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Journal of Materials Science & Technology 2010年第2期26卷 151-155页

作者： Zhenya zhang, huashun Yu , Shaoqing Wang, Haitao Wang and Guanghui Min Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061, China Key Laboratory of Liquid Structure and Heredity of Materials Ministry of Education Shandong University Jinan 250061 China

This study investigated the microstructures and mechanical properties of ZK60 alloy prepared by a simplified rapid solidification powder metallurgy （RS P/M） processing system （S-RS P/M）, which consists of warm press in dry air and hot extrusion. Microstructure characterizations showed that S-RS P/M alloy consisted of magnesium matrix and oxide stringers of ~1 #m in width. TEM （transmission electron microscopy） observations illustrated nano-size magnesia particles （10-30 nm） constituted oxide stringer in detail. Due to a relatively higher volume of nano-size magnesia particle produced during S-RS P/M process, 0.2% yield strength of S-RS P/M ZKO0 alloy was found to be as high as 382 MPa, which is 10% higher than that of RS P/M alloy. The improvement in mechanical properties is mainly attributed to the combination effects of Orowan mechanism and coefficient of thermal expansion （CTE） mismatch because of the approximately same average grain size.

关键词： Microstructure Mechanical properties Rapid solidification powder metallurgy Nano-size magnesia

Operation of the CSNS Penning surface H^- ion source

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Science China(Physics,Mechanics & Astronomy) 2011年第S2期54卷 245-248页

作者： WU XiaoBing OUYANG HuaFu CHI YunLong HE Wei HUANG Tao LI Gang LIU YingMan LU YanHua XU TaoGuang zhang JunSong zhang huashun ZHAO FuXiang Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Graduate University of Chinese Academy of Sciences Beijing 100049China

The accelerator complex of the China Spallation Neutron Source (CSNS) consists of a H- linear accelerator (linac) and a rapid cycling synchrotron (RCS). The linac contains a Penning surface H- ion source. The designed energy and the beam current of the source are 50 keV and 20 mA respectively, with a normalized root mean square (norm. rms.) emittance of 0.2π mm mrad. The manufactures and tests of the discharge chamber are in great progress. The construction of H- ion source test stand has been completed, and the operation of the source is also in progress. Stable H- ion beams with energy of 50 keV and current up to 50 mA are attained. Emittance measurement for the H- beam is being prepared.

关键词： CSNS Penning H- ion source discharge chamber current emittance

Operation of the CSNS Penning surface H- ion source

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Operation of the CSNS Penning surface H- ion source

Microstructural Evolution of Rapidly Solidified ZK60 Powders during Extrusion

第一届中国粒子加速器会议

作者： WU XiaoBing OUYANG HuaFul CHI YunLongl HE Wei HUANG Tao LI Gang LIU YingMan LU YanHua XU TaoGuang zhang JunSong zhang huashun ZHAO FuXiang Institute of High Energy Physics Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

The accelerator complex of the China Spallation Neutron Source(CSNS) consists of a H linear accelerator(linac) and a rapid cycling synchrotron(RCS).The linac contains a Penning surface H ion *** designed energy and the beam current of the source are 50 keV and 20 mA respectively,with a normalized root mean square(***.) emittance of 0.2πmm mrad. The manufactures and tests of the discharge chamber are in great *** construction of H ion source test stand has been completed,and the operation of the source is also in *** H ion beams with energy of 50 keV and current up to 50 mA are *** measurement for the H beam is being prepared.

关键词： CSNS Penning H- ion source discharge chamber current emittance

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Journal of Materials Science & Technology 2011年第2期27卷 159-164页

作者： Zhenya zhang huashun Yu Shaoqing Wang Hui Yu Guanghui Min Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationShandong UniversityJinan 250061China School of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013China

The microstructural evolution of rapidly solidified（RS） ZK60 powders extruded at 250 C was *** was shown that formation of new ultrafine grains took place through continuous dynamic recrystallization（CDRX）,accompanied by the perfect bonding of powders via severe plastic *** a low strain level,a well-defined structure made up of equiaxed and elongated subgrains was ***,the operation of basal and non-basal dislocation slip led to the formation of low-angle dislocation cells（LADC） within the elongated *** increasing strain,the number and average misorientation of LADC increased,resulting in fragmentation of original elongation subgrains into a finally homogeneous fine-grained *** full-recrystallized structure with an average grain size of 0.4 μm was finally evolved after large cumulative *** results suggested that structural change was connected with thermal strain,where dislocation activities dominated this process.

