ZfN: Search Results

1	Author	J. L. Schiano, A. J. Blauch, M. D. Ginsberg	Requires cookie*
	Title	Optimization of NQR Pulse Parameters using Feedback Control
	Abstract	A new method for increasing the probability of detecting nuclear resonance signals is demon-strated experimentally. It is well known that the detection of signals with a low signal to noise ratio (SNR) results in missed detections of false alarms. In situations where the noise is correlated or where limited data is averaging, it may not be possible to achieve a desired SNR through averaging alone. We present an alternative approach in which a feedback algorithm automatically adjusts pulse parameters so that the SNR and probability of correct detection are increased. Experimental results are presented for the detection of 14 N NQR signals.
	Reference	Z. Naturforsch. 55a, 67—73 (2000); received August 28 1999
	Published	2000
	Keywords	Nuclear Quadrupole Resonance, Feedback Control, Receiver Operating Characteristics
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	TEI-XML for	default:Reihe_A/55/ZNA-2000-55a-0067.pdf
	Identifier	ZNA-2000-55a-0067
	Volume	55

2	Author	J. L. Schiano, M. D. Ginsberg	Requires cookie*
	Title	A Pulsed Spectrometer Designed for Feedback NQR
	Abstract	A pulsed NQR spectrometer specifically designed to facilitate real-time tuning of pulse sequence parameters is described. A modular approach based on the interconnection of several rack-mounted blocks provides easy access to all spectrometer signals and simplifies the task of modifying the spectrometer design. We also present experimental data that demonstrates the ability of the spectrometer to increase the signal to noise ratio of NQR measurements by automatically adjusting the pulse width in the strong off-resonant comb pulse sequence.
	Reference	Z. Naturforsch. 55a, 61—66 (2000); received August 28 1999
	Published	2000
	Keywords	Nuclear Quadrupole Resonance, Spectrometer Design, Real-time Programmable Pulse Sequence Generator
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	TEI-XML for	default:Reihe_A/55/ZNA-2000-55a-0061.pdf
	Identifier	ZNA-2000-55a-0061
	Volume	55

3	Author	P. F. Meier, T. A. Claxton, P. Hüsser, S. Plibersek, E. P. Stoll	Requires cookie*
	Title	Cluster Calculations of Hyperfine Interactions in Superconducting Copper Compounds
	Abstract	This paper discusses first-principles cluster investigations on the electronic structure of YBa2Cu3Ü7 and La2CuC>4 performed at the University of Zürich. In particular, electric field gradients have been calculated at the copper sites and their dependence on applying uniaxial strain is studied. Magnetic hyperfine interactions have been evaluated from spin-polarized calculations, and the transfer of spin density from neighboring copper ions is explained. An interpretation is given of the nuclear quadrupole resonance spectra in doped La2CuC>4.
	Reference	Z. Naturforsch. 55a, 247—255 (2000); received August 26 1999
	Published	2000
	Keywords	Cluster Calculations, Electric Field Gradients, High-Temperature Superconductors, Hyperfine Fields, Nuclear Quadrupole Resonance
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	TEI-XML for	default:Reihe_A/55/ZNA-2000-55a-0247.pdf
	Identifier	ZNA-2000-55a-0247
	Volume	55