Chair of solid state physics . ... The Physics of Phonons . ... In the first part of the course “The Physics of Phonons” the dynamics of atoms in one- and three- dimensional crystalline lattices is considered in detail. The quasiparticle conception in solids, taking phonons as an example, is discussed; creation and annihilation operators of phonons, main properties of acoustic and optical phonons dispersion laws, density of phonon states. ... Crystalline state. ... Acoustic and optical phonons. ...

... The procedure of radiometer signal integration can be considered as a sort of reducing dimension of the initial sampling space, where the samples are the result of analog-to-digital conversion. ... The probability distribution of the signal and spikes is completely known. ... The quality of the considered algorithm could be also illustrated by Figure 2 . ... One could see the considered adaptive algorithm is preferable even by low degree of compression, because all spikes have been depressed. ...

... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . ... Open symbols refer to data available in the literature. ... The best-fit lines correspond to the exponential-linear relation discussed in Sect. ... We present a new extensive analysis of the old problem of finding a satisfactory calibra- tion of the relation between the geometric albedo and some measurable polarization properties of the asteroids. To achieve our goals, we use all polarimetric data at our disposal. ...

... Clearing the library. Note the different flooтАж . Sidebar Left . Sidebar Top . ... Title: Clearing the library. Note the different floor levels. There were at least 4 different levels of underfloor in the library. Description: NOTE: All images and movies are copyright and must not be reproduced or mirrored in any form without written permission. ... NOTE: All images and movies are copyright and must not be reproduced or mirrored in any form without written permission. ...

Astronomy Picture of the Day . ... 13.06.2005 . ... Last June in Kansas , storm chaser Eric Nguyen photographed this budding twister in a different light -- the light of a rainbow . Pictured above , a white tornado cloud descends from a dark storm cloud. ... By coincidence, the tornado appears to end right over the rainbow . ... Over 1,000 tornadoes, the most violent type of storm known, occur on Earth every year, many in tornado alley . ... NASA Web Site Statements, Warnings, and Disclaimers . ...

The ion rocket is another means of providing thrust, more gradually but also more efficiently than a conventional rocket. ... As in the nuclear rocket, the energy which propels the xenon jet comes from a different source; here it is electrical energy from solar cells. The reason an ion rocket is much more efficient than ordinary rockets is the way its jet is produced. ... As with solar sails, solar ion engines are mainly practical in the inner solar system, where ample sunlight is available. ...

Distribution of the analyzed SEPs with different >100 MeV proton fluxes ( J 100 ) at the microwave flux density plane ' S 9 vs. ... 1) General correspondence takes place between intensities of microwave bursts and proton fluxes - J 100 increases when S 9 and S 15 rise. ... 3) Powerful microwave bursts ( S 9 , S 15 >3000-10000 sfu ) with hard radio spectra ( S 9 < S 15 ) correspond to majority of powerful proton fluxes ( J 100 >10 pfu ). ...

Authors: Yu.G. Shevelev , V.A. Marsakov , . ... We have constructed and investigated properties of metallicity function of disk stars with different ages, proceeding from the statistically restored real altitude distributions of stars at the solar galactocentric distance. It is shown that the metallicity distribution of stars in each age range is not of Gaussian form, but it may be considered as a superposition of two normal distributions centered at -0.2 and 0.0 dex. ...

. There are several different shells available for Unix; the most popular are described here. You can use any one of these shells if they are available on your system. And you can switch between the different shells once you have found out if they are available. Bourne shell (sh) . C shell (csh) . TC shell (tcsh) . Korn shell (ksh) . Bourne Again SHell (bash) .

... Between them, the following points are touched: ICRF-2 structure, ICRF Core sources selection, and some expected user's requirements. ... Suggested total number of sources is close to the number of sources already observed in the IVS and VCS sessions, and for most of them reliable positions are derived, mostly for declination > -40 deg. ... So, results of source position time series analysis heavily depend on method used for time series computation and should be used with care. ...

