[Objectives]This study was conducted to explore the dynamic changes of volatile flavor compounds in prepared pork during storage at different low-temperature conditions.[Methods]Prepared pork was stored at 4,-4 and-18...[Objectives]This study was conducted to explore the dynamic changes of volatile flavor compounds in prepared pork during storage at different low-temperature conditions.[Methods]Prepared pork was stored at 4,-4 and-18℃.The volatile flavor compounds of prepared pork were determined by solid-phase microextraction-gas chromatography-mass spectrometry(SPME-GC-MS)at days 0,7,14,21 and 28,and relative odor activity value(OAV),principal component analysis(PCA)and cluster analysis(CA)were combined to analyze changes in volatile flavor compounds of prepared pork during storage.[Results]The total number of volatile flavor compounds gradually decreased with the prolongation of the storage period,and OAV analysis identified 22 key flavor compounds(OAV≥1).The results of PCA and CA showed that 2-methyl-1-butanol,1-octen-3-ol,linalool,cineole,hexanal and nonanal were the main key flavor components,and the degree of flavor degradation was low under both superchilling and freezing conditions.After 28 days of storage,the alcohol content in the chilling group was significantly higher than other two groups,and the overall content of volatile flavor compounds was also significantly higher than other two groups,indicating that the-4℃chilling storage was more favorable for maintaining the overall flavor of prepared pork.[Conclusions]This study provides a theoretical basis for finding a better storage method for prepared meat products.展开更多
Exploiting high-performance yet low-cost hard carbon anodes is crucial to advancing the state-of-the-art sodium-ion batteries.However,the achievement of superior initial Coulombic efficiency(ICE)and high Na-storage ca...Exploiting high-performance yet low-cost hard carbon anodes is crucial to advancing the state-of-the-art sodium-ion batteries.However,the achievement of superior initial Coulombic efficiency(ICE)and high Na-storage capacity via low-temperature carbonization remains challenging due to the presence of tremendous defects with few closed pores.Here,a facile hybrid carbon framework design is proposed from the polystyrene precursor bearing distinct molecular bridges at a low pyrolysis temperature of 800℃ via in situ fusion and embedding strategy.This is realized by integrating triazine-and carbonylcrosslinked polystyrene nanospheres during carbonization.The triazine crosslinking allows in situ fusion of spheres into layered carbon with low defects and abundant closed pores,which serves as a matrix for embedding the well-retained carbon spheres with nanopores/defects derived from carbonyl crosslinking.Therefore,the hybrid hard carbon with intimate interface showcases synergistic Na ions storage behavior,showing an ICE of 70.2%,a high capacity of 279.3 mAh g^(-1),and long-term 500 cycles,superior to carbons from the respective precursor and other reported carbons fabricated under the low carbonization temperature.The present protocol opens new avenues toward low-cost hard carbon anode materials for high-performance sodiumion batteries.展开更多
Although it is recognized that the post-harvest system is most responsible for the loss of soybean quality,the real impact of this loss is still unknown.Brazilian regulation allows 15%and 30%of broken soybean for grou...Although it is recognized that the post-harvest system is most responsible for the loss of soybean quality,the real impact of this loss is still unknown.Brazilian regulation allows 15%and 30%of broken soybean for group I and group II(quality groups),respectively.However,the industry is not informed about the loss in the quality parameters of soybeans and its impacts during long-term storage.Therefore,the objective was to evaluate the effect of the breakage kernel percentage of soybean stored for 12 months.Content of 15% of breakage kernels did not affect soybean quality.However,content of 30% of breakage kernels affected significantly soybean quality,which was evidenced by the increase of up to 75% in moldy soybeans,72% in acidity,50% in leached solids,27% in electrical conductivity,and the decrease of up to 12% in soluble protein,6.4% in germination and 3.5% in thousand kernel weight after 8 months of storage.Although the legislation establishes a percentage limit,it is recommended to store soybeans with up to 15% breakage kernels.On the contrary,values higher than that can cause a significant reduction in soybean quality,resulting in commercial losses.展开更多
