• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.3
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• pp.55-64
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• 2013

In this paper, a new topology which can add a small reactor in series to a condenser-bank type reactive power compensator to limit current is proposed. And also the proposed topology can add or remove a power condenser safely without any addition of inrush-current suppression resistance. The proposed method tests variable resistance of the drain source of a switching device which is controlled by gate voltage in a two-way switch with a diode rectifier and FET switch. In other words, the proposed method is a inrush-current suppression method with the structure of variable resistance. In particular, the proposed method creates smooth current without any resonance in inrush-current as well as is not limited by the time of switch on and off.

• Membrane and Water Treatment
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• v.12 no.1
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• pp.23-35
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• 2021

A POM-membrane was fabricated by immobilizing a keggin type polyoxometalate (POM) H5PV2Mo10O40 onto the surface of microporous flat-sheet polymeric polyvinylidene fluoride (PVFD) membrane using a chemical deposition method. The POM-membrane was characterized by FT-IR, SEM and EDX to confirm existing of the POM onto the membrane surface. The POM-membrane was used to remove an anionic textile dye (Reactive Black 5 named as an RB5) from aqueous phases with a cross-flow membrane filtration and a batch adsorption system. The dye removal efficiency of the POM-membrane using the cross-flow membrane filtration system and the batch adsorption system was about 88% and 98%, respectively. The influence factors such as contact time, adsorbent dosage, pH, and initial dye concentration were investigated to understand the adsorption mechanism of the RB5 dye onto the POM-membrane. To find the best fitting isotherm model, Langmuir, Freundlich, BET and Harkins-Jura isotherm models were used to analyze the experimental data. The isotherm analysis showed that the Langmuir isotherm model was found to the best fit for the adsorption data (R2 = 0.9982, qmax = 24.87 mg/g). Also, adsorption kinetic models showed the pseudo second order kinetic model was found the best model to fit the experimental data (R2 = 0.9989, q = 8.29 mg/g, C0 = 15 ppm). Moreover, after four times regeneration with HNO3 acid, the POM-membrane showed high regenerability without losing dye adsorption capacity.

• Applied Microscopy
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• v.27 no.1
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• pp.1-12
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• 1997

Dorsal and ventral epithelium of leech, Whitemenia edentula, were observed, using both light and electron-microscope. Results are as follows. Epithelia are composed of simple columnar or irregularly-shaped epithelium, the transveral folds were seen in the cross-sectioned dorsal and ventral epithelia, but only longitudinal folds(depth $500{\mu}m$, width $350{\mu}m$) were discovered in the ventral epithelium. As to muscular tissue under the dorsal epithelium of Whitemenia edentula, that of longitudinal muscle layer is thicker and more developed than that of circular muscle layer. Seven gland cells (type-A, B, C, D, E, F and H cells) and one pigment cell (type-G cell) were discovered in the whitemenia edentula. Those were identified as three kinds of the neutral mucopolysaccharide granoles (type-A, B and F cells), two kinds of acidic mucopolysaccharide granules (type-C and D cells), and two kinds of non-reactive granules respectively (type-E and F cells). The glanules of the type-A and type-B gland cells ae electronly high-dense, and surrounded by the muscular tissue. As to the distribution of gland cells, the type-A, type-B, type-C, type-D, type-I and type-H gland cells were discovered only between the connective tissue and the circular muscle layer, while type-F gland cells were discovered only between tile circular muscle layer and the longitudinal muscle layer.

• Journal of the Korean Society of Food Culture
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• v.35 no.5
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• pp.493-502
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• 2020

The objective of this study was to investigate the effects of dietary vitamin B intake on biomarkers related to lipid metabolism, inflammation and blood glucose control, that are important in the development of type 2 diabetes and its complications. Seventy-six adults (42 males, 34 females) were recruited from a group of diabetes patients who had visited the medical center for treatment. Data on anthropometric characteristics and dietary intake of thiamine, riboflavin, niacin, vitamin B₆ and folate were collected using 24-hour diet recall and the CAN Pro 4.0 program. Also, data on clinical indices such as serum lipids, blood pressure, high-sensitivity C-reactive protein (hs-CRP), hemoglobin A1c (HbA1c) and homeostasis model assessment 2-insulin resistance (HOMA2-IR) were collected and analyzed for correlation with dietary vitamin B intake. Results from the dietary intake survey showed that riboflavin and folate intake (in males) and folate intake (in females) were below the Dietary Reference Intake for Koreans. Statistical analysis revealed a negative correlation between hs-CRP and dietary intake of B vitamins. Riboflavin intake was inversely associated with systolic blood pressure after adjustments for age, BMI, smoking, alcohol consumption, exercise, ingestion of diabetes mellitus medication and energy intake (p<0.05). Our results suggest that dietary vitamin B may influence inflammation and consequently may help in better management of type 2 diabetes.

