• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.329.2-329.2
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• 2014

지난 수년간 태양전지의 광전변환효율을 높이기 위해 자가 조립된 InAs 또는 GaSb와 같은 양자점을 GaAs 단일 p-n 접합에 적용하는 연구를 개발해 왔다. 그러나 양자점의 흡수 단면적에 의한 광 흡수도는 양자점층을 수십 층을 쌓으면 증가하지만 활성층에 결함을 생성시킨다. 생성된 결함은 운반자트랩으로 작용하여 태양전지의 광전변환효율을 감소시킨다. 본 실험에서는 양자점이 적용된 태양전지와 적용되지 않은 태양전지의 광전변환 효율을 비교하고, 깊은준위 과도용량 분광법을 이용하여 결함상태를 측정 및 비교함으로써, 활성층 내부에 생성된 결함이 광전변환 효율에 미치는 영향을 분석하였다. 소자구조는 분자선 증착 방법을 이용하여, 먼저 n+-형 GaAs기판위에 n+-형 GaAs를 250 nm 증착한 후, 도핑이 되지 않은 GaAs활성층을 $1{\mu}m$ 두께로 증착하였다. 마지막으로 n+ 와 p+-형 GaAs를 각각 50, 750 nm 증착함으로써 p-i-n구조를형성하였다. 여기서, n+-형 GaAs 과 p+-형 GaAs의 도핑농도는 동일하게 $5{\times}1018cm-3$로 하였다. 또한 양자점을 태양전지 활성층에 20층을 형성하였다. 이때 p-i-n 태양전지 와 양자점 태양전지의 광전변환 효율은 각각 5.54, 4.22 % 를 나타내었다. p-i-n 태양전지의 개방 전압과 단락전류는 847 mV, 8,81 mA이며 양자점 태양전지는 847 mV, 6.62mA로 확인되었다. 태양전지의 전기적 특성을 측정하기 위해 소자구조 위에 Au(300nm)/Pt(30nm)/Ti(30nm)의 전극을 전자빔증착장치로 증착하였으며, 메사에칭으로 직경 $300{\mu}m$의 태양전지 구조를 제작하였다. 정전용량-전압 특성 및 깊은준위 과도용량 분광법을 이용하여 태양전지의 결함분석 및 이에 따른 광전변환 특성인자와의 상관관계를 논의할 것이다.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.257-260
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• 2008

This study will make P-M interaction diagram of residual capacity at fire-damaged High strength concrete column with polypropylene fiber. Evaluating capacity of column decreasing spalling with P-M interaction diagram is important. because high strength concrete column with polypropylene fiber isn't section area loss. P-M interaction diagram that is made to analyze according to a various parameters is useful index for design and evaluating capacity of columns. In this study, spalling, temperature distribution of interior column, residual strength and movement of column in eccentric loading are studied with expose time of high temperature. For study fire test that is similar real act, and after cooling in normal condition residual strength of specimen is estimated. And this study use DIANA(Displacement Analyzer) for analyzing nonlinear analysis. with experiment temperature and strength data.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.6
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• pp.384-390
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• 2003

Removal of phosphate from soil by leaching, runoff, and plant uptake is strongly influenced by the content and absorption characteristics of P in soil. In this study the relationships between water soluble phosphate and phosphate retention capacity of the soil was investigated. Water soluble and available phosphate, and phosphate absorption characteristics of 35 paddy soils were measured during incubation at $25^{\circ}C$. Water soluble phosphate content was highly correlated with available phosphate content, phosphorus absorption capacity (PAC), and phosphate absorbed (PS) in air-dried and wet soils. The most significant relationship was found between water soluble phosphate and the ratio of available phosphate and phosphate sorbed, and the relationship $0.01M\;CaCl_2-P=0.0828$ (Av. $P_2O_5/PS$)+0.0374 could be suggested for the estimation of water soluble phosphate from soil phosphorus characteristics.

• Journal of the Korean Chemical Society
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• v.36 no.4
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• pp.552-557
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• 1992

Chloramphenicol was studied by differential pulse polarography (DDP). A reduction peak which is dependent on pH of the solution appeared in the voltage range between zero and -1.50 volt vs. Ag/AgCl (sat. KCl) reference electrode. A plot of peak potentials (Ep) measured at room temperature (20$^{\circ}C$) vs. pH of the chloramphenicol solutions showed linear relationship changing slope (Ep/pH) at pH 8.9. The slope was -59.7 mV/pH in pH 2.7∼8.9 and -24.3 mV/pH in pH 8.9∼11.2, respectively. A log plot of peak currents (ip) vs. concentrations showed a linearity at the concentrations between 4.8 ${\times}$ 10$^{-7}$ M and 6.2 ${\times}$ 10$^{-5}$ M (0.16 ppm∼20 ppm) chloramphenicol in pH 8.0 ammonium buffer. Between the DPP method and the reference method measuring absorbance at 278 nm, the correlation coefficient was 0.996, which means an excellent linearity. The DPP method was able to detect degradation products of chloramphenicol in mild alkaline solution (pH = 8.0) more distinctly than the spectrophotometric method.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.3
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• pp.153-158
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• 2020

