共查询到20条相似文献,搜索用时 15 毫秒
1.
Kazuo Suwa Yoshihiro Wada Yoshihiro Kikunaga Keitaro Morishita Akio Kishida Mitsuru Akashi 《Journal of polymer science. Part A, Polymer chemistry》1997,35(9):1763-1768
Pyrolysis of (N-α-isopropoxyethyl)isobutyramide, which was obtained by the reaction of isobutyramide, 2-propanol, and acetaldehyde in the presence of conc. sulfuric acid, produced N-vinylisobutyramide (NVIBA). The free radical polymerization of NVIBA was carried out in various solvents in the presence of a radical initiator. It was found that the polymerizability of NVIBA is similar to that of N-vinylacetamide. The resulting polyNVIBA showed a lower critical solution temperature (LCST) sharply at 39°C. Thermosensitive properties of polyNVIBA were investigated in comparison with poly(N-isopropylacrylamide). © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1763–1768, 1997 相似文献
2.
Fumiko Kimura Tsunehisa Kimura Akira Sugisaki Mamoru Komatsu Hiroaki Sata Eiko Ito 《Journal of Polymer Science.Polymer Physics》1997,35(16):2741-2747
In situ Fourier transform infrared (FTIR) measurements were carried out to elucidate conformation changes occurring during the isothermal melt crystallization of poly(ethylene-2,6-naphthalate) (PEN). Based on the band assignments for the components of the amorphous, α-crystal form, and β-crystal form of PEN in film samples, the in situ data was analyzed in terms of the amorphous- and crystal-trans conformations. It was observed at a higher isothermal crystallization temperature that the formation of amorphous-trans conformations precedes the growth of crystals. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2741–2747, 1997 相似文献
3.
M. Dosch M. G. Weller A. F. Bückmann R. Niessner 《Fresenius' Journal of Analytical Chemistry》1998,361(2):174-178
A flavin adenine dinucleotide-trinitrotoluene derivative (FAD-TNT) was synthesized by coupling N
6-(2-aminoethyl)-FAD covalently to the N-hydroxysuccinimidyl ester of trinitrophenyl-γ-aminobutyric acid and characterized by negative-ion electrospray-ionization
mass spectrometry (ESI-MS) after purification by reversed-phase HPLC. Free FAD-TNT can be detected at very low levels by recombination
with apoglucose oxidase, since the FAD-TNT-glucose oxidase complex is enzymatically active. On the contrary, if FAD-TNT has
been bound by an anti-TNT antibody, the conjugate cannot recombine with apoglucose oxidase any more. Based on these two phenomena,
a homogeneous apoenzyme reactivation immunoassay system (ARIS) was developed for the detection of TNT. No separation step
is needed in this assay. Proportionality between the TNT concentration and enzyme activity was demonstrated with a detection
limit of 5 μg/L TNT.
Received: 5 September 1997 / Revised: 3 December 1997 / Accepted: 9 December 1997 相似文献
4.
W. J. Pullan 《Journal of computational chemistry》1997,18(8):1096-1111
This article describes a parallel real-coded genetic algorithm implemented to find global minimum energy structures of microclusters of non-bonded argon and xenon atoms. Using appropriate genetic operators, the genetic algorithm was able to find minimum energy structures for microclusters of two to twenty atoms, in all possible combinations of argon and xenon. © 1997 John Wiley & Sons, Inc. J Comput Chem 18 :1096–1111, 1997 相似文献
5.
Sun Hang Cho Mu Shik Jhon Soon Hong Yuk Hai Bang Lee 《Journal of Polymer Science.Polymer Physics》1997,35(4):595-598
Copolymers of N,N-dimethylaminoethyl methacrylate (DMAEMA) and acrylamide (AAm) were prepared to demonstrate a temperature-induced phase transition. Poly DMAEMA has a lower critical solution temperature (LCST) around 50°C in water. With copolymerization of DMAEMA with AAm, the LCST shifts to the lower temperature was observed, probably due to the formation of hydrogen bonds between amide and N,N-dimethylamino groups. FT-IR studies clearly show the formation of hydrogen bonds which protect N,N-dimethylamino groups from exposure to water and result in a hydrophobic contribution to the LCST. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys, 35: 595–598, 1997 相似文献
6.
Luminita Ghimici Stela Dragan Florin Popescu 《Journal of Polymer Science.Polymer Physics》1997,35(16):2571-2581
The interaction of several mono-, di-, and trivalent anions with cationic polyelectrolytes having different contents in N,N-dimethyl-2-hydroxypropylen ammonium chloride units (polymer A) or tertiary amine N-atoms and PEG (polymer PEGA) in the main chain was studied by viscosimetric and conductometric measurements. Both methods have shown a stronger interaction for tri- and bi- than for univalent counterions. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35 : 2571–2581, 1997 相似文献
7.
