We establish the construction theory of function based upon a local field Kp as underlying space. By virture of the concept of pseudo-differential operator, we introduce ＂fractal calculus＂ （or, p-type calculus, or,...We establish the construction theory of function based upon a local field Kp as underlying space. By virture of the concept of pseudo-differential operator, we introduce ＂fractal calculus＂ （or, p-type calculus, or, Gibbs-Butzer calculus）. Then, show the Jackson direct approximation theorems, Bermstein inverse approximation theorems and the equivalent approximation theorems for compact group D（C Kp） and locally compact group Kp^＋-（= Kp）, so that the foundation of construction theory of function on local fields is established. Moreover, the Jackson type, Bernstein type, and equivalent approximation theorems on the HOlder-type space C^σ（Kp）, σ 〉0, are proved; then the equivalent approximation theorem on Sobolev-type space Wr（Kp）, σ≥0, 1≤r 〈∞, is shown.展开更多
The generative operations concerning the transformation between the active and the passive convert successively from PS rules, T-rules, D-structure, NP preposing and postposing, X-bar analysis, to case theory, governm...The generative operations concerning the transformation between the active and the passive convert successively from PS rules, T-rules, D-structure, NP preposing and postposing, X-bar analysis, to case theory, government, checking theory and head movement. The development of the passive construct mirrors the trend of the progress of Chomskyan theory, evolving from the rule motivations to the principle motivations. The giant leap between the phases of the generative grammar has aroused great curiosity among the scholars and learners of syntax. In this paper, the author will explore the tacit strategy underlying the module changes of TG from the perspective of cognitive science.展开更多
Although human beings have come to understand and utilize coal for a very long history, no theoretical breakthrough in the study of coal structure has been made, which still needs continuous efforts of coal chemical w...Although human beings have come to understand and utilize coal for a very long history, no theoretical breakthrough in the study of coal structure has been made, which still needs continuous efforts of coal chemical workers. Based on the viewpoint of ‘vague/clear', the species classification and accurate analysis on coal were conducted by using the natural clustering all-component separation method. A more systematic and detailed coal embedded structure model theory which is suitable for coal of all ranks was developed from the previous one and a more complete theoretical system about the component and structure of coal was constructed. The whole establishment process of the theory was summarized and some of the main support data and analysis test results, including TEM, AFM, FTIR, GC/MS, MALDI/TOF/MS, DART/MSD, fractal analysis and so on were provided. The coal embedded structure theory fully considers both the identity and the particularity of all-rank coal, reflects the coal component and structure in the full range of coal rank, solves the systematic cognitive problem of coal component and structure on macro and micro level, and provides a valuable and meaningful theoretical approach for the coal processing and conversion technology.展开更多
Construction grammar attempts to reveal the nature, structure, and functions of language. As a theoretical system of language based on cognitive linguistics, construction grammar is a reaction and thus a contrast to t...Construction grammar attempts to reveal the nature, structure, and functions of language. As a theoretical system of language based on cognitive linguistics, construction grammar is a reaction and thus a contrast to the traditional generative grammar. This paper tries to outline the major propositions of construction grammar and construction theory, analyses the significance of constructions and their relations to second language acquisition （SLA） and the routes of construction acquisition in SLA, plus the orientations in research on the relations between construction acquisition and SLA.展开更多
“Form-meaning pair”is not a distinctive feature of constructions,but a universal feature of all things.A construction must be a structure.Morphemes are the smallest sound-meaning assemblies,but they only represent a...“Form-meaning pair”is not a distinctive feature of constructions,but a universal feature of all things.A construction must be a structure.Morphemes are the smallest sound-meaning assemblies,but they only represent a symbolic relationship which has no internal structure;thus,they are not constructions.In addition,if morphemes are also treated as constructions,there is a problem of“heterogeneity”in understanding the“form”of constructions.As to the rising“constructionist”and the traditional“atomist”dichotomy,we feel the“constructionist”approach complies better with the actual linguistic life.Construction Grammar leads people to pay close attention to the integrity of constructions and the cognitive mechanisms behind linguistic facts.Therefore,it is of great value both theoretically and practically.However,since Construction Grammar has not yet displayed a distinct value in terms of methodology,we must be careful not to overrate it or overestimate it.展开更多
The emergence and development of constructal theory,which has been a new discipline branch to research sorts of structures in nature and engineering,are reviewed.The core of the constructal theory is that various shap...The emergence and development of constructal theory,which has been a new discipline branch to research sorts of structures in nature and engineering,are reviewed.The core of the constructal theory is that various shapes and structures of the matters in nature are generated from the tendency to obtain optimal performance.Constructal theory and its application are summarized,from disciplines such as heat,mechanism,fluid flow,electricity,magnetism and chemistry,to life and non-life systems in nature.展开更多
Thermal designs for microchannel heat sinks with laminar flow are conducted numerically by combining constructal theory and entransy theory.Three types of 3-D circular disc heat sink models,i.e.without collection micr...Thermal designs for microchannel heat sinks with laminar flow are conducted numerically by combining constructal theory and entransy theory.Three types of 3-D circular disc heat sink models,i.e.without collection microchannels,with center collection microchannels,and with edge collection microchannels,are established respectively.Compared with the entransy equivalent thermal resistances of circular disc heat sink without collection microchannels and circular disc heat sink with edge collection microchannels,that of circular disc heat sink with center collection microchannels is the minimum,so the overall heat transfer performance of circular disc heat sink with center collection microchannels has obvious advantages.Furthermore,the effects of microchannel branch number on maximum thermal resistance and entransy equivalent thermal resistance of circular disc heat sink with center collection microchannels are investigated under different mass flow rates and heat fluxes.With the mass flow rate increasing,both the maximum thermal resistances and the entransy equivalent thermal resistances of heat sinks with respective fixed microchannel branch number all gradually decrease.With the heat flux increasing,the maximum thermal resistances and the entransy equivalent thermal resistances of heat sinks with respective fixed microchannel branch number remain almost unchanged.With the same mass flow rate and heat flux,the larger the microchannel branch number,the smaller the maximum thermal resistance.While the optimal microchannel branch number corresponding to minimum entransy equivalent thermal resistance is 6.展开更多
