• The Journal of Korean Academy of Prosthodontics
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• v.34 no.4
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• pp.791-799
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• 1996

The purpose of this study was to compare the shear bond strength of adhesion bridge by various resin cements. One hundred and foully 1st premolars were used. The teeth were cut below 2mm from CEJ and the coronal portions were used. The coronal portions were embeded with the acrylic resin and trimmed with sic paper until the flat plane with ${\phi}$ 4mm above acrylic resin sticks in height 5mm were casted with nonprecious metal and the using surfaces were treated with sic paper from #200 to #1200 and polished with alminum oxide paste. And then, the using surfaces were sandblasted and treated with the electrochemical etching. The teeth were divided into three groups of fourty two each. In group I, teeth and specimens were cemented with Panavia 21 In group II, teeth and specimens were cemented with Superbond In group I, teeth and specimens were cemented with All-Bond & composite resin cement Each group was subdivided into three subgroups according to the storage period ; one-day storage, fifteen-day storage, and thirty-day storage. The special jig was made. Then, the specimen and jig were mounted to Instron Universal Testing Machine and the failure were measured. The results were as follows. 1. There was statisfically significant difference between the failure loads of group I and group II and III after one day storage(P<0.01), 2. There was statisfically significant difference between the failure loads of group II and group I and III and between group I and group III at fifteen day storage(P<0.01). 3. There was statisfically significant difference between the failure loads of group I and II and group III after thirty day storage(P<0.01). 4. There was statisfically significant difference between the failure loads of one day storage and fifteen and thirty days storages in group III (P<0.01).

• Proceedings of the Korean Magnestics Society Conference
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• 2011.12a
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• pp.14-14
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• 2011

Limited understanding of the surface properties of $Pt_3Ni$ for the oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cell (PEMFC) has motivated the study of magnetic properties and electronic structures of Pt segregated $Pt_3Ni$ (111) surface during adsorption of oxygen molecule on it. The first principle method based on density functional theory (DFT) is carried out. Nonmagnetic Pt has induced magnetic moment due to strong hybridization between Ni 3d and Pt 5d. It is found that an oxygen molecule prefers bridge site with Pt rich subsurface environment for adsorption on the surface of Pt segregated $Pt_3Ni$ (111). It is seen that there is very small charge transfer from $O_2$ to Pt. The curve of energy versus magnetic moment of the oxygen explains the magnetic moments in transition states. We found the dissociation barrier of 1.07eV significantly higher than dissociation barrier 0.77eV on Pt (111) suggesting that the dissociation is more difficult on Pt segregated $Pt_3Ni$ (111) surface. The spin polarized densities of states are presented in order to understand electronic structures of Pt and $O_2$ during the adsorption in detail.

• Journal of Environmental Impact Assessment
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• v.13 no.1
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• pp.21-31
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• 2004

Construction of highway would influence wildlife habitat being fragmented and deteriorated. It is inevitable to observe the death of animals that are killed by vehicles. Nonetheless the cause and status of animal roadkill have not been studied, and this study first attempted to analyze the roadkill in major highway in Korea. We collected 860 individuals of dead animals in Joongang Highway during 1996-2003. Among them Korean hare(Lepus sinensis) was totaled in 165 individuals(19.2%) with the highest figure; Korean racoon dog(Nyctereutes procyonoides) was 146(17.0%); Korean squirrel(Sciurus vulgaris) 56(6.5%); Korean roe deer(Capreolus capreolus) 26(3.0%). Domestic animals was totaled in 232 individuals(27.0%); domestic dog(Canis familiairis) 25, and domestic cat(Catus felis) 207. This study also categorized habitat as mountain-mountain, mountain-plain, mountain-river, plain-plain, plain-river, river-river in each side of the road. Habitat of mountain-plain was the heightest with 296(38.9%) individuals followed by mountain-mountain with 263(34.6%). This indicates that wild animals associated with mountain habitat was most influenced by the construction of roads. This study implied that we should mitigate the roadkill by designing artificial construction such as eco-bridge, fences along the sideway, and boxes under the highway, underdrain structure, etc. The monitoring and cause of habitat fragmentation with GIS approach should be followed to reduce the roadkill.

