Scopus İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12469/1248

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The Effect of Pyranine and Mos₂ Content on the Optical Properties of Polyacrylamide-mos₂ Composite Gels
(Taylor & Francis inc, 2024) Uysal, Bengu Ozugur; Osma, Busra; Evingur, Gulsen Akin; Pekcan, Onder
The most favorable members of the class of two-dimensional (2D) materials, molybdenum sulfide (MoS2), graphene, and tungsten disulfide (WS2) have become a thriving research frontier for many applications, ranging from catalysis to optoelectronic devices, due to their superior electronic behavior and mechanical properties. Making a new, smart, hydrogel when incorporating MoS2 into basic hydrogels can change their optical, electronic, and mechanical properties. In this work, MoS2-doped polyacrylamide (PAAm) gels were prepared via the free radical crosslinking copolymerization technique at room temperature without pyranine which is often used for crosslinking PAAm. The optical properties of PAAm-MoS2 composite gels were investigated, and they were analyzed using ultraviolet (UV) and fluorescence spectroscopy. The absorbance was measured before and after diffusion of MoS2-doped PAAm, and after the release of pyranine in and out of the composite gel, respectively. The shift of the absorption edge toward shorter wavelengths was seen when the quantity of MoS2 in the PAAm composite gels was decreased. The constituents included in the polymer composites exhibited notable photon energy absorption within the visible and ultraviolet spectra. This absorption phenomenon induced electron transitions to states of elevated energy. Parameters, such as refractive index and extinction coefficient, were analyzed with respect to the content of MoS2. When the MoS2 amount was increased in the gels, the percentage of reflectance increased. The extinction coefficient increased at longer wavelength and it decreased in the UV range, the shorter wavelength region. The results suggested that MoS2-doped PAAm composite gels show promising optoelectronic properties for developing optoelectronic devices.
Establishment of reference intervals of laboratory tests using hospital patient data
(Marmara Üniversitesi Yayınevi, 2002) Toprakçı, Mustafa; Emerk, Kaya
Objective: In this study, hospital patient data was used to derive reference intervals for selected clinical laboratory tests. Methods: Data were obtained indirectly using our hospital database including both sexes. No selection criteria have been applied. The data has been partitioned into only three age groups as, 3-20, 21-60 and 61 to older in order to prevent age related grouping in the distribution. The distributions have been checked by normality analysis using Kolmogorov-Smirnov test. Nonparametric percentile estimate method was used to obtain reference intervals in the age groups of 21-60 and 61 to older. In age group 3- 20, the number of data were below 120 in most tests so, GraphROC for Windows, a statistical package which performs a robust modified nonparametric method, was used to find reference intervals. Results: Most of the test data did not show Gaussian distribution form and parametric analysis of these data has failed. Instead, nonparametric analysis has succeeded in establishing the intervals in three age groups. Conclusion: The results resembled the characteristics of our hospital patient population. Especially, protein and lipid parameters showed clear differences in our population, compared to the reference values of the manufacturer, which are currently used. This study has been a clear evidence indicating the importance of determination of reference intervals and the analysis of indirectly selected hospital patient data using nonparametric statistical techniques.
Citation - WoS: 7
Citation - Scopus: 8
Novel Mutants of the Aubergine Gene
(Taylor & Francis Inc, 2016) Şahin, H. Bahar; Karataş, Ömer Faruk; Specchia, Valeria; Di Tommaso, Silvia D.; Diebold, Celine; Bozzetti, Maria Pia; Giangrande, Angela
Aubergine is an RNA-binding protein of the Piwi clade functioning in germline in the piRNA pathway that silences transposons and repetitive sequences. Several mutations of this gene exist but they mostly result in truncated proteins or correspond to mutations that also affect neighboring genes. We have generated complete aubergine knock-out mutants that do not disrupt the neighboring genes. These novel mutants are characterized by PCR and sequencing. Their nature is confirmed by female sterility and by the presence of crystals in testes common to the aubergine loss of function mutations. These mutants provide novel and more appropriate tools for the study of the piRNA pathway that controls genome stability.
