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921.
Jiunn-Der?LiaoEmail author Chonyu?Chen Yi-Te?Wu Chih-Chiang?Weng 《Plasma Chemistry and Plasma Processing》2005,25(3):255-273
High density and well surface-distributed oxygen microwave plasma with an extensible antenna-coupling design was utilized to modify a densely weaved and large-surface-area Nylon-6 fabric within a short treatment time. Plasma pretreatment and subsequent acrylic acid (AAc) or 2-hydroxyethyl methacrylate (HEMA) grafting process were studied and optimized at the stage after dyed and finished procedure. The monomer-grafted dyed Nylon-6 fabrics evolved lasting hydrophilic properties and thereafter created or improved surface properties such as water diffusion, drainage, moisture regain and water absorbency, in different degrees. The pHEMA-grafted sample exhibited minor effect in color perception, which was also much hydrophilic than the pAAc-grafted one. Based upon surface analyses and wetting assessment, the penetration of HEMA monomer into the plasma-treated fabric matrix contributed to the facilitation of wetting properties. This work accordingly ensures such plasma-induced system to incorporate with the pattern of hydrophilic properties on the analogous textiles without interrupting their finishing process. 相似文献
922.
Herbert C. Brown Uday S. Racherla Shankar M. Singh Richard B. Wetherill 《Tetrahedron letters》1984,25(23):2411-2414
A wide variety of α,β-acetylenic ketones were synthesized in very high yields via an exceptionally facile intermolecular reaction of lithium alkynyltrifluoroborates and carboxylic acid anhydrides. 相似文献
923.
Difficulties in carrying out the free-radical addition of trialkylsilanes (as opposed to trichlorosilane) to alkene CC bonds are partly due to telomerization competing with the radical transfer step. This can be overcome by the use of a large excess of trialkylsilane, when good yields of adduct are obtained from mono-substituted and 1,2-disubstituted alkenes. 相似文献
924.
On the modelling of solid state reactions.Synthesis of YAG 总被引:2,自引:0,他引:2
Feliksas?Ivanauskas Aivaras?Kareiva Bogdanas?LapcunEmail author 《Journal of mathematical chemistry》2005,37(4):365-376
There is a model of yttrium aluminium garnet (YAG) synthesis presented in this article. The developed model is based on nonlinear reaction–diffusion partial differential equations. The solution was carried out numerically using finite difference techniques. We got dependability curves for diffusion and reaction rates and offered possible method to localize values of diffusion and reaction rate constants precisely enough.AMS subject classification: 35K57, 65M06 相似文献
925.
Subhendu?Biswas Kamala?Mitra Bibhutosh?AdhikaryEmail author C.?Robert.?Lucas 《Transition Metal Chemistry》2005,30(5):586-592
Synthesis of six hydroxo-bridged binuclear manganese(III) complexes of formulae [MnL-X-MnL](ClO4) [X = OH (1–6)] along with a mononuclear manganese(III) complex (7) [Mn(L)(L′)(MeOH)2] [HL′ = 2-(2-hydroxy-phen-yl)benzimidazole] and two carboxylate-bridged binuclear manganese(III) complexes (8) and (9) are described. The complexes have been characterized by the combination of i.r., u.v.-vis spectroscopy, magnetic moments and by their redox properties. The electronic spectra of all the complexes exhibit almost identical features consisting of two d–d bands at ca. 550 and 600 nm, one MLCT band at ca.400 nm, together with two π–π* intra-ligand transitions at ca. 250 nm and ca.300 nm. Room temperature magnetic data range from μ = 2.7–3.0 BM indicates some super-exchange between the binuclear metal centers via bridging hydroxo/carboxylato groups. The X-ray crystal structure of the binuclear complex (5) revealed that it has a symmetric MnIIIN2O2 core bridged by a hydroxyl group. The X-ray analysis of the mononuclear complex (7) showed that the manganese-center possesses a distorted octahedral geometry. Electrochemical properties of hydroxo-bridged manganese(III) complexes (1–6) show identical features consisting of an irreversible and a quasi-reversible reduction corresponding to the Mn2III → MnIIMnIII → MnIIMnII couples in the voltammogram. It was found that electron withdrawing substituents on the ligand result in easier reduction. Complex (7) displays an irreversible reduction at 0.08 V and a reversible oxidation at 0.45V assignable to the MnIII → MnII reduction and MnIII → MnIV oxidation, respectively. The carboxylate-bridged compound (8) exhibits two irreversible oxidations at 0.4 and 0.6 V, probably due to Mn2III → MnIIIMnIV → MnIVMnIV oxidations and shows a quasi-reversible reductive wave at −0.85 V, tentatively assigned to Mn2III → MnIIMnIII reduction. 相似文献
926.
