It is well-known that the equilibrium isotope fractionation of mercury(Hg)includes classical massdependent fractionations(MDFs)and nuclear volume effect(NVE)induced mass-independent fractionations(MIFs).However,the ef...It is well-known that the equilibrium isotope fractionation of mercury(Hg)includes classical massdependent fractionations(MDFs)and nuclear volume effect(NVE)induced mass-independent fractionations(MIFs).However,the effect of the NVE on these kinetic processes is not known.The total fractionations(MDFs+NVEinduced MIFs)of several representative Hg-incorporated substances were selected and calculated with ab initio calculations in this work for both equilibrium and kinetic processes.NVE-induced MIFs were calculated with scaled contact electron densities at the nucleus through systematic evaluations of their accuracy and errors using the Gaussian09 and DIRAC19 packages(named the electron density scaling method).Additionally,the NVE-induced kinetic isotope effect(KIE)of Hg isotopes are also calculated with this method for several representative Hg oxidation reactions by chlorine species.Total KIEs for 202 Hg/^(198)Hg ranging from−2.27‰to 0.96‰are obtained.Three anomalous^(202)Hg-enriched KIEs(δ^(202)Hg/^(198)Hg=0.83‰,0.94‰,and 0.96‰,)caused by the NVE are observed,which are quite different from the classical view(i.e.,light isotopes react faster than the heavy ones).The electron density scaling method we developed in this study can provide an easier way to calculate the NVE-induced KIEs for heavy isotopes and serve to better understand the fractionation mechanisms of mercury isotope systems.展开更多
Using resting-state functional magnetic resonance imaging (fMRI) technology to assist in identifying brain diseases has great potential. In the identification of brain diseases, graph-based models have been widely use...Using resting-state functional magnetic resonance imaging (fMRI) technology to assist in identifying brain diseases has great potential. In the identification of brain diseases, graph-based models have been widely used, where graph represents the similarity between patients or brain regions of interest. In these models, constructing high-quality graphs is of paramount importance. Researchers have proposed various methods for constructing graphs from different perspectives, among which the simplest and most popular one is Pearson Correlation (PC). Although existing methods have achieved significant results, these graphs are usually fixed once they are constructed, and are generally operated separately from downstream task. Such a separation may result in neither the constructed graph nor the extracted features being ideal. To solve this problem, we use the graph-optimized locality preserving projection algorithm to extract features and the population graph simultaneously, aiming in higher identification accuracy through a task-dependent automatic optimization of the graph. At the same time, we incorporate supervised information to enable more flexible modelling. Specifically, the proposed method first uses PC to construct graph as the initial feature for each subject. Then, the projection matrix and graph are iteratively optimized through graph-optimization locality preserving projections based on semi-supervised learning, which fully employs the knowledge in various transformation spaces. Finally, the obtained projection matrix is applied to construct the subject-level graph and perform classification using support vector machines. To verify the effectiveness of the proposed method, we conduct experiments to identify subjects with mild cognitive impairment (MCI) and Autism spectrum disorder (ASD) from normal controls (NCs), and the results showed that the classification performance of our method is better than that of the baseline method.展开更多
Photothermal catalysis realizes the synergistic effect of solar energy and thermochemistry,which also has the potential to improve the reaction rate and optimize the selectivity.In this review,the research progress of...Photothermal catalysis realizes the synergistic effect of solar energy and thermochemistry,which also has the potential to improve the reaction rate and optimize the selectivity.In this review,the research progress of photothermal catalytic removal of volatile organic compounds(VOCs)by nano-catalysts in recent years is systematically reviewed.First,the fundamentals of photothermal catalysis and the fabrication of catalysts are described,and the design strategy of optimizing photothermal catalysis performance is proposed.Second,the performance for VOC degradation with photothermal catalysis is evaluated and compared for the batch and continuous systems.Particularly,the catalytic mechanism of VOC oxidation is systematically introduced based on experimental and theoretical study.Finally,the future limitations and challenges have been discussed,and potential research directions and priorities are highlighted.A broad view of recent photothermal catalyst fabrication,applications,challenges,and prospects can be systemically provided by this review.展开更多
Germination,a powerful biofortification technique,holds immense potential in bolstering the micronutrient profile of essential staple grains,thereby paving the way for optimal nutritional enhancement.The primary goal ...Germination,a powerful biofortification technique,holds immense potential in bolstering the micronutrient profile of essential staple grains,thereby paving the way for optimal nutritional enhancement.The primary goal of this study was to improve the technological functionality of germinated wheat flour by incorporating pentosanase(Pn)and glucose oxidase(Gox)enzymes,with particular emphasis on the evolutionary changes in its components.The inclusion of Gox did not produce any substantial impact on the volumetric characteristics of the steamed bread.The incorporation of Pn and Gox has been seen to enhance the overall excellence of steamed bread by optimizing loaf volume and textural characteristics while also improving the thermal stability of the dough.The existence of two endothermic peaks could be attributed to bound water or alterations in the granules within the starch crystallization region.Adding Pn and Gox reduced and increased the formation and stability time of the dough,respectively.A certain ratio was employed to assess alternations in the crystallinity of starch granules over a limited range.After steaming,a significant decrease in IR1047/1022 was observed,indicating that the elevated temperature partially disrupted the internal starch crystal structure,leading to a gelatinization reaction with water.The ratio of tensile resistance(R)and elongation(E)of dough increased significantly compared to the control.The results obtained from this study indicate that the simultaneous inclusion of enzymes(Pn+Gox)holds significant promise for expanding the technological functionality of germinated wheat flour dough and improving the quality attributes of steamed bread.展开更多
