• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.376-380
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• 2009

The transmission noise characteristics through the ventilating duct was conducted numerically using SYSNOISE. A ventilating system is usually composed of mufflers for preventing noise transmission from the ventilator into indoors through the ducts and distributors for transferring air to or from each room. The transmitted noise characteristics of distributors which have different branch angles and of mufflers having different shapes were analyzed numerically. New duct element combining a muffler and a T-shaped distributor was developed for better noise reduction in this paper. New element's performance was shown numerically.

• 대한치과의사협회지
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• 제4권1호
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• pp.27-30
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• 1963

The author have had a case of salivary stone in the anterior half of Wharton's duct in the left side. 1)The patient was 32-year=old Korean male .2)There was a history of severe pain at mealtime, pus discharging and marked swelling of the left submandibular region.3) The patient was sebmandibular region. 3)The paient was sedated with 100mg .of Seconal and anesthetized with 2% Xylocaine Hydrochloride. The surgical procedure was performed in the usual manner. 4)THhe stone was ellowish-white, single wheat-shaped and 9mm. by 3mm. in size.

• 대한조선학회논문집
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• 제32권1호
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• pp.83-93
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• 1995

사각형의 MHD 추진 덕트 내부유동을 수치해석과 실험적인 방법으로 연구하였다. 수치해석연구에서는 전기장과 자기장의 영향하에 있는 비압축성 3차원 통전유체에 대하여 유한 차분법으로 계산하였다. 수치계산의 결과 전자기력이 약할때 층류유동의 전형적인 포물선 유동 형태가 전극 부근에서 M자 형상으로 변하였고, 균일분포의 일정 전자기력하에서 MHD 덕트 내부 압력은 입구에서부터 하류로 나아감에 따라 선형적으로 증가하였다. 실험에서는 MHD 추진 덕트 내부 유동을 해석할 수 있는 실험장치를 제작 하였으며, MHD 추진은 전류를 변화 시킴으로써 추력을 쉽게 조정할 수 있음을 알았다. 또한 MHD 덕트내 유동방향의 압력구배는 전자기력에 비례하여 증가하며 수치계산 결과와 잘 일치하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 추계 학술논문 발표대회
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• pp.11-14
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• 2007

Noise level and Airflow amount of a kitchen hood are affected by the conditions of airflow path. Thus this study is expected to be used as a basic reference in designing airflow path of apartment housing throughout analysing changes in noise level and airflow amount from the various conditions of airflow path. Noise level generated by the kitchen hood is estimated in a kitchen and a living room of two constructed apartment houses, and an experiment is conducted in an half anechoic chamber to analyze noise level and airflow amount by the different length, diameter and number of windings of a round shaped soft duct which is connected to the kitchen hood. The measured results in apartment houses show that the noise level in both apartments exceeds the NC standard greatly in living spaces. In apartment A, a regular apartment house, the noise level was $NC-65{\sim}75$, $NC-45{\sim}60$ and NC-70, NC-45 in the kitchen and living room with an operation of kitchen hood in 1 and 3 stages. In apartment B, an apartment complex, the noise level was NC-55 and NC-60 in the kitchen and living room with an operation of kitchen hood in 3 stages. In particular, there was an increase of noise level at 125Hz-band resulted from an amplification of sound, which requires adequate measures in noise reduction. The results measured in Half anechoic chamber show 99% of airflow amount increase with the modification of a duct' s diameter from ${\Phi}$ 100mm to ${\Phi}$ 125mm, 37% of airflow amount increase with the modification of a duct' s diameter from ${\Phi}$ 125mm to ${\Phi}$ 150mm, and 173% of airflow amount increase with the modification of a duct' s diameter from ${\Phi}$ l00mm to ${\Phi}$ 150mm. The noise level was lower than the level measured in apartment housing about 20 in NC-value and 11.4 in dB(A)-value, which was interpreted as the effect of the load by the pressure condition at the rear end of the duct. Also, an amplification of sound in 125Hz-band influenced NC-value considerably, therefore effective measure is needed.

• 설비공학논문집
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• 제24권6호
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• pp.515-520
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• 2012

A daylighting system includes three parts; light collector, light transformer and light distributor. A DBLP(Double blind light pipe) daylighting system consists of a double blind light collector, a mirror duct type light transformer and a prism film light pipe distributor. The double blinds for a light collection are used to track the sun's altitude and azimuth movements throughout the day. Behind both sets of blinds is the light transformer, which is based on a rectangular cone shaped light duct. The light transformer was designed to efficiently deliver the light into the light pipe within a 30 degree radial spread for the efficient light into the distributor. In this study, DBLP system efficiency was simulated, evaluated and optimized by Tracepro as a popular ray trace light design simulation program. The results indicated that DBLP system efficiency evaluated a maximum 22.4% in case of Spring/Fall season solar noon time. While the overall average system efficiency in the morning and afternoon is evaluated about 10%.

