-site use patterns of Cultural Layer 2, which yielded seven earth-pit hearths and tens of thousands of artifacts and bones. We discuss the population size and group composition, as well as the functions of the living spaces, based on the analysis of the hearth patterns and the ostrich eggshell ornaments surround the hearths. In conclusion, Cultural Layer 2 of SDG Locality 2 appears to have functioned as a base camp for ancient foragers, where occupants produced tools, as well as preparing and consuming food.     

Enhanced photocatalytic degradation of tetracycline hydrochloride by molecular imprinted film modified TiO<Subscript>2</Subscript> nanotubes

To enhance the photocatalytic activity of TiO2 nanotubes,tetracycline hydrochloride(TC) molecularly imprinted titania modified TiO2 nanotubes(MIP-TiO2) was prepared by liquid phase deposition,which improved the molecular recognition ability of the photocatalyst toward template molecules.This MIP-TiO2 photocatalyst was characterized by ESEM and XRD,which showed that the imprinted titania was deposited on the nanotube uniformly and was of well-crystalized anatase-type.In the adsorption experiments,MIP-TiO2 exhibited a high adsorption capacity(about 1.6 times higher than that of TiO2 nanotubes) for TC mainly because of its imprinted sites and high surface area.Under UV irradiation MIP-TiO2 showed enhanced photocatalytic activity with an apparent first-order rate constant 1.9-fold that of TiO 2 nanotubes.