Effect of Ag2O addition on the intergranular properties of the superconducting Bi–(Pb)–Sr–Ca–Cu–O system

The effect of Ag2O addition on the Bi–(Pb)–Sr–Ca–Cu–O system has been investigated in terms of ac susceptibility, phase evolution, critical current density and critical temperature. It was found that as the amount of Ag2O addition increases, the intergranular critical current density decreases in our samples (Bi1.84Pb0.34Sr1.91Ca2.03Cu3.06O10) fabricated by ammonium nitrate technique. The analysis for comparison is based on the suppression degree of the diamagnetic behaviour with respect to fields, rapid or slow shift of the summit in χ'(T) to lower temperature with increasing field amplitude and the sharpness of the transition of χ'(T) for intergranular component for the same field amplitude. We also qualitatively discuss experimental results in the framework of the critical state model. The room temperature XRD diagram indicates the presence of large amount of high-Tc (2223) phase. The percentage of Bi-2223 phase in the phase mixture was estimated from the intensities of high-Tc (2223) and low-Tc (2212) phase peaks as 78% for the pure BSCCO sample. Among the Ag2O-added BSCCO samples studied, the one in which 5 wt%Ag2O was added shows the highest rate of Bi-2223 formation as 92%. The SEM analysis reveals some morphological changes induced by silver addition

Osmanlı Arşivi’nde bulunan 365 no’lu Sadaret defterinin transkripsiyonu ve değerlendirilmesi

Bu çalışmada, Osmanlı Arşivi’nde Sadaret Defterleri Kataloğu’nda kayıtlı 365 numaralı teşrifat defteri incelenmiştir. Eski harfli Türkçe ile yazılmış ve 192 sayfadan oluşan defter Latin harflerine çevrilmiş ve her bir konu sadeleştirilerek özetlenmiştir. Defter Türk tarihinin kritik süreçlerinden 1835-1844 dönemini kapsamaktadır. Bu dönemde Osmanlı devlet teşkilatı önemli bir değişikliğe uğrayarak çağdaş kabine sistemine geçmiştir. Türk tarihinin en büyük reformcularından II. Mahmud ölmüş, Sultan Abdülmecid tahta çıkmıştır. Tanzimat Fermanı ilan edilmiştir. Osmanlı/Türk modernleşmesi, batılılaşma cereyanı veya inkılap tarihi dediğimiz süreçler genellikle Tanzimat’ın ilanıyla başlatılır. Osmanlı yönetimi bu süreçte gelişmiş Avrupa devletlerinin birtakım kurumlarını, eğitim sistemindeki bazı uygulamaları, hukuk normlarını ve daha pek çok sahadaki uygulamaları ithal etmeye başlamıştır. İncelenen defter, Türk tarihinin en çok tartışılan ve güncelliğini daima koruyan bu dönemlerine ışık tutmaktadır. Defter, Osmanlı merkez teşkilatındaki bürokratik düzenlemeler, yeni yapılanmaya bağlı olarak merkezde ve taşrada açılan resmî kurumlar, buralara yapılan atamalar, devlet törenleri ve alaylar, bunlarda uygulanan teşrifat sistemi, protokol düzeni ve giyilen kıyafetler, iç siyasi gelişmeler, aziller ve tayinler, idari kararlar, Bâbıâli-Saray ilişkileri, saray adetleri, evlilikler, surre alayları, inşa edilen yapılar ve daha pek çok konu hakkında bilgi içermektedir. Ayrıca Osmanlı arşivini modernleştirmeye dönük adımların, kütüphaneleri ve arşiv sistemini ıslaha yönelik alınan kararların belgeleri bulunmaktadır. Bu konularda çalışan araştırmacıların yanı sıra, tarih, edebiyat, sanat tarihi, kültür tarihi ve folklor araştırmacılarına veriler sunmaktadır.In this study, the protocol book that is the registry number 365 registered in the Grand Viziership Catalogue in the Ottoman Archives was examined. The book written with old Ottoman letters and has 192 pages, was translated to latin letters and summarized every subject. The book covers 1835-1944 years, critical period of Turkish history. In this period, the Ottoman state organization had a significant change and switched to the modern cabinet system. Mahmud the Second who are one of the greatest reformers in Turkish history has died then Sultan Abdülmecid took the throne of Ottoman Empire. Imperial edict of Gülhane was declared. Ottoman/Turkish modernization, westernization or revolution history started with declaration of imperial edict of Gülhane. In this period, the Ottoman administration started to import some institutions of developed European states, some practices in the education system, legal norms and practices in many fields. The book, examines these periods of Turkish history, which are the most discussed and always keep update. The book was examined, contains Bureaucratic arrangements in the Ottoman central organization, official institutions which opened in center and countryside depending on the new structuring, assignments to these places, state ceremionies, the protocol system applied in these, domestic political developments, appointments and dismissals, administrative decisions, Grand Viziership-Palace relations, palace customs, marriages, surre processions, built structures and more. In addition, the book contains steps to modernize the Ottoman archive and decisions taken to renew libraries and archive system. And also in addition to researchers working on these issues, the book provides data to researchers on field of history, literature, art history, cultural history and folklore

