Edible zein-based films containing lysozyme(LY) and ascorbic acid(AA) were developed in the presence of polyethylene glycol 400(PEG 400), the combined effects of LY and AA on the microstructure, mechanical properties ...Edible zein-based films containing lysozyme(LY) and ascorbic acid(AA) were developed in the presence of polyethylene glycol 400(PEG 400), the combined effects of LY and AA on the microstructure, mechanical properties and release properties of developed zein films were investigated in detail. The results of microstructure characterization indicated that zein-based films became compact and smooth, and LY aggregates were well distributed in the zein matrix because of the simultaneous addition of LY and AA. The results of mechanical tests showed that because of the synergistic effects of LY and AA on zein film, elongation at break of zein-based film could be up to 138%, which was 34.5 times higher than that of zein control film. LY release tests showed that when the concentration of AA was less than 3.1 mg·cm^(-2), the release rate of LY significantly decreased by 33.7%, and the total release increased by 80.6%. While the release profiles of AA showed that the release rate and total release of AA from the films containing LY increased by approximately 68.9% and 61.7% than the films without LY. Good antioxidant and sustained antimicrobial activities were found for the developed zein films.展开更多
Heterogeneous information network(HIN)has recently been widely adopted to describe complex graph structure in recommendation systems,proving its effectiveness in modeling complex graph data.Although existing HIN-based...Heterogeneous information network(HIN)has recently been widely adopted to describe complex graph structure in recommendation systems,proving its effectiveness in modeling complex graph data.Although existing HIN-based recommendation studies have achieved great success by performing message propagation between connected nodes on the defined metapaths,they have the following major limitations.Existing works mainly convert heterogeneous graphs into homogeneous graphs via defining metapaths,which are not expressive enough to capture more complicated dependency relationships involved on the metapath.Besides,the heterogeneous information is more likely to be provided by item attributes while social relations between users are not adequately considered.To tackle these limitations,we propose a novel social recommendation model MPISR,which models MetaPath Interaction for Social Recommendation on heterogeneous information network.Specifically,our model first learns the initial node representation through a pretraining module,and then identifies potential social friends and item relations based on their similarity to construct a unified HIN.We then develop the two-way encoder module with similarity encoder and instance encoder to capture the similarity collaborative signals and relational dependency on different metapaths.Extensive experiments on five real datasets demonstrate the effectiveness of our method.展开更多
Disodium 5′-ribonucleotide,which is composed of disodium 5′-inosine(IMP)and disodium 5′-guanosine(GMP),is an important food additive.The lack of kinetic studies of it causes a lack of clarity in understanding the c...Disodium 5′-ribonucleotide,which is composed of disodium 5′-inosine(IMP)and disodium 5′-guanosine(GMP),is an important food additive.The lack of kinetic studies of it causes a lack of clarity in understanding the complicated multi-solute crystallization of IMP+GMP in ethanol-water.In this work,process analytical technology tools were used to obtain the thermodynamics and kinetic data from the experiments,the kinetic parameters of anti-solvent and cooling crystallization were investigated.The crystal form of IMP+GMP mixed crystal was determined,which was consistent with the IMP whether crystallized from pure water or ethanol-water.The effects of different anti-solvent addition rates and cooling rates on the metastable zone widths were studied,and the opposite effect on metastable zone width was found.The modified exponential empirical function was developed to correlate nucleation and growth kinetic equations under different conditions.The kinetic data were well fitted with adjusted correlation coefficient(adj-R^(2)>0.7),which is sufficient to provide a valid reference for process design and control.展开更多
Aims Grassland is the most widely distributed vegetation type on the Xizang Plateau.Accurate remote sensing estimation of the grass-land aboveground biomass(AGB)in this region is influenced by the types of vegetation ...Aims Grassland is the most widely distributed vegetation type on the Xizang Plateau.Accurate remote sensing estimation of the grass-land aboveground biomass(AGB)in this region is influenced by the types of vegetation indexes(VIs)used,the grain size(resolution)of the remote sensing data and the targeted ecosystem features.This study attempts to answer the following questions:(i)Which VI can most accurately reflect the grassland AGB distribution on the Xizang Plateau?(ii)How does the grain size of remote sensing imagery affect AGB reflection?