A computer software to simulate the phase transformation during quenching is designed based on Avrami equation and Scheil additivity principle of incubation period. The isothermal transformation diagrams of supercool...A computer software to simulate the phase transformation during quenching is designed based on Avrami equation and Scheil additivity principle of incubation period. The isothermal transformation diagrams of supercooled austenite are described by cubic spline functions. This software is possess of a good graphic interface of Windows style, can simulate the whole process in austenite decomposition during continuous cooling. If the cooling rate was given, the fraction of various microstructures transformed of austenite decomposition during continuous cooling at any temperature can be calculated. The simulation results are checked with the quenching experiment of 45 steel. The results indicate that the simulation results are comparatively close to the experimental results.展开更多
Nd-rich phase plays an important role in the magnetic properties of sintered NdFeB alloy. The proportion of Nd-rich phase to all the other phases was calculated by using MATLAB 6.5 software. Especially, post-sintered ...Nd-rich phase plays an important role in the magnetic properties of sintered NdFeB alloy. The proportion of Nd-rich phase to all the other phases was calculated by using MATLAB 6.5 software. Especially, post-sintered alloy, post-high-temperature tempered alloy and post-high and low-temperature tempered alloy were analyzed. It was found that the proportion of Nd-rich phase in the three alloys based on SEM (scanning electron microscope) images was about 8.22%, 8.03% and 8.00%, respectively.展开更多
This paper presents the design of a computational software system that enables solutions of multi-phase and multi-scale problems in mechanics. It demonstrated how mechanicians can design “process-driven” software sy...This paper presents the design of a computational software system that enables solutions of multi-phase and multi-scale problems in mechanics. It demonstrated how mechanicians can design “process-driven” software systems directly, and that such efforts are more suitable in solving multi-phase or multi-scale problems, rather than utilizing the “data-driven” approaches of legacy network systems. Specifically, this paper demonstrates how this approach can be used to solve problems in flexible dynamics. Then it suggests a view of mechanics algorithms as ‘state equilibrium’ enforcers residing as servers, rather than as computer programs that solve field equations. It puts forth the need for identical input/output files to ensure widespread deployment on laptops. Then it presents an assessment of the laptop platform. A software system such as the one presented here can also be used to supply virtual environments, animations and entertainment/education software with physics.展开更多
Software reliability modeling and prediction are important issues during software development, especially when one has to reach a desired reliability prior to software release. Various techniques, both static and dyna...Software reliability modeling and prediction are important issues during software development, especially when one has to reach a desired reliability prior to software release. Various techniques, both static and dynamic, are used for reliability modeling and prediction in the context of software risk management. The single-phase Rayleigh model is a dynamic reliability model;however, it is not suitable for software release date prediction. We propose a new multi-phase truncated Rayleigh model and obtain parameter estimation using the nonlinear least squares method. The proposed model has been successfully tested in a large software company for several software projects. It is shown that the two-phase truncated Rayleigh model outperforms the traditional single-phase Rayleigh model in modeling weekly software defect arrival data. The model is useful for project management in planning release times and defect management.展开更多
Suppressing jitter noises in a phase locked loop（ PLL） is of great importance in order to keep precise and continuous track of global positioning system （GPS）signals characterized by low carrier-to-noise ratio（ C...Suppressing jitter noises in a phase locked loop（ PLL） is of great importance in order to keep precise and continuous track of global positioning system （GPS）signals characterized by low carrier-to-noise ratio（ C/No ）. This article proposes and analyzes an improved Kalman-filter-based PLL to process weak carrier signals in GPS software receivers. After reviewing the optimal-bandwidth-based traditional second-order PLL, a Kalman-filter-based estimation algorithm is implemented for the new PLL by decorrelating the model error noises and the measurement noises. Finally,the efficiency of this new Kalman-filter-based PLL is verified by experimental data. Compared to the traditional second-order PLL, this new PLL is in position to make correct estimation of the carrier phase differences and Doppler shifts with less overshoots and noise disturbances and keeps an effective check on the disturbances out of jitter noises in PLL. The results show that during processing normal signals,this improved PLL reduces the standard deviation from 0. 010 69 cycle to 0. 007 63 cycle, and for weak signal processing,the phase jitter range and the Doppler shifts can be controlled within ± 17° and ±5 Hz as against ±25° and ＋ 15 Hz by the traditional PLL.展开更多
