This study aimed to characterize and identify calcium-chelating peptides from rabbit bone collagen and explore the underlying chelating mechanism.Collagen peptides and calcium were extracted from rabbit bone by instan...This study aimed to characterize and identify calcium-chelating peptides from rabbit bone collagen and explore the underlying chelating mechanism.Collagen peptides and calcium were extracted from rabbit bone by instant ejection steam explosion(ICSE)combined with enzymatic hydrolysis,followed by chelation reaction to prepare rabbit bone peptide-calcium chelate(RBCP-Ca).The chelating sites were further analyzed by liquid chromatography-tandem mass(LC-MS/MS)spectrometry while the chelating mechanism and binding modes were investigated.The structural characterization revealed that RBCP successfully chelated with calcium ions.Furthermore,LC-MS/MS analysis indicated that the binding sites included both acidic amino acids(Asp and Glu)and basic amino acids(Lys and Arg),Interestingly,three binding modes,namely Inter-Linking,Loop-Linking and Mono-Linking were for the first time found,while Inter-Linking mode accounted for the highest proportion(75.1%),suggesting that chelation of calcium ions frequently occurred between two peptides.Overall,this study provides a theoretical basis for the elucidation of chelation mechanism of calcium-chelating peptides.展开更多
Western diet(rich in highly refined sugar and fat)can induce a range of metabolic dysfunctions in animals and humans,including neuroinflammation and cognitive function decline.Neuroinflammation and cognitive impairmen...Western diet(rich in highly refined sugar and fat)can induce a range of metabolic dysfunctions in animals and humans,including neuroinflammation and cognitive function decline.Neuroinflammation and cognitive impairment,two critical pathological characteristics of Alzheimer’s disease,have been closely associated with microbial alteration via the gut-brain axis.Thus,the present study aimed to investigate the influence of 2-O-β-D-glucopyranosyl-L-ascorbic acid(AA-2βG)isolated from the fruits of Lycium barbarum on preventing the high-fructose diet(HFrD)induced neuroinflammation in mice.It was found that AA-2βG prevented HFr D-induced cognitive deficits.AA-2βG also predominantly enhanced the gut barrier integrity,decreased lipopolysaccharide entry into the circulation,which subsequently countered the activation of glial cells and neuroinflammatory response.These beneficial effects were transmissible by horizontal fecal microbiome transplantation,transferring from AA-2βG fed mice to HFr D fed mice.Additionally,AA-2βG exerted neuroprotective effects involving the enrichment of Lactobacillus and Akkermansia,potentially beneficial intestinal bacteria.The present study provided the evidence that AA-2βG could improve indices of cognition and neuroinflammmation via modulating gut dybiosis and preventing leaky gut.As a potential functional food ingredient,AA-2βG may be applied to attenuate neuroinflammation associated with Western-style diets.展开更多
Lithium-sulfur(Li-S)batteries with lithium sulfide(Li2S)as cathode have attracted great attention recently,because of high specific capacity(1166 mA h g^-1)of Li2S and potential safety of using Li metal-free anode.Li2...Lithium-sulfur(Li-S)batteries with lithium sulfide(Li2S)as cathode have attracted great attention recently,because of high specific capacity(1166 mA h g^-1)of Li2S and potential safety of using Li metal-free anode.Li2S cathode has lower volume expansion and higher thermal stability than the traditional sulfur cathode.However,the problems of"shuttle effect"and poor electrical conductivity of the cathode material still need to be overcome.In this work,multi-layered Ti3C2/Li2S(ML-Ti3C2/Li2S)composite has been prepared and applied as a cathode in advanced Li-S batteries.The unique multi-layer sheet structure of Ti3 C2 provides space for the storage of Li2S,and its good conductivity greatly enhances the usage ratio of Li2 S and improves the conductivity of the whole Li2S cathode.Compared with commonly used graphene,ML-Ti3C2 can trap polysulfides effectively by chemical adsorption and also activate the reaction of Li2S to polysulfides by forming Ti-S bond.As a result,during the cycling of the batteries with ML-Ti3C2/Li2S cathodes,the activation voltage barrier of the first cycle has decreased to 2.8 V,and the"shuttle effect"has been suppressed effectively.The cycling and rate performances of the ML-Ti3C2/Li2S cathodes have been significantly improved compared to that of graphene/Li2 S cathodes.They maintain a capacity of 450 mAh g^-1 at 0.2 C after 100 cycles,and deliver attractive rate performances of 750,630,540,470 and 360 mAh g^-1 at 0.1 C,0.2 C,0.5 C,1 C,and 2 C,respectively.展开更多
The blockchain technology has been applied to wide areas.However,the open and transparent properties of the blockchains pose serious challenges to users’privacy.Among all the schemes for the privacy protection,the ze...The blockchain technology has been applied to wide areas.However,the open and transparent properties of the blockchains pose serious challenges to users’privacy.Among all the schemes for the privacy protection,the zero-knowledge proof algorithm conceals most of the private information in a transaction,while participants of the blockchain can validate this transaction without the private information.However,current schemes are only aimed at blockchains with the UTXO model,and only one type of assets circulates on these blockchains.Based on the zero-knowledge proof algorithm,this paper proposes a privacy protection scheme for blockchains that use the account and multi-asset model.We design the transaction structure,anonymous addresses and anonymous asset metadata,and also propose the methods of the asset transfer and double-spending detection.The zk-SNARKs algorithm is used to generate and to verify the zero-knowledge proof.And finally,we conduct the experiments to evaluate our scheme.展开更多
