In recent years, Z-source inverters (ZSI) have been proposed as an replacement power conversion concept which it has both voltage buck and boost abilities. In addition, ZSI doesn’t require dead-time to protection sho...In recent years, Z-source inverters (ZSI) have been proposed as an replacement power conversion concept which it has both voltage buck and boost abilities. In addition, ZSI doesn’t require dead-time to protection short circuit at two switches any of the same phase leg in the inverter bridge and to achieve optimal harmonic of current, voltage. This paper presents two different control methods (CM) for ZSI. The aim of this study to compare between two modulation methods, there are modi?ed space vector pulse width modulation method (MSVM) and the simple boost control (SBC) about the unique harmonic performance features, the total average and peak switching device power of the inverter system. In addition, this paper also analyzes about the ability exceed modulation index in linear region of two CM using MATLAB/Simulink.展开更多
A palladium catalyst immobilized on superparaganetic nanoparticles was prepared with a palladium loading of 0.30 mmol/g. The catalyst was characterized using X-ray diffraction, scanning electron microscopy, transmissi...A palladium catalyst immobilized on superparaganetic nanoparticles was prepared with a palladium loading of 0.30 mmol/g. The catalyst was characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, thermogravimetric analysis, Fourier transform infrared, atomic absorption spectrophotometry, and nitrogen adsorption. The immobilized palladium catalyst was an efficient catalyst without added phosphine ligands for the Suzuki cross-coupling reaction of several aryl bromides with phenylboronic acid. The recovery of catalyst was simply by magnetic decantation in the presence of a magnet. The immobilized palladium catalyst can be reused many times without significant degradation in catalytic activity. No leaching of active palladium species into the reaction solution was detected.展开更多
The aim of this work was to study the influence of CaCO3 in both tensile and flexural mechanical properties of a PET(polyethylene terephthalate)/PP(polypropylene).Four compositions of PET/PP/CaCO3 blend were prepared ...The aim of this work was to study the influence of CaCO3 in both tensile and flexural mechanical properties of a PET(polyethylene terephthalate)/PP(polypropylene).Four compositions of PET/PP/CaCO3 blend were prepared by injection molding with CaCO3 content of 0,2,4 and 6 wt%.The samples were cut according to the ASTM(American Society for Testing and Materials)standard and tested by using universal testing equipment.The results show that the mechanical properties of the PET/PP/CaCO3 composites with 2%and 4 wt%of CaCO3 composition were better than that of the PET/PP composites.While the content of CaCO3 is 6 wt%,the serious phase separation between PET and PP resulted in poor mechanical properties of the PET/PP/CaCO3 samples.This study shows that CaCO3 has played a role to improve the tensile and flexural properties of the mixing product if it is present only in a small amount.展开更多
Radiative decays D((s))*→D((s))γare revisited in light of new experimental data from the BaBar and BESⅢCollaborations.The radiative couplings gD*Dγencoding nonperturbative QCD effects are calculated in the framewo...Radiative decays D((s))*→D((s))γare revisited in light of new experimental data from the BaBar and BESⅢCollaborations.The radiative couplings gD*Dγencoding nonperturbative QCD effects are calculated in the framework of the covariant confined quark model developed by us.We compare our results with other theoretical studies and experimental data.The couplings(in GeV-1)|g(D*+D+γ)|=0.45(9)and|g(D*0D0γ)|=1.72(34)calculated in our model agree with the corresponding experimental data|g(D*+D+γ)|=0.47(7)and|g(D*0D0γ)|=1.77(16).The most interesting case is the decay Ds*→Dsγ,for which a recent prediction based on light-cone sum rules at next-to-leading order|gDs*Dsγ|=0.60(19)deviates from the first(and only to date)lattice QCD result|gDs*Dsγ|=0.11(2)at nearly3σ.Our calculation yields|gDs*Dsγ|=0.29(6),which falls somehow between the two mentioned results,although it is larger than those predicted in other studies using quark models or QCD sum rules.展开更多
We investigate a new numerical procedure based on a bubble-enriched finite element formulation in combination with the implicit backward Euler scheme for nonlinear analysis of strip footings and stability of slopes.Th...We investigate a new numerical procedure based on a bubble-enriched finite element formulation in combination with the implicit backward Euler scheme for nonlinear analysis of strip footings and stability of slopes.The soil body is modeled as a perfect plastic Mohr-Coulomb material.The displacement field is approximated by a 4-node quadrilateral element discretization enhanced with bubble modes.Collapse loads and failure mechanisms in cohesive frictional soil are determined by solving a few Newton-Raphson iterations.Numerical results of the present approach are verified by both analytical solutions and other numerical solutions available in the literature.展开更多
Purpose-Artificial neural network(ANN)is considered a good solution for building non-linear relationship between input and output parameters,which is suitable for solving production back allocation,which is the most i...Purpose-Artificial neural network(ANN)is considered a good solution for building non-linear relationship between input and output parameters,which is suitable for solving production back allocation,which is the most important step for production planning of petroleum mine.The purpose of this paper is to suggest a solution for solving production back allocation problem at Samarang petrol mine based on ANN approach.Design/methodology/approach-In this study,well operational parameters’surveillance was conducted and ANN was used to build relationships between operation parameters and production rates.Experimental method is used for testing and evaluating the possibility of using ANN for supporting production planning at Samarang mine.Findings-Consequently,the proposed ANN solution can increase the accuracy of predicted values and could be used for supporting production planning at Samarang mine.Because ANN uses well test data for training and predicting(without adding new devices),it could be a feasible and cheap solution.Research limitations/implications-There is a need for applying other methods,such as:support machine vector,non-linear autoregressive models,etc.for better evaluation of ANN solution.Practical implications-The ANN models helped operation engineers to understand well production performance and make decision to improve production plan in timely manner.This solution could be generalized for the whole mine or to similar petroleum mines in practice.Originality/value-This paper aims to propose a solution based on ANN for solving production back allocation problem of petroleum industry.The solution is tested at Samarang mine.展开更多
文摘In recent years, Z-source inverters (ZSI) have been proposed as an replacement power conversion concept which it has both voltage buck and boost abilities. In addition, ZSI doesn’t require dead-time to protection short circuit at two switches any of the same phase leg in the inverter bridge and to achieve optimal harmonic of current, voltage. This paper presents two different control methods (CM) for ZSI. The aim of this study to compare between two modulation methods, there are modi?ed space vector pulse width modulation method (MSVM) and the simple boost control (SBC) about the unique harmonic performance features, the total average and peak switching device power of the inverter system. In addition, this paper also analyzes about the ability exceed modulation index in linear region of two CM using MATLAB/Simulink.