The quality element of a design class is important as it has a substantial listed influence on overall required quality of the software. The complexity and lengthy codes of program severely affect several quality meas...The quality element of a design class is important as it has a substantial listed influence on overall required quality of the software. The complexity and lengthy codes of program severely affect several quality measures, especially efficiency of the final delivered software. This paper does an appropriate review on efficiency of object oriented software, and suggests some relevant information about class design level efficiency. Program efficiency is an important factor to software quality. Moreover, if software efficiency analysis has been done in the early steps of the software creation process then it assures as a criterion to software quality. This article proposes a comprehensive research idea for estimation of the efficiency index. Subsequently, it does an extremely methodical review on design efficiency of software. After that, a design metric based efficiency estimation model at the design time has been proposed by creating the link between design properties of the program and efficiency criteria. Furthermore, the correlation is mapped among all with the help of statistical values for selected design properties and efficiency criteria. In addition, efficiency estimation model is empirically validated with try-out data.展开更多
Beam signals captured from a button-type pickup contain multidimensional information including the bunch charge,transverse position,bunch length,and longitudinal phase.A bunch phase monitor,which retrieves longitudina...Beam signals captured from a button-type pickup contain multidimensional information including the bunch charge,transverse position,bunch length,and longitudinal phase.A bunch phase monitor,which retrieves longitudinal phase information from a pickup signal at a bunch-by-bunch rate,has been developed at the Shanghai Synchrotron Radiation Facility.This paper introduces the basic principles,system setup,data processing method,and preliminary experimental results of this system.The systematic measurement error introduced by the limited system bandwidth,bunch length,and bunch charge variation was studied using simulation data.The random measurement uncertainty was evaluated using experimental beam data.The experimental result shows that the longitudinal phase resolution of this system is better than 1.0 ps.The first application,measuring the relationship between the longitudinal phase and bunch charge to determine the energy loss factor,was implemented,and the preliminary result is also discussed.展开更多
In this study, the allotropic phase transition and its effect on the magnetic behavior of Fe Co–7 wt%V alloy were investigated. It was found that c phase is observed in the microstructure in the as-cast condition, an...In this study, the allotropic phase transition and its effect on the magnetic behavior of Fe Co–7 wt%V alloy were investigated. It was found that c phase is observed in the microstructure in the as-cast condition, and it diminishes after severe cold rolling（90% reduction）. After annealing at temperatures higher than 500 up to 750 ℃, the c phase is observed in the structure, again. But, this phase is disappeared by annealing at temperatures above 750 ℃ due to the formation of vanadium-rich precipitates. Thermocalc software was used in order to elucidate the influence of vanadium percent on the stability of c phase in Fe–Co alloys. Also, magnetic studies showed that the saturation induction is reduced by annealing at temperatures from 500 up to 750 ℃, which is related to the formation of residual non-magnetic γ phase.展开更多
This study investigates the potential for enhancing the thermal performance of external walls insulation in warmer climates through the combination of phase change materials(PCMs)and bio-based materials,specifically h...This study investigates the potential for enhancing the thermal performance of external walls insulation in warmer climates through the combination of phase change materials(PCMs)and bio-based materials,specifically hemp wool and wood wool.Experimental tests using the heat flow method(HFM),and numerical simulations with ANSYS Fluent software were conducted to assess the dynamic thermal distribution and fluid-mechanical aspects of phase change materials(PCMs)within composite walls.The results demonstrate a notable reduction in peak indoor temperatures,achieving a 58%reduction with hemp wool with a close 40%reduction with wood wool when combined with PCMs.Fluid-mechanical analysis indicates that PCMs act as efficient indoor temperature regulators by storing excess heat during hot periods and releasing it later during phase transitions.Furthermore,the homogeneous distribution of the liquid fraction and natural convection during phase change contribute significantly to the improvement in heat transfer rates,resulting in a 96%reduction compared to hemp wool and wood wool without PCMs.展开更多
文摘A computer software to simulate the phase transformation during quenching is designed based on Avrami equation and Scheil additivity principle of incubation period. The isothermal transformation diagrams of supercooled austenite are described by cubic spline functions. This software is possess of a good graphic interface of Windows style, can simulate the whole process in austenite decomposition during continuous cooling. If the cooling rate was given, the fraction of various microstructures transformed of austenite decomposition during continuous cooling at any temperature can be calculated. The simulation results are checked with the quenching experiment of 45 steel. The results indicate that the simulation results are comparatively close to the experimental results.
