• Journal of Communications and Networks
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• 제7권3호
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• pp.377-384
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• 2005

The purpose of this research is to develop and evaluate a traffic engineering architecture that uses local state information. This architecture is applied to an Internet protocol radio access network (RAN) that uses multi-protocol label switching (MPLS) and differentiated services to support mobile hosts. We assume mobility support is provided by a protocol such as the hierarchical mobile Internet protocol. The traffic engineering architecture is router based-meaning that routers on the edges of the network make the decisions onto which paths to place admitted traffic. We propose an algorithm that supports the architecture and uses local network state in order to function. The goal of the architecture is to provide an inexpensive and fast method to reduce network congestion while increasing the quality of service (QoS) level when compared to traditional routing and traffic engineering techniques. We use a number of different mobility scenarios and a mix of different types of traffic to evaluate our architecture and algorithm. We use the network simulator ns-2 as the core of our simulation environment. Around this core we built a system of pre-simulation, during simulation, and post-processing software that enabled us to simulate our traffic engineering architecture with only very minimal changes to the core ns-2 software. Our simulation environment supports a number of different mobility scenarios and a mix of different types of traffic to evaluate our architecture and algorithm.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.575-580
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• 2014

We uniformly coated Eu(III)- and Tb(III)-doped yttrium oxide onto the surface of $SiO_2$ spheres and then characterized them by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction crystallography and UV-Visible absorption. 2D and 3D photoluminescence image map profiles were reported for the core-shell type structure. Red emission peaks of Eu(III) were observed between 580 to 730 nm and assigned to $^5D_0{\rightarrow}^7F_J$ (J = 0 - 4) transitions. The green emission peaks of Tb(III) between 450 and 650 nm were attributed to the $^5D_4{\rightarrow}^7F_J$ (J = 6, 5, 4, 3) transitions. For annealed samples, Eu(III) ions were embedded at a $C_2$ symmetry site in $Y_2O_3$, which was accompanied by an increase in luminescence intensity and redness, while Tb(III) was changed to Tb(IV), which resulted in no green emission.

• 한국전기전자재료학회논문지
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• 제24권3호
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• pp.219-223
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• 2011

Rhenium-Iridium(Re-Ir) thin films were deposited onto the tungsten carbide(WC) molding core by sputtering system. The Re-Ir films were prepared by multi-target sputtering with iridium, rhenium and chromium as the sources. Argon and nitrogen were inlet into the chamber to be the plasma and reactive gases. The Re-Ir thin films were prepared with targets having atomic percent of 3:7 and the Re-Ir thin films were formed with 240 nm thickness. The Re-Ir thin films on tungsten carbide molding core were analyzed by scanning electron microscope(SEM) and surface roughness. Also, adhesion strength and coefficient friction of Re-Ir thin film were examined. The Re-Ir coating technique has been intensive efforts in the field of coating process because the coating technique and process have been their feature, like hardness, high elasticity, abrasion resistance and mechanical stability and also have been applied widely the industrial and biomedical areas. In this report, tungsten carbide(WC) molding core was manufactures using high performance precision machining and the efforts of Re-Ir coating on the surface roughness.

• 한국정보과학회 언어공학연구회:학술대회논문집(한글 및 한국어 정보처리)
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• 한국정보과학회언어공학연구회 2009년도 제21회 한글 및 한국어 정보처리 학술대회
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• pp.111-115
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• 2009

현재 Open API는 프로그램 개발 및 정보의 제공 등 다양한 방향에서 많이 활용 되고 있다. Open API는 개발된 기술을 웹으로 공개하여 네트워크가 연결된 곳이라면 어디서든지 그 기술을 활용할 수 있다. 잘 개발된 Open API는 매쉬업을 통해 또 다른 기술과 합쳐 새로운 서비스를 개발하는 등 그 활용빈도가 높다. 이미 개발된 기술을 활용할 수 있어서 개발 속도가 단축되고 새로운 서비스를 개발하면서 기존의 부족한 부분을 합쳐 더욱 창의적인 정보 제공이 가능하다. 이러한 Open API의 특성을 이용하여 시맨틱 기술 개발을 지원할 수 있으며, 개발 시간 단축 및 관계 설정, 온톨로지 제공 등을 네트워크를 통해 사용자들에게 제공하고 활용할 수 있는 방법을 제시한다. 시맨틱 기술은 사람이 글을 읽고 의미를 이해하는 것처럼 컴퓨터가 이해할 수 있는 언어와 규칙들을 정해 놓아 컴퓨터 사이의 의사소통을 가능하게 하는 지능형 기술이다. 이런 시맨틱 기술 개발을 지원하기 위하여 Open API를 통해 온톨로지의 개념 및 속성, 관계 설정, 코퍼스 등을 제공하기 하기 위해 CoreOnto API라는 것을 구축했다. CoreOnto API는 네트워크에서 사용할 수 있는 Open API로 세가지의 큰 형태의 Open API를 제공하고 있다. 첫 번째, 온톨로지에 대한 클래스, 속성, 관계를 제공하는 APIs, 두 번째, 트리플(두개의 용어가 어떤 관계인지를 표현한 형태로 구성(용어1, 관계, 용어2)) 생성 및 구축된 트리플을 검색할 수 APIs, 세 번째, 온톨로지를 생성하기 위해 필요한 자원(온톨로지 명, 개체명, 관계, 코퍼스 등)을 제공하는 APIs로 구성했다. 이상과 같이 시맨틱 기술 개발을 지원하기 위한 큰 형태의 세 가지 APIs를 구축하는 방법과 APIs의 활용, 그리고 서비스를 테스트한 결과를 제시한다.

