The Remediation of Perchloroethylene Contaminated Groundwater by Nanoscale Iron Reactive Barrier Integrated with Surfactant and Electrokinetics     

Shin-Shian Chen  Yi-Chu Huang  Tzu-Yen Kuo 《Ground Water Monitoring & Remediation》2010,30(4):90-98

In this study, nanoscale zero-valent iron (NZVI) particles were synthesized and utilized to integrate with surfactant and electrokinetics for the remediation of perchloroethylene (PCE). The average particle diameter and specific surface area of the lab-synthesized iron particles were 109.3 nm and 129.7 m² g^–1, respectively. Experiments were performed in a glass sandbox to simulate the transport and degradation of PCE in the aquifer. The results of the transport tests revealed that the PCE concentrations at the bottom layer was higher than those at the mid and upper layers, and that the surfactant Tween 80 showed its conspicuous mobilization for PCE in the aquifer. As the results of the degradation tests showed, NZVI activity could be promoted by electrokinetics that enhanced the remediation performance of PCE contaminated groundwater by the NZVI reactive barrier. Chlorinated byproducts were not detected during the degradation tests, that is, PCE was completely dechlorinated by NZVI in the reactive barrier. The information collected from this study will be useful for further application of the NZVI reactive barrier system to remediate the aquifers contaminated by the chlorinated solvents.  相似文献   

广州市美丽乡村空间分异特征及其影响因素   总被引：1，自引：0，他引：1  

张晨  肖大威  黄翼 《热带地理》2020,40(3):551-561

以广州市已公布的4批美丽乡村建设试点数据为基础，通过最邻近指数、基于Riple’s函数的多距离空间聚类分析、核密度分析和叠置分析等方法，探讨了广州市美丽乡村的发展现状、空间分布格局及其影响因素。结果表明：1）自2013年起，广州市美丽乡村数量逐年递增且增长率呈现上升趋势；2）广州市美丽乡村空间分布呈明显的集聚型分布；3）Ripley’s函数分析表明美丽乡村要素点空间分布格局随距离变化略有不同，在0.14 km处集聚强度达到最大；4）核密度分析显示美丽乡村高密度区域主要分布在广州南部和西北部，包括番禺－南沙1个热点主核心区和从化、花都－白云2个热点副核心区，密度分布呈现多核心不均衡特点；5）乡村的地形水文、人文历史、交通区位和政策规划为美丽乡村空间分布的主要影响因素，其中，政策规划因素对“美丽乡村群”空间格局的形成起决定性影响。空间分布特征总体反映出广州市美丽乡村规划建设初见成效，并逐步形成以热点核心区为基础的“美丽乡村群”。最后，在乡村选点、空间优化、价值提升以及乡村治理等方面提出若干建议。  相似文献   

等离子体背景参数对尖峰辐射的影响     

黄光力  王德焴 《中国天文和天体物理学报》1991,(4)

本文在电子回旋脉塞不稳定性理论的基础上,着重讨论了等离子体背景参数ω_(pe)/Ω_e对尖峰辐射性质的影响,内容包括:该参数的物理意义、取值范围,以及在尖峰辐射性质中,对ω_(pe)/Ω_e的变化比较敏感的偏振和谐波结构,等等。  相似文献   

Impact of the Kuroshio Current on the South China Sea based on a 115 000 year diatom record     

Hui Jiang  Svante Bjrck  Lihua Ran  Yue Huang  Jiayin Li 《第四纪科学杂志》2006,21(4):377-385

We used the tropical oceanic planktonic diatom species Nitzschia marina, Rhizosolenia bergonii and Azpeitia africana/Azpeitia neocrenulata, most commonly found in the surface sediments of the northeasternmost South China Sea (SCS) where the Kuroshio Current enters the SCS through the Bashi Strait north of Luzon, to analyse the influence of the the Kuroshio Current on the SCS. The impact of the Kuroshio Current seems to be relatively strong during major warm periods and, to a lesser degree, in minor warm periods during the last 115 000 years. The strongest influence took place during the main part of the Holocene and during the very late phase of Marine Isotope Stage (MIS) 5e. It is possible to distinguish two magnitudes of change in the impact of the Kuroshio Current on the SCS: large changes occurred at shifts between glacial and interglacial conditions, while smaller changes seem to have recurred in both glacial and interglacial episodes as well as during the Holocene. Climatic/oceanographic changes and sea‐level variations were possibly the two most important mechanisms for the varying influences of the Kuroshio Current on the SCS. The interaction between the Kuroshio Current and monsoon‐related processes may also have played a role. However, because of restricted knowledge of the present‐day Kuroshio Current and the absence of a modern analogue to the ancient SCS due to the marked changes in palaeogeography, this relationship is difficult to establish. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

