• 한국전자파학회논문지
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• 제18권10호
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• pp.1189-1195
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• 2007

본 논문에서는 폴드형 GSM/DCS/USPCS 서비스용 휴대폰 단말기에 적용되는 3중 대역 폴디드 모노폴 안테나를 설계 제작한다. 안테나는 변형된 미앤더 구조이며, 접힌 형상을 갖도록 설계함으로써 GSM 주파수 대역에서는 길이를 늘리는 역할을 하고, DCS/USPCS 주파수 대역에서는 같은 방향으로 전류가 형성될 수 있도록 한다. 같은 방향의 다중 전류는 방사 저항과 이득을 동시에 높게 해 줌으로써 내장형 안테나로 성능 구현이 어려운 휴대폰에 적용될 수 있다. 설계된 안테나를 프레스 공법으로 제작하여 휴대폰에 적용한 결과 GSM/DCS/USPCS의 3중 대역에서 폴드 닫힘 상태에서 VSWR 3:1, 열림 상태에서 2:1 이내 특성을 만족하고 있으며, 최대 이득은 GSM 밴드에서 -0.02 dBi, DCS 밴드에서 +0.2 dBi, USPCS 밴드에서 +0.78 dBi을 가지고 전방향성 특성의 H면 방사 특성을 보인다.

• 한국해양바이오학회지
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• 제4권1호
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• pp.24-30
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• 2010

Species Kappaphycus alvarezii (Doty) Doty, Kappaphycus striatum (Schmitz.) Doty and Eucheuma denticulatum (N. L. Burman) Collins et Harvey, which was brought to Vietnam from Japan in 1993 and Coco island, Martan Sea, Cebu, Philippines in 2005 have been cultivated in the different coasts of South Central Vietnam. Their growth rates and physical properties of carrageenan, then, were analyzed. The obtained results showed that the growth rate of E. denticulatum and K. striatum strains is higher than those of K. alvarezii. Species of K. striatum could grow over wide range of temperature and tolerate more strongly to high temperature compared with K. alvarezii, but their content and gel strength of kappa-carrageenan were almost the same and high. For purpose of the Kappahycus cultivation farms with stable and high production all year round (especially in the seawaters of shallow, semi-closed Lagoons where the water movement is not good and with high temperature in the hot season), mixed cropping of K. alvarezii and K. striatum as seeds stock during different cropping seasons was established. Our results suggested that K. alvarezii and K. striatum could be grown in the cool season (from Oct. to next March) with the same and high content and gel strength of kappa - carrageenan, but in the hot season need to chose K. striatum for cultivation only (from Apr. to Sept.).

• 한국의류학회지
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• 제42권1호
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• pp.14-25
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• 2018

This study is to understand subculture as a selective amity or an emotional tribe that includes a life style, hobby and leisure of people and seeing it as the tribal solidarity or emotional alliance. Hence, based on the neo-tribalism by Michel Maffesoli who explains a tribe not composing a social vertical structure represented by class, but is composed a horizontal structure of individuals as a member of a society, this study conducted an empirical analysis on domestic minor fashion communities. Research findings show that they have a unique structure unexplained by Maffesoli. Fashion styles, values shared by domestic minor fashion communities are almost entirely based on individual likes and dislikes, escaping from a symbol of resistance to subordination explained by the existing subculture, play a role in enhancing the solidarity inside the community and confirming its identity outside. However, as for shared values within a community, it reveals a new invisible type of subculture intra-inter domestic minor fashion communities. A community showed a closed mind rather than open mind, disregarding or comparing with other communities and preventing their members from participation. A community had strict fashion rules and obvious classes, leading to participatory restriction. In conclusion, domestic minor fashion communities showed the most significant characteristic of a selective vertical structure by individual and community rather than a vertical structure by a society.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제13권4호
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• pp.370-380
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• 1991

