• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.75-82
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• 2021

This study investigated the fire risk assessment of woods and plastics for construction materials, focusing on the fire performance index-III (FPI-III), fire growth index-III (FGI-III), and fire risk index-IV (FRI-IV) by a newly designed method. Japanese cedar, red pine, polymethylmethacrylate (PMMA), and polyvinyl chloride (PVC) were used as test pieces. Fire characteristics of the materials were investigated using a cone calorimeter (ISO 5660-1) equipment. The fire performance index-III measured after the combustion reaction was found to be 1.0 to 15.0 with respect to PMMA. Fire risk by fire performance index-III increased in the order of PVC, red pine, Japanese cedar, and PMMA. The fire growth index-III was found to be 0.5 to 3.3 based on PMMA. Fire risk by fire growth index-III increased in the order of PVC, PMMA, red pine, and Japanese cedar. COpeak concentrations of all specimens were measured between 106 and 570 ppm. In conclusion, it is understood that Japanese cedar with a low bulk density and PMMA containing a large amount of volatile organic substances have a low fire performance index-III and high fire growth index-III, and thus have high fire risk due to fire. This was consistent with the fire risk index-IV.

• Korean Journal of Radiology
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• v.21 no.12
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• pp.1285-1293
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• 2020

Objective: To evaluate the effects of vasodilators on contrast enhancement and transluminal attenuation gradient (TAG) of coronary arteries at coronary computed tomography angiography (CCTA). Materials and Methods: We retrospectively reviewed CCTA scans of patients who underwent double-acquisition CCTA; CCTA without a vasodilator, and CCTA during a intravenous (IV) infusion of nitrate. Among them, we enrolled 19 patients who had no significant atherosclerotic lesions or coronary spasms. In the control group, 28 patients were enrolled who showed normal coronary arteries on CCTA, which was acquired by a conventional method (sublingual vasodilator). We measured the TAG and Hounsfield units for each of the three major epicardial coronary arteries (reported as 'ProxHU') and then compared the results between the nitrate administration methods (CT without vasodilator [CT_pre], CT with IV vasodilator [CT_iv], and CT with sublingual vasodilator [CT_sub]). Results: The mean TAG showed a significant difference between the coronary arteries (right coronary artery [RCA] > left anterior descending artery [LAD] > left circumflex artery [LCX], p < 0.05), while there was no difference in ProxHU of each coronary artery in all three types of nitrate administration methods (p > 0.05). The TAG of CT_pre group showed steeper slope than those of vasodilator groups (CT_iv and CT_sub) on LAD and LCX ([LAD: CT_pre = -22.1 ± 6.66, CT_iv = -16.76 ± 5.78, and CT_sub = -16.47 ± 5.78, p = 0.005], [LCX: CT_pre = -31.26 ± 17.43, CT_iv = -23.74 ± 14.06, and CT_sub = -20.94 ± 12.15, p = 0.051]), while that of RCA showed no significant differences (p = 0.600). When comparing proxHU, CT_iv showed higher proxHU than that of CT_pre or CT_sub, especially on LCX (CT_pre = 426.7 ± 68.3, CT_iv = 467.9 ± 84.9, and CT_sub = 404.9 ± 63.3, p = 0.013). ProxHU showed a negative correlation with TAG on all three of methods (r = -0.280, p < 0.001). Conclusion: TAG in CCTA was significantly affected by vasodilator administration. Both TAG and ProxHU of coronary arteries tend to increase with vasodilator administration on CCTA.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.10
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• pp.1155-1162
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• 2004

This paper is the forth paper of several companion papers which compare the method of Air-Fuel ratio determination. In the previous work, various AFR calculations were performed for various fuels and the results were compared with each other. The comparison, however, were limited to numerical value and estimation of each equation or method was insufficient. In this paper, the overall estimation of the methods was attempted. Also, the method of trouble shooting of instrumentation was presented. Through the estimation of methods, it is concluded that the Eltinge method contains inherently the most perfect thermal dissociation model as far as the exhaust composition is concerned; therefore, this might be regarded as the most general equation of AFR determination among the existing ones. The others might be considered as approximate form. In addition, the mal-distribution factor in Eltinge method is qualitatively equivalent to thermal dissociation chemical equilibrium constant K. Lastly, it is illustrated that all instrumentation error, including the sampling line leakage, can be easily detected through the analyzing the exhaust component on the Eltinge chart.

