This study investigates the mechanical properties of Q235B steel through quasi-static tests at both room temperature and elevated temperature.The initial values of the Johnson-Cook model parameters are determined usin...This study investigates the mechanical properties of Q235B steel through quasi-static tests at both room temperature and elevated temperature.The initial values of the Johnson-Cook model parameters are determined using a fitting method.The global response surface algorithm is employed to optimize and calibrate the Johnson-Cook model parameters for Q235B steel under both room temperature and elevated temperature conditions.A simulation model is established at room temperature,and the simulated mechanical performance curves for displacement and stress are monitored.Multiple optimization algorithms are applied to optimize and calibrate the model parameters at room temperature.The global response surface algorithm is identified as the most suitable algorithm for this optimization problem.Sensitivity analysis is conducted to explore the impact of model parameters on the objective function.The analysis indicates that the optimized material model better fits the experimental values,aligning more closely with the actual test results of material strain mechanisms over a wide temperature range.展开更多
Green and sustainable options are needed to ease the current energy and environmental crisis, and alleviate the greenhouse effect and energy shortage. As an alternative carbon–neutral synthetic fuel, ammonia shows gr...Green and sustainable options are needed to ease the current energy and environmental crisis, and alleviate the greenhouse effect and energy shortage. As an alternative carbon–neutral synthetic fuel, ammonia shows great potential due to its high energy density, non-toxic by-products, and mature related infrastructures. However, related practical applications have been severely hampered on ammoniaoxidation due to the high cost of catalysts and immature energy utilization systems. Here, we comprehensively summarized the efforts which have been made in recent years with the aim of providing a deep sight into the development and deficiencies in this territory and trying to establish a simple framework of basic knowledge for researchers. The exploration of mechanism is discussed first and then the relevant catalysts studied in recent years are summarized. Besides, the progress of direct ammonia fuel cells(DAFCs) is also presented and the challenges as well as perspectives on future developments of electrocatalysts for ammonia electro-oxidation and its practical application are provided at the end.展开更多
Lithium-sulfur batteries(LSBs)have a high theoretical capacity,which is considered as one of the most promising high-energy-density secondary batteries due to the double electrons reaction of sulfur.However,the shuttl...Lithium-sulfur batteries(LSBs)have a high theoretical capacity,which is considered as one of the most promising high-energy-density secondary batteries due to the double electrons reaction of sulfur.However,the shuttle effects of lithium polysulfides(Li PSs)and sluggish redox kinetics lead to their materials capacity loss and cycle stability deterioration,which restrains LSBs commercialization.Metallic compounds as additions can improve the electrochemical performance of the Li-S system,through the trap of Li PSs and accelerate the conversion of the soluble Li PSs.Among of them,the iron group elements(Fe,Ni,Co)-based compounds are the promising materials for the LSBs,due to their unique outer electronic structure and its tunable properties,low cost,abundant in the earth,environmental benignity,controllable and scalable prepared,and so on.In this review,we have made a summary for iron-based compounds to capture Li PSs according to lithium bond,sulfur bond and magnetic force.The type of iron-based compound including oxides,sulfides,nitrides,phosphides,carbides,and so on,and we have investigated the electrocatalytic mechanism of these materials.Besides,some improvement strategies are proposed,such as the engineering of the special micro/nanostructure,defect concentrations,band structures,and heterostructures.We hope to shed an in-depth light on the rationally design and fabrication of robust,commercial and stable materials for high-performance LSBs.展开更多
Rationally manipulating surface reconstruction of catalysts for water oxidation,inducing formation and dynamic accumulation of catalytically active centers still face numerous challenges.Herein,the introduction of[Cr(...Rationally manipulating surface reconstruction of catalysts for water oxidation,inducing formation and dynamic accumulation of catalytically active centers still face numerous challenges.Herein,the introduction of[Cr(C_(2)O_(4))_(3)]^(3-)into NiFe LDHs by intercalation engineering to promote surface reconstruction achieves an advanced oxygen evolution reaction(OER)activity.In view of the weak electronegativity of Cr^(3+) in[Cr(C_(2)O_(4))_(3)]^(3-),the intercalation of[Cr(C_(2)O_(4))_(3)]^(3-)is expected to result in an electron-rich structure of Fe sites in NiFe LDHs,and higher valence state of Ni can be formed with the charge transfer between Fe and Ni.The optimized electronic structure of NiFe-[Cr(C_(2)O_(4))_(3)]^(3-)-LDHs with more active Ni^(3+) species and the expedited dynamic generation of Ni^(3+) (Fe)OOH phase during the OER process contributed to its excellent catalytic property,revealed by in situ X-ray absorption spectroscopy,Raman spectroscopy,and quasi-in situ X-ray photoelectron spectroscopy.With the modulated electronic structure of metal sites,NiFe-[Cr(C_(2)O_(4))_(3)]^(3-)-LDHs exhibited promoted OER property with a lower overpotential of 236 mV at the current density of 10 mA cm^(-2).This work illustrates the intercalation of conjugated anion to dynamically construct desired Ni^(3+) sites with the optimal electronic environment for improved OER electrocatalysis.展开更多
Better understanding of electrochemical reaction behaviors of hydrazine electrooxidation at metal phosphides has long been desired and the optimization of reaction kinetics has been proved to be operable.Herein,the de...Better understanding of electrochemical reaction behaviors of hydrazine electrooxidation at metal phosphides has long been desired and the optimization of reaction kinetics has been proved to be operable.Herein,the dehydrogenation kinetics of hydrazine electrooxidation at Ni_(2)P is adjusted by Co as the(Ni_(0.6)Co_(0.4))_(2)P catalyzes HzOR effectively with onset potential of–45 mV and only 113 mV is needed to drive the current density of 50 mA cm^(‒2),showing over 60 mV lower than Ni_(2)P and Co_(2)P.It also delivers the maximum power density of 263.0 mW cm^(-2) for direct hydrazine fuel cell.Detailed experimental results revealed that Co doping not only decreases the adsorption energy of N_(2)H_(4) on Ni sites,lowering the energy barrier for dehydrogenation,but also acts as the active sites in the optimal reaction coordination to boost the reaction kinetics.This work represents a breakthrough in improving the catalytic performance of non‐precious metal electrocatalysts for hydrazine electrooxidation and highlights an energy‐saving electrochemical hydrogen production method.展开更多