Analogizing with the definition of thermal efficiency of a heat exchanger,the entransy dissipation efficiency of a heat exchanger is defined as the ratio of dimensionless entransy dissipation rate to dimensionless pum...Analogizing with the definition of thermal efficiency of a heat exchanger,the entransy dissipation efficiency of a heat exchanger is defined as the ratio of dimensionless entransy dissipation rate to dimensionless pumping power of the heat exchanger.For the constraints of the total tube volume and total tube surface area of the heat exchanger,the constructal optimization of an H-shaped multi-scale heat exchanger is carried out by taking entransy dissipation efficiency maximization as optimization objective,and the optimal construct of the H-shaped multi-scale heat exchanger with maximum entransy dissipation efficiency is obtained.The results show that for the specified total tube volume of the heat exchanger,the optimal constructs of the first order T-shaped heat exchanger based on the maximizations of the thermal efficiency and entransy dissipation efficiency are obviously different with the lower mass flow rates of the cold and hot fluids.For the H-shaped multi-scale heat exchanger,the entransy dissipation efficiency decreases with the increase in mass flow rate when the heat exchanger order is fixed;for the specified dimensionless mass flow rate M(M<32.9),the entransy dissipation efficiency decreases with the increase in the heat exchanger order.The performance of the multi-scale heat exchanger is obviously improved compared with that of the single-scale heat exchanger.Moreover,the heat exchanger subjected to the total tube surface area constraint is also discussed in the paper.The optimization results obtained in this paper can provide a great compromise between the heat transfer and flow performances of the heat exchanger,provide some guidelines for the optimal designs of heat exchangers,and also enrich the connotation of entransy theory.展开更多
Based on thermal-entransy theory, the multi-objective constructal design of quadrilateral heat generation body(HGB) with similar shapes of leaves is studied further. The relationship between the aspect ratio of quadri...Based on thermal-entransy theory, the multi-objective constructal design of quadrilateral heat generation body(HGB) with similar shapes of leaves is studied further. The relationship between the aspect ratio of quadrilateral HGB and average temperature difference based on thermal-entransy dissipation is compared with that between the aspect ratio of quadrilateral HGB and the maximum temperature difference(MTD). The relationship between a composite function, consisting of linear weighting sum of the average temperature difference and MTD, and aspect ratio is obtained, and the optimal aspect ratios under minimum composite function with different weighting coefficients are obtained. Using the NSGA-Ⅱ algorithm, the Pareto frontier containing a series of compromise results of average temperature difference and MTD is obtained, and optimization results are compared using the deviation index. There is no aspect ratio to make both MTD and average temperature difference reach the minimum, and the optimal aspect ratio under the minimum MTD is smaller than that under the minimum average temperature difference. The optimal aspect ratio is obtained by making the composite function reach the minimum, and the optimal aspect ratios obtained by minimizing the composite function with different weighting coefficients are different. Compared with the construct of the initial design, the value of the composite function with optimal construct decreases by 1.9%, and the aspect ratio of the quadrilateral HGB decreases by 9.1%. The average temperature difference with the optimal construct increases by 2.1%, and the MTD with the optimal construct decreases by 5.6%. The deviation index under multi-objective optimization is smaller than that under single-objective optimization, and the obtained construct has better comprehensive thermal conductivity. Compared with TOPSIS and LINMAP decision-making methods, the average temperature difference with composite function optimization increases by 0.55% and 0.62% respectively, but the MTD with composite function optimization decreases by 0.84% and 0.96%.展开更多
The original interpretation of the constructive set theory CZF in Martin-Lof's type theory uses the 'extensional identity types'. It is generally believed that these 'types' do not belong to type t...The original interpretation of the constructive set theory CZF in Martin-Lof's type theory uses the 'extensional identity types'. It is generally believed that these 'types' do not belong to type theory. In this paper it will be shown that the interpretation goes through without identity types. This paper will also show that the interpretation can be given in an intensional type theory. This reflects the computational nature of the interpretation. This computational aspect is reinforced by an w-Set model of CZF展开更多
A model of non-uniform height rectangular fin, in which the variation of base's thickness and width are taken into account, is established in this paper. The dimensionless maximum thermal resistance(DMTR) and the ...A model of non-uniform height rectangular fin, in which the variation of base's thickness and width are taken into account, is established in this paper. The dimensionless maximum thermal resistance(DMTR) and the dimensionless equivalent thermal resistance(DETR) defined based on the entransy dissipation rate(EDR) are taken as performance evaluation indexes. According to constructal theory, the variations of the two indexes with the geometric parameters of the fin are analyzed by using a finite-volume computational fluid dynamics code, the effects of the fin-material fraction on the two indexes are analyzed. It is found that the two indexes decrease monotonically as the ratio between the front height and the back height of the fin increases subjected to the non-uniform height rectangular fin. When the model is reduced to the uniform height fin, the two indexes increase first and then decrease with increase in the ratio between the height of the fin and the fin space. The fin-material fraction has no effect on the change rule of the two indexes with the ratio between the height of the fin and the fin space. The sensitivity of the DETR to the geometric parameters of the fin is higher than that of the DMTR to the geometric parameters. The results obtained herein can provide some theoretical support for the thermal design of rectangular fins.展开更多