厦门GPS基准站建设与试运行     

张远城  熊先保  黄晓华 《大地测量与地球动力学》2003,23(3):125-126

全面叙述中国地壳运动观测网络中25个基准站之一——福建GPS基准站的设计、选址、建造和仪器安装等建设过程及试运行至今的情况和有关参数。其中对某些防护措施如防雷措施有较详细说明。为今后GPS基准站的建设提供了系统性的经验。  相似文献   

成都花卉塑料薄膜大棚热量平衡初探     

黄斌  罗秀陵 《成都信息工程学院学报》1993,(3)

本文在测量的基础上,对热量平衡各分量在大棚内、外的差异,进行了比较与分析,对大棚生产管理有重要参考价值。  相似文献   

Study on methods of land use dynamic monitoring at county level     

Lin-yi Li  Fang Huang  Zhao-li Liu  En-pu Wan 《中国地理科学(英文版)》2001,11(2):181-185

Remote sensing technique has played an important role in land use dynamic monitoring, but as for the land use dynamic monitoring at county level, traditional remote sensing methods such as satellite imagery visual interpretation and computer classification can not meet its demand for accuracy. The result of 1: 10 000 land use investigation map has high accuracy, but this method can not be used to dynamically monitor the land use because of its big expenses, long period and difficulty in updating data. In this paper, the characteristics of physiognomy, climate and the status of land use in Dehui County are taken into consideration and a set of method, which takes use of 3S techniques and applies to Northeast China Plain, is come up with. When the land use type of a land parcel changed as a whole, the date updating can be make by changing its land type ID in the attribute table in a GIS. When the land use type of an irregular area changed, GPS receivers are used to position its border. This set of method is characteristic of high accuracy and low expenses. It gets the information of land use change timely and can be used to dynamically monitor the land use. Foundation item: Under the auspices of the key project of the National Ninth Five-year Plan (96-B02-01-07). Biography: LI Lin-yi (1968 —), female, a native of Jilin, Ph. D. candidate of Changchun Institute of Geography, the Chinese Academy of Sciences. Her research interest includes land use change monitoring and crop yield estimation using “3S” techniques.  相似文献   

Some characteristics of pulsations in radio bursts at 9.375 GHz     

Zhihai Qin  Guangli Huang 《Astrophysics and Space Science》1994,218(2):213-222

A type of pulsation in a time scale of seconds superimposed on microwave burst at 9.375 GHz has been found during the twenty-second solar active maximum period by us. This phenomenon is quite different from radio spike emission at decimeter and long centimeter wavelengths. The flux level of the bursts rises as the repetition rate of pulsations increases, following an approximate linear relationship. This feature resembles that at mm wavelength, but some other features are different. Some mechanisms for interpretation have been proposed.  相似文献   

山区≥10℃积温推算方法的讨论     

黄克新  宁晓松 《山地学报》1991,(1)

本文探讨了几种推算山区≥10℃积温的方法,认为由我国学者所采用的直方图推算法以及计量地理学中的三元线性回归数学模型推算法,在实际应用中都存在不完善和局限性,将两者结合起来进行复合推算,是一种较理想的研究方法。  相似文献   

Harmonic Structures of Gyrosynchrotron Radiation and Cyclotron Maser Instability     

Ai-Hua Zhou  Guang-Li Huang 《中国天文和天体物理学报》2001,1(4):365-371

1 INTRODUCTIONSolar microwave bursts are usually produced by dtherellt radiation mechanisxns: gyroresonance absorption, Coulomb brernsstrahlung of the thermal baCkground plasma, as well asgyrosynchrotron radiation of the nonihermal electrons (Hildebrandt et al. 1998). Meanwhile,cyclotron or synchrotron maser instabilities may be responsible for microwave spaaes, blips, andtype ill bursts (Wu 1985; Huang 1987; Huang et al. 1996; Huang 1998), which are usuajly superposed on the ambient mi…  相似文献