Objective This study aimed to explore the spatial heterogeneity and risk factors for dental caries in 12-year-old children in Shanxi province,China.Methods The data encompassed 3,721 participants from the two most rec...Objective This study aimed to explore the spatial heterogeneity and risk factors for dental caries in 12-year-old children in Shanxi province,China.Methods The data encompassed 3,721 participants from the two most recent oral health surveys conducted across 16 districts in Shanxi Province in 2015 and 2018.Eighteen specific variables were analyzed to examine the interplay between socioeconomic factors,medical resources and environmental conditions.The Geo-detector model was employed to assess the impacts and interactions of these ecological factors.Results Socioeconomic factors(Q=0.30,P<0.05)exhibited a more substantial impact compared to environmental(Q=0.19,P<0.05)and medical resource factors(Q=0.25,P<0.05).Notably,the urban population percentage(UPP)demonstrated the most significant explanatory power for the spatial heterogeneity in caries prevalence,as denoted by its highest q-value(q=0.51,P<0.05).Additionally,the spatial distribution’s heterogeneity of caries was significantly affected by SO2 concentration(q=0.39,P<0.05)and water fluoride levels(q=0.27,P<0.05)among environmental factors.Conclusion The prevalence of caries exhibited spatial heterogeneity,escalating from North to South in Shanxi Province,China,influenced by socioeconomic factors,medical resources,and environmental conditions to varying extents.展开更多
The occurrence of benign prostate hyperplasia(BPH)was related to disrupted sex steroid hormones,and metformin(Met)had a clinical response to sex steroid hormone-related gynaecological disease.However,whether Met exert...The occurrence of benign prostate hyperplasia(BPH)was related to disrupted sex steroid hormones,and metformin(Met)had a clinical response to sex steroid hormone-related gynaecological disease.However,whether Met exerts an antiproliferative effect on BPH via sex steroid hormones remains unclear.Here,our clinical study showed that along with prostatic epithelial cell(PEC)proliferation,sex steroid hormones were dysregulated in the serum and prostate of BPH patients.As the major contributor to dysregulated sex steroid hormones,elevated dihydrotestosterone(DHT)had a significant positive relationship with the clinical characteristics of BPH patients.Activation of adenosine 5'-monophosphate(AMP)-activated protein kinase(AMPK)by Met restored dysregulated sex steroid hormone homeostasis and exerted antiproliferative effects against DHT-induced proliferation by inhibiting the formation of androgen receptor(AR)-mediated Yes-associated protein(YAP1)-TEA domain transcription factor(TEAD4)heterodimers.Met’s anti-proliferative effects were blocked by AMPK inhibitor or YAP1 overexpression in DHT-cultured BPH-1 cells.Our findings indicated that Met would be a promising clinical therapeutic approach for BPH by inhibiting dysregulated steroid hormone-induced PEC proliferation.展开更多
Objective:This study aimed to estimate the incidence rate and clinical characteristics of inflammatory bowel disease(IBD)in the Chinese population,specially comparing the North and South regions.Methods:We designed a ...Objective:This study aimed to estimate the incidence rate and clinical characteristics of inflammatory bowel disease(IBD)in the Chinese population,specially comparing the North and South regions.Methods:We designed a questionnaire survey for patients diagnosed with IBD and conducted a systematic literature search in PubMed,China National Knowledge Internet,and Wanfang digital database,covering studies published between 2012 and 2022.Meta-analysis was performed to determine the overall incidence rate and prevalence of clinical manifestations of Crohn's disease(CD)and ulcerative colitis(UC)in China's Mainland.Clinical phenotypes and demographic characteristics were calculated with 95%confidence intervals(CI).A comparison between the northern and southern regions was also conducted.Results:The questionnaire survey included 440 patients,and 64 publications were included for Meta-analysis.The overall incidence rates of IBD,CD,and UC were 1.36(95%CI:0.79-2.33)per 100,000 person-years,0.23(95%CI:0.09-0.58)per 100,000 person-years,and 1.12(95%CI:0.69-1.80)per 100,000 person-years,respectively.The incidence rates of IBD,CD,and UC were all higher in southern China compared to the North.Clinical characteristics of 440 IBD patients from the questionnaire and 2,821 CD patients and 12,809 UC patients from the literature were analyzed.There were more male patients compared to female patients.CD cases in the North exhibited earlier disease diagnosis(P<0.01),more upper gastrointestinal lesions(P<0.01),and higher hospitalizations rates(P<0.01)compared to the South.UC cases in the North had higher severity(P<0.01),anemia rates(P<0.01),and weight loss(P<0.01)compared to the South.Conclusions:The incidence rates of IBD,CD,and UC were higher in southern China than in the North.Northern patients exhibited more severe symptoms compared to their southern counterparts.展开更多