This article is intended to study histopathological and immunohistochemical response after autogenous full-thickenss skin graft in rat. 12 male Sprague-Dawley rats were used as the experimental animals. A $1Cm{\times}1Cm$ skin(0.7mm diameter) was taken on the right inguinal area of the rat. Another full-thickeness skin graft($1Cm{\times}1Cm$) was taken from the left inguinal area of the rat. And it was transplanted to the right inguinal area of the rat. The left side wound was closed directly. Light microscopic observation was made at the postoperative $1^{\circ}3^{\circ}8^{\circ}16$ day, after the hematoxylin - Eosin staining of the 4u-thick paraffin embedded specimens and the immunoshitochemical staining of the 10u-thick frozen specimens with mouse anti-rat monoclone antibodies and ABC staining kit. The results were as follows. 1. Electromicroscopic studies revealed interstitial tissue bleeding of transplanted autogenous skin. The response was severe in the 1 day group after operation, moederate in 3 day group, mild in 8 day group, and almost resovled in the 16 days group. 2. Electromicrospic studied also revealed a mild monocyte response in the 3 day and 8 day group. A histiocytic infiltrate was observed. There was a mild response in the 3 day group and moderate response in the 8 day group. 3. Immunohistochmically studies revealed a few pan T cells in the 1 day group, mild appearance of pen T cells and cytotoxic T cells in the 3 day group, a moderate infiltrate of pan T cells and helper T cells in the 8 day group, and total resolution of pan T cells in the 16 day group. 4. According to these finding, a strong inflammatory response was observed around transplanted autogenous skin in the 3 & 8 day groups. In the 16 day group this response had resolved histopathologically and immunohistologically.

• 한국유체기계학회 논문집
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• 제19권2호
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• pp.5-10
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• 2016

Gas flow measurement in a closed duct was performed using multi-point Pitot tubes. Measurement uncertainty was assessed for this measurement method. The method was applied for the measurement of air flow into a gas turbine engine in an altitude engine test facility. 46 Pitot tubes, 15 total temperature Kiel probes and 9 static pressure tabs were installed in the engine inlet duct of inner diameter of 264 mm. Five tests were done in an airflow range of 2~10 kg/s. The flow was compressible and the Reynolds numbers were between 450,000 and 2,220,000. The measurement uncertainty was the highest as 6.1% for the lowest flow rate, and lowest as 0.8% for the highest flow rate. This is because the difference between the total and static pressures, which is also related to the flow velocity, becomes almost zero for low flow rate cases. It was found that this measurement method can be used only when the flow velocity is relatively high, e.g., 50 m/s. Static pressure was the most influencing parameter on the flow rate measurement uncertainty. Temperature measurement uncertainty was not very important. Measurement of boundary layer was found to be important for this type of flow rate measurement method. But measurement of flow non-uniformity was not very important provided that the non-uniformity has random behavior in the duct.

• 수산해양기술연구
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• 제24권4호
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• pp.172-179
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• 1988

A cartridge type hydraulic logic valve consists of simple two port valve whose poppet is closed or opened by means of pressure signal of a pilot line. Accordingly, the logic valve can be used not only for direction, flow and pressure control purpose but also for versatile function valve which enables all above mentioned functions. In addition, the valve has little internal leakage and pressure loss, superior response characteristics and easiness in making small block type valve. The above mentioned good performances being recognized recently, the logic valve has been used widely in the large scale hydraulic system such as a hydraulic press system, for the performance requirements of high speed operation and precise control characteristics. However, there are scarce reports until now, except for a few ones from Aachen Institute of Technology in West Germany, so it is necessary to be studied on development and investigation for practical application. This paper showed that the static and dynamic characteristics of a logic valve when the logic valve is used for directional control, to investigate the relations between the valve operating characteristics and the valve design conditions. From the above mentioned procedure, it was ascertained that the valve operation characteristics obtained by numerical analysis showed good agreements with experimental results. The representative results obtained are as follows; 1. During the valve is closing, the poppet velocity is almost constant in the logic valve. 2. The pilot pressure P sub(3) and the resistance R in the pilot line have much influences on the valve operation time. 3. Spring strength have not such a severe influence on the valve operating time. 4. The operation characteristics of the logic valve can be estimated with good accuracy comparatively by numerical analysis with the equations describing poppet motion.

• Korean Chemical Engineering Research
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• 제49권6호
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• pp.732-738
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• 2011

고압 반응시스템에서 요소와 메탄올로부터 메틸카바메이트(MC) 및 디메틸카보네이트(DMC)의 제조에 관한 금속산화물촉매와 이온성액체의 영향을 고찰하였다. 고립계에서 요소와 메탄올로부터 MC 수율은 촉매를 사용하지 않고도 $150^{\circ}C$ 이상의 반응온도에서 거의 100%를 나타내었으나, DMC 수율은 반응온도와 무관하게 1.5% 이하로 매우 낮은값을 나타내었다. 또한 MC와 메탄올로부터 DMC 수율은 $ZnCl_{2}$ 촉매를 사용한 경우에 가장 우수하였으며, 최적조건에서 16.3% 정도를 나타내었다. DMC 수율은 반연속식 실험에서 나노 크기의 촉매와 이온성액체를 함께 적용한 경우에 좀 더 향상되었다.