Rare earth compositions, La, Ce and Pr in Mm(NiCoMnAl)(5) hydrogen storage alloy, were arranged by uniform design method. The discharge performances and kinetics parameters including capacity, exchange current density...Rare earth compositions, La, Ce and Pr in Mm(NiCoMnAl)(5) hydrogen storage alloy, were arranged by uniform design method. The discharge performances and kinetics parameters including capacity, exchange current density, symmetry factor and hydrogen diffusion coefficient of the alloy at -40degreesC, were tested in standard tri-electrode cell. And linear regression method was used to analyze the effect of rare earth compositions on the performances of hydrogen storage alloys. The results show that the capacities of the alloys are positively correlative to the square of Ce content at -40degreesC and under both 0.4 and 0.2C rate. The kinetics parameters and hydrogen diffusion coefficient indicate that the low-temperature performances of the alloys are mainly controlled by hydrogen diffusion process, and the surface electrochemical reaction affects the low-temperature performances to a certain extent. The low-temperature discharge capacities of the battery were also tested. The results show excellent low-temperature performances. The battery delivers 69.6% of its room-temperature capacity at -40degreesC and 0.2C rate, 77.7% at -40degreesC and 0.4C rate, 59.1% at -45degreesC and 0.2C rate.展开更多
As lithium(Li)-ion batteries expand their applications,operating over a wide temperature range becomes increasingly important.However,the lowtemperature performance of conventional graphite anodes is severely hampered...As lithium(Li)-ion batteries expand their applications,operating over a wide temperature range becomes increasingly important.However,the lowtemperature performance of conventional graphite anodes is severely hampered by the poor diffusion kinetics of Li ions(Li^(+)).Here,zinc oxide(ZnO) nanoparticles are incorporated into the expanded graphite to improve Li^(+)diffusion kinetics,resulting in a significant improvement in lowtemperature performance.The ZnO-embedded expanded graphite anodes are investigated with different amounts of ZnO to establish the structurecharge storage mechanism-performance relationship with a focus on lowtemperature applications.Electrochemical analysis reveals that the ZnOembedded expanded graphite anode with nano-sized ZnO maintains a large portion of the diffusion-controlled charge storage mechanism at an ultra-low temperature of-50℃ Due to this significantly enhanced Li^(+)diffusion rate,a full cell with the ZnO-embedded expanded graphite anode and a LiNi_(0.88)Co_(0.09)Al_(0.03)O_(2)cathode delivers high capacities of 176 mAh g^(-1)at20℃ and 86 mAh g^(-1)at-50℃ at a high rate of 1 C.The outstanding low-temperature performance of the composite anode by improving the Li^(+)diffusion kinetics provides important scientific insights into the fundamental design principles of anodes for low-temperature Li-ion battery operation.展开更多
Grain storage security is big issue related to national economy and the people＇s livelihood, as well as one of the most important strategic requirements in China. Under the background of grain supply-side structural ...Grain storage security is big issue related to national economy and the people＇s livelihood, as well as one of the most important strategic requirements in China. Under the background of grain supply-side structural reform, this paper analyzed the grain storage security countermeasures under the new normal conditions with ＂grain storage technology＂, one of the national grain security strategies of China during the 13th Five-year Plan, as the guiding ideology, from the perspectives of scientific technologies, policy supports, government supports and talent construction, so as to provide supports for the storage enterprises with vulnerable technological links. In addition, the food security issues discussed in this paper could be a helping hand in improving people＇s living quality, enhancing grain storage ecological quality, promoting grain green storage quality security, and be of important and profound strategic significance to enhance the macro-control capability of the government, maintain social stability and people＇s health.展开更多
In China, the quantity of farmer＇s grain storage covers about 40% of the total grain yield every year. While, the losses of farms＇ grain storage are up to 8%, which is due to the lack of grain storage facility and t...In China, the quantity of farmer＇s grain storage covers about 40% of the total grain yield every year. While, the losses of farms＇ grain storage are up to 8%, which is due to the lack of grain storage facility and technology. The losses of farmer＇s grain storage could reach nearly 20 million tons every year. In this paper, the current situation and development of grain storage technology and facility for Chinese farmers were presented. And a series of policy and research work for reducing the losses of farms＇ grain storage was introduced. The large scale farmers are now developing quickly in China, the new storage warehouse and mechanized facility should be developed adaptively. So, the new storage technology and policy to meet the need of large scale farmers were also introduced in this paper.展开更多
