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一种基于去斜技术的低成本宽带数字阵列天线设计与实现

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微波学报 2024年第5期40卷 21-28页

作者：于大群郝张成孙磊杨磊王阳毛建军东南大学信息科学与工程学院南京210096 南京电子技术研究所南京210039

宽带相控阵雷达具有高距离分辨率和多目标、群目标、高速目标的探测能力。传统宽带相控阵采用了基于真延时的方法来补偿孔径渡越效应,往往带来成本的大幅增加。本文提出了一种基于去斜处理的宽带单元级数字阵列天线系统设计方案,利用线... 详细信息

宽带相控阵雷达具有高距离分辨率和多目标、群目标、高速目标的探测能力。传统宽带相控阵采用了基于真延时的方法来补偿孔径渡越效应,往往带来成本的大幅增加。本文提出了一种基于去斜处理的宽带单元级数字阵列天线系统设计方案,利用线性调频信号波形时域与频域平移等效性,在去斜后采用移频移相的方式进行了等效孔径渡越补偿。相比传统宽带数字阵列设计,该方法可降低对天线硬件的性能要求,从而大幅压缩了天线系统制造的成本。本文详细分析了去斜体制的信号处理过程和方法,研制了天线阵列原型样机,验证了收发通道补偿及宽带波束。实测结果显示,该天线样机实现了500 MHz带宽下的方位±60°、俯仰±40°电扫。实测结果表明了宽带波束性能的良好性,宽带波束指向准确,验证了本文提出的基于去斜技术的宽带数字阵列设计方案的正确性。该方法可广泛用于宽带数字阵列天线的低成本设计与宽带性能提升。

关键词：去斜处理数字阵列天线宽带相控阵天线低成本

Improved Mechanical Properties in AZ31 Magnesium Alloys Induced by Impurity Reduction

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Journal of Wuhan University of Technology(Materials Science) 2013年第6期28卷 1207-1211页

作者： CHEN Xianhua PAN Fusheng mao jianjun ZHANG Zengshu College of Materials Science and Engineering Chongqing University National Engineering Research Center for Magnesium Alloys Chongqing University

Mechanical properties and microstructures of AZ31 magnesium alloys containing different impurity levels but having the same alloying element content, were investigated at ambient temperature. These AZ31 alloys were produced by semi-continuous casting, wherein the content of impurity was varied systematically. Microstructure observation shows that finer grains are existent in the alloy with lower impurity level. Tensile testing reveals that a reduction of impurity content results in a noticeable increase of the strength and elongation in the alloys in the cast, homogenized and extruded states. As the impurity content decreases from 0.0462wt% to 0.0163wt%, the ultimate tensile strength is evidently enhanced by 62 MPa and the elongation is nearly doubled in the homogenized specimen. The observed property improvement was discussed in terms of the microstructure variation with impurity reduction.

关键词： AZ31 magnesium alloys impurity reduction mechanical properties grain refinement

Development of high-strength,low-cost wrought Mg–2.0 mass% Zn alloy with high Mn content

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Progress in Natural Science:Materials International 2016年第6期26卷 630-635页

作者： Fusheng.Pan jianjun mao Gen Zhang Aitao Tang Jia She College of Materials Science and Engineering Chongqing University National Engineering Research Center for Magnesium Alloys Chongqing University Chongqing Research Center for Advanced Materials Chongqing Academy of Science and Technology Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China

Mg–Zn–Mn-based alloys have received considerable attention because of their high creep resistance, strength,and good corrosion resistance. The alloying element Mn in Mg–Zn-based alloys is commonly less than 1 wt%. In the present study, the effect of high Mn content(1 wt% and 2 wt%) on the microstructures and mechanical properties of Mg–2Zn–0.3Sr extruded alloy was investigated. The results revealed that the high Mn content significantly increased the ultimate tensile strength, tensile yield strength, compress yield strength, and yield asymmetry of the alloy without affecting its ductility. The dynamically recrystallized(DRXed) grains of Mg–2Zn–0.3Sr were remarkably refined because of the large amount of fine Mn precipitates in the homogenized alloy. The improved strengths were mainly attributed to the fine DRXed grains according to the Hall–Petch effect and to the large amount of spherical and Mn precipitates through the precipitation and dispersion strengthening. The fine DRXed grains and numerous Mn precipitates effectively suppressed the extension twining, substantially enhanced the compress yield strength, and resulted in improved anisotropy.