Polysaccharides from Fuzhuan brick tea(FBTPS),one of most important bioactive components in tea,showed various health-promoting functions.Our previous work demonstrated that the crude FBTPS(CFBTPS)could modulate the g...Polysaccharides from Fuzhuan brick tea(FBTPS),one of most important bioactive components in tea,showed various health-promoting functions.Our previous work demonstrated that the crude FBTPS(CFBTPS)could modulate the gut microbiota.However,which purified fraction in CFBTPS contributing to the modulation of gut microbiota remains unclear.Thus,the fermentation characteristics and probiotic activity of a purified fraction(FBTPS-2-1)of CFBTPS were evaluated in this work.The results showed that gut microbiota could utilize FBTPS-2-1 to produce short-chain fatty acids including acetic,propionic,n-butyric and n-valeric acids.FBTPS-2-1 could modulate the structure and metabolic pathways of gut microbiota.FBTPS-2-1 could increase the health-promoting gut microbiota such as Prevotellaceae and Bifidobacteriaceae,and decreased the harmful bacteria such as Enterobacteriaceae and Fusobacteriaceae.The results of metagenomics showed that Prevotella copri and Megamonas funiformis were the dominant bacteria after fermentation of FBTPS-2-1.Furthermore,FBTPS-2-1 could regulate the biosynthesis and metabolism pathways of gut microbiota.Thus,the enrichment of food with FBTPS-2-1 is expected as a potential strategy for promoting human health due to modulation of gut microbiota.展开更多
Compared with other secondary batteries,lithium-sulfur batteries(LSBs)have unparalleled advantages such as high energy density,low cost,etc.In liquid LSB systems,it is extremely easy to cause severe‘‘shuttle effecto...Compared with other secondary batteries,lithium-sulfur batteries(LSBs)have unparalleled advantages such as high energy density,low cost,etc.In liquid LSB systems,it is extremely easy to cause severe‘‘shuttle effecto and safety issues.Hence,the development of solid-state LSBs(SSLSBs)has been attracting much more attention.As the most essential part of the SSLSBs,the solid-state electrolyte(SSE)has received significant attention from researchers.In this review,we concentrate on discussing the core of SSLSBs,which is the SSE.Moreover,we also highlight the differences in the properties of the different SSEs,which are polymer-based electrolytes and ceramic-based electrolytes.In addition,the challenges and advances in different types of SSEs are also compared and described systematically.Furthermore,the prospects for new SSE systems and the design of effective SSE structures to achieve highperformance SSLSBs are also discussed.Thus,this review is expected to give readers a comprehensive and systematic understanding of SSEs for SSLSBs.展开更多
Perovskite materials have made a great progress in terms of the power conversion efficiency(PCE), rising from 3.8% to 25.2%. To obtain pinhole-free, superior crystal, and high-quality perovskite films with less defect...Perovskite materials have made a great progress in terms of the power conversion efficiency(PCE), rising from 3.8% to 25.2%. To obtain pinhole-free, superior crystal, and high-quality perovskite films with less defect, intermediates transformation is important, which has been clearly studied and widely applied.In this review, we systematically summarize the commonly formed intermediates and detailedly analyze their mechanisms from five aspects:(1) Solvent-induced intermediate;(2) HI-induced intermediate;(3)CH3NH2-induced intermediate;(4) MAAc-induced intermediate;(5) other intermediates. Finally, we also provide some prospects on high-quality perovskite fabrication based on using intermediates prudently.展开更多
Electrosynthesis of ammonia from the reduction of nitrogen is still confronted with the limited supply of gas reactant in dynamics as well as high activation barrier in thermodynamics.Unfortunately,despite tremendous ...Electrosynthesis of ammonia from the reduction of nitrogen is still confronted with the limited supply of gas reactant in dynamics as well as high activation barrier in thermodynamics.Unfortunately,despite tremendous efforts devoted to electrocatalysts themselves,they still fail to tackle the above two challenges simultaneously.Herein,we employ a heterogeneous catalyst adlayer-composed of crown ethers associated with Li^(+)ions-to achieve the dual promotion of dynamics and thermodynamics for ambient ammonia synthesis.Dynamically,the bound Li^(+)ions interact with the strong quadrupole moment of nitrogen,and trigger considerable reactant flux toward the catalyst.Thermodynamically,Li^(+)associated with the oxygen of crown ether achieves a higher density of states at the Fermi level for the catalyst,enabling effortless electron transfer from the catalysts to nitrogen and thus greatly reducing the activation barrier.As expected,the proof-of-concept system achieves an ammonia yield rate of 168.5μg h^(-1)mg^(-1)and a Faradaic efficiency of 75.3%at-0.3 V vs.RHE.This system-level approach opens up pathways for tackling the two key challenges that have limited the field of ammonia synthesis.展开更多
Polymeric organic battery materials are promising alternatives to the transition-metal-based ones owing to their enriched chemistries. However, the flammability of organic compounds brings in serious concern on batter...Polymeric organic battery materials are promising alternatives to the transition-metal-based ones owing to their enriched chemistries. However, the flammability of organic compounds brings in serious concern on battery safety. In addition to use flame-retarding electrolyte/electrolyte additives or battery separators,flame retardancy can readily be achieved through the integration of flame-retarding unit into the polymer backbone, imparting the flame retardancy permanently. The as-designed polymer based on phenothiazine shows significantly shortened self-extinguished time without deteriorating its intrinsic thermodynamic and electrochemical properties. Moreover, two electron per phenothiazine molecule is realized for the first time in a highly reversible manner with discharge voltages of 3.52 V and 4.16 V versus Li+/Li and an average capacity of ca. 120 mAh g-1 at a current rate of 2 C. The origin of the reversibility is investigated through density functional theory(DFT) calculations. These findings address the importance of molecular design for safer and more stable organic materials for batteries.展开更多
