Dust particles of sizes between 1 micron and 100 microns from various materials have been contained with help of quadrupole field in vacuum chamber at pressures from 10^-4 to 10^-6 mbar and charged by Ar^+ ions of energies up to 3 keV as well as by electrons of energies up to 5 keV. For damping of particles motion at low
pressures the damping system with photomultipliers and feedback circuits was developed. By charging with Ar^+ ions charge-to-mass ratios up to 4 C kg^-1 were measured and dependence of maximum charge-to-mass ratio on the energy of ions was studied. Measurements of parameters of secondary electron emission by charging with electrons at different chamber pressures were started.
Detectors like the IPCS and CCD make it possible to study strong velocity gradients at high spatial resolution even in the presence of large intensity gradients. Strong velocity gradients indicating galactic shocks have been found in NGC 1365 at the inner side of a spiral arm, at the leading edges of the bar, and in the nuclear region. The shocks in the nuclear region are suggested to be caused by rapid twisting of closed orbits at the position of the ILR.
A photometric membership test has been carrled out for stars in the region of the open cluster M 39 (= NGC 7092 = OCL 211 = C 2130 + 482) selected by ARTIUKHINA, KALININA from proper motions to be probable members of the cluster corona. Using own UBV observations of 28 brighter (BD) stars and additional photometric data from other available sources out of the 117 probable members in the region outside of the cluster core altogether for 37 the membership could be confirmed. 22 of the stars do not belong to the cluster. The results confirm the existence of the cluster corona found statistically by ARTIUKHINA. The distribution of the confirmed members over the investigated area of about 5' diameter indicate that the corona of this poor cluster is much more extended than 75' as suggested by the statistical investigation.
Some comments on problems connected with our knowledge and understanding of events observable during the meteoroid flight through the atmosphere are presented. The review is divided into
three parts. Tbe first part deals with the section of flight characterized by the increase of body temperature from the value reached at the heliocentric distance 1 AU, i.c. at the frontier of the Earth´s atmosphere, which was estimated to be approximatelly 280° K, to the temperature at which the evaporation of the meteoroid can start. This process is designated as pre-ablation heatlng. The second part deals with efects connected with the visible trajectory as well as with ionization trails and problems related to them. There exists generic connection between luminous flight of meteoroids and dark flight with possibility of finding the meteorites fallen to the ground namely with the predictabllity of the impact area and the impact itself. This is the subject of the third part.
Quasi Stationary Spiral Structure is the natural Interpretation for grand deqlgn spiral galaxies. The best theoretical tool to descrlbe QSSS morphologles is the study of spiral modes. Modal studies are characterlzed by two distinct stages. At the dynamical level, one wishes to compute spiral modes efflcently on a variety of equilibrium models and to master the relation between the properties of the basic states and the propertles of the relevant spiral modes. At the astrophysical level, realistic basic states are identified by dlscussing the processes of evolutlon and
self-regulatlon; in partlcular, we Identify some basic states conslstent wlth QSSS grand designs and others where more flocculent spiral structure is expected to occur. For thls second stage It is cruclal to have a proper interpretation of the results obtained from one-component models In vlew of the multiple component astrophysical systems to be described (which include stars, Population 1 objects, and cold gas). Followlng this outllne, under the guidance of a slmple analytlc (asymptotic) theory, a very large set of galaxy models has been studled numerically. Thls is essentlally a three dimensional survey wlthln a flexlble class of models, where one parameter measures the amount of partlclpatlng disk mass, a second parameter determlnes the
hotness of the disk and the third is a scale length which combines propertles of the slze of the nuclear bulge and the dlstrlbutlon of the cold gas component. All the essentlal morphologlcal types found in the Hubble diagram have been reproduced; in partlcular, parameter reglmes are identified for SA and SB galaxies and speclfically for SBO, SB-r and SB-s objects. Dlstinction is made between systems where gas is expected to play an actlve or a passlve role.
Time and latitude observations, made by the circumzenithal at the Geodetical Observatory Pecný (Ondřejov) in the years 1970-1983, were analysed and some secular and periodical terms were proved. These results are studied from the standpoint of possibilities of their geodynamical interpretation: determination of the secular variation of the station position, detection of the secular, Chandler's and annual polar motion from optical measurements at the single station, and tidal influence on the variation of the local plumb-line.
Cometary dust grains as measured by the Halley space missions show a silicate- and a light element component. The latter most likely represents an organic material. The densities of the grains are mostly below 1 g/cm^2. The organic component slowly decays at higher temperatures during subsequent perihelion passages. Therefore the "older” cometary grains are different from the "young" cometary grains: they show higher albedos, higher densities and orbit finally within the inner solar system.
Thls review emphasizes the great deal of work devoted in the past 15 years to the construction of formal theories of the motion of resonant satellites. The importance of formal theories and they fundamental concepts are also discussed. We consider the kernels derived by Jefferys and Ries, Sessin and Hori for the construction of formal theories for mutually perturbing satellites.
Some recent results concerning the determinations of the parameters of libration of several systems as well as the accelerations of the Galilean satellites and of Mlmas are also presented.