• Clinical and Experimental Pediatrics
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• v.57 no.6
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• pp.278-286
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• 2014

Purpose: To evaluate the potential utility of $^{123}I$-metaiodobenzylguanine ($^{123}I$-MIBG) scintigraphy and $^{18}F$-fluorodeoxyglucose ($^{18}F$-FDG) positron emission tomography (PET) for the detection of primary and metastatic lesions in pediatric neuroblastoma (NBL) patients, and to determine whether $^{18}F$-FDG PET is as beneficial as $^{123}I$-MIBG imaging. Methods: We selected 8 NBL patients with significant residual mass after operation and who had paired $^{123}I$-MIBG and $^{18}F$-FDG PET images that were obtained during the follow-up. We retrospectively reviewed the clinical charts and the findings of 45 paired scans. Results: Both scans correlated relatively well with the disease status as determined by standard imaging modalities during follow-up; the overall concordance rates were 32/45 (71.1%) for primary tumor sites and 33/45 (73.3%) for bone-bone marrow (BM) metastatic sites. In detecting primary tumor sites, $^{123}I$-MIBG might be superior to $^{18}F$-FDG PET. The sensitivity of $^{123}I$-MIBG and $^{18}F$-FDG PET were 96.7% and 70.9%, respectively, and their specificity were 85.7% and 92.8%, respectively. $^{18}F$-FDG PET failed to detect 9 true NBL lesions in 45 follow-up scans (false negative rate, 29%) with positive $^{123}I$-MIBG. For bone-BM metastatic sites, the sensitivity of $^{123}I$-MIBG and $^{18}F$-FDG PET were 72.7% and 81.8%, respectively, and the specificity were 79.1% and 100%, respectively. $^{123}I$-MIBG scan showed higher false positivity (20.8%) than $^{18}F$-FDG PET (0%). Conclusion: $^{123}I$-MIBG is superior for delineating primary tumor sites, and $^{18}F$-FDG PET could aid in discriminating inconclusive findings on bony metastatic NBL. Both scans can be complementarily used to clearly determine discrepancies or inconclusive findings on primary or bone-BM metastatic NBL during follow-up.

• Fire Science and Engineering
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• v.33 no.3
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• pp.51-55
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• 2019

To prevent ozone depletion caused by CFCs, the replacement of Halon with clean agents has been developed in the fire protection field along with refrigerants, detergents, and foaming agents. The alternatives for Halon 1211 have been developed in the portable fire extinguisher area and HCFC-123 is used widely as a clean fire extinguishing agent. The type of expellant gas is important because their own vapor pressure is low. In this study, HCFC-123, HCFC-124, HFC-125, and Novec-1230 were selected as fire extinguishing agents and CO₂, which is expected to improve the fire extinguishing ability, was chosen as the expellant gas. For each agent, experiments changing the agent and CO₂ amount were carried out and HCFC-123 showed a good result, as expected. The extinguisher, HCFC-123 of 1.5 kg, showed the same ability to suppress a class A and B fire as the extinguisher, HCFC-123 of 2.5 kg, which is currently sold on the market. According to this result, the expellant gas has a subsidiary fire extinguish effect. This can reduce the amount of HCFC fire extinguishing agent, which is categorized in the phase-out alternatives, and is a more eco-friendly and economical fire extinguisher than the previous one. This study can also help solve the problems of CO₂ fire extinguishers for class B and C fires, and can be used to extinguish electric and electron facilities fire, which contains large amounts of class A fire combustibles.

• The Korean Journal of Nuclear Medicine
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• v.30 no.4
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• pp.516-523
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• 1996

