4,054 research outputs found
Π Π΅Π³Π΅Π½Π΅ΡΠ°ΡΠΈΠ²Π½ΡΠΉ ΡΡΠΈΠ»ΠΈΡΠ΅Π»Ρ ΡΠΈΡΠΏΠΈΡΠΎΠ²Π°Π½Π½ΡΡ ΠΈΠΌΠΏΡΠ»ΡΡΠΎΠ² Π½Π° ΠΊΡΠΈΡΡΠ°Π»Π»Π΅ Yb3+:LuAlO3 Ρ ΡΡΠΈΠ»Π΅Π½ΠΈΠ΅ΠΌ ΠΎΡΠ΄Π΅Π»ΡΠ½ΡΡ ΡΠΏΠ΅ΠΊΡΡΠ°Π»ΡΠ½ΡΡ ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½Ρ Π΄Π»Ρ ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΠΉ Π² ΡΠ΅ΡΠ°Π³Π΅ΡΡΠΎΠ²ΠΎΠΉ ΠΎΠ±Π»Π°ΡΡΠΈ ΡΠΏΠ΅ΠΊΡΡΠ°
Compact diode-pumped chirped pulse regenerative amplifier systems with pulse repetition rate of hundreds kilohertz based on Yb3+-doped crystals are of practical importance for wide range of applications such as materials processing, medicine, scientific research, etc. The aim of this work was to study the Yb3+:LuAlO3 crystal based dual wavelength chirped pulse regenerative amplifier. Perovskite-like aluminate crystals have unique spectroscopic properties that allowed to use amplifier active element gain spectrum as an amplitude filter for amplified pulse spectrum and even obtained dual wavelength amplification without any additional components. In our work a simple way to obtain dual-wavelength operation of chirped pulse regenerative amplifier by using the active medium gain spectrum as an amplitude filter for the formation of the amplified pulses spectrum demonstrated for the first time to our knowledge. Maximum output power of 5.4 W of chirped pulses (3.8 W after compression) and optical-to-optical efficiency of 22.5 % have been obtained for Yb:LuAP E//b-polarization at 200 kHz repetition rate. Compressed amplified pulse duration was about 708 fs while separate spectral components durations were 643 fs and 536 fs at 1018.3 nm and 1041.1 nm central wavelengths, respectively. Performed investigations show high potential of Yb3+:LuAP crystals as active elements of compact diode pumped chirped pulse regenerative amplifiers
ΠΡΡΠΎΠΊΠΎΠΌΠΎΡΠ½ΡΠΉ Π»Π°Π·Π΅Ρ Π½Π° ΠΊΡΠΈΡΡΠ°Π»Π»Π΅ Yb3+:YAlO3, ΡΠ°Π±ΠΎΡΠ°ΡΡΠΈΠΉ Π² ΡΠ΅ΠΆΠΈΠΌΠ΅ ΡΠΈΠ½Ρ ΡΠΎΠ½ΠΈΠ·Π°ΡΠΈΠΈ ΠΌΠΎΠ΄ Π½Π° ΠΎΡΠ½ΠΎΠ²Π΅ ΠΏΠΎΠ»ΡΠΏΡΠΎΠ²ΠΎΠ΄Π½ΠΈΠΊΠΎΠ²ΡΡ Π·Π΅ΡΠΊΠ°Π» Ρ Π½Π°ΡΡΡΠ°ΡΡΠΈΠΌΡΡ ΠΏΠΎΠ³Π»ΠΎΡΠΈΡΠ΅Π»Π΅ΠΌ
Yttrium aluminium perovskite YAlO3 (YAP) crystal, doped with rare-earth ions, has been extensively studied as a diode-pumped laser host material. The wide interest to rare-earth ions doped YAP crystals is explained by its good thermal and mechanical properties, high natural birefringence, widely used Czochralski growth method. The aim of this work was to study the Yb3+:YAlO3 crystal as an active medium for high power mode-locked laser. Yb3+-doped perovskite-like aluminate crystals have unique spectroscopic and thermooptical properties that allowed using these crystals as an active medium of high power continuous wave (CW) and modelocked (ML) bulk lasers with diode pumping. In