• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.1
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• pp.1-8
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• 1999

In recent years, concern has been raised about the technique of controlling electrical breakdown by using laser in many fields. Especially, laser has attracted much attention in the Electro-Discharge Machining(EDM) because of its many rrents. 1berefore, this research has been perfonred to obtain fundarrental data for the discharge guide technology by a pulsed Nd:YAG laser which can be awJied to discharge processing machining. 1be experilnnts of laser-guided de discharge have been carried out at low air pressure ranging from 0.2 to 20 torr. The minimum laser-guided de discharge voltage $V_{G.min}$ at the given pressures P and distances d between an anode and a cathode was rreasured It is found that $V_{G.min}$ is much lower than the natural discharge voltage $V_{ND}$, and the values of VGrrin and $V_{ND}$ as a function of P.d has a similar tendency. The laser output energy $E_{out}$ decreases with input pulse duration $t_p$ increasing, and the rrore the value of $t_p$ increases, the higher that of V$V_{G.min}$ is obtained because the number of photons N decreases with $t_p$ increasing. In addition, the laser-guided de discharge range and the discharge guide characteristics as laser outpIt $E_{out}$ was investigated.igated.

• Korean Journal of Community Nutrition
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• v.22 no.5
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• pp.441-455
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• 2017

Objectives: The purpose of this study is to describe beverage patterns among healthy Korean adults and investigate their association with prevalence and components of metabolic syndrome. Methods: Subjects consisted of 6,927 Korean adults, aged 19-64 years in the $6^{th}$ Korea National Health and Nutrition Examination Survey (KNHANES, 2013-2015). Beverages were regrouped into twelve groups based on food codes and beverage intake (g/day) was assessed by 24-hour recall. Factor analysis was used to obtain beverage patterns. Waist circumference and body mass index (BMI) were used as anthropometric data; fasting blood glucose, triglyceride, high density lipoprotein (HDL), and blood pressure were used as biochemical indicators. The odds ratio (OR) for prevalence of metabolic syndrome and components of metabolic syndrome was assessed using logistic regression analysis. Results: Three beverage patterns were identified using factor analysis: 1) carbonated soft drinks 2) coffee (without added sugar or powdered creamer), and 3) alcoholic beverages. Subjects with high scores for the carbonated soft drink and coffee without added sugar or powdered creamer patterns were younger and subjects with high scores for the alcoholic beverage pattern were older. There were significant differences in gender distribution in all three beverage patterns, with men more likely to have high scores for carbonated soft drink and alcoholic beverage patterns. On the other hand, women were more likely to have higher scores for coffee without added sugar or powdered creamer pattern. Within each pattern, there were significant differences in sociodemographic and lifestyle characteristics such as education, household income, frequency of eating out, and smoking status according to the quartile of pattern scores. Alcoholic beverages and carbonated soft drinks patterns were associated with an increased levels of metabolic syndrome components, but coffee without added sugar or powdered creamer was not associated with any of metabolic syndrome components in healthy Korean adults after adjusting for age, sex, education, BMI, weight management, household income, smoking status, frequency of eating out, and energy intake. Conclusions: Alcoholic beverages and carbonated soft drinks patterns are associated with increased levels of metabolic syndrome components while coffee without added sugar or powdered creamer pattern is not associated with any of metabolic syndrome components in healthy Korean adults.

• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.4 s.19
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• pp.49-57
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• 2005

