• Journal of the Korean Society of Industry Convergence
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• v.20 no.2
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• pp.115-124
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• 2017

This paper aims to develop an SMPS topology for handling a high range of input voltages based on a DC-DC flyback converter circuit. For this purpose, 2 capacitors of the same specifications were serially connected on the input terminal side, with a flyback converter of the same circuit configuration serially connected to each of them, so as to achieve high input voltage and an effect of dividing input voltage. The serially connected flyback converters have the transformer turn ratio of 1:1, so that each coil is used for the winding of a single transformer, which is a characteristic of doubly-fed configuration and enables the correction of input capacitor voltage imbalance. In addition, a pulse transformer was designed and fabricated in a way that can achieve the isolation and noise robustness of the PWM output signal of the PWM controller that applies gate voltage to individual flyback converter switches. PSIM simulation was carried out to verify such a structure and confirm its feasibility, and a 100W class stack was fabricated and used to verify the feasibility of the proposed high voltage SMPS topology.

• Journal of the Korean Society for Heat Treatment
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• v.33 no.6
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• pp.303-309
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• 2020

A vehicle's differential gear is a device designed to allow the vehicle's outer wheels to turn faster than the inner wheels when turning on a curve. The differential gear case is the main component of the differential gear system, which is composed of ring gear, pinion gear and side gear, and is fastened by pinion shaft pins. The differential gear case rotates when the vehicle is running, so balancing calibration is very important. In this study, a balancing machine that can diagnose and correct the differential gear case and mass imbalance of various rotating bodies was designed. The differential gear case was rotated at high speed to accurately diagnose the location and value of the unbalanced mass, and it was designed to be balanced and corrected by removing the unbalanced mass by drilling. After calibration, it was confirmed that the unbalanced value of all the measured samples was reduced to less than 180g.mm, and the unbalance reduction ratio was improved to 60~70%.

• Journal of Obesity & Metabolic Syndrome
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• v.27 no.4
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• pp.254-261
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• 2018

Background: The most beneficial dietary pattern in managing metabolic syndrome (MetS) in the elderly has not been ascertained. The aim of this study is to classify dietary patterns and to examine associations between dietary pattern, MetS and body composition in elderly Koreans. Methods: This study was conducted among Koreans 65 years or older using data from the Korea National Health and Nutrition Examination Survey in 2009. A total of 1,567 study subjects were included. All statistical analyses were conducted using SPSS version 20.0 and dietary patterns were classified by cluster analysis. Results: There were three dietary patterns derived by cluster analysis in this study. We observed that most South Korean elderly still maintain a traditional dietary pattern. Dietary patterns were classified as balanced (31%), imbalanced (40%), or very imbalanced (30%), with the majority of subjects having an unbalanced diet pattern in which their total energy and nutrient intake was insufficient compared with the Dietary Reference Intake for Koreans. Those in the very imbalanced group had a ratio of macronutrients (carbohydrates:fats:protein) of 81.15:7.18:11.50 and a 54% higher likelihood of having hypertriglyceridemia (P=0.025) compared with those in the balanced group. Conclusion: The current findings indicate that the diets of South Korean elderly are nutritionally imbalanced, including high carbohydrate consumption, which confers a high risk hypertriglyceridemia. These findings highlight the effect of nutritional imbalance in elderly with MetS.

• The Korean Journal of Pain
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• v.34 no.3
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• pp.332-338
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• 2021

Background: Trigeminal neuralgia (TN) is one of the most painful disorder in the orofacial region, and many patients have suffered from this disease. For the effective management of TN, fundamental epidemiologic data related to the target population group are essential. Thus, this study was performed to clarify the epidemiological characteristics of TN in the Korean population. This is the first national study to investigate the prevalence of TN in Korean patients. Methods: From 2014 to 2018, population-based medical data for 51,276,314 subscribers to the National Health Insurance Service of Korea were used for this study. Results: The incidence of TN was 100.21 per 100,000 person-years in the year of 2018 in Korea, and the male to female ratio was 1:2.14. The age group of 51-59 years had the highest prevalence of TN. Constant increases in medical cost, regional imbalance, and differences in prescription patterns by the medical specialties were showed in the management of TN. Conclusions: The results in this study will not only help to study the characteristics of TN, but also serve as an important basis for the effective management of TN in Korea.

