Materials Literature
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High-temperature treatment of thermosensitive dna mutants lysogenic for phage lambda leads to prophage induction and release of phage (at the permissive temperature) in elongation-defective mutants of the genotypes dnaB, dnaE, and dnaG. In initiation-defective mutants no prophage induction occurs at 42 C in mutants of…
Raman spectra of crystalline polyethylene n-C23H43 and n-C44H90 at pressures as high as 40 kbar have been studied at 77 and 298°K, and five bands characteristic of lattice modes have been observed at various pressures. Each of these bands has been assigned to a lattice mode through symmetry arguments and vibrational a…
An attempt has been made to discover the mechanism of iron cementation in clays by comparing the aggregation effected in dispersed pure mineral clay by its exposure to different stages in the active hydrolysis of a ferric chloride solution. Contact of the clay with the early products of the hydrolysis is apparently ne…
Back scattered, conversion electron, Mössbauer spectroscopy was used to study oxide films formed by the thermal oxidation of iron at 225, 350, and 450 C (437, 662, and 842 F). The technique was found to be useful in the study of oxide films from approximately 50 to several hundred Angstroms in thickness without remova…
ADVERTISEMENT RETURN TO ISSUEPREVArticleBis(trifluoromethyl)acetolactone, a Stable a-Lactone'Waldemar Adam, Ju-Chao Liu, and Oswaldo RodriguezCite this: J. Org. Chem. 1973, 38, 12, 2269–2270Publication Date (Print):June 1, 1973Publication History Published online1 May 2002Published inissue 1 June 1973https://doi.org/1…
Isothermal annealing of thermally shocked UO 2 bars (O/M= 2.00 ±0.01) at 1600°, 1800°, and 2000°C caused crack healing, which was determined from recovery of room‐temperature fracture strength. The activation energy for crack healing was ∼0.5 of that for volume diffusion, and healing occurred at the same rate as grain…
Abstract Earlier theoretical work on aggregation in imperfect gases and in solutions of protein molecules is reformulated here in such a way as to be applicable to a number of aggregation systems in solution. The theory is most easily developed for an “osmotic” solution. It is exact, in principle, and in particular do…
The actions of low symmetry crystalline electric fields and the spin-orbit coupling in the t2g4 electronic configuration have been considered for the interpretation of magnetic data (susceptibility. Mössbauer effect, etc.). The results of numerical calculations of the various spin Hamiltonian parameters (D.E.ḡ.Ā.efg)…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal and molecular structure of a salt of the (o-benzoquinone diimine)tetracyanoiron(II) ionGary G. Christoph and Virgil L. GoedkenCite this: J. Am. Chem. Soc. 1973, 95, 12, 3869–3875Publication Date (Print):June 1, 1973Publication History Published online1 May 2002Publis…
The phase relationships in the six component system NaAlSi_3O_8- \nCaAl_2Si_2O_8-Na_2CO_3-H_2O were determined between 650° and 950°C and 1 kb pressure \nalong the joins Ab_(80)An_(20)-Na_2CO_3 and Ab_(50)An_(50)-Na_2CO_3, both with 10 percent H_2O \npresent. The phase relationships are complex. Crystallin…
Congenitally athymic (nude) mice have been shown to accept for their lifetime full thickness, normal human skin grafts without immunosuppressive therapy. The biological and medical significance of the long-term maintenance of human tissues in nonhuman subjects is discussed.
Lattice constants, grain size, electrical conductivity, and luminescence were measured for sintered BaTiO 3 ceramics doped with 0 to 1.2 at.% rare‐earth ions. BaTiO 3 doped with low levels of rare‐earth ions contains grains 10 μm in size and has lattice constants nearly equal to those of undoped ceramics. In this case…
The elastic constants, thermal expansion, thermal conductivity, and heat capacity are reported for a new class of laser hosts-the silicate oxyapatites. For Ca2La8(SiO4)6O2 the five independent elastic constants obtained from sound velocity measurements are C11=1.71, C12=0.62, C33=1.71, C44=0.52, and C13=0.39×1012 dyn/…
Diffusion in lattice arrays reducible to cubic symmetry can be simulated by Monte Carlo procedures. Tracer correlation factors can be derived for diffusion mechanisms in such arrays which include simple solids with point defects and non-stoichiometric materials with complex defect structures subject to defect-defect i…
The freeze-etching technique was used to examine the effects of fracturing and etching on the appearance of poly-beta-hydroxybutyrate granules from Bacillus cereus. These granules were examined in extracts isolated by hypochlorite or by sonic treatment, and also in fixed and unfixed intact cells; in the latter case th…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTX-ray photoelectron spectroscopic studies on the electronic structures of porphyrin and phthalocyanine compoundsMary V. Zeller and Robert G. HayesCite this: J. Am. Chem. Soc. 1973, 95, 12, 3855–3860Publication Date (Print):June 1, 1973Publication History Published online1 Ma…
The electron-microscope technique of lattice imaging can in favourable circumstances be used to observe the structure of materials directly. The technique is described, and examples of cases in which a direct correlation between image contrast and structural features has been established are given. Procedures for comp…
The optical absorption edge of undoped, lightly Al-doped, and heavily Al-doped Bi12SiO20 single crystals is found to be exponential and follows Urbach's rule with σ0=0.71 at room temperature. The band edge is at 3.25 eV and is broadened by excitons and perhaps by impurities or defects. At 80 °K, the band edge is found…
Abstract The possibility to calculate magnetic moments in elemental disordered systems (amorphous state, lattice distortions, surfaces) using the inhomogeneous electron‐gas model is considered. Therefore a partial summation of the gradient expansion of the kinetic energy density functional is performed, which allows t…
The purpose of this type of experiment is to elucidate structure of the different compounds gradually prepared starting from reaction mechanisms and chiefly from spectroscopic data given perviously to students.