Micron-image transfer system with brightness amplifier in gold-vapor laser

A gas-discharge gold-vapor laser on self-terminating transitions with operating wavelength λ=312.2 nm has been used to develop a highly efficient system for image transfer. An optical scheme and all its parameters have been chosen optimal for image quality. It has been found both theoretically and experimentally that the best results on micron-structure image transfer are obtained with 2–5-times image reduction. Various types of masks have been used. A 1-µm structure has been resolved due to the choice of optimal exposure time of 10 ms under a period of pulse repetition (0.6 – 0.8) ms; in this case, the minimal fringe dimension was ≈2 µm with an image dimension of 2 mm for a laser tube 1.8 cm in diameter.     

Group-theoretic description of external gauge fields

For an arbitrary external gauge field we construct an infinite group which contains all the information about the given field and describes some of its properties. We construct a field representation of the group . We show that covariant derivatives become translation generators in such a representation of the group . This allows us to interpret transformations from the group as motions in an external gauge field.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 31–35, December, 1988.     

Experimental study of regions of reversed magnetization in an amorphous layer of Co70Fe5Si10B15

The characteristics of the distribution of magnetization and remagnetization of microsections of the surface in the amorphous alloy Co₇₀Fe₅Si₁₀B₁₅, prepared in the form of thin ribbons, were studied by the magnetooptical method. It was found that the magnetization I on the surface of the amorphous ribbon studied was strongly nonuniform. It was established that heat treatment (HT) of the sample leads to the appearance of regions of reversed magnetization in the surface layer of the ribbon, while thermomagnetic annealing reduces the nonuniformity of I. The conservation of the transverse component in the HT sample in fields where the magnitude of the component of magnetization parallel to the length of the ribbon remains virtually unchanged suggested that a domain structure of the magnetization ripple type, owing to the strong microdispersion of the magnetic anisotropy, is realized in this sample.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 89–94, March, 1988.     

Computed tomographic imaging of the coronary arterial tree-use of local tomography

It has been demonstrated previously (see E.L. Ritman and A.A. Bove, in State of the Art in Quantitative Coronary Arteriography, p.67-78, 1986) that coronary artery anatomy can be visualized using high-speed, volume-scanning X-ray CT (computed tomography). In the current study it is demonstrated that local image reconstruction (i.e. the reconstruction kernel is ~2(+) mm long), as distinct from more conventional global image reconstruction (i.e. 200(+) mm kernel length), has the advantage of reducing the need for operator interactive image processing. In addition, the local reconstruction algorithm eliminates the need for recording the X-ray projection data over the full transaxial extent of the thorax because it requires only the X-ray attenuation data over the region of the heart. This latter aspect reduces the dynamic range requirements for the sensors and could reduce total X-ray exposure.     

Color quantitation through image processing in dermatology

Classical color models and their applications to computer vision are reviewed. The performances of color quantitation from digitized images are compared with those derived from a chromameter. The color quantitation obtained from either digitized color slides or directly digitized images is proved to be more efficient than the conventional visual assessment of observers. A methodology is proposed for determining the specific color indices which are needed in dermatology. An application of this methodology is developed for designing a blanching quantitation index in order to replace the visual assessment during McKenzie tests.     

Untersuchung von Einzelblasen an ölbeschichteten Oberflächen mit künstlichen Keimstellen

Zusammenfassung An feinpolierten, ölbeschichteten V2A-Oberflächen mit jeweils einer gebohrten (d=140 µm) und einer geätzten (d=47 µm) Vertiefung als Keimstelle wurde für Wasserblasen das Wachstum, der Abreißdurchmesser und die Abreißfrequenz gemessen. Für die wärmetransportgesteuerte Blasenbildung liefert der Vergleich mit Beziehungen, die für reine Metallflächen gewonnen wurden, gute Übereinstimmung, so daß keine Einfluß der Ölschicht erkennbar wurde.

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Investigation of single vapor bubbles on surfaces covered with a thin oil film with artificial nuclei

For single vapor bubbles, the growth rates, the detachment diameter, and the frequency were measured on single artificial nuclei, either drilled (d=140 µm) or etched (d=47 µm) into a highly polished stainless steel plate which was covered with a thin oil film. For evaporation controlled by heat transport, good agreement was observed with relations from literature which were obtained for clean surfaces; thus, an effect of the oil film could not be discovered.

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Formelzeichen a Temperaturleitfähigkeit - D _a Blasenabreißdurchmesser - f Blasenfrequenz - Ja Jakob-Zahl - Pr Prandtl-Zahl /a - q Wärmestromdichte - R Blasenradius - T Temperatur - dynamische Zähigkeit - Wärmeleitfähigkeit - Dichte - Oberflächenspannung - Zeit Indizes g Gas, Dampf - l flüssig - s Sättigung - w Wand Herrn Prof. Dr.-Ing. Karl Stephan zum 60. Geburtstag gewidmet     

Theory of surface spin-exchange recombination of spin-polarized hydrogen

Calculations of the two-atom surface recombination rate for spinpolarized atomic hydrogen are carried out. Both the plane-wave Born approximation (PWBA) and the -dimensional distorted-wave model are employed. The field dependence forB=4 to 10 Tesla, and the temperature dependence for 0.2<T<1 K are examined for systems initially consisting of equal numbers ofa- andb-state atoms. The rates are analyzed with respect to para- and ortho-H₂ production, and to recombination to various vibrational and rotational states of H₂. The PWBA gives reasonable agreement with experiment with respect to the field-dependence and ortho-para production, but predicts an overall rate a factor of 40 above experiment. The -dimensional model underestimates the rate by a factor of 10³ and yields poorer agreement with experiment than the PWBA for the field-dependence and ortho-para production ratio. These results point out the need for a proper many-body treatment.     

High dose iron implantation into silicon and metals

High dose implantations of Fe into metals and semiconductors have been performed with beam energies up to 1 MeV at the UNILAC-injector at GSI. Unusual high concentrations of 70 atomic % for Si and 20 atomic % for Cu have been obtained, with doses of 10¹⁸ Fe/cm² in the case of Si and several 10¹⁷ Fe/cm² in the case of Cu. For Si the thickness of the layers were determined by Rutherford backscattering to be 4500 Å. These results are consistent with calculations, which show that these high concentrations are due to the reduction of the sputter yield at the relative high particle energies. Samples have been characterized using several complementary methods (Mössbauer Spectroscopy (MS), Rutherford Backscattering Spectroscopy (RBS), Auger electron Spectroscopy (AES). Scanning Electron Microscopy (SEM), X-ray diffraction (XRD)).     

Solution of the inverse problem for an evolution equation in a Banach space

For the equationdy (t)/dt=Ay(t) + p, t [0, ), where A is a closed linear operator on a Banach space , p is an unknown parameter from , we consider the problem