«ANNUAL REPORT Riga 2012 Annual Report 2011, Institute of Solid State Physics, University of Latvia. Editor: A.Krumins. Composed matter: A.Muratova. ...»
We used LEDs as light source because they can provide necessary brightness, narrow or almost narrow spectrum with significant maximum and low power consumption properties.
LED anomaloscopes already have been provided by Woods et al , showing that this modification of device is good substitute for original Nagel anomaloscope. Our aim is to create and calibrate a power LED based anomaloscope for diagnosis of red-green colour vision defects. Other field of use of anomaloscope is a seasonal and overall variation of normal colour vision in Latvian population.
We tested two types of LEDs but no one of light sources provided necessary brightness or spectrum properties. One type of light sources produced 12-28.1 nm wide spectrum which is enough except green LEDs, because their spectrum should be about 10 nm wide. Colour mixture of available red and green primaries appeared saturated. Calculations showed retinal luminescence of 1.70- 2.30 logTd, but it is not enough for the photopic requirements. To solve the problem of brightness control - we decided to use power LEDs which can provide necessary retinal luminance. Only imperfection of these light sources is wider spectral half width. However, this can be narrowed by interference filters. The drawback of the linear potentiometer control for a control the brightness of red-green primaries is a lack of accuracy and dynamic depth. Direct control of LEDs by digital analog converter via PC serial port is an easy way. However, anomaloscope needs balanced control of primaries brightness, which could result in sophisticated schematics. To solve both problems we used microcontroller which allows to control up to 6 LEDs at same time with different PMW (pulse – width modulation) frequencies.
References  R L.Woods, A.L.Rashed, J.M.Benavides, R.H.Webb, Vision Research, 2005, 46, 3775-3781.
* In cooperation with Optometry and Vision Science Department, University of Latvia.
MULTISPECTRAL ANALYSIS OF COLOR VISION DEFICIENCY TESTS*
Color deficiency tests are usually produced by means of polygraphy technologies and help to diagnose the type and severity of the color deficiencies. Due to different factors, as lighting conditions or age of the test, standard characteristics of these tests fail, thus not allowing diagnosing unambiguously the degree of different color deficiency. Multispectral camera was used to acquire the spectral images of the Ishihara and Rabkin pseudoisochromatic plates in the visible spectrum. Multispectral color analysis was used for spectral scanning of Ishihara and Rabkin color deficiency test book images. It was done using tunable liquid-crystal LC filters built in the Nuance II analyzer. Multispectral analysis keeps both, information on spatial content of tests and on spectral content. Images were taken in the range of 420-720nm with a 10nm step.
Spectral data was converted to cone signals, and successive mathematics applied to provide a simple simulation of the test performance. Colorimetric data of the each pixel of the test image can be calculated and distribution of color coordinates is presented. We calculated retina neural activity charts taking into account cone sensitivity functions, and processed charts in order to find the visibility of latent symbols in color deficiency plates using crosscorrelation technique. In such way the quantitative measure is found for each of diagnostics plate for three different color deficiency carrier types - protanopes, deutanopes and tritanopes.
* In cooperation with Optometry and Vision Science Department, University of Latvia.
Lectures on Conferences
Latvijas Universitātes 69. konference, Rīga, 2011. gada janvāris – marts.
69th Conference of University of Latvia. Riga, Latvia, January – March, 2011.
1. Andris Šternbergs, Jānis Bērziņš. EURATOM programma Latvijā. EURATOM in Latvia.
Programma, 18. lpp.
2. A.Voitkāns, L. Dimitročenko, S. Bartling, K. Kundziņš, P. Kūlis. III grupas nitrīdu un to cieto šķīdumu nanostruktūru sintēze ar MOCVD metodi un to klasificēšana. Programma,
3. O. Vilītis, M. Rutkis, K. Kundziņš, V. Zauls. Iekārta funkcionālu nanodiegu klājumu izgatavošanai. Programma, 73. lpp.
LU Cietvielu fizikas institūta 27. Zinātniskā konference, veltīta LU Pusvadītāju fizikas problēmu laboratorijas un Salaspils Atomreaktora 50 gadu jubilejai.
Rīga, 2011. gada 14. - 16. februāris.
