Browsing Zinātniskie raksti (CFI) / Scientific articles by Title

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    • Cavity Ring-Down Spectroscopy measurements of Acetone concentration 

      Revalde, G.; Alnis, J.; Blušs, K.; Grundšteins, K.; Nitšs, Edgars (Institute of Physics Publishing, 2017)
      The Cavity Ring-Down Spectroscopy system for medical applications is created and first results for detection of acetone are shown. The acetone concentration was measured in the air. In the system a pulsed 1 kHz 266 nm DPSS ...

    • Certain doping concentrations caused half-metallic graphene 

      Miao, Lu; Jia, Ran; Wang, Yu; Kong, Chui-Peng; Wang, Jian; Eglitis, Roberts I.; Zhang, Hong-Xing (Elsevier B.V., 2017)
      The singly B and N doped graphene systems are carefully studied. The highly concentrated dopants cause a spin polarization effect in the systems. The spin polarization limits are affirmed in the singly B and N doped graphene ...

    • Changes in freshwater sediment microbial populations during fermentation of crude glycerol 

      Paiders, Matiss; Nikolajeva, Vizma; Makarenkova, Galina; Orola, Liana; Dimanta, Ilze; Kleperis, Janis (Pontificia Universidad Catolica de Valparaiso, 2021)
      Background: This work studied how the exposure to an unusual substrate forced a change in microbial populations during anaerobic fermentation of crude glycerol, a by-product of biodiesel production, with freshwater sediment ...

    • Changes in structure and conduction type upon addition of Ir to ZnO thin films 

      Zubkins, Martins; Kalendarev, Robert; Gabrusenoks, Jevgenijs; Plaude, A. V.; Zitolo, Andrea; Anspoks, Andris; Pudzs, Kaspars; Vilnis, Kaspars; Azens, Andris; Purans, Juris (Elsevier B.V., 2017)
      Zn-Ir-O (Zn/Ir ≈ 1/1) thin films have been reported to be a potential p-type TCO material. It is, however, unknown whether it is possible to achieve p-type conductivity at low Ir content, and how the type and the magnitude ...

    • Chapter 8: EPR in glass ceramics 

      Antuzevics, Andris (Elsevier B.V., 2019)
      The development of novel materials requires a profound understanding of the relationship between a material's performance and its structural properties. Electron paramagnetic resonance (EPR) is a well-established technique ...

    • Characterization of CdxTeyOz/CdS/ZnO Heterostructures Synthesized by the SILAR Method 

      Suchikova, Yana; Kovachov, Sergii; Bohdanov, Ihor; Popova, Elena; Moskina, Aleksandra; Popov, Anatoli (MDPI, 2023)
      CdxTeyOz/CdS/ZnO heterostructures were obtained by the SILAR method using ionic electrolytes. A CdS film was formed as a buffer layer for better adhesion of the cadmium-tellurium oxides to the substrate surface. In turn, ...

    • Characterization of electrospun poly(lactide) composites containing multiwalled carbon nanotubes 

      Ristić, Ivan; Miletić, Aleksandra; Vukić, Nevena; Marinović-Cincović, Milena; Smits, Krisjanis; Cakić, Suzana; Pilić, Branka (SAGE Publications Inc., 2019)
      The main aim of this work was to obtain conductive polymer-based materials by incorporation of different amounts of multiwalled carbon nanotubes (MWCNTs) into poly(lactide)(PLA) using the electrospinning technique. Fiber-based ...

    • Characterization of Mechanical Oscillations in Bismuth Selenide Nanowires at Low Temperatures 

      Jasulaneca, Liga; Poplausks, Raimonds; Prikulis, Juris; Dzene, Elza; Yager, Tom; Erts, Donats (MDPIO, 2023)
      A single transistor preamplifier circuit was designed to facilitate electrical detection of mechanical oscillations in nanoelectromechanical systems (NEMSs) at low temperatures. The amplifier was integrated in the close ...

    • Characterization of Structural Stability of Magnetron Sputtered Tungsten-boron Thin Films at Elevated Temperatures 

      Avotina, Liga; Goldmane, Annija Elizabete; Vanags, Edgars; Trimdale-Deksne, Aija; Bumbure, Lada; Romanova, Marina; Sorokins, Hermanis; Muhin, Alexei; Zaslavskis, Aleksandrs; Kizane, Gunta; Dekhtyar, Yuri (Kaunas University of Technology, 2023)
      In the divertor of the tokamak type fusion reactors tungsten and tungsten-covered plasma facing materials are currently among the selected materials. However, metallic, high-Z plasma facing materials require plasma mitigation. ...

    • Chemical-state analyses of Ni, Zn, and W ions in NiWO4–ZnWO4 solid solutions by X-ray photoelectron spectroscopy 

      Bakradze, Georgijs; Kalinko, Aleksandrs; Kuzmin, Alexei (Elsevier, 2022)
      The chemical states of Ni, Zn, and W in microcrystalline NiWO4–ZnWO4 solid solutions were studied by X-ray photoelectron spectroscopy. The recorded spectra of the Ni 2p, Zn 2p, and W 4f photoelectron lines and Ni L2M23M45, ...

    • Chlorine Adsorption on TiO2(110)/Water Interface: Nonadiabatic Molecular Dynamics Simulations for Photocatalytic Water Splitting 

      Lin, Yin-Pai; Bocharov, Dmitry; Isakoviča, Inta; Pankratov, Vladimir; Popov, Aleksandr A.; Popov, Anatoli I.; Piskunov, Sergei (MDPI, 2023)
      Chloride is one of the most abundant ions in sea water, which is more available than fresh water. Due to lack of H2O adsorbate states near the valence band maximum (VBM) edge, the difficulty of water dissociation incidents ...