In this study, a numerical approach for evaluating the resisting capacity of a partial concrete-filled steel tube (CFST) column is introduced. By strengthening the plastic hinge part of a traditional reinforced concrete column with a steel tube, a partial CFST shows a similar bending moment capacity as that of a full CFST column but with reduced material cost. To conduct an elaborate numerical analysis of a partial CFST column, an improved bond-slip model is applied to a finite element (FE) model at the interface between the steel tube and in-filled concrete. This numerical model is verified through the results of a double curvature bending-compression test. A parametric study with the proposed numerical model is used to obtain the load moment interaction diagrams for evaluating the resisting capacity based on various dimensions. Finally, the required strengthening length is estimated for each degree of thickness of the steel tube, and the failure mechanism of the partial CFST column based on the dimensions of the steel tube are identified.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.61-66
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• 2009

Purpose: Glomerular filtration rate (GFR) is considered as the best overall index for the level of renal function, diagnosis of doubtful kidney disease, progress observation from chronic kidney disease and is measured with the various methods. In this study, We measured standard GFR by Gates method and attempted to compare the result with serum creatinin-based, Cockcroft-Gault(C-G) formula and Modification of Diet in Renal Disease (MDRD) formula. Materials and methods: 217 patients (127 men, 90 women, mean age $51.3{\pm}16.9$) with various renal function were examined. we compared the GFR using $^{99m}Tc$-DTPA (Gates), C-G formula and MDRD formula. Results: Significant correlations were noted between 2 different GFR estimates (from C-G formula: r=0.864, p<0.0001, MDRD formula: r=0.831, p<0.0001) and $^{99m}Tc$-DTPA (Gates) GFR. Average of serum creatinine (Scr) was measured with $3.0{\pm}3.1\;mg/dL$, In patients with normal renal function (Scr<1.5 mg/dL), $^{99m}Tc$-DTPA (Gates) GFR was statistically significant to C-G formula (p<0.0001) and MDRD formula (p<0.0001). In patients with mild to moderate renal insufficiency (1.5$^{99m}Tc$-DTPA (Gates) GFR was not statistically significant to C-G formula (p=0.181) and MDRD formula (p=0.127). In patients with severe renal insufficiency (Scr>4.0mg/dL), $^{99m}Tc$-DTPA (Gates) GFR was statistically significant to C-G formula and MDRD formula (p<0.0001). Conclusions: Glomerular filtration rate using Gates method was closly correlated to C-G formula and MDRD formula. In patients with normal renal function, $^{99m}Tc$-DTPA (Gates) GFR was significantly lower than C-G formula and MDRD formula. In patients with mild to moderate renal insufficiency, $^{99m}Tc$-DTPA (Gates) GFR was simmilar with C-G formula and MDRD formula. In patients with severe renal insufficiency, $^{99m}Tc$-DTPA (Gates) GFR was significantly higher than C-G formula and MDRD formula. None of the three different methods was clearly superior to the others.

• Korean Journal of Food Science and Technology
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• v.45 no.3
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• pp.293-298
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• 2013

We aimed to provide the basic data for the development of a beverage using the juices from bioresources from Jeju. Our results show that pH and $^{\circ}Bx$ of the bioresources ranged 2.0-6.5 and 3.3-16.8, respectively. Rubus coreanus Miquel juice had the highest total phenol content (47.3 mg gallic acid equivalent (GAE)/100 mL). Citrus sphaerocarpa juice showed higher rates of 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging (86.8%) than those of other juices. However, the oxygen radical absorbance capacity (ORAC) value ($2,409.5{\mu}M$ TE/mL) of Citrus sudachi Hort. ex Shirai juice was higher than those of other juices. A high correlation (R=0.7343) was observed between the pH and ORAC values for the 20 bioresources. Furthermore, a high correlation (R=0.8752) was found between the phenolic contents and DPPH radical scavenging for the 5 citrus fruits. These results suggest that the bioresources in Jeju could be used as natural antioxidants for the development of functional foods, including healthy beverages.

