• Korean Chemical Engineering Research
• /
• v.51 no.6
• /
• pp.774-779
• /
• 2013

We synthesized the solution processible monodispersed $TiO_2$ crystalline nano-sol with ~ 5 nm in size by sol-gel method. Through the spin-coating of crystalline $TiO_2$ nano-sol at low processing temperature, we could make even blocking interlayer on the rough FTO transparent electrode substrate. The rough FTO surface could be gradually smoothed by the spin-coating of nano-crystalline $TiO_2$ sol based blocking interlayer. The 1, 2.5, 5, and 10 wt% of nanocrystalline $TiO_2$ sol formed 29, 38, 62, and 226 nm-thick of blocking interlayer in present experimental condition, respectively. The 5 and 10 wt% of $TiO_2$ nano-sol could effectively fill up the valley part of bare FTO with 48.7 nm of rms (root mean square) roughness and consequently enabled the ZnO to be grown to vertically aligned one dimensional nanorods on the flattened blocking interlayer/FTO substrate.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.35 no.4
• /
• pp.90-104
• /
• 2007

Landmarks like high-rise building are one of the important elements for the enhancement of city identity and provides the hierarchy of city streets, playing a central and symbolic role in cities. Research on physical attribute of landmarks, such as height, distance, location and shape, which are suitable for a city scale, can help a city create a distinct image and maintain comprehensible structure. To achieve this purpose, it is necessary to understand the spatial and cognitive characteristics of a landmark for the establishment and management of it. The results of this study can be summarized as follows: 1. The level of representativeness of a landmark increases in proportion to the degree of cognitive intensity on it. The relation between representativeness and cognitive intensity can be explained as the log-function as follows: Log(the number of people who respond "It has representativeness")=$-1.2579+1.5908{\times}$(cognitive intensity); 2. There are a few differences based on the attributes of respondents: while gender has no distinct influence, residential period and age show statistically meaningful influence on cognitive intensity of a vertical landmark Cognitive intensity of an individual landmarks especially, differs according to the class of main users. Because of frequent changes in occupation or employment, respondents consider the distance from a residential area more important than the distance from a working area in evaluating cognitive intensity of landmarks; 3. landmark can be classified into two kinds: a district landmark and an urban landmark A district landmark is closely connected with physical attributes of the landmark itself, such as distance, size and height. An urban landmark is mainly related to cognitive attributes such as the image and identity of a city as a whole. As a result, the landmark analysis data in this research provides spatial order and identity in a city. It is difficult to establish and reinforce the image of a city as a single element ike a landmark. However, withy steady follow-up research, this study could be seen as a systematic and logical model to improve urban landscape and image.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.3
• /
• pp.230-236
• /
• 2020

A trash screen is installed in front of the inflow channel of a drainage pumping station, sewage treatment plant, and a power plant to block floating contaminants. The bottleneck phenomenon, which decreases the water inflow, causes damage to the damper as a result of clogging in between the screen if string type obstacles are not removed. In this paper, the apron was removed, and the screen was expanded, to prevent breakage of the bottleneck phenomenon and string type obstacles. This was designed using an extended rake by adding an inner rake in between the screen interspace to remove the bottleneck phenomenon and string type obstacles. To design the inner rake that satisfies the allowable stresses of the existing damper rake, the experiment points were determined according to the experimental design method using the inner rake vertical length and the thickness of the reinforced section as parameters. The use of the ANSYS static structural module and statistical analysis tool R software gives the optimized shape according to the response surface method. The relative error between the response surface analysis results and the simulation results was 1.63% of the determined optimal design-point rake length of 210.2 mm and the reinforcement section thickness of 2 mm. Through empirical experiments, a test rake was constructed to the actual size, and approximately 97% of the bottleneck phenomenon and string type obstacles could be removed.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.23 no.5
• /
• pp.345-357
• /
• 2011

Recently, as part of diversifying energy sources and earth environmental issues, technology development of new renewable energy using wave energy is actively promoted and commercialized around Europe and Japan etc. In particular, OWC(Oscillating Water Column) wave power generation system using air flow induced by vertical movement of the water surface by waves in an air-chamber within caisson is known as the most efficient wave energy absorption device and therefore, is one of the wave power generation apparatus the closest to commercialization. This study examines air flow velocity, which operates turbine(Wells turbine) directly in oscillating water column type wave power generation structure from two-and three-dimensional numerical experiments and discusses optimal shape of oscillating water column type wave power generation structure by estimating the maximum flow rate of air according to change in shape. The three-dimensional numerical wave flume was applied in interpretation for this study which is the model for the immiscible two-phase flow based on the Navier-Stokes Equation. From this, it turned out that size of optimal shape appears differently according to the incident wave period and air flow is maximized at the period where minimum reflection ratio occurs.