• Structural Engineering and Mechanics
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• v.46 no.2
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• pp.179-196
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• 2013

An experimentally measured single footfall trace (SFT) from a walking subject needs to be extended into a continuous force curve, which can then be used as load for floor vibration serviceability assessment, or on which further analysis like discrete Fourier transform can be conducted. This paper investigates the accuracy, applicability and parametrical sensitivity of four extension methods, Methods I to IV, which extends the SFT into a continuous time history by the walking step rate, stride time, double support proportion and the double support time, respectively. Performance of the four methods was assessed by comparing their results with the experimentally obtained reference footfall traces in the time and frequency domain, and by comparing the vibrational response of a concrete slab subjected to the extended traces to that of reference traces. The effect of the extension parameter on each method was also explored through parametrical analysis. This study finds that, in general, Method I and II perform better than Method III and IV, and all of the four methods are sensitive to their extension parameter. When reliable information of walking rate or gait period is available in the test, Methods I or II is a better choice. Otherwise, Method III, with the suggested extension parameter of double support time proportion, is recommended.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.2
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• pp.112-117
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• 1989

This paper describes to the unit rectangle EB direct writing lithography method using SEM. This method has the constant exposure time to any rectangle pattern. In order to change the EB current according to various rectangle size for the constant exposure time, the supply current of condenser lens in controlled by BITMAP-IV CAD system. By this method, the resizing procedure of density pattern area is not needed to pattern data conversion, and the through-put ofr exposure is increased about 172 times compared with the unit scan exposure method.

• Knowledge Management Research
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• v.7 no.2
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• pp.69-96
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• 2006

The purpose of this study is to find success factors of knowledge management in Korean firms, confirm them empirically, and verify their relative importance in terms of company size and industry type. The major studies on the knowledge management were deliberately selected and interpretively analyzed to find the success factors of Korean firms. As a result of the analysis, five success factors(top management's will, evaluation reward, organizational culture, knowledge management system, organizational structure) have been found. The empirical researches to make certain whether the above five factors derived are actually true or not have been separately performed by using questionnaire method. Based on the data collected, it is found that all five factors are significant. The degree of relative importance among the success factors of knowledge management in Korean firms has been found as: (i)top management's will, (ii)organizational culture, (iii)evaluation-reward, (iv)knowledge management system, (v)organizational structure. In company size, large firm's degree of relative importance among the success factors are: (i)top management's will, (ii)organizational culture, (iii)evaluation-reward, (iv)knowledge management system, (v) organizational structure. And medium-small firm's degree of relative importance among the success factors of knowledge management in Korean firms has been found as: (i)top management's will, (ii)organizational culture, (iii) evaluation-reward, (iv)knowledge management system, (v)organizational structure. Finally, in type of industry, manufactural firm's degree of relative importance among the success factors of knowledge management in Korean firms has been found as: (i)top management's will, (ii)organizational culture, (iii)evaluation-reward, (iv)knowledge management system, (v)organizational structure. And non-manufactural firm's degree of relative importance among the success factors of knowledge management in Korean firms are: (i)top management's will, (ii)organizational culture, (iii)evaluation-reward, (iv)knowledge management system, (v)organizational structure.

• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.102-108
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• 2006

The IscA gene, encoding a levansucrase of 424 amino acids (aa) residues, was cloned from the genomic DNA of Pseudomonas aurantiaca S-4380, and overexpressed in Escherichia coli. The recombinant levansucrase overexpressed in E. coli was then used to produce levan from sucrose. Levan crystals with 98% purity could be obtained from the reaction mixture with $62\%$ yield using an alcohol precipitation method. The molecular weight of the levan was $7\times10^5$ daltons. Methylation studies showed that the levan was branched: main linkage C-2,6; branched linkage C-2,1; and degree of branching $6\%$. Three bacterial levans from different strains were incubated with levan fructotransferase (LFTase) from Arthrobacter ureafaciens K2032, which produced $di-\beta-D-fructofuranose$ dianhydride IV (DFA IV); final conversion yields from the levans to DFA IV were $39\%$ in Zymomonas mobilis, $53\%$ in Serratia levanicum, and $59\%$ in P. aurantiaca S-4380 levansucrase. The levan from P. aurantiaca S-4380 levansucrase gave the highest conversion yield of levan to DFAIV so far reported.

