125 results on '"Deniz, Umut"'
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2. Türkiye’de Muhasebe Eğitiminin Dünü Bugünü ve Geleceği
- Author
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Deniz Umut Doğan and Nalan Akdogan
- Subjects
accounting education ,accounting and technology ,future of accounting education ,muhasebe eğitimi ,muhasebe ve teknoloji ,muhasebe eğitiminin geleceği ,Finance ,HG1-9999 ,Business ,HF5001-6182 - Abstract
Bu çalışmada muhasebe eğitimi geçmişte nasıldı, yaşanan gelişmeler karşısında nasıl değişti bunlar belirlenmeye ve geleceğin muhasebe eğitimi nasıl olmalı bu soruya cevap aranmaya çalışılmıştır. Dünyada tüm kuruluşlar ve bireylerin içinde yer aldıkları finansal sistem içerisinde iletişim muhasebe sürecinin çıktıları olarak nitelendirebileceğimiz finansal ve finansal olmayan raporlar aracılığı ile sağlanır. Muhasebe eğitiminden beklenti de; - Bu raporların hazırlanması (Finansal Raporlama) - Doğru kararlar alınmasının desteklemesi amacıyla bu raporların analiz edilmesi (Finansal Analiz), - Bu raporlara duyulan güven seviyesinin arttırılması amacıyla raporların denetlenmesi, (Denetim) - İşletmelerde üretilen ürün ve hizmetlerin maliyetlerinin belirlenmesi (Maliyet Muhasebesi), - İşletmelerin finansal açıdan doğru kararlar alabilmeleri için maliyet bilgilerinin yönetimin finansal kararlarında kullanılabilmesi (Yönetim Muhasebesi), - İşletmelerin finansal ve finansal olmayan hedeflerine ulaşabilmesi amacıyla risklerin belirlenmesi ve tehditlere karşı önlemler alınması (İç Kontrol), - İşletmeye duyulan güven seviyesinin korunması ve geliştirilmesi, işletmelerin gelişmelere uyum kapasitelerinin arttırılması (İç Denetim) yukarıda belirtilen gereksinimleri karşılayabilmesidir. Günümüzü teknoloji çağı olarak nitelendirmemiz nedeniyle teknolojik gelişmelerin bu süreçlere entegre edilebilmesi, karar destek sistemlerinden faydalanılması muhasebe eğitiminin yaşanan teknolojik gelişmelere paralel ilerlemesi açısından ve eğitimde sürekliliğin sağlanmasında büyük önem taşımaktadır.
- Published
- 2022
- Full Text
- View/download PDF
3. A 0.7cm2 3.5GHz, -31 dBm Sensitivity Batteryless 5G Energy Harvester Backscattering Chip for Asset Identification in IoT-Enabled Warehouses
- Author
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Yildirim, Deniz Umut, primary, Jung, Jaeyoung, additional, Elsakka, Amr, additional, Moschetti, Giuseppe, additional, Lopez, Miguel M., additional, Hansryd, Jonás, additional, Palacios, Tomas, additional, and Chandrakasan, Anantha P., additional
- Published
- 2024
- Full Text
- View/download PDF
4. Termosifon ısı borusu performansının iş akışkanına hibrit nano parçacık katkısıyla değişiminin incelenmesi.
- Author
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Çelik, Erman, Özgen, Filiz, and Deniz, Umut
- Subjects
HEAT pipes ,THERMOSYPHONS ,NANOPARTICLES ,THERMAL conductivity ,NANOFLUIDS - Abstract
Copyright of Nigde Omer Halisdemir University Journal of Engineering Sciences / Niğde Ömer Halisdemir Üniversitesi Mühendislik Bilimleri Dergisi is the property of Nigde Omer Halisdemir Universitesi (NOHU), Muhendislik Fakultesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
5. All Ceramic-Based Metal-Free Ultra-broadband Perfect Absorber
- Author
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Soydan, Mahmut Can, Ghobadi, Amir, Yildirim, Deniz Umut, Erturk, Vakur Behcet, and Ozbay, Ekmel
- Published
- 2019
- Full Text
- View/download PDF
6. İŞLETMELERDE DEĞER DEĞİŞİMİNİN RAPORLANMASI: ENTEGRE RAPORLAMA VE ÜNİVERSİTELER İÇİN BİR MODEL ÖNERİSİ.
- Author
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ÇARDAK, Belgin Rana and DOĞAN, Deniz Umut
- Subjects
- *
VALUATION , *SOCIAL enterprises , *UNIVERSITIES & colleges , *INTELLECTUAL capital - Abstract
Integrated reports place the evolving value of an enterprise at its core and encompass both financial and non-financial data. It captures the shifts between the initial and final valuations over a period, shedding light on how an enterprise leverages its internal resources, including intellectual, human, social and relational, natural, and produced capital. Universities generate universal value and integrated reports provide a platform to articulate their narratives of value transformation. Analyzing the integrated reports of Edinburgh University in England, North West University in South Africa, and Yıldız Technical University in Turkey, this study formulates a pioneering model for an exemplary report. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
7. Near-absolute polarization insensitivity in graphene based ultra-narrowband perfect visible light absorber
- Author
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Yildirim, Deniz Umut, Ghobadi, Amir, and Ozbay, Ekmel
- Published
- 2018
- Full Text
- View/download PDF
8. Publisher Correction: Near-absolute polarization insensitivity in graphene based ultra-narrowband perfect visible light absorber
- Author
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Yildirim, Deniz Umut, Ghobadi, Amir, and Ozbay, Ekmel
- Published
- 2018
- Full Text
- View/download PDF
9. Nanosensors Based on Localized Surface Plasmon Resonance
- Author
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Deniz Umut Yildirim, Ekmel Ozbay, and Amir Ghobadi
- Subjects
Materials science ,Nanosensor ,Nanotechnology ,Surface plasmon resonance ,Plasmon - Published
- 2021
10. Past Present And Future Of Accounting Education In Turkey
- Author
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Nalan AKDOGAN and Deniz UMUT DOĞAN
- Abstract
Bu çalışmada muhasebe eğitimi geçmişte nasıldı, yaşanan gelişmeler karşısında nasıl değişti bunlar belirlenmeye ve geleceğin muhasebe eğitimi nasıl olmalı bu soruya cevap aranmaya çalışılmıştır. Dünyada tüm kuruluşlar ve bireylerin içinde yer aldıkları finansal sistem içerisinde iletişim muhasebe sürecinin çıktıları olarak nitelendirebileceğimiz finansal ve finansal olmayan raporlar aracılığı ile sağlanır. Muhasebe eğitiminden beklenti de; - Bu raporların hazırlanması (Finansal Raporlama) - Doğru kararlar alınmasının desteklemesi amacıyla bu raporların analiz edilmesi (Finansal Analiz), - Bu raporlara duyulan güven seviyesinin arttırılması amacıyla raporların denetlenmesi, (Denetim) - İşletmelerde üretilen ürün ve hizmetlerin maliyetlerinin belirlenmesi (Maliyet Muhasebesi), - İşletmelerin finansal açıdan doğru kararlar alabilmeleri için maliyet bilgilerinin yönetimin finansal kararlarında kullanılabilmesi (Yönetim Muhasebesi), - İşletmelerin finansal ve finansal olmayan hedeflerine ulaşabilmesi amacıyla risklerin belirlenmesi ve tehditlere karşı önlemler alınması (İç Kontrol), - İşletmeye duyulan güven seviyesinin korunması ve geliştirilmesi, işletmelerin gelişmelere uyum kapasitelerinin arttırılması (İç Denetim) yukarıda belirtilen gereksinimleri karşılayabilmesidir. Günümüzü teknoloji çağı olarak nitelendirmemiz nedeniyle teknolojik gelişmelerin bu süreçlere entegre edilebilmesi, karar destek sistemlerinden faydalanılması muhasebe eğitiminin yaşanan teknolojik gelişmelere paralel ilerlemesi açısından ve eğitimde sürekliliğin sağlanmasında büyük önem taşımaktadır.