• The Korean Journal of Food & Health Convergence
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• v.8 no.2
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• pp.15-27
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• 2022

This study aims to analyze the relative importance of bone age and chronological age in physique according to gender and to identify the relative importance of bone age, chronological age, and physique in physical fitness and motor coordination according to gender in order to alleviate the imbalance between physique and physical fitness in children. A total of 666 children(346 males, 320 females) between the ages of 11-14 were enrolled as subjects, and the skeletal maturation The skeletal maturation were measured by taking hand-wrist. Physical fitness were measured through a total of 4 components: muscular strength. The results of this study. First, physique variables for both males and females aged 11-14 were found to be more significant predictors of bone age than chronological age. Second, for physical fitness in males, in the order of %fat, body water, waist-hip ratio, weight, fat-free mass, and chronological age were more significant predictor variables; and in females, in the order of %fat, fat-free mass, height, chronological age, weight, bone age, fat mass, and body water were more significant predictor variables. For bone age and chronological age in physical fitness, bone age in males and chronological age in females found to be the more representative variables respectively.

• Physical Therapy Korea
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• v.15 no.4
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• pp.43-49
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• 2008

The objective of this study was to compare the differences on the activity and power of the wrist flexors and extensors in subjects before the use of a wrist extension splint, after nighttime wearing of the splint, and after daytime wearing of the splint. Ten healthy male and ten healthy female students (mean: $22.4{\pm}1.2$ years old) volunteered to wear custom-made wrist splints either during the night or during the day, The hand force of the wrist flexor and extensor, and grip force were measured by PowerTrack II and Dynatron, respectively. At the same time, the activities of the wrist flexor and extensor were recorded by' surface electromyography. The maximal hand force and motor unit recruitment of the flexor carpi ulnatis (FCU) increased significantly (p<.05) when tile subjects wore the wrist splints during the daytime, but the maximal hand power of the FCU decreased with nighttime use of the splints. The maximal hand power and motor unit recruitment of the extensor carpi radialis (ECR) and the ECR/FCU ratio decreased both during nighttime and daytime use. The decrement of the ECR/FCU ratio was significant (p<.05). Wearing a wrist extension splint during nighttime led to the maintenance of a lengthened position of the wrist flexor, resulting in the wrist flexor becoming weak. Wearing a wrist extension splint during the day induced the wrist flexors to be greater. In healthy people, the imbalance between the wrist flexors and extensors may be caused by the use of a wrist extension splint. This study indicates that therapists have to consider whether a splint will be effective, as well as the wearing time, when prescribing splints to people with problems of the musculoskeletal system.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.3
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• pp.184-191
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• 2004

Forest soils were collected from various sites adjacent to the heavy industrial complexes and soil solutions were extracted to characterize the chemical properties and to find factors affecting forest decline by acid deposition. Concentrations of $NO_3{^-}$, $SO{_4}^{2-}$, $F^-$ and Al in the soil solutions collected from industrial complexes were 2-33 times higher than those from the non-industrial areas. pH and Al concentrations were significantly correlated with $NO_3{^-}$ and $SO{_4}^{2-}$ concentrations. Forest soils from Onsan and Ulsan regions had very low Ca and Mg concentrations in the soil solutions. In these sites, the molar ratios of Ca/Al and Mg/Al were also lower than 2 and 1, respectively. Aluminum concentrations in the A and B horizons were 547 and $683mg\;kg^{-1}$, respectively, which were considered to be high enough to inhibit tree growth. Magnesium deficiency in A horizon and high concentrations of Al and Mn in B horizon were considered as the major limiting factors for tree growth by inhibiting the uptake of Ca and Mg and causing the imbalance of nutrients in both soil solution and trees.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.4
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• pp.679-686
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• 2004