• Korean Journal of Heritage: History & Science
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• v.55 no.3
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• pp.74-100
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• 2022

The purpose of this study was to investigate the characteristics of Chinese seowons and to obtain data based on the characteristics of waterscapes unique to Korean seowons. The conclusion of this study from the results of investigation and analysis of the location, water system, and design characteristics of 10 representative traditional seowons in China including Yuelu Seowon(嶽麓書院) conducted based on literature research and field observation is as follows. The water system of Chinese seowons is dualized into an inner and an outer water system, and in general, two and a maximum of three water bodies are superimposed on the outside. The locations of seowons are classified into five types: Four double-sided round water type sites, three converted face water type sites, one three-sided round water type site, a four-sided round water type, and a waterproofing type(依山傍水型). Therefore, compared to the typical Korean seowon facing water in the front and a mountain in the back(背山面水型), the Chinese seowons showed a highly hydrophilic property. The water shapes of the external water system were meandering(46.0%), mooring(36.0%), and broad and irregular(9.0%). In addition, water conception(水態) were streams(31.8%), rivers(27.3%), springs(13.6%), falls(9.1%), lakes(4.5%) and ponds(4.5%), in that order. As for waterscapes of the water system inside the seowon, there were seven in Akrok Seowon and four in Mansong Seowon, indicating a comparatively higher number of waterscapes. Since the 27 detailed waterscapes in 10 seowons that were the subject of the study were classified into six types including ponds and half-moon ponds, they appeared to be more diverse than the Korean seowon. It is noteworthy that in the interior waterscape of the traditional Chinese seowon, the ritualistic order, where at least one half-moon pond or square pond(方池) was arranged, is well displayed. In particular, the half-moon pond(伴池), which is difficult to find in Korean seowon, was found to be a representative waterscape element, accounting for 42.8%. If the square pond of Nanxi Seowon based on Zhu Xi's poem 「Gwanseoyugam(觀書有感)」 is also treated as a square-shaped half-moon pond, the proportion of half-moon ponds in the waterscape will be as high as 50%. The pond shapes consisted of 28% square, 24% each for free curve and round shape, 20% for semi-moon shape, and 3.8% for mountain stream type. This seems to differ greatly from the square-shaped Korean seowon. On the other hand, there were a total of 10 types of structures related to the waterscape inside the Chinese seowon: 11(26.8%) pavilion and bridge sites, five gate room sites(牌坊: 16.5%), four gate and tower sites(樓, 1.4%), two Jae sites(齋, 6.2%), and one site each(3.1%) of Heon(軒), Sa(祠), Dae(臺), and Gak(閣). In particular, the pavilions inside seowon were classified into three types: landscape pavilion(景觀亭 27.2%), tombstone pavilion(碑亭, 18.2%), and banquet pavilion(宴集亭, 54.5%). In general, it was confirmed that the half-moon pond with a pedestal bridge, and the pavilion were the major components with a high degree of connection that dominate the waterscape inside the Chinese seowon.

• Archives of Craniofacial Surgery
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• v.10 no.2
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• pp.61-66
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• 2009

