Raw water temperature can fluctuate significantly throughout the year,with peaks above 30℃in summer and below 15℃in winter.Traditional desalination systems(e.g.,reverse osmosis,RO)face challenges under these varying...Raw water temperature can fluctuate significantly throughout the year,with peaks above 30℃in summer and below 15℃in winter.Traditional desalination systems(e.g.,reverse osmosis,RO)face challenges under these varying temperature conditions.Specifically,while the RO system performs well under high temperatures,its efficiency decreases sharply at lower temperatures.Membrane capacitive deionization(MCDI)is considered as an emergent and promising technology for brackish water desalination.While plenty of studies have been devoted to investigating the impacts of raw water properties(e.g.,salinity,coexisting ions,and natural organic matter)on MCDI performance,the role of water temperatures during the desalination remains under-explored.In this study,we first tested and determined the optimized MCDI operation parameters,such as the cell voltage and feedwater flow rate.Key findings showed that MCDI’s salt removal efficiency remains unaffected by feedwater temperature fluctuations.However,as feedwater temperature increases from 15℃to 40℃,the specific energy consumption for desalination slightly rises by 16.3%,and current efficiency drops by 14.1%.Compared to RO systems,the resilience of MCDI to temperature fluctuations makes it a preferable choice for brackish water treatment in areas with a large temperature difference.展开更多
Using multi-directional forging temperature as the independent variable and adopting the dual-mode phase field crystal model,the nucleation modes,reaction mechanisms,and interactions between grain boundaries and dislo...Using multi-directional forging temperature as the independent variable and adopting the dual-mode phase field crystal model,the nucleation modes,reaction mechanisms,and interactions between grain boundaries and dislocations at different temperatures were investigated.Results show that a mapping relationship between process parameters and grain refinement/coarsening is established,and the optimal processing temperature coefficient is 0.23.Compared with the cases with processing temperature coefficient of 0.19,0.20,0.21,0.25,and 0.27,the refinement effect increases by 256.0%,146.0%,113.0%,6.7%,and 52.4%,respectively.Excessively high temperatures lead to grain coarsening due to dislocation annihilation,and the application of strain can reduce the actual melting point of materials.Even if the processing temperature does not exceed the theoretical melting point,remelting and crystallization may still occur,resulting in an overburning phenomenon that reduces internal defects and increases overall grain size.This research is of great significance for the actual forging process design.展开更多
To address the challenges of complex metallic film coating processes and low integration in single-parameter detection for existing photonic crystal fiber surface plasmon resonance(PCF-SPR)sensors,a dual-parameter sen...To address the challenges of complex metallic film coating processes and low integration in single-parameter detection for existing photonic crystal fiber surface plasmon resonance(PCF-SPR)sensors,a dual-parameter sensor based on gold nanowire-integrated bias-core PCF-SPR is proposed.Unlike conventional in-hole coatings or metallic film structures,the gold nanowires are directly attached to the fiber cladding via chemical vapor deposition(CVD),eliminating uneven coating issues and significantly simplifying fabrica-tion.By optimizing the asymmetric bias-core fiber structure and leveraging the strong localized field en-hancement of gold nanowires,the sensor achieves high-sensitivity synchronous detection of temperature(25−60℃)and refractive index(1.31−1.40)in dual-polarization modes.The simulation results demonstrate that the x-polarization mode can achieve 1.31−1.40 refractive index detection with maximum wavelength sensitivity and amplitude sensitivity of 14800 nm/RIU and−1724.25 RIU^(−1),and maximum refractive index resolution of 6.75×10^(−6)RIU.The y-polarization mode achieves refractive index detection range of 1.34−1.40,and the maximum wavelength sensitivity and amplitude sensitivity are 28400 nm/RIU and−1298.93 RIU^(−1),and the maximum refractive index resolution is 3.52×10^(−6)RIU.For temperature sensing,the sensor exhibits a wavelength sensitivity of 7.8 nm/℃and a high resolution of 1.38×10^(−6)℃over the range of 25−60℃.This design synergizes gold nanowires and the bias-core architecture to simplify fabrication while enabling multi-parameter detection.The proposed sensor offers new insights for integrated applications in biochemical mon-itoring,environmental sensing,and related fields.展开更多
Platinum group metals have high melting points,strong corrosion resistance,stable chemical properties,and low oxygen permeability in high-temperature oxygen-containing environments.As thermal protective coating materi...Platinum group metals have high melting points,strong corrosion resistance,stable chemical properties,and low oxygen permeability in high-temperature oxygen-containing environments.As thermal protective coating materials,they have gained essential applications in the aerospace field and have excellent prospects for application in frontier military fields,such as protecting hot-end components of hypersonic aircraft.This research reviewed the latest research progress of platinum group metal coatings with hightemperature oxidation resistance,including coating preparation techniques,oxidation failure,and alloying modification.The leading preparation techniques of current platinum group metal coatings were discussed,as well as the advantages and disadvantages of various existing preparation techniques.Besides,the intrinsic properties,failure forms,and failure mechanisms of coatings of single platinum group metal in high-temperature oxygen-containing environments were analyzed.On this basis,the necessity,main methods,and main achievements of alloying modification of platinum group metals were summarized.Finally,the future development of platinum group coatings with high-temperature oxidation resistance was discussed and prospected.展开更多