The ＂summer prediction barrier＂ （SPB） of SST anomalies （SSTA） over the Kuroshio--Oyashio Extension （KOE） refers to the phenomenon that prediction errors of KOE-SSTA tend to increase rapidly during boreal summe...The ＂summer prediction barrier＂ （SPB） of SST anomalies （SSTA） over the Kuroshio--Oyashio Extension （KOE） refers to the phenomenon that prediction errors of KOE-SSTA tend to increase rapidly during boreal summer, resulting in large prediction uncertainties. The fast error growth associated with the SPB occurs in the mature-to-decaying transition phase, which is usually during the August-September-October （ASO） season, of the KOE-SSTA events to be predicted. Thus, the role of KOE-SSTA evolutionary characteristics in the transition phase in inducing the SPB is explored by performing perfect model predictability experiments in a coupled model, indicating that the SSTA events with larger mature-to-decaying transi- tion rates （Category-l） favor a greater possibility of yielding a more significant SPB than those events with smaller transition rates （Category-2）. The KOE-SSTA events in Category-1 tend to have more significant anomalous Ekman pumping in their transition phase, resulting in larger prediction errors of vertical oceanic temperature advection associated with the SSTA events. Consequently, Category-1 events possess faster error growth and larger prediction errors. In addition, the anomalous Ekman upwelling （downwelling） in the ASO season also causes SSTA cooling （warming）, accelerating the transition rates of warm （cold） KOE-SSTA events. Therefore, the SSTA transition rate and error growth rate are both related with the anomalous Ekman pumping of the SSTA events to be predicted in their transition phase. This may explain why the SSTA events transferring more rapidly from the mature to decaying phase tend to have a greater possibility of yielding a more significant SPB.展开更多
Collective behaviors efficiently impart benefits to a diversity of species ranging from bacteria to humans.Fly larvae tend to cluster and form coordinated digging groups under crowded conditions,yet understanding the ...Collective behaviors efficiently impart benefits to a diversity of species ranging from bacteria to humans.Fly larvae tend to cluster and form coordinated digging groups under crowded conditions,yet understanding the rules governing this behavior is in its infancy.We primarily took advantage of the Drosophila model to investigate cooperative foraging behavior.Here,we report that Drosophila-related species and the black soldier fly have evolved a conserved strategy of cluster digging in food foraging.Subsequently,we investigated relative factors,including larval stage,population density,and food stiffness and quality,that affect the cluster digging behavior.Remarkably,oxygen supply through the posterior breathing spiracles is necessary for the organization of digging clusters.More importantly,we theoretically devise a mathematical model to accurately calculate how the cluster digging behavior expands food resources by diving depth,cross-section area,and food volume.We found that cluster digging behavior approximately increases 2.2 fold depth,1.7-fold cross-section area,and 1.9 fold volume than control groups,respectively.Amplification of food sources significantly facilitates survival,larval development,and reproductive success of Drosophila challenged with competition for limited food resources,thereby conferring trophic benefits to fitness in insects.Overall,our findings highlight that the cluster digging behavior is a pivotal behavior for their adaptation to food scarcity,advancing a better understanding of how this cooperative behavior confers fitness benefits in the animal kingdom.展开更多
Although green light(GL)is located in the middle of the visible light spectrum and regulates a series of plant developmental processes,the mechanism by which it regulates seedling development is largely unknown.In thi...Although green light(GL)is located in the middle of the visible light spectrum and regulates a series of plant developmental processes,the mechanism by which it regulates seedling development is largely unknown.In this study,we demonstrated that GL promotes atypical photomorphogenesis in Arabidopsis thaliana via the dual regulations of phytochrome B(phyB)and phyA.Although the Pr-to-Pfr conversion rates of phyB and phyA under GL were lower than those under red light(RL)in a fluence rate-dependent and time-dependent manner,long-term treatment with GL induced high Pfr/Pr ratios of phyB and phyA.Moreover,GL induced the formation of numerous small phyB photobodies in the nucleus,resulting in atypical photomorphogenesis,with smaller cotyledon opening angles and longer hypocotyls in seedlings compared to RL.The abundance of phyA significantly decreased after short-and long-term GL treatments.We determined that four major PHYTOCHROME-INTERACTING FACTORs(PIFs:PIF1,PIF3,PIF4,and PIF5)act downstream of phyB in GL-mediated cotyledon opening.In addition,GL plays opposite roles in regulating different PIFs.For example,under continuous GL,the protein levels of all PIFs decreased,whereas the transcript levels of PIF4 and PIF5 strongly increased compared with dark treatment.Taken together,our work provides a detailed molecular framework for understanding the role of the antagonistic regulations of phyB and phyA in GL-mediated atypical photomorphogenesis.展开更多
The lateral parabrachial nucleus(PBL)is implicated in the regulation of respiratory activity.Sodium leak channel(NALCN)mutations disrupt the respiratory rhythm and influence anesthetic sensitivity in both rodents and ...The lateral parabrachial nucleus(PBL)is implicated in the regulation of respiratory activity.Sodium leak channel(NALCN)mutations disrupt the respiratory rhythm and influence anesthetic sensitivity in both rodents and humans.Here,we investigated whether the NALCN in PBL glutamatergic neurons maintains respiratory function under general anesthesia.Our results showed that chemogenetic activation of PBL glutamatergic neurons increased the respiratory frequency(RF)in mice;whereas chemogenetic inhibition suppressed RF.NALCN knockdown in PBL glutamatergic neurons but not GABAergic neurons significantly reduced RF under physiological conditions and caused more respiratory suppression under sevoflurane anesthesia.NALCN knockdown in PBL glutamatergic neurons did not further exacerbate the respiratory suppression induced by propofol or morphine.Under sevoflurane anesthesia,painful stimuli rapidly increased the RF,which was not affected by NALCN knockdown in PBL glutamatergic neurons.This study suggested that the NALCN is a key ion channel in PBL glutamatergic neurons that maintains respiratory frequency under volatile anesthetic sevoflurane but not intravenous anesthetic propofol.展开更多
