Elena Koleva

20140506-46
Study of Electron Beam Resists: Negative Tone HSQ and Positive Tone SML300
Ivan Kostic, Anna Bencurova, Anna Konecnikova, Pavol Nemec, Adrian Ritomsky, Elena Koleva, Katia Vutova, Georgi Mladenov

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In this paper the contrast and sensitivity characteristics are investigated concerning the negative tone electron beam resist HSQ (hydrogen silsesquioxane) and the positive tone SML300 electron beam organic resist, designed ...  read more

20140506-36
Optical and Structural Investigations of WOx Thin Films Deposited by Electron Beam Evaporation Process
Katia Vutova, Vania Vassileva, Alexander Stoimenov, Elena Koleva, Tatyana Ivanova, Georgi Bodurov, Kostadinka Gesheva, Georgi Mladenov

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Thin films of tungsten oxide are obtained at different technological parameters using electron beam evaporation process. Their optical and structure properties are investigated and the relation with process parameters is discussed. ...  read more

20140506-13
Model-Based Quality Optimization of EBW of steel
Elena Koleva, Dmitriy Trushnikov, Vladimir Belenkiy, Georgi Mladenov, Stefan Angelov, Dimitar Todorov

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Experimental results (four series of experiments) for EBW of two types of steel – high strength steel of 38Cr2Ni2Mo type and stainless steel are obtained and used for the estimation of models, describing the dependencies ...  read more

20140506-07
Electron Beam Characterization at Changes of EBW Process Parameters
Elena Koleva, Georgi Mladenov, Marin Kardjiev, Dimitar Todorov

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The characterization of the radial and the angular space distribution of particle trajectories (or respective current distributions) in powerful electron beams is an actual scientific and practical task, connected with the ...  read more

20140506-04
Control of Electron Beam Welding of Plates, Using Current of the Back Plate Side
Elena G. Koleva, Dmitriy N. Trushnikov, Vladimir Ya. Belenkiy, Georgi M. Mladenov

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The conventional systems for control of throughout welds used beam current, that is passing through the crater in the liquid metal to the space on the back side of sample. In this paper a collector, situated not opposite the ...  read more

20140506-03
Ion Current, Collected from Plasma above the Welding Zone during Electron Beam Welding
Dmitriy N. Trushnikov, Georgi M. Mladenov, Vladimir Ya.Belenkiy, Elena G. Koleva

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Measurements of fluctuations of the ion current, collected by the plasma, generated during electron beam welding and treatment of the acquired data with modern digital methods are executed. Through the application of Coherent ...  read more

20180708-13
Modelling of E-beam crosslinking of composite hydrogels
Maria Demeter, Ion Călina, Cătălin Vancea, Toni P. Paneva, Elena G. Koleva, Lilyana St. Koleva

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Response Surface Methodology and robust engineering approach were applied for the investigation of preliminary experimental data related to the synthesis of composite biopolymer-based hydrogels via electron beam (e-beam) radiation ...  read more

20160506-48
Graphical user interface for optimization of starch modified by electron beam irradiation
Elena G. Koleva, Lilyana St. Koleva, Mirela Braşoveanu, Monica R. Nemţanu, Toni P. Paneva, Ventzislav K. Tzotchev

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Experimental investigation of electron beam induced graft copolymerization of starch (corn and potato), using electron beam generated by a linear accelerator with energy of 5.5 MeV and 6.23 MeV is performed. The modification ...  read more

20160506-42
Resist characteristics simulation of HSQ electron beam resist
Anna Bencurova, Katia Vutova, Elena Koleva, Ivan Kostic, Anna Konecnikova, Adrian Ritomsky, Georgi Mladenov

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Hydrogen Silsesquioxane (HSQ) is used as a high-resolution resist with resolution down below 10 nm half-pitch. High-contrast and high-resolution patterning in the negative electron beam HSQ resist has numerous potential applications. ...  read more

20160506-31
Emittance – quantitative characteristic of welding beam quality
Elena Koleva, Georgi Mladenov, Volodya Dzharov, Dimitar Todotov, Marin Kerdjiev, Lilyana Koleva

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The management of the quality during electron beam welding directed to optimization of the process parameters is an important way to improve the use of the expensive equipment and to make the EBW process more efficient in consuming materials, time and energy.

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