• Structural Engineering and Mechanics
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• 제17권3_4호
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• pp.347-356
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• 2004

In order to extend the lifetime of buildings and civil infrastructure, patch type fibrous composite retrofitting materials are widely used. Retrofitted concrete columns and beams gain stiffness and strength, but lose toughness and show brittle failure. Usually, the cracks in concrete structures are visible to the naked eye and the status of the structure in the life cycle is estimated through visual inspections. After retrofitting of the structure, crack visibility is blocked by retrofitted composite materials. Therefore, structural monitoring after retrofitting is indispensable and self diagnosis method with optical fiber sensors is very useful. In this paper, we try to detect the peel out effect and find the strain difference between the main structure and retrofitting patch material when they separate from each other. In the experiment, two fiber optic Bragg grating sensors are applied to the main concrete structure and the patching material separately at the same position. The sensors show coincident behaviors at the initial loading, but different behaviors after a certain load. The test results show the possibility of optical fiber sensor monitoring of beam structures retrofitted by the composite patches.

• Smart Structures and Systems
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• 제14권3호
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• pp.347-365
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• 2014

The main objective of this paper is to develop an innovative methodology for the vibration suppression control of the multiple degrees-of-freedom (MDOF) flexible structure. The proposed structure represented in this research as a clamped-free-free-free truss type plate is rotated by motors. The controller has two loops for tracking and vibration suppression. In addition to stabilizing the actual system, the proposed feedback control is based on a genetic algorithm (GA) to seek the primary optimal control gain for tracking and stabilization purposes. Moreover, input shaping is introduced for the control scheme that limits motion-induced elastic vibration by shaping the reference command. Experimental results are presented, demonstrating that, in the control loop, roll and yaw angles track control and elastic mode stabilization. It was also demonstrated that combining the input shaper with the proportional-integral-derivative (PID) feedback method has been shown to yield improved performance in controlling the flexible structure system. The broad range of problems discussed in this research is valuable in civil, mechanical, and aerospace engineering for flexible structures with MDOM motion.

• Journal of Welding and Joining
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• 제8권4호
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• pp.27-34
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• 1990

Integranular corrosion behaviors of KAL (Knife Line Attack) and mechanical properties such as tensile and creep rupture were investigated for the tube material used for nearly 20 years under the condition of 463.deg. C and 28 $kg/cm^2$. Based and weld metal were austenitic stainless steel AISI 321 containing Ti, AISI 347 containing Nb, respectively. KLA is a kind of the intergranular corrosion which often occurs just near the HAZ (heat affected zone) of AISI 321 and AISI 347 stainless steel due to the grain boundary sensitization. In KLA zone, intergranular corrosion crack has propagated outwards from the inner surface and carbides of white and narrow band type assuming as (Cr, Fe) carbide were confirmed. All the delta-ferrite formed in the weld metal during weld solidification has been transformed into sigma-phase since delta-ferrte was exposed for 20 years at 463.deg. C. Elongation was very low at the range from room temperature to 600.deg. C and it was confirmed that creep-rupture properties were not consideralbly affected.

• 한국의류산업학회지
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• 제14권3호
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• pp.347-362
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• 2012

The analysis results of the characteristics of children's clothes for school girls from the 2006S/S-2010S/S collections reveal that the most frequent type of item composition was 2'PS & 3'PS. T-shirts were the popular kind of item for upper garments and pants for lower garments. The major silhouettes were H and A line. The predominant neckline was U, which was followed by camisole and V. The major collar styles were stand-up and flat. Chromatic colors were used more than achromatic ones and after white the most popular colors were blue, pink, red, black, navy, and green. The dominant color scheme was a two-color or three-color scheme. The percentage of solid and patterned material garments was the highest and the most popular pattern was flowers. The most popular style of garment had no decorative detail that was followed by one-item, two-item, and three-item decoration. The major kinds of decorative detail were frills, pleats, and prints.

• 한국환경과학회지
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• 제16권3호
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• pp.347-355
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• 2007

In this paper, estimation of the compressive strength of the concrete incorporating blast furnace slag subjected to high temperature was discussed. Ordinary Portland cement and blast furnace slag cement (BSC;30% of blast furnace slag) were used, respectively. Water to binder ratio ranging from 30% to 60% and curing temperature ranging from $20^{\circ}C{\sim}65^{\circ}C$ were also chosen for the experimental parameters, respectively. At the high temperature, BSC had higher strength development at early age than OPC concrete and it kept its high strength development at later age due to accelerated latent hydration reaction subjected to high temperature. For the strength estimation, the Logistic model based on maturity equation and the Carino model based on equivalent age were applied to verify the availability of estimation model. It was found that fair agreements between calculated values and measured values were obtained evaluating compressive strength with logistic curve. The application of logistic model at high temperature had remarkable deviations in the same maturity. Whereas, the application of Carino model showed good agreements between calculated values and measured ones regardless of type of cement and W/B. However, some correction factors should be considered to enhance the accuracy of strength estimation of concrete.

• 한국연초학회지
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• 제16권1호
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• pp.69-75
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• 1994

A new flue - cured tobacco variety KF113 was developed by Nicotiana africana method from a cross of NC82 and Coker 347 at the Suwon Experiment Station. It was tested in the 0fficial Variety Test in 1991-1992 and the flue - cured Regional Farm Test in 1992. KFl13 flowers 4 days later than WC82 (standard variety in Korea) and its harvestable leaves are 2 more than those of NC82. The leaf type and shape of KFl13 resembles Coker 347. It has high resistance to bacterial wilt (Pseudomonas solanacearum) and black shank (Phytophthora parasitica var. nicotianae), and is susceptible to tobacco mosaic virus. It should adapt well to the flue - cured production area and can reduce premature flowering under unfavorable weather conditions. Yield of KFl13 is 5% higher than that of NC82, and nearly equal in value per kg compare with NC82. This variety met acceptable standards for chemical and physical characteristics of cured leaf and for smoking taste evaluated by panel members in Korea Ginseng & Tobacco Research Institute.

