This study investigated the physicochemical properties,enzyme activities,volatile flavor components,microbial communities,and sensory evaluation of high-temperature Daqu(HTD)during the maturation process,and a standar...This study investigated the physicochemical properties,enzyme activities,volatile flavor components,microbial communities,and sensory evaluation of high-temperature Daqu(HTD)during the maturation process,and a standard system was established for comprehensive quality evaluation of HTD.There were obvious changes in the physicochemical properties,enzyme activities,and volatile flavor components at different storage periods,which affected the sensory evaluation of HTD to a certain extent.The results of high-throughput sequencing revealed significant microbial diversity,and showed that the bacterial community changed significantly more than did the fungal community.During the storage process,the dominant bacterial genera were Kroppenstedtia and Thermoascus.The correlation between dominant microorganisms and quality indicators highlighted their role in HTD quality.Lactococcus,Candida,Pichia,Paecilomyces,and protease activity played a crucial role in the formation of isovaleraldehyde.Acidic protease activity had the greatest impact on the microbial community.Moisture promoted isobutyric acid generation.Furthermore,the comprehensive quality evaluation standard system was established by the entropy weight method combined with multi-factor fuzzy mathematics.Consequently,this study provides innovative insights for comprehensive quality evaluation of HTD during storage and establishes a groundwork for scientific and rational storage of HTD and quality control of sauce-flavor Baijiu.展开更多
To investigate the influence of temperature on the physical,mechanical and acoustic emission characteristics of granites,uniaxial compression test,variable-angle shear test,acoustic emission signal monitoring and the ...To investigate the influence of temperature on the physical,mechanical and acoustic emission characteristics of granites,uniaxial compression test,variable-angle shear test,acoustic emission signal monitoring and the measurement of physical parameters including mass,size and P-wave velocity were carried out on granite samples treated at temperatures T ranging from 25 to 900℃.The results show that the density and P-wave velocity decrease gradually with increasing T.As the temperature increases,the peak compressive stress decreases while the peak strain increases,due to the fact that a high temperature induces the escaping of waters within granites,the expanding of mineral grains and the generations of fractures.With the increment of T,both the peak shear stress and the cohesion decrease,whereas the frictional angle increases.During the compressing and shearing tests,the maximum acoustic emission counts show a decreasing trend when T increases from 25 to 900℃.When T exceeds 573℃,the crystal lattice structure of quartz changes fromα-phase toβ-phase,decreasing the mechanical behavior of granites to a great extent.In addition,the results also indicate that T=500−600℃ is the critical temperature ramge to characterize the influence of temperature on the physical,mechanical and acoustic emission characteristics of granites.展开更多
Two new binary near-azeotropic mixtures named M1 and M2 were developed as the refrigerants of the high-temperature heat pump(HTHP).The experimental research was used to analyze and compare the performance of M1 and M2...Two new binary near-azeotropic mixtures named M1 and M2 were developed as the refrigerants of the high-temperature heat pump(HTHP).The experimental research was used to analyze and compare the performance of M1 and M2-based in the HTHP in different running conditions.The results demonstrated the feasibility and reliability of M1 and M2 as new high-temperature refrigerants.Additionally,the exploration and analyses of the support vector machine(SVM)and back propagation(BP)neural network models were made to find a practical way to predict the performance of HTHP system.The results showed that SVM-Linear,SVM-RBF and BP models shared the similar ability to predict the heat capacity and power input with high accuracy.SVM-RBF demonstrated better stability for coefficient of performance prediction.Finally,the proposed SVM model was used to assess the potential of the M1 and M2.The results indicated that the HTHP system using M1 could produce heat at the temperature of 130°C with good performance.展开更多
To understand the response characteristics of soybean seedling resistance systems to high-temperature stress,the spring soybean varieties HN44 and HN65 were selected in this study as the experimental materials,as they...To understand the response characteristics of soybean seedling resistance systems to high-temperature stress,the spring soybean varieties HN44 and HN65 were selected in this study as the experimental materials,as they had substantial differences in stress resistance.Soybean physiological status was studied under high-temperature stress.Sand culture was used in the experiment,and soybeans at the seedling stage were treated with high-temperature stress.The results showed that the activity of antioxidases and osmotic regulatory substance contents in soybean increased under high-temperature treatment for a certain period of time,the activity of antioxidases and osmotic regulatory substance contents decreased after continuous treatment,and high temperatures continuously increased malondialdehyde contents in the two varieties.At high temperatures,the antioxidant activity and osmotic regulator contents of HN44 were higher than those of HN65,and the malondialdehyde contents of HN44 were higher than those of HN65.The above results showed that HN44 soybeans exhibited significantly higher resistance to high-temperature stress than HN65 variety.展开更多