High-voltage LiCoO_(2)(LCO) is an attractive cathode for ultra-high energy density lithium-ion batteries(LIBs) in the 3 C markets.However,the sluggish lithium-ion diffusion at high voltage significantly hampers its ra...High-voltage LiCoO_(2)(LCO) is an attractive cathode for ultra-high energy density lithium-ion batteries(LIBs) in the 3 C markets.However,the sluggish lithium-ion diffusion at high voltage significantly hampers its rate capability.Herein,combining experiments with density functional theory(DFT) calculations,we demonstrate that the kinetic limitations can be mitigated by a facial Mg^(2+)+Gd^(3+)co-doping method.The as-prepared LCO shows significantly enhanced Li-ion diffusion mobility at high voltage,making more homogenous Li-ion de/intercalation at a high-rate charge/discharge process.The homogeneity enables the structural stability of LCO at a high-rate current density,inhibiting stress accumulation and irreversible phase transition.When used in combination with a Li metal anode,the doped LCO shows an extreme fast charging(XFC) capability,with a superior high capacity of 193.1 mAh g^(-1)even at the current density of 20 C and high-rate capacity retention of 91.3% after 100 cycles at 5 C.This work provides a new insight to prepare XFC high-voltage LCO cathode materials.展开更多
Bimetallic Pt-skin catalyst is a class of near-surface alloy(NSA)that owns a high degree of control over composition.Herein,density functional theory(DFT)is used to calculate the energetics of oxygen reduction reactio...Bimetallic Pt-skin catalyst is a class of near-surface alloy(NSA)that owns a high degree of control over composition.Herein,density functional theory(DFT)is used to calculate the energetics of oxygen reduction reaction(ORR)on Pt-skin over Ir,Pd and Au substrates.A Brønsted-Evans-Polanyi(BEP)relationship can be determined for the oxygen molecule dissociation.The binding energy of both atomic oxygen and hydroxyl radical is found to correlate well with the d band center of Pt-skin atoms.Their catalytic activities show the volcano relationship as the positions of each substrate in the periodic table.The effect of surface strain,band structure and charge transfer on the d band center is well studied,and it can be found that the surface strain effect plays a dominant role for all Pt-skin catalysts.Ir substrate makes the d band center of Pt-skin go far away from the Fermi level,while Au substrate makes it move towards the Fermi level.Being different from both Ir and Au,Pd substrate makes the d band center of Pt-skin comparable with the monometallic Pt.展开更多
Sulfur and selenium have been paid more and more attention in energy storage systems because of their high theoretical specific gravimetric and volumetric capacities.With the increasing scarcity of lithium resources,s...Sulfur and selenium have been paid more and more attention in energy storage systems because of their high theoretical specific gravimetric and volumetric capacities.With the increasing scarcity of lithium resources,secondary batteries made of sulfur and selenium coupled with other alkali metal/alkaline earth metals(e.g.Na,K,Mg)are expected to play a vital role in future production and human life.Due to the volume expansion,poor conductivity and shuttle effect,the structure design of cathode,as one of the important roles in metal-S/Se batteries,has always been a hot and difficult point.In the review,various host materials of S and Se are clarified and discussed.Typically,carbonaceous materials are the most widely used hosts,while polar materials are becoming more and more popular in metal-S/Se batteries.Through a comprehensive overview,it is hoped that previous research experiences can provide further reference and guidance for the sustainable development of metal-S/Se batteries.展开更多