[Objectives]This study aimed to optimize the ultrasonic-assisted extraction process of total flavonoids from a Zhuang medicine HERBA BLUMEAE RIPARIAE using response surface methodology.[Methods]Using rutin as a refere...[Objectives]This study aimed to optimize the ultrasonic-assisted extraction process of total flavonoids from a Zhuang medicine HERBA BLUMEAE RIPARIAE using response surface methodology.[Methods]Using rutin as a reference substance,a standard curve was drawn at a wavelength of 292 nm.Content determination was performed through absorbance under different conditions.The effects of ultrasonic time,ethanol volume fraction and liquid-to-solid ratio on the yield of total flavonoids from HERBA BLUMEAE RIPARIAE were investigated by single-factor tests.By using Box-Behnken test,the ultrasonic-assisted extraction process of total flavonoids from HERBA BLUMEAE RIPARIAE was optimized.[Results]The optimal extraction process of total flavonoids from HERBA BLUMEAE RIPARIAE was as follows:ultrasonic time of 30 min,ethanol volume fraction of 50%and liquid-to-solid ratio of 40∶1(mL/g).Under the optimal extraction conditions,the average yield of total flavonoids from HERBA BLUMEAE RIPARIAE was 85.47 mg/g.[Conclusions]The optimized extraction process was convenient and feasible.This study will provide a reference for the extraction of total flavonoids from HERBA BLUMEAE RIPARIAE,and provide certain guidance and basis for further development and utilization of the plan resource of Blumea riparia(Bl.)DC.展开更多
Understanding the origin of ocean island basalts(OIB) has important bearings on Earth's deep mantle.Although it is widely accepted that subducted oceanic crust, as a consequence of plate tectonics, contributes mat...Understanding the origin of ocean island basalts(OIB) has important bearings on Earth's deep mantle.Although it is widely accepted that subducted oceanic crust, as a consequence of plate tectonics, contributes material to OIB's formation, its exact fraction in OIB's mantle source remains ambiguous largely due to uncertainties associated with existing geochemical proxies. Here we show, through theoretical calculation, that unlike many known proxies, triple oxygen isotope compositions(i.e.D^(17 )O) in olivine samples are not affected by crystallization and partial melting. This unique feature, therefore, allows olivine D^(17 )O values to identify subducted oceanic crusts in OIB's mantle source. Furthermore, the fractions of subducted ocean sediments and hydrothermally altered oceanic crust in OIB's mantle source can be quantified using their characteristic D^(17 )O values. Based on published D^(17 )O data, we estimated the fraction of subducted oceanic crust to be as high as 22.3% in certain OIB, but the affected region in the respective mantle plume is likely to be limited.展开更多
With significant advances in mass spectrometry for isotope analysis in the last decade,e.g.,negative thermal ionization mass spectrometry and multi-collector inductively coupled plasma mass spectrometry,high-precision...With significant advances in mass spectrometry for isotope analysis in the last decade,e.g.,negative thermal ionization mass spectrometry and multi-collector inductively coupled plasma mass spectrometry,high-precision(ppm-level)measurements of tungsten(W)isotopes have been widely used for early earth differentiation processes,such as metal-silicate segregation,melting and crystallization processes during the magma ocean,and putative core-mantle exchange and dynamics.Here,we give a brief review of works on ^(182)W anomalies in terrestrial samples,including methods,results,explanations,implications,and prospects.The review will be presented by including the following parts:the introduction of W isotopes and the short-lived radioactive ^(182)Hf-^(182)W system;data notations and W isotope measurement methods;^(182)W anomalies observed in terrestrial samples;a summary of models developed for interpreting origins of positive and negative ^(182)W anomalies;future prospects.展开更多
We attempt to model magnetic reconnection during the two-ribbon flare in a gravitationally stratified solar atmosphere with the Lundquist number of S=10~6 using 2 D simulations.We found that the tearing mode instabili...We attempt to model magnetic reconnection during the two-ribbon flare in a gravitationally stratified solar atmosphere with the Lundquist number of S=10~6 using 2 D simulations.We found that the tearing mode instability leads to inhomogeneous turbulence inside the reconnecting current sheet(CS)and invokes the fast phase of reconnection.Fast reconnection brings an extra dissipation of magnetic field which enhances the reconnection rate in an apparent way.The energy spectrum in the CS shows a power law pattern and the dynamics of plasmoids govern the associated spectral index.We noticed that the energy dissipation occurs at a scale l_(ko)of 100-200 km,and the associated CS thickness ranges from 1500 to 2500 km,which follows the Taylor scale l_(T)=l_(ko)S_(1/6).The termination shock(TS)appears in the turbulent region above flare loops,which is an important contributor to heating flare loops.Substantial magnetic energy is converted into both kinetic and thermal energies via TS,and the cumulative heating rate is greater than the rate of the kinetic energy transfer.In addition,the turbulence is somehow amplified by TS,in which the amplitude is related to the local geometry of the TS.展开更多
This study established a method for isolating large numbers of high-purity osteocytes from high-density bone.Bone fragments derived from mice tibia and femurs were alternately digested with type I collagenase and EDTA...This study established a method for isolating large numbers of high-purity osteocytes from high-density bone.Bone fragments derived from mice tibia and femurs were alternately digested with type I collagenase and EDTA nine times,and the digested cells and bone chips(BC)were cultured,digested,and passaged when cells were fully grown.The types of cells obtained were identified by morphology,viable cell counts,alkaline phosphatase staining,and biochemical activity analyses,and specific osteocyte and osteoblast markers were evaluated by quantitative real-time polymerase chain reaction.Our results showed that among the cells obtained from the third digestion(fractions 7–9)of wild mice tibias and femurs and the remaining BCs,85%–90%of the cells were osteocytes.Moreover,their morphology was approximately one-tenth to one-fifth the size of osteoblasts,star-shaped or polygonal,with a dendritic structure,negative for alkaline phosphatase staining,and showed a high expression of dmp1 and sclerostin.Ninety percent of the cells in fractions 1–3 were osteoblasts,and were fusiform or polygonal shape.The activity of osteoblast-specific alkaline phosphatase and mRNA expression were high in this fraction,while the expression of osteocyte-specific dmp1 and sclerostin was not detected.In the second portion(fractions 4–6),a large number were osteoblasts,mixed with a small number of osteocytes,and had high alkaline phosphatase activity and osteocyte mRNA levels,a specific level of the osteocyte marker dmp1,and no sclerostin was detected.Osteocytes in daβcatot mice were also successfully isolated by this method,and we found that Wnt signaling increased the proliferation of these osteocytes.The proposed method can be used to culture osteocytes and osteoblasts of high purity and can be used for isolation and culture of these two kinds of cells from high-density bone,which provides an avenue for the study of osteocyte function in vitro.展开更多