Lin Wei is a hiking enthusiast.At six o'clock on the last Saturday morning,the temperature at the foot of the mountain was only 2℃,so she put on her thickest fleece jacket.However,after only half an hour of climb...Lin Wei is a hiking enthusiast.At six o'clock on the last Saturday morning,the temperature at the foot of the mountain was only 2℃,so she put on her thickest fleece jacket.However,after only half an hour of climbing,the heat left her drenched in sweat,making her feel very cold.By midday,the temperature was approaching 20℃,and her heavy jacket had to be tied around her waist,becoming a burden during her hike.This outdoor adventure allowed her to appreciate the beautiful scenery,but also subjected her to repeated changes in temperature.展开更多
In recent years,the research on superconductivity in one-dimensional(1D)materials has been attracting increasing attention due to its potential applications in low-dimensional nanodevices.However,the critical temperat...In recent years,the research on superconductivity in one-dimensional(1D)materials has been attracting increasing attention due to its potential applications in low-dimensional nanodevices.However,the critical temperature(T_(c))of 1D superconductors is low.In this work,we theoretically investigate the possible high T_(c) superconductivity of(5,5)carbon nanotube(CNT).The pristine(5,5)CNT is a Dirac semimetal and can be modulated into a semiconductor by full hydrogenation.Interestingly,by further hole doping,it can be regulated into a metallic state with the sp^(3)-hybridized σ electrons metalized,and a giant Kohn anomaly appears in the optical phonons.The two factors together enhance the electron–phonon coupling,and lead to high-T_(c) superconductivity.When the hole doping concentration of hydrogenated-(5,5)CNT is 2.5 hole/cell,the calculated T_(c) is 82.3 K,exceeding the boiling point of liquid nitrogen.Therefore,the predicted hole-doped hydrogenated-(5,5)CNT provides a new platform for 1D high-T_(c) superconductivity and may have potential applications in 1D nanodevices.展开更多
Spikelet filling characteristics in early-season rice in southern China may be distinctive due to its exposure to high temperatures during the ripening period.However,limited information is currently available on thes...Spikelet filling characteristics in early-season rice in southern China may be distinctive due to its exposure to high temperatures during the ripening period.However,limited information is currently available on these characteristics.This study aimed to characterize spikelet filling in early-season rice and identify the key factors contributing to its improvement.Field experiments were conducted over two years(2021 and 2022)to mainly investigate the proportions of fully-filled,partially-filled,and empty spikelets,along with the biomass-fertilized spikelet ratio and harvest index,in 11 early-season rice varieties.The results revealed significant varietal variation in spikelet filling,with the proportion of fully-filled spikelets ranging from 60.6%to 81.1%in 2021 and from 66.3%to 79.2%in 2022.Among the 11 varieties,Liangyou 42,Lingliangyou 942,and Liangyou 287 exhibited relatively superior performance in spikelet filling.Linear regression revealed that,although a significant negative relationship existed between the proportion of fully-filled spikelets and both partially-filled and empty spikelets,the relationship with partially-filled spikelets was stronger.Additionally,the proportion of fully-filled spikelets showed a significant positive relationship with the harvest index but not with the biomass-fertilized spikelet ratio.These findings indicate that increasing the harvest index and reducing the occurrence of partially-filled grains are essential strategies for improving spikelet filling in early-season rice.展开更多
Prolonged exposure to n-butanol, a common hazardous volatile organic compound(VOC) in the environment, can lead to a broad range of adverse health effects. Therefore, detecting n-butanol safely and efficiently at low ...Prolonged exposure to n-butanol, a common hazardous volatile organic compound(VOC) in the environment, can lead to a broad range of adverse health effects. Therefore, detecting n-butanol safely and efficiently at low concentrations becomes critical for both environmental monitoring and human health. In this study, a novel Eu/Ce-codoped MOF-ZnO gas sensor was developed for the sensitive detection of n-butanol gas under ultraviolet activation at ambient temperature. A series of Eu/Ce-ZnO nanomaterials were synthesized via a simple co-precipitation route, by carefully designing the varied mass ratios of Eu and Ce incorporated into pristine ZnO derived from MOF precursors. The gas testing results revealed that introducing an appropriate amount of Eu and Ce would enlarge the specific surface area and enrich the oxygen vacancy content compared to pristine MOF-ZnO. Upon UV irradiation, the 0.03 wt% Eu 0.04 wt% Ce-ZnO sensor achieved a superior response of 611 for100 ppm n-butanol at room temperature, 15.28 times higher than that of pristine MOF-ZnO(40). Furthermore, the sensor presented rapid response/recovery times(15 s/28 s) and excellent selectivity. The above contributions pave the way for the promising development of highly sensitive, ultraviolet-enhanced gas sensors for ambient temperature detection of VOCs.展开更多
When the operating temperature of a solid oxide electrolysis cell(SOEC)is lower than the outlet temperature of a nuclear reactor,the reactor can be directly coupled with the SOEC as a high-temperature heat source.Howe...When the operating temperature of a solid oxide electrolysis cell(SOEC)is lower than the outlet temperature of a nuclear reactor,the reactor can be directly coupled with the SOEC as a high-temperature heat source.However,the key to the efficiency and return on investment of this hybrid energy system lies in the expected lifetime of the SOEC.This study assessed Ni-YSZ|YSZ|GDC|LSC fuel electrode support cells’long-term stability during electrolysis at 650℃with a current density of−0.5Acm^(−2)over 1818 h.The average voltage degradation rate of 2.63%kh^(−1)unfolded in two phases:an initial rapid decay(90 to 1120 h at 3.58%kh^(−1))and a stable decay(1120 to 1818 h at 2.14%kh^(−1)),emphasizing SOECs’probability coupling with nuclear reactors at 650℃.Post-1818-hour electrolysis revealed nickel particle formation associated with Ni(OH)_(x)diffusion and re-deposition,alongside a strontium-containing layer causing interface cracking.Despite minimal strontium segregation in the EDS,XPS data indicated surface segregation of Sr.This study provides crucial insights into prolonged SOEC operation,highlighting both its potential and challenges.展开更多
