Materials Literature
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The isotropic-cholesteric and cholesteric-smectic-$A$ phase transitions in cholesteryl oleyl carbonate have been studied for pressures up to 7 kbar. The latter transition possesses a tricritical point at 2.66 kbar and 60.3\ifmmode^\circ\else\textdegree\fi{}C, where the behavior changes from first to second order.
The dynamic mechanical behavior of six samples of styrene–butadiene random copolymers (SBR with 24% styrene) containing different amounts of carbon black and oil extender has been investigated in the temperature range −50° to 80°C. The measurements were carried out using a Fitzgerald apparatus working in the frequency…
Abstract Numerous small mounds are unique features of landscapes that extend from the southern part of Missouri to the coast of Texas. Many hectares of eastern Oklahoma are included in this vast area. The mounds occur in densities of 8 to 16/ha. These mounds were studied with special emphasis on the genesis, morpholog…
Clay fractions of three Andosols and a Latosol occurring in Indonesia, and two Alluvial Soils derived from pyroclastic sediments in the Philippines were examined by means of chemical analyses, X-ray diffraction, differential thermal analysis, thermogravimetry, infrared absorption spectroscopy, and electron microscopy.…
Making use of the radioisotopes of manganese, zinc and antimony, to represent radioactive corrosion products, and a radioisotope of cesium as representative fission product, the transport and deposition of these radioisotopes in a natural circulation sodium loop have been studied over a temperature range from 630°C do…
Wetting behavior of molten Na 2 O‐Fe 2 O 3 ‐SiO 2 and Na 2 O‐FeO‐SiO 2 glasses on very‐low‐carbon steel at 900°C in purified Ar was studied. The steel surface was dry‐polished and cleaned by ion bombardment. Glass frit was then placed on the metal, and the system was introduced into the furnace without exposure to air…
Results of lattice-dynamical calculations are presented which support the view that the ferroelectric phase transition in gadolinium molybdate (GMO) arises from the softening and ultimate instability of a doubly degenerate zone-edge mode of the high-temperature paraelectric phase. We have used a rigid-ion model in whi…
Mössbauer spectroscopy of iron (II)(N, N′-Dicyclohexylthiourea)6 (ClO4)2 shows the existence of two isomers. At low temperatures (T < 200°K) a form A with quadrupole splitting ΔE = 3.31 mm/sec is stable. At and above room temperature a form B with ΔE = 1.32 mm/sec is stable. For 200 °K < T < 300°K…
Several hysteresis loop models are evaluated including the well-known arctangent and hyperbolic tangent models. Other models are derived from the normal statistical distribution. A general method of deriving hysteresis loop models is shown. When the different models are compared, it is seen that the hysteresis loops a…
Summary Urea, a new mineral identical with the artificial compound, occurs as crystals associated with phosphammite, ammonian aphthitalite, and weddellite in guano from Toppin Hill, 123° 56′ E., 28° 42′ S., Western Australia. The urea occurs as elongated tetragonal pyramids, space group , a 5·646, c 4·701 Å, X-ray pow…
In metallic rare-earth compounds the exchange interaction between the $4f$ shell and the conduction electrons causes a portion of the conduction-electron magnetization to be added to the magnetization of each rare-earth atom. Because these two magnetization components will, in general, have different gyromagnetic rati…
The six platinum metals occur naturally in close association and strong chemical similarities were evident long before Mendeleev published his Periodic Table. In 1860 Claus announced his view that the platinum metals formed ‘an isolated metallic group, inseparable and solidly constituted’. The physical and metallurgic…
Using a minimal basis set of atomic orbitals the diatomic systems F 2 , F 2 + and F 2 - have been examined by means of complete configuration interaction (CI) calculations whereas, for NF, NF - and F 2 ++ , a complete valence CI treatment was employed. Potential energy curves were determined with the object of calcula…
Core gaps are used in the magnetic shunt paths of current-limiting transformers to limit secondary current under short-circuit conditions. It is shown here that for short-circuit current limited to twice normal a current limiting transformer has only 55% of the rating of a noncurrent-limiting transformer of the same p…
An enzyme activity of Bacillus subtilis has been found that catalyzes the dephosphorylation and deamination of phosphohomoserine to alpha-ketobutyrate, resulting in a bypass of threonine in isoleucine biosynthesis. In crude extracts of a strain deficient in the biosynthetic isoleucine-inhibitable threonine dehydratase…
Triphenylmethylcellulose (trityl cellulose) in which substitution of only the primary hydroxyls at C-6 on the cellulose chain occurs has been prepared using superdry cellulose derived from gel cellophane. The diacetate and dicarbanilate derivatives substituted exclusively at C-2 and C-3 secondary hydroxyls could then…
The possibility of jamming in various types of weft knitted structures is examined. Results for jamming in plain- knitted fabrics are based on a theoretical analysis of the plain structure which has been published previously by the present authors. Also, consideration of the equilibrium force systems in 1 X 1 rib and…
The various metal stearate-catalyzed thermal oxidations of 2,6,10,14,-tetramethylpentadecane (TMPD, a model compound of polypropylene) and the decomposition of TMPD hydroperoxide (TMPD-HPO) were carried out. The results obtained were compared with those of the oxidation of polypropylene reported previously;18 and the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBinding of methylmercury chloride to the model peptide, N-acetyl-L-cysteine. Proton magnetic resonance studyPaul G. Sumpson, Ted E. Hopkins, and Rizwanul HaqueCite this: J. Phys. Chem. 1973, 77, 19, 2282–2285Publication Date (Print):September 1, 1973Publication History Publi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolvent and cation dependence of the tetrahydroborate, BH4-, Raman spectrumA. E. Shirk and D. F. ShriverCite this: J. Am. Chem. Soc. 1973, 95, 18, 5901–5904Publication Date (Print):September 1, 1973Publication History Published online1 May 2002Published inissue 1 September 1…