The serious environmental threat caused by petroleum-based plastics has spurred more researches in developing substitutes from renewable sources.Starch is desirable for fabricating bioplastic due to its abundance and ...The serious environmental threat caused by petroleum-based plastics has spurred more researches in developing substitutes from renewable sources.Starch is desirable for fabricating bioplastic due to its abundance and renewable nature.However,limitations such as brittleness,hydrophilicity,and thermal properties restrict its widespread application.To overcome these issues,covalent adaptable network was constructed to fabricate a fully bio-based starch plastic with multiple advantages via Schiff base reactions.This strategy endowed starch plastic with excellent thermal processability,as evidenced by a low glass transition temperature(T_(g)=20.15℃).Through introducing Priamine with long carbon chains,the starch plastic demonstrated superior flexibility(elongation at break=45.2%)and waterproof capability(water contact angle=109.2°).Besides,it possessed a good thermal stability and self-adaptability,as well as solvent resistance and chemical degradability.This work provides a promising method to fabricate fully bio-based plastics as alternative to petroleum-based plastics.展开更多
Wheat allergy has become a serious health threat worldwide and its prevalence has increased alarmingly in the past few years.Factors such as food matrix and food processing may alter the structure of wheat proteins,an...Wheat allergy has become a serious health threat worldwide and its prevalence has increased alarmingly in the past few years.Factors such as food matrix and food processing may alter the structure of wheat proteins,and hence affect its allergenic properties.However,few reports have focused on the influence of Chinese traditional starter fermentation on wheat allergy.In this study,5 starters from different regions of China were used for fermentation,and protein characteristics were monitored by sodium dodecyl sulfate polyacrylamide gel electropheresis,and immunoreactivity analyzed by immunoassay with allergenic serum was obtained from New Zealand white rabbits.The allergenicity of steamed and baked matrices was also evaluated.The results showed that the allergenicity of wheat dough was basically increased at the beginning and then decreased during fermentation,but specific trends depend on different starters.With the progress of fermentation,especially as pH value decreased to 3.0-4.0,the allergenicity decreased significantly.Baking and steaming can reduce the allergenicity of wheat matrix,but fermentation is not a key factor affecting the allergenic activity of proteins.Our results can provide a theoretical basis for controlling wheat allergenicity in food proces sing or producing hypoallergenic food.展开更多
Qingke(highland hull-less barley)is a grain replete with substantial nutrients and bioactive ingredients.In this study,we evaluated the effects of boiling(BO),steaming(ST),microwave baking(MB),far-infrared baking(FB),...Qingke(highland hull-less barley)is a grain replete with substantial nutrients and bioactive ingredients.In this study,we evaluated the effects of boiling(BO),steaming(ST),microwave baking(MB),far-infrared baking(FB),steam explosion(SE),and deep frying(DF)on bioactive components,phenolic compounds,and antioxidant activities of Qingke compared with the effects of traditional roast(TR).Results showed that the soluble dietary fiber,beta-glucan and water-extractable pentosans of Qingke in dry heat processes of TR,SE,MB and FB had a higher content compared with other thermal methods and had a better antioxidant activity of hydroxyl radical scavenging and a better reduction capacity,while those in wet heat processes of BO and ST had a better antioxidant activity of ABTS radical scavenging and a better Fe^(2+) chelating ability.DF-and SE-Qingke had a higher content of tocopherol,phenolic,and flavonoid.Overall,6 free phenolic compounds and 12 bound phenolic compounds of Qingke were identified,and free phenolic compounds suffered more damage during thermal processing.Principal component analysis showed that SE had more advantages in retaining and improving the main biological active ingredients of Qingke,and it may be the best method for treating Qingke.展开更多
The bearing capacity of pile foundations is affected by the temperature of the frozen soil around pile foundations.The construction process and the hydration heat of cast-in-place(CIP)pile foundations affect the therm...The bearing capacity of pile foundations is affected by the temperature of the frozen soil around pile foundations.The construction process and the hydration heat of cast-in-place(CIP)pile foundations affect the thermal stability of permafrost.In this paper,temperature data from inside multiple CIP piles,borehole observations of ground thermal status adjacent to the foundations and local weather stations were monitored in warm permafrost regions to study the thermal influence process of CIP pile foundations.The following conclusions are drawn from the field observation data.(1)The early temperature change process of different CIP piles is different,and the differences gradually diminish over time.(2)The initial concrete temperature is linearly related with the air temperature,net radiation and wind speed within 1 h before the completion of concrete pouring;the contributions of the air temperature,net radiation,and wind speed to the initial concrete temperature are 51.9%,20.3%and 27.9%,respectively.(3)The outer boundary of the thermal disturbance annulus is approximately 2 m away from the pile center.It took more than 224 days for the soil around the CIP piles to return to the natural permafrost temperature at the study site.展开更多
The safety valve is an important component to ensure the safe operation of lithium-ion batteries(LIBs).However,the effect of safety valve type on the thermal runaway(TR)and gas venting behavior of LIBs,as well as the ...The safety valve is an important component to ensure the safe operation of lithium-ion batteries(LIBs).However,the effect of safety valve type on the thermal runaway(TR)and gas venting behavior of LIBs,as well as the TR hazard severity of LIBs,are not known.In this paper,the TR and gas venting behavior of three 100 A h lithium iron phosphate(LFP)batteries with different safety valves are investigated under overheating.Compared to previous studies,the main contribution of this work is in studying and evaluating the effect of gas venting behavior and TR hazard severity of LFP batteries with three safety valve types.Two significant results are obtained:(Ⅰ)the safety valve type dominates over gas venting pressure of battery during safety venting,the maximum gas venting pressure of LFP batteries with a round safety valve is 3320 Pa,which is one order of magnitude higher than other batteries with oval or cavity safety valve;(Ⅱ)the LFP battery with oval safety valve has the lowest TR hazard as shown by the TR hazard assessment model based on gray-fuzzy analytic hierarchy process.This study reveals the effect of safety valve type on TR and gas venting,providing a clear direction for the safety valve design.展开更多
