Materials Literature
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An alcoholic extract of Asclepias curassavica L., a plant widely used in folk medicine for treating cancer and warts, shows cytotoxic activity when tested in vitro against cells derived from human carcinoma of the nasopharynx. Systematic fractionation of the extract has led to isolation and characterization of calotro…
Received 13 November 1964DOI:https://doi.org/10.1103/PhysRevLett.13.764©1964 American Physical Society
Received 13 November 1964DOI:https://doi.org/10.1103/PhysRevLett.13.767©1964 American Physical Society
A method is given to calculate the line structure of vibronic bands for a given coupling function p(s), which latter incorporates the frequency and equilibrium change of the oscillator s. The form of the single lines is generally given in terms of their moments. For the important case, where p(s) decomposes into a sum…
By a combination of experimental isotherms and making use of theoretical results, we establish the validity of the theorem of corresponding states for chain liquids and derive an explicit expression for the reduced pressure—volume—temperature surface encompassing oligomer and high-polymer liquids. For this purpose emp…
A four-electron MO treatment of the interaction of the D2h polyacenes naphthalene, anthracene, pyrene, and perylene to yield D2h dimers is developed, and the energies of these dimers are calculated as functions of the effective nuclear charge to be used in a Slater orbital exponent, and of the intermolecular distance…
Abstract Polymerization of 1,3‐dioxolane was examined with organo‐aluminum compounds, acetyl chloride‐metal halides, and acetic anhydride‐perchloric acid as initiators. Poly‐1,3‐dioxolane obtained easily with these initiators was a white crystalline solid with a melting point of 50–55°C. 1,3‐Dioxolanes with a substitu…
The difference of response of Si semiconductor detectors to $\ensuremath{\alpha}$ particles and electrons has been tested. The mean energy required for electron-hole pair generation by electrons has been found to be different from that for $\ensuremath{\alpha}$ particles. These values are, respectively, ${\ensuremath{…
In elastic electron scattering atomic screening is shown to affect the cross section both at very small and at very large angles. However, for energies above approximately 200 keV the large-angle screening effects are small, and the cross section may be written as a product of two factors, one depending on the screeni…
The two-particle cluster approximation of Strieb, Callen, and Horwitz is extended to ferromagnets and paramagnets with nearest-and next-nearest-neighbor exchange, with particular reference to EuO, EuS, EuSe, and EuTe. Curie temperatures, magnetization curves for general values of the applied field, susceptibility, spi…
The optical spectra of the alkali halides are divided into interband scattering and exciton structure. The scattering or direct-transition structure is shown to be similar to that of the zincblende crystals studied in earlier papers of this series. On this basis the band structure $E(k)$ is deduced empirically from th…
Received 3 November 1964DOI:https://doi.org/10.1103/PhysRevLett.13.688©1964 American Physical Society
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChlorinated Xylene Derivatives for Flame-Retardant Rigid Polyurethane FoamsF. B. Slezak, J. P. Stallings, and Irving RosenCite this: Ind. Eng. Chem. Prod. Res. Dev. 1964, 3, 4, 292–294Publication Date (Print):December 1, 1964Publication History Published online1 May 2002Publ…
Cancrinites of compositions 3NaAlSiO 4 XCaCO 3 ,3NaAlSiO 4 XCa(OH) 2 and 3NaAlSiO 4 XK 2 O 3 were made in the 200 degrees to 800 degrees C range at 10,000 to 30,000 psi of water pressure. The first two compositions did not dissociate at upper pressure and temperature limits but the third composition dissociated to nep…
The vapor pressure of plutonium dioxide (PuO 2 ) was investigated in the range 1450° to 1775°C in air, argon, and oxygen atmospheres by a transpiration technique. There were strong indications that PuO 2 can vaporize congruently or as a suboxide species, depending on the atmosphere. The δH° 298 for vaporization in 1 a…
Several routes to the synthesis of 1,4-disubstituted bicyclo[2.2.2]octanes have been explored and the syntheses of several such derivatives are reported. The 1,4-disubstituted bicyclo[2.2.2]-octane nucleus could not be prepared through an elimination reaction on a corresponding 2,5-disubstituted derivative or by the D…
By using the double resonance method, transitions F =5→ F =4 and F =3→ F =2 are measured for 7 2 P 3/2 and 8 2 P 3/2 states of Cs 133 atom ( I =7/2). Frequency shifts proportional to the input power are observed. In order to compare with the experiment, the theory of frequency shift due to radiation is generalized to…
Irradiation of dibenzoylmethane in benzene gives tribenzoylethane. In more concentrated solution a solid dimer (II) separates which, on solution, is converted by dealdolization into an isomer. This isomer (I, R = H) on irradiation, gives tribenzoylethane in a photolytic reaction which has been shown to have some gener…
A study was made of cavitation induced in water at the center of a 12-liter spherical resonator at a frequency of 25 kc/sec. For water degassed so that the equilibrium air pressure above it was less than 4 mm Hg, the threshold was found to be 9±3 atm, provided that the sound field was not radically different from an i…
The volatility of UO 2±x and the phase relations in the system uranium‐oxygen were studied using thermogravimetric techniques. Chemical reactions describing the loss of uranium from UO 2±x at temperatures between 1100° and 2200°C in oxygen pressures between approximately 10 2 and 10 −6 torr are proposed. Results were…