The easy-plane anisotropy of the Y_(2)Co_(17)rare earth soft magnetic alloy has high saturation magnetization and operating frequency,and good impedance matching.Therefore,it is expected to become a kind of high-perfo...The easy-plane anisotropy of the Y_(2)Co_(17)rare earth soft magnetic alloy has high saturation magnetization and operating frequency,and good impedance matching.Therefore,it is expected to become a kind of high-performance microwave absorbing material.In this paper,Y_(2)Co_(17)alloy was prepared by a reduction-diffusion method,and its micropowder was prepared as polyurethane(PU)based composite absorbing materials(Y_(2)Co_(17)/PU composites).The microwave properties of composites with different volume fractions were calculated.The composites showed outstanding absorption characteristics in the range of 20-30 vol%,and the minimum reflection loss(RL)was less than-50 d B.When the volume fraction was25%,the effective absorption bandwidth could cover the X-band at a thickness of 1.5 mm,and the Ku-band at a thickness of1.08 mm.The absorption mechanism was analyzed by the interface reflection model.The RL absorption peak bandwidth mechanism was discussed by using the amplitude relation and calculating the effective absorption bandwidth at different thicknesses.The effective absorption bandwidth values were in good agreement with the theoretical expectation.展开更多
针对预警探测情报保障系统组成结构复杂、系统规模日益庞大、集成装备种类多样以及越来越短的产品研制周期要求,对DoDAF(Department of Defense Architecture Framework)体系结构进行了研究,分析了DoDAF产品的内涵、相互关联关系及使用...针对预警探测情报保障系统组成结构复杂、系统规模日益庞大、集成装备种类多样以及越来越短的产品研制周期要求,对DoDAF(Department of Defense Architecture Framework)体系结构进行了研究,分析了DoDAF产品的内涵、相互关联关系及使用模式,提出一种基于DoDAF的预警探测情报保障体系结构建模方法,结合实例给出了体系结构产品的设计过程,并对DoDAF开放体系结构的优点、在实践中可能遇到的问题及解决方法进行了分析。展开更多
本文通过高温固相法制备BaCeO_3-CeO_2复合电解质。采用XRD、SEM和交流阻抗技术分析材料的物相、结构和电学性能。结果表明:BaCeO_3-CeO_2复合电解质由钙钛矿型Ba Ce O3和少量立方相Ce O2构成。随着Ce O2含量的增加,Ba Ce O3的晶粒变小,...本文通过高温固相法制备BaCeO_3-CeO_2复合电解质。采用XRD、SEM和交流阻抗技术分析材料的物相、结构和电学性能。结果表明:BaCeO_3-CeO_2复合电解质由钙钛矿型Ba Ce O3和少量立方相Ce O2构成。随着Ce O2含量的增加,Ba Ce O3的晶粒变小,Ce O2颗粒主要出现在晶界处。BaCeO_3-CeO_2复合电解质的总电导率遵守Arrhenius法则,随着温度从773 K到1073 K的逐渐升高而逐渐增加。当Ce O2的含量达到20%时,BaCeO_3-CeO_2复合电解质获得最大电导率。伴随着Ce O2含量在晶界处的增加,BaCeO_3-CeO_2复合电解质的电导率在4%H_2O-H2和空气中的电导率都明显提高。展开更多
Most resistance-type humidity sensors exhibit negative humidity sensitivity,i.e.,their resistance decreases with a corresponding increase in humidity.This is primarily attributed to the dominant role of ionic conducti...Most resistance-type humidity sensors exhibit negative humidity sensitivity,i.e.,their resistance decreases with a corresponding increase in humidity.This is primarily attributed to the dominant role of ionic conduction in adsorbed water.In this work,a humidity sensor based on a p-type reduced graphene oxide(p-rGO)with positive humidity sensitivity is proposed.Moreover,its positive humidity sensing response is further enhanced by n-type WS_(2) nanoparticles modification.The results show that both rGO and r GO/WS_(2) humidity sensors have good linear response in the relative humidity(RH)range of0%-91.5%.The sensitivity of the rGO/WS_(2) humidity sensor is 1.87 times that of rGO humidity sensor,which is mainly attributed to p-n heterojunction between rGO and WS_(2).Besides,the r GO/WS_(2) humidity sensor has small humidity hysteresis(-3%RH)and good repeatability.This work demonstrates a humidity sensor based on rGO/WS_(2) composite film and provides a facile route for fabricating humidity sensor with positive humidity sensing properties.展开更多
In this editorial we comment on the review by Wang et al published in the recent issue of the World Journal of Gastroenterology in 2023.Small extracellular vesicles(exosomes)play important roles in the tumor microenvi...In this editorial we comment on the review by Wang et al published in the recent issue of the World Journal of Gastroenterology in 2023.Small extracellular vesicles(exosomes)play important roles in the tumor microenvironment.In this review,the authors introduce the following points:(1)The composition and function of exosomal microRNAs(miRNAs)of different cell origins in hepatocellular carcinoma(HCC);(2)the crosstalk between exosomal miRNAs from stromal cells and immune cells in the tumor microenvironment and the progression of HCC;and(3)the potential applicability of exosomal miRNAs derived from mesenchymal stem cells in the treatment of HCC.In addition,the potential applicability of exosomal miRNAs derived from mesenchymal stem cells in the treatment of HCC was introduced.In this review,the authors give us an overview of the exosomal RNA and summarize the function of exosomal RNA in HCC,which provides a deeper understanding of exosomal miRNAs to the readers.展开更多
