24,612 research outputs found
potential from AdS-CFT relation at : Dependence on orientation in internal space and higher curvature corrections
Within the classical approximation we calculate the static
potential via the AdS/CFT relation for nonzero temperature and arbitrary
internal orientation of the quarks. We use a higher order curvature corrected
target space background. For timelike Wilson loops there arises a critical line
in the orientation-distance plane which is shifted to larger distances relative
to the calculation with uncorrected background. Beyond that line there is no
-force. The overall vanishing of the force for antipodal orientation
known from zero tempera ture remains valid. The spacelike Wilson loops yield a
string tension for a (2+1)-dimensional gauge theory, independent of the
relative internal orientation, but sensitive to the background correction.Comment: Used background has been adapted to hep-th/9808126 and revised
version of hep-th/9805156, slightly changed comment on 1/L ter
Variable energy, high flux, ground-state atomic oxygen source
A variable energy, high flux atomic oxygen source is described which is comprised of a means for producing a high density beam of molecules which will emit O(-) ions when bombarded with electrons; a means of producing a high current stream of electrons at a low energy level passing through the high density beam of molecules to produce a combined stream of electrons and O(-) ions; means for accelerating the combined stream to a desired energy level; means for producing an intense magnetic field to confine the electrons and O(-) ions; means for directing a multiple pass laser beam through the combined stream to strip off the excess electrons from a plurality of the O(-) ions to produce ground-state O atoms within the combined stream; electrostatic deflection means for deflecting the path of the O(-) ions and the electrons in the combined stream; and, means for stopping the O(-) ions and the electrons and for allowing only the ground-state O atoms to continue as the source of the atoms of interest. The method and apparatus are also adaptable for producing other ground-state atoms and/or molecules
Personnel emergency carrier vehicle
A personnel emergency carrier vehicle is disclosed which includes a vehicle frame supported on steerable front wheels and driven rear wheels. A supply of breathing air is connected to quick connect face mask coupling and umbilical cord couplings for supplying breathing air to an injured worker or attendant either with or without a self-contained atmospheric protection suit for protection against hazardous gases at an accident site. A non-sparking hydraulic motion is utilized to drive the vehicle and suitable direction and throttling controls are provided for controlling the delivery of a hydraulic driving fluid from a pressurized hydraulic fluid accumulator. A steering axis is steerable through a handle to steer the front wheels through a linkage assembly
Temperature dependence of Raman vibrational bandwidths in poly(rA) and rAMP
Isotropic and anisotropic spontaneous Raman spectra were obtained from solutions of poly(ra) and rAMP in buffer. The temperature dependence of these spectra was measured to elucidate the influence of macromolecular dynamics and solvent dynamics on the bandwidths of base vibrations in the single stranded polynucleotide poly(rA). The temperature dependence of a bandwidth depends upon the particular vibration under study. The bands can for the larger part be described by Lorentz functions. When fitted by Voigt functions, maximally 10% of each bandprofile of the adenine base vibrations can be attributed to a Gaussian component. The second moment has been determined from the spectra for the 725 cm¿1 band. From the second moment and the bandwidth, we were able to deduce that the vibrational oscillator is in the fast modulation limit. The determined timescale (perturbation correlation time 0.13 ps) eliminate perturbations connected to long range diffusion like concentration fluctuations (timescale in the order of 10 ps). The spectra were analyzed by an extensive curve fitting procedure providing accurate bandparameters (position, width and integrated intensity). The 725 cm¿1 band of adenine has a bandwidth which is dependent upon the degree of polymerization. In RAMP it is 17.6 cm¿1, in stacked (i.e. low temperature 5°C) poly(rA) it is 11.5 cm¿1. The bandwidth of the adenine vibration at 1336 cm¿1 cm¿1 has a temperature dependence which is similar to the intensity changes of the Raman and the absorption hypochromic effect as a function of temperature. The melting transition can therefore be followed by the changes in bandwidth of suitable vibrations
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