- Published
- 2022
11. KURUMSAL RAPORLAMANIN GELİŞİMİ: ENTEGRE RAPORLAMA
- Author
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Deniz Umut Doğan and Burçak Kiziltan
- Subjects
General Medicine - Abstract
Finansal raporlar kullanılarak sunulan finansal bilgilerin yetersiz kalmasıyla, mevcut ve potansiyel yatırımcıların istek ve talepleri doğrultusunda finansal tablolarda önemli değişiklikler olmuş, fakat bu değişimler yatırımcıların beklentilerini tam anlamıyla karşılamamıştır. Yatırımcılar finansal bilgiler ile beraber işletmelerin hangi faaliyetleri gerçekleştirerek bu performansı gösterdiklerine ilişkin bilgilere, çevresel, sosyal ve yönetimsel açılardan da işletmelerin kararları, onları uygulama biçimleri ve stratejileri hakkında bilgi sahibi olmayı istemektedirler. Kurumsal yönetim anlayışının yaygınlaşmasıyla, işletmelerin finansal performansının yanında, finansal olmayan performansının da önem kazandığı ve yatırım kararları üzerinde etkili olduğu bir döneme geçilmeye başlanmıştır. İşletmelerin performansının tam ve eksiksiz değerlendirilebilmesi için finansal raporlara ilave olarak finansal olmayan raporlara da gereksinim duyulmaktadır. Bu çalışmada kurumsal raporlama, sürdürülebilirlik ve sürdürülebilir kalkınma terimlerine açıklık getirilip kurumsal sürdürülebilirlik, sürdürülebilirlik raporları ve Küresel Raporlama Girişimi (GRI) vurgulanarak, finansal ve finansal olmayan bilginin yer aldığı yeni bir raporlama türü olan entegre raporlamanın tanımı yapılmış ve kısaca dünya ve Türkiye’deki tarihsel gelişimine yer verilmiştir.
- Published
- 2021
12. SÜRDÜRÜLEBİLİR KALKINMA HEDEFLERİNDEN 5 NO'LU TOPLUMSAL CİNSİYET EŞİTLİĞİ HEDEFİNE ULAŞMADA TÜRKİYE'DE SÜRDÜRÜLEBİLİRLİK RAPORU DÜZENLEYEN İŞLETMELERİN 2020 VE 2021 YILI BEYANLARININ İNCELENMESİ VE SONUÇLARIN DEĞERLENDİRİLMESİ
- Author
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AKDOĞAN, Nalan and DOĞAN, Deniz Umut
- Subjects
- *
GENDER inequality , *SUSTAINABLE development - Abstract
Corporate Sustainability refers to the adaptation of environmental and social factors to activities and decision-making processes together with corporate governance principles, and the management of risks that may arise in these matters, in order to create long-term value for businesses. Sustainable Development, in its most widespread use, is defined as meeting the needs of present generations without compromising the ability of future generations to meet their own needs (Definition made in the 1987 UN Commission). Sustainable development contributes to the development of corporate sustainability by showing which areas businesses should focus on to achieve sustainable development and by enabling businesses, government and civil society to establish a common goal of achieving environmental, social and economic sustainability. For the Sustainable Development Goals, it is necessary to voluntarily report at the country level, to increase cooperation and partnerships at the regional level, and to monitor the progress at the global level. While gender equality and empowerment of women and girls is a goal in itself (Goal 5) in the SDGs, it is directly addressed in the sub-goals of 10 of the other 16 goals. In this study, the "Gender Equality" statements of 65 businesses in the BIST Sustainability Index for 2020 and 2021 were taken into account in order to evaluate the practices of businesses in the sustainability index towards gender equality. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
13. Structuring Strategic Management with Ratio Analysis Method: A Case Study in the Transition to SME TFRS Process
- Author
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Halıcı, Ali and Erhan, Deniz Umut
- Published
- 2013
- Full Text
- View/download PDF
14. The Structure of Strategic Networks in Professionalization Process of Occupations
- Author
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Kirkbesoglu, Erdem and Erhan, Deniz Umut
- Published
- 2012
- Full Text
- View/download PDF
15. All Ceramic-Based Metal-Free Ultra-broadband Perfect Absorber
- Author
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Mahmut Can Soydan, Vakur B. Erturk, Deniz Umut Yildirim, Amir Ghobadi, Ekmel Ozbay, Soydan, Mahmut Can, Ghobadi, Amir, Yıldırım, Deniz Umut, Ertürk, Vakur Behçet, and Özbay, Ekmel
- Subjects
Permittivity ,Materials science ,Transition metal carbides ,Transition metal nitrides ,Biophysics ,02 engineering and technology ,Nitride ,01 natural sciences ,Biochemistry ,Carbide ,010309 optics ,Photovoltaics ,0103 physical sciences ,Metal-free ,Ceramic ,Absorption (electromagnetic radiation) ,Plasmon ,business.industry ,Metamaterial ,021001 nanoscience & nanotechnology ,Metamaterials ,Broadband perfect absorber ,visual_art ,visual_art.visual_art_medium ,Optoelectronics ,0210 nano-technology ,business ,Biotechnology - Abstract
In this paper, we scrutinize unprecedented potential of transition metal carbides (TMCs) and nitrides (TMNs) for realization of light perfect absorption in an ultra-broad frequency range encompassing all of the visible (Vis) and near infrared (NIR) regions. For this purpose, two different configurations which are planar and trapezoidal array are employed. To gain insight on the condition for light perfect absorption, a systematic modeling approach based on transfer matrix method (TMM) is firstly utilized. Our modeling findings prove that the permittivity data of these TMCs and TMNs are closely matched with the ideal data. Thus, they can have stronger and broader absorption behavior compared to metals. Besides, these ceramic materials are preferred to metals due to the fact that they have better thermal properties and higher durability against erosion and oxidation than metals. This could provide the opportunity for design of highly efficient light harvesting systems with long-term stability. Numerical simulations are conducted to optimize the device optical performance for each of the proposed carbides and nitrides. Our findings reveal that these ceramic coatings have the broadest absorption response compared to all lossy and plasmonic metals. In planar configuration, titanium carbide (TiC) has the largest absorption bandwidth (BW) where an absorption above 0.9 is retained over a broad wavelength range of 405–1495 nm. In trapezoid architecture, vanadium nitride (VN) shows the widest BW covering a range from 300 to 2500 nm. The results of this study can serve as a beacon for the design of future high-performance energy conversion devices including solar vapor generation and thermal photovoltaics where both optical and thermal requirements can be satisfied. TÜBİTAK
- Published
- 2019
16. TFRS 16 KİRALAMALAR STANDARDININ FİNANSAL TABLOLAR ÜZERİNE ETKİSİ VE PERAKENDECİLİK SEKTÖRÜ ÜZERİNE BİR ARAŞTIRMA
- Author
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Deniz Umut Erhan and Nihan Akdoğan
- Subjects
İşletme ,IFRS 16,IAS 17,Financial Statements,Retail Sector ,TFRS 16,TMS 17,Finansal Tablolar,Perakendecilik Sektörü ,Management - Abstract
IFRS 16 Leasing Standard, which was issued on January 2016, regulates the recognition, measurement and reporting principles of the entire leasing transactions without making any differentiation between the financial and operational leasing activities and accordingly introduces similar recognition principles both for financial and operational leases. The standard will be effective from January 1st, 2019. With the enforcement of IFRS 16, the previous standard IAS 17 that regulates the financial leasing activities will be ceased.In this study, the new regulations introduced by the new standard will be analyzed and the impacts of new standard will be explained financial ratios between previous and new standard. This standard will lead different financial results especially for the companies that use significant operational lease such as, aviation companies, retail entities, travel and leisure, distribution companies., Ocak 2016 da yayınlanan TFRS 16 Kiralamalar standardı, kiralama işlemlerinde finansal ve faaliyet kiralaması ayrımı yapmaksızın, tüm kiralama işlemlerinin tanımlama, ölçme ve raporlama ilkelerini düzenlemekte ve faaliyet kiralamalarını da finansal kiralama gibi değerlendirilmesi uygulamasını getirmektedir. Standardın uygulaması 1 Ocak 2019 tarihi itibariyle başlayacaktır. TFRS 16 Kiralamalar standardının uygulamaya başlanması ile birlikte TMS 17 Kiralama İşlemleri standardı ve ilgili yorumlar yürürlükten kalkacaktır.Bu çalışmada TFRS 16 standardının getirdiği düzenlemelerin finansal tablolar üzerindeki etkisi incelenerek, perakende sektöründeki işletmelerin likidite durumu ve bazı finansal oranlarına etkisi önceki uygulamayla karşılaştırılarak analiz edilecektir. Standardın, havayolu, perakendecilik, seyahat, dağıtım sektörleri gibi faaliyet kiralamasını yoğun olarak kullanan sektörler için büyük ölçüde değişiklik yaratacağı beklenmektedir.
