检索结果-南通市图书馆

EXTRACTION KINETICS,SYNERGISTIC EFFECTS AND INTERFACIAL CHEMISTRY FOR D_2 EHPA MPA-Fe^(3+) MIXED EXTRACTION SYSTEM

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1993年第12期6卷 405-410页

作者： YU Jingfen LIU Difei tsinghua university,beijing,china professor,Dept.of Chemical engineering,tsinghua university,beijing 100084,china tsinghua Univ Beijing China

The thermodynamics of micella formation,interfacial characteristics,synergistic effects and interfacial kinetics for synergistic extraction system D_2 EHPA-MPA-Fe^(3+) have been *** was found that D_2EHPA in the mixed system strongly exhibits the effect on the micella formation thermodynamics and interracial characteristics of *** ther- modynamic parameters for constants of micelles formation(K_m).free energies of micelles formation(ΔG_m)and critical micella concentrations(CMC)were *** inter- facial adsorption behaviour of D_2EHPA is opposite to that of *** emulsification for single MPA and the mixed system was *** synergistic effects were found in this mixed extraction *** is proved that the process of the Fe^(3+) extraction for non-mixed extraction system is controlled by chemical reaction and the controlling reaction occurs at the interface.

关键词： interfacial chemistry synergistic effect Fe^(3+) extraction kinetics

NUMERICAL STUDY OF TURBULENT SWIRLING FLOW IN COMBUSTOR

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 1996年第1期9卷 6-12页

作者： Fu Song(department of engineering mechanics, tsinghua university, beijing, china, 100083) department of engineering mechanics Tsinghua University Beijing 100083 China

Numerical computation of turbulent strongly-swirling flows in combustors is presented. Turbulence models examined are based on the transport equations of the Reynolds stresses, i.e., the second moment closures. The particular flows in question include confined as well as free swirling situations where the swirl number is large. It is indicated that the second-moment closure models offer an effective means for predicting strongly swirling flows. In particular, the isotropization of production and convection (IPC) model gives the best overall performance. The study directly serves for the improvement of combustor design.

关键词： combustion chambers swirling turbulence Reynolds stress numerical analysis

Non-linear Identification Based on the Method of Gauss Functions

在线全文

学校读者我要写书评

暂无评论

Communications in Nonlinear Science and Numerical Simulation 1997年第3期2卷 39-44页

作者： Qing ZHANG & Chongde LU (department of Thermal engineering, tsinghua university ,beijing, 100084) department of Thermal engineering Tsinghua University Beijing 100084 China

ＮｏｎｌｉｎｅａｒＩｄｅｎｔｉｆｉｃａｔｉｏｎＢａｓｅｄｏｎｔｈｅＭｅｔｈｏｄｏｆＧａｕｓＦｕｎｃｔｉｏｎｓ１１ＴｈｅｐａｐｅｒｗａｓｒｅｃｅｉｖｅｄｏｎＪｕｌ．２０ｔｈ，１９９７ＱｉｎｇＺＨＡＮＧ＆Ｃｈｏｎｇｄｅ... 详细信息

ＮｏｎｌｉｎｅａｒＩｄｅｎｔｉｆｉｃａｔｉｏｎＢａｓｅｄｏｎｔｈｅＭｅｔｈｏｄｏｆＧａｕｓＦｕｎｃｔｉｏｎｓ１１ＴｈｅｐａｐｅｒｗａｓｒｅｃｅｉｖｅｄｏｎＪｕｌ．２０ｔｈ，１９９７ＱｉｎｇＺＨＡＮＧ＆ＣｈｏｎｇｄｅＬＵ（ＤｅｐａｒｔｍｅｎｔｏｆＴｈ...

关键词： identification the method of gauss functions whole optimization

Effects of Si Content and the Addition Amount of Al-3B Master Alloy on the Solidification Structures of Hypoeutectic Al-Si Alloys

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2001年第3期20卷 168-173页

作者： Donghui Wang,Jianguo Li, Yankang Zheng, Bingzhe Bai department of Materials Science and engineering, tsinghua university, beijing 100084, china 清华大学北京 100084

Effects of Si content and the addition amount of Al-3B master alloy on the solidification structures of hypoeutectic Al-Si alloys were studied. The addition amounts of the master alloy were 0.2%, 0.4%, 0.7% and 1% (mass fraction, so as the follows), respectively. The Si content of Al-Si binary alloys investigated varied from 1% to 11%. The observation of macrostructures of non-refined samples showed that 3% Si constitutes a transition point at which the minimum grain size can be obtained. It was also found that Al-3B master alloy can shift the transition point towards a higher Si value when its addition amount increases, making this point appear at 4%, 5% and 6% Si as its addition amount increases up to 0.4%, 0.7% and 1%, respectively.