our work spectroscopic properties of Yb:YAP crystal and laser characteristics in CW and ML regimes are investigated. Maximum output power of 4 W with optical-to-optical efficiency of 16.3 % and 140 fs pulse duration have been obtained for Yb:YAP E //c-polarization with 10 % output coupler transmittance. Tunability range as wide as 67 nm confirms high promise of using Yb:YAP crystal for lasers working in wide spectral range
Measurement of Exclusive pi(0) Electroproduction Structure Functions and their Relationship to Transverse Generalized Parton Distributions
Exclusive pi(0) electroproduction at a beam energy of 5.75 GeV has been measured with the Jefferson Lab CLAS spectrometer. Differential cross sections were measured at more than 1800 kinematic values in Q(2), x(B), t, and phi(pi), in the Q(2) range from 1.0 to 4.6 GeV2, -t up to 2 GeV2, and x(B) from 0.1 to 0.58. Structure functions sigma(T) + epsilon sigma(L), sigma(TT), and sigma(LT) were extracted as functions of t for each of 17 combinations of Q(2) and x(B). The data were compared directly with two handbag-based calculations including both longitudinal and transversity generalized parton distributions (GPDs). Inclusion of only longitudinal GPDs very strongly underestimates sigma(T) + epsilon sigma(L) and fails to account for sigma(TT) and sigma(LT), while inclusion of transversity GPDs brings the calculations into substantially better agreement with the data. There is very strong sensitivity to the relative contributions of nucleon helicity-flip and helicity nonflip processes. The results confirm that exclusive pi(0) electroproduction offers direct experimental access to the transversity GPDs
Long-term operation of a multi-channel cosmic muon system based on scintillation counters with MRS APD light readout
A Cosmic Ray Test Facility (CRTF) is the first large-scale implementation of
a scintillation triggering system based on a new scintillation technique known
as START. In START, the scintillation light is collected and transported by WLS
optical fibers, while light detection is performed by pairs of avalanche
photodiodes with the Metal-Resistor-Semiconductor structure operated in the
Geiger mode (MRS APD). START delivers 100% efficiency of cosmic muon detection,
while its intrinsic noise level is less than 10^{-2} Hz. CRTF, consisting of
160 START channels, has been continuously operated by the ALICE TOF
collaboration for more than 25 000 hours, and has demonstrated a high level of
stability. Fewer than 10% of MRS APDs had to be replaced during this period.Comment: Proceedings of NDIP-2008. 8 pages, 8 figures, 6 reference
Second virial coefficients of light nuclear clusters and their chemical freeze-out in nuclear collisions
