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Pilot-plant Study of Anoxic-aerobic Membrane Bioreactor (AO-MBR) on the Changes of Membrane Flux under Constant Pressure
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作者 Z.Q. Liu C.P. Wang +1 位作者 J.Y. Wang C. Liu 《Journal of Environmental Science and Engineering》 2010年第3期13-20,共8页
Under a constant pressure, a pilot-plant test was conducted through the use of anoxic-aerobic membrane bioreactor (AO-MBR), and this test operated steadily for 251 days. During the experiment, there were a total of ... Under a constant pressure, a pilot-plant test was conducted through the use of anoxic-aerobic membrane bioreactor (AO-MBR), and this test operated steadily for 251 days. During the experiment, there were a total of four membrane cleaning processes, for the 90th day, the 150th day, the 210th day and the 240th day, respectively (The cleaning cycle was 90 days, 60 days, 60 days and 30 days, respectively). From the initial 33.26 L/m^2.b dropped to 20.03 L/m^2.h after the fourth membrane cleaning, membrane flux reduced to 60.22% of the initial flux. During the 180 thd-210 thd of the experiment, the powdered activated carbon (PAC), the segment size of which is 80-100, was put into anoxic reactor. Membrane flux decreased from 16.02 L/m^2·h to 15.29 L/m^2·h, and then rose to 15.65L/m^2·h. The dosing of PAC had a significant effect on the maintenance of a high membrane flux and extending running time. Before several membrane cleanings, a wire of membrane was intercepted from membrane module. It was found that the membrane surface sediments seemed to the inorganic colloid formed by Fe^2+, Ca^2+ and biofilm formed by some micro-organisms after the membrane surface pollutants were analyzed preliminarily with scanning electron microscopy (SEM). 展开更多
关键词 Anoxic-aerobic membrane bioreactor (AO-MBR) constant pressure membrane fouling membrane flux membrane cleaning cycle.
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STUDY ON AUTOMATIC POLISHING AT CONSTANT PRESSURE INTENSITY
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作者 Zhao Ji(Jilin University of TechnologyKondo T Narahara H Igarashi S Saito kHokkaido University, Japan) 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 1994年第4期296-302,共17页
Through theoretical and experimental researeh about automatic polishing on thecurved surfaces of the moulds, the limitation of the polishing method at constant pressure, whichis adopted widely in the world, is analyse... Through theoretical and experimental researeh about automatic polishing on thecurved surfaces of the moulds, the limitation of the polishing method at constant pressure, whichis adopted widely in the world, is analysed. Based on the analysis, a new polishing method atconstant pressure intensity is proposed, and the corresponding goveming equation and a com-prehensive polishing parameter are given as well. 展开更多
关键词 Mould curved surface Polishing at constant pressure intensity Comprehensive polishing parameter
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Speed of Sound and Ideal-Gas Heat Capacity at Constant Pressure for HFC-125
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作者 张昌 段远源 +1 位作者 王鑫 朱明善 《Tsinghua Science and Technology》 SCIE EI CAS 2001年第5期479-483,共5页
The gaseous speed of sound, the ideal gas heat capacity at constant pressure, and the second Virial coefficient were determined for pentafluoroethane (HFC 125). A total of 49 data points of speed of sound for gas... The gaseous speed of sound, the ideal gas heat capacity at constant pressure, and the second Virial coefficient were determined for pentafluoroethane (HFC 125). A total of 49 data points of speed of sound for gaseous HFC 125 were measured for temperatures from 273 to 313 K and pressures from 32 to 479 kPa with a cylindrical, variable path acoustic interferometer. The ideal gas heat capacity at constant pressure and the second acoustic Virial coefficient were determined over the temperature range from the speed of sound measurements and were correlated as functions of temperature. An analytical expression for the second Virial coefficient derived using the square well intermolecular potential model was compared with the data. 展开更多
关键词 pentafluoroethane (HFC 125) speed of sound ideal gas heat capacity at constant pressure second Virial coefficient
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FOUR WHEELS DRIVEN INDEPENDENTLY BY ONE PUMP DRIVING FOUR HYDRAULIC MOTORS 被引量:3