The purpose of this study is to evaluate the Spectral Angle Mapper (SAM) classification method for determining the optimum threshold (maximum spectral angle) to unveil the hydrothermal mineral assemblages related ...The purpose of this study is to evaluate the Spectral Angle Mapper (SAM) classification method for determining the optimum threshold (maximum spectral angle) to unveil the hydrothermal mineral assemblages related to mineral deposits. The study area indicates good potential for Cu-Au porphyry, epithermal gold deposits and hydrothermal alteration well developed in arid and semiarid climates, which makes this region significant for Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image processing analysis. Given that achieving an acceptable mineral mapping requires knowing the alteration patterns, petrochemistry and petrogenesis of the igneous rocks while considering the effect of weathering, overprinting of supergene alteration, overprinting of hypogene alteration and host rock spectral mixing, SAM classification was implemented for argillic, sericitic, propylitic, alunitization, silicification and iron oxide zones of six previously known mineral deposits: Maherabad, a Cu-Au porphyry system; Sheikhabad, an upper part of Cu-Au porphyry system; Khoonik, an Intrusion related Au system; Barmazid, a low sulfidation epithermal system; Khopik, a Cu-Au porphyry system; and Hanish, an epithermal Au system. Thus, the investigation showed that although the whole alteration zones are affected by mixing, it is also possible to produce a favorable hydrothermal mineral map by such complementary data as petrology, petrochemistry and alteration patterns.展开更多
Engineering point defects such as metal and oxygen vacancies play a crucial role in manipulating the electrical,optical,and catalytic properties of oxide semiconductors for solar water splitting.Herein,we synthesized ...Engineering point defects such as metal and oxygen vacancies play a crucial role in manipulating the electrical,optical,and catalytic properties of oxide semiconductors for solar water splitting.Herein,we synthesized nanoporous CuBi_(2)O_(4)(np-CBO)photocathodes and engineered their surface point defects via rapid thermal processing(RTP)in controlled atmospheres(O_(2),N_(2),and vacuum).We found that the O_(2)-RTP treatment of np-CBO increased the charge carrier density effectively without hampering the nanoporous morphology,which was attributed to the formation of copper vacancies(VCu).Further analyses revealed that the amounts of oxygen vacancies(Vo)and Cu^(1+)were reduced simultaneously,and the relative electrochemical active surface area increased after the O_(2)-RTP treatment.Notably,the point defects(VC_(u),Cu^(1+),and Vo)regulated np-CBO achieved a superb water-splitting photocurrent density of-1.81 m A cm^(-2) under simulated sunlight illumination,which is attributed to the enhanced charge transport and transfer properties resulting from the regulated surface point defects.Finally,the reversibility of the formation of the point defects was checked by sequential RTP treatments(O_(2)-N_(2)-O_(2)-N_(2)),demonstrating the strong dependence of photocurrent response on the RTP cycles.Conclusively,the surface point defect engineering via RTP treatment in a controlled atmosphere is a rapid and facile strategy to promote charge transport and transfer properties of photoelectrodes for efficient solar water-splitting.展开更多
Heavy oil represents a vital petroleum resource worldwide.As one of the major producers,China is facing great challenges in effective and economic production of heavy oil due to reservoir complexity.Plenty of efforts ...Heavy oil represents a vital petroleum resource worldwide.As one of the major producers,China is facing great challenges in effective and economic production of heavy oil due to reservoir complexity.Plenty of efforts have been made to promote innovative advances in thermal recovery modes,methods,and processes for heavy oil in the country.The thermal recovery mode has been shifted from simple steam injection to a more comprehensive“thermal+"strategy,such as a novel N2-steam hybrid process and CO_(2)-enhanced thermal recovery techniques.These advanced techniques break through the challenges of heavy oil extraction from less accessible reservoirs with thinner oil layers and greater burial depths.Regarding thermal recovery methods,China has developed the steam-assisted gravity drainage method integrating flooding and drainage(also referred to as the hybrid flooding-drainage SAGD technology)for highly heterogeneous ultra-heavy oil reservoirs and the fire flooding method for nearly depleted heavy oil reservoirs,substantially improving oil recovery.Furthermore,a range of processes have been developed for heavy oil production,including the open hole completion process using sand control screens for horizontal wells,the process of integrated injection-recovery with horizontal pump for horizontal wells,the steam dryness maintenance,measurement,and control process,efficient and environment-friendly circulating fluidized bed(CFB)boilers with high steam dryness,the recycling process of produced water,and the thermal recovery process for offshore heavy oil.Based on the advances in methodology,technology,and philosophy,a series of supporting technologies for heavy oil production have been developed,leading to the breakthrough of existing technical limit of heavy oil recovery and the expansion into new exploitation targets.For the future heavy oil production in China,it is necessary to embrace a green,low-carbon,and energy-efficient development strategy,and to expand heavy oil extraction in reservoirs with larger burial depth,more viscous oil,thinner oil layers,and lower permeability.Moreover,it is highly recommended to collaboratively maximize oil recovery and oil-to-steam ratio through technological innovations,and boost intelligentization of heavy oil production.展开更多
To increase the processability and plasticity of the selective laser melting(SLM)fabricated Al-Mn-Mg-Er-Zr alloys,a novel TiB_(2)-modified Al-Mn-Mg-Er-Zr alloy with a mixture of Al-Mn-Mg-Er-Zr and nano-TiB_(2) powders...To increase the processability and plasticity of the selective laser melting(SLM)fabricated Al-Mn-Mg-Er-Zr alloys,a novel TiB_(2)-modified Al-Mn-Mg-Er-Zr alloy with a mixture of Al-Mn-Mg-Er-Zr and nano-TiB_(2) powders was fabricated by SLM.The pro-cessability,microstructure,and mechanical properties of the alloy were systematically investigated by density measurement,microstruc-ture characterization,and mechanical properties testing.The alloys fabricated at 250 W displayed higher relative densities due to a uni-formly smooth top surface and appropriate laser energy input.The maximum relative density value of the alloy reached(99.7±0.1)%,demonstrating good processability.The alloy exhibited a duplex grain microstructure consisting of columnar regions primarily and equiaxed regions with TiB_(2),Al6Mn,and Al3Er phases distributed along the grain boundaries.After directly aging treatment at a high tem-perature of 400℃,the strength of the SLM-fabricated TiB_(2)/Al-Mn-Mg-Er-Zr alloy increased due to the precipitation of the secondary Al6Mn phases.The maximum yield strength and ultimate tensile strength of the aging alloy were measured to be(374±1)and(512±13)MPa,respectively.The SLM-fabricated TiB_(2)/Al-Mn-Mg-Er-Zr alloy demonstrates exceptional strength and thermal stability due to the synergistic effects of the inhibition of grain growth,the incorporation of TiB_(2) nanoparticles,and the precipitation of secondary Al6Mn nanoparticles.展开更多
