检索结果-南通市图书馆

Journal of Materials Science & Technology 2018年第7期34卷 1222-1228页

作者： lijie zuo Bing Ye Jian Feng Xiangyang Kong Haiyan Jiang Wenjiang Ding National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200240 China Institute of Materials for Mobile Energy School of Materials Sdence and Engineering ShanghaiJiao Tong University Shanghai 200240 China

The relationship between the as-cast microstructure and mechanical properties of the ***- 2Ni-0.8Mg alloys produced by permanent mold casting （PMC） and high pressure die casting （HPDC） is investigated. The alloys in both PMC and HPDC consist of Al, Si, A15 Cu2 MgsSi6, Al3 CuNi, and Al Cu4Ni phase. However, the microstructure of the HPDC alloy is significantly refined. Compared to the PMC alloy, the ultimate tensile strength of the HPDC alloy is significantly increased from 244 MPa to 310 MPa, while the elongation shows a reverse trend at room temperature. At low stress and temperature range, slight variations of stress exponent and activation energy indicate that the minimum creep rate is controlled by the grain boundary creep. Then the minimum creep rate is higher for the specimen with the smaller grain size, where grain boundary creep is the dominant creep mechanism. At high stress region, the stress exponent for the PMC alloy and HPDC alloy is 5.18 and 3.07, respectively. The different stress exponents and activation energies measured at high stress and high temperature range indicates that the creep mechanism varies with the casting technologies.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.

关键词： Microstructure Tensile properties CreepHigh pressure die casting

Effects of Zr,Ti and Sc additions on the microstructure and mechanical properties of Al-0.4Cu-0.14Si-0.05Mg-0.2Fe alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2018年第12期34卷 2316-2324页

作者： Jian Feng Bing Ye lijie zuo Ruijuan Qi Qudong Wang Haiyan Jiang Rong Huang Wenjiang Ding Jie Yao Chuntao Wang National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversitySchool of Materials Science and EngineeringShanghai Jiao Tong University Key Laboratory of Polar Materials and Devices Ministry of EducationEast China Normal University Ningbo Heli Mould Technology Co. Ltd

The evolution of microstructure and mechanical properties of Al-0.4 Cu-0.14 Si-0.05 Mg-0.2 Fe（wt.%）alloys, micro-alloyed with Zr, Ti and Sc, were investigated. The addition of 0.2%Zr to base alloy accelerates the precipitation of Si-rich nano-phase in α-Al matrix, which plays an important role in improving the mechanical properties of an alloy. The tensile strength increases from 102 MPa for the base alloy to 113 MPa for the Zr-modified alloy. Adding 0.2%Zr + 0.2%Ti to base alloy effectively refines a-Al grain size and accelerates the precipitation of Si and Cu elements, leading to heavy segregation at grain *** further adding 0.2%Sc to Zr + Ti modified alloy, the segregation of Si and Cu elements is suppressed and more Si and Cu precipitates appeared in α-Al matrix. Accompanied with the formation of coherent Al;Sc phase, the tensile strength increases from 108 MPa for the Zr + Ti modified alloy to 152 MPa for the Sc-modified alloy. Due to excellent thermal stability of Al;Sc phase, the Sc-modified alloy exhibits obvious precipitation hardening behavior at 350℃, and the tensile strength increases to 203 MPa after holding at 350 ℃ for 200 h.

关键词： Micro-alloying Microstructure Mechanical properties Al_3Sc Grain size

Biosynthesis of antibiotic chuangxinmycin from Actinoplanes tsinanensis

在线全文

学校读者我要写书评

暂无评论

Acta Pharmaceutica Sinica B 2018年第2期8卷 283-294页

作者： Yuanyuan Shi Zhibo Jiang Xingxing Li lijie zuo Xuan Lei Liyan Yu Linzhuan Wu Jiandong Jiang Bin Hong Key Laboratory of Biotechnology of Antibiotics the National Health and Family Planning Commission (NHFPC) Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College

