• Title/Summary/Keyword: base material

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A Study on Characteristics of Laser Cladding Layer of STS316L (STS316L 분말의 레이저 클래딩층 특성에 관한 연구)

  • Hong, SungMoo;Oh, JaeYong;Kim, DongSeob;Chang, SeungCheol;Shin, BoSung
    • Journal of the Microelectronics and Packaging Society
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    • v.24 no.3
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    • pp.53-56
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    • 2017
  • Laser cladding is a technique for forming beads by melt-sintering with a laser while directly feeding metal powder onto the base material through nozzles. This technique, which is applied in laser surface treatment technology, is useful for repairing broken or worn parts by allowing selective formation of the surface layer of the base metal material. In this paper, laser cladding process was performed on STS316L powder using high power continuous wave laser with IR wavelength and the cladding characteristics according to process conditions were experimentally analyzed.

Evaluation of Weldability and Formability of Tailor Welded Blank by Using Upset Weld (업셋 용접 테일러드 블랭크의 용접성 및 성형성 평가)

  • 민경복;장진호;강성수
    • Transactions of Materials Processing
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    • v.8 no.1
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    • pp.57-64
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    • 1999
  • The press formability analysis of welding parts was studied in the current work by the tailor welded blank. As the body panel is used in the press forming of welding parts by a weld method of the tailor welded blank, the following conditions are demanded: 1) The strength of welding parts must be the higher than base metals. 2) After the welding, severe welding deformatins must be avoided. 3) The press formability of welding parts is similar to that of many base metals. 4) The productibility of a welding has to be higher. There are many welding methods satisfying these conditions, but the purpose of this study is to inbestigate the upset weldability and formability of the material (SPCC). SPCC steel sheet showed good weldability and formability under some welding conditions. The experimental results were discussed by the evaluation of the results obtained from tensile tests, hardness tests, micro-structures and Erichsen cup test was a little lower than that of parent material.

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A Study of physical properties and application to new products from the Heavy Residual Feul oil as Raw Materials. (양산중질유의 대책에 따른 신제품 개발실용화에 관한 연구)

  • 김주항;강호근
    • Proceedings of the Korean Professional Engineer Association Conference
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    • 1984.12a
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    • pp.84-91
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    • 1984
  • Heavy Residual Fuel oils is a mixture of reduced crude from crude unit, bottom products from vacuum and/or catalytic cracking unit with distillate to meet the specification and generally used as Heavy Fuel Oil for large combustion engines, boilers, etc…. But this study was made to investigate Heavy Residual Fuel oils for using as industrial raw material and resulted the following possibilties as valuable raw material as well as Heavy Fuel Oil. 1) Production of straight asphalt through vacuum distillation unit. 2) Using straight asphalt from vacuum distillation unit for manufacturing of Blown Asphalts, Cut Back Asphalts, Emulsified Asphalts and Asphalt Compound, etc…. 3) Using waxy oil side streams for manufacturing of raw oil to be Lube Oil base stocks through solvent dewaxing. 4) Production of lube base oils from dewaxed raw oil through chemical treatments. 5) Manufacturing of paraffine wax from slack wax to be produced as by product of dewaxing process.

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Current Gain Characteristics of AlGaAs/GaAs HBTs with different Temperatures (온도변화에 따른 AlGaAs/GaAs HBT의 전류이득 특성)

  • 김종규;안형근;한득영
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.840-843
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    • 2001
  • In this study, temperature dependency of current gain for AlGaAs/GaAs/GaAs HBT is analytically proposed over the temperature range between 300K and 600K. Energy bandgap, effective mass, intrinsic carrier concentration are considered as temperature dependent parameters. Collector current which is numerically calculated is then analytically expressed to enhance the speed of calculation for current gain. From the results, current gain decreases as the temperature increases. These results will be used to expect the unity current gain frequency f$_{T}$ in conjunction with emitter-base and collector- base capacitances.s.

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Analysis of excess minority carrier and charge wish lifetimes in N-dirft region of NPT-IGBT (수명시간에 따른 NPT-IGBT의 N-drift 영역에서의 과잉소수 캐리어와 전하량 분석)

  • 류세환;이용국;안형근;한득영
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.844-847
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    • 2001
  • In this work, transient characteristics of the Non-Punch Through(NPT) Insulated Gate Bipolar Transistor(IGBT) has been studied. we has analyzed with lifetimes excess minority carrier injected into N-dirft, base region of IGBT's BJT part and accumulated charge of on-state which affected swiching characteristic. In this paper, excess minority carrier and charge distribution in active base region is expressed analytically. This analysis proposed optical trade-off between lifetimes and accumulated charge for decreasing switching losses because charge result in switching loss when device was tuned off.

