Neutron Scattering Studies of the Magnetic Fluctuations in YBa_2Cu_3O_{7-\delta}

Neutron scattering measurements have been made on the spin fluctuations in YBa_2Cu_3O_{7-\delta} for different oxygen doping levels. Incommensurability is clearly observed for oxygen concentrations of 6.6 and 6.7 and is suggested for the 6.93. Measurements of the resonance for the O_{6.6} concentration show that it exists in a broadened and less intense form at temperatures much higher than T_c.Comment: 9 pages, 4 gif figures, Proceedings of Spectroscopies in Novel Superconductors, Cape Cod, Massachusetts, Sept, 199

İnce Kirişlerin Elastik Davranışlarının NIY ve RNIY Yöntemleri İle İncelemesi

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2013Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2013Bu çalışmada, ince kirişlerin elastik davranışlarının incelenmesi, ağsız yöntemlerden olan Noktasal İnterpolasyon (NİY) ve Radyal Noktasal İnterpolasyon (RNİY) yöntemleri ile gerçekleştirilmiştir. Her bir yöntemde, iki farklı integrasyon tekniği kullanılmıştır. Standard olarak kullanılan Gauss integrasyon tekniği, Taylor noktasal integrasyon tekniği ile karşılaştırılmış, NİY ve RNİY üzerine etkileri araştırılmıştır. Noktasal direngenlik matrisinin elde edilmesi, Bernoulli-Euler kiriş teorisine göre gerçekleştirilmiştir. Farklı etki alanı büyüklükleri ve farklı RNİY şekil parametrelerinin çözümler üzerine etkileri ayrıca ele alınmıştır. Bir ankastre kiriş problemi, serbest uca tekil yük uygulanarak çözülmüştür. Elde edilen çözümler, ANSYS paket programı kullanılarak sonlu elemanlar yöntemiyle kıyaslanmıştır.In this study, the point interpolation method (PIM) and radial point interpolation method (RPIM) solutions of elastic thin beams are compared by using standard Gaussian integration and a nodal integration based on Taylor series expansion. The effects of integration schemes, support domain sizes and RPIM shape parameters on the convergency are also investigated. Nodal stiffness matrices are obtained using Bernoulli-Euler beam theory. A cantilever beam problem with concentrated load applied on one end is solved and the results are compared with finite element solutions in ANSYS

Three-dimensional modelling and morphometric investigation of computed tomography images of brown bear’s (Ursus arctos) ossa cruris (Zeugopodium)

Background: This study was aimed to examine the detailed morphometrical and morphological characteristics of the bone by creating three-dimensional images through multidetector computed tomography images of ossa cruris in brown bears.Materials and methods: Four brown bear ossa cruris were used in the study.Results: It was observed that tibia and fibula articulated at proximal and distal epiphysis and they combined, and ossa cruris were shaped in this way. Cochlea tibiae were determined to be sagittally oriented. The length of the tibia was determined to be 268.97 mm and 266.32 mm at right and left sides, respectively. The length of the fibula was determined to be 249.16 mm and 250.19 mm on average at the right and left sides, respectively. In consequence of the correlation analysis, statistical relationships at different rates were detected between themeasured values.Conclusions: Detailed anatomical examinations are very important in terms of determining the similarities and differences of bear bones with those of the other species in the order Carnivora. Therefore, it is thought that this study will reveal detailed characteristics of ossa cruris of bears and provide data for further studies on archaeological and forensic sciences

Electron and Spin Transport in the Presence of Complex Absorbing Potential

We examine the impact of a complex absorbing potential on electron transport, both in the continuum and on a lattice. This requires the use of non-Hermitian Hamiltonians; the required formalism is briefly outlined. The lattice formulation allows us to study the interesting problem of an electron interacting with a stationary spin, and the subsequent time evolution of the electron and spin properties as the electron is absorbed after the initial interaction. Remarkably, the properties of the localized spin are affected 'at-a-distance' by the interaction of the (now entangled) electron with a complex potential.Comment: to be published in Phys. Rev.

