X.L.Zhao1)
,
T.L.Guo2)
,
M.Ohkohchi3)
,
T.Okazaki3)
,
S.Iijima and Y.Ando3) 1) Japan Science and Technology Corporation
,
Department of Physics
,
Meijo University
,
Shiogamaguchi1 501
,
Tempaku ku
,
Nagoya 468 8502
,
Japan 2) Scientific Research Department
,
Shenyang University
,
Wanghuanan Street21
,
Dadong District
,
Shenyang 110044
,
China 3) Department of Physics
,
Meijo University
,
Shiogamaguchi 1 501
,
Tempaku ku
,
Nagoya 468 8502
,
Japan$
金属学报(英文版)
Multiwalled carbon nanotubes ( MWNTs) were prepared by DCarc dischargein hydrogen gas, and werethermally purified byinfrared radiation in air. The morphology of pristineand purified MWNTs was observed by scanning electron microscope ( SEM) , and the crys tallinestructureand perfection wereinvestigated by high resolution transmission electron mi croscope( HRTEM) and Raman spectrometer. Itcameto the conclusion thatthese MWNTs possessed a high degreeof graphitization and very narrow centralchannel(about1 0 nm indiameter) , giving risetotheappearanceof breathing modesfor MWNTs.
关键词:
multiwalled carbon nanotubes
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null
,
null
,
null
,
null
周元鑫
,
夏源明
材料科学与工艺
doi:10.3969/j.issn.1005-0299.2001.04.001
利用MTS810试验机和自行研制的冲击拉伸试验装置对T300/Al复合丝实施了不同应变率下的拉伸试验,获得了材料从0.001 s-1到1 300 s-1应变率范围内完整的应力应变曲线.结果表明:T300/Al是一种应变率敏感复合材料,随着应变率的提高,材料的拉伸强度、失稳应变均相应提高,具有明显的应变率强化效应和动态韧性现象,这主要是由铝基体的应变率强化效应和应变率历史效应引起的.根据材料在不同应变率下的试验结果以及对其不同变形阶段机理的分析,提出了弹塑性复合丝束模型,并由此建立了相应的应变率相关的一维统计损伤本构方程,模型拟合结果与试验结果一致.
关键词:
T300/A1复合丝
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应变率效应
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统计模型
尹绍江
,
辛凤英
,
齐长发
,
陈礼斌
金属世界
doi:10.3969/j.issn.1000-6826.2006.04.018
本文结合唐钢FTSR生产线的实际生产工艺参数,利用Gleeble 3500C热模拟机,分别研究了单道次不同变形温度、变形速率(50%压下率)对高强低合金T510L钢变形抗力和奥氏体微观组织演变的影响及两道次(R1→R2)连续变形后奥氏体微观组织演变.实验表明通过高温大压下量的变形,完全可使该钢种充分发生动态再结晶,细化奥氏体晶粒度.
关键词:
FTSR
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变形温度
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变形速率
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动态再结晶
余历军
,
雷闫盈
,
陈立宇
机械工程材料
doi:10.3969/j.issn.1000-3738.2007.12.005
采用四点弯曲试样在高频疲劳试验机上对铝基复合层板进行了疲劳试验,采用直流电势法测量裂纹长度,用扫描电镜和光学显微镜观察其疲劳断口及疲劳裂纹形貌,通过对比性试验,考察了组元性能错配和界面结合强度对复合板L-T取向疲劳裂纹扩展行为的影响,并用断裂力学理论对其进行了初步分析.结果表明:性能错配的复合双层板两侧面的疲劳裂纹扩展通过界面产生牵扯作用,扩展速率相对于整体材料发生变化,近似符合混和定则;界面对层合板L-T取向疲劳性能的韧化作用以分层韧化为主,结合强度不同,产生的影响也不一样.
关键词:
复合层板
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疲劳裂纹
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界面结合强度
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性能错配
Chinese Physics Letters
The magnetic properties of 1 T-TaS2 and 1 T-Fe-0.07 Ta-0.93 S-2 have been studied, Experimental results show that the phase transition temperature of 1 T-TaS2 is a function of the magnetic field, At low temperatures, both compounds are in a mixed state of charge density wave -spin density wave due to the coherent superposition of antiferromagnetic coupling.
关键词:
density
Physical Review B
The magnetic properties and phase transitions of 1T-TaS2 and 1T-Fe0.07Ta0.93S2 have been studied in the interval of 1.5-300 K and over the range of 100 Oe-60 kOe. Experimental results show that at high temperatures the compounds are in a diamagnetic state and the commensurate-charge-density-wave-triclinic-nearly-commensurate transition temperature of 1T-TaS2 decreases with increasing magnetic field. The amount of variation is a function of the magnetic field. At low temperatures both 1T-TaS2 and 1T-Fe0.07Ta0.93S2 are in a paramagnetic state owing to the localized moments that come from the single Anderson-Mott localization state. The curves of magnetization versus temperature do not follow the Curie law or Curie-Weiss law, but can be described fairly well as M = M(0) + gamma T--n. The fitting parameters of experimental curves show that a part of the neighboring moment appears as antiferromagnetic coupling due to exchange interaction between the moments. The magnetic-field dependence of magnetization exhibits a complicated feature at low temperature. It shows that the compounds may undergo a phase transition at the maximum value of magnetization and then they are probably in a mixed charge-density-wave-spin-density-wave (CDW-SDW) state or SDW state due to the coherent superposition of the antiferromagnetic coupling.