With the development of electronic technologies,piezoresistive sensors have attracted increasing attention.Among them,aerogels with high elasticity,as a type of three-dimensional porous material,are widely used in the...With the development of electronic technologies,piezoresistive sensors have attracted increasing attention.Among them,aerogels with high elasticity,as a type of three-dimensional porous material,are widely used in the field of piezoresistive sensors.Nowadays,with the extension of science and technology areas,fields involving low-temperature environments have emerged,which has led to an increasing demand for piezoresistive sensors that can serve at cryogenic temperatures.However,most studies on aerogels have only focused on their sensing performance at room temperature,and there is a lack of research on aerogel sensors that can work at low temperatures.In this work,piezoresistive sensors based on cotton fibers were proposed for applications at 77 K.As one of the most important natural polymers,cotton fibers have the ability to maintain elasticity at very low temperatures.Cotton fiber-based aerogels with high elasticity and cyclic stability were obtained by controlling the freeze-casting parameters and size distribution of cotton fibers,and they showed excellent pressure sensing properties,including a wide sensing range and remarkable long-term stability.This study bridges the gap in cryogenic sensing materials and provides insights into microstructure-property relationships,advancing applications in aerospace and cryogenic engineering.展开更多
Following over 20 years of research,a direct measurement of the QGP temperature has been achieved at Relativistic Heavy-Ion Collider(RHIC),free from the blue-shift effect and contamination from strong interactions.Thi...Following over 20 years of research,a direct measurement of the QGP temperature has been achieved at Relativistic Heavy-Ion Collider(RHIC),free from the blue-shift effect and contamination from strong interactions.This viewpoint discusses a recent measurement of the QGP temperature at different stages at the Solenoidal Tracker at RHIC(STAR),which used e^(+)e^(-)pairs as penetrating probes.展开更多
This investigation utilizes non-equilibrium molecular dynamics(NEMD)simulations to explore shockinduced spallation in single-crystal tantalumacross shock velocities of 0.75–4 km/s and initial temperatures from300 to ...This investigation utilizes non-equilibrium molecular dynamics(NEMD)simulations to explore shockinduced spallation in single-crystal tantalumacross shock velocities of 0.75–4 km/s and initial temperatures from300 to 2000 K.Two spallation modes emerge:classical spallation for shock velocity below 1.5 km/s,with solid-state reversible Body-Centered Cubic(BCC)to Face-Centered Cubic(FCC)orHexagonal Close-Packed(HCP)phase transformations and discrete void nucleation-coalescence;micro-spallation for shock velocity above 3.0 km/s,featuring complete shock-induced melting and fragmentation,with a transitional regime(2.0-2.5 km/s)of partial melting.Spall strength decreases monotonically with temperature due to thermal softening.Elevated temperatures delay void nucleation but increase density,expanding spall regions and enhancing structural disorder with reduced BCC recovery.For microspallation,melting exacerbates damage,causing smaller voids and intensified atomic ejection,which increases with temperature.Free surface velocity profiles indicate damage:in classical spallation,first drop marks nucleation,and pullback signals spall layers.In micro-spallation,the first drop is irrelevant,but remains valid.Temperature delays pullback signals and weakens Hugoniot Elastic Limit.This study clarifies temperature-shock coupling in Ta spallation,aiding failure prediction in high-temperature shock environments.展开更多
Biological invasion is a pressing environmental and ecological challenge worldwide.Cabomba caroliniana(C.caroliniana),a submerged macrophyte native to South America,is listed as a high-priority invasive species in sev...Biological invasion is a pressing environmental and ecological challenge worldwide.Cabomba caroliniana(C.caroliniana),a submerged macrophyte native to South America,is listed as a high-priority invasive species in several countries.It is critical to understand how water temperature influences its invasiveness for effective management.However,research on the effects of water temperature on C.caroliniana the growth is limited.This study used controlled experiments to examine how water temperature(5-30℃)affects the morphological,physiological,photosynthetic,and stoichiometric traits of C.caroliniana.The results showed that broad water temperature tolerance of C.caroliniana significantly impacts its reproductive capacity and invasive potential.At 5-10℃,cold stress induced carotenoid synthesis and total organic carbon accumulation,enabling adaptation to low temperatures.However,C.caroliniana grew slowly,as its root development was limited,and its invasiveness remained low.At 20-30℃,increased chlorophyll synthesis and enhanced resource-use efficiency supported rapid growth,including more branches,leading to high invasion and dispersal potential.Thus,C.caroliniana exhibited strong colonization and spread quickly in tropical and subtropical waters(>20℃).In temperate zones,populations can be established during summer(20-25℃)and survive winter hrough cold adaptation.We recommended prioritizing control measures during warm seasons(20-30℃)to disrupt propagule dispersal,alongside early monitoring in temperate waters to inhibit ecological invasion.展开更多
The demand for sensors capable of operating in extreme environment of the fields,such as aerospace vehicles,aeroengines and fire protection,is rapidly increasing.However,developing flexible ceramic fibrous pressure se...The demand for sensors capable of operating in extreme environment of the fields,such as aerospace vehicles,aeroengines and fire protection,is rapidly increasing.However,developing flexible ceramic fibrous pressure sensors that combine high temperature stability with robust mechanical properties remains a significant challenge.Herein,through precise multi-scale process control,high-strength(2.1 MPa)TiC-SiC flexible fibrous membrane is successfully fabricated.The membrane exhibits exceptional thermal resistance(2000℃)and long–term thermal stability(1800℃ for 5 h)in the inert atmosphere.Meanwhile,the TiC-SiC fibrous membrane shows excellent oxidation resistance and still achieves strength of 1.8 MPa after being oxidized at 1200℃ for 1 h in air.Remarkably,TiC-SiC fibrous membrane withstands a load of approximately 1400 times its own weight and the ablation of butane flame(~1300℃)for at least 1 h without breaking.Notably,after heat treatment at 1800℃ for 5 h in an argon atmosphere,the TiC-SiC fibrous membrane even sustains pressure–sensing performance for up to 300 cycles.The membrane exhibits stable resistivity up to 900℃ and shows sensing stability under butane flame.The results of this work provide an effective and feasible solution to fill the research gap of flexible fibrous sensors for extreme environments.展开更多
