703 research outputs found
Initiating and Improving Business Relations in Serbia: Analysis and Recommendations
The purpose of this project is to create a model for the effective initiation and improvement of business relations in The Republic of Serbia. Using Serbia as an example, different economic and cultural values will be analyzed to determine the suitability and benefits of doing business in this market. I will discuss what has been trending politically and economically in Serbia, neighboring countries, and the European Union (EU) to help fill an existing information gap. This information will be published in the interest of producing a comprehensive paper that is relevant for domestic operations, foreign investment opportunity, businesses with individual overseas assignments, or interests in expanding operations. This will include recommendations for improvement and demonstrate characteristics of the current environment for businesses that are interested in expanding their global presence to Serbia’s unique market
Tele-archaeology
Tele-archaeology, in its basic sense, may be defined as the use of telecommunications to provide archaeological information and services. Two different kinds of technology make up most of the tele-archaeology applications in use today. The first is used for transferring information from one location to another. The other is multi-way interactive knowledge distribution. In this paper we examine the possibilities of tele-archaeology, and offer a general framework to implement this technology. The main positive effect of tele-archaeology is the move towards a real “distributed interactive archaeology”, which means that archaeological knowledge building is a collective and dynamic series of tasks and processes. An individual archaeologist cannot fully explain his/her data because the explanatory process needs knowledge as raw material, and this knowledge does not exist in the individual mind of the scientist but in the research community as a global set
Electronic Structure of the Complex Hydride NaAlH4
Density functional calculations of the electronic structure of the complex
hydride NaAlH4 and the reference systems NaH and AlH3 are reported. We find a
substantially ionic electronic structure for NaAlH4, which emphasizes the
importance of solid state effects in this material. The relaxed hydrogen
positions in NaAlH4 are in good agreement with recent experiment. The
electronic structure of AlH3 is also ionic. Implications for the binding of
complex hydrides are discussed.Comment: 4 pages, 5 figure
A BLIND DECISION FEEDBACK EQUALIZER WITH EFFICIENT STRUCTURE-CRITERION SWITCHING CONTROL
This paper considers and proposes an innovated method of structure-criterion switching control for the self-optimized blind decision feedback equalizer (DFE) scheme which operates by switching between adaptation modes according to the mean square error (MSE) convergence state. The new switching control shortens the blind acquisition period time of the DFE and, consequently, speeds up its effective convergence rate. The switching control is based on the variable switching threshold which combines the commonly used MSE estimate of the DFE’s output and a posteriori error of the all-pole whitener performing front-end amplitude equalization during the blind operation mode. The efficiency of the DFE switching control is verified by simulations of single-carrier system transmitting QAM signals over multipath channels
Multi-phonon scattering and Ti-induced hydrogen dynamics in sodium alanate
We use ab initio methods and neutron inelastic scattering (NIS) to study the
structure, energetics, and dynamics of pure and Ti-doped sodium alanate
(NaAlH_4), focusing on the possibility of substitutional Ti doping. The NIS
spectrum is found to exhibit surprisingly strong and sharp two-phonon features.
The calculations reveal that substitutional Ti doping is energetically
possible. Ti prefers to substitute for Na and is a powerful hydrogen attractor
that facilitates multiple Al--H bond breaking. Our results hint at new ways of
improving the hydrogen dynamics and storage capacity of the alanates.Comment: 5 pages, with 4 postscript figures embedded. Uses REVTEX4 and
graphicx macro
Structure and Thermodynamics of the Mixed Alkali Alanates
The thermodynamics and structural properties of the hexahydride alanates
(M2M'AlH6) with the elpasolite structure have been investigated. A series of
mixed alkali alanates (Na2LiAlH6, K2LiAlH6 and K2NaAlH6) were synthesized and
found to reversibly absorb and desorb hydrogen without the need for a catalyst.
Pressure-composition isotherms were measured to investigate the thermodynamics
of the absorption and desorption reactions with hydrogen. Isotherms for
catalyzed (4 mol% TiCl3) and uncatalyzed Na2LiAlH6 exhibited an increase in
kinetics, but no change in the bulk thermodynamics with the addition of a
dopant. A structural analysis using synchrotron x-ray diffraction showed that
these compounds favor the Fm-3m space group with the smaller ion (M') occupying
an octahedral site. These results demonstrate that appropriate cation
substitutions can be used to stabilize or destabilize the material and may
provide an avenue to improving the unfavorable thermodynamics of a number of
materials with promising gravimetric hydrogen densities.Comment: 6 pages, 7 figures,3 tables, submitted to PR
Discovery of superstrong, fading, iron line emission and double-peaked Balmer lines of the galaxy SDSSJ0952+2143 - the light echo of a huge flare
We report the discovery of superstrong, fading, high-ionization iron line
emission in the galaxy SDSSJ095209.56+214313.3 (SDSSJ0952+2143 hereafter),
which must have been caused by an X-ray outburst of large amplitude.
SDSSJ0952+2143 is unique in its strong multiwavelength variability; such a
broadband emission-line and continuum response has not been observed before.
The strong iron line emission is accompanied by unusual Balmer line emission
with a broad base, narrow core and double-peaked narrow horns, and strong HeII
emission. These lines, while strong in the SDSS spectrum taken in 2005, have
faded away significantly in new spectra taken in December 2007. Comparison of
SDSS, 2MASS, GALEX and follow-up GROND photometry reveals variability in the
NUV, optical and NIR band. Taken together, these unusual observations can be
explained by a giant outburst in the EUV--X-ray band, detected even in the
optical and NIR. The intense and variable iron, Helium and Balmer lines
represent the ``light echo'' of the flare, as it traveled through circumnuclear
material. The outburst may have been caused by the tidal disruption of a star
by a supermassive black hole. Spectroscopic surveys such as SDSS are well
suited to detect emission-line light echoes of such rare flare events.
Reverberation-mapping of these light echoes can then be used as a new and
efficient probe of the physical conditions in the circumnuclear material in
non-active or active galaxies.Comment: ApJ Letters, 678, L13 (May 1 issue); incl. 4 colour figures. This and
related papers on tidal disruption flares also available at
http://www.xray.mpe.mpg.de/~skomossa
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