Now showing items 866-885 of 2359

    • N-(2-羟基-1-萘甲酰胺基)-N'-苯基硫脲的合成及对汞离子的识别 

      吴粦华; 陈瑶函 (2010)
      设计合成了用于识别汞离子的ICT荧光传感分子n-(2-羟基-1-萘甲酰胺基)-n’-苯基硫脲(1),通过红外光谱、核磁共振谱和质谱表征了其结构。利用其荧光性质研究了该物质对几种重金属离子的识别性质,初步探讨了其结合模式。实验表明:在50%水-乙腈介质中主体分子1表现出对Hg2+良好的选择性,其结合比为1∶2。
    • N-乙基壳聚糖的单晶 

      董炎明; 入江聪; 吴玉松; 周雪松; 阮永红; 赵雅青; 王惠武 (2003-05-30)
      用光固化法制备N 乙基壳聚糖/聚丙烯酸复合膜.在复合膜中观察到单晶和悬挂着单晶片的微纤.单晶的长和宽约为300~400nm,比常见的晶粒尺寸小得多.与通常单晶的极稀溶液制备条件不同,该单晶是在复合膜中形成的.水的诱导结晶作用和体系的高浓度形成了一种几乎是无限缓慢的结晶条件,单晶正是由于这样条件才能得以形成.
    • N-乙基壳聚糖的针状结晶 

      董炎明; 樱井谦资; 吴玉松; 近藤幸江 (2002-09-20)
      在N 乙基壳聚糖的甲酸溶液浇铸膜中观察到高分子少有的针状晶体 .从球晶经后结晶得到的针状晶体为长条矩形 ,典型尺寸为~ 5 0 μm× 2~ 5 μm× 1~ 2 μm ,高分子链平行于晶体长轴 .针状晶体首先出现在球晶的核心处 ,继而出现在球晶微纤每个树枝状分叉处 ,最后才遍布球晶各处 .针状晶体可以看成是高分子伸直链结晶的一种 .浇铸膜吸潮实际上形成了超浓溶液 (浓度 >80wt% ) ,从而分子链可以运动而后结晶成针状晶体
    • N-烷基壳聚糖玻璃化转变温度的研究 

      董炎明; 阮永红; 赵雅青; 毕丹霞; 杨柳林; 葛强 (2005-11-15)
      采用差示扫描量热(DSC)法和热释电流(TSC)法研究了N-烷基壳聚糖的玻璃化转变行为.DSC法中采用二次扫描以消除溶剂和热历史的影响,并利用物理老化方法来增强N-烷基壳聚糖在DSC曲线上的玻璃化转变区域的热焓吸热峰,以克服DSC法的不灵敏性.两种研究方法的结果一致表明,三种N-烷基壳聚糖的玻璃化转变均发生在110~150℃温区内;取代的柔性烷基越大,玻璃化转变温度(Tg)越低;但N-甲基壳聚糖例外,其Tg略高于壳聚糖,空间阻碍在这里起决定的作用.
    • N-烷基壳聚糖的合成及其溶致液晶行为 

      吴玉松; 李珺; 黄剑莹; 陈羚; 董炎明 (2001-11-30)
      合成了一系列具有不同取代基甲基、乙基、丙基、丁基的壳聚糖衍生物——N烷基壳聚糖,通过控制反应物摩尔比获得了一系列不同取代度的产物.不同取代基及不同取代度的衍生物均具有溶致液晶性,考察了同一碳链不同取代度和相近取代度不同碳链长度的衍生物对其液晶临界行为的影响.结果表明:同一碳链长度时,取代度对临界浓度的影响不大;而当取代度相近时,随着碳链长度增加,临界浓度也随之增大.此结果与Onsager和Flory的刚性棒理论相符.粉末X射线衍射实验 ...
    • N-烷基壳聚糖的羽毛状结晶 