Purpose: The aim of this study is to establish anatomical dimension of the nose and nostril shape in Korean twenties. Methods: Authors measured anthropometry of nose in Korean youths 1,000 individuals (male 363, female 637) and analyzed stastically them. Results: The mean measurements are as follows. 1. The shape of nostrils was classified into 7 types by the angle between both long axis of nostril (male / female). Type I ($<40^{\circ}$)1.7% / 1.72%, Type II ($41-70^{\circ}$) 26.17% / 29.35%, Type III ($71-100^{\circ}$) 39.94% / 38.77%, Type IV (unclassified) 3.85% / 5.80%, Type V ($101-130^{\circ}$) 20.93% / 17.89%, Type VI ($131-180^{\circ}$) 7.43% / 5.96%, Type VII ($>180^{\circ}$) 0% / 0.47% 2. Lengths (male/female) Width of nasal root: $25.29{\pm}2.25mm/24.72{\pm}2.40mm$ Width of nose: $37.63{\pm}2.46mm/34.77{\pm}2.11mm$ Width of columella: $7.18{\pm}0.92mm/6.92{\pm}0.86mm$ Width of alar: $4.99{\pm}1.00mm/4.74{\pm}0.91mm$ Width of nostril floor: $10.98{\pm}1.40mm/10.13{\pm}1.73mm$ Protrusion of nasal tip: $17.12{\pm}1.95mm/16.88{\pm}1.84mm$ Length of alar: $27.10{\pm}2.21mm/24.66{\pm}2.18mm$ Length of nasal root: $17.37{\pm}2.51mm/16.08{\pm}2.90mm$ Depth of nasal root: $7.83{\pm}1.63mm/6.82{\pm}1.36mm$ Length of columella: $8.13{\pm}1.40mm/7.30{\pm}1.46mm$ Height of nose: $60.50{\pm}8.90mm/59.14{\pm}9.22mm$ Height of nasal bridge: $52.68{\pm}7.49mm/50.57{\pm}7.71mm$ 3. Angles Nasofacial angle: $30.19{\pm}3.43^{\circ}/29.13{\pm}6.31^{\circ}$ Nasofrontal angle: $134.88{\pm}7.25^{\circ}/139.94{\pm}6.33^{\circ}$ Nasolabial angle: $95.08{\pm}8.95^{\circ}/95.80{\pm}8.93^{\circ}$ 4. Nasal index: $72.60{\pm}9.57%/68.21{\pm}7.03%$ Nasal tip protrusion-nasal height index: $45.64{\pm}5.21%/47.09{\pm}5.21%$ Nasal tip protrusion-nasal width index: $32.61{\pm}6.83%/31.63{\pm}6.71%$ Conclusion: These data could be useful reference for anthropometry of nose in Korean twenties.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.869-881
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• 1999

Inchon International Airport Elevated Road Way is located between the Passenger Terminal Building and Transportaion Center which are Inchon International Airport core construction projects. The deck of the bridge is consists of 5-span or 6-span continuous pre-stressed concrete slab. Steel form has been used to enhance the quality of texture on concrete slab. Steel form has been used to enhance the quality of texture on concrete surface, lower surface of deck slab with the two way arch has been manufactured by highly professional manner in order to get an beautiful exterior architectural looks. The prestressed concrete deck slab is mass concrete structures with a high-specified concrete strength and a varying section in the range of 0.95-2.8m thickness. Therefore high risks of thermal cracking occurrence by heat of hydration highly are expected. To resolve such problem, we adopted type 1 cement and pipe cooking method at construction site through mass concrete specimen test and 3-dimensional analysis. For Pipe cooling we used 25mm diameter stainless pipes with wrinkles. Cooling pipe with spacing 50-60cm has been installed. And continuous pipe cooling with cooling water of 15$^{\circ}C$ was conducted for 2days. In present 8 span of all 29 spans construction has been completed. No thermal cracking heat hydration has been observed yet.

• Journal of Chest Surgery
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• v.15 no.2
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• pp.188-193
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• 1982

Between 1967 and 1980, a total of 99 patients with a benign stricture of esophagus, resulting from a chemical burn, underwent a reconstructive procedure in which various segments of colon were used to bridge the gap between the cervical esophagus and the stomach. There were 42 males and 57 females and most were in their twenties and thirties. The most frequent site of the stricture was upper 1/3 of the thoracic esophagus [48.5%] and the next most common site was the low cervical esophagus [23.2%]. In 89 cases, the right colon with or without the terminal ileum was used as the conduit in an isoperistaltic manner and in 10, the left colon was used in an antiperistaltic position, because the right colon was not suitable as the conduit. There was a higher incidence of regurgitation [90% vs 0%], leakage at cervical anastomosis [80% vs 27%] and stenosis at anastomotic site [70% vs 15%] in an antiperistaltic left colon anastomosis, as compared to isoperistaltic right colon anastomosis. This was felt to be due to the orad peristaltic motion of the transplanted colon which acted as a functional obstruction distal to the esophagocolic suture line, resulting in breakdown of the anastomosis, leakage and eventual stenosis at the site of anastomosis. In conclusion, colon is useful and effective conduit as an esophageal substitute. Either the right or the left colon can be used for this purpose, provided that it is placed in an isoperistaltic position to minimize some of the complications listed above.