锌-空气电池(ZAB)因其能量密度高、环境友好、成本低以及安全性高而备受关注.然而,空气电极上的氧还原反应(ORR)动力学缓慢,严重限制了ZAB的输出功率.尽管铂基催化剂展现出优异的ORR催化活性,但高昂的成本制约其大规模商业化应用.因此,...锌-空气电池(ZAB)因其能量密度高、环境友好、成本低以及安全性高而备受关注.然而,空气电极上的氧还原反应(ORR)动力学缓慢,严重限制了ZAB的输出功率.尽管铂基催化剂展现出优异的ORR催化活性,但高昂的成本制约其大规模商业化应用.因此,迫切需要开发高效、低成本的ORR电催化剂.研究表明,具有原子分散Co-N4活性位点的Co-N-C单原子催化剂是理想的ORR非贵金属催化剂,但其仍然存在与反应关键中间体结合能较高的难题.目前的研究主要通过调控单原子配位环境与增大活性位点密度来提高Co-N-C催化剂的活性,但如何精确控制中心金属电子结构以及避免高温下金属原子的团聚仍面临巨大挑战.除了单原子活性位点外,催化剂载体的键合结构、电荷分布状态亦会影响载体本身和单原子位点的催化活性.然而,现有的研究主要聚焦于单原子位点或无金属催化剂单方面活性的提升,关于它们之间的相互作用对于催化性能影响的研究相对很少.为了进一步提高Co单原子催化剂的催化活性,本文通过简单的模板法与NH3二次处理策略制备了氮掺杂缺陷碳负载的Co-N_(5)位点单原子催化剂.电感耦合等离子体发射光谱结果表明,单原子Co的金属负载量高达2.57 wt%.此外,相比于未经过NH3二次处理的Co-Nx/HC样品,Co-N_(5)/DHC样品在电子顺磁共振谱中g=2.003处呈现出更明显的共振信号,在C 1s高分辨谱中具有更低的C-C(sp2杂化)/C-N(sp3杂化)比例以及明显增加的吡啶氮信号,证实了Co-N_(5)/DHC显著提升的氮掺杂碳缺陷浓度并具有丰富的边界/缺陷位点.同时,X射线吸收谱与球差矫正透射电子显微镜结果表明所制备的样品为原子分散的Co-N_(5)结构,从而证明成功制备了缺陷氮掺杂碳耦合Co-N_(5)位点单原子催化剂.电化学测试结果表明,缺陷氮掺杂碳耦合Co-N_(5)位点后表现较好的ORR性能,半波电位达到0.877 V,明显高于Co-Nx/HC对比样品和商业化Pt/C催化剂.Koutecky-Levich曲线和旋转盘环电极测试结果表明,Co-N_(5)/DHC催化剂的高效4e-反应路径.且在10000次的加速老化测试中,Co-N_(5)/DHC半波电位仅降低了7 m V,稳定性优于Pt/C.以Co-N_(5)/DHC为阴极催化剂组装的ZAB开路电压为1.45 V,峰值输出功率密度能够达到160.7 m W cm^(-2),并能提供766.2 m A h gZn-1的比容量,展现出较高的应用前景.密度泛函理论计算表明,Co-N_(5)位点与缺陷氮掺杂碳的相互作用诱导Co中心位点电子的重新分布,降低了ORR反应能垒.综上,本文为设计与合成高性能的Co单原子催化剂,用于先进的可再生能源转换系统提供了一种新思路.展开更多
Understanding alkali metal ions’(e.g.,Li^(+)/Na^(+)/K^(+))transport mechanism is challenging but critical to improving the performance of alkali metal batteries.Herein using a-MnO_(2)nanowires as cathodes,the transpo...Understanding alkali metal ions’(e.g.,Li^(+)/Na^(+)/K^(+))transport mechanism is challenging but critical to improving the performance of alkali metal batteries.Herein using a-MnO_(2)nanowires as cathodes,the transport kinetics of Li^(+)/Na^(+)/K^(+)in the 2×2 channels of a-MnO_(2)with a growth direction of[001]is revealed.We show that ion radius plays a decisive role in determining the ion transport and electrochemistry.Regardless of the ion radii,Li^(+)/Na^(+)/K^(+)can all go through the 2×2 channels of a-MnO_(2),generating large stress and causing channel merging or opening.However,smaller ions such as Li^(+)and Na^(+)cannot only transport along the[001]direction but also migrate along the<110>direction to the nanowire surface;for large ion such as K^(+),diffusion along the<110>direction is prohibited.The different ion transport behavior has grand consequences in the electrochemistry of metal oxygen batteries(MOBs).For Li-O_(2)battery,Li^(+)transports uniformly to the nanowire surface,forming a uniform layer of oxide;Na^(+)also transports to the nanowire surface but may be clogged locally due to its larger radius,therefore sporadic pearl-like oxides form on the nanowire surface;K^(+)cannot transport to the nanowire surface due to its large radius,instead,it breaks the nanowire locally,causing local deposition of potassium oxides.The study provides atomic scale understanding of the alkali metal ion transport mechanism which may be harnessed to improve the performance of MOBs.展开更多
The geochemical characteristics and potential controlling factors of colloidal Zn,Cd,and Pb in Huanghe(Yellow)River estuary(HRE),China were investigated.The three metals were highly variable over a range of spatiotemp...The geochemical characteristics and potential controlling factors of colloidal Zn,Cd,and Pb in Huanghe(Yellow)River estuary(HRE),China were investigated.The three metals were highly variable over a range of spatiotemporal scales,comprehensively forced by various physical and biological processes.Total dissolved Zn,Cd,and Pb varied from 200.1 to 321.7,2.6 to 4.1,and 0.5 to 1.0 nmol/L,respectively.Only one near-estuarine station of Zn had contamination factor values>1,which indicate the lower contaminant levels.Five dissolved species of Zn,Cd and Pb were fractionated,namely<1 kDa,1-3 kDa,3-10 kDa,10-100 kDa,and 100 kDa-0.45μm.The<1 kDa truly dissolved phase was the main fraction of the three dissolved metals(50%-62%),while the 100-kDa-0.45-μm high molecular weight colloidal fraction was dominant in their respective colloidal phase.Territorial input and sediment acted as important sources of strong ligands and natural colloids for the HRE water system.<3-kDa Zn and Pb were susceptible to the dissolved oxygen,the behaviors of colloidal Zn and 3-10-kDa Pb were related to dissolved organic carbon(DOC).However,no significant correlation between each dissolved fraction of Cd and salinity,pH,temperature,colloidal organic carbon,and DOC was found in this study.Overall,these findings,completed by the evaluation of the dissolved species of Zn,Cd,and Pb at 10 sites over the river-sea mixing zone,provided new insights into the colloidal heterogeneity that affect metals geochemical features,migration and fate in estuaries.展开更多
