• Journal of Nutrition and Health
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• v.41 no.4
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• pp.307-316
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• 2008

The purpose of the study was to investigate nutritional status of chronic obstructive pulmonary disease (COPD) patients and to find out the differences according to the stages of disease. From March to October, 2006, 41 stable male patients of mild to severe COPD patients were recruited from Seoul National University hospital. The patients' of body weight and fat free mass were assessed by bioelectrical impedance analysis. The nutritional status of the patients was also assessed by 3-day recall, index of nutritional quality (INQ), dietary diversity score (DDS), dietary variety score (DVS), food group index pattern and dietary quality index (DQI). The total of 41 patients were classified into three groups, stage I, stage II and stage III groups according to the classification of Global Initiative for Chronic Obstructive Lung Disease (GOLD) standard. The mean age of the patients in each stage were 67.2-66.9 years showing no significant difference. The ratio of $FEV_1$/FVC were $57.5{\pm}7.3$, $46.9{\pm}7.6$ and $38.2{\pm}6.8%$, respectively showing significant differences according to the stages of disease. The fat free mass of the stage II ($48.2{\pm}4.7kg$) and III ($47.3{\pm}4.5kg$) was significantly lower than that of stage I ($53.1{\pm}6.9kg$) patients. There were significant correlation of fat free mass with $FEV_{1}$, and BMI (body mass index) with $FEV_{1}$/FVC ratio (p < 0.05). COPD patients showed the diet-related clinical symptoms of anorexia, dyspnea, dyspepsia, and chewing difficulty. Daily intakes of calorie, K, vitamin $B_2$ and folate of the patients were very low ($83.8{\pm}20.7%$, $58.9{\pm}14.4%$, $70.7{\pm}19.6%$ and $74.4{\pm}10.2%$, respectively) however, they did not significantly different according to the stages of disease. Daily intake of calcium was significantly lower in the stage III patients (p < 0.05). The mean scores of dietary variety score was significantly lower in the stage III patients (p < 0.001). Dietary quality index of the patients were not different among the stages of disease and the scores indicated poor quality of diet. As a summary, we found that body fat free mass, regularity of exercise, frequency of having snacks and dietary variety score were significantly associated with the severity of chronic obstructive pulmonary disease.

• Journal of Ocean Engineering and Technology
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• v.30 no.4
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• pp.327-333
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• 2016

Reinforced concrete structures have found wide usage in land and maritime applications. However, the corrosion of reinforced concrete has been recognized as a serious problem from economic and safety standpoints. In previous studies, the corrosion behavior of the inner steel bar embedded in mortar (W/C: 0.4, 0.5) was investigated using electrochemical methods. In this study, multiple mortar test specimens (W/C: 0.6) with six different cover thicknesses were prepared and immersed in flowing seawater for five years. Subsequently, equations related to the cover thickness, period of immersion, and corrosion characteristics of the embedded steel bar were evaluated using electrochemical methods. Prior to immersion, the corrosion potentials indicated an increase with increasing cover thickness, and after five years, all corrosion potentials demonstrated a trend in the positive direction irrespective of the cover thickness. However, the relationships between the corrosion potential and cover thickness were not in complete agreement. Furthermore, after five years, all of the corrosion potentials indicated values that were nobler compared to those obtained prior to immersion, and their corrosion current densities also decreased compared to their values obtained prior to immersion. It was considered that the embedded steel bar was easily corroded because of the aggression of water, dissolved oxygen, and chloride ions; a higher W/C ratio also assisted the corrosion process. The corrosive products deposited on the surface of the steel bar for five years cast a resistance polarizing effect shifting the corrosion potential in the nobler direction. Consequently, it was considered that the W/C ratio of 0.6 showed nearly same results as those of W/C of 0.4 and 0.5. Therefore, the corrosion potential as well as various parameters such as the cover thickness, period of immersion, and W/C ratio must be considered at once for a more accurate evaluation of the corrosion property of reinforced steel exposed to marine environment for a long period.

• Journal of Ocean Engineering and Technology
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• v.30 no.4
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• pp.334-340
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• 2016

The combustion chamber of a diesel engine is often exposed to a more serious wear and corrosion environment than other parts of the engine because its temperature increases as a result of using heavy oil of low quality. Therefore, repair and built-up welding methods must be performed on worn or corroded parts of the piston crown, exhaust valve, etc. from an economical point of view. In this study, Inconel 718 filler metal was used in repair welding on the groove of a forged steel specimen for a piston crown, along with built-up welding on the surface of another forged steel specimen. Then, the corrosion characteristics of the weld metal zone for the repair welding and the deposited metal zone for the built-up welding were investigated using electrochemical methods in a 35% H₂SO₄ solution. The deposited metal zone indicated better corrosion resistance than the weld metal zone, showing a nobler corrosion potential, higher impedance, and smaller corrosion current density. It is considered that metal elements with good corrosion resistance were generally included in the filler metal, and these elements were also greatly involved in the deposited meta by built-up welding, whereas the weld metal consisted of metal elements mixed with both the filler metal and base metal elements because of the molten pool produced by the repair welding. Finally, it is considered that the hardness of the weld metal was increased by the repair welding, whereas the built-up welding improved the corrosion resistance of the deposited metal.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.5
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• pp.853-859
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• 2007