Constructal theory is introduced into the molten steel yield maximization of a converter in this paper. For the specific total cost of materials, generalized constructal optimization of a converter steel-making proces...Constructal theory is introduced into the molten steel yield maximization of a converter in this paper. For the specific total cost of materials, generalized constructal optimization of a converter steel-making process is performed. The optimal cost distribution of materials is obtained, and is also called as "generalized optimal construct". The effects of the hot metal composition contents, hot metal temperature, slag basicity and ratio of the waste steel price to the sinter ore price on the optimization results are analyzed.The results show that the molten steel yield after optimization is increased by 5.48% compared with that before optimization when sinter ore and waste steel are taken as the coolants, and the molten steel yield is increased by 6.84% when only the sinter ore is taken as the coolant. It means that taking sinter ore as coolant can improve the economic performance of the converter steelmaking process. Decreasing the contents of the silicon, phosphorus and manganese in the hot metal can increase the molten steel yield. The change of slag basicity affects the molten steel yield a little.展开更多
With the increasingly prominent phenomenon of employment difficulty,it is of great practical significance to cultivate college students’career adaptability and support their smooth transition from the campus to the w...With the increasingly prominent phenomenon of employment difficulty,it is of great practical significance to cultivate college students’career adaptability and support their smooth transition from the campus to the workplace.This study focused on college students and explored the operational mechanisms of self-leadership on career adaptability based on career construction theory,verifying the mediating effect of professional commitment and the moderating effect of social support.The research findings demonstrate that self-leadership exerts a positive impact on career adaptability.Additionally,professional commitment plays a partial mediating role between self-leadership and career adaptability,while social support functions as a moderating factor in the correlation between self-leadership and career adaptability.Notably,self-leadership exhibits a stronger positive predictive effect on the career adaptability of individuals with low social support.To enhance the career adaptability of students,it is necessary for higher education institutions(HEIs)to respect their subjectivity,emphasize self-management,and cultivate self-leadership.Furthermore,it is suggested that HEIs focus on the professional intention and learning interest of students,improving professional commitment through methods such as increasing the proportion of independent enrollment in the National College Entrance Exam(Gaokao)and expanding opportunities for changing majors during their undergraduate studies.Lastly,it is conducive to implementing categorized management and providing social support in a personalized fashion during career guidance to promote college students’career development,considering both intrinsic and extrinsic factors.展开更多
A new version of the cluster expansion is proposed without breaking the translation and rotation invariance.As an application of this technique,we construct the connected Schwinger functions of the regularized φ^(4) ...A new version of the cluster expansion is proposed without breaking the translation and rotation invariance.As an application of this technique,we construct the connected Schwinger functions of the regularized φ^(4) theory in a continuous way.展开更多
The entransy dissipation extremum principle provides new warranty and criterion for optimization of heat transfer.For a heat transfer model of a rectangular solid wall with an open T-shaped cavity,a dimensionless equi...The entransy dissipation extremum principle provides new warranty and criterion for optimization of heat transfer.For a heat transfer model of a rectangular solid wall with an open T-shaped cavity,a dimensionless equivalent thermal resistance based on entransy dissipation is taken as optimization objective,and constructal optimization for the model is carried out when the system volume,the cavity volume and the volume of rectangle occupied by T-shaped cavity are fixed.Numerical results indicate that the optimal geometry construct of cavity can be schemed out based on entransy dissipation extremum principle.The formulation of dimensionless global(maximum)thermal resistance presented in a literature is modified;some new rules which are different from those reported in the literature are obtained based on the minimization of the modified objective.Comparisons of the numerical results show that the optimal system constructs deduced respectively from the two thermal resistance objectives are very different.The optimization by taking equivalent thermal resistance minimization as objective can more effectively reduce mean temperature difference of heat transfer than the optimization by taking maximum thermal resistance minimization as objective,so that the performance of heat transfer for the total system can be improved.The more freedom the cavity has,the better the total system performance is.The correlations of the equivalent thermal resistance and the maximum thermal resistance of the system and three geometric degrees of freedom are found by using function fitting.展开更多
By taking equivalent thermal resistance,which reflects the average heat conduc-tion effect and is defined based on entransy dissipation,as optimization objective,the"volume to point"constructal problem of ho...By taking equivalent thermal resistance,which reflects the average heat conduc-tion effect and is defined based on entransy dissipation,as optimization objective,the"volume to point"constructal problem of how to discharge the heat generated in a fixed volume to a heat sink on the border through relatively high conductive link is re-analyzed and re-optimized in this paper.The constructal shape of the control volume with the best average heat conduction effect is deduced.For the elemental area and the first order construct assembly,when the thermal current density in the high conductive link is linear with the length,the optimized shapes of assemble based on the minimization of entransy dissipation are the same as those based on minimization of maximum temperature difference,and the mean tem-perature difference is 2/3 of the maximum temperature difference.For the second and higher order construct assemblies,the thermal current densities in the high conductive link are not linear with the length,and the optimized shapes of assem-ble based on the minimization of entransy dissipation are different from those based on minimization of maximum temperature difference.For the same parame-ters,the constructs based on minimization of entransy dissipation and the con-structs based on minimization of maximum temperature difference are compared,and the results show that the constructs based on entransy dissipation can de-crease the mean temperature difference better than the constructs based on mini-mization of maximum temperature difference.But with the increase of the number of the order,the mean temperature difference does not always decrease,and there exist some fluctuations.Because the idea of entransy describes the heat transfer ability more suitably,all of the heat conduction constructal problems may be re-optimized based on it.展开更多
