期刊文献+
共找到4篇文章
< 1 >
每页显示 20 50 100
金属合金等温相变的体激活能及相变机制 Ⅰ.钢的中温(贝氏体)等温相变 被引量:6
1
作者 康沫狂 张明星 +1 位作者 刘峰 朱明 《金属学报》 SCIE EI CAS CSCD 北大核心 2009年第1期25-31,共7页
钢的中温(贝氏体)等温处理获得的上、下贝氏体和粒状组织,都具有各自独立的C曲线;在转变初期均能获得单一的组织,而在转变的中、后期通常可获得相邻两组织的复合体.必须用单一组织和Arrhenius关系求相变产物的体激活能.将体激活能、组... 钢的中温(贝氏体)等温处理获得的上、下贝氏体和粒状组织,都具有各自独立的C曲线;在转变初期均能获得单一的组织,而在转变的中、后期通常可获得相邻两组织的复合体.必须用单一组织和Arrhenius关系求相变产物的体激活能.将体激活能、组织形貌和体自由能曲线相结合可诠释下述论点:下或上贝氏体是碳原子扩散控制下在奥氏体中的贫碳或极贫碳区,进行"军队型"(队列式)原子无扩散马氏体样切变相变;而粒状组织是碳原子扩散控制下在奥氏体中的最贫碳区,发生"平民型"(非队列式)原子无扩散界面控制相变. 展开更多
关键词 贝氏相变 体激活能 粒状组织 粒状贝氏 马氏样切变 界面控制相变
下载PDF
金属合金等温相变的体激活能及相变机制 Ⅱ.β黄铜等温相变 被引量:1
2
作者 康沫狂 张明星 +1 位作者 刘峰 朱明 《金属学报》 SCIE EI CAS CSCD 北大核心 2009年第1期32-36,共5页
与钢相似,β黄铜等温处理获得的片状α_1(贝氏体)和棒状α都具有自己的C曲线;各转变初期均能获单一相,而转变中、后期通常可获相邻两相的复合体.必须用单一相和Arrhenius关系求相变产物的体激活能.用体激活能、相的形貌和体自由能变化... 与钢相似,β黄铜等温处理获得的片状α_1(贝氏体)和棒状α都具有自己的C曲线;各转变初期均能获单一相,而转变中、后期通常可获相邻两相的复合体.必须用单一相和Arrhenius关系求相变产物的体激活能.用体激活能、相的形貌和体自由能变化相结合能可诠释下述论点:片状α_1(贝氏体)是溶质原子扩散控制下母相β′中的贫溶质区,进行"军队型"原子无扩散马氏体样切变相变;棒状α是溶质原子扩散控制下母相β′中的最贫溶质区,发生"平民型"原子无扩散界面控制相变. 展开更多
关键词 片状α1(贝氏) 棒状α 体激活能 马氏样切变 界面控制相变 β黄铜
下载PDF
The X-linked mental retardation gene PHF8 is a histone demethylase involved in neuronal differentiation 被引量:16
3
作者 Jihui Qiu Guang Shi +5 位作者 Yuanhui Jia Jing Li Meng Wu Jiwen Li Shuo Dong Jiemin Wong 《Cell Research》 SCIE CAS CSCD 2010年第8期908-918,共11页
Recent studies have identified mutations in PHF8, an X-linked gene encoding a JmjC domain-containing protein, as a causal factor for X-linked mental retardation (XLMR) and cleft lip/cleft palate. However, the underl... Recent studies have identified mutations in PHF8, an X-linked gene encoding a JmjC domain-containing protein, as a causal factor for X-linked mental retardation (XLMR) and cleft lip/cleft palate. However, the underlying mechanism is unknown. Here we show that PHF8 is a histone demethylase and coactivator for retinoic acid receptor (RAR). Although activities for both H3K4me3/2/1 and H3K9me2/1 demethylation were detected in cellularbased assays, reeombinant PHF8 exhibited only H3K9me2/1 demethylase activity in vitro, suggesting that PHF8 is an H3K9me2/1 demethylase whose specificity may be modulated in vivo. Importantly, a mutant PHF8 (phenylalanine at position 279 to serine) identified in the XLMR patients is defective in enzymatie activity, indicating that the loss of histone demethylase activity is causally linked with the onset of disease. In addition, we show that PHF8 binds specifically to H3K4me3/2 peptides via an N-terminal PHD finger domain. Consistent with a role for PHF8 in neuronal differentiation, knockdown of PHF8 in mouse embryonic carcinoma P19 cells impairs RA-induced neuronal differentiation, whereas overexpression of the wild-type but not the F279S mutant PHF8 drives PI9 cells toward neuronal differentiation. Furthermore, we show that PHF8 interacts with RAR~ and functions as a coactivator for RARa. Taken together, our results suggest that histone methylation modulated by PHF8 plays a critical role in neuronal differentiation. 展开更多
关键词 PHF8 histone demethylase COACTIVATOR XLMR neuronal differentiation
下载PDF
Effect of Chemical Doping and Ion Implantation on Cond uctivity of Poly(p-phenylene vinylene) Derivatives 被引量:1
4
作者 LI Bao-ming WU Hong-cai LIU Xiao-zeng LI Xiao-qi GAO Chao 《Semiconductor Photonics and Technology》 CAS 2005年第3期188-191,共4页
The surface conductivity of poly [ 2-methoxy-5-(3'-methyl) butoxy]-p-phenylene vinylene (PMOMBOPV) films doped with FeCl3 and H2SO4 by chemical method and implanted by N^+ ions was studied and the comparison of ... The surface conductivity of poly [ 2-methoxy-5-(3'-methyl) butoxy]-p-phenylene vinylene (PMOMBOPV) films doped with FeCl3 and H2SO4 by chemical method and implanted by N^+ ions was studied and the comparison of environmental stability of conductive behavior was also investigated. The energy and dose of N^+ ions were in the rang 15~35 keV and 3. 8×10^15~9. 6×10^16 ions/cm^2, respectively. The conductivity of PMOMBOPV film was enhanced remarkably with the increases of the energy and dose of N^+ ions. For example, the conductivity of PMOMBOPV film was 3. 2×10^-2S/cm when ion implantation was performed with an energy of 35 keV at a dose of 9. 6 × 10^14 ions/cm^2 , which was almost seven orders of magnitude higher than that of film unimplanted. The environmental stability of conductive behavior for ionimplanted film was much better than that of chemical doped films. Moreover, the conductive activation energy of ion-implanted films was measured to be about 0.17 eV. 展开更多
关键词 Ion implantation Chemical doping Poly[2-methoxy-5-(3'-methyl)butoxy]-p-phenylene vinylene Surface conductivity Conductive activation energy
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部