335 research outputs found
Using parallel computing in modeling and optimization of mineral reserves extraction systems
Annotation This article describes algorithm for solving ultimate pit limit problem (UPIT), or a maximum weight closure problem. There are several method for solving this problem. We provide new approach, for solving ultimate pit limit problem using precedence model. Block model of open pit can be easily represented as an oriented graph. Then to solve ultimate pit limit problem it is required to find such a sub graph in a graph whose sum of weights will be maximal. One of the possible solutions of this problem is using genetic algorithms. We use a parallel genetic algorithm for accelerating of computational process. In this version of algorithm fitness function of each individual calculating in different thread. It allows reducing running time of algorithm. Details of implementation parallel genetic algorithm for searching open pit limits are provided. Comparison with other methods and results of computational experiments provided.Keywords: open pit limits, genetics algorithms, high-performance computin
Effect of Nitrogen Implantation on the Structure and Properties of Austenitic Corrosion-Resistant Steels
Work is devoted to studying the effect of implantation of nitrogen ions into the surface of austenitic stainless steels to improve their functional properties. Four grades of austenitic corrosion-resistant steels 02H16N10M2, 08H15AG10D2, 06H15AG9NM2 and 09H15AG9ND2 were taken after cold plastic deformation and annealing from 680 ∘C in water and subsequent implantation with N+ ions with different radiation dose: 0,01 и 0,1%. It was found that irradiation of austenitic stainless steels with nitrogen ions can be considered an effective way to increase the hardness and yield strength of steels in the operation in a corrosive environment.
Keywords: steel, austenite, nitrogen implantation, hardness, corrosion resistanc
Two−photon Processes in Organometallic Molecules and Clusters: T−T Absorption of Group IV Metal Complexes
Triplet – triplet absorption of d0 metal complexes was for the first time revealed and studied by means of pulse photolysis and electron-exchange (Dexter) resonant energy transfer energy transfer.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3539
First study of radiation hardness of lead tungstate crystals at low temperatures
The electromagnetic calorimeter of PANDA at the FAIR facility will rely on an
operation of lead tungstate (PWO) scintillation crystals at temperatures near
-25 deg.C to provide sufficient resolution for photons in the energy range from
8 GeV down to 10 MeV. Radiation hardness of PWO crystals was studied at the
IHEP (Protvino) irradiation facility in the temperature range from room
temperature down to -25 deg.C. These studies have indicated a significantly
different behaviour in the time evolution of the damaging processes well below
room temperature. Different signal loss levels at the same dose rate, but at
different temperatures were observed. The effect of a deep suppression of the
crystal recovery process at temperatures below
0 deg.C has been seen.Comment: 10 pages 7 figure
Subcarrier Wave Quantum Key Distribution in Telecommunication Network with Bitrate 800 kbit/s
In the course of work on creating the first quantum communication network in Russia we demonstrated quantum key distribution in metropolitan optical network infrastructure. A single-pass subcarrier wave quantum cryptography scheme was used in the experiments. BB84 protocol with strong reference was chosen for performing key distribution. The registered sifted key rate in an optical cable with 1.5 dB loss was 800 Kbit/s. Signal visibility exceeded 98%, and quantum bit error rate value was 1%. The achieved result is a record for this type of systems
Development of a Momentum Determined Electron Beam in the 1 -45 GeV Range
A beam line for electrons with energies in the range of 1 to 45 GeV, low
contamination of hadrons and muons and high intensity up to 10^6 per
accelerator spill at 27 GeV was setup at U70 accelerator in Protvino, Russia. A
beam tagging system based on drift chambers with 160 micron resolution was able
to measure relative electron beam momentum precisely. The resolution sigma_p p
was 0.13% at 45 GeV where multiple scattering is negligible. This test beam
setup provided the possibility to study properties of lead tungstate crystals
(PbWO_4) for the BTeV experiment at Fermilab.Comment: 12 pages, 8 figures; work done by the BTeV Electromagnetic
Calorimeter grou
Performance of a fine-sampling electromagnetic calorimeter prototype in the energy range from 1 to 19 GeV
The fine-sampling electromagnetic calorimeter prototype has been
experimentally tested using the 1-19 GeV/c tagged beams of negatively charged
particles at the U70 accelerator at IHEP, Protvino. The energy resolution
measured by electrons is Delta{E}/E=2.8%/\sqrt{E} + 1.3%. The position
resolution for electrons is Delta{x}=3.1 + 15.4/sqrt{E} mm in the center of the
cell. The lateral non-uniformity of the prototype energy response to electrons
and MIPs has turned out to be negligible. Obtained experimental results are in
a good agreement with Monte-Carlo simulations.Comment: Article is prepared for pdflatex using the class elsart. 13 pages, 9
figures in 11 PDF file
Comparison of Radiation Damage in Lead Tungstate Crystals under Pion and Gamma Irradiation
Studies of the radiation hardness of lead tungstate crystals produced by the
Bogoroditsk Techno-Chemical Plant in Russia and the Shanghai Institute of
Ceramics in China have been carried out at IHEP, Protvino. The crystals were
irradiated by a 40-GeV pion beam. After full recovery, the same crystals were
irradiated using a -ray source. The dose rate profiles along
the crystal length were observed to be quite similar. We compare the effects of
the two types of radiation on the crystals light output.Comment: 10 pages, 8 figures, Latex 2e, 28.04.04 - minor grammatical change
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