The mass entransy and its dissipation extremum principle have opened up a new direction for the mass transfer optimization.Firstly,the emergence and development process of both the mass entransy and its dissipalion ex...The mass entransy and its dissipation extremum principle have opened up a new direction for the mass transfer optimization.Firstly,the emergence and development process of both the mass entransy and its dissipalion extremum principle are reviewed.Secondly,the combination of the mass entransy dissipation extremum principle and the finite-time thermodynamics for opti-mizing the mass transfer processes of one-way isothermal mass transfer,two-way isothermal equimolar mass transfer,and iso-thermal throttling and isothermal crystallization are summarized.Thirdly,the combination of the mass entransy dissipation ex-tremum principle and the constructal theory for optimizing the mass transfer processes of disc-to-point and volume-to-point problems are summarized.The scientific features of the mass entransy dissipation extremam principle are emphasized.展开更多
Based on constructal theory,a construct of a volume that generates heat at every point and is cooled by the coolant in the constant or tapered channel is optimized by minimizing entransy dissipation rate and flow resi...Based on constructal theory,a construct of a volume that generates heat at every point and is cooled by the coolant in the constant or tapered channel is optimized by minimizing entransy dissipation rate and flow resistance.The optimal constructs of the rectangular elements with dimensionless mean thermal resistance minimization as well as the first-,secondand thirdorder assemblies with dimensionless global flow resistance minimizations are obtained respectively.The results show that both the mean temperature difference and the limiting temperature difference of rectangular elements based on EDR(entransy dissipation rate)and MTD(maximum temperature difference)minimizations respectively are almost equal.Comparing heat transfer performances from the two optimization procedures,the dimensionless global flow resistance is decreased more for the former procedure when the assembly’s order is high.It may create great superiority for constructal optimization to combine the entransy dissipation extreme principle with heat convection.展开更多
This review paper summarizes constructal design progress performed by the authors for eight types of heat sinks with ten performance indexes being taken as the optimization objectives,respectively,by combining the met...This review paper summarizes constructal design progress performed by the authors for eight types of heat sinks with ten performance indexes being taken as the optimization objectives,respectively,by combining the methods of theoretical analysis and numerical calculation.The eight types of heat sinks are uniform height rectangular fin heat sink,non-uniform height rectangular fin heat sink,inline cylindrical pin-fin heat sink(ICPHS),plate single-row pin fin heat sink(PSRPHS),plate inline pin fin heat sink(PIPHS),plate staggered pin fin heat sink(PSPHS),single-layered microchannel heat sink(SLMCHS)with rectangular cross sections and double-layered microchannel heat sink(DLMCHS)with rectangular cross sections,respectively.And the ten performance indexes are heat transfer rate maximization,maximum thermal resistance minimization,minimization of equivalent thermal resistance which is defined based on the entransy dissipation rate(equivalent thermal resistance for short),field synergy number maximization,entropy generation rate minimization,operation cost minimization,thermo-economic function value minimization,pressure drop minimization,enhanced heat transfer factor maximization and efficiency evaluation criterion number maximization,respectively.The optimal constructs of the eight types of heat sinks with different constraints and based on the different optimization objectives are compared with each other.The results indicated that the optimal constructs mostly are different based on different optimization objectives under the same boundary condition.The optimization objective should be suitable chosen based on the focus when the constructal design for one heat sink is performed.The results obtained herein have some important theoretical significances and application values,and can provide scientific bases and theoretical guidelines for the thermal design of real heat sinks and their applications.展开更多
Using constructal entransy dissipation rate minimization method based on discrete variable cross-section conducting path,constructal optimizations of elemental area with variable cross-section conducting path are perf...Using constructal entransy dissipation rate minimization method based on discrete variable cross-section conducting path,constructal optimizations of elemental area with variable cross-section conducting path are performed,and the results are compared with the optimization results of elemental area with the constant cross-section conducting path.The comparison shows that the minimum mean temperature difference based on elemental area with variable cross-section conducting path increases and approaches a constant as the assembly's order increases,but the minimum mean temperature difference based on elemental area with constant cross-section conducting path decreases and approaches a constant as the assembly's order increases.The difference between them is caused by the different dimensionless mean temperature difference of the first order assembly.A universal constructal optimization method by self similar organization to improve heat transfer ability and its corresponding rule are proposed.With the constructal optimization method by self similar organization based on entransy dissipation rate minimization objective,the mean temperature difference approaches a constant as the assembly's order increases.展开更多
文摘We establish the construction theory of function based upon a local field Kp as underlying space. By virture of the concept of pseudo-differential operator, we introduce ＂fractal calculus＂ （or, p-type calculus, or, Gibbs-Butzer calculus）. Then, show the Jackson direct approximation theorems, Bermstein inverse approximation theorems and the equivalent approximation theorems for compact group D（C Kp） and locally compact group Kp^＋-（= Kp）, so that the foundation of construction theory of function on local fields is established. Moreover, the Jackson type, Bernstein type, and equivalent approximation theorems on the HOlder-type space C^σ（Kp）, σ 〉0, are proved; then the equivalent approximation theorem on Sobolev-type space Wr（Kp）, σ≥0, 1≤r 〈∞, is shown.