• BMB Reports
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• 제45권6호
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• pp.342-347
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• 2012

Plant mitochondria possess alternative respiratory pathways mediated by the type II NAD(P)H dehydrogenases and alternative oxidases. Here, E3 SUMO ligase was shown to regulate alternative respiratory pathways and to participate in the maintenance of carbon and nitrogen balance in Arabidopsis. The transcript abundance of the type II NAD(P)H dehydrogenases NDA2 and NDB2 and alternative oxidases AOX1a and AOX1d genes was low in siz1-2 mutants compared to that in wild-type. The addition of nitrate or ammonium resulted in a decrease or an increase in the expression of the same gene families, respectively, in both wild-type and siz1-2 mutants. The amount of free sugar (glucose, fructose and sucrose) was lower in siz1-2 mutants than that in wild-type. These results indicate that low nitrate reductase activity due to the AtSIZ1 mutation is correlated with an overall decrease in alternative respiration and with a low carbohydrate content to maintain the carbon to nitrogen ratio in siz1-2 mutants.

• 대한치과보철학회지
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• 제51권4호
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• pp.347-352
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• 2013

혀는 정확한 근신경계의 조화에 의해 저작, 연하, 발음과 같은 복잡한 기능을 수행하는 데 중요한 역할을 한다. 악성종양으로 인해 구강 내 혀를 절제해야 하는 경우에 환자는 발음 및 연하에 큰 어려움을 겪게 된다. 이러한 환자에 있어 보철적 치료 목표는 저작, 연하 및 발음을 증진시키는 것이다. 보철적 수복 방법은 수술의 종류 및 범위에 의해 결정된다. 완전 혀 절제술(Total glossectomy)을 시행한 경우에는 하악-혀장치(mandibular tongue prosthesis)를 선택하며 악-혀장치(Mandibular tongue prosthesis)는 혀 보철물로 구강저를 채우는 것이다. 이렇게 형성한 혀 보철물은 음식이 식도로 넘어가는 입구(platform)를 형성해주고 발음을 향상시키며 하방의 연약한 이식 조직을 보호하고 외형 및 심리사회적으로 우수하다는 장점을 가진다. 본 증례에서는 완전 혀 절제술(total glossectomy)를 시행한 환자를 위해 보철적으로 수복하는 임상과정을 논의하고자 한다.

• 한국재난정보학회 논문집
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• 제16권3호
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• pp.472-478
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• 2020

연구목적: 적산온도를 이용하여 시멘트 종류별로 고강도 콘크리트(70MPa)의 초기 강도를 정확히 예측하여 콘크리트 품질의 신뢰성 확보, 거푸집 탈형 시기, PS 콘크리트의 텐셔닝 타임, 도로 보수 후 교통의 진입 시기 등을 정확히 도출하여 경제적이고 안전한 건설공사에 도움을 주고자 한다. 연구방법:시멘트 종류별 수화열을 재령마다 측정하여 적산온도를 계산하고, 재령별 콘크리트의 강도를 측정하여 임의의 적산온도에 상응하는 강도를 예측한다. 연구결과: 도로보수에서 교통개방에 필요한 시간을 추정하는데 있어서, ASTM C1074에서는 고강도 콘크리트의 경우에는 이론적으로 16.4시간으로 예측하였으나, 본 연구에서는 OPC인 경우의 적산온도 307, 14.4 시간, LHPC인 경우의 적산온도 2700, 34시간, ESPC인 경우의 적산온도 200, 8시간 정도로 계산되었다. 결론:고강도 콘크리트를 사용한 구조물의 거푸집 탈형시기 및 도로보수의 교통개방 시기는, ACI Committee 347을 적용한 설계기준강도 40MPa이하의 보통콘크리트의 경우보다 월등히 빨라질 수 있다.

• 한국수산과학회지
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• 제10권4호
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• pp.237-241
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• 1977

1976년 9월 20일 부터 24일 사이에 북서태평양(Kamchatka 근해에서 투명도, 태양광선의 적색광(과장 : 600\~620\;nm)에 대한 표면조도 및 수심별 수중조도와 태양고도, 기온 및 표층수온 등을 조사한 결과를 요약하면 다음과 같다. 1. 본 조사해역의 평균투명도는 $10.6m(9\~l2m)\$로 나타났다. 2. 태양광선의 적색광에 대한 해수의 흡수계수는 $0.178\~0.376$(평균 0.278)였다. 3. 적색광에 대한 해수의 흡수계수 m와 투명도 D와의 관계는 m=3.347/D로 나타났다. 4. 관측된 평균기온은 $9.49^{\circ}C(7.8-12.6^{\circ}C)$ 였고, 평균표층수온은 $6.58^{\circ}(5.8-7.6^{\circ}C$)로 나타났다. 5. m층에서 적색광에 대한 수중투과율은 수심 5 m층에서 표면창의 $6.45\~23.5\%$(평균 $16.36\%$), 수심 10 m층에서는 $1.38\~7.31포$(평균 $3.65\%$)였고, 수심 20 m층에서는 $0.048\~0.647\% $(평균 0.276\%)로 나타났다.