In order to find the relationships of nutrient intakes and food consumptions to calorie intake for young and middle-aged men, a study was peformed using the data of Korean National HealthㆍNutrition Survey in 1998. Data from 659 young men (20 to 29 years) and 1,697 middle-aged men (30 to 49 years) were analysed for percent of recommended daily allowance (%RDA), index of nutritional quality (INQ) and nutrient adequacy ratio (NAR) in order to evaluate one's Quality and quantity. We found that energy and nutrient intakes were not significantly different between young and middle-aged groups. Their calorie and nutrient intakes were below their RDA. The most insufficiently consumed nutrient (less than 75% of RDA) was calcium followed by thiamin vitamin A, and calorie. The lacks of calorie, protein, iron, vitamin C, and niacin were more widely-spread in the twenties than the middle-aged. The mean nutrient adequacy ratio of the middle-aged was better than that of the young, even though some INQ were worse. Only for the subjects consumed sufficient energy, there were positive relations between grains, meats or alcoholic drinks to calorie level in middle-aged men but there were positive relations between broiled fish/shell or fats/oils to calorie level in young men. It seemed that both middle-aged men eating alcoholic drinks, broiled meat, and grains and young men eating cake/cookies, rice cake/potato cake, grains, and sugars could consume enough calorie with nutritional imbalance.

• Advances in pediatric surgery
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• v.3 no.2
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• pp.117-125
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• 1997

Seventy neonates with congenital intestinal atresia and stenosis who were treated at pediatric surgical service. Hanyang University Hospital from September 1979 to December 1996 were analyzed retrospectively. The lesion occurred in 27 cases at the duodenum, in 26 cases at the jeiunum, in 13 cases at the ileum and in 2 cases at the pylorus and colon each. There were 10 multiple atresias and 7 apple-peel anomaly cases. The atresia predominated over the stenosis by the ratio of 4 : 1. Male to female ratio was 1.3 : 1. The average gestational age was 38 weeks, and the average birth weight was 2,754 grams. Though 22.9 % were borne prematurely and 34.3 % had low birth weight, 92.3 % of them had a weight appropriate for gestational age. Polyhydramnios(40 %) was more frequently observed in duodenal and jeiunal atresia while microcolon in ileal atresia(58.3 %). Weight loss and electrolyte imbalance occurred more frequently in the duodenal stenosis cases because of delayed diagnosis. Twenty(55.6 %) of 37 jeiunoileal atresia cases had evidence of intrauterine vascular accident : 4 intrauterine intussusception, 3 intrauterine volvulus and 3 strangulated intestine in gastroschisis, and 10 cases of intrauterine peritonitis. There were one or more associated anomalies in 45 patients (64.3 %). Preoperatively proximal loop volvulus developed in 3 cases and proximal loop perforation in 5 cases and one case each of distal loop perforation, duodenal perforation and midgut volvulus occurred in the jeiunoileal atresia. Overall mortality rate was 20 %.

• Horticultural Science & Technology
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• v.31 no.4
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• pp.423-428
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• 2013

Although closed soilless culture is useful for saving water and fertilizers with minimizing environmental pollution, adequate management of nutrient solutions is still not stabilized in greenhouse cultivation. In order to investigate the problems occurred in closed soilless culture of Paprika (Capsicum annuum L., cv. Fiesta), we compared ion balance, fruit yield, and the water and fertilizer use efficiencies in the closed system with those in the open system. The plants were grown in rockwool culture with a nutrient solution of EC $2.5dS{\cdot}m^{-1}$. After 4 weeks of treatment, individual ratio of $NO{_3}^-$, $K^+$, $Ca^{2+}$, and $Mg^{2+}$ to total ion concentrations ($meq{\cdot}L^{-1}$) decreased from the initial value, especially the biggest decrement was observed in $K^+$, and on the other hand, $SO{_4}^{2-}$, $Cl^-$, and $Na^+$ were accumulated in the closed system. Yields after four-time harvests were 19% higher in the open system than in the closed system. Total volume of water used per unit area ($m^2$) in the open system was 20% higher, but the total water use per fruit was not significantly different between the two systems, while t total fertilizer use per fruit was 78% higher in the closed system. Amount of marketable fruits was not significantly different between the two systems. We concluded that the increase in $K^+$ supply and the replenishment of recycled nutrient solution every four weeks were required for preventing the imbalance or depletion of nutrients in the close soilless culture of paprika plants to get more balanced nutrient composition during whole cultivation period.