- Published
- 2020
17. Past Present And Future Of Accounting Education In Turkey
- Author
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Akdoğan, Nalan, Doğan, Deniz Umut, and Başka Kurum
- Subjects
Muhasebe ve Teknoloji ,Future of Accounting Education ,Accounting Education ,Muhasebe Eğitiminin Geleceği ,Accounting and Technology ,Muhasebe Eğitimi - Abstract
Bu çalışmada muhasebe eğitimi geçmişte nasıldı, yaşanan gelişmeler karşısında nasıl değişti bunlar belirlenmeye ve geleceğin muhasebe eğitimi nasıl olmalı bu soruya cevap aranmaya çalışılmıştır. Dünyada tüm kuruluşlar ve bireylerin içinde yer aldıkları finansal sistem içerisinde iletişim muhasebe sürecinin çıktıları olarak nitelendirebileceğimiz finansal ve finansal olmayan raporlar aracılığı ile sağlanır. Muhasebe eğitiminden beklenti de; - - - - - - - Bu raporların hazırlanması (Finansal Raporlama) Doğru kararlar alınmasının desteklemesi amacıyla bu raporların analiz edilmesi (Finansal Analiz), Bu raporlara duyulan güven seviyesinin arttırılması amacıyla raporların denetlenmesi, (Denetim) İşletmelerde üretilen ürün ve hizmetlerin maliyetlerinin belirlenmesi (Maliyet Muhasebesi), İşletmelerin finansal açıdan doğru kararlar alabilmeleri için maliyet bilgilerinin yönetimin finansal kararlarında kullanılabilmesi (Yönetim Muhasebesi), İşletmelerin finansal ve finansal olmayan hedeflerine ulaşabilmesi amacıyla risklerin belirlenmesi ve tehditlere karşı önlemler alınması (İç Kontrol), İşletmeye duyulan güven seviyesinin korunması ve geliştirilmesi, işletmelerin gelişmelere uyum kapasitelerinin arttırılması (İç Denetim) yukarıda belirtilen gereksinimleri karşılayabilmesidir. Günümüzü teknoloji çağı olarak nitelendirmemiz nedeniyle teknolojik gelişmelerin bu süreçlere entegre edilebilmesi, karar destek sistemlerinden faydalanılması muhasebe eğitiminin yaşanan teknolojik gelişmelere paralel ilerlemesi açısından ve eğitimde sürekliliğin sağlanmasında büyük önem taşımaktadır., In this study, it has been tried to determine how the accounting education was in the past, how they have changed in the face of the developments, and to seek an answer to this question, how should the accounting education of the future be. In the financial system in which all organizations and individuals are involved in the world, communication is provided through financial and non-financial reports, which we can describe as the outputs of the accounting process. Expectation from accounting education; - - - - - - - Preparation of these reports (Financial Reporting) Analyzing these reports in order to support making the right decisions (Financial Analysis), Auditing the reports in order to increase the level of confidence to these reports, (Audit) Determining the costs of the products and services produced in the enterprises (Cost Accounting), To be able to use the cost information in the financial decisions of the management so that the enterprises can make the right financial decisions (Management Accounting), Identifying risks and taking measures against threats in order for businesses to achieve their financial and nonfinancial goals (Internal Control), Maintaining and improving the level of trust to the business, increasing the capacity of businesses to adapt to developments (Internal Audit) to meet the above-mentioned requirements. Since we describe today as the age of technology, integrating technological developments into these processes and making use of decision support systems are of great importance in terms of the parallel progress of accounting education with technological developments and ensuring continuity in education.
- Published
- 2022
18. Strong light emission from a defective hexagonal boron nitride monolayer coupled to near-touching random plasmonic nanounits
- Author
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Deniz Umut Yildirim, Mahmut Can Soydan, Neval A. Cinel, Zeinab Eftekhari, Ekmel Ozbay, Amir Ghobadi, Eftekhari, Zeinab, Ghobadi, Amir, Soydan, Mahmut Can, Yıldırım, Deniz Umut, Cinel, Neval Ayşegül, and Özbay, Ekmel
- Subjects
Materials science ,Photoluminescence ,business.industry ,Orders of magnitude (temperature) ,Physics::Optics ,02 engineering and technology ,Purcell effect ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,010309 optics ,Optics ,0103 physical sciences ,Monolayer ,Physics::Atomic and Molecular Clusters ,Optoelectronics ,Light emission ,Spontaneous emission ,0210 nano-technology ,business ,Luminescence ,Plasmon - Abstract
In this Letter, we demonstrate strong light emission from defective hexagonal boron nitride (hBN) defect centers upon their coupling with disorder near-touching plasmonic units. Based on numerical simulations and characterization results, the plasmonic design at thin layer thicknesses of 20 nm can provide above 2 orders of magnitude enhancement in photoluminescence (PL) spectra. Moreover, this plasmonic platform shortens the luminescence lifetime of the emitters. The proposed design can be easily extended to other plasmonic-emitter combinations where strong light-matter interaction can be achieved using large-scale compatible routes. (C) 2021 Optical Society of America
- Published
- 2021
19. Numerical analysis of a thermally tunable spectrally selective absorber enabled by an all-dielectric metamirror
- Author
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Deniz Umut Yildirim, Volkan Erturk, Ekmel Ozbay, Veysel Erçağlar, Amir Ghobadi, Erçağlar, Veysel, Ertürk, Volkan, Ghobadi, Amir, Yıldırım, Deniz Umut, and Özbay, Ekmel
- Subjects
Materials science ,Silicon ,Guided-mode resonance ,business.industry ,Physics::Optics ,chemistry.chemical_element ,Germanium ,02 engineering and technology ,Dielectric ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Selective surface ,010309 optics ,Wavelength ,Optics ,Semiconductor ,chemistry ,0103 physical sciences ,0210 nano-technology ,business ,Refractive index - Abstract
In this Letter, we numerically propose a temperature-tunable, ultra-narrowband one-way perfect near-infrared radiation absorber with high transmission in the longer wavelength neighboring spectral range. We obtained this functionality by using a guided-mode resonance-based grating-waveguide metamirror that is comprised of silicon, a spacer dielectric, an absorbing semiconductor, and germanium. Within the ultra-narrow bandwidth of the guided-mode resonance excited at 1.16 µm with a full width at half-maximum of 3.3 nm, we confirmed perfect absorption when light is incident from one of the two opposite directions. Excitation from the opposite direction resulted in perfect reflection. The thickness of the entire structure is limited to about one third the operating wavelength. Furthermore, due to the temperature tunability of silicon and germanium the thermo-optical sensitivity was found to be approximately 0.068 nm/K. In addition to this spectral tunability, our proposed device supports transparency windows with 80% transmission in the higher wavelength ranges. Our device is highly promising in the applications of thermo-tunable modulators and obtaining single frequency near-infrared signals from broadband sources.