The glass transition temperature(T_(g))of styrene-butadiene rubber(SBR)is a key parameter determining its low-temperature flexibility and processing performance.Accurate prediction of T_(g)is crucial formaterial desig...The glass transition temperature(T_(g))of styrene-butadiene rubber(SBR)is a key parameter determining its low-temperature flexibility and processing performance.Accurate prediction of T_(g)is crucial formaterial design and application optimisation.Addressing the limitations of traditional experimental measurements and theoretical models in terms of efficiency,cost,and accuracy,this study proposes a machine learning prediction framework that integrates multi-model ensemble and Bayesian optimization by constructing a multi-component feature dataset and algorithm optimization strategy.Based on the constructed high-quality dataset containing 96 SBR samples,ninemachine learning models were employed to predict the T_(g)of SBR and compare their prediction performance.Ultimately,aGPR-XGBoost mixed model was constructed through model ensemble,achieving high-precision prediction with R^(2)values greater than 0.9 on both the training and test sets.Further feature attribution and local effect analysis were conducted using feature analysis methods such as SHAP and ALE,revealing the nonlinear influence patterns of various components on T_(g),providing a theoretical basis for SBR formulation design and T_(g)regulation.The machine learning prediction framework established in this study combines high-precision prediction with interpretability,significantly enhancing the prediction performance of the T_(g)of SBR.It offers an efficient tool for SBR molecular design and holds great potential for promotion and application.展开更多
For red pear,the anthocyanin content is a crucial factor determining the fruit skin color,which affects consumer preferences.Low overnight temperatures promote anthocyanin accumulation,but the molecular mechanism resp...For red pear,the anthocyanin content is a crucial factor determining the fruit skin color,which affects consumer preferences.Low overnight temperatures promote anthocyanin accumulation,but the molecular mechanism responsible is unclear.In this study,‘Hongzaosu’pear(Pyrus pyrifolia×Pyrus communis)fruit were treated with a low nighttime temperature(LNT,16℃)or a warm nighttime temperature(WNT,26℃),with sampling conducted within two diurnal cycles.The results showed that LNT promoted anthocyanin accumulation in the fruit skin.The structural anthocyanin biosynthetic genes PpCHS,PpF3H,and PpUFGT exhibited a rhythmic increase in expression at night under LNT.To examine the underlying mechanism,RNA sequencing was conducted using pear calli exposed to LNT and WNT for different durations(24,48,72,or 96 h).Transcriptome analysis revealed 285 differentially expressed genes(DEGs)common to all pairwise comparisons of LNT-and WNT-treated calli of‘Clapp's Favorite’(P.communis)at the sampling time points.KEGG pathway and gene ontology enrichment analyses indicated that the common DEGs were enriched in secondary metabolic processes and phenylpropanoid metabolic processes,which are associated with anthocyanin biosynthesis.The transcription factor PpCDF5,which was responsive to LNT,was selected for further study.Dual-luciferase assays showed that PpCDF5 activated the transcription of anthocyanin biosynthetic genes PpMYB10,PpCHS,PpF3H,PpDFR,PpANS,and PpUFGT.The yeast one-hybrid and EMSA assays demonstrated that PpCDF5 directly binds to the PpF3H promoter,which contains an AAAG motif.Overexpression of PpCDF5 in pear calli and transient overexpression in pear fruit both increased anthocyanin accumulation.The results indicate that PpCDF5 is involved in LNT-induced anthocyanin biosynthesis in pear fruit and provide insights into the molecular regulation of commercial fruit coloration.展开更多
Temperature stability is essential for the precision of flexible sensors.However,constrained by the composite principle of heterogeneous materials,the existing self-compensating methods encounter substantial challenge...Temperature stability is essential for the precision of flexible sensors.However,constrained by the composite principle of heterogeneous materials,the existing self-compensating methods encounter substantial challenges.To tackle this,high-entropy alloy nanofibers were utilized to construct a flexible strain sensor with inherent temperature stability.This approach leverages the electrohydrodynamic direct writing;a precursor conductive network was established through the electrospinning of a high-entropy alloy acetate and polyvinylidene difluoride solution blend.Subsequently,annealing treatment facilitated metallization,resulting in the synergistic preservation of polymer stretchability and the low temperature coefficient of resistance properties of high-entropy alloys inside the nanofibers.The test results demonstrate that the high-entropy alloys flexible strain sensor exhibits a remarkably low temperature coefficient of resistance(45.59 ppm K^(-1))across the range of-10 to 70℃,a sensitivity coefficient GF of 1.12 with a 50%strain range,and a response time of 310 ms.After 6000 stretching cycles,no baseline drift or failure occurred,indicating excellent cyclic stability.Furthermore,the outstanding temperature stability of the sensor was validated through wearable application and robotic hands strain sensing conducted under varied environment temperatures.This work provides a viable design pathway for developing flexible sensors with an inherently low temperature coefficient of resistance.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52370090,52300016)China Postdoctoral Science Foundation(Nos.2023M733379,2024M753122).
