Electronic structure of amorphous transition metal alloys

The electrical resistivity, the Hall coefficient and the magnetic susceptibility of amorphous alloys (Metglass 2826A, Allied Chemical) have been measured above room temperature. The experimental data show strong similarities with liquid alloys.     

Elastic scattering of 0.5 MeV gamma rays by heavy elements

The absolute differential cross sections for the elastic scattering of 0.511 MeV gamma rays were measured in the angular range 0.5? to 10? for the elements withZ=72 toZ=92. The experimental method, employing annihilation radiation in coincidence, permits the investigation at very small momentum transfer. In general the results obtained are in very good agreement with the predictionZ ² r ₀ ² for the differential Rayleigh cross section atθ=0? and with the form factor theory, using Hartree-Fock-Slater wave functions, for the investigated angular range. However, for the elements lead, bismuth and thorium we found marked deviations from the form factor predictions, occurring at very small scattering angles. This is attributed to an outer atomic charge distribution different from the other investigated elements, which is also indicated by considerably greater metallic radii. Also effects due to the crystalline structure cannot be excluded. — Further, an elastic, resonance-like andZ-dependent scattering effect by bound electrons is discussed which is due to the formation of an intermediate, bound positronium state by electron-positron pairs.     

A multi-ion sensor cell and data-acquisition system for flow injection analysis

The flow-injection system described is used for the determination of four ions simultaneously with detection by solid-contact polymer-membrane ion-selective electrodes. The construction of the flow cell and data-acquisition system are discussed. The programming language FORTH facilitates the fast data acquisition required for flow injection analysis. The utility of the system is demonstrated by applying it to the simultaneous determination of potassium, calcium, nitrated and chloride in soil extracts; the results are compared with standard procedures.     

Synthesis and Absolute Configuration of Naturally Occurring Dactyloxene-B and -C

Natural (+)-dactyloxene-B (12) and -C (13) have been synthesized starting from (+)-trans-2, 5, 6-trimethyl-l-cyclohexene-l-carbaldehyde (1) which is shown to have the (5S, 6R)-configuration by chemical correlation with (+)-(2R, 3S, 6S)-2, 3, 6-trimethylcyclohexanone. The absolute configurations are therefore (2R, 5R, 9S, 10R) for (+)-dactyloxene-B and (2R, 5S, 9S, 10R) for (+)-dactyloxene-C.     

New evidence for the P11 (1470) resonance in π + p → n + π below 600 MeV

The differential cross section for π⁻p → nπ^o has been measured in detail from 150 to 600 MeV. The backward cross section has a previously unobserved dramatic dip at 425 MeV. We interpret this dip in terms of interference between the P₃₃(1236) and the P₁₁(1470) resonances. These data provide strong evidence for the adequacy of the phase shift solutions in this energy range.     

Relatively pseudocomplemented semilattices amalgamate strongly

Letk be any finite or infinite cardinal andS _ω the symmetric group of denumerable infinite degree. It is shown that fori<k ifG _i is thei-th row of a matrix whose columns are allk-termed sequences of elements ofS _ω in each of which all but a finite number of terms are equal to the identity ofS _ω thenG _i 's (withG _i ⁻¹ 's defined in an obvious way and with coordinatewise multiplication amongG _i 's andG _i ⁻¹'s) generate the Free Group onk free generatorsG _i . Analogously, Free Abelian and other types of free groups are also constructed. Presented by L. Fuchs.     

Selektive Funktionalisierung von Wortmannin mit Hilfe einer Furanring-Maskierung

Wortmannin ( 1 ) and its 11-desacetoxy derivative 2 are highly susceptible to nucleophiles, which limits the possibilities of transformation. Masking the furan ring by a new method allowed selective transformations with various reagents.     

Die Synthese von 3β-Acetoxy-24-aza-24-desoxa-xysmalogenin,. Partialsynthetische Versuche in der Reihe der Herzgifte. 12. Mitteilung,

Synthesis of 3β-acetoxy-24-aza-24-desoxa-xymalogenin Starting from the pregnenolone-derivative 1 we report the synthesis of the possibly cardiac-active compound 24-aza-24-desoxa-xysmalogenin 15 .     

Hopping conductivity in amorphous carbon films

The electrical resistivity of amorphous carbon films getter-sputtered at 95°K is well fitted between 300 and 20°K by the relation $\text{? = ?}{}_0\text{exp}\text{[(T}{}_0\text{/T)}{}^{\mathrm{<mtext>1</mtext><mtext>4</mtext>}}\text{]}$ with T₀ ? 7 × 10⁷K. This behavior suggests a hopping conductivity very similar to that found in other amorphous semiconductors.