Citation - WoS: 3
Citation - Scopus: 5
Circular Economy in the Food Systems: a Review
(Wiley, 2025) Rizwan, Danish; Kirmani, Syed Beenish Rizwan; Masoodi, Farooq Ahmad
The traditional linear economy model, characterized by the unsustainable "take-make-dispose" approach, leads to substantial resource depletion, environmental degradation, and excessive waste generation. The burgeoning need for a sustainable food system calls for a shift from the traditional open-loop linear model towards a circular economy. This review explores the transformative potential of circularity principles across various levels of food production. The closed-loop circular economy model, put forward by Walter Stahel, prioritizes efficient utilization of resources and waste minimization. It focuses on closing the loop with the food system by promoting regenerative agricultural practices, minimizing the generation of food waste and losses across the supply chain, and encouraging the valorization of waste and by-products. While acknowledging the challenges associated with this transformation, the review underscores the importance of a systematic transition. The transformation from linear to circular food systems necessitates the collective efforts of all the stakeholders, including farmers, producers, processors, retailers, and consumers. Moreover, the government and policymakers have a crucial role to play in terms of infrastructure development and crafting supportive policies to pave the way for successful transformation. By fostering educational initiatives that raise awareness about waste reduction, management, and valorization, alongside incentivizing circular economy practices, the food system can evolve into a more sustainable and closed-loop model, contributing to a more resilient future.
Citation - WoS: 3
Citation - Scopus: 3
Effect of Mos₂ on Simple and Novel Peg/Κ-carrageenan Hydrogels for Tnbc Cancer Drug Delivery
(Taylor & Francis inc, 2024) Hassan, Gana; Uysal, Bengu Ozugur
Molybdenum is a trace dietary element necessary for the survival of humans. Some molybdenum-bearing enzymes are involved in key metabolic activities in the human body (such as xanthine oxidase, aldehyde oxidase and sulfite oxidase). Many molybdenum-based compounds have been widely used in biomedical research. Especially, MoS2-nanomaterials have attracted more attention in cancer diagnosis and treatment recently because of their unique physical and chemical properties. MoS2 can adsorb various biomolecules and drug molecules via covalent or non-covalent interactions because it is easy to modify and possess a high specific surface area, improving its tumor targeting and colloidal stability, as well as accuracy and sensitivity for detecting specific biomarkers. At the same time, in the near-infrared (NIR) window, MoS2 has excellent optical absorption and prominent photothermal conversion efficiency, which can achieve NIR-based phototherapy and NIR-responsive controlled drug-release. Significantly, the modified MoS2-nanocomposite can specifically respond to the tumor microenvironment, leading to drug accumulation in the tumor site increased, reducing its side effects on non-cancerous tissues, and improved therapeutic effect. In this review, we introduced the latest developments of MoS2-nanocomposites in cancer diagnosis and therapy, mainly focusing on biosensors, bioimaging, chemotherapy, phototherapy, microwave hyperthermia, and combination therapy. Furthermore, we also discuss the current challenges and prospects of MoS2-nanocomposites in cancer treatment.
Citation - Scopus: 3
Relationship Between Dyslipidemia, C-Reactive Protein and Serological Evidence of Chlamydia Pneumoniae in Turkish Patients With Coronary Artery Diseases
(2004) Turkoglu,C.; Sonmez,E.; Aydinli,A.
Relationship between dyslipidemia, C-Reactive Protein (CRP) and serological evidence of Chlamydia pneumoniae was investigated in a Turkish population with coronary artery disease. This prospective, randomized, blinded study was carried out in Florence Nightingale Hospital which is affiliated to Kadir Has University, Medical Faculty. Thirty-two patients with acute coronary artery diseases (ACAD), 32 patients with chronic coronary artery diseases (CCAD) and 26 healthy controls (HC) were included in the study. We detected serum concentrations of C. pneumoniae IgG, IgA and IgM by ELISA method. We measured total cholesterol, trigliseride, LDL and HDL- cholesterol levels to determine dyslipidemia which was defined as total cholesterol >200 mg/dL, trigliserid > 150 mg/dl, LDL >130 mg/dL, HDL <45 mg/dL. CRP levels were also measured. Seropositivity to C. pneumoniae IgG was 84.3%, 100% and 65.3%; seropositivity to IgA was 9.3%, 6.2%, and 3.8%; and seropositivity to IgM was 12.5%, 15.3%, and 15.4% in patients with ACAD, CCAD and HC, respectively. Dyslipidemia was found as 93.7%, 78.1% and 0% of patients with ACAD, CCAD and HC, respectively. CRP level was high in all patients (ACAD, CCAD) but not in healthy controls. As a conclusion, we found a significant association between seropositivity to C. pneumoniae IgG and dyslipidemia and CRP levels in ACAD and CCAD patients (p<0.05). C. pneumoniae IgG antibodies should be evaluated together with serum lipids and CRP levels in patients with ACAD and CCAD in Turkish population. This may help clinicians in treatment of C. pneumoniae infection and decrease the risk of coronary artery diseases.