The relationship between the arrangement of tungsten-halogen lamps and the uniformity of irradiance received by the wafer is discussed, and a sort of axial-symmetrical lamps-array is designed to guarantee that the irr...The relationship between the arrangement of tungsten-halogen lamps and the uniformity of irradiance received by the wafer is discussed, and a sort of axial-symmetrical lamps-array is designed to guarantee that the irradiation on the edge is approximately the same as the one on the center of the wafer. The magnitude of temperature on the wafer vs. the power of tungsten-halogen lamps is calculated numerically.展开更多
As global warming intensifies, researchers worldwide strive to develop effective ways to reduce heat transfer. Among the natural fiber composites studied extensively in recent decades, bamboo has emerged as a prime ca...As global warming intensifies, researchers worldwide strive to develop effective ways to reduce heat transfer. Among the natural fiber composites studied extensively in recent decades, bamboo has emerged as a prime candidate for reinforcement. This woody plant offers inherent strengths, biodegradability, and abundant availability. Due to its high cellulose content, its low thermal conductivity establishes bamboo as a thermally resistant material. Its low thermal conductivity, enhanced by a NaOH solution treatment, makes it an excellent thermally resistant material. Researchers incorporated Hollow Glass Microspheres (HGM) and Kaolin fillers into the epoxy matrix to improve the insulating properties of bamboo composites. These fillers substantially enhance thermal resistance, limiting heat transfer. Various compositions, like (30% HGM + 25% Bamboo + 65% Epoxy) and (30% Kaolin + 25% Bamboo + 45% Epoxy), were compared to identify the most efficient thermal insulator. Using Vacuum Assisted Resin Transfer Molding (VARTM) ensures uniform distribution of fillers and resin, creating a structurally sound thermal barrier. These reinforced composites, evaluated using the TOPSIS method, demonstrated their potential as high-performance materials combating heat transfer, offering a promising solution in the battle against climate change.展开更多
Hybrid organic-inorganic polymer nanocomposites incorporating organically modified montmorillonite (MMT) and ultra-high molecular weight polyethylene (UHMWPE) were examined. UHMWPE/MMT hybrid nanocomposites were prepa...Hybrid organic-inorganic polymer nanocomposites incorporating organically modified montmorillonite (MMT) and ultra-high molecular weight polyethylene (UHMWPE) were examined. UHMWPE/MMT hybrid nanocomposites were prepared using gel and pressure-induced flow(PIF) processing methods at a gel weight concentration of 8% UHMWPE with various organoclay contents (0, 0.4, 0.8, 1.2, and 1.6 parts per hundred parts). The interlayer properties of the nanocomposites were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The thermal and mechanical interfacial properties of the nanocomposites were investigated through thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and the use of a universal test machine (UTM). TEM indicates that the nanocomposites are formed upon dispersion of MMT in the polymer matrix. From the DSC, TGA, and DMA results, we find that the thermal stability of the UHMWPE nanocomposites increases as the MMT content increases. The nanocomposites show higher tensile strengths than pure UHMWPE gel sheet. These findings indicate that the interfacial and mechanical properties are improved by the addition of MMT and PIF processing.展开更多
In an effort to reduce vehicle collisions with snowplows in poor weather conditions, this paper details the development of a real time thermal image based machine learning approach to an early collision avoidance syst...In an effort to reduce vehicle collisions with snowplows in poor weather conditions, this paper details the development of a real time thermal image based machine learning approach to an early collision avoidance system for snowplows, which intends to detect and estimate the distance of trailing vehicles. Due to the operational conditions of snowplows, which include heavy-blowing snow, traditional optical sensors like LiDAR and visible spectrum cameras have reduced effectiveness in detecting objects in such environments. Thus, we propose using a thermal infrared camera as the primary sensor along with machine learning algorithms. First, we curate a large dataset of thermal images of vehicles in heavy snow conditions. Using the curated dataset, two machine-learning models based on the modified ResNet architectures were trained to detect and estimate the trailing vehicle distance using real-time thermal images. The trained detection network was capable of detecting trailing vehicles 99.0% of the time at 1500.0 ft distance from the snowplow. The trained trailing distance network was capable of estimating distance with an average estimation error of 10.70 ft. The inference performance of the trained models is discussed, along with the interpretation of the performance.展开更多
The materials used in variable temperature conditions are required to have excellent thermal fatigue performance.The effects of laser shock processing(LSP),solid solution and aging treatment(T6),and cryogenic treatmen...The materials used in variable temperature conditions are required to have excellent thermal fatigue performance.The effects of laser shock processing(LSP),solid solution and aging treatment(T6),and cryogenic treatment(CT)on both microstructure and thermal fatigue performance of ZCuAl_(10)Fe_(3)Mn_(2) alloys were studied.Microstructure and crack morphology were then examined by scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS).The result showed that,after being subjected to the combination treatment of T6+CT+LSP,the optimal mechanical properties and thermal fatigue performance were obtained for the ZCuAl_(10)Fe_(3)Mn_(2) alloy with the tensile strength,hardness,and elongation of 720 MPa,300.16 HB,and 16%,respectively,and the thermal fatigue life could reach 7,100 cycles when the crack length was 0.1 mm.Moreover,the ZCuAl_(10)Fe_(3)Mn_(2) after combination treatment shows high resistance to oxidation,good adhesion between the matrix and grain boundaries,and dramatically reduced growth rate of crack.During thermal fatigue testing,under the combined action of thermal and alternating stresses,the microstructure around the sample notch oxidized and became loose and porous,which then converted to micro-cracks.Fatigue crack expanded along the grain boundary in the early stage.In the later stage,under the cyclic stress accumulation,the oxidized microstructure separated from the matrix,and the fatigue crack expanded in both intergranular and transgranular ways.The main crack was thick,and the path was meandering.展开更多
