This paper studies a Sparre Andersen negative risk sums model in which the distribution of "interclaim" time is that of a sum of n independent exponential random variables. Thus, the Erlang(n) model is a special c...This paper studies a Sparre Andersen negative risk sums model in which the distribution of "interclaim" time is that of a sum of n independent exponential random variables. Thus, the Erlang(n) model is a special case. On this basis the correlated negative risk sums process with the common Erlang process is considered. Integro-differential equations with boundary conditions for ψ(u) are given. For some special cases a closed-form expression for ψ(u) is derived.展开更多
We compare the results of some perturbative quantum dissipation approaches to the exact linear absorption of two state systems. The considered approximate methods are the so-called complete second-order quantum dissip...We compare the results of some perturbative quantum dissipation approaches to the exact linear absorption of two state systems. The considered approximate methods are the so-called complete second-order quantum dissipation theories, in either the chronological ordering prescription or the correlated driving-dissipation form. Analytical results can be derived for the linear absorption of two-state systems. Assessments on their applicability are then made by comparison to the exact results.展开更多
The average-passage equation system (APES) provides a rigorous mathematical framework for account- ing for the unsteady blade row interaction through multi- stage compressors in steady state environment by introduc-...The average-passage equation system (APES) provides a rigorous mathematical framework for account- ing for the unsteady blade row interaction through multi- stage compressors in steady state environment by introduc- ing deterministic correlations (DC) that need to be modeled to close the equation system. The primary purpose of this study is to provide insight into the DC characteristics and the influence of DC on the time-averaged flow field of the APES. In Part 1 of this two-part paper, firstly a 3D viscous unsteady and time-averaging flow CFD solver is developed to investi- gate the APES technique. Then steady and unsteady simu- lations are conducted in a transonic compressor stage. The results from both simulations are compared to highlight the significance of the unsteady interactions. Furthermore, the distribution characteristics of DC are studied and the DC at the rotor/stator interface are compared with their spatial cor- relations (SC). Lastly, steady and time-averaging (employing APES with DC) simulations for the downstream stator alone are conducted employing DC derived from the unsteady re- suits. The results from steady and time-averaging simula- tions are compared with the time-averaged unsteady results. The comparisons demonstrate that the simulation employing APES with DC can reproduce the time-averaged field and the 3D viscous time-averaging flow solver is validated.展开更多
Vector transducer can simultaneously measure components of particle velocity as well as pressure at some point in sound field. In this paper, a series of equations are obtained from the correlation of particle velocit...Vector transducer can simultaneously measure components of particle velocity as well as pressure at some point in sound field. In this paper, a series of equations are obtained from the correlation of particle velocity and pressure of the incident wave field, the error of each equation with white noise is studied, and Differential Evolution is used in solving the equations to distinguish multi-sources. Results of computer simulation show that Differential Evolution has more superiority than Genetic Algorithms on the rate and precision of convergence under the same condition.展开更多
The research work was carried out to compare and evaluate the extractability of cationic micronutrients(Zn,Cu,Fe and Mn)using widely employed diethylene triamine pentaacetic acid(DTPA)-triethanolamine(TEA)-CaCl2 metho...The research work was carried out to compare and evaluate the extractability of cationic micronutrients(Zn,Cu,Fe and Mn)using widely employed diethylene triamine pentaacetic acid(DTPA)-triethanolamine(TEA)-CaCl2 method with that of multinutrient extractant(ammonium bicarbonate(AB)-DTPA)in Inceptisols,Alfisols and Entisols in the erstwhile united Andhra Pradesh.The percent variation of extraction of Zn was higher in soils with DTPA-TEA-CaCl2 over AB-DTPA method in all the soil orders(types)in the range of 35.3% to 46.2%.AB-DTPA extracted high amounts of Cu to an extent of 10%-21% in Entisols and Alfisls,respectively.In Inceptisols both extracatants extracted equal amounts of Cu.AB-DTPA extracted high amounts of Fe 13% and 18% in Alfisols and Entisols compared to that of DTPA-TEA-CaCl2 method and DTPA-TEA-CaCl2 method was good extract for Fe in Inceptisols and even for Mn in Alfisols.The amounts of micronutrient contents extracted were found to be highly and significantly correlated with soil properties like electrical conductivity(EC)and organic carbon(OC).The individual micronutrient contents of Zn,Cu and Fe extracted by DTPA-TEA-CaCl2 methods were found to be highly correlated with that of AB-DTPA extractant.However,such correlation was not observed for Mn extraction when all soils were grouped.展开更多
This work consists of estimating the energy achieved from all land and water-based vegetations. This real potential is determined by identifying 10 biomass samples taken from vegetable resources which are favored by t...This work consists of estimating the energy achieved from all land and water-based vegetations. This real potential is determined by identifying 10 biomass samples taken from vegetable resources which are favored by their aptitude of adaptation to the conditions of Iran. The net energy values of the 10 biomass samples change in the range of 13.65-18.00 MJ/kg using bomb calorimeter. By means of least squarere regression method all correlations were found. The results of 10 different biomass materials have been used to develop a linear equation correlation.展开更多