Although vaccines have been developed,mutations of SARS-CoV-2,especially the dominant B.1.617.2(delta)and B.1.529(omicron)strains with more than 30 mutations on their spike protein,have caused a significant decline in...Although vaccines have been developed,mutations of SARS-CoV-2,especially the dominant B.1.617.2(delta)and B.1.529(omicron)strains with more than 30 mutations on their spike protein,have caused a significant decline in prophylaxis,calling for the need for drug improvement.Antibodies are drugs preferentially used in infectious diseases and are easy to get from immunized organisms.The current study combined molecular modeling and single memory B cell sequencing to assess candidate sequences before experiments,providing a strategy for the fabrication of SARS-CoV-2 neutralizing antibodies.A total of 128 sequences were obtained after sequencing 196 memory B cells,and 42 sequences were left after merging extremely similar ones and discarding incomplete ones,followed by homology modeling of the antibody variable region.Thirteen candidate sequences were expressed,of which three were tested positive for receptor binding domain recognition but only one was confirmed as having broad neutralization against several SARS-CoV-2 variants.The current study successfully obtained a SARS-CoV-2 antibody with broad neutralizing abilities and provided a strategy for antibody development in emerging infectious diseases using single memory B cell BCR sequencing and computer assistance in antibody fabrication.展开更多
Background:The plant-growth-promoting rhizobacterium Tsukamurella tyrosinosolvens is a rare strain of actinomycete,in order to recognize and expand the ecological functions of rare actinomycetes.Methods:In this experi...Background:The plant-growth-promoting rhizobacterium Tsukamurella tyrosinosolvens is a rare strain of actinomycete,in order to recognize and expand the ecological functions of rare actinomycetes.Methods:In this experiment,we studied the effect of Tsukamurella tyrosinosolvens P9 on the drought resistance of peanut by inoculating peanut seedlings in pots and measuring the growth and physiological indicators of peanut under drought stress and re-watering conditions.Results:The results showed that during drought stress,the relative water content of the soil and leaves,chlorophyll content,and stomatal length,width,and aperture were significantly decreased while the levels of malondialdehyde(MDA),H_(2)O_(2) and stomatal density were significantly increased.Peanut growth was also inhibited.However,inoculation with the P9 strain significantly promoted the growth of peanut under drought stress as plant height,fresh weight,root length and root weight were significantly higher compared with the uninoculated drought stress group.In addition,in P9-inoculated plants,the water and chlorophyll contents were significantly higher and the activities of the antioxidant enzymes CAT and SOD were significantly increased(except during the six days of drought treatment).While the stomatal length,width,and aperture were improved,the levels of MDA and H2O2 were significantly decreased.NBT staining showed that inoculation with P9 reduced O^(2−) accumulation under stress.After re-watering,the physiological indexes of inoculated plants recovered more quickly and grew better.Conclusions:The results showed that T.tyrosinosolvens P9 enhanced drought resistance and improves peanut growth by increasing leaf water content,increasing photosynthesis,regulating stomatal closure,and improving antioxidant enzyme activity.展开更多
Augmented Reality(AR)tries to seamlessly integrate virtual content into the real world of the user.Ideally,the virtual content would behave exactly like real objects.This necessitates a correct and precise estimation ...Augmented Reality(AR)tries to seamlessly integrate virtual content into the real world of the user.Ideally,the virtual content would behave exactly like real objects.This necessitates a correct and precise estimation of the user’s viewpoint(or that of a camera)with regard to the virtual content’s coordinate sys-tem.Therefore,the real-time establishment of 3-dimension(3D)maps in real scenes is particularly important for augmented reality technology.So in this paper,we integrate Simultaneous Localization and Mapping(SLAM)technology into augmented reality.Our research is to implement an augmented reality system without markers using the ORB-SLAM2 framework algorithm.In this paper we propose an improved method for Oriented FAST and Rotated BRIEF(ORB)feature extraction and optimized key frame selection,as well as the use of the Progressive Sample Consensus(PROSAC)algorithm for planar estimation of augmented reality implementations,thus solving the problem of increased sys-tem runtime because of the loss of large amounts of texture information in images.In this paper,we get better results by comparing experiments and data analysis.However,there are some improved methods of PROSAC algorithm which are more suitable for the detection of plane feature points.展开更多
基金supported by scientific research project of the Health Commission of Shanxi Province[NO.2018104]Science and Technology Innovation Project of Shanxi Province[NO.2020L0217 and 2022L172]+1 种基金Key Research and Development Projects of Shanxi Province[NO.A2021-113]Chinese Stomatological Association Dental Doctors Caries Prevention Ability Improvement Project[NO.CSA-ICP2022-05].
