606 research outputs found
Radio Detection of 18 Rass BL Lac Objects
We present the radio detection of 18 BL Lac objects from our survey of over
575 square degrees of sky. These 18 objects are located within 20 arcsec of the
X-ray position, of which 11 have a measured red-shift. All candidates are radio
emitters above ~1 mJy and fall within the range of existing samples on the two
colour, alpha_ro vs alpha_ox, diagram with a transitional population of three
(3) evident. Two unusual sources have been identified, a candidate radio quiet
BL Lac, RX J0140.9-4130, and an extreme HBL, RX J0109.9-4020, with
Log(nu_peak)~19.2. The BL Lac Log(N)-Log(S) relation is consistent with other
samples and indicates the ROSAT All Sky Survey (RASS) could contain (2000+-400)
BL Lac objects.Comment: 14 pages, 6 figures, accepted for publication in Serbian Astronomical
Journa
Polarographic Determination of Stability Constants of Glycerato Complexes of Cadmium and Lead
Stability constants of glycerato complexes of cadmium and
lead were determined by the polarographic method. Measurements
were performed in buffer solutions of sod1um salt of DL-glyceDic
acid. The concentration of the glyceric aoid in the buffer solutions
was constant: 0.0 7 M for cadmium, and 0.05 NI for lead. The ionic
strenght of solutions was 2 and -it was kept constant by m e ans of
sodium perchlorate . The following cumulative stability constants
were obta;ined: Cadmium: Bi = 40, B2 = 130, B3 = 340, B = 2.10.
Lead: [3 1 = 340, B2 = 5.7 X 10 3, Ba = 2.8 X 10 3, B4 = 4.8 X 10 3
On the Stability Constants of Copper(II) Formato, Acetato, Propionato, Butyrato and Glycolato Complexes Determined by the Spectrophotometric Method
In an earlier paper1 the stability constants of Oo(II), Ni(II), Zn(II), Cd(II)
and Pb(II) formato, acetato, propionato, butyrato, glycolato and chloroacetato complexes, determined by potentiometric1, polarographic~ , 3 and spectrophotometric4 methods, were summarfaed. Good agreement between stability constants determined by different methods were obtained, except for the complexes specified ~n the title, which were examined spectrophotometrically and polarographically
On the Stability Constants of Copper(II) Formato, Acetato, Propionato, Butyrato and Glycolato Complexes Determined by the Spectrophotometric Method
In an earlier paper1 the stability constants of Oo(II), Ni(II), Zn(II), Cd(II)
and Pb(II) formato, acetato, propionato, butyrato, glycolato and chloroacetato complexes, determined by potentiometric1, polarographic~ , 3 and spectrophotometric4 methods, were summarfaed. Good agreement between stability constants determined by different methods were obtained, except for the complexes specified ~n the title, which were examined spectrophotometrically and polarographically
Sonolytic degradation of ovomucin based protein matrix of hen egg white
Sonication of ovomucin based protein matrix of the thick fraction of egg white with the therapeutic ultrasound of 23 kHz frequency and 5µm amplitude causes irreversible decrease of its viscosity down to the limit value of 2.1mPa⋅s. The ultrasound treatment does not affect structure of proteins with lower molecular mass (Mm 3 x 106 g/mol) which form the thick egg white matrix. The results suggest that in analogy with avian egg white matrix, sonication-induced changes in mammalian mucin matrix of joints and tendons may constitute the therapeutical action of ultrasound.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200
The Balkan Aegean migrations revisited: changes in material culture and settlement patterns in the late bronze age central Balkans in light of new data
Alleged “Aegean migrations” have long been seen as underlying major transformations in lifeways and identity in the Balkans in the 12th–11th centuries BC. Revisiting the material culture and settlement changes in the north-south “routeway” of the Velika Morava–Južna Morava–Vardar/Axios river valleys, this paper evaluates developments within local communities. It is argued that mobility played an important role in social change, including an element of inward migration from the north. We argue that rather than an Aegean end point, these river valleys themselves were the destination of migrants. The prosperity this stimulated within those communities led to increased networks of personal mobility that incorporated elements from communities from the wider Carpathians and the north of Greece over the course of two centuries
Potentiometric Determination of the Stability Constants of 2-, 3- and 4-Hydroxybutyrato Complexes of Cobalt(II), Nickel(II), Cadmium(II) and Lead(II)
The stability constants of the title complexes were determined
potentiometrically using a quinhydrone electrode at (298.2 ± 0.1) K
in buffer solutions of ionic strength 2 mol dm-3 adjusted by addition
of NaC104• The numerical values of stability constants were evaluated
from experimental data by computer program based on a
weighted least squares method
Structural analyses of sintered MT and BZT ceramics
Development of dielectric materials is increasing with a rapid progress in mobile and satellite communications systems, where magnesium titanates find their place owing to good dielectric properties. Recently it has been established that, these materials, which are based on binary magnesium titanates (MgTi03 and Mg2Ti04) can be applied in MW engineering. These materials differ extremely low dielectric loss in the microwave range and high dielectric constant. On the other hand, barium-titanate compounds have attracted great attention for their specific microwave properties, as well. They were commonly used as parts of resonators, filters and multilayer ceramic capacitors, in the microwave region. The crystal phase with the structure BaZn2Ti40 11 is present in various commercial microwave dielectric materials based on barium-titanate compounds. Taking all this into account, in this article, the influence of mechanical activation of the MgO-Ti02 and BaCOr ZnO-Ti02 systems on phase composition, crystal structure and microstructure before and after sintering process, has been reported
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