• 대한기계학회논문집B
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• 제26권8호
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• pp.1055-1061
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• 2002

A numerical and experimental study on the flow fields behind the fan outlet was carried out to improve the performance of a conventional fan-sink(fan and heat sink). Conventional fan-sinks have a heat sink of which fin configurations tend to increase the flow resistance, thus decreasing the performance and the cooling capabilities of a fan-sink. Lifting surface method is used for the prediction of flow fields behind the fan outlet. Oil-dot flow visualization technique is applied for the validation of numerical results. The numerical results and experimental data show agreement each other. A conventional heat sink is modified and redesigned using flow patterns behind the fan outlet. The newly designed heat sink has the configuration of curved fins which minimize flow resistance. It showed improvements in both cooling: capabilities and volumetric flow rate compared to the conventional one.

• International Journal of Naval Architecture and Ocean Engineering
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• 제2권3호
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• pp.139-145
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• 2010

In the present study, we conducted resistance test, propeller open water test and self-propulsion test for a ship's resistance and propulsion performance, using computational fluid dynamics techniques, where a Reynolds-averaged Navier-Stokes equations solver was employed. For convenience of mesh generation, unstructured meshes were used in the bow and stern region of a ship, where the hull shape is formed of delicate curved surfaces. On the other hand, structured meshes were generated for the middle part of the hull and the rest of the domain, i.e., the region of relatively simple geometry. To facilitate the rotating propeller for propeller open water test and self-propulsion test, a sliding mesh technique was adopted. Free-surface effects were included by employing the volume of fluid method for multi-phase flows. The computational results were validated by comparing with the existing experimental data.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1045-1046
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• 2011

본 논문에서는 굴곡면 커버내에 전기회로를 구현시 그 동안 포토리소그라피 공정으로 제작된 PCB를 휴대기 등 내부 케이스에 부착하여 전기회로를 구현하였으나 본 논문에서는 PCB없이 직접 케이스인 복합 폴리머소재에 레이저조사에 의해 패턴과 무전해도금으로 전기회로를 직접구현하는 기술이다. 이러한 방법은 제안한 3단계 공정기법에 의해 가능하며, 즉 사출형 복합폴리머소재제작, 소재의 레이저조사에 의한 시드패턴 구현 및 형성시드의 무전해도금에 의한 전도성패턴구현 공정을 통하여 곡면커버의 전기회로구현이 가능하다. 이에 따라 기존의 복잡한 10 단계 이상의 포토리소그라피 공정을 레이저조사에 의한 3단계 공정으로 간소화함으로서 제품의 생산성향상, 다량장비 구입절감, 작업공간축소 및 기타 소재절감 등의 경제적 효과를 얻을 수 있다. 응용분야는 2차원 평면 전기회로 외에 3차원 곡면형상의 제품인 자동차, 휴대폰, 의료기, 센서, 오토바이 등의 커버에 직접회로 응용이 가능하다. 이에 대한 타당성은 실험결과를 통하여 입증하였다.

• Natural Product Sciences
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• 제17권1호
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• pp.45-50
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• 2011

Sophisticated modern research tools for evaluation of medicinal plants are available but microscopic methods are one of the simplest and cheapest methods to establish the identity of the source materials. Pharmacognostical investigation of the dried, powdered and anatomical sections of the fruits of Trachyspermum roxburghianum (DC) Craib was carried out to determine its macro and microscopical characteristics along with its physical constants. Externally, the fruits, yellowish or greenish brown in colour are elongated, elliptical, slightly curved, prominently ridged and longitudinal. As seen in transectional views of the fruits from Trachyspermum roxburghianum, the mericarp has concave sides called commissural surfaces and a convex outer side called the dorsal surface. The mericarp has three primary ridges alternating with two secondary ridges on the dorsal side. On the commissural side, there are two primary ridges which are lateral in position and two secondary ridges in the commissural side. The seed is attached to the pericarp by a short stalk called a raphe. Circular, four-lobed calcium oxalate crystals are fairly abundant in the endosperm. Phytochemical studies revealed the presence of phenolic compounds, triterpenoids, proteins and sugars. The pharmacognostical profile of the fruits will assist in standardization for quality, purity and sample identification.

• 한국기계가공학회지
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• 제12권3호
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• pp.21-27
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• 2013

This study is investigated on flow analysis according to grill configuration of radiator. The stream of flow which pass through radiator grill in car body and the contour of pressure distribution are estimated by the basis. As the magnitude of resistance force which flow affects the car body is investigated so that the power reduction can be reduced. As the pressure inside radiator grill is assessed, more efficiency can be investigated in order that the flow rate inside car body can be increased. Model 2 has the most air resistance and model 1 has the least among model 1, 2 and 3. Model 1 has the most air flow rate at inside. There are model 3 and 2 simulated according to flow rate. As the curved surface at radiator grill configuration increases in number, air flow rate becomes distributed uniformly. By considering the effect on air resistance and air flow rate at radiator grill, model 3 becomes the most effective configuration.