A novel bat-like ZnO nanostructure was synthesized on the silicon substrate by simple ther- mal evaporation of zinc powders without any catalyst. Each bat-like nanorod ("nanobat") is composed of a hexagonal head, ...A novel bat-like ZnO nanostructure was synthesized on the silicon substrate by simple ther- mal evaporation of zinc powders without any catalyst. Each bat-like nanorod ("nanobat") is composed of a hexagonal head, a continuous neck and a thin handle. High-resolution transmission electron microscopy and selected area electron diffraction results reveal the single-crystalline feature and the growing direction along [0001] of the nanobat. The vapor- solid mechanism was found suitable to explain the growth process of the nanobat and a schematic model was proposed in detail based on the experimental results.展开更多
The direct conversion of methane using a dielectric barrier discharge has been experimentally studied. Experiments with different values of flow rates and discharge voltages have been performed to investigate the effe...The direct conversion of methane using a dielectric barrier discharge has been experimentally studied. Experiments with different values of flow rates and discharge voltages have been performed to investigate the effects on the conversion and reaction products both qualitatively and quantitatively. Experimental results indicate that the maximum conversion of methane has been 80% at an input flow rate of 5 ml/min and a discharge voltage of 4 kV. Experimental results also show that the optimum condition has occurred at a high discharge voltage and higher input flow rate. In terms of product distribution, a higher flow rate or shorter residence time can increase the selectivity for higher hydrocarbons. No hydrocarbon product was detected using the thermal method, except hydrogen and carbon. Increasing selectivity for ethane was found when Pt and Ru catalysts presented in the plasma reaction. Hydrogenation of acetylene in the catalyst surface could have been the reason for this phenomenon as the selectivity for acetylene in the products was decreasing.展开更多
Up to now, the Pedgion magnesium reduction process is the dominating magnesium production process. In 2004, about 98% of raw magnesium is produced by Pedgion magnesium reduction process in China which equals to 60% of...Up to now, the Pedgion magnesium reduction process is the dominating magnesium production process. In 2004, about 98% of raw magnesium is produced by Pedgion magnesium reduction process in China which equals to 60% of the global output. It shows that the dolomite-ferrosilicon thermal reduction process is the most important method to produce magnesium in the world. Limited by the disadvantage of dolomite-ferrosilicon thermal reduction process, the magnesium producing process always followed by relatively severe pollution, while the resource utilizing efficiency keeps very low. With the rapid development of dolomite-ferrosilicon thermal reduction process in China, many research works have been done aiming at the process technology and the reduction theory, and the magnesium producing process has got great evolution. The history of dolomite-ferrosilicon thermal reduction process was introduced; the process character, the merits and which defects were also discussed. Defects in dolomite-ferrosilicon thermal reduction process were expatiated, and feasible method and idea to upgrade the process was put forward. The main problems and the potential troubles hindering the development of magnesium industry were analyzed. Finally, the probability to further improve the thermal reduction process and the effective approaches to develop Chinese magnesium industry were discussed.展开更多
Continuous thermo-mechanical processing (CTMP) of 6201 aluminum alloy was simulated on Gleeble-1500. The deformed specimens were analyzed by the observation of TEM and the measurement of hardness. It was shown that r...Continuous thermo-mechanical processing (CTMP) of 6201 aluminum alloy was simulated on Gleeble-1500. The deformed specimens were analyzed by the observation of TEM and the measurement of hardness. It was shown that rapid solid solution and aging treatment can be effectively combined in one procedure by the strain induced during CTMP. The deformation temperature is ranging from 540* C to 300* C, the hardness increases directly before the 6th pass followed by a slight drop, the amount of precipitates increases with the holding time after deformation. Uniformly distributed and stabilized Mg2Si precipitates, as well as dislocation substructure can be observed on deformed specimens which have been subsequently held at 300℃ for 60 seconds.展开更多
Abstract: Thermochronological dating was used to study the thermal evolution of the Mesozoic plutons and uplift history of the Yanshan orogenic belt. The results show that the cooling history of the plutons is complic...Abstract: Thermochronological dating was used to study the thermal evolution of the Mesozoic plutons and uplift history of the Yanshan orogenic belt. The results show that the cooling history of the plutons is complicated, corresponding to the inhomogeneous uplift process of the Yanshan orogenic belt. The Panshan granite cooled fast during 226.48–204.95 Ma at a rate of 10.22°C/Ma after its emplacement at a depth of about 10 km, and its fast uplift occurred in about 96–35 Ma at an average rate of 0.115 mm/a. The Wulingshan pluton cooled fast during 132–127.23 Ma at a rate of 94.34°C/Ma, and its rapid uplift occurred in 86–45 Ma at an average rate of 0.186 mm/a. The Yunmengshan granite cooled fast during 143–120.99 Ma at a rate of 19.51°C/Ma, and its rapid uplift occurred in 106–103.95 Ma and 20–0.0 Ma at a rate of 1.06 mm/a and 0.15 mm/a respectively. The Sihetang granite-gneiss uplifted rapidly since 13 Ma at an average rate of 0.256 mm/a. The Badaling granite uplifted rapidly since 6 Ma at an average rate of 0.556 mm/a. The Cenozoic uplift of the Yanshan Mountains can be well correlated to the rifting process of the surrounding basins.展开更多
基金supported by the National Natural Science Foundation of China(U23A6005 and 32171721)State Key Laboratory of Pulp and Paper Engineering(202305,2023ZD01,2023C02)+1 种基金Guangdong Province Basic and Application Basic Research Fund(2023B1515040013)the Fundamental Research Funds for the Central Universities(2023ZYGXZR045).
