A new type of double salient starter/generator is presented, which can be used in aircraft Low Voltage Direct Current (LVDC), Variable Speed Constant Frequency (VSCF) and High Voltage Direct Current (HVDC) systems. Th...A new type of double salient starter/generator is presented, which can be used in aircraft Low Voltage Direct Current (LVDC), Variable Speed Constant Frequency (VSCF) and High Voltage Direct Current (HVDC) systems. The operational theory of the motor and generator is analyzed, and corresponding control strategies are given. An 18kW prototype has been implemented to verify the system performance. It is shown that the DSM S/G system possesses simple structure, high efficiency and flexible control. It is ap...展开更多
This paper focuses on the simulation and test of the switched reluctance starter/generator systems. Through the emulational analysis of the initial starting torque, the optimal turn-on section of the power switches is...This paper focuses on the simulation and test of the switched reluctance starter/generator systems. Through the emulational analysis of the initial starting torque, the optimal turn-on section of the power switches is discovered. The fundamental theory of the generating operation is analyzed with the linearity model, and a new method is presented based on voltage pulse width modulation for the generating mode control. Through the steady-state and optimized emulation of the output power and system efficiency, the optimizational control approach for the generating mode over a wide speed range is introduced. At last, the test of the 3KW prototype system shows that the dynamic and static performance of this system is fine.展开更多
More Electrical Aircraft(MEA)which replaces the hydraulic and pneumatic power by electrical power leads to reducing emissions and fuel consumption.The MEA concept has led to a growing use of the starter/generator(S/G)...More Electrical Aircraft(MEA)which replaces the hydraulic and pneumatic power by electrical power leads to reducing emissions and fuel consumption.The MEA concept has led to a growing use of the starter/generator(S/G)system.Permanent magnet(PM)machines have been gaining interests for aircraft S/G system application over the last few years.This is mainly due to the several advantages,including high power density,high efficiency and high speed ability.The shortcoming of the PM machines is the de-excitation problem in case of a failure,which is a main issue for the aircraft application.However,by using a PM machine with high reactance or multiphase configuration,the fault-tolerant ability can be improved.In terms of the aircraft S/G system,this paper is going to present a comprehensive analysis of PM machines.Firstly,the state-of-the-art of PM starter/generator(PMS/G)is summarized and the basic structure of PMS/G system is analyzed.Next,key technologies of the PMS/G system are summarized and analyzed.Finally,a flux weakening fault protection strategy that is used to suppress the turn-to-turn short circuit(SC)current is studied,simulated and verified.With the breakthrough of key technologies based on the development of high temperature electromagnetic material and high temperature power electronics,the PMS/G will be a potential candidate for aircraft S/G system including the embedded power generation system.展开更多
The effects of 5 lactic acid bacteria(LAB)fermentation on the pasting properties of glutinous rice flour were compared,and suitable fermentation strains were selected based on the changes of viscosity,setback value,an...The effects of 5 lactic acid bacteria(LAB)fermentation on the pasting properties of glutinous rice flour were compared,and suitable fermentation strains were selected based on the changes of viscosity,setback value,and breakdown value to prepare LAB compound starter cultures.The results revealed that Latilactobacillus sakei HSD004 and Lacticaseibacillus rhamnosus HSD005 had apparent advantages in increasing the viscosity and reducing the setback and breakdown values of glutinous rice flour.In particular,the compound starter created using the two abovementioned LAB in the ratio of 3:1 had better performance than that using a single LAB in improving the pasting properties and increasing the water and oil absorption capacity of glutinous rice flour.Moreover,the gelatinization enthalpy of the fermented samples increased significantly.For frozen glutinous rice dough stored for 28 days,the viscoelasticity of frozen dough prepared by compound starter was better than that of control dough,and the freezable water content was lower than that of control dough.These results indicate that compound LAB fermentation is a promising technology in the glutinous rice-based food processing industry,which has significance for its application.展开更多