文摘The generative operations concerning the transformation between the active and the passive convert successively from PS rules, T-rules, D-structure, NP preposing and postposing, X-bar analysis, to case theory, government, checking theory and head movement. The development of the passive construct mirrors the trend of the progress of Chomskyan theory, evolving from the rule motivations to the principle motivations. The giant leap between the phases of the generative grammar has aroused great curiosity among the scholars and learners of syntax. In this paper, the author will explore the tacit strategy underlying the module changes of TG from the perspective of cognitive science.
基金financial provided by the National Natural Science Foundation of China (Nos. 50474066, 50874108, 51274201, and 51674260)the Coal Joint Fund from National Natural Science Foundation of China and Shenhua Group Corporation Limited (No. U1361116)the National Basic Research Program of China (No. 2012CB214900)
文摘Although human beings have come to understand and utilize coal for a very long history, no theoretical breakthrough in the study of coal structure has been made, which still needs continuous efforts of coal chemical workers. Based on the viewpoint of ‘vague/clear', the species classification and accurate analysis on coal were conducted by using the natural clustering all-component separation method. A more systematic and detailed coal embedded structure model theory which is suitable for coal of all ranks was developed from the previous one and a more complete theoretical system about the component and structure of coal was constructed. The whole establishment process of the theory was summarized and some of the main support data and analysis test results, including TEM, AFM, FTIR, GC/MS, MALDI/TOF/MS, DART/MSD, fractal analysis and so on were provided. The coal embedded structure theory fully considers both the identity and the particularity of all-rank coal, reflects the coal component and structure in the full range of coal rank, solves the systematic cognitive problem of coal component and structure on macro and micro level, and provides a valuable and meaningful theoretical approach for the coal processing and conversion technology.
文摘Construction grammar attempts to reveal the nature, structure, and functions of language. As a theoretical system of language based on cognitive linguistics, construction grammar is a reaction and thus a contrast to the traditional generative grammar. This paper tries to outline the major propositions of construction grammar and construction theory, analyses the significance of constructions and their relations to second language acquisition （SLA） and the routes of construction acquisition in SLA, plus the orientations in research on the relations between construction acquisition and SLA.
基金the 2013 major project of the Key Research Bases of Humanities and Social Sciences of the Ministry of Education of the People’s Republic of China“Research on the Establishment and Application of the Knowledge Database of Modern Chinese Construction Grammar”(13JJD740001)the 2015 major project of the Key Research Bases of Humanities and Social Sciences of the Ministry of Education of the People’s Republic of China“Semantic analysis of Construction Grammar and Its Annotation in the Corpus”(15JJD740002).
文摘“Form-meaning pair”is not a distinctive feature of constructions,but a universal feature of all things.A construction must be a structure.Morphemes are the smallest sound-meaning assemblies,but they only represent a symbolic relationship which has no internal structure;thus,they are not constructions.In addition,if morphemes are also treated as constructions,there is a problem of“heterogeneity”in understanding the“form”of constructions.As to the rising“constructionist”and the traditional“atomist”dichotomy,we feel the“constructionist”approach complies better with the actual linguistic life.Construction Grammar leads people to pay close attention to the integrity of constructions and the cognitive mechanisms behind linguistic facts.Therefore,it is of great value both theoretically and practically.However,since Construction Grammar has not yet displayed a distinct value in terms of methodology,we must be careful not to overrate it or overestimate it.
基金supported by the National Natural Science Foundation of China(Grant No.51176203)the Natural Science Foundation of Naval University of Engineering(Grant No.HGDYDJJ10011)
文摘The emergence and development of constructal theory,which has been a new discipline branch to research sorts of structures in nature and engineering,are reviewed.The core of the constructal theory is that various shapes and structures of the matters in nature are generated from the tendency to obtain optimal performance.Constructal theory and its application are summarized,from disciplines such as heat,mechanism,fluid flow,electricity,magnetism and chemistry,to life and non-life systems in nature.