关键词： Magnesium alloy Mg–Zn alloy Microstructure Ultra-fine grains Second phase Mechanical properties

FeCoCrNiAl高熵合金涂层的等离子熔覆工艺研究

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热加工工艺 2024年第4期53卷 46-50页

作者：毛建军许启民赵禹张成林滕常青辛虹阳吴璐中国核动力研究设计院第一研究所四川成都610041 安徽工程大学高性能有色金属材料安徽省重点实验室安徽芜湖241000 安徽拓宝增材制造科技有限公司安徽芜湖241200

采用等离子熔覆技术在45号钢基体表面制备FeCoCrNiAl高熵合金涂层,研究熔覆电流和离子气流量对涂层表面形貌及孔隙率的影响。结果表明,当熔覆电流为180 A、离子气流量为2.5 L/min、熔覆速度为100 cm/min时,制备出的FeCoCrNiAl合金涂层... 详细信息

采用等离子熔覆技术在45号钢基体表面制备FeCoCrNiAl高熵合金涂层,研究熔覆电流和离子气流量对涂层表面形貌及孔隙率的影响。结果表明,当熔覆电流为180 A、离子气流量为2.5 L/min、熔覆速度为100 cm/min时,制备出的FeCoCrNiAl合金涂层与基体结合良好、无裂纹,孔隙率达到最低值0.0276%。该工艺制备的FeCoCrNiAl合金涂层高熵效应显著,但组织中除了具有BCC结构相以外,还存在具有FCC结构的Fe-Cr相、Ni-Co相、富Ni相、富Al相等成分。FeCoCrNiAl高熵合金涂层的显微硬度为500 HV,达到45钢基体的2倍以上。

关键词：高熵合金等离子熔覆涂层孔隙率硬度

Stable isotope labelled mass spectrometry for quantification of the relative abundances for expressed proteins induced by PeaT1

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Science China(Life Sciences) 2010年第12期53卷 1410-1417页

作者： LI GuangYue YANG XiuFen ZENG HongMei mao jianjun LIU Hua ZHANG YunHua QIU DeWen Key Laboratory for Biological Control of the Ministry of Agriculture Institute of Plant ProtectionChinese Academy of Agricultural SciencesBeijing 100081China

The protein elicitor from the mycelium of Alternaria tenuissima has been *** elicitor triggered resistance to the tobacco mosaic virus in tobacco by inducing relative oxygen species,but without causing hypersensitive *** elicitor is reported to impart resistance against Verticillium dahliae and to increase yield in cotton,but its mechanism is not yet *** this study,the stable isotope labelled mass spectrometry method was used to quantify the relative abundances of protein expression induced by PeaT1 in Arabidopsis.A significant difference in the relative abundances for the expression of different proteins related to metabolism,modification,regulatory,defense,stress and antioxidation was found in Arabidopsis.

关键词： protein elicitor stable isotope labelling relative abundances PeaT1

Responses of arbuscular mycorrhizal fungi to straw return and nitrogen fertilizer reduction in a rainfed maize field

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Pedosphere 2024年第2期34卷 351-360页

作者： Zhenling PENG Hao XI Lin mao Huyuan FENG jianjun ZHANG Yongjun LIU State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems College of EcologyLanzhou UniversityLanzhou 730000China College of Life Sciences Northwest Normal UniversityLanzhou 730070China School of Life Sciences Lanzhou UniversityLanzhou 730000China Dryland Agriculture Institute Gansu Academy of Agricultural SciencesLanzhou 730070China

Straw return can be used to reduce fertilizer input and improve agricultural sustainability and soil ***,how straw return and reduced fertilizer application affect beneficial soil microbes,particularly arbuscular mycorrhizal fungi(AMF),remains poorly ***,we conducted a five-year field experiment in a rainfed maize field on the Loess Plateau of northwestern *** tested four treatments with straw return combined with four nitrogen(N)application rates,i.e.,100%,80%,60%,and 0%of the common N application rate(225 kg N ha^(-1)year^(-1))in this region,and two reference treatments(full or no N application),with three replicates for each *** colonization was quantified and AMF communities colonizing maize roots were characterized using Illumina *** virtual taxa(VTs)of AMF were identified in root samples,among which VT113(related to Rhizophagus fasciculatus)and VT156(related to Dominikia gansuensis)were the predominant *** root length colonization and AMF VT richness were sensitive to N fertilization,but not to straw return;furthermore,both gradually increased with decreasing N application *** VT composition of the AMF community was also affected by N fertilization,but not by straw return,and the community variation could be well explained by soil available N and phosphorus ***,60%,80%,and full N fertilization produced similar maize ***,our study revealed the response patterns of AMF to straw return and N fertilizer reduction and showed that straw return combined with N fertilizer reduction may be a promising practice to maintain mycorrhizal symbiosis concomitantly with crop productivity.