The inception and harnessing of excitons are paramount for the electroluminescence performance of organic light-emitting devices(OLEDs).Through-space charge transfer(TSCT)via intramolecular interaction has proved to b...The inception and harnessing of excitons are paramount for the electroluminescence performance of organic light-emitting devices(OLEDs).Through-space charge transfer(TSCT)via intramolecular interaction has proved to be one of the most potent techniques employed to achieve 100% internal quantum efficiency.However,molecular strategies utilized to comprehensively enhance the electroluminescent performance of TSCT emitters regarding improving the photoluminescence quantum yield(PLQY)and elevating the light out-coupling efficiency remain arduous.To surmount this challenge,we deliberately designed and synthesized a proof-of-concept TSCT emitter called CzO-TRZ by incorporating an extra carbazole donor into spiroheterocyclic architecture.The introduction of rigid spiral fragments can immensely boost the horizontal orientation dipole ratio and establish an extra through-bond charge transfer(TBCT)radiative decay channel.As a result,a very high PLQY of 98.7%,fast kRISCof 2.2×10^(5)s^(-1)and high k_(r)^(s) of 2.2×10^(7)s^(-1),and an ultrahigh horizontal dipolar ratio of 90%were concurrently achieved for Cz O-TRZ blended films.Furthermore,corresponding thermally activated delayed fluorescence(TADF)-and TADF-sensitized fluorescence(TSF)-OLEDs based on CzO-TRZ demonstrated external quantum efficiencies(EQEs)of 33.4% and 30.3%,respectively,highlighting its versatile applications as both an emitter and sensitized host.展开更多
Efficient ethanol oxidation reaction(EOR)is challenging due to the multiple reaction steps required to accomplish full oxidation to CO_(2) in fuel cells.Highentropy materials with the adjustable composition and unique...Efficient ethanol oxidation reaction(EOR)is challenging due to the multiple reaction steps required to accomplish full oxidation to CO_(2) in fuel cells.Highentropy materials with the adjustable composition and unique chemical structure provide a large configurational space for designing high-performance electrocatalysts.Herein,a new class of structurally ordered PtRhFeNiCu high-entropy intermetallics(HEIs)is developed as electrocatalyst,which exhibits excellent electrocatalytic activity and CO tolerance for EOR compared to high-entropy alloys(HEAs)comprising of same elements.When the HEIs are used as anode catalysts to be assembled into a high-temperature polybenzimidazole-based direct ethanol fuel cell,the HEIs achieve a high power density of 47.50 mW/cm^(2),which is 2.97 times of Pt/C(16.0mW/cm^(2)).Online gas chromatography measurements show that the developed HEIs have a stronger C–C bond-breaking ability than corresponding HEAs and Pt/C catalysts,which is further verified by density functional theory(DFT)calculations.Moreover,DFT results indicate that HEIs possess higher stability and electrochemical activity for EOR than HEAs.These results demonstrate that the HEIs could provide a new platform to develop highperformance electrocatalysts for broader applications.展开更多
Comprehensive Summary Inverted(p-i-n)perovskite solar cells(PSCs)are favored by researchers owing to their superior compatibility with flexible substrates and tandem device fabrication.Additionally,the hole transport ...Comprehensive Summary Inverted(p-i-n)perovskite solar cells(PSCs)are favored by researchers owing to their superior compatibility with flexible substrates and tandem device fabrication.Additionally,the hole transport layer(HTL)serves as a template for perovskite growth,which is critical for enhancing the device performance.However,the current research on how the HTL promotes perovskite crystallization is insufficient.Here,4PADCB,a self-assembled monolayer(SAM)hole transport material,was optimized as a superior template for perovskite growth through comparative analysis;accordingly,compact perovskite film with vertical growth was prepared.The better matched energy level alignment between 4PADCB and perovskite suppressed nonradiative recombination at the interface and enabled rapid hole extraction.Moreover,high-quality perovskite film growth on 4PADCB exhibited lower Young's modulus and less residual stress.By integrating 4PADCB into p-i-n PSCs,the optimal device achieved a power conversion efficiency of 24.80%,with an open-circuit voltage of 1.156 V,thus achieving the best rank among devices without perovskite post-treatment,additives,dopants,or intermediate layers.Furthermore,the unencapsulated device demonstrated exceptional thermostability and photostability under maximum power point tracking.Thus,this work provides a new understanding for the development of novel SAMs and perovskite growth,and it is expected to further improve device performance.展开更多
In electrochemical energy devices,the operating conditions always exert enormous influence on electrocatalysts'performances.Phosphoric acid(PA),acted as the proton carriers,can be adsorbed on Pt surface,block acti...In electrochemical energy devices,the operating conditions always exert enormous influence on electrocatalysts'performances.Phosphoric acid(PA),acted as the proton carriers,can be adsorbed on Pt surface,block active sites and affect the electronic structure of Pt unfavorably,which severely restricts the performance of high-temperature proton exchange membrane fuel cells(HT-PEMFCs).Herein,simply basic organic compounds,such as dicyandiamide(DCD),melamine(Mel)and cyanuric acid(CA),are decorated on Pt surface(DCD-Pt/C,Mel-Pt/C and CA-Pt/C)to induce the adsorption transfer of proton carriers.The decoration can not only inject electrons to Pt and enhance oxygen reduction reaction(ORR)activity but also can induce PA to transfer from Pt surface to organic compounds,decontaminating active sites.In addition,the organic compounds with the larger conjugated system and the smaller electronegativity of ligating atoms would have a greater interaction with Pt,causing a larger decoration amount on Pt surface,which leads to more excellent ORR activity and resistance to PA blockage effect.Therefore,MelPt/C shows a peak power density of 629 mW/cm^(2),exceeding commercial Pt/C(437 mW/cm^(2)),DCD-Pt/C(539 m W/cm^(2))and CA-Pt/C(511 mW/cm^(2))with the same loading.展开更多