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作者 WuBaolin QiuLihua WangZhanlin 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2005年第2期232-236,共5页
An improved Narendra model reference adaptive control (MRAC) scheme isproposed to research one variable displacement pump driving four hydraulic variable displacementmotors. This approach not only ensures the underdam... An improved Narendra model reference adaptive control (MRAC) scheme isproposed to research one variable displacement pump driving four hydraulic variable displacementmotors. This approach not only ensures the underdamped and unstable system be global uniformasymptotic stability, but also has good robustness in these aspects of modeling uncertainty,pressure fluctuation of constant pressure network, and disturbance from external load, which alsoupgrades the rapidity of system response so as to make controlled system with nicer dynamic quality.The scheme of one pump driving four motors can meet the demand on off-road mobility of engineeringvehicles and armored cars. A proof of stability about improved Narendra MRAC scheme is also given. 展开更多
关键词 constant pressure network Rotational speed control Model reference adaptivecontrol(MRAC) Strict positive realness Global uniform stability
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Studies of Thermodynamic Properties and Relative Stability of Polybrominated Xanthones by Density Functional Theory 被引量:3
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作者 单刚 李秀菊 +1 位作者 王遵尧 杨郭英 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2010年第2期225-232,共8页
The thermodynamic properties of xanthone(XTH) and 135 polybrominated xanthones(PBXTHs) in the standard state have been calculated at the B3LYP/6-31G* level using Gaussian 03 program.The isodesmic reactions were d... The thermodynamic properties of xanthone(XTH) and 135 polybrominated xanthones(PBXTHs) in the standard state have been calculated at the B3LYP/6-31G* level using Gaussian 03 program.The isodesmic reactions were designed to calculate the standard enthalpy of formation(△fHθ) and standard free energy of formation(△fGθ) of PBXTH congeners.The relations of these thermodynamic parameters with the number and position of Br atom substitution(NPBS) were discussed,and it was found that there exist high correlation between thermodynamic parameters(entropy(Sθ),△fHθ and △fGθ) and NPBS.According to the relative magnitude of their △fGθ,the relative stability order of PBXTH congeners was theoretically proposed.The relative rate constants of formation reactions of PBXTH congeners were calculated,Moreover,the values of molar heat capacity at constant pressure(Cp,m) from 200 to 1000 K for PBXTH congeners were also calculated,and the temperature dependence relation of them was obtained,suggesting very good relationships between Cp,m and temperature(T,T^1 and T^2) for almost all PBXTH congeners. 展开更多
关键词 polybrominated xanthone the number and position of Br atom substitution(NPBS) thermodynamic property relative stability molar heat capacity at constant pressure(Cp m)
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Lagrangian cell-centered conservative scheme 被引量:1
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作者 葛全文 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2012年第10期1329-1350,共22页
This paper presents a Lagrangian cell-centered conservative gas dynamics scheme. The piecewise constant pressures of cells arising from the current time sub-cell densities and the current time isentropic speed of soun... This paper presents a Lagrangian cell-centered conservative gas dynamics scheme. The piecewise constant pressures of cells arising from the current time sub-cell densities and the current time isentropic speed of sound are introduced. Multipling the initial cell density by the initial sub-cell volumes obtains the sub-cell Lagrangian masses, and dividing the masses by the current time sub-cell volumes gets the current time sub- cell densities. By the current time piecewise constant pressures of cells, a scheme that conserves the momentum and total energy is constructed. The vertex velocities and the numerical fluxes through the cell interfaces are computed in a consistent manner due to an original solver located at the nodes. The numerical tests are presented, which are representative for compressible flows and demonstrate the robustness and accuracy of the Lagrangian cell-centered conservative scheme. 展开更多
关键词 sub-cell force Lagrange cell-centered scheme Lagrangian cell-centeredconservative gas dynamics scheme piecewise constant pressure of cell