27th Scientific Conference, Institute of Solid State Physics, University of Latvia.
Riga, Latvia, February 14–16, 2011.
1. A.Šternbergs. ITER projekts: attīstības problēmas un risinājumi. ITER Project: Status and Development Strategy. Tēzes, 4. lpp.
2. R. Zabels, F. Muktepāvela, L. Grigorjeva, K. Kundziņš, E. Tamanis. ZnO nanokristalītu iegūšana Zn pulvera oksidēšanas ceļā. Obtaining of ZnO Nanocrystallites VIA Oxidation of Zn Powder. Tēzes, 27. lpp.
3. M. Dunce, A. Fuith, Ē. Birks, M. Antonova. Bērnsa temperatūra – noteikšana un interpretācija. Burns Temperature – Determination and Interpretation. Tēzes, 32. lpp.
4. Gvardina, A. Kristiņš, J. Melderis, J. Zvirgzds. Siltumsūkņu vadības pults. Heat Pump Control Unit. Tēzes, 38. lpp.
5. Ē. Klotiņš, A.I. Popovs, V. Pankratovs, L. Širmane, D. Engers. Polāru nanoapgabalu modelēšana Pb(Mg1/3Nb2/3)O3 (PMN). Polar Nanoregions in Pb(Mg1/3Nb2/3)O3 (PMN).
Tēzes, 50. lpp.
6. Karitāns, M. Ozoliņš, S. Fomins. Zernikes koeficientu atkarība no dažādos spektrālos apgabalos izraudzītiem atskaites stāvokļiem. Dependence of Measured Zernike Terms on the Referent State Taken at Different Regions of Spectrum. Tēzes, 73. lpp.
Piezo 2011, Electroceramics for End-users IV Sestriere, Italy, February 27 – March 03, 2011.
1. I. Smeltere, M. Antonova, M. Dunce, M. Livinsh, and B. Garbarz-Glos. Synthesis and Properties of (1-x)(K0.5Na0.5)Nb1-ySbyO3-xBaTiO3 Lead-Free Solid Solutions. Abstract P11.
Conference „Composites of Inorganic Nanotubes and Polymers“ (COINAPO), Sestriere, Italy, March 2-3, 2011,
1. M. Knite, I. Aulika, M. Dunce, A. Fuith, A. Sánchez-Ferrer, and W. Schranz. Dynamic Mechanical Analysis of Organic and Inorganic Nanotubes – Elastomer Composites.
Abstract book, p. 17.
International Conference Functional Materials and Nanotechnologies ‘FM&NT–2011’ Riga, Latvia, April 5-8, 2011.
1. J. Banys, A. Mikonis, R. Grigalaitis, V. Zauls, and A. Kania. Two Dimensional Distribution of the Relaxation Times. Book of Abstracts, p. 36.
2. G. Chikvaidze, V. Zauls, K. Kundzins, M. Kundzins, V. Ogorodniks, A. Viklsna, V.
Evteev, N. Zhandayev, V. Osokin, and V. Panibratskiy. Electron-beam Refining of UMGSi for Solar Energetics. Book of Abstracts, p. 58.
3. K. Luse, A. Pausus, V. Karitans, M. Ozolins, and M. Tukisa. Evaluation of Commercial Retroreflective Coating Performance in Decreased Visibility Conditions. Book of Abstracts, p. 100.
4. S. Fomins, M. Ozolins, G. Krumina, and I. Lacis. Analysis of Rabkin Color Deficiency Test Under Different Illumination. Book of Abstracts, p. 101.
5. V. Karitans, M. Ozolins, and K. Luse. Dependence of Wavefront Aberrations on Spectral Properties of Shack-Hartmann Wavefront Sensor. Book of Abstracts, p. 102.
6. A. Popov, V. Pankratov, D. Jakimovicha, E. Klotins, L. Shirmane, and A. Kotlov.
Luminiscence Properties of BaZrO3 Perovskites Under Synchrotron Radiation. Book of Abstracts, p. 117.
7. A. Popov, V. Pankratov, A. Lushchik, E. Klotins, L. Shirmane, V. Serga, L. Kulikova, and A. Kotlov. Comparative Study of the Luminiscence Properties of Macro and Nanocrystalline MgO Using Synchrotron Radiation. Book of Abstracts, p. 119.