(iii)What is the spatial distribution pattern of the grassland AGB on the plateau and its relationship with the climate?Methods We investigated 90 sample sites and measured site-specific AGBs using the harvest method for three grassland types(alpine meadow,alpine steppe and desert steppe).For each sample site,four VIs,namely,Normalized Difference VI(NDVI),Enhanced VI,Normalized Difference Water Index(NDWI)and Modified Soil-Adjusted VI(MSAVI)were extracted from the Moderate Resolution Imaging Spectroradiometer(MODIS)products with grain sizes of 250 m and 1 km.Linear regression models were employed to iden-tify the best estimator of the AGB for the entire grassland and the three individual grassland types.Paired Wilcoxon tests were applied to assess the grain size effect on the AGB estimation.General linear models were used to quantify the relationships between the spatial distribution of the grassland AGB and climatic factors.Important Findings The results showed that the best estimator for the entire grass-land AGB on the Xizang Plateau was MSAVI at a 250 m grain size(MSAVI_(250 m)).For each individual grassland type,the best estimator was MSAVI at a grain size of 250 m for alpine meadow,NDWI at a grain size of 1 km for alpine steppe and NDVI at a grain size of 1 km for desert steppe.The explanation ability of each VI for the grassland AGB did not significantly differ for the two grain sizes.Based on the best fit model(AGB=−10.80+139.13 MSAVI_(250 m)),the spatial pattern of the grassland AGB on the plateau was characterized.The AGB varied from 1 to 136 g m^(−2).Approximately 59%of total spatial variation in the AGB for the entire grassland was explained by the combination of the mean annual precipitation(MAP)and mean annual temperature.The explanatory power of MAP was weaker for each individual grassland type than that for the entire grassland.This study illustrated the high efficiency of the VIs derived from MODIS data in the grassland AGB estimation on the Xizang Plateau due to the vegetation homogeneity within a 1×1 km pixel in this region.Furthermore,MAP is a primary driver on the spatial variation of AGB at a regional scale.展开更多
Embedded aluminum-steel composite sheets used in heat exchanger were produced by cold roll bonding(CRB). The influences of annealing temperature and annealing time on the microstructure and the bonding strength of the...Embedded aluminum-steel composite sheets used in heat exchanger were produced by cold roll bonding(CRB). The influences of annealing temperature and annealing time on the microstructure and the bonding strength of the composite sheet were investigated. The recrystallization of the steel layer began at 525℃ and finished at 600℃. With the increase of the annealing temperature, the peel strength of the composite sheet whose original steel sheet surface was treated by scratch brush initially increased and then decreased, which was resulted from the competition of the mechanical locking and metallurgical bonding. After annealing, the cracks which formed between the broken work-hardened steel surface layer and its matrix during cold roll bonding remained. The composite sheet produced by CRB with the steel surface treatment of flap disc had less interfacial defects, higher bonding quality, higher diffusion rate of Al and Fe atoms at the interface and larger metallurgical bonding extent than the composite sheet produced by CRB with the steel surface treatment of scratch brush under the same conditions of annealing,which was helpful to shorten annealing time, reduce energy consumption and improve production efficiency.展开更多
Cu-0.57Cr-0.01Ca and Cu-0.58Cr-0.01Sr(wt.%)alloys were fabricated and processed by thermo-mechanical treatment.Their mechanical and electrical properties and microstructure were investigated in detail and compared wit...Cu-0.57Cr-0.01Ca and Cu-0.58Cr-0.01Sr(wt.%)alloys were fabricated and processed by thermo-mechanical treatment.Their mechanical and electrical properties and microstructure were investigated in detail and compared with those of a Cu-0.57Cr(wt.%)alloy.The results showed that the softening resistance of the Cu-Cr alloy was significantly improved by the additions of Ca and Sr elements.Compared with the Cu-Cr alloy,the deformation microstructure of the Cu-Cr-Ca and Cu-Cr-Sr alloys was more difficult to recrystallize at elevated temperatures,and the Cr precipitates in the Cu-Cr-Ca and Cu-Cr-Sr alloys were smaller in size and had an FCC structure at any given aging state.The high strengths of the Cu-Cr-Ca and Cu-Cr-Sr alloys were mainly attributed to the dislocation strengthening provided by high-density dislocations and the precipitate strengthening provided by fine Cr precipitates.First-principles calculation showed that the segregations of Ca and Sr atoms at interface between Cr precipitates and copper matrix were favorable in energetics.This segregation effectively hindered the growth of Cr precipitates and significantly enhanced the pinning effect on the motion of dislocations and subgrain boundaries,eventually leading to the improvement in the softening resistance of the Cu-Cr alloy.展开更多
