Materials Literature
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This study was undertaken in order to analyse the importance of the pumping effect on clothing's thermal insulation. To enhance differences in heat exchanges due to the pumping effect, two sets of condition were fixed, minimizing either the convective or the radiative heat transfers. The results showed that: (i) the c…
Abstract The kinetics of the anionic polymerization of ϵ‐caprolactone, including the kinetics of macrocyclization and the kinetics of macrocycles propagation in THF solution, initiated with (CH 3 ) 3 SiONa, were investigated. Rate constants of propagation ( k p( n ) ) and of back‐biting ( k d( n ) ) involving monomer…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLiquid crystalline solvents as mechanistic probes. 11. The syn .fwdarw. anti thermal isomerization mechanism of some low-bipolarity azobenzenesJoseph P. Ortruba III and Richard G. WeissCite this: J. Org. Chem. 1983, 48, 20, 3448–3453Publication Date (Print):October 1, 1983Pu…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNegative ions: effect of .alpha.- vs. .beta.-silyl substitution on the negative ion states of .pi. systemsJudith C. GiordanCite this: J. Am. Chem. Soc. 1983, 105, 22, 6544–6546Publication Date (Print):October 1, 1983Publication History Published online1 May 2002Published ini…
X-ray analyzer, and 3) the digital scan
The triboluminescent spectra of a variety of glasses and of crystalline quartz were measured while specimens were cut with a rotating diamond-impregnated saw blade. The spectra, which resemble the emission of a blackbody radiator, were recorded using an image-intensifier spectrograph. The data were intensity-corrected…
Abstract Experimental studies of fiber wet‐spinning and solution processing of films of molecular composites are presented. The rigid rod polymer was poly (p‐phenylenebenzobisthiazole) (PPBT) and the flexible polymers were poly (2,5(6′)‐benzimidazole) (ABPBI) and poly (2,5(6′)‐benzothiazole) (ABPBT). Effects of the fl…
Magnetic phase transitions in itinerant electron magnets Hf 1- x Ta x Fe 2 have been studied from measurements of Mössbauer effect, magnetization and X-ray diffraction. The first order magnetic phase transition from ferromagnetic to antiferromagnetic state has been observed with increasing temperature in the Ta concen…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConversion of nitrogen dioxide, nitric acid, and n-propyl nitrate to nitric oxide by a gold-catalyzed reduction with carbon monoxideMark J. Bollinger, Robert E. Sievers, David W. Fahey, and Frederick C. FehsenfeldCite this: Anal. Chem. 1983, 55, 12, 1980–1986Publication Date…
The stimulated emission cross section for the2F5/2→2F7/2transition of Yb3+has been determined from absorption and emission measurements of 41 different oxide, fluoride, and oxyfluoride glasses at 293 K. The effective peak cross sections for transitions to Stark levels above the ground state range from approximately 0.…
An Euler equation, consistent with Maxwell's equations, for describing the optically induced spatial reorientation of the director of a homeotropically oriented nematic liquid crystal is obtained for the case of normal incidence. The exact solution describing the orientation of the director is obtained. By examining t…
The mechanical properties of alkoxy‐derived, high‐purity, translucent, theoretically dense mullite (3AI 2 O 3 .2SiO 2 ) were investigated over the temperature range room temperature to 1500°C. Large agglomerates were found to contribute to the formation of porosity nests which act as strength‐controlling flaws at room…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolymer-polymer diffusion in meltsFrancoise Brochard, Jacqueline Jouffroy, and Paul LevinsonCite this: Macromolecules 1983, 16, 10, 1638–1641Publication Date (Print):October 1, 1983Publication History Published online1 May 2002Published inissue 1 October 1983https://pubs.acs…
A silicon mask-etching technique was used to prepare grooved surfaces that control the direction of outgrowths of human gingival explants. The method used to produce the grooves is excellent in terms of both the uniformity of the grooves and the control with which surfaces of the desired specifications can be obtained.
Constitutive equation for the nematic liquid crystals under weak velocity gradient is derived from the kinetic equation presented by Doi. The constitutive equation is consistent with the phenomenological equation proposed by Ericksen and Leslie. The six viscosity parameters (Leslie coefficients) appearing in the pheno…
Measurements of polarization versus applied electric field have been made on specimens of lead zirconate modified with Sn4+ and Ti4+ as a function of temperature. These data were analyzed to estimate the amount of hysteretic loss which may be encountered in heat-to-electrical conversion using this ferroelectric. The h…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSapphyrins: novel aromatic pentapyrrolic macrocyclesVictor J. Bauer, Derrick L. J. Clive, David Dolphin, John B. Paine III, Francis L. Harris, Michael M. King, John Loder, Shen Wei Chien Wang, and Robert Burns WoodwardCite this: J. Am. Chem. Soc. 1983, 105, 21, 6429–6436Publ…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA new, effective catalytic system for epoxidation of olefins by hydrogen peroxide under phase-transfer conditionsCarlo Venturello, Enzo Alneri, and Marco RicciCite this: J. Org. Chem. 1983, 48, 21, 3831–3833Publication Date (Print):October 1, 1983Publication History Publishe…
Complex mathematical models are increasingly being used as predictive tools and as aids for understanding the processes underlying observed chemical phenomena. The parameters appearing in these models, which may include rate constants, activation energies, thermodynamic constants, transport coefficients, initial condi…
It is proposed to apply the direct measurement of spontaneous polarization using triangular waves to ferroelectric liquid crystals. The use of the triangular waves allows us to easily subtract the background contribution due to the conductive and the capacitive current and to accurately determine the spontaneous polar…