Chuangxinmycin is an antibiotic isolated from Actinoplanes tsinanensis CPCC 200056 in the1970 s with a novel indole-dihydrothiopyran heterocyclic skeleton. Chuangxinmycin showed in vitro antibacterial activity and in vivo efficacy in mouse infection models as well as preliminary clinical *** the biosynthetic pathway of chuangxinmycin has been obscure since its discovery. Herein, we report the identification of a stretch of DNA from the genome of A. tsinanensis CPCC 200056 that encodes genes for biosynthesis of chuangxinmycin by bioinformatics analysis. The designated cxn cluster was then confirmed to be responsible for chuangxinmycin biosynthesis by direct cloning and heterologous expressing in Streptomyces coelicolor M1146. The cytochrome P450 CxnD was verified to be involved in the dihydrothiopyran ring closure reaction by the identification of seco-chuangxinmycin in S. coelicolor M1146 harboring the cxn gene cluster with an inactivated cxn D. Based on these results, a plausible biosynthetic pathway for chuangxinmycin biosynthesis was proposed, by hijacking the primary sulfur transfer system for sulfur incorporation. The identification of the biosynthetic gene cluster of chuangxinmycin paves the way for elucidating the detail biochemical machinery for chuangxinmycin biosynthesis, and provides the basis for the generation of novel chuangxinmycin derivatives by means of combinatorial biosynthesis and synthetic biology.

关键词： Chuangxinmycin Actinoplanes tsinanensis Biosynthesis gene cluster Heterologous expression Cytochrome P450 Seco-chuangxinmycin C–S bond formation Sulfur incorporation

在线全文

学校读者我要写书评

暂无评论

脑内血肿微创碎吸术的护理对策探讨

中国卫生标准管理 2016年第1期7卷 261-262页

作者：左李洁四川省达州市中西医结合医院重症监护室 635000

目的探讨脑内血肿微创碎吸术的护理对策。方法选取2013年3月-2015年5月我院收治的行脑内血肿微创碎吸收术患者72例进行分组研究,按照1：1比例分为对照组（n=36,采用常规护理）和干预组（n=36,采用护理干预）,对比2组护理效果。结果干预... 详细信息

目的探讨脑内血肿微创碎吸术的护理对策。方法选取2013年3月-2015年5月我院收治的行脑内血肿微创碎吸收术患者72例进行分组研究,按照1：1比例分为对照组（n=36,采用常规护理）和干预组（n=36,采用护理干预）,对比2组护理效果。结果干预组治愈率、死亡率优于对照组,差异具有统计学意义（P〈0.05）。结论临床护理干预可提高脑内血肿微创碎吸术治愈率,降低死亡率,改善患者生存质量。

关键词：护理对策脑内血肿微创碎吸术应用效果

100 t EAF-LF-VD-CC流程生产非调质钢的工艺实践

在线全文

学校读者我要写书评

暂无评论

特殊钢 2013年第4期34卷 46-48页

作者：黄周华左立杰颜丽华苏钢集团技术中心苏州215151

非调质钢S38MnSiV(/%:0.41～0.45C、0.55～0.70Si、1.40～1.55Mn、≤0.025P、≤0.025S、0.10～0.20Cr、0.11～0.15V、0.012 0～0.020 0N)的生产流程为40%铁水+废钢-100 t EAF-LF-VD-160 mm×160 mm～260mm×340 mm CC工艺。通过控制电弧炉出钢终点[C]0.15%～0.30%,出钢[P]≤0.012%,出钢温度1 640～1 680℃,高碱度渣精炼,控制钢液铝含量,VD后喂氮化锰线控制钢液中氮含量等工艺措施,8炉生产结果表明,钢中氧含量-[O]5×10^(-6)～11×10^(-6),[H]1.2×10^(-6)～1.5×10^(-6),[N]135×10^(-6)～180×10^(-6);260 mm×340 mm铸坯热孔成Φ140 mm棒材经880℃120 min正火风冷,580℃240 min回火空冷后的抗拉强度R_m为870～925 MPa,屈服强度R_(el)为560～605 MPa,其冶金质量满足标准要求。

关键词： S38MnSiV非调质钢 100t EAF-LF-VD-CC流程工艺实践

在线全文

学校读者我要写书评

暂无评论

稀土元素对高熵合金组织和性能的影响

材料导报 2024年第S02期38卷 438-446页

作者：贺毅强钱思成顾航王英杰冯文尚峰左立杰江苏海洋大学机械工程学院江苏连云港222006 上海电机学院机械学院上海200240

随着制造业的快速发展,对高性能材料的需求也越来越高,在此背景下合金的开发与研究变得尤为重要。高熵合金因具有高强度、良好的塑性和韧性、耐热性、软磁性能、高耐腐蚀性等诸多优点,被广泛应用在航空发动机、化学工程和运输、燃料电... 详细信息

