field measurement of transverse diffusion in unidirectional flow in a wide, straight channel

a knowledge of the magnitude of the transverse diffusion coefficient for open channel flow is of importance in water quality studies of rivers and estuaries. measurements of the coefficients have been made in a straight reach of an urban stream. rhodamine wt was used as the tracer and good dye recovery ratios and data reproducibility were..

instrument to measure wave numbers of cw and pulsed laser lines' the sigmameter

reports the first absolute wave number measurements made using a sophisticated version of the sigmameter. this apparatus is composed of four double michelson type interferometers with fixed path differences. all path differences are calibrated using four reference lines given by single-mode lasers stabilized on iodine lines whose absolute..

cleaning and maintenance of the computer

one british company supplying approved products for service and maintenance to major hardware manufacturers has developed a complete range of manufacturer-approved products with the small system user specifically in mind. included in the programme is a computer care kit in book form, containing all the products necessary for the d.p and w..

influence of the earth magnetic field of the photoionization stark spectrum of excited sodium atoms

the authors performed an experiment on sodium atoms in a well controlled m/sub l/ state. more precisely the experiment has been done on the sodium atoms of an atomic beam which are submitted to two laser excitations in the presence of a dc electric field. the first laser excitation is provided by a cw single mode dye laser right-hand pola..

direct observation of hot-electron spectra from laser-excited sodium vapor

a sodium atomic beam with density 10/sup 13/ cm/sup -3/ was illuminated by cw dye laser radiation (a few watts per square centimeter) tuned to the d/sub 2/ resonance line. in the energy spectrum of the emitted electrons, several lines were observed between 4 and 7 ev. their positions and intensities indicate that seed electrons are produc..

absolute determination of the wavelengths of the sodium d/sub 1/ and d/sub 2/ lines by using a cw tunable dye laser stabilized on iodine

coincidences between the sodium d/sub 1/ d/sub 2/ lines and two corresponding /sup 127/i/sub 2/ lines have permitted the determination of the absolute wavelengths of the hyperfine components of the sodium d lines by using a cw tunable dye laser the laser frequency, locked in turn on the 'o' and 'n' hyperfine compounds of the p 114 and (14..

laser investigation of odd krypton rydberg levels using the field ionisation detection method

a two-step optical excitation, starting from a metastable level, has been used to populate rydberg levels in a krypton atomic beam. the metastable level is populated in the beam 'oven' by means of a hf discharge and the rydberg atoms are detected by the field ionisation method. using two n/sub 2/-pumped pulsed dye lasers, the rydberg spec..

new laser-induced fluorescence fourier transform spectrometry' the /sup 7/li/sub 2/ ground-state dissociation limit

the use for the first time of a high-resolution fourier transform spectrometer to analyse the laser-induced fluorescence from a ring dye laser allows observation of vibrational levels of the /sup 7/li/sub 2/ molecule close to the ground-state dissociation limit. this extends the known potential curve from 5.18 aa (88percent of the dissoci..

double-minimum (2)/sup 1/sigma/sub u//sup +/ state of na/sub 2/

a new double-minimum state, (2)/sup 1/sigma/sub u//sup +/, of na/sub 2/ has been characterized by infrared fluorescence recorded at high resolution by fourier-transform spectrometry. a ring dye laser populates /sup 1/sigma/sub g//sup +/ rydberg levels in the two-photon process /sup 1/sigma/sub g//sup +/=a/sup 1/sigma/sub u//sup +/=x/sup 1..

two methods for nuclear spin determination in collinear laser spectroscopy' classical rf magnetic resonance and observation of the larmor precession

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