Recently,developing carbon-based hybrid materials loaded with magnetic components has been generally regarded as a promising and practically feasible strategy when it comes to constructing lightweight electromagnetic ...Recently,developing carbon-based hybrid materials loaded with magnetic components has been generally regarded as a promising and practically feasible strategy when it comes to constructing lightweight electromagnetic wave absorbers.In the current work,reclaimed carbon black(CB)nanopowder was firstly produced by simple burning of wheat straw,which was then employed as sustainable carbon-based host materials(carrier)and successfully decorated Co@C nanoparticles via a simple thermal reduction process.Remarkably,both the as-fabricated nanocomposites and corresponding electromagnetic wave absorption performances could be effectively tuned by tailoring the dosage of the Co@C nanoparticles.The minimum reflection loss(RLmin)of–53.989 d B was achieved for CB/Co@C-2#at 2.28 mm thickness,meanwhile,CB/Co@C-3#was featured by a wide effective absorption band(EAB)of 6 GHz(6.72–12.72 GHz)at a 2.73 mm matching thickness,which covered the entire X band,suggesting that the CB/Co@C nanocomposites were an attractive candidate for electromagnetic wave absorber.According to the synergistic influence of dielectric loss and magnetic loss from CB and Co@C,respectively,as well as the properly matched impedance,a reasonable electromagnetic wave attenuation mechanism was illustrated.It is noteworthy that the preparation process of CB is a facile,recycled,and low-cost strategy for achieving nanoscale carbon-based absorbing materials,moreover,the CB/Co@C nanocomposites provide a reference for constructing lightweight dielectric-magnetic products with superb electromagnetic wave absorption performances.展开更多
为解决C语言数据类型在支持后下载应用的片上操作系统(COS)中无法完全满足应用程序数据的存储特性和安全需求的问题,分析了Java Card和C语言数据类型的属性,提出了一种基于 C 语言扩展的应用程序数据类型体系。根据数据分类,重点阐述了...为解决C语言数据类型在支持后下载应用的片上操作系统(COS)中无法完全满足应用程序数据的存储特性和安全需求的问题,分析了Java Card和C语言数据类型的属性,提出了一种基于 C 语言扩展的应用程序数据类型体系。根据数据分类,重点阐述了4种模块数据类型和5种应用数据类型。测试结果表明,该数据类型体系满足了COS应用程序数据的需求,有效提升了内存利用率和应用执行性能,为COS虚拟机运行时环境提供了高效的数据模型。展开更多
目的:评价A群C群脑膜炎球菌多糖结合疫苗(group A and group C meningococcal polysaccharide conjugate vaccine,MPCV-AC)和乙型肝炎疫苗(hepatitis B vaccine,HepB)同时接种后的安全性。方法:通过国家免疫规划信息系统和安徽省免疫规...目的:评价A群C群脑膜炎球菌多糖结合疫苗(group A and group C meningococcal polysaccharide conjugate vaccine,MPCV-AC)和乙型肝炎疫苗(hepatitis B vaccine,HepB)同时接种后的安全性。方法:通过国家免疫规划信息系统和安徽省免疫规划信息管理系统分别收集2020年至2022年安徽省适龄儿童MPCV-AC和HepB的疑似预防接种异常反应(adverse events following immunization,AEFI)数据和预防接种数据,比较2种疫苗同时接种和单独接种的AEFI的发生风险。结果:MPCV-AC第1剂次和HepB第3剂次同时接种、MPCV-AC第1剂次单独接种、HepB第3剂次单独接种的AEFI报告发生率分别为48.03/10万(280例)、56.37/10万(314例)、51.96/10万(283例);其中一般反应分别为43.91/10万(256例)、51.35/10万(286例)、48.65/10万(265例),异常反应分别为4.12/10万(24例)、4.85/10万(27例)、3.30/10万(18例)。同时接种组、单独接种组的AEFI发生风险、一般反应及异常反应的发生风险差异均无统计学意义。结论:MPCV-AC和HepB同时接种未增加AEFI的发生风险,可作为6月龄儿童同时接种MPCV-AC和HepB的科学依据。展开更多
Ni−Co−C alloy coatings with exceptional properties were fabricated via electrodeposition using an ammonium oxalate−ammonium citrate system.The optimized coatings exhibited dense crystallization with a distinct granula...Ni−Co−C alloy coatings with exceptional properties were fabricated via electrodeposition using an ammonium oxalate−ammonium citrate system.The optimized coatings exhibited dense crystallization with a distinct granular surface,where large particles were covered with nanoscale clusters.Additionally,C atoms primarily existed within the coatings as a solid solution,maintaining the FCC structures.Compared to binary Ni−Co coatings,the Ni−Co−C alloy coatings exhibited significantly improved hardness,wear resistance,and adhesion strength,which could be attributed to the potential strengthening effect of the C atoms.Specifically,the introduction of C atoms optimized the local charge density and electron distribution in the alloy,transforming local weak ionic bonds into strong covalent interactions,thereby enhancing the bonding capability between the corresponding atoms in the NiCo bulk.展开更多
