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Effect of Squeeze Cast Process Parameters on Fluidity of Hypereutectic Al-Si Alloy

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Journal of Materials Science & Technology 2008年第1期24卷 7-11页

作者： Jong-Kyu Baek Hae-Wook kwon School of Materials Science and Engineering Yeungnam University Gyeongsan 712-749 Korea

The effects of processing variables on the fluidity of hypereutectic Al-Si alloy melt during squeeze casting were *** maximum fluidity of Al-16.0%Si alloy during squeeze casting was obtained under the applied pressure of 30 *** fluidity increased with *** fluidity increased with silicon content in the range from 12.0% to 20.0%.That was decreased respectively by eutectic modification and primary silicon refinement.

关键词： Squeeze casting Al-alloy Fluidity Melt treatment

Reconstruction of Rabbit Corneal Layer Composed of Corneal Fibroblasts and Corneal Epithelium on the Lyophilized Amniotic Membrane

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Chemical Research in Chinese Universities 2006年第2期22卷 150-156页

作者： AHN Jae-il JANG In-keun YOON Mun-young SEO Young-kwon YOON Hee-hun KIN Jae-chan SONG Kye-yong YANG Eun-kyung PARK Jung-keug Department of Chemical and Biochemical Engineering Dongguk University Seoul Korea Department of Ophthalmology Chung-Ang University Hospital Seoul Korea Department of Pathology College of Medicine Chung-Ang University Seoul Korea R & D Center Bioland Ltd. Chun-An Korea

Many researchers have employed the cryopreserved amniotic membrane（CAM） and corneal epithelial cells in the treatment of a severely damaged burned cornea, with corneal epithelial cells cultured on an amniotic membrane （AM）. The lyophilized amniotic membrane（LAM） has a higher graft take and a longer shelf life; it is easier to store and safer because of gamma irradiation. Two Teflon rings（ Ahn＇s supporter） were made for culturing the cells on the LAM, and were then used to support the LAM. To reconstruct a corneal layer composed of corneal fibroblasts and epithelium, the corneal fibroblasts were first cultivated on the stromal side of LAM for five days, foUowed by epithelial cells culture on the epithelial side, by using the air-liquid interface culture. The reconstructed corneal layer composed of corneal fibroblasts and corneal epithelial cells has a much healthier basal layer of corneal epithelium than the reconstructed corneal epithelium, which was got by using only corneal epithelial cells, and resembles the epithelium of normal corneas, without the horny layer. Thus, the reconstruction of the corneal layer by using a LAM is considered to be a good in vitro model, not only for its application in toxicological test kits, but also for transplantation in patients with a severely damaged cornea.

关键词： Lyophilized amniotic membrane Corneal layer Corneal fibroblast Corneal epithelium

Decomposing Composite Changes for Code Review and Regression Test Selection in Evolving Software

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Journal of Computer Science & Technology 2019年第2期34卷 416-436页

作者： Bo Guo Young-Woo kwon Myoungkyu Song Department of Global Operations PayPal Omaha Nebraska 68128 U.S.A. School of Computer Science and Engineering Kyungpook National University Daegu 702-701 South Korea Department of Computer Science University of Nebraska at Omaha Omaha 68128 U.S.A.

Inspecting and testing code changes typically require a significant amount of developer *** a system evolves,developers often create composite changes by mixing multiple development issues,as opposed to addressing one independent issue—an atomic *** composite changes often becomes time-consuming and *** test unrelated edits on composite changes,rerunning all regression tests may require excessive *** address the problem,we present an interactive technique for change decomposition to support code reviews and regression test selection,called *** a developer specifies code change within a diff patch,ChgCutter partitions composite changes into a set of related atomic changes,which is more cohesive and self-contained regarding the issue being *** composite change inspection,it generates an intermediate program version that only includes a related change subset using program dependence *** cost reduction during regression testing,it safely selects only affected tests responsible for changes to an intermediate *** the evaluation,we apply ChgCutter to 28 composite changes in four open source *** partitions these changes with 95.7% accuracy,while selecting affected tests with 89.0% *** conduct a user study with professional software engineers at PayPal and find that ChgCutter is helpful in understanding and validating composite changes,scaling to industry projects.

