Araştırmacılar(5)

• Ak, Ayşe
• Çayır Taşdemirci, Tuba
• Karakaş, Mehmet Fatih
• Orbay, Sinem
• T.Çayir

• ArticleYayıncıda açık erişim2026/r/ebyu/19286
  Decoding brain signals for inner speech: eeg signal sub-band decomposition and machine learning approach

  Karakas, Mehmet Fatih

  Decoding inner speech is a rapidly advancing field with significant implications for brain-computer interfaces (BCIs) and assistive technologies. In this study how sub-band decomposition, feature types, and classifier choice affect inner-speech classification were assessed. A comprehensive comparative framework is presented, employing various sub-band decomposition techniques including Tunable Q-Factor Wavelet Transform, Empirical Mode Decomposition, Variational Mode Decomposition, and Circulant Singular Spectrum Analysis. From the decomposed signals, 17 statistical, 4 entropy, and 5 frequency features were extracted individually and in hybrid combinations before reduction with Least Absolute Shrinkage and Selection Operator. Classification performance was evaluated with 10-fold cross-validation, using Support Vector Machine, Feedforward Neural Network, and K-Nearest Neighbor. Performance was summarized as the mean across 30 independent runs per condition over six metrics. A three-way repeated measures ANOVA with Greenhouse-Geisser correction showed significant main effects and interactions across all metrics (p < 0.001), with large effect sizes (η2p >= 0.14). The best overall configuration was EMD-Hybrid-SVM outperforming baseline models, yielding a group-level mean accuracy of 54.13%. These findings demonstrate the potential of sub-band decomposition and hybrid features for improving inner speech decoding and contribute to the development of more robust EEG-based BCIs.

  RDL Kalıcı Kaydıİncele
• ArticleYalnız künye2026/r/ebyu/10989
  Influence of Film Thickness on the Structural, Optical, and Electrical Properties of CdO Thin Films Grown via the SILAR Method

  Çayır Taşdemirci, Tuba

  Herein, the successive ionic layer adsorption and reaction method was used to synthesize cadmium oxide (CdO) with excellent optical and electrical properties at room temperature. Four thin films of varying thicknesses were grown and analyzed for their optical, structural, and electrical properties. X-ray diffraction (XRD), scanning electron microscopy-coupled energy-dispersive X-ray spectroscopy, and atomic force microscopy were used to examine the structural properties of the CdO thin films, while ultraviolet–visible spectroscopy assessed their optical properties. The two-point probe method was used to investigate the electrical properties of these films. The results indicated that increasing the CdO film thickness led to increased peak intensities in their XRD patterns, indicating an improvement in the crystal structure. In addition, the energy bandgap of these films increased from 1.97 to 2.6 eV with increasing film thickness.

  RDL Kalıcı Kaydıİncele
• ArticleAçık Erişim2026/r/ebyu/10875
  Effect of annealing temperature on bismuth oxide semiconductor thin films grown by RF sputtering at different powers

  Taşdemirci, Tuba Çayir

  Bi₂O₃ thin films were deposited on glass substrates using RF magnetron sputtering at 80, 100, and 120 W, and the effects of post-annealing at 200 °C and 300 °C were investigated. XRD results show that all films crystallize in the monoclinic α-Bi2O3 phase, with the (–112) plane becoming increasingly dominant as annealing temperature increases. Grain size increases while dislocation density and microstrain decrease with both higher sputtering power and annealing, indicating improved crystallinity. SEM analyses reveal homogeneous spherical grains in unannealed films, which transform into smoother surfaces or rod-like structures after annealing, depending on the sputtering power. EDAX confirms increased oxygen incorporation with rising annealing temperature. UV–Vis spectroscopy shows a systematic reduction in optical band gap with annealing, from 3.57 to 3.38 eV (80 W), 3.29 to 3.08 eV (100 W), and 2.88 to 2.79 eV (120 W). Overall, thermal treatment significantly enhances structural quality and tunes the optical properties of Bi2O3 thin films, making them suitable for optoelectronic and sensing applications.