Post-harvest storage losses (PHLs) remain significant in Sub-Saharan Africa (SSA) due to several factors mainly insect pests and molds. Hermetic storage technologies (HSTs) are being promoted to address these storage ...Post-harvest storage losses (PHLs) remain significant in Sub-Saharan Africa (SSA) due to several factors mainly insect pests and molds. Hermetic storage technologies (HSTs) are being promoted to address these storage losses. In Uganda, HSTs were first introduced in 2012. However, its use among farming households remains low today. Data were collected from 306 smallholder farmers from four districts of Northern Uganda using a pre-tested semi-structured questionnaire to understand their knowledge, use, and constraints to the adoption of hermetic storage. A multivariate Logit regression model was used to find the significance of the factors affecting adoption. Results showed low awareness and use of hermetic storage among smallholder farmers. Only 53.3% of the interviewed farmers were aware of the use of hermetic storage for grain storage. The SuperGrain bag was the most known form of hermetic storage (35.3%), followed by the Purdue Improved Crop Storage (PICS) bag (34.9%), metallic silo (15.5%), and plastic silo (14.4%). Hermetic storage use was even lower as only 17.6% of the surveyed farmers were using one or more forms of hermetic storage to store their grains. Insect pest management without chemical insecticides was the main reason (83.1%) for hermetic storage use. About 75.5% of those aware of hermetic storage had received training in the technology. Hermetic storage use in farming households led to improved food availability, household income, and nutrition. Lack of local availability (50.2%), high costs (37.8%), and inadequate knowledge (6.9%) were the main constraints hindering the adoption of hermetic storage in Northern Uganda. The logit regression models showed that only training in hermetic storage significantly (p = 0.002) affected farmers’ decision to adopt hermetic storage. Understanding the factors that constrain the adoption of HSTs could provide policymakers with important information to initiate and design policies and programs aimed at reducing crop storage losses.展开更多
The paper presents the change in grain-size composition of lignite under cyclic freezing-thawing (FTC) and wetting-drying (WDC). The article shows that in the spring and autumn periods the lignites can be subjected to...The paper presents the change in grain-size composition of lignite under cyclic freezing-thawing (FTC) and wetting-drying (WDC). The article shows that in the spring and autumn periods the lignites can be subjected to repeated freezing-thawing and wetting-drying, which determines the possibility of changing their grain-size composition and structure. Experimental studies in laboratory conditions on the influence of cyclic freezing-thawing (FTC) and wetting-drying (WDC) on the quality indicators of lignites have been carried out, their granulometric (fractional) composition has been studied. Freezing-thawing cycle conditions are as follows (FTC): minimum exposure temperature: -20°C;maximum: +5°C;relative humidity: 30%;number of processing cycles: 3. Wetting-drying cycles are as follows (WDC): drying temperatures are +20, +40, +60, +80°C, drying time 90 minutes, the coals are further subjected to rain (soaking) for a period of water saturation to humidity of 30% - 40% and dry again. The number of wetting-drying cycles is 3 times. The tests have revealed the destructive effects of FTC and WDC on the samples of lower metamorphic grade coal, and the cycles of wet-dry lead to the much higher yield of fine sizes (-6+0;-13+0 mm) than the cycles of freeze-thaw. Furthermore, it is found that the increase in the yield of fines depends on the heating temperature: coal disintegration proceeds more intensively at a higher temperature of drying.展开更多
The amount of low-temperature heat generated in industrial processes is high,but recycling is limited due to low grade and low recycling efficiency,which is one of the reasons for low energy efficiency.It implies that...The amount of low-temperature heat generated in industrial processes is high,but recycling is limited due to low grade and low recycling efficiency,which is one of the reasons for low energy efficiency.It implies that there is a great potential for low-temperature heat recovery and utilization.This article provided a detailed review of recent advances in the development of low-temperature thermal upgrades,power generation,refrigeration,and thermal energy storage.The detailed description will be given from the aspects of system structure improvement,work medium improvement,and thermodynamic and economic performance evaluation.It also pointed out the development bottlenecks and future development trends of various technologies.The low-temperature heat combined utilization technology can recover waste heat in an all-round and effective manner,and has great development prospects.展开更多