文摘Objective This study aimed to explore the spatial heterogeneity and risk factors for dental caries in 12-year-old children in Shanxi province,China.Methods The data encompassed 3,721 participants from the two most recent oral health surveys conducted across 16 districts in Shanxi Province in 2015 and 2018.Eighteen specific variables were analyzed to examine the interplay between socioeconomic factors,medical resources and environmental conditions.The Geo-detector model was employed to assess the impacts and interactions of these ecological factors.Results Socioeconomic factors(Q=0.30,P<0.05)exhibited a more substantial impact compared to environmental(Q=0.19,P<0.05)and medical resource factors(Q=0.25,P<0.05).Notably,the urban population percentage(UPP)demonstrated the most significant explanatory power for the spatial heterogeneity in caries prevalence,as denoted by its highest q-value(q=0.51,P<0.05).Additionally,the spatial distribution’s heterogeneity of caries was significantly affected by SO2 concentration(q=0.39,P<0.05)and water fluoride levels(q=0.27,P<0.05)among environmental factors.Conclusion The prevalence of caries exhibited spatial heterogeneity,escalating from North to South in Shanxi Province,China,influenced by socioeconomic factors,medical resources,and environmental conditions to varying extents.
基金supported by the National Natural Science Foundation of China(Grant Nos.:81973377,81903689,82073906 and 82273987)the Key Natural Science Foundation of Jiangsu Higher Education Institutions of China(Grant Nos.:19KJB350006 and 19KJA460008)+1 种基金Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),the initializing Fund of Xuzhou Medical University(Grant No.:D2018011)Postgraduate Research Practice Innovation Program of Jiangsu Province(Grant Nos.:KYCX21-2733 and KYCX22-2966).
文摘The occurrence of benign prostate hyperplasia(BPH)was related to disrupted sex steroid hormones,and metformin(Met)had a clinical response to sex steroid hormone-related gynaecological disease.However,whether Met exerts an antiproliferative effect on BPH via sex steroid hormones remains unclear.Here,our clinical study showed that along with prostatic epithelial cell(PEC)proliferation,sex steroid hormones were dysregulated in the serum and prostate of BPH patients.As the major contributor to dysregulated sex steroid hormones,elevated dihydrotestosterone(DHT)had a significant positive relationship with the clinical characteristics of BPH patients.Activation of adenosine 5'-monophosphate(AMP)-activated protein kinase(AMPK)by Met restored dysregulated sex steroid hormone homeostasis and exerted antiproliferative effects against DHT-induced proliferation by inhibiting the formation of androgen receptor(AR)-mediated Yes-associated protein(YAP1)-TEA domain transcription factor(TEAD4)heterodimers.Met’s anti-proliferative effects were blocked by AMPK inhibitor or YAP1 overexpression in DHT-cultured BPH-1 cells.Our findings indicated that Met would be a promising clinical therapeutic approach for BPH by inhibiting dysregulated steroid hormone-induced PEC proliferation.
基金This study is approved by the Institutional Ethics Committee of The Second Affiliated Hospital of Harbin Medical University(KY2021-049).
文摘Objective:This study aimed to estimate the incidence rate and clinical characteristics of inflammatory bowel disease(IBD)in the Chinese population,specially comparing the North and South regions.Methods:We designed a questionnaire survey for patients diagnosed with IBD and conducted a systematic literature search in PubMed,China National Knowledge Internet,and Wanfang digital database,covering studies published between 2012 and 2022.Meta-analysis was performed to determine the overall incidence rate and prevalence of clinical manifestations of Crohn's disease(CD)and ulcerative colitis(UC)in China's Mainland.Clinical phenotypes and demographic characteristics were calculated with 95%confidence intervals(CI).A comparison between the northern and southern regions was also conducted.Results:The questionnaire survey included 440 patients,and 64 publications were included for Meta-analysis.The overall incidence rates of IBD,CD,and UC were 1.36(95%CI:0.79-2.33)per 100,000 person-years,0.23(95%CI:0.09-0.58)per 100,000 person-years,and 1.12(95%CI:0.69-1.80)per 100,000 person-years,respectively.The incidence rates of IBD,CD,and UC were all higher in southern China compared to the North.Clinical characteristics of 440 IBD patients from the questionnaire and 2,821 CD patients and 12,809 UC patients from the literature were analyzed.There were more male patients compared to female patients.CD cases in the North exhibited earlier disease diagnosis(P<0.01),more upper gastrointestinal lesions(P<0.01),and higher hospitalizations rates(P<0.01)compared to the South.UC cases in the North had higher severity(P<0.01),anemia rates(P<0.01),and weight loss(P<0.01)compared to the South.Conclusions:The incidence rates of IBD,CD,and UC were higher in southern China than in the North.Northern patients exhibited more severe symptoms compared to their southern counterparts.
