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131.
Alexi K. Nedeltchev 《Tetrahedron》2010,66(48):9319-9326
A new class of conjugated quinoline amines was prepared by Friedländer condensation reaction. They showed stable amorphous state below glass transition temperatures as examined by differential scanning calorimetry and X-ray diffraction studies. Additionally, they exhibited fluorescence properties in the blue to green region of visible spectrum in both solution and solid state. Their fluorescence quantum efficiencies in chloroform were in a broad range of 3-45%. Interestingly, they formed stable fibers with micrometer thickness drawn from melt, which were characterized by polarizing optical microscopy and scanning electron microscopy studies. 相似文献
132.
用蒙特卡罗方法实现了对各种不同条件下晶体光输出特性的模拟研究,和实验结果比较符合得足够好,因而可用以预言新的现象和实验结果。结合光输出的实验测量,可以确定绝对的光子产额。研究还表明,封装材料和耦合剂对光收集效率影响很大,选用具有漫反射性的封装材料将有利于光的收集效率 相似文献
133.
Johan B. Malherbe 《固体与材料科学评论》1994,19(2):55-127
Several phenomena occur on the surface of a solid when being bombarded by energetic ions. A short general review is given of the major ion-solid interactions on compound semiconductor surfaces. An in-depth discussion is presented of the total sputtering yields of component semiconductors. For this discussion, GaAs is assumed to be the prototype compound semiconductor because most experimental measurements exist for GaAs. To exclude any chemical effects in the sputter yields, only the total sputtering yield data for argon ion bombardment of GaAs are compared with the predictions of the major sputtering theories, with particular attention to the Sigmund theory for linear cascade sputtering. Different proposals of each of the parameters in this theory are presented and compared with the GaAs data. These parameters are the surface binding energy, the nuclear stopping power, and the factor α, which represents the fraction of energy available for sputtering. Use of the different parameters results in a large variation in the predictions. Topics also considered are the angle dependence of the sputtering yields, sputter threshold energy, and channeling effects in the sputter yields of compound semiconductors. Spike sputtering effects are evident in the sputtering yields of GaAs by krypton and xenon ions. 相似文献
134.
Fe(Ⅱ)pyridinebisimine complexes activated with trialkylaluminium or modified methylaluminoxane(MMAO)ascatalysts were employed for the polymerization of butyl methacrylate(BMA).Polymer yields,catalytic activities andmolecular weights as well as molecular weight distributions of BMA can be controlled over a wide range by varying thereaction parameters such as cocatalyst,Al/Fe molar ratio,monomer/catalyst molar ratio,monomer concentration and reactiontemperature used in the polymerization.The catalytic activity of Fe(Ⅱ)complex was 11.1 kg_(polym)/mol_(Fe)h and the highestyield could reach 99.1% under optimum condition. 相似文献
135.
Chen-guang Xu Tai-ning Liang Juan Sun Xiao-zhen Yang State Key Laboratory of Polymer Physics Chemistry Center for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing China 《高分子科学》2001,(5):527-529
A better understanding of a recently raised argument on whether there occurs a structure change during yieldinghas been acquired by using molecular simulation. That is, when monitoring the displacements of all atoms before and afterthe yield, a structure transition does occur, which is the "atomic jump" that coordinates the amount of the atoms in thepolymer and makes a large step beyond~0.05 nm for all those atoms. Results indicate that the complex of polymer chainpacking induces the multiple atomic jumps around the yield point. This explains why polymers have a broader yielding peak. 相似文献
136.
Synthesis, photophysical and photochemical properties of aryloxy tetra-substituted gallium and indium phthalocyanine derivatives 总被引:1,自引:0,他引:1
The synthesis, photophysical and photochemical properties of the tetra-substituted aryloxy gallium(III) and indium(III) phthalocyanines are reported for the first time. General trends are described for photodegradation, singlet oxygen, fluorescence, and triplet quantum yields and triplet lifetimes of these compounds. The introduction of phenoxy and tert-butylphenoxy substituents on the ring resulted in lowering of fluorescence quantum yields and lifetimes, and triplet quantum yields, and an increase of kIC, kISC, and kF. Photoreduction of the complexes was observed during laser flash photolysis. The singlet oxygen quantum yields (ΦΔ), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism) ranged from 0.41 to 0.91. Thus, these complexes show potential as Type II photosensitizers. 相似文献
137.
138.
V. P. Kazakov A. I. Voloshin S. S. Ostakhov I. A. Khusainov E. V. Zharinova 《Russian Chemical Bulletin》1997,46(4):699-704
Chemiluminescence (CL) accompanying the decomposition of dispiro(diadamantane-1,2-dioxetane) (1) in acetonitrile solutions of EuIII, GdIII, TbIII, PrIII, and CeIII perchlorates was studied. In the presence of EuIII, TbIII, and PrIII ions, the chemiluminescence spectra contain the luminescence bands of these ions. In the cases of GdIII and CeIII, the chemiluminescence is caused by deactivation of singlet-excited adamantanone (2). The excitation of the lanthanide ion depends on the existence of suitable energy levels at which intracomplex excitation
transfer from the3n,π* of ketone is possible. Chemiluminescence of1 increases in solutions of EuIII and TbIII. The yields of CL and excitation of the lanthanide ions in the decomposition of1 in the1·EuIII and1\TbIII complexes were determined: φEu · =0.013 ± 0.003 and φTb · =0.08±0.02. The fact that the efficiency for the population of the5D4-level of TbIII is higher than that for the5D1 and5D0-levels of EuIII is related to the difference in the energy gap between the triplet level of2 and the excited levels of the lanthanides.
For Part I, see Ref. 1.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 730–735, April, 1997. 相似文献
139.
Susanta K. Sengupta Urvashi Sandhir Nira Misra 《Journal of polymer science. Part A, Polymer chemistry》2001,39(10):1584-1588
Contact glow-discharge electrolysis (CGDE) is an unconventional electrolytic phenomenon in which a plasma is sustained by a direct current (dc) glow-discharge between an electrode and the liquid electrolyte around it. A remarkable feature of CGDE is highly nonfaradaic chemical effects at the glow-discharge electrode. During anodic CGDE of an aqueous electrolyte, non-Faradaic yields originate mainly from reactions triggered by H• and OH• radicals generated in high local concentrations near the anodic plasma/liquid electrolyte interface during the process. The radical-generating potentiality of anodic CGDE was explored for the polymerization of acrylamide in aqueous media. The percentage of monomer conversion, rate of polymerization, charge efficiency, and viscometric average molar mass of the polymers produced were measured as functions of the quantities of electricity passed. The charge efficiency of the polymerization of acrylamide by anodic CGDE was at least 1 order of magnitude higher than that of ordinary electrochemically initiated polymerization. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1584–1588, 2001 相似文献
140.