The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these c...The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these catalysts were buried in the carbon matrix,resulting in a low metal utilization and inaccessibility for adsorption of reactants during the catalytic process.Herein,we reported a facile synthesis based on the hard-soft acid-base(HSAB)theory to fabricate Co single-atom catalysts with highly exposed metal atoms ligated to the external pyridinic-N sites of a nitrogen-doped carbon support.Benefiting from the highly accessible Co active sites,the prepared Co−N−C SAC exhibited a superior oxygen reduction reactivity comparable to that of the commercial Pt/C catalyst,showing a high turnover frequency(TOF)of 0.93 e^(−)·s^(-1)·site^(-1)at 0.85 V vs.RHE,far exceeding those of some representative SACs with a ultra-high metal content.This work provides a rational strategy to design and prepare M−N−C single-atom catalysts featured with high site-accessibility and site-density.展开更多
目的发现HIV/HCV合并感染者中HCV自发清除特点,找出HCV自发清除的影响因素及HCV自发清除者与HCV-RNA阳性患者之间的差异,为HIV/HCV合并感染者HCV-RNA筛查及治疗提供临床指导。方法以2022年1月—2024年5月云南省传染病医院符合纳入标准的...目的发现HIV/HCV合并感染者中HCV自发清除特点,找出HCV自发清除的影响因素及HCV自发清除者与HCV-RNA阳性患者之间的差异,为HIV/HCV合并感染者HCV-RNA筛查及治疗提供临床指导。方法以2022年1月—2024年5月云南省传染病医院符合纳入标准的HIV/HCV合并感染者作为研究对象,其中未治疗的HCV-RNA阴性者作为实验组(清除组)、未治疗的HCV-RNA阳性者作为对照组(阳性组),收集2组患者的人口统计学、临床特征、治疗和实验室检测指标,计算HCV自发清除的能力,采用logistic回归分析探讨HIV与HCV合并感染后HCV自发清除的影响因素,并比较清除组和阳性组实验室指标及其肝功能损伤情况。结果共收集到148例HIV/HCV合并感染者,其中清除组70例、阳性组78例(剔除资料不全者3例),HCV自发清除率为9.1%(70/773)。单因素分析结果表明年龄、抗反转录病毒治疗(antiretroviral therapy,ART)方案、抗病毒治疗时间≥16年均有统计学意义(P<0.05)。多因素回归分析表明使用含蛋白酶抑制剂方案(OR=0.228,95%CI:0.064~0.810)是阻碍HCV自发清除的影响因素,抗病毒治疗时间≥16年(OR=8.587,95%CI:1.854~39.775)是促进HCV自发清除的影响因素。比较阳性组和清除组实验室指标发现阳性组ALT、AST、天冬氨酸氨基转移酶与血小板比率指数(aspartate aminotransferase to platelet ratio index,APRI)评分、纤维化指数(fibrosis 4 score,FIB-4指数)平均值及异常率均高于HCV自发清除组(P<0.001)。结论HCV合并感染HIV患者的HCV自发清除率降低,使用含蛋白酶抑制剂的ART方案、抗病毒治疗时间≥16年是HCV自发清除的独立影响因素,HCV自发清除者较HCV阳性者的肝功能损伤程度更轻。展开更多
The weak adsorption energy of oxygen-containing intermediates on Co center leads to a considerable performance dis-parity between Co-N-C and costly Pt benchmark in catalyzing oxygen reduction reaction(ORR).In this wor...The weak adsorption energy of oxygen-containing intermediates on Co center leads to a considerable performance dis-parity between Co-N-C and costly Pt benchmark in catalyzing oxygen reduction reaction(ORR).In this work,we strategi-cally engineer the active site structure of Co-N-C via B substitution,which is accomplished by the pyrolysis of ammonium borate.During this process,the in-situ generated NH_(3)gas plays a critical role in creating surface defects and boron atoms substituting nitrogen atoms in the carbon structure.The well-designed CoB_(1)N_(3)active site endows Co with higher charge density and stronger adsorption energy toward oxygen species,potentially accelerating ORR kinetics.As expected,the resulting Co-B/N-C catalyst exhibited superior ORR performance over Co-N-C counterpart,with 40 mV,and fivefold en-hancement in half-wave potential and turnover frequency(TOF).More importantly,the excellent ORR performance could be translated into membrane electrode assembly(MEA)in a fuel cell test,delivering an impressive peak power density of 824 mW·cm^(-2),which is currently the best among Co-based catalysts under the same conditions.This work not only demon-strates an effective method for designing advanced catalysts,but also affords a highly promising non-precious metal ORR electrocatalyst for fuel cell applications.展开更多