  RDL Kalıcı Kaydıİncele
• CorrectionYayıncıda açık erişim2026/r/ebyu/10566
  Publisher Correction: Characterization of SnO2 Thin Films deposited with SILAR: Effect of Annealing on Physical Properties (Brazilian Journal of Physics, (2026), 56, 4, (168), 10.1007/s13538-026-02087-7)

  Taşdemirci, Tuba Çayır

  During the correction process, parts of Fig. 4 were inadvertently deleted. Following is the complete figure: (Figure presented.) Fig. 4 SEM-EDAX images of SnO2 thin films as grown, annealed at 250 °C, 300 °C and 350 °C

  RDL Kalıcı Kaydıİncele
• ArticleYalnız künye2026/r/ebyu/10209
  Characterization of SnO2 Thin Films deposited with SILAR: Effect of Annealing on Physical Properties

  Çayır Taşdemirci, Tuba

  SnO₂ thin films were deposited on glass substrates using the SILAR method at room temperature and subsequently annealed at 250 °C, 300 °C, and 350 °C for 30 min. The structural, morphological, and optical properties of the as-grown and annealed films were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive X-ray analysis (EDAX), atomic force microscopy (AFM), and UV–Vis spectroscopy. XRD analysis revealed that increasing the annealing temperature improved crystallinity, enhanced peak intensities, and promoted the formation of the rutile SnO₂ phase. SEM and AFM analyses showed that annealing led to grain growth and smoother film surfaces. EDAX confirmed the presence of Sn and O elements, while the Si signal from the substrate decreased at higher annealing temperatures due to improved surface coverage. UV–Vis measurements indicated a reduction in optical band gap from 3.53 eV (as-grown) to 3.21 eV (350 °C), attributed to enhanced crystallinity and reduced structural defects. The results of this study demonstrate the strong influence of annealing temperature on the structural and optical performance of SILAR-grown SnO₂ thin films, which directly determines their suitability for optoelectronic devices. The enhanced crystallinity and increased crystallite size observed after annealing improve charge carrier mobility by reducing grain boundary scattering. This is particularly beneficial for applications such as transparent conducting electrodes, gas sensors, and thin-film transistors, where high electrical conductivity and structural order are essential.

  RDL Kalıcı Kaydıİncele
• ArticleYayıncıda açık erişim2025/r/ebyu/19450
  Impact of Annealing Temperature on Physical Properties of Manganese Sulfide Thin Film

  Taşdemirci, Tuba Çayır

  MnS thin films were grown on glass substrates at room temperature using the SILAR method, which is simple, easy to apply, and cheap. The grown thin films were annealed at 150, 200, 250, and 3000C for 30 minutes, respectively. The structural and optical properties of the obtained thin films were examined. XRD and SEM analyses were performed for structural properties, and UV-Vis analyses were performed for optical properties. Based on the results, it can be concluded that the annealing temperature has a positive impact on the structural and optical properties of MnS thin films.

  RDL Kalıcı Kaydıİncele
• CorrectionYalnız künye2025/r/ebyu/12234
  Corrigendum to “Molecularly imprinted polymers for the detection of volatile biomarkers” [Trends Anal. Chem. 177 (2024) 117783] (Trends in Analytical Chemistry (2024) 177, (S0165993624002668), (10.1016/j.trac.2024.117783))

  Wasilewski, Tomasz; Orbay, Sinem; Brito, Nathália F.; Sikora, Karol; Melo, Ana Claudia A.; Melendez, Matias E.; Szulczyński, Bartosz; Sanyal, Amitav; Kamysz, Wojciech; Gębicki, Jacek

  The authors regret the incorrect attribution of affiliation for one of the authors of the manuscript. In the original manuscript, the affiliation for Bartosz Szulczyński was incorrectly denoted with the letter g. The correct affiliation for Bartosz Szulczyński is: Department of Process Engineering and Chemical Technology, Chemical Faculty, Gdańsk University of Technology, Narutowicza 11/12, Gdańsk, 80–233, Poland, denoted with the letter f. The authors would like to apologise for any inconvenience caused.

