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An investigation of the inelastic and elastic reactions between high- energy neutrons nnd He nuclei was conducted with a cloud chamber filled with He and operating in a pulsed magnetic field of 21,700 gauss. Neutrons produced by bombardment of a 1/2-in. LiD target with 340-Mev protons in the 184-in. synchrocyclotron were collimated and passed through the 22-inch expansion cloud chamber, which was filled with He gas to a total pressure of 89.8 cm Hg. Exclusive of meson-producing reactions, the possible reactions are: Inelastic, He/ sup 4/(n,pn)t, He/sup 4/(n,d)t, He/sup 4/(n,2np)d, He/sup 4/(n, dn)d, He/sup 4/ (n,2n2p) n, He/sup 4/(n, 2n) He/s up 3/; and Elastic, He/sup 4/(n,n)He/sup 4/. The total number of events, for incident neutrons above 160 Mev, was normalized to the interpolated n-He/sup 4/ total cross section at 300 Mev, and absolute cross sections for the various processes were established. Energy and angular distributions of the reaction products were compared with available theoretical predictions and other experiments. A few cases of meson production were noted. (auth)

An apparatus for rapidly mixing two solutions and recording the light absorption, which was developed by Connick and Below, has been modified. The mixing characteristics were studied and models were developed in an attempt to umder stand the observed mixing phenomena. The apparatus was applied to a study of the kinetics of the reactions Fe/sup +++/ + SCN/sup -/ = FeSCN/sup ++/ and Fe/ sup +++/ Cl/sup -/ = FeCl/sup ++/ in aqueous solution, with both reactions having the forward rate law STAd(FeX/sup ++/)/dt = k/sub 1/ (Fe/sup +++/) (X/sup -/) + k/ sub 2/ (Fe/sup +++/)(X/sup -/)/(H/sup +)!, where X/sup -/ represents either SC N/ sup -/ or Cl/sup -/. The rate constants k/sub 1/ and k/sub 2/ have been measured as a function of temperature, and the heats and entropies of activation have been calculated. Mechanisms for the observed rate law have been discussed and the entropies of activation were compared with those for analogous reaction rates and with some equilibrium entropies of complexing. A rate for chloride complexing of ferric ion was obtained from nuclear magnetic resonance studies and compared with the results of the spectrophotometric kinetic study. (auth)

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As part of a thermodynamic study of NiTe and NiTe/sub 2/, an attempt was made to gather data which would determine zero-point entropies as a function of composition. Part of the necessary data have been gathered, and in addition a number of other pertinent or interesting properties of the nickel tellurides, and of Te, have been investigated. Specific heats from 4 to 350 deg K have been measured on NiTe/sub 1.1/ NiTe/sub 1.5/, and NiTe/sub 2.0/, and the thermodynamic functions of these and all intermediate compositions may be considered accurately known over this temperature range. The method employed was conventional precise adiabatic calorimetry in an existing apparatus. The melting point of Te has been redetermined and the highly discordant literature critically reexamined; the triple point may now be stated with some confidence to be 449.7 plus or minus 0.2 deg C. The dissociation pressures of compositions from NiTe/sub 1.5/ to NiTe/ sub 2.0/ have been accurately measured at temperatures up to 780 deg C in order to determine the partial molal free energies and entropies of Te in these compounds. These measurements have incidentally elucidated the phase behavior in the Te-rich region, showing a high solubility of Ni in liquid …