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ANALISIS PARAMETER MIKROSTRUKTUR NANOPARTIKEL Mn1-xZnxFe2O4 BERDASARKAN POLA DIFRAKSI SINAR X Indrayana, I Putu Tedy
JST (Jurnal Sains dan Teknologi) Vol. 8 No. 1 (2019)
Publisher : Universitas Pendidikan Ganesha

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1488.068 KB) | DOI: 10.23887/jstundiksha.v8i1.13016

Abstract

The Mn-Zn Ferit is a magnetic material which has potential applications for data storage device, the inductor coil and catalysis. This material has unique electrical and optical properties. Their properties are microstructural dependent. In this work, we studied the microstructural parameters of Mn1-xZnxFe2O4 which x assigns the mole fraction of Mn2+ and Zn2+ (x = 0.6; 0.7 and 0.8). Samples were synthesized by using coprecipitation method and NaOH as a coprecipitant. Microstructural parameters were investigated based on X-ray diffraction pattern. The crystallite size and strain were determined by using Size-strain plot (SSP) method. The crystallite size of nanoparticles is in a range of 18.9 nm – 24.8 nm, while the strain is in a range of 0.0012 – 0.0099. The lattice parameter is in a range of 8.531Ǻ - 8.567Ǻ bigger than the values were calculated theoretically according to the theoretical cation distribution model. The cation distribution in crystal lattice takes important rule in determining the microstructural parameters of nanoparticles. 
PARTICLES SIZE AND LATTICE STRAIN EFFECT ON THE OPTICAL CONSTANTS OF Fe3O4 NANOPARTICLES Indrayana, I Putu Tedy; Tuny, Margaretha Tabita
Indonesian Physical Review Vol. 4 No. 1 (2021)
Publisher : Universitas Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/ipr.v4i1.71

Abstract

In the case of optical sensors such as the Surface Plasmon Resonance (SPR) sensor, the Fe3O4 nanoparticles play a role to boost the signal however they can increase the detection sensitivity of the biosensor. For this application, the optical properties of Fe3O4 nanoparticles need to be studied. The optical properties are described in terms of their optical constants. Therefore, this work was purposed to study the effect of the particle size and lattice strain on the optical constants of Fe3O4 nanoparticles. Samples were synthesized by using the coprecipitation technique. Two calcination temperatures, i.e., 150oC and 250oC for 4 hours were applied to the samples. Samples were characterized for their diffraction pattern and optical properties by using XRD and Specular UV-Vis Spectroscopy technique, consecutively. The particle size and lattice strain were estimated by using the Williamson-Hall (W-H) method. The effect of the particle size and their optical constants on the reflectance curve in the SPR sensor application was also performed toward a simulation by using Winspall 3.02 software. The results show that calcination temperature causes an increase in particle size and a decrease in lattice strain. The optical constants, such as absorbance (A), absorption coefficient (α), extinction coefficient (k), refractive index (n), dielectric constants (ε), optical conductivity (σ), and the Urbach energy (Eu) significantly depended on particles size and lattice strain. However, the particle size and optical constant were significantly influent the SPR angle in the reflectance curve of Fe3O4
Variasi Parameter Filed of View (FoV) terhadap Nilai Signal to Noise Ratio (SNR) Dan Contras to Noise Ratio (CNR) pada Pemeriksaan Lumbal Dengan Potongan Axial Zofi Dwi Prihatini; Ni Nyoman Ratini; I Putu Tedy Indrayana; Gusti Ngurah Sutapa; I Wayan Supardi; I Gde Antha Kasmawan
Kappa Journal Vol 9 No 3 (2025): Kappa Journal
Publisher : Universitas Hamzanwadi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29408/kpj.v9i3.33351

Abstract

Magnetic Resonance Imaging (MRI) is widely used to evaluate spinal pathology, with image quality strongly influenced by acquisition parameters such as the Field of View (FOV). This study investigates the effect of small FOV adjustments on the Signal-to-Noise Ratio (SNR) and Contrast-to-Noise Ratio (CNR) in axial T2-weighted Fast Spin Echo (FSE) lumbar spine MRI. This study offers one of the quantitative evaluations of clinically realistic FOV variations, addressing a gap between routine protocol adjustments and evidence-based image quality optimization. This experimental study prospectively examined thirty patients undergoing routine lumbar spine MRI using a Philips Ingenia CX 1.5T system. Axial T2-weighted FSE images were acquired with three FOV settings (170 mm × 170 mm, 190 mm × 190 mm, and 210 mm × 210 mm), while all other imaging parameters were kept constant. Image quality was assessed by measuring mean signal intensities in standardized regions of interest (ROIs) placed in the intervertebral disc, cerebrospinal fluid (CSF), and surrounding fat tissue, from which SNR and CNR were calculated and statistically compared across FOV settings. The results showed increasing trends in SNR and CNR with larger FOV values; however, these differences were not statistically significant (p > 0.05), indicating that small FOV enlargements produce minimal voxel size changes and negligible effects on image quality. Clinically, these findings suggest that minor FOV adjustments can be safely applied to accommodate patient anatomy or positioning without compromising image quality, while larger FOV changes are required to achieve meaningful improvements in SNR and CNR.