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For boron carbide the limit of the homogeneity range at the carbon‐rich side yet has not been firmly established. During the last twenty years carbon‐rich limiting compositions have been reported corresponding to B4.3C (i.e., ‘‘B13C3’’), B4.0C (i.e., ‘‘B12C3’’) and B3.6C (i.e., ‘‘B11C3’’). By means of quantitative EPM…
Abstract Bei dem Versuch, RbLi 3 [SiO 4 ] darzustellen, entstanden erstmals Einkristalle von RbLi 5 {Li[SiO 4 ]} 2 durch Tempern inniger Gemenge der binären Oxide RbO 0,68 , LiO 0,5 und SiO 2 [Rb:Li:Si = 1,1:3,0:1,0; 600°C; 21 d] in fest verschlossenen Ni‐Bömbchen. Das neue „Lithosilicat”︁ kristallisiert monoklin (Rau…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAnionic polymerization of monomers containing functional groups. 2. Anionic living polymerization of 4-cyanostyreneTakashi Ishizone, Akira Hirao, and Seiichi NakahamaCite this: Macromolecules 1991, 24, 2, 625–626Publication Date (Print):January 1, 1991Publication History Pub…
Abstract By means of X‐ray investigations the structure of the S E and S A ‐phases of the title compounds has been studied. The lattice parameters of the orthorhombic S E structure are given. The thickness of the smectic layers is nearly the same in the S E and S A phases and agrees well with the length of the molecul…
The homologous series of 2,3,6,7,10,11,14,15-octaalkyloxytetrabenzo[a,d,g,j]cyclododecatetraenes (CTTV-n) containing n= 4–15 methylenic units in the alkyloxy substituents has been prepared both by alkylation of octhydroxytetrabenzocyclododecatetraenes (CTTV-OH), and by cyclotetramerization of the corresponding 3,4-(di…
Elastic scattering of relativistic electrons and positrons by atoms is considered in the framework of the static field approximation. The scattering field is expressed as a sum of Yukawa terms to allow the use of various approximations. Accurate phase shifts have been computed by combining B\"uhring's power-series met…
The thermal decomposition of copper(II) oxalate has been studied under vacuum using a constant-volume apparatus and a microbalance; and under dynamic atmospheres of air, nitrogen and oxygen using thermogravimetry and differential scanning calorimetry. The decomposition was found to proceed to copper metal under an ine…
Pronounced antimony surface enrichment on a silica gel surface grafted with Sb2O5 is evident after adsorption of Fe3–, and the surface new phase, presumably FeSbO4, is thermally very stable.
Abstract
Free liquid surfaces in equilibrium are described by the Laplace capillary equation with suitable boundary conditions generally given in terms of the contact angle. By a fortuitous formulation in the axisymmetric case, the second order ordinary differential equation can be reduced to a pair of coupled first-order equa…
Two methods for the measurement of the electron emission currents and the secondary electron yields for electron-irradiated dielectrics are discussed. Experimental results indicate that the dynamic measurement method for the secondary emission yield delta provides yield curves that are significantly lower than those o…
Boron carbides made by hot pressing exist as a single phase with compositions between 10 and 20 atomic percent carbon. The longitudinal and shear ultrasonic velocities were measured on fully dense boron carbides with compositions throughout the single‐phase region. Both longitudinal and shear velocities decreased rapi…
The development of a low-permittivity pressboard obtained by blending polymethylpentene fiber with cellulose fiber is described. The permittivity is 3.5, which is lower than that of conventional pressboard. With this pressboard, insulating characteristics of intercoil models were investigated under lightning impulse a…
The kinetics of catalysis of a number of new and established heterogeneous O2 catalysts have been studied using CeIV as the oxidant via both the disappearance of the CeIV ions and concomitant appearance of O2. The most active of the catalysts tested utilised a PGM(IV) oxide, usually Ru or Ir, prepared by the Adams met…
Abstract Reversible color development induced by near UV light (photochromism) was observed for some crystalline powder of 1,1′-diaryl-4,4′-bipyridinium bis(p-toluenesulfonate). Redox mechanism by the electron transfer from the sulfonate anion to viologen dication is claimed.
3'-epi-19-Norafraside, a 19-norcardenolide glycoside with dual linkages between a cardenolide and 4, 6-dideoxy-galactos-2-ulose, and 12β-hydroxycoroglausigenin were newly isolated from the stems of Asclepias curassavica, along with known glycosides and free cardenolides. The structures were determined by spectral and…
Abstract The addition reaction of 3,6‐dioxaoctane‐1,8‐dithiol with various diisocyanates, proceeding by addition of 1,4‐diazabicyclo[2.2.2.]octane as basic catalyst, was investigated. That way, NCO‐and SH‐terminated linear thiocarbamate telechelics (containing NHCOS‐groups) were synthesized. The structures were eva…
Strength, toughness and microstructure relations in α, α+β and β titanium alloys are reviewed. Quantitative fracture mechanisms of α+β titanium alloys are described from the view point of strain-controlled ductile fracture models based on fracture mechanics. Various strengthening and toughening processes of titanium a…
A prototype of a high performance robotic actuator, based on shape memory alloys (SMA), is proposed. Starting from detailed knowledge about the material behaviour, the most suitable way of heating and cooling is proposed. Furthermore an 'optimal' shape of the active element is determined and a control method based on…
Magnetic properties of single-crystal ${\mathrm{DyMn}}_{2}$${\mathrm{Ge}}_{2}$ have been studied by magnetization measurement in high fields up to 150 kOe and by neutron diffraction. Four magnetically ordered phases have been observed. In low magnetic fields parallel to the [001] direction, collinear antiferromagnetis…