This paper presents a microstrip patch array antenna having transmission feed and reception feed for satellite communication in the Ku band. In this paper, the element of the patch array antenna is a three-stacked structure consisting of one radiation patch and two parasitic patches for high gain and wide bandwidth characteristics. To obtain higher gain, the unit elements are expanded into a $1{\times}8$ may using a mixture of series and parallel feeds. The proposed antenna has horizontal polarization for the Rx band and vertical polarization for the Tx band. To verify the practicality of this antenna, we fabricated a three-stacked patch array antenna and measured its performance. The gain of the array antenna in the Rx and Tx bands exceeds 17 and 18 dBi, respectively. The impedance bandwidth is over 10 % in both bands. The cross-polarization level is below -25 dB, and the sidelobe level is below -9.4 dB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.10
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• pp.1916-1923
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• 2007

We have studied to obtain the SAW filter for the passband was formed on the Langasite substrate and was evaporated by Aluminum-Copper alloy and thin we performed computer-simulated by simulator. We cm fabricate that the block weighted type IDT as an input transducer of the filter and the withdrawal weighted type IDT as an output transducer of the filter from the results of our computer-simulation. Also, we have performed to obtain the properly design conditions about phase shift of the SAW filter for WCDMA. We have employed that the number of pairs of the input and output IDT are 50 pairs and the thickness and the width of reflector are $5000\;{\AA}$ and $3.6{\mu}m$ respectively. And we have employed that the distances from the hot electrode to the reflector are $2.0{\mu}m$, $2.4{\mu}m$ and the distance from the hot electrode to the ground is $1.5{\mu}m$ respectively. Frequency response of the fabricated SAW filter has the property that the center frequency is about 190MHz and bandwidth at the 3dB is probably 7,8MHz. And we could obtain that return loss is less then -18dB, ripple characteristics is probably 3dB and triple transit echo is less then -25dB after when we have matched impedance.

• Bulletin of the Korean Chemical Society
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• v.21 no.11
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• pp.1125-1132
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• 2000

The pH effect of the precursor solution on the preparation of $LiCoO_2$ by a solution phase reaction containing malonic acid was carried out. Layered $LiCoO_2$ powders were obtained with the precursors prepared at the different pHs (4, 7, and 9) and heat-treated at $700^{\circ}C(LiCoO_2-700)$ or $850^{\circ}C(LiCoO_2-850)$ in air. pHs of the media for precursor synthesis affects the charge/discharge and electrochemical properties of the $LiCoO_2electrodes.$ Upon irrespective of pH of the precursor media, X-ray diffraction spectra recorded for $LiCoO_2-850$ powder showed higher peak intensity ratio of I(003)/I(104) than that of $LiCoO_2-700$, since the better crystallization of the former crystallized better. However, $LiCoO_2$ synthesized at pH 4 displayed an abnormal higher intensity ratio of I(003)/I(104) than those synthesized at pH 7 and 9. The surface morphology of the $LiCoO_2-850$ powders was rougher and more irregular than that of $LiCoO_2-700$ made from the precursor synthesized at pH 7 and 9. The $LiCoO_2electrodes$ prepared with the precursors synthesized at pH 7 and 9 showed a better electrochemical and charge/discharge characteristics. From the AC impedance spectroscopic experiments for the electrode made from the precursor prepared in pH 7, the chemical diffusivity of Li ions (DLi+) in $Li0.58CoO_2determined$ was 2.7 ${\times}$10-8 $cm^2s-1$. A cell composed of the $LiCoO_2-700$ cathode prepared in pH 7 with Lithium metal anode reveals an initial discharge specific capacity of 119.8 mAhg-1 at a current density of 10.0 mAg-1 between 3.5 V and 4.3 V. The full-cell composed with $LiCoO_2-700$ cathode prepared in pH 7 and the Mesocarbon Pitch-based Carbon Fiber (MPCF) anode separated by a Cellgard 2400 membrane showed a good cycleability. In addition, it was operated over 100 charge/discharge cycles and displayed an average reversible capacity of nearly 130 mAhg-1.

• Ceramist
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• v.21 no.4
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• pp.378-387
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• 2018

The optimal fabrication conditions for $Gd_{0.1}Ce_{0.9}O_{2-{\delta}}$(GDC) buffer layer and $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-{\delta}}$ (LSCF) cathode on 1mol% $CeO_2-10mol%\;Sc_2O_3$ stabilized $ZrO_2$ (CeScSZ) electrolyte were investigated for application of IT-SOFCs. GDC buffer layer was used in order to prevent undesired chemical reactions between LSCF and CeScSZ. These experiments were carried out with $5{\times}5cm^2$ anode supported unit cells to investigate the tendencies of electrochemical performance, Microstructure development and interface reaction between LSCF/GDC/CeScSZ along with the variations of GDC buffer layer thickness, sintering temperatures of GDC and LSCF were checked, respectively. Electrochemical performance was analyzed by DC current-voltage measurement and AC impedance spectroscopy. Microstructure and interface reaction were investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Although the interfacial reaction between these materials could not be perfectly inhibited, We found that the cell, in which $6{\mu}m$ GDC interlayer sintered at $1200^{\circ}C$ and LSCF sintered at $1000^{\circ}C$ were applied, showed good interfacial adhesions and effective suppression of Sr, thereby resulting in fairly good performance with power density of $0.71W/cm^2$ at $800^{\circ}C$ and 0.7V.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.4
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• pp.459-466
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• 2018