Here we develop a new strategy to analyze the chemical freeze-out of light
(anti)nuclei produced in high energy collisions of heavy atomic nuclei within
an advanced version of the hadron resonance gas model. It is based on two
different, but complementary approaches to model the hard-core repulsion
between the light nuclei and hadrons. The first approach is based on an
approximate treatment of the equivalent hard-core radius of a roomy nuclear
cluster and pions, while the second approach is rigorously derived here using a
self-consistent treatment of classical excluded volumes of light (anti)nuclei
and hadrons. By construction, in a hadronic medium dominated by pions, both
approaches should give the same results. Employing this strategy to the
analysis of hadronic and light (anti)nuclei multiplicities measured by ALICE at
TeV and by STAR at GeV, we got rid
of the existing ambiguity in the description of light (anti)nuclei data and
determined the chemical freeze-out parameters of nuclei with high accuracy and
confidence. At ALICE energy the nuclei are frozen prior to the hadrons at the
temperature MeV, while at STAR energy there is a
single freeze-out of hadrons and nuclei at the temperature
MeV. We argue that the found chemical freeze-out volumes of nuclei can be
considered as the volumes of quark-gluon bags that produce the nuclei at the
moment of hadronization.Comment: 15 pages, 4 figures, 3 table
IoT based system for real-time monitoring the hydrogen-ion activity in water bodies
The paper presents design and principle of operation of a mobile combined pH meter. Sensorβs network underlying the IoT system for monitoring water bodies hydrogen ions activity in real time was demonstrated. The measuring device was tested on liquids with different pH levels. The obtained measurement results were compared using a stationary pH meter OHAUS Starter 3100
Electromagnetic response of the three-layer construction on the basis of barium hexaferrite and a foam glass
This paper contains results of study of the frequency dependence of reflection coefficient of the ceramic surface coated with the construction consisting of following layers: metal, composite on the basis of ferrite with hexagonal structure, and foam glass. It is shown that foam glass layer reduces significantly the reflecting characteristics of the construction
ΠΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ Ρ Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊ ΡΠΎΡΠΎΡΠ΅ΡΠΌΠΎΡΠ»Π΅ΠΊΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ Π±Π°ΡΠ°ΡΠ΅ΠΈ
Solar radiation is an environmentally friendly and affordable energy source with high release of energy. The use of a photovoltaic thermoelectric battery makes it possible to increase the efficiency of converting solar and thermal radiation into electrical energy, both on serene and cloudy days. An original battery structure with photovoltaic and thermoelectric converters is proposed. The 3D model of the proposed photovoltaic thermoelectric battery was realized in the COMSOL Multiphysics software environment with the use of a heat transfer module. The simulation was performed for the geographical coordinates of Minsk and taking into account the diurnal and seasonal variations of both the ambient temperature and the power density of the concentrated AM1.5 solar spectrum, the maximum value of which being varied from 1 to 500 kW/m2. The dependences of the maximum temperature values of the photovoltaic thermoelectric battery and the thermoelectric converters as well as temperature gradient patterns in the thermoelectric converters have been calculated. The dependences of the maximum temperature gradient values inside the thermoelectric converters on the solar power density are obtained. The graphs of the temperature gradients inside the thermoelectric converters of the photovoltaic thermoelectric battery by concentrated solar radiation versus the time of day in the middle of July and January are provided. It is shown that the output voltage increases up to the maximum values of 635 and 780 mV, respectively, in January and in July were achieved due to the temperature stabilization of the back side of the external electrodes of the proposed deviceΠ‘ΠΎΠ»Π½Π΅ΡΠ½ΠΎΠ΅ ΠΈΠ·Π»ΡΡΠ΅Π½ΠΈΠ΅ ΡΠ²Π»ΡΠ΅ΡΡΡ ΡΠΊΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈ ΡΠΈΡΡΡΠΌ ΠΈ Π΄ΠΎΡΡΡΠΏΠ½ΡΠΌ ΠΈΡΡΠΎΡΠ½ΠΈΠΊΠΎΠΌ ΡΠ½Π΅ΡΠ³ΠΈΠΈ Ρ Π²ΡΡΠΎΠΊΠΎΠΉ ΡΠ½Π΅ΡΠ³ΠΎΠΎΡΠ΄Π°ΡΠ΅ΠΉ. ΠΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ ΡΠΎΡΠΎΡΠ΅ΡΠΌΠΎΡΠ»Π΅ΠΊΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ Π±Π°ΡΠ°ΡΠ΅ΠΈ ΠΏΠΎΠ·Π²ΠΎΠ»ΡΠ΅Ρ ΡΠ²Π΅Π»ΠΈΡΠΈΡΡ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΡ ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΡ ΡΠΎΠ»Π½Π΅ΡΠ½ΠΎΠ³ΠΎ ΠΈ ΡΠ΅ΠΏΠ»ΠΎΠ²ΠΎΠ³ΠΎ ΠΈΠ·Π»ΡΡΠ΅Π½ΠΈΠΉΒ Π² ΡΠ»Π΅ΠΊΡΡΠΈΡΠ΅ΡΠΊΡΡ ΡΠ½Π΅ΡΠ³ΠΈΡ ΠΊΠ°ΠΊ Π² ΡΡΠ½ΡΠ΅, ΡΠ°ΠΊ ΠΈ Π² ΠΏΠ°ΡΠΌΡΡΠ½ΡΠ΅ Π΄Π½ΠΈ. Π Π΄Π°Π½Π½ΠΎΠΉ ΡΠ°Π±ΠΎΡΠ΅ ΠΏΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Π° ΠΎΡΠΈΠ³ΠΈΠ½Π°Π»ΡΠ½Π°Ρ ΡΡΡΡΠΊΡΡΡΠ° Π±Π°ΡΠ°ΡΠ΅ΠΈ Ρ ΡΠΎΡΠΎ- ΠΈ ΡΠ΅ΡΠΌΠΎΡΠ»Π΅ΠΊΡΡΠΈΡΠ΅ΡΠΊΠΈΠΌΠΈ ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°ΡΠ΅Π»ΡΠΌΠΈ. Π’ΡΠ΅Ρ