Multi-model ensemble prediction is an effective approach for improving the prediction skill short-term climate prediction and evaluating related uncertainties. Based on a combination of localized operation outputs of ...Multi-model ensemble prediction is an effective approach for improving the prediction skill short-term climate prediction and evaluating related uncertainties. Based on a combination of localized operation outputs of Chinese climate models and imported forecast data of some international operational models, the National Climate Center of the China Meteorological Administration has established the China multi-model ensemble prediction system version 1.0 (CMMEv1.0) for monthly-seasonal prediction of primary climate variability modes and climate elements. We verified the real-time forecasts of CMMEv1.0 for the 2018 flood season (June-August) starting from March 2018 and evaluated the 1991-2016 hindcasts of CMMEv1.0. The results show that CMMEv1.0 has a significantly high prediction skill for global sea surface temperature (SST) anomalies, especially for the El Nino-Southern Oscillation (ENSO) in the tropical central-eastern Pacific. Additionally, its prediction skill for the North Atlantic SST triple (NAST) mode is high, but is relatively low for the Indian Ocean Dipole (IOD) mode. Moreover, CMMEv1.0 has high skills in predicting the western Pacific subtropical high (WPSH) and East Asian summer monsoon (EASM) in the June-July-August (JJA) season. The JJA air temperature in the CMMEv1.0 is predicted with a fairly high skill in most regions of China, while the JJA precipitation exhibits some skills only in northwestern and eastern China. For real-time forecasts in March-August 2018, CMMEv1.0 has accurately predicted the ENSO phase transition from cold to neutral in the tropical central-eastern Pacific and captures evolutions of the NAST and IOD indices in general. The system has also captured the main features of the summer WPSH and EASM indices in 2018, except that the predicted EASM is slightly weaker than the observed. Furthermore, CMMEv1.0 has also successfully predicted warmer air temperatures in northern China and captured the primary rainbelt over northern China, except that it predicted much more precipitation in the middle and lower reaches of the Yangtze River than observation.展开更多
Climate variability modes, usually known as primary climate phenomena, are well recognized as the most impor- tant predictability sources in subseasonal-interarmual climate prediction. This paper begins by reviewing t...Climate variability modes, usually known as primary climate phenomena, are well recognized as the most impor- tant predictability sources in subseasonal-interarmual climate prediction. This paper begins by reviewing the re- search and development carried out, and the recent progress made, at the Beijing Climate Center （BCC） in predicting some primary climate variability modes. These include the El Nifio-Southern Oscillation （ENSO）, Madden-Julian Oscillation （MJO）, and Arctic Oscillation （AO）, on global scales, as well as the sea surface temperature （SST） modes in the Indian Ocean and North Atlantic, western Pacific subtropical high （WPSH）, and the East Asian winter and summer monsoons （EAWM and EASM, respectively）, on regional scales. Based on its latest climate and statistical models, the BCC has established a climate phenomenon prediction system （CPPS） and completed a hindcast experi- ment for the period 1991-2014. The performance of the CPPS in predicting such climate variability modes is system- atically evaluated. The results show that skillful predictions have been made for ENSO, MJO, the Indian Ocean basin mode, the WPSH, and partly for the EASM, whereas less skillful predictions were made for the Indian Ocean Dipole （IOD） and North Atlantic SST Tripole, and no clear skill at all for the AO, subtropical IOD, and EAWM. Improve- ments in the prediction of these climate variability modes with low skill need to be achieved by improving the BCC＇s climate models, developing physically based statistical models as well as correction methods for model predictions. Some of the monitoring/prediction products of the BCC-CPPS are also introduced in this paper.展开更多
High-entropy alloys(HEAs)have been widely studied due to their unconventional compositions and unique physicochemical properties for various applications.Herein,for the first time,we propose a surface strain strategy ...High-entropy alloys(HEAs)have been widely studied due to their unconventional compositions and unique physicochemical properties for various applications.Herein,for the first time,we propose a surface strain strategy to tune the electrocatalytic activity of HEAs for methanol oxidation reaction(MOR).High-resolution aberration-corrected scanning transmission electron microscopy(STEM)and elemental mapping demonstrate both uniform atomic dispersion and the formation of a face-centered cubic(FCC)crystalline structure in Pt Fe Co Ni Cu HEAs.The HEAs obtained by heat treatment at 700℃(HEA-700)exhibit 0.94%compressive strain compared with that obtained at 400℃(HEA-400).As expected,the specific activity and mass activity of HEA-700 is higher than that of HEA-400 and most of the state-of-the-art catalysts.The enhanced MOR activity can be attributed to a shorter Pt–Pt bond distance in HEA-700 resulting from compressive strain.The nonprecious metal atoms in the core could generate compressive strain and down shift d-band centers via electron transfer to surface Pt layer.This work presents a new perspective for the design of high-performance HEAs electrocatalysts.展开更多
The structural,vibrational,and magnetic properties of well prepared Bi 1 x Y x FeO 3(x=0-0.1) powders are investigated by combining the X-ray diffraction,Raman scattering,differential scanning calorimetry,and magnetom...The structural,vibrational,and magnetic properties of well prepared Bi 1 x Y x FeO 3(x=0-0.1) powders are investigated by combining the X-ray diffraction,Raman scattering,differential scanning calorimetry,and magnetometry measurements.A structural symmetric breaking from the rhombohedral R3c to orthorhombic Pnma between x=0.07 and 0.1 is identified from the X-ray and Raman measurements,accompanying a ferroelectric-antiferroelectric phase transition.The remnant magnetization of Bi 0.9 Y 0.1 FeO 3 is about 15 times higher in magnitude compared to the pure BiFeO 3.Such a giant enhancement is suggested to result from the destruction of the spin cycloid accompanied with the structured transition.展开更多
文摘This study investigates the mechanical properties of Q235B steel through quasi-static tests at both room temperature and elevated temperature.The initial values of the Johnson-Cook model parameters are determined using a fitting method.The global response surface algorithm is employed to optimize and calibrate the Johnson-Cook model parameters for Q235B steel under both room temperature and elevated temperature conditions.A simulation model is established at room temperature,and the simulated mechanical performance curves for displacement and stress are monitored.Multiple optimization algorithms are applied to optimize and calibrate the model parameters at room temperature.The global response surface algorithm is identified as the most suitable algorithm for this optimization problem.Sensitivity analysis is conducted to explore the impact of model parameters on the objective function.The analysis indicates that the optimized material model better fits the experimental values,aligning more closely with the actual test results of material strain mechanisms over a wide temperature range.
