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991.
LIANG Wei~ HU Hongying~ GU Xin~ CHE Yuling~ WANG Hui~ GUO Yufeng~ SONG Yudong~ . State Key Laboratory of Freshwater Ecology Biotechnology Institute of Hydrobiology Chinese Academy of Sciences Wuhan Hubei China . Environment Simulation Pollution Control State Key Joint Laboratory Department of Environmental Science Engineering Tsinghua University Beijing China 《武汉大学学报:自然科学英文版》2006,11(3):737-741
0 IntroductionMioclroogincuatlri pernotsce pslsaeys afo vrer wyais tmepwoarttaernt t rroelaetmine nbti- .A widerange of micronutrientsis required byactiva-ted sludge[1-5]. Adequate trace nutrient concentra-tions ,including metal ions and vitamins , are re-quiredtosupport all the genera presentinthe activa-ted sludgetreatment systemfor a diverse communityto survive. The lack of specific nutrients may resultin an unbalanced mixed culture,leading to poor-quality effluent , reduced treatment effic… 相似文献
992.
Djibrilla MOUSSA 《系统科学与系统工程学报(英文版)》2005,14(3):364-380
1. Introduction An early analysis of exchange rate changes and share prices found that the general stock market index tended to move up (down) immediately after a devaluation (revaluation) of the local currency (Giddy 1974). It is surprising that previous researches (Jorion 1990; Amihud 1993; Bodnar and Gentry 1993) find that no contemporaneous relationship between exchange rate changes and excess equity market returns of largest U.S. exporting firms. Recently, it has argued that there is a… 相似文献
993.
In this paper, a new triangular element (Quasi-Carey element) is constructed by the idea of Specht element. It is shown that this Quasi-Carey element possesses a very special property, i.e., the consistency error is of order O(h^2), one order higher than its interpolation error when the exact solution belongs to H^3(Ω). However, the interpolation error and consistency error of Carey element are of order O(h). It seems that the above special property has never been seen for other triangular elements for the second order problems. 相似文献
994.
LI Yanling DAI Guanzhong ZHU Yehang QIN Sen 《武汉大学学报:自然科学英文版》2007,12(5):902-906
Aiming at the importance of the analysis for public opinion on Internet, the authors propose a high-performance extraction method for public opinion. In this method, the space model for classification is adopted to describe the relationship between words and categories. The combined feature selection method is used to remove noisy words from the original feature space effectively. Then the category weight of words is calculated by the improved formula combining the frequency of words and distribution of words. Finally, the class weights of the not-categorized documents based on the category weight of words are obtained for realizing opinion extraction. Experiment results show that the method has comparatively high classification and good stability. 相似文献
995.
996.
The robust H∞ control problem was considered for a class of fuzzy hyperbolic model (FHM) systems with parametric uncertainties and multiple delays. First, FHM modeling method was presented for time-delay nonlinear systems. Then, by using Lyapunov-Krasovskii approaches, delay-dependent sufficient condition for the existence of a kind of state feedback controller was proposed, which was expressed as linear matrix inequalities (LMIs). The controller can guarantee that the resulting closed-loop system is robustly asymptotically stable with a prescribed H∞ performance level for all admissible uncertainties and time-delay. Finally, a simulation example was provided to illustrate the effectiveness of the proposed approach. 相似文献
997.
Bjørnar Sæther 《Systemic Practice and Action Research》2007,20(1):15-25
This paper describes the change in a researcher's practices from one of studying regional industrial development at a distance to one of working closely with a network of agri-food managers. This is accompanied by a discussion of the methodological and theoretical possibilities for an action research inspired economic geography. Some of the core characteristics of a pragmatic conceptualization of action research are revised. It is argued that theoretical developments within economic geography make possible a dialogue between researchers and local actors and that economic geography is challenged to accept that knowledge is generated through such a dialogue. Attempts to create a dialogue between action research and economic geography in a specific Norwegian industrial and geographical context are described. These attempts indicate that the researcher's methodological approach has been transformed from a narrow one relying solely on conventional social science methods to a broader one including participatory action research. 相似文献
998.
YANG XinLin CHEN Zhe MENG XianMei LI Bo TAN Xin 《科学通报(英文版)》2007,52(13):1802-1806
Activities of trimalonic acid fullerene (TMA C_60) on DNA restrictive enzymatic reaction were investigated by using two restrictive endonucleases Hind III and EcoR I and plasmid pEGFP-N1 with single restric-tive site for both enzymes. Meanwhile, TMA C60 was also tested to clarify its effects on polymerase chain reaction (PCR) with the catalyst of Taq DNA polymerase and the template of plasmid pEGFP-N1. The products from restrictive reactions or PCR were detected by agarose gel electrophoresis. It was found that the product amounts from restrictive reactions or PCR decreased significantly with addition of TMA C60. The inhibition by TMA C60 was dose-dependent and IC50 values for reactions of Hind III, EcoR I and PCR were 16.3, 6.0 and 6.0 μmol/L, respectively. Addition of two scavengers of reactive oxygen species (ROS), L-ascorbic acid-2-phosphate ester magnesium and sodium azide at the con-centrations of 2―10 mmol/L did not antagonize the activities of TMA C60 against PCR and two restrictive reactions. However, increase of Taq DNA polymerase amounts in PCR system antagonized the activities of TMA C60. These data implied that TMA C60 was able to inhibit the activities of the three above-mentioned enzymes involved in DNA metabolism, and that this inhibition probably did not correlate to ROS. 相似文献
999.
试论五人制足球的特点及其在甘肃高校推广的意义 总被引:3,自引:0,他引:3
五人制足球运动具有经济性、观赏性、适宜性、安全性等特点.甘肃的地理环境、气候特点和经济条件非常适合五人制足球运动的开展.在甘肃高校推广和普及五人制足球运动,可有效提高体育教学与训练效果,促进校园体育文化建设. 相似文献
1000.
以二甲苯为油相 ,氧氯化锆、氯化钇和氯化铝的混合水溶液为水相 ,聚氧乙烯失水山梨醇单油酸酯为表面活性剂 ,采用溶胶 -乳状液 -凝胶法合成了掺杂Al2 O3的Y -TZP超细粉末 .通过热重 (TG)、差热 (DTA)、XRD ,分析了由凝胶粉末热解至Y -TZP粉末的转变过程 .用TEM观察了粉末的形貌和分散状态 .探讨了Y -TZP粉末形成和生长过程 .实验表明 ,约在 50 0℃ ,凝胶转变为Y -TZP固溶体 ;在 550℃下焙烧制备的Y -TZP粉末粒径为 8~ 1 0nm ;在 1 1 0 0℃下所得烧结体的相对密度达 96% ;粉末在高温下能保持很高的四方相含量 相似文献