The effect of KOH electrolyte concentration on low-temperature electrochemical properties of LaNi5 alloy electrodes at 233 K was studied. The results indicated that the electrolyte concentration had great influence on...The effect of KOH electrolyte concentration on low-temperature electrochemical properties of LaNi5 alloy electrodes at 233 K was studied. The results indicated that the electrolyte concentration had great influence on discharge capacity and discharge voltage plateau of LaNi5 alloy electrode at 233 K, and the highest discharge capacity and discharge voltage plateau were both obtained at 6 mol/L KOH. When the KOH electrolyte concentration changed from 5 to 9 mol/L at 233 K, the high rate discharge ability （HRD） had the same change tendency as the diffusion coefficient, but the exchange current density did not change significantly, which implied that hydrogen diffusion was the control step at low temperature 233 K for discharge process of LaNi5 alloy electrode.展开更多
A dominant intrinsic luminescence band, which is due to the surface potential barriers of crystalline grains, and an edge doublet, which arises as an LO-phonon repetition of the e-h band, has been revealed in the low-...A dominant intrinsic luminescence band, which is due to the surface potential barriers of crystalline grains, and an edge doublet, which arises as an LO-phonon repetition of the e-h band, has been revealed in the low-temperature photoluminescence spectra of fine-grained obliquely deposited films. Doping film with In impurity leads to quenching of the doublet band, while further thermal treatment causes activation of the intrinsic band, the half-width and the blue shift of the red edge of which correlates with the maximum value of anomalously high photovoltage generated by the film.展开更多
Nanostructured aluminum recently delivers a variety of new applications of the earth-abundant Al resource due to the unique properties,but its controllable synthesis remains very challenging with harsh conditions and ...Nanostructured aluminum recently delivers a variety of new applications of the earth-abundant Al resource due to the unique properties,but its controllable synthesis remains very challenging with harsh conditions and spontaneously flammable precursors.Herein,a surface group directed method is developed to efficiently achieve low-temperature synthesis and selfassembly of zero-dimensional(0D)Al nanocrystals over one-dimensional(1D)carbon fibers(Al@CFs)through non-flammable AlCl3 reduction at 70°C.Theoretical calculations unveil surface‒OLi groups of carbon fibers exert efficient binding effect to AlCl3,which guides intimate adsorption and in-situ self-assembly of the generated Al nanocrystals.The distinctive 0D-over-1D Al@CFs provides long 1D conductive networks for electron transfer,ultrafine 0D Al nanocrystals for fast lithiation and excellent buffering effect for volume change,thus exhibiting high structure stability and superior lithium storage performance.This work paves the way for mild and controllable synthesis of Al-based nanomaterials for new high-value applications.展开更多
基金Supported by Science and Technology Achievement Transformation Program of Sichuan Province(2023ZHCG0079)Research and Application of Key Techniques for Industrialization of Frozen Prepared Meat Dishes(GCZX22-35)Sichuan Pig Innovation Team of National Agricultural Industry Technology System(scsztd-2024-08-07).
文摘[Objectives]This study was conducted to explore the dynamic changes of volatile flavor compounds in prepared pork during storage at different low-temperature conditions.[Methods]Prepared pork was stored at 4,-4 and-18℃.The volatile flavor compounds of prepared pork were determined by solid-phase microextraction-gas chromatography-mass spectrometry(SPME-GC-MS)at days 0,7,14,21 and 28,and relative odor activity value(OAV),principal component analysis(PCA)and cluster analysis(CA)were combined to analyze changes in volatile flavor compounds of prepared pork during storage.[Results]The total number of volatile flavor compounds gradually decreased with the prolongation of the storage period,and OAV analysis identified 22 key flavor compounds(OAV≥1).The results of PCA and CA showed that 2-methyl-1-butanol,1-octen-3-ol,linalool,cineole,hexanal and nonanal were the main key flavor components,and the degree of flavor degradation was low under both superchilling and freezing conditions.After 28 days of storage,the alcohol content in the chilling group was significantly higher than other two groups,and the overall content of volatile flavor compounds was also significantly higher than other two groups,indicating that the-4℃chilling storage was more favorable for maintaining the overall flavor of prepared pork.[Conclusions]This study provides a theoretical basis for finding a better storage method for prepared meat products.
基金financially supported by the project of the National Natural Science Foundation of China (Grant Nos.51972270,52322203)the Key Research and Development Program of Shaanxi Province (Grant NO.2024GH-ZDXM-21)the Fundamental Research Funds for the Central Universities (Grant Nos.G2022KY0607,23GH0202277).