文摘The serious environmental threat caused by petroleum-based plastics has spurred more researches in developing substitutes from renewable sources.Starch is desirable for fabricating bioplastic due to its abundance and renewable nature.However,limitations such as brittleness,hydrophilicity,and thermal properties restrict its widespread application.To overcome these issues,covalent adaptable network was constructed to fabricate a fully bio-based starch plastic with multiple advantages via Schiff base reactions.This strategy endowed starch plastic with excellent thermal processability,as evidenced by a low glass transition temperature(T_(g)=20.15℃).Through introducing Priamine with long carbon chains,the starch plastic demonstrated superior flexibility(elongation at break=45.2%)and waterproof capability(water contact angle=109.2°).Besides,it possessed a good thermal stability and self-adaptability,as well as solvent resistance and chemical degradability.This work provides a promising method to fabricate fully bio-based plastics as alternative to petroleum-based plastics.
基金supported by the National Natural Science Foundation of China(31872904)。
文摘Wheat allergy has become a serious health threat worldwide and its prevalence has increased alarmingly in the past few years.Factors such as food matrix and food processing may alter the structure of wheat proteins,and hence affect its allergenic properties.However,few reports have focused on the influence of Chinese traditional starter fermentation on wheat allergy.In this study,5 starters from different regions of China were used for fermentation,and protein characteristics were monitored by sodium dodecyl sulfate polyacrylamide gel electropheresis,and immunoreactivity analyzed by immunoassay with allergenic serum was obtained from New Zealand white rabbits.The allergenicity of steamed and baked matrices was also evaluated.The results showed that the allergenicity of wheat dough was basically increased at the beginning and then decreased during fermentation,but specific trends depend on different starters.With the progress of fermentation,especially as pH value decreased to 3.0-4.0,the allergenicity decreased significantly.Baking and steaming can reduce the allergenicity of wheat matrix,but fermentation is not a key factor affecting the allergenic activity of proteins.Our results can provide a theoretical basis for controlling wheat allergenicity in food proces sing or producing hypoallergenic food.
基金financially supported by the 2018 annual three gorges follow-up research project of the three gorges office of the State Council (YYNY-2017-01)
文摘Qingke(highland hull-less barley)is a grain replete with substantial nutrients and bioactive ingredients.In this study,we evaluated the effects of boiling(BO),steaming(ST),microwave baking(MB),far-infrared baking(FB),steam explosion(SE),and deep frying(DF)on bioactive components,phenolic compounds,and antioxidant activities of Qingke compared with the effects of traditional roast(TR).Results showed that the soluble dietary fiber,beta-glucan and water-extractable pentosans of Qingke in dry heat processes of TR,SE,MB and FB had a higher content compared with other thermal methods and had a better antioxidant activity of hydroxyl radical scavenging and a better reduction capacity,while those in wet heat processes of BO and ST had a better antioxidant activity of ABTS radical scavenging and a better Fe^(2+) chelating ability.DF-and SE-Qingke had a higher content of tocopherol,phenolic,and flavonoid.Overall,6 free phenolic compounds and 12 bound phenolic compounds of Qingke were identified,and free phenolic compounds suffered more damage during thermal processing.Principal component analysis showed that SE had more advantages in retaining and improving the main biological active ingredients of Qingke,and it may be the best method for treating Qingke.
基金supported by the Natural Science Foundation of China (Grants No.41101065)the State Key Laboratory of Frozen Soil Engineering Funds (SKLFSE-ZT-34,SKLFSE-ZQ-202103).
文摘The bearing capacity of pile foundations is affected by the temperature of the frozen soil around pile foundations.The construction process and the hydration heat of cast-in-place(CIP)pile foundations affect the thermal stability of permafrost.In this paper,temperature data from inside multiple CIP piles,borehole observations of ground thermal status adjacent to the foundations and local weather stations were monitored in warm permafrost regions to study the thermal influence process of CIP pile foundations.The following conclusions are drawn from the field observation data.(1)The early temperature change process of different CIP piles is different,and the differences gradually diminish over time.(2)The initial concrete temperature is linearly related with the air temperature,net radiation and wind speed within 1 h before the completion of concrete pouring;the contributions of the air temperature,net radiation,and wind speed to the initial concrete temperature are 51.9%,20.3%and 27.9%,respectively.(3)The outer boundary of the thermal disturbance annulus is approximately 2 m away from the pile center.It took more than 224 days for the soil around the CIP piles to return to the natural permafrost temperature at the study site.