- Published
- 2020
20. One-way and near-absolute polarization insensitive near-perfect absorption by using an all-dielectric metasurface
- Author
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Andriy E. Serebryannikov, Deniz Umut Yildirim, Amir Ghobadi, Mahmut Can Soydan, Ekmel Ozbay, Yıldırım, Deniz Umut, Ghobadi, Amir, Soydan, Mahmut Can, Serebryannikov, Andriy E., and Özbay, Ekmel
- Subjects
Materials science ,Guided-mode resonance ,business.industry ,Resonance ,Physics::Optics ,02 engineering and technology ,Dielectric ,Grating ,021001 nanoscience & nanotechnology ,Polarization (waves) ,01 natural sciences ,Ray ,Atomic and Molecular Physics, and Optics ,010309 optics ,Laser linewidth ,Wavelength ,Optics ,0103 physical sciences ,0210 nano-technology ,business - Abstract
In this Letter, we numerically propose the one-way perfect absorption of near-infrared radiation in a tunable spectral range with high transmission in the neighboring spectral ranges. This functionality is obtained by using a two-dimensional, guided-mode resonance-based grating-waveguide metasurface that acts as a frequency-selective reflector, a spacer dielectric, and an absorbing oxide layer. Within the bandwidth of the excited guided-mode resonance excited at 1.82 mu m (with a full-width at half-maximum of 19 nm), we confirmed perfect absorption when light was incident from one of the two opposite directions, whereas in the other direction, perfect reflection was observed. The forward-to-backward absorption ratio reached as high as 60, while the thickness of the entire structure was on the order of the operating wavelength. In addition to the spectral tunability of the excited resonances and their bandwidths, our proposed device supports transparency windows with 65% transmission in the adjacent frequency bands. Our 2D grating is also verified to enable near-absolute insensitivity to the polarization state of incident light. Geometrical parameter modification also gives our design great tunability, as we also designed a device with a 300 nm absorption/reflection linewidth. (C) 2020 Optical Society of America
- Published
- 2020
21. Lithography-Free Random Bismuth Nanostructures For Full Solar Spectrum Harvesting And Mid-Infrared Sensing
- Author
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Mahmut Can Soydan, Deniz Umut Yildirim, Alpan Bek, Ekmel Ozbay, Amir Ghobadi, Vakur B. Erturk, ElifSarıgül Duman, Soydan, Mahmut Can, Ghobadi, Amir, Yıldırım, Deniz Umut, Ertürk, Vakur Behçet, and Özbay, Ekmel
- Subjects
Nanostructure ,Materials science ,business.industry ,Solar spectra ,Mid infrared ,chemistry.chemical_element ,Ultrahigh sensitivity ,Atomic and Molecular Physics, and Optics ,Lithography‐free fabrication ,Electronic, Optical and Magnetic Materials ,Bismuth ,Broadband absorbers ,chemistry ,Narrowband absorbers ,Optoelectronics ,business ,Lithography - Abstract
A lithography‐free, double‐functional single bismuth (Bi) metal nanostructure is designed, fabricated, and characterized for ultrabroadband absorption in the visible (vis) and near‐infrared (NIR) ranges, and for a narrowband response with ultrahigh refractive index sensitivity in the mid‐infrared (MIR) range. To achieve a large‐scale fabrication of the design in a lithography‐free route, the oblique‐angle deposition approach is used to obtain densely packed and randomly spaced/oriented Bi nanostructures. It is shown that this fabrication technique can provide a bottom‐up approach to controlling the length and spacing of the design. The characterization findings reveal a broadband absorbance above 0.8 in vis and NIR, and a narrowband absorbance centered around 6.54 µm. Dense architecture and extraordinary permittivity of Bi provide strong field confinement in ultrasmall gaps between nanostructures, and this can be utilized for a sensing application. An ultrahigh sensitivity of 2151 nm refractive‐index unit (RIU–1) is acquired, which is, as far as it is known, the experimentally highest sensitivity attained so far. The simple and large‐scale compatible fabrication route of the design together with the extraordinary optical response of Bi coating makes this design promising for many optoelectronic and sensing applications. Scientific and Technological Research Council of Turkey DPT‐HAMIT. Grant Numbers: 113E331, 114E374, 115F560 Turkish Academy of Sciences Türkiye Bilimsel ve Teknolojik Araştirma Kurumu. Grant Number: 115F560
- Published
- 2020
22. Raporlama Sisteminde Yükselen Trend Entegre Raporlama: Çimento ve Bankacılık Sektöründe Bir Araştırma
- Author
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Burçak Kızıltan and Deniz Umut Doğan
- Subjects
Yapısal Eşitlik Modellemesi ,HF5001-6182 ,Oran Analizi ,Business ,Entegre Raporlama - Abstract
Amaç – Çalışmada, sosyal, çevresel ve ekonomik bilgilerin tümünü tek bir raporda toparlayan entegre raporun, işletmelere finansal açıdan değer katıp katmayacağına cevap aranmış ve tespit edilecek etkilerin işletmelerin hem kendi performanslarında hem de sektörel bazda irdelenmesi amaçlanmıştır. Yöntem – Araştırmanın evrenini BİST endeksinde yer alan 475 işletme oluşturmuştur. Bu işletmelerden son üç yıl üst üste entegre rapor yayımlayan ikisi çimento ikisi bankacılık sektörü olmak üzere dört işletme araştırmanın örneklemini oluşturmaktadır. Bu sektörlerin öncülüğünde işletmelerin ülke menşeilerine göre farklarını araştırmak için yurtdışından yine aynı sektörlerde faaliyet gösteren ve son üç yıldır entegre rapor hazırlayan ikişer işletme seçilerek işletmelerin son üç yıllık entegre raporlarından alınan finansal tabloları ile entegre rapor uygulamasına başlamadan önceki üç yıllık finansal tablolarına oran analizi yöntemi uygulanmış ve gerçekleşen oranlar arasındaki farklar araştırılmıştır. Aynı zamanda, yapısal eşitlik modellemesi kullanılarak, entegre raporlama ve önceki döneme ait finansal raporların kârlılık üzerindeki etkileri araştırılmıştır. Bulgular – Çimento sektörünün analiz sonuçlarına göre; Türk işletmeleri her iki raporlama döneminde yabancı işletmelerden daha başarılı sonuçlara sahipken işletmeler menşeileri fark etmeksizin entegre rapor yayımlamadığı dönemlerde daha başarılı finansal sonuçlar elde etmişlerdir. Bankacılık sektöründe ise Türk bankaları finansal yapı oranlarında başarılı iken yabancı menşe ili bankalar kârlılık oranları analizlerinin sonuçlarında daha başarılı olmuştur. Bütün işletmelerde entegre rapor yayımladıkları dönemde hisse başı kârlarının arttığı sonucuna varılmış ve bankacılık sektöründe entegre rapor dönemlerinde finansman oranının sermaye yeterlilik oranı üzerinde anlamlı etkisinin olduğu belirlenmiştir. Tartışma – Araştırma sonucuna göre, entegre raporun işletmelerin finansal verileri üzerinde anlamlı bir etkisinin olmadığı finansal göstergelerin makroekonomik değişkenler, zaman, sosyal ve çevresel etkiler ile birlikte değerlendirilmesi gerekliliğini ortaya koymuştur.
- Published
- 2021
23. Girişimcilik Finansmanında Yeni Bir Model: Kitle Fonlaması
- Author
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Aslı Vural and Deniz Umut Doğan
- Subjects
Finansman Yöntemleri ,HF5001-6182 ,Business ,Girişimcilik Finansmanı ,Girişimcilik - Abstract
Amaç – Girişimcilerin en önemli problemi finansal kaynaklara ulaşmalarında yaşadıkları zorluklardır. Günümüzde Kitle Fonlaması modeli girişimcilerin gereksinim duydukları sermayeye ulaşmak için kullandıkları yeni finansal yöntemlerden birisidir. Türkiye’de Kitle Fonlaması modelinin kullanımı 2010 yılında başlamıştır. Ancak yasal engeller nedeniyle, 5 Aralık 2017 tarihindeki kanun değişikliğine kadar sadece Ödül ve Bağış Temelli Kitle Fonlaması modeli uygulanmıştır. Yapılan kanun değişikliğinin Hisse Temelli Kitle Fonlaması modelini yasal mevzuata aldığı ancak Borçlanma Temelli Kitle Fonlaması modelini içermediği görülmüştür. Dünya genelinde en çok uygulanan ve en yüksek fon sağlanan bu modelin uygulanmasının Kitle Fonlaması modelinin kullanımını artıracağı düşünülmektedir. Türkiye’de Borçlanma Temelli Kitle Fonlaması modelinin uygulanmasının sağlanması için yeni bir model önerilmesidir. Yöntem – Borçlanma Temelli Kitle Fonlaması ile ilgili dünya uygulamaları incelenerek, ülkemize özgü bir model oluşturulmuştur. Bulgular – Dünya uygulamalarının incelenmesi neticesinde Borçlanma Temelli Kitle Fonlamasının en çok kullanılan kitle fonlaması türü olduğu sonucuna varılmıştır. Tartışma –Türkiye uygulaması için “Bütünleştirici Borçlanma Temelli Kitle Fonlaması” olarak adlandırılan model önerilerek tartışmaya açılmıştır. Önerilen modelin Türkiye’deki Kitle Fonlaması uygulamalarında kullanılmasıyla gerçekleştirilecek proje sayıları ile toplanan fon miktarını artıracağı ve yatırımcılar için de tercih edilecek bir yatırım yöntemi olacağı düşünülmektedir.
