Materials Literature
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Abstract The morphological characteristics of poly(ethylene terephthalate) (PET) have been inferred from the selective chemical degradation of amorphous regions, including chain folds, and subsequent analysis of the molecular weight distribution of the reaction products. Bulk PET of known thermal and orientation histo…
The angles of tilt of the anion octahedra in NaNbO3 have been calculated from measurements of the intensities of very weak x-ray difference reflections. Their variation with temperature is shown and compared with values calculated directly from lattice parameter measurements. The Nb displacements have also been calcul…
The X-ray crystal structure analyses of bis-(L-methioninato)cadmium(II), bis-(L-asparaginato)cadmium-(II), triaquabis-(L-glutamato)dicadmium(II) hydrate, aqua-(glycyl-L-glutamato)cadmium(II) hydrate, dichlorobis-(glycylglycine)cadmium(II), and aquachloro(glycylgly-cinato)cadmium(II) are reported; the crystal structure…
Binary blends for two pairs of esters of cholesterol, the myristate plus acetate and the myristate plus the nonanoate have been characterized to determine the equilibrium phase conditions for the isotropic liquid, the cholesteric and smectic mesophases, and the stable crystals. The phase diagrams were determined using…
Abstract Using the method of a modified water‐retention value (LRV), the time dependence and final value of swelling of cellulose in various liquids are found to be determined by the cellulose structure as well as by molar volume and the solubility parameter δ H of the liquid, especially its hydrogen bonding part δ H…
The crystal structure of the title compound has been determined by three-dimensional single-crystal X-ray study from photographic data. Crystals are monoclinic, space group P21/m, with Z= 2 in a unit cell of dimensions a= 7·98, b= 8·10, c= 7·14 (all ±0·02)Å, β= 101·0 ± 0·5°. The structure is built of discrete As4S5 mo…
The sensitized and unsensitized yields of phosphorescence and photoisomerisation of 6-nitro-1′,3′,3′-trimethyl-2′,3′-dihydro-2H-benzo[b]pyran-2-spiro-2′-indole in poly(methyl methacrylate) have been measured at various temperatures. The intersystem crossing yield which equals the unsensitized phosphorescence yield div…
The solid-state i.r. and Raman spectra of the four crystalline phosphorus sulphides, P4S3, P4S5, P4S7, are P4S10 are reported. The Raman spectra of the melts formed by all four compounds, and the vapours formed from P4S3, P4S7, and P4S10 are also recorded. Only P4S3 retains the same structure in all three phases. P4S5…
The structure of synthetic chervetite has been refined by full matrix least-squares to a ω R = 0.029 using 1105 reflections. Unit cell dimensions are a = 13.3689(7), b = 7.1607(4), c = 7.1027(4) Å, β = 105935(5)°, and the space group is P2 1 /a. The structure, originally solved by Kawahara, is a dichromate-type struct…
Abstract Petroplinthite or indurated lateritic concretions have been studied micromorphologically and also with the scanning electron microscope (SEM). It has been shown that the laterite is formed from a kaolinite mass by the absolute enrichment of iron oxyhydrates. In thin‐sections, the iron forms a vacuolar network…
Methods for measuring the strength of a hemispherical shell were developed and applied to SiC coatings obtained from reactor fuel particles. These methods allow independent evaluation of the strengths of the inner and outer layers of the coatings. The applied loads are related to the maximum tensile stress using strai…
Les relations thermodynamiques appliquées aux corps finement divisés conduisent à des expressions liant la température du point triple et l’énergie de changement d’état d’un corps dans un milieu poreux aux courbures des interphases. Un examen de la solidification d’un corps saturant un milieu poreux qu’il mouille, per…
The atomic collision model of fission gas re-solution has been refined by calculating the temperature dependence of the re-solution parameter η. In this way it is shown that the atomic collision model is valid only at T ≳ 400°C whereas in oxide fuels at T ≲ 1000°C a new and more effective re-solution mechanism operate…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPorphyrins. XXVI. Triplet excimer quenching of free base, zinc, palladium, and platinum complexesJames B. Callis, Joan M. Knowles, and Martin GoutermanCite this: J. Phys. Chem. 1973, 77, 2, 154–157Publication Date (Print):January 1, 1973Publication History Published online1…
Comparison of crystal structure parameters obtained for ThCl4 from quantitative X-ray powder data with those available from single-crystal studies has shown that it is possible to obtain reliable parameters from powder studies on simple compounds. Structure refinement based on powder data for ThCl4(R= 8·9%), PaCl4(R=…
The permittivity of doped nematics is found to increase approximately as (1/ω)2 at low frequency. The effect is accounted for by considering the space charge resulting from dissociation of the dopant. The space charge capacitance is obtained from experimental data and compared with that of a simple model.
熱容量が非常に小さい小型の加熱炉をつくり, これを通常の偏光顕微鏡に取りつけた. この高温顕微鏡を用いて, Li2O・2SiO2および33.3Li2O・66.7SiO2・1.5R2O(R; Na, K, Cs) ガラス中に析出する結晶の成長速度を測定した. Li2O・2SiO2ガラス中には, リチウム・2珪酸塩結晶のみが析出した. 成長速度の測定値および結晶成長理論より, この結晶は螺旋転位機構によって成長することが推察された. また, 結晶-融液界面における拡散の活性化エネルギーは, 融液の粘性の活性化エネルギーに等しいことを確めた. 33.3Li2O・66.7SiO2・1.5R2Oガラスからは, リチウム・2珪酸塩結晶とともに…
In material collected in 195? and 19?0 in localities situated between 59° 44' N and 61 °22'N in SW Greenland a total of 465 oligohalobous diatoms and 260 mesohalobous and polyhalobous diatoms is shown, 4 nov. var. and 4 nov. fo. included. A greatnumber of the species and their varieties are not previously shown in Gre…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMechanism and kinetics of calcium sulfate hemihydrate dehydration by nonisothermal and isothermal thermogravimetryVladimir. Satava and Jaroslav. SestakCite this: Anal. Chem. 1973, 45, 1, 154–159Publication Date (Print):January 1, 1973Publication History Published online1 May…
Modified permanent magnets of rare earth cobalt compounds, R(Co, Cu)5, are known as alloys having a complex decomposition mechanism. Studies of the variation of magnetic properties with temperature were carried out for Sm(Co, Cu)5 alloys containing 0 to 75 at% copper. The optimum area for magnetic values was shifted t…