The purpose of this study was to evaluate the clinical usefulness of I-123 MIBG scintigraphy with early planar and SPECT image in the diagnosis of neuroendocrine tumors. We reviewed I-123 MIBG scintigraphies of 21 patients who had been suspected to have neuroendocrine tumors by CT or MRI findings. Early 4 hour planar and SPECT images were obtained in all patients and delayed (13-24 hour) planar images were performed in 17 patients. Final diagnoses were made by surgery, biopsy, or clinical follow up. Twelve patients were confirmed to have neuroendocrine tumors. With 4 hour planar and SPECT images, there were 9 true positives(6 pheochromocytomas, 1 paraganglioma, 1 neuroblastoma, and 1 medullary cancer of the thyroid), 8 true negatives(1 adrenal cortical adenoma, 1 malignant fibrous histiocytoma, 1 adenoma in colon and 5 benign nonfunctioning adrenal tumors), 1 false positive(hepatocellular carcinoma) and 3 false negatives(1 recurred medullary cancer of the thyroid, 1 liver metastasis of carcinoid tumor and 1 ganglioneuroma). The sensitivity and specificity of I-123 MIBG scintigraphy were 75% and 89%, respectively. SPECT images provided good anatomical correlation with CT or MRI. Delayed images showed increased tumor to background ratio in 5 out of 8 true positive patients, but did not change the diagnosis. In conclusion, early 4 hour images with I-123 MIBG is clinically convenient and useful method in the detection of neuroendocrine tumors, and SPECT images can provide good anatomical correlation with CT or MRI.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.05a
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• pp.3-3
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• 2009

In order to investigate the possibility of using mixed rare earth $(Nd_{1/3}Eu_{1/3}Gd_{1/3})Ba_2Cu_3O_{7-x}$ (NEG123) as the superconducting layer of the HTS coated conductor, the NEG123 thin film was deposited epitaxialy on LAO(100) single crystal and IBAD_YSZ metal templates by pulsed laser deposition. Systematic studies were carried out to investigate the influences of deposition parameters of PLD on the micro structure, texture and superconducting properties of NEG-123 coated conductor. Deposition at oxygen partial pressure of 600 mTorr was needed to routinely obtain high quality NEG123 films with $J_c$'s (77K) over 2 MA/$cm^2$ and Tc's over 90K (${\Delta}T{\sim}2\;K$). We verified from magnetization study that the NEG123 has an improved in-field Jc as the field increases at temperatures between 10 K and 77 K compared with Gd123. The $J_c$ (77K, self field) and the value of onset $T_c$ of NEG123 thin film on LAO substrate was $4.0MA/cm^2$ and 92K, respectively. This is the first report, to the best of our knowledge, of coated conductors with NEG123 film as the superconducting layer which have Ic and Jc over 40 A/cm-width and 1.6 MA/$cm^2$ at 77K, self field. This study shows the possibility of using NEG123 film as the superconducting layer of the HTS coated conductor which can be used in high magnetic field power electric devices.

• Journal of the Korean Chemical Society
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• v.35 no.4
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• pp.316-323
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• 1991

We calculated a difference between the YBa$_2Cu _3O_{7-x}$ superconductor (123 system) of critical temperature, 95 K and the YBa$_2Cu_4 O_8$ superconductors (124 system) of critical temperature, 80 K in Y-system superconductors using Extended Huckel Theory (EHT). The valence electron population (VEP), reduced overlap population (ROP) and net charge for the charged cluster models relating to the layer and the chain in 123 and 124 systems were compared. The VEPs of Cu atom in the layer of 123 and 124 systems populated d$_{z^2}$ orbital more than d$_{x^2-y^2}$ orbital, and in the chain of 123 and 124 systems populated d$_{y^2-z^2}$ orbital more than d$_{z^2}$ orbital. The ROP of the Cu(1)-O(1) in the layer of 123 system was larger than the value of the Cu(1)-O(2), but the ROP of the Cu(1)-O(2) in the layer of 124 system was larger than the value of the Cu(1)-O(1). The ROP of Cu(2)-O(4) in the chain of 123 and 124 systems were larger than the value of the Cu(2)-O(3). In 123 system the net charge values of the Cu in the layer was larger than the value of the Cu in the chain. However, in 124 system the net charge value of the Cu in the chain was larger than the value in the layer.

• Journal of the Korean Solar Energy Society
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• v.30 no.3
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• pp.33-38
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• 2010

The evaporative desalination system using solar thermal energy would be the efficient and attractive method to get fresh water from brine due to low carbon dioxide generation. In this research the solar desalination system as a heating source of refrigerant R123 in the evaporator was considered. The circulation of refrigerant in the evaporator can reduce the energy consumption of the system, because of using the latent heat of the refrigerant 123 instead of the sensible heat of present hot water. The system was comprised of the single-stage fresh water production unit on the capacity of 1ton/day with shell and tube type evaporator, heaters instead of solar collector to supply the proper heat to refrigerant, and refrigerant and brine circulation systems. Various operating flowrate and temperature ranges were varied in the experiments to get the optimum design data. The results showed that the optimum flow rate of brine feed rate to evaporator was 1.2Liter/min, and the yield of fresh water was increased as higher temperature of feed brine. It was confirmed that the circulation flowrate of heating source of refrigerant was decrease of one fifth of the present warm water system, and very efficient system for solar desalination.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.9
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• pp.2316-2327
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• 1995