Semiconductors and related fields today hold vast application prospects.The semiconductor wafer fabrication process involves steps such as substrate preparation and epitaxy,which occur in high-temperature corrosive en...Semiconductors and related fields today hold vast application prospects.The semiconductor wafer fabrication process involves steps such as substrate preparation and epitaxy,which occur in high-temperature corrosive environments.Consequently,components like crucibles,susceptors and wafer carriers require carbon-based materials such as graphite and carbon-carbon composites.However,traditional carbon materials underperform in these extreme conditions,failing to effectively address the challenges.This leads to issues including product contamination and shortened equipment lifespan.Therefore,effective protection of carbon materials is crucial.This paper reviews current research status on the preparation methods and properties of corrosion-resistant coatings within relevant domestic and international fields.Preparation methods include various techniques such as physical vapor deposition(PVD),chemical vapor deposition(CVD)and the sol-gel method.Furthermore,it offers perspectives on future research directions for corrosion-resistant coated components in semiconductor equipment.These include exploring novel coating materials,improving coating preparation processes,enhancing coating corrosion resistance,as well as further investigating the interfacial interactions between coatings and carbon substrates to achieve better adhesion and compatibility.展开更多
High-temperature piezoelectric vibration sensors are the preferred choice for structural health monitoring in harsh environments such as high temperatures and complex vibrations.Bismuth layer-structured CaBi_(4)Ti_(4)...High-temperature piezoelectric vibration sensors are the preferred choice for structural health monitoring in harsh environments such as high temperatures and complex vibrations.Bismuth layer-structured CaBi_(4)Ti_(4)O_(15)(CBT)high-temperature piezoelectric ceramics,with high Curie temperature(TC),are the key components for piezoelectric vibration sensors operating at temperatures exceeding 500℃.However,their low piezoelectric coefficient(d_(33))greatly limits their high-temperature applications.In this work,a novel Bi^(3+)self-doping strategy was employed to enhance the piezoelectric performance of CBT ceramics.The enhancement is attributed to an increase in the number of grain boundaries,providing more sites for space charge accumulation and promoting formation of space charge polarization.Furthermore,given that space charge polarization predominantly occurs at low frequencies,dielectric temperature spectra at different frequencies were used to elucidate the mechanism by which space charge polarization enhances piezoelectric properties of CBT ceramics.Excellent overall performance was achieved for the CBT-based high-temperature piezoelectric ceramics.Among them,TC reached 778℃,d_(33) increased by more than 30%,reaching 20.1 pC/N,and the electrical resistivity improved by one order of magnitude(reaching 6.33×10^(6)Ω·cm at 500℃).These advancements provide a key functional material with excellent performance for practical applications of piezoelectric vibration sensors at 500℃and above.展开更多
文摘This study investigated the physicochemical properties,enzyme activities,volatile flavor components,microbial communities,and sensory evaluation of high-temperature Daqu(HTD)during the maturation process,and a standard system was established for comprehensive quality evaluation of HTD.There were obvious changes in the physicochemical properties,enzyme activities,and volatile flavor components at different storage periods,which affected the sensory evaluation of HTD to a certain extent.The results of high-throughput sequencing revealed significant microbial diversity,and showed that the bacterial community changed significantly more than did the fungal community.During the storage process,the dominant bacterial genera were Kroppenstedtia and Thermoascus.The correlation between dominant microorganisms and quality indicators highlighted their role in HTD quality.Lactococcus,Candida,Pichia,Paecilomyces,and protease activity played a crucial role in the formation of isovaleraldehyde.Acidic protease activity had the greatest impact on the microbial community.Moisture promoted isobutyric acid generation.Furthermore,the comprehensive quality evaluation standard system was established by the entropy weight method combined with multi-factor fuzzy mathematics.Consequently,this study provides innovative insights for comprehensive quality evaluation of HTD during storage and establishes a groundwork for scientific and rational storage of HTD and quality control of sauce-flavor Baijiu.
基金Projects(51979272,BZ2020066)supported by the National Natural Science Foundation of ChinaProjet supported by the Department of Science and Technology of Jiangsu Province,China。
文摘To investigate the influence of temperature on the physical,mechanical and acoustic emission characteristics of granites,uniaxial compression test,variable-angle shear test,acoustic emission signal monitoring and the measurement of physical parameters including mass,size and P-wave velocity were carried out on granite samples treated at temperatures T ranging from 25 to 900℃.The results show that the density and P-wave velocity decrease gradually with increasing T.As the temperature increases,the peak compressive stress decreases while the peak strain increases,due to the fact that a high temperature induces the escaping of waters within granites,the expanding of mineral grains and the generations of fractures.With the increment of T,both the peak shear stress and the cohesion decrease,whereas the frictional angle increases.During the compressing and shearing tests,the maximum acoustic emission counts show a decreasing trend when T increases from 25 to 900℃.When T exceeds 573℃,the crystal lattice structure of quartz changes fromα-phase toβ-phase,decreasing the mechanical behavior of granites to a great extent.In addition,the results also indicate that T=500−600℃ is the critical temperature ramge to characterize the influence of temperature on the physical,mechanical and acoustic emission characteristics of granites.
