• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4571-4584
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• 2022

The analysis of rapid flow transients in Reactor Coolant Pumps (RCP) is essential for a reactor safety study. An accurate and precise analysis of the RCP coastdown is necessary for the reactor design. The coastdown of RCP affects the coolant temperature and the colloidal crud in the primary coolant. A realistic and kinetic model has been used to investigate the behavior of activated colloidal crud in the primary coolant and steam generator that solves the pump speed analytically. The analytic solution of the non-dimensional flow rate has been determined by the energy ratio β. The kinetic energy of the coolant fluid and the kinetic energy stored in the rotating parts of a pump are two essential parameters in the form of β. Under normal operation, the pump's speed and moment of inertia are constant. However, in a coastdown situation, kinetic damping in the interval has been implemented. A dynamic model ACCP-SMART has been developed for System Integrated Modular and Advanced Reactor (SMART) to investigate the corrosion due to activated colloidal crud. The Fickian diffusion model has been implemented as the reference corrosion model for the constituent component of the primary loop of the SMART reactor. The activated colloidal crud activity in the primary coolant and steam generator of the SMART reactor has been studied for different equilibrium corrosion rates, linear increase in corrosion rate, and dynamic RCP coastdown situation energy ratio b. The coolant specific activity of SMART reactor equilibrium corrosion (4.0 mg s^-1) has been found 9.63×10^-3 µCi cm^-3, 3.53×10^-3 µC cm^-3, 2.39×10^-2 µC cm^-3, 8.10×10^-3 µC cm^-3, 6.77× 10^-3 µC cm^-3, 4.95×10^-4 µC cm^-3, 1.19×10^-3 µC cm^-3, and 7.87×10^-4 µC cm^-3 for ²⁴Na, ⁵⁴Mn, ⁵⁶Mn, ⁵⁹Fe, ⁵⁸Co, ⁶⁰Co, ⁹⁹Mo, and ⁵¹Cr which are 14.95%, 5.48%, 37.08%, 12.57%, 10.51%, 0.77%, 18.50%, and 0.12% respectively. For linear and exponential coastdown with a constant corrosion rate, the total coolant and steam generator activity approaches a higher saturation value than the normal values. The coolant and steam generator activity changes considerably with kinetic corrosion rate, equilibrium corrosion, growth of corrosion rate (ΔC/Δt), and RCP coastdown situations. The effect of the RCP coastdown on the specific activity of the steam generators is smeared by linearly rising corrosion rates, equilibrium corrosion, and rapid coasting down of the RCP. However, the time taken to reach the saturation activity is also influenced by the slope of corrosion rate, coastdown situation, equilibrium corrosion rate, and energy ratio β.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.6
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• pp.283-290
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• 2013

A stoichiometric mixture of evaporating materials for $MgGa_2Se_4$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $MgGa_2Se_4$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperatures were $610^{\circ}C$ and $400^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by double crystal X-ray diffraction (DCXD). The temperature dependence of the energy band gap of the $MgGa_2Se_4$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=2.34 eV-(8.81{\times}10^{-4}eV/K)T^2/(T+251K)$. The crystal field and the spin-orbit splitting energies for the valence band of the $MgGa_2Se_4$ have been estimated to be 190.6 meV and 118.8 meV, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}_5$ states of the valence band of the $MgGa_2Se_4$/GaAs epilayer. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1^-}$, $B_{1^-}$exciton for n = 1 and $C_{27}-exciton$ peaks for n = 27.

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.418-429
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• 2011

Novel chromium(III), manganese(II), iron(III), cobalt(II), nickel(II), copper(II), ruthenium(III), and zirconyl(II) complexes of $N^1,N^2$-bis(3-((3-hydroxynaphthalen-2-yl)methylene-amino)propyl)phthalamide ($H_4L$, 1) have been synthesized and characterized by elemental, physical, and spectral analyses. The spectral data showed that the ligand behaves as either neutral tridentate ligand as in complexes 2-5 with the general formula $[H_4LMX_2(H_2O)]{\cdot}nH_2O$ (M=Cu(II), Ni(II), Co(II), X = Cl or $NO_3$), neutral hexadentate ligand as in complexes 10-12 with the general formula $[H_4LM_2Cl_6]{\cdot}nH_2O$ (M=Fe(III), Cr(III) or Ru(III)), or dibasic hexadentate ligand as in complexes 6-9 with the general formula $[H_2LM_2Cl_2(H_2O)_4]{\cdot}nH_2O$ (M = Cu(II), Ni(II), Co(II) or Mn(II), and 13 with general formula $[H_4L(ZrO)_2Cl_2]{\cdot}8H_2O$. Molar conductance in DMF solution indicated the non-ionic nature of the complexes. The ESR spectra of solid copper(II) complexes 2, 5, and 6 showed $g_{\parallel}$ >g> $g_e$, indicating distorted octahedral structure and the presence of the unpaired electron in the $N^1,N^2$ orbital with significant covalent bond character. For the dimeric copper(II) complex $[H_2LCu_2Cl_2(H_2O)_4]{\cdot}3H_2O$ (6), the distance between the two copper centers was calculated using field zero splitting parameter for the parallel component that was estimated from the ESR spectrum. The antibacterial and antifungal activities of the compounds showed that, some of metal complexes exhibited a greater inhibitory effect than standard drug as tetracycline (bacteria) and Amphotricene B (fungi).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.5
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• pp.217-224
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• 2008