8. R. Bujakiewicz-Korońska, L. Hetmanczyk, B. Garbarz-Glos, A. Budziak, A. Kalvane, and K. Bormanis. Low Temperature Measurements by Infrared Spectroscopy in CoFe2O4 Ceramic. Book of Abstracts, p. 139.
9. E. Klotins, A. Popov, and V. Pankratov. Density Functional Theory Beyond Translational Invariance: Discrete Variable Representation. Book of Abstracts, p. 168.
10. L. Dimitrocenko, K. Kundzins, A. Mishnev, I. Tale, A. Voitkans, and P. Kulis. Growth Temperature Influence on the GaN Nanowires Grown by MOVPE Technique. Book of Abstracts, p. 192.
11. R. Zabels, F. Muktepavela, L. Grigorjeva, and K. Kundzins. Effect of Nano-Powder Morphology on the Properties of ZnO Sintered Ceramics. Book of Abstracts, p. 196.
12. B. Garbarz-Glos, K. Bormanis, and M. Antonova. The Electrical Properties of BaZrxTi1xO3 Solid Solution. Book of Abstracts, p. 209.
13. Š. Svirskas, M. Ivanov, S. Bagdzevicius, J. Banys, M. Dunce, M. Antonova, E. Birks, A.
Sternberg, and V. Zauls. Dielectric Properties of 0.4Na1/2 Bi1/2 TiO3 – (0.6 – x)SrTiO3 xPbTiO3 Solid Solutions. Book of Abstracts, p. 210.
14. S. Bagdzevicius, R. Grigalaitis, J. Banys, A. Sternberg, K. Bormanis, and V. Zauls.
Dielectric Spectroscopy of 7 % Sb Doped (K0.5Na0.5)NbO3 Ceramic. Book of Abstracts, p. 212.
15. D. Sitko, W. Šmiga, B. Garbarz-Glos, K. Bormanis, and A. Kalvane. Thermal Characterization of Dielectric Properties and Ferroelectric Phase Transition in (Ba0.8Sr0.2)(Ti0.75Zr0.25)O3 Solid Solution. Book of Abstracts, p. 213.
16. J. Suchanicz, K. Pytel, K. Konieczny, A. Finder, M. Livinsh, and A. Sternberg. Effect of Electromechanical and Temperature Loading on Dielectric Properties of PLZT-x/65/35 Ceramics (x=8 and 8.5). Book of Abstracts, p. 214.
17. J. Suchanicz, I. Smeltere, A. Finder, K. Konieczny, B. Garbarz-Glos, M. Antonova, and A. Sternberg. Dielectric and Ferroelectric Properties of Lead-Free NKN and NKN-Based Ceramics. Book of Abstracts, p. 215.
18. W. Šmiga, and M. Livinsh. The Structural, Microstructural, Mechanical and Dielectric Properties of the Li0.1Na0.9NbO3 Ceramic. Book of Abstracts, p. 216.
19. I. Smeltere, M. Antonova, M. Livinsh, and B. Garbarz-Glos. Influence of BaTiO3 on Synthesis and Structure of Lead-Free Ceramics Based on KNN. Book of Abstracts, p. 217.
20. I. Smeltere, M. Livinsh, M. Antonova, A. Kalvane, and B. Garbarz-Glos. Dielectric Properties of Hot-Pressed Modified Lead Free Ceramics Based on Alkaline Niobates.
Book of Abstracts, p. 218.
21. M. Dunce, R. Taukulis, E. Birks, I. Aulika, A. Fuith, M. Antonova, and A. Sternberg.
Thermal Expansion, Burns Temperature and Electromechanical Properties in Na1/2Bi1/2TiO3-SrTiO3-PbTiO3 Solid Solutions. Book of Abstracts, p. 219.
22. M. Dunce, E. Birks, M. Antonova, M. Kundzinsh, and A. Sternberg. Relation of Dielectric Permittivity and Eectric Field Dependence of Polarization in Some Relaxors with Perovskite Structure. Book of Abstracts, p. 220.
