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1.
Mechanical and physico-chemical characterization of cyclodextrin finished polyamide fibers 总被引:2,自引:0,他引:2
Yassine El Ghoul Bernard Martel Michel Morcellet Christine Campagne Ahmida El Achari Sadok Roudesli 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):47-52
We present the study of the cyclodextrin (CDs) finishing of polyamide fibers (PA) by means of citric acid (CTR) as crosslinking agent. We observed that the mode of grafting happened by the formation of a crosslinked polymer formed between CTR and CDs. This polymer physically adhered to the fibers network and was resistant to hot water washings. Modified fibers were characterized by evaluating the contact angle with a polar liquid and by studying the hysteresis of damping of PA fibers (Cahn balance) with various grafting rates and by studying the absorptivity of grafted fabrics via the technique of the posed drop (Digidrop® instrument). Then a mechanical characterization of the PA fabrics grafted with various proportions of CDs was accomplished, by traction and tear tests by using a tensile-test bench Lohmergy. Finally a topographic study of PA grafted surfaces was approached by atomic force microscopy (AFM and LFM; contact and non-contact mode) which permitted to evaluate the roughness and the chemical heterogeneity of the grafted surfaces. 相似文献
2.
A novel gas diffusion-flow injection method has been developed for the rapid and sensitive determination of total inorganic carbon (TIC) in water. The method is based on the diffusion of CO2 across gas permeable membrane from a donor stream containing 0.1 M HCl to an acceptor stream of sodium acetate (10−5 mol l−1 and pH 10). The CO2 trapped in the acceptor stream passes through an electrochemical flow cell contains a tungsten oxide wire and a silver/silver chloride electrode, where it was sensitively detected. The parameters affecting the sensitivity of the electrode such as buffer concentration, pH, flow rate and injected volume were studied in detail. The electrode response was linear in the concentration range from 5 to 100 μg ml−1 CO32− with a correlation coefficient (R2) of 0.998. Precision (R.S.D.) was 1.42% for 20 μg ml−1 standard solution of CO32− (n=10). The detection limit was 0.20 μg ml−1 CO32−. The method was evaluated by the injection of real natural water samples and an average recovery of 100.1% was obtained. The sampling rate was 30 samples h−1. The method is simple, feasible with satisfactory accuracy and precision and thus could be used for monitoring TIC in water. 相似文献
3.
We relate the brace products of a fibration with section tothe differentials in its Serre spectral sequence. In the particularcase of free loop fibrations, we establish a link between thesedifferentials and Browder operations in the fiber. Applicationsand several calculations (for the particular cases of spheresand wedges of spheres) are given. 2000 Mathematical SubjectClassification: 55P35, 55Q15, 55R05, 55R20. 相似文献
4.
The truncated singular value decomposition is a popular method for the solution of linear ill-posed problems. The method requires the choice of a truncation index, which affects the quality of the computed approximate solution. This paper proposes that an L-curve, which is determined by how well the given data (right-hand side) can be approximated by a linear combination of the first (few) left singular vectors (or functions), be used as an aid for determining the truncation index. 相似文献
5.
We discuss the design and implementation of a vector extrapolation method for computing numerical solutions of the steady-state Navier-Stokes equation system. We describe a “proof of concept” implementation of vector extrapolation, and we illustrate its effectiveness when integrated into the Incompressible Flow Iterative Solution Software (IFISS) package ( http://www.manchester.ac.uk/ifiss). 相似文献
6.
Nanohybrid materials resulting from the intercalation of ionic liquids or from the grafting of aminoalcohols into the interlayer
space of kaolinite pre-intercalated with dimethyl sulfoxide (DMSO), were successfully synthesized. Thermal analysis (TG and
DTA) data, coupled with X-ray diffraction (XRD) data, and 13C MAS-NMR spectroscopic analysis, as well as with hydrolysis reactions, were used for qualitative and quantitative characterisations.
In the case of intercalated nanohybrid materials obtained by insertion of ionic liquids and of ethanolamine into the interlayer
spaces of kaolinite upon displacement of DMSO, no major changes in the dehydroxylation temperature of the layer sheets could
be observed. The stoichiometry of the intercalated organo-kaolinite materials was obtained from several independent measurements
(TG, CHN) and theoretical calculation (THM). They were in good agreement. Grafted nanohybrid materials resulting from the
formation of a covalent bond between the hydroxyl groups of diethanolamine and triethanolamine and the internal surfaces aluminol
groups of kaolinite exhibited a significantly lower dehydroxylation temperature. A combined approach of hydrolysis reactions
and TG analysis allows an unambiguous distinction between grafted and intercalated organo-kaolinite nanohybrid materials. 相似文献
7.
Two difference schemes are derived for numerically solving the one-dimensional time distributed-order fractional wave equations. It is proved that the schemes are unconditionally stable and convergent in the \(L^{\infty }\) norm with the convergence orders O(τ 2 + h 2+Δγ 2) and O(τ 2 + h 4+Δγ 4), respectively, where τ,h, and Δγ are the step sizes in time, space, and distributed order. A numerical example is implemented to confirm the theoretical results. 相似文献
8.
Sébastien Duminil Mohammed Heyouni Philippe Marion Hassane Sadok 《Numerical Algorithms》2016,71(2):383-394
The CMRH (Changing Minimal Residual method based on the Hessenberg process) method is a Krylov subspace method for solving large linear systems with non-symmetric coefficient matrices. CMRH generates a (non orthogonal) basis of the Krylov subspace through the Hessenberg process, and minimizes a quasi-residual norm. On dense matrices, the CMRH method is less expensive and requires less storage than other Krylov methods. In this work, we describe Matlab codes for the best of these implementations. Fortran codes for sequential and parallel implementations are also presented. 相似文献
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10.
Range restricted iterative methods based on the Arnoldi process are attractive for the solution of large nonsymmetric linear
discrete ill-posed problems with error-contaminated data (right-hand side). Several derivations of this type of iterative
methods are compared in Neuman et al. (Linear Algebra Appl. in press). We describe MATLAB codes for the best of these implementations.
MATLAB codes for range restricted iterative methods for symmetric linear discrete ill-posed problems are also presented. 相似文献