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Institute of Applied Physics

facilityMinsk, Belarus

Research output, citation impact, and the most-cited recent papers from Institute of Applied Physics (Belarus). Aggregated across the NobleBlocks index of 300M+ scholarly works.

Total works
1.6K
Citations
15.0K
h-index
45
i10-index
379
Also known as
Institute of Applied PhysicsInstitute of Applied Physics of the National Academy of Sciences of BelarusИнститут прикладной физики Национальной академии наук Беларуси

Top-cited papers from Institute of Applied Physics

Extraction and validation of a new set of CMS pythia8 tunes from underlying-event measurements
A. M. Sirunyan, A. Tumasyan, W. Adam, F. Ambrogi +4 more
2020· The European Physical Journal C413doi:10.1140/epjc/s10052-019-7499-4

New sets of CMS underlying-event parameters ("tunes") are presented for the pythia8 event generator. These tunes use the NNPDF3.1 parton distribution functions (PDFs) at leading (LO), next-to-leading (NLO), or next-to-next-to-leading (NNLO) orders in perturbative quantum chromodynamics, and the strong coupling evolution at LO or NLO. Measurements of charged-particle multiplicity and transverse momentum densities at various hadron collision energies are fit simultaneously to determine the parameters of the tunes. Comparisons of the predictions of the new tunes are provided for observables sensitive to the event shapes at LEP, global underlying event, soft multiparton interactions, and double-parton scattering contributions. In addition, comparisons are made for observables measured in various specific processes, such as multijet, Drell-Yan, and top quark-antiquark pair production including jet substructure observables. The simulation of the underlying event provided by the new tunes is interfaced to a higher-order matrix-element calculation. For the first time, predictions from pythia8 obtained with tunes based on NLO or NNLO PDFs are shown to reliably describe minimum-bias and underlying-event data with a similar level of agreement to predictions from tunes using LO PDF sets.

EARLINET correlative measurements for CALIPSO: First intercomparison results
Gelsomina Pappalardo, Ulla Wandinger, Lucia Mona, Anja Hiebsch +4 more
2010· Journal of Geophysical Research Atmospheres291doi:10.1029/2009jd012147

A strategy for European Aerosol Research Lidar Network (EARLINET) correlative measurements for Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) has been developed. These EARLINET correlative measurements started in June 2006 and are still in progress. Up to now, more than 4500 correlative files are available in the EARLINET database. Independent extinction and backscatter measurements carried out at high‐performance EARLINET stations have been used for a quantitative comparison with CALIPSO level 1 data. Results demonstrate the good performance of CALIPSO and the absence of evident biases in the CALIPSO raw signals. The agreement is also good for the distribution of the differences for the attenuated backscatter at 532 nm ((CALIPSO‐EARLINET)/EARLINET (%)), calculated in the 1–10 km altitude range, with a mean relative difference of 4.6%, a standard deviation of 50%, and a median value of 0.6%. A major Saharan dust outbreak lasting from 26 to 31 May 2008 has been used as a case study for showing first results in terms of comparison with CALIPSO level 2 data. A statistical analysis of dust properties, in terms of intensive optical properties (lidar ratios, Ångström exponents, and color ratios), has been performed for this observational period. We obtained typical lidar ratios of the dust event of 49 ± 10 sr and 56 ± 7 sr at 355 and 532 nm, respectively. The extinction‐related and backscatter‐related Ångström exponents were on the order of 0.15–0.17, which corresponds to respective color ratios of 0.91–0.95. This dust event has been used to show the methodology used for the investigation of spatial and temporal representativeness of measurements with polar‐orbiting satellites.

Semianalytical cloud retrieval algorithm as applied to the cloud top altitude and the cloud geometrical thickness determination from top‐of‐atmosphere reflectance measurements in the oxygen A band
В. В. Розанов, Alexander Kokhanovsky
2004· Journal of Geophysical Research Atmospheres135doi:10.1029/2003jd004104