A stoichiometric mixture of evaporating materials for $ZnIn_2Se_4$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $ZnIn_2Se_4$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperatures were $630^{\circ}C$ and $400^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $ZnIn_2Se_4$ single crystal thin films measured from Hall effect by van der Pauw method are $9.41\times10^{16}cm^{-3}$ and $292cm^2/v{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $ZnIn_2Se_4$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=1.8622eV-(5.23\times10^{-4}eV/K)T^2/(T+775.5K)$. The crystal field and the spin-orbit splitting energies for the valence band of the $ZnIn_2Se_4$ have been estimated to be 182.7 meV and 42.6 meV, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}_5$ states of the valence band of the $ZnIn_2Se_4/GaAs$ epilayer. The three photo current peaks observed at 10 K are ascribed to the $A_{1}-$, $B_{1}-exciton$ for n = 1 and $C_{27}-exciton$ peaks for n = 27.

• Journal of Sensor Science and Technology
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• v.11 no.5
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• pp.309-318
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• 2002

A stoichiometric mixture of evaporating materials for $CdIn_2S_4$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $CdIn_2S_4$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperatures were $630^{\circ}C$ and $420^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CdIn_2S_4$ single crystal thin films measured with Hall effect by van der Pauw method are $9.01{\times}10^{16}\;cm^{-3}$ and $219\;cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $CdIn_2S_4$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=2.7116\;eV-(7.74{\times}10^{-4}\;eV)T^2/(T+434)$. The crystal field and the spin-orbit splitting energies for the valence band of the $CdIn_2S_4$ have been estimated to be 0.1291 eV and 0.0248 eV, respectively, by means of the photocurrent spectra and the Hopfield quasi cubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}5$ states of the valence band of the $AgInS_2$/GaAs epilayer. The three photocurrent peaks observed at 10K areascribed to the $A_1$-, $B_1$-, and C1-exciton peaks for n = 1.

• Journal of Food Hygiene and Safety
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• v.26 no.3
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• pp.273-282
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• 2011

This study established hazards which may cause risk to human at farm during cultivation stage of paprika. Samples of plants (paprika, leaf, stem), cultivation environments (water, soil), personal hygiene (hand, glove, clothes), work utensils (carpet, basket, box) and airborne bacteria were collected from three paprika farms (A, B, C) located in Western Gyeongnam, Korea. The collected samples were assessed for biological (sanitary indications and major foodborne pathogens), chemical (heavy metals, pesticide residues) and physical hazards. In biological hazards, total bacteria and coliform were detected at the levels of 1.9~6.6 and 0.0~4.610g CFU/g, leaf, mL, hand or 100 $cm^2$, while Escherichia coli was not detected in all samples. In major pathogens, only Bacillus cereus were detected at levels of ${\leq}$ 1.5 log CFU/g, mL, hand or 100 $cm^2$, while Staphylococuus aureus, Listeria monocytogenes, E. coli O157 and Salmonella spp. were not detected in all samples. Heavy metal and pesticide residue as chemical hazards were detected at levels below the regulation limit, physical hazard factors, such as insects, pieces of metal and glasses, were also found in paprika farms. Proper management is needed to prevent biological hazards due to cross-contamination while physical and chemical hazards were appropriate GAP criteria.

• Journal of the Mineralogical Society of Korea
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• v.5 no.2
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• pp.109-121
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• 1992

For the purpose of mineralogical and chemical study on the topazes from various localities of world(Brzail, China, India, Nigeria and Sri Lanka), electron microprobe analysis(EPMA), neutron activation analysis(NAA), X-ray diffractometry, Raman spectroscopy, etch test, scanning electron microscopy, refractive index, specific gravity, fluid inclusion were performed. The chemical composition in topaz was discussed along with its physical and structural properties. Variations in the unit-cell dimension and physical properties of topaz were found to have a close relations in the unit-cell dimension and physical properties of topaz were found to have a close relationship with extent of substitution of $OH^-\;for\;F^-$. According to neutron activation analyses, the trace elements had no effects on the physical properties of topaz. Raman spectra showed that the peaks of topaz were different in intensity from one locality to another. Etching defects in topaz includes negative crystal defect o point-bottom pit(India, Nigeria) and net work defect of curl-bottom pit(Brazil, China). Fluid inclusions in topaz may be classiffied into liquid $CO_2$-bearing inclusion, gaseous inclusion, halite, sylvite-bearing inclusion and liquid inclusion. The results of this study can be useful to devising artificial coloring methods for topaz with different mineralogical compositions.