• 식물병연구
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• 제19권4호
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• pp.308-312
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• 2013

The popcorn disease caused by sclerotia forming fungi reduces the productivity of mulberry fruits in world wide. In Korea, only two species (Ciboria shiraiana and Scleromitrula shiraiana) have been reported as the major causal organisms and their morphological features are also largely unknown. Hereby, we report the first identification of another species (i.e. Ciboria carunculoides) in Korea and detailed features of their anamorphic stage. Fungi dominantly associated with sclerotia were purely isolated from infected mulberry fruits under the microscope. PCR-amplified DNA encoding 5.8S rRNA displayed 100% similarity to Ciboria carunculoides. The anamorphic features exhibited the absence of true mycelia. Instead, very short, aseptated, branched conidiophores were directly emerged from sclerotia. Phialides were usually three in number from each conidiophore, ampuliform to navicular in shape, slightly curved and tapering towards the apex. Conidia were produced from phialides and mostly found as one celled, pear shaped, not hyaline with smooth to uneven surface walled. Diversely modified features in phialides formed pseudo-mycelial structures around the host tissue. Combined all, current study is the first report of C. carunculoides isolated in Korea and the foremost detailed description of its anamorph stage.

• 로봇학회논문지
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• 제10권3호
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• pp.146-153
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• 2015

In order to contain as much information as possible in a single image, a wide FOV(Field-Of-View) imaging system is required. The catadioptric imaging system with hyperbolic cylinder mirror can acquire over 180 degree horizontal FOV realtime panorama image by using a conventional camera. Because the hyperbolic cylinder mirror has a curved surface in horizontal axis, the original image acquired from the imaging system has the geometrical distortion, which requires the image processing algorithm for reconstruction. In this paper, the image reconstruction algorithms for two cases are studied: (1) to obtain an image with uniform angular resolution and (2) to obtain horizontally rectilinear image. The image acquisition model of the hyperbolic cylinder mirror imaging system is analyzed by the geometrical optics and the image reconstruction algorithms are proposed based on the image acquisition model. To show the validity of the proposed algorithms, experiments are carried out and presented in this paper. The experimental results show that the reconstructed images have a uniform angular resolution and a rectilinear form in horizontal axis, which are natural to human.

• 한국멀티미디어학회논문지
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• 제13권2호
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• pp.196-204
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• 2010

본 논문에서는 핸드폰 조립 전의 키패드의 개별버튼에 불량 검사방법을 제안한다. 제안한 알고리즘은 키패드의 영역 분할, 폰트 영역 분할, 이동 및 회전의 처리과정을 통해, 동일 색상의 검사 및 등급 분류, 폰트 검사, 스크래치 검사로 이루어져 있다. 특히, 본 논문에서 제안한 영역분할 방법은 기존의 단순 문턱치를 기반으로 키패드의 경사나 곡면 모양에 기인한 휘도 변화에 대응하기 위해, 패드 영역만을 B-spline으로 근사화하여, 각 화소마다 다른 표면 문턱치를 적용하는 방법을 제시한다. 또한, 키패드의 회전 정보를 고유치 및 고유벡터를 사용하여 매우 빠르고 효율적으로 구하는 방법을 제시한다. 실험결과 제안한 방법은 실제 인라인 공정상에 적용하여 실험결과 우수한 성능을 보여준다.

• 한국주조공학회지
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• 제29권1호
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• pp.33-37
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• 2009

Cartesian grid system has mainly been used in the casting simulation even though it does not nicely represent sloped and curved surfaces. These distorted boundaries cause several problems. A special treatment is necessary to clear these problems. In this paper, we propose a new method that can consider the cutting cells which are cut by casting and mold based on the partial cell treatment (PCT). This method provides a better representation of geometry surface and will be used in the computation of velocities that are defined on the cell boundaries in the Cartesian grid system. Various test examples for several casting process were computed and validated. The analysis results of more accurate fluid flow pattern and less momentum loss owing to the stepped boundaries in the Cartesian grid system were confirmed. By using the cut cell method, performance of computation gets better because of reducing the whole number of meshes.

• 한국임상수의학회지
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• 제16권2호
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• pp.409-412
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• 1999

To establish the electroacupuncture anesthesia for pigs, 6 piglets (Landrace mixed, 1 month old, 3.7~5.3 kg, female: 3 heads and male: 3 heads) were examined. The acupoints used for porcine electroacupuncture anesthesia were An-shen, and Tian-ping and Bai-hui. After horizontal insertion of needle to left and right An-shen, and perpendicular insertion to Tian-ping and Bai-hui, respectively, positive electrode was connected at right An-shen and Tian-ping, and negative electrode was connected at left An-shen and Bai-hui using veterinary electroacupuncture anesthesia apparatus, respectively. Electric condition was 3 V and 30 Hz. To examine the effect of electroacupuncture anesthesia, laparotomy (4 heads) and castration (2 heads)were applied. The induction time of electroacupuncture anesthesia was very rapid and about 1 minute, and pain of the body surface including the extremities was not detected. As for the reactions with electroacupuncture anesthesia, the head was directed to backward, nasal part was curved to one side, and blepharum was closed in part of changed nasal part. In addition, consciousness was vivid, and muscle tension and lift of the tail were observed in early stage but was relaxated afterwards. The pain was not found during incision and suture, bleeding was comparatively small volume and the class of anesthesia effect was excellent.