关键词： Al-3B master alloy hypoeutectic Al-Si alloy grain refinement

HIGH TEMPERATURE OXIDATION AND STRUCTURE OF SCALE AND WHISKERS FOR Fe-Ni-Cr SEALING ALLOYS

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1993年第8期6卷 147-150页

作者： DONG Zhili MA Jusheng TANG Xiangyun YOU Liang tsinghua university,beijing,china lecturer department of Materials Science and engineering,tsinghua university,beijing 100084,china tsinghua Univ Beijing China

The oxidation rate,the growth,morphology and structure of oxide scale and whiskers for Fe-Ni-Cr sealing alloys in H_2-H_2O atmosphere at high temperatures have been studied. The growth rate of scale is controlled by *... 详细信息

关键词： oxidation oxide scale oxide whisker Fe-Ni-Cr sealing alloy

To enhance the reproduction of Phanerochaete chrysosporium by adding natural lixiviums in liquid medium

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2003年第6期15卷 808-814页

作者： LIN Gang, WEN Xiang-hua, QIAN Yi (department of Environmental Science and engineering, tsinghua university, beijing 100084, china. department of Environmental Science and engineering Tsinghua University 北京 100084

Great promotion to the reproduction of white rot fungus Phanerochaete chrysosporium by adding natural lixiviums such as from wood, maize core and potato in liquid medium was found in this research. Incubated in the liquid medium contained 10 mg/L glucose as carbon source with natural lixiviums for three days, the production of mycelium pellet reaches more than 80 g/L, which is 5 times more than that of without natural lixiviums. Incubated in the liquid medium contained 5 mg/L glucose as carbon source with natural lixiviums for three days, the production of mycelium pellet can reach 69.5 g/L, while the production in the medium without natural lixiviums is very low. When the liquid medium contained 1—20 g/L glucose as carbon source, the production of mycelium pellet in 3 d can only reach 12.5 g/L to 14.5 g/L. The fungus in the medium with potato lixiviums are easily contaminated by other microorganisms and in the medium with maize core lixiviums are easily bulking, while in the medium with wood lixiviums are neither easily contaminated nor bulking. Medium with wood lixiviums can produce more pellet than other medium, endure contamination and keep better sedimentation capacity. So that, wood lixivium is better additive to the culture of white rot fungi in liquid medium. Addition of the mixture of wood, maize core and potato lixiviums is of advantage to the production of mycelium pellet. The difference of the production in the medium with different amount of wood lixiviums showed little in the first 3 d, while it expanded after 3 d. Wood lixiviums stimulate the growth of P. chrysosporium instead of supply organics which fungi need.

关键词： white rot fungi medium additive

Parameter identification theory of a complex model based on global optimization method

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,mechanics & Astronomy) 2008年第11期51卷 1722-1732页

作者： QU Jie1, JIN QuanLin2 & XU BingYe3 1 College of Automotive engineering, South china university of Technology, Guangzhou 510640, china 2 beijing Research Institute of Mechanical and Electrical Technology, beijing 100083, china 3 department of engineering mechanics, tsinghua university, beijing 100084, china College of Automotive engineering South China University of Technology Guangzhou China beijing Research Institute of Mechanical and Electrical Technology Beijing China department of engineering mechanics Tsinghua University Beijing China

With the development of computer technology and numerical simulation technology, computer aided engineering (CAE) technology has been widely applied to many fields. One of the main obstacles, which hinder the further application of CAE technology, is how to successfully identify the parameters of the selected model. An elementary framework for parameter identification of a complex model is provided in this paper. The framework includes the construction of objective function, the design of the optimization method and the evaluation of the identified results, etc. The parameter identification process is described in this framework, taking the parameter identification of the superplastic constitutive model considering grain growth for Ti-6Al-4V at 927°C as an example. The objective function is the weighted quadratic sums of the difference between the experimental and computational data for the stress-strain relationship and the grain growth relationship; the designed optimization method is a hybrid global optimization method, which is based on the feature of the objective function and incorporates the strengths of genetic algorithm (GA), the Levenberg-Marquardt algorithm and the augmented Gauss-Newton algorithm. The reliability evaluation of parameter identification result is made through the comparison between the calculated and experimental results and between the theoretical values of the parameters and the identified ones.

关键词： constitutive model parameter identification theory inverse analysis global optimization

APPLICATION OF MOLECULAR ORBITAL THEORY TO ANALYSIS OF PHASE STABILITY FOR ALLOYS

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1993年第3期6卷 145-152页

作者： YIN Hong TAO Kun PAN Jinsheng LI Hengde tsinghua university,beijing,china professor.department of Materials Science and engineering,tsinghua university,beijing 100084,china tsinghua Univ Beijing China

The critical _d vahues ( _ ) of the γ/(γ+σ).γ/(γ+μ) and γ/(γ+γ') phase boundaries in some ternar alloy phase diagrams at various temperatures are calculated by averaging the _d values of sererai selected characteristic points at the phase *** equations for the temperature dependence of the critical _d of γ/(γ+σ).γ/(γ+μ) and γ/(γ+γ') phase boundaries are *** accuracy of the analysis is discussed in detail. It is found for the first time that the average value of the bond order _ at the phase boundaries ts also approximatelr a constant and therefore a critical average bond order _ like - can be introduced for the analysts of phase stability

关键词： molecular orbital theory allov phase stabilitv

Maximal regularity of second order delay equations in Banach spaces

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2010年第1期53卷 51-62页

作者： BU ShangQuan ? & FANG Yi department of Mathematical Sciences, tsinghua university, beijing 100084, china department of Mathematical Sciences, tsinghua university, beijing 100084, china department of Mathematical Sciences Tsinghua University Beijing China

We give necessary and sufficient conditions of Lp-maximal regularity(resp.B sp ,q-maximal regularity or F sp ,q-maximal regularity) for the second order delay equations:u″(t)=Au(t) + Gu't + F u t + f(t), t ∈ [0, 2π] with periodic boundary conditions u(0)=u(2π), u′(0)=u′(2π), where A is a closed operator in a Banach space X,F and G are delay operators on Lp([-2π, 0];X)(*** ,q([2π, 0];X) or Fsp,q([-2π, 0;X])).

关键词： maximal regularity second order delay equations Lebesgue-Bochner spaces Besov spaces Triebel-Lizorkin spaces