Purpose: Brain functional networks (BFNs) has become important approach for diagnosis of some neurological or psychological disorders. Before estimating BFN, obtaining blood oxygen level dependent (BOLD) representativ...Purpose: Brain functional networks (BFNs) has become important approach for diagnosis of some neurological or psychological disorders. Before estimating BFN, obtaining blood oxygen level dependent (BOLD) representative signals from brain regions of interest (ROIs) is important. In the past decades, the common method is generally to take a ROI as a node, averaging all the voxel time series inside it to extract a representative signal. However, one node does not represent the entire information of this ROI, and averaging method often leads to signal cancellation and information loss. Inspired by this, we propose a novel model extraction method based on an assumption that a ROI can be represented by multiple nodes. Methods: In this paper, we first extract multiple nodes (the number is user-defined) from the ROI based on two traditional methods, including principal component analysis (PCA), and K-means (Clustering according to the spatial position of voxels). Then, canonical correlation analysis (CCA) was issued to construct BFNs by maximizing the correlation between the representative signals corresponding to the nodes in any two ROIs. Finally, to further verify the effectiveness of the proposed method, the estimated BFNs are applied to identify subjects with autism spectrum disorder (ASD) and mild cognitive impairment (MCI) from health controls (HCs). Results: Experimental results on two benchmark databases demonstrate that the proposed method outperforms the baseline method in the sense of classification performance. Conclusions: We propose a novel method for obtaining nodes of ROId based on the hypothesis that a ROI can be represented by multiple nodes, that is, to extract the node signals of ROIs with K-means or PCA. Then, CCA is used to construct BFNs.展开更多
Designing catalyst to achieve ammonia synthesis at mild conditions is a meaningful challenge in catalysis community.Defective g-C_(3)N_(4)nanosheet supported single-cluster ruthenium and iron catalysts were investigat...Designing catalyst to achieve ammonia synthesis at mild conditions is a meaningful challenge in catalysis community.Defective g-C_(3)N_(4)nanosheet supported single-cluster ruthenium and iron catalysts were investigated for their ammonia synthesis performance.Based on density functional theory(DFT)calculations and microkinetic simulations,Ru_(3)single-cluster anchored on defective g-C3N4 nanosheet(Ru_(3)/Nv-g-C_(3)N_(4))has a turnover frequency(TOF)5.8 times higher than the Ru(0001)step surface at industrial reaction conditions of 673 K and 100 bar for ammonia synthesis.In other words,similar TOFs could be achieved on Ru_(3)/Nv-g-C_(3)N_(4)at much milder conditions(623 K,30 bar)than on Ru(0001)(673 K,100 bar).Our computations reveal the reaction proceeds parallelly on Ru_(3)/Nv-g-C_(3)N_(4)through both dissociative and alternative associative mechanisms at typical reaction conditions(600–700 K,10–100 bar);N–N bond cleavage of*N2 and*NNH from the two respective pathways controls the reaction collectively.With increasing temperatures or decreasing pressures,the dissociative mechanism gradually prevails and associative mechanism recedes.In comparison,Fe_(3)/Nv-g-C_(3)N_(4)catalyst shows a much lower catalytic activity than Ru3/Nv-g-C_(3)N_(4)by two orders of magnitude and the reaction occurs solely through the dissociative pathway.The finding provides a prospective candidate and deepens the mechanistic understanding for ammonia synthesis catalyzed by single-cluster catalysts(SCCs).展开更多
Garnet-type oxide solid electrolytes are the critical materials for all-solid-state lithium ion batteries.Nanoscale spectroscopic analysis on solid electrolytes plays a key role in bridging the gap between microstruct...Garnet-type oxide solid electrolytes are the critical materials for all-solid-state lithium ion batteries.Nanoscale spectroscopic analysis on solid electrolytes plays a key role in bridging the gap between microstructure and properties.In this work,Auger electron spectroscopy(AES),which can directly detect lithium element and distinguish its valence state,was applied to characterize the garnet-type Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6O12)(LLZTO).Different spectroscopy parameters were evaluated and optimal acquisition conditions were provided.Electron induced precipitation of lithium metal from LLZTO was observed.By exploring the influence factors of precipitation and combining transmission electron microscopy(TEM)and focused ion beam(FIB)experiments,the underlying mechanism of the phenomenon was revealed and previous controversy was resolved.The analysis method was also extended to other types of solid electrolytes,and this work provides a reference for future in-depth research on the structure-property relationship of solid electrolytes using AES.展开更多
Dual-active sites(DASs)catalysts have positive potential applications in broad fields because of their specific active sites and synergistic catalytic effects.Therefore,the controllable synthesis and finely regulating...Dual-active sites(DASs)catalysts have positive potential applications in broad fields because of their specific active sites and synergistic catalytic effects.Therefore,the controllable synthesis and finely regulating the activity of such catalysts has become a hot research area for now.In this work,we developed a pyrolysis-etching-hydrogen activation strategy to prepare the DASs catalysts involving single-atom Cu and B on N-doped porous carbon material(Cu_(1)-B/NPC).Numerous systematic characterization and density functional theoretical(DFT)calculation results showed that the Cu and B existed as Cu-N4 porphyrinlike unit and B-N_(3)unit in the obtained catalyst.DFT calculations further revealed that single-atom Cu and B sites were linked by bridging N atoms to form the Cu_(1)-B-N6 dual-sites.The Cu_(1)-B/NPC catalyst was more effective than the single-active site catalysts with B-N_(3)sites in NPC(B/NPC)and Cu-N4 porphyrin-like sites in NPC(Cu_(1)/NPC),respectively,for the dehydrogenative coupling of dimethylphenylsilane(DiMPSH)with various alcohols,performing the great activity(>99%)and selectivity(>99%).The catalytic performances of the Cu_(1)-B/NPC catalyst remained nearly unchanged after five cycles,also indicating its outstanding recyclability.DFT calculations showed that the Cu_(1)-B-N6 dual-sites exhibited the lowest energy profile on the potential energy surface than that of sole B-N_(3)and Cu-N4 porphyrin-like sites.Furthermore,the rate-limiting step of dehydrogenation of DiMPSH on Cu_(1)-B-N6 dual-sites also showed a much lower activation energy than the other two single sites.Benefitting from the superiority of the Cu_(1)-B-N6 dual-sites,the Cu_(1)-B/NPC catalyst can also be used for CO_(2)electroreduction to produce syngas.Thus,DASs catalysts are promising to achieve multifunctional catalytic properties and have aroused positive attention in the field of catalysis.展开更多