The paper is devoted to the development of the asymptotic algorithm for the cloud top height h and the geometrical thickness l determination using measurements of the cloud reflection function. It is based on the asymptotic theory of the radiative transfer in the oxygen absorption bands and simple parameterization of the radiative transport in the atmosphere above and under a cloud. In particular, we have studied the influence of the error of the developed approximate theory on the accuracy of the retrieval of the pair ( h , l ). It was assumed that there is only a single cloud layer having the same value of the liquid water content in all points inside the cloud. The values ( h , l ) have been found, solving the inverse problem having as input the synthetic spectra of backscattered light. The synthetic spectra were found using the exact solution of the forward problem for given values of ( h , l ). The retrieval technique was based on the asymptotic theory. We have found that the error of the cloud top height determination is smaller than 20 m, and the error of the cloud geometrical thickness determination is smaller than 500 m for solar angles 20–70 degrees, values of h in the range 1–12 km, values of geometrical thickness l in the range 0.5–2 km, and values of the cloud optical thickness changing in the range 10–50. The surface albedo has been assumed to be equal zero. We have also studied the influence of the cloud liquid water profile on the results of the retrieval of the pair ( h , l ). It was found that the error of the cloud top height determination increases up to 600 m, if the assumed cloud has a changing with height liquid water content, and retrievals are made applying the inversion with assumed constant liquid water content profile. The error in the geometrical thickness increases up to 1 km in this case. Errors of the retrieval increase even further if the retrieval, on the basis of the homogeneous layer theory, is applied to the two‐layered cloud system (e.g., the upper cloud consists of ice crystals and the lower cloud is in a liquid phase). This signifies the importance of the cloud vertical inhomogeneity on the retrieval results.

Cirrus cloud microphysical and optical properties at southern and northern midlatitudes during the INCA experiment
Jean‐François Gayet, J. Ovarlez, Valéry Shcherbakov, J. Ström +4 more
2004· Journal of Geophysical Research Atmospheres134doi:10.1029/2004jd004803

Microphysical and optical measurements were performed in midlatitude cirrus clouds at temperatures between −33°C and −60°C during southern and northern Interhemispheric Differences in Cirrus Properties From Anthropogenic Emissions (INCA) field experiments carried out at equivalent latitudes (53°S and 55°N) from Punta Arenas in the Southern Hemisphere (SH, Chile) and Prestwick in the Northern Hemisphere (NH, Scotland). The aim of this paper is to analyze the microphysical and optical properties of cirrus clouds and to compare the results of the two campaigns. Compared with the mean properties of cirrus clouds in SH, the cirrus sampled in NH were characterized by a greater concentration of ice crystals (2.2 cm −3 versus 1.4 cm −3 , respectively) with a lower effective diameter (36 μm versus 42 μm, respectively). A significant contrast in extinction coefficient was also evidenced with larger values in NH than in SH (0.61 km −1 versus 0.49 km 1 , respectively), whereas no significant differences in the ice water content were observed (8 mg m −3 ). The first measurements of the asymmetry parameter obtained in midlatitude cirrus clouds revealed rather uniform particle scattering properties (median g values between 0.76 and 0.78) with small differences between SH and NH (0.770 versus 0.767, respectively). No significant differences in crystal shape were evidenced between the two data sets. For similar environmental conditions (i.e., over a similar range of temperature and vertical velocity) and for given values of the relative humidity, the comparisons clearly show distinct differences between the microphysical and optical properties of cirrus clouds sampled in the SH and NH field experiments. These differences may be related to the contrasts in cirrus freezing thresholds in terms of relative humidity over ice for onset of clouds, which is about 20% lower in NH than in SH, as reported in previous INCA data analyses. Nevertheless, definite conclusions are hampered by the large natural variability of cirrus cloud properties and the limited number of flights performed, not forgetting both the actual freezing mechanisms and potential differences in small‐scale dynamical variability, which are still insufficiently understood.

Measurement of prompt and nonprompt charmonium suppression in $$\text {PbPb}$$ collisions at 5.02$$\,\text {Te}\text {V}$$
A. M. Sirunyan, A. Tumasyan, W. Adam, F. Ambrogi +4 more
2018· The European Physical Journal C129doi:10.1140/epjc/s10052-018-5950-6