• 한국통신학회논문지
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• 제34권7A호
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• pp.562-567
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• 2009

본 논문에서는 여러 송수신 안테나를 갖는 송신기(source node), 중계기(relay node), 수신기(destination node)로 구성된 두 홉(two-hop) 빔포밍(beamforming) 중계 시스템을 고려한다. 송수신 심벌간 평균제곱오차(mean square error: MSE)를 최소화하는 송수신기 빔포밍 벡터와 중계기 가중치 행렬을 설계한다. 이때, 송신기 또는 중계기에 송신 전력을 줄이기 위하여, 국소(local)부동식전력제약(inequality power constraint)을 사용한다. 제약식이 있는 평균제곱오차 최소화 문제는 라그랑즈(Lagrange) 방법을 써 제약식이 없는 최적화 문제로 바꿀 수 있고, Karush-Kuhn-Tucker (KKT) 조건으로부터 그 해를 얻을 수 있다. 제안한 중계 시스템에 송신기와 중계기 송신전력을 각각 국소부동식으로 제약하여, 그 결과 두 홉에 채널 상태가 다를 경우, 최대 신호대잡음비(signal-to-noise ratio: SNR)를 얻는 기존 방식과 대등한 성능을 내며, 동시에 송신기 또는 중계기 송신 전력을 줄일 수 있다. 이를 모의실험을 통해 확인하였다.

• Animal cells and systems
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• 제9권3호
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• pp.139-144
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• 2005

The attractant (orange light) or repellent (white light) signal is transmitted from SRI (Sensory Rhodopsin I) via protein-protein interaction with its transducer Htrl (Halobacterial Transducer for Sensory Rhodopsin I) which in turn controls a cytoplasmic phospho-transfer pathway that modulates flagella motor switching in Halobacterium salinarum. Some mutations in both SRI and Htrl showed an unusual mutant phenotype called inverted signaling, in which the cell produces a repellent response to normally attractant light. Twelve mutations at the Glutamate 56 (E56) position in the second transmembrane helix of Htrl were introduced by site-specific random mutagenesis. Almost all E56 mutants showed orange-light inverted responses in pH and temperature-dependent manners except E56D and E56Y. Except for these two mutants, all mutants accelerated the $S_{373}$ decay compared to wild-type at $18^{\circ}C$. This supported that there is an interaction between SRI and the second transmembrane of Htrl. Also a structural model of Htrl based on the Tar crystal structure and the secondary structure prediction program proposed the E56 residue to be in the middle of the proton channel. The most important observation is that the E56 mutant provides the evidence that this residue is very sensitive for signal relay, which can be explained by the open and closed conformations of the channel (A and R conformations) in SRI, as was postulated by the unified conformational shuttling model for transport and signaling.

• Journal of Periodontal and Implant Science
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• 제31권2호
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• pp.389-400
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• 2001

Previous studies have demonstrated an increase in bone mass and density with the use of bisphosphonate in osteoporosis. This agent acts as an inhibitor of osteoclastic activity, and results in increase of net osteoblastic activity. Currently, it has been reported that bisphosphonate has direct effect on osteoblast. This study was designed to evaluate the effect of alendronate on bone regeneration in defect of rat calvaria. The animals used for these experiments were 48 male rats, over 6-8 weeks old. They were divided into three groups according to the dose of alendronate($MK-217^{(R)}$, Merck, USA) administered. After the calvarial defects were surgically created, the rats received a peritoneal alendronate(0.25mg/kg) in group I, a peritoneal alendronate(1.25mg/kg) in group II, and a peritoneal normal saline injection in the control group. Three and six weeks later, blood was sampled and evaluated for alkaline phosphatase activity. The animals were sacrificed for histological observation and histometric analysis of the level of bone formation. The alkaline phosphatase activity was similar in three groups at 3 weeks of experiment. The activity at 6 weeks increased more than twice, compared to 3 weeks, and was slightly higher in group I than the other two groups. In histological observation, all the groups at 3 weeks, osteoblast rimming and new bone formation were observed along the defect margin. At 6 weeks, the defect was almost closed with new and more mature bone, but new bone is thinner than original bone in the central portion of defect. In histometric analysis, group I and II at 3 weeks showed significantly greater new bone formation than the control, and all the groups at 6 weeks showed similar amount of bone formation. These result suggest that alendronate administration in the dose of 0.25mg/kg and 1.25mg/kg promote osseous regeneration.