文摘Raw water temperature can fluctuate significantly throughout the year,with peaks above 30℃in summer and below 15℃in winter.Traditional desalination systems(e.g.,reverse osmosis,RO)face challenges under these varying temperature conditions.Specifically,while the RO system performs well under high temperatures,its efficiency decreases sharply at lower temperatures.Membrane capacitive deionization(MCDI)is considered as an emergent and promising technology for brackish water desalination.While plenty of studies have been devoted to investigating the impacts of raw water properties(e.g.,salinity,coexisting ions,and natural organic matter)on MCDI performance,the role of water temperatures during the desalination remains under-explored.In this study,we first tested and determined the optimized MCDI operation parameters,such as the cell voltage and feedwater flow rate.Key findings showed that MCDI’s salt removal efficiency remains unaffected by feedwater temperature fluctuations.However,as feedwater temperature increases from 15℃to 40℃,the specific energy consumption for desalination slightly rises by 16.3%,and current efficiency drops by 14.1%.Compared to RO systems,the resilience of MCDI to temperature fluctuations makes it a preferable choice for brackish water treatment in areas with a large temperature difference.
基金National Natural Science Foundation of China(52375394,52275390,U23A20628,52305429)Major Project of Science and Technology in Shanxi(202301050201004)Natural Science Foundation of Shanxi Province(202403021222132)。
文摘Using multi-directional forging temperature as the independent variable and adopting the dual-mode phase field crystal model,the nucleation modes,reaction mechanisms,and interactions between grain boundaries and dislocations at different temperatures were investigated.Results show that a mapping relationship between process parameters and grain refinement/coarsening is established,and the optimal processing temperature coefficient is 0.23.Compared with the cases with processing temperature coefficient of 0.19,0.20,0.21,0.25,and 0.27,the refinement effect increases by 256.0%,146.0%,113.0%,6.7%,and 52.4%,respectively.Excessively high temperatures lead to grain coarsening due to dislocation annihilation,and the application of strain can reduce the actual melting point of materials.Even if the processing temperature does not exceed the theoretical melting point,remelting and crystallization may still occur,resulting in an overburning phenomenon that reduces internal defects and increases overall grain size.This research is of great significance for the actual forging process design.
文摘To address the challenges of complex metallic film coating processes and low integration in single-parameter detection for existing photonic crystal fiber surface plasmon resonance(PCF-SPR)sensors,a dual-parameter sensor based on gold nanowire-integrated bias-core PCF-SPR is proposed.Unlike conventional in-hole coatings or metallic film structures,the gold nanowires are directly attached to the fiber cladding via chemical vapor deposition(CVD),eliminating uneven coating issues and significantly simplifying fabrica-tion.By optimizing the asymmetric bias-core fiber structure and leveraging the strong localized field en-hancement of gold nanowires,the sensor achieves high-sensitivity synchronous detection of temperature(25−60℃)and refractive index(1.31−1.40)in dual-polarization modes.The simulation results demonstrate that the x-polarization mode can achieve 1.31−1.40 refractive index detection with maximum wavelength sensitivity and amplitude sensitivity of 14800 nm/RIU and−1724.25 RIU^(−1),and maximum refractive index resolution of 6.75×10^(−6)RIU.The y-polarization mode achieves refractive index detection range of 1.34−1.40,and the maximum wavelength sensitivity and amplitude sensitivity are 28400 nm/RIU and−1298.93 RIU^(−1),and the maximum refractive index resolution is 3.52×10^(−6)RIU.For temperature sensing,the sensor exhibits a wavelength sensitivity of 7.8 nm/℃and a high resolution of 1.38×10^(−6)℃over the range of 25−60℃.This design synergizes gold nanowires and the bias-core architecture to simplify fabrication while enabling multi-parameter detection.The proposed sensor offers new insights for integrated applications in biochemical mon-itoring,environmental sensing,and related fields.
文摘Platinum group metals have high melting points,strong corrosion resistance,stable chemical properties,and low oxygen permeability in high-temperature oxygen-containing environments.As thermal protective coating materials,they have gained essential applications in the aerospace field and have excellent prospects for application in frontier military fields,such as protecting hot-end components of hypersonic aircraft.This research reviewed the latest research progress of platinum group metal coatings with hightemperature oxidation resistance,including coating preparation techniques,oxidation failure,and alloying modification.The leading preparation techniques of current platinum group metal coatings were discussed,as well as the advantages and disadvantages of various existing preparation techniques.Besides,the intrinsic properties,failure forms,and failure mechanisms of coatings of single platinum group metal in high-temperature oxygen-containing environments were analyzed.On this basis,the necessity,main methods,and main achievements of alloying modification of platinum group metals were summarized.Finally,the future development of platinum group coatings with high-temperature oxidation resistance was discussed and prospected.
文摘Lin Wei is a hiking enthusiast.At six o'clock on the last Saturday morning,the temperature at the foot of the mountain was only 2℃,so she put on her thickest fleece jacket.However,after only half an hour of climbing,the heat left her drenched in sweat,making her feel very cold.By midday,the temperature was approaching 20℃,and her heavy jacket had to be tied around her waist,becoming a burden during her hike.This outdoor adventure allowed her to appreciate the beautiful scenery,but also subjected her to repeated changes in temperature.
