• 설비공학논문집
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• 제19권12호
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• pp.874-882
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• 2007

The effects of a guide fin blade on the flow characteristics in a ventilating axial fan were investigated experimentally. The guide fins were setup onto the pressure surface of the blade, and their effects on the flowrate were evaluated. Two types of the guide fin blade were designed. One is the stem fin blade, and the other is the radial fin blade. The stem fin is designed normal to the circumference of a circle, and the radial fin is designed along the circumference of a circle. The results from the guide fin blade fans are compared with that of the blade without guide fins. The position and the geometry of the radial fin setting up on the blade have an effect on the increase of flowrate with the minor sacrifice of rotational speed of the blades. The radial fin positioning at 0.84 times blade diameter shows highest performance in the flowrate. The increase of the blade weight resulting from applying the guide fins shows minor effect on the variation of rotational speed of the blades.

• Clinics in Shoulder and Elbow
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• 제21권2호
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• pp.105-110
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• 2018

Since the introduction of shoulder arthroplasty by Neer in 1974, the design of not only the glenoid component but also the humeral component used in shoulder arthroplasty has continually evolved. Changes to the design of the humeral component include a gradually disappearing proximal fin; diversified surface finishes (such as smooth, grit-blasted, and porous coating); a more contoured stem from the originally straight and cylindrical shape; and the use of press-fit uncemented fixation as opposed to cemented fixation. Despite the evolution of the humeral component for shoulder arthroplasty, however, stem-related complications are not uncommon. Examples of stem-related complications include intraoperative humeral fractures, stem loosening, periprosthetic fractures, and stress shielding. These become much more common in revision arthroplasty, where patients are associated with further complications such as surgical difficulty in extracting the humeral component, proximal metaphyseal bone loss due to stress shielding, intraoperative humeral shaft fractures, and incomplete cement removal. Physicians have made many attempts to reduce these complications by shortening the stem of the humeral component. In this review, we will discuss some of the limitations of long-stem humeral components, the feasibility of replacing them with short-stem humeral components, and the clinical outcomes associated with short-stemmed humeral components in shoulder arthroplasty.

• 한국전산유체공학회지
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• 제21권3호
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• pp.98-109
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• 2016

The flow and heat transfer characteristics of a heat exchanger having rectangular pin-fin in the flow direction have been investigated numerically. On the bottom plate, the convective boundary conditions for the hot side was given, and the fins were arranged in a channel-type geometric model using the periodic boundary condition in the span-wise direction. Three-dimensional numerical calculations for the flow and conjugate heat transfer problem were conducted using SIMPLE algorithm and $k-{\varepsilon}$ turbulence model. For the slanted pin-fin models, it was found that the downward cooling flow is generated due to the downward pressure gradient component, which can enhance the heat transfer performance near the bottom surface and the fin stem region. Four different inclined angles were considered in the Reynolds number range of 13,500-55,000. The aero-thermal performance of the slanted pin-fin heat exchangers, such as the volume and area goodness factors, were summarized and compared with the baseline plate-fin type heat exchanger quantitatively.

• 대한조선학회논문집
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• 제56권6호
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• pp.550-558
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• 2019

The roll motion of a general vessel, which is more influenced by resonance as compared to other motions, adversely affects the passenger and hull. Therefore, reducing the roll motion through an anti-rolling system is critical, and most ships use various devices such as anti-rolling tanks, bilge keels, and fin stabilizers to accomplish this. In this study, a simplified model is developed for the application of an anti-rolling device for unmanned semi-submersible vessels. The applied anti-rolling device is installed on the stern and stem of a ship using a pair of servo motors with added weight, and the motor is controlled through the Arduino. The moment of the motor is designed and implemented based on a mathematical model such that it is calculated through the restoring force according to the heel angle of the ship. The performance of the proposed system was verified by utilizing the roll damping coefficient calculated by the free-roll decay test and logarithmic decrement method and was validated by a towing tank test. The system is expected to be used for unmanned vessels to perform sustainable missions.