文摘Exploiting high-performance yet low-cost hard carbon anodes is crucial to advancing the state-of-the-art sodium-ion batteries.However,the achievement of superior initial Coulombic efficiency(ICE)and high Na-storage capacity via low-temperature carbonization remains challenging due to the presence of tremendous defects with few closed pores.Here,a facile hybrid carbon framework design is proposed from the polystyrene precursor bearing distinct molecular bridges at a low pyrolysis temperature of 800℃ via in situ fusion and embedding strategy.This is realized by integrating triazine-and carbonylcrosslinked polystyrene nanospheres during carbonization.The triazine crosslinking allows in situ fusion of spheres into layered carbon with low defects and abundant closed pores,which serves as a matrix for embedding the well-retained carbon spheres with nanopores/defects derived from carbonyl crosslinking.Therefore,the hybrid hard carbon with intimate interface showcases synergistic Na ions storage behavior,showing an ICE of 70.2%,a high capacity of 279.3 mAh g^(-1),and long-term 500 cycles,superior to carbons from the respective precursor and other reported carbons fabricated under the low carbonization temperature.The present protocol opens new avenues toward low-cost hard carbon anode materials for high-performance sodiumion batteries.
基金Coordenacao de Aperfeicoamento de Pessoal de Nível Superior - Brasil (CAPES)Fundacao de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS)+2 种基金Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)financed in part by Coordenacao de Aperfeicoamento de Pessoal de Nível Superior-Brasil(CAPES)-Finance code 001,Fundacao de Amparoa Pesquisa do Estado do Rio Grande do Sul(FAPERGS)-Finances code 17/2551-0000935-5,22/2551-0001051-2,21/2551-0002255-8Conselho Nacional de Desenvolvimento Científico e Tecnologico(CNPq)-Finance codes 205518/2018-4,312603/2018-5.
文摘Although it is recognized that the post-harvest system is most responsible for the loss of soybean quality,the real impact of this loss is still unknown.Brazilian regulation allows 15%and 30%of broken soybean for group I and group II(quality groups),respectively.However,the industry is not informed about the loss in the quality parameters of soybeans and its impacts during long-term storage.Therefore,the objective was to evaluate the effect of the breakage kernel percentage of soybean stored for 12 months.Content of 15% of breakage kernels did not affect soybean quality.However,content of 30% of breakage kernels affected significantly soybean quality,which was evidenced by the increase of up to 75% in moldy soybeans,72% in acidity,50% in leached solids,27% in electrical conductivity,and the decrease of up to 12% in soluble protein,6.4% in germination and 3.5% in thousand kernel weight after 8 months of storage.Although the legislation establishes a percentage limit,it is recommended to store soybeans with up to 15% breakage kernels.On the contrary,values higher than that can cause a significant reduction in soybean quality,resulting in commercial losses.
文摘Rare earth compositions, La, Ce and Pr in Mm(NiCoMnAl)(5) hydrogen storage alloy, were arranged by uniform design method. The discharge performances and kinetics parameters including capacity, exchange current density, symmetry factor and hydrogen diffusion coefficient of the alloy at -40degreesC, were tested in standard tri-electrode cell. And linear regression method was used to analyze the effect of rare earth compositions on the performances of hydrogen storage alloys. The results show that the capacities of the alloys are positively correlative to the square of Ce content at -40degreesC and under both 0.4 and 0.2C rate. The kinetics parameters and hydrogen diffusion coefficient indicate that the low-temperature performances of the alloys are mainly controlled by hydrogen diffusion process, and the surface electrochemical reaction affects the low-temperature performances to a certain extent. The low-temperature discharge capacities of the battery were also tested. The results show excellent low-temperature performances. The battery delivers 69.6% of its room-temperature capacity at -40degreesC and 0.2C rate, 77.7% at -40degreesC and 0.4C rate, 59.1% at -45degreesC and 0.2C rate.
基金supported by an Early Career Faculty Grant from NASA’s Space Technology Research Grants Program (80NSSC18K1509)supported by the Institute for Electronics and Nanotechnology Seed Grant and performed in part at the Georgia Tech Institute for Electronics and Nanotechnology, a member of the National Nanotechnology Coordinated Infrastructure (NNCI), which was supported by the National Science Foundation (ECCS-2025462)
文摘As lithium(Li)-ion batteries expand their applications,operating over a wide temperature range becomes increasingly important.However,the lowtemperature performance of conventional graphite anodes is severely hampered by the poor diffusion kinetics of Li ions(Li^(+)).Here,zinc oxide(ZnO) nanoparticles are incorporated into the expanded graphite to improve Li^(+)diffusion kinetics,resulting in a significant improvement in lowtemperature performance.The ZnO-embedded expanded graphite anodes are investigated with different amounts of ZnO to establish the structurecharge storage mechanism-performance relationship with a focus on lowtemperature applications.Electrochemical analysis reveals that the ZnOembedded expanded graphite anode with nano-sized ZnO maintains a large portion of the diffusion-controlled charge storage mechanism at an ultra-low temperature of-50℃ Due to this significantly enhanced Li^(+)diffusion rate,a full cell with the ZnO-embedded expanded graphite anode and a LiNi_(0.88)Co_(0.09)Al_(0.03)O_(2)cathode delivers high capacities of 176 mAh g^(-1)at20℃ and 86 mAh g^(-1)at-50℃ at a high rate of 1 C.The outstanding low-temperature performance of the composite anode by improving the Li^(+)diffusion kinetics provides important scientific insights into the fundamental design principles of anodes for low-temperature Li-ion battery operation.