关键词:
metal-insulator-transition;density-wave domains;high magnetic-fields;charge-density;doped 1t-tas2;coexistence;microscopy;systems;silicon;2h-tas2
何志宏
,
李宝华
,
唐众民
,
鄢江武
兵器材料科学与工程
doi:33-1331/TJ.20110905.2223.006
采用3种规格的搅拌头进行2A70-T6铝合金T型接头搅拌摩擦焊试验,并对焊缝横截面进行观察以及焊缝抗拉强度的测试.结果表明:焊缝中前进侧过渡区的金属变化急剧,拉长的晶粒成流线状分布,返回侧过渡区的金属变化缓和,由焊核区细小晶粒缓慢过渡至母材较大的晶粒;随着搅拌针根部直径的增加,焊核的宽度也增大;为了获得无缺陷的接头,焊接速度增大时,顶锻压力必须协同增大,随着顶锻压力的增大,焊缝的抗拉强度也增大.
关键词:
2A70-T6
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铝合金
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T型接头
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搅拌摩擦焊
Communications in Theoretical Physics
For the first time, by taking into account all the irreducible representations and their components in the electron-phonon interaction (EPI) as well as all the levels and the admixtures of wavefunctions within d(3) electronic configuration, the values of parameters in expressions of Raman and optical-branch terms of thermal shifts (TS) due to EPI for three levels, T-4(2) band and T-4(1) band of ruby have been evaluated; the contributions to TS of T-4(2) and T-4(1) broad bands from thermal expansion have also been. calculated; and then, the TS of the peak energies of 'T2 and 4 Ti broad bands have been calculated. The results are in satisfactory agreement with observed data. The values of single-electron reduced matrix elements representing the strengths of EPI of T-4(2) and T-4(1) bands have respectively been determined. For TS of the peak energies of T-4(2) and T-4(1) bands, it is found that the contribution to TS from the second-order term in EPI Hamiltonian is dominant; TS due to EPI of acoustic branches are over two times as much as those of optical branches, and both of them increase rapidly with temperature; the neighbor-level term is insignificant; the contribution to TS from thermal expansion is specially important, and all the three terms of TS of T-4(2) or T-4(1) band axe red shifts.
关键词:
crystal fields;optical spectral bands;electron-phonon interaction;thermal expansion;thermal shift;theoretical calculations;high-pressure;field;spectroscopy;spectra
苏艳蓉
,
柴立元
,
杨志辉
,
尤翔宇
,
朱咏华
中国有色金属学报
以pannonibacter phragmitetusT1菌作为生物吸附剂,研究细菌代谢活性、培养时间、溶液pH值、菌体用量、温度、吸附时间、初始金属浓度等因素对其吸附重金属pb2+的影响,并进一步研究吸附机理.结果表明,培养12h的灭活T1菌体在pb2+浓度为150 mg/L、pH值为6、T1菌添加量为0.5 g/L、温度为30℃的条件下,对Pb2+的最大吸附量为68.35 mg/g;灭活T1菌对重金属Pb2+的吸附过程较快,90 min即达到吸附平衡,pb2+的吸附符合Pseudo-second order模型和Langmuir等温吸附模型.结合红外光谱分析,灭活pannonibacter phragmitetus T1 菌对Pb2+是表面吸附,羟基和酰胺基是与Pb2+络合反应的主要基团.
关键词:
pannonibacter phragmitetus T1菌
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铅离子
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吸附条件
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吸附机理
材料科学技术（英文）
Structure and magnetostriction of Dy1-xPrxFe2 (0 less than or equal to x less than or equal to 0.5), Dy0.6Pr0.4(Fe1-yTy)(2) (0 less than or equal to y less than or equal to 0.6), and Tb1-zPrz(Fe0.4Co0.6)(2) (0 less than or equal to z less than or equal to 1.0) alloys (T=Co, Ni) have been investigated. It is found that the matrix of the alloys Dy1-xPrxFe2 is a single phase (Dy, Pr)Fe-2 with MgCu2-type structure and the second phase is (Dy, Pr)Fe-3 when x less than or equal to 0.2. The amount of (Dy, Pr)Fe-3 phase increases with increasing Pr content and becomes the main phase when x=0.4. The matrix of Dy1-xPrxFe2 is found to be the (Dy, Pr)(2)Fe-17 phase with Th2Zn17-type structure when x=0.5. It is found that the amount of the cubic Laves phase (Dy, Pr)(Fe, Co)(2) in the Dy0.6Pr0.4(Fe1-yCoy)(2) increases with increasing Co concentration when 0 less than or equal to y less than or equal to 0.6. The substitution of Ni for Fe is nearly not favorable for the formation of the cubic Laves phase (Dy, Pr)(Fe, Ni)(2) in (Dy1-xPrx)Fe-2. The matrix of (Tb1-zPrz)(Fe0.4Co0.6)(2) is a (Tb, Pr)(Fe, Co)(2) phase with the MgCu2-type cubic Laves structure and a second phase of small amount is (Tb, Pr)(Fe, Co)(3) phase when z less than or equal to 0.2, z=0.5 and 1.0. When 0.22 exhibits a peak when x=0.3. The lambda(parallel to) - lambda(perpendicular to) for Dy0.6Pr0.4(Fe1-yMy)(2) (M=Co, Ni) and Tb1-zPrz (Fe0.4Co0.6)(2) is also examined.
关键词:
