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。
Energy transfer from a sensitizer to an activator via Gd 3+ ions is discussed. This is done for the Bi 3+ → Dy 3+ and Sb 3+ → Dy 3+ transfer in , and for the Bi 3+ → Tb 3+ transfer in . The phosphor shows Tb 3+ luminescence with a quantum efficiency of 80% for excitation of Bi 3+ . After excitation of Bi 3+ , energy t…
The processing, structure, and properties of a low-cobalt, ternary Fe-28Cr-10.5Co isotropic magnet alloy (Chromindur II), developed for use in the telephone receiver, are described. The new alloy is easy to process, and permits a convenient low-temperature recrystallization anneal of heavily cold rolled strips leading…
Des séries de ferrites de Li substitués avec du zinc, du titane et du chrome ont été étudiées de 4 à 300 K. Les paramètres hyperfins des différents sites élémentaires de fer ont été déterminés. La variation du champ hyperfin supertransferré Δ HHST due à la substitution de Zn ou de Li en site A, de Ti, de Cr ou de Li e…
Changes in the pH or concentration of sodium silicate solutions produce changes in the degree of polymerisation of the silicate species, and these have been followed by the technique of trimethylsilylation. Provided that the pH remains relatively high, above ca. 10 or 11 according to concentration, equilibrium is rapi…
Using four-circle diffractometry in a dynamic mode, the course of the topochemical photodimerization of 2-benzyl-5-benzylidenecyclopentanone has been determined.
The optical non-linearity of a nematic liquid crystal (NLC) is considered. The strongest effect studied is due to the local turn of NLC director. The possibility of wavefront conjugation by four-wave interaction in a NLC is considered. Strong effects of self-focusing in a NLC due to the orientational mechanism of non-…
Crystal/glass partition coefficients of rare-earth elements (REE), Ba and Sr were precisely determined for the systems prepared by partial melting and partial solidification of high-alumina basalt at 30kb and alkali olivine basalt at 20 and 30kb. At 30kb partial melting produced garnet and clinopyroxene as the solid p…
High temperature (1460°C) hexagonal BaTiO3 was found to be stable at temperatures below 700°C. This structure was stabilized at low temperature by an increase in surface free energy that is significant for small crystallites. The hexagonal phase was a precursor for reversible adsorption and desorption of surface carbo…
Abstract The acicular (needle‐like) clay minerals, sepiolite and palygorskite, were found to be widespread in late Cenozoic sediments of the Texas High Plains. Five soils developed in these sediments, or in materials derived thereform, were analyzed to determine if sepiolite and palygorskite were stable under soilform…
1 Twin intracellular recordings were made from the bag region of Ascaris muscle in order to make conductance measurements. The preparation was bathed in a cool (22 degrees C) Ringer solution to abolish the large spontaneous depolarizing potentials and to improve stability for recording.2 The resting membrane potential…
Abstract Almond shells have been used as raw material to prepare activated carbons. The preparation conditions, by direct activation of the raw material with CO 2 or air, or by activation after carbonisation under nitrogen, have been compared in respect to the percentage burn‐off and the adsorptive properties of the r…
Constitutive laws hitherto applied to two-phase superplastic alloys have not taken into account their two-phase nature. In order to determine the influence of each of the phases on the constitutive laws, α/β brass was studied for different phase fractions and at different temperatures. A constitutive law is found in w…
The effects of carbon formation on methanation activity of nickel and nickel bimetallic catalysts were investigated. Carbon was deposited on these catalysts at 675-700 K, 1 atm, H2/CO = 2 and space velocities of 80,000 to 200,000 h−1 over a period of 6-24 hours. Specific methanation activities were measured before and…
It is shown that two new classes of smectic liquid crystals - esters and salicelidenanilines - have ferroelectric properties. The new ferroelectric smectics have a hightened hydrolitical stability. Their electrical and heat properties are investigated, the correlation between a chemical composition and spontaneous pol…
Abstract A series of polyester polyurethanes with a range of polyester contents was prepared from an ethylene glycol/propylene glycol/adipic acid polyster, butane diol, and methylene bis (4‐phenyl isocyanate) (MBPI). They were thermally degraded under vacuum and the products of degradation were identified. The urethan…
Shear waves are excited in a latex sample. One detects the vibrations of the sample using light scattering phenomena (Kossel rings). The amplitude of vibrations of the latex sample, when recorded as a function of the frequency of excitation, presents a series of resonances. Analysis of the resonance peaks allows to de…
Abstract The kinetics of K adsorption from solution to exchangeable phases were investigated on the Ap, A2, B21t, and B22t horizons of Dothan soil (Plinthic Paleudult) from two locations in Virginia. These soils are loamy sands in the upper horizons with clay content increasing with depth, are slightly acidic in the s…
The ring closure (bleaching) reaction of photochromic indolinobenzospirans is a fast unimolecular process with a finite activation volume. When the reagent is immobilised in a rigid matrix, the isomerization is controlled by the amount of free volume in the neighbourhood of the reacting molecule and so the distributio…
The survival of plant cells may be tested rapidly and conveniently by staining tissue sections in a solution of Evan's blue (0·5% w/v) after exposure to solutions of high salt concentration or low osmotic potential. Living cells retain the ability to exclude Evan's blue at the plasma membrane and remain their natural…
The title crown ether forms three types of compound with lanthanide ions, [M(NO3)3(crown)](M = La—Nd), M4(NO3)12(crown)3(M = La—Gd), and [M(NO3)3(OH2)3]·crown (M =Gd—Lu). Crystal structures of the first and third types have been determined by X-ray diffraction. The complex [La(NO3)3(crown)] is orthorhombic, space grou…