• Journal of the Korean Society of Industry Convergence
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• v.25 no.4_2
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• pp.587-594
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• 2022

In the 2000s, a lot of cable-type grand bridges are being built in consideration of economic aspects such as the reduction of logistics costs and the distribution of traffic volume due to rapid economic development. In addition, because the recently installed grand bridges are designed in an aesthetic form that matches the surrounding environment as well as the original function of the road bridge, and serves as a milestone in an area and is used as an excellent tourism resource, attracting many vehicles and people, there is an urgent need for a safety structure that can ensure the safety of not only vehicles but also people. In order to make cable-stayed bridge safe on wind for additional five safety structures, main girder models with and without safety structures for wind-tunnel experiments was made, and wind tunnel experiments was carried out to measure aerodynamic force coefficients. Also, wind-resistant analyses of 3D cable-stayed bridge were performed on the basis of wind-tunnel experiment results. From the wind tunnel experiments for the aerodynamic force coefficients of main girder with five safety structures and the wind resistant analyses of cable-stayed bridge without safety structure and with safety structure, it was concluded that the best form of wind-resistant safety was shown in the order of mesh, standard, bracing, hollow, and closed type. And wind-resistant safety of cable-stayed bridge with hollow and closed type on design wind speed 68.0m/sec was not secured. Finally, as five safety structures are installed, maximum rate of stress increments was shown in the order of steel main beam, steel floor beam, concrete floor beam and cables.

• Applied Chemistry for Engineering
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• v.28 no.5
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• pp.576-580
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• 2017

In the present paper, the thermal deactivation characteristics of plate-type commercial $V_2O_5-WO_3/TiO_2$ SCR catalyst were investigated. For this purpose, the plate-type catalyst was calcined at different temperatures ranging from $500^{\circ}C$ to $800^{\circ}C$ for 3 hours. Structural and morphological changes were characterized byXRD, specific surface area, porosity, SEM-EDS and also NOx conversion with ammonia according to the calcine temperature. The NOx conversion decreased with increasing calcine temperature, especially when the catalysts were calcined at temperatures above $700^{\circ}C$. This is because the crystal phase of $TiO_2$ changed from anatase to rutile, and the $TiO_2$ grain growth and $CaWO_4$ crystal phase were formed, which reduced the specific surface area and pore volume. In addition, $V_2O_5$, which is a catalytically active material, was sublimated or vaporized over $700^{\circ}C$, and a metal mesh used as a support of the catalyst occurred intergranular corrosion and oxidation due to the formation of Cr carbide.

• Journal of Periodontal and Implant Science
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• v.35 no.4
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• pp.949-959
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• 2005

이 연구는 임플란트를 식립하기를 원하는 전신건강상태가 양호하며 구강위생상태가 좋은 14명 환자(남자:8명, 여자:6명, 평균나이 : 44세)의 20개의 발치와 내에 흡수성 차폐막(BioMesh. Sam Yang Corporation, Korea)과 함께 탈회냉동 건조동종 골(dem-ineralized freezedried bone allografts, $250-500{\mu}m$. Pacific Coast Tissue Bank, U.S.A.)과 이종골(Bovine-Bone, Bio-Oss 0.25-1.0 mm, Geistlich, Biomaterials and Osteohealth, Switzerland)을 1:1(부피)로 혼합하여 이식한 후 그 치유양상을 관찰하고자 조직학적 및 면역조직화학적으로 평가하였다. 이직재가 탈락되는 것을 방지하기 위하여 발치한 후 1개윌이 경과된 후에 이식재와 차폐막을 위치시켰다. 표본제작을 위하여 이식술을 시행한 지 약 6개윌 후에 임플란트를 식립하기 직전 식립부위에서 trephine bur로 골을 채취하였는데, 20증례 중 7증례에서 임플란트를 식립하기 전에 차폐막이 노출되었다. 차폐막이 노출되지 않은 것을 대조군으로, 노출된 것을 실험군으로 설정하였다. 조직학적인 관찰을 위하여 통상적인 방법에 따라 탈회 표본을 제작하였고, alkaline phosphotase(ALP)틀 이용하여 면역조직화학적 염색을 시행한 후 골 형성 상태를 평가하여 다음과 같은 결과를 얻었다. 본 연구에서는 발치와내에서 골유도재생술 후 나타나는 치유 형태를 5가지 형태로 분류할 수 있었다. Type I, II와 III는 새로운 골 형성을 나타내지 않았고, 면역조직화학적 검사 시 ALP 음성 소견을 나타내었다. Type V는 새로운 골 형성과 ALP 양성 소견을 나타내었으나 염증, 괴사, 결합조직의 증식 등은 없었다. Type IV와 Type V의 차이는 결합조직의 증식여부로 구분되었다. 막이 노출되지않은 증례들 중 7 증례에서는 Type V의 치유 형태를, 2증례에서는 Type IV의 치유 형태를 나타내었다. 막이 노출되었던 증례에서는 Type I, II, III의 다양한 치유 형태를 나타내었다. 본 연구결과, 발치와 내에 골유도재생술을 시행한 후 차폐막의 노출 여부가 신생골 형성에 중요한 영향을 미칠 것으로 사료되며, 본 연구에서 분류한 치유 형태가 향후 골유도재생술 후의 결과 분석에 활용될 수 있을 것으로 사료된다.

