• Title/Summary/Keyword: Smoother

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Si Anisotropic Etching Characteristics of TMAH/IPA (TMAH/IPA의 실리콘 이방성 식각특성)

  • 정귀상;박진성;최영규
    • Electrical & Electronic Materials
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    • v.10 no.5
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    • pp.481-486
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    • 1997
  • This paper describes the anisotropic etching characteristics of Si in acqueous TMAH/IPA solutions. The etch rates of (100) oriented Si crystal planes decrease with increasing TMAH concentration and IPA concentration. Etchant concentration and etch temperature have a large effect on hillock density. Hillock density strongly increase with lower TMAH concentration and higher etch temperature. The etched (100) planes are covered by pyramidal-shaped hillocks below TMAH 15 wt.%, but very smooth surface is obtained TMAH 25 wt.%. The addition of IPA to TMAH solution leads to smoother surfaces of sidewalls etched planes. Undercutting ratio of pure TMAH solution is much higher than KOH. But, addition of IPA to TMAh the underrcutting ratio reduces by a factor of 3∼4. Therefore, acqueous TMAH/IPA solution is able to use as anisotropic etchant of Si because of full compability with IC fabrication process.

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How Technology Appropriateness Affects Its Usage and Outcomes : The Korea's National Single Window Experience

  • Kim, Sung Kun;Kim, Chang Bong
    • Journal of Information Technology Applications and Management
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    • v.21 no.4
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    • pp.295-308
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    • 2014
  • Global trading is an intrinsically complex endeavor with a number of parties involved. World-trading related international organizations have suggested that Single Window (SW) be used as a means to make the trading process simpler and smoother. However, since each firm has its own requirements and objectives with SW, yet there is no consensus as to what traits of 'good' Single Window are. This study uses IT appropriateness as a determinant to explain an impact on information systems success. Historically, IS success was understood as multi-dimensional constructs such as use and performance. In this study we propose another dimension, continuance, and investigate the relationships among these outcome constructs.

AFM based Surface Verifications of Pulse Electrochemical Polishing for Various Frequency Conditions (주파수 변화에 따른 AFM 기반의 펄스 전기화학 폴리싱 표면특성 분석)

  • Kim, Young-Bin;Kim, Jong-Tye;Ahn, Dong-Gyu;Park, Jong-Rak;Jeong, Sang-Hwa;Park, Jeong-Woo
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.2
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    • pp.246-251
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    • 2012
  • Pulse electrochemical polishing process has been used to improve mechanical properties such as surface roughness and corrosion resistance on conductive metallic materials. In addition, pulse electrochemical polishing process with various frequency may produce a lustrous, smoother, deburred and cleaned surface on workpiece. The aim of this paper is to study surface characteristics of pulse electrochemical polishing for various frequency conditions using AFM to verify localized surface variation in nanometer scale.

Recent Studies of Laser Metal 3D Deposition with Wire Feeding (와이어 송급 레이저 금속 3차원 적층 연구동향)

  • Kam, Dong-Hyuck;Kim, Young-Min;Kim, Cheolhee
    • Journal of Welding and Joining
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    • v.34 no.1
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    • pp.35-40
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    • 2016
  • Recent developments of Laser metal 3D deposition with wire feeding are reviewed which provide an alternative to powder feeding method. The wire feeding direction, angle and position as well as laser power, wire feeding rate, and deposition speed are found to be key parameters to make quality deposition with high throughput. When compared with the powder feed, the wire feed shows higher material efficiency, higher deposition rate, and smoother surface. Large elongated columnar grains which have epitaxial growth across deposit layers are observed in deposit cross sections. The growth direction is parallel to the thermal gradient during the deposit process. Tensile properties are found to be dependent on the direction due to the anisotropic deposit property. A real-time feedback control is demonstrated to be effective to improve the deposition stability.

Comparison of Nonparametric Function Estimation Methods for Discontinuous Regression Functions

  • Park, Dong-Ryeon
    • The Korean Journal of Applied Statistics
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    • v.23 no.6
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    • pp.1245-1253
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    • 2010
  • There are two main approaches for estimating the discontinuous regression function nonparametrically. One is the direct approach, the other is the indirect approach. The major goal of the two approaches are different. The direct approach focuses on the overall good estimation of the regression function itself, whereas the indirect approach focuses on the good estimation of jump locations. Apparently, the two approaches are quite different in nature. Gijbels et al. (2007) argue that the comparison of two approaches does not make much sense and that it is even difficult to choose an appropriate criterion for comparisons. However, it is obvious that the indirect approach also has the regression curve estimate as the subsidiary result. Therefore it is necessary to verify the appropriateness of the indirect approach as the estimator of the discontinuous regression function itself. Park (2009a) compared the performance of two approaches through a simulation study. In this paper, we consider a more general case and draw some useful conclusions.