- Published
- 2021
24. Nanosensors Based on Localized Surface Plasmon Resonance
- Author
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Yildirim, Deniz Umut, primary, Ghobadi, Amir, additional, and Ozbay, Ekmel, additional
- Published
- 2021
- Full Text
- View/download PDF
25. ANALİTİK PROSEDÜRLER STANDARDI (BDS 520) KAPSAMINDA İŞ ZEKÂSI MODELLERİNİN TASARLANMASI VE DENETİM SÜRECİNDE KULLANILMASI
- Author
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Deniz Umut Erhan
- Subjects
İşletme ,BDS 520,Analitik Prosedürler,İş Zekâsı,Denetim ,Management - Abstract
Günümüzde, bilişim ve teknolojik alanda yaşanan gelişmeler iş hayatına da yansımıştır. İş hayatındaki bu yansıma çeşitli mesleklerde de farklı bakış açılarının yakalanmasını ve iş yapma biçimlerini etkilemiştir. Yaşanan bu gelişmeler denetim mesleğinde de farklı tartışmalara yol açmıştır. Bilişim teknolojilerindeki gelişim, yapay zekâ, otomasyon, internet ve sosyal medya ağları üzerinden büyük hacimli verilerin elde edilebilmesi, işletmelerde iş zekası oluşturulması, öğrenen sistemler geliştirilmesi muhasebe ve denetim mesleğini de etkilemektedir. Dijitalleşme ile denetim mesleğinde daha fazla bilgisayar programlarından yararlanılacaktır. İşletmelere özgü iş zekası geliştirilmesi denetim sürecinde analitik prosedürlerin uygulanması sürecini de etkileyecektir. Çalışmada, BDS 520 sayılı “Anatitik Prosedürler” standardı rehberliğinde iş zekası modellerinin denetim amaçlarına uygun biçimde kullanılması için bir metodoloji ve uygun testlerin neler olabileceği tartışılmıştır. Çalışmanın ilk bölümde analitik prosedürler ve iş zekâsı konuları ele alınmıştır. İkinci bölümde analitik prosedürlerin denetim amaçlı kullanılması için işletmelerde iş zekâsı geliştirilmesi ve bilişim testleri ve uygunsuzlukların belirlenmesine kullanılabilecek analitik prosedürler değerlendirilmiştir. Sonuç bölümünde, hatalı, kuşkulu ve hileli işlemler olarak belirlenen yanlışlıkların finansal raporlamalara yansıyan izlerinin neler olabileceği, izlerin nasıl takip edilebileceğini anlamında testler önerilmiştir.
- Published
- 2019
26. Girişimcilik Finansmanında Yeni Bir Model: Kitle Fonlaması1 (A New Model In Entrepreneurship Financing: Crowdfunding)
- Author
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Aslı VURAL and Deniz Umut DOĞAN
- Subjects
Entrepreneurship ,Business administration ,Economics ,girişimcilik ,girişimcilik finansmanı finansman yöntemleri kitle fonlaması bütünleştirici borçlanma temelli kitle fonlaması ,entrepreneurship ,lcsh:Business ,entrepreneurship financing financing methods crowdfunding integrated debt based crowdfunding ,lcsh:HF5001-6182 - Abstract
Amaç – Girişimcilerin en önemli problemi finansal kaynaklara ulaşmalarında yaşadıkları zorluklardır. Günümüzde Kitle Fonlaması modeli girişimcilerin gereksinim duydukları sermayeye ulaşmak için kullandıkları yeni finansal yöntemlerden birisidir. Türkiye’de Kitle Fonlaması modelinin kullanımı 2010 yılında başlamıştır. Ancak yasal engeller nedeniyle, 5 Aralık 2017 tarihindeki kanun değişikliğine kadar sadece Ödül ve Bağış Temelli Kitle Fonlaması modeli uygulanmıştır. Yapılan kanun değişikliğinin Hisse Temelli Kitle Fonlaması modelini yasal mevzuata aldığı ancak Borçlanma Temelli Kitle Fonlaması modelini içermediği görülmüştür. Dünya genelinde en çok uygulanan ve en yüksek fon sağlanan bu modelin uygulanmasının Kitle Fonlaması modelinin kullanımını artıracağı düşünülmektedir. Türkiye’de Borçlanma Temelli Kitle Fonlaması modelinin uygulanmasının sağlanması için yeni bir model önerilmesidir. Yöntem – Borçlanma Temelli Kitle Fonlaması ile ilgili dünya uygulamaları incelenerek, ülkemize özgü bir model oluşturulmuştur. Bulgular – Dünya uygulamalarının incelenmesi neticesinde Borçlanma Temelli Kitle Fonlamasının en çok kullanılan kitle fonlaması türü olduğu sonucuna varılmıştır. Tartışma –Türkiye uygulaması için “Bütünleştirici Borçlanma Temelli Kitle Fonlaması” olarak adlandırılan model önerilerek tartışmaya açılmıştır. Önerilen modelin Türkiye’deki Kitle Fonlaması uygulamalarında kullanılmasıyla gerçekleştirilecek proje sayıları ile toplanan fon miktarını artıracağı ve yatırımcılar için de tercih edilecek bir yatırım yöntemi olacağı düşünülmektedir. Purpose – The most important problem faced by of entrepreneurs is the difficulty in accessing financial resources. Crowdfunding model is one of the new financial methods used by entrepreneurs to reach the capital they need. The use of crowdfunding model in Turkey began in 2010. However, due to legal barriers, only Reward and Donation Based Crowdfunding models were in use until the change of the law on 5 December 2017. The amendment of law includes the Equity Based Crowdfunding model in the legislation but it does not include the Debt Based Crowdfunding. In Turkey, it is considered that the Crowdfunding model will increase with the appliance of the Debt Based Crowdfunding which is the most applied and highest fund providing model. To propose a new model to ensure the implementation of the Debt Based Crowdfunding model in Turkey. Design/methodology/approach – A model of our country was created by examining the world's practices related to Debt Based Crowdfunding. Findings – As a result of the study of world applications, it was concluded that Debt Based Crowdfunding was the most widely used Crowdfunding type. Discussion –The model called "Integrated Debt Based Crowdfunding" for the Turkish application was proposed and opened for discussion. It is considered that using the proposed model in Crowdfunding applications in Turkey will lead to an increase in projects realized and funds collected, making it the preferred method of investment for investors. Keywords: Entrepreneurship, Entrepreneurship Financing, Financing Methods, Crowdfunding, Integrated Debt Based Crowdfunding.
