Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
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…
The transmission spectrum of antiferromagnetic FeC${\mathrm{O}}_{3}$ has been investigated in the far-infrared region from 20 to 300 ${\mathrm{cm}}^{\ensuremath{-}1}$, for temperatures from 4.2 to 70 K and in applied fields up to 90 kOe. Spectra were obtained from natural single crystals and high-purity synthetic powd…
By using techniques developed by many workers to study streamer mechanism in air between metallic electrodes, the phenomena of partial discharges in insulating walls were studied. It is shown that the luminous evolution of partial discharges consisted of the development of a primary and a secondary streamer, for posit…
We have measured the fluorescent decay rates of the $^{3}P_{0}$ and $^{3}P_{1}$ states of the ${\mathrm{Pr}}^{3+}$ ion in Pr${\mathrm{Cl}}_{3}$ and La${\mathrm{Cl}}_{3}$ over a wide range of temperatures. At low temperatures the radiative lifetime of the $^{3}P_{0}$ state in La${\mathrm{Cl}}_{3}$:1-at.% Pr is 14.7 \if…
Abstract Metalation of diene polymers such as poly (butadiene) and poly(isoprene) with sec-butyllithium and tetramethylethylenediamine in cyclohexane at room temperature forms lithiated polydienes. Reaction of the polylithiodienes with styrene or α-methylstyrene forms graft copolymers. The extent of metalation is much…
Advances in diffraction grating ruling made in the past twenty-five years are reviewed, particularly demonstrating the application of interferometry and electronics to ruling engine control. Portions of this paper were presented at the Eighth Australian Spectroscopy Conference at Monash University in August 1971, unde…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTQuantun chain process in the sensitized cis-trans photoisomerization of 1,3-dienesJack. Saltiel, David E. Townsend, and Alan. SkyesCite this: J. Am. Chem. Soc. 1973, 95, 18, 5968–5973Publication Date (Print):September 1, 1973Publication History Published online1 May 2002Publ…