• Gut and Liver
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• v.12 no.6
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• pp.722-727
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• 2018

Background/Aims: Although endoscopic bilateral stent-instent placement is challenging, many recent studies have reported promising outcomes regarding technical success and endoscopic re-intervention. This study aimed to evaluate the technical accessibility of stent-in-stent placement using large cell-type stents in patients with inoperable malignant hilar biliary obstruction. Methods: Forty-three patients with inoperable malignant hilar biliary obstruction from four academic centers were prospectively enrolled from March 2013 to June 2015. Results: Bilateral stent-in-stent placement using two large cell-type stents was successfully performed in 88.4% of the patients (38/43). In four of the five cases with technical failure, the delivery sheath of the second stent became caught in the hook-cross-type vertex of the large cell of the first stent, and subsequent attempts to pass a guidewire and stent assembly through the mesh failed. Functional success was achieved in all cases of technical success. Stent occlusion occurred in 63.2% of the patients (24/38), with a median patient survival of 300 days. The median stent patency was 198 days. The stent patency rate was 82.9%, 63.1%, and 32.1% at 3, 6, and 12 months postoperatively, respectively. Endoscopic re-intervention was performed in 14 patients, whereas 10 underwent percutaneous drainage. Conclusions: Large cell-type stents for endoscopic bilateral stent-in-stent placement had acceptable functional success and stent patency when technically successful. However, the technical difficulty associated with the entanglement of the second stent delivery sheath in the hook-cross-type vertex of the first stent may preclude large cell-type stents from being considered as a dedicated standard tool for stent-in-stent placement.

• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.372-380
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• 2009

After supercritical water treatment of poplar wood meals (passed through 60 mesh) for 60s between 325 and $425^{\circ}C$ at the fixed pressure at $220{\pm}10atm$, some solid residues were present in the degradation products. They mainly consisted of chemically modified lignin and fibrous materials. Glucose and xylose were identified as main sugar components of fibrous materials, and the highest ratio of glucose/xylose was achieved at the highest reaction temperature. As reaction temperature was elevated, the portion of fibrous materials decreased in the solid residues, while lignin was further accumulated. The H : G : S ratio of lignin in solid residues was estimated by analytical pyrolysis. Irrespective of reaction temperatures, the H:G:S ratios were not significantly changed in the lignin in solid residues. Compared to poplar milled wood lignin (MWL), it was remarkable that H type monomers were further lowered, while portion of S type monomers increased. The amount of G type monomers were relative stable. In presence of HCl catalyst, lowering H type as well as enhancing S type was further distinguishable. According to the result of nitrobenzene oxidation (NBO), ca. 265 mg of vanillin and syringaldehyde was yielded from poplar MWL as main products. However, remarkably reduced amount of NBO products were determined from solid residues by raising operating temperature as well as by the addition of HCl catalyst. These results strongly indicate that $\beta$-O-4 linkage could be easily cleaved during supercritical water treatment, so that the lignins in the solid residues seem to be condensed phenol polymers, which are mainly formed by carbon-carbon linkages rather than $\beta$-O-4 linkage.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.4
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• pp.255-267
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• 2004