基金supported by the National Key R&D Program of China(No.2021YFB2402001)the Postgraduate Innovation and Entrepreneurship Practice Project of Anhui Province(No.2022cxcysj013)+2 种基金the China Postdoctoral Science Foundation(No.2022T150615)the Fundamental Research Funds for the Central Universities(No.WK5290000002)supported by Youth Innovation Promotion Association CAS(No.Y201768)。
文摘The safety valve is an important component to ensure the safe operation of lithium-ion batteries(LIBs).However,the effect of safety valve type on the thermal runaway(TR)and gas venting behavior of LIBs,as well as the TR hazard severity of LIBs,are not known.In this paper,the TR and gas venting behavior of three 100 A h lithium iron phosphate(LFP)batteries with different safety valves are investigated under overheating.Compared to previous studies,the main contribution of this work is in studying and evaluating the effect of gas venting behavior and TR hazard severity of LFP batteries with three safety valve types.Two significant results are obtained:(Ⅰ)the safety valve type dominates over gas venting pressure of battery during safety venting,the maximum gas venting pressure of LFP batteries with a round safety valve is 3320 Pa,which is one order of magnitude higher than other batteries with oval or cavity safety valve;(Ⅱ)the LFP battery with oval safety valve has the lowest TR hazard as shown by the TR hazard assessment model based on gray-fuzzy analytic hierarchy process.This study reveals the effect of safety valve type on TR and gas venting,providing a clear direction for the safety valve design.
基金supported by National Geoscience Database and Geological Survey of Iran
文摘The purpose of this study is to evaluate the Spectral Angle Mapper (SAM) classification method for determining the optimum threshold (maximum spectral angle) to unveil the hydrothermal mineral assemblages related to mineral deposits. The study area indicates good potential for Cu-Au porphyry, epithermal gold deposits and hydrothermal alteration well developed in arid and semiarid climates, which makes this region significant for Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image processing analysis. Given that achieving an acceptable mineral mapping requires knowing the alteration patterns, petrochemistry and petrogenesis of the igneous rocks while considering the effect of weathering, overprinting of supergene alteration, overprinting of hypogene alteration and host rock spectral mixing, SAM classification was implemented for argillic, sericitic, propylitic, alunitization, silicification and iron oxide zones of six previously known mineral deposits: Maherabad, a Cu-Au porphyry system; Sheikhabad, an upper part of Cu-Au porphyry system; Khoonik, an Intrusion related Au system; Barmazid, a low sulfidation epithermal system; Khopik, a Cu-Au porphyry system; and Hanish, an epithermal Au system. Thus, the investigation showed that although the whole alteration zones are affected by mixing, it is also possible to produce a favorable hydrothermal mineral map by such complementary data as petrology, petrochemistry and alteration patterns.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea,funded by the Ministry of Science,ICT,and Future Planning(NRF Award No.NRF-2019R1A2C2002024 and 2021R1A4A1031357)supported by the Basic Science Research Program through NRF funded by the Ministry of Education(NRF Award No.NRF2020R1A6A1A03043435)。
文摘Engineering point defects such as metal and oxygen vacancies play a crucial role in manipulating the electrical,optical,and catalytic properties of oxide semiconductors for solar water splitting.Herein,we synthesized nanoporous CuBi_(2)O_(4)(np-CBO)photocathodes and engineered their surface point defects via rapid thermal processing(RTP)in controlled atmospheres(O_(2),N_(2),and vacuum).We found that the O_(2)-RTP treatment of np-CBO increased the charge carrier density effectively without hampering the nanoporous morphology,which was attributed to the formation of copper vacancies(VCu).Further analyses revealed that the amounts of oxygen vacancies(Vo)and Cu^(1+)were reduced simultaneously,and the relative electrochemical active surface area increased after the O_(2)-RTP treatment.Notably,the point defects(VC_(u),Cu^(1+),and Vo)regulated np-CBO achieved a superb water-splitting photocurrent density of-1.81 m A cm^(-2) under simulated sunlight illumination,which is attributed to the enhanced charge transport and transfer properties resulting from the regulated surface point defects.Finally,the reversibility of the formation of the point defects was checked by sequential RTP treatments(O_(2)-N_(2)-O_(2)-N_(2)),demonstrating the strong dependence of photocurrent response on the RTP cycles.Conclusively,the surface point defect engineering via RTP treatment in a controlled atmosphere is a rapid and facile strategy to promote charge transport and transfer properties of photoelectrodes for efficient solar water-splitting.
基金funded by a project of the National Natural Science Foundation of China entitled Basic study on mechanisms and key technologies of high efficiency hybrid multi-element thermal recovery in marginal heavy oil reservoirs(No.U20B6003).
文摘Heavy oil represents a vital petroleum resource worldwide.As one of the major producers,China is facing great challenges in effective and economic production of heavy oil due to reservoir complexity.Plenty of efforts have been made to promote innovative advances in thermal recovery modes,methods,and processes for heavy oil in the country.The thermal recovery mode has been shifted from simple steam injection to a more comprehensive“thermal+"strategy,such as a novel N2-steam hybrid process and CO_(2)-enhanced thermal recovery techniques.These advanced techniques break through the challenges of heavy oil extraction from less accessible reservoirs with thinner oil layers and greater burial depths.Regarding thermal recovery methods,China has developed the steam-assisted gravity drainage method integrating flooding and drainage(also referred to as the hybrid flooding-drainage SAGD technology)for highly heterogeneous ultra-heavy oil reservoirs and the fire flooding method for nearly depleted heavy oil reservoirs,substantially improving oil recovery.Furthermore,a range of processes have been developed for heavy oil production,including the open hole completion process using sand control screens for horizontal wells,the process of integrated injection-recovery with horizontal pump for horizontal wells,the steam dryness maintenance,measurement,and control process,efficient and environment-friendly circulating fluidized bed(CFB)boilers with high steam dryness,the recycling process of produced water,and the thermal recovery process for offshore heavy oil.Based on the advances in methodology,technology,and philosophy,a series of supporting technologies for heavy oil production have been developed,leading to the breakthrough of existing technical limit of heavy oil recovery and the expansion into new exploitation targets.For the future heavy oil production in China,it is necessary to embrace a green,low-carbon,and energy-efficient development strategy,and to expand heavy oil extraction in reservoirs with larger burial depth,more viscous oil,thinner oil layers,and lower permeability.Moreover,it is highly recommended to collaboratively maximize oil recovery and oil-to-steam ratio through technological innovations,and boost intelligentization of heavy oil production.