• Archives of design research
• /
• v.14
• /
• pp.1-7
• /
• 1996

Designers often hesitate to decide the shape, size, and layout of a product. Though ergonomic principles and data are absolutely needed in this process, they don have enough guidelines to refer. For the refrigerator designers, they also are not convinced of their decision: the vertical position of the freezing and refrigerating rooms, the height of shelves, the shape of door-handle, etc. To support the refrigerator design, we applied several ergonomic methods to the evaluation of refrigerator. EMG was measured to evaluate the load of users lumbar muscle. Based upon the experimental EMG data, we developed a model to estimate the relative load corresponding to the height of refrigerator shelves. Two different layouts of a refrigerator, R/F and F/R styles, were compared with the model. A three-dimensional motion analysis method was used to evaluate the users motion of using a refrigerator. Ten door-handles with the different shapes and positions were evaluated by tracking the rotations of the users arm. Video protocol analysis was used to evaluate the user interface of a control panel in a refrigerator. Finally, we suggested several ergonomic design guidelines based on the facts found in this research and the anthropometric data of the Korean adults. The results of this study can be applied to the ergonomic design of refrigerators

• Archives of Plastic Surgery
• /
• v.36 no.4
• /
• pp.512-515
• /
• 2009

Purpose: Neurofibromatosis(NF) is an autosomal - dominant systemic disease. Up to fifty percent of patients with NF are reported to have concomitant vascular abnormalities. In the resection of a larger NF, the risk of uncontrolled hemorrhage is much higher due to the difficulty of hemostasis of large vessels within the tumor. We ligated the base of the giant NF with a simple loop - shaped ligation before removal of the giant NF in both buttocks. And then we could successfully reduce the amount of hemorrhage during the operation. Methods: A 46 - year - old female patient presented for giant masses of both gluteal area, which has been growing slowly for the last ten years. Each mass was about $30{\times}20cm$ in size. After designing the elliptical resection margin, we tightened the tumor base by using continuous loop - shaped suture ligation(weaving the thread up and down in a loop - shaped pattern, leaving a space of 2 cm between each loop) with a straight needle and prolene 2 - 0. After skin incision, we proceeded the dissection toward the central and inferior side of the mass obliquely while we avoided breaking large vascular sinuses. We resected the tumor in a wedged - shape. Subcutaneous tissue was sutured layer by layer and skin was closed by vertical mattress and interrupted suture. The loop - shaped ligation of the base was removed and compressive dressing was done with gauzes and elastic bandages. Results: Postoperative complications such as infection, hemorrhage, hematoma, and dehiscense did not occur. Perioperatively the patient was sufficiently transfused with five units of blood and two units of fresh frozen plasma. During the subsequent 1 year follow - up, the functional and cosmetic result was excellent. Conclusion: A continuous loop - shaped suture ligation procedure along the base of the giant NF effectively reduced the amount of hemorrhage during the operation, made dissection and ligation of vessels easily and quickly, and shorten the operating time and postoperative recovery time.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2009.06a
• /
• pp.187-187
• /
• 2009

Opening of fractures induced by shear dilation or normal deformation can be a significant source of fracture permeability change in fractured rock, which is important for the performance assessment of geological repositories for spent nuclear fuel. As the repository generates heat and later cools the fluid-carrying ability of the rocks becomes a dynamic variable during the lifespan of the repository. Heating causes expansion of the rock close to the repository and, at the same time, contraction close to the surface. During the cooling phase of the repository, the opposite takes place. Heating and cooling together with the, virgin stress can induce shear dilation of fractures and deformation zones and change the flow field around the repository. The objectives of this work are to examine the contribution of thermal stress to the shear slip of fracture in mid- and far-field around a KBS-3 type of repository and to investigate the effect of evolution of stress on the rock mass permeability. In the first part of this study, zones of fracture shear slip were examined by conducting a three-dimensional, thermo-mechanical analysis of a spent fuel repository model in the size of 2 km $\times$ 2 km $\times$ 800 m. Stress evolutions of importance for fracture shear slip are: (1) comparatively high horizontal compressive thermal stress at the repository level, (2) generation of vertical tensile thermal stress right above the repository, (3) horizontal tensile stress near the surface, which can induce tensile failure, and generation of shear stresses at the comers of the repository. In the second part of the study, fracture data from Forsmark, Sweden is used to establish fracture network models (DFN). Stress paths obtained from the thermo-mechanical analysis were used as boundary conditions in DFN-DEM (Discrete Element Method) analysis of six DFN models at the repository level. Increases of permeability up to a factor of four were observed during thermal loading history and shear dilation of fractures was not recovered after cooling of the repository. An understanding of the stress path and potential areas of slip induced shear dilation and related permeability changes during the lifetime of a repository for spent nuclear fuel is of utmost importance for analysing long-term safety. The result of this study will assist in identifying critical areas around a repository where fracture shear slip is likely to develop. The presentation also includes a brief introduction to the ongoing site investigation on two candidate sites for geological repository in Sweden.