      董炎明; 赵雅青; 王惠武; 阮永红 (2003-06-25)
      将N-甲基壳聚糖或N-乙基壳聚糖的甲酸溶液在高真空中浇铸成膜.然后将浇铸膜在25℃和65%相对湿度的环境中结晶化得到羽毛状结晶.这种羽毛状结晶不同于低真空处理的浇铸膜内生长的球晶.除了形态不同外,双折射符号也完全不同,前者是负的,而后者是正的.羽毛状结晶应是树枝状结晶的一种,但前者的晶带是弯曲的,而后者的晶带基本上是直的.
    • N-苄基壳聚糖的合成和液晶性表征 

      董炎明; 吴玉松; 王勉; 阮永红; 邱蔚碧; 许聪义; 汪剑炜 (2001-02-10)
      合成了新的液晶性壳聚糖衍生物—— N-苄基壳聚糖 ,N-苄基壳聚糖 /二氯乙酸浓溶液呈现液晶相 .用偏光显微镜测得形成液晶有序的临界浓度为 9% (重量百分数 ) .在溶液的红外光谱中 ,二氯乙酸的羰基吸收谱带 1738cm-1在相变时位移到 1731cm-1.利用这一突变测得 N-苄基壳聚糖的临界浓度为 10 % ,与光学显微镜法基本相符 .
    • N-马来酰化壳聚糖的结晶形态 

      王惠武; 董炎明; 赵雅青; 毛微; 毕丹霞 (2004-11-30)
      采用间歇法合成了N 马来酰化壳聚糖,用FTIR和1H NMR测定其化学结构,并进一步用偏光显微镜、扫描电子显微镜研究其结晶形态.研究发现,在N 马来酰化壳聚糖的N,N 二甲基甲酰胺溶液浇铸膜中,先出现常见的树枝晶,然后观察到在树枝晶的末端生长出针状晶体和片状晶体两类不同的结晶形态,针状晶体最长为200μm,片状晶体的宽度平均约为20μm.对于针状晶体,分子链方向为轴向,而对于片状晶体分子链垂直于晶片的长轴方向.
    • Na-5(NH4)Mn-3 B9P6O33(OH)(3) center dot 15H(2)O 

      Lin, Z. S.; Huang, Y. X.; Prots, Y.; Zhao, J. T.; Kniep, R.; 黄雅熙 (2008-12)
      The overall hexagonal framework of the title compound, pentasodium ammonium trimanganese(II) borophosphate sesquihydrate, consists of tube-like borophosphate anions, (1)(infinity){[B(3)P(2)O(11)(OH)](4-)}, made up of ...
    • NaBF(4) as a hygrothermal durability enhancer for glass fibre reinforced polypropylene composites 

      Zhuang, R. C.; Liu, J. W.; Plonka, R.; Huang, Y. X.; Maeder, E.; 黄雅熙 (2011-08-19)
      The long term performance of composite materials is highly desired for their expanding application range. Tuning the interphase properties has been proven to be a practical way to enhance the performance of composites. In ...
    • Nanoporous titanium borophosphates with rigid gainesite-type framework structure 

      Zhou, Yan; Hoffmann, Stefan; Menezes, Prashanth W.; Carrillo-Cabrera, Wilder; Huang, Ya-Xi; Vasylechko, Leonid; Schmidt, Marcus; Prots, Yurii; Deng, Jin-Feng; Mi, Jin-Xiao; Kniep, Ruediger; 宓锦校 (2011)
      Nanoporous titanium borophosphates have been synthesized which exhibit a rigid gainesite-type framework of polyhedra. The open-framework character is supported by the reversibility of de-and rehydration processes.
    • Nanoscale silica capsules ordered on a substrate: Oxidation of nanocellular thin films of poly(styrene-b-dimethylsiloxane) 

      Li, L.; Yokoyama, H.; 李磊 (2006)
      This research was partially funded by the Project on Nanostructured Polymeric Materials of New Energy and Industrial Technology Development Organization. L.L. thanks the Japan Society for the Promotion of Science for a fellowship.
    • Nanostructured Hybrid Polymer Networks From In Situ Self-Assembly of RAFT-Synthesized POSS-Based Block Copolymers 