A STUDY ON THE ROUGHNESS OF THE VISIBLE LIGHT CURED COMPOSITE RESINS (가시광선(可視光線) 중합형(重合型) 복합(複合)레진의 표면조도(表面粗度)에 관(關)한 연구(硏究))

  • Lee, Myung-Jong
    • Restorative Dentistry and Endodontics
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    • v.16 no.2
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    • pp.197-212
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    • 1991
  • The purpose of this study was to roughness on the polished surface of visible light composite resins and was to observe the polished surfaces under Scanning Electrom Microscope(ISI DS 130 AKASHI Co. JAPAN). The surface roughness tester(Surfcom 700A Seimtsu profilometer Tokyo, Japan) was used to measure roughness of polished surfaces. In this study, 5 brands of visible of composite resins were examined, Pyrofile light bond Anterior Lite fil anterior Photo clearfil anterior & posterior Palfique light Anterior and posterior Silux Anterior. White point, Silicure point, Super snap Sof-Lex medium disk as cutting instrument, and celluloid matrix were used. The results obtained were as follows. 1. The Celluloid matrix produced the smoothest surfaces. 2. The surfaces made by Soflex medium disk was smoother than the surfaces made by any other polishing instruments. 3. The values of surface roughness made by White point, Silicon point and Super snap were similer. 4. Palfique light (AP) visible light composite resin showed the smoothest surface after polishing with Silicone point, Super snap disk and Soflex mediuem disk in all tested materials.

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The Material Distribution by the Ecosystem Modeling in Suyoung Bay (수영만의 생태계모델링에 의한 물질분포)

  • 김동선;조규대
    • Journal of Environmental Science International
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    • v.7 no.6
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    • pp.817-825
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    • 1998
  • A three-dimensional ecosystem model is applied to the Suyoung Bay, located at the southeastern part of Korea, to study of the material distribution in the time scale of several tens days. The model has included of the DIN(Dissolved Inorganic Nitrogen), DIP(Dissolved Inorganic Phosphate), phytoplankton, zooplankton and detritus, and also was coupled with the physical processes. The spatial distribution of chlorophyll-a and primary productivity in the model is determined by the physical and chemical-biological parameters. The horizontal distributions of the DIN, DIP and chlorophyll-a are decreased from the coast to the off-shore, though the nutrients show some more complicated pattern than the chlorophyll-a. The nutrient contents in the off-shore are low, and thus a relatively low productivity(chlorophyll-a) are presented. On the whole, the distribution of the results of model are smoother than the observed ones and some small scale variation in the observed data cannot be reproduced by the model due to the resolution limits of model. However, the basic pattern and the quantitavities has been reproduced by the model well.

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High power 31 level Single Phase AC/DC Converter (대용량 21 레벨 단상 AC/DC 컨버터)

  • 전중함
    • Proceedings of the KIPE Conference
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    • 2000.07a
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    • pp.309-312
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    • 2000
  • Single-phase multi-level AC-DC converter is proposed that is composed of diode bridge and switch. The number of the supply current level is depending on the individual current level of the converter. A converter circuit the number of the level is equal to $\textrm{2}^{M+1}$-1 The proposed circuit has converter with 31 current levels. When the number of current level is increased smoother sinusoidal waveform can be obtained directly and it is possible to control the supply current almost continuously from zero to maximum without step changes of generating high voltage as pulse width modulation switching loss is decreased it has an advantage in large capacity. it is illustrated technique are confirmed the validity and effectiveness through the simulation & experiments

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Development of Loader Equipped with 4Wd and 4WS (II) (4WS System and Construction of Loader) (4WD 및 4WS이 가능한 로더 개발 (II) (4륜 조향장치 및 로더 구성))

  • 조현덕
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.1
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    • pp.150-157
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    • 1999
  • In this study, the loader was completed that has 4-wheel gear driven drivetrain of study (Ⅰ), the 4-wheel steering with power wheel type, all-wheel traction system, and joy-stick type lever for hydraulic control valve. From driving test of the developed 4WD and 4WS type loader, we obtained that the minimum circling radius and the necessary width in circling motion reduced about 40% and 33% compared with 2WS type loader. Also, all-wheel traction system could keep the tires glued to the ground with greater stability, the power steering allowed a smoother operation, and the joy-stick type lever offered easily to control. Thus, the developed loader having these functions was very fit in a small cattle shed or rugged ground.

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Quantitative Comparisons of the Characteristics of various Rapid Prototypes and RP machines (여러 가지 방식의 쾌속조형물 특성 및 장비 성능의 정량적 비교)

  • Kim, Gi-Dae
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.1237-1242
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    • 2007
  • For the various RP processes and machines, quantitative comparisons were carried out, which include the variations of roughness according to inclined angle of surface, tensile strength and heat-resistance, shape accuracy affected by curl distortion, manufacturability of submilli-scale structure, and manufacturing speed. It was observed that steeper surface results in smoother roughness except Eden500V of Objet. Specimen made by LOM process showed the best heat-resistance, but that of SL process had heat-resistance only up to $60^{\circ}C$. Generally, tensile strength in the building direction was shown to be smaller than in the scanning direction, but SL process showed the opposite results. RM6000II of CMET was superior in the manufacturing small-scale structure below 0.2mm, and Z510 of Zcorp. and ViperPRO of 3D systems were great in manufacturing speed.

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