23. K. Bormanis, A. Burkhanov, S. Mednikov, and L.T. Njan. Behaviour of the Reverse Dielectric Permeability in SBN-75 Ceramics. Book of Abstracts, p. 221.
24. M. Palatnikov, A. Frolov, E. Voinich, E.Kirkova, O. Shcherbina, N. Sidorov, and K.
Bormanis. Physical and Chemical Principles of Designing Containers for Thermochemical Treatment of High Purity Compounds of Niobium and Tantalum. Book of Abstracts, p.
25. K. Bormanis, M. Palatnikov, A. Frolov, O. Shcherbina, N. Sidorov, and V. Kalinnikov.
Ceramic Coatings of Crucibles for Thermochemical Treatment of High Purity Niobium Composites. Book of Abstracts, p. 223.
26. N. Sidorov, M. Palatnikov, P. Chufyrev, V. Kalinnikov, and K. Bormanis. Structure of Ferroelectric Lithium Niobate Single Crystals. Book of Abstracts, p. 224.
27. V. Voskresensky, O. Starodub, N. Sidorov, M. Palatnikov, K. Bormanis, V. Kalinnikov, E. Fedorova, and L. Aleshina. Computer Modelling of Cluster Formation in Ferroelectric Lithium Niobate Crystals. Book of Abstracts, p. 225.
28. N. Sidorov, M. Palatnikov, N. Tepljakova, V. Kalinnikov, and K. Bormanis. Phase Transitions in the Li0.12Na0.88TaуNb1-уO3 Solid Solution System. Book of Abstracts, p.
29. M. Palatnikov, V. Efremov, N. Sidorov, K. Bormanis, and I. Efremov. Dielectric Properties and Conductivity of Ferroelectric Li0.07Na0.93Ta0.1Nb0.9O3 and Li0.07Na0.93Ta0.111Nb0.889O3 Solid Solutions. Book of Abstracts, p. 227.
30. V. Panibratskiy, V. Osokin, M. Gadzyra, G. Chikvaidze, and V. Zauls. Application of Electron-Beam Technology for Electrical Contact Materials. Book of Abstracts, p. 249.
31. V. Panibratskiy, V. Osokin, M. Gadzyra, G. Chikvaidze, V. Zauls, and V. Solonenko.
Aspects of Silicon Oxide Reduction by Nanoscale Stoichiometric Silicium Carbide. Book of Abstracts, p. 250.
International Young Scientist Conference Developments in Optics and Communications Riga, Latvia, April 28–30, 2011.
1. K. Luse, M. Ozolins, V. Karitans, and I. Jekabsone. Effect of Position of Retroreflective Signs on Recognition of Pedestrian in Reduced Visibility Conditions. Abstracts, p. 26.
2. V. Karitans, and M. Ozolinsh. Vernier Acuity as a Function of Higher-Order Ocular Aberrations. Abstracts, p. 68.
3. S. Fomins, and U. Atvars. After-Images In Chromoluminance Space.
4. E. Skutele, and V. Karitāns. Producing of Ray Tracing Aberrometer for Studying Wavefront Deformations. Abstracts, p. 70.
5. M. Leontjeva, and G. Ikaunieks. Visual Acuity Improving With Methods Based on Perceptual Learning.
6. Z. Meskovska, and G. Ikaunieks. Effect of Straylight on Electroretinographic Response.
7. R. Trukša, and S. Fomins. Rayleight Equation Anomaloscope From Commercially Available LEDs. Abstracts, p. 86.
8. I. Zakutajeva, and S. Fomins. Wetting Angle of New and Worn Contact Lenses Identified by the Sessile Drop Technique.
International Conference and Exhibition of the European Ceramic Society (ECERS-2011), Stockholm, Sweden, June 19-24, 2011.
1. I.Smeltere, M.Antonova, M.Livinsh, and B.Garbarz-Glos. Electrical and mechanical properties of KNN based lead-free ceramics. Abstract No.103/353 (1078).
2. M. Palatnikov, O. Shcherbina, K. Bormanis, A. Frolov, N. Sidorov, and I. Smeltere.
Thermo-Resistant Ceramic Coatings of Containers for Thermo-Chemical Treatment of High Purity Niobium Compounds. Abstract No.103/1180 (2273).