Materials Literature
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Using thermal analysis it is possible to determine solidification rate by measuring the amount of heat emitted by a sample. Different methods of calculating the heat lost under various conditions are discussed. Using solidification rates thus determined, the solidification cycle and solidification kinetics are analyse…
Rings having 10 delocalizable electrons are of interest as potentially aromatic compounds. The unsubstituted 1,4-dihydro-1,4-diazocine (1) has now been prepared by two independent syntheses. Some N,N′-disubstituted derivatives of this ring system were already known. On the basis of its chemical behavior, spectra, and…
The Brillouin and Rayleigh scattering spectra have been observed near the transition temperature T c in the paraelectric phase of KD 2 PO 4 as a function of the direction of the scattering vector q in several scattering geometries. The broad central component ascribed to dynamical spectrum of the Debye type relaxation…
Abstract Cation-exchange equilibrium for Ca-K-montmorillonite was studied at 35°, 50°, and 90°C and at three total normalities of the equilibrium solution (0.1, 0.05, and 0.01 N). Changes of the standard free energy for the exchange from K-montmorillonite to Ca-montmorillonite were determined to be −53, −270, and −393…
The binding of the various substrates to Escherichia coli glutamyl-tRNA synthetase has been investigated by using as experimental approaches the binding study under equilibrium conditions and the substrate-induced protection of the enzyme against its thermal inactivation. The results show that ATP and tRNAGlu bind to…
The microscopic dynamic behavior of some simple liquids has been investigated by observing the time evolution of the separation between members of pairs of atoms. The distribution function for this process was calculated in molecular-dynamics studies of several states of two model fluids: Lennard-Jones and simulated r…
Evidence for reductive carboxylation of succinate to synthesize alpha-ketoglutarate was sought in anaerobic heterotrophs from the rumen and from other anaerobic habitats. Cultures were grown in media containing unlabeled energy substrates plus [14C]succinate, and synthesis of cellular glutamate with a much higher spec…
Topical interest in photochromic systems is due in part to their application in silver-free photography, in data display technology, and possibly even in solar energy storage. The new system (1)⇌(2) is readily accessible and open to wide structural variation.
In Cyelotella meneghiniana the location of the nucleus in the vegetative cell changes as the cell diameter is decreased by successive cell divisions. Other features of the vegetative cell are ultrastructurally similar to other diatoms: chloroplasts are enveloped by chloroplast endoplasmic reticulum; pyrenoids are trav…
Abstract Infrared and Raman spectra (10–4000 cm −1 ) of single crystals and of polycrstalline samples of (NH 3 (CH 2 ) 3 NH 3 )MnCl 4 and of its ND 3 deuterated derivative have been investigated in the 10–400 K temperature range. An assignment of most of the observed bands is proposed. The first‐order phase transition…
Samples from the Antarctic and Subantarctic Zones were used for a study of three taxa of the diatom genus Thalassiosira with circumpolar distribution. Most records were from south of the Antarctic Polar Front Zone. T. perpusilla, T. gracilis var. gracilis, T. gracilis var. expecta, stat. nov., have the longer extensio…
This paper is concerned with the accelerated aging of solid insulating materials, as a means of estimating their service lives and identifying superior dielectrics. The assumed failure mechanism is electric treeing. A constant-stress accelerated aging experiment on a transparent epoxy at three voltage levels is descri…
Ying-Kai Fu, Gary E. Kaufman, Morton W. Miller, T. Dan Griffiths, Christopher S. Lange, Modification by Cysteamine of Ultrasound Lethality to Chinese Hamster V-79 Cells, Radiation Research, Vol. 80, No. 3 (Dec., 1979), pp. 575-580
NO) (43% yield) and (i75-C5H5)Cr(N0)2(N02) (35% yield) under identical experimental conditions.It has previously been reported that the carbonyl dimer in benzene reacts with CO (100 atm) to form [(7j5-C5H5)Cr(CO)3]222 and with phosphines to form unisolable products.Both bimetallic compounds are transformed by C1NO in…
The effect of morphology on the thermal expansion behavior, helium permeability, density, and refractive index of alkaline earth silicate glasses has been determined for the calcium, strontium, and barium silicate systems. These data have been used to determine the miscibility limits and the limits of connectivity of…
Abstract Fe substitution for Al in kaolinite (from Venezuelan laterites) is proved by infrared spectroscopy and chemical techniques. The location of Fe in the octahedral sheet is characterized by two absorption bands, at 865–875 and 3607 cm −1 , assigned as δ Al-OH-Fe and v OH respectively. The detection of the 865 cm…
In a study of the system $^{16}\mathrm{O}$+$^{40}\mathrm{Ca}$, the total evaporation-residue cross section has been measured at nine energies, and elastic-scattering angular distributions at five energies, within the range $40 \mathrm{MeV}\ensuremath{\le}{E}_{\mathrm{lab}}\ensuremath{\le}214 \mathrm{MeV}$. The fusion…
X-ray diffraction patterns of single-domain samples of the smectic $F$ phase of terephthalydene-bis-4-$n$-pentylaniline, obtained by melting single crystals of the crystalline phase, have enabled us to collect important information concerning the nature of this phase. The smectic layers are almost uncorrelated, and wi…
Abstract Based on creep and creep‐recovery measurements, the viscoelastic functions [ J ( t ), J r ( t ), J ′(ω), J ″(ω), G ′(ω), G ″(ω), and L (lnτ)] are presented for solutions of a narrow molecular‐weight‐distribution polystyrene in tri‐ m ‐tolyl phosphate in the concentration range of 1% to 100% polymer. For conce…
The conformations of oxidized and reduced isoalloxazine have been examined by a molecular orbital method, PRDDO (partial retention of diatomic differential overlap). The angle theta of fold about the N...N line of the central ring is zero for the planar oxidized form, but a bend of theta = 10 degrees requires only 2 k…