Citation - WoS: 10
Threshold-Based Steganography: a Novel Technique for Improved Payload and Snr
(Zarka Private Univ, 2016) Khan, Zakir; Shah, Mohsin; Naeem, Muhammad; Mahmood, Toqeer; Khan, Shah; Amin, Noor Ul; Shehzad, Danish
Steganography is the art of hiding user information in various file types including image audio and video. Security of steganography lies in imperceptibility of secret information in the cover image. Human Visual System (HVS) is not able to detect the changes in low color values of an image. To the best of our knowledge none of the available steganographic techniques have exploited this weakness of HVS. In this paper a new LSB technique is presented which hides information in the cover image taking into account the pixel value of color or grey level of every pixel. Our experiments show that the proposed technique has a high payload and low perceptibility of secret information hidden in the cover image as compared to the existing Least Significant Bit (LSB) based algorithms. We have used MATLAB for the implementation of proposed algorithm.
Citation - WoS: 3
Citation - Scopus: 2
Em Based Stochastic Maximum Likelihood Approach for Localization of Near-Field Sources in 3-D
(Walter De Gruyter Gmbh, 2004) Kabaoğlu, Nihat; Çırpan, Hakan Ali; Paker, Selçuk
The goal of this paper is to estimate the locations of unknown sources in 3-D space from the data collected by a 2-D rectangular array. Various studies employing different estimation methods under near-field and far-field assumptions were presented in the past. In most of the previous studies location estimations of sources at the same plane with the antenna array were carried out by using algorithms having constraints for various situations indeed. In this study location estimations of sources that are placed at a different plane from the antenna array is given. In other words locations of sources in 3-D space is estimated by using a 2-D rectangular array. Maximum likelihood (ML) method is chosen as the estimator since it has a better resolution performance than the conventional methods in the presence of less number and highly correlated source signal samples and low signal to noise ratio. Besides these superiorities stability asymptotic unbiasedness asymptotic minimum variance properties as well as no restrictions on the antenna array are motivated the application of ML approach. Despite these advantages ML estimator has computational complexity. However this problem is tackled by the application of Expectation/Maximization (EM) iterative algorithm which converts the multidimensional search problem to one dimensional parallel search problems in order to prevent computational complexity. EM iterative algorithm is therefore adapted to the localization problem by the data (complete data) assumed to arrive to the sensors separately instead of observed data (incomplete data). Furthermore performance of the proposed algorithm is tested by deriving Cramer-Rao bounds based on the concentrated likelihood approach. Finally the applicability and effectiveness of the proposed algorithm is illustrated by some numerical simulations.
Citation - WoS: 1
Citation - Scopus: 2
A New Design of a 3 X 3 Reversible Circuit Based on a Nanoscale Quantum-Dot Cellular Automata
(World Scientific Publ Co Pte Ltd, 2023) Liu, Ling-Li; Navimipour, Nima Jafari
Quantum-dot cellular automata (QCA) is the best-suggested nanotechnology for designing digital electronic circuits. It has a higher switching frequency, low-power expenditures, low area, high speed and higher scale integration. Recently, many types of research have been on the design of reversible logic gates. Nevertheless, a high demand exists for designing high-speed, high-performance and low-area QCA circuits. Reversible circuits have notably improved with developments in complementary metal-oxide-semiconductor (CMOS) and QCA technologies. In QCA systems, it is important to communicate with other circuits and reversible gates reliably. So, we have used efficient approaches for designing a 3 x 3 reversible circuit based on XOR gates. Also, the suggested circuits can be widely used in reversible and high-performance systems. The suggested architecture for the 3 x 3 reversible circuit in QCA is composed of 28 cells, occupying only 0.04 mu m(2). Compared to the state-of-the-art, shorter time, smaller areas, more operational frequency and better performance are the essential benefits of the suggested reversible gate design. Full simulations have been conducted with the utilization of QCADesigner software. Additionally, the proposed 3 x 3 gate has been schematized using two XOR gates.
