Materials Literature
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We found that ibuprofen (IPF) became amorphous when the crystalline powder was merely mixed with polyvinylpyrrolidone (PVP), using a test tube mixer, and allowed to stand at appropriate temperatures. The crystallinity of the mixture was evaluated from the X-ray diffraction spectra by Ruland's method. The degree of dec…
Abstract The polymerization of ε‐caprolactone (εCL) initiated with aluminium triisopropoxide (Al(O i Pr) 3 ) trimer ( A 3 ) and/or tetramer ( A 4 ) was studied. The rate of A 3 ⇔︁ A 4 interconversions in the diluted (≤0,1 mol · L ‐1 ) C 6 D 6 , C 6 D 6 /εCL, and THF/εCL solutions were found to be slow, when compared w…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA Generic Approach to Functionalizing Aromatic Polyimides for Second-Order Nonlinear OpticsDong Yu, Ali Gharavi, and Luping YuCite this: Macromolecules 1995, 28, 3, 784–786Publication Date (Print):January 1, 1995Publication History Published online1 May 2002Published inissue…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA Definitive Investigation of the Gas-Phase Two-Center Three-Electron Bond in [H2S-SH2]+, [Me2S-SMe2]+, and [Et2S-SEt2]+: Theory and ExperimentYing Deng, Andreas J. Illies, Mary A. James, Michael L. McKee, and Michael PeschkeCite this: J. Am. Chem. Soc. 1995, 117, 1, 420–428…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetermination of Low Critical Surface Energies of Novel Fluorinated Poly(amide urethane) Block Copolymers. 1. Fluorinated Side ChainsToby M. Chapman, Ramazan Benrashid, Kacey L. Gribbin, and Jonathan P. KeenerCite this: Macromolecules 1995, 28, 1, 331–335Publication Date (Pr…
Diffuse reflectance FTIR spectroscopy has been applied to the study of fundamental CO bond stretching vibrations and their first overtones, and combination modes of copper(I) carbonyls, formed upon CO adsorption on CuNaY zeolite after reduction with CO at 400 °C. The frequencies of the combination modes of copper(I) c…
By reaction of [K(18-crown-6)][N(PPh3)2]2[PMo12O40]·2MeCN 1 and [NBun4]4[S2Mo18O62] with PPh3 in acetonitrile the new compounds [K(18-crown-6)]2[N(PPh3)2]2[HPMo12O40]·8MeCN·18-crown-6 2(18-crown-6 = 1,4,7,10,13,16-hexaoxacyclooctadecane) and [NBun4]5[H3S2Mo18O62]·4MeCN 3 were prepared. Compound 2 contains the two-elec…
A series of synthetic saponites (smectite clays with tetrahedral substitution) have been intercalated by the Al13 polycation followed by pillaring (anchoring of the pillars to the layers on calcination to 500 °C).Even the clays with the highest layer charge have been successfully intercalated and pillared, but the amo…
The synthesis of unsymmetrical, peripherally octa-substituted phthalocyanines which contain a combination of 1,4,7,10-tetraoxaundecyl and hexadecyl or dodecyloxy side-chains is described. These compounds were prepared by mixed phthalonitrile cyclotetramisations or by the self-condensation of an unsymmetrical phthaloni…
Based on a theoretical model proposed for quasi-one-dimensional organic polymer ferromagnets, the spin configuration of \ensuremath{\pi} electrons in a \ensuremath{\pi}-conjugated carbon chain with a single and two side radicals, which contains unpaired electrons, is investigated. The strong electron-phonon interactio…
A bimetallic assembly, [Ni(pn)2]2[Fe(CN)6]ClO4·2H2O, has a two-dimensional square network structure, formed from Fe–CN–Ni(pn)2–NC–Fe linkages, and shows ferromagnetic ordering.
We report measurements of the thermal conductivity \ensuremath{\lambda}(T) of icosahedral ${\mathrm{Al}}_{70}$${\mathrm{Mn}}_{9}$${\mathrm{Pd}}_{21}$ in the temperature range 0.06--110 K. The quasilattice thermal conductivity ${\ensuremath{\lambda}}_{\mathrm{ph}}$ increases monotonically with T in the temperature rang…
We report extended Hückel theory (EHT) band structure calculations for the high-temperature polymorph of α-6T (α-sexithiophene) and C60, two organic materials that have shown promising device characteristics, as the active element in thin-film transistors (TFTs). We also report calculations for α-3T and κ-(ET)2Cu(NCS)…
A large-scale Monte Carlo investigation of the interface between the A-rich and B-rich phase of a partially incompatible binary (AB) symmetric polymer mixture is presented. The bond fluctuation model on the simple cubic lattice at a volume fraction ϕ= 0.5 of occupied lattice sites and chain lengths NA=NB=N= 32 is used…
1H NMR assignments of human ubiquitin (76 amino acids, Mr 8565) have been made by a combination of DQF-COSY, DQF-RELAY, NOESY, DQ, and isotropic mixing experiments. Complete NH, C alpha H, and C beta H assignments were obtained; resonances not yet assigned are the side-chain amides of Q-40, Q-41, Q-49, N-60, and Q-62…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural and Molecular Mechanics Studies on Highly Ruffled Low-Spin (Porphinato)iron(III) ComplexesOrde Q. Munro, Helder M. Marques, Peter G. Debrunner, K. Mohanrao, and W. Robert ScheidtCite this: J. Am. Chem. Soc. 1995, 117, 3, 935–954Publication Date (Print):January 1,…
Protein geranylgeranyltransferase-I (PGGT-I) catalyzes the transfer of the 20-carbon prenyl group from geranylgeranyl pyrophosphate to the cysteine residue near the C-termini of a variety of eukaryotic proteins. Kinetic analysis of homogenous PGGT-I from bovine brain reveals that the reaction follows a sequential path…
Owing to its large molecular size, alkylation of 2,4-di-tert-butylphenol with cinnamyl alcohol does not take plAcc using HY zeolite (pore opening 7.4 Å) as catalyst even after controlled steaming treatment to increase its mesoporosity; by contrast, novel mesoporous aluminosilicate MCM-41 catalyses this reaction giving…
X-ray diffraction (XRD), 27Al magic-angle-spinning (MAS) NMR, N2 adsorption measurements and transmission electron microscopy (TEM) show that the one-dimensional channels of the mesoporous aluminosilicate MCM-41 containing only structural (four-coordinate) aluminium are much shorter in the sample with an Si/Al ratio o…
摘要 利用程序升温脱水——色谱检测(TPD-GC),并配合使用热重分析(TGA),差热分析(DTA)和X射线衍射(XRD)研究手段,系统地考察了一组金属离子交换蒙脱石中水的吸附与脱除.实验结果表明,蒙脱石中吸附水的存在状态和数量均明显地依赖于蒙脱石层间可交换金属离子的数目和水合能力.但是,与通常的理解不同,在任何一种离子交换蒙脱石中,这种吸附水都不可能有与蒙脱石间结合力明显不同的两种存在状态. Abstract 作者及机构信息 宫宝安, 齐少梅 1. 烟台师范学院化学系,烟台264025 Authors and contacts GONG BAO-AN, QI SHAO-MEI 1. 烟台师范学院化学系,烟台264025 参考文献…