The purpose of this study is to closely examine the influence of the surcharge load applied to the retaining wall through some model tests, in which wall stiffness in each stage of excavation, horizontal displacement of the retaining wall and surface displacement of the backfill according to wall stiffness and ground conditions, and change and distribution of the earth pressure applied to it were measured and their values were produced, then these values were mutually compared with their theoretical values and their values after analysis of the data obtained at the field, and they were analytically studied, in order to closely examine the influence of the surcharge load applied to the retaining wall. Findings from this study are as follows: The shape of ground surface settlement curve on the model ground under surcharge load, different from the distribution curve of regular probabilities which is of a shape of ground surface settlement under no surcharge load, appears in that settlement in an arching shape shows where the center part of surcharge load shows the maximum settlement. In examining the maximum horizontal displacement with the surcharge load applied to each stage of excavation, it occured at the point of 0.8H(excavation depth) when finally excavated. Regarding the range in which the displacement of the retaining wall increases according to application of surcharge load, the increment of displacement showed till the point of depth which is of two times of the distance of load from the upper part of the wall. Also since each displacement of the foundation plate caused by the ground surface settlement according to each stage of excavation occured most significantly at the final stage. Also since regarding wall stiffness, the wall of its thickness of 4mm(flexible coefficient $p:480m^3/t$), produced maximum 3 times of wall stiffness than its thickness of 9mm(flexible coefficient $p: 40m^3/t$), it was found out that influence of wall stiffness is so significant.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.346-353
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• 2016

In the design conditions of some research reactors, the siphon phenomenon can cause continuous efflux of water during pipe rupture. A siphon breaker is a safety device that can prevent water efflux effectively. However, the analysis of the siphon breaking is complicated because many variables must be included in the calculation process. For this reason, a simulation program was developed with a user-friendly GUI to analyze the siphon breaking easily. The program was developed by MFC programming using Visual Studio 2012 in Windows 8. After saving the input parameters from a user, the program proceeds with three steps of calculation using fluid mechanics formulas. Bernoulli's equation is used to calculate the velocity, quantity, water level, undershooting, pressure, loss coefficient, and factors related to the two-phase flow. The Chisholm model is used to predict the results from a real-scale experiment. The simulation results are shown in a graph, through which a user can examine the total breaking situation. It is also possible to save all of the resulting data. The program allows a user to easily confirm the status of the siphon breaking and would be helpful in the design of siphon breakers.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.68-75
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• 2018

In this study, to solve the problems of the conventional crack repair and injection method, high elasticity latex was used as the material of the storage tube to withstand the high pressure in the center part differently from the general port. When the repair solution was injected into the crack part, The TPS method was developed so that the air existing in the TPS can be discharged. In addition, a new infusion port in which a valve blocking the backflow of the remediation solution was installed at the injection port was developed and the physical characteristics of the port were analyzed. As a result of the evaluation, it was found that the filling rate of the remedial solution was improved compared to the existing ordinary injector method, and the cracks were completely filled in the test conditions. Compressive strength and tensile strength after repair showed about 20% decrease after repair in case of using ordinary injector method, while TPS method showed about 2~7% increase after repair. The results of this study showed that the injection port method using the elastic storage tube increased the injection performance and the quality after repair compared to the conventional injector method. The result of this study is expected to be utilized as the basic data for application and commercialization of the result to the practical structure.

• Korean Journal of Applied Biomechanics
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• v.24 no.2
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• pp.151-160
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• 2014

The purpose of this study was to investigate the GRF(ground reaction force) parameters according to the shoes's heel heights and ground landing distances during downward stairs on bus. Participants selected as subject were consisted of young and healthy women(n=9, mean age: $21.30{\pm}0.48$ yrs, mean height: $164.00{\pm}3.05cm$, mean body mass: $55.04{\pm}4.41kg$, mean BMI: $20.47{\pm}1.76kg/m^2$, mean foot length: $238.00{\pm}5.37mm$). They were divided into 2-types of shoe's heel heights(0 cm/bare foot, 9 cm) and also were divides into downward stairs with 3 types of landing distance(20 cm, 35 cm, 50 cm). A one force-plate was used to collect the GRF(AMTI, USA) data from the sampling rate of 1000 Hz. The GRF parameters analyzed were consisted of the medial-lateral GRF, anterior-posterior GRF, vertical GRF, loading rate, Center of Pressure(${\Delta}COPx$, ${\Delta}COPy$, COP area) and Dynamic Postural Stability Index(MLSI, APSI, VSI, DPSI) during downward stairs on bus. Medial-lateral GRF and vertical GRF didn't show significant differences statistically according to the shoe's heel heights and landing distance, but 9 cm shoes heel showed higher vertical GRF than that of 0 cm bare foot in landing distance of 50 cm. Also anterior-posterior GRF didn't show significant difference statistically according to the shoe's heel heights, but landing distance of 20 cm showed higher than that of landing distances of 35 cm and 50 cm in anterior-posterior GRF. Loading rate didn't show significant difference statistically according to the landing distance, but 9 cm shoe's heel showed higher than that of 0 cm bare foot during downward stairs. The ${\Delta}COPy$ and COP area didn't show significant differences statistically according to the shoe's heel heights and landing distance, but 0 cm bare foot showed higher than that of 9 cm shoe's heel in ${\Delta}COPx$. Dynamic Postural Stability Index(MLSI, APSI, VSI, DPSI) didn't show significant differences statistically according to the landing distance, but 9 cm shoe's heel showed decreased value than that of 0 cm bare foot in dynamics balance. Considering the above, parameters of GRF showed different characteristics according to the shoe's heel heights and ground landing distances during downward stairs on bus.