关键词： agricultural sustainability crop productivity mycorrhizal colonization mycorrhizal symbiosis root length colonization virtual taxon

A novel approach to melt purification of magnesium alloys

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Journal of Magnesium and Alloys 2016年第1期4卷 8-14页

作者： Fusheng Pan Xianhua Chen Tao Yan Tingting Liu jianjun mao Wei Luo Qin Wang Jian Peng Aitao Tang Bin Jiang College of Materials Science and Engineering Chongqing UniversityChongqing 400045China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400045China Chongqing Academy of Science and Technology Chongqing 401123China

A novel low-cost method for melt purification of magnesium alloys,the melt self-purifying technology(MSPT),has been developed successfully based on a low temperature melt treatment(LTMT)without adding any *** iron solubility in the molten liquid of magnesium and its alloys,and the settlement velocity of iron particles were *** is shown that the low temperature melt treatment is an effective method to decrease the impurity Fe content in magnesium and its *** any additions,the Fe content in the AZ31 alloy was reduced to 15 ppm from the initial 65 ppm,and the Fe content in the AZ61 melt was decreased to 20 ppm from the initial 150 ppm after the low temperature melt *** results also showed that the Fe content in AM60 and AM50 dropped to 15 and 18 ppm,respectively,from the initial 150 ppm after the low temperature melt *** ZK 60,the Fe content in the melt down to less than 5 ppm was *** the low temperature melt treatment,the Si content in the above alloys was also decreased obviously.

关键词： Magnesium alloys Purification Impurity Melt Iron Silicon

Effect of graphene nanoplatelets(GNPs)addition on strength and ductility of magnesium-titanium alloys

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Journal of Magnesium and Alloys 2013年第3期1卷 242-248页

作者： Muhammad Rashad Fusheng Pan Aitao Tang Yun Lu Muhammad Asif Shahid Hussain Jia She Jun Gou jianjun mao College of Material Sciences and Engineering Chongqing UniversityChongqing 400044China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China Chongqing Academy of Science and Technology Chongqing 401123China Graduate School&Faculty of Engineering Chiba UniversityChiba 263-8522Japan School of Material Sciences and Engineering Dalian University of TechnologyDalian 116024China

Effect of graphene nanoplatelets(GNPs)addition on mechanical properties of magnesium–10wt%Titanium(Mg–10Ti)alloy is investigated in current *** Mg-(10Ti+0.18GNPs)composite was synthesized using the semi powder metallurgy method followed by hot *** characterization results revealed the uniform distribution of reinforcement(Ti+GNPs)particles in the matrix,therefore(Ti+GNPs)particles act as an effective reinforcing filler to prevent the *** temperature tensile results showed that the addition of Ti+GNPs to monolithic Mg lead to increase in 0.2%yield strength(0.2%YS),ultimate tensile strength(UTS),and failure *** Electron Microscopy(SEM),Energy-Dispersive X-ray Spectroscopy(EDS)and X-Ray Diffraction(XRD)were used to investigate the surface morphology,elemental dispersion and phase analysis,respectively.

关键词： Magnesium Titanium Graphene nanoplatelets Alloy Composite materials Powder metallurgy Mechanical properties

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古籍数字化工作中的版本问题

图书馆杂志 2017年第1期36卷 77-79,96页

作者：毛建军兴义民族师范学院文传学院

古籍数字化的技术实现和持续的资源建设意味着古籍版本学研究范围的不断扩大。古籍书目数据库对古籍版本的信息研究将产生全新的范式和理念。古籍版本是古籍全文数据库成功的关键,古籍全文数据库建设必须采取合理的版本模式。古籍数字... 详细信息

古籍数字化的技术实现和持续的资源建设意味着古籍版本学研究范围的不断扩大。古籍书目数据库对古籍版本的信息研究将产生全新的范式和理念。古籍版本是古籍全文数据库成功的关键,古籍全文数据库建设必须采取合理的版本模式。古籍数字化资源为古籍的版本鉴定工作和方法提供了全新思路。

关键词：古籍数字化古籍版本版本鉴定