• 한국추진공학회지
• /
• 제5권1호
• /
• pp.76-81
• /
• 2001

A structural test of the wind turbine rotor blade is to evaluate the uncertainty of design due to selection of material, design concepts, production processes and so on, and their possible impacts on the structural integrity. In the full-scale static strength test, the measuring parameters are strain and displacements vs. loads, weight and the center of gravity. In order to simulate the aerodynamics load, the three-point loading method is applied. There is slight difference between the measured results and the predicted results for the reference fiber volume fraction of 60% . However, the agreement between the measured results and the predicted results with the actual fiber volume fraction of 52.5% is good. Even though a slightly non-linearity from 80% loading to 100% loading exists, a linear static solution is sufficient for the design purpose due to te small amount of non-linearity. Comparison between measured and predicted strain results at the maximum thickness positions of the blade profile for 0.236R(5.56m), 0.493R(11.59m) and 0.574R(13.43m), under 20%, 40%, 60%, 80% and 100% loadings for the upper part of the blade. The predicted values are in good agreement with the measured values.

• Healthcare Informatics Research
• /
• 제24권4호
• /
• pp.335-345
• /
• 2018

Objectives: The retinal nerve fiber layer (RNFL) is a site of glaucomatous optic neuropathy whose early changes need to be detected because glaucoma is one of the most common causes of blindness. This paper proposes an automated RNFL detection method based on the texture feature by forming a co-occurrence matrix and a backpropagation neural network as the classifier. Methods: We propose two texture features, namely, correlation and autocorrelation based on a co-occurrence matrix. Those features are selected by using a correlation feature selection method. Then the backpropagation neural network is applied as the classifier to implement RNFL detection in a retinal fundus image. Results: We used 40 retinal fundus images as testing data and 160 sub-images (80 showing a normal RNFL and 80 showing RNFL loss) as training data to evaluate the performance of our proposed method. Overall, this work achieved an accuracy of 94.52%. Conclusions: Our results demonstrated that the proposed method achieved a high accuracy, which indicates good performance.

• 한국결정성장학회지
• /
• 제30권6호
• /
• pp.264-270
• /
• 2020

사용자 중심의 서비스디자인 방법론을 통한 디자인개발을 진행하고 시제품 제작 시 소재 선정 기준에 대해 조사분석하여 선정된 소재인 CFRP(Carbon Fiber Reinforced Plastics) CNT(Carbon Nano Tube)를 동물용 X-ray 디텍터 패널부분에 적용하여 제품디자인 및 시제품 개발을 진행하고 CFRP CNT 패널을 적용하여 완성된 시제품을 Drop 테스트, 전면 외압 강도 시험, 방진/방수 성능 시험을 진행하여 야외환경에서 사용하는 휴대가능한 동물용 X-ray 디텍터로 활용이 가능한 제품임을 확인하였다.

• 대한조선학회논문집
• /
• 제58권6호
• /
• pp.431-439
• /
• 2021

The Carbon Fiber Reinforced Plastic (CFRP) material is recently widely used in the composite industry with excellent rigidity and lightweight properties. A ship shaft system requires high standards of safety on torsional strength capacity. The purpose of this study is to verify the applicability of a CFRP shaft system to take the place of metal shaft systems for ships from a viewpoint of torsional strength. Selection of materials and manufacturing method are executed then two geometrically scaled CFRP shaft system models were designed and manufactured with three-layer patterns. The models were used for a series of torsion tests under single and repeated torsional loading conditions. Detailed design and manufacturing methods for a CFRP ship shaft system are documented and the torsion test results are listed in this paper. The results of this study could be useful guidelines on the development of CFRP ship shaft systems and a test method.