基金Funded by the Key Project of Sichan Science Department (2012 JY0045, 2011SZZ029)Key Project of Sichan Education Department (10ZA060, 11ZA161)+1 种基金Key Project of Mianyang Municipal Science and Technology Bureau (10Y002-4)Special Project of MianYang Normal University (2011C02)
文摘Nd-rich phase plays an important role in the magnetic properties of sintered NdFeB alloy. The proportion of Nd-rich phase to all the other phases was calculated by using MATLAB 6.5 software. Especially, post-sintered alloy, post-high-temperature tempered alloy and post-high and low-temperature tempered alloy were analyzed. It was found that the proportion of Nd-rich phase in the three alloys based on SEM (scanning electron microscope) images was about 8.22%, 8.03% and 8.00%, respectively.
文摘This paper presents the design of a computational software system that enables solutions of multi-phase and multi-scale problems in mechanics. It demonstrated how mechanicians can design “process-driven” software systems directly, and that such efforts are more suitable in solving multi-phase or multi-scale problems, rather than utilizing the “data-driven” approaches of legacy network systems. Specifically, this paper demonstrates how this approach can be used to solve problems in flexible dynamics. Then it suggests a view of mechanics algorithms as ‘state equilibrium’ enforcers residing as servers, rather than as computer programs that solve field equations. It puts forth the need for identical input/output files to ensure widespread deployment on laptops. Then it presents an assessment of the laptop platform. A software system such as the one presented here can also be used to supply virtual environments, animations and entertainment/education software with physics.
文摘Software reliability modeling and prediction are important issues during software development, especially when one has to reach a desired reliability prior to software release. Various techniques, both static and dynamic, are used for reliability modeling and prediction in the context of software risk management. The single-phase Rayleigh model is a dynamic reliability model;however, it is not suitable for software release date prediction. We propose a new multi-phase truncated Rayleigh model and obtain parameter estimation using the nonlinear least squares method. The proposed model has been successfully tested in a large software company for several software projects. It is shown that the two-phase truncated Rayleigh model outperforms the traditional single-phase Rayleigh model in modeling weekly software defect arrival data. The model is useful for project management in planning release times and defect management.
基金National Natural Science Foundation of China(40671155)National High-tech Research and Development Programof China(2006AA12A108)Research Program of Hong Kong Polytech-nic University(G-U203)
文摘Suppressing jitter noises in a phase locked loop（ PLL） is of great importance in order to keep precise and continuous track of global positioning system （GPS）signals characterized by low carrier-to-noise ratio（ C/No ）. This article proposes and analyzes an improved Kalman-filter-based PLL to process weak carrier signals in GPS software receivers. After reviewing the optimal-bandwidth-based traditional second-order PLL, a Kalman-filter-based estimation algorithm is implemented for the new PLL by decorrelating the model error noises and the measurement noises. Finally,the efficiency of this new Kalman-filter-based PLL is verified by experimental data. Compared to the traditional second-order PLL, this new PLL is in position to make correct estimation of the carrier phase differences and Doppler shifts with less overshoots and noise disturbances and keeps an effective check on the disturbances out of jitter noises in PLL. The results show that during processing normal signals,this improved PLL reduces the standard deviation from 0. 010 69 cycle to 0. 007 63 cycle, and for weak signal processing,the phase jitter range and the Doppler shifts can be controlled within ± 17° and ±5 Hz as against ±25° and ＋ 15 Hz by the traditional PLL.