Morphological, microstructural and electrical examinations on ZnO film on p-Si wafer

Gokcen, Muharrem/0000-0001-9063-3028; Yildirim, Gurcan/0000-0002-5177-3703WOS: 000309679600008This study reports not only main electrical and dielectric characteristics of Ag/ZnO/p-Si heterostructure with the aid of the experimental admittance measurements at room temperature and theoretical approaches but also the microstructure and surface morphology of the heterostructure by means of X-ray diffraction, scanning electron microscopy and atomic force microscopy measurements. The results obtained show that the sample, obtaining Wurtzite structure with the (002) preferred orientation, has a fine crystalline microstructure consisting of micro-sized hexagonal rods growing uniformly in large scale on the film surface. When the diameters of the rods are found to vary from 0.5 mu m to 1.5 mu m, thickness values are observed to be about 2 mu m. Further, series resistance (R-s) and some other electronic parameters of the heterostructure are obtained by the capacitance-voltage (C-V), conductance-voltage (G-V) and C-2-V measurements. Moreover, voltage (V) and frequency (f) dependence of dielectric parameters such as dielectric constant (epsilon'), dielectric loss (epsilon aEuro(3)), dielectric loss tangent (tan delta), real and imaginary parts of electric modulus (IeaEuro(2) and IeaEuro(3)) are determined and discussed. It is found that both electrical and dielectric parameters of the heterostructure prepared in this work depend strongly on the applied bias voltage and frequency.Abant Izzet Baysal University Scientific Research Projects UnitAbant Izzet Baysal University [2011.03.02.434]This work is financially supported by the Abant Izzet Baysal University Scientific Research Projects Unit under contract number 2011.03.02.434

Investigation of Sm -> Ca substitution in Bi(Pb)SrCaCuO high temperature superconductor by low field AC magnetic susceptibility

Yegen, Dincer/0000-0003-3180-600X; Terzioglu, Cabir/0000-0002-3944-0367WOS: 000247402300064We have investigated the effect of Sm substitution in Bi(Pb)SrCaCuO system by performing AC susceptibility (chi = chi' + i chi ''), XRD (X Ray Diffraction) and SEM (Scanning Electron Microscopy) measurements. The Sm -> Ca substitution (Bi(1.)6Pb(0.4)Sr(2)Ca(2-x)Sm(x)Cu(3)O(y)) was carried out by conventional solid-state reaction method. The susceptibility measurements were carried out at different values of the AC field amplitudes. The imaginary part of susceptibility is used to estimate the intergranular critical current density by means of the Bean's model. The intergranular critical current density (J(c)) of pure sample is found to be about 68 A/cm(2) at 95 K. The intergranular J(c) is seen to decrease with increasing Sm substitution. XRD pattern and SEM micrographs are given to provide information about Bi-2223 phase and grain size respectively

Effect of yttrium doping on structural and electrical properties of Bi2Sr1.9Ca0.1−xYxCu2O7+δ (Bi-2202) cuprate ceramics

In this work, we report on the effect of Y3+ doping on structural, mechanical and electrical properties of Bi-2202 phase. Samples of Bi2Sr1.9Ca0.1−xYxCu2O7+δ with x = 0, 0.025, 0.05, 0.075 and 0.10 are elaborated in air by conventional solid state reaction and characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM) combined with EDS spectroscopy, density, Vickers microhardness and resistivity measurements. A good correlation between the variations of the bulk density and the Vickers microhardness with doping is obtained. The SEM photograph shows that the samples are composed of grains with a flat shape that characterizes the Bi-based cuprates. Quantitative EDS analysis confirms the reduction of Ca content and the increase of Y content when x is increased. The variation of resistivity with temperature shows that only samples with x = 0, 0.025 and 0.05 present an onset transition to the superconducting state. The higher onset transition temperature is obtained for x = 0.025 and is about 93.62 K. The transition is wide and is realized in two steps confirming then the presence of the low Tc Bi-2201 phase in the samples. For x = 0.075 and 0.10, a transition to a semiconducting state is seen at low temperatures. Some physical parameters are extracted from these curves and discussed