• Korean Journal of Community Nutrition
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• v.13 no.2
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• pp.288-297
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• 2008

It has been reported frequently that clinical features of gallstone disease in Korean were similarly changing to those of Occidentals. This changing was thought to be due to Westernized lifestyle and dietary patterns in Korean. The purpose of this study was to investigate the nutritional risk factor among patients with gallstone. The subjects of this study were 90 gallstone group with biliary stone as confirmed by cholecystectomy and 111 control group with no biliary stone as confirmed by ultrasonography adjusted according to age and gender. Anthropometric indices and biomarkers were measured and dietary habit as well as nutrient consumption pattern were investigated using a structured checklist of health-related eating behavior and a semi-quantitative food frequency questionnaire. The mean age was higher in GG (gallbladder stone patient group) than CG (control group). The average BMI and WHR (waisthip ratio) tended to be higher than those in CG. WC (waist circumference) and WHR of women in GG were significantly higher than in CG. GG had lower levels in TC (p < 0.01), LDL-C (p < 0.05), and HDL-C (p < 0.05), but higher FBG levels (p < 0.001). GG tended to be associated with lower physical activity and more frequent consumption of meat, meats with high fat and high sugar content food. The consumption levels of fiber (p < 0.05), vitamin C (p < 0.05), calcium (p < 0.01) in GG were significantly lower than in CG. These findings showed that the association with incidence of gallbladder stone and anthrophometric indices and dietary consumption patterns. Further study may be necessary to elucidate the dietary risk factors in the changing patterns of gallstone disease.

• Smart Structures and Systems
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• v.18 no.3
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• pp.405-423
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• 2016

In this study, the feasibility of using telecommunication single-mode optical fiber (SMF) as a distributed fiber optic strain and crack sensor was evaluated in concrete pavement monitoring. Tensile tests on various sensors indicated that the $SMF-28e^+$ fiber revealed linear elastic behavior to rupture at approximately 26 N load and 2.6% strain. Six full-scale concrete panels were prepared and tested under truck and three-point loads to quantify the performance of sensors with pulse pre-pump Brillouin optical time domain analysis (PPP-BOTDA). The sensors were protected by precast mortar from brutal action during concrete casting. Once air-cured for 2 hours after initial setting, half a mortar cylinder of 12 mm in diameter ensured that the protected sensors remained functional during and after concrete casting. The strains measured from PPP-BOTDA with a sensitivity coefficient of $5.43{\times}10^{-5}GHz/{\mu}{\varepsilon}$ were validated locally by commercial fiber Bragg grating (FBG) sensors. Unlike the point FBG sensors, the distributed PPP-BOTDA sensors can be utilized to effectively locate multiple cracks. Depending on their layout, the distributed sensors can provide one- or two-dimensional strain fields in pavement panels. The width of both micro and major cracks can be linearly related to the peak strain directly measured with the distributed fiber optic sensor.

• Journal of Korean Medicine for Obesity Research
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• v.21 no.2
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• pp.59-68
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• 2021

Objectives: We investigated the effects of Clean-DM4 (C-DM4), a polyherbal extract consisting of Coptidis Rhizoma, Salviae Miltiorrhiza Radix, and Cinnamomi Cortex on high fat diet (HFD)-induced obesity and diabetes in mice. Methods: The C57BL/6 mice (6 weeks) were fed a HFD for 8 weeks and then administrated with C-DM4 extract at 500 mg/kg (p.o.) once daily for 4 weeks. The changes of body weights, calorie intakes, and fasting blood glucose (FBG) levels were measured in mice. The serum levels of glucose, insulin, total cholesterol, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were measured in mice by enzyme-based assay. It was also observed the histological changes of pancreas, liver, and fat tissues with hematoxylin and eosin (H&E) staining. Results: The increase of calorie intakes and FBG levels in HFD-induced obesity mice was significantly decreased by oral administration of C-DM4 extract. C-DM4 extract administration was significantly reduced the increased levels of glucose, insulin, total cholesterol, AST, and ALT in obesity mice. In addition, C-DM4 extract inhibited lipid droplet accumulation in liver tissues of obesity mice, hyperplasia of pancreatic islets, and enlargement of adipocytes in adipose tissues. Conclusions: Our study indicates that C-DM4 extract could help improve obesity and to prevent diabetes progression.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.257-264
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• 2010

Generally, estimations on the displacement as an important factor in evaluating the safety of large structures could be a barometer assessing whether the condition of the structure is deteriorating. Practically, it is not easy how to measure the displacement response to large structures like suspension bridges. In this study, as a method for estimation displacement response from strain signals, mode decomposition technique is proposed. Total displacement response is estimated by superposing quasistatic displacement response and modal displacement responses in dominant modes with larger contributions after estimating the modal displacement responses. If foiled strain gauges are used to measure strain signals, there would likely to generate electric noise, what's more, the more measuring points there are the more economic burden it could be. In order to solve such problems, fiber optic bragg-grating(FBG) sensors were used, which have multi-point measurements with no effect on electric noises. Therefore, the experiment was performed through dynamic load test of suspension bridge and plate-girder bridge to review the possibility for using mode decomposition technique.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.209-212
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• 2009