Ammonia plays a crucial role in agriculture and chemical engineering,and acts as a promising carbon-free transportation fuel.Catalysts design is deemed as a key to solve the restriction of energy-intensive Haber-Bosch...Ammonia plays a crucial role in agriculture and chemical engineering,and acts as a promising carbon-free transportation fuel.Catalysts design is deemed as a key to solve the restriction of energy-intensive Haber-Bosch process of ammonia production.With the development of computational modeling,computation-aided catalyst design serves as one important driving force for material innovation,saving a lot of experimental efforts based on trial and error.Computational modeling not only provides fundamental mechanistic insights into the reaction with great details regarding adsorbate geometries,electronic structures,and elementary-step energies,but also expedites the material discovery with descriptor-based catalyst design,core of which is the establishment of thermo/kinetic scaling relations.In this review,we present firstly the mechanistic understanding of ammonia synthesis and transition state scaling relations developed on pure transition-metal catalysts.We then summarize catalysts design strategies guided by alloy,size,and magnetic effects with the goal of breaking the limitations set by scaling relations to achieve better catalytic performance.Finally,future opportunities and challenges associated with computation design of optimal catalysts for ammonia synthesis are outlined.展开更多
The increasing penetration of plug-in electric ve- hicles (PEVs) has highlighted the importance of coordinating ubiquitous distributed energy resources (DERs) via the internet of things (IoT).With the help of vehicle-...The increasing penetration of plug-in electric ve- hicles (PEVs) has highlighted the importance of coordinating ubiquitous distributed energy resources (DERs) via the internet of things (IoT).With the help of vehicle-to-grid (V2G) technology, PEVs can be aggregated to behave as a storage system, yielding both economic and environmental benefits. In this paper, we propose an optimal bidding framework for a V2G-enabled re- gional energy internet (REI) to participate in day-ahead markets considering carbon trading. The REI operator aims to maximize the net profits from day-ahead markets while anticipating real- time adjustments. A detailed battery model is developed to depict the charging and discharging capability of V2G-enabled PEVs. A two-stage stochastic optimization model is formulated to schedule the operation of PEV fleets against various sources of uncertainties, e.g., the arrival and departure time of PEVs, solar power and real-time prices. Case studies undertaken based on realistic datasets demonstrate that the coordination of the V2G- enabled PEVs and other DERs can facilitate the accommodation of renewable energy, thus improving the REI’s revenues in energy and carbon markets.展开更多
All-solid-state lithium batteries(ASSLBs)have attracted great interest due to their promising energy density and strong safety.However,the interface issues,including large interfacial resistance between electrode and ...All-solid-state lithium batteries(ASSLBs)have attracted great interest due to their promising energy density and strong safety.However,the interface issues,including large interfacial resistance between electrode and electrolyte and low electrochemical stability of solid-state electrolytes against high-voltage cathodes,have restricted the development of high-voltage ASSLBs.Herein,we report an ASSLB with stable cycling by adopting a conformal polymer interlayer in-situ formed at the Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)–cathode interfaces.The polymer can perfectlyfill the voids and create a stable interface contact between LLZTO and cathodes.In addition,the electric field across the polymer interlayer is reduced compared with pure solid polymer electrolyte(SPE),which facilitates the electrochemical stability with high-voltage cathode.The all-solid-state Li|LLZTO-SPE|LiFe_(0.4)Mn_(0.6)PO_(4)(LMFP)cells achieve a low interface impedance,high specific capacity,and excellent cycling performance.This work presents an effective and practical strategy to rationally design the electrode–electrolyte interface for the application of high-voltage ASSLBs.展开更多
基金This paper is supported by Chinese NSF project(42130114)the strategic priority research program(B)of CAS(XDB41000000)the pre-research Project on Civil Aerospace Technologies No.D020202 funded by Chinese National Space Administration(CNSA)。
文摘It is well-known that the equilibrium isotope fractionation of mercury(Hg)includes classical massdependent fractionations(MDFs)and nuclear volume effect(NVE)induced mass-independent fractionations(MIFs).However,the effect of the NVE on these kinetic processes is not known.The total fractionations(MDFs+NVEinduced MIFs)of several representative Hg-incorporated substances were selected and calculated with ab initio calculations in this work for both equilibrium and kinetic processes.NVE-induced MIFs were calculated with scaled contact electron densities at the nucleus through systematic evaluations of their accuracy and errors using the Gaussian09 and DIRAC19 packages(named the electron density scaling method).Additionally,the NVE-induced kinetic isotope effect(KIE)of Hg isotopes are also calculated with this method for several representative Hg oxidation reactions by chlorine species.Total KIEs for 202 Hg/^(198)Hg ranging from−2.27‰to 0.96‰are obtained.Three anomalous^(202)Hg-enriched KIEs(δ^(202)Hg/^(198)Hg=0.83‰,0.94‰,and 0.96‰,)caused by the NVE are observed,which are quite different from the classical view(i.e.,light isotopes react faster than the heavy ones).The electron density scaling method we developed in this study can provide an easier way to calculate the NVE-induced KIEs for heavy isotopes and serve to better understand the fractionation mechanisms of mercury isotope systems.
