Measurements ofg-factor in94Mo

Then _th,α)-reaction spectroscopical data are reported on⁹⁵Mo,¹²³Te and¹⁴⁵Nd (target nuclei). The⁹⁵Mo(n, α)⁹²Zr and¹²³Te(n, α)¹²⁰Sn reactions showed up two lines each corresponding to the ground state and the 1st excited state with a total cross section of 32 ub and 52 μb respectively. In the case of¹⁴⁵Nd(n, α)¹⁴²Ce, a transition only to the 1st excited state of¹⁴²Ce is present. It is shown that in the case of⁹⁵Mo,¹⁴⁵Nd and probably¹²³Te, most of the cross-section comes respectively from the 2⁺ possibly 4^?, and 0 bound levels whose widths are determined to beΓ ^α=0.5 × 10^?6 eV,Γ ^α=1.6×10^?8 eV andΓ ^α=1.6 × 10^?6 eV. The present results on these three nuclei, when combined with the existing data, are consistent with the calculated statistical model values.     

Vacuum UV photoelectron intensity of gaseous compounds: I. HeI spectra of simple compounds

A new method for determining absolute photoionization cross sections for gaseous compounds is proposed. In this method a mixture of a sample and a standard gas (N₂) is used in photoelectron intensity measurements so that the relative intensity of the component is obtained with respect to N₂ The relative photoelectron band area is converted to the absolute photoionization cross section on the basis of the absolute cross-section data of N₂ recently reported by Samson et al. This method has been applied to various aliphatic compounds to study the effect of alkyl substitution on photoionization cross sections of O- and N-nonbonding electrons for 584-Å radiation.     

The effect of anhydrous ammonia on the crystalline-state deformation of nylons 6 and 6,6

The aliphatic polyamides nylon 6 and 6,6 have been cold drawn by using the new concept of reversible plasticization with NH₃. Two aspects were investigated: the effect of NH₃ plasticization on the stress-strain behavior of nylon 6,6, and the extent of NH₃ absorption as determined by x-ray analysis for the structurally simpler nylon 6. X-ray analysis shows that ammonia is absorbed preferentially by the amorphous phase and that the plasticization has a significant effect on the unit-cell orientation, the small-angle void scattering, and the interplanar spacings between sheets of hydrogen-bonded chains. The effect of plasticization was seen in the lower yield stress, the higher draw ratio (up to 8X) and tensile modulus (10 GPa) not attainable with unplasticized specimens.     

Residuenfreie Differentiale und der Cartier-Operator algebraischer Funktionenkörper

Ohne ZusammenfassungThe author acknowledges support received from the National Research Council of Canada, Grant A-7210.Herrn. Prof. E.Lamprecht und Herrn Dr. H.Mathieu dankt Verfasser für ihre Anmerkungen, die zu Verbesserungen der ursprünglichen Fassung führten.     

Novel lactonization of ethenetricarboxylate derivatives: intermolecular trapping of alkenes

A novel cyclization of 1,1-diethyl 2-tert-butyl ethenetricarboxylate (1a) in the presence of a Lewis acid afforded a 5,5-dimethyl-gamma-lactone derivative 2a. The reaction process has been shown to arise from formation by trapping of isobutylene generated in situ. Lewis acid-promoted intermolecular reactions of 1,1-diethyl 2-hydrogen ethenetricarboxylate (5) and various alkenes to afford highly functionalized gamma-lactones were also developed. [reaction: see text]     

Synthesis and fluorescence spectra of oxa[3.n]phenanthrenophanes

[reaction: see text]. Novel photostable oxa[3.n](3,9)- and [3.3](3,10)phenanthrenophanes (n = 3, 4) bearing trimethylene-type linkage(s) were successfully synthesized by the intramolecular acid-catalyzed etherification of the corresponding precursor diols. syn-Oxa[3.3](3,10)phenanthrenophane afforded the most red-shifted excimer fluorescence (lambda(max) = 432 nm) among the phenanthrenophanes so far prepared.     

New source of dense, cryogenic positron plasmas

We have developed a new method, based on the ballistic transfer of preaccumulated plasmas, to obtain large and dense positron plasmas in a cryogenic environment. The method involves transferring plasmas emanating from a region with a low magnetic field (0.14 T) and relatively high pressure (10(-9) mbar) into a 15 K Penning-Malmberg trap immersed in a 3 T magnetic field with a base pressure better than 10(-13) mbar. The achieved positron accumulation rate in the high field cryogenic trap is more than one and a half orders of magnitude higher than the previous most efficient UHV compatible scheme. Subsequent stacking resulted in a plasma containing more than 1.2 x 10(9) positrons, which is a factor 4 higher than previously reported. Using a rotating wall electric field, plasmas containing about 20 x 10(6) positrons were compressed to a density of 2.6 x 10(10) cm(-3). This is a factor of 6 improvement over earlier measurements.