ΠΌΠ΅ΡΠ½Π°Ρ ΠΌΠΎΠ΄Π΅Π»Ρ ΡΠΎΡΠΎΡΠ΅ΡΠΌΠΎΡΠ»Π΅ΠΊΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ Π±Π°ΡΠ°ΡΠ΅ΠΈ ΡΠ΅Π°Π»ΠΈΠ·ΠΎΠ²Π°Π½Π° Π² ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌΠ½ΠΎΠΌ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠ΅Π½ΠΈΠΈ COMSOL Multiphysics Ρ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ ΠΌΠΎΠ΄ΡΠ»Ρ Β«Π’Π΅ΠΏΠ»ΠΎΠΏΠ΅ΡΠ΅Π΄Π°ΡΠ°Β». ΠΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΠΏΡΠΎΠ²ΠΎΠ΄ΠΈΠ»ΠΎΡΡ Π΄Π»Ρ Π³Π΅ΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΊΠΎΠΎΡΠ΄ΠΈΠ½Π°Ρ Π³. ΠΠΈΠ½ΡΠΊΠ° Ρ ΡΡΠ΅ΡΠΎΠΌ ΡΡΡΠΎΡΠ½ΠΎΠ³ΠΎ ΠΈ ΡΠ΅Π·ΠΎΠ½Π½ΠΎΠ³ΠΎ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΠΉ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ ΠΎΠΊΡΡΠΆΠ°ΡΡΠ΅ΠΉ ΡΡΠ΅Π΄Ρ ΠΈ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΠΈ ΠΌΠΎΡΠ½ΠΎΡΡΠΈ ΠΊΠΎΠ½ΡΠ΅Π½ΡΡΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠ³ΠΎ ΡΠΎΠ»Π½Π΅ΡΠ½ΠΎΠ³ΠΎ ΠΈΠ·Π»ΡΡΠ΅Π½ΠΈΡ ΡΠΏΠ΅ΠΊΡΡΠ° AM1.5, ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠ΅ Π·Π½Π°ΡΠ΅Π½ΠΈΠ΅ ΠΊΠΎΡΠΎΡΠΎΠΉ Π²Π°ΡΡΠΈΡΠΎΠ²Π°Π»ΠΎΡΡ ΠΎΡ 1 Π΄ΠΎ 500 ΠΊΠΡ/ΠΌ2. Π Π°ΡΡΡΠΈΡΠ°Π½Ρ Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΡΡ
Π·Π½Π°ΡΠ΅Π½ΠΈΠΉ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ ΡΠΎΡΠΎΡΠ΅ΡΠΌΠΎΡΠ»Π΅ΠΊΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ Π±Π°ΡΠ°ΡΠ΅ΠΈ, ΡΠ΅ΡΠΌΠΎΡΠ»Π΅ΠΊΡΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°ΡΠ΅Π»Π΅ΠΉ, Π° ΡΠ°ΠΊΠΆΠ΅ ΠΏΡΠΎΡΠΈΠ»ΠΈ ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ Π³ΡΠ°Π΄ΠΈΠ΅Π½ΡΠ° ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ Π² ΡΠ΅ΡΠΌΠΎΡΠ»Π΅ΠΊΡΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°ΡΠ΅Π»ΡΡ
. ΠΠΎΠ»ΡΡΠ΅Π½Ρ Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΡΡ
Π·Π½Π°ΡΠ΅Π½ΠΈΠΉ Π³ΡΠ°Π΄ΠΈΠ΅Π½ΡΠ° ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ Π²Π½ΡΡΡΠΈ ΡΠ΅ΡΠΌΠΎΡΠ»Π΅ΠΊΡΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°ΡΠ΅Π»Π΅ΠΉ ΠΎΡ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΠΈ ΠΌΠΎΡΠ½ΠΎΡΡΠΈ ΡΠΎΠ»Π½Π΅ΡΠ½ΠΎΠ³ΠΎ ΠΈΠ·Π»ΡΡΠ΅Π½ΠΈΡ. ΠΠΎΡΡΡΠΎΠ΅Π½Ρ Π³ΡΠ°ΡΠΈΠΊΠΈ Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠ΅ΠΉ Π³ΡΠ°Π΄ΠΈΠ΅Π½ΡΠΎΠ² ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ Π²Π½ΡΡΡΠΈ ΡΠ΅ΡΠΌΠΎΡΠ»Π΅ΠΊΡΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°ΡΠ΅Π»Ρ ΡΠΎΡΠΎΡΠ΅ΡΠΌΠΎΡΠ»Π΅ΠΊΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ Π±Π°ΡΠ°ΡΠ΅ΠΈ ΠΏΡΠΈ Π²ΠΎΠ·Π΄Π΅ΠΉΡΡΠ²ΠΈΠΈ ΠΊΠΎΠ½ΡΠ΅Π½ΡΡΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠ³ΠΎ ΡΠΎΠ»Π½Π΅ΡΠ½ΠΎΠ³ΠΎ ΠΈΠ·Π»ΡΡΠ΅Π½ΠΈΡ ΠΎΡ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ ΡΡΡΠΎΠΊ Π² ΡΠ΅ΡΠ΅Π΄ΠΈΠ½Π΅ ΠΈΡΠ»Ρ ΠΈ ΡΠ½Π²Π°ΡΡ. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ Π·Π° ΡΡΠ΅Ρ ΡΠ΅ΡΠΌΠΎΡΡΠ°Π±ΠΈΠ»ΠΈΠ·Π°ΡΠΈΠΈ ΡΡΠ»ΡΠ½ΠΎΠΉ ΡΡΠΎΡΠΎΠ½Ρ Π²Π½Π΅ΡΠ½ΠΈΡ
ΡΠ»Π΅ΠΊΡΡΠΎΠ΄ΠΎΠ² ΠΏΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Π½ΠΎΠ³ΠΎ ΡΡΡΡΠΎΠΉΡΡΠ²Π° ΡΠ΄Π°Π»ΠΎΡΡ Π΄ΠΎΡΡΠΈΡΡ ΡΠ²Π΅Π»ΠΈΡΠ΅Π½ΠΈΡ Π²ΡΡ
ΠΎΠ΄Π½ΠΎΠ³ΠΎ Π½Π°ΠΏΡΡΠΆΠ΅Π½ΠΈΡ Π΄ΠΎ ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΡΡ
Π·Π½Π°ΡΠ΅Π½ΠΈΠΉ 635Β ΠΌΠ Π² ΡΠ½Π²Π°ΡΠ΅ ΠΈ 780 ΠΌΠ Π² ΠΈΡΠ»Π΅.
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