• 대한기계학회논문집A
• /
• 제37권2호
• /
• pp.199-204
• /
• 2013

최근 차량 경량화를 통한 에너지 절감을 위해서 무거운 철강재료를 경금속이나 복합재료로 대체하는 연구가 많이 진행되고 있다. 이중, 폴리머 기반의 복합재료는 사출성형을 통해서 복잡한 형상의 제작이 가능하고, 유리섬유나 탄소섬유를 함께 사용하여 철강재료 수준으로 기계적 물성을 높일 수 있는 장점이 있다. 하지만 엔진의 고온과 우기에서의 높은 습도 환경은 폴리머의 기계적 물성을 낮추기 때문에 재료선택 과정에서 반드시 고려해야 한다. 본 연구에서는 사출성형을 통해 만들어진 유리섬유강화플라스틱을 엔진룸 내부 온도와 유사한 $85^{\circ}C$ 환경과 우기시의 최대 수분흡수 환경하에서의 기계적 물성변화를 인장시험을 통해 알아보았다. 그 결과, 고온환경에서 최대인장강도가 약 23% 감소를 보였고, 수분에 의해서는 약 30% 감소하였으며, 고온과 수분 모두에 대해서는 약 70% 감소를 확인하였으며 이는 재료 선정시 반드시 고려해야 할 영향으로 판단되었다.

• 상하수도학회지
• /
• 제18권5호
• /
• pp.638-648
• /
• 2004

In many drinking water treatment plants, chlorination process is one of the main techniques used for the disinfection of water. This disinfecting treatment leads to the formation of haloacetic acid (HAAs). In this study, headspace solid-phase microextraction (HS-SPME) was studied as a possible alternative to liquid-liquid extraction for the analysis of HAAs in drinking water. The method involves direct derivatization of the acids to their methyl esters without methyl tert-butyl ether (MTBE) extraction, followed by HS-SPME with a $2cm-50/30{\mu}m$ divinylbenzene/carboxen/polydimethylsiloxane fiber. The effects of experimental parameters such as selection of SPME fiber, the volume of sulphuric acid and methanol, derivatization temperature and time, the addition of salts, extraction temperature and time, and desorption time on the analysis were investigated. Analytical parameters such as linearity, repeatability and limit of detection were also evaluated. The $2cm-50/30{\mu}m$-divinylbenzene/carboxen/polydimethylsiloxane fiber, sulphuric acid of 1ml, methanol of 3ml, derivatization temperature of $50^{\circ}C$ derivatization time of 2hrs, sodium chloride salt of 10g, extraction time of 30 minutes, extraction temperature of $20^{\circ}C$ and desorption time of 1 minute at $260^{\circ}C$ were selected as the optimal experimental conditions for the analysis of HAAs. The linearities ($r^2$), relative standard deviations (%RSD) and limits of detection (LOD) for HAAs were 0.9978~0.9991, 1.1~9.8% and $0.05{\sim}0.2{\mu}g/l$, respectively.

• Journal of the Korean Wood Science and Technology
• /
• 제48권6호
• /
• pp.869-877
• /
• 2020

The power consumption in the low consistency (LC) refining is an important indicator for the optimal control of the process and it is composed of the net power and the no-load power. The refining efficiency and process characterization of LC refining are directly affected by power consumption. In this paper, the effect of pulp consistency and average fiber length on the power consumption and refining efficiency were studied through the LC refining trials conducted by an experimental disc refiner. It is found that the curve of power-gap clearance can be divided into constant power section, power reduction section, and power increase section. And the no-load power and the adjustable domain of loading applied by the refining plates will increase as the increase of pulp consistency, while the increase of net power is larger than that of no-load power which makes the increasing of refining efficiency. Meanwhile, the adjustable domain of loading applied by the refining plates can be slightly improved by increasing the average fiber length, but its effect on the no-load power in the LC refining process can be neglected. The study of power consumption in LC refining is of positive significance for the proper selection of pulp properties in LC refining, in-depth exploration of refining mechanism, and energy consumption reduction in refining.