基金supported by the National Natural Science Foundation of China (Grant Nos.12074213 and 11574108)the Major Basic Program of Natural Science Foundation of Shandong Province (Grant No.ZR2021ZD01)the Natural Science Foundation of Shandong Province (Grant No.ZR2023MA082)。
文摘In recent years,the research on superconductivity in one-dimensional(1D)materials has been attracting increasing attention due to its potential applications in low-dimensional nanodevices.However,the critical temperature(T_(c))of 1D superconductors is low.In this work,we theoretically investigate the possible high T_(c) superconductivity of(5,5)carbon nanotube(CNT).The pristine(5,5)CNT is a Dirac semimetal and can be modulated into a semiconductor by full hydrogenation.Interestingly,by further hole doping,it can be regulated into a metallic state with the sp^(3)-hybridized σ electrons metalized,and a giant Kohn anomaly appears in the optical phonons.The two factors together enhance the electron–phonon coupling,and lead to high-T_(c) superconductivity.When the hole doping concentration of hydrogenated-(5,5)CNT is 2.5 hole/cell,the calculated T_(c) is 82.3 K,exceeding the boiling point of liquid nitrogen.Therefore,the predicted hole-doped hydrogenated-(5,5)CNT provides a new platform for 1D high-T_(c) superconductivity and may have potential applications in 1D nanodevices.
基金funded by the Earmarked Fund for China Agriculture Research System,grant number CARS-01-33.
文摘Spikelet filling characteristics in early-season rice in southern China may be distinctive due to its exposure to high temperatures during the ripening period.However,limited information is currently available on these characteristics.This study aimed to characterize spikelet filling in early-season rice and identify the key factors contributing to its improvement.Field experiments were conducted over two years(2021 and 2022)to mainly investigate the proportions of fully-filled,partially-filled,and empty spikelets,along with the biomass-fertilized spikelet ratio and harvest index,in 11 early-season rice varieties.The results revealed significant varietal variation in spikelet filling,with the proportion of fully-filled spikelets ranging from 60.6%to 81.1%in 2021 and from 66.3%to 79.2%in 2022.Among the 11 varieties,Liangyou 42,Lingliangyou 942,and Liangyou 287 exhibited relatively superior performance in spikelet filling.Linear regression revealed that,although a significant negative relationship existed between the proportion of fully-filled spikelets and both partially-filled and empty spikelets,the relationship with partially-filled spikelets was stronger.Additionally,the proportion of fully-filled spikelets showed a significant positive relationship with the harvest index but not with the biomass-fertilized spikelet ratio.These findings indicate that increasing the harvest index and reducing the occurrence of partially-filled grains are essential strategies for improving spikelet filling in early-season rice.
基金supported by the National Natural Science Foundation of China (Grant No. 12304467)the China Postdoctoral Science Foundation (Grant No. 2023M732175)。
文摘Prolonged exposure to n-butanol, a common hazardous volatile organic compound(VOC) in the environment, can lead to a broad range of adverse health effects. Therefore, detecting n-butanol safely and efficiently at low concentrations becomes critical for both environmental monitoring and human health. In this study, a novel Eu/Ce-codoped MOF-ZnO gas sensor was developed for the sensitive detection of n-butanol gas under ultraviolet activation at ambient temperature. A series of Eu/Ce-ZnO nanomaterials were synthesized via a simple co-precipitation route, by carefully designing the varied mass ratios of Eu and Ce incorporated into pristine ZnO derived from MOF precursors. The gas testing results revealed that introducing an appropriate amount of Eu and Ce would enlarge the specific surface area and enrich the oxygen vacancy content compared to pristine MOF-ZnO. Upon UV irradiation, the 0.03 wt% Eu 0.04 wt% Ce-ZnO sensor achieved a superior response of 611 for100 ppm n-butanol at room temperature, 15.28 times higher than that of pristine MOF-ZnO(40). Furthermore, the sensor presented rapid response/recovery times(15 s/28 s) and excellent selectivity. The above contributions pave the way for the promising development of highly sensitive, ultraviolet-enhanced gas sensors for ambient temperature detection of VOCs.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA0400000)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2021253)+1 种基金the Major Science and Technology Projects of China National Offshore Oil Corporation Limited during the 14th Five Year Plan(No.KJGG-2022-12-CCUS-030500)the Photon Science Center for Carbon Neutrality of Chinese Academy of Science.
文摘When the operating temperature of a solid oxide electrolysis cell(SOEC)is lower than the outlet temperature of a nuclear reactor,the reactor can be directly coupled with the SOEC as a high-temperature heat source.However,the key to the efficiency and return on investment of this hybrid energy system lies in the expected lifetime of the SOEC.This study assessed Ni-YSZ|YSZ|GDC|LSC fuel electrode support cells’long-term stability during electrolysis at 650℃with a current density of−0.5Acm^(−2)over 1818 h.The average voltage degradation rate of 2.63%kh^(−1)unfolded in two phases:an initial rapid decay(90 to 1120 h at 3.58%kh^(−1))and a stable decay(1120 to 1818 h at 2.14%kh^(−1)),emphasizing SOECs’probability coupling with nuclear reactors at 650℃.Post-1818-hour electrolysis revealed nickel particle formation associated with Ni(OH)_(x)diffusion and re-deposition,alongside a strontium-containing layer causing interface cracking.Despite minimal strontium segregation in the EDS,XPS data indicated surface segregation of Sr.This study provides crucial insights into prolonged SOEC operation,highlighting both its potential and challenges.
基金financially supported by the National Natural Science Foundation of China(No.52073294)National Key R&D Program of China(No.2021YFB4000700)+1 种基金Project of Stable Support for Youth Team in Basic Research Field of the Chinese Academy of Sciences,China(No.YSBR-017)The authors are highly grateful to Mr.Fan-Ming Zhao for Cryogenic Mechanical Testing.