Abstract The nuclear modification factors of $${\mathrm {J}/\psi }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>J</mml:mi> <mml:mo>/</mml:mo> <mml:mi>ψ</mml:mi> </mml:mrow> </mml:math> and $$\psi \text {(2S)}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>ψ</mml:mi> <mml:mtext>(2S)</mml:mtext> </mml:mrow> </mml:math> mesons are measured in $$\text {PbPb}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mtext>PbPb</mml:mtext> </mml:math> collisions at a centre-of-mass energy per nucleon pair of $$\sqrt{\smash [b]{s_{_{\text {NN}}}}} = 5.02\,\text {Te}\text {V} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msqrt> <mml:mpadded> <mml:msub> <mml:mi>s</mml:mi> <mml:msub> <mml:mrow/> <mml:mtext>NN</mml:mtext> </mml:msub> </mml:msub> </mml:mpadded> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>5.02</mml:mn> <mml:mspace/> <mml:mtext>TeV</mml:mtext> </mml:mrow> </mml:math> . The analysis is based on $$\text {PbPb}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mtext>PbPb</mml:mtext> </mml:math> and $$\mathrm {p}\mathrm {p}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>p</mml:mi> <mml:mi>p</mml:mi> </mml:mrow> </mml:math> data samples collected by CMS at the LHC in 2015, corresponding to integrated luminosities of 464 $$\,\mu \mathrm {b}^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mspace/> <mml:mi>μ</mml:mi> <mml:msup> <mml:mrow> <mml:mi>b</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> and 28 $$\,\text {pb}^\text {-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mspace/> <mml:msup> <mml:mtext>pb</mml:mtext> <mml:mtext>-1</mml:mtext> </mml:msup> </mml:mrow> </mml:math> , respectively. The measurements are performed in the dimuon rapidity range of $$|y | &lt; 2.4$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>|</mml:mo> <mml:mi>y</mml:mi> <mml:mo>|</mml:mo> <mml:mo>&lt;</mml:mo> <mml:mn>2.4</mml:mn> </mml:mrow> </mml:math> as a function of centrality, rapidity, and transverse momentum ( $$p_{\mathrm {T}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>p</mml:mi> <mml:mi>T</mml:mi> </mml:msub> </mml:math> ) from $$p_{\mathrm {T}} =3$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>p</mml:mi> <mml:mi>T</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>3</mml:mn> </mml:mrow> </mml:math> $${\,\text {Ge}\text {V}/}\text {c}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mrow> <mml:mspace/> <mml:mtext>GeV</mml:mtext> <mml:mo>/</mml:mo> </mml:mrow> <mml:mtext>c</mml:mtext> </mml:mrow> </mml:math> in the most forward region and up to 50 $${\,\text {Ge}\text {V}/}\text {c}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mrow> <mml:mspace/> <mml:mtext>GeV</mml:mtext> <mml:mo>/</mml:mo> </mml:mrow> <mml:mtext>c</mml:mtext> </mml:mrow> </mml:math> . Both prompt and nonprompt (coming from b hadron decays) $${\mathrm {J}/\psi }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>J</mml:mi> <mml:mo>/</mml:mo> <mml:mi>ψ</mml:mi> </mml:mrow> </mml:math> mesons are observed to be increasingly suppressed with centrality, with a magnitude similar to the one observed at $$\sqrt{\smash [b]{s_{_{\text {NN}}}}} = 2.76\,\text {Te}\text {V} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msqrt> <mml:mpadded> <mml:msub> <mml:mi>s</mml:mi> <mml:msub> <mml:mrow/> <mml:mtext>NN</mml:mtext> </mml:msub> </mml:msub> </mml:mpadded> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>2.76</mml:mn> <mml:mspace/> <mml:mtext>TeV</mml:mtext> </mml:mrow> </mml:math> for the two $${\mathrm {J}/\psi }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>J</mml:mi> <mml:mo>/</mml:mo> <mml:mi>ψ</mml:mi> </mml:mrow> </mml:math> meson components. No dependence on rapidity is observed for either prompt or nonprompt $${\mathrm {J}/\psi }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>J</mml:mi> <mml:mo>/</mml:mo> <mml:mi>ψ</mml:mi> </mml:mrow> </mml:math> mesons. An indication of a lower prompt $${\mathrm {J}/\psi }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>J</mml:mi> <mml:mo>/</mml:mo> <mml:mi>ψ</mml:mi> </mml:mrow> </mml:math> meson suppression at $$p_{\mathrm {T}} &gt; 25$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>p</mml:mi> <mml:mi>T</mml:mi> </mml:msub> <mml:mo>&gt;</mml:mo> <mml:mn>25</mml:mn> </mml:mrow> </mml:math> $${\