    • Cladding-Pumped Er/Yb-Co-Doped Fiber Amplifier for Multi-Channel Operation 

      Zakis, Kaspars; Olonkins, Sergejs; Udalcovs, Akeksejs; Lukosevics, Ingars; Prigunovs, Dmitrijs; Grube, Jurgis; Bikse, Liga; Supe, Andis; Ozolins, Oskars; Spolitis, Sandis; Bobrovs, Vjaceslavs (MDPI, 2022)
      Cladding-pumped erbium (Er3+)/ytterbium (Yb3+)-co-doped fiber amplifiers are more advantageous at high output powers. However, this amplification technique also has potential in telecom-related applications. These types ...

    • Cladding-Pumped Erbium/Ytterbium Co-Doped Fiber Amplifier for C-Band Operation in Optical Networks 

      Supe, Andis; Olonkins, Sergejs; Udalcovs, Aleksejs; Senkans, Ugis; Murnieks, Rihards; Gegere, Lilita; Prigunovs, Dmitrijs; Grube, Jurgis; Elsts, Edgars; Spolitis, Sandis; Ozolins, Oskars; Bobrovs, Vjaceslavs (MDPI, 2021)
      Space-division multiplexing (SDM) attracts attention to cladding-pumped optical amplifiers, but they suffer from a low pump power conversion efficiency. To address this issue, ytterbium (Yb3+) and erbium (Er3+) co-doping ...

    • Co-doping with boron and nitrogen impurities in T-carbon 

      Tian, Zhenwei; Cui, Xiaoqian; Tian, Jiakun; Cui, Muchen; Jin, Li; Jia, Ran; Eglitis, Roberts I. (Elsevier B.V., 2020)
      Previously, Ren et al. [Chem. Phys. 518, 69–73, 2019] reported the failure of Boron-Nitrogen (B-N) co-doping as inter B-N bond in T-carbon. In present work, a B-N atom pair is introduced in T-carbon as p-n co-dopant to ...

    • CO2 and CH2 Adsorption on Copper-Decorated Graphene: Predictions from First Principle Calculations 

      Lisovski, Oleg; Piskunov, Sergei; Bocharov, Dmitry; Zhukovskii, Yuri F.; Kleperis, Janis; Knoks, Ainars; Lesnicenoks, Peteris (MDPI, 2022)
      Single-layer graphene decorated with monodisperse copper nanoparticles can support the size and mass-dependent catalysis of the selective electrochemical reduction of CO2 to ethylene (C2 H4 ). In this study, various active ...

    • Colorimetric gas detection by the varying thickness of a thin film of ultrasmall PTSA-coated TiO2 nanoparticles on a Si substrate 

      Joost, Urmas; Šutka, Andris; Visnapuu, Meeri; Tamm, Aile; Lembinen, Meeri; Antsov, Mikk; Utt, Kathriin; Smits, Krisjanis; Nõmmiste, Ergo; Kisand, Vambola (Beilstein-Institut Zur Forderung der Chemischen Wissenschaften, 2017)
      Colorimetric gas sensing is demonstrated by thin films based on ultrasmall TiO2 nanoparticles (NPs) on Si substrates. The NPs are bound into the film by p-toluenesulfonic acid (PTSA) and the film is made to absorb volatile ...

    • Comparative ab initio calculations of reo3, srzro3, bazro3, pbzro3 and cazro3 (001) surfaces 

      Eglitis, Roberts; Purans, Juris; Gabrusenoks, Jevgenijs; Popov, Anatoli I.; Jia, Ran (MDPI AG, 2020)
      We performed, for first time, ab initio calculations for the ReO2-terminated ReO3 (001) surface and analyzed systematic trends in the ReO3, SrZrO3, BaZrO3, PbZrO3 and CaZrO3 (001) surfaces using first-principles calculations. ...

    • Comparative Hybrid Hartree-Fock-DFT Calculations of WO2-Terminated Cubic WO3 as Well as SrTiO3, BaTiO3, PbTiO3 and CaTiO3 (001) Surfaces 

      Eglitis, Roberts; Purans, Juris; Jia, Ran (MDPI, 2021)
      We performed, to the best of our knowledge, the world’s first first-principles calculations for the WO2-terminated cubic WO3 (001) surface and analyzed the systematic trends in the WO3, SrTiO3, BaTiO3, PbTiO3 and CaTiO3 ...

    • A comparative study of heterostructured CuO/CuWO4 nanowires and thin films 

      Polyakov, Boris; Kuzmin, Alexei; Vlassov, Sergei; Butanovs, Edgars; Zideluns, Janis; Butikova, Jelena; Kalendarev, Robert; Zubkins, Martins (Elsevier B.V., 2017)
      A comparative study of heterostructured CuO/CuWO4 core/shell nanowires and double-layer thin films was performed through X-ray diffraction, confocal micro-Raman spectroscopy and electron (SEM and TEM) microscopies. The ...

    • A comparative study of photocatalytically active nanocrystalline tetragonal T zyrcon- type and monoclinic scheelite-type bismuth vanadate 

      Dolić, Slobodan D.; Jovanović, Dragana J.; Smits, Krisjanis; Babić, Biljana; Marinović-Cincović, Milena; Porobić, Slavica; Dramićanin, Miroslav D. (Elsevier Ltd, 2018)
      Monoclinic scheelite-type BiVO4 is currently considered as one of the most promising non-titania photocatalysts, wheras tetragonal zircon-type BiVO4 is still poorly understood. Herein, a new and simple synthetic approach ...