Line parameter measurements and calculations of CO broadened by H2O and CO2 at elevated temperatures

Measurements of collisional broadening of four fundamental CO lines in atmospheres of CO₂ and H₂O at 300–600 K were made. The Voigt line-shape model was fitted parametrically to the absorption spectra line-shapes. The results are compared with other experimental studies and with theoretical calculations for CO₂ broadening. Absorption spectra of the exhaust gases of a flat flame were recorded and analyzed to yield CO concentration, temperature, and line half-widths. The flame spectra half-widths were compared with extrapolations of lower temperature data using the simple power law approximation $\text{γ(T)=γ(T}{}_0\text{) (}\text{T}{}_0\text{T}\text{)}{}^{\mathrm{n}}$. The utility of this approximation in the development of combustion diagnostic techniques is discussed.     

Continuum fluids with a discontinuity in the pressure

A class of one-dimensional continuum fluid models is defined in which classical particles interact through translationally invariant, strongly tempered manybody potentials meeting conditions sufficient to ensure a proper thermodynamic limit. However, an exact analysis demonstrates that for certain ranges of parameter values the pressure versus density isotherms arediscontinuous. The basic models also entail discontinuous temperature versus configurational entropy isobars but extended models are described which exhibit either type of anomaly alone and various unobserved but thermodynamically allowed, anomalous types of first-order transitions.     

Nuclear magnetic resonance study of iron overload in liver tissue

Whole-tissue and homogenized samples of human liver were studied in a NMR spectrometer, T1 and T2 relaxation times were measured as a function of added inorganic or organic iron. When inorganic iron (Fe+3) was added, pronounced T1 and T2 shortening was noted. However, when organic iron, in the form of ferritin, was added, the amount of T1 and T2 relaxation enhancement was much reduced for the same amount of added iron. The in vitro ferritin results model the situation found in clinical studies of hemochromatosis. Only in cases of severe iron overload were significant decreases in relaxation times observed. The T2 relaxation time was the more reliable indicator of excessive levels of iron in the liver. The large range of T1 and T2 values encountered in normal volunteers precludes the use of MR to quantitatively measure iron levels in the liver. The T1 and T2 relaxation times measured at intervals for one individual tend to fluctuate as well, making the use of MR to follow the course of treatment of iron overload disorders unreliable.     

Interactive optimization

Optimization algorithms or heuristics in which the user interacts significantly either during the solution process or as part of post-optimality analysis are becoming increasingly popular. An important underlying premise of such man/machine systems is that there are some steps in solving a problem in which the computer has an advantage and other steps in which a human has an advantage. This paper first discusses how man/machine systems can be useful in facilitating model specification and revision, coping with aspects of a problem that are difficult to quantify and assisting in the solution process. We then survey successful systems that have been developed in the areas of vehicle scheduling, location problems, job shop scheduling, course scheduling, and planning language-based optimization.     

Mode conversion and round-trip gain of ultrasonic flux in n-GaAs

Round-trip acoustoelectric gain has been observed in n-GaAs filaments oriented along the [110] axis. The special conditions required for this effect are obtained through partial conversion upon reflection of active transverse to non-active longitudinal waves. Experiments in which the relative contributions of the two reflected modes to round-trip gain is varied are described.     

Stay time measurements for Xe,Kr, and CO2 physisorbing on Ni and Cu surfaces

A pulsed molecular beam apparatus is used to measure mean stay times for gases physisorbing on cooled surfaces. Most of the data are for Xe on nickel surfaces. Data are also presented for Kr and CO₂ on nickel, Xe on copper, and Xe on ion-sputter-cleaned nickel. All targets are polycrystalline. Surface temperatures range from 92 to 125 K and measured stay times range from 10^?5 to 10^?3 s. Heats of adsorption and pre-exponential factors deduced from the data indicate that the adsorption is localized (immobile) and suggest that the sputter-cleaned targets may be approximately clean. A model relating the shape of the detector signal to the mean stay time is presented and its validity is assessed. Measured speed distributions for the desorbing molecules exhibit an excess of slow molecules compared to that expected for simple effusion. At lower surface temperatures where longer stay times are observed, a peculiar detector signal dip is observed which appears to indicate that the adsorbing beam pulses temporarily reduce the steady state desorption rate of background atoms.     

Asymptotic behavior of the correlation functions for a Brownian oscillator with viscous aftereffects

Correlation functions are derived in explicit form for the asymptotic behavior at for a Brownian oscillator with viscous aftereffects.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 22–25, April, 1973.I am indebted to D. I. Polishchuk and I. Z. Fisher for discussions.     

Evidence for charge Kondo effect in superconducting Tl-doped PbTe

We report results of low-temperature thermodynamic and transport measurements of Pb1-xTlxTe single crystals for Tl concentrations up to the solubility limit of approximately x=1.5%. For all doped samples, we observe a low-temperature resistivity upturn that scales in magnitude with the Tl concentration. The temperature and field dependence of this upturn are consistent with a charge Kondo effect involving degenerate Tl valence states differing by two electrons, with a characteristic Kondo temperature T(K) approximately 6 K. The observation of such an effect supports an electronic pairing mechanism for superconductivity in this material and may account for the anomalously high T(c) values.