According to specific performance requirements,an integrated switched reluctance starter/generator system,which can start the engine and supply electrical energy to the loads,is designed and manufactured for the unman...According to specific performance requirements,an integrated switched reluctance starter/generator system,which can start the engine and supply electrical energy to the loads,is designed and manufactured for the unmanned aerial vehicle.Considering the required starting torque and speed range,the geometrical dimensions of the switched reluctance machine are calculated based on the output equation and further optimized with finite element analysis,and the flux-linkage,inductance and static torque characteristics are illustrated.To verify the performances of the designed system,detailed simulation with the model considering piston engine and experiment using the test bench are carried out.展开更多
The information of the field current is essential for the brushless synchronous starter/generator system,which determines the performance and health status of this system.However,since the field winding of the main ma...The information of the field current is essential for the brushless synchronous starter/generator system,which determines the performance and health status of this system.However,since the field winding of the main machine is installed in the rotor part,the measurement of the field current in this brushless system seem impossible.Considering that,the field current might be affected by the rectifier mode,the field current estimation method in different rectifier mode is studied in this paper.The main exciter(ME)rotor currents were restructured based on the ME flux equations.With these restructured rotor currents,the field current in different rectifier commutation mode is analyzed,then the field current estimation method considering the rectifier mode can be obtained.The experiments in different rectifier modes are carried out to verify the proposed method.展开更多
The basic concepts and advantages of more/all electric aircraft （M/AEA） are briefly addressed. The combined starter/generator （CS/G） system is introduced as a key technology to enable M/AEA. Some important perform...The basic concepts and advantages of more/all electric aircraft （M/AEA） are briefly addressed. The combined starter/generator （CS/G） system is introduced as a key technology to enable M/AEA. Some important performance requirements for CS/G system are obtained. Based on these requirements, a high speed switched reluctance machine （SRM） is designed to operate as a starter/generator. The entire design process is mainly divided into two stages： electromagnetic design and thermal design. In electromagnetic design stage, the electromagnetic structure and dimensions of the machine and the number of phase winding turns per pole are obtained; the topology and main technical details of the converter are briefly introduced as well. In thermal design stage, a liquid-cooling system is designed based on the thermal analysis of the machine. In the end, the performances of the designed SRM are basically verified by simulation. To get high performances, the exciting angles are optimized in two different operating modes respectively, and the optimized performances in the motoring mode are given as well.展开更多
Mold spoilage and nutrition enrichment are major concerns of Chinese steamed bread,and using functional lactic acid bacteria as starter to play the role of in-situ preservation and nutritional fortification was a prom...Mold spoilage and nutrition enrichment are major concerns of Chinese steamed bread,and using functional lactic acid bacteria as starter to play the role of in-situ preservation and nutritional fortification was a promising alternative.Hence,Lactiplantibacillus plantarum P10 capable of inhibiting spoilage microorganisms and producing γ-aminobutyric acid(GABA)(380 mg/L)was screened from Chinese pickle.Metabolomics analysis showed that P10 produced key antimicrobial metabolites mainly including ten organic acids,aldehyde,alkaloid.Besides,P10 might exhibit health beneficial effects such as degrading cholesterol,lowering blood glucose and reducing uric acid due to the production of deoxycholic acid and Ile-Pro-Ile,and the degradation of purine.Finally,the promising application potential of P10 was evidenced in steamed bread with extended shelf life,excellent anti-aging effect,and 24.5-fold enrichment of GABA.Conclusively,this investigation could provide scientific basis for the application of P10 as a functional starter in steamed bread.展开更多