- Published
- 2019
27. Raporlama Sisteminde Yükselen Trend Entegre Raporlama: Çimento ve Bankacılık Sektöründe Bir Araştırma (The IncreasingTrend in the Reporting System Integrated Reporting: A Research in the Cement and Banking Sectors)
- Author
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Kızıltan, Burçak, primary and Doğan, Deniz Umut, additional
- Published
- 2021
- Full Text
- View/download PDF
28. Unveiling the optical parameters of vanadium dioxide in the phase transition region: a hybrid modeling approach
- Author
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Koçer, Hasan, Çakır, Mehmet Cihan, Durna, Yılmaz, Yıldırım, Deniz Umut, Hajian, Hodjat, Ghobadi, Amir, Özbay, Ekmel, Sağlam, Necdet, Kurt, Hamza, Aydın, Koray, Koçer, Hasan, Çakır, Mehmet Cihan, Durna, Yılmaz, Yıldırım, Deniz Umut, Hajian, Hodjat, Ghobadi, Amir, Özbay, Ekmel, Sağlam, Necdet, Kurt, Hamza, and Aydın, Koray
- Abstract
The phase change behavior of vanadium dioxide (VO2) has been widely explored in a variety of optical and photonic applications. Commonly, its optical parameters have been studied in two extreme regimes: hot (metallic) and cold (insulating) states. However, in the transition temperatures, VO(2)acts like an inherent metamaterial with mixed metallic-insulating character. In this range, the portions of metallic and insulating inclusions are tuned by temperature, and therefore a gradual change of optical parameters can be achieved. In this paper, a universal hybrid modeling approach is developed to model VO(2)in the intermediate region. For this aim, the measured reflectivity data, is analyzed and matched through the transfer matrix method (TMM) simulations where an effective medium theory (EMT) is employed. Based on the findings of this approach, not only the relative portions of inclusions are tailored but also their grain shapes are significantly altered in the transition range. Finally, the modeling approach is testified by experimental findings through dynamic device applications operating at short and mid infrared wavelengths. In addition, the hysteretic behaviors on electrical, optical, and structural parameters of the VO(2)film along the heating and cooling cycles are demonstrated by the experiments and scrutinized by the simulations.
- Published
- 2021
29. Unveiling the optical parameters of vanadium dioxide in the phase transition region: a hybrid modeling approach
- Author
-
Çakır, Mehmet Cihan, Özbay, Ekmel, Sağlam, Necdet, Koçer, Hasan, Aydın, Koray, Hajian, Hodjat, Ghobadi, Amir, Yıldırım, Deniz Umut, Durna, Yılmaz, Kurt, Hamza, Çakır, Mehmet Cihan, Özbay, Ekmel, Sağlam, Necdet, Koçer, Hasan, Aydın, Koray, Hajian, Hodjat, Ghobadi, Amir, Yıldırım, Deniz Umut, Durna, Yılmaz, and Kurt, Hamza
- Abstract
The phase change behavior of vanadium dioxide (VO2) has been widely explored in a variety of optical and photonic applications. Commonly, its optical parameters have been studied in two extreme regimes: hot (metallic) and cold (insulating) states. However, in the transition temperatures, VO(2)acts like an inherent metamaterial with mixed metallic-insulating character. In this range, the portions of metallic and insulating inclusions are tuned by temperature, and therefore a gradual change of optical parameters can be achieved. In this paper, a universal hybrid modeling approach is developed to model VO(2)in the intermediate region. For this aim, the measured reflectivity data, is analyzed and matched through the transfer matrix method (TMM) simulations where an effective medium theory (EMT) is employed. Based on the findings of this approach, not only the relative portions of inclusions are tailored but also their grain shapes are significantly altered in the transition range. Finally, the modeling approach is testified by experimental findings through dynamic device applications operating at short and mid infrared wavelengths. In addition, the hysteretic behaviors on electrical, optical, and structural parameters of the VO(2)film along the heating and cooling cycles are demonstrated by the experiments and scrutinized by the simulations.
- Published
- 2021
30. Deep Subwavelength Light Confinement in Disordered Bismuth Nanorods as a Linearly Thermal‐Tunable Metamaterial
- Author
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Mahmut Can Soydan, Amir Ghobadi, Vakur B. Erturk, Ekmel Ozbay, Deniz Umut Yildirim, Soydan, Mahmut Can, Ghobadi, Amir, Deniz Umut, Deniz Umut, Ertürk, Vakur Behçet, and Özbay, Ekmel
- Subjects
Lithography-free ,Materials science ,Thermally-tunable ,business.industry ,Metamaterial ,Tunable metamaterials ,chemistry.chemical_element ,Condensed Matter Physics ,Bismuth ,chemistry ,Metamaterials ,Thermal ,Optoelectronics ,General Materials Science ,Nanorod ,business - Abstract
Materials with a tunable optical response that can be controllably tailored using external stimuli excitation have undergone considerable research effort for the development of active optical devices, such as thermo-optical modulators. Although bismuth (Bi) nanodots, embedded into glass matrices, have been proven to have a thermo-optical response, the recyclability of the structure in solid-liquid phase transitions is a major challenge. Herein, a facile and lithography-free fabrication method is proposed to realize densely packed stand-alone Bi nanorods (NRs), with deep subwavelength gaps and a resonance at the midinfrared range (lambda approximately equal to 4.462 mu m). Owing to these ultrasmall gaps that support lossy Mie-like resonances, strong field confinement is achieved, and the resonance wavelength exhibits great sensitivity to temperature, as the thermal sensitivity reaches as high as 1.0316 nm degrees C-1. This operation is conducted in the moderate temperature interval of 25-85 degrees C, which is far from the melting point of Bi. Overall, our simple, robust, and high-performance device is highly promising for realizing optical switches, thermo-optic modulators, and infrared camouflage.
- Published
- 2020
31. Disordered and densely packed ITO nanorods as an excellent lithography-free optical solar reflector metasurface for the radiative cooling of spacecraft
- Author
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Deniz Umut Yildirim, Okan Atesal, Mehmet Deniz Çalişkan, Amir Ghobadi, Ahmet Toprak, Mahmut Can Soydan, Ekmel Ozbay, Yıldırım, Deniz Umut, Ghobadi, Amir, Soydan, Mahmut Can, Ateşal, Okan, Toprak, Ahmet, Çalışkan, Mehmet Deniz, and Özbay, Ekmel
- Subjects
Transparent conductive oxides ,Materials science ,Spacecraft ,Radiative cooling ,business.industry ,Oblique-angle deposition ,Solar energy ,Space exploration ,Metasurfaces ,Optical solar re ectors ,Broadband ,Plasmonics ,Optoelectronics ,Nanorod ,Astrophysics::Earth and Planetary Astrophysics ,business ,Lithography ,Plasmon - Abstract
Date of Conference: 11-15 August 2019 Conference Name: SPIE Nanoscience + Engineering, 2019 Optical Solar Reflectors (OSRs) form the physical interface between the spacecraft and space and they are essential for the stabilization and uniform distribution of temperature throughout the spacecraft. OSRs need to possess a spectrally selective response of broadband and perfect electromagnetic wave absorption in the thermal-infrared spectral range, while strongly reflecting the solar energy input. In this work, we experimentally show that disordered and densely packed ITO nanorod forests can be used as an excellent top-layer metasurface in a metal-insulator-oxide cavity configuration, and a thermal-emissivity of 0.97 is experimentally realized in the spectral range from 2.5 to 25 μm. The low-loss dielectric response of ITO in the solar spectrum, from 300 nm to 2.5 μm range limited the solar absorptivity to an experimental value of 0.167. These make our proposed design highly promising for its application in space missions due to combining high throughput, robustness, low cost with ultra-high performance. The Society of Photo-Optical Instrumentation Engineers (SPIE)
- Published
- 2019
32. Disordered and densely packed ITO nanorods as an excellent lithography-free optical solar reflector metasurface
- Author
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Mahmut Can Soydan, Amir Ghobadi, Ekmel Ozbay, Deniz Umut Yildirim, Ahmet Toprak, Mehmet Deniz Çalişkan, Okan Atesal, Yıldırım, Deniz Umut, Ghobadi, Amir, Soydan, Mahmut Can, Ateşal, Okan, Toprak, Ahmet, Çalışkan, Mehmet Deniz, and Özbay, Ekmel
- Subjects
Fabrication ,Materials science ,Transparent conductive oxides ,Oblique-angle deposition ,Physics::Optics ,02 engineering and technology ,7. Clean energy ,01 natural sciences ,010309 optics ,Operating temperature ,0103 physical sciences ,Metamaterial perfect absorbers ,Electrical and Electronic Engineering ,Lithography ,Plasmon ,Spacecraft ,business.industry ,Metamaterial ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Indium tin oxide ,Metasurfaces ,13. Climate action ,Physics::Space Physics ,Optical solar reflectors ,Optoelectronics ,Plasmonics ,Nanorod ,0210 nano-technology ,business ,Biotechnology - Abstract
Precise control and stabilization of the operating temperature environment of spacecraft and satellites during their life cycle is of paramount importance to increase device reliabilities and reduce the thermomechanical constraints. Optical solar reflectors are the physical interface between the spacecraft and space, and they are broadband mirrors for the solar spectrum, while having strong thermal emission in the mid-infrared part of the electromagnetic spectrum. Strong light matter interactions in metamaterials and metasurfaces offer significant advantages compared to the conventional methods in performance, weight, launch, and assembly costs. However, the fabrication complexity of these metastructures due to necessitating lithography hinders their upscaling, reproducibility, large-area compatibility, and mass production. In this regard, we propose a facile, lithography-free fabrication route, exploiting oblique deposition to design a metasurface based on disordered and densely packed Indium Tin Oxide (ITO) nanorod forests. The excellent light trapping capability of the nanorod forests, randomness in the geometrical dimensions of these nanorods, combined with the lossy plasmonic nature of ITO in the thermal-infrared range led to strong coupling of thermal radiation to broad plasmonic resonances and, consequently, an experimental emissivity of 0.968, in a very wide range from 2.5 to 25 pm. In the solar spectrum, the low-loss dielectric characteristic of ITO resulted in an experimental solar absorptivity as small as 0.168. Our proposed design with high throughput, robustness, low cost, and high performance, therefore, shows great promise not only for space missions, but also for promoting environmentally friendly passive radiative cooling for our planet and thermal imaging in the field of security labeling.
