• Korean Journal of Hydrosciences
• /
• 제6권
• /
• pp.67-79
• /
• 1995

The reattachment of buoyant efflluent to a shore in a crossflow is investigated experimentally. The effluent is prodeced by discharging heated water through a projected side channel into a confined crossflow of the same depth. In the projecting effluent, the size of recirculating region, which is formed by deflected thermal plume on the lee of the effluent, tends to increase, but the maximum temperature decreases in the direction of the crossflow and it has more uniform transverse spreading compared to non-projected type. The heat flux across the crossflow is found to be independent of the projceted length of the side channel under relatively high buoyancy flux on the contrary to low buoyancy flux. The reattachment of th effluent can be specified by both velocity ratio and densimetric Froude number, whereas only the velocity ratio is governing factor to the reattachment of the effluent in the case of non-projecting type.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2015년도 추계 학술논문 발표대회
• /
• pp.28-29
• /
• 2015

Due to the big fire in Uijeongbu, the status of construction, fireproof materials and structural method were examined to prevent fire propagation through outside insulation parts of urban living homes. Through research and experiments, the following results were obtained. It was confirmed that outside heat-insulation wall method was used in a large number of urban living homes which were made of materials and structures spreading fire easily.Through experiments, it was revealed that lightweight plate material, as a fireproof material, can save the cost as well as the period of construction and obtain more than 30 minutes of evacuation time which is twice the maximum evacuation time.

• 국제초고층학회논문집
• /
• 제6권3호
• /
• pp.271-277
• /
• 2017

Safety, livability, and efficiency are the three prominent problems of tall buildings, which are also the severe challenges to designers. We proposed the idea of building the sky town to solve these problems, which can be summarized in two sentences, one is tall building multi-storised, and another one is vertical facilities municipal-infrastructurised. The tall building can be horizontally cut into several multi-storey buildings by some large platforms. The platform extends a certain width to block the fire from spreading. Tall buildings are connected together as a group. One of them is a traffic core, which is used for vertical transportation and MEP. It connects to traffic center such as metro, while most of the other tall buildings' cores can be very much released, so as to achieve maximum efficiency of floor usable area and to give good traffic organization. By combining traffic core, platforms, and multi-storey buildings' inner traffic, a transportation network is formed. Finally, we refer to the design of Raffles City Chongqing to make a sketch of sky town.

• 한국해양공학회지
• /
• 제15권3호
• /
• pp.20-27
• /
• 2001

After using the filtering method, wave parameters are calculated by the spectral analysis and wave by wave analysis. Extreme environments and higher wave characteristics int he Chujeon Sea are analyzed using the observed wave data. Higher wave has been intensely emphasized as an important environmental force parameter in several recent research works. The aims of this study are to summarize the distribution of extreme environment for wind waves, and to find occurrence probability of higher wave in Chujeon Sea. Ocean wave statistics varying with sea state are found to respond linearly to the spectral peakedness parameter Qp, mean run-length and Ursell number. Although the spreading of the field results is large, it may be concluded that the tendency of wave group formation depends on the spectral peakedness parameter Qp. Extreme wave is estimated to apply various model distribution functions by using the monthly maximum significant wave parameters which can be used to the design and analysis of coastal structures.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
• /
• pp.221-224
• /
• 2001

A new code: LS code was proposed for IMT-2000 CDMA system. The code has special properties during a certain time of interval: 1) perfect autocorrelation 2) perfect crosscorrelation. The perfect autocorrelation means that the autocorrelation has nMaximum for zero time-offset and zero for other times during a certain time. Moreover the perfect crosscorrelation means that the crosscorrelation has zero during a time of interest. In the LAS-DMA system, the LS code is only used in the spreading of data bits in contrast to the conventional CDMA system. Therefore the LS code pair setting and allocation order should be dealt with carefully considering the special properties of LS code. This paper is intended as an investigation of the setting LS code pair and the sequential allocation method. Firstly, the optimum LS code pair set is proposed in order to minimize PAPR. Secondly, the sequential allocation method is studied to either minimize PAPR or expand IFW.

• 한국분무공학회지
• /
• 제21권1호
• /
• pp.58-63
• /
• 2016

This study presents the dynamic characteristics of an impinging droplet on hydrophobic and hydrophilic surfaces with various texture area fractions. The flat surface was fabricated by using the drilling technique to make micro-meter hole-patterned surfaces, which shows hydrophobic textured surfaces. Moreover, the hydrophilic textured surfaces were manufactured by anodizing technique on the micro-meter hole-patterned surfaces to generate multi-layer surfaces. Impinging droplet experiments were conducted for various hole-patterned surfaces, with changing impact velocity and texture area fractions. It is observed that an anodizing technique increases wettability by decrease in hole diameter on the textured surfaces. However, micro-drilled surfaces decreases wettability because the hole diameter was so large that air can be trapped under the holes. In addition, the maximum spreading diameter decreases with the texture area fraction for the micro-drilled surfaces because of decrease in wettability.