Laura Gagliardi Gian Luigi Bendazzoli Stefano Evangelisti 《Journal of computational chemistry》1997,18(11):1329-1343
We present a method for the direct generation of the lists of strings, suited for integral-driven full-CI (FCI) algorithms. This method generates the string lists each time they are used, and hence sensibly reduces the memory requirements, compared to our previous method that precalculates the lists. It was also extended to permit a truncation of the string space, according to the level of excitation. © 1997 by John Wiley & Sons, Inc. J Comput Chem 18: 1329–1343, 1997 相似文献
8.
Kazuhiko Hashimoto Takashi Oi Jun Yasuda Koji Hotta Masahiko Okada 《Journal of polymer science. Part A, Polymer chemistry》1997,35(9):1831-1838
The anionic ring-opening polymerization of 3-methyl-2-azetidinone ( 3 ) in a mixture of N,N-dimethylacetamide with lithium chloride proceeded quantitatively in a homogeneous phase at 25°C, as well as the living anionic polymerization of 3,3-dimethyl-, 4,4-dimethyl-2-azetidinone ( 1 and 2 respectively) in a similar condition. However, the molecular weight dispersion of the polyamide obtained from 3 was found to be higher than that obtained from 1 and 2. The aminolysis reaction of their N-benzoyllactams and N-acyllactams corresponding to their growing species with benzylamine was investigated kinetically, and one of the reasons for broadening of the molecular weight distribution of the polyamide obtained in the anionic polymerization of 3 was speculated to result from a low value of the ratio of the initiation reaction constant to the propagation one. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1831–1838, 1997 相似文献
9.
Noboyuki Miyaki Ikuyoshi Tomita Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》1997,35(10):2097-2103
A novel polymerization method of allene derivatives with nucleophiles bearing aryl halide moieties (A-B type) is described. By the polymerization of hexylallene with malonates bearing an aryl iodide part, polymers consisting both of internal and exomethylene (exo) double bonds were obtained by mean of the coupling reaction of three different components in high yields. On the other hand, a polymer obtained from phenylallene was selectively composed of internal double bonds (E and Z). By the reaction of hexylallene with a malonate bearing two aryl halide moieties (A-B2 type), a multibranched polymer was also obtained. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2097–2103, 1997 相似文献
10.
Noriyuki Kuramoto Yuichi Shishido Katsutoshi Nagai 《Journal of polymer science. Part A, Polymer chemistry》1997,35(10):1967-1972
Thermosensitive and redox-active polymers were prepared by copolymerization of N-ethyl- or N,N-diethylacrylamides with vinylferrocene (VFc). LCST (lower critical solution temperature) of the aqueous copolymer solution was decreased by increasing the ferrocene content in the copolymer. The oxidation of ferrocene led to a significant increase in LCST due to the transition from hydrophobic to hydrophilic character of the ferrocene moiety in the copolymer. The ferrocene content in the copolymer increases with increasing differences between the LCST's of the oxidation and reduction states. The transition could be made reversible by redox reaction using L -ascorbic acid as an oxidant and cerium sulfate as a reductant. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1967–1972, 1997 相似文献
11.
The gallium monohydride (GaH) molecule and its positive ion were theoretically investigated by abinitio molecular orbital
calculations with a flexible basis set including g-type functions on the Ga atom. Electron correlations among not only the valence electrons of Ga 4s4p and H 1s but also the semi-core electrons of Ga 3d were incorporated by a size-consistent scheme of the coupled pair approximation. The contribution of the 3d electron correlation was found to be considerable on spectroscopic constants of both GaH and GaH+, especially on the bond length.
Received: 25 July 1997 / Accepted: 13 November 1997 相似文献
12.
M. V. Encinas A. M. Rufs E. Norambuena C. Giannotti 《Journal of polymer science. Part A, Polymer chemistry》1997,35(15):3095-3100
The polymerization rate of methyl methacrylate photosensitized by p-nitroacetanilide in the presence of triethylamine was measured as a function of the amine and monomer concentrations. The polymerization proceeds readily in high-polarity media (acetonitrile/monomer) but is negligible in nonpolar media. The polymerization rate increases with the amine concentration up to 0.15M. Further increase in amine concentration does not change the polymerization rate. A similar behavior was observed for the photobleaching of the nitro compound. ESR studies show the formation of a nitro and an amine free radical, the latter free radical being the active species that adds to the monomer. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3095–3100, 1997 相似文献
13.
H. Le Rouzo 《International journal of quantum chemistry》1997,64(6):647-653
Cartesian Gaussian orbitals (CGO) about one center are expanded as a series of spherical harmonics around a new origin. Radial coefficients are given in analytical form. Developments of solid harmonic Gaussian orbitals (SHGO) are also obtained and used to study the convergence properties of expansions of s, p, d, and f Gaussians in terms of a single dimensionless parameter λ. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 64 : 647–653, 1997 相似文献
14.