基金Project (2015CB251403) supported by the National Key Basic Research Program of China(973)
文摘Two new binary near-azeotropic mixtures named M1 and M2 were developed as the refrigerants of the high-temperature heat pump(HTHP).The experimental research was used to analyze and compare the performance of M1 and M2-based in the HTHP in different running conditions.The results demonstrated the feasibility and reliability of M1 and M2 as new high-temperature refrigerants.Additionally,the exploration and analyses of the support vector machine(SVM)and back propagation(BP)neural network models were made to find a practical way to predict the performance of HTHP system.The results showed that SVM-Linear,SVM-RBF and BP models shared the similar ability to predict the heat capacity and power input with high accuracy.SVM-RBF demonstrated better stability for coefficient of performance prediction.Finally,the proposed SVM model was used to assess the potential of the M1 and M2.The results indicated that the HTHP system using M1 could produce heat at the temperature of 130°C with good performance.
基金Supported by the National Key Research and Development Program(2018YFD1000903)。
文摘To understand the response characteristics of soybean seedling resistance systems to high-temperature stress,the spring soybean varieties HN44 and HN65 were selected in this study as the experimental materials,as they had substantial differences in stress resistance.Soybean physiological status was studied under high-temperature stress.Sand culture was used in the experiment,and soybeans at the seedling stage were treated with high-temperature stress.The results showed that the activity of antioxidases and osmotic regulatory substance contents in soybean increased under high-temperature treatment for a certain period of time,the activity of antioxidases and osmotic regulatory substance contents decreased after continuous treatment,and high temperatures continuously increased malondialdehyde contents in the two varieties.At high temperatures,the antioxidant activity and osmotic regulator contents of HN44 were higher than those of HN65,and the malondialdehyde contents of HN44 were higher than those of HN65.The above results showed that HN44 soybeans exhibited significantly higher resistance to high-temperature stress than HN65 variety.
基金National Natural Science Foundation of China(12002196,12102140)。
文摘Semiconductors and related fields today hold vast application prospects.The semiconductor wafer fabrication process involves steps such as substrate preparation and epitaxy,which occur in high-temperature corrosive environments.Consequently,components like crucibles,susceptors and wafer carriers require carbon-based materials such as graphite and carbon-carbon composites.However,traditional carbon materials underperform in these extreme conditions,failing to effectively address the challenges.This leads to issues including product contamination and shortened equipment lifespan.Therefore,effective protection of carbon materials is crucial.This paper reviews current research status on the preparation methods and properties of corrosion-resistant coatings within relevant domestic and international fields.Preparation methods include various techniques such as physical vapor deposition(PVD),chemical vapor deposition(CVD)and the sol-gel method.Furthermore,it offers perspectives on future research directions for corrosion-resistant coated components in semiconductor equipment.These include exploring novel coating materials,improving coating preparation processes,enhancing coating corrosion resistance,as well as further investigating the interfacial interactions between coatings and carbon substrates to achieve better adhesion and compatibility.
基金National Natural Science Foundation of China (51932010)。
文摘High-temperature piezoelectric vibration sensors are the preferred choice for structural health monitoring in harsh environments such as high temperatures and complex vibrations.Bismuth layer-structured CaBi_(4)Ti_(4)O_(15)(CBT)high-temperature piezoelectric ceramics,with high Curie temperature(TC),are the key components for piezoelectric vibration sensors operating at temperatures exceeding 500℃.However,their low piezoelectric coefficient(d_(33))greatly limits their high-temperature applications.In this work,a novel Bi^(3+)self-doping strategy was employed to enhance the piezoelectric performance of CBT ceramics.The enhancement is attributed to an increase in the number of grain boundaries,providing more sites for space charge accumulation and promoting formation of space charge polarization.Furthermore,given that space charge polarization predominantly occurs at low frequencies,dielectric temperature spectra at different frequencies were used to elucidate the mechanism by which space charge polarization enhances piezoelectric properties of CBT ceramics.Excellent overall performance was achieved for the CBT-based high-temperature piezoelectric ceramics.Among them,TC reached 778℃,d_(33) increased by more than 30%,reaching 20.1 pC/N,and the electrical resistivity improved by one order of magnitude(reaching 6.33×10^(6)Ω·cm at 500℃).These advancements provide a key functional material with excellent performance for practical applications of piezoelectric vibration sensors at 500℃and above.