• 대한조선학회논문집
• /
• 제41권1호
• /
• pp.1-7
• /
• 2004

GUI program for analyzing directional spectrum waves is introduced in this paper Basically, MLM (Maximum Likelihood Method) was used for this program which was additionally consisted of performing spectral and time domain analysis for two dimensional irregular waves. Moreover, the directionality of directional spectrum waves generated by single summation and double summation method was investigated based on MLM. The directionality from each summation method has good agreement compared with that of target wave spreading function in the case of single wide directional spectrum waves. In addition to this, the resolution of directionality in double summation method was investigated as introducing coherence function between each wave component

• 한국재료학회지
• /
• 제9권12호
• /
• pp.1229-1233
• /
• 1999

본 연구에서는 (N-docosyl quinolinium)-TCNQ (1:2) 착물의 LB초박막을 제작하였다. LB막의 누적을 위한 최적조건을 구하기 위하여 subphase 온도, barrier 압축속도 및 분산량을 변화시키면서 표면압-면적(${\pi}$-A) 등온선 특성을 측정하였다. 그리고 전이비, UV-vis의 최대 흡광도, 정전용량 및 두께를 측정하여 LB막의 누적상태를 확인하였다. 그 결과 분자수준으로 잘 제어된 양호한 LB막이 제작되었음을 알 수 있었다..

• Journal of Periodontal and Implant Science
• /
• 제26권1호
• /
• pp.188-201
• /
• 1996

One of the initial events required for periodontal regeneration is the attachment, spreading and proliferation of fibroblasts at the healing sites. These have been reported that minocycline stimulates the attachment of gingival fibroblasts and periodontal ligament cells and $TGF-{\beta}1$ enhances the proliferation of periodontal ligament cells. The purpose of this study was to evaluate and confirm the effect of minocycline and $TGF-{\beta}1$ on human gingival fibroblasts and periodontal ligament cells. That gingival fibroblasts and periodontal ligament cells used in this study were obtained from the explants of healthy periodontal ligaments and gingival tissues of extracted 3rd molars or premolar teeth extracted from the patients with orthodontic treatment. The cells were cultured in ${\alpha}-MEM$(minimal essential medium) supplemented with antibiotics and FBS(fetal bovine serum) at $37^{\circ}C$ in a humidified atmosphere of 5% carbon dioxide-95% air. Cells were used between the 5th to 8th passage in this study. The attachment and activity of both cells were evaluated by MTT assay. The results were as follows: 1. Maximum gingival fibroblast attachment was seen at a $50{\mu}g/ml$ dose of minocycline, while maximum periodontal ligament cell attachment was seen at a $100{\mu}g/ml$, and exposure of both cells to minocycline above maximal attachment dose results in a decline from maximum attachment. 2. The activity values of both cells tested minocycline were below to the control activity values at all concentrations. 3. The attachment values of both cells tested $TGF-{\beta}1$ were below or similar to control attachment values. On the above the findings, minocycline stimulated the cell attachment of gingival fibroblasts and periodontal ligament cells and $TGF-{\beta}1$ enhances the cell activity of periodontal ligament cells.

• 한국농공학회지
• /
• 제23권3호
• /
• pp.65-77
• /
• 1981

The Compaction of fill dam is very important for increasing of the safty of dam. Vibration roller is used for the compaction of pervious materials such as sand and gravel. The principal objects of this study are to give a comstruction criteria of vibration roller and to find out the relationship between dry density and permeabity of pervious soil after compaction. The results in this study are summerized as follows. 1.The relationship between maximum dry density (Υdmax) and optimum moisture content(Wo) of modified compaction test is Υdmax=2. 74-0. 064w0 2.The maximum dry density decrease with increasing fine particle(n) and the relative formular is n==ae-brdmax 3.The maximum dry density is influenced more by passing rate of number 200 sieve than 4 sieve. 4.The coefficient of permeability are similar when the degrees of compaction are equal even though the spreading thickness of soil are different. 5.The coefficient of permeability(K)is greatly influence by fine particle passing number 200 sieve, and those relationship is inversely proportionate. 6.The K values of pervious soil are from 10-0 cm/sec to 10-4 cm/sec when degree of compaction by a modified method is from 90 to 95percent. 7.The coarser material is little influenced on the permeability with different density. 8.The increasing rate of permeability with decreasing degree of compaction is more influened by fine pacticle than number 200 sieve. When degree of compaction decrease from 100 percent to 90 percent the K values of SM and GM increase about 20 times but GW increase 6 times only. 9.The effect of compaction by vibration roller is greatly influenced by 6 passes and the increasing rate of the effect is decraased at 8 passes. 10. In order to get the degree of compaction of 95 percent or more, 6 to 8 passes of roller are generall required with 30 cm thickeness of soil for 4.5 ton to 6.5 ton vibration roller and 7 to 8 passes is required with 50cm thickness for 8 to 12 ton roller.