随着制造业的快速发展,对高性能材料的需求也越来越高,在此背景下合金的开发与研究变得尤为重要。高熵合金因具有高强度、良好的塑性和韧性、耐热性、软磁性能、高耐腐蚀性等诸多优点,被广泛应用在航空发动机、化学工程和运输、燃料电池和储能等。而稀土元素与高熵合金的结合对其组织与性能的影响还待进一步探究,目前对高性能的稀土高熵合金的种类和制备工艺仍待开发。本文主要从细晶强化、固溶强化、析出强化和加工硬化四大强化方式,阐述了稀土元素添加到高熵合金中引起微观结构和性能的变化,剖析了其特有的强化机制,并对目前研究中所存在的问题进行了说明以及对未来发展方向进行了展望。

关键词：高熵合金细晶强化固溶强化析出强化加工硬化

基于代谢组学分析白虎汤拆方对热应激蛋鸡保护作用研究

在线全文

学校读者我要写书评

暂无评论

黑龙江畜牧兽医 2024年第19期 92-96,122,123页

作者：许舒娅张勤左利杰李向辉李利红河南牧业经济学院动物医药学院郑州450046

为了分析饲喂白虎汤拆方前后热应激蛋鸡的血浆代谢物变化,明确其血浆差异代谢物及代谢通路,试验将180只51周龄海兰褐蛋鸡随机分为3组,每组3个重复,每个重复20只蛋鸡;对照组及热应激组饲喂基础日粮,白虎汤拆方组在基础日粮中添加0.75%的... 详细信息

为了分析饲喂白虎汤拆方前后热应激蛋鸡的血浆代谢物变化,明确其血浆差异代谢物及代谢通路,试验将180只51周龄海兰褐蛋鸡随机分为3组,每组3个重复,每个重复20只蛋鸡;对照组及热应激组饲喂基础日粮,白虎汤拆方组在基础日粮中添加0.75%的白虎汤拆方干粉,对照组蛋鸡饲养舍内按照正常温度(26±1)℃饲养,热应激组及白虎汤拆方组于第14天将饲养温度调至(32±1)℃。第21天试验结束后,收集蛋鸡血液样本,利用超高压液相-四极杆-飞行时间串联质谱(UPLC-Q-TOF-MS/MS)分析蛋鸡血浆代谢物质谱,并对所采集的数据进行主成分分析及正交偏最小二乘法分析。结果表明:共鉴定出14个差异代谢物,其中7个可作为白虎汤拆方缓解蛋鸡热应激的潜在标志物,白虎汤拆方对氨酰-t RNA生物合成,半胱氨酸和甲硫氨酸代谢,甘氨酸、丝氨酸和苏氨酸代谢,甘油磷脂代谢,精氨酸和脯氨酸代谢,亚油酸代谢,苯丙氨酸、酪氨酸和色氨酸生物合成,酪氨酸代谢,硫胺素代谢途径影响较大。说明白虎汤拆方主要是通过影响蛋鸡的氨基酸代谢及脂质代谢来发挥保护热应激蛋鸡作用。

关键词：热应激白虎汤拆方蛋鸡代谢组学液质联用色谱技术

在线全文

学校读者我要写书评

暂无评论

稀土对X70管线钢腐蚀行为的影响

特殊钢 2012年第5期33卷 49-50页

作者：杨吉春左立杰赵丙新聂亚丽内蒙古科技大学材料与冶金学院包头014010

试验用X70管线钢(/%:0.12C、0.20Si、1.60Mn、0.005P、0.005S、0.10V、0.10Nb、0～0.15RE)用10kg真空感应炉冶炼。采用电化学和失重分析法研究了微量稀土对X70管线钢在0.1 mol/L Na_2SO_4水溶液中的腐蚀行为。试验结果表明,微量稀土可... 详细信息