• Journal of Korean Society of Steel Construction
• /
• v.26 no.4
• /
• pp.263-275
• /
• 2014

In this study, connection of steel reinforced concrete(SRC) column and composite beam which consists of H-section and U-section members were tested under cyclic loading. An essential point of the composite beam is the structural performance of welded joint between the H-section and the U-section members. To improve the structural performance of joint of two beam members, vertical stiffeners, trapezoidal stiffeners, and top bars were used. Five full-scaled specimens were designed to study the effect of a number of parameters on cyclic performance of connections such as H-section beam size($H-500{\times}200{\times}10{\times}16$, $H-600{\times}200{\times}11{\times}17$), the presence of stiffeners and top bars, and the presence of no weld access hole(WAH) method. Based on the test results, deformation capacity of the specimens with H-500 series beam and H-600 series beam were 4% and 3% rotation angle, which is the requirement for the Special Moment Frame and Intermediate Moment Frame(IMF), respectively. Test result showed that deformation capacity of connection with stiffeners and top bars is greater than that of connection without stiffeners and top bars. Finally, energy dissipation capacity and strain profile of specimens were summarized.

• Korean Journal of Soil Science and Fertilizer
• /
• v.30 no.3
• /
• pp.226-233
• /
• 1997

To investigate the salt accumulation in the plastic film house soils, bulk density, electrical conductivity(EC), exchangeable canons and water soluble anions were determined at different depths(0~60cm) in the salt-accumulated plastic film house soils in Yesan, Chungnam, Korea. Bulk density were increased from $1.2Mg/m^3$ to $1.5Mg/m^3$ as the depth changed from 0cm(top soil) to 30cm(subsoil) below the soil surface, whereas the bulk densities between 30cm to 60cm slightly decreased to $1.42Mg/m^3$. These changes of soil bulk densities might influence the porosity and pore size distribution, resulting in affecting the water flow throughout, soil layers. Electrical conductivity and Exchangeable sodium percentage(ESP) for 0 to 10cm soil layer were 5.08 dS/m and 6.4, respectively, while the EC was decreased to less than 1.63 dS/m in 20~30cm depth and about 0.7 dS/m. Salt accumulation patterns in the plastic film house soils might be influenced by the changes of the bulk densities in soil.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.8 no.1
• /
• pp.1-13
• /
• 2003

To investigate the community structure and meiofaunal density in seagrass/bare non-seagrass beds, a survey was conducted at three seagrass bed locations in Doomoojin of Baegryongdo, inner harbor of Eocheongdo in May 1999, and Yulim of Dolsando for every month from February to July 1999. Meiobenthic samples were collected from sediments within seagrass beds (SB) and non-seagrass bed (or adjacent to barren sand area, NSB). Nematodes were the most dominant group among representative 13 meiofaunal groups. The sub-dominant groups were benthic for-aminiferans, benthic harpacticoids, and annelids. The highest density of meiofauna was recorded at a seagrass bed of Yulim (7,244 ind/10 $\textrm{cm}^2$ in June), and lowest density was recorded at a non-seauass bed of Baegryoungdo (438 ind/ 10 $\textrm{cm}^2$ in May). For vertical distribution, the highest density of meiofauna was recorded at 0-2 cm depth, and the density abruptly decreased with depth in all stations. The density of meiofauna in size between 0.125 m and 0.25 mm was maximum. Sediment types for the study areas ranged from sandy to sandy mud by the Folk's classification. The density of total meiofauna, the number of taxa, and the density of the dominant groups (nematodes, benthic for-aminiferans, benthic harpacticoids, annelids) between SB and NSB were significantly different. The results clearly showed the importance of seagrass bed as suitable habitat for meiofauna.