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Good Transparency (good + transparency)
Selected AbstractsPhysical properties of Dy and La doped SnO2 thin films prepared by a cost effective vapour deposition techniqueCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2006J. Joseph Abstract Stannous oxide (SnO2) thin film is one of the most widely used n-type transparent semi-conductor films in electronics, electro-optics and solar energy conversion. By achieving controlled non-stoichiometry, we can get good transparency and high electrical conductivity simultaneously in SnO2 thin films. Dy and La doped SnO2 thin films have been prepared by a cost effective vapour deposition technique. The structural, photo-electronic, optical and electrical properties of the doped and undoped films were studied. The results of X-ray Diffraction studies reveals the polycrystalline nature of the films with preferential orientation along the (101), (211) and (301) planes and their average grain size variation for different deposition temperature. Photoconductivity and Photovoltaic studies of the films were also performed. The optical properties of these films were studied by measuring their optical transmission as a function of wavelength. The optical transmission is found to be increased on Dy doping and decreased on La doping. The band gap, refractive index and thickness of the films were calculated from U-V transmittance and Absorption graphs. The optical band gap of undoped film is found to be 4.08 eV, but on doping it shifts to lower energies and then increases on increasing the concentration of both dopants. Its electrical parameters such as sheet resistance, resistivity, mobility, Hall coefficient, and carrier concentration were determined by Four Probe, Van der Pauw and Hall Probe method. On doping with Dy, carrier conversion takes place from n-type to p-type and p-conductivity dominates. On La doping no carrier conversion takes place but resistivity decreases. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Improved understanding of velocity,saturation relationships using 4D computer-tomography acoustic measurementsGEOPHYSICAL PROSPECTING, Issue 2 2005K. Monsen ABSTRACT A recently developed laboratory method allows for simultaneous imaging of fluid distribution and measurements of acoustic-wave velocities during flooding experiments. Using a specially developed acoustic sample holder that combines high pressure capacity with good transparency for X-rays, it becomes possible to investigate relationships between velocity and fluid saturation at reservoir stress levels. High-resolution 3D images can be constructed from thin slices of cross-sectional computer-tomography scans (CT scans) covering the entire rock-core volume, and from imaging the distribution of fluid at different saturation levels. The X-ray imaging clearly adds a new dimension to rock-physics measurements; it can be used in the explanation of variations in measured velocities from core-scale heterogeneities. Computer tomography gives a detailed visualization of density regimes in reservoir rocks within a core. This allows an examination of the interior of core samples, revealing inhomogeneities, porosity and fluid distribution. This mapping will not only lead to an explanation of acoustic-velocity measurements; it may also contribute to an increased understanding of the fluid-flow process and gas/liquid mixing mechanisms in rock. Immiscible and miscible flow in core plugs can be mapped simultaneously with acoustic measurements. The effects of core heterogeneity and experimentally introduced effects can be separated, to clarify the validity of measured velocity relationships. [source] Enhancing Physical Properties and Antimicrobial Activity of Konjac Glucomannan Edible Films by Incorporating Chitosan and NisinJOURNAL OF FOOD SCIENCE, Issue 3 2006Bin Li ABSTRACT: The antimicrobial effect of konjac glucomannan (KGM) edible űlm incorporating chitosan (CHI) and nisin at various ratios or concentrations was studied. This activity was tested against pathogenic bacteria, namely, Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus. Mechanical and physical properties were determined, and the results indicated that the blend film KC2 (mixing ratio KGM 80/ CHI 20) showed the maximum tensile strength (102.8 ± 3.8 MPa) and good transparency, water solubility, and water vapor transmission ratio. Differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the structural change of the blend films; and the results showed that strong intermolecular hydrogen bonds occurred between CHI and KGM. Incorporation of nisin at 463IU per disk of film for the selected KC2 was found to