On-line temperature monitoring in selective laser sintering/melting
Yu. Chivel, I. Smurov
2010· Physics Procedia122doi:10.1016/j.phpro.2010.08.079

Poor efficiency of selective laser sintering/ melting (SLS/SLM) processes and poor articles surface quality are mainly responsible for their slow manufacturing application. That is why optical monitoring has paramount importance for SLS/SLM process resulting part quality. The optical systems for temperature monitoring of SLS/SLM process are developed and integrated with industrial SLS/SLM machines. The system provides the possibility to spatial distribution of brightness temperature at two wavelengths and selected temperature profiles, calculation of colour temperature and express analysis of possible deviations of the maximum temperature from its optimal value. Optimal regimes of SLS process for the sintering of the high porosity powder body was determined.

Measurement of the weak mixing angle using the forward–backward asymmetry of Drell–Yan events in $$\mathrm {p}\mathrm {p}$$ p p collisions at 8 $$\,\text {TeV}$$ TeV
A. M. Sirunyan, A. Tumasyan, W. Adam, F. Ambrogi +4 more
2018· The European Physical Journal C87doi:10.1140/epjc/s10052-018-6148-7

A measurement is presented of the effective leptonic weak mixing angle (sin 2 eff ) using the forwardbackward asymmetry of Drell-Yan lepton pairs ( and ee) produced in proton-proton collisions at s = 8 TeV at the CMS experiment of the LHC. The data correspond to integrated luminosities of 18.8 and 19.6 fb -1 in the dimuon and dielectron channels, respectively, containing 8.2 million dimuon and 4.9 million dielectron events. With more events and new analysis techniques, including constraints obtained on the parton distribution functions from the measured forward-backward asymmetry, the statistical and systematic uncertainties are significantly reduced relative to previous CMS measurements. The extracted value of sin 2 eff from the combined dilepton data is sin 2 eff = 0.23101 0.00036 (stat) 0.00018 (syst) 0.00016 (theo) 0.00031 (parton distributions in proton) = 0.23101 0.00053.

Low viscosity, high birefringence liquid crystalline compounds and mixtures
R. Dąbrowski, Jerzy Dziaduszek, A. Ziółek, Ł. Szczuciński +4 more
2006· Opto-Electronics Review81doi:10.2478/s11772-006-0055-4

Abstract Two types of fast switching mixtures with high positive dielectric anisotropy were described. The first type, with a birefringence below 0.3, was designed for devices operating at room or lower temperatures and the second one, with a birefringence higher than 0.3 for devices operating at elevated temperatures.

Formation of discontinuous tracks in single-crystalline InP by 250-MeV Xe-ion irradiation
O. Herre, W. Wesch, E. Wendler, П. И. Гайдук +3 more
1998· Physical review. B, Condensed matter79doi:10.1103/physrevb.58.4832

Damage production was studied in 250-MeV Xe-ion irradiated single-crystalline InP by means of Rutherford backscattering spectrometry using a channeling technique and cross-section TEM. Different concentrations and types of defects are created at different depths of the trajectory due to the different dominating interaction processes. Depending on the ion fluence the formation of discontinuous tracks and amorphous layers was registered in the depth region of high electronic energy loss of the incident ions. The observed findings are interpreted as the effect of a thermal spike in combination with damage accumulation resulting from imperfect epitaxial recrystallization of the molten ion tracks.

Axicon-based Bessel resonator: analytical description and experiment
Anatol Khilo, Eugeny G. Katranji, А. А. Рыжевич
2001· Journal of the Optical Society of America A76doi:10.1364/josaa.18.001986

We present a new scheme for an optical resonator for production of Bessel and Bessel-Gauss light beams. The resonator with Bessel modes is composed of two plane mirrors with an axicon placed close to one of them. If this mirror is concave, the modes are Bessel-Gauss light beams. Analytical expressions relating parameters of the resonator and characteristics of its modes are obtained and analyzed. The results are verified with the Fox-Li algorithm. The resonator scheme was implemented in an experiment to confirm the possibility of the generation of zero-order Bessel beams. It was found that multipass modes can also oscillate in the resonator if its apertures are large enough.

