Interplanetary magnetic field and geomagnetic Dst variations     

V. L. Patel  U. D. Desai 《Astrophysics and Space Science》1973,20(2):431-437

The interplanetary magnetic field has been shown to influence the ring current field represented by Dst. Explorer 28 hourly magnetic field observations have been used with the hourly Dst values. The moderate geomagnetic storms of 60 and quiet-time fluctuations of 10–30 are correlated with the North to South change of the interplanetary field component perpendicular to the ecliptic. This change in the interplanetary field occurs one to three hours earlier than the corresponding change in the Dst field.  相似文献   

Neuere Veröffentlichungen     

F. Model  M. Tomczak Jr.  U. Charisius 《Ocean Dynamics》1966,19(4):177-180

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Multidirectional scanning of active regions with a slit-jaw spectrograph and a solar chromatograph     

U. Kusoffsky  G. Pålsgård 《Solar physics》1973,30(1):121-127

At the Swedish Solar Observatory in Anacapri we have simultaneously used the following combination of instruments in our investigation of active regions:

1. A spectrograph with an image rotator placed in front of the slit.
2. A subtractive double dispersive spectrograph (solar Chromatograph).
3. A Hα+0.5 Å patrol instrument. Scans over the 3b flare of August 4th 1972 are used to illustrate the method. The illustrations clearly show downflowing matter connected with bright knots and filaments in the emitting area, possibly in accordance with Hyder's infall-impact mechanism.

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Observation of solar particle fluxes over extended solar longitudes     

R. P. Bukata  U. R. Rao  K. G. McCracken  E. P. Keath 《Solar physics》1972,26(1):229-240

Detailed particle observations from various Pioneer Spacecrafts located at different heliolongitudes during the complex solar flare events of March 30–April 10, 1969 have been utilised to investigate the energy dependence of azimuthal gradients of cosmic ray particles and its effect on the decay of the flare intensity. For an observer located to the east of the centroid of the population, the azimuthal corotation term and the convection term will be additive, resulting in a short decay time constant. An observer located to the west of the centroid of the population will experience a much longer decay time constant, the corotation term partially or completely compensating the loss of particles due to convection. At very low energies, the azimuthal corotation term may even be more than the convection term, thus resulting in a rise in intensity instead of decay during late in the event. Using the relationship showing the dependence of the spectral exponent of the cosmic ray flux late in a flare event on the azimuth from the centroid of the population given by McCracken et al., the energy dependence of the decay time constant and the cross-over energy at which the azimuthal gradient term equals the convection term are investigated. The experimental observations are shown to be generally consistent with the theoretical picture, confirming the importance of convection and the azimuthal gradient in determining the decay profile of flare events.On leave from Physical Research Laboratory, Ahmedabad, India.Now at CSIRO, G.P.O. Box 136, North Ryde, N.S.W., Australia.  相似文献   

RECENT DEVELOPMENTS IN MULTIVARIATE CALIBRATION   总被引：1，自引：0，他引：1  

B.R.KOWALSKI M.B.SEASHOLTZ Laboratory for Chemometrics  BG-  University of Washington  Seattle  WA  U.S.A. 《地理学报(英文版)》1991,(3)

With the goal of understanding global chemical processes,environmental chemists have some of the mostcomplex sample analysis problems.Multivariate calibration is a tool that can be applied successfully inmany situations where traditional univariate analyses cannot.The purpose of this paper is to reviewmultivariate calibration,with an emphasis being placed on the developments in recent years.The inverseand classical models are discussed briefly,with the main emphasis on the biased calibration methods.Principal component regression(PCR)and partial least squares(PLS)are discussed,along with methodsfor quantitative and qualitative validation of the calibration models.Non-linear PCR,non-linear PLSand locally weighted regression are presented as calibration methods for non-linear data.Finally,calibration techniques using a matrix of data per sample(second-order calibration)are discussed briefly.  相似文献   

ESTIMATION OF ERRORS IN ABSORBANCE RATIO MEASUREMENTS     

MUHAMMAD SHARAF GARY ARROY RON PERKINS Spectra-Physics Inc.  North First Street  San Jose  CA  U.S.A. 《地理学报(英文版)》1991,(3)

Ratio measurements are commonly used to address a variety of analytical problems in environmental,forensic and pharmaceutical laboratories.In absorbance ratioing techniques,analytical chemists rely onthe spectral features of the analyte(s)of interest.The absorbances at two wavelengths are monitored andthe ratio of these two absorbances is computed.This ratio is then used to confirm the identity of theanalyte(s)of interest,the purity of a product or the overlap of chromatographic peaks.These decisionsoften have far-reaching consequences(e.g.the identification of the source,biogenic or petrogenic,ofhydrocarbons in biological tissues or water).Given the cost and the liabilities associated with suchdecisions,it is unfortunate that these ratios are seldom reported with any statistical confidence.Thepurpose of this study is to delineate the parameters that affect absorbance ratio measurements.Themodels that can be used to estimate the statistical confidence in these measurements are derived andevaluated experimentally.The results show that these models can estimate the relative standard deviationsin absorbance ratios accurately.They can also estimate the effect of signal-to-noise ratio and the choiceof wavelengths on the precision of absorbance ratios.  相似文献   

Spectrophotometry of comet West (1975n) after the perihelion passage     

U. S. Chaubey 《Astrophysics and Space Science》1978,54(1):233-237

In the wavelength range 350 to 650 nm, the flux distribution of comet West (1975n) is presented for various dates following perihelion passage. The variations with heliocentric distance, in the flux of the emission features of the CN band at 388 nm, the C₂ bands at 474 nm, 516 nm and 563 nm and Na at 589 nm, have been discussed. It is concluded that the comet was dust rich.  相似文献   

Neuere Veröffentlichungen     

U. Charisius  H. Seilkopf  G. Heise 《Ocean Dynamics》1967,20(1):26-28

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Theory and operation of the split langmuir probe     

E.A. Bering  M.C. Kelley  F.S. Mozer  U.V. Fahleson 《Planetary and Space Science》1973,21(11):1983-2001

An instrument, the split Langmuir probe, has been developed to make in situ measurements of current density and plasma bulk flow. The split Langmuir probe consists of two conducting elements that are separated by a thin insulator that shield each other over a 2π solid angle, and that are simultaneously swept from negative to positive potentials with respect to the plasma. By measuring the current to each plate and the difference current between plates, information can be obtained on the plasma's current density, bulk flow, electron temperature, and density. The instrument was successfully test flown from Fort Churchill on 2 August 1968, with results in reasonable agreement with those from another experiment on the same rocket. Sources of error indicated by these results include plate area differences, plate work function differences, input resistor differences, and probe wake effects. The error signal in the difference current data due to plate work function differences rose to a sharp maximum at plasma potential, which served the useful purpose of precisely marking plasma potential. Possible changes in probe geometry, sweep rate, and telemetry designed to reduce these errors are discussed.  相似文献   

II Vulcano Cimino     

U. Ventriglia 《Bulletin of Volcanology》1963,25(1):183-199

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