基金the National Natural Science Foundation of China(Nos.51672144,51572137,51702181,52072196,52002199,52002200)the Major Basic Research Program of Natural Science Foundation of Shandong Province under Grant No.ZR2020ZD09+5 种基金the Shandong Provincial Key Research and Development Program(SPKR&DP)under Grant No.2019GGX102055the Natural Science Foundation of Shandong Province(Nos.ZR2019BEM042,ZR2020QE063)the Innovation and Technology Program of Shandong Province under Grant No.2020KJA004Guangdong Basic and Applied Basic Research Foundation(No.2019A1515110933)the China Postdoctoral Science Foundation(No.2020M683450)the Taishan Scholars Program of Shandong Province under No.ts201511034。
文摘Recently,developing carbon-based hybrid materials loaded with magnetic components has been generally regarded as a promising and practically feasible strategy when it comes to constructing lightweight electromagnetic wave absorbers.In the current work,reclaimed carbon black(CB)nanopowder was firstly produced by simple burning of wheat straw,which was then employed as sustainable carbon-based host materials(carrier)and successfully decorated Co@C nanoparticles via a simple thermal reduction process.Remarkably,both the as-fabricated nanocomposites and corresponding electromagnetic wave absorption performances could be effectively tuned by tailoring the dosage of the Co@C nanoparticles.The minimum reflection loss(RLmin)of–53.989 d B was achieved for CB/Co@C-2#at 2.28 mm thickness,meanwhile,CB/Co@C-3#was featured by a wide effective absorption band(EAB)of 6 GHz(6.72–12.72 GHz)at a 2.73 mm matching thickness,which covered the entire X band,suggesting that the CB/Co@C nanocomposites were an attractive candidate for electromagnetic wave absorber.According to the synergistic influence of dielectric loss and magnetic loss from CB and Co@C,respectively,as well as the properly matched impedance,a reasonable electromagnetic wave attenuation mechanism was illustrated.It is noteworthy that the preparation process of CB is a facile,recycled,and low-cost strategy for achieving nanoscale carbon-based absorbing materials,moreover,the CB/Co@C nanocomposites provide a reference for constructing lightweight dielectric-magnetic products with superb electromagnetic wave absorption performances.
文摘为解决C语言数据类型在支持后下载应用的片上操作系统(COS)中无法完全满足应用程序数据的存储特性和安全需求的问题,分析了Java Card和C语言数据类型的属性,提出了一种基于 C 语言扩展的应用程序数据类型体系。根据数据分类,重点阐述了4种模块数据类型和5种应用数据类型。测试结果表明,该数据类型体系满足了COS应用程序数据的需求,有效提升了内存利用率和应用执行性能,为COS虚拟机运行时环境提供了高效的数据模型。
文摘目的:评价A群C群脑膜炎球菌多糖结合疫苗(group A and group C meningococcal polysaccharide conjugate vaccine,MPCV-AC)和乙型肝炎疫苗(hepatitis B vaccine,HepB)同时接种后的安全性。方法:通过国家免疫规划信息系统和安徽省免疫规划信息管理系统分别收集2020年至2022年安徽省适龄儿童MPCV-AC和HepB的疑似预防接种异常反应(adverse events following immunization,AEFI)数据和预防接种数据,比较2种疫苗同时接种和单独接种的AEFI的发生风险。结果:MPCV-AC第1剂次和HepB第3剂次同时接种、MPCV-AC第1剂次单独接种、HepB第3剂次单独接种的AEFI报告发生率分别为48.03/10万(280例)、56.37/10万(314例)、51.96/10万(283例);其中一般反应分别为43.91/10万(256例)、51.35/10万(286例)、48.65/10万(265例),异常反应分别为4.12/10万(24例)、4.85/10万(27例)、3.30/10万(18例)。同时接种组、单独接种组的AEFI发生风险、一般反应及异常反应的发生风险差异均无统计学意义。结论:MPCV-AC和HepB同时接种未增加AEFI的发生风险,可作为6月龄儿童同时接种MPCV-AC和HepB的科学依据。
基金supported by the National Natural Science Foundation of China(Nos.52274320,52074053)。
文摘Ni−Co−C alloy coatings with exceptional properties were fabricated via electrodeposition using an ammonium oxalate−ammonium citrate system.The optimized coatings exhibited dense crystallization with a distinct granular surface,where large particles were covered with nanoscale clusters.Additionally,C atoms primarily existed within the coatings as a solid solution,maintaining the FCC structures.Compared to binary Ni−Co coatings,the Ni−Co−C alloy coatings exhibited significantly improved hardness,wear resistance,and adhesion strength,which could be attributed to the potential strengthening effect of the C atoms.Specifically,the introduction of C atoms optimized the local charge density and electron distribution in the alloy,transforming local weak ionic bonds into strong covalent interactions,thereby enhancing the bonding capability between the corresponding atoms in the NiCo bulk.