Chromium-doped forsterite as a solid-state saturable absorber
M. I. Demchuk, V. P. Mikhailov, N. Zhavoronkov, Н. В. Кулешов +4 more
1992· Optics Letters69doi:10.1364/ol.17.000929

Saturation of near-infrared absorption in Mg(2)SiO(4):Cr is observed, and the absorption cross section at 1.08 microm is estimated to be sigma(alpha) = (2.3 +/- 0.3) x 10(-18) cm(2). Q switching and passive mode locking of a Nd:YAG laser have been realized with a Mg(2)SiO(4):Cr saturable absorber.

Improved technique for data inversion: optical sizing of multicomponent aerosols
Оleg Dubovik, Tatyana Lapyonok, Sergey Oshchepkov
1995· Applied Optics59doi:10.1364/ao.34.008422

Estimation of particle-size distribution is analyzed for the complicated case of compound aerosols, in which particles are distinguished by sizes and optical constants. This task arises in a number of interesting practical situations when aerosol scatterers cannot be described with a common refractive index. This is an inverse problem with a large number of variables, and questions of formal inversion are of great importance here. They are discussed in detail, and an improved numerical-inversion method is proposed. The method provides a nonnegative and highly stable solution and makes it possible to include varied additional or a priori information. It is shown that the proposed technique is closely related to well-known linear and relaxation methods widely used in atmospheric optics. The algorithm for determination of bicomponent aerosol-size distribution is devised. It uses the intensity of light scattered at different angles and spectral-extinction measurements. In addition, the algorithm can incorporate a priori restrictions of size-spectra smoothness. A set of numerical examples illustrates the algorithm.

Two-step inverse scattering method for one-dimensional permittivity profiles
V. Mikhnev, P. Vainikainen
2000· IEEE Transactions on Antennas and Propagation55doi:10.1109/8.833079

A numerical method to invert the dielectric permittivity profile from the Riccati equation using the Newton-Kantorovich iterative scheme is described. Instead of handling the equations in terms of usual geometrical depth, we determine the profile as a function of the electromagnetic path length since the convergence and the stability of the solution are found to be significantly better in this case. The initial profile used as a starting point for the inversion is obtained by another method employing successive reconstruction of dielectric interfaces and homogeneous layers in a step-like form. This method, though not always accurate, is fast and well suited for the approximate reconstruction of the profile, thus creating ideal starting conditions for the previous approach. As a result, the computation time is considerably reduced, without using any a priori information. The approach is applicable to both continuous and discontinuous profiles of high contrast and exhibits a good stability of the solution with respect to noisy input data. A lossy medium profile can also be inverted provided the overall thickness of the inhomogeneous slab and the background permittivity are known.

Efficient continuous-wave frequency doubling of a tunable CO_2 laser in AgGaSe_2
Sergei Tochitsky, V. O. Petukhov, V. A. Gorobets, V. V. Churakov +1 more
1997· Applied Optics52doi:10.1364/ao.36.001882

Second-harmonic output at 4.6-5.5 mum of the order of 6 mW with a 0.12% external conversion efficiency has been obtained by pumping a AgGaSe(2) crystal with a low-power cw CO(2) laser. The surface damage threshold of AgGaSe(2) for cw radiation was found to be inside the limit of 33-45 kW/cm(2) in the 9.2-10.8-mum wavelength region. Another important limitation of the pump power connected with a thermal lensing effect in crystal was determined experimentally. A comparison was made of AgGaSe(2) and ZnGeP(2) crystals as materials suitable for the efficient generation of the second harmonic of cw CO(2) laser radiation.

Ion mass and temperature dependence of damage production in ion implanted InP
E. Wendler, T. Opfermann, П. И. Гайдук
1997· Journal of Applied Physics50doi:10.1063/1.366499

