首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 140 毫秒
1.
AFM诱导正十八硫醇在金基底上的选择性生长   总被引:1,自引:0,他引:1  
扫描探针显微镜(SCCnningPF0boMICCOSCOPy,SPM)由于其极高的空间分辨能力和高度的可控性,已成为纳米尺度加工的有力工具[‘·’j.自Schneir等[’j报道原子级平整金基底的制备和用装备An针尖的扫描隧道显微镜(ScanningTunnelingMicroscoPy,STM)在基底上制备金纳米点以来,有关在All和HOPG等基底上制备由金点构成的任意图案的方法及用导电原子力显微镜(AtomicForceM卜roscopy,AFM)在HOPG和St基底上制备金点阵的工作已有许多报道[‘·’‘.用导电AFM和TaPPingmodeAFM”,’‘对St进行直接氧化可在其表面加…  相似文献   

2.
低温相合成是水热合成化学的重要特征之一[’j,因此,水热合成对低温相功能材料的开发和应用研究有着十分重要的意义.水热晶化法合成的固体电解质材料具有结晶度高、均匀性好等特点,更有利于材料的制备[’-‘j.低温型质子导体在气体传感器和股分离及股反应器方面有着广泛的应用前景,材料体系多含水或羟基化合物.为此,我们以开发新型低温相质子导体为目的,在K。0-Sb。0。-Y。O。-H。O体系中开展了新型低温相的水热合成研究,本文报道了K3Sbo3Y408·6HZO新型低温相的水热合成与表征.1实验方法以分析纯KOH、Y刀。和C。H…  相似文献   

3.
涂亮亮  贾春阳 《化学进展》2010,22(8):1610-1618
导电聚合物(聚苯胺,聚吡咯,聚噻吩)作为超级电容器电极材料的研究引起了人们广泛的兴趣,该类材料制备的超级电容器具有成本低、容量高、充放电时间短、环境友好和安全性高等优点。本文综述了近年来基于导电聚合物及其与无机材料(碳材料/金属氧化物材料)复合所得电极材料在超级电容器中的应用进展,指出具有纳米结构导电聚合物材料及导电聚合物与无机纳米材料的复合是超级电容器电极材料研究的重要发展方向。  相似文献   

4.
水溶性双金属催化剂在硝基化合物加氢反应中的协同效应   总被引:3,自引:0,他引:3  
采用水溶性催化剂在两相体系下进行的催化反应既保持了均相催化剂的优点,又可通过简单的相分离达到使产物与催化剂分离的目的[’1.对于水溶性催化剂在两相体系中催化加氢反应,文献中大多采用水溶性铐一瞬、铱一脚和钉一碟络合物为催化剂对a、“不饱和醛、酮、酸等化合物的选择加氢进行考察[’‘.然而对水溶性把一脚络合物催化加氢反应性能研究的报道甚少[‘j.在多相催化中,双(或多)金属的协同效应是常见的现象,但在均相及高分子负载的催化体系中双(或多)金属的协同效应的报道较少[‘].我们曾报道了高分子负载的Pd/RU双…  相似文献   

5.
采用超声波混合、抽滤的方法把多壁碳纳米管(MWCNTs)和乙炔黑混合制备了锂离子电池用复合导电剂浆料,用扫描电子显微镜(SEM)和恒流充放电测试考察了复合导电剂的结构和其作为导电剂对LiCoO2电极放电比容量的影响。SEM的分析结果表明MWCNTs和乙炔黑实现了纳米层次的均匀混合。复合导电剂悬浮液和浆料分别被用作导电剂制成了两种LiCoO2电极,前一种电极为Cathode A,后一种电极为Cathode B,考察了不同MWCNTs含量时,两种电极0.5C第10次放电比容量的差异。实验结果表明,随着MWCNTs含量的增加,两种电极放电比容量的差值增大,说明低含量MWCNTs的复合导电剂浆料是一种理想的锂离子电池导电剂。  相似文献   