15.
Nobuyuki Miyaki Ikuyoshi Tomita Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》1997,35(7):1211-1218
A novel palladium-catalyzed three-component polycondensation of 1,2,10,11-dodecatetraene, 4,4′-diiodobiphenyl, and nucleophiles was carried out using various carbanions and amines as a nucleophilic part. The polymerization with various sodium diethyl malonates produced polymers in high yields. Particularly, no exo-double bond was detected in the polymers prepared from sodium diethyl malonates bearing substituents directly on the carbanion center. The ratios of E- and Z- isomeric units in the polymers were dependent on the structure of the nucleophiles used. Other carbanions with appropriate electron-withdrawing groups such as sulphones and ketones can be also used as a nucleophile for the present polycondensation. Within heteronucleophiles examined, cyclic amines were suitable to produce polymers in high yields. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1211–1218, 1997 相似文献
16.
T. Schedel-Niedrig 《Analytical and bioanalytical chemistry》1998,361(6-7):680-682
Small chromium oxide particles (Cr2O3, CrO2) supported on titanium dioxide and oxidized Ag(111) single crystals were investigated by X-ray absorption spectroscopy at
the oxygen K-edge. The spectra were collected in the electron yield mode in order to increase the surface sensitivity. The shape of the
sharp split White line (WL) in the O K-edges spectra depended strongly on the oxidation state of the chromium ions in the probed samples suggesting that the WL
can be used as an indicator of different environments in the supported chromium oxide films. On the other hand, the O K-edges of the oxidized Ag(111) crystal indicated that the formation of the distinct oxygen species at the surface and in the
near-surface region was accompanied by a different silver-to-oxygen covalent interaction.
Received: 15 July 1997 / Revised: 22 December 1997 / Accepted: 29 December 1997 相似文献
17.
Britt Friis-Jensen Sten Rettrup C. R. Sarma 《International journal of quantum chemistry》1997,64(4):421-426
The classes of the symmetric group 𝒮N are identified by partitions of N. In this work an indexing scheme is presented which provides a dense enumeration of the classes of 𝒮N. The method is based on a graphical representation of partitions of N, which also enables the determination of the class corresponding to a given number. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 64 : 421–426, 1997 相似文献
18.
S. Sumi Mitra K. Sreekumar 《Journal of polymer science. Part A, Polymer chemistry》1997,35(8):1413-1421
Poly[N-(2-aminoethyl)acrylamido]triethylammonium dichloroiodate, tetrachloroiodate, and dibromoiodate polyhalides were developed as a new class of solid phase organic reagents. N,N′-methylenebisacrylamide crosslinked polyacrylamide support was utilized to prepare the reagents. The utility of polyhalide reagents for the α-halogenation of carbonyl compounds and oxidation of alcohols at various reaction conditions is described. The reactivity of the polyhalide reagents increased considerably in polar solvents and the optimum temperature for conducting the reactions was 30°C. Studies on halogenation and oxidation reactions using differently crosslinked polyacrylamide-based polyhalide reagents revealed that the reactivity increased up to 10% crosslinking and decreased progressively on further increase in the degree of crosslinking. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1413–1421, 1997 相似文献
19.
J. L. Trompette E. Fabrgue G. Cassanas 《Journal of Polymer Science.Polymer Physics》1997,35(15):2535-2541
The rheological behavior of two hydrogels, poly(sodium acrylate) and polyacrylamide gels, synthesized in the presence of the same crosslinking agent molecule, N,N′-methylene bis-acrylamide, has been investigated. The variation of the norm of the complex shear modulus |G*| vs. the monomer concentration (sodium acrylate or acrylamide) exhibited a different power law, depending on the nature of the monomer molecule. This discrepancy was ascribed to the influence of the properties of the monomer molecules on the crosslinked structure of the gelified networks. The analysis of the experimental results have allowed the suggestion that the elasticity exponent value was dependent on the length and on the conformation of the polymer chains connecting the junctions points of the network. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35 : 2535–2541, 1997 相似文献
20.
We present a systematic study on the reliability of different theoretical methods to represent the molecular electrostatic
potential (MEP), and MEP-derived properties of prototypical compounds containing phosphorus, sulfur and chlorine. Calculations
at the Hartree-Fock and M?ller-Plesset up to fourth-order level of theory, as well as local, non-local and hybrid density
functional computations were performed for a representative set of neutral molecules. The study was carried out using different
basis sets ranging from the medium-sized 6-31G(d ) to the large 6-31G(2d,2p) basis set, but in some test calculations more extended basis sets were also considered. The analysis of the results was
performed discussing separately the effect of the basis set and of the level of theory used to determine the molecular wavefunction
on the reliability of the MEP and MEP-derived properties.
Received: 4 March 1997 / Accepted: 27 June 1997 相似文献