• Nuclear Engineering and Technology
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• 제49권7호
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• pp.1547-1554
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• 2017

VESTA (Verification of Ex-vessel corium STAbilization) and VESTA-S (-small) test facilities were constructed at the Korea Atomic Energy Research Institute in 2010 to perform various corium melt experiments. Since then, several tests have been performed for the verification of an ex-vessel core catcher design for the EU-APR1400. Ablation tests of an impinging $ZrO_2$ melt jet on a sacrificial material were performed to investigate the ablation characteristics. $ZrO_2$ melt in an amount of 65-70 kg was discharged onto a sacrificial material through a well-designed nozzle, after which the ablation depths were measured. Interaction tests between the metallic melt and sacrificial material were performed to investigate the interaction kinetics of the sacrificial material. Two types of melt were used: one is a metallic corium melt with Fe 46%, U 31%, Zr 16%, and Cr 7% (maximum possible content of U and Zr for C-40), and the other is a stainless steel (SUS304) melt. Metallic melt in an amount of 1.5-2.0 kg was delivered onto the sacrificial material, and the ablation depths were measured. Penetration tube failure tests were performed for an APR1400 equipped with 61 in-core instrumentation penetration nozzles and extended tubes at the reactor lower vessel. $ZrO_2$ melt was generated in a melting crucible and delivered down into an interaction crucible where the test specimen is installed. To evaluate the tube ejection mechanism, temperature distributions of the reactor bottom head and in-core instrumentation penetration were measured by a series of thermocouples embedded along the specimen. In addition, lower vessel failure tests for the Fukushima Daiichi nuclear power plant are being performed. As a first step, the configuration of the molten core in the plant was investigated by a melting and solidification experiment. Approximately 5 kg of a mixture, whose composition in terms of weight is $UO_2$ 60%, Zr 10%, $ZrO_2$ 15%, SUS304 14%, and $B_4C$ 1%, was melted in a cold crucible using an induction heating technique.

• Bulletin of the Korean Chemical Society
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• 제27권9호
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• pp.1341-1345
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• 2006

An electrostatic interaction is responsible for the attachment of gold seeds of 1-3 nm onto APTMS (3-aminopropyl trimethoxysilane)-coated silica cores in the formation of gold clusters. A surface plasmon resonance and morphology of gold clusters were significantly affected by the pH of gold colloids prepared by THPC reducing agent. Gold colloids of alkaline pH induced the heterogeneous deposition of gold seeds onto the silica nanoparticles, probably due to the continuous reduction of residual gold ions during the attachment process. Gold colloids of acidic pH induced the monodisperse deposition of gold seeds, consequently leading to the formation of smooth gold layer on the silica nanoparticles surface. The gold nanoshells (core radius = 80 nm) prepared by gold colloids of pH 3.1 exhibited the more red-shift and relatively stronger intensity of plasmon absorption bands, compared with gold nanoshells prepared by alkaline gold colloids of pH 9.7.

• 지구물리와물리탐사
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• 제18권3호
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• pp.105-114
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• 2015

상온 상습 환경에서 수포화 암석코어의 전기비저항을 장시간 모니터링 할 수 있는 장치를 구현하였다. 양쪽 금속망 전극에 덧댄 종이필터와 암석코어를 감싼 열수축튜브의 상부 중앙 외피면에 3-채널 펌프로 물을 충분히 공급하면서 전기저항을 측정하면 암석코어의 수포화 상태를 유지하면서 일주일 이상 전기비저항을 모니터링 할 수 있다. 이 장치를 이용하여 흑운모 편마암, 안산암질 응회암, 셰일의 3종류 암석코어의 수포화 전기저항을 9일간 모니터링 한 결과 다음과 같은 2가지 가설을 제시할 수 있었다. 즉, 전기비저항 온도계수의 수렴 속도는 열물성과 관련이 있을 것이라는 것과 건조 저항을 수포화 때의 평균 저항으로 나눈 건조/수포화 저항비는 유효공극률과 상관될 것이라는 것이다. 실제로, 3가지 암석의 건조/수포화 저항비는 각각 48, 705, 2로 나타났고 이때 각각의 유효공극률은 3.7%, 3.3%, 13.0%이었다.