基金supported by the National Natural Science Foundation of China(Grant Nos.51979278,51579244 and 51506220)。
文摘Thermal designs for microchannel heat sinks with laminar flow are conducted numerically by combining constructal theory and entransy theory.Three types of 3-D circular disc heat sink models,i.e.without collection microchannels,with center collection microchannels,and with edge collection microchannels,are established respectively.Compared with the entransy equivalent thermal resistances of circular disc heat sink without collection microchannels and circular disc heat sink with edge collection microchannels,that of circular disc heat sink with center collection microchannels is the minimum,so the overall heat transfer performance of circular disc heat sink with center collection microchannels has obvious advantages.Furthermore,the effects of microchannel branch number on maximum thermal resistance and entransy equivalent thermal resistance of circular disc heat sink with center collection microchannels are investigated under different mass flow rates and heat fluxes.With the mass flow rate increasing,both the maximum thermal resistances and the entransy equivalent thermal resistances of heat sinks with respective fixed microchannel branch number all gradually decrease.With the heat flux increasing,the maximum thermal resistances and the entransy equivalent thermal resistances of heat sinks with respective fixed microchannel branch number remain almost unchanged.With the same mass flow rate and heat flux,the larger the microchannel branch number,the smaller the maximum thermal resistance.While the optimal microchannel branch number corresponding to minimum entransy equivalent thermal resistance is 6.
基金supported by the National Natural Science Foundation of China (Grant No. 51176203)the Natural Science Foundation for Youngsters of Naval University of Engineering (Grant No. HGDQNJJ11008)
文摘Analogizing with the definition of thermal efficiency of a heat exchanger,the entransy dissipation efficiency of a heat exchanger is defined as the ratio of dimensionless entransy dissipation rate to dimensionless pumping power of the heat exchanger.For the constraints of the total tube volume and total tube surface area of the heat exchanger,the constructal optimization of an H-shaped multi-scale heat exchanger is carried out by taking entransy dissipation efficiency maximization as optimization objective,and the optimal construct of the H-shaped multi-scale heat exchanger with maximum entransy dissipation efficiency is obtained.The results show that for the specified total tube volume of the heat exchanger,the optimal constructs of the first order T-shaped heat exchanger based on the maximizations of the thermal efficiency and entransy dissipation efficiency are obviously different with the lower mass flow rates of the cold and hot fluids.For the H-shaped multi-scale heat exchanger,the entransy dissipation efficiency decreases with the increase in mass flow rate when the heat exchanger order is fixed;for the specified dimensionless mass flow rate M(M<32.9),the entransy dissipation efficiency decreases with the increase in the heat exchanger order.The performance of the multi-scale heat exchanger is obviously improved compared with that of the single-scale heat exchanger.Moreover,the heat exchanger subjected to the total tube surface area constraint is also discussed in the paper.The optimization results obtained in this paper can provide a great compromise between the heat transfer and flow performances of the heat exchanger,provide some guidelines for the optimal designs of heat exchangers,and also enrich the connotation of entransy theory.
基金supported by the National Natural Science Foundation of China(Grant No.52171317)。
文摘Based on thermal-entransy theory, the multi-objective constructal design of quadrilateral heat generation body(HGB) with similar shapes of leaves is studied further. The relationship between the aspect ratio of quadrilateral HGB and average temperature difference based on thermal-entransy dissipation is compared with that between the aspect ratio of quadrilateral HGB and the maximum temperature difference(MTD). The relationship between a composite function, consisting of linear weighting sum of the average temperature difference and MTD, and aspect ratio is obtained, and the optimal aspect ratios under minimum composite function with different weighting coefficients are obtained. Using the NSGA-Ⅱ algorithm, the Pareto frontier containing a series of compromise results of average temperature difference and MTD is obtained, and optimization results are compared using the deviation index. There is no aspect ratio to make both MTD and average temperature difference reach the minimum, and the optimal aspect ratio under the minimum MTD is smaller than that under the minimum average temperature difference. The optimal aspect ratio is obtained by making the composite function reach the minimum, and the optimal aspect ratios obtained by minimizing the composite function with different weighting coefficients are different. Compared with the construct of the initial design, the value of the composite function with optimal construct decreases by 1.9%, and the aspect ratio of the quadrilateral HGB decreases by 9.1%. The average temperature difference with the optimal construct increases by 2.1%, and the MTD with the optimal construct decreases by 5.6%. The deviation index under multi-objective optimization is smaller than that under single-objective optimization, and the obtained construct has better comprehensive thermal conductivity. Compared with TOPSIS and LINMAP decision-making methods, the average temperature difference with composite function optimization increases by 0.55% and 0.62% respectively, but the MTD with composite function optimization decreases by 0.84% and 0.96%.
文摘The original interpretation of the constructive set theory CZF in Martin-Lof's type theory uses the 'extensional identity types'. It is generally believed that these 'types' do not belong to type theory. In this paper it will be shown that the interpretation goes through without identity types. This paper will also show that the interpretation can be given in an intensional type theory. This reflects the computational nature of the interpretation. This computational aspect is reinforced by an w-Set model of CZF
基金supported by the National Natural Science Foundation of China (Grant Nos. 51579244, 51506220 and 51356001)
文摘A model of non-uniform height rectangular fin, in which the variation of base's thickness and width are taken into account, is established in this paper. The dimensionless maximum thermal resistance(DMTR) and the dimensionless equivalent thermal resistance(DETR) defined based on the entransy dissipation rate(EDR) are taken as performance evaluation indexes. According to constructal theory, the variations of the two indexes with the geometric parameters of the fin are analyzed by using a finite-volume computational fluid dynamics code, the effects of the fin-material fraction on the two indexes are analyzed. It is found that the two indexes decrease monotonically as the ratio between the front height and the back height of the fin increases subjected to the non-uniform height rectangular fin. When the model is reduced to the uniform height fin, the two indexes increase first and then decrease with increase in the ratio between the height of the fin and the fin space. The fin-material fraction has no effect on the change rule of the two indexes with the ratio between the height of the fin and the fin space. The sensitivity of the DETR to the geometric parameters of the fin is higher than that of the DMTR to the geometric parameters. The results obtained herein can provide some theoretical support for the thermal design of rectangular fins.
