• Bulletin of the Korean Chemical Society
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• v.30 no.8
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• pp.1793-1797
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• 2009

Soft lithography of polydimethyl-siloxane (PDMS), an elastomeric polymer, has enabled rapid and inexpensive fabrications of microfluidic devices for various biochemical and bioanalytical applications. However, fabrications of nanostructured PDMS components such as nanoslits remain extremely challenging because of deformation of PDMS material. One of the well-known issues is the unwanted contact between the surfaces of PDMS roof and bottom substrate, called ‘roof collapse’. Here we have developed a novel approach for the facile stabilization of PDMS nanoslits in the low height (130 nm)/width (100 $\mu$m) ratio without roof-collapse. Within 130 nm high nanoslits, we demonstrate the confinement of single DNA molecules. We believe that this approach will serve as a key to utilize PDMS as nanoslits for integrated microfluidic devices.

• Annual Conference on Human and Language Technology
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• 1993.10a
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• pp.193-205
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• 1993

한글의 글자꼴과 장평율 그리고 글줄 길이와 글줄꼴 처리 방식이 가독성에 미치는 효과를 측정하였다. 글자꼴은 명조체, 고딕체, 샘물체를 사용하였고, 장평율은 글자의 가로 대 세로 비율을 1 대 1, 1 대 2 그리고 2 대 1로 변형시킨 세 가지를 사용하였다. 글줄 길이는 60mm와 120mm의 두 가지로 하였고 글줄 끝에서 음절 단위로 끊어 쓴 문장과 어절 단위로 끊어 쓰되 띄어쓰기 여백을 조절한 문장과 조절하지 않은 문장을 사용하였다. 연구결과, 글자꼴에서는 명조체와 고딕체의 가독성이 샘물체보다 좋았고, 가로 대 세로의 비율이 1 대 1이거나 1 대 2인 글자의 가독성이 2 대 1인 글자의 가독성보다 우수하였다. 이러한 연구 결과는 한글 정보 처리 과정에서 자모보다 글자가 중요한 시각 정보로 사용되고 한번 응시하는 동안에 표집되는 글자수가 가독성에 영향을 미칠 수 있다는 사실을 시사한다. 글줄 길이는 120mm일 때의 가독성이 더 좋았고 글줄 끝처리 방식은 가독성에 영향을 미치지 않는 것으로 나타났다.

• Journal of the Korean GEO-environmental Society
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• v.4 no.3
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• pp.51-59
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• 2003

Loading tests were carried out for model geocell to study the reinforcing effect by variation of tensile strength, cell height, soil density and embedded depth of geocell. From the result, it could be seen that the ultimate bearing capacity of the geocell system was influenced rather by the connection strength than by the tensile strength of geocell material. Bearing capacity increased with the increase of height to width ratio of geocell for the same relative density, strength and embedded depth. And the bearing capacity ratio(BCR) was higher at low relative density of sand than that of high relative density. The increase of bearing capacity was higher at geocell with high tensile strength than that of low tensile strength. And the influence was clear at higher relative density. Also the BCR was higher at shallow embedded depth of geocell. Without consideration of tensile strength of material, the application of bearing capacity formula suggested by Koerner seems not suitable for the special case with low tensile strength of geocell material.

• Journal of the Korean Society for Environmental Technology
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• v.19 no.6
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• pp.528-535
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• 2018

In this study, the effect of obstacle aspect ratio on vortex in building canyon was numerically investigated using a computational fluid dynamics(CFD) model. The sensitivity experiments were performed in the cases of increasing building length(L) and height(H) by the width(W) of building canyon. The wind vector fields and secondary reverse vortex in building canyon were discussed in this study. For the horizontal vortex, the vortex zone increased as the building length increases, but the vectors at the middle of building canyon began to change in the case of L/W=2.5. In the case of L/W=3.0, the smaller primary vortex was presented with the secondary reverse vortex. For the vertical vortex, the vortex zone increased as the building height increases, but the direction of vectors at the bottom of building canyon began to change in the case of H/W=2.5. In the case of H/W=3.5, the smaller primary vortex was presented with the secondary reverse vortex.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.639-647
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• 2019

Recently, as the semiconductor integration technology due to miniaturization and high density of electronic equipment have developed, it is importantly recognized the application of thermal control system in order to release inner heat generated from chips, modules, In this study, we considered the heat transfer and pressure drop characteristics in a horizontal channel with four blocks using k-${\omega}$ SST turbulence model During CFD (Computational Fluid Dynamics) analysis, the parameters applied block width, block height, heat source and turbulence generator placement etc. As the boundary conditions of analysis, the channel inlet temperature and flow velocity were respectively 300 K and 3.84 m/s, the heat flux was $358W/m^2$. As a result, the heat transfer performance was decreased as the block width ratio (w/h) was increased, while it was increased as the block height ratio (h/w) was increased. In addition, as the arrangement of heat source size was increased to high heat flux from low heat flux, it was influenced by heat source size and the heat transfer coefficient showed a tendency to increase, When the turbulence generator was installed in the upper part of block No. 1 position the closely to the channel entrance, the heat transfer characteristics was greatly influenced on the whole of four heating blocks. and in oder to consider the pressure drop characteristics, we are able to select the most appropriate turbulence generator's position.

