HTS quasiparticle injection devices with large current gain at 77 K

Recent progress on the development of planar QP-injection devices using YBCO and STO as an epitaxial injection barrier will be discussed. The main problem for HTS injection devices is to grow reliably a well defined, ultra-thin tunneling barrier suitable for QP tunneling. For this purpose, we used inverted cylindrical magnetron sputtering to first optimize the smoothness of our YBCO films by controlling tightly an relevant sputtering conditions. We are able to prepare smooth (001) YBCO films on (001) STO substrates on a routine basis with an average roughness varying between 1 and 2 nm. With these flat YBCO films both planar as well as grain boundary junctions were fabricated using epitaxial STO barriers between 2 and 8 nm thick and a 50 nm of Au counter electrode. Planar junctions with 6 nm STO barriers were in most cases fully insulating, in some cases, a current gain of up to 7.4 at 77 K was obtained. For 3 nm STO barriers, the highest current gain was 15 at 81 K. The injection results also show a scaling behavior with junction size. Based on the present materials development and device understanding, we consider a current gain of up to 20 at 77 K possibl

When is 0.999... equal to 1?

A doubly infinite sum, numerically evaluated at between 0.999 and 1.001, turns out to have a nice value

The NOAA/NESS program for operational snowcover mapping: Preparing for the 1980's

There are no author-identified significant results in this report

NOAA satellite programs and technology requirements

Information concerning NOAA satellite programs is presented in vugraph form. The following topics are discussed: NOAA's space philosophy, the NESDIS FY-93 budget summary, LANDSAT program status, a history of geostationary satellites, the GOES program, current GOES instruments, improved GOES capabilities, polar orbiters, a history of TIROS R&D satellites, a history of ESSA operational satellites, a history of ITOS/NOAA satellites, and a history of TIROS-N/NOAA satellites

The operational program of satellite snowcover observations at NOAA/NESS

The operational river basin snow mapping program at NESS is described with emphasis on quality control techniques and results for the 1974-1975 snow season

Threaded pilot insures cutting tool alignment

Threaded pilot allows machining of a port component, or boss, after the reciprocating hole has been threaded. It is used to align cutting surfaces with the boss threads, thus insuring precision alignment

Non-equilibrium radiation nuclear reactor

An externally moderated thermal nuclear reactor is disclosed which is designed to provide output power in the form of electromagnetic radiation. The reactor is a gaseous fueled nuclear cavity reactor device which can operate over wide ranges of temperature and pressure, and which includes the capability of processing and recycling waste products such as long-lived transuranium actinides. The primary output of the device may be in the form of coherent radiation, so that the reactor may be utilized as a self-critical nuclear pumped laser

Thermal Dileptons from Quark and Hadron Phases of an Expanding Fireball

A fireball model with time evolution based on transport calculations is used to examine the dilepton emission rate of an ultra-relativistic heavy-ion collision. We assume a transition from hadronic matter to a quark-gluon plasma at a critical temperature T_C between 130-170 MeV. We include thermal corrections to the hadronic spectra below T_C and use perturbation theory above T_C. The sensitivity of the spectra with respect to the freeze-out temperature, the initial fireball temperature and the critical temperature is investigated.Comment: 14 pages, 5 figures; paragraph and one figure added; version to appear in Eur. Phys. J.

Pressure effects on the superconducting properties of YBa_2Cu_4O_8

Measurements of the magnetization under high hydrostatic pressure (up to 10.2 kbar) in YBa_2Cu_4O_8 were carried out. From the scaling analysis of the magnetization data the pressure induced shifts of the transition temperature T_c, the volume V and the anisotropy \gamma have been obtained. It was shown that the pressure induced relative shift of T_c mirrors essentially that of the anisotropy. This observation uncovers a novel generic property of anisotropic type II superconductors, that inexistent in the isotropic case.Comment: 4 pages, 3 figure