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。
The field induced cholesteric-nematic transition is discussed for the case where the helical axis is parallel to the plane of the sample. Approximate solutions for the critical field are presented for both homeotropic and planar boundary conditions.
Experiments with copper in acidified dichromate solutions have shown that a magnetic field can enhance the rate of diffusion-controlled corrosion. Care should be taken in chemical and electrochemical industries to keep hardware susceptible to corrosion away from the domain of magnetic fields.
Four 18-oxygenated pregnane-type steroids ; 18, 20-epoxypregn-5-en-3β-ol acetate (III), 18, 20-epoxy-isolineolon cyclic sulfite (VIII), 18, 20-epoxy-deacyl condurangogenin C (XVIII), and 18, 20-epoxy-20-epideacyl condurangogenin C (XXI) were synthesized, and their structures were established by chemical and spectral s…
Spherically agglomerated crystals of aminophylline were prepared directly during reaction in liquid by the "spherical crystallization" technique. Agitation of a mixture of chloroform, ethanol (or methanol) and water containing ethylenediamine and theophylline yielded spherically agglomerated crystals, the size of whic…
Experimental values are reported for the splay/twist viscoelastic ratios of OHMBBA in the nematic region as a function of temperature. In the experiments the homodyne self-beat technique was used to detect noise intensity spectra of laser light scattered by the nematic liquid crystal. The measured rotational viscosity…
This paper is concerned with a method for calculating the thermal-stress distribution in a nonhomogeneous medium whose shear modulus and coefficient of thermal expansion are assumed to be functions of z. The solution of the problem is determined by using displacement functions. A solution is then derived for the therm…
A generalized maximum determinant rule is shown to be equivalent to maximizing the integral, of the logarithm of the electron density, i.e. equivalent to the 'maximum entropy method' (MEM) of image reconstruction. Relations between the structure factors and the Fourier coefficients of the reciprocal of the electron de…
Riverside nontronite, a candidate for the major mineral in the Martian fines, becomes both redder and darker upon shock loading between 180 and 300 kbar. The change from olive‐yellow (2.5 Y 6/6) to strong brown (7.5 YR 4/6) in the 300‐kbar sample brackets the range of color observed at the Viking lander sites. Optical…
Some derivatives of the homologous series of 4-cyanophenyl-3-methyl-4-(4-n-alkoxycinnamoyloxy) benzoates and of 4-cyanophenyl-4-(4-n-alkoxy-α-methyl cinnamoyloxy) benzoates have been synthesises. The higher homologs of these series exhibit reentrant nematic phases at atmospheric pressure.
The synthesis of LaCrO3 from the mixture of chromium hydroxide and La2O3 was studied under hydrothermal conditions and in air. LaCrO3 was directly prepared under hydrothermal conditions of above 400°C under 100MPa H2O pressure in contrast to the formation of LaCrO3 via La2CrO6 above 700°C in air. LaCrO3 synthesized un…
Abstract The chemical and physical characteristics of a ruthenium catalyst used in the hydrogenation of benzene to cyclohexene has been investigated. The active catalyst consists of metallic ruthenium obtained by hydrogen reduction of the precursor suspended in the alkaline aqueous phase. The precursor consists of hyd…
Abstract Die neuen Verbindungen Ca 3 Si 2 As 4 , Ca 3 Ge 2 As 4 , Sr 3 Si 2 As 4 und Sr 3 Ge 2 As 4 kristallisieren monoklin mit folgenden Gitterkonstanten: Ca 3 Si 2 As 4 : P2 1 /c, a = 730,3(6) pm, b = 1 773,0(7) pm, c = 715,5(6) pm, β = 111,66(8)° Ca 3 Ge 2 As 4 : P2 1 /c, a = 730,8(6) pm, b = 1 788,6(7) pm, c = 72…
A flat washer test for assessing the rolling contact fatigue performance of bearing materials is described in detail. Measurements of the life of commercial bearing quality SAE 52100 steel has established the baseline against which the relative performance of different steels or developments in heat treatment and bear…
The morphological study by scanning electron microscopy (S.E.M.) and crystallographical characterization by transmission electron microscopy (T.E.M.) of needle-shaped calcite microcrystals allowed to put in evidence a jagged needle habit that could correspond to a rapid and differentiated crystal growth, followed by d…
57Fe Mössbauer spectroscopy has been combined with bulk magnetic measurements to determine the valence state and coordination of iron as well as the magnetic properties of the ternary oxide glasses, Li2O-B 2O3-Fe 2O3. In all investigated glasses (≤ 8.4 at % Fe), the Fe3+ ions coexist in tetrahedral and octahedral coor…
Phase equilibria in the Co-Cu-Mn and Co-Cu-Ni systems at temperatures between 1150 and 1550 K were studied by using a ternary diffusion couple technique, which enabled us to get much information over a wide range of composition from a few specimens.Computer calculations based on the thermodynamics were carried out on…
The coherent X-ray diffraction experiment may be used to determine an electron density matrix for a crystal. Equations are displayed whose purpose is to convert measured scattering intensities (or structure factors) into a density matrix corresponding to a single determinant of molecular orbitals. With H and H2 as mod…
Iron-doped single crystals of the zircon-structure orthophosphates LuPO4, YPO4, and ScPO4 have been grown by means of a flux technique. Corresponding powders have been prepared independently by a urea precipitation technique and electron paramagnetic resonance measurements demonstrate that the Fe3+ impurity is situate…
The formation of hyperstoicheiometric oxides of UO2 by the incorporation of additional oxygen atoms in the parent fluorite structure is described in terms of 2 : 2 : 2 oxygen clusters. A 2 : 2 : 2 cluster between two uranium atoms is treated as a co-ordination defect and consideration of electrostatic and polarisation…
An experimental technique has been designed and tested to determine the dynamic yield curve of a rod in compression at high strain rates (∼104−106/sec). The technique involves impacting a gas‐gun accelerated cylindrical rod onto an identical stationary rod at high velocities, and using a high‐speed framing camera to t…