Materials Literature
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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…
Treatment of magnesium or zinc porphyrins with thallium(III) trifluoroacetate, followed by an acidic work-up affords oxophlorins in high yield. The oxophlorin oxygen atom is shown to be trifluoroacetate-derived by the isolation of meso-trifluoroacetoxyporphyrins as stable intermediates; a radical mechanism is suggeste…
A mathematical model is proposed to treat the transient response of a disk electrode to a change in the applied current. The analysis reduces to a well‐defined boundary value problem, which yields solutions in terms of newly defined eigenfunctions. The results allow the determination of time constants characteristic o…
Protoporphyrin IX dimethyl ester acts as a diene in Diels–Alder additions with dimethyl acetylenedicarboxylate and with tetracyanoethylene. The copper(II) complex of octaethylporphin reacts with ethyl diazoacetate to yield mainly two isomeric chlorins formed by carbene addition to the cross-conjugated double bonds on…
In comparison with hen egg white lysozyme, goose lysozyme is known to be aberrant in both its structure and its enzymatic behavior in the presence of polymers of N-acetylglucosamine or cell suspensions of Micrococcus luteus. Our chemical studies show, however, that like the hen enzyme, goose lysozyme has muramidase ac…
The rate of corrosion and total corrosion of mild steel in the presence of chemically prepared ferrous sulphide has been studied. The mild steel appears to corrode by a first order reaction. Continued high corrosion rates are observed in experiments where ferrous sulphide is added semi-continuously. Approximately 10 m…
The dependence of the etch rates of vapor‐deposited binary borosilicate, phosphosilicate, and arsenosilicate glasses on glass composition and per cent buffered HF ( 1 part 48 % HF to 10 parts 40 % NH 4 F ) in water are presented. The etch rates of these doped glasses generally increase with increasing dopant oxide con…