基金supported by the National Natural Science Foundation of China (Grant Nos. 21905088, 21902047, 21573066, 21825201, 2187350, and 51402100)the Provincial Natural Science Foundation of Hunan (2020JJ5045)。
文摘Green and sustainable options are needed to ease the current energy and environmental crisis, and alleviate the greenhouse effect and energy shortage. As an alternative carbon–neutral synthetic fuel, ammonia shows great potential due to its high energy density, non-toxic by-products, and mature related infrastructures. However, related practical applications have been severely hampered on ammoniaoxidation due to the high cost of catalysts and immature energy utilization systems. Here, we comprehensively summarized the efforts which have been made in recent years with the aim of providing a deep sight into the development and deficiencies in this territory and trying to establish a simple framework of basic knowledge for researchers. The exploration of mechanism is discussed first and then the relevant catalysts studied in recent years are summarized. Besides, the progress of direct ammonia fuel cells(DAFCs) is also presented and the challenges as well as perspectives on future developments of electrocatalysts for ammonia electro-oxidation and its practical application are provided at the end.
基金supported by the Key-Area Research and Development Program of Guangdong Province(2020B090919005)the National Natural Science Foundation of China(U1801257,21975056,and 22179025)。
文摘Lithium-sulfur batteries(LSBs)have a high theoretical capacity,which is considered as one of the most promising high-energy-density secondary batteries due to the double electrons reaction of sulfur.However,the shuttle effects of lithium polysulfides(Li PSs)and sluggish redox kinetics lead to their materials capacity loss and cycle stability deterioration,which restrains LSBs commercialization.Metallic compounds as additions can improve the electrochemical performance of the Li-S system,through the trap of Li PSs and accelerate the conversion of the soluble Li PSs.Among of them,the iron group elements(Fe,Ni,Co)-based compounds are the promising materials for the LSBs,due to their unique outer electronic structure and its tunable properties,low cost,abundant in the earth,environmental benignity,controllable and scalable prepared,and so on.In this review,we have made a summary for iron-based compounds to capture Li PSs according to lithium bond,sulfur bond and magnetic force.The type of iron-based compound including oxides,sulfides,nitrides,phosphides,carbides,and so on,and we have investigated the electrocatalytic mechanism of these materials.Besides,some improvement strategies are proposed,such as the engineering of the special micro/nanostructure,defect concentrations,band structures,and heterostructures.We hope to shed an in-depth light on the rationally design and fabrication of robust,commercial and stable materials for high-performance LSBs.
基金support from the National Natural Science Foundation of China(51402100,21905088,21573066 and U19A2017)the Provincial Natural Science Foundation of Hunan(2020JJ5044,2022JJ10006)。
文摘Rationally manipulating surface reconstruction of catalysts for water oxidation,inducing formation and dynamic accumulation of catalytically active centers still face numerous challenges.Herein,the introduction of[Cr(C_(2)O_(4))_(3)]^(3-)into NiFe LDHs by intercalation engineering to promote surface reconstruction achieves an advanced oxygen evolution reaction(OER)activity.In view of the weak electronegativity of Cr^(3+) in[Cr(C_(2)O_(4))_(3)]^(3-),the intercalation of[Cr(C_(2)O_(4))_(3)]^(3-)is expected to result in an electron-rich structure of Fe sites in NiFe LDHs,and higher valence state of Ni can be formed with the charge transfer between Fe and Ni.The optimized electronic structure of NiFe-[Cr(C_(2)O_(4))_(3)]^(3-)-LDHs with more active Ni^(3+) species and the expedited dynamic generation of Ni^(3+) (Fe)OOH phase during the OER process contributed to its excellent catalytic property,revealed by in situ X-ray absorption spectroscopy,Raman spectroscopy,and quasi-in situ X-ray photoelectron spectroscopy.With the modulated electronic structure of metal sites,NiFe-[Cr(C_(2)O_(4))_(3)]^(3-)-LDHs exhibited promoted OER property with a lower overpotential of 236 mV at the current density of 10 mA cm^(-2).This work illustrates the intercalation of conjugated anion to dynamically construct desired Ni^(3+) sites with the optimal electronic environment for improved OER electrocatalysis.
文摘Better understanding of electrochemical reaction behaviors of hydrazine electrooxidation at metal phosphides has long been desired and the optimization of reaction kinetics has been proved to be operable.Herein,the dehydrogenation kinetics of hydrazine electrooxidation at Ni_(2)P is adjusted by Co as the(Ni_(0.6)Co_(0.4))_(2)P catalyzes HzOR effectively with onset potential of–45 mV and only 113 mV is needed to drive the current density of 50 mA cm^(‒2),showing over 60 mV lower than Ni_(2)P and Co_(2)P.It also delivers the maximum power density of 263.0 mW cm^(-2) for direct hydrazine fuel cell.Detailed experimental results revealed that Co doping not only decreases the adsorption energy of N_(2)H_(4) on Ni sites,lowering the energy barrier for dehydrogenation,but also acts as the active sites in the optimal reaction coordination to boost the reaction kinetics.This work represents a breakthrough in improving the catalytic performance of non‐precious metal electrocatalysts for hydrazine electrooxidation and highlights an energy‐saving electrochemical hydrogen production method.
基金jointly sponsored by the National Natural Science Foundation of China (Grant No. 41376018)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA11010303)+2 种基金the China Meteorological Administration Special Public Welfare Research Fund (GYHY201506013)the Project for Development of Key Techniques in Meteorological Forecasting Operation (YBGJXM201705)the Open Foundation of the LASG/IAP/CAS
文摘The ＂summer prediction barrier＂ （SPB） of SST anomalies （SSTA） over the Kuroshio--Oyashio Extension （KOE） refers to the phenomenon that prediction errors of KOE-SSTA tend to increase rapidly during boreal summer, resulting in large prediction uncertainties. The fast error growth associated with the SPB occurs in the mature-to-decaying transition phase, which is usually during the August-September-October （ASO） season, of the KOE-SSTA events to be predicted. Thus, the role of KOE-SSTA evolutionary characteristics in the transition phase in inducing the SPB is explored by performing perfect model predictability experiments in a coupled model, indicating that the SSTA events with larger mature-to-decaying transi- tion rates （Category-l） favor a greater possibility of yielding a more significant SPB than those events with smaller transition rates （Category-2）. The KOE-SSTA events in Category-1 tend to have more significant anomalous Ekman pumping in their transition phase, resulting in larger prediction errors of vertical oceanic temperature advection associated with the SSTA events. Consequently, Category-1 events possess faster error growth and larger prediction errors. In addition, the anomalous Ekman upwelling （downwelling） in the ASO season also causes SSTA cooling （warming）, accelerating the transition rates of warm （cold） KOE-SSTA events. Therefore, the SSTA transition rate and error growth rate are both related with the anomalous Ekman pumping of the SSTA events to be predicted in their transition phase. This may explain why the SSTA events transferring more rapidly from the mature to decaying phase tend to have a greater possibility of yielding a more significant SPB.