Ion beam induced damaging and amorphization of crystalline InP is investigated. 100 keV B+, 300 keV Si+, 200 keV Ar+ and 600 keV Se+ ions are implanted into 〈100〉 InP at temperatures ranging from 80 K to 420 K. The implanted layers are analyzed using Rutherford backscattering spectrometry in channeling configuration, cross section transmission electron microscopy and optical spectroscopy in the sub-gap frequency region. The temperature dependence of damage production can be represented assuming a thermally stimulated defect diffusion within the primary collision cascades, resulting in a shrinkage of the remaining defect clusters. At a critical temperature T∞ these clusters dissolve completely and only point defect complexes nucleate. Then, amorphization occurs only at very large ion fluences (≈1016cm−2) and the process seems to be influenced by the high amount of implanted ions. A defect band forms around the projected range of the implanted ions, which may act as a diffusion barrier for point defects. The range of T∞ from ≈350 K for B+ and ≈420 K for Se+ ions corresponds to the annealing stage II of defects in InP, which can be related to the mobility of phosphorous interstitials. This indicates that phosphorous interstitials play an important role during ion irradiation of InP.

Integral light-scattering and absorption characteristics of large, nonspherical particles
Alexander Kokhanovsky, Andreas Macke
1997· Applied Optics45doi:10.1364/ao.36.008785

We obtain and analyze simple analytical formulas for asymmetry parameters and absorption cross sections of large, nonspherical particles. The formulas are based on the asymptotic properties of these characteristics at strong and weak absorption of radiation inside particles. The absorption cross section depends on parameter phi, which determines the value of the light-absorption cross section for weakly absorbing particles. It is larger for nonspherical scatterers. The asymmetry parameter depends on two parameters. The first is the asymmetry parameter g(0) of a nonspherical, transparent particle with the same shape as an absorbing one. The second parameter, beta, determines the strength of the influence of light absorption on the value of the asymmetry parameter. Parameter beta is larger for nonspherical particles. One can find these three parameters (phi, g(0), and beta) using a ray-tracing code (RTC) for nonabsorbing and weakly absorbing particles. The RTC can then be used to check the accuracy of the equations at any absorption for hexagonal cylinders and spheroids. It is found that the error of computing the absorption cross section and 1 - g (g is the asymmetry parameter) is less than 20% at the refractive index of particles n = 1.333. Values for asymmetry parameters of large, nonabsorbing, spheroidal particles with different aspect ratios are tabulated for the first time to our knowledge. They do not depend on the size of particles and can serve as an independent check of the accuracy of T-matrix codes for large parameters.

New highly anisotropic liquid crystal materials for high-frequency applications
В. И. Лапаник, Genadz Sasnouski, Sergei Timofeev, Elena Shepeleva +2 more
2018· Liquid Crystals45doi:10.1080/02678292.2018.1427810

We report on the developed liquid crystal (LC) compositions with large optical anisotropy and low melting point on the basis of synthesised quaterphenyl and quinquiphenyl LC compounds containing lateral substituents. Optical and dielectric anisotropies of synthesised compounds were studied to select the most optimal compounds for high-frequency applications. As a result of the research, base matrices with a wide range of the nematic phase were developed and their mesomorphic and physicochemical properties were investigated. Based on the experimental data, the influence of various fragments of molecules on the magnitude of permittivity in the high-frequency region, as well as on the loss tangent of LCs was established.

A multi-dimensional search for new heavy resonances decaying to boosted $$\text{ W }{}{}$$ $$\text{ W }{}{}$$ , $$\text{ W }{}{}$$ $$\text{ Z }{}{}$$ , or $$\text{ Z }{}{}$$ $$\text{ Z }{}{}$$ boson pairs in the dijet final state at 13 $$\text {Te}\text {V}$$
A. M. Sirunyan, A. Tumasyan, W. Adam, F. Ambrogi +4 more
2020· The European Physical Journal C43doi:10.1140/epjc/s10052-020-7773-5