Glioblastoma(GBM) remains a formidable challenge in oncology.Chemodynamic therapy(CDT) that triggers tumor cell death by reactive oxygen species(ROS) could open up a new door for GBM treatment.Herein,we report a novel...Glioblastoma(GBM) remains a formidable challenge in oncology.Chemodynamic therapy(CDT) that triggers tumor cell death by reactive oxygen species(ROS) could open up a new door for GBM treatment.Herein,we report a novel CDT nanoagent.Hemoglobin(Hb)and glucose oxidase(GOx) were employed as powerful CDT catalysts.Instead of encapsulating the proteins in drug delivery nanocarriers,we formulate multimeric superstructures as self-delivery entities by crosslinking techniques.Red blood cell(RBC) membranes are camouflaged on the protein superstructures to promote the delivery across blood-brain barrier.The as-prepared RBC@Hb@GOx nanoparticles(NPs) offer superior biocompatibility,simplified structure,and high accumulation at the tumor site.We successfully demonstrated that the NPs could efficiently produce toxic ROS to kill U87 MG cancer cells in vitro and inhibit the growth of GBM tumor in vivo,suggesting that the new CDT nanoagent holds great promise for treating GBM.展开更多
It is of real and direct significance for China to cope with oil price fluctuations and ensure oil security. This paper aims to quantitatively analyze the specific contribution ratios of the complex factors influencin...It is of real and direct significance for China to cope with oil price fluctuations and ensure oil security. This paper aims to quantitatively analyze the specific contribution ratios of the complex factors influencing international crude oil prices and to establish crude oil price models to forecast long-term international crude oil prices. Six explanatory influential variables, namely Dow Jones Indexes, the Organization for Economic Cooperation and Development oil stocks, US rotary rig count, US dollar index, total open interest, which is the total number of outstanding contracts that are held by market participants at the end of each day, and geopolitical instability are specified, and the samples, from January 1990 to August 2017, are divided into six sub-periods. Moreover, the co-integration relationship among variables shows that the contribution ratios of all the variables influencing Brent crude oil prices are in accordance with the corresponding qualitative analysis. Furthermore, from September 2017 to December 2022 outside of the sample, the Vector Autoregressive forecasts show that annually averaged Brent crude oil prices for 2017-2022 would be $53.0, $61.3, $74.4, $90.0, $105.5, and $120.7 per barrel, respectively. The Vector Error Correction forecasts show that annual average Brent crude oil prices for 2017-2022 would be $53.0, $56.5, $58.5, $60.7, $63.0 and $65.4 per barrel, respectively.展开更多
Power system equipment outages are one of the most important factors affecting the reliability and economy of power systems.It is crucial to consider the reliability of the planning problems.In this paper,a generation...Power system equipment outages are one of the most important factors affecting the reliability and economy of power systems.It is crucial to consider the reliability of the planning problems.In this paper,a generation expansion planning(GEP)model is proposed,in which the candidate generating units and energy storage systems(ESSs)are simultaneously planned by minimizing the cost incurred on investment,operation,reserve,and reliability.The reliability cost is computed by multiplying the value of lost load(VOLL)with the expected energy not supplied(EENS),and this model makes a compromise between economy and reliability.Because the computation of EENS makes the major computation impediment of the entire model,a new efficient linear EENS formulation is proposed and applied in a multi-step GEP model.By doing so,the computation efficiency is significantly improved,and the solution accuracy is still desirable.The proposed GEP model is illustrated using the IEEE-RTS system to validate the effectiveness and superiority of the new model.展开更多
Artificial intelligence(AI)models are promising to improve the accuracy of wireless positioning systems,particularly in indoor environments where unpredictable radio propagation channel is a great challenge.Although g...Artificial intelligence(AI)models are promising to improve the accuracy of wireless positioning systems,particularly in indoor environments where unpredictable radio propagation channel is a great challenge.Although great efforts have been made to explore the effectiveness of different AI models,it is still an open problem whether these models,trained with the data collected from all base stations(BSs),could work when some BSs are unavailable.In this paper,we make the first effort to enhance the generalization ability of AI wireless positioning model to adapt to the scenario where only partial BSs work.Particularly,a Siamese Network based Wireless Positioning Model(SNWPM)is proposed to predict the location of mobile user equipment from channel state information(CSI)collected from 5G BSs.Furthermore,a Feature Aware Attention Module(FAAM)is introduced to reinforce the capability of feature extraction from CSI data.Experiments are conducted on the 2022 Wireless Communication AI Competition(WAIC)dataset.The proposed SNWPM achieves decimeter-level positioning accuracy even if the data of partial BSs are unavailable.Compared with other AI models,the proposed SNWPM can reduce the positioning error by nearly 50%to more than 60%while using less parameters and lower computation resources.展开更多
Memristor-based neuromorphic computing shows great potential for high-speed and high-throughput signal processing applications,such as electroencephalogram(EEG)signal processing.Nonetheless,the size of one-transistor ...Memristor-based neuromorphic computing shows great potential for high-speed and high-throughput signal processing applications,such as electroencephalogram(EEG)signal processing.Nonetheless,the size of one-transistor one-resistor(1T1R)memristor arrays is limited by the non-ideality of the devices,which prevents the hardware implementation of large and complex networks.In this work,we propose the depthwise separable convolution and bidirectional gate recurrent unit(DSC-BiGRU)network,a lightweight and highly robust hybrid neural network based on 1T1R arrays that enables efficient processing of EEG signals in the temporal,frequency and spatial domains by hybridizing DSC and BiGRU blocks.The network size is reduced and the network robustness is improved while ensuring the network classification accuracy.In the simulation,the measured non-idealities of the 1T1R array are brought into the network through statistical analysis.Compared with traditional convolutional networks,the network parameters are reduced by 95%and the network classification accuracy is improved by 21%at a 95%array yield rate and 5%tolerable error.This work demonstrates that lightweight and highly robust networks based on memristor arrays hold great promise for applications that rely on low consumption and high efficiency.展开更多