      Deng, Yuanming; Bernard, Julien; Alcouffe, Pierre; Galy, Jocelyne; Dai, Lizong; Gerard, Jean-Francois; 戴李宗 (2011-10-15)
      A series of well-defined hybrid block copolymers PMACyPOSS-b-PMMA and PMAiBuPOSS-b-PMMA exhibiting high POSS weight contents have been synthesized by RAFT polymerization and further studied as modifiers for epoxy thermosets ...
    • Nanowire-Based Polypyrrole Hierarchical Structures Synthesized by a Two-Step Electrochemical Method 

      Ge, Dongtao; Huang, Sanqing; Qi, Rucai; Mu, Jing; Shen, Yuqing; Shi, Wei; 葛东涛 (2009-08-03)
      A simple two-step electrochemical method is proposed for the synthesis of nanowire-based polypyrrole hierarchical structures. In the first step, microstructured polypyrrole films are prepared by electropolymerization. Then, ...
    • Near-net shaping of microwave ceramics by gel-casting with carrageenan 

      Liu, W.; Wang, Y. X.; Xiong, Z. X.; Pan, W; Gong, JH; 熊兆贤 (2007)
      Single carrageenan and combinations of carrageenan with other polysaccharides, including locust bean gum and konjak gum, are applied to form green bodies of microwave ceramics by gel-casting technique. Similar dielectric ...
    • Neutralization reaction in synthesis of carbon materials for supercapacitors 

      Wen Yan; Zhaohui Meng; Mingye Zou; Hao Miao; Fangxing Ma; Rui Yu; Wu Qiu; Xiang Yang Liu; Naibo Lin (2019-11-25)
      Abstract(#br)We have prepared nitrogen and oxygen enriched hierarchically porous carbon (NOHPC) based on a concept of neutralization reaction. The reactant of KOH and the reaction product of KCl mixed in soybean flour acts ...
    • New cobalt-based intermetallic compound Co2VMn with B2 structure and phase equilibria in the Co-V-Mn ternary system 

      Ruan, J.J.; Wang, C.P.; Yang, S.Y.; Kainuma, R.; Liu, X.J.; 王翠萍; 刘兴军 (Elsevier Ltd, 2014 Decem)
      The phase equilibria in the Co-V-Mn ternary system, the magnetic properties and the phase stability of the new ternary intermetallic compound Co 2VMn were investigated by means of electron probe microanalyzer, X-ray ...
    • New mechanism and improved kinetics of hydrogen absorption and desorption of Mg(In) solid solution alloy milling with CeF 3 

      H.C. Zhong; H.J. Lin; X.J. Lu; C.Y. Cao; C. Chen; J.J. Sun (2019-09-06)
      Abstract(#br)This paper presents improving the hydrogen absorption and desorption of Mg(In) solid solution alloy through doped with CeF 3 . A nanocomposite of Mg 0.95 In 0.05 -5 wt% CeF 3 was prepared by mechanical ball ...
    • Ni-Al-Sn三元系在800和1000℃时的相平衡(英文) 

      刘兴军; 吴超; 杨木金; 杨水源; 张锦彬; 黄艺雄; 王翠萍 (2019-10-15)
      采用电子探针显微分析和X射线衍射分析等方法研究了Ni-Al-Sn三元系在800和1000℃时的相平衡。结果表明:(1) Ni-Al-Sn三元系在800和1000℃时均未发现三元化合物;(2) Ni-Al侧存在Ni Al、Ni3Al、Al3Ni和Al3Ni2 4个化合物,800℃时,Sn在Ni Al和Ni3Al中的固溶度分别为3.1 at%和14.7 at%,在1000℃时分别为3.0 at%和8.0 at%。而Sn在Al3Ni和Al3N ...
    • Ni-B amorphous alloy nanoparticles modified nanoporous Cu toward ethanol oxidation in alkaline medium 

      Zhang, Shu-Jin; Zheng, Yi-Xiong; Yuan, Lin-Shan; Zhao, Li-Hua; 赵莉华; 李华 (ELSEVIER SCIENCE BV, 2014)
      Nanoporous Cu (NPC) prepared by dealloying CuZn alloy is used as an economic substrate for the fabrication of Ni-B alloy (Ni-B/NPC) by ultrasonic-assisted electroless technique. The results of scanning electron microscopy ...