试验用X70管线钢(/%:0.12C、0.20Si、1.60Mn、0.005P、0.005S、0.10V、0.10Nb、0～0.15RE)用10kg真空感应炉冶炼。采用电化学和失重分析法研究了微量稀土对X70管线钢在0.1 mol/L Na_2SO_4水溶液中的腐蚀行为。试验结果表明,微量稀土可降低管线钢腐蚀电流i_(corr),改善腐蚀形貌。随着稀土加入量的增加,腐蚀电流减小,当钢中的RE含量由0增加至0.10%时腐蚀速率由7.43μg/(cm^2·day)降至0.29μg/(cm^2·day)。稀土的最适宜加入量是0.10%。

关键词：稀土腐蚀性能 X70 管线钢

GCr15轴承钢LF含BaO精炼渣系脱硫研究

在线全文

学校读者我要写书评

暂无评论

特殊钢 2012年第3期33卷 15-17页

作者：杨吉春赵丙新左立杰聂亚丽内蒙古科技大学材料与冶金学院包头014010

通过Mo丝高温电阻炉采用正交实验法研究了LF精炼渣系(/%:28.75～58.05CaO、12.50～32.43Al_2O_3、0～15BaO、8～20SiO_2、6MgO、10CaF_2)的成分对高碳铬轴承钢GCr15(/%:0.99C、1.45Cr、0.034S)脱硫的影响。结果表明,当(CaO)/(Al_2O_3)=2.5,(SiO_2)=14%,(BaO)由0增至8%时,精炼渣对钢液的脱硫率增加,(BaO)由8%增至15%时脱硫率降低;当(BaO)=7.5%,(SiO_2)=14%时,随(CaO)/(Al_2O_3)增加,精炼渣的脱硫率增加;当(BaO)=7.5%,(CaO)/(Al_2O_3)=2.5时,随(SiO_2)增加,精炼渣的脱硫率降低。钢液最佳脱硫效果的LF精炼渣组成为:6%～10%(BaO),3.5～4.0(CaO)/(Al_2O_3),8%～12%SiO_2。

关键词： GCr15轴承钢 LF 精炼渣 BaO 脱硫

Y-Mg复合变质对SS400钢显微组织的影响

在线全文

学校读者我要写书评

暂无评论

稀有金属 2010年第3期34卷 336-340页

作者：王福龙杨吉春刘南邓小和赵凤光左立杰内蒙古科技大学材料与冶金学院内蒙古包头014010

利用Y-Mg合金(m(Y)∶m(Mg)=1∶3)复合变质处理碳素结构钢SS400,研究了Y-Mg复合变质对SS400钢显微组织的影响。结果表明,原来比较粗大的SS400钢板条马氏体束,经过Y-Mg复合变质处理后变得相对细小;随着钢中Y-Mg含量的增加,试验钢的珠光体... 详细信息

利用Y-Mg合金(m(Y)∶m(Mg)=1∶3)复合变质处理碳素结构钢SS400,研究了Y-Mg复合变质对SS400钢显微组织的影响。结果表明,原来比较粗大的SS400钢板条马氏体束,经过Y-Mg复合变质处理后变得相对细小;随着钢中Y-Mg含量的增加,试验钢的珠光体显微硬度明显增大,从未经Y-Mg处理前的平均148.5 HV上升到Y-Mg处理后的平均188.2 HV,增幅为26.7%。未经Y-Mg复合处理的试验钢中珠光体呈短粗状不规则片层形貌,经过Y-Mg复合处理的试验钢中珠光体片层间距、渗碳体厚度减小。随着Y-Mg含量的增加,试验钢的珠光体片间距从335.4 nm减小到了135.3 nm,说明Y-Mg复合变质处理对SS400钢珠光体片层间距的增厚起到了抑制作用,试验钢中珠光体片层间距和渗碳体厚度随着钢中稀土、镁含量的升高而逐渐减小。对Y-Mg复合处理前后的试验钢的晶粒数进行测定和比较:单位面积的晶粒数由1330增加到4569,晶粒度级别由7~7.5增大到9~9.5。随着Y-Mg含量的增高,试验钢每平方毫米晶粒数明显增多,表明Y-Mg复合处理能明显细化晶粒。

关键词： Y-Mg SS400 显微组织