基金supported by the National Natural Science Foundation of China(31501175)Grants of Anhui Natural Science Foundation(20230302123239)Talent Grants of Anhui Agricultural University(RC342201).
文摘Collective behaviors efficiently impart benefits to a diversity of species ranging from bacteria to humans.Fly larvae tend to cluster and form coordinated digging groups under crowded conditions,yet understanding the rules governing this behavior is in its infancy.We primarily took advantage of the Drosophila model to investigate cooperative foraging behavior.Here,we report that Drosophila-related species and the black soldier fly have evolved a conserved strategy of cluster digging in food foraging.Subsequently,we investigated relative factors,including larval stage,population density,and food stiffness and quality,that affect the cluster digging behavior.Remarkably,oxygen supply through the posterior breathing spiracles is necessary for the organization of digging clusters.More importantly,we theoretically devise a mathematical model to accurately calculate how the cluster digging behavior expands food resources by diving depth,cross-section area,and food volume.We found that cluster digging behavior approximately increases 2.2 fold depth,1.7-fold cross-section area,and 1.9 fold volume than control groups,respectively.Amplification of food sources significantly facilitates survival,larval development,and reproductive success of Drosophila challenged with competition for limited food resources,thereby conferring trophic benefits to fitness in insects.Overall,our findings highlight that the cluster digging behavior is a pivotal behavior for their adaptation to food scarcity,advancing a better understanding of how this cooperative behavior confers fitness benefits in the animal kingdom.
基金supported by the Excellent Young Talents Fund Program of Higher Education Institutions of Anhui Province(2023AH030049)Anhui Agricultural University Startup Fund(grant no.rc422115,to J.J.L.)Anhui Province Fund for University Development(22103103)。
文摘Although green light(GL)is located in the middle of the visible light spectrum and regulates a series of plant developmental processes,the mechanism by which it regulates seedling development is largely unknown.In this study,we demonstrated that GL promotes atypical photomorphogenesis in Arabidopsis thaliana via the dual regulations of phytochrome B(phyB)and phyA.Although the Pr-to-Pfr conversion rates of phyB and phyA under GL were lower than those under red light(RL)in a fluence rate-dependent and time-dependent manner,long-term treatment with GL induced high Pfr/Pr ratios of phyB and phyA.Moreover,GL induced the formation of numerous small phyB photobodies in the nucleus,resulting in atypical photomorphogenesis,with smaller cotyledon opening angles and longer hypocotyls in seedlings compared to RL.The abundance of phyA significantly decreased after short-and long-term GL treatments.We determined that four major PHYTOCHROME-INTERACTING FACTORs(PIFs:PIF1,PIF3,PIF4,and PIF5)act downstream of phyB in GL-mediated cotyledon opening.In addition,GL plays opposite roles in regulating different PIFs.For example,under continuous GL,the protein levels of all PIFs decreased,whereas the transcript levels of PIF4 and PIF5 strongly increased compared with dark treatment.Taken together,our work provides a detailed molecular framework for understanding the role of the antagonistic regulations of phyB and phyA in GL-mediated atypical photomorphogenesis.
基金supported by the National Natural Science Foundation of China(82271290 and 82301403)the Natural Science Foundation of Sichuan Province(2022NSFSC1399)+1 种基金the Health Commission of Sichuan Province(21PJ014)the Key R&D(Major Science and Technology Project)of the Sichuan Science and Technology Department(2023YFS0138 and 2023ZYD0168).
文摘The lateral parabrachial nucleus(PBL)is implicated in the regulation of respiratory activity.Sodium leak channel(NALCN)mutations disrupt the respiratory rhythm and influence anesthetic sensitivity in both rodents and humans.Here,we investigated whether the NALCN in PBL glutamatergic neurons maintains respiratory function under general anesthesia.Our results showed that chemogenetic activation of PBL glutamatergic neurons increased the respiratory frequency(RF)in mice;whereas chemogenetic inhibition suppressed RF.NALCN knockdown in PBL glutamatergic neurons but not GABAergic neurons significantly reduced RF under physiological conditions and caused more respiratory suppression under sevoflurane anesthesia.NALCN knockdown in PBL glutamatergic neurons did not further exacerbate the respiratory suppression induced by propofol or morphine.Under sevoflurane anesthesia,painful stimuli rapidly increased the RF,which was not affected by NALCN knockdown in PBL glutamatergic neurons.This study suggested that the NALCN is a key ion channel in PBL glutamatergic neurons that maintains respiratory frequency under volatile anesthetic sevoflurane but not intravenous anesthetic propofol.
基金supported by the National Natural Science Foundation of China(U21A20331,51773212,81903743,52003088)the Distinguished Young Scholars(21925506)the Ningbo Key Scientific and Technological Project(2022Z124,2022Z119)。
文摘The inception and harnessing of excitons are paramount for the electroluminescence performance of organic light-emitting devices(OLEDs).Through-space charge transfer(TSCT)via intramolecular interaction has proved to be one of the most potent techniques employed to achieve 100% internal quantum efficiency.However,molecular strategies utilized to comprehensively enhance the electroluminescent performance of TSCT emitters regarding improving the photoluminescence quantum yield(PLQY)and elevating the light out-coupling efficiency remain arduous.To surmount this challenge,we deliberately designed and synthesized a proof-of-concept TSCT emitter called CzO-TRZ by incorporating an extra carbazole donor into spiroheterocyclic architecture.The introduction of rigid spiral fragments can immensely boost the horizontal orientation dipole ratio and establish an extra through-bond charge transfer(TBCT)radiative decay channel.As a result,a very high PLQY of 98.7%,fast kRISCof 2.2×10^(5)s^(-1)and high k_(r)^(s) of 2.2×10^(7)s^(-1),and an ultrahigh horizontal dipolar ratio of 90%were concurrently achieved for Cz O-TRZ blended films.Furthermore,corresponding thermally activated delayed fluorescence(TADF)-and TADF-sensitized fluorescence(TSF)-OLEDs based on CzO-TRZ demonstrated external quantum efficiencies(EQEs)of 33.4% and 30.3%,respectively,highlighting its versatile applications as both an emitter and sensitized host.
