Investigation of AlGaN buffer layers on sapphire grown by MOVPE

In this work, AlGaN layers were grown on sapphire by metal-organic vapor phase epitaxy (MOVPE) on (0001)-oriented sapphire substrates, with the intention to investigate the effect of varying Al/MO and V/III ratios on the Al incorporation into the AlGaN layers. The parameters Al/MO and V/III describe the proportions of source material inside the reactor. With the help of optical transmission measurements, characteristic cut-off wavelengths of the Al xGa(1-x)N layers were determined. These wavelengths were used to calculate the Al content x of the layers, leading to values between 26.6% and 52.1%. Using the two process parameters Al/MO and V/III as input and the Al content of the AlGaN layers as a response variable, the experimental results were further investigated with the help of the software STATGRAPHICS. An estimated response surface for the variable x was generated. It was found that the Al incorporation is only tunable within a wide range for high V/III ratios of about 900. For constant Al/MO ratios and varying V/III ratios, two different growth characteristics were observed at high and low Al/MO values. This behavior is ascribed to the superposition of two oppositional effects

Türkiye’deki üniversite kütüphanelerinde RDA algısı, süreçler, sorunlar ve Özyeğin Üniversitesi Kütüphanesi örneği

Kütüphane hizmetlerinin her alanında olduğu gibi, yaşanan gelişme ve değişim kütüphane kataloglarındaki değişimi de gerekli kılmış ;kullanıcıya verimli, hızlı bibliyografik bilgi sunma, bilginin kayıtlı olduğu her türlü ortamdaki bilgi kaynağını daha detaylı, anlaşılır ve etkin biçimde tanımlama, ilişkisel veriler sunarak erişilebilirliğini arttırma gibi amaçlar ile daha güçlü ve işlevsel kütüphane kataloglarına ihtiyaç duyulmaya başlanmıştır. Bu doğrultuda Anglo Amerikan Kataloglama Kuralları 2 (AAKK2)’nin yerini alan yeni kataloglama standardı Resource Description and Access (RDA) dünyada ve ülkemizde kimi kütüphanelerde uygulanmaya başlanmıştır. Bu konudaki yeni yaklaşımlar, kurallar, uygulamalar gerek ülkemizde gerekse dünyada halen tartışılmakta; kataloglama ve meta data kütüphanecileri deneyimlerini paylaşmaktadır. Bu çalışmada RDA’nın kısaca yapısı, felsefesi ve terminolojisi literatüre dayalı olarak açıklanacak, Türkiye’deki üniversite kütüphanelerinde çalışan kataloglama kütüphanecilerinin RDA uygulamalarına ilişkin yapılmış bir anketin sonuçlarına dayanarak süreçler, yaşanan sorunlar ve RDA algısı ortaya konulacaktır. Çalışmada, Özyeğin Üniversitesi Kütüphanesi’ndeki RDA uygulamasından bahsedilerek beraberinde kütüphane kataloğunda AAKK’2 ye göre görülen değişim de örneklerle anlatılacaktır

Совершенствование технологии сооружения подводных переходов трубопроводов проложенных методом горизонтально-направленного бурения

Цель работы – разработка рекомендаций по применению технологии прокладки трубопроводов методом горизонтально-направленного бурения с применением защитного устройства. В процессе исследования проводились сравнительная характеристика существующих методов бестраншейной прокладки трубопроводов, расчет основных характеристик подводного перехода, подбор защитного устройства, исследование напряженно-деформированного состояния трубопровода с помощью конечно-элементного моделирования в программном комплексе Ansys. В результате исследования подобраны оптимальные параметры подводного перехода, методом конечно-элементного моделирования в программном комплексе Ansys определено напряженно-деформированнон состояние трубопровода с защитным устройством и без него.The purpose of the work is to develop recommendations for the application of pipeline laying technology by the method of horizontal directional drilling using a protective device. In the process of the research, the existing methods of trenchless pipeline laying, the calculation of the main characteristics of the underwater crossing, the selection of the protective device, the study of the stress-strain state of the pipeline using finite element modeling in the software complex Ansys were compared. As a result of the research, optimal parameters of the underwater transition were selected, the finite element method in the software complex Ansys determined the stress-strain state of the pipeline with the protective device and without it

Transcendental ethics

Due to copyright restrictions, the access to the full text of this article is only available via subscription.Our ontological, epistemological and metaphysical point of view is a very important determinant of how we conceive ethics and the possibility of ethical discourse. Kant, G.E. Moore and Wittgenstein had a quite eloquent discourse on ethics though they were, prima facie, incompatible. Kant regards ethics as belonging to supersensible reality, Moore, tells us that “goodness” is a non-natural and intuitively known notion. Wittgenstein says he “respected deeply” that that he himself could not talk about. Both Kant and Wittgenstein might at least find a common point on the idea of ethics being transcendental, whereas Moore strongly objects. I will try to show that Moore’s notion of “good” as a non-natural object that does not exist in time is difficult to conceive without assuming a “transcendental object” and the existence of a supersensible reality, as Kant does. I will investigate the role of transcending the limits of language in Wittgenstein’s conception of ethics where it manifests itself in our attitude towards the world. I will argue that Wittgenstein suggests a transcendental ethics with an account of viewing the world sub specie aeterni, without a need for a supersensible reality