基金Supported by the Fund Project for the Scientific Undertakings in Public Interest of Liaoning Province(20170046)the Initiation Project of Economic and Social Development of Liaoning Province(2018lslktyb)the Initiation Project of Economic and Social Development of Shenyang City in 2017(SYSK2017-13-11)~~
文摘Grain storage security is big issue related to national economy and the people＇s livelihood, as well as one of the most important strategic requirements in China. Under the background of grain supply-side structural reform, this paper analyzed the grain storage security countermeasures under the new normal conditions with ＂grain storage technology＂, one of the national grain security strategies of China during the 13th Five-year Plan, as the guiding ideology, from the perspectives of scientific technologies, policy supports, government supports and talent construction, so as to provide supports for the storage enterprises with vulnerable technological links. In addition, the food security issues discussed in this paper could be a helping hand in improving people＇s living quality, enhancing grain storage ecological quality, promoting grain green storage quality security, and be of important and profound strategic significance to enhance the macro-control capability of the government, maintain social stability and people＇s health.
文摘In China, the quantity of farmer＇s grain storage covers about 40% of the total grain yield every year. While, the losses of farms＇ grain storage are up to 8%, which is due to the lack of grain storage facility and technology. The losses of farmer＇s grain storage could reach nearly 20 million tons every year. In this paper, the current situation and development of grain storage technology and facility for Chinese farmers were presented. And a series of policy and research work for reducing the losses of farms＇ grain storage was introduced. The large scale farmers are now developing quickly in China, the new storage warehouse and mechanized facility should be developed adaptively. So, the new storage technology and policy to meet the need of large scale farmers were also introduced in this paper.
文摘Post-harvest storage losses (PHLs) remain significant in Sub-Saharan Africa (SSA) due to several factors mainly insect pests and molds. Hermetic storage technologies (HSTs) are being promoted to address these storage losses. In Uganda, HSTs were first introduced in 2012. However, its use among farming households remains low today. Data were collected from 306 smallholder farmers from four districts of Northern Uganda using a pre-tested semi-structured questionnaire to understand their knowledge, use, and constraints to the adoption of hermetic storage. A multivariate Logit regression model was used to find the significance of the factors affecting adoption. Results showed low awareness and use of hermetic storage among smallholder farmers. Only 53.3% of the interviewed farmers were aware of the use of hermetic storage for grain storage. The SuperGrain bag was the most known form of hermetic storage (35.3%), followed by the Purdue Improved Crop Storage (PICS) bag (34.9%), metallic silo (15.5%), and plastic silo (14.4%). Hermetic storage use was even lower as only 17.6% of the surveyed farmers were using one or more forms of hermetic storage to store their grains. Insect pest management without chemical insecticides was the main reason (83.1%) for hermetic storage use. About 75.5% of those aware of hermetic storage had received training in the technology. Hermetic storage use in farming households led to improved food availability, household income, and nutrition. Lack of local availability (50.2%), high costs (37.8%), and inadequate knowledge (6.9%) were the main constraints hindering the adoption of hermetic storage in Northern Uganda. The logit regression models showed that only training in hermetic storage significantly (p = 0.002) affected farmers’ decision to adopt hermetic storage. Understanding the factors that constrain the adoption of HSTs could provide policymakers with important information to initiate and design policies and programs aimed at reducing crop storage losses.