关键词： software maintenance and evolution code review test selection program slicing

Estimation of exposure dose for decontamination workers from contaminated soil at a nuclear decommissioning site in Korea

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辐射防护 2020年第6期40卷 619-624页

作者： Sohyeon Lee Dong-kwon Keum Hyo-Joon Jeong In Jun Kwang-Muk Lim and yong-Ho Choi Korea Atomic Energy Research Institute 989-111 Daedeok-daeroYuseong-guDaejeonRepublic of Korea

Assessment of the exposure dose for workers is crucial to protecting workers from the radiological *** preliminary study estimates the potential radiological exposure for a soil remediation worker at a nuclear decommissioning site contaminated with Cs-137 in Korea,and then calculates the maximum workable soil concentration to comply with the occupational dose constraint of 20 mSv per *** Korean characteristic data,detailed exposure scenarios for workers by the type of work,and relevant exposure pathways were used in the dose *** a result,the most severe exposure-induced work type was identified as the excavator operation with an annual individual dose of 5.92×10^-5 mSv for a unit concentration of soil,from which the derived maximum workable soil concentration was 3.38×105 Bq/***,dose contribution by each exposure pathway was found to be decreased in the following order:external radiation exposure,soil ingestion,dust inhalation,and skin *** results of this study are expected to be used effectively to optimize radiation protection for workers and establish appropriate work procedures for future site remediation.

关键词： nuclear decommissioning decontamination site remediation dose assessment radiological risk radiological environmental impact assessment radiation protection

An XPath-based OWL storage model for effective ontology management in Semantic Web environment

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第6期10卷 843-857页

作者： Jinhyung KIM Dongwon JEONG Doo-kwon BAIK Department of Computer Science and Engineering Korea University Department of Informatics and Statistics Kunsan National University

With the rapid growth of the Web, the volume of information on the Web is increasing exponentially. However, information on the current Web is only understandable to humans, and this makes precise information retrieval difficult. To solve this problem, the Semantic Web was proposed. We must use ontology languages that can assign data the semantics for realizing the Semantic Web. One of the representative ontology languages is the Web ontology language OWL, adopted as a recommen-dation by the World-Wide Web Consortium (W3C). OWL includes hierarchical structural information between classes or prop-erties. Therefore, an efficient OWL storage model that considers a hierarchical structure for effective information retrieval on the Semantic Web is required. In this paper we suggest an XPath-based OWL storage (XPOS) model, which includes hierarchical information between classes or properties in XPath form, and enables intuitive and effective information retrieval. Also, we show the comparative evaluation results for the performance of the XPOS model, Sesame, and the XML file system-based storage (XFSS) model, in terms of query processing and ontology updating.

关键词： XPath Web ontology language Hierarchical structure Ontology storage Semantic Web

A Reprocessing Model for Complete Execution of RFID Access Operations on Tag Memory

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Journal of Computer Science & Technology 2012年第1期27卷 213-224页

作者： Wooseok Ryu Bonghee Hong Joonho kwon Ge Yu Department of Computer Engineering Pusan National UniversityBusan 609-735Korea Institute of Logistics Information Technology Pusan National UniversityBusan 609-735Korea School of Information Science and Engineering Northeastern UniversityShenyang 110004China

This paper investigates the problem of inconsistent states of radio frequency identification （RFID） tag data caused by incomplete execution of read/write operations during access to RFID tag memory. Passive RFID tags require RF communication to access memory data. This study is motivated by the volatility of RF communication, where instability is caused by intermittent connections and uncertain communication. If a given tag disappears from the communication area of the reader during the reading or writing of tag data, the operation is incomplete, resulting in an inconsistent state of tag data. To avoid this inconsistency, it is necessary to ensure that any operations on tag memory are completed. In this paper, we propose an asynchronous reprocessing model for finalizing any incomplete execution of read/write operations to remove inconsistent states. The basic idea is to resume incomplete operations autonomously by detecting a tag＇s re-observation from any reader. To achieve this, we present a concurrency control mechanism based on continuous query processing that enables the suspended tag operations to be re-executed. The performance study shows that our model improves the number of successful operations considerably in addition to suppressing inconsistent data access completely.