- Published
- 2019
33. Colorimetric and near-absolute polarization-insensitive refractive-index sensing in all-dielectric guided-mode resonance based metasurface
- Author
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Murat Gokbayrak, Amir Ghobadi, Bayram Butun, Ahmet Toprak, Deniz Umut Yildirim, Ekmel Ozbay, Mahmut Can Soydan, Yıldırım, Deniz Umut, Ghobadi, Amir, Soydan, Mahmut Can, Gökbayrak, Murat, Toprak, Ahmet, Bütün, Bayram, and Özbay, Ekmel
- Subjects
Materials science ,Resonance structures ,Guided-mode resonance ,business.industry ,02 engineering and technology ,Dielectric ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Polarization (waves) ,01 natural sciences ,Quantum mechanics ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,General Energy ,Optics ,Polarization ,Molecule ,Physical and Theoretical Chemistry ,0210 nano-technology ,business ,Thickness ,Layers ,Refractive index - Abstract
Colorimetric detection of target molecules with insensitivity to incident-light polarization has attracted considerable attention in recent years. This resulted from the ability to provide rapid output and reduced assay times as a result of color changes upon altering the environment that are easily distinguishable by the naked eye. In this paper, we propose a highly sensitive refractive-index sensor, utilizing the excitation of guided modes of a novel two-dimensional periodically modulated dielectric grating-waveguide structure. The optimized nanosensor can numerically excite guided-mode resonances with an ultranarrow linewidth (full width at half-maximum) of 0.58 nm. Sensitivity is numerically investigated by considering the deposition of dielectric layers on the structure. For a layer thickness of 30 nm, the maximum sensitivity reached as high as 110 nm/refractive index unit (RIU), resulting in a very high figure of merit of 190. The fabricated devices with 30 nm aluminum oxide and zinc oxide coatings achieved a maximum sensitivity of 235.2 nm/RIU with a linewidth of 19 nm. Colorimetric detection with polarization insensitivity is confirmed practically by a simple optical microscope. Samples with different coatings have been observed to have clearly distinct colors, while the color of each sample is nearly identical upon azimuthal rotation. Excellent agreement is obtained between the numerical and experimental results regarding the spectral position of the resonances and sensitivity. The proposed device is, therefore, highly promising in efficient, highly sensitive, almost lossless, and compact molecular diagnostics in the field of biomedicine with personalized, label-free, early point-of-care diagnosis and field analysis, drug detection, and environmental monitoring.
- Published
- 2019
34. Strong light emission from a defective hexagonal boron nitride monolayer coupled to near-touching random plasmonic nanounits
- Author
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Eftekhari, Zeinab, primary, Ghobadi, Amir, additional, Soydan, Mahmut Can, additional, Yildirim, Deniz Umut, additional, Cinel, Neval, additional, and Ozbay, Ekmel, additional
- Published
- 2021
- Full Text
- View/download PDF
35. General Outlook on Financial Structure and Capital Adequacy of ISE-30 Companies during Economic Crisis (2008-2009)
- Author
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Erhan, Deniz Umut, primary and Akdogan, M. Ugur, additional
- Published
- 2013
- Full Text
- View/download PDF
36. Numerical analysis of a thermally tunable spectrally selective absorber enabled by an all-dielectric metamirror
- Author
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Erçaglar, Veysel, primary, Erturk, Volkan, additional, Ghobadi, Amir, additional, Yildirim, Deniz Umut, additional, and Ozbay, Ekmel, additional
- Published
- 2020
- Full Text
- View/download PDF
37. Deep Subwavelength Light Confinement in Disordered Bismuth Nanorods as a Linearly Thermal‐Tunable Metamaterial
- Author
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Soydan, Mahmut Can, primary, Ghobadi, Amir, additional, Yildirim, Deniz Umut, additional, Erturk, Vakur Behcet, additional, and Ozbay, Ekmel, additional
- Published
- 2020
- Full Text
- View/download PDF
38. One-way and near-absolute polarization insensitive near-perfect absorption by using an all-dielectric metasurface
- Author
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Yildirim, Deniz Umut, primary, Ghobadi, Amir, additional, Soydan, Mahmut Can, additional, Serebryannikov, Andriy E., additional, and Ozbay, Ekmel, additional
- Published
- 2020
- Full Text
- View/download PDF
39. Unveiling the optical parameters of vanadium dioxide in the phase transition region: a hybrid modeling approach
- Author
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Cakir, Mehmet Cihan, primary, Kocer, Hasan, additional, Durna, Yilmaz, additional, Yildirim, Deniz Umut, additional, Ghobadi, Amir, additional, Hajian, Hodjat, additional, Aydin, Koray, additional, Kurt, Hamza, additional, Saglam, Necdet, additional, and Ozbay, Ekmel, additional
- Published
- 2020
- Full Text
- View/download PDF
40. Lithography‐Free Random Bismuth Nanostructures for Full Solar Spectrum Harvesting and Mid‐Infrared Sensing
- Author
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Soydan, Mahmut Can, primary, Ghobadi, Amir, additional, Yildirim, Deniz Umut, additional, Duman, ElifSarıgül, additional, Bek, Alpan, additional, Erturk, Vakur Behcet, additional, and Ozbay, Ekmel, additional