INVESTIGATING HOW PARENTS, WHO GUIDE THEIR PRESCHOOL CHILDREN TOWARDS SPORTS, PERCEIVE SPORTS ACTIVITIES

Objectives: The aim of this study was to investigate parents’ expectations about general sport activities for their pre-school children. It is well documented that the awareness of sports knowledge of the parents are essential for the development of healthy life and acquiring a social dimension with a growth of healthy generations. Method: We administrated the ‘’Parents' Expectations of Their Children Questionnaire’’ developed by Keskin (2006). The questionnaire was a Likert type scale from ‘’totally agree’’ to ‘’totally disagree’’ and validity and reliability studies were reported by Keskin as Cronbach’s alpha was 0,86. A total of 125 participants (male; N = 39, Mage=35, 24 ± 5,48 , female; N = 86 and Mage=37,92 ± 6,65) were voluntarily participated from 10 different kinder gardens in Bursa province. The evaluation of the data was analysed with the Chi Square Test. Result: Our results revealed a statistical differences (p < .05) according to the sex groups of parents ‘’I believe my child will gain good eating habits by getting involved with sports activities’’ and age groups of parents; ‘’I believe by getting involved with sport activities, my child will stay away from psychological stress’’. Conclusion: According to parents’ belief and their expectations, attending sports activities for children provides physical, cognitive and social development for them. Developing countries (as well as developed ones) that are aware of the role of the parents on development of human being via sport and exercise activities should take into account their expectations especially in terms of sports policies.  Article visualizations

Observation of Magnetic Moments in the Superconducting State of YBa2_2Cu3_3O6.6_{6.6}

Neutron Scattering measurements for YBa$_2$Cu$_3$O$_{6.6}$ have identified small magnetic moments that increase in strength as the temperature is reduced below $T^\ast$ and further increase below $T_c$. An analysis of the data shows the moments are antiferromagnetic between the Cu-O planes with a correlation length of longer than 195 \AA in the $a$-$b$ plane and about 35 \AA along the c-axis. The origin of the moments is unknown, and their properties are discusssed both in terms of Cu spin magnetism and orbital bond currents.Comment: 9 pages, and 4 figure

The effect of hydrogen etching on 6H-SiC studied by temperature-dependent current-voltage and atomic force microscopy

6H–SiC was etched with hydrogen at temperatures between 1000 and 1450°C. The etchedSi-terminated face for the 6H‐SiC wafer was investigated by atomic force microscopy and temperature-dependent current–voltage (I–V–T)measurements. Mechanical polishing damage was effectively removed by hydrogen etching at temperatures above 1250°C. Atomic force microscopy images revealed that very good surface morphology, atomic layer flatness, and large and large step width were achieved. Schottky diode characteristics were investigated in detail by current–voltage and temperature-dependent current–voltage measurements, and the results showed a transition from defect assisted tunneling to thermionic emission as the annealingtemperature was increased from 1250 to 1450°C

Effect of n+-GaN subcontact layer on 4H–SiC high-power photoconductive switch

High-power photoconductive semiconductor switching devices were fabricated on 4H–SiC. In order to prevent current crowding, reduce the contact resistance, and avoid contact degradation, a highly n-doped GaN subcontact layer was inserted between the contact metal and the high resistivity SiC bulk. This method led to a two orders of magnitude reduction in the on-state resistance and, similarly, the photocurrent efficiency was increased by two orders of magnitude with the GaN subcontact layer following the initial high current operation. Both dry etching and wet etching were used to remove the GaN subcontact layer in the channel area. Wet etching was found to be more suitable than dry etching

Determination of periodic deformation from InSAR results using the FFT time series analysis method in Gediz Graben

Permanent Scatterers (PS) point velocities obtained by the interferometric synthetic aperture radar (InSAR) method are generally determined using the linear regression model, which ignores periodic and seasonal effects. In this study, software was developed that can detect periodic effects by applying fast Fourier transformation (FFT) time series analysis to InSAR results. Using the FFT time series analysis, the periodic components of the surface movements at the PS points were determined, and then the annual velocity values free from periodic effects were obtained. The study area was chosen as the Gediz Graben, a tectonically active region where aseismic surface deformations have been observed in recent years. As a result, using the developed method, seasonal effects were successfully determined with the InSAR method at the PS points in the study area with a period of 384 days and an average amplitude of 19 mm. In addition, groundwater level changes of a water well in the region were modeled, and 0.93 correlation coefficient values were calculated between seasonal InSAR displacement values and water level changes. Thus, using the developed methodology, the relationship between the tectonic movement in the Gediz Graben in Turkey and the seasonal movements and the change in the groundwater level was determined