Robert Hauser

Fachhochschule Kärnten (Feldkirchen), Engineering and IT, Faculty Member

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PhD in Physics.

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Papers by Robert Hauser

A compact spectrometer based on a micromachined torsional mirror device

ABSTRACT We describe a spectrometer employing a microelectromechanical system (MEMS). A torsional... more ABSTRACT We describe a spectrometer employing a microelectromechanical system (MEMS). A torsional micromirror device, which was originally designed for laser scanner applications, has been modified to act as a diffraction grating in a Czerny-Turner setup. This spectrometer system combines the working principle of a scanning monochromator with the compactness of a microsystem. The micromirror device is operated in a harmonic scanning mode at a resonant frequency of 500 Hz, enabling the system to acquire a spectrum per half cycle in one millisecond. The spectra of a calibration source in the visible and near-infrared spectral range as well as simulations concerning the optical system demonstrate the performance of the spectrometer.

<title>A practicable method for color classification using low-cost remission/reflection sensors</title>

Sensors, Cameras, and Systems for Scientific/Industrial Applications VIII, 2007

A low-cost sensor platform (MORES Sensor) was combined with a microcontroller to build up an embe... more A low-cost sensor platform (MORES Sensor) was combined with a microcontroller to build up an embedded solution which e.g. allows for a small hand-held Color Estimation System for blind people. The color sensor used here measures the intensity response of a surface caused by radiation with a specific wavelength in the range of visible light. This radiation is realized by means of three LEDs, red, green, and blue, so that the response intensity values create an R'G'B' color space, which differs from the standardized RGB color space due to the wavelengths of the LEDs. By adjusting the measured response of the LEDs to the known spectral response of the individual color panels of the Macbeth Color Checker Chart (MCCC) a corresponding set of coordinates can be constructed for this particular R´G´B´ color space. Owing to this approach, it is possible to obtain reasonable color classification results, which can be compared to those of far more complex and expensive systems. The verification of the results was done by using the standardized MCCC together with commercial vision solutions (RGB camera in combination with PC software). Moreover, some comparison tests also prove the practicality of the here described low-cost color sensor solution.

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55MnNQR/NMR studies of the magnetic properties ofYMn2under pressure

Physical Review B, 1999

We report magnetic properties of the antiferromagnet YMn 2 as functions of pressure and temperatu... more We report magnetic properties of the antiferromagnet YMn 2 as functions of pressure and temperature ͑T͒ obtained from the 55 Mn spin-lattice relaxation rate and the Knight shift. An energy-band narrowing due to electron correlation is indicated by the Knight shift measurement and the application of pressure is found to enhance the conduction electron bandwidth. In the pressure-induced paramagnetic state, the system undergoes a crossover from an itinerant spin fluctuation ͑SF͒ regime at low T to a local SF regime at high T. It is pointed out that this magnetic crossover of SF resembles that of high-temperature superconductors.

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Pressure Effect on the Spin Fluctuations in YMn2. Mn NQR Study

THE REVIEW OF HIGH PRESSURE SCIENCE AND TECHNOLOGY, 1998

We report the NQR study on the pressure-induced paramagnetic state in the antiferromagnetic (AF) ... more We report the NQR study on the pressure-induced paramagnetic state in the antiferromagnetic (AF) intermetallic compound YMn 2 with the Néel temperature T N =100 K at ambient pressure. From the T variation of the nuclear spin-lattice relaxation rate, 55 (1/T 1) of 55 Mn above the critical pressure of 4 kbar, the spin fluctuation feature is found to change below a temperature T sf. At higher temperature than T sf , the nuclear relaxation behavior is well described in terms of the self-consistent renomalized (SCR) spin fluctuation theory for nearly AF metals, whereas below T sf a deviation is significant and 1/T 1 T exhibits a weak T variation. It is pointed out that T sf coincides with the temperature below which a T 2 law in electrical resistivity is valid as expected for a Fermi liquid ground state. We proposed that these features are understood from the standpoint that the development of AF spin fluctuation remains in short-range associated with the singlet formation among Mn spins in each tetrahedron as suggested by the inelastic neutron experiments on Y 1−x Sc x Mn 2 .

