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991.
Ren Yan-Wei Dang Li-Long Li Jun Gao Wei-wei Zhang Feng-Xing 《Journal of Structural Chemistry》2005,46(2):352-357
A novel one-dimensional (1D) chain coordination polymer [Mn2(2,2′-dipha)2(phen)]n has been synthesized by hydrothermal reaction, and characterized by elemental analysis, IR spectroscopy, TGA, and X-ray diffraction. Orange crystals crystallized in the monoclinic system, space group C2/c with a = 19.393(7) Å, b = 19.183(7) Å, c = 19.729(7) Å, β = 90.826(6)°, V = 7338(5) Å3, Z = 8. In the crystal structure, one manganese atom is six-coordinated with four carboxylate oxygen atoms from one pentadentate 2,2′-dipha ligand and two tetradentate 2,2′-dipha ligands, and with two nitrogen atoms of one phen ligand, giving a slightly distorted octahedral geometry. The other manganese atom is five-coordinated with five oxygen atoms from two tetradentate 2,2′-dipha ligands and two pentadentate 2,2′-dipha ligands and has a trigonal bipyramidal environment. The TGA curve shows that the compound is stable below 310°. 相似文献
992.
Yanbing Zhao Wanyu Chen Yajiang Yang Xiangliang Yang Huibi Xu 《Colloid and polymer science》2007,285(12):1395-1400
Ionically cross-linked polyampholytic hydrogels were synthesized by redox copolymerization of acrylamide and an ionic complex
of (N,N-diethylamino)ethyl methacrylate and acrylic acid (designated as PADA hydrogel). The swelling behavior of the hydrogels in
water indicated that a minimal equilibrium swelling ratio is found when the molar ratio of anionic/cationic monomers was 1.55.
In NaCl solution, the hydrogels exhibited the typical swelling behavior of conventional polyampholytic gels. Their equilibrium
swelling ratios increased with an increase in the NaCl concentration. In solutions of multivalent ions (CaCl2 and trisodium citrate solutions), the equilibrium swelling ratios of the hydrogels increased first and were then followed
by a decrease with an increase in salt concentration. Interestingly, an unexpected abrupt swelling phenomenon was observed
when the fully swollen hydrogels in salt solution were transmitted to pure water. The unique swelling behavior of PADA hydrogels
depends not only on the molar ratio of the anionic/cationic monomers but also on the valency of the ions. 相似文献
993.
Ladislav Halás Andrej Oriňák Abubaker Sharif Monika Ádámová Juraj Ladomerský 《Central European Journal of Chemistry》2005,3(3):570-582
Acrylate monomers methylmethacrylate (MMA) and cyclohexylmethacrylate (CHMA) bioaccumulation has been determined in aquatic
organism, algae (Chlorella kessleri). Algae were collected in amount of 0.4 mg and directly injected to the pyrolytical cell. In algae bodies accumulated monomers
were analysed by pyrolysis gas chromatography (Py-GC) and pyrolysis gas chromatography coupled with mass spectrometry (Py-GC/MS).
Traces of the accumulated monomers in algae body can be determined after 1-, 2-, 3-weeks of incubation. Maximum content of
MMA was determined after 3-week of experiment, contrariwise in the case of CHMA after 2-week exposition. Relationship with
pyrolysis temperature has also been studied. 相似文献
994.
V. L Gein E. N. Bezmaternykh L. F. Gein I. V. Krylova 《Chemistry of Heterocyclic Compounds》2004,40(10):1332-1334
It has been shown that 5-aryl-3-arylamino-4-benzoyl-1H-3-pyrrolin-2-ones cyclize in the presence of conc. H2SO4 to give pyrrolo[3,4-b]quinolines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1543–1545, October, 2004. 相似文献
995.
Schultz J Gottlieb DM Petersen M Nesic L Jacobsen S Søndergaard I 《Electrophoresis》2004,25(3):502-511
Methods for classification of two-dimensional (2-DE) electrophoresis gels based on multivariate data analysis are demonstrated. Two-dimensional gels of ten wheat varieties are analyzed and it is demonstrated how to classify the wheat varieties in two qualities and a method for initial screening of gels is presented. First, an approach is demonstrated in which no prior knowledge of the separated proteins is used. Alignment of the gels followed by a simple transformation of data makes it possible to analyze the gels in an automated explorative manner by principal component analysis, to determine if the gels should be further analyzed. A more detailed approach is done by analyzing spot volume lists by principal components analysis and partial least square regression. The use of spot volume data offers a mean to investigate the spot pattern and link the classified protein patterns to distinct spots on the gels for further investigation. The explorative approach in analysis of 2-D gels makes it possible, in a fast and convenient way, to screen many gels in order to determine the protein patterns that form clusters and could be selected for further examination. 相似文献
996.
