Materials Literature
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Abstract The excellent high temperature properties of aromatic polyimides, well known in films and enamels, have also been demonstrated in fibers. Current investigations show that experimental aromatic polyimide fibers have a very high level of thermal and dimensional stability and property retention at high temperatu…
Abstract The kinetics of poly(vinylene carbonate) (PVC) and ethylene carbonate (EC) aminolysis with n ‐butylamine (BA) in DMF solution was investigated. The EC aminolysis is catalyzed by final product and by BA itself but the reaction kinetics follows satisfactorily the equation – d [BA]/ dr = k [BA][EC]; k 2 increase…
A. Sacco and M. Rossi, Chem. Commun. (London), 1967, 316 DOI: 10.1039/C19670000316
Abstract Six of the eight magnetoconductivity components of trigonal Se are measured up to 30 kG over the temperature range 83 to 300 °K. Unlike the Hall mobility, which increases exponentially with temperature, the magnetoconductivity mobility decreases with rising temperature and, at high temperatures, is approximat…
Derivations are given for several expressions relating density expansion coefficients of the net radial distribution function, the direct correlation function, and the x-ray scattering function. To the first order in density, non-additivity effects are included.
各種の金属化合物を触媒として用いて, ビス-β-ヒドロキシエチルテレフタレートの重縮合によってポリエチレンテレフタレート (PET) を合成した。得られたPETの融点およびジエチレングリコール (DEG) 含有量は用いた触媒の種類によって異なり, PETの融点降下は主として副反応によって生成したDEG単位に基いている。さらに, PETのモデル化合物としてβ-ヒドロキシエチルベンゾエートの分解反応を調べた結果, PETの融点降下をもたらしているエーテル結合は主として次の2種類の反応によって生成しているものと推定される。1) 重縮合触媒から誘導されたBronsted酸によるアルコールの脱水縮合。2) PETの末端ヒドロキシエチルエステ…
The red precipitate formed when potassium pertechnetate is reduced with iodide ions is the pentachlorohydroxy-complex K2Tc(OH)Cl5. The compound has a cubic crystal structure and is isomorphous with K2TcCl6. It is paramagnetic and has an electronic spectrum analogous to that of the hexachloro-salt.
Binary mixtures of calcium nitrate with potassium nitrate can be supercooled extensively below their normal solidus temperatures. Comparable binary mixtures have now been studied with sodium, rubidium or caesium as the monovalent cation. Viscosities are in the sequence Na>Cs>Rb>K at high temperatures. On progressive c…
Abstract The isolation, characterisation and chemical investigation of the cardiac glycosides of the dried leaves of Isoplexis isabelliana (W EBB ) M ASF . are described. 7 glucosides B, D, E, J (monoside), K, M, and 1 (monoside) could be obtained in homogenous form, 3 others were mixtures (“A” = A 1 + A 2 , “C” = C 1…
Abstract Mössbauer investigations are reported for five different compositions of gallium iron oxide and for iron‐substitutedβ‐Ga 2 O 3 , and AlFeO 3 . The spectra confirm the ferrimagnetic spin‐arrangement of Ga 2−x Fe x O 3 . Information is obtained on the cation distribution in iron‐substituted (β‐Ga 2 O 3 and Ga 2…
The macroscopic strength of an oriented medium is investigated under the assumption that processes of breaking and reforming of microscopic components in the medium may occur. The differential equation governing the time-dependent variation of the number of load-carrying components is considered. Emphasis is placed on…
This paper reviews methods which have been used to elucidate the quantity Dq in cubic and non-cubic molecules. A novel graphical method allowing the rapid determination of Dq and B from spin-allowed absorption bands of high-spin d 2, d 3, d 7, and d 8 complexes is introduced. It is possible to calculate both in-plane…
A critical evaluation is made of the procedure and the important parameters involved in estimating the stacking-fault energy Γ from x-ray diffraction measurements of deformed materials. The published data for the Ag-In and the Cu-Zn system are carefully analyzed and compared with results obtained by transmission elect…
The effects of stress concentration on the nucleation of deformation twins have been investigated in zinc bicrystals grown with controlled orientations. It is found that the apparent resolved shear stress for twinning varies from 25 to 4900 g/mm2 depending upon the orientations of the individual crystal grains of the…
Radio-frequency sputtering cannot be used for absolute measurements of sputtering yields because of the spread in energies of the bombarding ions. This paper describes how these yields can be studied by simultaneously sputtering with the insulators other materials with known dc sputtering yields. Silicon and germanium…
The adsorption and the reaction rate were studied during the course of the decomposition of formic acid on alumina and silica catalysts and the types of chemisorbed species, their surface concentrations and also the partial pressures of each gases were determined. Accordingly, the dependence of the overall rate upon t…
The five-ball fatigue tester and full-scale rolling-element bearings were used to determine the effect of component hardness differences of SAE 52100 steel on bearing fatigue and load capacity. Maximum fatigue life and load capacity are achieved when the rolling elements of a bearing are one to two points (Rockwell C)…
Abstract The behaviour of single crystal specimens of MgZn 2 deformed by basal slip is investigated by both dynamic and creep tests at temperatures between 250 and 500 °C. With the dynamic experiments a smooth upper yield point is observed. The temperature dependence of the critical resolved shear stress and of the se…
Activation of rare‐earth oxides by ions other than rare earths is successfully attempted in the present investigation. Bi +3 is incorporated in yttrium, gadolinium, and lanthanum oxides by solid state reaction. Probably a chargetransfer mechanism involving bismuth and oxygen introduces an absorption band at about 3200…
The decomposition into nitrogen and hydrogen on heated filaments was studied at pressures of 10–4 torr and less with both conventional and ultra-high vacuum (u.h.v.) techniques. The reaction probability P of an ammonia molecule at a collision with the platinum was determined under various conditions. Particular attent…