• The Korean Journal of Pain
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• v.21 no.3
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• pp.211-216
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• 2008

Background: Postoperative pain after bilateral total knee replacement (TKR) is expected to be more severe than unilateral TKR. Intravenous patient-controlled analgesia (IV PCA) is less effective than other methods of pain management especially immediately after an operation even though it is an easily controlled method for managing pain. This study was designed to evaluate the effect of femoral nerve blocks combined with IV PCA after bilateral TKR for postoperative pain control. Methods: The patients in group I (n = 20) were given only IV PCA with morphine and group II (n = 20) were given bilateral femoral nerve blocks with 12 ml of 0.25% bupivacaine and epinephrine 1 : 400,000 before extubation followed by an IV PCA. Main outcome measures included numerical rating pain score, cumulative opioid consumption, hourly dose during each time interval, and side effects. Results: The pain score in group II was significantly lower than that in group I immediately after recovery of awareness and at 3, 6, 12 hours postoperatively. Cumulative opioid consumption was significantly decreased in group II during the first 48 hours postoperatively. The hourly dose in group II was also significantly lower than that in group I until 12 hours postoperatively. There was no difference in side effects between the groups. Conclusions: We concluded that bilateral femoral nerve blocks improve analgesia and decrease morphine use during IV PCA after bilateral TKR.

• Journal of Chest Surgery
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• v.33 no.4
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• pp.301-305
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• 2000

Background: The surgical indications of stage IV non-small cell lung cancer(NSCLC) are extremely limited with its controversial results. We analyzed the surgical results and survival in selected patients with resectable stage IV NSCLC. Material and Method: We reviewed the medical records of 21 patients who underwent operation for stage IV NSCLC from Jan. 1992 to Sep. 1999. Result: The mean age of patients was 55.6 years(range: 35 to 78). Sixteen were men and 5 were women. Tissue types were squamous cell carcinoma in 10(45.5%), adenocarcinoma in 9(40.9%), large cell carcinoma in 1 and carcinosarcoma in 1. Distant metastatic lesions were ipsilateral other lobe of lung in 18, brain in 2 and adrenal gland in 1. Pneumonectomy was performed in 16 patients, bilobectomy in 3, and lobectomy in 2 who underwent previous operatin for brain metastasis. Mean follow-up duration was 21.2$\pm$17.7 months. During follow-up period, 13 patients died. Three-and 5-year survival of patients were 38.0% and 19.0%, the median survival time was 19.1$\pm$7.8 months. In the group with ipsilateral pulonary metastasis(PM, n=18), 3- and 5-year survival of patients with N0 and N1(n=9) disease were 64.8% and 32.4%, median survival time was 55.3$\pm$27.2 months. Three-year survival of patients with N2(n=9) disease was 11.1%, median survival time was 10.6$\pm$0.3 months. The survival of N0 and N1 disease group was significantly better than that of N2 disease group(p=0.042). Also the disease free survival of N0 and N1 was significantly better than that of N2 disease in overall group(53.3 months vs 12.1 months, p=0.036) and ipsilateral PM group(63.4 months vs 8.8 months, p=0.001). Conclusion: We suggest that surgical treatment is worthful modality in well selected patients with stage IV NHSCLC especially with ipsilateral PM and N0 or N1 disease,. Nevertheless our study indicate questions that will need to be experienced further in larger studies.

• The Korean Journal of Pain
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• v.35 no.3
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• pp.311-318
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• 2022

Background: Ketamine is widely used in infants and young children for procedural sedation and anesthesia. The aim of this study was to evaluate the efficacy and safety of low dose oral ketamine to control pain and distress in children during intravenous (IV) cannulation. Methods: This is a prospective, randomized, double-blind study, including children aged between 3 and 6 years requiring a non-emergent IV-line placement. Children were randomly assigned to two groups, treated either with oral ketamine or a placebo. All patients were monitored for vital signs. Pain was assessed using the Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) and Wong-Baker Faces Pain Rating Scale (WBFS) scales and sedation using a 5-point sedation score. The facility of IV-line placement was measured by a 3-point scale. Adverse effects were recorded after 1 and 24 hours. Results: A total of 79 and 81 children were entered in the ketamine and placebo groups, respectively. The heart and respiratory rates increased significantly in the placebo group. The median CHEOPS 4 (95% confidence interval [CI]: 3, 4, P < 0.001) and WBFS 6 (95% CI: 4, 6, P < 0.001) scores decreased statistically in the ketamine group. IV-line placement was 50% easier in the ketamine group (95% CI: 37%, 63%, P < 0.001). No serious adverse effects were observed in all cases. Conclusions: Low dose oral ketamine effectively decreased the pain and distress during IV cannulation in children without any significant adverse reactions.