文摘Using resting-state functional magnetic resonance imaging (fMRI) technology to assist in identifying brain diseases has great potential. In the identification of brain diseases, graph-based models have been widely used, where graph represents the similarity between patients or brain regions of interest. In these models, constructing high-quality graphs is of paramount importance. Researchers have proposed various methods for constructing graphs from different perspectives, among which the simplest and most popular one is Pearson Correlation (PC). Although existing methods have achieved significant results, these graphs are usually fixed once they are constructed, and are generally operated separately from downstream task. Such a separation may result in neither the constructed graph nor the extracted features being ideal. To solve this problem, we use the graph-optimized locality preserving projection algorithm to extract features and the population graph simultaneously, aiming in higher identification accuracy through a task-dependent automatic optimization of the graph. At the same time, we incorporate supervised information to enable more flexible modelling. Specifically, the proposed method first uses PC to construct graph as the initial feature for each subject. Then, the projection matrix and graph are iteratively optimized through graph-optimization locality preserving projections based on semi-supervised learning, which fully employs the knowledge in various transformation spaces. Finally, the obtained projection matrix is applied to construct the subject-level graph and perform classification using support vector machines. To verify the effectiveness of the proposed method, we conduct experiments to identify subjects with mild cognitive impairment (MCI) and Autism spectrum disorder (ASD) from normal controls (NCs), and the results showed that the classification performance of our method is better than that of the baseline method.
基金sponsored financially by the National Natural Science Foundation of China (No.21906104 and No.12175145)the Shanghai Rising-Star Program (21QA1406600).
文摘Photothermal catalysis realizes the synergistic effect of solar energy and thermochemistry,which also has the potential to improve the reaction rate and optimize the selectivity.In this review,the research progress of photothermal catalytic removal of volatile organic compounds(VOCs)by nano-catalysts in recent years is systematically reviewed.First,the fundamentals of photothermal catalysis and the fabrication of catalysts are described,and the design strategy of optimizing photothermal catalysis performance is proposed.Second,the performance for VOC degradation with photothermal catalysis is evaluated and compared for the batch and continuous systems.Particularly,the catalytic mechanism of VOC oxidation is systematically introduced based on experimental and theoretical study.Finally,the future limitations and challenges have been discussed,and potential research directions and priorities are highlighted.A broad view of recent photothermal catalyst fabrication,applications,challenges,and prospects can be systemically provided by this review.
基金supported by the Young Elite Scientists Sponsorship Program by CAST(2022QNRC001)National Key Research and Development Plan Project(2022YFD2301401)+4 种基金Outstanding Youth Science Fund Project of Natural Science Foundation of Jiangsu Province(BK20211576)the Central Government Guides Local Funds(ZYYD2023A13)Key Technology Research and Development Program of Hainan Province(ZDYF2022XDNY233)the China Postdoctoral Science Foundation(2018 M630564)a project funded by the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions.
文摘Germination,a powerful biofortification technique,holds immense potential in bolstering the micronutrient profile of essential staple grains,thereby paving the way for optimal nutritional enhancement.The primary goal of this study was to improve the technological functionality of germinated wheat flour by incorporating pentosanase(Pn)and glucose oxidase(Gox)enzymes,with particular emphasis on the evolutionary changes in its components.The inclusion of Gox did not produce any substantial impact on the volumetric characteristics of the steamed bread.The incorporation of Pn and Gox has been seen to enhance the overall excellence of steamed bread by optimizing loaf volume and textural characteristics while also improving the thermal stability of the dough.The existence of two endothermic peaks could be attributed to bound water or alterations in the granules within the starch crystallization region.Adding Pn and Gox reduced and increased the formation and stability time of the dough,respectively.A certain ratio was employed to assess alternations in the crystallinity of starch granules over a limited range.After steaming,a significant decrease in IR1047/1022 was observed,indicating that the elevated temperature partially disrupted the internal starch crystal structure,leading to a gelatinization reaction with water.The ratio of tensile resistance(R)and elongation(E)of dough increased significantly compared to the control.The results obtained from this study indicate that the simultaneous inclusion of enzymes(Pn+Gox)holds significant promise for expanding the technological functionality of germinated wheat flour dough and improving the quality attributes of steamed bread.
基金National Key Research and Development Program of China(2018YFC1708005)Applied Basic Research Project of Sichuan Province 2020(20YYJC3299)Fundamental Research Funds for the Central Universities(2020NGD01).
文摘[Objectives]This study aimed to optimize the ultrasonic-assisted extraction process of total flavonoids from a Zhuang medicine HERBA BLUMEAE RIPARIAE using response surface methodology.[Methods]Using rutin as a reference substance,a standard curve was drawn at a wavelength of 292 nm.Content determination was performed through absorbance under different conditions.The effects of ultrasonic time,ethanol volume fraction and liquid-to-solid ratio on the yield of total flavonoids from HERBA BLUMEAE RIPARIAE were investigated by single-factor tests.By using Box-Behnken test,the ultrasonic-assisted extraction process of total flavonoids from HERBA BLUMEAE RIPARIAE was optimized.[Results]The optimal extraction process of total flavonoids from HERBA BLUMEAE RIPARIAE was as follows:ultrasonic time of 30 min,ethanol volume fraction of 50%and liquid-to-solid ratio of 40∶1(mL/g).Under the optimal extraction conditions,the average yield of total flavonoids from HERBA BLUMEAE RIPARIAE was 85.47 mg/g.[Conclusions]The optimized extraction process was convenient and feasible.This study will provide a reference for the extraction of total flavonoids from HERBA BLUMEAE RIPARIAE,and provide certain guidance and basis for further development and utilization of the plan resource of Blumea riparia(Bl.)DC.