Heat treatment is an effective method to improve the intergranular corrosion resistance of the sensitized Al–Mg alloy due to dissolution of the grain boundary precipitates above the solvus temperature ofβ-phase.The ...Heat treatment is an effective method to improve the intergranular corrosion resistance of the sensitized Al–Mg alloy due to dissolution of the grain boundary precipitates above the solvus temperature ofβ-phase.The grain boundary precipitates will grow and coarsening below the solvus temperature.In this study,the in-situ intergranular corrosion performance regeneration of the sensitized Al–Mg alloy can be realized by low-density electro-pulsing treatment below the solvus temperature ofβ-phase.Our findings show that the dissolution of grain boundary precipitates by electro-pulsing treatment is accelerated at relatively low temperature in comparison to traditional heat treatment.The athermal effect produced by the interaction between atoms and electrons on the dissolution of grain boundary precipitates is the main reason for the improved corrosion resistance below the solvus temperature ofβ-phase.展开更多
To improve the physicochemical properties of astaxanthin, it was encapsulated in poly (1-lactic acid)(PLLA) using a supercritical anti-solvent (SAS) process with dichloromethane/acetone mixture as the solvent, and sup...To improve the physicochemical properties of astaxanthin, it was encapsulated in poly (1-lactic acid)(PLLA) using a supercritical anti-solvent (SAS) process with dichloromethane/acetone mixture as the solvent, and supercritical CO2 as the anti-solvent. The effects of altering five SAS operating cond让ions, solvent ratio, temperature, pressure, concentration of carrier, and flow rate, on the microstructure of particles were investigated using an orthogonal experimental design. Under the optimal conditions, astaxanthin/PLLA particles were produced with an encapsulation efficiency of 91.5% and a mean particle size of 954.6 nm. SEM images showed that most astaxanthin/PLLA particles were uniform microspheres. FT-IR spectra showed that the chemical structure of astaxanthin was unchanged by the SAS process. The results of chromatic difference, X-ray diffraction, thermogravimetric, and differential scanning calorimetry analyses showed that astaxanthin had been encapsulated in the PLLA matrix in an amorphous state. Overall, astaxanthin/PLLA microspheres greatly enhanced the stability of astaxanthin during storage, and the levels of residual solvents were far lower than the ICH lim让s. This means that astaxanthin/PLLA microspheres prepared using SAS show great potential for use in many food, cosmetic, and pharmaceutical formulations.展开更多
基金Supported by the National Natural Science Foundation of China(21476086)Guangdong Natural Science Foundation(2014A030312007)
文摘Edible zein-based films containing lysozyme(LY) and ascorbic acid(AA) were developed in the presence of polyethylene glycol 400(PEG 400), the combined effects of LY and AA on the microstructure, mechanical properties and release properties of developed zein films were investigated in detail. The results of microstructure characterization indicated that zein-based films became compact and smooth, and LY aggregates were well distributed in the zein matrix because of the simultaneous addition of LY and AA. The results of mechanical tests showed that because of the synergistic effects of LY and AA on zein film, elongation at break of zein-based film could be up to 138%, which was 34.5 times higher than that of zein control film. LY release tests showed that when the concentration of AA was less than 3.1 mg·cm^(-2), the release rate of LY significantly decreased by 33.7%, and the total release increased by 80.6%. While the release profiles of AA showed that the release rate and total release of AA from the films containing LY increased by approximately 68.9% and 61.7% than the films without LY. Good antioxidant and sustained antimicrobial activities were found for the developed zein films.
基金supported by the National Natural Science Foundation of China(Grant Nos.61762078,62276073,61966009 and U22A2099)the Industrial Support Project of Gansu Colleges(No.2022CYZC11)+3 种基金the Natural Science Foundation of Gansu Province(21JR7RA114)the Northwest Normal University Young Teachers Research Capacity Promotion Plan(NWNU-LKQN2019-2)the Industrial Support Project of Gansu Colleges(No.2022CYZC11)the Northwest Normal University Post-graduate Research Funding Project(2021KYZZ02107).
文摘Heterogeneous information network(HIN)has recently been widely adopted to describe complex graph structure in recommendation systems,proving its effectiveness in modeling complex graph data.Although existing HIN-based recommendation studies have achieved great success by performing message propagation between connected nodes on the defined metapaths,they have the following major limitations.Existing works mainly convert heterogeneous graphs into homogeneous graphs via defining metapaths,which are not expressive enough to capture more complicated dependency relationships involved on the metapath.Besides,the heterogeneous information is more likely to be provided by item attributes while social relations between users are not adequately considered.To tackle these limitations,we propose a novel social recommendation model MPISR,which models MetaPath Interaction for Social Recommendation on heterogeneous information network.Specifically,our model first learns the initial node representation through a pretraining module,and then identifies potential social friends and item relations based on their similarity to construct a unified HIN.We then develop the two-way encoder module with similarity encoder and instance encoder to capture the similarity collaborative signals and relational dependency on different metapaths.Extensive experiments on five real datasets demonstrate the effectiveness of our method.
