苏际
,
杨丽莎
,
Reed Nicholas Liu
,
林鸿飞
催化学报
doi:10.1016/S1872-2067(14)60039-5
可再生生物质资源的开发与利用能够缓解化石燃料产生的温室气体对环境的负面影响.在生物质燃料制备过程中联产高附加值化学品能大幅提高生物质炼制的经济性.愈创木酚是常见的木质纤维素快速热解产物.本文研究了低温液相氧化愈创木酚制备马来酸,并重点考察了催化剂添加量、pH值、反应时间和反应温度等反应条件的影响.研究发现,在钛硅沸石-过氧化氢碱溶液氧化反应体系中(80°C, pH=13.3),20-30 mol%的愈创木酚可以选择性转化为马来酸.同时初步探讨了愈创木酚氧化开环转化为马来酸的反应机理.
关键词:
生物质
,
木质素
,
愈创木酚
,
氧化
,
马来酸
,
TS-1
,
过氧化氢
,
羧酸
材料科学技术（英文）
The 304 stainless steel with nanostructured surface layer was successfully obtained by using the high-energy shot peening (HESP) method. The internal friction and Young's modulus of this kind of surface nanocrystallized material were dynamically measured by means of the vibrating reed apparatus. The results implied that different treatment time could induce different microstructure and distribution characteristic of defects in this kind of materials. It is also demonstrated that there is a transition layer between the nano-layer on surface and the coarse grain region inside. The transition layer obviously has certain influence on the overall mechanical properties.
关键词:
surface nanocrystallization;internal friction;high-energy shot peening;iron;behavior
徐卫兵
,
戈明亮
,
何平笙
应用化学
doi:10.3969/j.issn.1000-0518.2001.09.011
用熔融插层法制备聚甲醛/蒙脱土纳米复合材料,用X射线衍射研究聚甲醛及复合材料的微观结构,表明复合材料是纳米复合材料.用DSC法研究其非等温结晶行为,对所得数据分别用Jeziorny法、Ozawa法和Liu法进行处理.结果表明,Jeziorny法和Liu法处理非等温结晶过程比较理想.聚甲醛及聚甲醛/有机蒙脱土纳米复合材料的结晶活化能分别为334.6和196.9 kJ/mol,说明有机蒙脱土的加入,降低了聚甲醛的结晶活化能,且t1/z缩短,起到了异相成核的作用.
关键词:
聚甲醛
,
蒙脱土
,
纳米复合材料
,
非等温结晶动力学
王平华
,
徐国永
应用化学
doi:10.3969/j.issn.1000-0518.2004.08.007
用熔融复合法制备聚丙烯/凹凸棒土纳米复合材料,用DSC法研究其非等温结晶行为,对所得的数据分别用Jeziorny法、Ozawa法和Liu法进行处理.结果表明,Jeziorny法和Liu法处理非等温结晶过程比较理想.聚丙烯及聚丙烯/凹凸棒土纳米复合材料的结晶活化能分别为194.1和162.8 kJ/mol,表明凹凸棒土的加入,降低了聚丙烯的结晶活化能,且t1/2缩短,起到了异相成核作用.
关键词:
聚丙烯
,
凹凸棒土
,
纳米复合材料
,
非等温结晶动力学
Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing
In this paper, 304 stainless steel and pure Fe specimens, which were processed by high-energy shot peening (HESP) and ultrasonic shot peening (USP) respectively, were studied by the internal friction method. Measurements were carried out on a vibrating reed apparatus. The change of internal friction and elastic modulus shows that the treatment duration of specimen is not accompanied by the corresponding persistent increase of internal friction and elastic modulus. There is a transition layer from the top surface to the inside of the materials. Young's modulus of surface shows obviously a fluctuation along the depth profile. The phenomena have never been shown by other measurement methods. The microstructure change should be related to some basic mechanism of surface layer formation. It may also explain why the improvement of mechanical properties in surface nanocrystallized materials does not simply correspond to the duration time of severe deformation. (C) 2003 Elsevier B.V. All rights reserved.
关键词:
internal friction;Young's modulus;surface nanostuctured material;iron;nanocrystallization;304-stainless-steel;behavior
Scripta Materialia
A recent comment on a previously published paper addressed the invalid explanation of the off diagonal interdiflusion coefficients of the beta-Ni(Al,Cr) phase in the Ni-Cr-Al system according to the symmetric property of the thermodynamic matrix. In this paper, the experimental data presented by Hou et al. was reanalyzed and the interdiffusion coefficient matrix was estimated again. The results of the analysis have been discussed in terms of a brief reply to the comments of Liu and Liang. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
关键词:
Diffusion;Intermetallic compound;Ni-Cr-Al
邓超
,
邵玮
,
李春忠
高分子材料科学与工程
采用元机纳米锑掺杂二氧化锡(ATO)和有机聚醚酯(PEE)协同提高聚时苯二甲酸乙二酯(PET)的抗静电性能,合成了聚对苯二甲酸乙二酯-聚醚酯/锑掺杂二氧化锡纳米复合材料(PET-PEE/ATO).使用Czawa方程和Liu-Mo方程研究了PET-PEE/ATO纳米复合材料的非等温结晶过程.Ozawa方程研究发现,在非等温结晶过程中,PET、PET-PEE、PET/ATO、PET-PEE/ATO的成核性能依次提高.Liu-Mo方程发现,ATO和PEE的加入分别促进了异相成核作用和加快了结晶生长,PET-PEE/ATO结晶成核性能最好,结晶速率最快.
关键词:
聚对苯二甲酸乙二酯
,
有机聚醚酯
,
无机纳米锑掺杂二氧化锡
,
纳米复合材料
,
非等温结晶动力学
王浩
,
刘国权
金属学报
doi:10.3321/j.issn:0412-1961.2008.07.001
以MacPherson-Srolovitz提出的三维个体晶粒长大拓扑依赖速率方程以及三维晶粒组织的晶粒尺寸-晶粒面数间的抛物线型统计关系为基础,导出了相应的描述三维准稳态晶粒尺寸分布的函数族.采用纯Fe实验数据以及顶点法、基元演化法.相场模型和Monte Carlo法进行了验证,结果表明,函数族中峰值左偏的函数适合三维准稳态晶粒尺寸分布的定量表述.将该函数与Liu等提出的2种三维准稳态晶粒尺寸分布函数进行的对比表明:此3种函数的解析表达形式有所不同,但其曲线图在一定条件下相互吻合.此外,MacPherson-Srolovitz三维拓扑依赖速率方程、Hillert三维速率方程及Yu-Liu三维速率方程尽管表达形式不同均能较好地反映三维正常晶粒长大的动力学规律.
关键词:
三维晶粒长大
,
准稳态晶粒尺寸分布
,
长大速率方程
,
计算机仿真
王浩
,
刘国权
,
秦湘阁
金属学报
采用Potts模型Monte Carlo方法对3种现存的三维个体晶粒长大速率拓扑依赖性
方程进行了仿真验证. 结果表明, Rivier速率方程认为晶粒
体积变化率dVf/dt与晶粒面数f成线性关系, 与仿真
结果明显不符, 不适用于描述三维晶粒长大过程的动力
学. 当晶粒面数f≥8时, Yu-Liu速率方程和
MacPherson-Srolovitz速率方程均与仿真结果很好吻合,
表明这两者均可以用来定量描述三维晶粒长大过程的动力学；当
f＜8时, 这两个方程均与仿真结果有显著差异.
关键词:
三维晶粒长大
,
topology-dependent grain growth rate equation