• 대한치과기공학회지
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• 제42권3호
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• pp.213-219
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• 2020

Purpose: This study aimed to identify the impact of physical surface roughing with a polishing tool onto the pre-sintering yttria-stabilized tetragonal zirconia polycrystals (TZP) core and liner treatment for chemical bonding on the bond strength of TZP core and veneering ceramic. Methods: Overall, 80 specimens were classified into two groups (non-liner, NL; and usingliner, UL ) depending on the use of liner, and these two groups were then subclassified into four groups depending on the polishing tool used. (1) Non-liner groups: NS, non-liner+stone point; NC, non-liner+carbide bur; NP, non-liner+paper cone point; NT, non-liner+silicon point. (2) Using-liner groups: US, using-liner+stone point; UC, using-liner+carbide bur; UP, usingliner+paper cone point; UT, using-liner+silicon point. The pre-sintering surface roughing values and shapes were observed, and after burning up the veneering ceramic, the shear bond strength was measured using a universal testing machine. For significance testing, a one-way analysis of variance and Tukey's multiple comparison test were conducted. An optical microscope was used to observe the fracture plane, and the following results were obtained. Results: Surface roughness NP (4.09±0.51 ㎛) represented a higher value than other groups (p<0.001). In shear bond strength, NS (35.21±1.44 MPa) of the NL group showed the highest bond strength (p<0.001). The UL group did not show a statistically significant difference between groups (p=0.612). Conclusion: Our study findings reveal that the bond strength of TZP core and veneering ceramic was improved by pre-sintering physical surface treatment than by chemical bonding with liner surface treatment.

• Journal of Ceramic Processing Research
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• 제13권spc2호
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• pp.328-331
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• 2012

With the recent development of super-precision optical instruments, camera modules for devices, such as portable terminals and digital camera lenses, are increasingly being used. Since an optical lens is usually produced by high-temperature compression molding methods using tungsten carbide (WC) alloy molding cores, it is necessary to develop and study technology for super-precision processing of molding cores and coatings for the core surface. In this study, Rhenium-Iridium (Re-Ir) thin films were deposited onto a WC molding core using a sputtering system. The Re-Ir thin films were prepared by a multi-target sputtering technique, using iridium, rhenium, and chromium as the sources. Argon and nitrogen were introduced through an inlet into the chamber to be the plasma and reactive gases. The Re-Ir thin films were prepared with targets having a composition ratio of 30 : 70, and the Re-Ir thin films were formed with a 240 nm thickness. Re-Ir thin films on WC molding core were analyzed by scanning electron microscope (SEM), atomic force microscope (AFM), and Ra (the arithmetical average surface roughness). Also, adhesion strength and coefficient friction of Re-Ir thin films were examined. The Re-Ir coating technique has received intensive attention in the coating processes field because of promising features, such as hardness, high elasticity, abrasion resistance and mechanical stability that result from the process. Re-Ir coating technique has also been applied widely in industrial and biomedical applications. In this study, WC molding core was manufactured, using high-performance precision machining and the effects of the Re-Ir coating on the surface roughness.

• Korean Chemical Engineering Research
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• 제45권2호
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• pp.166-171
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• 2007

칼슘 이온에 의해 젤화되는 알지네이트를 내부가 고상인 비드와 내부가 액상인 캡슐 형태로 각각 만들어 납이온 흡착 특성을 비교하여 보았다. 흡착 키네틱과 흡착 등온선 분석을 통해 칼슘-알지네이트 비드와 캡슐의 흡착 특성 차이를 pH 및 경화 시간에 따른 변화, 흡착시 칼슘 이온 방출량의 모니터링을 통해 검토하였다. 비드와 캡슐의 구조적 차이에 상관없이 두 흡착제 모두 표면착화(surface complexation)와 이온교환(ion exchange) 메커니즘에 의해 납 이온을 흡착하였고, 흡착량에 상관없이 두 메커니즘 간의 비율은 유사하였다. 납이온 흡착에 대한 pH 의존성은 비드와 캡슐이 유사하였으며, 이는 두 흡착제에 존재하는 표면 작용기가 유사함을 의미한다. 반면에 흡착 키네틱 분석에서는 캡슐에 비해 비드에서의 납이온 흡착 속도가 느렸으며, 흡착 등온선 분석에서 얻은 납이온의 최대 흡착량($Q_{max}$)은 알지네 이트 비드가 캡슐의 약 49% 정도로 나타났다. 이러한 납이온 흡착 거동의 차이는 비드와 캡슐 간의 구조적 차이에 기인한 것으로, 알지네이트 비드는 확산 저항에 의해 상대적으로 느린 흡착 속도 및 단위 무게당 적은 흡착량을 보이는 것으로 판단된다.