Materials Literature
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Through layer-by-layer method [tetrakis(N-methylpyridyl)porphyrinato] cobalt (CoTMPyP) and polyoxometalyte were alternately deposited on 4-aminobenzoic acid (4-ABA) modified glassy carbon electrode. The resulting organic-inorganic hybrid films were characterized by cyclic voltammetry (CV), UV/visible absorption spectr…
Different organophilic layered silicates and a modified hydrotalcite were used as functional nanofillers for thermoplastic and thermosetting polymers. Polyamide 6 (PA6) and poly(butylene terephthalate) silicate nanocomposites were prepared by melt compounding using a twin-screw extruder. The morphology of the material…
Abstract The effects of ozone (O 3 ) gas exposure at various concentrations and treatment times on structural, mechanical and barrier properties of polyethylene and polyamide films were investigated. Changes in the structure of the films were monitored using an FT‐IR spectrometer. The results showed that O 3 treatment…
It is shown that, by using conventional VLSI design rules and device processing, a variety of two terminal and multiterminal integrated silicon light-emitting devices (Si-LEDs) can be routinely fabricated without any adaptation to the process, enabling the production of all-silicon monolithic optoelectronic systems. T…
The structure of the thermotropic cubic phases of 4′- n -alkoxy-3′-nitrobiphenyl-4-carboxylic acids (ANBC- n , where n indicates the number of carbon atoms in the alkoxy group) was studied by X-ray diffraction. For the homologues with n = 15, 16, 17, and 18, the cubic phase was of an Ia 3 d type, whereas the homologue…
Low voltage x-ray microanalysis, defined as being performed with an incident beam energy ≤5 keV, can achieve spatial resolution, laterally and in depth, of 100 nm or less, depending on the exact selection of beam energy and the composition of the target. The shallow depth of beam penetration, with the consequent short…
There has been some speculation that the C-6 position in UMP may be unusually acidic, stabilizing a carbanion that is generated at this position during OMP decarboxylation. On the basis of the rate of OH- catalyzed deuterium exchange at elevated temperatures we estimate that the pKa value for ionization at C-6 of dime…
The optical dephasing, caused by a quadratic interaction with acoustic phonons, is studied on the basis of the nonperturbative theory. The effect of a strong weakening of the elastic springs on the electronic transition is studied. It is found that, if the weakening brings the system close to the dynamical instability…
Chalcogenide glasses such as As 2 S 3 show prominent fluidity under intense subgap illumination. The feature is summarized, and the mechanism is discussed.
Proper material characterization of woven fabric reinforcement is important for accurate modeling of thermoforming. Thermoforming of commingled thermoplastic/glass fabric relies strictly on material deformation at temperatures above the matrix melting temperature. As the temperature increases, the viscosity decreases…
A coupled magnetomechanical model for the design and control of Villarieffect magnetostrictive sensors is presented. The model quantifies the magnetization changes that a magnetostrictive material undergoes when subjected to a dc excitation field and variable stresses. The magnetic behavior is characterized by conside…
Interference lithography with multiple beams provides two-dimensional periodic patterns in a single exposure step. It is possible to obtain various symmetries and shapes such as sparse hole arrays or dots on a hexagonal grid. However, when the number of interfering beams exceeds three, the intensity pattern depends st…
OBJECT: Mitoxantrone is a drug with potent in vitro activity against malignant brain tumor cell lines; however, its effectiveness as a systemic agent has been hampered by poor central nervous system penetration and dose-limiting myelosuppression. To avoid these problems, we incorporated mitoxantrone into biodegradable…
Abstract A new series of thermo-sensitive polyethers were prepared by anionic ring-opening polymerization of glycidyl ether derivatives: glycidyl methyl ether, ethyl glycidyl ether, and ethoxyethyl glycidyl ether. The prepared polymers have controllable molecular weight with narrow molecular weight distributions. Thes…
The combined effect of alkali and alkaline-earth ions on the redox, distribution, co-ordination and environment of Fe ions in alkali–alkaline-earth–silica glasses has been studied using a multi-technique approach. Wet chemical analysis and Mössbauer, electron spin resonance (ESR), optical absorption and photoluminesce…
Single-phase perovskite-type manganese oxides La 0.8 −x Na 0.2 □ x MnO 3+δ with x = 0.01–0.04 have been prepared by the modified sol–gel method and the influence of the vacancy concentration in the A site on their structures and magnetocaloric properties has systematically been investigated. The experimental results r…
Stishovite synthesized from natural basalt showed the highest concentration of hydrogen ever reported. The water concentration obtained from the polished single crystal of stishovite in this study was up to a maximum of 5628 ± 291 atoms of hydrogen per 10 6 silicon atoms (844 ± 44 ppm water). The concentration of hydr…
K-Ar dates of illitic clays from sedimentary rocks may contain “mixed ages,” i.e., may have ages that are intermediate between the ages of end-member events. Two phenomena that may cause mixed ages are: (1) long-lasting reaction during the burial illitization of smectite; and (2) physical mixing of detrital and diagen…
Electron-excited x-ray microanalysis performed in the variable pressure and environmental scanning electron microscopes is subject to additional artifacts beyond those encountered in the conventional scanning electron microscope. Gas scattering leads to direct contributions to the spectrum from the environmental gas,…
A highly efficient synthesis of 2-formyl-5,10,15,20-tetraarylporphyrins, 1 and 2, that can be carried out on multi-gram scales is reported. The key steps in the sequence involve use of copper(II) chelation to ensure very efficient electrophilic substitution, and the demetalation of the intermediate iminium salt that r…