6.
聚苯胺-TCNQ复合薄膜的微观结构与电学特性   总被引:3,自引:2,他引:1  
聚苯胺 (PANI)作为高聚物材料 ,具有稳定性好 ,易于合成等优点.它在化学传感器、显示器、光化学电池等光电器件上有着许多潜在的应用前景.目前导电聚苯胺材料的合成、薄膜的制备与表征正在受到人们的重视.由于聚苯胺很难溶于一般的有机溶剂 ,用化学方法通过聚合物溶液用旋涂或自组装的方法成膜具有很大的局限性 ,特别是不易得到实用化的薄膜产物.而用真空蒸发沉积方法制备聚苯胺薄膜却有成膜质量高、易于控制 ,能很好与电子及微电子加工工艺相接轨等优点[1 -3].国外已有一些关于真空蒸发沉积聚苯胺薄膜的研究报导[2 -5],但…  相似文献   

7.
C60接枝聚(N-乙烯基咔唑)的合成、表征及光电导性能   总被引:2,自引:0,他引:2  
自从C60被发现和被制备出来以后,其特殊的结构和独特的物理和化学性质受到各研究领域学者的广泛青睐.聚(N-乙烯基咔唑)(PVK)体系经 C60掺杂后光电导性能有很大幅度提高.但掺杂体系不稳定,因而限制了对该类材料的应用.为了克服这种缺点,我们尝试用各种简单的方法把C60化学键合到高分子链中,制备具有光电导性能的C60高分子衍生物. 最近,唐本忠[1]和 Patil[2]等分别用常规的自由基聚合方法,将C60接枝到聚合物分子主链上,我们已研究了不含导电高分子的C60共聚物的光电导性能[3],本文采用…  相似文献   

8.
漆原钴法制备四羰基钴钠及羰基化反应   总被引:4,自引:0,他引:4  
李光兴  刘勇 《应用化学》1998,15(1):116-118
谈基钻的传统制备方法“提在高温高压下,由合成气与钻盐反应制备出CO。(CO)s,再经某些化学处理方法制备Na[CO(CO)。I,但其反应条件苛刻,操作手续繁杂,成本高,不利于大量推广应用.制备四谈基钻盐方法,还有KCN转化法[”,NaBH。还原法‘’‘等,但各种方法均有一定缺点.我们报道了Ranev-Ni催化剂催化合成Na[Co(CO)。」的新方法*”‘.此方法收率高,反应条件温和,具有较好的应用前景,但仍存在Ni、CO分离的问题.进一步改进催化剂、降低成本、高效地合成N迁C。(CO)。」仍是解决问题的关键.为此,我们探讨…  相似文献   

9.
设计和构筑有效的三维导电网络结构对于优化储能电极材料的性能具有重要意义.石墨烯独特二维结构所具有的超高电荷传导、极大的表面负载空间和可形成三维孔(层)隙骨架结构等特性为制备多样化的复合电极材料提供了基础.本文介绍了近年来基于石墨烯的三维网络结构复合电极材料的构筑及其在电化学储能(如锂离子电池、锂硫电池)应用中的研究进展,结合本实验室的研究工作,着重介绍了石墨烯基复合电极材料结构设计的科学原理,讨论了几种石墨烯复合结构,并对未来石墨烯复合结构体系的构筑及其应用作了展望.  相似文献   

10.
PVC膜修饰粉末微电极的研制及应用   总被引:8,自引:0,他引:8  
聚合物具有催化、导电和选择分离等功能,将其与电极合为一体作为新的电极材料,可为改善固体电极的灵敏度、选择性和重现性提供一种新的手段[1,2].我们用流延法[3]制得PVC选择性渗透膜,覆盖于粉末微电极表面,制成了PVC膜修饰粉末微电极.该电极性能稳定...  相似文献   

11.
用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.  相似文献   

12.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

13.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.  相似文献   

14.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

15.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

16.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

17.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

18.
19.
《Tetrahedron》2014,70(21):3377-3384
The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.  相似文献   

20.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号