基金supported by Shanxi Province Science Foundation for Youths(202203021212300)Taiyuan University of Science and Technology Scientific Research Initial Funding(20212064)Outstanding Doctoral Award Fund in Shanxi Province(20222060).
文摘The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these catalysts were buried in the carbon matrix,resulting in a low metal utilization and inaccessibility for adsorption of reactants during the catalytic process.Herein,we reported a facile synthesis based on the hard-soft acid-base(HSAB)theory to fabricate Co single-atom catalysts with highly exposed metal atoms ligated to the external pyridinic-N sites of a nitrogen-doped carbon support.Benefiting from the highly accessible Co active sites,the prepared Co−N−C SAC exhibited a superior oxygen reduction reactivity comparable to that of the commercial Pt/C catalyst,showing a high turnover frequency(TOF)of 0.93 e^(−)·s^(-1)·site^(-1)at 0.85 V vs.RHE,far exceeding those of some representative SACs with a ultra-high metal content.This work provides a rational strategy to design and prepare M−N−C single-atom catalysts featured with high site-accessibility and site-density.
文摘目的发现HIV/HCV合并感染者中HCV自发清除特点,找出HCV自发清除的影响因素及HCV自发清除者与HCV-RNA阳性患者之间的差异,为HIV/HCV合并感染者HCV-RNA筛查及治疗提供临床指导。方法以2022年1月—2024年5月云南省传染病医院符合纳入标准的HIV/HCV合并感染者作为研究对象,其中未治疗的HCV-RNA阴性者作为实验组(清除组)、未治疗的HCV-RNA阳性者作为对照组(阳性组),收集2组患者的人口统计学、临床特征、治疗和实验室检测指标,计算HCV自发清除的能力,采用logistic回归分析探讨HIV与HCV合并感染后HCV自发清除的影响因素,并比较清除组和阳性组实验室指标及其肝功能损伤情况。结果共收集到148例HIV/HCV合并感染者,其中清除组70例、阳性组78例(剔除资料不全者3例),HCV自发清除率为9.1%(70/773)。单因素分析结果表明年龄、抗反转录病毒治疗(antiretroviral therapy,ART)方案、抗病毒治疗时间≥16年均有统计学意义(P<0.05)。多因素回归分析表明使用含蛋白酶抑制剂方案(OR=0.228,95%CI:0.064~0.810)是阻碍HCV自发清除的影响因素,抗病毒治疗时间≥16年(OR=8.587,95%CI:1.854~39.775)是促进HCV自发清除的影响因素。比较阳性组和清除组实验室指标发现阳性组ALT、AST、天冬氨酸氨基转移酶与血小板比率指数(aspartate aminotransferase to platelet ratio index,APRI)评分、纤维化指数(fibrosis 4 score,FIB-4指数)平均值及异常率均高于HCV自发清除组(P<0.001)。结论HCV合并感染HIV患者的HCV自发清除率降低,使用含蛋白酶抑制剂的ART方案、抗病毒治疗时间≥16年是HCV自发清除的独立影响因素,HCV自发清除者较HCV阳性者的肝功能损伤程度更轻。
基金the National Key Research and Development Program of China(2022YFB4004100)National Natural Science Foundation of China(22272161,22179126)+1 种基金the Jilin Province Science and Technology Development Program(YDZJ202202CXJD011,20240101019JC)Jilin Province major science and technology project(222648GX0105103875)for financial supports.
文摘The weak adsorption energy of oxygen-containing intermediates on Co center leads to a considerable performance dis-parity between Co-N-C and costly Pt benchmark in catalyzing oxygen reduction reaction(ORR).In this work,we strategi-cally engineer the active site structure of Co-N-C via B substitution,which is accomplished by the pyrolysis of ammonium borate.During this process,the in-situ generated NH_(3)gas plays a critical role in creating surface defects and boron atoms substituting nitrogen atoms in the carbon structure.The well-designed CoB_(1)N_(3)active site endows Co with higher charge density and stronger adsorption energy toward oxygen species,potentially accelerating ORR kinetics.As expected,the resulting Co-B/N-C catalyst exhibited superior ORR performance over Co-N-C counterpart,with 40 mV,and fivefold en-hancement in half-wave potential and turnover frequency(TOF).More importantly,the excellent ORR performance could be translated into membrane electrode assembly(MEA)in a fuel cell test,delivering an impressive peak power density of 824 mW·cm^(-2),which is currently the best among Co-based catalysts under the same conditions.This work not only demon-strates an effective method for designing advanced catalysts,but also affords a highly promising non-precious metal ORR electrocatalyst for fuel cell applications.