Experimental results from nucleate pool boiling heat transfer with various finned tubes in CFC11, HCF123 and HCFC141b are reported. One plain tube and four low fin tubes of various fin densities were tested in an attempt to find out the optimum fin density in the heat flux range of 10-60 kW/m$^{[-992]}$ at near atmospheric pressure. The results indicated that CFC11 showed the highest heat transfer coefficients. Its alternatives, HCFC123 and HCFC141b, showed 3-5% lower heat transfer coefficients than those of CFC11 at the same heat flux. As the fin density increases, so does the heat transfer surface area. Measured heat transfer coefficients, however, do not necessarily always increase as the fin density increases. This unique phenomenon seems to be caused by the coalescence of the bubblers that prevent the cool liquid from entering into the fin valleys. For all the refrigerants tested, the optimum fin density yielding the highest performance was 28 fins per inch confirming the previous results by other researchers.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.2
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• pp.87-96
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• 2008

Flow condensation heat transfer coefficients(HTCs) of R123 and R245fa are measured in a horizontal plain tube. The main test section in the experimental flow loop is made of a plain copper tube of 9.52 mm outside diameter and 530 mm length. The refrigerant is cooled by passing cold water through an annulus surrounding the test section. Tests are performed at a fixed saturation temperature of $50\;{\pm}\;0.2\;^{\circ}C$ with mass fluxes of 50, 100, $150\;kg/m^2s$ and heat flux of $7.3{\sim}7.7\;kW/m^2$. Heat transfer data are obtained in the vapor quality range of $10{\sim}90%$. Test results show that the flow condensation HTCs of R245fa are overall 7.9% higher than those of R123 at all mass fluxes. The pressure drop of R245fa is smaller than that of R123 at the same heat flux. In conclusion, R245fa is a good candidate to replace ozone depleting R123 currently used in chillers from the view point heat transfer and environmental properties.

• Journal of Korea Game Society
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• v.15 no.3
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• pp.79-86
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• 2015

Effective feedback plays a key role in education environments to motivate the students and to maintain their flow. However, there usually lacks in providing effective feedbacks in education environments due to an excessive number of students and insufficient class times. The purpose of this paper is to analyze the educatees' response on game like feedback using App. In this paper, Class123 App developed and published by BravePops was used. During one semester, Class123 App had been used in engineering class and the educatees' responses on game like feedbacks using Class123 App are analyzed. Statistical analysis results show that the feedbacks using Class123 App made positive effects to motivate the students. Especially, the positive feedbacks were more effective than the negative feedbacks.

• Progress in Superconductivity
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• v.13 no.2
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• pp.133-138
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• 2011

To reduce the processing cost of the single grain REBCO (RE: Rare-earth elements) bulk superconductors, a cost-effective process should be developed. One possible way of developing the cost-effective process is the use of low-cost precursor powders. In this study, the single grain YBCO superconductors were fabricated using a home made powder. $YBa_2Cu_3O_{7-y}$ (Y123) powders were synthesized at $850-900^{\circ}C$ in air by the powder calcination method with repeated crushing and heat treatment steps. The processing parameters for the fabrication of single grain Y123 bulk superconductors, $T_{max}$ (maximum temperature), $T_p$ (peritectic temperature) and a cooling rate through $T_p$ were optimized. To enhance the flux pinning capacity of the single grain Y123 samples, $Y_2BaCuO_5$ (Y211) particles were dispersed in the Y123 matrix by adding $Y_2O_3$ powder to the calcined Y123 powder. Applying the optimized processing condition, the single grain Y123 superconductors with $T_c=91\;K$ and $J_c=1.5{\times}10^4\;A/cm^2$ at 2 T were successfully fabricated using a home made powder. The levitation forces and trapped magnetic field at 77 K measured using a Nd-B-Fe permanent magnet of 5300 G were 47 N and 3000 G, respectively, which are comparable to those obtained for the samples fabricated using a commercial grade Y123 powders.