关键词： asynchronous reprocessing concurrency control continuous query RFID tag access operation

Small-scale multi-axial hybrid simulation of a shear-critical reinforced concrete frame

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Earthquake Engineering and Engineering Vibration 2017年第4期16卷 727-743页

作者： Vahid Sadeghian Oh-Sung kwon Frank Vecchio Department of Civil Engineering University of Toronto35 St.George St.TorontoONCanada

This study presents a numerical multi-scale simulation framework which is extended to accommodate hybrid simulation （numerical-experimental integration）. The framework is enhanced with a standardized data exchange format and connected to a generalized controller interface program which facilitates communication with various types of laboratory equipment and testing configurations. A small-scale experimental program was conducted using a six degree-of-freedom hydraulic testing equipment to verify the proposed framework and provide additional data for small-scale testing of shear- critical reinforced concrete structures. The specimens were tested in a multi-axial hybrid simulation manner under a reversed cyclic loading condition simulating earthquake forces. The physical models were 1/3.23-scale representations of a beam and two columns. A mixed-type modelling technique was employed to analyze the remainder of the structures. The hybrid simulation results were compared against those obtained from a large-scale test and finite element analyses. The study found that if precautions are taken in preparing model materials and if the shear-related mechanisms are accurately considered in the numerical model, small-scale hybrid simulations can adequately simulate the behaviour of shear-critical structures. Although the findings of the study are promising, to draw general conclusions additional test data are required.

关键词： hybrid simulation small-scale testing reinforced concrete structures, shear behaviour multi-scale modelling

Suppression of gold nanoparticle agglomeration and its separation via nylon membranes

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Chinese Journal of Chemical Engineering 2017年第7期25卷 931-937页

作者： Ayyavoo Jayalakshmi In-Chul Kim Young-Nam kwon School of Urban and Environmental Engineering Ulsan National Institute of Sdence and TechnologyUlsan 689-798Korea KIST-UNIST UIsan Center for Convergent Materials UNIST(Ulsan National Institute of Science and Technology)Korea Environment and Resources Research Center Korea Research Institute Chemical TechnologyDaejeon 305-606Korea

Use of ultraporous nylon membrane is one of the most widely employed techniques for removal of hard and soft nanoparticles in the semiconductor industry, and the accurate determination of membrane pore size is necessary in order to avoid manufacturing defects caused by contamination. The gold nanoparticle has several benefits for the evaluation of polymeric membranes; however, the nanoparticles agglomerate easily on the nylon membrane and make it difficult to evaluate the membrane precisely. The properties of 2-amino-2-hydroxymethyl-1,3-propanediol(ADP) ligand in gold nanoparticle solution were systematically investigated, and ADP was utilized for improved evaluation of the nylon membranes. Nylon membrane used in this study was prepared by phase inversion techniques. Ultrathin dense layer on top of the membrane surface and Darcy structures in the microporous membrane support were observed. The gold particle rejection was carried out at various p H values from 4 to14 and higher rejection was observed at p H 4 and 8. The suppression of gold colloid agglomeration using ADP and monodispersity of gold colloids was also analyzed by confocal laser scanning microscopy(CLSM), transmission electron microscopy(TEM), and scanning electron microscopy(SEM). van der Waals interaction energy of the particles was reduced in the addition of ADP. The presence of ADP ligand in the gold solutions prevented the agglomeration of gold nanoparticles and reduced the adsorption of the particles on the nylon membrane surface,leading to precise evaluation of membrane pore sizes.

关键词： Particle size Electron microscopy Gold colloid flock Semiconductor

VQT:value cardinality and query pattern based R-schema to XML schema translation with implicit referential integrity

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第12期9卷 1694-1707页

作者： Jinhyung KIM Dongwon JEONG Doo-kwon BAIK Department of Computer Science and Engineering Korea UniversitySeoul 136-713Korea Department of Informatics and Statistics Kunsan National UniversityKunsan 573-701Korea

In this paper,we propose a new relational schema (R-schema) to XML schema translation algorithm, VQT, which analyzes the value cardinality and user query patterns and extracts the implicit referential integrities by using the cardinality property of foreign key constraints between columns and the equi-join characteristic in user queries. The VQT algorithm can apply the extracted implied referential integrity relation information to the R-schema and create an XML schema as the final result. Therefore, the VQT algorithm prevents the R-schema from being incorrectly converted into the XML schema, and it richly and powerfully represents all the information in the R-schema by creating an XML schema as the translation result on behalf of the XML DTD.

关键词： Value cardinality Query pattern Relational schema XML schema Implicit referential integrity relations Explicit referential integrity