Hazardous and Noxious Substances (HNS) are defined as substances that are likely to create a significant impact on human health and marine ecosystem when they are released into the marine environment. Recently, as the volume of HNS transported by ships increases, the rate of leakage accidents also increases. Therefore, research should be conducted to control and monitor sunken materials from the viewpoint of technology development for hazardous material leakage accident response. In this paper, acoustic detection experiments were carried out using HNS substitute materials in order to confirm the possibility of acoustic detection of sunken HNS on the sediment. The castor oil, which has a similar acoustic impedance with chloroform, is used as a substitute. 200 kHz high frequency signals were used to discriminate the reflected signals and measure reflection loss from the interface between water and castor oil. The reflection loss measured is in good agreement with the modeling results, showing a possibility of acoustic detection for sunken HNS.

• Journal of Korean Medicine for Obesity Research
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• v.2 no.1
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• pp.37-42
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• 2002

Objectives: To compare the body composition of the postpartal female weight-gained over the recommended during pregnancy with that of normal female with same age. female diagnosed as obesity and postpartal female weight-gained within the recommended during pregnancy. Methods: From Apr. 1. 2001 to Feb. 28. 2002, there were 745 delivery in Dept. of Obstetrics & Gynecology, Kyung-Hee Medical Center. 32 mothers of them wanted to be investigated about the weight gain during their pregnancy. We excluded 12 persons who had gained within the recommended weight$(15{\beta}{\prod})$ and had diagnosed as the diseases inducing pathologic edema, preeclamsia. gestational heart or renal diseases, for example. In 2 days after delivery(nomal) or 5 days after(Caesarean section) we analysed the body composition of 20 persons. Results: 1. Compared with normal female, body weight, body mass index and body fat of the women gained over the recommended were increased and there made alternation to the increase of the percentage of body fat or the decrease of the percentage of lean body mass. 2. Compared with obese women who had same body mass index, the women gained over the recommended showed a little increase of body fluid, protein and mineral, but had a little decrease of the percentage of body fat. 3. The percentages of body fat increased with the women gained over the recommended, the women gained within the recommended and the obese women in order. This could imply the relation between the pregnancy, weight gain during pregnancy and the obesity. 4. The weights before pregnancy were same in the women gained over the recommended and the women gained within the recommended. But the weights just after delivery kept the gap happened during pregnancy between them and its main cause was the increase of body fat. Conclusions : The women gained over the recommended during pregnancy experienced the chage of body composition and its main cause was the increase of body fat. So compared with the women gained within the recommende, postpartal obesity more frequently could happen.

• Journal of Korean Medicine for Obesity Research
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• v.3 no.1
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• pp.7-16
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• 2003

Objectives : The lipolytic effects of catecholamines in adipose tissue are mediated by members of adrenergic receptors. This study was conducted to examine the effects of ${\beta}2-AR$ Gln27Glu (Q27E) polymorphism on obesity indices and risk among obesity clinic patients. Methods : 532 subjects, 38 men and 494 women, who attended a weight loss program in a local obesity clinic were analyzed. Height, weight, BMI, WHR and obesity index were measured or calculated. Body composition was measured by bio-impedance analysis. Genotype of ${\beta}2-AR$ polymorphism in codon 27 was analyzed by PCR-RFLP method. Serum concentrations of fasting glucose, total and HDL cholesterol, and triglyceride were determined by autobiochemical analyzer. Results: The Genotype distributions of ${\beta}2-AR$ gene were QQ type 81.3%, QE type 17.9% and EE type 8%. Therefore, the frequency of E allele of ${\beta}2-AR$ gene was 0.170 in the total subjects. The frequency of the ${\beta}2-AR$ variant genotype(QE+EE) was significantly higher in obese group($BMI{\geqq}25$) compared with non-obese group(p=0.027). Weight was significantly higher in variant(QE+EE) type compared with normal(QQ) type in total subjects(p=0.001), male(p=0.022) and female(p=0.013). BMI, obesity index and WHR were also significantly higher in QE+EE type. Body fat man was significantly higher in QE+EE type in total subjects(p=0.005) and female(p=0.027). When forward stepwise regression analysis was used to create a model of risk predictors of obesity($BMI{\geqq}25$), QE+EE type of ${\beta}2-AR$ gene was found to be a significant risk factor for obesity (p=0.042, ORs 1.597). Conclusions: QE+EE genotype of ${\beta}2-AR$ was associated with increased obesity indices and might be a significant risk factor for obesity.