基金supported by the National Natural Science Foundation of China(Nos.51801079 and 52001140)the Portugal National Funds through Fundação para a Ciência e a Tecnologia Project(No.2021.04115).
文摘To increase the processability and plasticity of the selective laser melting(SLM)fabricated Al-Mn-Mg-Er-Zr alloys,a novel TiB_(2)-modified Al-Mn-Mg-Er-Zr alloy with a mixture of Al-Mn-Mg-Er-Zr and nano-TiB_(2) powders was fabricated by SLM.The pro-cessability,microstructure,and mechanical properties of the alloy were systematically investigated by density measurement,microstruc-ture characterization,and mechanical properties testing.The alloys fabricated at 250 W displayed higher relative densities due to a uni-formly smooth top surface and appropriate laser energy input.The maximum relative density value of the alloy reached(99.7±0.1)%,demonstrating good processability.The alloy exhibited a duplex grain microstructure consisting of columnar regions primarily and equiaxed regions with TiB_(2),Al6Mn,and Al3Er phases distributed along the grain boundaries.After directly aging treatment at a high tem-perature of 400℃,the strength of the SLM-fabricated TiB_(2)/Al-Mn-Mg-Er-Zr alloy increased due to the precipitation of the secondary Al6Mn phases.The maximum yield strength and ultimate tensile strength of the aging alloy were measured to be(374±1)and(512±13)MPa,respectively.The SLM-fabricated TiB_(2)/Al-Mn-Mg-Er-Zr alloy demonstrates exceptional strength and thermal stability due to the synergistic effects of the inhibition of grain growth,the incorporation of TiB_(2) nanoparticles,and the precipitation of secondary Al6Mn nanoparticles.
基金Foundationfor Key Youth Teachers from Hunan Province(521105237) Natural Science Foundation of HunanUniversity(521101805)
文摘The relationship between the arrangement of tungsten-halogen lamps and the uniformity of irradiance received by the wafer is discussed, and a sort of axial-symmetrical lamps-array is designed to guarantee that the irradiation on the edge is approximately the same as the one on the center of the wafer. The magnitude of temperature on the wafer vs. the power of tungsten-halogen lamps is calculated numerically.
文摘As global warming intensifies, researchers worldwide strive to develop effective ways to reduce heat transfer. Among the natural fiber composites studied extensively in recent decades, bamboo has emerged as a prime candidate for reinforcement. This woody plant offers inherent strengths, biodegradability, and abundant availability. Due to its high cellulose content, its low thermal conductivity establishes bamboo as a thermally resistant material. Its low thermal conductivity, enhanced by a NaOH solution treatment, makes it an excellent thermally resistant material. Researchers incorporated Hollow Glass Microspheres (HGM) and Kaolin fillers into the epoxy matrix to improve the insulating properties of bamboo composites. These fillers substantially enhance thermal resistance, limiting heat transfer. Various compositions, like (30% HGM + 25% Bamboo + 65% Epoxy) and (30% Kaolin + 25% Bamboo + 45% Epoxy), were compared to identify the most efficient thermal insulator. Using Vacuum Assisted Resin Transfer Molding (VARTM) ensures uniform distribution of fillers and resin, creating a structurally sound thermal barrier. These reinforced composites, evaluated using the TOPSIS method, demonstrated their potential as high-performance materials combating heat transfer, offering a promising solution in the battle against climate change.
基金National Natural Science Foundations of China (No. 50833002, No. 20774018)
文摘Hybrid organic-inorganic polymer nanocomposites incorporating organically modified montmorillonite (MMT) and ultra-high molecular weight polyethylene (UHMWPE) were examined. UHMWPE/MMT hybrid nanocomposites were prepared using gel and pressure-induced flow(PIF) processing methods at a gel weight concentration of 8% UHMWPE with various organoclay contents (0, 0.4, 0.8, 1.2, and 1.6 parts per hundred parts). The interlayer properties of the nanocomposites were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The thermal and mechanical interfacial properties of the nanocomposites were investigated through thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and the use of a universal test machine (UTM). TEM indicates that the nanocomposites are formed upon dispersion of MMT in the polymer matrix. From the DSC, TGA, and DMA results, we find that the thermal stability of the UHMWPE nanocomposites increases as the MMT content increases. The nanocomposites show higher tensile strengths than pure UHMWPE gel sheet. These findings indicate that the interfacial and mechanical properties are improved by the addition of MMT and PIF processing.
文摘In an effort to reduce vehicle collisions with snowplows in poor weather conditions, this paper details the development of a real time thermal image based machine learning approach to an early collision avoidance system for snowplows, which intends to detect and estimate the distance of trailing vehicles. Due to the operational conditions of snowplows, which include heavy-blowing snow, traditional optical sensors like LiDAR and visible spectrum cameras have reduced effectiveness in detecting objects in such environments. Thus, we propose using a thermal infrared camera as the primary sensor along with machine learning algorithms. First, we curate a large dataset of thermal images of vehicles in heavy snow conditions. Using the curated dataset, two machine-learning models based on the modified ResNet architectures were trained to detect and estimate the trailing vehicle distance using real-time thermal images. The trained detection network was capable of detecting trailing vehicles 99.0% of the time at 1500.0 ft distance from the snowplow. The trained trailing distance network was capable of estimating distance with an average estimation error of 10.70 ft. The inference performance of the trained models is discussed, along with the interpretation of the performance.