文摘With the development of electronic technologies,piezoresistive sensors have attracted increasing attention.Among them,aerogels with high elasticity,as a type of three-dimensional porous material,are widely used in the field of piezoresistive sensors.Nowadays,with the extension of science and technology areas,fields involving low-temperature environments have emerged,which has led to an increasing demand for piezoresistive sensors that can serve at cryogenic temperatures.However,most studies on aerogels have only focused on their sensing performance at room temperature,and there is a lack of research on aerogel sensors that can work at low temperatures.In this work,piezoresistive sensors based on cotton fibers were proposed for applications at 77 K.As one of the most important natural polymers,cotton fibers have the ability to maintain elasticity at very low temperatures.Cotton fiber-based aerogels with high elasticity and cyclic stability were obtained by controlling the freeze-casting parameters and size distribution of cotton fibers,and they showed excellent pressure sensing properties,including a wide sensing range and remarkable long-term stability.This study bridges the gap in cryogenic sensing materials and provides insights into microstructure-property relationships,advancing applications in aerospace and cryogenic engineering.
文摘Following over 20 years of research,a direct measurement of the QGP temperature has been achieved at Relativistic Heavy-Ion Collider(RHIC),free from the blue-shift effect and contamination from strong interactions.This viewpoint discusses a recent measurement of the QGP temperature at different stages at the Solenoidal Tracker at RHIC(STAR),which used e^(+)e^(-)pairs as penetrating probes.
基金funded by the Changsha Municipal Natural Science Foundation(Grant No.kq2402024)Chengdu Polytechnic Scientific Research Platform(23KYPT01).
文摘This investigation utilizes non-equilibrium molecular dynamics(NEMD)simulations to explore shockinduced spallation in single-crystal tantalumacross shock velocities of 0.75–4 km/s and initial temperatures from300 to 2000 K.Two spallation modes emerge:classical spallation for shock velocity below 1.5 km/s,with solid-state reversible Body-Centered Cubic(BCC)to Face-Centered Cubic(FCC)orHexagonal Close-Packed(HCP)phase transformations and discrete void nucleation-coalescence;micro-spallation for shock velocity above 3.0 km/s,featuring complete shock-induced melting and fragmentation,with a transitional regime(2.0-2.5 km/s)of partial melting.Spall strength decreases monotonically with temperature due to thermal softening.Elevated temperatures delay void nucleation but increase density,expanding spall regions and enhancing structural disorder with reduced BCC recovery.For microspallation,melting exacerbates damage,causing smaller voids and intensified atomic ejection,which increases with temperature.Free surface velocity profiles indicate damage:in classical spallation,first drop marks nucleation,and pullback signals spall layers.In micro-spallation,the first drop is irrelevant,but remains valid.Temperature delays pullback signals and weakens Hugoniot Elastic Limit.This study clarifies temperature-shock coupling in Ta spallation,aiding failure prediction in high-temperature shock environments.
基金funded by the Open Project Funding of Key Laboratory of Intelligent Health Perception and Ecological Restoration of Rivers and Lakes,Ministry of Education,Hubei University of Technology(HGKFYBP03)the Open Foundation of Resource-exhausted City Transformation and Development Research Center(Hubei Normal University)(KF2024Y07)the College Students'Innovative Entrepreneurial Training Plan Program(S202410513099,202410513009).
文摘Biological invasion is a pressing environmental and ecological challenge worldwide.Cabomba caroliniana(C.caroliniana),a submerged macrophyte native to South America,is listed as a high-priority invasive species in several countries.It is critical to understand how water temperature influences its invasiveness for effective management.However,research on the effects of water temperature on C.caroliniana the growth is limited.This study used controlled experiments to examine how water temperature(5-30℃)affects the morphological,physiological,photosynthetic,and stoichiometric traits of C.caroliniana.The results showed that broad water temperature tolerance of C.caroliniana significantly impacts its reproductive capacity and invasive potential.At 5-10℃,cold stress induced carotenoid synthesis and total organic carbon accumulation,enabling adaptation to low temperatures.However,C.caroliniana grew slowly,as its root development was limited,and its invasiveness remained low.At 20-30℃,increased chlorophyll synthesis and enhanced resource-use efficiency supported rapid growth,including more branches,leading to high invasion and dispersal potential.Thus,C.caroliniana exhibited strong colonization and spread quickly in tropical and subtropical waters(>20℃).In temperate zones,populations can be established during summer(20-25℃)and survive winter hrough cold adaptation.We recommended prioritizing control measures during warm seasons(20-30℃)to disrupt propagule dispersal,alongside early monitoring in temperate waters to inhibit ecological invasion.
基金supported by National Natural Science Foundation of China(Grant No.52272100)the Fund of Science and Technology on Advanced Ceramic Fibers and Composites Laboratory(Grant No.WDZC20215250507)the Fund of National Key Laboratory of Nuclear Reactor Technology of Nuclear Power Institute of China(KGSW-0324-0301-08)。
文摘The demand for sensors capable of operating in extreme environment of the fields,such as aerospace vehicles,aeroengines and fire protection,is rapidly increasing.However,developing flexible ceramic fibrous pressure sensors that combine high temperature stability with robust mechanical properties remains a significant challenge.Herein,through precise multi-scale process control,high-strength(2.1 MPa)TiC-SiC flexible fibrous membrane is successfully fabricated.The membrane exhibits exceptional thermal resistance(2000℃)and long–term thermal stability(1800℃ for 5 h)in the inert atmosphere.Meanwhile,the TiC-SiC fibrous membrane shows excellent oxidation resistance and still achieves strength of 1.8 MPa after being oxidized at 1200℃ for 1 h in air.Remarkably,TiC-SiC fibrous membrane withstands a load of approximately 1400 times its own weight and the ablation of butane flame(~1300℃)for at least 1 h without breaking.Notably,after heat treatment at 1800℃ for 5 h in an argon atmosphere,the TiC-SiC fibrous membrane even sustains pressure–sensing performance for up to 300 cycles.The membrane exhibits stable resistivity up to 900℃ and shows sensing stability under butane flame.The results of this work provide an effective and feasible solution to fill the research gap of flexible fibrous sensors for extreme environments.
