Excess enthalpies of some 2-alkanone + 1-chloroalkane binary mixtures at 25 and 35°C

Excess molar enthalpies h^E at 25 and 35° C and atmospheric pressure, are reported for the binary mixtures formed by a 2-butanone and 2-pentanone with 1-chlorobutane, 1-chloropentane, 1-chlorohexane, or 1-chlorooctane. The h^E values for all the mixtures are positive, increasing as the 1-chloroalkane length increases and as the ketone length decreases. Excess molar enthalpies depend slightly on the temperature. The experimental values together with those from the literature were used to calculate the interaction parameters for the Dang-Tassios version of the UNIFAC model.Communicated at the Festsymposium celebrating Dr. Henry V. Kehiaian's 60^th birthday, Clermont-Ferrand, France, 17–18 May 1990.     

Nematic LC to nematic glass phase transition in pores

The properties of a nematic liquid crystal in a porous matrix are discussed. On scales exceeding a certain characteristic scale the liquid crystal behaves as a nematic glass. Application of a weak magnetic field restores long-range orientational order. Pis’ma Zh. éksp. Teor. Fiz. 65, No. 9, 695–698 (10 May 1997)     

Ordering of substitutional ternary alloys with an fcc lattice

The possible types of ordering diagrams of ternary substutional alloys with an fcc lattice are analyzed, taking account of interactions in two coordination spheres.Ural Polytechnic Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 38–41, December, 1992.     

Investigation of the fundamental properties of a Coulombian plasma by the method of many-particle dynamics

It is shown that a completely ionized, classical, Coulombian plasma, placed in an adiabatic enclosure, possesses a stationary state. At the same time, a plasma placed in a thermostat recombines through triple collisions, with a velocity satisfactorily accounted for by well-known theoretical results. The results obtained by numerical modeling have shown that, for a plasma placed in an adiabatic enclosure, the ergodic assumption is not valid. Various possible kinetic mechanisms, ensuring the existence of a stationary state of the adiabatically enclosed plasma, are considered.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 3–34, November, 1991.     

μSR in oxygen deficient YBa2Cu3O x (6.5⩽x⩽7.0)

A systematic μSR study of the local magnetic field distribution in a series of oxygen deficient YBa₂Cu₃O _x samples with 6.5⩽x⩽7.0 is reported. Special attention was given to perform the experiments under the same conditions, so that the oxygen content of the measured samples was the only parameter varied. The behavior of the depolarization rate σ as a function of the oxygen contentx was found to have strong similarities with the behavior of the critical temperatureT _c as a function ofx. In particular, two step-like increases of σ were observed abovex=6.7 and 6.9. The temperature dependence of the normalized depolarization rate σ(T)/σ(0) is well described by the two-fluid model forx⩾6.781(1) and clearly deviates from this behavior forx⩽6.704(1). Our results are compared to those obtained by other groups.     

Pion pair production in photon-photon collisions

The process γγ→π⁺π^? was measured using the detector MD-1 at VEPP-4. The two-photon reactionse ⁺ e ^?, μ⁺ μ^? and π⁺ π^? pair production were separated using scintillation counters, Cherenkov counters and shower-range chambers. A radiation widthГ _γγ(f ₂(1270))=3.1±0.35±0.35 keV was obtained.     

Testing deviations from the inverse square law with a freely falling gravity gradiometer at balloon altitudes

Summary We discuss a null experiment to search for the fifth force at ranges around 10 km. It is proposed to use a three-axis gravity gradiometer to measure the trace of the Earth gravity tensor from a freely falling elevator dropped by a balloon. The main error sources are considered to some extent. Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990.     

Optical diagnostics of dispersing He plasma

An experimental study has been made of the characteristics of radiation from a dispersing helium plasma. From measurements of the space-time dependence of the line intensities of the helium 2³P — n³D series we obtained the distribution of the populations of the n³D levels for n=3–10. The study has shown that over a wide range of conditions the high-lying levels (n=5–10) are in equilibrium with electrons while a substantial deviation from equilibrium is observed for levels n=3, 4. From the energy distribution of the populations of the upper levels we determined the space-time dependence of the electron temperature, which reflects the process of effective electron cooling during dispersal of the plasma. The gas temperature was estimated from the populations of helium singlet and triplet levels with n=5. The time distribution of the electron density in the plasma was found from the Stark broadening of the spectral lines.Deceased.V. D. Kuznetsov Siberian Physicotechnical Institute, Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 15–19, November, 1992.