基金National Natural Science Foundation of China(51801076)Natural Science Research of Jiangsu Higher Education Institutions of China(18KJB430009)+1 种基金Jiangsu Province Postdoctoral Science Foundation(1601055C)Senior Talents Research Startup of Jiangsu University(14JDG126)。
文摘The materials used in variable temperature conditions are required to have excellent thermal fatigue performance.The effects of laser shock processing(LSP),solid solution and aging treatment(T6),and cryogenic treatment(CT)on both microstructure and thermal fatigue performance of ZCuAl_(10)Fe_(3)Mn_(2) alloys were studied.Microstructure and crack morphology were then examined by scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS).The result showed that,after being subjected to the combination treatment of T6+CT+LSP,the optimal mechanical properties and thermal fatigue performance were obtained for the ZCuAl_(10)Fe_(3)Mn_(2) alloy with the tensile strength,hardness,and elongation of 720 MPa,300.16 HB,and 16%,respectively,and the thermal fatigue life could reach 7,100 cycles when the crack length was 0.1 mm.Moreover,the ZCuAl_(10)Fe_(3)Mn_(2) after combination treatment shows high resistance to oxidation,good adhesion between the matrix and grain boundaries,and dramatically reduced growth rate of crack.During thermal fatigue testing,under the combined action of thermal and alternating stresses,the microstructure around the sample notch oxidized and became loose and porous,which then converted to micro-cracks.Fatigue crack expanded along the grain boundary in the early stage.In the later stage,under the cyclic stress accumulation,the oxidized microstructure separated from the matrix,and the fatigue crack expanded in both intergranular and transgranular ways.The main crack was thick,and the path was meandering.
基金Project (50405026) supported by the National Natural Science Foundation of China Project(20051022) supported by the Department of Science and Technology of Shanxi Province, China
文摘A novel bat-like ZnO nanostructure was synthesized on the silicon substrate by simple ther- mal evaporation of zinc powders without any catalyst. Each bat-like nanorod ("nanobat") is composed of a hexagonal head, a continuous neck and a thin handle. High-resolution transmission electron microscopy and selected area electron diffraction results reveal the single-crystalline feature and the growing direction along [0001] of the nanobat. The vapor- solid mechanism was found suitable to explain the growth process of the nanobat and a schematic model was proposed in detail based on the experimental results.
文摘The direct conversion of methane using a dielectric barrier discharge has been experimentally studied. Experiments with different values of flow rates and discharge voltages have been performed to investigate the effects on the conversion and reaction products both qualitatively and quantitatively. Experimental results indicate that the maximum conversion of methane has been 80% at an input flow rate of 5 ml/min and a discharge voltage of 4 kV. Experimental results also show that the optimum condition has occurred at a high discharge voltage and higher input flow rate. In terms of product distribution, a higher flow rate or shorter residence time can increase the selectivity for higher hydrocarbons. No hydrocarbon product was detected using the thermal method, except hydrogen and carbon. Increasing selectivity for ethane was found when Pt and Ru catalysts presented in the plasma reaction. Hydrogenation of acetylene in the catalyst surface could have been the reason for this phenomenon as the selectivity for acetylene in the products was decreasing.
文摘Up to now, the Pedgion magnesium reduction process is the dominating magnesium production process. In 2004, about 98% of raw magnesium is produced by Pedgion magnesium reduction process in China which equals to 60% of the global output. It shows that the dolomite-ferrosilicon thermal reduction process is the most important method to produce magnesium in the world. Limited by the disadvantage of dolomite-ferrosilicon thermal reduction process, the magnesium producing process always followed by relatively severe pollution, while the resource utilizing efficiency keeps very low. With the rapid development of dolomite-ferrosilicon thermal reduction process in China, many research works have been done aiming at the process technology and the reduction theory, and the magnesium producing process has got great evolution. The history of dolomite-ferrosilicon thermal reduction process was introduced; the process character, the merits and which defects were also discussed. Defects in dolomite-ferrosilicon thermal reduction process were expatiated, and feasible method and idea to upgrade the process was put forward. The main problems and the potential troubles hindering the development of magnesium industry were analyzed. Finally, the probability to further improve the thermal reduction process and the effective approaches to develop Chinese magnesium industry were discussed.
文摘Continuous thermo-mechanical processing (CTMP) of 6201 aluminum alloy was simulated on Gleeble-1500. The deformed specimens were analyzed by the observation of TEM and the measurement of hardness. It was shown that rapid solid solution and aging treatment can be effectively combined in one procedure by the strain induced during CTMP. The deformation temperature is ranging from 540* C to 300* C, the hardness increases directly before the 6th pass followed by a slight drop, the amount of precipitates increases with the holding time after deformation. Uniformly distributed and stabilized Mg2Si precipitates, as well as dislocation substructure can be observed on deformed specimens which have been subsequently held at 300℃ for 60 seconds.
文摘Abstract: Thermochronological dating was used to study the thermal evolution of the Mesozoic plutons and uplift history of the Yanshan orogenic belt. The results show that the cooling history of the plutons is complicated, corresponding to the inhomogeneous uplift process of the Yanshan orogenic belt. The Panshan granite cooled fast during 226.48–204.95 Ma at a rate of 10.22°C/Ma after its emplacement at a depth of about 10 km, and its fast uplift occurred in about 96–35 Ma at an average rate of 0.115 mm/a. The Wulingshan pluton cooled fast during 132–127.23 Ma at a rate of 94.34°C/Ma, and its rapid uplift occurred in 86–45 Ma at an average rate of 0.186 mm/a. The Yunmengshan granite cooled fast during 143–120.99 Ma at a rate of 19.51°C/Ma, and its rapid uplift occurred in 106–103.95 Ma and 20–0.0 Ma at a rate of 1.06 mm/a and 0.15 mm/a respectively. The Sihetang granite-gneiss uplifted rapidly since 13 Ma at an average rate of 0.256 mm/a. The Badaling granite uplifted rapidly since 6 Ma at an average rate of 0.556 mm/a. The Cenozoic uplift of the Yanshan Mountains can be well correlated to the rifting process of the surrounding basins.