http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Amir Ullah,Muneeb-ur-Rahman,Muhammad Javid Iqbal,Chang Won Ahn,Ill Won Kim,Aman Ullah 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.12
The electrical properties of the 0.925(Bi0.5(Na0.40K0.10)TiO3-0.075(Ba0.70Sr0.30)TiO3 (0.925BNKT-0.075BST) ceramic were investigated by using AC impedance spectroscopy over a wide range of frequencies (10−2 105 Hz). The X-ray diffraction patterns confirmed the formation of a single-phase compound. A single semicircular arc in the impedance spectrum indicates that the main contribution of the bulk resistance (Rb) were due to grain effects, with Rb decreasing with increasing temperature. The conductivity of the ceramics increased with increasing temperature, and the activation energy resulting from the DC conductivity was 0.86 eV. The ceramic displayed a typical negative temperature coefficient of resistance (NTCR) behavior, like that of a semiconductor.
Dielectric and Electromechanical Properties of Zr-Doped BNT-ST Lead-Free Piezoelectric Ceramics
Amir Ullah,Mateen Ullah,Aman Ullah,A. V. Trukhanov,Ghulam Saddiq,Burhan Ullah,Aurang Zeb,Saeed Ullah Jan,김일원 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.74 No.6
0.72(Bi$_{0.5}$Na$_{0.5}$)Ti$_{(1-x)}$Zr$_x$O$_3$-0.28SrTiO$_3$ (BNTZ-ST) with $x$ = 0.00, 0.01, 0.02 and 0.03 were produced using a solid solution reaction procedure. Results from the X-ray diffraction (XRD) analysis showed the presence of a perovskite structure with cubic symmetry for all samples. Surface analysis was completed using field emission scanning electron microscopy (FE-SEM), and the grain size was found to decrease slightly with increasing Zr doping. The grain morphology was primarily rectangular, but morphed into a rounder shape with increases in Zr. In a dielectric constant study, the depolarization temperature was found to decrease with increasing Zr$^{+4}$ content and increasing frequency. The strain was found to be 0.34\% for the undoped samples with an equivalent dynamic strain ($S_{max}/E_{max}$) of 618 pm/V, without negative strain. However, the strain decreased slightly and hysteresis loops become slim and more symmetric, attaining a relaxor ferroelectric behavior with increasing Zr content.
Ozer, Zafer,Kurtoglu, Cem,Mamedov, Amirullah M.,Ozbay, Ekmel Korean Academy of Dental Science 2015 Journal of korean dental science Vol.8 No.1
Purpose: To investigate the influence of crown margin design on the stress distribution and to localize critical sites in maxillary canine under functional loading by using three dimensional finite element analysis. Materials and Methods: The bite force of 100 N, 150 N, and 200 N was applied with an angulation of $45^{\circ}$ to the longitudinal axis of tooth. Six models were restored with IPS e.max (Ivoclar Vivadent, Schaan, Liechtenstein) with a different margin design. With lingual ledge and various thicknesses, three different core ceramics were designed in each model. Result: In the core ceramic, the maximum tensile stresses were found at the labiocervical region. In the veneering ceramic the maximum tensile stresses were found at the area where the force was applied in all models. Conclusion: Shoulder and chamfer margin types are acceptable for all-ceramic rehabilitations. A ledge on the core ceramic at cervical region may affect the strength of all-ceramic crowns.