基金supported by the National Natural Science Foundation of China(Grant Nos.51506220&51579244)the National Key Basic Research and Development Program of China(Grant No.2012CB720405)
文摘Constructal theory is introduced into the molten steel yield maximization of a converter in this paper. For the specific total cost of materials, generalized constructal optimization of a converter steel-making process is performed. The optimal cost distribution of materials is obtained, and is also called as "generalized optimal construct". The effects of the hot metal composition contents, hot metal temperature, slag basicity and ratio of the waste steel price to the sinter ore price on the optimization results are analyzed.The results show that the molten steel yield after optimization is increased by 5.48% compared with that before optimization when sinter ore and waste steel are taken as the coolants, and the molten steel yield is increased by 6.84% when only the sinter ore is taken as the coolant. It means that taking sinter ore as coolant can improve the economic performance of the converter steelmaking process. Decreasing the contents of the silicon, phosphorus and manganese in the hot metal can increase the molten steel yield. The change of slag basicity affects the molten steel yield a little.
基金funded by the Youth Program of the National Natural Science Foundation of China,“Study on the Process and Mechanism of Career Decision-Making Based on Dual Process Theory”(No.72201036).
文摘With the increasingly prominent phenomenon of employment difficulty,it is of great practical significance to cultivate college students’career adaptability and support their smooth transition from the campus to the workplace.This study focused on college students and explored the operational mechanisms of self-leadership on career adaptability based on career construction theory,verifying the mediating effect of professional commitment and the moderating effect of social support.The research findings demonstrate that self-leadership exerts a positive impact on career adaptability.Additionally,professional commitment plays a partial mediating role between self-leadership and career adaptability,while social support functions as a moderating factor in the correlation between self-leadership and career adaptability.Notably,self-leadership exhibits a stronger positive predictive effect on the career adaptability of individuals with low social support.To enhance the career adaptability of students,it is necessary for higher education institutions(HEIs)to respect their subjectivity,emphasize self-management,and cultivate self-leadership.Furthermore,it is suggested that HEIs focus on the professional intention and learning interest of students,improving professional commitment through methods such as increasing the proportion of independent enrollment in the National College Entrance Exam(Gaokao)and expanding opportunities for changing majors during their undergraduate studies.Lastly,it is conducive to implementing categorized management and providing social support in a personalized fashion during career guidance to promote college students’career development,considering both intrinsic and extrinsic factors.
文摘A new version of the cluster expansion is proposed without breaking the translation and rotation invariance.As an application of this technique,we construct the connected Schwinger functions of the regularized φ^(4) theory in a continuous way.
基金Supported by the Program for New Century Excellent Talents in Universities of China(Grant No.20041006)Foundation for the Authors of National Excellent Doctoral Dissertation of China(Grant No.200136)
文摘The entransy dissipation extremum principle provides new warranty and criterion for optimization of heat transfer.For a heat transfer model of a rectangular solid wall with an open T-shaped cavity,a dimensionless equivalent thermal resistance based on entransy dissipation is taken as optimization objective,and constructal optimization for the model is carried out when the system volume,the cavity volume and the volume of rectangle occupied by T-shaped cavity are fixed.Numerical results indicate that the optimal geometry construct of cavity can be schemed out based on entransy dissipation extremum principle.The formulation of dimensionless global(maximum)thermal resistance presented in a literature is modified;some new rules which are different from those reported in the literature are obtained based on the minimization of the modified objective.Comparisons of the numerical results show that the optimal system constructs deduced respectively from the two thermal resistance objectives are very different.The optimization by taking equivalent thermal resistance minimization as objective can more effectively reduce mean temperature difference of heat transfer than the optimization by taking maximum thermal resistance minimization as objective,so that the performance of heat transfer for the total system can be improved.The more freedom the cavity has,the better the total system performance is.The correlations of the equivalent thermal resistance and the maximum thermal resistance of the system and three geometric degrees of freedom are found by using function fitting.