• 한국발생생물학회지:발생과생식
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• 제21권4호
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• pp.399-406
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• 2017

This study was conducted to investigate egg development and larvae morphological development of catfish and to provide basic data to clarify the genetic relationship with Siluriformes fish. The mother fish that was used in this study was caught in the stream of Nakdong River in Uiseong-gun, Gyeongbuk. The temperature range of the breeding was $23.0-25.0^{\circ}C$ (mean $24.0{\pm}1.0^{\circ}C$) and egg size was 1.62-1.70 mm (mean $1.66{\pm}0.05$, n=30). Eggs of catfish began hatching at 54 hours and 40 minutes after fertilization. Immediately after hatching, the total length of larvae was 3.60-3.65 mm (mean $3.62{\pm}0.03$, n=5) and had an egg yolk without swimming ability. On the third day after hatching, the larvae at the medium stage was 8.00-8.65 mm (mean $8.32{\pm}0.45$) in total length, and two pairs of whiskers formed around the mouth were elongated. On the 12th day after hatching, the larvae at the juvenile stage was 16.5-17.0 mm (mean $16.7{\pm}0.35$) in total length, and the stem of each fin was in the range, and the juvenile at this period was morphologically similar to the mother fish.

• Parasites, Hosts and Diseases
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• 제36권1호
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• pp.1-6
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• 1998

한국산 담수 패류에서 새인두홉충의 제1중간숙주를 밝히기 위해 경상북도 의성군 소재 가음지에 서 Lyrimaeidae과에 속하는 두 종류의 담수패류 물달팽이 (Ranix auiculiaria coreana) 및 애기물 달팽이 (Awpopeplea ollula)를 채집하여 조사하였다. 물달팽이 1.273개 중 12개에서 새인두흡충 유미유충이 유출되었다. 새인두흡충 유미유충은 brevifurcate이고, clinostomatoid 하였으며, 투명 한 dorsalan, 체전단에 잘 발달된 침입기구, 그리고 체중1부에 한쌍의 안점을 가지곤 있었다. 몸의 크기는 $119-147{\;}{\times}{\;}33-36{\mu\textrm{m}}$였고, tailstem은 $275-370{\;}{\times}{\;}19-26{\;}{\mu\textrm{m}}$, 그리고 furcae는 $72-104{\;}{\mu\textrm{m}}$였다. 새인두흡충 유충에 감염된 물달팽이를 파각하여 redia를 확인하였으며, 그 크기는 $527-1,630{\;}{\times}{\;}121-368{\;}{\mu\textrm{m}}$였고, 안에 10-45개의 germ ball과 다양한 발육상태의 유미유충을 가지고 있었다. 새인두흡충 유미유충을 실험적으로 감염시킨 참붕어에서 얻은 피낭유충은 자연 감염 에 의한 피낭유충과 동일한 형태학적 특징을 나타내었다.

• 대한한의학방제학회지
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• 제27권2호
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• pp.101-120
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• 2019

PURPOSE : Euonymi Lignum Suberalatum (EL) is the stem fin of Euonymi alatus. In traditional Korean medicine, EL is used for treatment of uterine bleeding, metritis and static blood. Recently, many studies have reported several pharmacological effects of EL including anticancer, antimicrobial, antidiabetic activity, and anti-oxidative stress. However, the mechanisms underlying anti-inflammatory effects by the EL is not established. METHODS : To investigate anti-inflammatory effects of Euonymi Lignum Suberalatum Water (ELWE), Raw 264.7 cells were pre-treated with $10-300{\mu}g/mL$ of ELWE, and then exposed to $1{\mu}g/mL$ of LPS. Levels of NO, IL-6, $IL-1{\beta}$ and $TNF-{\alpha}$ were detected by ELISA kit. Expression of pro-inflammatory proteins were determined by immunoblot analysis. To evaluate the anti-inflammatory effect in vivo, rat paw edema volume, and expressions of COX-2 and iNOS proteins in carrageenan (CA)-induced rat paw edema model. RESULTS : NO production activated by LPS, was decreased by $30-300{\mu}g/mL$ of ELWE. Production of inflammatory mediators such as $TNF-{\alpha}$, ILs, $PGE_2$ were decreased by ELWE 100 and $300{\mu}g/mL$. In addition, ELWE reduced LPS-mediated iNOS and COX-2 expression. Moreover, ELWE increased $I-{\kappa}B{\alpha}$ expression in cytoplasm and decreased $NF-{\kappa}B$ expression in nucleus. In vivo study, ELWE reduced the increases of paw swelling, and expression of iNOS and COX-2 proteins in paw edema induced by CA injection. CONCLUSION : The results indicate that ELWE could inhibit the acute inflammatory response, via modulation of $NF-{\kappa}B$ activation. Furthermore, inhibition of rat paw edema induced by CA is considered as clear evidence that ELWE may be a useful source to treat acute inflammation.