To determine the prevalence and clinical features of olfactory and taste disorders among coronavirus disease 2019(COVID-19)patients in China.A cross-sectional study was performed in Wuhan from April 3,2020 to April 15...To determine the prevalence and clinical features of olfactory and taste disorders among coronavirus disease 2019(COVID-19)patients in China.A cross-sectional study was performed in Wuhan from April 3,2020 to April 15,2020.A total of 187 patients with confirmed severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)completed face-to-face interviews or telephone follow-ups.We found that the prevalence of olfactory and taste disorders was significantly lower in the Chinese cohort than in foreign COVID-19 cohorts.Females were more prone to olfactory and taste disorders.In some patients,olfactory and taste disorders precede other symptoms and can be used as early screening and warning signs.展开更多
Abnormal voltages such as electrostatic,constant current,and strong electromagnetic signals can erroneously trigger operation of MEMS pyrotechnics and control systems in a fuze,which may result in casualties.This stud...Abnormal voltages such as electrostatic,constant current,and strong electromagnetic signals can erroneously trigger operation of MEMS pyrotechnics and control systems in a fuze,which may result in casualties.This study designs a solid-state micro-scale switch by combining the corona gas discharge theory of asymmetric electric fields and Peek’s Law.The MEMS switch can be transferred from“off”to“on”through the gas breakdown between the corona electrodes.In the model,one of the two electrodes is spherical and the other flat,so a non-uniform electric field is formed around the electrodes.The theoretical work is as follows.First,the relation among the radius of curvature of the spherical electrode,the discharge gap,and the air breakdown voltage is obtained;to meet the low voltage(30-60 V)required to drive the MEMS switch,the radius of curvature of the spherical electrode needs to be 10 e50 mm and the discharge gap between the two electrodes needs to be 9e11 mm.Second,the optimal ratioεis introduced to parameterize the model.Finally,the corona discharge structural parameters are determined by comparing the theoretical and electric field simulation results.The switch is then fabricated via MEMS processing.A hardware test platform is built and the performing chip tested.It is found that when the electrode gap is 9 mm,the electrostatic voltage is at least 37.3 V,with an error of 2.6%between the actual and theoretical air breakdown voltages.When the electrode gap is 11 mm,the electrostatic voltage is at least 42.3 V,with an error of 10.5%between the actual and theoretical air breakdown voltages.Both cases meet the design requirements.展开更多
An increase in the cache capacity is usually accompanied by a decrease in access speed.To balance the capacity and performance of caches,this paper proposes an instruction cache(ICache)architecture based on divide-by-...An increase in the cache capacity is usually accompanied by a decrease in access speed.To balance the capacity and performance of caches,this paper proposes an instruction cache(ICache)architecture based on divide-by-2 memory banks(D2MB-ICache).The control circuit and memory banks of D2MB-ICache work at the central processing unit(CPU)frequency and the divide-by-2 CPU frequency,respectively,so that the capacity of D2MB-ICache can be expanded without lowering its frequency.For sequential access,D2MB-ICache can output the required instruction from memory banks per CPU cycle by dividing the memory banks with a partition mechanism and employing an inversed clock technique.For non-sequential access,D2MB-ICache will fetch certain jump instructions one or two more times,so that it can catch the jump of the request address in time and send the correct instruction to the pipeline.Experimental results show that,compared with conventional ICache,D2MB-ICaches with the same and double capacities show a maximum frequency increase by an average of 14.6%and 6.8%,and a performance improvement by an average of 10.3%and 3.8%,respectively.Moreover,energy efficiency of 64-kB D2MB-ICache is improved by 24.3%.展开更多
基金granted by the National Key R&D Program of China (2021YFD21001005)National Natural Science Foundation of China (31972102,32101980)+1 种基金Special key project of Chongqing technology innovation and application development (cstc2021jscx-cylhX0014)Chongqing Technology Innovation and Application Development Special Project (cstc2021jscx-tpyzxX0014)。
文摘This study aimed to characterize and identify calcium-chelating peptides from rabbit bone collagen and explore the underlying chelating mechanism.Collagen peptides and calcium were extracted from rabbit bone by instant ejection steam explosion(ICSE)combined with enzymatic hydrolysis,followed by chelation reaction to prepare rabbit bone peptide-calcium chelate(RBCP-Ca).The chelating sites were further analyzed by liquid chromatography-tandem mass(LC-MS/MS)spectrometry while the chelating mechanism and binding modes were investigated.The structural characterization revealed that RBCP successfully chelated with calcium ions.Furthermore,LC-MS/MS analysis indicated that the binding sites included both acidic amino acids(Asp and Glu)and basic amino acids(Lys and Arg),Interestingly,three binding modes,namely Inter-Linking,Loop-Linking and Mono-Linking were for the first time found,while Inter-Linking mode accounted for the highest proportion(75.1%),suggesting that chelation of calcium ions frequently occurred between two peptides.Overall,this study provides a theoretical basis for the elucidation of chelation mechanism of calcium-chelating peptides.