基金supported by the National Natural Science Foundation of China(grant numbers 52250357 and 52203003).
文摘The glass transition temperature(T_(g))of styrene-butadiene rubber(SBR)is a key parameter determining its low-temperature flexibility and processing performance.Accurate prediction of T_(g)is crucial formaterial design and application optimisation.Addressing the limitations of traditional experimental measurements and theoretical models in terms of efficiency,cost,and accuracy,this study proposes a machine learning prediction framework that integrates multi-model ensemble and Bayesian optimization by constructing a multi-component feature dataset and algorithm optimization strategy.Based on the constructed high-quality dataset containing 96 SBR samples,ninemachine learning models were employed to predict the T_(g)of SBR and compare their prediction performance.Ultimately,aGPR-XGBoost mixed model was constructed through model ensemble,achieving high-precision prediction with R^(2)values greater than 0.9 on both the training and test sets.Further feature attribution and local effect analysis were conducted using feature analysis methods such as SHAP and ALE,revealing the nonlinear influence patterns of various components on T_(g),providing a theoretical basis for SBR formulation design and T_(g)regulation.The machine learning prediction framework established in this study combines high-precision prediction with interpretability,significantly enhancing the prediction performance of the T_(g)of SBR.It offers an efficient tool for SBR molecular design and holds great potential for promotion and application.
基金supported by the National Natural Science Foundation of China(Grant Nos.32072545,32272639 and 32260745)Zhejiang Provincial Natural Science Foundation of China(Grant Nos.LTGN23C150009 and LY22C150003)Zhejiang University Experimental Technology Research Project(Grant No.SYBJS202217).
文摘For red pear,the anthocyanin content is a crucial factor determining the fruit skin color,which affects consumer preferences.Low overnight temperatures promote anthocyanin accumulation,but the molecular mechanism responsible is unclear.In this study,‘Hongzaosu’pear(Pyrus pyrifolia×Pyrus communis)fruit were treated with a low nighttime temperature(LNT,16℃)or a warm nighttime temperature(WNT,26℃),with sampling conducted within two diurnal cycles.The results showed that LNT promoted anthocyanin accumulation in the fruit skin.The structural anthocyanin biosynthetic genes PpCHS,PpF3H,and PpUFGT exhibited a rhythmic increase in expression at night under LNT.To examine the underlying mechanism,RNA sequencing was conducted using pear calli exposed to LNT and WNT for different durations(24,48,72,or 96 h).Transcriptome analysis revealed 285 differentially expressed genes(DEGs)common to all pairwise comparisons of LNT-and WNT-treated calli of‘Clapp's Favorite’(P.communis)at the sampling time points.KEGG pathway and gene ontology enrichment analyses indicated that the common DEGs were enriched in secondary metabolic processes and phenylpropanoid metabolic processes,which are associated with anthocyanin biosynthesis.The transcription factor PpCDF5,which was responsive to LNT,was selected for further study.Dual-luciferase assays showed that PpCDF5 activated the transcription of anthocyanin biosynthetic genes PpMYB10,PpCHS,PpF3H,PpDFR,PpANS,and PpUFGT.The yeast one-hybrid and EMSA assays demonstrated that PpCDF5 directly binds to the PpF3H promoter,which contains an AAAG motif.Overexpression of PpCDF5 in pear calli and transient overexpression in pear fruit both increased anthocyanin accumulation.The results indicate that PpCDF5 is involved in LNT-induced anthocyanin biosynthesis in pear fruit and provide insights into the molecular regulation of commercial fruit coloration.
基金financially supported by National Natural Science Foundation of China(52575458,52405424,52275575)Science and Technology Programme of Fujian Province(2024J010011,2024H0002)。
文摘Temperature stability is essential for the precision of flexible sensors.However,constrained by the composite principle of heterogeneous materials,the existing self-compensating methods encounter substantial challenges.To tackle this,high-entropy alloy nanofibers were utilized to construct a flexible strain sensor with inherent temperature stability.This approach leverages the electrohydrodynamic direct writing;a precursor conductive network was established through the electrospinning of a high-entropy alloy acetate and polyvinylidene difluoride solution blend.Subsequently,annealing treatment facilitated metallization,resulting in the synergistic preservation of polymer stretchability and the low temperature coefficient of resistance properties of high-entropy alloys inside the nanofibers.The test results demonstrate that the high-entropy alloys flexible strain sensor exhibits a remarkably low temperature coefficient of resistance(45.59 ppm K^(-1))across the range of-10 to 70℃,a sensitivity coefficient GF of 1.12 with a 50%strain range,and a response time of 310 ms.After 6000 stretching cycles,no baseline drift or failure occurred,indicating excellent cyclic stability.Furthermore,the outstanding temperature stability of the sensor was validated through wearable application and robotic hands strain sensing conducted under varied environment temperatures.This work provides a viable design pathway for developing flexible sensors with an inherently low temperature coefficient of resistance.