Abstract A search in an all-jet final state for new massive resonances decaying to $$\text{ W }{}{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mspace/><mml:mtext>W</mml:mtext><mml:mspace/><mml:mrow/><mml:mrow/></mml:mrow></mml:math> $$\text{ W }{}{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mspace/><mml:mtext>W</mml:mtext><mml:mspace/><mml:mrow/><mml:mrow/></mml:mrow></mml:math> , $$\text{ W }{}{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mspace/><mml:mtext>W</mml:mtext><mml:mspace/><mml:mrow/><mml:mrow/></mml:mrow></mml:math> $$\text{ Z }{}{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mspace/><mml:mtext>Z</mml:mtext><mml:mspace/><mml:mrow/><mml:mrow/></mml:mrow></mml:math> , or $$\text{ Z }{}{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mspace/><mml:mtext>Z</mml:mtext><mml:mspace/><mml:mrow/><mml:mrow/></mml:mrow></mml:math> $$\text{ Z }{}{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mspace/><mml:mtext>Z</mml:mtext><mml:mspace/><mml:mrow/><mml:mrow/></mml:mrow></mml:math> boson pairs using a novel analysis method is presented. The analysis is performed on data corresponding to an integrated luminosity of 77.3 $$\,\text {fb}^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mspace/><mml:msup><mml:mtext>fb</mml:mtext><mml:mrow><mml:mo>-</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math> recorded with the CMS experiment at the LHC at a centre-of-mass energy of 13 $$\text {Te}\text {V}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mtext>Te</mml:mtext><mml:mspace/></mml:mrow></mml:math> . The search is focussed on potential narrow-width resonances with masses above 1.2 $$\text {Te}\text {V}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mtext>Te</mml:mtext><mml:mspace/></mml:mrow></mml:math> , where the decay products of each $$\text{ W }{}{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mspace/><mml:mtext>W</mml:mtext><mml:mspace/><mml:mrow/><mml:mrow/></mml:mrow></mml:math> or $$\text{ Z }{}{}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mspace/><mml:mtext>Z</mml:mtext><mml:mspace/><mml:mrow/><mml:mrow/></mml:mrow></mml:math> boson are expected to be collimated into a single, large-radius jet. The signal is extracted using a three-dimensional maximum likelihood fit of the two jet masses and the dijet invariant mass, yielding an improvement in sensitivity of up to 30% relative to previous search methods. No excess is observed above the estimated standard model background. In a heavy vector triplet model, spin-1 $${\text {Z}}^{\prime }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow><mml:mtext>Z</mml:mtext></mml:mrow><mml:mo>′</mml:mo></mml:msup></mml:math> and $${\text {W}}^{\prime }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow><mml:mtext>W</mml:mtext></mml:mrow><mml:mo>′</mml:mo></mml:msup></mml:math> resonances with masses below 3.5 and 3.8 $$\text {Te}\text {V}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mtext>Te</mml:mtext><mml:mspace/></mml:mrow></mml:math> , respectively, are excluded at 95% confidence level. In a bulk graviton model, upper limits on cross sections are set between 27 and 0.2 $$\,\text {fb}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mspace/><mml:mtext>fb</mml:mtext></mml:mrow></mml:math> for resonance masses between 1.2 and 5.2 $$\text {Te}\text {V}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mtext>Te</mml:mtext><mml:mspace/></mml:mrow></mml:math> , respectively. The limits presented in this paper are the best to date in the dijet final state.

Determination of liquid-crystal polar anchoring energy by electrical measurements
Anatoli Murauski, Vladimir G. Chigrinov, Alexander Muravsky, Fion Sze‐Yan Yeung +2 more
2005· Physical Review E42doi:10.1103/physreve.71.061707

We propose a simple method for the determination of liquid-crystal (LC) polar anchoring energy by electrical measurements. The basic idea of this method is a two-channel scheme for capacitance measurements. The first channel uses one cell with a planar LC cell, while the second a LC cell with vertical alignment. One of the LC cells can have a high pretilt angle. The proposed method allows investigating anchoring properties of both planar and vertical aligned LC materials. Simultaneous measurements of the two cells compensate all volume effects in LC bulk and provide a good opportunity to study directly the LC-surface interaction. The method can be applied for LC cells, which do not have uniform azimuthal orientation. We used this method to investigate the polar anchoring properties of photoaligning material before and after illumination and for LC structures with a high pretilt angle.

Local optical parameters of spherical polydispersions: simple approximations
Alexander Kokhanovsky, Eleanora P. Zege
1995· Applied Optics40doi:10.1364/ao.34.005513

New analytical solutions for the local optical characteristics (extinction and absorption coefficients, asymmetry parameters of phase functions) of spherical polydispersions composed of comparatively large particles are derived. The geometric optics (GO) approximation is used to solve the problem. For the accuracy of the GO approximation to be improved, the edge effects were taken into account. A comparison with the data obtained by the use of the Mie theory shows a satisfactory accuracy of our analytical formulas. The simple formulas for the cloud local optical characteristics are derived.