One-Way Traffic synthetic assessing can not only determine the assessment method, but can also provide an opportunity for further study of road systems. Comparing three Road Traffic Planning methods, which are Value A...One-Way Traffic synthetic assessing can not only determine the assessment method, but can also provide an opportunity for further study of road systems. Comparing three Road Traffic Planning methods, which are Value Analysis method, Simple Array method and Step Analysis method, this paper concludes that Simple Array method has one prominent merit, avoiding the complicated relationship of various factors and simplifying the complex problem. Therefore Simple Array method is firstly presented in this paper to be the assessing measure to assess the One-Way Traffic Planning project. Although this assessing method cannot wholly give way to man’s will, through consistently testing on qualitative factors and with the decision-making results of a multi-program, this method is still an effective method. Using an example of Harbin One-Way Traffic planning, with seven assessing indexes including economic benefit index, Simple Array method is applied to synthetically assessing the program. This fully reflects the general function of One-Way Traffic planning program and objectively evaluates the program. It also proves that, as the method of One-Way Traffic synthetic assessing, Simple Array method is rational and practical.展开更多
An experimental study on intensifying osmotic dehydration was carried out ina state of nature and with acoustic cavitation of different cavitating intensity (0.5A, 0.7A and0.9A) respectively, in which the material is ...An experimental study on intensifying osmotic dehydration was carried out ina state of nature and with acoustic cavitation of different cavitating intensity (0.5A, 0.7A and0.9A) respectively, in which the material is apple slice of 5mm thickness. The result showed thatacoustic cavitation remarkably enhanced the osmotic dehydration, and the water loss was acceleratedwith the increase of cavitating intensity. The water diffusivity coefficients ranged from1.8x10^(-10)m^2·s^(-1) at 0.5A to 2.6x10^(-10)m^2·s^(-1) at 0.9A, and solute diffusivitycoefficients ranged from 3.5x10^(-11) m^2·s^(-1) at 0.5A to 4.6X10^(-11)m^2·s^(-1) at 0.9A. On thebasis of experiments, a mathematical model was established about mass transfer during osmoticdehydration, and the numerical simulation was carried out. The calculated results agree well withexperimental data, and represent the rule of mass transfer during osmotic dehydration intensified byacoustic cavitation.展开更多
Based on the membrane-based absorption experiment of CO2 into water, shell-side flow distribution and mass transfer in a randomly packed hollow fiber module have been analyzed using subchannel model and unsteady penet...Based on the membrane-based absorption experiment of CO2 into water, shell-side flow distribution and mass transfer in a randomly packed hollow fiber module have been analyzed using subchannel model and unsteady penetration mass transfer theory. The cross section of module is subdivided into many small cells which contains only one hollow-fiber. The cross sectional area distribution of these cells is presented by the normal probability density distribution function. It has been obtained that there was a most serious non-ideal flow in shell side at moderate mean packing density, and the large amount of fluid flowed and transferred mass through a small number of large voids. Thus mass transfer process is dominated by the fluid through the larger void area. The mass transfer process in each cell is described by the unsteady penetration theory. The overall mass transfer coefficient equals to the probability addition of the mean mass transfer coefficient in each cell. The comparisons of the values calculated by the model established with the empirical correlations and the experimental data of this work have been done.The predicted overall mass transfer coefficients are in good agreement with experimental data.展开更多
This paper attempts to explore a new avenue of urban small-regional population estimation by remote sensing technology, creatively and comprehensively for the first time using a residence count method, area (density) ...This paper attempts to explore a new avenue of urban small-regional population estimation by remote sensing technology, creatively and comprehensively for the first time using a residence count method, area (density) method and model method, incorporating the application experience of American scholars in the light of the state of our country. Firstly, the author proposes theoretical basis for population estimation by remote sensing, on the basis of analysing and evaluating the history and state quo of application of methods of population estimation by remote sensing. Secondly, two original types of mathematical models of population estimation are developed on the basis of remote sensing data, taking Tianjin City as an example. By both of the mathematical models the regional population may be estimated from remote sensing variable values with high accuracy. The number of the independent variables in the latter model is somewhat smaller and the collection of remote sensing data is somewhat easier, but the deviation is a little larger. Finally, some viewpoints on the principled problems about the practical application of remote sensing to population estimation are put forward.展开更多