- Published
- 2019
- Full Text
- View/download PDF
41. ENTEGRE RAPORLAMA İLKELERİ ÇERÇEVESİNDE TÜRKİYE ve DÜNYA ÖRNEKLERİYLE BİR İNCELEME.
- Author
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SUSMA, S. M. M. M. Göktuğ and DOĞAN, Deniz Umut
- Abstract
Copyright of Accounting & Auditing Perspective Magazine / Muhasebe ve Denetime Bakış is the property of Union of Chambers of Certified Public Accountants of Turkey (TURMOB) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2022
42. Publisher Correction: Near-absolute polarization insensitivity in graphene based ultra-narrowband perfect visible light absorber
- Author
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Deniz Umut Yildirim, Amir Ghobadi, and Ekmel Ozbay
- Subjects
Multidisciplinary ,Materials science ,business.industry ,Graphene ,lcsh:R ,lcsh:Medicine ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Polarization (waves) ,Publisher Correction ,01 natural sciences ,law.invention ,010309 optics ,Optics ,Narrowband ,law ,0103 physical sciences ,ComputingMethodologies_DOCUMENTANDTEXTPROCESSING ,lcsh:Q ,lcsh:Science ,0210 nano-technology ,business ,Visible spectrum - Abstract
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
- Published
- 2018
43. Near-absolute polarization insensitivity in grapheme based ultra-narrowband perfect visible light absorber
- Author
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Ekmel Ozbay, Deniz Umut Yildirim, Amir Ghobadi, and Özbay, Ekmel
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Materials science ,Terahertz radiation ,Nanophotonics ,lcsh:Medicine ,Physics::Optics ,02 engineering and technology ,Dielectric ,Grating ,01 natural sciences ,Article ,law.invention ,010309 optics ,Narrowband ,law ,0103 physical sciences ,lcsh:Science ,Absorption (electromagnetic radiation) ,Multidisciplinary ,business.industry ,Graphene ,lcsh:R ,021001 nanoscience & nanotechnology ,Optoelectronics ,lcsh:Q ,0210 nano-technology ,business ,Visible spectrum - Abstract
Strong light-graphene interaction is essential for the integration of graphene to nanophotonic and optoelectronic devices. The plasmonic response of graphene in terahertz and mid-infrared regions enhances this interaction, and other resonance mechanisms can be adopted in near-infrared and visible ranges to achieve perfect light absorption. However, obtaining near-absolute polarization insensitivity with ultra-narrow absorption bandwidth in the visible and near-infrared regimes remains a challenge. In this regard, we numerically propose a graphene perfect absorber, utilizing the excitation of guided-modes of a dielectric slab waveguide by a novel sub-wavelength dielectric grating structure. When the guided-mode resonance is critically coupled to the graphene, we obtain perfect absorption with an ultra-narrow bandwidth (full-width at half-maximum) of 0.8 nm. The proposed design not only preserves the spectral position of the resonance, but also maintains >98% absorption at all polarization angles. The spectral position of the resonance can be tuned as much as 400 nm in visible and near-infrared regimes by tailoring geometrical parameters. The proposed device has great potential in efficient, tunable, ultra-sensitive, compact and easy-to-fabricate advanced photodetectors and color filters.
- Published
- 2018
44. Disordered and densely packed ITO nanorods as an excellent lithography-free optical solar reflector metasurface for the radiative cooling of spacecraft
- Author
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Yildirim, Deniz Umut, primary, Ghobadi, Amir, additional, Soydan, Mahmut Can, additional, Atesal, Okan, additional, Toprak, Ahmet, additional, Caliskan, Mehmet Deniz, additional, and Ozbay, Ekmel, additional
- Published
- 2019
- Full Text
- View/download PDF
45. Colorimetric and Near-Absolute Polarization-Insensitive Refractive-Index Sensing in All-Dielectric Guided-Mode Resonance Based Metasurface
- Author
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Yildirim, Deniz Umut, primary, Ghobadi, Amir, additional, Soydan, Mahmut Can, additional, Gokbayrak, Murat, additional, Toprak, Ahmet, additional, Butun, Bayram, additional, and Ozbay, Ekmel, additional
- Published
- 2019
- Full Text
- View/download PDF
46. Disordered and Densely Packed ITO Nanorods as an Excellent Lithography-Free Optical Solar Reflector Metasurface
- Author
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Yildirim, Deniz Umut, primary, Ghobadi, Amir, additional, Soydan, Mahmut Can, additional, Atesal, Okan, additional, Toprak, Ahmet, additional, Caliskan, Mehmet Deniz, additional, and Ozbay, Ekmel, additional
- Published
- 2019
- Full Text
- View/download PDF
47. Girişimcilik Finansmanında Yeni Bir Model: Kitle Fonlaması1 (A New Model In Entrepreneurship Financing: Crowdfunding)
- Author
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VURAL, ASLI, primary and DOĞAN, DENİZ UMUT, additional
- Published
- 2019
- Full Text
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48. Structuring Strategic Management with Ratio Analysis Method: A Case Study in the Transition to SME TFRS Process
- Author
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Deniz Umut Erhan and Ali Halici
- Subjects
Knowledge management ,Balanced scorecard ,Stratejic Management ,business.industry ,Accounting management ,Stratejic Decision ,Financial Tables Analysis ,Accounting information system ,Economics ,General Materials Science ,Strategic management ,Ratio Analysis Method ,business ,SWOT analysis ,Competence (human resources) ,Quality function deployment ,Strategic financial management - Abstract
Techniques such as SWOT Analysis, Balanced Scorecard, and Quality Function Deployment (QFD), which are the most acknowledged and used strategic management methods in business management, were used in various studies individually or in combination. On the other hand, especially executive managers in small and medium-sized enterprises do not have the competence of using financial tables to support their strategic, operational and tactical decisions. The most important aim of the financial reporting by accounting system is to produce reliable, understandable and comparable information and fulfill the needs of the user. Realistic presentation, producing accurate and reliable information, providing transparency, giving the sufficient information that will meet the needs of the user and building a global accounting language in order to provide comparability of global applications are the main goals and objectives of the regulatory authorities in accounting. Global attention drawn by published international financing reporting standards and its ability to provide uniformity in different country applications, reveal the need for specific studies for small and medium-sized enterprises on this subject. The aim of this study is to evaluate the financial tables by ratio analysis in a small and medium-sized enterprise and determine the effects on strategic management decisions and to evaluate the contribution of these data on building corporate strategies.
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- 2013
- Full Text
- View/download PDF
49. TFRS 16 KİRALAMALAR STANDARDININ FİNANSAL TABLOLAR ÜZERİNE ETKİSİ VE PERAKENDECİLİK SEKTÖRÜ ÜZERİNE BİR ARAŞTIRMA.
- Author
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AKDOĞAN, Nihan and DOĞAN, Deniz Umut
- Subjects
- *
FINANCIAL ratios , *LEASES , *FINANCIAL statements , *LEISURE - Abstract
IFRS 16 Leasing Standard, which was issued on January 2016, regulates the recognition, measurement and reporting principles of the entire leasing transactions without making any differentiation between the financial and operational leasing activities and accordingly introduces similar recognition principles both for financial and operational leases. The standard will be effective from January 1st, 2019. With the enforcement of IFRS 16, the previous standard IAS 17 that regulates the financial leasing activities will be ceased. In this study, the new regulations introduced by the new standard will be analyzed and the impacts of new standard will be explained financial ratios between previous and new standard. This standard will lead different financial results especially for the companies that use significant operational lease such as, aviation companies, retail entities, travel and leisure, distribution companies. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
50. Lithography‐Free Random Bismuth Nanostructures for Full Solar Spectrum Harvesting and Mid‐Infrared Sensing.
- Author
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Soydan, Mahmut Can, Ghobadi, Amir, Yildirim, Deniz Umut, Duman, ElifSarıgül, Bek, Alpan, Erturk, Vakur Behcet, and Ozbay, Ekmel
- Subjects
SOLAR spectra ,BISMUTH ,NANOSTRUCTURES ,REFRACTIVE index ,HARVESTING ,PERMITTIVITY - Abstract
A lithography‐free, double‐functional single bismuth (Bi) metal nanostructure is designed, fabricated, and characterized for ultrabroadband absorption in the visible (vis) and near‐infrared (NIR) ranges, and for a narrowband response with ultrahigh refractive index sensitivity in the mid‐infrared (MIR) range. To achieve a large‐scale fabrication of the design in a lithography‐free route, the oblique‐angle deposition approach is used to obtain densely packed and randomly spaced/oriented Bi nanostructures. It is shown that this fabrication technique can provide a bottom‐up approach to controlling the length and spacing of the design. The characterization findings reveal a broadband absorbance above 0.8 in vis and NIR, and a narrowband absorbance centered around 6.54 µm. Dense architecture and extraordinary permittivity of Bi provide strong field confinement in ultrasmall gaps between nanostructures, and this can be utilized for a sensing application. An ultrahigh sensitivity of 2151 nm refractive‐index unit (RIU–1) is acquired, which is, as far as it is known, the experimentally highest sensitivity attained so far. The simple and large‐scale compatible fabrication route of the design together with the extraordinary optical response of Bi coating makes this design promising for many optoelectronic and sensing applications. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
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