基金supported by the National Key R&D Program of China(2020YFA0406203)the Shenzhen Science and Technology Innovation Commission(JCYJ20180507181806316,JCYJ20200109105618137)+1 种基金the ECS Scheme(City U 21307019,City U7020043,City U7005500,City U7005612)the Shenzhen Research Institute,City University of Hong Kong。
文摘High-voltage LiCoO_(2)(LCO) is an attractive cathode for ultra-high energy density lithium-ion batteries(LIBs) in the 3 C markets.However,the sluggish lithium-ion diffusion at high voltage significantly hampers its rate capability.Herein,combining experiments with density functional theory(DFT) calculations,we demonstrate that the kinetic limitations can be mitigated by a facial Mg^(2+)+Gd^(3+)co-doping method.The as-prepared LCO shows significantly enhanced Li-ion diffusion mobility at high voltage,making more homogenous Li-ion de/intercalation at a high-rate charge/discharge process.The homogeneity enables the structural stability of LCO at a high-rate current density,inhibiting stress accumulation and irreversible phase transition.When used in combination with a Li metal anode,the doped LCO shows an extreme fast charging(XFC) capability,with a superior high capacity of 193.1 mAh g^(-1)even at the current density of 20 C and high-rate capacity retention of 91.3% after 100 cycles at 5 C.This work provides a new insight to prepare XFC high-voltage LCO cathode materials.
基金This work was supported by the Projects of International Cooperation and Exchanges NSFC(No.21761162015)the Foundation and Frontier Research Project of Chongqing of China(cstc2018jcyjAX0513)the Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN201801125).
文摘Bimetallic Pt-skin catalyst is a class of near-surface alloy(NSA)that owns a high degree of control over composition.Herein,density functional theory(DFT)is used to calculate the energetics of oxygen reduction reaction(ORR)on Pt-skin over Ir,Pd and Au substrates.A Brønsted-Evans-Polanyi(BEP)relationship can be determined for the oxygen molecule dissociation.The binding energy of both atomic oxygen and hydroxyl radical is found to correlate well with the d band center of Pt-skin atoms.Their catalytic activities show the volcano relationship as the positions of each substrate in the periodic table.The effect of surface strain,band structure and charge transfer on the d band center is well studied,and it can be found that the surface strain effect plays a dominant role for all Pt-skin catalysts.Ir substrate makes the d band center of Pt-skin go far away from the Fermi level,while Au substrate makes it move towards the Fermi level.Being different from both Ir and Au,Pd substrate makes the d band center of Pt-skin comparable with the monometallic Pt.
基金support from National Natural Science Foundation of China(No.21772188,No.22179109)Chongqing Natural Science Foundation(cstc2021ycjh-bgzxm0164,cstc2020jcyj-zdxmX0010)。
文摘Sulfur and selenium have been paid more and more attention in energy storage systems because of their high theoretical specific gravimetric and volumetric capacities.With the increasing scarcity of lithium resources,secondary batteries made of sulfur and selenium coupled with other alkali metal/alkaline earth metals(e.g.Na,K,Mg)are expected to play a vital role in future production and human life.Due to the volume expansion,poor conductivity and shuttle effect,the structure design of cathode,as one of the important roles in metal-S/Se batteries,has always been a hot and difficult point.In the review,various host materials of S and Se are clarified and discussed.Typically,carbonaceous materials are the most widely used hosts,while polar materials are becoming more and more popular in metal-S/Se batteries.Through a comprehensive overview,it is hoped that previous research experiences can provide further reference and guidance for the sustainable development of metal-S/Se batteries.