• Journal of the Korean Vacuum Society
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• v.15 no.6
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• pp.581-586
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• 2006

We have generated the argon plasma in the diode chamber based on the established coaxial electrode type and investigated the emitted visible light for emission spectroscopy. We applied various voltages $2\sim3.5kV$ to the device by 0.5kV, and obtained the emission spectrum data for the focused plasma in the diode chamber on the argon pressure of 330 mTorr. The Ar I and Ar II emission line are observed. The electron temperature and ion density have been measured by the Boltzmann plot and Saha equation from assumption of local thermodynamic equilibrium (LTE) The Ar I and Ar II ion densities have been calculated to be $\sim10^{15}/cc\;and\;~10^{13}/cc$, respectively, from Saha equation.

• Journal of Trauma and Injury
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• v.21 no.1
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• pp.46-52
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• 2008

Purpose: This study was to evaluate the effect of arterial embolization on survival in patients with pelvic bone fractures and arterial bleeding. Methods: From January 2001 to December 2007, in all, 18 patients with pelvic bone fractures that had been treated with interventional arterial embolization were included in this retrospective study. The Injury Severity Score (ISS), the Revised Trauma Score (RTS), the initial hemodynamic status, the blood gas analysis, blood transfusion data, and mortality were the main outcome measurements. Results: Pelvic bone fractures were classified into lateral compression (LC), antero-posterior compression (APC), vertical shear (VS), and combined (CM) type according to the Young-Burgess classification. The Survivor group included 11 patients (61.1%), and the non-survivor group included 7 patients (38.9%). The mean ages for the survivor and the non-survivor groups were 40.0 and 45.6 years (p=0.517). The types of pelvic bone fractures were LC 11 (61.1%), APC 6 (33.3%), and VS 1 (5.6%): LC 7 (63.6%), and APC 4 (36.4%) in the survivor group and LC 4 (57.1%), APC 2 (28.6%), and VS 1 (14.3%) in the non-survivor group. The internal iliac artery was the predominant injured vessel among both the survivors (n = 5, 45.5%) and the non-survivors (n = 4, 57.1%). No differences in initial blood pressures, ISS, and RTS existed between the two groups, but the arterial pH was lower in the non-survivor group (pH 7.09 (${\pm}0.20$) vs 7.30 (${\pm}0.08$), p=0.018). The number of transfused 24-hour units of packed RBC was greater in the non-survivor group ($24.1{\pm}12.5$ vs $14.4{\pm}6.8$, p=0.046). Conclusion: No differences in initial blood pressure and trauma scores existed between survivors and non-survivors with pelvic bone fractures, who had been treated with arterial embolization, but arterial pH was lower the in non-survivors.