Although coagulase-negative Staphylococcus(CNS),along with technological activities,plays a key role in fermented sausage flavour and nutrient production,the molecular mechanism of these activities remains elusive.In ...Although coagulase-negative Staphylococcus(CNS),along with technological activities,plays a key role in fermented sausage flavour and nutrient production,the molecular mechanism of these activities remains elusive.In this study,18 CNS strains with high proteolytic activity were isolated from Chinese Dong fermented pork(Nanx Wudl),and their technological and transcriptomic properties were investigated.After biochemical identification and genetic analysis,their technological properties,including nitrate reductase,catalase,antioxidant,and lipolytic activities and their growth under varying temperatures,salt concentrations,and p H levels were evaluated.Their aroma-producing potential was also determined in a model medium resembling fermented sausages.Transcriptomic analysis was performed using the most promising isolates.Biochemical identification and 16S rDNA sequencing revealed that the 18 Staphylococcus strains belonged to Staphylococcus xylosus,Staphylococcus saprophyticus,Staphylococcus carnosus,Staphylococcus sciuri,and Staphylococcus equorum.In terms of technological properties,16 strains showed a nitrate-reducing ability,while 11 strains had a lipolytic activity.All strains exhibited superoxide dismutase(SOD)and catalase activities;four strains displayed an SOD activity of>50%.They also tolerated 10%NaCl and 150 mg/kg of nitrite.They showed significant differences in ketone and acid production.The transcriptomic analysis of S.xylosus strains Sx3 and Sx6,which were selected because of their excellent enzymatic activities and aroma-producing ability,revealed the remarkable effect of genes related to pyruvate catabolism and amino acid metabolism on aroma generation.Therefore,this study provided valuable insights into the metabolic mechanisms underlying the technological properties of CNS and identified promising candidates as starter cultures in fermented sausage manufacturing.展开更多
The objective of this study was to explore the effects of the inoculation of mixed starter cultures of Lactobacillus and Staphylococcus(labeled L-S)on microbial community and flavor in fermented sausages during the ri...The objective of this study was to explore the effects of the inoculation of mixed starter cultures of Lactobacillus and Staphylococcus(labeled L-S)on microbial community and flavor in fermented sausages during the ripening process.Culture-dependent(colony count)and culture-independent(high-throughput sequencing)methods were employed to evaluate bacterial communities.Volatile compounds were identified by gas chromatography-mass spectrometry,and the results were analyzed by principal component analysis(PCA).The identified bacteria with high relative abundance included Lactobacillus and Pediococcus,and the relative abundances of Leuconostoc and Weissella in fermented sausages were remarkably decreased at the end of the ripening process.At the end of ripening,2-nonenal,tetradecanal,ethylstearate and terpinyl acetate played substantial roles in the flavor development of the L-S fermented sausages.Sensory evaluation showed a high score in the L-S fermented sausages.Sausages can be inoculated with L-S starter culture to improve the safety and flavor of meat products.展开更多
Effects of a starter culture composed of Lactobacillus sakei,Pediococcus pentosaceus,Staphylococcus xylosus and S.carnosus at the ratios(m/m)of 1:1:1:1 on bacterial profile and biogenic amine accumulation in Chinese S...Effects of a starter culture composed of Lactobacillus sakei,Pediococcus pentosaceus,Staphylococcus xylosus and S.carnosus at the ratios(m/m)of 1:1:1:1 on bacterial profile and biogenic amine accumulation in Chinese Sichuan sausages were demonstrated.In starter culture-inoculated sausages,Lactobacillus spp.,Pediococcus spp.and Staphylococcus spp.were predominant bacterial genus and their relative abundances ranged from 70.14%to 25.98%,57.66%to 14.08%,and 15.71%to 13.40%during fermentation,respectively.Accordingly,Lactobacillus spp.and Weissella spp.were predominant bacterial genus and their relative abundances ranged from 63.14%to 24.70%and 49.40%to 11.96%during spontaneous fermentation,respectively.Furthermore,the abundances of undesirable microorganisms such as Yersinia spp.,Enterobacter spp.,Acietobacter spp.and Psychrobacter spp.were lower than that of the control.The levels of histamine,putrescine,tyramine and cadaverine in Chinese Sichuan sausages with starter cultures inoculation were significantly lower(P<0.05)than that of the control,and were decreased by 83.09%,69.38%,51.87%and 57.20%,respectively,at the end of the ripening.These results revealed that the starter cultures inoculation was a better alternative for microbial quality improvement and biogenic amine reduction of Chinese Sichuan sausages with good sensory attributes.展开更多
文摘A new type of double salient starter/generator is presented, which can be used in aircraft Low Voltage Direct Current (LVDC), Variable Speed Constant Frequency (VSCF) and High Voltage Direct Current (HVDC) systems. The operational theory of the motor and generator is analyzed, and corresponding control strategies are given. An 18kW prototype has been implemented to verify the system performance. It is shown that the DSM S/G system possesses simple structure, high efficiency and flexible control. It is ap...