• The Korean Journal of Food And Nutrition
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• v.26 no.4
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• pp.909-918
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• 2013

The objective of this study is to investigate the effects of dietary nutrient intakes for markers of blood glucose and inflammation which is important to the progress of type 2 diabetes and the development of its complications. For this study, 76 adults with diabetes (42 males, 34 females) were recruited from a group of patients who had visited the department of endocrine medicine. Data on anthropometric characteristics, clinical indices such as hemoglobin A1c (HbA1c) and C-reactive protein (CRP), and dietary nutrient intakes were collected. Our results have shown that 66% of subjects were either overweight or obese. Serum analysis indicates that levels of C-peptide, glucose, HbA1c, CRP, triglyceride, LDL-cholesterol were higher than normal range. Results from the dietary nutrient intake survey displayed that intakes of cholesterol and sodium were higher than Dietary Reference Intakes for Koreans. On the contrary, folate intake was lower than the guideline. Within the females, energy contribution from carbohydrate was higher than Korean Diabetes Association guideline. Statistical analysis has revealed a negative correlation between serum HbA1c level and dietary intakes of polyunsaturated fatty acid (PUFA), n-3 PUFA, ${\beta}$-carotene and vitamin E after adjustments for age, BMI, smoking habits, alcohol consumption, exercise and ingestion of diabetes mellitus medication (p<0.05). Serum CRP level was inversely associated with dietary intakes of carbohydrate, protein, vitamin C and fiber (p<0.05). Our results suggest that dietary nutrient intakes may influence the levels of HbA1c and CRP, and subsequently, it may help in the management/treatment of type 2 diabetes.

• Bulletin of the Korean Chemical Society
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• v.29 no.7
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• pp.1359-1363
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• 2008

Second-order rate constants have been determined spectrophotometrically for reactions of 2,4-dinitrophenyl 2- thiophenecarboxylate (2) with a series of alicyclic secondary amines in 80 mol % $H_2O$/20 mol % DMSO at 25.0 ${\pm}$ 0.1 ${^{\circ}C}$. The Brønsted-type plot exhibits a downward curvature, i.e., the slope decreases from 0.74 to 0.34 as the amine basicity increases. The $pK_a$ at the center of the Brønsted curvature, defined as $pK_a^o$, has been determined to be 9.1. Comparison of the Brønsted-type plot for the reactions of 2 with that for the corresponding reactions of 2,4-dinitrophenyl 2-furoate (1) suggests that reactions of 1 and 2 proceed through a common mechanism, although 2 is less reactive than 1. The curved Brønsted-type plot has been interpreted as a change in RDS of a stepwise mechanism. The replacement of the O atom in the furoyl ring by an S atom (1 $\rightarrow$ 2) does not alter the reaction mechanism but causes a decrease in reactivity. Dissection of the apparent second-order rate constants into the microscopic rate constants has revealed that the $k_2/k_{-1}$ ratio is not influenced upon changing the nonleaving group from furoyl to thiophenecarbonyl. However, $k_1$ has been calculated to be smaller for the reactions of 2 than for the corresponding reactions of 1, indicating that the C=O bond in the thiophenecarboxylate 2 is less electrophilic than that in the furoate 1. The smaller k1 for the reactions of 2 is fully responsible for the fact that 2 is less reactive than 1.

• The Korean Journal of Food And Nutrition
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• v.29 no.2
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• pp.290-299
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• 2016

This study was conducted to determine the association between dietary calcium intake and biomarkers related to lipid and glucose metabolism and inflammation in Korean patients with type 2 diabetes. Seventy-five subjects (41 males, 34 females) were recruited from a group of patients who had visited the department of endocrine medicine. Data on anthropometric characteristics, clinical indices such as hemoglobin A1c and C-reactive protein (CRP), and dietary nutrient intakes were collected. Subjects were divided into three groups on the basis of their calcium intake [< EAR (below estimated average requirement), EAR-RNI (between EAR and recommended nutrient intake), > RNI (above RNI)]. Average calcium intake of < EAR, EAR-RNI, > RNI groups were $462.7{\pm}18.7$, $649.7{\pm}12.8$, and $895.7{\pm}21.7mg$, respectively. Energy intake was not different among groups but intakes of protein, total and saturated fatty acids were significantly higher in > RNI group than < EAR group. Analysis of covariance revealed that HDL cholesterol level was significantly higher in EAR-RNI group, as compared to < EAR group after adjustment with confounders such as age, sex, BMI and energy intake (p < 0.05). Levels of CRP and homeostasis model assessment 2-insulin resistance (HOMA2-IR) were significantly lower in EAR-RNI group. Total cholesterol level was higher in EAR-RNI and > RNI groups, although within the normal range. Our results suggest that dietary calcium intake may influence the levels of HDL-cholesterol, CRP and HOMA2-IR and subsequently, help management/treatment of type 2 diabetes patients.

