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Journal of Environmental sciences 2003年第3期15卷 423-432页

作者： zhang Dai-jun 1,2.(1. department of Environmental Science, Chongqing {2., Campus A, Chongqing 400044, china 2. Key Laboratory for the Southwest china Resources Exploitation and Environmental Disaster Control Engineering, Ministry of Education, china.) department of Environmental Science Chongqing University China

The integration of methanogenesis with denitrification and anaerobic ammonium oxidation(ANAMMOX) was studied in an expanded granular sludge bed(EGSB) reactor in this work. Experimental results from the continuous treatment of wastewater with nitrite and ammonium, which lasted for 107 days, demonstrated that wastewater with high nitrite and ammonium could be anaerobically treated in an expanded granular sludge bed reactor. More than 91% to 97% of COD were removed at up to about 3.9 g COD/(L·d) of COD volumetric loading rate. More than 97% to 100% of nitrite was denitrified at up to about 0.8 g NO -_2.N/(L·d), which is 16 times higher than that in a conventional activated sludge system with nitrification/denitrification(0.05 gN/(L·d)). No dissimilatory reduction of nitrite to ammonium occurred in the process. However, maximum of about 40% ammonium was found to be lost. Batch tests of 15 days with sludge from the reactor showed that 100% of nitrite was denitrified completely, and about 3% of ammonium was removed when only ammonium (34.3 mg/L) and nitrite(34.3 mg/L) were added into the sludge suspension medium. Furthermore, about 15% of ammonium amounts were lost with organic COD addition. It suggested that the methanogenesis in the system could enhance ANAMMOX because of intermediate hydrogen produced during methanogenesis.

关键词： methanogenesis denitrification ANAMMOX EGSB reactor

Formulae of type Ankeny-Artin-Chowla for class numbers of general cyclic sextic fields

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Chinese Science Bulletin 1998年第10期43卷 824-826页

作者： LIU Tong department of Applied Mathematics, tsinghua university, Beijing {2., china department of Applied Mathematics Tsinghua University Beijing China

Let K 6 be a real cyclic sextic number fields, and K 2. K 3 be its quadratic and cubic subfields. Let h(L) denote the ideal class number of field L. Seven congruences for h -=h(K 6)/h(K 2.h(K 3) are obtained. In particular, when conductor f\-6 of K 6 is prime p, then Ch -≡B p-16B 5(p-1)6 (mod p), where C is an explicitly given constant, and B n is the Bernoulli number. These results for real cyclic sextic fields are an extension of results for quadratic and cyclic quartic fields obtained by Ankeny_Artin_Chowla, Kiselev, Carlitz, Lu Hongwen, zhang Xianke from 1948 to 1988.

关键词： real cyclic sextic number fields class number fundamental relative unit.

ELASTO-PLASTICITY ANALYSIS BASED ON COLLOCATION WITH THE MOVING LEAST SQUARE METHOD

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Acta Mechanica Solida Sinica 2003年第2期16卷 162-170页

作者： Song Kangzu zhang Xiong Lu Mingwan (department of Engineering Mechanics,{2.,Beijing 100084,china) departmentofEngineeringMechanics TsinghuaUniversityBeijing100084China

A meshless approach based on the moving least square method is developed for elasto-plasticity analysis,in which the incremental formulation is *** this approach,the dis- placement shape functions are constructed by using the moving least square approximation,and the discrete governing equations for elasto-plastic material are constructed with the direct collo- cation *** boundary conditions are also imposed by *** method established is a truly meshless one,as it does not need any mesh,either for the purpose of interpolation of the solution variables,or for the purpose of construction of the discrete *** is simply formu- lated and very efficient,and no post-processing procedure is required to compute the derivatives of the unknown variables,since the solution from this method based on the moving least square approximation is already smooth *** examples are given to verify the accuracy of the meshless method proposed for elasto-plasticity analysis.