• 한국통신학회논문지
• /
• 제28권7A호
• /
• pp.433-439
• /
• 2003

본 논문에서는 광섬유 브래그 격자와 Cr/Au 박막이 단면에 증착된 광섬유를 이용하여 위상 배열 안테나를 광학적으로 구동할 수 있는 새로운 구조의 광 실시간 지연 선로를 제안하였다. 이 구조는 각 안테나 소자에 연결된 광 지연선로에서 금속 박막이 광섬유 브래그 격자 한 개를 대체하기 때문에 광섬유 브래그 격자들로만 구성된 종래의 실시간 지연선로 구조들에 비해 적은 수의 광섬유 브래그 격자를 사용하며, 금속 박막의 반사율이 광범위한 파장대역에서 일정하므로 금속 박막으로부터 반사되는 파장을 선택하기 용이한 장점을 갖고 있다. 0$^{\circ}$와 $\pm$30$^{\circ}$로 빔 주사가 가능한 10 GHz 선형 위상 배열 안테나를 위한 실시간 지연선로를 구현하였으며, 모든 빔 주사각에서 시간 지연 측정 결과는 계산치와 일치하였다. 또한, 제안된 실시간 지연선로로 구동되는 8개의 안테나 소자로 구성된 10 GHz 선형 배열 안테나를 설계하였으며, 이 안테나의 원거리 방사패턴을 시뮬레이션을 통해 구하였다.

• 한국축산식품학회지
• /
• 제35권1호
• /
• pp.101-107
• /
• 2015

The aim of this study was to investigate the effects of various marination processes on the quality characteristics of chicken breast prepared with chicken feet gelatin and wheat fiber. The chicken feet gelatin was swollen with hydrochloric solution (0.1 N HCl, pH $1.31{\pm}0.02$) and dehydrated by freeze-drying. The composition (w/w) of the marinade was water (10%), soy sauce (12%), phosphate (0.3%), wheat fiber (1.5%), and chicken feet gelatin (1.5%). Three samples of chicken breast were manufactured with Tumbler (only tumbler), Tenderizer (tenderizer and tumbler), and Injector (injector and tumbler). The water content of the Injector sample was significantly higher than those of the Tumbler and Tenderizer samples (p<0.05). During heating, the lightness of all chicken breasts increased and the redness decreased. The tumbling and cooking yield of the Injector sample were significantly higher than those of the Tumbler and Tenderizer samples (p<0.05). The shear force of the Tenderizer sample was significantly lower than that of the Tumbler and Injector samples (p<0.05). No significant differences, except for color, were observed in the sensory analysis of the samples. Thus, the proper selection of mechanical processing is important to improve the quality characteristics of marinated chicken breast, considering the types of final products.

• 대한지역사회영양학회지
• /
• 제8권1호
• /
• pp.91-101
• /
• 2003

The purpose of this study was to investigate the compliance and need for diet therapy among diabetics and their caregivers. A total of 625 respondents participated in this survey. Appropriate management for long-term blood glucose control and difficult-to-manage cases appeared to be diet therapy, physical activity, medical treatment and folk remedies, in that order. The most important educational avenues for diet therapy were books, magazines and TV, Most respondents were educated in diet therapy within a year after diagnosis and had practiced diet therapy for over four years. The most common diet therapy Practices were food selection and Quantity control. Of the specific problems in practicing diet therapy, time and labor, taste, and meal planning appeared to be equally difficult factors. The prevailing diet therapy skills were controlling food amounts at breakfast and supper, and selecting food for lunch and refreshments. Respondents practicing both skills were about 20% of the participants; this shows the need to improve the current situation. The nutrients most frequently considered in diet therapy practice were simple sugars (sugar and sweet goods) , total fats and cholesterol. Since the perception of the role of dietary fiber among respondents was very low, nutrition education about the importance of dietary fiber and food sources of dietary fiber was needed. Diabetics seemed to be concerned about diabetic menus. Three difficult problems in planning diabetic menus were daily menu planning, patient's preferences, and the calculation of calories. As a means of nutrition counseling, they preferred interviews. The higher the educational status and the lower the age, the higher the preference was for internet or PC counseling. Therefore, it is necessary to develop nutrition educational programs so that diabetics can obtain practical knowledge of diet therapy. Furthermore, it is also necessary to develop additional means of informing diabetics about menu planning, while still considering Korean dietary behavior.