基金Financial supports from the National Natural Science Foundation of China (Nos.22178121 and 21908254)are greatly appreciated.
文摘Disodium 5′-ribonucleotide,which is composed of disodium 5′-inosine(IMP)and disodium 5′-guanosine(GMP),is an important food additive.The lack of kinetic studies of it causes a lack of clarity in understanding the complicated multi-solute crystallization of IMP+GMP in ethanol-water.In this work,process analytical technology tools were used to obtain the thermodynamics and kinetic data from the experiments,the kinetic parameters of anti-solvent and cooling crystallization were investigated.The crystal form of IMP+GMP mixed crystal was determined,which was consistent with the IMP whether crystallized from pure water or ethanol-water.The effects of different anti-solvent addition rates and cooling rates on the metastable zone widths were studied,and the opposite effect on metastable zone width was found.The modified exponential empirical function was developed to correlate nucleation and growth kinetic equations under different conditions.The kinetic data were well fitted with adjusted correlation coefficient(adj-R^(2)>0.7),which is sufficient to provide a valid reference for process design and control.
基金National Natural Science Foundation of China(31300356)Chinese National Key Program for Developing Basic Science(2013CB956302)+1 种基金China Postdoctoral Science Foundation(2013M530717)Hundred Talents Program of Chinese Academy of Sciences(Y11S0400P5).
文摘Aims Grassland is the most widely distributed vegetation type on the Xizang Plateau.Accurate remote sensing estimation of the grass-land aboveground biomass(AGB)in this region is influenced by the types of vegetation indexes(VIs)used,the grain size(resolution)of the remote sensing data and the targeted ecosystem features.This study attempts to answer the following questions:(i)Which VI can most accurately reflect the grassland AGB distribution on the Xizang Plateau?(ii)How does the grain size of remote sensing imagery affect AGB reflection?(iii)What is the spatial distribution pattern of the grassland AGB on the plateau and its relationship with the climate?Methods We investigated 90 sample sites and measured site-specific AGBs using the harvest method for three grassland types(alpine meadow,alpine steppe and desert steppe).For each sample site,four VIs,namely,Normalized Difference VI(NDVI),Enhanced VI,Normalized Difference Water Index(NDWI)and Modified Soil-Adjusted VI(MSAVI)were extracted from the Moderate Resolution Imaging Spectroradiometer(MODIS)products with grain sizes of 250 m and 1 km.Linear regression models were employed to iden-tify the best estimator of the AGB for the entire grassland and the three individual grassland types.Paired Wilcoxon tests were applied to assess the grain size effect on the AGB estimation.General linear models were used to quantify the relationships between the spatial distribution of the grassland AGB and climatic factors.Important Findings The results showed that the best estimator for the entire grass-land AGB on the Xizang Plateau was MSAVI at a 250 m grain size(MSAVI_(250 m)).For each individual grassland type,the best estimator was MSAVI at a grain size of 250 m for alpine meadow,NDWI at a grain size of 1 km for alpine steppe and NDVI at a grain size of 1 km for desert steppe.The explanation ability of each VI for the grassland AGB did not significantly differ for the two grain sizes.Based on the best fit model(AGB=−10.80+139.13 MSAVI_(250 m)),the spatial pattern of the grassland AGB on the plateau was characterized.The AGB varied from 1 to 136 g m^(−2).Approximately 59%of total spatial variation in the AGB for the entire grassland was explained by the combination of the mean annual precipitation(MAP)and mean annual temperature.The explanatory power of MAP was weaker for each individual grassland type than that for the entire grassland.This study illustrated the high efficiency of the VIs derived from MODIS data in the grassland AGB estimation on the Xizang Plateau due to the vegetation homogeneity within a 1×1 km pixel in this region.Furthermore,MAP is a primary driver on the spatial variation of AGB at a regional scale.
基金supported by the National High Technology Research and Development Program of China (2013AA031301)the National Natural Science Foundation of China (51104016)the Natural Science Foundation of Jiangsu Province (BK20161151)
文摘Embedded aluminum-steel composite sheets used in heat exchanger were produced by cold roll bonding(CRB). The influences of annealing temperature and annealing time on the microstructure and the bonding strength of the composite sheet were investigated. The recrystallization of the steel layer began at 525℃ and finished at 600℃. With the increase of the annealing temperature, the peel strength of the composite sheet whose original steel sheet surface was treated by scratch brush initially increased and then decreased, which was resulted from the competition of the mechanical locking and metallurgical bonding. After annealing, the cracks which formed between the broken work-hardened steel surface layer and its matrix during cold roll bonding remained. The composite sheet produced by CRB with the steel surface treatment of flap disc had less interfacial defects, higher bonding quality, higher diffusion rate of Al and Fe atoms at the interface and larger metallurgical bonding extent than the composite sheet produced by CRB with the steel surface treatment of scratch brush under the same conditions of annealing,which was helpful to shorten annealing time, reduce energy consumption and improve production efficiency.