  RDL Kalıcı Kaydıİncele
• ArticleYalnız künye2025/r/ebyu/11546
  Fabrication of CdO thin films with SILAR: Influence of annealing temperature on physical properties

  Taşdemirci, Tuba Çayir

  Cadmium oxide (CdO) thin film was grown on a glass substrate at room temperature using the Successive ionic layer adsorption and reaction (SILAR) method. The grown thin films were annealed at 3500C and 4000C for 30 min. Structural and optical properties of CdO thin films after annealing were examined. Analyzes were made with X-ray diffractometer (XRD) and Scanning electron microscope-Energy dispersive X-ray spectroscopy (SEM-EDAX) devices for structural properties, and UV–Vis devices for optical properties. The XRD peak intensities of CdO thin films exposed to annealing temperature increased and the crystal structure improved. The bandgap energy range decreased from 2.48 eV to 2.37 eV with the effect of annealing temperature.

  RDL Kalıcı Kaydıİncele
• ArticleAçık Erişim2025/r/ebyu/11527
  Synthesis of MnS thin film: investigation of thickness-dependent physical properties

  Çayir Taşdemirci, Tuba

  Herein, manganese sulfide (MnS) thin films are grown on glass substrates using the successive ionic layer adsorption and reaction (SILAR) method. SILAR is simple and inexpensive, does not require a high-quality substrate or vacuum environment, has no limitation on the size of the substrate material, has the ability to obtain materials at room temperature, shows easier doping process relative to other methods, and has the ability to control the growth rate and thickness of films. MnS with different thicknesses is coated on a glass surface, and various analyses are performed to examine the effect of the thickness on the film properties. Ultraviolet–visible analysis is used to examine the optical properties of the film, X-ray diffraction (XRD) spectrometry to examine its structural properties, and scanning electron microscopy and atomic force microscopy (AFM) to examine its morphological properties. XRD results indicate that the obtained MnS thin films have a cubic structure and achieve the highest peak intensity at 2θ = 32.87°. With increasing film thickness, the grain size increases from 9.20 to 13.36 nm and the energy band gap decreases from 3.32 to 3.02 eV. AFM results demonstrate that with increasing film thickness, the surface roughness value decreases from 84 to 53 nm. Moreover, increasing thickness improves the optical, structural, and morphological properties of the film.

  RDL Kalıcı Kaydıİncele
• ArticleYalnız künye2025/r/ebyu/11504
  SILAR growth of pure CdO and copper-doped CdO thin films: Structural, optical and electrical properties

  Çayir Taşdemi̇rci̇, Tuba

  This study explores the effects of copper (Cu) doping on the structural and optical properties of cadmium oxide (CdO) thin films, which are widely employed in optoelectronic applications. CdO thin films were synthesized using the Successive Ionic Layer Adsorption and Reaction (SILAR) method on glass substrates, followed by doping with CuO at varying concentrations. The resulting films were characterized using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDAX), and UV–Vis spectroscopy. XRD results revealed a cubic polycrystalline structure for both undoped and Cu-doped films. SEM analysis indicated a morphological shift from spherical to flower-like structures with increased Cu content, supported by elemental analysis via EDAX. Particle size distribution was calculated using SEM images. Optical studies showed a progressive decrease in the energy band gap from 2.48 eV (undoped CdO) to 1.99 eV (highest Cu doping level), highlighting the potential for tuning the electronic properties of CdO films through Cu doping. When the electrical properties of CdO and Cu-doped CdO thin films were examined, it was found that Cu doping decreased the resistivity. These findings demonstrate the effectiveness of Cu doping in enhancing the optoelectronic characteristics of CdO thin films for advanced device applications.

  RDL Kalıcı Kaydıİncele