... 18-Jan-2010 17:22 . ... Apache/2.2.3 (CentOS) Server at www.wdcb.ru Port 80 ...

This module provides the ability to set environment variables based upon attributes of the request. ... The mod_setenvif module allows you to set environment variables according to whether different aspects of the request match regular expressions you specify. ... BrowserMatch . ... Syntax: BrowserMatch regex env-variable [= value ] [ env-variable [= value ]] .. ... Module: mod_setenvif . ... The BrowserMatch directive defines environment variables based on the User-Agent HTTP request header field. ...

... The orbit of this fragment H is considered as that of the maternal body. ... We have estimated the diameters of the maternal body for the different moments of disintegration. ... The 182 computations show that the maternal body of the nucleus was of 1.24 km in diameter, if its disintegration happened at the closest approach of the comet to Jupiter, and of 9.73 km, if the nucleus had been disintegrated two hours before the moment of approach. ...

M1 image More About M1 Nice Color Picture . ... M16 image More About M16 HST image . ... M31 image More About M31 Nice Color Picture . ... M42 image ; M43 image More About M42/43 Nice Color CCD Picture . M51 image More About M51 Color Image of M51 M51 Supernova . M57 image More About M57 Nice Color CCD Picture Very Deep M57 Image . ... M81 image More About M81 M81 Supernova Ultraviolet Image of M81 More about Ultraviolet Imaging . M82 image More About M82 M82 False Color M82 True Color . ...

... Space flight . Crew training . ... The contemporary world opinion, while welcoming the efforts of different states aimed at realization of manned space flights, still considers these efforts insufficient, over-bureaucratized and too slow. ... The more up-to-date is the basic training program for a cosmonaut/astronaut or a manned space flight participant (hereinafter referred to as the student) that is being offered to your interested attention. ... Pre-flight space training (PFST). ...

... Information about a variety of different calendars for different cultures (e.g., Christian, Jewish, Muslim, Chinese, Hindu etc.) ... In addition, the Chinese had two different ways of interpreting and observing celestial events. One way the Chinese used astronomy was known as lifa; it was a discipline that aimed to understand the regularities and the predictable events in the celestial system through careful, observations, measurements and records. ... back to Teachers' Newsletter Main Page ...

Blackholes Forum Message . Forums: . Atm ћ Astrophotography ћ Blackholes ћ Blackholes2 ћ CCD ћ Celestron ћ Domes ћ Education . ... Discussion Forums | Blackholes I | ... There Are Two Different Situations Here! Forum List | ... Back to Thread Topics | ... www.astronomy.net . About Astronomy Net | Advertise on Astronomy Net | ... Forum posts are Copyright their authors as specified in the heading above the post. "dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET" . ...

... stars . ... Could gas giants be considered stars that failed to ignite? ... The distinction between gas giant planets and brown dwarfs ("failed stars") is a vague one. ... It depends on what gas giant youт??re looking at and how you distinguish a т??planetт?? from a т??failed star.т?? A gas giant found in orbit around a star might be considered a planet like Jupiter around the Sun. An isolated gas giant is probably a failed star. ... Get instant access to subscriber content on Astronomy.com! ...

The preliminary version of documentation of the format for the interchange of calibrated optical/IR data being developed by Tom Pauls of NRL and John Young of COAST was presented and a number of issues discussed. The proposed format is in the general form of a relational database with different components stored in FITS binary tables. ... Should there be a single data table type that includes all data types, or multiple table types, one per data type? What data types are needed? ...

... Dale A. Gardner . NASA Astronaut (deceased) . ... NASA EXPERIENCE: б  Gardner was selected as an Astronaut Candidate by NASA in January 1978, reporting to the Johnson Space Center in July 1978.б  In August 1979, he completed a one-year training and evaluation period, making him eligible for assignment as a mission specialist astronaut .б  He subsequently served as the Astronaut Project Manager for the flight software in the shuttle onboard computers leading up to the first ...