• Journal of Mechanical Science and Technology
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• v.19 no.4
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• pp.1036-1043
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• 2005

Concentric annular heat pipes (CAHP) were fabricated and tested to investigate their thermal characteristics. The CAHPs were 25.4 mm in outer diameter and 200 mm in length. The inner surface of the heat pipes was covered with screen mesh wicks and they were connected by four bridge wicks to provide liquid return path. Three different heat pipes were fabricated to observe the effect of change in diameter ratios between 2.31 and 4.23 while using the same outer tube dimensions. The major concern of this study was the transient response as well as isothermal characteristics of the heat pipe outer surface, considering the application as uniform heating device. A better performance was achieved as the diameter ratio increased. For the thermal load of 180 W, the maximum temperature difference on the outer surface in the axial direction of CAHP was $2.3^{\circ}C$ while that of the copper block of the same outer dimension was $5.9^{\circ}C.$ The minimum thermal resistance of the CAHP was measured to be $0.004^{\circ}C/W.$ In regard to the transient response during start-up, the heat pipe showed almost no time lag to the heat source, while the copper block of the same outer dimensions exhibited about 25 min time lag.

• International Journal of Highway Engineering
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• v.15 no.2
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• pp.159-167
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• 2013

PURPOSES : In this study, the effects of when median exclusive bus lanes were applied to Daejeon trunk road (Wolpyeng crossway~Seodaejeon crossway, 6.3km) and (Daeduck Bridge 4~Kyeryong 4, 2.6km) by Microscopic Simulation VISSIM (5.0) was studied. The median exclusive bus lanes are one of the measures of transportation system manage techniques that can especially improve the efficiency of public transportation facilities. METHODS : According to the analysis of VISSIM on the Gyerong mainroad and Daedeok mainroad, when the median exclusive bus lanes were applied unlike when the roadside bus-only lanes were applied, the average travel speed of vehicles decreased but the average delay time and travel time increased. This arised from the changes in the geometric structure of the road which occurred the reduction of vehicle lane in the center of the road. RESULTS : In the case of bus, on the other hand, the average travel speed increased but the average delay time and travel time decreased. This is because the problems such as illegal parking and stopping, secondary road in out vehicle, and conflict of intersection right turn that roadside bus-only lanes occurred was solved. CONCLUSIONS : Although the introduction of median exclusive bus lanes will have a negative effect on general traffic flow due to the aggravation of travel, decrease of passenger car usage will lead to decrease of traffic volume. Therefore, smooth vehicle travel is expected.

• Journal of Biomedical Engineering Research
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• v.25 no.1
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• pp.65-70
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• 2004

In this paper, we described 23 cases of animal experiment with our pneumatic ventricular assist device and new durability-improvement method. The blood pump consists of blood housing, and back plate made by the injection molding of isoplast, and the diaphragm fabricated by dipping of polyurethane solution onto the aluminum mold. Its volume was 75 $m\ell$ and in-vitro test showed that maximum output was 4.5 $\ell$/min at the 100 mmHg. The adult female sheep with weight of 50 ＋ 10 kg were employed for tile in-vivo experiments and the mean blood flow was sustained at 3.0 1/min. 4 animals survived more than 15 days and the longest survival time was 28 days. In the prior 10 cases, the major causes of death were the tearing of diaphragm at the diaphragm to blood housing junction. By the new mesh and alumina ball milling methods, the durability was enhanced, and its qualitative and quantitative improvement was proved via the in-vivo and in-vitro methods. Animal experiments demonstrated that all the physiologic parameters a ere maintained within the permissible ranges and no thrombus formation was observed through the visual and blood test. The in-vivo experiments demonstrated our pneumatic ventricular assist device to he one month's bridge to transplantation device.