关键词： Microstructure Extrusion ZK60 powders Dislocation slip

Al-Si/Al_2O_3 in situ composite prepared by displacement reaction of CuO/Al system

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China Foundry 2010年第1期7卷 19-23页

作者： zhang Jing Yu huashun Chen Hongmei Min Guanghui Key Laboratory of Liquid Structure and Heredity of Materials Ministry of Education Shandong University Jinan Shandong China

Al2O3 particle-reinforced ZL109 composite was prepared by in situ reaction between CuO and Al2O3 . The microstructure was observed by means of OM, SEM and TEM. The Al2O3 particles in sub-micron sizes distribute uniformly in the matrix, and the Cu displaced from the in situ reaction forms net-like alloy phases with other alloy elements. The hardness and the tensile strength of the composites at room temperature have a slight increase as compared to that of the matrix. However, the tensile strength at 350℃ has reached 90.23 MPa, or 16.92 MPa higher than that of the matrix. The mechanism of the reaction in the CuO/AI system was studied by using of differential scanning calorimetry（DSC） and thermodynamic calculation. The reaction between CuO and Al involves two steps. First, CuO reacts with Al to form Cu20 and Al2O3 at the melting temperature of the matrix alloy, and second, Cu20 reacts with Al to form Cu and Al2O3 at a higher temperature. At ZL109 casting temperature of 750- 780 ℃, the second step can also take place because of the effect of exothermic reaction of the first step.

关键词： aluminium matrix composites in situ reaction Al2O3 particles ZL109 CuO

基于启动子和信号肽优化提高谷氨酰胺酶在枯草芽孢杆菌中的分泌表达

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微生物学通报 2024年第5期51卷 1536-1549页

作者：毛泽敬张祖政陈铭望松柏牛硕余华顺张彦郑贤良安琪酵母股份有限公司湖北宜昌443003 酵母功能湖北省重点实验室湖北宜昌443003 农业微生物挖掘与利用全国重点实验室湖北宜昌443003 三峡大学生物与制药学院湖北宜昌443002

【背景】谷氨酰胺酶(glutaminase)是一种能够催化L-谷氨酰胺水解生成L-谷氨酸和氨的酶,在食品、医药等领域有重要的应用价值。【目的】研究不同启动子和信号肽对谷氨酰胺酶分泌表达的影响、构建能高效分泌表达谷氨酰胺酶的枯草芽孢杆菌(... 详细信息

【背景】谷氨酰胺酶(glutaminase)是一种能够催化L-谷氨酰胺水解生成L-谷氨酸和氨的酶,在食品、医药等领域有重要的应用价值。【目的】研究不同启动子和信号肽对谷氨酰胺酶分泌表达的影响、构建能高效分泌表达谷氨酰胺酶的枯草芽孢杆菌(Bacillus subtilis)工程菌株,提高谷氨酰胺酶的产量。【方法】选用枯草芽孢杆菌SCK6作为表达宿主,构建带有不同启动子和信号肽的谷氨酰胺酶表达载体及重组菌株,分析不同基因元件对谷氨酰胺酶表达及分泌的影响,筛选最优启动子和信号肽,组合优化,构建高效分泌表达谷氨酰胺酶的工程菌株。【结果】实现了谷氨酰胺酶在枯草芽孢杆菌中的分泌表达,在以P_(HpaII)-P_(aprE)为启动子、YndA为信号肽的条件下,摇瓶发酵胞外最高酶活达到6.7U/mL。【结论】通过对启动子、信号肽关键基因元件进行筛选组合,构建了一株高效分泌表达谷氨酰胺酶的菌株,为酶的高效分泌表达提供了一种有效的方法。

关键词：枯草芽孢杆菌谷氨酰胺酶启动子信号肽分泌表达

Effect of CuO addition on microstructure and properties of aluminum composites produced by quick spontaneous infiltration process

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China Foundry 2014年第3期11卷 191-196页

作者： zhang Jingjing Lee Jung-Moo Cho Young-Hee Kim Su-Hyeon Yu huashun Key Laboratory of Liquid Structure and Heredity of Materials Ministry of Education Shandong University Light Metal Division Korea Institute of Materials Science

Al matrix composites with a high volume fraction of reinforcements were fabricated with a compact of Al-Ti-B4C powder mixtures by quick spontaneous infiltration(QSI) process in an aluminum melt. Given the exothermal nature of the reaction between CuO and Al, a certain amount of CuO addition to the Al-Ti-B4C system dramatically increases the adiabatic temperature and thereby enables the complete combustion reaction in an aluminum melt(about 1,173 K). After the QSI process, the compact fabricated with CuO retains its original shape and the obtained composite exhibits sound microstructure containing reaction products of TiB2, Al3BC and B4C. The formation of such reinforcements when adding CuO contributes to enhancing the properties of the composites that show far superior hardness and elastic modulus of 3.03 GPa and 158.9 GPa, respectively, with lower coefficient of thermal expansion(9.44 ppm?K-1) compared to those with no CuO addition.

