CYCLIZATION OF POLYENES XXX SYNTHESIS OF 2-HYDROXY- AND 1,2-DEHYDRO-7,8-OXIDO-NEPHTENOLS AND CEMBRENOL
Abstract The naturally occurring cembrenoids (I, II, and III) were successfully synthesized, demonstrating unequivocally the assigned structure.
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Calibration of a commercial electron microscope with a grating replica to an accuracy of better than 1%
SUMMARY The method of calibration described in this paper depends on (1) bringing every specimen to the ‘eucentric point’ of a side‐entry goniometer stage to achieve a constant objective magnification, and (2) monitoring changes in the magnification of the projector lenses with a selected area (SA) aperture in the obj…
Diffusion effects in the oxidative degradation of vulcanized rubbers. II. Transient rate of chain scission
Abstract The effect of diffusion in the oxidative degradation of cis ‐1,4‐polyisoprene vulcanizates was estimated by the analysis of the transient state of diffusion and oxidative degradation. An expression for the number of network chain scissions was obtained by solving the diffusion equation, which takes into accou…
Determination of the Crystal Structure of Perovskites with the Space Group I4/mcm
A method is proposed for determining volume ratios of domains in a poly-domain specimen of perovskite crystals with the space group I 4/ m c m ; the ratios are fundamental parameters in determining the crystal structure. The method is based on measuring relative intensities of triplets of Bragg reflexions with special…
Abnormal Undercutting in Etched Cr/Au Films
The etching of gold films deposited on chromium adhesion layers in iodine solution creates cavities at the base of the films. These cavities or abnormal undercutting are revealed and studied by means of the scanning electron microscope. The abnormal undercutting causes the lifting of gold in the etching of high resolu…
On the Difference Between Solid Crystals and Liquid Crystals with Three-Dimensional Order
The most important experimental differences between solid crystals and liquid crystals with three-dimensional order are suggested to be that liquid crystals with optically active molecules form twisted structures, whereas solid crystals do not, and that similar liquid crystal phases of different compounds mix in all p…
Kinetics and Mechanisms of Detergency
It is shown that the kinetic order n and the average soil-removal rate coefficient k of particulate soil detergency can be determined by measuring soil removal during a constant time interval Δ t as a function of soil content of the fabric. With iron oxide as the model soil on cotton poplin and polyester fabrics, the…
The Effect of Age on Amino Acid Composition of Human Skin Collagen
To study the effect of age on amino acid composition of human skin collagen, skins from 8 women aged 0 to 93 were extracted with acetone and EDTA and then gelatinized. Gelatin was purified by extraction with chloroform-methanol and DEAE cellulose chromatography. Hydroxyproline was spectrophotometrically determined and…
Strength, symmetry and distribution of electric quadrupole interactions at181Ta impurities in hafnium-zirconium alloys
The nuclear quadrupole interaction at substitutional Ta atoms in the alloy system Hf x Zr 1-x has been investigated over the entire range of composition by time differential perturbed angular correlations (TDPAC). Source configurations investigated include oriented and randomised single crystals as well as textured, c…
Light Scattering Characteristics in Nematic-Cholesteric Mixtures with Positive Dielectric Anisotropy
The angular dependence of light scattering in nematic-cholesteric mixtures with positive dielectric anisotropy was measured; the quiescent transparent satate S , the focal-conic state F , the storage focal-conic state F 0 , and the field-induced nematic state H were investigated. The F 0 state showed Bragg scattering…
Transient Compensation of Current Transformers
