Materials Literature
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Abstract The influences of doping the core of TiO 2 pigments with Al 2 O 3 and of various inorganic surface modifications on the rate of poly(vinyl chloride) (PVC) weathering are investigated. The kinetics of loss of gloss are transformed into photooxidation rates by using Weibull statistics of failure, and a scheme o…
Aggregation of methylcellulose in aqueous dilute solution is studied by light and small angle neutron scattering. For temperature T<293.15K, the free chains adopt a swollen conformation. For T>313.15K, a slow aggregation kinetics occurs. At qR g <1, the association number is found to vary as R g 3 . However a…
Results are presented of a complex study of the magnetic and resistive properties, the Hall effect, the thermal emf, and the longitudinal Nernst-Ettingshausen effect of an La 0.8 Ba 0.2 MnO 3 single crystal at temperatures between 77 and 400 K. A maximum was observed near the Curie temperature T c on the temperature d…
The effect of hydrogen bonding on the photochemical cis-trans isomerization is discussed on the basis of the results of absorption and fluorescence spectra as well as of the determination for the efficiencies of photochemical and photophysical processes.
The phase equilibria of the La 2 O 3 –SrO–CaO–Mn 3 O 4 system in air at 1200°C has been studied. Under these conditions, eight univariant four‐phase equilbria were observed. Quaternary phases, as well as liquid phases, were not observed. Perovskite‐structure phases LaMnO 3 , SrMnO 3 , and CaMnO 3 did not form complete…
Dielectric barrier discharge at atmospheric pressure has been applied to prepare diamond-like hydrogenated amorphous carbon films on glass and silicon substrates from CH 4 –H 2 mixtures. The coating with Knoop hardness up to 10 GPa can be deposited under CH 4 -to-H 2 ratio of 1:2 and substrate temperature of 300°C. Th…
The crystal structures of the Tutton salts (NH4)2[Cu(H2O)6](SO4)2, diammonium hexaaquacopper disulfate, formed with normal water and isotopically substituted H2(18)O, have been determined by X-ray diffraction at 9.5 K and are very similar, with Cu-O(7) the longest of the Cu-O bonds of the Jahn-Teller distorted octahed…
A sample of the natural type IIa diamond was pre-irradiated in a nuclear reactor and then annealed under isothermal conditions at 550°C. The experimental data were used to calculate a decrease in concentration of the neutral vacancy defect called GR1, corresponding to a phononless band (PLB) at 741 nm, and an increase…
The effects of substituting chromium for iron and the use of low cost ferrochromium alloys in the production of β-Ti–Fe–Cr alloys have been studied with respect to phase constitution, stability, and mechanical properties, in solution treated and quenched states using resistivity, hardness measurement, X-ray diffractio…
Several methodologies to produce α-terpinyl chloride from “hydrochlorination” of limonene were studied and the best results were obtained by reaction with 0.5 mol equiv. SOCl2 in SiO2 / CH2Cl2. Using this methodology (R)- and (S)-α-terpinyl chloride can easily be prepared in good yields from (R)- and (S)-limonene, res…
Abstract Selective-dissolution techniques by ammonium oxalate (OX), dithionite-citrate-bicarbonate (DCB), and dithionite-ethylenediaminetetraacetic acid (D-EDTA), and X-ray diffraction and Mössbauer spectroscopy were used to identify and characterize iron oxides and oxyhydroxides in the <2-mm, <50-μm, and <2-…
Systematic fatigue experiments, including both high‐cycle axial fatigue ( S – N curves) and fatigue crack growth (FCG, d a /d N –Δ K curves), were performed on a precipitation‐hardening martensitic stainless steel in laboratory air and 3.5 wt% NaCl solution. Specimens were prepared in three tempers, i.e. solution‐anne…
Micrometer sized multi-hollow spheres of epoxy resin were prepared by a physical method so-called phase inversion emulsification technique. The formation mechanism of the titled spheres was studied by incomplete phase inversion. The requisite for the formation of multi-hollow spheres was that irreversible coalescence…
The appearance of dry bands on polluted insulator surfaces may cause the ignition of electrical arcs, which in turn give rise to tracking and erosion, or may elongate until they bridge the electrodes causing flashover. Efficient models able to predict the occurrence of such a severe problem are of paramount importance…
A new steroidal alkaloid, 12-O-nicotinoylsarcostin, gagamine (1), was isolated from the roots of Cynanchum caudatum Max. (Asclepiadaceae), together with a known alkaloid, gagaminine (2). Their structures were established using spectroscopic methods, some 13C-NMR data of 2 have to be revised.
Intravenous fluids in polyvinyl chloride (PVC) packaging are known to be acidic. We proposed to determine the effect of PVC packaging on the pH of 0.9% saline solutions by comparing the predicted and measured pH of 0.9% saline equilibrated with atmospheric carbon dioxide and the measured pH of commercial solutions of…
The WO 3- x –0.1TiO 2- y thin films prepared by the sol–gel route exhibit increased lifetime and stability. A sol–gel solution mixed with nanoscopic silicon oxide particles (40 nm, 200 nm) was spin-coated onto an indium tin oxide (ITO)-covered glass substrate followed by further surface development by chemical etching…
Fatty-acid biosynthesis by a branched-chain alpha-keto acid dehydrogenase (bkd) mutant of Streptomyces avermitilis was analyzed. This mutant is unable to produce the appropriate precursors of branched-chain fatty acid (BCFA) biosynthesis, but unlike the comparable Bacillus subtilis mutant, was shown not to have an obl…
The 18-π electron ring in the phthalocyanines and porphyrins largely controls their chemical and spectroscopic properties. It is the aim of this microsymposium to explore the formation and reactivities and the spectroscopic and theoretical properties of the ring-oxidized and ring-reduced phthalocyanines and porphyrins…
Analytical expressions for the absolute change of the primary reflection intensity due to multiple diffraction are given in the kinematical approach. It is shown that satisfactory agreement between experiment and theory can be obtained for a mosaic crystal (diamond) as well as for a perfect crystal (silicon) even in t…