关键词： meshless method elasto-plasticity collocation method moving least square incremental formulation

Discovery of Permian island-arc basalts in the Cenxi area and the tectonic significance──A piece of evidence for the paleo-Tethyan tectonic belt in western Guangdong and eastern Guangxi

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Chinese Science Bulletin 1998年第21期43卷 1838-1842页

作者： zhang Boyou 1, ZHAO Zhenhua 1, SHI Manquan 1, YANG Shufeng 2.and CHEN Hanlin 2.1. Guangzhou Institute of Geochemistry, Chinese Academy of {2., Guangzhou 510640, china 2. department of Earth {2., Zhejiang university, Hangzhou 31002., china Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China department of Earth sciences Zhejiang University Hangzhou China

Cenxi Permian basalts are the late Palaeozoic island-arc type basalts first found in South china. REE and trace element characteristics and distribution patterns show that this volcanic formation, which has been isotopically dated at 2.1 MaB.P. by the 39Ar/ 40Ar method, is of an active continental marginal island arc type, and that the tectonic environment at that time was an island-arc marginal sea or minor ocean basin related with the paleo-Tethyan tectonic belt in western Guangdong-eastern Guangxi.

关键词： spilite-keratophyre pillow lava Permian continental margin paleo-Tethyan evolution.

Large eddy simulation of stably stratified turbulence

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Science china(Physics,Mechanics & Astronomy) 2010年第1期53卷 135-146页

作者： SHEN Zhi, LI YuPeng, CUI GuiXiang & zhang ZhaoShun department of Engineering Mechanics, {2., Beijing 100084, china 1. department of Engineering Mechanics Tsinghua University Beijing 100084 China

Stable stratification turbulence, as a common phenomenon in atmospheric and oceanic flows, is an important mechanism for numerical prediction of such flows. In this paper the large eddy simulation is utilized for investigating stable stratification turbulence numerically. The paper is expected to provide correct statistical results in agreement with those measured in the atmosphere or ocean. The fully developed turbulence is obtained in the stable stratification fluid by large eddy simulation with different initial velocity field and characteristic parameters, i.e. Reynolds number Re and Froude number Fr. The evolution of turbulent kinetic energy, characteristic length scales and parameters is analyzed for investigating the development of turbulence in stable stratification fluid. The three-dimensional energy spectra, horizontal and vertical energy spectrum, are compared between numerical simulation and real observation in the atmosphere and ocean in order to test the reliability of the numerical simulation. The results of numerical cases show that the large eddy simulation is capable of predicting the properties of stable stratification turbulence in consistence with real measurements at less computational cost. It has been found in this paper that the turbulence can be developed under different initial velocity conditions and the internal wave energy is dominant in the developed stable stratification turbulence. It is also found that the characteristic parameters must satisfy certain conditions in order to have correct statistical property of stable stratification turbulence in the atmosphere and ocean. The Reynolds number and Froude number are unnecessarily equal to those in atmosphere or ocean, but the Reynolds number must be large enough, say, greater than 10 2., and Froude number must be less than 0.1. The most important parameter is ReFr 2.which must be greater than 10.

关键词： stratified turbulence internal wave potential vortex large eddy simulation

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Lp shape deformation

Science china(Information sciences) 2012年第5期55卷 983-993页

作者： GAO Lin1,zhang GuoXin 1 & LAI YuKun 2.1 {2. of Computer Science and Technology,tsinghua university,Beijing 100084,china 2.School of Computer Science and Informatics,Cardiff university,Wales CF2. 3AA,UK 1. department of Computer Science and Technology Tsinghua University Beijing 100084 China2. School of Computer Science and Informatics Cardiff University Wales CF24 3AA UK

Shape deformation is a fundamental tool in geometric *** methods consider preserving local details by minimizing some energy functional measuring local distortions in the L 2.*** strategy distributes distortions quite uniformly to all the vertices and penalizes ***,there is no unique answer for a natural deformation as it depends on the nature of the *** by recent sparse signal reconstruction work with non L 2.norm,we introduce general L p norms to shape deformation;the positive parameter p provides the user with a flexible control over the distribution of unavoidable *** with the traditional L 2.norm,using smaller p,distortions tend to be distributed to a sparse set of vertices,typically in feature regions,thus making most areas less distorted and structures better *** the other hand,using larger p tends to distribute distortions more evenly across the whole *** flexibility is often desirable as it mimics objects made up with different *** specifying varying p over the shape,more flexible control can be *** demonstrate the effectiveness of the proposed algorithm with various examples.