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Effect of Lead-doping on the Transport Properties of BiSrCaCuO

Erratum: Pressure-dependent electrical resistivity of R Co 2 compounds ( R =rare earth) [Phys. Rev. B 57 , 2904 (1998)]

Physical Review B

Field and pressure dependence of itinerant electrons metamagnetism in Er 1− x Y x Co 2 1 Originally accepted for publication in the Proceedings of ICM'97 but not included therein by the Conference ruling on presentation. 1

ABSTRACT

$Research paper thumbnail of Decoupling of the magnetic ordering of the rare-earth and the Co sublattice in Er_ {1-x} Y_ {x} Co_ {2} compounds driven by substitution or pressure$

Decoupling of the magnetic ordering of the rare-earth and the Co sublattice in Er_ {1-x} Y_ {x} Co_ {2} compounds driven by substitution or pressure

Physical Review B

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Inverse itinerant electron metamagnetism in ErTxCo2, T=Y, Tm

Fuel and Energy Abstracts

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Pressure dependent electrical resistivity of Cu2O-TCNQ

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Onset of magnetic order in YbCu5 _xMx

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$Research paper thumbnail of Superconducting properties of La_ {3} Ni_ {2} B_ {2} N_ {3-δ}$

Superconducting properties of La_ {3} Ni_ {2} B_ {2} N_ {3-δ}

Nearly-single-phase La3Ni2B2N3-δ prepared by arc melting and subsequent annealing at 1100 °C is c... more Nearly-single-phase La3Ni2B2N3-δ prepared by arc melting and subsequent annealing at 1100 °C is characterized by x-ray powder techniques, electron microprobe analysis, and high-resolution electron microscopy. A standardized set is provided for the crystallographic parameters, and structural chemistry is described from the point of view of nonmetal-nonmetal interactions as well as of the metal coordination around the nonmetal atoms. The superconducting properties of La3Ni2B2N3-δ are studied by means of resistivity, magnetization, and heat capacity measurements. The obtained critical fields μ0Hc(0)=0.16 T, μ0Hc1(0)=13(2) mT, and μ0Hc2(0)=7.5(5) T classify La3Ni2B2N3-δ as a hard type-II superconductor with a Ginzburg-Landau parameter κ=33(2), a coherence length ξ0=7.0(5) nm, and a penetration depth λ(0) of about 210 nm. The pressure dependence of Tc with dTc/dp=-130 mK/kbar is found to be one order of magnitude larger than for RNi2B2C (R=Y, Lu). Since the deviations of the thermodynami...

Volume dependence of the physical behaviour of YbCu5−xAgx

Physica B: Condensed Matter, 1997

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Pressure and Field Dependence of the Resistivity in Reco 2 Compounds

International Journal of Modern Physics B, 1993

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Non-fermi liquid behavior in the system Ce(Rh/sub 1-x/Ru/sub x/)/sub 3/B/sub 2/

7th Joint MMM-Intermag Conference. Abstracts (Cat. No.98CH36275), 1998

Heavy-fermion characteristics in UCu 5 Al single crystals

Physical Review B, 2002

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Superconducting properties of La3Ni2B2N3- delta

Physical review. B, Condensed matter, 1996

Nearly-single-phase La3Ni2B2N3-delta prepared by arc melting and subsequent annealing at 1100 °C ... more Nearly-single-phase La3Ni2B2N3-delta prepared by arc melting and subsequent annealing at 1100 °C is characterized by x-ray powder techniques, electron microprobe analysis, and high-resolution electron microscopy. A standardized set is provided for the crystallographic parameters, and structural chemistry is described from the point of view of nonmetal-nonmetal interactions as well as of the metal coordination around the nonmetal atoms. The superconducting

Pressure dependence of the magnetic order in RMn2 (R=rare earth)

Physical review. B, Condensed matter, 1994

... transitions are thermodynamically related, the first-order transition associated with the mag... more

Onset of magnetic order in YbCu5-xAlx

Physical Review B, 1997

ABSTRACT

Thermodynamic properties of Ce(RuxRh1−x)3B2

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Robert Hauser

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