基金the financial support from the Key Research and Development Program of Ningxia Hui Autonomous Region of China(2021BEF02008)the National Natural Science Foundation of China(32272330)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Western diet(rich in highly refined sugar and fat)can induce a range of metabolic dysfunctions in animals and humans,including neuroinflammation and cognitive function decline.Neuroinflammation and cognitive impairment,two critical pathological characteristics of Alzheimer’s disease,have been closely associated with microbial alteration via the gut-brain axis.Thus,the present study aimed to investigate the influence of 2-O-β-D-glucopyranosyl-L-ascorbic acid(AA-2βG)isolated from the fruits of Lycium barbarum on preventing the high-fructose diet(HFrD)induced neuroinflammation in mice.It was found that AA-2βG prevented HFr D-induced cognitive deficits.AA-2βG also predominantly enhanced the gut barrier integrity,decreased lipopolysaccharide entry into the circulation,which subsequently countered the activation of glial cells and neuroinflammatory response.These beneficial effects were transmissible by horizontal fecal microbiome transplantation,transferring from AA-2βG fed mice to HFr D fed mice.Additionally,AA-2βG exerted neuroprotective effects involving the enrichment of Lactobacillus and Akkermansia,potentially beneficial intestinal bacteria.The present study provided the evidence that AA-2βG could improve indices of cognition and neuroinflammmation via modulating gut dybiosis and preventing leaky gut.As a potential functional food ingredient,AA-2βG may be applied to attenuate neuroinflammation associated with Western-style diets.
基金financially supported by the National Natural Science Foundation of China(21606065,51372060,and 21676067)Anhui Provincial Natural Science Foundation(1708085QE98)+1 种基金the Fundamental Research Funds for the Central Universities(JZ2017HGTB0198,JZ2018HGBZ0138)the Opening Project of CAS Key Laboratory of Materials for Energy Conversion(KF2018003)
文摘Lithium-sulfur(Li-S)batteries with lithium sulfide(Li2S)as cathode have attracted great attention recently,because of high specific capacity(1166 mA h g^-1)of Li2S and potential safety of using Li metal-free anode.Li2S cathode has lower volume expansion and higher thermal stability than the traditional sulfur cathode.However,the problems of"shuttle effect"and poor electrical conductivity of the cathode material still need to be overcome.In this work,multi-layered Ti3C2/Li2S(ML-Ti3C2/Li2S)composite has been prepared and applied as a cathode in advanced Li-S batteries.The unique multi-layer sheet structure of Ti3 C2 provides space for the storage of Li2S,and its good conductivity greatly enhances the usage ratio of Li2 S and improves the conductivity of the whole Li2S cathode.Compared with commonly used graphene,ML-Ti3C2 can trap polysulfides effectively by chemical adsorption and also activate the reaction of Li2S to polysulfides by forming Ti-S bond.As a result,during the cycling of the batteries with ML-Ti3C2/Li2S cathodes,the activation voltage barrier of the first cycle has decreased to 2.8 V,and the"shuttle effect"has been suppressed effectively.The cycling and rate performances of the ML-Ti3C2/Li2S cathodes have been significantly improved compared to that of graphene/Li2 S cathodes.They maintain a capacity of 450 mAh g^-1 at 0.2 C after 100 cycles,and deliver attractive rate performances of 750,630,540,470 and 360 mAh g^-1 at 0.1 C,0.2 C,0.5 C,1 C,and 2 C,respectively.
基金supported by National Natural Science Foundation of China(61672499,61772502)Key Special Project of Beijing Municipal Science&Technology Commission(Z181100003218018)+1 种基金Natural Science Foundation of Inner Mongolia,Open Foundation of State key Laboratory of Networking and Switching Technology(Beijing University of Posts and Telecommunications,SKLNST-2016-2-09)SV-ICT Blockchain&DAPP Joint Lab
文摘The blockchain technology has been applied to wide areas.However,the open and transparent properties of the blockchains pose serious challenges to users’privacy.Among all the schemes for the privacy protection,the zero-knowledge proof algorithm conceals most of the private information in a transaction,while participants of the blockchain can validate this transaction without the private information.However,current schemes are only aimed at blockchains with the UTXO model,and only one type of assets circulates on these blockchains.Based on the zero-knowledge proof algorithm,this paper proposes a privacy protection scheme for blockchains that use the account and multi-asset model.We design the transaction structure,anonymous addresses and anonymous asset metadata,and also propose the methods of the asset transfer and double-spending detection.The zk-SNARKs algorithm is used to generate and to verify the zero-knowledge proof.And finally,we conduct the experiments to evaluate our scheme.
