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1.
化学气相淀积法合成氮化铝薄膜及其工艺设计   总被引:1,自引:0,他引:1  
对AlBr3-NH3-N2体系化学气相淀积法合成A1N膜进行了热力学分析和工艺设计,研究了在不同淀积温度和体系总压时,体系中主要气态物种的平衡分压和A1N膜的理论淀积速率与源温和载气流量的关系,并与微波等离子体化学气相淀积A1N膜的实验结果进行了比较。  相似文献   

2.
用非平衡热力学耦合模型研究了金刚石在C-H-Cl体系中的生长,计算所得C-H-Cl体系的金刚石生长的相图与大量实验结果符合良好,通过热力学分析讨论了氯的添加对提高金刚石薄膜生长速率及其质量的影响以及降低淀积温度的作用。  相似文献   

3.
采用等离子体激活的化学气相淀积装置系统,以钇的β-二酮类螯合物(Y(DPM)_3)为源物质,于低温低压等离子体条件下,在单晶硅、兰宝石和石英玻璃衬底上生长了Y_2O_3薄膜。对生长层进行形貌观察、表面组成分析、X-射线衍射结构分析和光学性能测试。结果表明,淀积层形貌和结构与衬底性质有关。Y_2O_3生长层与单晶硅和兰宝石衬底存在确定的外延关系,在无定形石英玻璃衬底上的生长层则是附着良好的非晶态膜。  相似文献   

4.
本文使用铝支持的铁催化剂,通过化学气相淀积方法合成了虫型碳纳米纤维;并把它以3:2的质量比与玻璃粉混合,借助松油醇的粘结,制备了薄膜传感器。使用扫描电镜和透射电镜对虫型碳纳米纤维,铁催化剂和传感器薄膜进行了形貌分析。最后在室温和常压下,采用新的检测方法在低电压(0-1伏)条件下进行了传感器的气敏测试,分析了它对氨气的灵敏性等特性。实验结果证实:在低浓度氨气条件下(0.175 mg/m3-0.35 mg/m3),基于虫型碳纳米纤维的薄膜传感器具有极高的灵敏性;经过反复的实验,证实薄膜传感器具有很高的稳定性,极快的反应时间(0.05 s)和恢复时间(1 min)。实验结果说明虫型碳纳米纤维是极好的气敏材料。  相似文献   

5.
Ge-132的羧酸阴离子与稀土离子螯合配位,生成3:1型配合物,在配合物中,Ge-132的GeO3/2基团水解为Ge(OH)3,并且不参与稀土配位,系列稀土离子配合物的结构性质基本相同,在50℃,pH值为6的水溶液中,该配合物选择性地催化5’-AMP或5‘-dAMP的磷酯键水解断裂、生成相应的核苷和磷酸,而不影响碱基与戌糖之间的苷键。  相似文献   

6.
用胆甾液晶冠醚气相色谱固定相分离取代苯位置异构体   总被引:2,自引:1,他引:2  
卿笑天  唐英 《分析化学》1997,25(6):648-651
以胆甾型苯并-15-冠-5涂渍于硅烷化102白色担体作为一种新的GC上,柱温在125℃以下(固体固定相)、125℃以上(液体固定相)及由182℃降至125℃以上(冠醚液晶固定相)三种情况下,对几种取代苯位置异构体的分离效果进行了比较研究,并探讨了分离机理。  相似文献   

7.
陈用烈  郑牧 《应用化学》1994,11(2):27-30
用改装的国产CDR-1型DSC仪研究了苯基缩水甘油醚(PGE)和环氧树脂(E-51)以双-[4-(二苯硫翁基)苯基]硫-二-六氟化磷引发的光聚合。研究了引发剂浓度,光强,温度等因素对聚合反应的影响。对于PGE,聚合速率与引发剂浓度的0.90次方,与光强的0.78次方成比例。对于E-51,聚合速率与引发剂浓度的0.87次方式成比例,而与光强的关系则比较复杂。温度分别超过70℃(对PGE)或80℃(对  相似文献   

8.
Owing to the unique structure, the superior physical and chemical properties, the super strong mechanical performances, and so on, carbon nanotubes have attracted the attention of researchers all over the world. In this article, the basic properties and the main production processes of carbon nanotubes are introduced in brief, and the progress of applied research for carbon nanotubes is reviewed.  相似文献   

9.
用非平衡热力学耦合模型研究了金刚石在CHCl体系中的生长,计算所得CHCl体系的金刚石生长的相图与大量实验结果符合良好.通过热力学分析讨论了氯的添加对提高金刚石薄膜生长速率及其质量的影响以及降低淀积温度的作用.  相似文献   

10.
本文概述了GaN基发光材料的基本特性和GaN基器件的应用领域及未来的发展前景。简述了GaN基材料的生长技术,着重介绍了金属有机化学气相淀积法。  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.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

14.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

15.
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   

16.
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   

17.
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   

18.
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   

19.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).  相似文献   

20.
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.  相似文献   

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