| 1. |
- Aad, G., et al.
(author)
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- 2012
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swepub:Mat__t (peer-reviewed)
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| 2. |
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| 3. |
- ÖZEN, MUSTAFA, 1984, et al.
(author)
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Symmetrical Doherty Power Amplifier With Extended Efficiency Range
- 2016
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In: IEEE Transactions on Microwave Theory and Techniques. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9480 .- 1557-9670. ; 64:4, s. 1273-1284
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Journal article (peer-reviewed)abstract
- A symmetrical Doherty power amplifier (PA) with an extended efficiency range is proposed. This paper proves the existence of a class of symmetrical Doherty PAs having efficiency peaks for back-off levels larger than 6 dB. A design technique is developed that maintains the full voltage and current swings of both the main and auxiliary transistors. The concept is experimentally verified in a 1.95-GHz 25-W circuit demonstrator fabricated using identical GaN HEMT devices. An average power-added efficiency of 50% and adjacent power leakage ratio of -49 dBc is obtained with 9-dB peak-to-average power-ratio 20-MHz long-term evolution test signals.
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| 4. |
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| 5. |
- Özeren, Hüsamettin Deniz, et al.
(author)
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Ranking Plasticizers for Polymers with Atomistic Simulations; PVT, Mechanical Properties and the Role of Hydrogen Bonding in Thermoplastic Starch
- 2020
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In: ACS Applied Polymer Materials. - : American Chemical Society (ACS). - 2637-6105. ; 2:5, s. 2016-2026
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Journal article (peer-reviewed)abstract
- Virgin biopolymers are often brittle and, therefore, need the addition of plasticizers to obtain the required mechanical properties for practical applications, e.g. in bags and disposable kitchen items. In this article, based on a combined experimental and modelling approach, it is shown that it is possible to rank molecules with respect to their plasticization efficiency (depression in glass transition temperature with PVT data and reduced stiffness and strength) using molecular dynamics simulations. Starch was used as the polymeric matrix material due to its promising potential as a sustainable, eco-friendly, biobased replacement for fossil-based plastics. Three polyols (glycerol, sorbitol and xylitol), two ethanolamines and glucose were investigated. The results indicate that molecular simulations can be used to find the optimal plasticizer among a set of candidates, or to design/identify better plasticizers in a complex polymer system. Glycerol was the most efficient of the six plasticizers, explained by it forming the least amount of hydrogen bonds, having the shortest hydrogen bond lifetimes and low molecular rigidity. Hence, not only was it possible to rank plasticizers, the ranking results could also be explained by the simulations.
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| 6. |
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| 7. |
- Özel, Fatih, et al.
(author)
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DNA methylation at DLGAP2 and risk for relapse in alcohol dependence during acamprosate treatment
- 2024
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In: Drug And Alcohol Dependence. - : Elsevier. - 0376-8716 .- 1879-0046. ; 256
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Journal article (peer-reviewed)abstract
- Background: Alcohol use disorders are prevalent mental disorders with significant health implications. Epigenetic alterations may play a role in their pathogenesis, as DNA methylation at several genes has been associated with these disorders. We have previously shown that methylation in the DLGAP2 gene, coding for a synaptic density protein, is associated with alcohol dependence. In this study, we aimed to examine the association between DLGAP2 methylation and treatment response among patients undergoing acamprosate treatment. Methods: 102 patients under acamprosate treatment were included. DNA methylation analysis at DLGAP2 was performed by bisulfite pyrosequencing at the start and after 3 -month treatment. Treatment outcomes were having a relapse during the treatment and severity of craving at the end of three months. Cox proportional hazard and linear regression models were performed. Results: Patients whose methylation levels were decreased during the treatment showed an increased risk for relapse within three months in comparison to the ones without methylation change (hazard ratio [HR]=2.44; 95% confidence interval [CI]=1.04, 5.73; p=0.04). For the same group, a positive association for the severity of craving was observed, yet statistical significance was not reached (beta=2.97; 95% CI= -0.41, 6.34; p=0.08). Conclusion: We demonstrate that patients whose DLGAP2 methylation levels decrease during acamprosate treatment are more likely to relapse compared to the ones without changes. This is in line with our previous findings showing that DLGAP2 methylation is lower in alcohol dependent subjects compared to controls, and might suggest a role for changes in DLGAP2 methylation in treatment response.
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| 8. |
- Özeren, Hüsamettin Deniz, et al.
(author)
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Prediction of Plasticization in a Real Biopolymer System (Starch) using Molecular Dynamics Simulations
- 2020
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In: Materials & design. - : Elsevier. - 0264-1275 .- 1873-4197. ; 187:108387
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Journal article (peer-reviewed)abstract
- Virgin biopolymers are often brittle, which means that they need efficient, sustainable, non-toxic plasticizers for most practical applications. Although the mechanical properties of biopolymers plasticized with e.g. sugars have been extensively investigated, the explanation why efficient plasticization normally only occurs above 20 wt% plasticizer is still lacking. In this work, starch/glycerol was used as a model system to show that all-atom molecular dynamics (MD) simulations can be used to capture the transition region at 20–30 wt% plasticizer, where plasticization becomes pronounced. Tensile properties and PVT data (densities and glass transition temperatures) were obtained both from MD simulations and from measurements on real starch/glycerol materials, confirming that MD could capture the experimentally observed transition region. Also, the simulated glycerol diffusivity correlated well with the trends in the mechanical properties. Percolation theory was used to derive a probable explanation of the observed transition. The results indicate that the MD methodology can be used also for other polymer/plasticizer systems and has the potential to be a valuable tool for optimizing the type and amount of plasticizer in a given polymer, as well as being a tool for the design of new efficient plasticizers.
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| 9. |
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| 10. |
- Öztayşi, Başar, et al.
(author)
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Fuzzy Analytic Hierarchy Process with Interval Type-2 Fuzzy Sets
- 2014
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In: Knowledge-Based Systems. - : Elsevier BV. - 0950-7051. ; 59, s. 48-57
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Journal article (peer-reviewed)abstract
- The membership functions of type-1 fuzzy sets have no uncertainty associated with it. While excessive arithmetic operations are needed with type-2 fuzzy sets with respect to type-1’s, type-2 fuzzy sets generalize type-1 fuzzy sets and systems so that more uncertainty for defining membership functions can be handled. A type-2 fuzzy set lets us incorporate the uncertainty of membership functions into the fuzzy set theory. Some fuzzy multicriteria methods have recently been extended by using type-2 fuzzy sets. Analytic Hierarchy Process (AHP) is a widely used multicriteria method that can take into account various and conflicting criteria at the same time. Our objective is to develop an interval type-2 fuzzy AHP method together with a new ranking method for type-2 fuzzy sets. We apply the proposed method to a supplier selection problem.
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