文摘The quality element of a design class is important as it has a substantial listed influence on overall required quality of the software. The complexity and lengthy codes of program severely affect several quality measures, especially efficiency of the final delivered software. This paper does an appropriate review on efficiency of object oriented software, and suggests some relevant information about class design level efficiency. Program efficiency is an important factor to software quality. Moreover, if software efficiency analysis has been done in the early steps of the software creation process then it assures as a criterion to software quality. This article proposes a comprehensive research idea for estimation of the efficiency index. Subsequently, it does an extremely methodical review on design efficiency of software. After that, a design metric based efficiency estimation model at the design time has been proposed by creating the link between design properties of the program and efficiency criteria. Furthermore, the correlation is mapped among all with the help of statistical values for selected design properties and efficiency criteria. In addition, efficiency estimation model is empirically validated with try-out data.
基金supported by the National Natural Science Foundation of China(Nos.11575282,11375255)
文摘Beam signals captured from a button-type pickup contain multidimensional information including the bunch charge,transverse position,bunch length,and longitudinal phase.A bunch phase monitor,which retrieves longitudinal phase information from a pickup signal at a bunch-by-bunch rate,has been developed at the Shanghai Synchrotron Radiation Facility.This paper introduces the basic principles,system setup,data processing method,and preliminary experimental results of this system.The systematic measurement error introduced by the limited system bandwidth,bunch length,and bunch charge variation was studied using simulation data.The random measurement uncertainty was evaluated using experimental beam data.The experimental result shows that the longitudinal phase resolution of this system is better than 1.0 ps.The first application,measuring the relationship between the longitudinal phase and bunch charge to determine the energy loss factor,was implemented,and the preliminary result is also discussed.
文摘In this study, the allotropic phase transition and its effect on the magnetic behavior of Fe Co–7 wt%V alloy were investigated. It was found that c phase is observed in the microstructure in the as-cast condition, and it diminishes after severe cold rolling（90% reduction）. After annealing at temperatures higher than 500 up to 750 ℃, the c phase is observed in the structure, again. But, this phase is disappeared by annealing at temperatures above 750 ℃ due to the formation of vanadium-rich precipitates. Thermocalc software was used in order to elucidate the influence of vanadium percent on the stability of c phase in Fe–Co alloys. Also, magnetic studies showed that the saturation induction is reduced by annealing at temperatures from 500 up to 750 ℃, which is related to the formation of residual non-magnetic γ phase.
文摘This study investigates the potential for enhancing the thermal performance of external walls insulation in warmer climates through the combination of phase change materials(PCMs)and bio-based materials,specifically hemp wool and wood wool.Experimental tests using the heat flow method(HFM),and numerical simulations with ANSYS Fluent software were conducted to assess the dynamic thermal distribution and fluid-mechanical aspects of phase change materials(PCMs)within composite walls.The results demonstrate a notable reduction in peak indoor temperatures,achieving a 58%reduction with hemp wool with a close 40%reduction with wood wool when combined with PCMs.Fluid-mechanical analysis indicates that PCMs act as efficient indoor temperature regulators by storing excess heat during hot periods and releasing it later during phase transitions.Furthermore,the homogeneous distribution of the liquid fraction and natural convection during phase change contribute significantly to the improvement in heat transfer rates,resulting in a 96%reduction compared to hemp wool and wood wool without PCMs.