关键词： Al composite CuO addition Al-Ti-B4C microstructure mechanical properties

湖南南山国家公园生态区资源冷杉种群现状调查

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湖北林业科技 2024年第2期53卷 41-45页

作者：刘美玲刘其武杨相伦陈鹏张荣华罗至柔肖化顺湖南南山国家公园管理局邵阳422500 中南林业科技大学长沙410004

掌握资源冷杉野生种群生长现状,是制定种群保育措施与开展生物多样性保护的重要依据。本研究采用样地和样方调查方法,对湖南南山国家公园生态区的资源冷杉野生种群进行详细调查,分析了现存资源冷杉种群的数量分布、生境特征、群落结构... 详细信息

掌握资源冷杉野生种群生长现状,是制定种群保育措施与开展生物多样性保护的重要依据。本研究采用样地和样方调查方法,对湖南南山国家公园生态区的资源冷杉野生种群进行详细调查,分析了现存资源冷杉种群的数量分布、生境特征、群落结构、年龄结构以及胸径树高结构等方面的现状。结果表明:湖南南山国家公园生态区的资源冷杉野生植株数量为106株(不包括幼苗);其分布区域的海拔1 450~1 900 m,土壤为山地黄棕壤,年平均温度9.5~14.5℃,年均降雨量1 218~2 018 mm,年均相对湿度79.2%~85.6%;现有种群的群落结构完整,具有明显的乔灌草分层;年龄结构存在不合理现象,不同种群的胸径树高差异显著(P<0.05)。结合现存资源冷杉存在的更新繁育问题,从增加种群数量、改善种群群落结构与年龄结构三个方面提出了资源冷杉种群的保育对策,为南方地区资源冷杉种群的保护提供参考。

关键词：资源冷杉种群年龄结构保育对策湖南南山国家公园

微合金化对Al-Cu-Mg合金时效行为的影响

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特种铸造及有色合金 2005年第12期25卷 756-758页

作者：张琳闵光辉冯刚于化顺山东大学山东电力研究院

以微合金化元素对AlCuMg合金常规时效析出相的影响为出发点,分析了Ag,Si,Ge,Cd等元素对合金时效行为的影响。结果表明具有:完全改变常规析出相结构,形成新析出相;部分改变常规析出相结构,提高析出相的强化效果;促进析出相析出3种作用。... 详细信息

以微合金化元素对AlCuMg合金常规时效析出相的影响为出发点,分析了Ag,Si,Ge,Cd等元素对合金时效行为的影响。结果表明具有:完全改变常规析出相结构,形成新析出相;部分改变常规析出相结构,提高析出相的强化效果;促进析出相析出3种作用。分析了采用微合金化方法提高AlCuMg合金热强性所存在的问题,并对发展趋势进行了展望。

关键词： Al-Cu-Mg合金时效强化错配度热稳定性共簇

Zr对Al-Zn-Mg-Cu合金组织和性能的影响

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特种铸造及有色合金 2007年第5期27卷 380-381页

作者：孙立明于化顺闵光辉张静山东大学材料科学与工程学院

研究了Zr对Al-Zn-Mg-Cu合金显微组织和力学性能的影响。结果表明,添加少量Zr可以细化合金铸态组织,并且在热挤压过程中抑制再结晶。在固溶时效过程中,可以促进第二相粒子的析出,从而使基体中析出均匀弥散第二相粒子。T6状态下,未加Zr的... 详细信息

研究了Zr对Al-Zn-Mg-Cu合金显微组织和力学性能的影响。结果表明,添加少量Zr可以细化合金铸态组织,并且在热挤压过程中抑制再结晶。在固溶时效过程中,可以促进第二相粒子的析出,从而使基体中析出均匀弥散第二相粒子。T6状态下,未加Zr的合金其抗拉强度仅为600MPa,伸长率为10.5%;而加Zr后其抗拉强度超过650MPa,伸长率达到12.3%。

关键词：力学性能 Al—Zn—Mg—Cu合金 Zr