Materials Literature
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Elasticity theory is applied to nematic liquid crystals with particular boundary conditions. The calculus of variations is used to derive the torque equations, the solutions of which are found by relaxation methods on a digital computer. These solutions are used to draw pictures of the molecular arrangements and with…
The conductivity of single crystals of tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) was measured over the temperature range 40-300 K. The maximum low-temperature conductivity parallel to the $b$ axis ranged from 12-35 times the corresponding room-temperature value. The temperature dependence of the intrinsic…
Abstract X‐ray measurements as function of temperature were made from pure polyvinyl alcohol (PVA) and concentrated PVA‐solutions in water, glycerine, and glycol. The solutions form gels at adequate low temperatures. As the formation of a chemically bound network can be excluded gel formation must be related to physic…
The regeneration of cellulose from solutions in 85 percent phosphoric acid into glycerol at 170 degrees C resulted in its recovery wholly in the native or cellulose I lattice. Identification of the structure of the regenerated material is based on comparisons of its x-ray diffractogram and its Raman spectrum with thos…
The piezoelectric switching of antiferroelectric domains by the simultaneous application of an electric field E i and mechanical stress T jk is proposed as a direct method for examining whether some spinel compositions do have point symmetry 43m and concomitant antiferroelectric ordering as proposed by Grimes (see abs…
A method that can be easily programmed on a digital computer is presented for optimizing the design of dielectric multilayer filters. Certain rules have been formulated to allow one to construct the electric field transmittance explicitly for any thin film filter system. From the spectral distribution of transmittance…
The tearing energy theory developed to describe the failure properties of vulcanized rubbers is shown to be applicable to the cut growth and fatigue properties of cellular polyurethanes. The effective inherent flaw size to initiate cut growth in the cellular polyurethane predicted from fatigue results has been found t…
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.