The existence of a siqnificant exponentially decaying dc transient in the primary current of a conventional current transformer leads to large transient values of core flux. Protective scheme design is therefore subjected to constraints, either that ct saturation be tolerated or that larger ct's incapable of saturatio…
Calorimetric studies of poly(ethylene terephthalate) stretching over a wide temperature range
Abstract Heat effects and structural transformations in amorphous crystallizable poly(ethylene terephthalate) (PET) during uniaxial stretching accompanied by neck formation, have been investigated by calorimetric and x‐ray methods over a wide range of temperatures and deformation rates. At small deformation (not excee…
ESCA applied to polymers. XXI. Investigation of sample‐charging phenomena
Abstract Sample‐charging phenomena arising in the ESCA experiment have been investigated for a series of polymers. For samples studied as films or powders mounted insulated from the spectrometer probe and for gold under similar conditions it is shown that over a wide range of operating conditions, equilibrium charging…
PHOTOPHYSICAL PROCESSES IN TROPOLONE, α‐METHOXY‐TROPONE AND COLCHICINE
Abstract— The spectral characteristics of the emission observed from tropolone, α‐methoxy‐tropone and colchicine in EPA at 77 K are reported. Luminescence polarization, lifetime, quantum yield and energy transfer experiments provide evidence that the luminescence observed is S 1 → S 0 fluorescence and that the lowest…
Effects of Corrosion on the Wear Patterns in Horizontal Slurry Pipelines
Electrochemical techniques have been applied to the study of the effect of corrosion on the wear patterns in a 10 cm diameter pilot plant slurry pipeline carrying a freely settling Newtonion slurry of 20 Vol% 30 to 50 mesh silica sand in water. Comparison of specimens with and without cathodic protection made after pe…
Corrosion of Lead Glasses in Acid Media: I, Leaching Kinetics
The leaching kinetics of lead glasses (25 to 35 mol% PbO‐75 to 65 mol% SiO 2 ; some with K 2 O and A1 2 O 3 , additions) were determined in 10% acetic acid. Except for a ternary glass (SiO 2 ‐PbO‐K 2 O) which had a linear dependence on time, all compositions exhibited a linear dependence on the square root of time for…
Microstructure of Poly(1-phenylbutadiene) Prepared by Anionic Initiators
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMicrostructure of Poly(1-phenylbutadiene) Prepared by Anionic InitiatorsToshimitsu Suzuki, Yasushi Tsuji, and Yoshinobu TakegamiCite this: Macromolecules 1978, 11, 4, 639–644Publication Date (Print):July 1, 1978Publication History Published online1 May 2002Published inissue…
Neue ternäre Erdalkaliverbindungen des Arsens mit Mangan / New Ternary Alkaline Earth Compounds of Arsenic with Manganese
Abstract The new compounds CaMn 2 As 2 , SrMn 2 As 2 and BaMn 2 As 2 have been prepared and their structures determined. The crystallographic data are (pm): CaMn 2 As 2 : P3̄m 1, a = 423 ± 1, c = 703 ± 1, c/a = 1.66 SrMri2As2: P3̄m 1, a = 429±1, c = 732 ± 1, c/a = 1.70 BaMn 2 As 2 : I4/mmm, a = 415 ± 2, c = 1347 ± 2,…
Magnetic susceptibility, electrical resistivity, and thermoelectric power measurements ofbis(tetrathiotetracene)-triiodide
The magnetic susceptibility ($\ensuremath{\chi}$), electrical resistivity ($\ensuremath{\rho}$), and thermoelectric power ($S$) of bis(tetrathiotetracene)-triiodide were measured for $9<T<300$ K. Bis(tetrathiotetracene)-triiodide crystals were synthesized by vapor-phase cosublimation. X-ray crystal-structure det…
N-aminoporphyrins. Preparation and metal complexes. Structure of N-tosylamino-5,10,15,20-tetraphenylporphinatonickel(II)
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTN-aminoporphyrins. Preparation and metal complexes. Structure of N-tosylamino-5,10,15,20-tetraphenylporphinatonickel(II)H. J. Callot, B. Chevrier, and R. WeissCite this: J. Am. Chem. Soc. 1978, 100, 15, 4733–4741Publication Date (Print):July 1, 1978Publication History Publis…