The application level of mathematics in each science discipline signs the level of development of this science. With the advancement of science and technology, especially the rapid development of computer technology, ...The application level of mathematics in each science discipline signs the level of development of this science. With the advancement of science and technology, especially the rapid development of computer technology, mathematics has permeated from natural scientific technology to agricultural construction, from economic activities to all areas of social life. Generally, when the actual problem requires us to provide quantitative results of analysis, forecasting, decision making, control and other aspects for real object under study, we are often inseparable from the application of mathematics. Mathematical modeling is the key to this process, whose purpose is to make mathematics applied to social and social services, and using mathematics to solve practical problems is through mathematical models. When using mathematical methods to solve some practical problems, we usually first transfer practical problems into mathematical language, and then abstract them into a mathematical model.展开更多
The cleaning parameters affecting cleaning rate using pure waterjets to clean road surface was researched. A mathematical model for predicting cleaning rate was established using fuzzy mathematical method. A fuzzy rul...The cleaning parameters affecting cleaning rate using pure waterjets to clean road surface was researched. A mathematical model for predicting cleaning rate was established using fuzzy mathematical method. A fuzzy rule base character-izing the relationship between input and output parameters was built through experiments. The prediction of cleaning rate was achieved under the condition of given input parameters by rule-based fuzzy reasoning. The prediction results were analyzed through experimental verification.展开更多
Given the actual working of a fully mechanized plough at a mining face, we have proposed a formula for running constraints between powered supports and a coal plough under assumed geological conditions of the coal fac...Given the actual working of a fully mechanized plough at a mining face, we have proposed a formula for running constraints between powered supports and a coal plough under assumed geological conditions of the coal face and, on this basis, established an automatic control model of powered supports for the coal plough face. We introduced the working principle of the powered support control system of the plough at the mining face. We established three advanced characteristics of this control system： response speed, reliability and easy maintenance of the system. As well, we briefly introduced, the principal function of primary and subordinate controllers and the realization of the communication system by a Single Bus. Ten controllers were constructed and tested in our laboratorium. The results show that the control model is practical and meets actual conditions. It provides a theoretical basis for designing a comouter control system for a oowered support system of a plough at a mining face.展开更多
Based on the stress-algebraic model, the turbulent buoyant jet with variable density was studied by the relation between density and concentration. A simple expression for buoyancy coefficient was proposed. The govern...Based on the stress-algebraic model, the turbulent buoyant jet with variable density was studied by the relation between density and concentration. A simple expression for buoyancy coefficient was proposed. The governing equations of turbulent buoyant jet with variable density were closed by introducing the expression of β and the relation between density and concentration. Numerical results for the jet axis with density difference agree well with experimental ones. By finite volume method, the 2 - D vertical jet＇s flow field with different jet angles was studied. The analysis of the relation among the vortex center, the position of separation point and jet angles shows that the circumfluenee field is the largest when the jet angle is 90°. The area turbulent kinetic energy ka is proposed and the relationship between mixing intensity and jet angles is analyzed based on it. Results show that the jet angle of is the optimum condition for jet water mixing with environment water;and the reduced rate of difference between the centerline density of jet and the density of ambient water is the largest at the jet angle of 90°.展开更多
Plunge milling is a high-speed machining way and the cutter is fed in the direction of the Z axis, which is used to remove excess material rapidly in roughing operations. In this paper, the orthogonal cutting theory w...Plunge milling is a high-speed machining way and the cutter is fed in the direction of the Z axis, which is used to remove excess material rapidly in roughing operations. In this paper, the orthogonal cutting theory was used to study the plunge milling of LY12 alloy. A mathematic model for cutting force in plunge milling was established, and the milling process was simulated by using Matlab. It is found that the single tooth cutting experimental result is unstable because of unsymmetrical single tooth in the milling process, which leads to the difference between the simulation and experimental results. The trend of multiple teeth cutting experimental result is similar to that of the simulation result; however, the peak values in the experimental result are different, which is caused by the error of cutter’s position, and the error of peak value is less than 10%.展开更多