The sustainable synthesis of dimethyl maleate via diesterification through the utilization of ionic liquid(IL)is of great importance.However,the relationship between the ILs nature and the reactivity of diesterificati...The sustainable synthesis of dimethyl maleate via diesterification through the utilization of ionic liquid(IL)is of great importance.However,the relationship between the ILs nature and the reactivity of diesterification is still unclear.Herein,a series of ILs with different structures were selected for the comprehensive investigation of diesterification.The acidity(H_(0))and Kamlet-Taft solvent parameters(hydrogen bond donor ability(α),hydrogen bond acceptor ability(β),and polarizability(π^(*)))of ILs were measured by UV–Visible spectroscopy,and the effects of them on the diesterification of maleic anhydride were also studied in detail.The results indicated that not only H0of the IL-based catalysis system,but also itsα,β,andπ^(*)influenced the reaction activity of diesterification.Furthermore,a quantifiable correlation was fitted between the natural logarithm of the rate constant and multiple parameters of ILs,indicating that the diesterification rate had a positive correlation with the H0,α,andπ^(*),and inverse correlation with theβof the IL.A plausible synergetic reaction mechanism for the excellent performance of[(HSO_(3))PMim][HSO_(4)]has been proposed.Overall,this work thoroughly explored the relationship between the nature of ILs on diesterification in-depth,which will reveal the nature of diesterification in detail.展开更多
While modem prestressed techniques have improved the torsion properties of high-strength concrete (HSC) composite beams with prestressed steel (PS) boxes, no research has been reported in either the national or in...While modem prestressed techniques have improved the torsion properties of high-strength concrete (HSC) composite beams with prestressed steel (PS) boxes, no research has been reported in either the national or international literature on the an- ti-torque and composite torque properties of this type of beam. With the aim of understanding the torque properties of these beams, this paper presents results of ten comprehensive tests; three of these were based on stirrup spacings and prestressing levels as the main parameters, while the other seven were based on torsional rates. The torsion tests were conducted on the re- sults which established several key parameters, including curves of constant torsion, strain curves of steel torsion, strain distri- bution of steel beams and concrete, curves of bending-moment and mid-span deflection, as well as cross strain distribution.The prestressing impact-factor method was adopted to deduce semiempirical equations for cracking torque in such composite beams. Furthermore, this involves the use of the equation of ultimate torque based on tress-model-theory of the distortion an- gle, the calculated results show good agreement with the measured values. In summary, this paper offers theoretical analysis for future applications of HSC composite beams with PS boxes, and provides both validation of the methods employed and a reference point for on-going research on composite beams and related anti-torque studies.展开更多
基金Supported by the Foundation of Suzhou Science and Technology University
文摘This paper studies a Sparre Andersen negative risk sums model in which the distribution of "interclaim" time is that of a sum of n independent exponential random variables. Thus, the Erlang(n) model is a special case. On this basis the correlated negative risk sums process with the common Erlang process is considered. Integro-differential equations with boundary conditions for ψ(u) are given. For some special cases a closed-form expression for ψ(u) is derived.
文摘We compare the results of some perturbative quantum dissipation approaches to the exact linear absorption of two state systems. The considered approximate methods are the so-called complete second-order quantum dissipation theories, in either the chronological ordering prescription or the correlated driving-dissipation form. Analytical results can be derived for the linear absorption of two-state systems. Assessments on their applicability are then made by comparison to the exact results.
基金supported by the National Natural Science Foundation of China (51006006,51136003,50976010,50976009)the National Basic Research Program of China (2012CB720205)+2 种基金the Aeronautical Science Foundation of China (2010ZB51)the 111 Project (B08009)the National Science Special Foundation for Post-doctoral Scientists of China (201104049)
文摘The average-passage equation system (APES) provides a rigorous mathematical framework for account- ing for the unsteady blade row interaction through multi- stage compressors in steady state environment by introduc- ing deterministic correlations (DC) that need to be modeled to close the equation system. The primary purpose of this study is to provide insight into the DC characteristics and the influence of DC on the time-averaged flow field of the APES. In Part 1 of this two-part paper, firstly a 3D viscous unsteady and time-averaging flow CFD solver is developed to investi- gate the APES technique. Then steady and unsteady simu- lations are conducted in a transonic compressor stage. The results from both simulations are compared to highlight the significance of the unsteady interactions. Furthermore, the distribution characteristics of DC are studied and the DC at the rotor/stator interface are compared with their spatial cor- relations (SC). Lastly, steady and time-averaging (employing APES with DC) simulations for the downstream stator alone are conducted employing DC derived from the unsteady re- suits. The results from steady and time-averaging simula- tions are compared with the time-averaged unsteady results. The comparisons demonstrate that the simulation employing APES with DC can reproduce the time-averaged field and the 3D viscous time-averaging flow solver is validated.