• Analytical Science and Technology
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• v.23 no.5
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• pp.485-491
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• 2010

A certified reference material (CRM) of KRISS 109-03-SSD was developed for the analysis of hazardous elements in soil. The target elements were As, Cd, Cr, Cu, Hg, Ni, Pb, Zn being regulated by the Soil Environment Conservation Act. Starting material was collected from tailing dump of an unworked tungsten mine at Sangdong (Gangwon-do, Korea). The starting material under-went through a series of fabricating process steps of screening, drying, grinding, sieving, blending, bottling, sterilization and was certified according to the ISO Guide 35. Isotope dilution-inductively coupled mass spectrometry (ID-ICP/MS) and instrumental neutron activation analysis (INAA) were used for the measurement. Homogeneity was tested according to ISO 13528 annex B. The certified values were determined using the results from two different methods or from two independent measurements using a method. Finally, certified values of seven elements of arsenic, cadmium, chromium, copper, lead, nickel and zinc were determined. Mercury did not satisfied the criteria of homogeneity and the result would be provided for information only, together with iron and tungsten. It was also studied, the extractable fraction of elements by aqua regia according to the ISO 11466 protocol being frequently studied for the purpose of environmental monitoring. It was performed as a inter-laboratory study by 6 laboratories of a public institute and universities. Standard deviation among the laboratories was much bigger than the uncertainty of the certified value. The result of inter-laboratory study on the extractable fraction will be provided for information, only.

• Radiation Oncology Journal
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• v.22 no.3
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• pp.177-183
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• 2004

Purpose: Authors would report the results of sequential CHOP chemotherapy (cyclophosphamide, adriamycin, vincristine, and prednisone) and involved field radiotherapy (IFRT) for early stage nasal natural killer/T-cell Iymphoma (NKTCL). Materials and Methods: Fourteen among 17 patients, who were registered at the Samsung Medical Center tumor registry with stage I and II nasal NKTCL from March 1995 to December 1999 received this treatment protocol. Three to four cycles of CHOP chemotherapy were given at 3 weeks' interval, which was followed by local IFRT including the known tumor extent and the adjacent draining lymphatics. Results: Favorable responses after chemotherapy (before IFRT) were achievable only in seven patients (5 CR's+2 PR's: 50%), while seven patients showed disease progression. There were six patients with local failures, two with distant relapses, and none with regional lymphatic failure. The actuarial overall survival and progression-free survival at 3 years were 50.0% and 42.9%. All the failures and deaths occurred within 13 months of the treatment start. The factors that correlated with the improved survival were the absence of 'B' symptoms, the favorable response to chemotherapy and overall treatment, and the low risk by international prognostic index on univariate analyses. Conclusion: Compared with the historic treatment results by IFRT either alone or followed by chemotherapy, the current trial failed to demonstrate advantages with respect to the failure pattern and survival. Development of new treatment strategy in combining IFRT and chemotherapy is required for improving outcomes.

• Journal of Life Science
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• v.27 no.2
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• pp.217-224
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• 2017

Carbon monoxide (CO), a reaction product of cytoprotective enzyme heme oxygenase-1 (HO-1), is a gaseous messenger with anti-proliferative, anti-apoptotic, and anti-inflammatory actions in many cell types. Here, we investigated the role of CO on the process of monocyte differentiation induced by phorbol 12-myristate 13-acetate (PMA) in human monocytic THP-1 cells. CORM-2 (tricarbonyldichlororuthenium (II) dimer, $Ru2Cl_4(CO)_6$), a CO-releasing compound, decreased a marked cell adherence with a slight reduction of proliferation in monocytic THP-1 cells treated with PMA. And, CORM-2 significantly inhibited expression of differentiation markers such as CD14, CD11b plus CD18 (macrophage-1 antigen, Mac-1 or complement receptor 3, CR3) and phagocytosis of carboxylate-modified red fluorescent latex beads, in PMA-stimulated THP-1 cells. For the further experiments, differentiation of PMA-treated cells was enhanced after the initial 2 days stimulus by removing the PMA-containing media then incubating the cells in fresh media for a another 4 days. And, we observed the secretion of inflammatory cytokines and phagocytosis in differentiated macrophages. Treatment with CORM-2 significantly abolished the secretion of IL-6, $TNF-{\alpha}$ and phagocytosis using fluorescence-conjugated E. coli (K-12 strain) bioparticles in lipopolysaccharide (LPS)-stimulated differentiated macrophages. In conclusion, these results suggest that CO inhibits the differentiation of monocytic THP-1 cells as well as the activation of differentiated macrophages.