基金National Key R&D Program of China,Grant/Award Number:2020YFA0710000the National Natural Science Foundation of China,Grant/Award Numbers:21825201,U19A2017 and,22102053+4 种基金the Provincial Natural Science Foundation of Hunan,Grant/Award Numbers:2016TP1009 and,2020JJ5045the Postgraduate Scientific Research Innovation Project of Hunan Province,Grant/Award Number:CX20200441the Australian Research Council,Grant/Award Number:CE 140100012the Australian National Fabrication Facility-UOW Electron Microscopy Centre,Compute Canada,Natural Sciences and Engineering Research Council of Canada(NSERC)the University of Toronto.
文摘Efficient ethanol oxidation reaction(EOR)is challenging due to the multiple reaction steps required to accomplish full oxidation to CO_(2) in fuel cells.Highentropy materials with the adjustable composition and unique chemical structure provide a large configurational space for designing high-performance electrocatalysts.Herein,a new class of structurally ordered PtRhFeNiCu high-entropy intermetallics(HEIs)is developed as electrocatalyst,which exhibits excellent electrocatalytic activity and CO tolerance for EOR compared to high-entropy alloys(HEAs)comprising of same elements.When the HEIs are used as anode catalysts to be assembled into a high-temperature polybenzimidazole-based direct ethanol fuel cell,the HEIs achieve a high power density of 47.50 mW/cm^(2),which is 2.97 times of Pt/C(16.0mW/cm^(2)).Online gas chromatography measurements show that the developed HEIs have a stronger C–C bond-breaking ability than corresponding HEAs and Pt/C catalysts,which is further verified by density functional theory(DFT)calculations.Moreover,DFT results indicate that HEIs possess higher stability and electrochemical activity for EOR than HEAs.These results demonstrate that the HEIs could provide a new platform to develop highperformance electrocatalysts for broader applications.
基金supported by the National Science Fund for Distinguished Young Scholars(21925506)National Natural Science Foundation of China(U21A20331,81903743,22209192 and 62275251)+1 种基金Natural Science Foundation of Zhejiang Province(LY24F040002)China Postdoctoral Science Foundation(2022M713242).
文摘Comprehensive Summary Inverted(p-i-n)perovskite solar cells(PSCs)are favored by researchers owing to their superior compatibility with flexible substrates and tandem device fabrication.Additionally,the hole transport layer(HTL)serves as a template for perovskite growth,which is critical for enhancing the device performance.However,the current research on how the HTL promotes perovskite crystallization is insufficient.Here,4PADCB,a self-assembled monolayer(SAM)hole transport material,was optimized as a superior template for perovskite growth through comparative analysis;accordingly,compact perovskite film with vertical growth was prepared.The better matched energy level alignment between 4PADCB and perovskite suppressed nonradiative recombination at the interface and enabled rapid hole extraction.Moreover,high-quality perovskite film growth on 4PADCB exhibited lower Young's modulus and less residual stress.By integrating 4PADCB into p-i-n PSCs,the optimal device achieved a power conversion efficiency of 24.80%,with an open-circuit voltage of 1.156 V,thus achieving the best rank among devices without perovskite post-treatment,additives,dopants,or intermediate layers.Furthermore,the unencapsulated device demonstrated exceptional thermostability and photostability under maximum power point tracking.Thus,this work provides a new understanding for the development of novel SAMs and perovskite growth,and it is expected to further improve device performance.
基金supported by the National Key R&D Program of China(No.2021YFA1500900)the National Natural Science Foundation of China(Nos.22102053,21825201,22172047 and U19A2017)+7 种基金the Provincial Natural Science Foundation of Hunan(Nos.2019GK2031,2016TP1009,2020JJ5045 and 2021JJ30089)the Science and Technology Innovation Program of Hunan Province,China(Nos.2020RC2020,2022RC1036)Shenzhen Science and Technology Program(No.JCYJ20210324122209025)Basic and Applied Basic Research Foundation of Guangdong Province-Regional joint fund project(No.2021B1515120024)Natural Science Foundation of Chongqing(No.cstc2021jcyj-msxmX0770)the Science Funds of the Education Office of Jiangxi Province(No.GJJ2201324)the Science Funds of Jiangxi Province(No.20224BAB213018)the China Postdoctoral Science Foundation(Certificate No.2023M741121)。
文摘In electrochemical energy devices,the operating conditions always exert enormous influence on electrocatalysts'performances.Phosphoric acid(PA),acted as the proton carriers,can be adsorbed on Pt surface,block active sites and affect the electronic structure of Pt unfavorably,which severely restricts the performance of high-temperature proton exchange membrane fuel cells(HT-PEMFCs).Herein,simply basic organic compounds,such as dicyandiamide(DCD),melamine(Mel)and cyanuric acid(CA),are decorated on Pt surface(DCD-Pt/C,Mel-Pt/C and CA-Pt/C)to induce the adsorption transfer of proton carriers.The decoration can not only inject electrons to Pt and enhance oxygen reduction reaction(ORR)activity but also can induce PA to transfer from Pt surface to organic compounds,decontaminating active sites.In addition,the organic compounds with the larger conjugated system and the smaller electronegativity of ligating atoms would have a greater interaction with Pt,causing a larger decoration amount on Pt surface,which leads to more excellent ORR activity and resistance to PA blockage effect.Therefore,MelPt/C shows a peak power density of 629 mW/cm^(2),exceeding commercial Pt/C(437 mW/cm^(2)),DCD-Pt/C(539 m W/cm^(2))and CA-Pt/C(511 mW/cm^(2))with the same loading.