基金Supported by the Program for New Century Excellent Talents in University of Chinathe Foundation for the Author of National Excellent Doctoral Dissertation of China(Grant No.200136)
文摘By taking equivalent thermal resistance,which reflects the average heat conduc-tion effect and is defined based on entransy dissipation,as optimization objective,the"volume to point"constructal problem of how to discharge the heat generated in a fixed volume to a heat sink on the border through relatively high conductive link is re-analyzed and re-optimized in this paper.The constructal shape of the control volume with the best average heat conduction effect is deduced.For the elemental area and the first order construct assembly,when the thermal current density in the high conductive link is linear with the length,the optimized shapes of assemble based on the minimization of entransy dissipation are the same as those based on minimization of maximum temperature difference,and the mean tem-perature difference is 2/3 of the maximum temperature difference.For the second and higher order construct assemblies,the thermal current densities in the high conductive link are not linear with the length,and the optimized shapes of assem-ble based on the minimization of entransy dissipation are different from those based on minimization of maximum temperature difference.For the same parame-ters,the constructs based on minimization of entransy dissipation and the con-structs based on minimization of maximum temperature difference are compared,and the results show that the constructs based on entransy dissipation can de-crease the mean temperature difference better than the constructs based on mini-mization of maximum temperature difference.But with the increase of the number of the order,the mean temperature difference does not always decrease,and there exist some fluctuations.Because the idea of entransy describes the heat transfer ability more suitably,all of the heat conduction constructal problems may be re-optimized based on it.
基金supported by the National Natural Science Foundation China(Grant Nos.51176203 and 10905093)
文摘The mass entransy and its dissipation extremum principle have opened up a new direction for the mass transfer optimization.Firstly,the emergence and development process of both the mass entransy and its dissipalion extremum principle are reviewed.Secondly,the combination of the mass entransy dissipation extremum principle and the finite-time thermodynamics for opti-mizing the mass transfer processes of one-way isothermal mass transfer,two-way isothermal equimolar mass transfer,and iso-thermal throttling and isothermal crystallization are summarized.Thirdly,the combination of the mass entransy dissipation ex-tremum principle and the constructal theory for optimizing the mass transfer processes of disc-to-point and volume-to-point problems are summarized.The scientific features of the mass entransy dissipation extremam principle are emphasized.
基金supported by the National Natural Science Foundation of China(Grant No.10905093)the Program for New Century Excellent Talents in University of China(Grant No.NCET-04-1006)the Foundation for the Author of National Excellent Doctoral Dissertation of China(Grant No.200136)
文摘Based on constructal theory,a construct of a volume that generates heat at every point and is cooled by the coolant in the constant or tapered channel is optimized by minimizing entransy dissipation rate and flow resistance.The optimal constructs of the rectangular elements with dimensionless mean thermal resistance minimization as well as the first-,secondand thirdorder assemblies with dimensionless global flow resistance minimizations are obtained respectively.The results show that both the mean temperature difference and the limiting temperature difference of rectangular elements based on EDR(entransy dissipation rate)and MTD(maximum temperature difference)minimizations respectively are almost equal.Comparing heat transfer performances from the two optimization procedures,the dimensionless global flow resistance is decreased more for the former procedure when the assembly’s order is high.It may create great superiority for constructal optimization to combine the entransy dissipation extreme principle with heat convection.
基金supported by the National Natural Science Foundation of China(Grant Nos.51779262,51506220 and 51579244)。
文摘This review paper summarizes constructal design progress performed by the authors for eight types of heat sinks with ten performance indexes being taken as the optimization objectives,respectively,by combining the methods of theoretical analysis and numerical calculation.The eight types of heat sinks are uniform height rectangular fin heat sink,non-uniform height rectangular fin heat sink,inline cylindrical pin-fin heat sink(ICPHS),plate single-row pin fin heat sink(PSRPHS),plate inline pin fin heat sink(PIPHS),plate staggered pin fin heat sink(PSPHS),single-layered microchannel heat sink(SLMCHS)with rectangular cross sections and double-layered microchannel heat sink(DLMCHS)with rectangular cross sections,respectively.And the ten performance indexes are heat transfer rate maximization,maximum thermal resistance minimization,minimization of equivalent thermal resistance which is defined based on the entransy dissipation rate(equivalent thermal resistance for short),field synergy number maximization,entropy generation rate minimization,operation cost minimization,thermo-economic function value minimization,pressure drop minimization,enhanced heat transfer factor maximization and efficiency evaluation criterion number maximization,respectively.The optimal constructs of the eight types of heat sinks with different constraints and based on the different optimization objectives are compared with each other.The results indicated that the optimal constructs mostly are different based on different optimization objectives under the same boundary condition.The optimization objective should be suitable chosen based on the focus when the constructal design for one heat sink is performed.The results obtained herein have some important theoretical significances and application values,and can provide scientific bases and theoretical guidelines for the thermal design of real heat sinks and their applications.
基金supported by Program for New Century Excellent Talents in Universities of China and the Foundation for the Author of National Excellent Doctoral Dissertation of China(Grant No.200136)
文摘Using constructal entransy dissipation rate minimization method based on discrete variable cross-section conducting path,constructal optimizations of elemental area with variable cross-section conducting path are performed,and the results are compared with the optimization results of elemental area with the constant cross-section conducting path.The comparison shows that the minimum mean temperature difference based on elemental area with variable cross-section conducting path increases and approaches a constant as the assembly's order increases,but the minimum mean temperature difference based on elemental area with constant cross-section conducting path decreases and approaches a constant as the assembly's order increases.The difference between them is caused by the different dimensionless mean temperature difference of the first order assembly.A universal constructal optimization method by self similar organization to improve heat transfer ability and its corresponding rule are proposed.With the constructal optimization method by self similar organization based on entransy dissipation rate minimization objective,the mean temperature difference approaches a constant as the assembly's order increases.