Thanwarat Pipatchanchai Kawee Srikulkit 《Journal of Sol-Gel Science and Technology》2007,44(2):119-123
Water repellency of woven cotton fabric was achieved by coating with the aqueous dispersion containing organosilane agent
(HDTMS) and fumed silica. The coating agents were applied using padding method and then followed by batching the coated fabric
at the ambient temperature for 24 h to allow the condensation reaction between HDTMS silanol group and fumed silica silanol
group, rendering silica particles hydrophobic. An ultrasonicator was employed to prepare the homogenous coating dispersion.
The water repellency evaluated by water contact angle determination which showed the contact angle over 110° was obtained
with low amount of applied HDTMS of 1 wt%. The effect of fumed silica addition on an increase in fiber surface roughness geometry
showed the influential result in improving the water contact angle. From durability to washing test, the hydrophobic coatings
evidenced from SEM and ATR/FTIR remained adhering to fiber surface, indicating the durability. After washing, the coating
on the fabric with fumed silica addition appeared to be scatter particles which made a contribution to the higher contact
angle value when compared to sheet-like layer coating in case of HDTMS coating alone. 相似文献
997.
Comparison
of the fragility index of different eudragit polymers determined by activation
enthalpies
Gabriella Csóka A. Gelencsér Dorottya Kiss Eszter Pásztor I. Klebovich Romána Zelkó 《Journal of Thermal Analysis and Calorimetry》2007,87(2):469-473
The present study aimed to apply fragility
index (m) of polymers in the determination
of the optimal amount of plasticizer in polymer films. The fragility index
of different Eudragit polymers (RS, RL, EPO) was assessed by differential
scanning calorimerty (DSC), applying the Arrhenius connection (logq–1/T
g).
The fragility of Eudragit EPO films proved to be the highest, while in the
case of RS and RL, the increase of the alkyl-chain length caused the increase
of fragility. Studying the effect of plasticizer (triethyl citrate, TEC) on
the m value of Eudragit RL and RS films,
a near linear reduction of the fragility index could be observed between 5–30%
TEC concentration, but above 30%, this value leveled out to constant. 相似文献
998.
Mixed micelles formed by zwitterionic surfactant dimethyldodecylammniopropane sulfonate and short-chain phospholipid 1,2-diheptanoyl-sn-glycero-3-phosphocholine in different proportions in an aqueous medium have been studied physicochemically at an air/water interface and in the bulk by using interfacial tension and pyrene fluorescence intensity measurements, respectively. The critical micellar concentration and free energies of micellization and of interfacial adsorption have been determined. The interfacial study reveals that a mixed monolayer is formed at the air/water interface by the adsorption of surfactant and phospholipid monomers. This has been confirmed by evaluating the interfacial parameters; the maximum surface excess, the minimum area per molecule of a surface-active compound, and the Gibbs surface excess related to surface pressure. The nonideality of mixing, expressed in the terms of the regular solution interaction parameter, #, has negative values over the whole mole fraction range. The negative # values indicate the mutual synergism between the surfactant and phospholipid monomers. The equilibrium distribution of components between micelle and monomer phases was evaluated using a theoretical treatment based on excess thermodynamics quantities evaluated by Motomura's formulation. 相似文献
999.
Of ammonium, lithium and sodium salts of dodecyl sulfate studied as surfactants in the separation of iridoid glycosides by micellar electrokinetic capillary chromatography (MECC), the last one gave the best results. Eleven neutral iridoid glycosides were separated by MECC with sodium dodecyl sulfate as surfactant, and the water–micelle partition coefficients of the compounds were calculated. The separation system was coupled via a coaxial sheath flow electrospray interface to a mass spectrometer, and the partial filling technique was used in the on-line analysis. Seven plant species belonging to five genera (Plantago, Veronica, Melampyrum, Succisa and Valeriana) were screened for the iridoid glycosides by the new method that was developed. The findings confirmed those of an earlier study on five of the iridoid glycosides. Some new iridoid glycosides were found in Plantago lanceolata, Veronica spicata and V. chamaedrys. 相似文献
1000.
With P(CH3)3 as the probe molecule adsorbed on titanium silicalite (TS-1) zeolite, the special and important role of T12 site in MFI-type zeolite was clearly elucidated. There are altogether three active sites present in TS-1 zeolite with Ti at the T12 site. Owing to the preferential adsorption of probe molecules on the first Brönsted acidic site, the Ti12 center will probably fail to show Lewis acidity. The ionic [HP(CH3)3]+ species can be stabilized by the first or second Brönsted acidic site, with the former energetically favored. The latter was formed through the transfer of the ionic [HP(CH3)3]+ species from the first to the second Brönsted acidic site. 相似文献