• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3074-3078
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• 2014

We implemented a dual-band slot-coupled patch (SCP) antenna for the external access point (AP) of the wireless local area network (WLAN) band. The antennas consist of two radiators on three layers. The first radiator is a slotted bow tie antenna operating at the 2.4-2.483 GHz band. The second radiator is a patch antenna with parasitic elements operating at 4.095-5.845 GHz. The high gain and broad bandwidth is important element of wireless access. To enhance the bandwidth, a coupled feeding was used in the first radiator and a parasitic patch was used in the second radiator. We used a parasitic patch and chock to improve the directivity and isolation in both radiators. The porposed antenna was designed by EM simulation tool and measured. The S11 of the antenna was less than -11dB (VSWR 1.8:1) at operating frequency. The peak gain was more than 6 dBi in the first antenna and more than 8 dBi in the second antenna.

• Journal of Korean Academy of Nursing
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• v.35 no.3
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• pp.621-630
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• 2005

Purpose: The purpose of this study was to -retrospectively describe the childhood sports activity level of Korean adult men and women and to determine whether a higher level of childhood sports activity was positively associated with adult bone mineral density. Methods: A cross-sectional study of 100 Korean men (n=40) and women (n=60) was completed. Participants completed a detailed lifetime sports activity questionnaire and had their bone mineral density of the femur and lumbar spine measured using dual energy x-ray densitometry (DEXA). All sports activities were classified into four categories of peak strain score on the basis of ground reaction forces (GRF). Results: During the age of high school, women and men who participated in a high intensity sports activity demonstrated higher bone density in the femur site after adjustment for the effects of body weight, fat body mass, lean body mass, the level of calcium intake, and breast feeding period than those who did not participate in sports activity at all. Conclusion: These results highlight the need to participate in high intensity sports activity during high school age as a means of increasing peak bone mass in the femur site.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.45-52
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• 2017

This paper deals with the operation strategy of reactive power in a multi-infeed HVDC (MIHVDC) system, in which several converters are connected to the same or nearby separate AC buses. The potential problems concerning a MIHVDC system when feeding a weak AC network are as follows: the need for coordination of the recovery control, the possibility of voltage instability or low quality of the area connected to the MIHVDC system, and the risk of mutual commutation failures. These problems in MIHVDC systems are similar to those in single-infeed HVDC (SIHVDC) systems, but the differences with the phenomenon of the SIHVDC system are the interactions between converters. The main reason for the potential problems of HVDC systems (MIHVDC or SIHVDC) is voltage variation; therefore, to mitigate the voltage variations, the performances of the HVDC system should be enhanced. Consequently, to mitigate the potential problems of MIHVDC systems, several solutions are suggested in this study, including installing STATCOM and installing a line arrester on the tower. The study results will be applied to a multi-infeed HVDC system in Korea.

• Journal of Microbiology and Biotechnology
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• v.5 no.2
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• pp.100-104
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• 1995

Production of $poly-{\beta}-hydroxybutyrate$ (PHB) in a strain of Azotobacter chroococcum, a nitrogen-fixing bacteria, was investigated at various levels of nitrogen and oxygen. Feeding nitrogen source increased both cell growth and PHB accumulation. Oxygen supply appeared to be one of the most important operating parameters for PHB production. Both cell growth and PHB accumulation increased with the sufficient supply of air in the fed-batch fermentation of the strain. However, it was also noted that keeping the oxygen level under limited condition was critical to achieve high PHB productivity. A high titer of PHB (52 g/l) with a high cellular content (60%) was obtained after 48 hr of fed-batch operation by controlling the oxygen supply. Dual limitation of nitrogen and oxygen did not further increase the PHB accumulation probably due to the greater demand for reducing power and ATP for nitrogen fixation.

• Journal of Nutrition and Health
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• v.29 no.9
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• pp.943-949
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• 1996

Bone mineral density depends largely on the status of dietary minerals such as Ca, P, Mg, and F and proteins, physical activities, parathyroid hormone(PTH), calcitonin(CT), and vitamin D. The decrease of bone density often results in bone fractures and osteoporosis which is prevalent among postmenopausal women. This study was intended to examine the role of parathyroid hormone, calcitonin and cholecaliferol in bone density of mice that were fed different dual photon energy beams. We have measured three major parts of the bone : whole body, head and femur. The results are summarized as follows : 1) Bone mineral density (BMD) was more increased by feeding high Ca diet compared to that of the low Ca diet. 2) Both PTH and Vit D3 enhanced BMD in all of the different Ca levels. 3) When the dietary Ca was deequate CT showed a synergistic effect with PTH in boosting bone density, while CT+Vit D3 showed a negative effect. 4) CT tended to inhibit the effect of increasing bone density by PTH and Vit D3 in medium and low Ca groups. 5) The effect of increasing bone density by PTH in the head of mouse increased when dietary Ca was lower : The increment of bone density by PTH in high, medium, and low Ca was 3%, 8%, 19%, respectively. 6) Femur bone density was affected significantly by dietary Ca levels than hormones. The above observations indicate that bone mineral density can be improved by high dietary Ca and hormone injections including PTH, CT and cholecalciferol, and thus proper dietary and hormonal treatment may be used in preventing bone fractures and osteoporosis.