• Korean Journal of Materials Research
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• v.13 no.8
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• pp.519-523
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• 2003

We report the synthesis of cubic spinel $ZnCo_2$$O_4$thin films and the tunability of the conduction type by control of the oxygen partial pressure ratio. Zinc cobalt oxide films were grown on$ SiO_2$(200 nm)/Si substrates by reactive magnetron sputtering method using Zn and Co metal targets in a mixed Ar/$O_2$atmosphere. We found from X-ray diffraction measurements that the crystal structure of the zinc cobalt oxide films grown under an oxygen-rich condition (the $O_2$/Ar partial pressure ratio of 9/1) changes from wurtzite-type $Zn_{1-x}$ $Co_{X}$O to spinel-type $ZnCo_2$$O_4$with the increase of the Co/Zn sputtering ratio,$ D_{co}$ $D_{zn}$ . We noted that the above structural change accompanied by the variation of the majority electrical conduction type from n-type (electrons) to p-type (holes). For a fixed $D_{co}$ $D_{zn}$ / of 2.0 yielding homogeneous spinel-type $_2$O$ZnCo_4$films, the type of the majority carriers also varied, depending on the$ O_2$/Ar partial pressure ratio: p-type for an $O_2$-rich and n-type for an Ar-rich atmosphere. The maximum electron and hole concentrations for the Zn $Co_2$ $O_4$films were found to be 1.37${\times}$10$^{20}$ c $m^{-3}$ and 2.41${\times}$10$^{20}$ c $m^{-3}$ , respectively, with a mobility of about 0.2 $\textrm{cm}^2$/Vs and a high conductivity of about 1.8 Ω/$cm^{-1}$ /.

• Applied Science and Convergence Technology
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• v.26 no.5
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• pp.118-128
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• 2017

The scope of this work is to determine and compare the effect of electron temperature ($T_e$) and number density ($N_e$) on the yield rate and concentration of reactive chemical species ($^{\bullet}OH$, $H_2O_2$ and $O_3$) in an argon, air and oxygen injected negative DC (0-4 kV) capillary discharge with water flow(0.1 L/min). The discharge was created between tungsten pin-to pin electrodes (${\Phi}=0.5mm$) separated by a variable distance (1-2 mm) in a quartz capillary tube (2 mm inner diameter, 4 mm outer diameter), with various gas injection rates (100-800 sccm). Optical emission spectroscopy (OES) of the hydrogen Balmer lines was carried out to investigate the line shapes and intensities as functions of the discharge parameters such as the type of gas, gas injection rate and inter electrode gap distances. The intensity ratio method was used to calculate $T_e$ and Stark broadening of Balmer ${\beta}$ lines was adopted to determine $N_e$. The effects of $T_e$ and $N_e$ on the reactive chemical species formation were evaluated and presented. The enhancement in yield rate of reactive chemical species was revealed at the higher electron temperature, higher gas injection rates, higher discharge power and larger inter-electrode gap. The discharge with oxygen injection was the most effective one for increasing the reactive chemical species concentration. The formation of reactive chemical species was shown more directly related to $T_e$ than $N_e$ in a flowing water gas injected negative DC capillary discharge.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.155.1-155.1
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• 2015

Nowadays, Plasma has been used in biological, medical such as wound healing, plant grow, killing cancer. When plasma generated, UV light and ROS(Reactive oxygen species), RNS(Reactive nitrogen species) can generated and those things effect to biological material. So we made simple plasma device using needle type of electrode and generated plasma. We used three kinds of gas and measured applied voltage and current. Also we observed optical emission spectrum. Using deuterium ramp, we can observed absorption spectrum and calculated radical density by lambert-beer's law. It is around ~1016cm3. And we can see the time-resolved absorption spectrum from monochromator, PMT(photo multiply tube), IV-converter, oscilloscope.