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951.
水热合成CdS纳米晶体的形貌控制研究 总被引:4,自引:0,他引:4
研究了水热合成CdS纳米晶体形貌的化学控制,选择不同的络合试剂为模板,研究其对水热合成CdS纳米晶体形貌的影响.实验发现若以络合试剂乙二胺、甲胺为模板时,产品CdS晶体的形貌分别为(20~30) nm×(200~600) nm和(40~50) nm×(200~600) nm尺寸的纳米棒;而以络合试剂吡啶、 氨为模板时,产品CdS晶体的形貌分别为平均尺寸约30 nm和20 nm的纳米颗粒.用XRD、TEM、XPS、PL和Raman光谱等技术对所得CdS纳米棒进行了表征.同时对水热合成CdS纳米晶体形貌的模板控制机制进行了探讨,提出了一种水热合成CdS纳米棒的络合物结构诱导生长机理. 相似文献
952.
"Energy chemistry" was approved as one of the chemistry majors for undergraduate by the Ministry of Education in 2015. Based on the ideas and ways of emerging engineering education, this paper hereby proposed some of constructive suggestions on the training objectives, graduation requirements, curriculum system, teaching contents, teaching staff and conditions for development of "energy chemistry" major. 相似文献
953.
长链脂肪酸LB膜的X射线衍射研究 总被引:4,自引:0,他引:4
利用Langmuir-Blodgett技术制备了硬脂酸、花生酸及其混合酸的多层LB膜。用低角X射线衍射研究了它们的周期结构,硬脂酸和花生酸的LB膜在2θ=0.8°~23°的范围内分别出现13个和12个布拉格衍射峰,由此计算了它们的等同周期。用模型计算了它们衍射峰的强度,得到了与实验一致的衍射强度奇偶起伏的结果。在混合酸的LB膜中,可以观察到等同周期随混合比变化的规律。 相似文献
954.
Reactions of ketenes generated from alpha-diazoketones with a series of acyclic and cyclic imines were investigated under both microwave and photoirradiation conditions. The results indicate that the zwitterionic azabutadiene-type intermediates yielded from imines and ketenes undergo a conrotatory ring closure exclusively to produce beta-lactams. It is notable that no Woodward-Hoffmann product was found under the ultraviolet irradiation. The photoirradiation-induced Staudinger reaction shows a different stereoselectivity from the electrocyclic reaction of substituted 1,3-butadiene. 相似文献
955.
六氢吡啶和氨形成的氢键团簇C5H10NH(NH3)n(n=1~3)结构的从头算研究 总被引:2,自引:0,他引:2
在RHF/6-31G(d)水平下,对C5H10NH(NH3)n(n=1~3)氢键团簇的平衡构型进行了从头算研究,优化得到各种可能的平衡构型.C5H10NH(NH3)为线型氢键结构,而C5H10NH(NH3)2为三元环结构,C5H10NH(NH3)3为四元环结构.在MP2/6-31G(d)//B3LYP/6-31G(d)水平下,对最稳定构型C5H10NH(NH3)n(Ⅰ)(n=1~3)的分子轨道进行布居分析,并且对相应的占据轨道进行指认.C5H10NH(NH3)n(Ⅰ)(n=1~3)垂直电离势的计算结果表明,形成氢键团簇后,分子的垂直电离势降低. 相似文献
956.
A method for the determination of fluoride by reversed-phase, high-performance liquid chromatography (RP-HPLC) is described. Fluoride, La3+ and alizarin complexone form F-La3+-alizarin complexone ternary complex, which is separated from the matrix on a RP, Ultrasphere C18 column (250 × 4.6 mm, 5 μm) using methanol-water (19:81, v/v) mobile phase at 1.00 mL min?1; detection at 568 nm. The calibration graph was linear from 1.0–150 ng mL?1 for fluoride with a correlation coefficient: 0.9993 (n=6). The detection limit was 0.2 ng mL?1. The method was successfully applied to the determination of fluoride in river and tap water. Recovery was: 94–102%, RSD in the range: 1.9 –3.6%. 相似文献
957.
Anusuya Choudhury Fuqiang JinDengjin Wang Zhe WangGuoyou Xu Dieu NguyenJohn Castoro Michael E PiercePat N Confalone 《Tetrahedron letters》2003,44(2):247-250
Anti-HIV agent β-F-ddA (1) has been synthesized starting from readily available non-sugar, (S)-(+)-Dihydro-5-(hydroxymethyl)-2-(3H)-furanone (4). A highly syn-stereoselective fluorination of the hydroxy lactone 2 generates the key intermediate fluorolactone 5 in a short and concise synthetic sequence. Reduction of 5 followed by bromination generates the aglycon which is glycosylated to generate F-ddA by amination and deprotection. Steric bulk of the 5-protecting group has minimal effect on the steric course of glycosylation. 相似文献
958.
M. G. Fan Y. C. Liang Y. F. Ming J. X. Chen T. Ye Q. Y. Zhang B. A. Xu S. Jin 《Research on Chemical Intermediates》1998,24(9):961-971
Photophysical behavior of spiro[1,3,3-trimethylindolino-2,3′-naphtho[2,1-b]-1,4-oxazine] (SP1) and spiro[1,3,3,2′-tetramethylindolino-2,3′-naphtho[2,1-b]-1,4-oxazine] (SP2) were studied. The fluorescent species and their spectra of SP1 and SP2 in polar solvents (acetonitrile and methanol) and non-polar solvent (cyclohexane) were investigated. The fluorescence decay
in polar solvents was studied by picosecond time-correlated single photon counting. In most cases, fluorescence decay obeyed
triexponential decay kinetics. The major fluorescent species is an excited intermediate which has similar conformation as
its precursor (1
SP
*) formed after the bond cleavage between spirocarbon and oxygen in oxazine ring. The effects of molecular structure and solvent
polarity on fluorescence spectra and fluorescence decay lifetime were studied. 相似文献
959.
A white substance was got by directly heating TiSi powder on Ti foil, under Ar+O
2 atmosphere. ED, EDX, SEM and HRTEM studies reveal that the white substance consists of amorphous SiO
2 nanowires of smooth surface and uniform diameter (40-90 nm). X-ray-induced luminescent emission experiment shows that two
broad peaks are at 430 and 570 nm. A one-dimensional growth mechanism, on the basis of the one-dimensional thermal flow during
nanowire formation, is discussed. 相似文献
960.