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DFT Study on Some Properties of Polybrominated Phenoxathiin 10-Oxides
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作者 曲瑞娟 石佳奇 +2 位作者 程润秋 杨曦 王遵尧 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2011年第10期1501-1508,共8页
With the B3LYP calculation method of density functional theory(DFT)and the 6-31G* basis set,full optimization calculation was made for phenoxathiin10-oxide(PTO)and 135 polybromine phenoxathiin 10-oxides(PBPTOs)... With the B3LYP calculation method of density functional theory(DFT)and the 6-31G* basis set,full optimization calculation was made for phenoxathiin10-oxide(PTO)and 135 polybromine phenoxathiin 10-oxides(PBPTOs)with the Gaussian 03 program and molar heat capacity in constant volume(CVθ)value of each molecule in the standard state was obtained.The relation between CVθ and the substitution position and number of bromine atom(NPBS)was studied,and the results indicated good correlation(R2 = 1.000)between CVθ and NPBS of PBPTO compounds.Based on the output file of Gaussian 03 program,molar heat capacity at constant pressure(Cp,m)of PBPTO compounds from 200 to 1,000 K was calculated with the statistical thermodynamics program,and the correlation equation between Cp,m and temperature(T,T-1 and T-2)was obtained with the least-squares method,and the correlation coefficient of the correlation equation(R2)was 1.000.In addition,based on the partition function of each molecule calculated by vibration analysis,the relative rate constant of formation of each molecule was calculated. 展开更多
关键词 PBPTOs substitution position and number of bromine atom(NPBS) molar heat capacity in constant volume(CVθ) molar heat capacity at constant pressure(Cp m) relative rate constant
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Technology of load-sensitivity used in the hydraulic system of an all-hydraulic core rig 被引量:6
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作者 XIN De-zhong CHEN Song-ling WANG Qing-feng 《Journal of Coal Science & Engineering(China)》 2009年第3期318-323,共6页
The existing hydraulic system always have problems of temperature rise,runningstability and anti-interference of the implementation components,reliability of hydrauliccomponents,maintenance difficulties,and other issu... The existing hydraulic system always have problems of temperature rise,runningstability and anti-interference of the implementation components,reliability of hydrauliccomponents,maintenance difficulties,and other issues.With high efficiency,energysaving,reliability,easy operating,stable running,anti-interference ability,and other advantages,the load-sensitive hydraulic system is more suitable for coal mine all-hydrauliccore rig.Therefore,for the technical development of the coal mine all-hydraulic core rig,the load-sensitive technology employed by the rig should be of great significance. 展开更多
关键词 all-hydraulic core rig load-sensitivity pressure constant contro
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Fatigue Properties of Plain Concrete Under Triaxial Compressive Cyclic Loading 被引量:1
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作者 曹伟 宋玉普 刘海成 《海洋工程:英文版》 2004年第3期457-468,共12页
Experiments were made on plain concrete subjected to triaxial static loading and constant amplitude compressive fatigue loading with a constant lateral pressure in two directions. The initial confining pressure was 0... Experiments were made on plain concrete subjected to triaxial static loading and constant amplitude compressive fatigue loading with a constant lateral pressure in two directions. The initial confining pressure was 0, 0.1 f c , 0.25 f c and 0.4 f c , respectively, for the static test, and 0.1 f c and 0.25 f c for the fatigue test. Based on the triaxial compressive constitutive behavior of concrete, the inflexion of confining pressure evolution was chosen to be the fatigue damage criterion during the test. The rule of evolution of longitudinal maximum and minimum strains, longitudinal cyclic modulus and damage were recorded and analyzed. According to the Fardis Chen criterion model and the concept of equivalent fatigue life and equivalent stress level, a unified S N curve for multi axial compressive fatigue loading was proposed. Thus, the fatigue strength factors for different fatigue loading cases can be obtained. The present investigation provides information for the fatigue design of concrete structures. 展开更多
关键词 concrete triaxial compressive fatigue loading with constant lateral pressure constant amplitude damage fatigue strength
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