• Wind and Structures
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• v.12 no.4
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• pp.299-312
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• 2009

It has long been studied about the flow around bluff bodies, but the effect of aspect ratio on the sharp-edged bodies in thick turbulent boundary layers is still argued. The author investigates the flow characteristics around a series of rectangular bodies ($40^d{\times}80^w{\times}80^h$, $80^d{\times}80^w{\times}80^h$ and $160^d{\times}80^w{\times}80^h$ in mm) placed in a deep turbulent boundary layer. The study is aiming to identify the extant Reynolds number independence of the rectangular bodies and furthermore understand the surface pressure distribution around the bodies such as the suction pressure in the leading edge, when the shape of bodies is changed, responsible for producing extreme suction pressures around the bluff bodies. The experiments are carried out at three different Reynolds numbers, based on the velocity U at the body height h, of 24,000, 46,000 and 67,000, and large enough that the mean boundary layer flow is effectively Reynolds number independent. The experiment includes wind tunnel work with the velocity and surface pressure measurements. The results show that the generation of the deep turbulent boundary layer in the wind tunnel and the surface pressure around the bodies were all independent of Reynolds number and the longitudinal length, but highly dependent of the transverse width.

• Journal of Convergence for Information Technology
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• v.7 no.2
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• pp.77-82
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• 2017

In this paper, a new security algorithm to recognize the type of the vehicle with the vehicle image as a input image is suggested. The vehicle recognition security algorithm is composed of five core parts, such as the input image, background removal, edge areas extraction, pre-processing(binarization), and the vehicle recognition. Therefore, the final recognition rate of the security algorithm for vehicle type recognition can be affected by the function and efficiency of each step. After inputting image into a gray scale image and removing backgrounds, the binarization is performed by extracting only the edge region. After the pre-treatment process for making outlines clear, the type of vehicles is categorized into large vehicles, passenger cars and motorcycles through the ratio of height and width of the vehicle.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.760-767
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• 2014

An experimental study is carried out to investigate the effect of jet stream in the gab of rectangular cylinders with different length in a parallel arrangement by using PIV method in a circulating water channel. The height(h) of the rectangular cylinder and the gap between the cylinder is 10mm, and the width(B) which is 300mm. The length of the model for flow direction was applied to 30mm, 60mm, 90mm & 120mm, The aspect ratio of a model on the basis of height(H=30mm) is 1, 2, 3 and 4. Reynolds number $Re=1.4{\times}10^4$, $Re=2.0{\times}10^4$, $Re=2.9{\times}10^4$ based on the height(H) of model for the distance of tidal distributions as of water depth have been applied during the whole experiments. The measurement area was set to 5H rear of the cylinder. As a result, Vortex size in the wake area were increased as velocity increased. and high aspect ratio increased through-flow velocity component in the near wake. Velocity deficit increased highly after near-wake area and low aspect ratio.

• The korean journal of orthodontics
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• v.49 no.4
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• pp.222-234
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• 2019

Objective: To investigate the three-dimensional lip vermilion changes after extraction and non-extraction orthodontic treatment in female adult patients and explore the correlation between lip vermilion changes and incisor changes. Methods: Forty-seven young female adult patients were enrolled in this study (skeletal Class III patients were excluded), including 34 lip-protruding patients treated by extraction of four first premolars (18 patients requiring mini-implants for maximum anchorage control and 16 patients without mini-implants) and 13 patients requiring non-extraction treatment. Nine angles, seven distances, and the surface area of the lip vermilion were measured by using pre- and post-treatment three-dimensional facial scans. Linear and angular measurements of incisors were performed on lateral cephalograms. Results: There were no significant changes in the vermilion measurements in the non-extraction group. The vermilion angle, vermilion height, central bow angle, height/width ratio, and vermilion surface area decreased significantly after the orthodontic treatment in the extraction groups, but the upper/lower vermilion proportion remained unchanged. Significant correlations were found between the changes in incisor position and those in vermilion angles, vermilion height, and surface area. Conclusions: Extraction of the four first premolars probably produced an aesthetic improvement in lip vermilion morphology. However, the upper/lower vermilion proportion remained unchanged. The variations in the vermilion were closely related to incisor changes, especially the upper incisor inclination changes.

• Plant Breeding and Biotechnology
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• v.7 no.3
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• pp.186-199
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• 2019

We selected 68 Chinese maize inbred lines to understand the genetic diversity, population structure, and marker-trait associations for eight agronomic traits and 50 simple sequence repeats (SSRs) markers. In this study, effective traits, such as days of anthesis (DA), days of silking (DS), ear height (EH), plant to ear height ratio (ER), plant height (PH), and leaf width (LW) were divided into PC1 and PC2 by PCA analysis for maize inbred lines. Genetic diversity analysis revealed a total of 506 alleles at 50 SSR loci. The mean number of alleles per locus was 10.12. The averages of genetic diversity (GD) and polymorphic information content (PIC) values were 0.771 and 0.743, respectively. Based on a membership probability threshold of 0.80, the population structure revealed that the total inbred lines were divided into three major groups with one admixed group. A marker-trait association using Q + K MLM showed that nine SSR markers (bnlg1017, umc2041, umc2400, bnlg105, umc1229, umc1250, umc1066, umc2092, and umc1426) were related with seven agronomic traits. Among these SSR markers, eight SSR markers were associated with only one agronomic trait (DA, DS, ER, LL, LW, PH, and ST), whereas one SSR marker (umc1229) was associated with two agronomic traits (DA and ST). These results will help in optimizing the choice of inbred lines for cross combinations, as well as in selecting markers for further maize breeding programs.