• 대한조선학회지
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• 제23권1호
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• pp.13-22
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• 1986

Axisymmetric turbulent thick boundary layers on a rotating body of revolution are calculated numerically in the paper. Richardson number is introduced to the mixing length to take account of swirl effects on Reynolds stresses. Interactions of the boundary layer and the external potential flow are included by adding the displacement thickness of boundary layers on the original body. Pressure distributions on the body surface are estimated by integrating normal momentum equation across the boundary layer. A model is designed and tested in the wind tunnel. Mean velocities are measured. Through the present study, swirl effects on the thick axisymmetric boundary layer development are considerable in comparison with those of non-totating cases. Rotational motion generally increase boundary layer thickness, axial skin friction coefficients, and form drags. Circumferential flow can be reversed to induce negative skin friction when the section area is reduced.

• 보존과학회지
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• 제38권4호
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• pp.334-346
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• 2022

The manufacturing technique was studied through the structure and material characteristics of the walls and the painting layers of the Avalokitesvara Bodhisattva mural of Geungnakjeon Hall, Daewonsa Temple. The mural is painted and connected to the earthen wall and the Junggit, and the wall is composed of wooden laths as a frame, the first and middle layers, the finishing layer, and the painting layer. The first layer, middle layer, and finishing layer constituting the wall were made by mixing weathered soil and sand. It was confirmed that the first layer had a high content of loess below silt, and the finishing layer had a high content of fine-sand and very fine sand. For the painting layer, a ground layer was prepared using soil-based mineral pigments, and lead white, white clay, atacamite, minium, and cinnabar (or vermilion) pigments were used on top of it. The Avalokitesvara Bodhisattva mural was confirmed to belong to a category similar to the soil-made buddhist mural paintings of Joseon Dynasty. However, it shows characteristics such as a high content of fine sand in the finishing layer and overlapping over other colors. Such material and structural characteristics can constitute important information for future mural conservation status diagnoses and conservation treatment plans.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2000년도 특별강연 및 추계학술발표대회 개요집
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• pp.256-259
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• 2000

High viscosity mixing powder is a very useful material for laser cladding. This material has a high viscosity so that it can be sticked to substrate. Therefore, Laser cladding can be performed on a curved or slope surface. Laser cladding can be easily performed with the material instead of wire that is difficult to be manufactured in some case. In this experiment, it was used a high viscosity mixing powder which consists of a high temperature flux and a bronze powder. And AC2B alloy material was used as a substrate. Flux prevents the clad layer from being oxidized and increases bonding property between substrate and cladding material. It makes possible to laser cladding at low level energy.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.3-8
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• 2009

Wall flush mounted injector with various orifice shape and injection conditions, were examined to enhance jet penetration and mixing in supersonic cross flow, in view of application to air-breathing accelerator vehicle. Orifice shapes with high aspect ratio were found to preferable for better penetration in the cold flow, and in the reacting flow for scramjet-mode combustion conditions. However, the effectiveness of the high aspect ratio was diminished in the dual-mode combustion conditions. Supersonic injection was applied to the high aspect ratio orifice, and further increase in penetration was observed in the cold and reactive flow for scramjet-mode combustion conditions, however, mixing enhancement due to mixing layer / pseudo-shock wave system interaction was dominant in the dual-mode combustion conditions. Difficulty in attaining ignition in the case with the high aspect ratio orifice was encountered during the combustion tests.

• 한국해양학회지
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• 제25권3호
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• pp.151-159
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• 1990

조류에 의한 해수의 혼합이 활발한 연안역에서 동물 플랑크톤이 주야 수직 이동의 능력이 있는지를 파악하기 위하여 채집량의 주야 차이를 살펴 보았다. 상대적으로 크 기가 큰 요각류, Mysid, 모약류, 이매폐 유생 등은 야간에 표층에서 많이 채집되어 주 야 수직이동이 있을 가능성을 시사하고 있었다. 본 연구 결과와 과거의 방법 등을 통 하여 한국 서해 연안역에서 적절한 채집방법에 대하여 살펴 보았다.