基金funding supports from the strategic priority research program (B) of Chinese Academy ofSciences (XDB18010104) and (XDB18010100)Chinese NSF Project (41490635)
文摘Understanding the origin of ocean island basalts(OIB) has important bearings on Earth's deep mantle.Although it is widely accepted that subducted oceanic crust, as a consequence of plate tectonics, contributes material to OIB's formation, its exact fraction in OIB's mantle source remains ambiguous largely due to uncertainties associated with existing geochemical proxies. Here we show, through theoretical calculation, that unlike many known proxies, triple oxygen isotope compositions(i.e.D^(17 )O) in olivine samples are not affected by crystallization and partial melting. This unique feature, therefore, allows olivine D^(17 )O values to identify subducted oceanic crusts in OIB's mantle source. Furthermore, the fractions of subducted ocean sediments and hydrothermally altered oceanic crust in OIB's mantle source can be quantified using their characteristic D^(17 )O values. Based on published D^(17 )O data, we estimated the fraction of subducted oceanic crust to be as high as 22.3% in certain OIB, but the affected region in the respective mantle plume is likely to be limited.
基金supported by the Strategic Priority Research Program(B)of CAS(XDB41000000)Pre-research Project on Civil Aerospace Technologies No.D020202 is funded by the Chinese National Space Administration(CNSA)and Chinese NSF projects(42130114)。
文摘With significant advances in mass spectrometry for isotope analysis in the last decade,e.g.,negative thermal ionization mass spectrometry and multi-collector inductively coupled plasma mass spectrometry,high-precision(ppm-level)measurements of tungsten(W)isotopes have been widely used for early earth differentiation processes,such as metal-silicate segregation,melting and crystallization processes during the magma ocean,and putative core-mantle exchange and dynamics.Here,we give a brief review of works on ^(182)W anomalies in terrestrial samples,including methods,results,explanations,implications,and prospects.The review will be presented by including the following parts:the introduction of W isotopes and the short-lived radioactive ^(182)Hf-^(182)W system;data notations and W isotope measurement methods;^(182)W anomalies observed in terrestrial samples;a summary of models developed for interpreting origins of positive and negative ^(182)W anomalies;future prospects.
基金the Strategic Priority Research Programme of Chinese Academy of Sciences(CAS)with grants XDA17040507 and QYZDJ-SSWSLH012the National Natural Science Foundation of China(NSFC,Grant Nos.12073073,1193300911973083 and U2031141)+2 种基金grants associated with the Yunling Scholar Project of Yunnan Provincethe Yunnan Province Scientist Workshop of Solar Physicsgrants 202101AT070018 and 2019FB005 associated with the Applied Basic Research of Yunnan Province。
文摘We attempt to model magnetic reconnection during the two-ribbon flare in a gravitationally stratified solar atmosphere with the Lundquist number of S=10~6 using 2 D simulations.We found that the tearing mode instability leads to inhomogeneous turbulence inside the reconnecting current sheet(CS)and invokes the fast phase of reconnection.Fast reconnection brings an extra dissipation of magnetic field which enhances the reconnection rate in an apparent way.The energy spectrum in the CS shows a power law pattern and the dynamics of plasmoids govern the associated spectral index.We noticed that the energy dissipation occurs at a scale l_(ko)of 100-200 km,and the associated CS thickness ranges from 1500 to 2500 km,which follows the Taylor scale l_(T)=l_(ko)S_(1/6).The termination shock(TS)appears in the turbulent region above flare loops,which is an important contributor to heating flare loops.Substantial magnetic energy is converted into both kinetic and thermal energies via TS,and the cumulative heating rate is greater than the rate of the kinetic energy transfer.In addition,the turbulence is somehow amplified by TS,in which the amplitude is related to the local geometry of the TS.
基金supported by the National Natural Science Foundation of China(No.8167090813).
文摘This study established a method for isolating large numbers of high-purity osteocytes from high-density bone.Bone fragments derived from mice tibia and femurs were alternately digested with type I collagenase and EDTA nine times,and the digested cells and bone chips(BC)were cultured,digested,and passaged when cells were fully grown.The types of cells obtained were identified by morphology,viable cell counts,alkaline phosphatase staining,and biochemical activity analyses,and specific osteocyte and osteoblast markers were evaluated by quantitative real-time polymerase chain reaction.Our results showed that among the cells obtained from the third digestion(fractions 7–9)of wild mice tibias and femurs and the remaining BCs,85%–90%of the cells were osteocytes.Moreover,their morphology was approximately one-tenth to one-fifth the size of osteoblasts,star-shaped or polygonal,with a dendritic structure,negative for alkaline phosphatase staining,and showed a high expression of dmp1 and sclerostin.Ninety percent of the cells in fractions 1–3 were osteoblasts,and were fusiform or polygonal shape.The activity of osteoblast-specific alkaline phosphatase and mRNA expression were high in this fraction,while the expression of osteocyte-specific dmp1 and sclerostin was not detected.In the second portion(fractions 4–6),a large number were osteoblasts,mixed with a small number of osteocytes,and had high alkaline phosphatase activity and osteocyte mRNA levels,a specific level of the osteocyte marker dmp1,and no sclerostin was detected.Osteocytes in daβcatot mice were also successfully isolated by this method,and we found that Wnt signaling increased the proliferation of these osteocytes.The proposed method can be used to culture osteocytes and osteoblasts of high purity and can be used for isolation and culture of these two kinds of cells from high-density bone,which provides an avenue for the study of osteocyte function in vitro.
