Literal solution for Hill's lunar problem     

Dieter S. Schmidt 《Celestial Mechanics and Dynamical Astronomy》1979,19(3):279-289

A computer program for the manipulation of power series in several variables is used to find the first order solution to Hill's lunar problem. The ratiom of the mean motion of the Sun to that of the Moon is kept as a formal parameter. The series inm are known to converge very poorly. It is shown how efficient algorithms among them the Lie transformation allow us to compute the series inm as far as they are needed. When the series are evaluated at Brown's numerical value form the results achieve or exceed his accuracy.  相似文献   

Announcement     

Wolfgang Cramer  Uta Fritsch  Rik Leemans  Sabine Lütkemeier  Dagmar Schr?ter  et al. 《Journal of Paleolimnology》1989,2(4):319-320

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Mercos — A simple Teflon sampler for ultratrace metal analysis in seawater     

Peter Freimann  Diether Schmidt  Karl Schomaker 《Marine Chemistry》1983,14(1):43-48

This paper describes an uncomplicated sampling technique for ultratrace element analysis of coastal and surface seawaters (maximum depth 100 m). The sampler system is very easy to operate. To prevent contamination problems, interchangeable 500-ml Teflon bottles are used as both sampling and storage vessels. The seawater samples are stabilized in situ by preacidifying the sampling bottles. For the determination of mercury in seawater the desired system has been developed: sampling bottle = storage bottle = reaction vessel.  相似文献   

The stability of the Lagrangian point L4     

D. S. Schmidt 《Celestial Mechanics and Dynamical Astronomy》1988,45(1-3):201-206

The Hamiltonian function of the restricted problem of three bodies near the triangular Lagrangian point is normalized through sixth order terms with the help of MACSYMA. The same calculations were done previously with an algebraic processor in order to establish the stability at a critical value of the mass ratio.  相似文献   

THE KRAMER CREEK,COLORADO METEORITE: A NEW L4 CHONDRITE     

Everett K. Gibson  David E. Lange  Klaus Keil  Terry E. Schmidt  J. Michael Rhodes 《Meteoritics & planetary science》1977,12(2):95-107

The Kramer Creek, Colorado, chondrite was found in 1966 and identified as a meteorite in 1972. Bulk chemical analysis, particularly the total iron content (20.36%) and the ratio of Fe_total/SiO₂ (0.52), as well as the compositions of olivine (Fa_21.7) and orthopyroxene (Fs_18.3) place the meteorite into the L-group of chondrites. The well-defined chondritic texture of the meteorite, the presence of igneous glass in the chondrules and of low-Ca clinopyroxene, as well as the slight variations in FeO contents of olivine (2.4% MD) and orthopyroxene (5.6% MD) indicate that the chondrite belongs to the type 4 petrologic class.  相似文献   

Rms-value and power spectrum of the photospheric intensity-fluctuations     

W. Schmidt  M. Knölker  E. H. Schröter 《Solar physics》1981,73(2):217-231

The power spectrum and the rms-value of the granular intensity fluctuations were studied using granulation photographs of excellent quality obtained during the JOSO site testing campaign 1979 at Izaña. The observed power spectrum was corrected using various effective modulation transfer functions of the system: telescope+aberrations+atmospheric seeing, assuming different contributions of the atmospheric seeing. With this procedure a lower and upper limit for the ‘true’ power spectrum of the granular intensity fluctuations and thus for the rms-value could be derived: 7.2% <I _rms <12% at λ = 550 nm, with a most probable value of I _rms = 10.5%. We checked the validity of the upper limit by applying to our data a MTF (Deubner and Mattig, 1975), which certainly must lead to an overcorrection. This procedure lead to I _rms = 13.4%. Thus we can state that the true rms-value of the granular intensity fluctuations does certainly not exceed 13% at λ = 550 nm.  相似文献   

Preface     

Jean Chapront  Jacques Henrard  Dieter Schmidt 《Celestial Mechanics and Dynamical Astronomy》1982,26(1):2-3

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Existence and amount of intergalactic dust     

K. -H. Schmidt 《Astrophysics and Space Science》1975,34(1):23-31

The existence of intergalactic dust has been proved by the following observational facts: the decrease of the numbers of distant galaxies and clusters of galaxies behind the central regions of near clusters of galaxies; the different distributions of RR Lyrae stars and galaxies near ι Microscopii (Hoffmeister's cloud); the dependence of colour excesses of galaxies on supergalactic coordinates as well as on the surface density of bright galaxies; the colour index vs redshift correlation of quasistellar objects. The densities of intergalactic dust are estimated to be between 5×10^?30 g cm^?3 (near the centers of clusters of galaxies) and 2×10^?34 g cm^?3 (in general intergalactic space). The grains may be formed either in the early phases of the Universe (25相似文献   

The interaction of the solar wind with a comet     

L. Biermann  B. Brosowski  H. U. Schmidt 《Solar physics》1967,1(2):254-284

The flow of plasma on the sunward side of a comet is investigated by means of an axialsymmetric model based on hydrodynamics modified by source terms. The model assumes a given curvature of the isobaric surfaces, which corresponds to paraboloids around the nucleus of the comet. The flow on the axis can be represented by a solution of a system of seven ordinary differential equations (respectively five in case of pure photo-ionization). The flow pattern always contains a widely detached bow shock and a contact discontinuity separating a cavity with purely cometary plasma from the transition region containing also solar wind ions. The model is applied to the special case where the cometary gas is ionized by the solar UV radiation only. Numerical solutions are integrated for five levels of production of neutral gas by the comet and for seven typical situations in the undisturbed solar wind. The results imply standoff distances of the stagnation point from the nucleus of the order of 10 000 km or more, and distances of the bow shock of the order of 10⁶–10⁷ km.  相似文献   

Detection of PAHs in seawater using surface-enhanced Raman scattering (SERS)     

Schmidt H  Bich Ha N  Pfannkuche J  Amann H  Kronfeldt HD  Kowalewska G 《Marine pollution bulletin》2004,49(3):229-234

The laboratory characterization of a field-operable surface-enhanced Raman scattering sensor (SERS optode) is presented for the detection of aromatic hydrocarbons in seawater. The sensor has been developed for deployment with a robust underwater spectrograph. To meet the demands of the harsh seawater application, sol-gel derived SERS substrates were used. The calibration curves of six PAHs were determined to be of Langmuir adsorption isotherm type with limits of detection ranging from the microg l(-1) to ng l(-1) level. The experimentally determined adsorption constants varied strongly with the molecular weight of the analytes and correlated with their solubility. A mixture of five PAHs dissolved in seawater was investigated to demonstrate the utility of this method for screening. Emphasis was put on the interference from suspended particulate matter (SPM). The Raman measurement with backscattering configuration was shown to be immune against turbidities up to 1000 NTU. The physico-chemical interference arising from adsorption by the sediment was measured on-line by adding sediment to a PAH-spiked solution. According to the calibration curve, the PAH concentration decrease corresponded to more than 98% of the analyte being scavenged by the sediment.  相似文献