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101.
Toshiki Kono Toshikazo Sakaguchi Yanming Hu Masashi Shiotsuki Fumio Sanda Toshio Masuda 《Journal of polymer science. Part A, Polymer chemistry》2006,44(20):5943-5953
Phenylacetylene (PA) derivatives having two polar groups (ester, 2a – d ; amide, 4) or one cyclic polar group (imide, 5a – c ) were polymerized using (nbd)Rh+[(η6‐C6H5)B?(C6H5)3] catalyst to afford high molecular weight polymers (~1 × 106 – 4 × 106). The hydrolysis of ester‐containing poly(PA), poly( 2a) , provided poly(3,4‐dicarboxyPA) [poly ( 3 )], which could not be obtained directly by the polymerization of the corresponding monomer. The solubility properties of the present polymers were different from those of poly(PA) having no polar group; that is, poly( 2a )–poly( 2d ) dissolved in ethyl acetate and poly( 4 ) dissolved in N,N‐dimethylformamide, while poly(PA) was insoluble in such solvents. Ester‐group‐containing polymers [poly( 2a )–poly( 2d )] afforded free‐standing membranes by casting from THF solutions. The membrane of poly( 2a ) showed high carbon dioxide permselectivity against nitrogen (PCO2/PN2 = 62). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5943–5953, 2006 相似文献
102.
Makoto Kato Azusa Tsukigase Hiromitsu Tanaka Arimitsu Usuki Isamu Inai 《Journal of polymer science. Part A, Polymer chemistry》2006,44(3):1182-1188
Isobutylene isoprene rubber (IIR)‐clay nanocomposites have been prepared successfully by melt intercalation with maleic anhydride‐grafted IIR (Ma‐g‐IIR) and organophilic clay. In IIR‐clay nanocomposites, the silicate layers of the clay were exfoliated and dispersed into the monolayer. The nanocomposites exhibited greater gas barrier properties compared with those of Ma‐g‐IIR. When 15 phr clay was added, gas barrier properties were 2.5 times greater than those of Ma‐g‐IIR. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1182–1188, 2006 相似文献
103.
Tungsten trioxide and titanium dioxide thin films were synthesised by pulsed laser deposition. We used for irradiations of oxide targets an UV KrF* (λ = 248 nm, τFWHM ≅ 20 ns, ν = 2 Hz) excimer laser source, at 2 J/cm2 incident fluence value. The experiments were performed in low oxygen pressure. The (0 0 1) SiO2 substrates were heated during the thin film deposition process at temperature values within the 300-500 °C range. The structure and crystalline status of the obtained oxide thin films were investigated by high resolution transmission electron microscopy. Our analyses show that the films are composed by nanoparticles with average diameters from a few to a few tens of nm. Moreover, the films deposited at substrate temperatures higher than 300 °C are crystalline. The tungsten trioxide films consist of a mixture of triclinic and monoclinic phases, while the titanium dioxide films structure corresponds to the tetragonal anatase phase. The oxide films average transmittance in the visible-infrared spectral range is higher than 80%, which makes them suitable for sensor applications. 相似文献
104.
Ternary Ti-Si-N refractory barrier films of 15 nm thick was prepared by low frequency, high density, inductively coupled plasma implantation of N into TixSiy substrate. This leads to the formation of Ti-N and Si-N compounds in the ternary film. Diffusion of copper in the barrier layer after annealing treatment at various temperatures was investigated using time-of-flight secondary ion mass spectrometer (ToF-SIMS) depth profiling, X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and sheet resistance measurement. The current study found that barrier failure did not occur until 650 °C annealing for 30 min. The failure occurs by the diffusion of copper into the Ti-Si-N film to form Cu-Ti and Cu-N compounds. FESEM surface morphology and EDX show that copper compounds were formed on the ridge areas of the Ti-Si-N film. The sheet resistance verifies the diffusion of Cu into the Ti-Si-N film; there is a sudden drop in the resistance with Cu compound formation. This finding provides a simple and effective method of monitoring Cu diffusion in TiN-based diffusion barriers. 相似文献
105.
106.
Richard A. Cairncross Jeffrey G. Becker Shri Ramaswamy Ryan O'Connor 《Applied biochemistry and biotechnology》1996,131(1-3):774-785
Management of moisture penetration and hydrolytic degradation of polylactide (PLA) is extremely important during the manufacturing,
shipping, storage, and end-use of PLA products. Moisture transport, crystallization, and degradation, in PLA have been measured
through a variety of experimental techniques including size-exclusion chromatography, differential scanning calorimetry, and
X-ray diffraction. Quartz crystal microbalance and dynamic vapor sorption experiments have also been used to measure moisture
sorption isotherms in PLA films with varying crystallinity. A surprising result is that, within the accuracy of the experiments,
crystalline and amorphous PLA films exhibit identical sorption isotherms. 相似文献
107.
We consider the two-dimensional one-component plasma without a background and confined to a half-plane near a metal wall. The particles are also subjected to an external potential acting perpendicular to the wall with an inverse-power-law Boltzmann factor. The model has a known solvable isotherm which exhibits a Kosterlitz-Thouless-type transition from a conductive to an insulator phase as the power law is varied. This allows predictions of theoretical methods of analyzing the Kosterlitz-Thouless transition to be compared with the exact solution. In particular, we calculate the asymptotic density profile by resumming its low-fugacity expansion near the zero-density critical coupling in the insulator phase, and solving a mean-field equation deduced from the first BGY equation. Agreement with the exact solution is obtained. As the former calculation makes essential use of the nested dipole hypothesis of Kosterlitz and Thouless, the validity of this hypothesis is explicitly verified. 相似文献
108.
We present some asymptotic results for the family of pausing time densities having the asymptotic (t) property(t) [t ln1+(t/T)]–1. In particular, we show that for this class of pausing time densities the mean-squared displacement r
2(t) is asymptotically proportional to ln(t/T), and the asymptotic distribution of the displacement has a negative exponential form. 相似文献
109.
We investigate the topology of the phase diagram of binary alloys on the fee lattice with first-neighbor antiferromagnetic interactions around the superdegenerate point, where the L10 and L12 phases meet. We treat the system as a hard-constraint lattice gas, following a procedure previously described by Lebowitzet al. We perform cluster variation method calculations in theT0 limit and Monte Carlo simulations directly atT=0 K on the ground states of the superdegenerate point. We find that: (i) there is no disordered phase in the neighborhood of this point; (ii) a phase L for which two of the four cubic sublattices have the same average occupancy and each of the two others are different appears between L10 and L12; (iii) the transition L/L12 is of first order. 相似文献
110.
We study a one-dimensional model for fracture, identifying fractured areas with intervals on which a stress field exceeds a threshold value. When is a diffusion process, the cumulative numberN(l) of fractured areas whose length is greater thanl obeys a power lawCl
–p
asl0 with probability one. The exponentp and the constantC are determined. The exponentp agrees with the Hausdorff dimension of the end points of fractured areas, i.e.,
–1(). Even if is self-similar with parameterH>0, i.e.,(cx)– is equivalent toc
H
{(x)–} for anyc>0, the exponentp does not depend solely onH;p=H, where(0, 1/H) is another parameter characterizing. Non-diffusion processes are given whereN(l) does not follow a power law. 相似文献