• 한국해양바이오학회지
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• 제6권2호
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• pp.53-61
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• 2014

This study was investigated the antimicrobial activity of glutaraldehyde cross-linked glucosamine. Glutaraldehyde was used as a cross-linker which specifically combines an amine-group of molecules. To optimize the mixing ratio of glutaraldehyde and glucosamine, mixing ratio was set up 1:1, 2:1, 3:1 and 0.5:1 in molarity, respectively. The optimum mixing ratio of glucosamine and glutaraldehyde was found to be 3:1 using thin layer chromatography based on the production of complex. Glucosamine-glutaraldehyde cross-linked complex (Ggcc) revealed significant antimicrobial activity toward PWG than F1, both microbial strains were isolated from porcine semen as antibiotics resistance bacteria (ARB). These results clearly demonstrate that Ggcc has potential bactericidal activity toward ARB in porcine semen.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(2)
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• pp.25-28
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• 2002

We have been fabricated white organic light emitting diode with two-wavelength ard mixing blue emit in DPVBi (4, 4-bis(2, 2-diphenylvinyl)-1, 1 -biphenyl)layer and yellow emit in rubrene (5, 6, 11, 12-tetraphenylnaphthacene)as emitting layer which are controlled with thickness. This device emits white light emitting in CIE (0.29, 0.33), 1000cd/$m^2$ at DC 18V.

• 대한기계학회논문집
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• 제7권3호
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• pp.278-285
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• 1983

The momentum transfer in axisymmetric turbulent boundary layer over a rotating cone submerged in a free stream was studied by experiments and numerical analysis. In numerical analysis the velocity profiles were calculated by finite difference method using Prandtl mixing length concept, and the results were compared with experimental results. The agreement was good. By the numerical analysis the wall fircition coefficient was increased as the Reynolds number increased when the rotational speed is large, but the wall friction coefficient was decreased as the rotational speed increased.

• 수산해양기술연구
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• 제29권1호
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• pp.1-10
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• 1993

In order to investigate the environmental properties of set net grounds located in the coastal waters of Yeosu, oceanographic observations on the fishing grounds were carried out by the training ship of Yeosu Fisheries University from Jun. 1988 to Dec. 1990. The resultes obtained are summarized as follows; 1) The water mass in the fishing grounds were divided into the inner water (29.50-31.00$\textperthousand$), the mixed water (31.10-32.70$\textperthousand$) and the offshore water (32.70-34.30$\textperthousand$) according to the distribution of salinity from T-S diagram plotted all salinity data observed from Jun. 1988 to Dec. 1990. In spring the mixing water prevailed and in summer the inner and mixing water. But in autumn and winter the mixing and offshore waters prevailed. 2) The inner water which was formed by land water from the river of Somjin and the precipitation in the Yeosu district flowed southerly along the coast of Dolsando and spread south-easterly in the vicinity of Kumodo. The inner water and offshore water which supplied from the vicinity of Sorido and Yokchido formed the thermal front and halofront. 3) As the mixing water flowing from the western sea of Cheju to the southern coast of korea was low in temperature, the water mass of low temperature which appeared at the offshore bottom of Sorido in summer was considered not to be the Tsushima warm current. 4) As vertical mixing was made frequently in spring, autumn and winter, the differences in temperature and salinity between surface and bottom was respectively small. In summer, however, the mixing was not made because of the inner water expanded offshore through the space between surface and 10m layer and so a thermocline of $2.0^{\circ}C$/10m and halocline of 4.0$\textperthousand$/10m respectively in vertical gradient was formed. 5) In the vicinity of Dolsando and Kum a water low in salinity prevailed, but in the vicinity of Namhaedo and YoKchido the reverse took place. The inner and mixing waters formed at these arease was limited to the observation area not to spread widely.

• 한국수소및신에너지학회논문집
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• 제29권5호
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• pp.523-529
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• 2018

Two liquids which are generally used as fuels of rockets are mixed and their mixing process is quantitatively investigated by the use of particle image velocimetry (PIV). As working fluids for the liquid mixing, Dimethylfuran (DMF) and JetA1 oils have been used. Since the specific gravity of DMF is larger than that of JetA1 oil, the DMF oil has been set at the lower part of the JetA1 oil. For better visualization of the mixing process, Rhodamin B powder has been blended into the DMF oil. An agitator having 3 blades has been used for mixing the two liquids. For quantitative visualization, a LCD monitor has been used as a light source. A color camera, camcoder, has been used for recording the mixing process. The images captured by the camcoder have been digitized into three color components, R, G, and B. The color intensities of R, G, and B have been used as the inputs of the neural network of which hidden layer has 20 neurons. Color-to-concentration calibration has been performed before commencing the main experiments. Once this calibration is completed, the temporal changes of the concentration of the DMF has been quantitatively analyzed by using the constructed measurement system.