최근 국내에서 적용되고 있는 콘크리트 충진 FRP 스트럿은 시공성 및 경제성 면에서 매우 뛰어난 공법으로 주목 받고 있으나 그 설계 및 시공에 있어 아직도 불확실한 요소를 내포하고 있다. 특히 최근에는 PSC 박스 거더교에서 교폭을 늘리고 자중을 줄이기 위해 콘크리트 충진 FRP 스트럿을 설치하는 공법이 다수 시공되고 있다. 본 연구에서는 이러한 대상교량에 대해 현장시험을 실시하여 교량시스템에서의 콘크리트 충진 FRP 스트럿 거동을 분석하는데 목적이 있다. 특히 전자기파 간섭에 면역이 우수한 광센서인 FBG 센서를 기반으로 하는 계측을 실시하여 잡음이 없는 우수한 결과를 성공적으로 획득하였다. 그 결과 FRP 스트럿은 하중 재하 위치와 속도에 관계없이 압축응력 상태에 존재하고 있으며 횡방향 거동에 지배되고 있음을 확인하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.114-118
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• 2009

이 논문에서는 울돌목 시험조류발전소에 구축 중인 구조건전성 감시시스템의 계획, 설치 및 활용에 대하여 소개하였다. 현재 시험조류발전소에 설치된 센서로는 전기저항식 변형률계, 광섬유 FBG(Fiber Bragg Grating) 센서, 압전형 MFC(Macro Fiber Composite) 센서, 2축 경사계, 서보형 가속도계 등과 같은 지지구조물의 구조거동을 감시하기 위한 센서와 토크 센서, RPM 센서 등 발전 계통에 대한 감시를 위한 센서, 그리고 H-ADCP(Horizontal Acoustic Doppler Current Profiler)와 같은 외력조건에 대한 계측 장비 등이 있다. 센서 설치 후 현재까지 부분적으로 계측된 자료를 소개하고, 향후 건전성 감시시스템 개선 계획을 소개하였다.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.531-532
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• 2002

This paper present a gain-clamped L-band EDFA based on reflecting back a portion of backward amplified spontaneous emission into the erbium-doped fiber section, utilizing a fiber Bra99 grating. By using FBG with R=66.1 and 99.9%, the gain is clamped at 15.1 and 14.3㏈, respectively, with a variation of less than 0.2㏈ for an input signal power as high as -5 ㏈m. However, a small noise figure penalty is obtained, which is the consequence of the gain clamping effect.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.631-634
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• 2005

This paper has been studied a optical fiber sensor offer important advantages such as electrically passive operation, EMI immunity, high sensitivity, and multi-plexing capabilities of this technology has been the characteristic. The shift in optical fiber Bragg wavelength with mass can be expressed. Using the shift in the optical fiber Bragg grating(FBG) center wavelength due to mass change.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.201.1-201.1
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• 2016

본 연구에서는 펄스형으로 운전하는 플라즈마를 대상으로 하거나 플라즈마 특성의 빠른 변동을 파악하기 위해 1 kHz 이상의 반복율, 5 pulse burst mode와 2 J/pulse 이상의 발진특성을 갖는 Nd:YAG 레이저를 기반으로 하는 광원을 개발하기 위하여 레이저와 전원장치를 설계하였다. 전체 시스템은 MOPA(Master Oscillator Power Amplifier)형태로 구성하고 발진기는 FBG(Fiber Bragg Grating)을 반사경으로 사용한 Yb fiber 레이저를 설계하였다. 또한 설계한 레이저를 작동시킬 전원장치를 연구하였다. 정확한 스위칭과 턴온, 턴오프를 구현하기 위하여 IGBT 스위치를 적용하였고 적절한 저항을 조합하여 전류가 시간에 따라 상승하다가 스위치 턴오프에 급격히 감소하는 형태의 레이저 다이오드 구동에 적합한 삼각파와 비슷한 전류파형을 설계하였다. 추후 설계한 두 장치를 제작하여 테스트를 거친 후, VEST 내부 플라즈마 진단에 적용할 계획이다.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.168-171
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• 2004

If a research trend present in and outside the country is often seen, the structure measurement method of having used PZT and the optical fiber (FBG) will be the actual condition which has accomplished the stock. In order to manage such cracks, time, efforts and expense are required. Such a method has many difficulties in application of a structure by the difficult problem of the measurement range, and the expensive sensor price. Progressive cracks were generated by fracture of glass pipe sensor. Moreover, the experiment which can detect damage propriety by external Light Emitting Diode by damaging a glass pipe by load change with the application of switch using strain gage of a glass pipe was conducted.