基金supported by the National Natural Science Foundation of China(No.32001645 and No.31972025)the National Key Research and Development Program of China(2018YFC1604404)the Fundamental Research Funds for the Central Universities(KJQN202154)。
文摘Polysaccharides from Fuzhuan brick tea(FBTPS),one of most important bioactive components in tea,showed various health-promoting functions.Our previous work demonstrated that the crude FBTPS(CFBTPS)could modulate the gut microbiota.However,which purified fraction in CFBTPS contributing to the modulation of gut microbiota remains unclear.Thus,the fermentation characteristics and probiotic activity of a purified fraction(FBTPS-2-1)of CFBTPS were evaluated in this work.The results showed that gut microbiota could utilize FBTPS-2-1 to produce short-chain fatty acids including acetic,propionic,n-butyric and n-valeric acids.FBTPS-2-1 could modulate the structure and metabolic pathways of gut microbiota.FBTPS-2-1 could increase the health-promoting gut microbiota such as Prevotellaceae and Bifidobacteriaceae,and decreased the harmful bacteria such as Enterobacteriaceae and Fusobacteriaceae.The results of metagenomics showed that Prevotella copri and Megamonas funiformis were the dominant bacteria after fermentation of FBTPS-2-1.Furthermore,FBTPS-2-1 could regulate the biosynthesis and metabolism pathways of gut microbiota.Thus,the enrichment of food with FBTPS-2-1 is expected as a potential strategy for promoting human health due to modulation of gut microbiota.
基金Financial support provided by the National Natural Science Foundation of China(21606065,52072105,21676067,51972093,U1910210,and U1810204)the Anhui Provincial Natural Science Foundation(1708085QE98 and 1908085QE178)+3 种基金the Fundamental Research Funds for the Central Universities(PA2021KCPY0028,PA2021GDGP0059,JZ2018HGBZ0138,JZ2020YYPY0109,and PA2020GDJQ0026)the Australian Research Council(ARC)Discovery Project(DP180101453)the Key Technologies Research and Development Program of Anhui Province(202104a05020044)the Major Science and Technology Projects in Anhui Province(2021e03020001 and 202003a05020014)。
文摘Compared with other secondary batteries,lithium-sulfur batteries(LSBs)have unparalleled advantages such as high energy density,low cost,etc.In liquid LSB systems,it is extremely easy to cause severe‘‘shuttle effecto and safety issues.Hence,the development of solid-state LSBs(SSLSBs)has been attracting much more attention.As the most essential part of the SSLSBs,the solid-state electrolyte(SSE)has received significant attention from researchers.In this review,we concentrate on discussing the core of SSLSBs,which is the SSE.Moreover,we also highlight the differences in the properties of the different SSEs,which are polymer-based electrolytes and ceramic-based electrolytes.In addition,the challenges and advances in different types of SSEs are also compared and described systematically.Furthermore,the prospects for new SSE systems and the design of effective SSE structures to achieve highperformance SSLSBs are also discussed.Thus,this review is expected to give readers a comprehensive and systematic understanding of SSEs for SSLSBs.
基金funded by the National Natural Science Foundation of China (51902148, 61704099, 51801088 and 11664001)the Fundamental Research Funds for the Central Universities (lzujbky-2020-61, lzujbky-2019-88 and lzujbky-2020-kb06)the Special Funding for Open and Shared Large-Scale Instruments and Equipments of Lanzhou University (LZU-GXJJ-2019C023 and LZU-GXJJ-2019C019)。
文摘Perovskite materials have made a great progress in terms of the power conversion efficiency(PCE), rising from 3.8% to 25.2%. To obtain pinhole-free, superior crystal, and high-quality perovskite films with less defect, intermediates transformation is important, which has been clearly studied and widely applied.In this review, we systematically summarize the commonly formed intermediates and detailedly analyze their mechanisms from five aspects:(1) Solvent-induced intermediate;(2) HI-induced intermediate;(3)CH3NH2-induced intermediate;(4) MAAc-induced intermediate;(5) other intermediates. Finally, we also provide some prospects on high-quality perovskite fabrication based on using intermediates prudently.
基金supported by the National Natural Science Foundation of China(U21A20332,52103226,52202275,52203314,and 12204253)the Distinguished Young Scholars Fund of Jiangsu Province(BK20220061)the Fellowship of China Postdoctoral Science Foundation(2021M702382)。
文摘Electrosynthesis of ammonia from the reduction of nitrogen is still confronted with the limited supply of gas reactant in dynamics as well as high activation barrier in thermodynamics.Unfortunately,despite tremendous efforts devoted to electrocatalysts themselves,they still fail to tackle the above two challenges simultaneously.Herein,we employ a heterogeneous catalyst adlayer-composed of crown ethers associated with Li^(+)ions-to achieve the dual promotion of dynamics and thermodynamics for ambient ammonia synthesis.Dynamically,the bound Li^(+)ions interact with the strong quadrupole moment of nitrogen,and trigger considerable reactant flux toward the catalyst.Thermodynamically,Li^(+)associated with the oxygen of crown ether achieves a higher density of states at the Fermi level for the catalyst,enabling effortless electron transfer from the catalysts to nitrogen and thus greatly reducing the activation barrier.As expected,the proof-of-concept system achieves an ammonia yield rate of 168.5μg h^(-1)mg^(-1)and a Faradaic efficiency of 75.3%at-0.3 V vs.RHE.This system-level approach opens up pathways for tackling the two key challenges that have limited the field of ammonia synthesis.