文摘This paper focuses on the simulation and test of the switched reluctance starter/generator systems. Through the emulational analysis of the initial starting torque, the optimal turn-on section of the power switches is discovered. The fundamental theory of the generating operation is analyzed with the linearity model, and a new method is presented based on voltage pulse width modulation for the generating mode control. Through the steady-state and optimized emulation of the output power and system efficiency, the optimizational control approach for the generating mode over a wide speed range is introduced. At last, the test of the 3KW prototype system shows that the dynamic and static performance of this system is fine.
基金This work was supported in part by National Natural Science Foundation for Excellent Young Scholar of China under Award 51622704Jiangsu Provincial Science Funds for Distinguished Young Scientists under Award BK20150033.
文摘More Electrical Aircraft(MEA)which replaces the hydraulic and pneumatic power by electrical power leads to reducing emissions and fuel consumption.The MEA concept has led to a growing use of the starter/generator(S/G)system.Permanent magnet(PM)machines have been gaining interests for aircraft S/G system application over the last few years.This is mainly due to the several advantages,including high power density,high efficiency and high speed ability.The shortcoming of the PM machines is the de-excitation problem in case of a failure,which is a main issue for the aircraft application.However,by using a PM machine with high reactance or multiphase configuration,the fault-tolerant ability can be improved.In terms of the aircraft S/G system,this paper is going to present a comprehensive analysis of PM machines.Firstly,the state-of-the-art of PM starter/generator(PMS/G)is summarized and the basic structure of PMS/G system is analyzed.Next,key technologies of the PMS/G system are summarized and analyzed.Finally,a flux weakening fault protection strategy that is used to suppress the turn-to-turn short circuit(SC)current is studied,simulated and verified.With the breakthrough of key technologies based on the development of high temperature electromagnetic material and high temperature power electronics,the PMS/G will be a potential candidate for aircraft S/G system including the embedded power generation system.
基金supported by the National Key Research and Development Program of China(2021YFD2100902-3)the National Natural Science Foundation of China(32072258)+5 种基金Major Science and Technology Program of Heilongjiang(2020ZX08B02)Harbin University of Commerce“Young Innovative Talents”Support Program(2019CX062020CX262020CX27)the Central Financial Support for the Development of Local Colleges and Universities,Graduate Innovation Research Project of Harbin University of Commerce(YJSCX2021-698HSD)Training plan of Young Innovative Talents in Universities of Heilongjiang(UNPYSCT-2020218).
文摘The effects of 5 lactic acid bacteria(LAB)fermentation on the pasting properties of glutinous rice flour were compared,and suitable fermentation strains were selected based on the changes of viscosity,setback value,and breakdown value to prepare LAB compound starter cultures.The results revealed that Latilactobacillus sakei HSD004 and Lacticaseibacillus rhamnosus HSD005 had apparent advantages in increasing the viscosity and reducing the setback and breakdown values of glutinous rice flour.In particular,the compound starter created using the two abovementioned LAB in the ratio of 3:1 had better performance than that using a single LAB in improving the pasting properties and increasing the water and oil absorption capacity of glutinous rice flour.Moreover,the gelatinization enthalpy of the fermented samples increased significantly.For frozen glutinous rice dough stored for 28 days,the viscoelasticity of frozen dough prepared by compound starter was better than that of control dough,and the freezable water content was lower than that of control dough.These results indicate that compound LAB fermentation is a promising technology in the glutinous rice-based food processing industry,which has significance for its application.