文摘锌-空气电池(ZAB)因其能量密度高、环境友好、成本低以及安全性高而备受关注.然而,空气电极上的氧还原反应(ORR)动力学缓慢,严重限制了ZAB的输出功率.尽管铂基催化剂展现出优异的ORR催化活性,但高昂的成本制约其大规模商业化应用.因此,迫切需要开发高效、低成本的ORR电催化剂.研究表明,具有原子分散Co-N4活性位点的Co-N-C单原子催化剂是理想的ORR非贵金属催化剂,但其仍然存在与反应关键中间体结合能较高的难题.目前的研究主要通过调控单原子配位环境与增大活性位点密度来提高Co-N-C催化剂的活性,但如何精确控制中心金属电子结构以及避免高温下金属原子的团聚仍面临巨大挑战.除了单原子活性位点外,催化剂载体的键合结构、电荷分布状态亦会影响载体本身和单原子位点的催化活性.然而,现有的研究主要聚焦于单原子位点或无金属催化剂单方面活性的提升,关于它们之间的相互作用对于催化性能影响的研究相对很少.为了进一步提高Co单原子催化剂的催化活性,本文通过简单的模板法与NH3二次处理策略制备了氮掺杂缺陷碳负载的Co-N_(5)位点单原子催化剂.电感耦合等离子体发射光谱结果表明,单原子Co的金属负载量高达2.57 wt%.此外,相比于未经过NH3二次处理的Co-Nx/HC样品,Co-N_(5)/DHC样品在电子顺磁共振谱中g=2.003处呈现出更明显的共振信号,在C 1s高分辨谱中具有更低的C-C(sp2杂化)/C-N(sp3杂化)比例以及明显增加的吡啶氮信号,证实了Co-N_(5)/DHC显著提升的氮掺杂碳缺陷浓度并具有丰富的边界/缺陷位点.同时,X射线吸收谱与球差矫正透射电子显微镜结果表明所制备的样品为原子分散的Co-N_(5)结构,从而证明成功制备了缺陷氮掺杂碳耦合Co-N_(5)位点单原子催化剂.电化学测试结果表明,缺陷氮掺杂碳耦合Co-N_(5)位点后表现较好的ORR性能,半波电位达到0.877 V,明显高于Co-Nx/HC对比样品和商业化Pt/C催化剂.Koutecky-Levich曲线和旋转盘环电极测试结果表明,Co-N_(5)/DHC催化剂的高效4e-反应路径.且在10000次的加速老化测试中,Co-N_(5)/DHC半波电位仅降低了7 m V,稳定性优于Pt/C.以Co-N_(5)/DHC为阴极催化剂组装的ZAB开路电压为1.45 V,峰值输出功率密度能够达到160.7 m W cm^(-2),并能提供766.2 m A h gZn-1的比容量,展现出较高的应用前景.密度泛函理论计算表明,Co-N_(5)位点与缺陷氮掺杂碳的相互作用诱导Co中心位点电子的重新分布,降低了ORR反应能垒.综上,本文为设计与合成高性能的Co单原子催化剂,用于先进的可再生能源转换系统提供了一种新思路.
基金financially supported by the National Natural Science Foundation of China(22279112,52022088,51971245,51772262,21406191,U20A20336,21935009)the Natural Science Foundation of Hebei Province,China(B2022203018,F2021203097,B2020203037,B2018203297)+2 种基金the Hunan Innovation Team,China(2018RS3091)the Beijing Natural Science Foundation,China(2202046)the Fok Ying-Tong Education Foundation of China(171064)。
文摘Understanding alkali metal ions’(e.g.,Li^(+)/Na^(+)/K^(+))transport mechanism is challenging but critical to improving the performance of alkali metal batteries.Herein using a-MnO_(2)nanowires as cathodes,the transport kinetics of Li^(+)/Na^(+)/K^(+)in the 2×2 channels of a-MnO_(2)with a growth direction of[001]is revealed.We show that ion radius plays a decisive role in determining the ion transport and electrochemistry.Regardless of the ion radii,Li^(+)/Na^(+)/K^(+)can all go through the 2×2 channels of a-MnO_(2),generating large stress and causing channel merging or opening.However,smaller ions such as Li^(+)and Na^(+)cannot only transport along the[001]direction but also migrate along the<110>direction to the nanowire surface;for large ion such as K^(+),diffusion along the<110>direction is prohibited.The different ion transport behavior has grand consequences in the electrochemistry of metal oxygen batteries(MOBs).For Li-O_(2)battery,Li^(+)transports uniformly to the nanowire surface,forming a uniform layer of oxide;Na^(+)also transports to the nanowire surface but may be clogged locally due to its larger radius,therefore sporadic pearl-like oxides form on the nanowire surface;K^(+)cannot transport to the nanowire surface due to its large radius,instead,it breaks the nanowire locally,causing local deposition of potassium oxides.The study provides atomic scale understanding of the alkali metal ion transport mechanism which may be harnessed to improve the performance of MOBs.
基金Supported by the Original Innovation Project(No.ZDBS-LY-DQC009)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB42000000)the National Key R&D Program of China(No.2019YFD0901103)。
文摘The geochemical characteristics and potential controlling factors of colloidal Zn,Cd,and Pb in Huanghe(Yellow)River estuary(HRE),China were investigated.The three metals were highly variable over a range of spatiotemporal scales,comprehensively forced by various physical and biological processes.Total dissolved Zn,Cd,and Pb varied from 200.1 to 321.7,2.6 to 4.1,and 0.5 to 1.0 nmol/L,respectively.Only one near-estuarine station of Zn had contamination factor values>1,which indicate the lower contaminant levels.Five dissolved species of Zn,Cd and Pb were fractionated,namely<1 kDa,1-3 kDa,3-10 kDa,10-100 kDa,and 100 kDa-0.45μm.The<1 kDa truly dissolved phase was the main fraction of the three dissolved metals(50%-62%),while the 100-kDa-0.45-μm high molecular weight colloidal fraction was dominant in their respective colloidal phase.Territorial input and sediment acted as important sources of strong ligands and natural colloids for the HRE water system.<3-kDa Zn and Pb were susceptible to the dissolved oxygen,the behaviors of colloidal Zn and 3-10-kDa Pb were related to dissolved organic carbon(DOC).However,no significant correlation between each dissolved fraction of Cd and salinity,pH,temperature,colloidal organic carbon,and DOC was found in this study.Overall,these findings,completed by the evaluation of the dissolved species of Zn,Cd,and Pb at 10 sites over the river-sea mixing zone,provided new insights into the colloidal heterogeneity that affect metals geochemical features,migration and fate in estuaries.