基金Supported by the National Key Research and Development Program of China(2017YFC1502306,2017YFC1502302,and 2018YFC-1506004)China Meteorological Administration Special Project for Developing Key Techniques for Operational Meteorological Forecast(YBGJXM201805)
文摘Multi-model ensemble prediction is an effective approach for improving the prediction skill short-term climate prediction and evaluating related uncertainties. Based on a combination of localized operation outputs of Chinese climate models and imported forecast data of some international operational models, the National Climate Center of the China Meteorological Administration has established the China multi-model ensemble prediction system version 1.0 (CMMEv1.0) for monthly-seasonal prediction of primary climate variability modes and climate elements. We verified the real-time forecasts of CMMEv1.0 for the 2018 flood season (June-August) starting from March 2018 and evaluated the 1991-2016 hindcasts of CMMEv1.0. The results show that CMMEv1.0 has a significantly high prediction skill for global sea surface temperature (SST) anomalies, especially for the El Nino-Southern Oscillation (ENSO) in the tropical central-eastern Pacific. Additionally, its prediction skill for the North Atlantic SST triple (NAST) mode is high, but is relatively low for the Indian Ocean Dipole (IOD) mode. Moreover, CMMEv1.0 has high skills in predicting the western Pacific subtropical high (WPSH) and East Asian summer monsoon (EASM) in the June-July-August (JJA) season. The JJA air temperature in the CMMEv1.0 is predicted with a fairly high skill in most regions of China, while the JJA precipitation exhibits some skills only in northwestern and eastern China. For real-time forecasts in March-August 2018, CMMEv1.0 has accurately predicted the ENSO phase transition from cold to neutral in the tropical central-eastern Pacific and captures evolutions of the NAST and IOD indices in general. The system has also captured the main features of the summer WPSH and EASM indices in 2018, except that the predicted EASM is slightly weaker than the observed. Furthermore, CMMEv1.0 has also successfully predicted warmer air temperatures in northern China and captured the primary rainbelt over northern China, except that it predicted much more precipitation in the middle and lower reaches of the Yangtze River than observation.
基金Supported by the National(Key)Basic Research and Development(973)Program of China(2015CB453203)China Meteorological Administration Special Public Welfare Research Fund(GYHY201506013 and GYHY201406022)+3 种基金National Natural Science Foundation of China(41205058,41375062,41405080,41505065,41606019,and 41605116)US National Science Foundation(AGS-1406601)US Department of Energy(DOE)(DE-SC000511)the UK–China Research&Innovation Partnership Fund through the Met Office Climate Science for Service Partnership(CSSP) China as part of the Newton Fund
文摘Climate variability modes, usually known as primary climate phenomena, are well recognized as the most impor- tant predictability sources in subseasonal-interarmual climate prediction. This paper begins by reviewing the re- search and development carried out, and the recent progress made, at the Beijing Climate Center （BCC） in predicting some primary climate variability modes. These include the El Nifio-Southern Oscillation （ENSO）, Madden-Julian Oscillation （MJO）, and Arctic Oscillation （AO）, on global scales, as well as the sea surface temperature （SST） modes in the Indian Ocean and North Atlantic, western Pacific subtropical high （WPSH）, and the East Asian winter and summer monsoons （EAWM and EASM, respectively）, on regional scales. Based on its latest climate and statistical models, the BCC has established a climate phenomenon prediction system （CPPS） and completed a hindcast experi- ment for the period 1991-2014. The performance of the CPPS in predicting such climate variability modes is system- atically evaluated. The results show that skillful predictions have been made for ENSO, MJO, the Indian Ocean basin mode, the WPSH, and partly for the EASM, whereas less skillful predictions were made for the Indian Ocean Dipole （IOD） and North Atlantic SST Tripole, and no clear skill at all for the AO, subtropical IOD, and EAWM. Improve- ments in the prediction of these climate variability modes with low skill need to be achieved by improving the BCC＇s climate models, developing physically based statistical models as well as correction methods for model predictions. Some of the monitoring/prediction products of the BCC-CPPS are also introduced in this paper.
基金supported by the National Natural Science Foundation of China (51402100, 21573066, 21825201, 22002039, and 21522305)the Scientific Research Foundation of Hunan Provincial Education Department (19C0054)+2 种基金the Postgraduate Scientific Research Innovation Project of Hunan Province (CX20200441)the Australian Research Council (CE 140100012)the Australian National Fabrication Facility | UOW Electron Microscopy Centre, and Compute Canada, Natural Sciences and Engineering Research Council of Canada (NSERC), University of Toronto
文摘High-entropy alloys(HEAs)have been widely studied due to their unconventional compositions and unique physicochemical properties for various applications.Herein,for the first time,we propose a surface strain strategy to tune the electrocatalytic activity of HEAs for methanol oxidation reaction(MOR).High-resolution aberration-corrected scanning transmission electron microscopy(STEM)and elemental mapping demonstrate both uniform atomic dispersion and the formation of a face-centered cubic(FCC)crystalline structure in Pt Fe Co Ni Cu HEAs.The HEAs obtained by heat treatment at 700℃(HEA-700)exhibit 0.94%compressive strain compared with that obtained at 400℃(HEA-400).As expected,the specific activity and mass activity of HEA-700 is higher than that of HEA-400 and most of the state-of-the-art catalysts.The enhanced MOR activity can be attributed to a shorter Pt–Pt bond distance in HEA-700 resulting from compressive strain.The nonprecious metal atoms in the core could generate compressive strain and down shift d-band centers via electron transfer to surface Pt layer.This work presents a new perspective for the design of high-performance HEAs electrocatalysts.
基金supported by the Cultivation Fund of the Key Scientific and Technical Innovation Project,Ministry of Education of China (Grant No.708070)the National Natural Science Foundation of China (GrantNos. 10874046 and 11104081)
文摘The structural,vibrational,and magnetic properties of well prepared Bi 1 x Y x FeO 3(x=0-0.1) powders are investigated by combining the X-ray diffraction,Raman scattering,differential scanning calorimetry,and magnetometry measurements.A structural symmetric breaking from the rhombohedral R3c to orthorhombic Pnma between x=0.07 and 0.1 is identified from the X-ray and Raman measurements,accompanying a ferroelectric-antiferroelectric phase transition.The remnant magnetization of Bi 0.9 Y 0.1 FeO 3 is about 15 times higher in magnitude compared to the pure BiFeO 3.Such a giant enhancement is suggested to result from the destruction of the spin cycloid accompanied with the structured transition.