基金supported by the Ho Chi Minh City Department of Science and Technology, Viet Nam
文摘A palladium catalyst immobilized on superparaganetic nanoparticles was prepared with a palladium loading of 0.30 mmol/g. The catalyst was characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, thermogravimetric analysis, Fourier transform infrared, atomic absorption spectrophotometry, and nitrogen adsorption. The immobilized palladium catalyst was an efficient catalyst without added phosphine ligands for the Suzuki cross-coupling reaction of several aryl bromides with phenylboronic acid. The recovery of catalyst was simply by magnetic decantation in the presence of a magnet. The immobilized palladium catalyst can be reused many times without significant degradation in catalytic activity. No leaching of active palladium species into the reaction solution was detected.
文摘The aim of this work was to study the influence of CaCO3 in both tensile and flexural mechanical properties of a PET(polyethylene terephthalate)/PP(polypropylene).Four compositions of PET/PP/CaCO3 blend were prepared by injection molding with CaCO3 content of 0,2,4 and 6 wt%.The samples were cut according to the ASTM(American Society for Testing and Materials)standard and tested by using universal testing equipment.The results show that the mechanical properties of the PET/PP/CaCO3 composites with 2%and 4 wt%of CaCO3 composition were better than that of the PET/PP composites.While the content of CaCO3 is 6 wt%,the serious phase separation between PET and PP resulted in poor mechanical properties of the PET/PP/CaCO3 samples.This study shows that CaCO3 has played a role to improve the tensile and flexural properties of the mixing product if it is present only in a small amount.
基金Supported by Ho Chi Minh City University of Technology and Education(T2022-26)。
文摘Radiative decays D((s))*→D((s))γare revisited in light of new experimental data from the BaBar and BESⅢCollaborations.The radiative couplings gD*Dγencoding nonperturbative QCD effects are calculated in the framework of the covariant confined quark model developed by us.We compare our results with other theoretical studies and experimental data.The couplings(in GeV-1)|g(D*+D+γ)|=0.45(9)and|g(D*0D0γ)|=1.72(34)calculated in our model agree with the corresponding experimental data|g(D*+D+γ)|=0.47(7)and|g(D*0D0γ)|=1.77(16).The most interesting case is the decay Ds*→Dsγ,for which a recent prediction based on light-cone sum rules at next-to-leading order|gDs*Dsγ|=0.60(19)deviates from the first(and only to date)lattice QCD result|gDs*Dsγ|=0.11(2)at nearly3σ.Our calculation yields|gDs*Dsγ|=0.29(6),which falls somehow between the two mentioned results,although it is larger than those predicted in other studies using quark models or QCD sum rules.
文摘We investigate a new numerical procedure based on a bubble-enriched finite element formulation in combination with the implicit backward Euler scheme for nonlinear analysis of strip footings and stability of slopes.The soil body is modeled as a perfect plastic Mohr-Coulomb material.The displacement field is approximated by a 4-node quadrilateral element discretization enhanced with bubble modes.Collapse loads and failure mechanisms in cohesive frictional soil are determined by solving a few Newton-Raphson iterations.Numerical results of the present approach are verified by both analytical solutions and other numerical solutions available in the literature.
基金Many thanks to employees and managers of Samarang mine,who provided data for analysis or participated in several interviews of this research for discussing possibility of applying neural network in improving production plan at Samarang mine.
文摘Purpose-Artificial neural network(ANN)is considered a good solution for building non-linear relationship between input and output parameters,which is suitable for solving production back allocation,which is the most important step for production planning of petroleum mine.The purpose of this paper is to suggest a solution for solving production back allocation problem at Samarang petrol mine based on ANN approach.Design/methodology/approach-In this study,well operational parameters’surveillance was conducted and ANN was used to build relationships between operation parameters and production rates.Experimental method is used for testing and evaluating the possibility of using ANN for supporting production planning at Samarang mine.Findings-Consequently,the proposed ANN solution can increase the accuracy of predicted values and could be used for supporting production planning at Samarang mine.Because ANN uses well test data for training and predicting(without adding new devices),it could be a feasible and cheap solution.Research limitations/implications-There is a need for applying other methods,such as:support machine vector,non-linear autoregressive models,etc.for better evaluation of ANN solution.Practical implications-The ANN models helped operation engineers to understand well production performance and make decision to improve production plan in timely manner.This solution could be generalized for the whole mine or to similar petroleum mines in practice.Originality/value-This paper aims to propose a solution based on ANN for solving production back allocation problem of petroleum industry.The solution is tested at Samarang mine.