基金supported by the Jiangsu Provincial Key Research and Development Program (Grant No.BE2020616)the National Key R&D Program of China (Grant No.2018YFC1200603)+1 种基金the National Science and Technology Major Project (Grant No.2019SWAQ05-5-4)Jiangsu Key Lab of Cancer Biomarkers,Prevention and Treatment,Collaborative Innovation Center for Cancer Personalized Medicine,Nanjing Medical University.
文摘Although vaccines have been developed,mutations of SARS-CoV-2,especially the dominant B.1.617.2(delta)and B.1.529(omicron)strains with more than 30 mutations on their spike protein,have caused a significant decline in prophylaxis,calling for the need for drug improvement.Antibodies are drugs preferentially used in infectious diseases and are easy to get from immunized organisms.The current study combined molecular modeling and single memory B cell sequencing to assess candidate sequences before experiments,providing a strategy for the fabrication of SARS-CoV-2 neutralizing antibodies.A total of 128 sequences were obtained after sequencing 196 memory B cells,and 42 sequences were left after merging extremely similar ones and discarding incomplete ones,followed by homology modeling of the antibody variable region.Thirteen candidate sequences were expressed,of which three were tested positive for receptor binding domain recognition but only one was confirmed as having broad neutralization against several SARS-CoV-2 variants.The current study successfully obtained a SARS-CoV-2 antibody with broad neutralizing abilities and provided a strategy for antibody development in emerging infectious diseases using single memory B cell BCR sequencing and computer assistance in antibody fabrication.
基金the National Natural Science Foundation of China under Grant 31760030 and 32060028the Science and Technology Planning Project of Guizhou Province under Grant[2022]009.
文摘Background:The plant-growth-promoting rhizobacterium Tsukamurella tyrosinosolvens is a rare strain of actinomycete,in order to recognize and expand the ecological functions of rare actinomycetes.Methods:In this experiment,we studied the effect of Tsukamurella tyrosinosolvens P9 on the drought resistance of peanut by inoculating peanut seedlings in pots and measuring the growth and physiological indicators of peanut under drought stress and re-watering conditions.Results:The results showed that during drought stress,the relative water content of the soil and leaves,chlorophyll content,and stomatal length,width,and aperture were significantly decreased while the levels of malondialdehyde(MDA),H_(2)O_(2) and stomatal density were significantly increased.Peanut growth was also inhibited.However,inoculation with the P9 strain significantly promoted the growth of peanut under drought stress as plant height,fresh weight,root length and root weight were significantly higher compared with the uninoculated drought stress group.In addition,in P9-inoculated plants,the water and chlorophyll contents were significantly higher and the activities of the antioxidant enzymes CAT and SOD were significantly increased(except during the six days of drought treatment).While the stomatal length,width,and aperture were improved,the levels of MDA and H2O2 were significantly decreased.NBT staining showed that inoculation with P9 reduced O^(2−) accumulation under stress.After re-watering,the physiological indexes of inoculated plants recovered more quickly and grew better.Conclusions:The results showed that T.tyrosinosolvens P9 enhanced drought resistance and improves peanut growth by increasing leaf water content,increasing photosynthesis,regulating stomatal closure,and improving antioxidant enzyme activity.
基金supported by the Hainan Provincial Natural Science Foundation of China(project number:621QN269)the Sanya Science and Information Bureau Foundation(project number:2021GXYL251).
文摘Augmented Reality(AR)tries to seamlessly integrate virtual content into the real world of the user.Ideally,the virtual content would behave exactly like real objects.This necessitates a correct and precise estimation of the user’s viewpoint(or that of a camera)with regard to the virtual content’s coordinate sys-tem.Therefore,the real-time establishment of 3-dimension(3D)maps in real scenes is particularly important for augmented reality technology.So in this paper,we integrate Simultaneous Localization and Mapping(SLAM)technology into augmented reality.Our research is to implement an augmented reality system without markers using the ORB-SLAM2 framework algorithm.In this paper we propose an improved method for Oriented FAST and Rotated BRIEF(ORB)feature extraction and optimized key frame selection,as well as the use of the Progressive Sample Consensus(PROSAC)algorithm for planar estimation of augmented reality implementations,thus solving the problem of increased sys-tem runtime because of the loss of large amounts of texture information in images.In this paper,we get better results by comparing experiments and data analysis.However,there are some improved methods of PROSAC algorithm which are more suitable for the detection of plane feature points.