• Journal of Preventive Medicine and Public Health
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• v.22 no.3 s.27
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• pp.355-367
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• 1989

This study examined the physical and mental health factors affecting the industrial accidents of 142 injured and 1,212 uninjured workers in the shipbuilding industry from 1986 to 1988. The results acquired from the Todai Health Index (THI) and from analysis of the health examination were as follows: 1. Among the personal characteristics of the workers, the educational level of injured workers was significantly lower than that of the uninjured workers. 2. Among the physical characteristics, vision and $R\ddot{o}hrer$ Index of the injured workers were lower than those of the uninjured workers, and the difference was statistically significant. On the other hand, the differences in height, weight, hearing function, hematocrit, blood pressure, urine test, and X-ray findings were not statistically significant between the injured and uninjured workers. 3. The score of the THI questionnaire on the physical and mental health of the injured workers was higher than that of the uninjured workers, and the difference was statistically significant. 4. Form the THI score, the industrial workers had complained more about mental health than physical health and there was a statistically singinficant relation with the industrial accidents. 5. The relative risk expressed in terms of the odds ratio was 2.9 for poorer vision, 2.7 for a lower educational level, 2.2 for a higher THI score and 1.6 for overdrinking. 6 Educational level, vision, and the THI score were selected as significant factors influencing industrial accidents based on a log-linear model. According to the results of this model by logistic analysis, the odds ratio of industrial accidents was 1.8 for a lower educational level, 1.7 for poorer vision, and 1.6 for a higher THI score. 7 By event history analysis with the dependent variable as the duration of work at the time of the industrial accident, educational level, age, $R\ddot{o}hrer$ Index and THI score were the statistically significant variables selected, and the hazard rate of industrial accident occurrence was 0.24 for a lower educational level, 0.92 for age, 0.99 for a lower $R\ddot{o}hrer$ Index and 2.72 for a higher THI score. As we have seen, educational level and THI score were the most significant factors affecting the hazard rate of industrial accidents. Vision, $R\ddot{o}hrer$ Index, age, and drinking behavior were also statistically significant variables influencing industrial accidents. Therefore, in order to prevent industrial accidents, it is necessary to establish a health management plan for industry which can objectively evaluate not only the physical but also the mental health of the workers. If we use this type of study as a prospective study design, we can determine the relative risk of physical and mental health factors on industrial accidents. Furthermore, it is expected that this type of study will provide workers at high risk with more precise basic data for a health managment plan for industrial accident prevention.

• Korean Journal of Acupuncture
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• v.22 no.1
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• pp.7-21
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• 2005

Objectives : In the present study, the effect of electroacupuncture (EA) applied to SI6 and won-rak point on the ankle sprain model was examined. A common source of persistent pain in humans is the lateral ankle sprain. Methods : To model this condition, the rat's right ankle was bent repeatedly, overextending lateral ligaments, for 4 min under enflurane anesthesia. The rat subsequently showed swelling of the ankle and a reduced stepping force of the affected limb for the next several days. The reduced stepping force of the limb was presumably due to a painful ankle. EA was applied to the several acupuncture point on the contralateral forelimb for 30 min under gaseous anesthesia. After the termination of EA, behavioral tests measuring stepping force and Paw volume were Periodically conducted during the next 4 h and 18 h respectively. Results : EA applied to $SI_6$ with won-rak point produced more powerful improvement of stepping force of the sprained foot than to $SI_6$ alone lasting for at least 4 h. However, neigher $KI_4$ point nor $BL_{64}$ point produced any significant increase of weight bearing force. The improvement of stepping pressure was interpreted as an analgesic effect. The analgesic effect was specific to the acupuncture point since the analgesic effort on the ankle sprain pain model could not be mimicked by EA applied to $KI_4$ or $BL_{64}$. In addition, EA applied to $SI_6$ with won-rak combination point showed inhibitory effect on the paw edema induced by ankle sprain. Also, COX-2 protein expression increased by ankle sprain were suppressed by the EA stimulation. Conclusion : These data suggest that EA with won-rak combination point produces a more potent analgesic effect on the ankle sprain pain model in the rat and that EA with won-rak combination point induced anti-inflammatory effect through the suppression of COX-2 protein expression.