基金This work was supported by the Key Research and Development Plan of Shaanxi Province under Grant 2018GY-185,Xi'an Science and Technology Plan under Grant 2017086CG/RC049(XBGY002)the ASN Innovation Development Fund under Grant ASN-IF2015-3110the Fundamental Research Funds for the Central Universities under Grants 3102017AX007.
文摘According to specific performance requirements,an integrated switched reluctance starter/generator system,which can start the engine and supply electrical energy to the loads,is designed and manufactured for the unmanned aerial vehicle.Considering the required starting torque and speed range,the geometrical dimensions of the switched reluctance machine are calculated based on the output equation and further optimized with finite element analysis,and the flux-linkage,inductance and static torque characteristics are illustrated.To verify the performances of the designed system,detailed simulation with the model considering piston engine and experiment using the test bench are carried out.
基金supported in part by the Natural Science Foundation of Shaanxi Province under Grant 2023JCQN0534in part by the Natural Science Foundation of Shaanxi Provincial Department of Education under Grant 23JK0660in part by the Xi’an Municipal Bureau of Science and Technology under Grant 24GXF0085。
文摘The information of the field current is essential for the brushless synchronous starter/generator system,which determines the performance and health status of this system.However,since the field winding of the main machine is installed in the rotor part,the measurement of the field current in this brushless system seem impossible.Considering that,the field current might be affected by the rectifier mode,the field current estimation method in different rectifier mode is studied in this paper.The main exciter(ME)rotor currents were restructured based on the ME flux equations.With these restructured rotor currents,the field current in different rectifier commutation mode is analyzed,then the field current estimation method considering the rectifier mode can be obtained.The experiments in different rectifier modes are carried out to verify the proposed method.
文摘The basic concepts and advantages of more/all electric aircraft （M/AEA） are briefly addressed. The combined starter/generator （CS/G） system is introduced as a key technology to enable M/AEA. Some important performance requirements for CS/G system are obtained. Based on these requirements, a high speed switched reluctance machine （SRM） is designed to operate as a starter/generator. The entire design process is mainly divided into two stages： electromagnetic design and thermal design. In electromagnetic design stage, the electromagnetic structure and dimensions of the machine and the number of phase winding turns per pole are obtained; the topology and main technical details of the converter are briefly introduced as well. In thermal design stage, a liquid-cooling system is designed based on the thermal analysis of the machine. In the end, the performances of the designed SRM are basically verified by simulation. To get high performances, the exciting angles are optimized in two different operating modes respectively, and the optimized performances in the motoring mode are given as well.
基金financially supported by Natural Science Foundations of Hebei Province(C2022208003)Youth Top Talent Plan in Hebei Province。
文摘Mold spoilage and nutrition enrichment are major concerns of Chinese steamed bread,and using functional lactic acid bacteria as starter to play the role of in-situ preservation and nutritional fortification was a promising alternative.Hence,Lactiplantibacillus plantarum P10 capable of inhibiting spoilage microorganisms and producing γ-aminobutyric acid(GABA)(380 mg/L)was screened from Chinese pickle.Metabolomics analysis showed that P10 produced key antimicrobial metabolites mainly including ten organic acids,aldehyde,alkaloid.Besides,P10 might exhibit health beneficial effects such as degrading cholesterol,lowering blood glucose and reducing uric acid due to the production of deoxycholic acid and Ile-Pro-Ile,and the degradation of purine.Finally,the promising application potential of P10 was evidenced in steamed bread with extended shelf life,excellent anti-aging effect,and 24.5-fold enrichment of GABA.Conclusively,this investigation could provide scientific basis for the application of P10 as a functional starter in steamed bread.