[reaction: see text] Stereoselective aminohydroxylation and dihydroxylation using osmium(VIII) oxidants enabled the short and efficient synthesis of the aminocyclitol core of hygromycin A. In addition to allowing the selective introduction of the heteroatoms N and O, the use of osmium (via an osmate ester) as a protecting group for a 1,2-glycol is also reported. This tactic allowed efficient differentiation of otherwise equivalent hydroxyl groups and allowed us to complete the synthesis in short order (14 steps) and excellent overall yield (12%). 相似文献
927.
Suyao?Xiao Xuanming?LiuEmail author Chunyi?Tong Jun?Liu Dongying?Tang Lijian?Zhao 《中国科学B辑(英文版)》2005,48(2):162-166
Anion starch nanoparticle (StNP) with a diameter of 50 nm was prepared in water-in-oil microemulsion, with soluble starch
as raw materials and POCl3 as crosslinking agent. PLL-StNP was prepared by linking poly-L-lysine (PLL) on the surface of StNP. At the same time, the
size of PLL-StNP and its stability in aqueous solution were checked by AFM. The analysis of plasmid DNA binding, DNase I enzymatic
degradation, toxicity and transfection were done. We discovered that PLL-StNP may be used as non-virus nanoparticle gene carrier.
And we developed the method of preparing PLL-StNP gene carrier and used it in cell transfection. As non-virus gene carrier,
PLL-StNP has some advantages, such as large load of DNA, high transfection efficiency, low cell toxicity and biodegradability. 相似文献
928.
Multicomponent Ni-base alloys exhibit good mechanical properties even at elevated temperatures and they are widely used for
industrial production of exertion-resistive parts of engines. These properties are mainly determined by the coexistence of
a disordered γ matrix with a face centred cubic lattice and cuboidal domains of its ordered γ′ structure. Therefore it is
useful to study phase equilibria in Ni-base systems, namely in the regions involving both mentioned phases. One of the conclusions
of our recent work on Ni–Al–Cr–W system was a necessity of modification of selected thermodynamic parameters of the ternary
Ni–Al–W subsystem in order to achieve a better agreement of our experimental observations with theoretical modelling. This
involves new measurements of the microstructure of selected samples of the Ni–Al–W system at 900°C and the comparison of the
results with existing literature data in order to confirm our conclusions on higher order system investigated before. It is
a first step on the way to an assessment of the Ni–Al–W system, which has not been done before. 相似文献
929.
Kean H. Khoo K. Rodney Fernando Richard J. Fereday Chee-Yan Chan 《Journal of solution chemistry》1995,24(10):1039-1048
The solubility of thallium(I) chloride has been determined in aqueous solutions of strontium chloride and barium chloride at concentrations up to 1.5 mol kg–1. The data were analyzed using Pitzer's equations without making explicit assumption of association to ion pairs by assuming =3 instead of =2, with the (1) term for TlCl being equivalent to the (2) term for 2-2 electrolytes. Best values of (0) and (1) for TlCl are recommended together with K
s
, the activity solubility product. These were used to fit the present solubility data and derive the Pitzer model mixture parameters relevant to the systems, fTIN and fTINCl (N=Sr, Ba). Mixture parameters for TlCl+MCl+H2O systems are also derived to complete the parameter base. The fit of the experimental data was found to be worse when higher-order terms for asymmetrical mixing were included in the analysis. Activity coefficients for thallium(I) chloride in the mixtures are derived. 相似文献
930.
Yoshim Tokura Richard L. Edelson Francis P. Gasparro 《Photochemistry and photobiology》1993,58(6):822-826
Abstract The effects of cell differentiation and mitogen and phorbol ester stimulation on the formation of 8-methoxypsoralen (8-MOP)-DNA photoadducts in murine T lymphocytes were examined using 3 H-8-MOP. While there were no significant differences in 8-MOP photoadduct formation among BALB/c thymocytes, splenocytes, splenic T cells and MRL/1pr lymph node cells, BALB/c bone marrow cells showed fewer photoadducts than did the lymphocytes. This suggested that proliferating progenitor cells may be resistant to 8-MOP photoadduct formation. Incubation of purified splenic T cells with lectin mitogens for 2 h or with phorbol 12-myristate 13-acetate (PMA) for 2–43 h resulted in reduction of 8-MOP photoadduct formation in the DNA, whereas 64 h cultivation with these agents augmented the photoadduct formation. The reduction of photoadduct formation induced by phytohemagglutinin was restored by the further addition of a protein kinase C (PKC) inhibitor, H-7, to the culture. Thus, it is assumed that the reduction of adduct formation evoked by mitogens and PMA is mediated in part by the activation of PKC in the cells. On the other hand, the augmentation of the adduct formation induced by the longer-period cultures with mitogens and PMA appeared to be caused by down-regulation of PKC. The present study showed that the stimulatory signals in which PKC is presumably involved affect the ability of cells to form 8-MOP-DNA photoadducts. 相似文献