文摘Vector transducer can simultaneously measure components of particle velocity as well as pressure at some point in sound field. In this paper, a series of equations are obtained from the correlation of particle velocity and pressure of the incident wave field, the error of each equation with white noise is studied, and Differential Evolution is used in solving the equations to distinguish multi-sources. Results of computer simulation show that Differential Evolution has more superiority than Genetic Algorithms on the rate and precision of convergence under the same condition.
文摘The research work was carried out to compare and evaluate the extractability of cationic micronutrients(Zn,Cu,Fe and Mn)using widely employed diethylene triamine pentaacetic acid(DTPA)-triethanolamine(TEA)-CaCl2 method with that of multinutrient extractant(ammonium bicarbonate(AB)-DTPA)in Inceptisols,Alfisols and Entisols in the erstwhile united Andhra Pradesh.The percent variation of extraction of Zn was higher in soils with DTPA-TEA-CaCl2 over AB-DTPA method in all the soil orders(types)in the range of 35.3% to 46.2%.AB-DTPA extracted high amounts of Cu to an extent of 10%-21% in Entisols and Alfisls,respectively.In Inceptisols both extracatants extracted equal amounts of Cu.AB-DTPA extracted high amounts of Fe 13% and 18% in Alfisols and Entisols compared to that of DTPA-TEA-CaCl2 method and DTPA-TEA-CaCl2 method was good extract for Fe in Inceptisols and even for Mn in Alfisols.The amounts of micronutrient contents extracted were found to be highly and significantly correlated with soil properties like electrical conductivity(EC)and organic carbon(OC).The individual micronutrient contents of Zn,Cu and Fe extracted by DTPA-TEA-CaCl2 methods were found to be highly correlated with that of AB-DTPA extractant.However,such correlation was not observed for Mn extraction when all soils were grouped.
文摘This work consists of estimating the energy achieved from all land and water-based vegetations. This real potential is determined by identifying 10 biomass samples taken from vegetable resources which are favored by their aptitude of adaptation to the conditions of Iran. The net energy values of the 10 biomass samples change in the range of 13.65-18.00 MJ/kg using bomb calorimeter. By means of least squarere regression method all correlations were found. The results of 10 different biomass materials have been used to develop a linear equation correlation.
基金supported by the National Natural Science Foundation of China(21878315)the National Key Research and Development Program of China(2017YFA0206803)+1 种基金the Key Programs of the Chinese Academy of Sciences(KFZD-SW-413)the Key Programs of Innovation Academy for Green Manufacture,CAS(IAGM2020C17)。
文摘The sustainable synthesis of dimethyl maleate via diesterification through the utilization of ionic liquid(IL)is of great importance.However,the relationship between the ILs nature and the reactivity of diesterification is still unclear.Herein,a series of ILs with different structures were selected for the comprehensive investigation of diesterification.The acidity(H_(0))and Kamlet-Taft solvent parameters(hydrogen bond donor ability(α),hydrogen bond acceptor ability(β),and polarizability(π^(*)))of ILs were measured by UV–Visible spectroscopy,and the effects of them on the diesterification of maleic anhydride were also studied in detail.The results indicated that not only H0of the IL-based catalysis system,but also itsα,β,andπ^(*)influenced the reaction activity of diesterification.Furthermore,a quantifiable correlation was fitted between the natural logarithm of the rate constant and multiple parameters of ILs,indicating that the diesterification rate had a positive correlation with the H0,α,andπ^(*),and inverse correlation with theβof the IL.A plausible synergetic reaction mechanism for the excellent performance of[(HSO_(3))PMim][HSO_(4)]has been proposed.Overall,this work thoroughly explored the relationship between the nature of ILs on diesterification in-depth,which will reveal the nature of diesterification in detail.
基金supported by the National Natural Science Foundation of China (Grant No. 50879048)"948" Project of the Ministry of Water Resources of China (Grant No. 201127)
文摘While modem prestressed techniques have improved the torsion properties of high-strength concrete (HSC) composite beams with prestressed steel (PS) boxes, no research has been reported in either the national or international literature on the an- ti-torque and composite torque properties of this type of beam. With the aim of understanding the torque properties of these beams, this paper presents results of ten comprehensive tests; three of these were based on stirrup spacings and prestressing levels as the main parameters, while the other seven were based on torsional rates. The torsion tests were conducted on the re- sults which established several key parameters, including curves of constant torsion, strain curves of steel torsion, strain distri- bution of steel beams and concrete, curves of bending-moment and mid-span deflection, as well as cross strain distribution.The prestressing impact-factor method was adopted to deduce semiempirical equations for cracking torque in such composite beams. Furthermore, this involves the use of the equation of ultimate torque based on tress-model-theory of the distortion an- gle, the calculated results show good agreement with the measured values. In summary, this paper offers theoretical analysis for future applications of HSC composite beams with PS boxes, and provides both validation of the methods employed and a reference point for on-going research on composite beams and related anti-torque studies.