• Journal of Advanced Navigation Technology
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• v.14 no.2
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• pp.170-175
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• 2010

This article proposed polarization selective antenna for UHF RFID system. The proposed antenna is consist of microstrip patch antenna with dual feeding and two SPDT switches and a SP4T switch and 3dB hybrid coupler. Through control of voltage of switches, the proposed reader antenna can select horizontally linear polarization, vertically linear polarization, left-hand circular polarization (LHCP) and right hand circular polarization (RHCP). The proposed reader antenna satisfied 2:1 VSWR at 902MHz ~ 928MHz. and 3dB under AR(axial ratio). And it can select appropriative polarization with user environment and tag polarization. So it minimize PLF and increased reading distance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.4
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• pp.807-811
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• 2001

In this paper we proposed a dual-frequency circular sector microstrip antenna with orthogonal polarized modes and high isolation between the two feeding ports. And then we designed a transceiver operating at 5.6 GHz for transmitting and at 5.5 GHz for receiving. The good isolation provided by the proposed antenna is used as the basis for the transmit-receive filtering of transceiver. The operating frequencies and polarization characteristics of the proposed antenna is calculated by using a cavity model. The 5-parameters and radiation patterns of the antenna are measured. A power amplifier and a low noise amplifier are designed and integrated with antenna to make a transceiver, which has about 13dB transmitting gain and about 8㏈ receiving gain.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.6
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• pp.459-466
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• 2019

Dipeptidyl peptidase (DPP)-4 inhibitors, or gliptins, are a class of oral hypoglycemic drugs that have been widely used as a second-line treatment for type 2 diabetes. Gliptins, which were introduced for clinical use a decade ago, have been shown to be beneficial against nonalcoholic fatty liver disease/nonalcoholic steatohepatitis (NASH) in animals and humans. Cenicriviroc (CVC), a dual antagonist of C-C chemokine receptor type 2 and 5, is currently under investigation against NASH and fibrosis. It was previously discovered that evogliptin (EVO) reduces hepatic steatosis in diet-induced obese animals but the effectiveness of EVO on NASH remains unexplored. Here, we compared the effectiveness of EVO and CVC against NASH and fibrosis in mice fed a high-fat and high-fructose diet (HFHF). Biochemical and histological analyses showed that mice fed a HFHF for 20 weeks developed severe hepatic steatosis and inflammation with mild fibrosis. Administration of EVO (0.2% wt/wt) for the last 8 weeks of HFHF feeding significantly reduced hepatic triglyceride accumulation, inflammation, and fibrosis as well as restored insulin sensitivity, as evidenced by lowered plasma insulin levels and the improvement in insulin tolerance test curves. Treatment of mice with CVC (0.1% wt/wt) inhibited hepatic inflammation and fibrogenesis with similar efficacy to that of EVO, without affecting hepatic steatosis. CVC treatment also reduced plasma insulin concentrations, despite no improvement in insulin tolerance. In conclusion, EVO administration efficiently ameliorated the development of NASH and fibrosis in HFHF-fed mice, corroborating its therapeutic potential.

• International Journal of Industrial Entomology and Biomaterials
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• v.39 no.1
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• pp.34-38
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• 2019

In this study, we investigated the effect of silkworm, and its by-products on exercise endurance, muscle mass, and fatigue recovery using ICR mice model. Powders of silkworm, pupae, dongchunghacho, and silk powder were suspended in water and feed to mice for 2 weeks. The forced swimming time was increased by 4.3, 4.1 and 2.8 seconds after silkworm, pupae, and dongchughacho administration compared to DW fed group. Increases in exercise ability were achieved by difference mechanism according to feeding materials. Pupae increased muscle mass by 129% compared with the control group which may effect on elongation of swimming time. Dongchunghacho improved the plasma concentrations of fatigue markers such as creatinine, blood urea nitrogen (BUN), and D-lactate. Silkworm administration showed dual effect, the muscle mass induction (114% vs. control) and anti-fatigue (plasma creatinine, BUN, and D-lactate were 63, 75, and 78% vs. con) effect which contributed most elongated swimming time. In conclusion, silkworm and its by-products including pupae and dongchunghacho with the predominant protein and bioactive components improved muscle mass and showed anti-fatigue effect which could promote exercise performance ability.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.12
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• pp.1340-1350
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• 2009

The design and implementation of planar Active Phased Array Antenna System are described in this paper. This Antenna system operates at X-band with its bandwidth 10 % and dual polarization is realized using dual slot feeding microstrip patch antenna and SPDT(Single Pole Double Through) switch. Array Structure is $16\times16$ triangular lattice structure and each array is composed of TR(Transmit & Receive) module with more than 40 dBm power. Each TR module includes digital attenuator and phase shifter so that antenna beam can be electronically steered over a scan angle$({\pm}60^{\circ})$. Measurement of antenna pattern is conducted using a near field chamber and the results coincide with the expected beam pattern. From these results, it can be convinced that this antenna can be used with control of beam steering and beam shaping.