关键词： shape deformation Lp norm geometric modeling

Characteristic analysis for a polynomial-like iterative equation

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Chinese Science Bulletin 1998年第3期43卷 192-196页

作者： Janusz Matkowski 1 and zhang Weinian 2.1. {2. of Mathematics, Technical university, 43_300 Bielsko_Biala, Poland 2. {2. of Mathematics, Sichuan Union university, Chengdu 610064, china department of Mathematics Technical University Bielsko-Biala Poland department of Mathematics Sichuan Union University Chengdu China

In the light of Euler’s idea for differential equations,a polynomial_like n _order iterative equation is discussed through analyzing its characteristic polynomial. An unproved result is verified rigorously for the fi... 详细信息

关键词： iterative dynamics functional equation characteristic.

The Fuzzy Cluster Analysis in Identification of Key Temperatures in Machine Tool

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厦门大学学报（自然科学版） 2002年第S1期41卷 88-89页

作者： ZHAO Da-quan 1, ZHENG Li 1, XIANG Wei-hong 1, LI Kang 1, LIU Da-cheng 1, zhang Bo-peng 2.(1. department of Industrial Engineering, {2., 2. department of Precision Instruments and Mechanology, {2., B eijing 100084, china)

The thermal-induced error is a very important sour ce of machining errors of machine tools. To compensate the thermal-induced machin ing errors, a relationship model between the thermal field and deformations was needed. The relationship can be deduced by virtual of FEM (Finite Element Method ), ANN (Artificial Neural Network) or MRA (Multiple Regression Analysis). MR A is on the basis of a total understanding of the temperature distribution of th e machine tool. Although the more the temperatures measured are, the more accura te the MRA is, too more temperatures will hinder the analysis calculation. So it is necessary to identify the key temperatures of the machine tool. The selectio n of key temperatures decides the efficiency and precision of MRA. Because of th e complexities and multi-input and multi-output structure of the relationships , the exact quantitative portions as well as the unclear portions must be taken into consideration together to improve the identification of key temperatures. I n this paper, a fuzzy cluster analysis was used to select the key temperatures. The substance of identifying the key temperatures is to group all temperatures b y their relativity, and then to select a temperature from each group as the repr esentation. A fuzzy cluster analysis can uncover the relationships between t he thermal field and deformations more truly and thoroughly. A fuzzy cluster ana lysis is the cluster analysis based on fuzzy sets. Given U={u i|i=0,...,N}, in which u i is the temperature measured, a fuzzy matrix R can be obta ined. The transfer close package t(R) can be deduced from R. A fuzzy clu ster of U then conducts on the basis of t(R). Based on the fuzzy cluster analysis discussed above, this paper identified the k ey temperatures of a horizontal machining center. The number of the temperatures measured was reduced to 4 from 32. and then the multiple regression relationshi p models between the 4 temperatures and the thermal deformations of the spind

关键词： The Fuzzy Cluster Analysis in Identification of Key Temperatures in Machine Tool

Study on lithogeochemistry of Middle Jurassic basalts from southern china represented by the Fankeng basalts from Yongding of Fujian Province

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Science china Earth sciences 2006年第10期49卷 1020-1031页