This paper introduces the main methods and steps of modeling principle by ordinary differential equations, and is used to explore the differential equation model to solve some practical problems, some features of the ...This paper introduces the main methods and steps of modeling principle by ordinary differential equations, and is used to explore the differential equation model to solve some practical problems, some features of the related problems. With the development of science and technology and production practice, differential equation is more closely connected with other subjects, and a mathematical model for some practical problems of good.展开更多
文摘One-Way Traffic synthetic assessing can not only determine the assessment method, but can also provide an opportunity for further study of road systems. Comparing three Road Traffic Planning methods, which are Value Analysis method, Simple Array method and Step Analysis method, this paper concludes that Simple Array method has one prominent merit, avoiding the complicated relationship of various factors and simplifying the complex problem. Therefore Simple Array method is firstly presented in this paper to be the assessing measure to assess the One-Way Traffic Planning project. Although this assessing method cannot wholly give way to man’s will, through consistently testing on qualitative factors and with the decision-making results of a multi-program, this method is still an effective method. Using an example of Harbin One-Way Traffic planning, with seven assessing indexes including economic benefit index, Simple Array method is applied to synthetically assessing the program. This fully reflects the general function of One-Way Traffic planning program and objectively evaluates the program. It also proves that, as the method of One-Way Traffic synthetic assessing, Simple Array method is rational and practical.
文摘An experimental study on intensifying osmotic dehydration was carried out ina state of nature and with acoustic cavitation of different cavitating intensity (0.5A, 0.7A and0.9A) respectively, in which the material is apple slice of 5mm thickness. The result showed thatacoustic cavitation remarkably enhanced the osmotic dehydration, and the water loss was acceleratedwith the increase of cavitating intensity. The water diffusivity coefficients ranged from1.8x10^(-10)m^2·s^(-1) at 0.5A to 2.6x10^(-10)m^2·s^(-1) at 0.9A, and solute diffusivitycoefficients ranged from 3.5x10^(-11) m^2·s^(-1) at 0.5A to 4.6X10^(-11)m^2·s^(-1) at 0.9A. On thebasis of experiments, a mathematical model was established about mass transfer during osmoticdehydration, and the numerical simulation was carried out. The calculated results agree well withexperimental data, and represent the rule of mass transfer during osmotic dehydration intensified byacoustic cavitation.
基金Supported by the Hi-Tech. Research and Development Program of China (863) (2002AA649280, 2002AA304030), National Natural Science Foundation of China (No. 20206002), Beijing NOVA program (H013610250112), University Postdoctrate Research Foundation of Chin
文摘Based on the membrane-based absorption experiment of CO2 into water, shell-side flow distribution and mass transfer in a randomly packed hollow fiber module have been analyzed using subchannel model and unsteady penetration mass transfer theory. The cross section of module is subdivided into many small cells which contains only one hollow-fiber. The cross sectional area distribution of these cells is presented by the normal probability density distribution function. It has been obtained that there was a most serious non-ideal flow in shell side at moderate mean packing density, and the large amount of fluid flowed and transferred mass through a small number of large voids. Thus mass transfer process is dominated by the fluid through the larger void area. The mass transfer process in each cell is described by the unsteady penetration theory. The overall mass transfer coefficient equals to the probability addition of the mean mass transfer coefficient in each cell. The comparisons of the values calculated by the model established with the empirical correlations and the experimental data of this work have been done.The predicted overall mass transfer coefficients are in good agreement with experimental data.
文摘This paper attempts to explore a new avenue of urban small-regional population estimation by remote sensing technology, creatively and comprehensively for the first time using a residence count method, area (density) method and model method, incorporating the application experience of American scholars in the light of the state of our country. Firstly, the author proposes theoretical basis for population estimation by remote sensing, on the basis of analysing and evaluating the history and state quo of application of methods of population estimation by remote sensing. Secondly, two original types of mathematical models of population estimation are developed on the basis of remote sensing data, taking Tianjin City as an example. By both of the mathematical models the regional population may be estimated from remote sensing variable values with high accuracy. The number of the independent variables in the latter model is somewhat smaller and the collection of remote sensing data is somewhat easier, but the deviation is a little larger. Finally, some viewpoints on the principled problems about the practical application of remote sensing to population estimation are put forward.