基金financial support from the National Natural Science Foundation of China (grant no.51772199)the Natural Science Foundation of Jiangsu Province (Grant no.BK20170329)+2 种基金the Collaborative Innovation Center of Suzhou Nano Science & Technologythe Priority Academic Program Development of Jiangsu Higher Education Institutionsthe 111 Project。
文摘Polymeric organic battery materials are promising alternatives to the transition-metal-based ones owing to their enriched chemistries. However, the flammability of organic compounds brings in serious concern on battery safety. In addition to use flame-retarding electrolyte/electrolyte additives or battery separators,flame retardancy can readily be achieved through the integration of flame-retarding unit into the polymer backbone, imparting the flame retardancy permanently. The as-designed polymer based on phenothiazine shows significantly shortened self-extinguished time without deteriorating its intrinsic thermodynamic and electrochemical properties. Moreover, two electron per phenothiazine molecule is realized for the first time in a highly reversible manner with discharge voltages of 3.52 V and 4.16 V versus Li+/Li and an average capacity of ca. 120 mAh g-1 at a current rate of 2 C. The origin of the reversibility is investigated through density functional theory(DFT) calculations. These findings address the importance of molecular design for safer and more stable organic materials for batteries.
基金supported by the Villum Fonden, Denmark, Project No. 13153the China Scholarship Council (CSC) for its generous support。
文摘Glioblastoma(GBM) remains a formidable challenge in oncology.Chemodynamic therapy(CDT) that triggers tumor cell death by reactive oxygen species(ROS) could open up a new door for GBM treatment.Herein,we report a novel CDT nanoagent.Hemoglobin(Hb)and glucose oxidase(GOx) were employed as powerful CDT catalysts.Instead of encapsulating the proteins in drug delivery nanocarriers,we formulate multimeric superstructures as self-delivery entities by crosslinking techniques.Red blood cell(RBC) membranes are camouflaged on the protein superstructures to promote the delivery across blood-brain barrier.The as-prepared RBC@Hb@GOx nanoparticles(NPs) offer superior biocompatibility,simplified structure,and high accumulation at the tumor site.We successfully demonstrated that the NPs could efficiently produce toxic ROS to kill U87 MG cancer cells in vitro and inhibit the growth of GBM tumor in vivo,suggesting that the new CDT nanoagent holds great promise for treating GBM.
基金supported by the National Science Foundation of China(NSFC No.41271551/71201157)the National Key Research and Development Program(2016YFA0602700)
文摘It is of real and direct significance for China to cope with oil price fluctuations and ensure oil security. This paper aims to quantitatively analyze the specific contribution ratios of the complex factors influencing international crude oil prices and to establish crude oil price models to forecast long-term international crude oil prices. Six explanatory influential variables, namely Dow Jones Indexes, the Organization for Economic Cooperation and Development oil stocks, US rotary rig count, US dollar index, total open interest, which is the total number of outstanding contracts that are held by market participants at the end of each day, and geopolitical instability are specified, and the samples, from January 1990 to August 2017, are divided into six sub-periods. Moreover, the co-integration relationship among variables shows that the contribution ratios of all the variables influencing Brent crude oil prices are in accordance with the corresponding qualitative analysis. Furthermore, from September 2017 to December 2022 outside of the sample, the Vector Autoregressive forecasts show that annually averaged Brent crude oil prices for 2017-2022 would be $53.0, $61.3, $74.4, $90.0, $105.5, and $120.7 per barrel, respectively. The Vector Error Correction forecasts show that annual average Brent crude oil prices for 2017-2022 would be $53.0, $56.5, $58.5, $60.7, $63.0 and $65.4 per barrel, respectively.
基金supported by project of State Grid Shandong Electric Power Company(52062520000Q)the National Key Research and Development Program of China(2019YFE0118400)。
文摘Power system equipment outages are one of the most important factors affecting the reliability and economy of power systems.It is crucial to consider the reliability of the planning problems.In this paper,a generation expansion planning(GEP)model is proposed,in which the candidate generating units and energy storage systems(ESSs)are simultaneously planned by minimizing the cost incurred on investment,operation,reserve,and reliability.The reliability cost is computed by multiplying the value of lost load(VOLL)with the expected energy not supplied(EENS),and this model makes a compromise between economy and reliability.Because the computation of EENS makes the major computation impediment of the entire model,a new efficient linear EENS formulation is proposed and applied in a multi-step GEP model.By doing so,the computation efficiency is significantly improved,and the solution accuracy is still desirable.The proposed GEP model is illustrated using the IEEE-RTS system to validate the effectiveness and superiority of the new model.
基金supported by National Natural Science Foundation of China (No. 62076251)sponsored by IMT-2020(5G) Promotion Group 5G+AI Work Group+3 种基金jointly sponsored by China Academy of Information and Communications TechnologyGuangdong OPPO Mobile Telecommunications Corp., Ltdvivo Mobile Communication Co., LtdHuawei Technologies Co., Ltd
文摘Artificial intelligence(AI)models are promising to improve the accuracy of wireless positioning systems,particularly in indoor environments where unpredictable radio propagation channel is a great challenge.Although great efforts have been made to explore the effectiveness of different AI models,it is still an open problem whether these models,trained with the data collected from all base stations(BSs),could work when some BSs are unavailable.In this paper,we make the first effort to enhance the generalization ability of AI wireless positioning model to adapt to the scenario where only partial BSs work.Particularly,a Siamese Network based Wireless Positioning Model(SNWPM)is proposed to predict the location of mobile user equipment from channel state information(CSI)collected from 5G BSs.Furthermore,a Feature Aware Attention Module(FAAM)is introduced to reinforce the capability of feature extraction from CSI data.Experiments are conducted on the 2022 Wireless Communication AI Competition(WAIC)dataset.The proposed SNWPM achieves decimeter-level positioning accuracy even if the data of partial BSs are unavailable.Compared with other AI models,the proposed SNWPM can reduce the positioning error by nearly 50%to more than 60%while using less parameters and lower computation resources.
