Simulation-based Decision Support System for Process Capacity Analysis and Workload Balancing

Sudipta Saha,Sangyun Choe,Jinwoo Park 대한산업공학회 2016 대한산업공학회 추계학술대회논문집 Vol.2016 No.11

X-ray 영상을 위한 Lu2Gd1Ga2Al3O12: Ce3+ 형광체의 연구

오명진,SAHA SUDIPTA,김홍주 한국물리학회 2022 새물리 Vol.72 No.9

Ce3+-doped Lu2Gd1Ga2Al3O12 phosphor is fabricated by solid-state reaction method using an electric furnace at 1500 °C for 12 hours and measured by an X-ray diffractometer (XRD) and a field emission scanning electron microscope (FE-SEM) to confirm the crystalline structure. The luminescence properties for UV and X-ray is investigated using X-ray and UV sources, respectively. The emission wavelength of the Ce3+-doped Lu2Gd1Ga2Al3O12 phosphor for UV and X-ray is confirmed at 525 nm because of 2D5/2 to 2F5/2 transition. This wavelength is coincident with yellow color in the CIE chromaticity diagram. The rare earth element-containing phosphors have a high absorption efficiency for X-ray and gamma-ray because of their high atomic Z numbers (Zeff = 55); therefore, they have an advantage for medical imaging fields using X-ray and gamma-ray. 고상 반응법을 이용하여 Ce3+ 을 도핑한 Lu2Gd1Ga2Al3O12 형광체를 전기로에서 1500 °C 에서 12 시간 동안 소결하여 제조하였다. 소결한 형광체의 결정구조를 확인하기 위하여 X-ray diffractometer (XRD) 와 FE-SEM (field emission scanning electron microscope) 을 측정하였으며 UV와 X-선을 이용하여 형광체의 발광 특성을 조사하였다. UV와 X-선을 이용한 Lu2Gd1Ga2Al3O12: Ce3+ 형광체의 발광 파장은 2D5/2 에서 2F5/2 의 천이로 인해 525 nm 에서 넓은 밴드가 나타났으며 CIE chromaticity diagram 에서 보여지듯 노랑색 영역에서 발광한다. 희토류 원소로 구성된 형광체는 유효 원자 번호가 높기 때문에 X-선 및 감마선에 높은 흡수 효율을 가진다. 따라서 X-선 및 감마선을 사용하는 의료영상 분야에 적용할 수 있는 장점이 있다.

Synthesis, characterization and As(III) adsorption behavior of β-cyclodextrin modified hydrous ferric oxide

Indranil Saha,Uday Chand Ghosh,Kaushik Gupta,Sudipta Chakraborty,Debashis Chatterjee 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4

This study investigates the adsorption of As(III) on b-cyclodextrin modified hydrous ferric oxide (HCC). This is characterized by XRD, FESEM, AFM, XPS, BET, surface site concentration and FTIR. The modification of hydrous ferric oxide (HFO) surface by b-cyclodextrin provides ample –OH groups which in turn increase As(III) adsorption on HCC compared to HFO. The adsorption remains almost constant in pH range 3–8 which decreases at higher pH (>8) and followed monolayer and pseudo first order kinetics. It is spontaneous at 303 K with increasing entropy and decreasing enthalpy. Thus HCC is found to be more efficient adsorbent than HFO.

The luminescence properties of Eu3+ or Tb 3+ doped Lu2Gd1Ga2Al3O12 phosphors for X-ray imaging

오명진,Saha Sudipta,김홍주 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.12

The Tb3+ or Eu3+-doped Lu2Gd1Ga2Al3O12 phosphor were fabricated by funace at 1500 ◦C for 12 h using a solid state reaction. The XRD (X-ray diffraction_Panalytical X’Pert Pro) and FE-SEM (field emission scanning electron microscope) are measured to confirm the crystalline structure and surface morphology of the phosphor. The Tb3+-doped Lu2Gd1Ga2Al3O12 phosphor emits the lights in 470~650 nm wavelength range due to transitions from 5D4 to 7Fj.Therefore, it shows the green region in the CIE chromaticity diagram under both UV and X-rays excitations. The Eu3+-doped Lu2Gd1Ga2Al3O12 phosphor emits the lights in 550~750 nm wavelength range because of 5Di to 7Fj. The emission is confirmed to be in the red region using the CIE chromaticity diagram. The Tb3+ or Eu3+-doped Lu2Gd1Ga2Al3O12 phosphor shows the characteristic f-f transition with a long decay time, which is about several milliseconds. They have the high efficiency of light emission for X-ray because of their high effective Z number (Zeff = 58.5) and density. Therefore, they are very much promising phosphors for X-ray imaging application in medical fields.