文摘The application level of mathematics in each science discipline signs the level of development of this science. With the advancement of science and technology, especially the rapid development of computer technology, mathematics has permeated from natural scientific technology to agricultural construction, from economic activities to all areas of social life. Generally, when the actual problem requires us to provide quantitative results of analysis, forecasting, decision making, control and other aspects for real object under study, we are often inseparable from the application of mathematics. Mathematical modeling is the key to this process, whose purpose is to make mathematics applied to social and social services, and using mathematics to solve practical problems is through mathematical models. When using mathematical methods to solve some practical problems, we usually first transfer practical problems into mathematical language, and then abstract them into a mathematical model.
文摘The cleaning parameters affecting cleaning rate using pure waterjets to clean road surface was researched. A mathematical model for predicting cleaning rate was established using fuzzy mathematical method. A fuzzy rule base character-izing the relationship between input and output parameters was built through experiments. The prediction of cleaning rate was achieved under the condition of given input parameters by rule-based fuzzy reasoning. The prediction results were analyzed through experimental verification.
基金Project 104030 supported by the Ministry of Education of the People’s Republic of China
文摘Given the actual working of a fully mechanized plough at a mining face, we have proposed a formula for running constraints between powered supports and a coal plough under assumed geological conditions of the coal face and, on this basis, established an automatic control model of powered supports for the coal plough face. We introduced the working principle of the powered support control system of the plough at the mining face. We established three advanced characteristics of this control system： response speed, reliability and easy maintenance of the system. As well, we briefly introduced, the principal function of primary and subordinate controllers and the realization of the communication system by a Single Bus. Ten controllers were constructed and tested in our laboratorium. The results show that the control model is practical and meets actual conditions. It provides a theoretical basis for designing a comouter control system for a oowered support system of a plough at a mining face.
基金the Natural Science Foundation of Liaoning Province(Grant No.20032115)
文摘Based on the stress-algebraic model, the turbulent buoyant jet with variable density was studied by the relation between density and concentration. A simple expression for buoyancy coefficient was proposed. The governing equations of turbulent buoyant jet with variable density were closed by introducing the expression of β and the relation between density and concentration. Numerical results for the jet axis with density difference agree well with experimental ones. By finite volume method, the 2 - D vertical jet＇s flow field with different jet angles was studied. The analysis of the relation among the vortex center, the position of separation point and jet angles shows that the circumfluenee field is the largest when the jet angle is 90°. The area turbulent kinetic energy ka is proposed and the relationship between mixing intensity and jet angles is analyzed based on it. Results show that the jet angle of is the optimum condition for jet water mixing with environment water;and the reduced rate of difference between the centerline density of jet and the density of ambient water is the largest at the jet angle of 90°.
基金Supported by Advanced Manufacturing Technology-Key Laboratory of Beijing Municipality Project(No.10200531)Tianjin University-Kenna-metal Joint Project+1 种基金Young Teacher Foundation of Tianjin UniversityApparatus Foundation of Tianjin University.
文摘Plunge milling is a high-speed machining way and the cutter is fed in the direction of the Z axis, which is used to remove excess material rapidly in roughing operations. In this paper, the orthogonal cutting theory was used to study the plunge milling of LY12 alloy. A mathematic model for cutting force in plunge milling was established, and the milling process was simulated by using Matlab. It is found that the single tooth cutting experimental result is unstable because of unsymmetrical single tooth in the milling process, which leads to the difference between the simulation and experimental results. The trend of multiple teeth cutting experimental result is similar to that of the simulation result; however, the peak values in the experimental result are different, which is caused by the error of cutter’s position, and the error of peak value is less than 10%.
文摘This paper introduces the main methods and steps of modeling principle by ordinary differential equations, and is used to explore the differential equation model to solve some practical problems, some features of the related problems. With the development of science and technology and production practice, differential equation is more closely connected with other subjects, and a mathematical model for some practical problems of good.