Citation - WoS: 12
Citation - Scopus: 15
Accurate Refinement of Docked Protein Complexes Using Evolutionary Information and Deep Learning
(Imperıal College Press, 2016) Akbal-Delibas, Bahar; Farhoodi, Roshanak; Pomplun, Marc; Haspel, Nurit
One of the major challenges for protein docking methods is to accurately discriminate native-like structures from false positives. Docking methods are often inaccurate and the results have to be refined and re-ranked to obtain native-like complexes and remove outliers. In a previous work we introduced AccuRefiner a machine learning based tool for refining protein-protein complexes. Given a docked complex the refinement tool produces a small set of refined versions of the input complex with lower root-mean-square-deviation (RMSD) of atomic positions with respect to the native structure. The method employs a unique ranking tool that accurately predicts the RMSD of docked complexes with respect to the native structure. In this work we use a deep learning network with a similar set of features and five layers. We show that a properly trained deep learning network can accurately predict the RMSD of a docked complex with 1.40 angstrom error margin on average by approximating the complex relationship between a wide set of scoring function terms and the RMSD of a docked structure. The network was trained on 35000 unbound docking complexes generated by RosettaDock. We tested our method on 25 different putative docked complexes produced also by RosettaDock for five proteins that were not included in the training data. The results demonstrate that the high accuracy of the ranking tool enables AccuRefiner to consistently choose the refinement candidates with lower RMSD values compared to the coarsely docked input structures.
Citation - WoS: 1
Citation - Scopus: 3
Processor Design and Application of Futuristic
(Univ Nis, 2025) Misra, Neeraj Kumar; Pathak, Nirupma; Bhoi, Bandan Kumar; Ahmadpour, Seyed-Sajad; Kassa, Sankit R.; Navimipour, Nima Jafari
Many devices consist of low-power processor. Quantum-dot-cellular-automata (QCA) based processor designs provide enhanced performance compared with conventional metal-oxide-semiconductor (MOS) based processors. Nanocomputing-based processors are often energy-efficient. We have developed Nanotechnology QCA-based different subcomponents of processor such as 2-to-4 decoder, 3-to-8 decoder, Delay Flip-flop (D-FF), and sequence counter. A potential energy proof has been measured in the 2-to-4 decoder design. The synthesis approach algorithm has been presented for all designs. Further, the potential energy calculation results show for 2-to-4 decoder. According to the synthesis results 2-to-4 decoder has improved 82.3% cell count, 86% area, and 85% latency over previous work. Comparing the primitive results with the prior one, results improved by 64% and 76% in terms of cell count and area in the design of the 3-to-8 decoder. Among the different components of the processor is D-FF, which has an improvement of 66.37% in cell counts and 62.5% in area over the prior design. Primitive results have improved, including latency, cell count, and area, showing the proposed processor design is comparable to lowpower devices and high speed. In terms of balance power, the proposed subcomponent of the processor will benefit low power device.
Women's Snap Judgments for Incompatible Facial and Vocal Cues
(Hogrefe Publishing GmbH, 2024) Harma, M.; Kuru, E.D.
There has been a paucity of studies exploring the combined impact of facial and vocal cues on attractiveness and trustworthiness evaluations. We examined the concurrent evaluation of attractiveness and trustworthiness when facial and vocal cues were incompatible, such as attractive faces with unattractive voices. We collected data from women participants aged between 20 and 33 years (N = 127, M = 22.19, SD = 2.34). Results revealed that participants evaluated attractive faces with unattractive voices as more attractive, compared to unattractive faces with attractive voice combinations. Moreover, trustworthiness evaluations showed different patterns; participants rated untrustworthy faces with trustworthy voices higher on trustworthiness than trustworthy faces with untrustworthy voice combinations. These findings support the notion that different cues (facial and vocal) play divergent roles in snap judgments. © 2025 Hogrefe Publishing.
Measurement of Oxygen Diffusion in Ps/Pnipam Films Using Fluorescence Quenching
(Taylor & Francis Ltd, 2015) Yargı, Önder; Pekcan, Önder; Uğur, Şaziye
The diffusion of oxygen into pyrene labelled polystyrene (PS) latex/poly(N-isopropylacrylamide) (PNIPAM) composite films (PS/PNIPAM) was studied based on PS content with the use of fluorescence quenching method. Fluorescence experiments were carried out on composite films containing pyrene as a sensor dye. The Stern-Volmer equation for fluorescence quenching is combined with Fick's law for diffusion to derive mathematical expressions. Diffusion coefficients (D) were produced and found to be decreased with increasing PS content. This decrease was explained with the formation of a tortuous path for diffusing gas molecules which extends the diffusion path of oxygen in the films. In addition at high PS content two different D values were obtained which were attributed to the existence of two different areas in the composite films.