基金Project supported by the National Key Research and Development Program of China(Grant No.2019YFB2205102)the National Natural Science Foundation of China(Grant Nos.61974164,62074166,61804181,62004219,62004220,and 62104256).
文摘Memristor-based neuromorphic computing shows great potential for high-speed and high-throughput signal processing applications,such as electroencephalogram(EEG)signal processing.Nonetheless,the size of one-transistor one-resistor(1T1R)memristor arrays is limited by the non-ideality of the devices,which prevents the hardware implementation of large and complex networks.In this work,we propose the depthwise separable convolution and bidirectional gate recurrent unit(DSC-BiGRU)network,a lightweight and highly robust hybrid neural network based on 1T1R arrays that enables efficient processing of EEG signals in the temporal,frequency and spatial domains by hybridizing DSC and BiGRU blocks.The network size is reduced and the network robustness is improved while ensuring the network classification accuracy.In the simulation,the measured non-idealities of the 1T1R array are brought into the network through statistical analysis.Compared with traditional convolutional networks,the network parameters are reduced by 95%and the network classification accuracy is improved by 21%at a 95%array yield rate and 5%tolerable error.This work demonstrates that lightweight and highly robust networks based on memristor arrays hold great promise for applications that rely on low consumption and high efficiency.
基金supported in part by the National Natural Science Foundation of China(81830064,81721092,81971841)the National Key Research and Development Plan(2017YFC1103304,2017YFC1104701)。
文摘To determine the prevalence and clinical features of olfactory and taste disorders among coronavirus disease 2019(COVID-19)patients in China.A cross-sectional study was performed in Wuhan from April 3,2020 to April 15,2020.A total of 187 patients with confirmed severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)completed face-to-face interviews or telephone follow-ups.We found that the prevalence of olfactory and taste disorders was significantly lower in the Chinese cohort than in foreign COVID-19 cohorts.Females were more prone to olfactory and taste disorders.In some patients,olfactory and taste disorders precede other symptoms and can be used as early screening and warning signs.
文摘Abnormal voltages such as electrostatic,constant current,and strong electromagnetic signals can erroneously trigger operation of MEMS pyrotechnics and control systems in a fuze,which may result in casualties.This study designs a solid-state micro-scale switch by combining the corona gas discharge theory of asymmetric electric fields and Peek’s Law.The MEMS switch can be transferred from“off”to“on”through the gas breakdown between the corona electrodes.In the model,one of the two electrodes is spherical and the other flat,so a non-uniform electric field is formed around the electrodes.The theoretical work is as follows.First,the relation among the radius of curvature of the spherical electrode,the discharge gap,and the air breakdown voltage is obtained;to meet the low voltage(30-60 V)required to drive the MEMS switch,the radius of curvature of the spherical electrode needs to be 10 e50 mm and the discharge gap between the two electrodes needs to be 9e11 mm.Second,the optimal ratioεis introduced to parameterize the model.Finally,the corona discharge structural parameters are determined by comparing the theoretical and electric field simulation results.The switch is then fabricated via MEMS processing.A hardware test platform is built and the performing chip tested.It is found that when the electrode gap is 9 mm,the electrostatic voltage is at least 37.3 V,with an error of 2.6%between the actual and theoretical air breakdown voltages.When the electrode gap is 11 mm,the electrostatic voltage is at least 42.3 V,with an error of 10.5%between the actual and theoretical air breakdown voltages.Both cases meet the design requirements.
基金the Postgraduate Research Innovation Program of Jiangsu Province under Grant No.KYCX20_1936the Fundamental Research Funds for the Central Universities under Grant No.JUSRP51510the Key Research and Development Program of Jiangsu under Grant No.BE2019003-2.
文摘An increase in the cache capacity is usually accompanied by a decrease in access speed.To balance the capacity and performance of caches,this paper proposes an instruction cache(ICache)architecture based on divide-by-2 memory banks(D2MB-ICache).The control circuit and memory banks of D2MB-ICache work at the central processing unit(CPU)frequency and the divide-by-2 CPU frequency,respectively,so that the capacity of D2MB-ICache can be expanded without lowering its frequency.For sequential access,D2MB-ICache can output the required instruction from memory banks per CPU cycle by dividing the memory banks with a partition mechanism and employing an inversed clock technique.For non-sequential access,D2MB-ICache will fetch certain jump instructions one or two more times,so that it can catch the jump of the request address in time and send the correct instruction to the pipeline.Experimental results show that,compared with conventional ICache,D2MB-ICaches with the same and double capacities show a maximum frequency increase by an average of 14.6%and 6.8%,and a performance improvement by an average of 10.3%and 3.8%,respectively.Moreover,energy efficiency of 64-kB D2MB-ICache is improved by 24.3%.