• 대한약침학회지
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• 제11권3호
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• pp.5-16
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• 2008

Objective: We took intravascular threadlike structures from rat aortas to investigate their histological characteristics consistent with the intravascular Bonghan duct. Methods: Gomori s silver impregnation method, in addition to routine hematoxylin and eosin staining, was applied to demonstrate the characteristic feature of the intravascular threadlike structures. Results: These two staining methods clearly showed that the intravascular threadlike structures had unique features of argyrophilic reticular fibers and heavily stained oval or rod-shaped nuclei in them. Conclusion: The results are strong evidences for identifying threadlike structure as the intravascular Bonghan duct.

• Advances in aircraft and spacecraft science
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• 제1권3호
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• pp.353-378
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• 2014

This paper deals with the early development of the Anuloid, an innovative disk-shaped VTOL aircraft. The Anuloid concept is based on the following three main features: the use of a ducted fan powered by a turboshaft for the lift production to take-off and fly; the Coanda effect that is developed through the circular internal duct and the bottom portion of the aircraft to provide further lift and control capabilities; the adoption of a system of ducted fixed and swiveling radial and circumferential vanes for the anti-torque mechanism and the flight control. The early studies have been focused on the CFD analysis of the Coanda effect and of the control vanes; the flyability analysis of the aircraft in terms of static performances and static and dynamic stability; the preliminary structural design of the aircraft. The results show that the Coanda effect is stable in most of the flight phases, vertical flight has satisfactory flyability qualities, whereas horizontal flight shows dynamic instability, requiring the development of an automatic control system.

• 환경생물
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• 제33권2호
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• pp.93-97
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• 2015

The goniadid species, Glycinde bonhourei Gravier, 1904, is newly reported with the description and illustration from Korean waters. Our Korean materials of G. bonhourei have the following characteristics that are generally known as distinctive features from its congeners: the area II-1 on proboscis possesses unidentate papillae bearing broad base; the area IV on proboscis bears the papillae of duct's foot-shaped with rounded teeth; the area V on proboscis has straightly conical papillae bearing slightly bifid tip; 4-16 micrognaths are arranged on the dorsal side; all parapodia have one neuropodial presetal lobe; uniramous parapodia are present on 19-26 anterior segments. As a result of the present study, the genus Glycinde is newly reported from Korean waters.

• Applied Microscopy
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• 제19권1호
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• pp.59-69
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• 1989

Ultrastructure of the secretory portion of the small ampullate gland in the orb web spider, Nephila clavata, has been investigated using the electron microscope. The secretory portion of this gland comprise two different regions which are a S-shaped storage sac and a long, convoluted tail. By the internal textures of the secretory granules, the sac is subdivided into two regions ; the proximal region near the tail and the distal region near the duct. Commonly single layered connectives cover the basal portion of the sac epithelium, and apical portion of the epithelial cells is occupied by the thick cuticles. Within the epithelial cells of both the proximal and distal region, several types of the secretory granules surrounded by a limiting membrane and had characteristic crystalloid are scattered throughout the cytoplasm. The granular size and its electron densities are not coincide with each other according to the maturation level of the granules. The wall of the tail is composed of single layer of columnar epithelial cells, and their nuclei are found at the basal portion of the cells. Dissimilar to the epithelial cells of the sac, apical cuticles are not found at this portion. In the cytoplasm of these cells, numerous secretory granules, synthesized from the rough endoplasmic reticula commonly and had fine fibrous materials, are found. At the cell surface bordering the lumen, microvilli are seen, arid along the cellular boundaries specialized septate junctions and desmosomes appeared.

• Advances in aircraft and spacecraft science
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• 제4권4호
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• pp.401-419
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• 2017

This paper presents the main outcomes of the preliminary development of the Anuloid, an innovative disk-shaped VTOL aircraft. The Anuloid has three main features: lift is provided by a ducted fan powered by a turboshaft; control capabilities and anti-torque are due to a system of fixed and movable surfaces that are placed in the circular internal duct and the bottom portion of the aircraft; the Coanda effect is exploited to enable the control capabilities of such surfaces. In this paper, results from CFD analyses and wind tunnel tests are presented. Horizontal and vertical flights were considered, including accelerated flight. Particular attention was paid to the experimental analysis of the Coanda effect via a reduced scale 3D printed model. The results suggest that the Coanda effect is continuously present at the lower surface of the Anuloid and may be exploited for the control of the aircraft. Also, very complex 3D flows may develop around the aircraft.