This study was conducted in order to improvement of fishing gear and fishing operating system for anchovy boat seine by bag net A-type and B-type was attached with half size modified nets. Field experiments were carried out observe geometry of nets by catcher boats. The obtained results are summarized as follows : The actual ratio of net opening in each part of the half size modified nets was increased from fore part to back part of the nets as shown the smallest value about 20% in wing net and the biggest value about 110% in bag net. In addition, vertical net opening of B-type net as measured as 10.9~11.8m in fore bag net and 5.8~8.0m in after bag net were 1~2m greater than 9.0~13.6m of A-type one, and 2~3m less than 9.3~10.4m of A-type one, respectively. Vertical net opening of half size modified net was shown as less variation of towing depth from wing net to inside wing net than those of traditional nets due to stable vertical performance. The mesh distortion or drift and variation of vertical net opening were decreased by improvement of bag nets in order to minimized shape of net pocket phenomenon whenever towing speed is slow. Bag net B-Type attached with dual flapper was shown as less variation in width of bag net and less escapement of anchovy.

• Journal of Life Science
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• v.22 no.8
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• pp.1092-1098
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• 2012

This study was carried out to discover the skin wrinkle reducing components in the seeds of Arctium lappa. The isolation of a methylene chloride-soluble fraction of 70% ethanol extract from the seeds of Arctium lappa using a procollagen type-1 synthesis and MMP-1 activity resulted in the isolation and identification of four lignin compounds: arctiin, arctigenin, matairesinol, and diarctigenin. All structures were confirmed via NMR and MS spectroscopic data. To determine cell viability and procollagen type-1 synthesis, human dermal fibroblasts were treated with 10-100 ${\mu}M$. As a result, none of the four compounds showed cytotoxicity up to 50 ${\mu}M$. We also investigated their procollagen type-1 synthesis and MMP-1 inhibition activity and found that arctiin had the highest activity in terms of both procollagen synthesis and MMP-1 inhibition among all four compounds. Putting all the data together, we suggest that arctiin be used in cosmetics as an anti-wrinkle material.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.6
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• pp.601-606
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• 2013

3D scanning is a technique to measure the 3D shape information of the object. Shape information obtained by 3D scanning is expressed either as point cloud or as polygon mesh type data that can be widely used in various areas such as reverse engineering and quality inspection. 3D scanning should be performed as accurate as possible since the scanned data is highly required to detect the features on an object in order to scan the shape of the object more precisely. In this study, we propose the method on finding the location of feature more accurately, based on the extended Biplane SNAKE with global optimization. In each iteration, we project the feature lines obtained by the extended Biplane SNAKE into each image plane and move the feature lines to the features on each image. We have applied this approach to real models to verify the proposed optimization algorithm.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.3
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• pp.293-301
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• 2007

We present a new global-local analysis with the aid of MLS(Moving Least Square) variable-node finite elements which can possess an arbitrary number of nodes on element master domain. It enables us to connect one finite element with a few finite elements without complex remeshing. Compared to other type global-local analysis, it does not require any superimposed mesh or need not solve the equilibrium equation twice. To demonstrate the performance of the proposed scheme, we will show several examples in relation to capturing highly local stress field using global-local analysis.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.1
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• pp.9-15
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• 2020

The 'field-effect' underlies the operation of most conventional electronic devices. However, effective control and implementation of the field-effect in semiconductor devices are limited due to screening of the electric-field by conducting electrodes. Thus far, the electronic devices have necessarily been designed to avoid or minimize the electric-field screening effect. As an alternative approach to this, a new type of conducting electrodes which would be transparent to both visible light and electric-field while being electrically conductive have been developed. Here, we define these electrodes as 'electric-field transparent electrodes' and provide a review on related work. Particular attention is paid to the material selection and design strategies to enhance the electric-field transparency of the electrodes while maintaining good electrical conductivity and optical transparency. We then introduce potential applications of the electric-field transparent electrodes in electronic and optoelectronic devices.