• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.656-661
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• 2009

In this study, theoretical analysis and evaluation tests were performed to assess the pipe stability against compaction equipments and vehicle loads when conventional construction criteria for pre-insulation heating pipes are applied and the alternative material, crushed sand, are used for backfills. The research outcomes shows that (1) the conventional code criteria for pre-insulated heating pipes is well established to support compaction equipments and vehicle loads, (2) the crushed sands as an alternative is usable as backfill materials for pre-insulated heating pipes based on the suitability evaluations of various types of pipes, and (3) the crushed sand agree well with the design consideration of pre-insulated heating pipes construction in the points of economical efficiency and construction criteria.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.2303-2304
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• 2008

It is believed that the pre-flashover phenomena would play a very important role in the procedure of the flashover in the interface between the insulators and vacuum. This paper is mainly concerned on the pre-flashover phenomena of Alumina insulators in vacuum. There are 24 different types of alumina insulators were tested with a 0.7/4 ${\mu}s$ pulsed voltage under a $1{\times}10^{-4}Pa$ vacuum. The observed pre-flashover phenomena were classified and the pre-flashover characteristics were concluded. It is useful to study further on the flashover mechanism in vacuum.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.2020-2022
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• 2002

SiC direct bonding technology is very attractive for both SiCOI(SiC-on-insulator) electric devices and SiC-MEMS fileds because of its application possibility in harsh environements. This paper presents on pre-bonding according to HF pre-treatment conditions in SiC wafer direct bonding using PECVD oxide. The PECVD oxide was characterized by XPS and AFM, respectively. The characteristics of bonded sample were measured under different bonding conditions of HF concentration and applied pressure, respectively. The bonding strength was evaluated by tensile strength method. Components existed in the interlayer were analyzed by using FT-IR. The bond strength depends on the HF pre-treatment condition before pre-bonding (Min : 5.3 kgf/$cm^2{\sim}$ Max : 15.5 kgf/$cm^2$).

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.35.1-35.1
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• 2005

• 기계저널
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• 제23권6호
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• pp.419-426
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• 1983

본 고에서는 첫째, Pre-CHF영역에서의 열전달 및 비등급기에 여러 상관식이 제안되었으나 열수력현상의 복잡성 때문에 완전한 이론해는 구해져 있지 않다. 둘째, 각 상관식은 그 예측에 있어서 정량적으로 많은 차이가 있다. 셋째, 상관식의 적용범위가 한정되어 있기 때문에 사용 상관식의 선택을 조건에 따라 신중히 하여야 한다.

• 대한기계학회논문집
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• 제6권2호
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• pp.133-139
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• 1982

One of factors that affect combustion in the cylinder of the engine is to keep a greater energy in the ignition system to minimize pollutant emissions and to increase its performance of the low temperature. This paper reviews theoretically the state and input variables of the ignition system from the state transition equation. Effects on characteristics of the system such as primary current, secondary available voltage and spark duration by reducing the pre-resistance from 3.5 to 0 ohm in 12V system is experimentally investigated when the ignition coil has a primary resistance of 1.5 ohms ad the dwell angle of the breaker point is 43.2 degrees (0.75 radian). Advantages and limitations for using the low resistance of the primary circuit are also presented to optimize the performance of the ignition system with the breaker point.

• 대한기계학회논문집B
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• 제32권1호
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• pp.70-77
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• 2008

A pre-processing program based on the OOP(object-oriented programming) concept has been developed. The program consists of the input of a 2D or 3D flow problem to a CFD program by means of an user-friendly interface and the subsequent transformation of this input into a form suitable for the solver(PowerCFD) using unstructured cell-centered method. User-friendly GUI(graphic user interface) has been built on the base of MFC(Microsoft Foundation Class). The program is organized as modules by classes based on VTK(Visualization ToolKit)-library, and these classes are made to function through inheritance and cooperation which is an important and valuable concept of object-oriented programming. The major functions of this program are introduced and demonstrated, which include mesh generation, boundary settings, solver settings, generation of grid connectivity and geometric data etc.

• 전기학회논문지
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• 제56권5호
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• pp.905-909
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• 2007

Crystalline and micro-structural characteristics of ZnO thin films which were deposited on p-Si(100) with cooling naturally down of pre-heated substrate during RF magnetron sputter deposition, were investigated by XRD and SEM in this paper. The film which was prepared on the substrate which was pre-heated to $400^{\circ}C$ before deposition and then cooled naturally down during deposition, showed the most outstanding c-axis preferred orientation. The ZnO thin film having the best crystalline result were applied to SMR type FBAR device and resonance properties of the device were investigated by network analyzer. It showed that resonance frequency was 2.05 GHz, return loss was -30.64 dB, quality factor was 3169 and electromechanical coupling factor was 0.4 %. This deposition method would be very useful for application of surface acoustic wave filter or film bulk acoustic wave resonator.

• 한국전기전자재료학회논문지
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• 제14권10호
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• pp.779-784
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• 2001

In this work, we studied the characteristics of nitride films for the optimization of PMD(pro-metal dielectric) linear process, which can be applied to the recent semiconductor manufacturing process. We split the deposit condition of nitride films into four parts such as PO(protect overcoat) nitride, baseline, low hydrogen and high stress and low hydrogen, respectively. We tried to find out correlation between BPSG deposition and densification. In order to analyze the changes of Si-H and Si-NH-Si bonding density, we used FTIR area method. We also investigated the crack generation on wafer edge after BPSG densification, and the changes of nitride film stress as a function of RF power variation to judge whether the deposited films.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.362-363
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• 2006

Ozonized DI water was supplied to make alkaline cleaning solutions to replace SCI chemicals in a bath with and without recirculation. With recirculation, low dissolved ozone and low pH cause lower particle removal efficiency (PRE) of 75%. However, direct supply of ozonized water with $NH_4OH$ to a bath without recirculation resulted in higher PRE over 93 %.