基金financially supported by the National MCF Energy R&D Program of China(No.2018YFE0306100)the National Natural Science Foundation of China(No.51974375)+4 种基金the Technology Research Program of Ningbo,China(No.2019B10088)the Key Technologies R&D Program of Yunnan Province(No.202102AB080019-1)the Young People Fund of Jiang Xi Province(No.2018BAB216005)the Fundamental Research Funds for the Central Universities of Central South University(No.2020zzts071)the Postgraduate Scientific Research Innovation Project of Hunan Province(No.CX20200100)。
文摘Cu-0.57Cr-0.01Ca and Cu-0.58Cr-0.01Sr(wt.%)alloys were fabricated and processed by thermo-mechanical treatment.Their mechanical and electrical properties and microstructure were investigated in detail and compared with those of a Cu-0.57Cr(wt.%)alloy.The results showed that the softening resistance of the Cu-Cr alloy was significantly improved by the additions of Ca and Sr elements.Compared with the Cu-Cr alloy,the deformation microstructure of the Cu-Cr-Ca and Cu-Cr-Sr alloys was more difficult to recrystallize at elevated temperatures,and the Cr precipitates in the Cu-Cr-Ca and Cu-Cr-Sr alloys were smaller in size and had an FCC structure at any given aging state.The high strengths of the Cu-Cr-Ca and Cu-Cr-Sr alloys were mainly attributed to the dislocation strengthening provided by high-density dislocations and the precipitate strengthening provided by fine Cr precipitates.First-principles calculation showed that the segregations of Ca and Sr atoms at interface between Cr precipitates and copper matrix were favorable in energetics.This segregation effectively hindered the growth of Cr precipitates and significantly enhanced the pinning effect on the motion of dislocations and subgrain boundaries,eventually leading to the improvement in the softening resistance of the Cu-Cr alloy.
基金financially supported by the National Natural Science Foundation of China(Nos.51601011,51571013 and 51971019)the Beijing Laboratory of Metallic Materials and Processing for Modern Transportation,China。
文摘Heat treatment is an effective method to improve the intergranular corrosion resistance of the sensitized Al–Mg alloy due to dissolution of the grain boundary precipitates above the solvus temperature ofβ-phase.The grain boundary precipitates will grow and coarsening below the solvus temperature.In this study,the in-situ intergranular corrosion performance regeneration of the sensitized Al–Mg alloy can be realized by low-density electro-pulsing treatment below the solvus temperature ofβ-phase.Our findings show that the dissolution of grain boundary precipitates by electro-pulsing treatment is accelerated at relatively low temperature in comparison to traditional heat treatment.The athermal effect produced by the interaction between atoms and electrons on the dissolution of grain boundary precipitates is the main reason for the improved corrosion resistance below the solvus temperature ofβ-phase.
基金Financial support from the National Natural Science Foundation of China (21476086,21776102)China Postdoctoral Science Foundation (No. 2017M612663) is greatly appreciated.
文摘To improve the physicochemical properties of astaxanthin, it was encapsulated in poly (1-lactic acid)(PLLA) using a supercritical anti-solvent (SAS) process with dichloromethane/acetone mixture as the solvent, and supercritical CO2 as the anti-solvent. The effects of altering five SAS operating cond让ions, solvent ratio, temperature, pressure, concentration of carrier, and flow rate, on the microstructure of particles were investigated using an orthogonal experimental design. Under the optimal conditions, astaxanthin/PLLA particles were produced with an encapsulation efficiency of 91.5% and a mean particle size of 954.6 nm. SEM images showed that most astaxanthin/PLLA particles were uniform microspheres. FT-IR spectra showed that the chemical structure of astaxanthin was unchanged by the SAS process. The results of chromatic difference, X-ray diffraction, thermogravimetric, and differential scanning calorimetry analyses showed that astaxanthin had been encapsulated in the PLLA matrix in an amorphous state. Overall, astaxanthin/PLLA microspheres greatly enhanced the stability of astaxanthin during storage, and the levels of residual solvents were far lower than the ICH lim让s. This means that astaxanthin/PLLA microspheres prepared using SAS show great potential for use in many food, cosmetic, and pharmaceutical formulations.
