Materials Literature
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Calorimetric and dielectric measurements have been made on Rb${\mathrm{H}}_{2}$As${\mathrm{O}}_{4}$ in the vicinity of the temperature of the ferroelectric transition 109.75 K. The transition is found to be first order with latent heat 255 \ifmmode\pm\else\textpm\fi{} 5 J/mole. The total transition entropy is found to…
Different polyamides and polysulfonamides were prepared by the interfacial polycondensation method. The influence of the experimental condition was specified. The principal characteristics of polymers are indicated (solubilities, molecular weights, IR spectra, thermal stability). In the case of poly(ethylene 1,3-benze…
The use of the nephelauxetic ratio for the calculation of percent covalency is examined. Values of Fk and Ek obtained from four parameter fits (e.g. F 2, F 4, F 6 and ζ4f) neglecting configuration interaction for Pr3+ in various host lattices are compared to those of the free ion. By including the effects of 4f-ligand…
We have carefully determined the optical spectrum of ${\mathrm{K}}_{2}$Pt${(\mathrm{CN})}_{4}$${\mathrm{Br}}_{0.3}$ \ifmmode\cdot\else\textperiodcentered\fi{} 3${\mathrm{H}}_{2}$ O near the reflectivity edge. Our data reveal, in addition to the expected monotonic background, a broad peak in ${\ensuremath{\epsilon}}_{2…
Knitting machine settings and their effect on fabric distortion are examined, and this information is related to finishing procedures involving heat setting and chemical finishing systems. Experiments with a cotton/polyester double knit show that acceptable shrinkage values can be achieved by a combination of careful…
Dye sensitized photooxidation of 1,3-diphenyl-2-pyrazoline in methylene chloride yields 1,3-diphenyl- pyrazole and in methanol yields 1,3-diphenylpyrazole and β,β-dimethoxypropiophenone. The formation of 1,3-diphenylpyrazole is quenched by the singlet oxygen quencher β-carotene, whereas the formation of β-dimethoxypro…
ENDOR spectroscopy has been used for the precise measurements of the proton couplings in two different radicals derived from 1-methyl uracil by gamma ray irradiation. Couplings of the protons located in as many as seven molecules in the host crystal around the free radical have been identified. The intermolecular spin…
The optical properties of benzene, pyridine, quinoline, and 2-ethylnaphthalene in the liquid state have been studied for photon energies from 2 to 10.6 eV. For each liquid the extinction coefficient k has been obtained from transmission measurements, and self-consistent values of the refractive index n calculated over…
Ultrasonication of Merino wool in formic acid liberates cuticle and then orthocortical cells. Further treatment produces a mixture of orthocortical and paracortical cells and finally a clean sample of paracortical cells is obtained.
Mössbauer and crystallographic investigations were carried out on DyFe3−x Nix compounds crystallizing in the PuNi3 type of structure. The hyperfine field observed at the iron sites shows a maximum at x =0.75. The 12-line spectrum observed at room temperature corresponding to the two different kinds of iron in the stru…
Abstract The resonance Raman spectra of cyano‐and aquocobalamin have been obtained from aqueous solutions. In order to check the vibronic theory of Raman intensity in the rigorous resonance case, the excitation profile of the 1502 cm −1 vibration was measured and analyzed using a model of two displaced harmonic oscill…
Abstract The thermal decomposition of silver(I) oxide and its reduction with reductive gases, such as ethylene, hydrogen, and carbon monoxide, have been studied by using a fixed-bed flow reactor. Under isothermal conditions, each reaction gave a sigmoidal shape to the fractional decomposition vs. time curves, and thes…
Auger electron spectroscopy was used to characterize grain‐boundary chemistry in MgO, Al 2 O 3 , and MgAl 2 O 4 (spinel) hot‐pressed with LiF or NaF. The presence of additives (F, Na) at the grain boundaries was confirmed; observation of grain‐boundary impurities in MgO extends previous studies.
CaC6HdO7 .3H20, prepared by slow precipitation from an aqueous mixture of calcium chloride and sodium citrate at a pH of 4.0, is monoclinic, P21/c, with Z = 4 , a=8.7955 (54), b=5.5891 (15), c=23.8176 (175) A, fl= 116.770 (57) °, F.W. 284.2, V= 1045.35 A 3, Dx = 1.806 g cm-3, Dm= 1.79 g cm -3; 2(graphite monochromatiz…
Abstract New series of diamines having pyridine rings and o ‐, m ‐, or p ‐phenylenedioxy linkages were prepared by condensation of chloronitropyridine with isomeric dihydroxybenzenes followed by chemical reduction. The polymerization of the diamines with benzo‐phenonetetracarboxylic acid dianhydride gave polyamic acid…
Abstract Aromatic benzimidazole polymers have been prepared by reaction of the corresponding tetraamine and diester in refluxing sulfolane or phenyl sulfone. The convenience of using these sulfone solvents together with the good yields, high viscosities and absence of crosslinking make this procedure an attractive new…
Abstract Creep tests at constant values of tensile stress, temperature, and relative humidity for two thermoplastics were conducted for approximately 132,000 hr. The strains, ϵ, for the first 2000 hr of time, t , were described by an equation of the form ϵ = ϵ o + ϵ + t n where all other symbols are constants. This eq…
A quantitative analysis of the effect of spin lattice relaxation rates on pure quadrupole resonance pulse experiments for spins with I = 1 is given. A model is presented in which the three dimensional relaxation problem is reduced to a two dimensional one. In this model any possible population distribution of the ener…
The effect of the magnetic transition on the optical-absorption edge has been studied for three antiferromagnetic crystals, MnO, $\ensuremath{\alpha}\ensuremath{-}\mathrm{MnS}$, and CoO. MnO shows a red shift, whereas $\ensuremath{\alpha}\ensuremath{-}\mathrm{MnS}$ and CoO show a blue shift. The observations can be sa…
Flat surfaces of MgO and KCl crystals and teflon sheet were coated with gold evaporated films except for the parallel strip areas approximately 200, 100 and 50 µm wide, and the strip areas without coating were observed by SEM at 15 kV. The images of the uncoated areas were distorted by the surface potential caused by…