基金Project supported by the National Key R&D Program of China(Grant No.2021YFB3501302)the National Natural Science Foundation of China(Grant No.51731001)supported by the State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization’s key of research and development projects。
文摘The easy-plane anisotropy of the Y_(2)Co_(17)rare earth soft magnetic alloy has high saturation magnetization and operating frequency,and good impedance matching.Therefore,it is expected to become a kind of high-performance microwave absorbing material.In this paper,Y_(2)Co_(17)alloy was prepared by a reduction-diffusion method,and its micropowder was prepared as polyurethane(PU)based composite absorbing materials(Y_(2)Co_(17)/PU composites).The microwave properties of composites with different volume fractions were calculated.The composites showed outstanding absorption characteristics in the range of 20-30 vol%,and the minimum reflection loss(RL)was less than-50 d B.When the volume fraction was25%,the effective absorption bandwidth could cover the X-band at a thickness of 1.5 mm,and the Ku-band at a thickness of1.08 mm.The absorption mechanism was analyzed by the interface reflection model.The RL absorption peak bandwidth mechanism was discussed by using the amplitude relation and calculating the effective absorption bandwidth at different thicknesses.The effective absorption bandwidth values were in good agreement with the theoretical expectation.
文摘针对预警探测情报保障系统组成结构复杂、系统规模日益庞大、集成装备种类多样以及越来越短的产品研制周期要求,对DoDAF(Department of Defense Architecture Framework)体系结构进行了研究,分析了DoDAF产品的内涵、相互关联关系及使用模式,提出一种基于DoDAF的预警探测情报保障体系结构建模方法,结合实例给出了体系结构产品的设计过程,并对DoDAF开放体系结构的优点、在实践中可能遇到的问题及解决方法进行了分析。
基金the National Science Funds for Excellent Young Scholars of China(No.61822106)the National Science Funds for Creative Research Groups of China(No.61421002)the National Natural Science Foundation of China(No.61671115)。
文摘Most resistance-type humidity sensors exhibit negative humidity sensitivity,i.e.,their resistance decreases with a corresponding increase in humidity.This is primarily attributed to the dominant role of ionic conduction in adsorbed water.In this work,a humidity sensor based on a p-type reduced graphene oxide(p-rGO)with positive humidity sensitivity is proposed.Moreover,its positive humidity sensing response is further enhanced by n-type WS_(2) nanoparticles modification.The results show that both rGO and r GO/WS_(2) humidity sensors have good linear response in the relative humidity(RH)range of0%-91.5%.The sensitivity of the rGO/WS_(2) humidity sensor is 1.87 times that of rGO humidity sensor,which is mainly attributed to p-n heterojunction between rGO and WS_(2).Besides,the r GO/WS_(2) humidity sensor has small humidity hysteresis(-3%RH)and good repeatability.This work demonstrates a humidity sensor based on rGO/WS_(2) composite film and provides a facile route for fabricating humidity sensor with positive humidity sensing properties.
基金Supported by the National Natural Science Foundation of China,No.82303441Natural Science Foundation of Shanghai Municipality,No.21ZR1459100 and No.22ZR1457900+1 种基金Science and Technology Commission of Shanghai Municipality,No.20DZ2254500Shanghai Anticancer Association EYAS Project.
文摘In this editorial we comment on the review by Wang et al published in the recent issue of the World Journal of Gastroenterology in 2023.Small extracellular vesicles(exosomes)play important roles in the tumor microenvironment.In this review,the authors introduce the following points:(1)The composition and function of exosomal microRNAs(miRNAs)of different cell origins in hepatocellular carcinoma(HCC);(2)the crosstalk between exosomal miRNAs from stromal cells and immune cells in the tumor microenvironment and the progression of HCC;and(3)the potential applicability of exosomal miRNAs derived from mesenchymal stem cells in the treatment of HCC.In addition,the potential applicability of exosomal miRNAs derived from mesenchymal stem cells in the treatment of HCC was introduced.In this review,the authors give us an overview of the exosomal RNA and summarize the function of exosomal RNA in HCC,which provides a deeper understanding of exosomal miRNAs to the readers.