文摘Purpose: Brain functional networks (BFNs) has become important approach for diagnosis of some neurological or psychological disorders. Before estimating BFN, obtaining blood oxygen level dependent (BOLD) representative signals from brain regions of interest (ROIs) is important. In the past decades, the common method is generally to take a ROI as a node, averaging all the voxel time series inside it to extract a representative signal. However, one node does not represent the entire information of this ROI, and averaging method often leads to signal cancellation and information loss. Inspired by this, we propose a novel model extraction method based on an assumption that a ROI can be represented by multiple nodes. Methods: In this paper, we first extract multiple nodes (the number is user-defined) from the ROI based on two traditional methods, including principal component analysis (PCA), and K-means (Clustering according to the spatial position of voxels). Then, canonical correlation analysis (CCA) was issued to construct BFNs by maximizing the correlation between the representative signals corresponding to the nodes in any two ROIs. Finally, to further verify the effectiveness of the proposed method, the estimated BFNs are applied to identify subjects with autism spectrum disorder (ASD) and mild cognitive impairment (MCI) from health controls (HCs). Results: Experimental results on two benchmark databases demonstrate that the proposed method outperforms the baseline method in the sense of classification performance. Conclusions: We propose a novel method for obtaining nodes of ROId based on the hypothesis that a ROI can be represented by multiple nodes, that is, to extract the node signals of ROIs with K-means or PCA. Then, CCA is used to construct BFNs.
基金supported financially by the National Natural Science Foundation of China(Nos.91961125 and 22002085)supported by the“Fundamental Research Funds for the Central Universities”(No.2018JBZ107)+4 种基金Guangdong Basic and Applied Basic Research Foundation(No.2020A1515110832)“Key Program for International S&T Cooperation Projects of China”from the Ministry of Science and Technology of China(No.2018YFE0124600)Chemistry and Chemical Engineering Guangdong Laboratory(No.1932004)Science and Technology Project of Guangdong Province(No.2020B0101370001)the Project from China Petrochemical Corporation(No.S20L00151).
文摘Designing catalyst to achieve ammonia synthesis at mild conditions is a meaningful challenge in catalysis community.Defective g-C_(3)N_(4)nanosheet supported single-cluster ruthenium and iron catalysts were investigated for their ammonia synthesis performance.Based on density functional theory(DFT)calculations and microkinetic simulations,Ru_(3)single-cluster anchored on defective g-C3N4 nanosheet(Ru_(3)/Nv-g-C_(3)N_(4))has a turnover frequency(TOF)5.8 times higher than the Ru(0001)step surface at industrial reaction conditions of 673 K and 100 bar for ammonia synthesis.In other words,similar TOFs could be achieved on Ru_(3)/Nv-g-C_(3)N_(4)at much milder conditions(623 K,30 bar)than on Ru(0001)(673 K,100 bar).Our computations reveal the reaction proceeds parallelly on Ru_(3)/Nv-g-C_(3)N_(4)through both dissociative and alternative associative mechanisms at typical reaction conditions(600–700 K,10–100 bar);N–N bond cleavage of*N2 and*NNH from the two respective pathways controls the reaction collectively.With increasing temperatures or decreasing pressures,the dissociative mechanism gradually prevails and associative mechanism recedes.In comparison,Fe_(3)/Nv-g-C_(3)N_(4)catalyst shows a much lower catalytic activity than Ru3/Nv-g-C_(3)N_(4)by two orders of magnitude and the reaction occurs solely through the dissociative pathway.The finding provides a prospective candidate and deepens the mechanistic understanding for ammonia synthesis catalyzed by single-cluster catalysts(SCCs).
基金supported by the Shanghai Science and Technology Plan(No.21DZ2260400)the startup funding from ShanghaiTech University.The electron microscopy characterization was supported by the Center for High-resolution Electron Microscopy(CћEM)at ShanghaiTech University。
文摘Garnet-type oxide solid electrolytes are the critical materials for all-solid-state lithium ion batteries.Nanoscale spectroscopic analysis on solid electrolytes plays a key role in bridging the gap between microstructure and properties.In this work,Auger electron spectroscopy(AES),which can directly detect lithium element and distinguish its valence state,was applied to characterize the garnet-type Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6O12)(LLZTO).Different spectroscopy parameters were evaluated and optimal acquisition conditions were provided.Electron induced precipitation of lithium metal from LLZTO was observed.By exploring the influence factors of precipitation and combining transmission electron microscopy(TEM)and focused ion beam(FIB)experiments,the underlying mechanism of the phenomenon was revealed and previous controversy was resolved.The analysis method was also extended to other types of solid electrolytes,and this work provides a reference for future in-depth research on the structure-property relationship of solid electrolytes using AES.
基金supported by the National Natural Science Foundation of China(Nos.51902003,22002085,21771003,21501004)the University Synergy Innovation Program of Anhui Province(No.GXXT-2021-020)+4 种基金the Anhui Province Natural Science Foundation(Nos.2108085QB71 and 2008085QB53)the Natural Science Research Project of Anhui Province Education Department(No.KJ2019A0581)the Open Project of Key Laboratory of Metallurgical Emission Reduction&Resources Recycling of Ministry of Education(No.JKF21-03)the Open Foundation of Anhui Laboratory of Clean Catalytic Engineering(No.LCCE-01)the Open Research Funds of Jiangxi Province Engineering Research Center of Ecological Chemical Industry(STKF2109).