Effects of Straits on Hydro-Thermal Performance of Small Bays
(Turkish Chamber Civil Engineers, 2019) Ger, Ahmet Metin
The heated surface jet discharged into a bay which is connected to a larger body of water through a strait may experience bifurcation in the bay and stratification in the strait. The combined effects of bifurcation and stratification may lead to a substantially greater rise in temperature than the rise expected in case of unrestricted receiving body of water. In this study, the behavior of heated effluents discharged into bays with a restricted access to a large body of water is scrutinized experimentally by the help of a scaled physical model. Dimensional analysis leads to a new dimensionless parameter A(r), area restriction parameter, on which the difference between the excess temperatures at the inlet of the strait for restricted and free receiving mediums, Delta(Delta T/Delta T-0) is shown to be strongly dependent.
Epidemic Models for Chemical Gel Phase Transformation: Effect of Optical Measurements With Different Wavelengths
(Taylor & Francis Inc, 2023) Ogrenci, Arif Selcuk; Bilge, Ayse Humeyra; Pekcan, Onder; Incegul, Metehan
In our previous work we characterized the sol-gel transition of chemical and physical gels in terms of epidemic models which describe the spread of a disease in a society. We have shown that gelation in chemical gels can be represented by the Susceptible-Infected-Recovered (SIR) model, while the gelation mechanism of physical gels can be represented by the Susceptible-Infected-Susceptible (SIS) model. These studies were based on optical measurements at a single wavelength. In the present work we studied the gelation mechanism for chemical gels obtained from experiments that have been carried out with acrylamide (AAm) and N,N0-methylenebis (acrylamide) (Bis) as base materials for chemical gel formation in water and with cross-linker. The transmitted light intensity was measured for various wavelengths from 440 nm to 690 nm during the gelation process. The data are modeled by the epidemic SIR process. The results indicate that the gelation processes obtained from the same Bis and water contents observed at different wavelengths obey different SIR models. This observation is explained by the scattering of light of different wavelengths depending on the sizes of the micro-gels formed.
Citation - WoS: 21
Citation - Scopus: 23
A Nano-Design of a Quantum-Based Arithmetic and Logic Unit for Enhancing the Efficiency of the Future Iot Applications
(Aip Publishing, 2025) Ahmadpour, Seyed Sajad; Zaker, Maryam; Navimipour, Nima Jafari; Misra, Neeraj Kumar; Zohaib, Muhammad; Kassa, Sankit; Hakimi, Musawer
The Internet of Things (IoT) is an infrastructure of interconnected devices that gather, monitor, analyze, and distribute data. IoT is an inevitable technology for smart city infrastructure to ensure seamless communication across multiple nodes. IoT, with its ubiquitous application in every sector, ranging from health-care to transportation, energy, education, and agriculture, comes with serious challenges as well. Among the most significant ones is security since the majority of IoT devices do not encrypt normal data transmissions, making it easier for the network to breach and leak data. Traditional technologies such as CMOS and VLSI have the added disadvantage of consuming high energy, further creating avenues for security threats for IoT systems. To counter such problems, we require a new solution to replace traditional technologies with a secure IoT. In contrast to traditional solutions, quantum-based approaches offer promising solutions by significantly reducing the energy footprint of IoT systems. Quantum-dot Cellular Automata (QCA) is one such approach and is an advanced nano-technology that exploits quantum principles to achieve complex computations with the advantages of high speed, less occupied area, and low power consumption. By reducing the energy requirements to a minimum, QCA technology makes IoT devices secure. This paper presents a QCA-based Arithmetic Logic Unit (ALU) as a solution to IoT security problems. The proposed ALU includes more than 12 logical and arithmetic operations and is designed using majority gates, XOR gates, multiplexers, and full adders. The proposed architecture, simulated in QCADesigner 2.0.3, achieves an improvement of 60.45% and 66.66% in cell count and total occupied area, respectively, compared to the best of the existing designs, proving to be effective and efficient.
Citation - Scopus: 1
CHAOTIC – DETERMINISTIC OR RANDOM NATURE OF EARTHQUAKES: A PHASE SPACE ANALYSIS
(Symmetrion, 2023) Pekcan,O.; Arsan,T.