基金the financial support of the National Natural Science Foundation of China(32102016)the Taishan Industrial Experts Program。
文摘Although coagulase-negative Staphylococcus(CNS),along with technological activities,plays a key role in fermented sausage flavour and nutrient production,the molecular mechanism of these activities remains elusive.In this study,18 CNS strains with high proteolytic activity were isolated from Chinese Dong fermented pork(Nanx Wudl),and their technological and transcriptomic properties were investigated.After biochemical identification and genetic analysis,their technological properties,including nitrate reductase,catalase,antioxidant,and lipolytic activities and their growth under varying temperatures,salt concentrations,and p H levels were evaluated.Their aroma-producing potential was also determined in a model medium resembling fermented sausages.Transcriptomic analysis was performed using the most promising isolates.Biochemical identification and 16S rDNA sequencing revealed that the 18 Staphylococcus strains belonged to Staphylococcus xylosus,Staphylococcus saprophyticus,Staphylococcus carnosus,Staphylococcus sciuri,and Staphylococcus equorum.In terms of technological properties,16 strains showed a nitrate-reducing ability,while 11 strains had a lipolytic activity.All strains exhibited superoxide dismutase(SOD)and catalase activities;four strains displayed an SOD activity of>50%.They also tolerated 10%NaCl and 150 mg/kg of nitrite.They showed significant differences in ketone and acid production.The transcriptomic analysis of S.xylosus strains Sx3 and Sx6,which were selected because of their excellent enzymatic activities and aroma-producing ability,revealed the remarkable effect of genes related to pyruvate catabolism and amino acid metabolism on aroma generation.Therefore,this study provided valuable insights into the metabolic mechanisms underlying the technological properties of CNS and identified promising candidates as starter cultures in fermented sausage manufacturing.
基金supported by the Natural Science Research Projects of Shanxi Province (20210302123400) in ChinaAgricultural Valley Construction Research Project of Shanxi Province (SXNGJSKYZX201903)Key Science and Technology Programs in Agriculture of Shanxi Province (201903D211008)
文摘The objective of this study was to explore the effects of the inoculation of mixed starter cultures of Lactobacillus and Staphylococcus(labeled L-S)on microbial community and flavor in fermented sausages during the ripening process.Culture-dependent(colony count)and culture-independent(high-throughput sequencing)methods were employed to evaluate bacterial communities.Volatile compounds were identified by gas chromatography-mass spectrometry,and the results were analyzed by principal component analysis(PCA).The identified bacteria with high relative abundance included Lactobacillus and Pediococcus,and the relative abundances of Leuconostoc and Weissella in fermented sausages were remarkably decreased at the end of the ripening process.At the end of ripening,2-nonenal,tetradecanal,ethylstearate and terpinyl acetate played substantial roles in the flavor development of the L-S fermented sausages.Sensory evaluation showed a high score in the L-S fermented sausages.Sausages can be inoculated with L-S starter culture to improve the safety and flavor of meat products.
基金supported by National Natural Science Foundation of China(31772093)Key innovation projects of Chengdu Science and Technology(2019-YF05-00066-SN)Key Laboratory of Collaborative Control and Remediation of Soil and Water Pollution(GHBK-003)。
文摘Effects of a starter culture composed of Lactobacillus sakei,Pediococcus pentosaceus,Staphylococcus xylosus and S.carnosus at the ratios(m/m)of 1:1:1:1 on bacterial profile and biogenic amine accumulation in Chinese Sichuan sausages were demonstrated.In starter culture-inoculated sausages,Lactobacillus spp.,Pediococcus spp.and Staphylococcus spp.were predominant bacterial genus and their relative abundances ranged from 70.14%to 25.98%,57.66%to 14.08%,and 15.71%to 13.40%during fermentation,respectively.Accordingly,Lactobacillus spp.and Weissella spp.were predominant bacterial genus and their relative abundances ranged from 63.14%to 24.70%and 49.40%to 11.96%during spontaneous fermentation,respectively.Furthermore,the abundances of undesirable microorganisms such as Yersinia spp.,Enterobacter spp.,Acietobacter spp.and Psychrobacter spp.were lower than that of the control.The levels of histamine,putrescine,tyramine and cadaverine in Chinese Sichuan sausages with starter cultures inoculation were significantly lower(P<0.05)than that of the control,and were decreased by 83.09%,69.38%,51.87%and 57.20%,respectively,at the end of the ripening.These results revealed that the starter cultures inoculation was a better alternative for microbial quality improvement and biogenic amine reduction of Chinese Sichuan sausages with good sensory attributes.