• Journal of Nutrition and Health
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• v.47 no.1
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• pp.33-44
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• 2014

Purpose: Elevated serum phosphorus and potassium levels are a major problem for hemodialysis (HD) patients. Hyperphosphatemia and hyperkalemia are closely related to intake of dietary phosphorus and potassium. Methods: This study was conducted in order to investigate the effects of food consumed on serum phosphorus and potassium levels in 48 HD patients (20 males and 28 females). We collected anthropometric data, biochemical parameters, and dietary data of the subjects. Dietary data for usual intake were obtained by use of a food-frequency questionnaire (FFQ) consisting of 21 food items. Results: The mean body mass index (BMI) was $22.2{\pm}3.0kg/m^2$, mean serum phosphorus level was $4.50{\pm}1.52mg/dl$, and mean serum potassium level was $4.74{\pm}0.73mEq/l$. Hyperphosphatemia (> 4.5 mg/dl) was found in 45.8% of subjects, and hyperkalemia (> 5.0 mEq/l) in 35.4%. Subjects who took medication only were 56% of total, and those who took medication with dietary therapy were 27%. Patients with medication and dietary therapy showed significantly lower serum phosphorus levels compared to patients with medication only (p < 0.05). Mean duration of HD was $7.9{\pm}7.3$ years and it showed positive correlation with serum potassium levels (p < 0.05). Serum phosphorus levels showed positive correlation with intake of mixed grains and soybean milk (p < 0.05). Serum potassium levels showed positive correlation with intake of mixed grains (p < 0.01), potatoes, fish, and high-potassium vegetables (p < 0.05). On the other hand, intake of white rice showed negative correlation with serum potassium levels (p < 0.05). Conclusion: The results of our study suggest that intake of white rice rather than mixed grains is an important factor in sustaining normal serum phosphorus and potassium levels. In addition, limiting intake of soybean milk, potatoes, and fish to under three serving per week is recommended. Finally, conduct of a strict dietary therapy along with medical treatment is desirable because inappropriate food intake increases serum phosphorus and potassium levels to a higher than normal range.

• Korean journal of food and cookery science
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• v.16 no.4
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• pp.367-371
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• 2000

In order to study the tenderizing effect of proteolytic enzymes in fruits, beef(M. semimembranosus) was marinated with meat sauce containing each fruit juices. After cooking, the shear force was measured by Rheometer and evaluated the sensory properties of beef by quantitative descriptive analysis method. The results are as follows: 1. The combination ratio of meat sauce:water was 2:1 with pH 5.0∼5.5 showed the max. tenderness. 2. As a result of shear force test, the decrease of shear force was pineapple>papaya>fig>kiwifruit>pear: especially, pineapple, papaya and fig tendered the beef significantly comparing with pear and kiwifruit at p<0.001. 3. The tendering effect of pineapple and papaya on the meat showed significant difference (p<0.01) comparing with pear in tenderness and overall acceptability by sensory evaluation; and there was a significant difference between pear and papaya in taste (p<0.05). 4. There was highly significant correlation between mechanical tenderness and sensory properties: correlation of fruit and mechanical tenderness was -.877(p<0.01); between mechanical tenderness and overall acceptability, r = .532(p<0.01); between fruit and sensory tenderness, r = .495(p<0.01); between mechanical tenderness and sensory tenderness, r = .490(p<0.01). At p<0.05, between taste and juiciness, r = .208.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.9 no.1
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• pp.48-57
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• 2006

Purpose: To investigate the correlation of the serum leptin, adiponectin, and leptin/adiponectin ratio with metabolic disorders in the childhood obesity. Methods: Fifty children (25 obese and 25 non-obese) were recruited in the pediatric outpatient clinic of Chosun University Hospital from January 1st to June 30th 2005. Adiponectin, leptin, anthropometric parameters, glucose, LDL-cholesterol, HDL-cholesterol, total cholesterol, triglyceride, and insulin levels were measured. The correlations of leptin and adiponectin levels with anthropometric parameters, glucose, insulin and lipids were analyzed by Pearson's correlation coefficients. Results: Insulin and leptin levels of the obese group were significantly higher than those of the non-obese group (p<0.05, p<0.001 respectively). HDL-cholesterol and adiponectin levels of the obese group were significantly lower than those of the non-obese group (p<0.005, p<0.05 respectively). In the obese group, leptin level was positively correlated with BMI and the percentage of body fat, but negatively correlated with adiponectin level. Moreover, adiponectin level of the obese group was negatively correlated with BMI and the percentage of body fat, but positively correlated with leptin level. In the non-obese group, only insulin level was positively correlated with adiponectin. In the obese group, leptin/adiponectin ratio was positively correlated with the percentage of body fat and leptin level. Also, leptin/adiponectin ratio was positively correlated with BMI and the percentage of body fat in the non-obese group. Conclusion: Leptin, adiponectin, and leptin/adiponectin ratio did not appear to have a major role linking various metabolic disorders in the childhood obesity, even though they were strongly associated with obesity indices. Also, leptin/adiponectin ratio was associated with obesity indices even in non-obese children.