文摘The paper presents the change in grain-size composition of lignite under cyclic freezing-thawing (FTC) and wetting-drying (WDC). The article shows that in the spring and autumn periods the lignites can be subjected to repeated freezing-thawing and wetting-drying, which determines the possibility of changing their grain-size composition and structure. Experimental studies in laboratory conditions on the influence of cyclic freezing-thawing (FTC) and wetting-drying (WDC) on the quality indicators of lignites have been carried out, their granulometric (fractional) composition has been studied. Freezing-thawing cycle conditions are as follows (FTC): minimum exposure temperature: -20°C;maximum: +5°C;relative humidity: 30%;number of processing cycles: 3. Wetting-drying cycles are as follows (WDC): drying temperatures are +20, +40, +60, +80°C, drying time 90 minutes, the coals are further subjected to rain (soaking) for a period of water saturation to humidity of 30% - 40% and dry again. The number of wetting-drying cycles is 3 times. The tests have revealed the destructive effects of FTC and WDC on the samples of lower metamorphic grade coal, and the cycles of wet-dry lead to the much higher yield of fine sizes (-6+0;-13+0 mm) than the cycles of freeze-thaw. Furthermore, it is found that the increase in the yield of fines depends on the heating temperature: coal disintegration proceeds more intensively at a higher temperature of drying.
基金Supported by the National Natural Science Foundation of China(21476119,21406124)Major Science and Technology Innovation Project of Shandong Province(2018CXGC1102).
文摘The amount of low-temperature heat generated in industrial processes is high,but recycling is limited due to low grade and low recycling efficiency,which is one of the reasons for low energy efficiency.It implies that there is a great potential for low-temperature heat recovery and utilization.This article provided a detailed review of recent advances in the development of low-temperature thermal upgrades,power generation,refrigeration,and thermal energy storage.The detailed description will be given from the aspects of system structure improvement,work medium improvement,and thermodynamic and economic performance evaluation.It also pointed out the development bottlenecks and future development trends of various technologies.The low-temperature heat combined utilization technology can recover waste heat in an all-round and effective manner,and has great development prospects.
基金the National Natural Science Foundation of China (NSFC 50571072)
文摘The effect of KOH electrolyte concentration on low-temperature electrochemical properties of LaNi5 alloy electrodes at 233 K was studied. The results indicated that the electrolyte concentration had great influence on discharge capacity and discharge voltage plateau of LaNi5 alloy electrode at 233 K, and the highest discharge capacity and discharge voltage plateau were both obtained at 6 mol/L KOH. When the KOH electrolyte concentration changed from 5 to 9 mol/L at 233 K, the high rate discharge ability （HRD） had the same change tendency as the diffusion coefficient, but the exchange current density did not change significantly, which implied that hydrogen diffusion was the control step at low temperature 233 K for discharge process of LaNi5 alloy electrode.
文摘A dominant intrinsic luminescence band, which is due to the surface potential barriers of crystalline grains, and an edge doublet, which arises as an LO-phonon repetition of the e-h band, has been revealed in the low-temperature photoluminescence spectra of fine-grained obliquely deposited films. Doping film with In impurity leads to quenching of the doublet band, while further thermal treatment causes activation of the intrinsic band, the half-width and the blue shift of the red edge of which correlates with the maximum value of anomalously high photovoltage generated by the film.
基金The authors acknowledge the financial support from the National Natural Science Foundation of China(Nos.22101065 and 51972075)the Natural Science Foundation of Heilongjiang Province(No.YQ2021B001)+1 种基金the China Postdoctoral Science Foundation(No.2020M681075)the Fundamental Research Funds for the Central Universities.
文摘Nanostructured aluminum recently delivers a variety of new applications of the earth-abundant Al resource due to the unique properties,but its controllable synthesis remains very challenging with harsh conditions and spontaneously flammable precursors.Herein,a surface group directed method is developed to efficiently achieve low-temperature synthesis and selfassembly of zero-dimensional(0D)Al nanocrystals over one-dimensional(1D)carbon fibers(Al@CFs)through non-flammable AlCl3 reduction at 70°C.Theoretical calculations unveil surface‒OLi groups of carbon fibers exert efficient binding effect to AlCl3,which guides intimate adsorption and in-situ self-assembly of the generated Al nanocrystals.The distinctive 0D-over-1D Al@CFs provides long 1D conductive networks for electron transfer,ultrafine 0D Al nanocrystals for fast lithiation and excellent buffering effect for volume change,thus exhibiting high structure stability and superior lithium storage performance.This work paves the way for mild and controllable synthesis of Al-based nanomaterials for new high-value applications.