have antimicrobial activity against S. aureus, L. monocytogenes, and B. cereus. The mean value of inhibition zone diameter of the CHI-N series and the KC2-N series were higher than the KGM-N series at each corresponding concentration and with significant difference (P < 0.05), however, there was no significant difference in the antimicrobial effect between CHI and KC2 incorporating nisin. At all these levels, the blend űlm KC2-nisin had a satisfactory appearance, mechanical and physical properties, and antimicrobial activity. Therefore, it could be considered as a potential "active" packaging material. [source] Enhancing electrochromic properties of conducting polymers via copolymerization: Copolymer of 1-(4-fluorophenyl)-2,5-di(thiophen-2-yl)-1H -pyrrole with 3,4-ethylene dioxythiophene,JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2007Ozlem Turkarslan Abstract A copolymer of 1-(4-fluorophenyl)-2,5-di(thiophen-2-yl)-1H -pyrrole (FPTP) with 3,4-ethylene dioxythiophene (EDOT) was electrochemically synthesized and characterized. While poly(FPTP) (P(FPTP)) has only two colors in its oxidized and neutral states (blue and yellow), its copolymer with EDOT has five different colors (purple, red, light gray, green, and blue). Electrochromic devices based on P(FPTP- co -EDOT) and poly(3,4-ethylenedioxythiophene) (PEDOT) were constructed and characterized. The oxidized state of the device shows blue color whereas it shows purple for the reduced state. At several potentials the device has good transparency with green and gray colors. Maximum contrast (,%T) and switching time of the device were measured as 23% and 1.1 s at 555 nm. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4496,4503, 2007 [source] Synthesis and characterization of poly(arylene ether)s derived from 4,4,-bishydroxybiphenyl and 4,4,-bishydroxyterphenylJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2002Arun Kashinath Salunke Abstract A series of poly(arylene ether)s were successfully prepared by aromatic, nucleophilic substitution reactions with various perfluoroalkyl-activated bisfluoromonomers with 4,4,-bishydroxybiphenyl and 4,4,-bishydroxyterphenyl. 4,4,-Bishydroxyterphenyl was synthesized through the Grignard coupling reaction of magnesium salt of 4-bromoanisole with dibromobenzene followed by demethylation with pyridine,hydrochloride. The products obtained by the displacement of fluorine atoms exhibited good inherent viscosity, up to 0.77 dL/g, and number-average molecular weights up to 69,300. These poly(arylene ether)s showed very good thermal stability, up to 548 °C for 5% weight loss according to thermogravimetric analysis under synthetic air, and high glass-transition temperatures, up to 259 °C according to differential scanning calorimetry, depending on the exact repeat unit structure. These polymers were soluble in a wide range of organic solvents, such as N -methylpyrrolidone, dimethylformamide, tetrahydrofuran, toluene, and CHCl3, and were insoluble in dimethyl sulfoxide and acetone. Thin films of these poly(arylene ether)s showed good transparency and exhibited tensile strengths up to 132 MPa, moduli up to 3.34 GPa, and elongations at break up to 84%, depending on their exact repeating unit structures. These values are comparable to those of high-performance thermoplastic materials such as poly(ether ether ketone) (PEEK) and Ultem poly(ether imide) (PEI). These poly(arylene ether)s exhibited low dielectric constants. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 55,69, 2002 [source] Stress,strain behavior as related to surface topography and thickness uniformity in uni- and biaxially stretched PVDF/PMMA blendsPOLYMER ENGINEERING & SCIENCE, Issue 12 2007Xixian Zhou The influence of blend composition and processing conditions on the surface roughness and thickness uniformity of PVDF/PMMA blends were investigated in uniaxial and biaxial deformation mode for PVDV and PVDF/PMMA blends 70/30, 55/45, and 40/60 wt%. The addition of PMMA retards the thermal crystallizability of the blends and this allows rapid solidification into films with little or no crystallinities. Such precursors with lowered crystallinity were found to be easily uni- and biaxially stretched into uniform and transparent films in the temperature range between the glass transition temperature and cold crystallization temperature where they exhibit strain hardening. Thus, these blends are suitable for processes such as tenter frame biaxial stretching, double bubble film blowing, and stretch blow molding where they will exhibit good transparency and thickness uniformity. POLYM. ENG. SCI., 47:2110,2117, 2007. © 2007 Society of Plastics Engineers [source] | ||||||||||