文摘Dual-active sites(DASs)catalysts have positive potential applications in broad fields because of their specific active sites and synergistic catalytic effects.Therefore,the controllable synthesis and finely regulating the activity of such catalysts has become a hot research area for now.In this work,we developed a pyrolysis-etching-hydrogen activation strategy to prepare the DASs catalysts involving single-atom Cu and B on N-doped porous carbon material(Cu_(1)-B/NPC).Numerous systematic characterization and density functional theoretical(DFT)calculation results showed that the Cu and B existed as Cu-N4 porphyrinlike unit and B-N_(3)unit in the obtained catalyst.DFT calculations further revealed that single-atom Cu and B sites were linked by bridging N atoms to form the Cu_(1)-B-N6 dual-sites.The Cu_(1)-B/NPC catalyst was more effective than the single-active site catalysts with B-N_(3)sites in NPC(B/NPC)and Cu-N4 porphyrin-like sites in NPC(Cu_(1)/NPC),respectively,for the dehydrogenative coupling of dimethylphenylsilane(DiMPSH)with various alcohols,performing the great activity(>99%)and selectivity(>99%).The catalytic performances of the Cu_(1)-B/NPC catalyst remained nearly unchanged after five cycles,also indicating its outstanding recyclability.DFT calculations showed that the Cu_(1)-B-N6 dual-sites exhibited the lowest energy profile on the potential energy surface than that of sole B-N_(3)and Cu-N4 porphyrin-like sites.Furthermore,the rate-limiting step of dehydrogenation of DiMPSH on Cu_(1)-B-N6 dual-sites also showed a much lower activation energy than the other two single sites.Benefitting from the superiority of the Cu_(1)-B-N6 dual-sites,the Cu_(1)-B/NPC catalyst can also be used for CO_(2)electroreduction to produce syngas.Thus,DASs catalysts are promising to achieve multifunctional catalytic properties and have aroused positive attention in the field of catalysis.
基金This work was supported by the National Natural Science Foundation of China(Nos.91961125 and 22002085)This work was also supported by Guangdong Basic and Applied Basic Research Foundation(Nos.2020A1515110832 and 2023A1515012816)+2 种基金the“Fundamental Research Funds for the Central Universities”(No.2018JBZ107)“Key Program for International S&T Cooperation Projects of China”from the Ministry of Science and Technology of China(No.2018YFE0124600),Chemistry and Chemical Engineering Guangdong Laboratory(Nos.1932004 and 2011003),Science and Technology Project of Guangdong Province(No.2020B0101370001)the Project from China Petrochemical Corporation(No.S20L00151).
文摘Ammonia plays a crucial role in agriculture and chemical engineering,and acts as a promising carbon-free transportation fuel.Catalysts design is deemed as a key to solve the restriction of energy-intensive Haber-Bosch process of ammonia production.With the development of computational modeling,computation-aided catalyst design serves as one important driving force for material innovation,saving a lot of experimental efforts based on trial and error.Computational modeling not only provides fundamental mechanistic insights into the reaction with great details regarding adsorbate geometries,electronic structures,and elementary-step energies,but also expedites the material discovery with descriptor-based catalyst design,core of which is the establishment of thermo/kinetic scaling relations.In this review,we present firstly the mechanistic understanding of ammonia synthesis and transition state scaling relations developed on pure transition-metal catalysts.We then summarize catalysts design strategies guided by alloy,size,and magnetic effects with the goal of breaking the limitations set by scaling relations to achieve better catalytic performance.Finally,future opportunities and challenges associated with computation design of optimal catalysts for ammonia synthesis are outlined.
基金This work was supported in part by the Smart Grid Joint Foundation Program of the National Natural Science Foundation of China and the State Grid Corporation of China(U1866204)in part by the National Natural Science Foundation of China(51907064)and in part by the State Grid Corporation of China(Application Research and Trading Mechanism of Green Electricity Market toward Sustainable Energy Accommodation,52020119000G).
文摘The increasing penetration of plug-in electric ve- hicles (PEVs) has highlighted the importance of coordinating ubiquitous distributed energy resources (DERs) via the internet of things (IoT).With the help of vehicle-to-grid (V2G) technology, PEVs can be aggregated to behave as a storage system, yielding both economic and environmental benefits. In this paper, we propose an optimal bidding framework for a V2G-enabled re- gional energy internet (REI) to participate in day-ahead markets considering carbon trading. The REI operator aims to maximize the net profits from day-ahead markets while anticipating real- time adjustments. A detailed battery model is developed to depict the charging and discharging capability of V2G-enabled PEVs. A two-stage stochastic optimization model is formulated to schedule the operation of PEV fleets against various sources of uncertainties, e.g., the arrival and departure time of PEVs, solar power and real-time prices. Case studies undertaken based on realistic datasets demonstrate that the coordination of the V2G- enabled PEVs and other DERs can facilitate the accommodation of renewable energy, thus improving the REI’s revenues in energy and carbon markets.
基金Acknowledgements The authors acknowledge the financial support of the ability construction project of local Colleges and Universities in Shanghai （16070503000）, Special Fund of State Key Joint Laboratory of Environment Simulation and Pollution Control （16K10ESPCT）, Shanghai Gaofeng ＆ Gaoyuan Project for University Academic Program Development （A-9103- 15-065004）, and the United States National Science Foundation （0651794）.
基金support from National Key Research and Development Program of China(No.2019YFA0210600).
文摘All-solid-state lithium batteries(ASSLBs)have attracted great interest due to their promising energy density and strong safety.However,the interface issues,including large interfacial resistance between electrode and electrolyte and low electrochemical stability of solid-state electrolytes against high-voltage cathodes,have restricted the development of high-voltage ASSLBs.Herein,we report an ASSLB with stable cycling by adopting a conformal polymer interlayer in-situ formed at the Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)–cathode interfaces.The polymer can perfectlyfill the voids and create a stable interface contact between LLZTO and cathodes.In addition,the electric field across the polymer interlayer is reduced compared with pure solid polymer electrolyte(SPE),which facilitates the electrochemical stability with high-voltage cathode.The all-solid-state Li|LLZTO-SPE|LiFe_(0.4)Mn_(0.6)PO_(4)(LMFP)cells achieve a low interface impedance,high specific capacity,and excellent cycling performance.This work presents an effective and practical strategy to rationally design the electrode–electrolyte interface for the application of high-voltage ASSLBs.