Radio-Photoluminescence of Silver-Doped Phosphate Glass

Pabitra Aryal,김홍주,Sudipta Saha,Jin Jegal,Quoc Vuong Phan,강상준 한국물리학회 2019 새물리 Vol.69 No.7

Commercial silver-doped phosphate glass is a promising material for a solid-state radiophotoluminescent (RPL) dosimeter. It has several promising characteristics, such as RPL intensity linearity with the ionizing irradiation dose, data accumulation, no fading, and measurement repeatability. It can be used as personal, environmental, and clinical dosimeter as well. The objective of this study was to synthesize silver-doped phosphate glass in the laboratory and compare its RPL properties with those of a commercial GD-352M glass. The emission and the excitation properties of the synthesized and commercial glasses were measured before and after X-ray irradiation. An intense orange emission peak at 600 nm and an excitation peak at 320 nm were measured for the synthesized glass after X-ray irradiation. The radiative lifetime of the synthesized glass had two decay components for the orange Radio-Photoluminescence

The Luminescence Properties of Sm3+ or Tb3+ {doped Lu3Ga2Al3O12 Phosphors for X-ray Imaging

M. J. Oh,Sudipta Saha,H. J. Kim 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.75 No.12

Sm$^{3+}$ or Tb$^{3+}$ -doped Lu$_3$Ga$_2$Al$_3$O$_{12}$ phosphors were synthesized by using a solid-state reaction method with Lutetium oxide, gallium oxide and aluminum oxide as host materials, samarium oxide and terbium oxide as doping materials. The mixed powders were sintered at 1500 $^\circ$C for 5 hours by using a horizontal furnace. In this study, the structures of Sm$^{3+}$ or Tb$^{3+}$ -doped Lu$_3$Ga$_2$Al$_3$O$_{12}$ phosphors were observed using an XRD (X-ray diffraction). The emission spectrum of Sm$^{3+}$ -doped Lu$_3$Ga$_2$Al$_3$O$_{12}$ phosphor shows 550$\sim$650 nm in wavelength due to $^4$G$_{\rm j}$ to $^6$H$_{\rm j}$. The measurement of emission spectrum of Tb$^{3+}$ -doped Lu$_3$Ga$_2$Al$_3$O$_{12}$ phosphor was confirmed to 450 to 650 nm wavelength due to $^5$D$_{\rm j}$ to $^7$F$_{\rm j}$. These phosphors have a sharp emission spectrum due to their physical properties of f-f transition. The Lu$_3$Ga$_2$Al$_3$O$_{12}$ has a high effective Z-number ($Z_{\rm eff}$ = 57) which is sensitive to X-ray or $\gamma$-ray. Therefore Sm$^{3+}$ or Tb$^{3+}$ -doped Lu$_3$Ga$_2$Al$_3$O$_{12}$ phosphors can be applied for diagnostic X-ray imaging in the medical field.

Investigation of the Luminescence Properties of Dy3+ doped Lu3Ga2Al3O12 Phosphors for X-ray Imaging and White LEDs

Oh M. J.,Saha Sudipta,Kim H. J. 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.12

In this research, Dy3+-doped Lu3Ga2Al3O12 phosphor was synthesized by using the combustion method with a solid state reaction at 1500 °C for 12 hours in a furnace. Host materials such as Lu2O3, Ga2O3, Al2O3 and activator such as Dy2O3 were used. The crystal structure and the lattice constants were confirmed by using X-ray diffraction. The emission spectrum of the Dy3+-doped Lu3Ga2Al3O12 phosphor under excitations by UV light and X-rays showed peaks at 482 nm, 580 nm, 670 nm and 760 nm due to electron transitions from the 4F9/2 to the 6Hj orbited. The Lu3Ga2Al3O12:Dy3+ phosphor emits blue, green-yellow and red light when excited by UV light and X-rays. The CIE chromaticity diagram for the emission spectrum gives a color close to white, which indicates that Dy3+-doped Lu3Ga2Al3O12 phosphor may be a good material for use in a light-emitting diode. The Lu3Ga2Al3O12:Dy3+ phosphor has a high sensitivity to X-rays and gamma rays because of its high Z-number (Zeff = 57) and density. Therefore, the Lu3Ga2Al3O12:Dy3+ phosphor can be applied for X-ray imaging in medical fields.

Structural Characteristics, Fluorescence Quenching, and Antioxidant Activity of the Arabinogalactan Protein-rich Fraction from Senna (Cassia angustifolia) Leaves

Sharmistha Sinha,Shruti S. Bandyopadhyay,Debjani Ghosh,Udipta Ranjan Chatterjee,Sudipta Saha,Pradyot K. Ghosal,Bimalendu Ray 한국식품과학회 2011 Food Science and Biotechnology Vol.20 No.4

Senna (Cassia angustifolia) is widely used in Indian folk medicine for the prevention of various disorders. Herein, we have demonstrated that water extracted arabinogalactan protein (AGP) rich fraction possesses strong antioxidative activity. The AGP rich fraction was analyzed using chemical, chromatographic, and spectroscopic methods. Effect of water extracted polymers on bovine serum albumin spectrum was determined using excitation wavelength of 282 nm. The antioxidant capacity of this fraction was studied by ferric reducing antioxidant power (FRAP) and DPPH radical assays. This polymeric fraction,≥88% of which gets precipitated with Yariv reagent,consisted mainly of (1→5)-/(1→3,5)-linked α-arabinosyl,(1→3)-/(1→3,6)-linked-galactosyl residues and terminal arabinofuranosyl residues. Its in vitro antioxidant capacity is comparable to that of standard antioxidants. Fluorescence quenching studies furnishes evidence for the interaction of the arabinogalactan protein with bovine serum albumin.