作者： ZHOU Jincheng1,2. JIANG Shaoyong1,2. WANG Xiaolei1,2. YANG Jinghong 1,2.& zhang Mengqun 3 1. State Key Laboratory of Mineral Deposit Research, Nanjing university, Nanjing 2.0093, {2. 2. department of Earth sciences, Nanjing university, Nanjing 2.0093, {2. 3. Modern Analysis Center, Nanjing university, Nanjing 2.0093, {2. 1. State Key Laboratory of Mineral Deposit Research Nanjing University Nanjing 210093 China 2. department of Earth sciences Nanjing University Nanjing 210093 China 3. Modern Analysis Center Nanjing University Nanjing 210093 China

There exists an E-W trending Middle Jurassic volcanic zone in southern china. The Fankeng basalts in the Yongding basin of Fujian Province are considered to be a typical example. The Fankeng basalts have TiO2.contents in the range of 1.92.-3.2.%. They are classified as high-Ti basalts. They also have higher total Fe (averaging FeO* = 11.09%). The Middle Jurassic Fankeng basalts from southwestern Fujian have obvious distinctive lithogeochemical features from early Cre- taceous basalts from southeastern coast of china. They have higher HFSE, such as Th, Nb, Ta, Zr and Ti. Their element ratios related with HFSE, such as Zr/Ba, La/Nb, La/Ta ,Zr/Y, Ti/Y, Ba/Nb, K/Ti and Rb/Zr are similar to those of OIB. The most samples have ε Nd(T) of-0.70-0.2., which are near chondrite. Some samples have higher ε Nd(T) of ***, these basaltic magmas might be derived from depleted asthenospheric mantle. The lithogeochemical characteristics of the Fankeng basalts may be caused by interaction between asthenosphere and lithosphere at the time. The (Early-) Middle Jurassic basalts and gabbros from southeastern Hunan, southern Jiangxi and northern Guangdong provinces show similar geochemical features to those of the Fankeng basalts from the Yongding of Fujian. Occurrence of these OIB-type basalts in the area may be regarded as the petrological mark of upwelling of asthenosphere at the time. Upwelling of asthenosphere has led to tectonic extension and the formation of rifted basin in the area.

关键词： interaction between asthenosphere and lithosphere, lithogeochemistry, basalts, Middle Jurassic, southern china.

Environmental records of lacustrine sediments in different time scales:Sediment grain size as an example

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Science china Earth sciences 2004年第10期47卷 954-960页

作者： CHEN Jing’an1, WAN Guojiang1, David Dian zhang2. zhang Feng1 & HUANG Ronggui1 1. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of {2., Guiyang 550002. china 2. department of Geography and Geology, university of Hong Kong, Pokfulam Road, Hong Kong, china 1. State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences 550002 Guiyang China 2. department of Geography and Geology University of Hong Kong Pokfulam Road Hong Kong China

Sediment grain size is a conventional proxy of climatic changes. Larger sediment grain size is often interpreted to indicate dry climate during lower lake level while smaller sedi- ment grain size implies wet climate during higher lake level. Through detailed study on sediment grain sizes in Lake Erhai and Lake Chenghai, this paper reveals the different indication signifi- cances of sediment grain sizes in different time scales, different resolution investigations. For long time-scale and low resolution (102. or 103a) studies, larger sediment grain size indicates lower lake level, smaller lake area and drier climate while smaller sediment grain size indicates higher lake level, larger lake area and wetter climate. For short time-scale and high resolution (a or 10a) studies, larger sediment grain size reflects more rainfall and wetter climate while smaller sediment grain size reflects less rainfall and drier climate. Environmental information revealed by lacustrine sediment records is often different in different time scales because of the variance of sedimentation resolution, sampling resolution and dating precision. Therefore, paleoclimate im- plications of environmental proxies in long time-scale and low resolution investigations could not be mechanically applied to short time-scale and high resolution studies. Only after synthetically analyzing the influence manner and extent of all factors on the sediment records in different time scales, can credible conclusions be obtained.

关键词： lacustrine sediment, environmental record, grain size, time scale.