Using the phase space approach, time series analysis of high EV1 and low EV2 intense two different earthquakes that occurred at the nearly same precise spot, at different times, and were measured with the same sensor of a broadband station were studied. Time series data of strong, large (EV1) and weak, small (EV2) two earthquake events were analyzed by dividing them into three different regions. Fractal dimensions of the EV1 and EV2 were produced using the box-counting algorithm for east-west (BHE), north-south (BHN), and vertical (BHZ) components. The small, weak earthquake, EV2, created a larger fractal dimension in phase space by implying its random nature in all regions. However, EV1 is a strong, large earthquake that presents deterministic oscillatory behavior at a long-time region. Oscillatory behavior can be named surface wave. EV2 exhibits weak, high-frequency ground oscillations similar to fibrillation before and after the earthquake in the long-term areas. © 2023, Symmetrion. All rights reserved.
Citation - Scopus: 9
Energy in Turkey and Russia’s Roller-Coaster Relationship
(SETA, 2017) Ediger,V.Ş.; Durmaz,D.
Energy relations between Turkey and Russia provide an excellent example of how energy and politics interrelate in countries with a historically up-and-down relationship. Having started in the 1960s, the two countries’ energy relations gained a new dimension after 1991 with the intensification of pipeline politics. In the 2000s, energy relations gained impetus owing to the leadership of Erdoğan and Putin, and reached an apex with the establishment of a cooperation council in 2010. Since 2011, Turkey’s demands for gas price reduction and volume increase have dominated the agenda of the countries’ energy talks. While Turkish-Russian relations have remained on shaky ground lately, the signing of the Turkish Stream agreement in 2016 might be perceived as a positive step for closer energy relations. © 2017, SETA. All rights reserved.
Citation - Scopus: 3
Forecasting Us Movies Box Office Performances in Turkey Using Machine Learning Algorithms
(IOS Press BV, 2020) Çaǧliyor,S.; Öztayşi,B.; Sezgin,S.
The motion picture industry is one of the largest industries worldwide and has significant importance in the global economy. Considering the high stakes and high risks in the industry, forecast models and decision support systems are gaining importance. Several attempts have been made to estimate the theatrical performance of a movie before or at the early stages of its release. Nevertheless, these models are mostly used for predicting domestic performances and the industry still struggles to predict box office performances in overseas markets. In this study, the aim is to design a forecast model using different machine learning algorithms to estimate the theatrical success of US movies in Turkey. From various sources, a dataset of 1559 movies is constructed. Firstly, independent variables are grouped as pre-release, distributor type, and international distribution based on their characteristic. The number of attendances is discretized into three classes. Four popular machine learning algorithms, artificial neural networks, decision tree regression and gradient boosting tree and random forest are employed, and the impact of each group is observed by compared by the performance models. Then the number of target classes is increased into five and eight and results are compared with the previously developed models in the literature. © 2020 - IOS Press and the authors. All rights reserved.
Citation - Scopus: 1
Determination of Growth Kinetics and Size Dependent Structural Morphological Optical Characteristics of Sol-Gel Derived Silica Nanoparticles in Silica Matrix
(De Gruyter Poland Sp Zoo, 2019) Uysal, Bengü Özuğur; Tepehan, Fatma Zehra
Nanocomposite silica thin films made using the sol-gel method were studied. The nano-silica films were prepared using a mixture of tetraethyl orthosilicate (TEOS) deionized water ethanol and ammonia solution. To control the growth of the particles inside the film the nanocomposite silica film was prepared using a mixture of the nano-silica sol and the silica sol. The change in the particle size with the heat treatment temperature ranging from 450 degrees C to 1100 degrees C was investigated. X-ray diffraction (XRD) atomic force microscopy (AFM) scanning electron microscopy (SEM) NKD (refractive index-N extinction coefficient-K and thickness-D) and ultraviolet-visible (UV-Vis) spectrophotometry were used for characterization purposes. The XRD studies showed that the nano-silica thin films were amorphous at all annealing temperatures except for 1100 degrees C. The alpha-cristobalite crystal structure formed at the annealing temperature of 1100 degrees C. Optical parameters such as refractive indices and extinction coefficients were obtained using the NKD analyzer with respect to the annealing temperature of the films. The activation energy and enthalpy of the nanocomposite silica film were evaluated as 22.3 kJ/mol and 14.7 kJ/mol respectively. The cut-off wavelength values were calculated by means of extrapolation of the absorbance spectra estimated using the UV-Vis spectroscopy measurements. A red shift in the absorption threshold of the nanocomposite silica films indicated that the size of the silica nanoparticles increased with an increase of the annealing temperatures from 450 degrees C to 900 degrees C and this confirms the quantum confinement effect in the nanoparticles.

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