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Theoretical Mechanism Studies on the Enantioselectivity of aza-MBH-type Reaction of Nitroalkene to N-tosylimine Catalyzed by Thiourea-tertiary Amine

  • Lu, Nan;Wang, Huatian;Wang, Yangping
    • Bulletin of the Korean Chemical Society
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    • v.34 no.12
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    • pp.3591-3596
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    • 2013
  • The enantioselective aza-Morita Baylis Hillman reaction of nitroalkene and N-tosylimine catalyzed by thiourea-tertiary amine has been investigated using density functional theory. Enantioselectivity is dominated by the cooperative effect of non-covalent and weak covalent interactions imposed by different units of catalyst. As Lewis base, the tertiary amine unit activates nitroalkene via weak covalent bond. The weak covalent interaction orients the reaction in a major path with smaller variations of this bond. The aromatic ring unit activates N-tosylimine via ${\pi}-{\pi}$ stacking. The non-covalent interaction selects the major path with smaller changes of the efficient packing areas. Thiourea unit donates more compact H-bonded network for species of the major path. The calculated ee value in xylene solution phase (97.6%) is much higher than that in N,N-Dimethylformamide (27.2%). Our conclusion is also supported by NBO analysis.

Characteristics of Street Lamp Controller with Earth Leakage Contactor (가로등 전용 누전 개폐기의 차단효과에 대한 고찰)

  • Lee, Seong-Jae;Shin, Jae-Sik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.06a
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    • pp.283-283
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    • 2010
  • Smart street light controller is a product with advance micro controller base for energy saving in conventional street lighting systems. Intelligent Street light controller are specially developed for automation and energy saving in conventional street light systems and lighting systems. It is so designed that it operates on sunrise & sun set timings according to longitude of particular location with facilitate to set month wise civil twilight timings to cope up with all seasons. Dimming (Power down) mode selection switch on/off at fixed times with relay or contactor. Night dimming, staggering and intelligent control reduces burn hours and increases the lifetime of lamps with about 30% and low annual operating cost type base are among the most inexpensive wireless technologies available. Low initial costs As PLC wireless, there is no need to establish cable connection.

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Effect of P-Base Region on the Transient Characteristics of 4H-SiC DMOSFETs (P형 우물 영역에 따른 4H-SiC DMOSFETs의 스위칭 특성 분석)

  • Kang, Min-Seok;Ahn, Jung-Jun;Sung, Bum-Sik;Jung, Ji-Hwan;Koo, Sang-Mo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.06a
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    • pp.352-352
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    • 2010
  • Silicon Carbide (SiC) power device possesses attractive features, such as high breakdown voltage, high-speed switching capability, and high temperature operation. In general, device design has a significant effect on the switching characteristics. In this paper, we report the effect of the P-base doping concentration ($N_{PBASE}$) on the transient characteristics of 4H-SiC DMOSFETs. By reducing $N_{PBASE}$, switching time also decreases, primarily due to the lowered channel resistance. It is found that improvement of switching speed in 4H-SiC DMOSFETs is essential to reduce the and channel resistance. Therefore, accurate modeling of the operating conditions are essential for the optimization of superior switching performance.

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Evaluation of Ct-parameter for Weld Interface Crack Considering Material Plastic Behavior (재료의 소성 거동을 고려한 용접 계면균열의 Ct 매개변수)

  • Yun, Gi-Bong;Lee, Jin-Sang
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.3 s.174
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    • pp.676-684
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    • 2000
  • In this study, behavior of $C_t$ which is a well-known fracture parameter characterizing creep crack growth rate, is investigated for weld interface cracks. Finite element analyses were per formed for a C(T) specimen under constant loading condition for elastic-plastic-creeping materials. In modeling C(T) geometry, an interface was employed along the crack plane which simulated the interface between weld and base metals. The $C_t$ versus time relations were obtained under various creep constant combinations and plastic constant combinations for weld and base metals, respectively. A unified $C_t$ versus time curve is obtained by normalizing $C_t$ with $C^*$ and t with $t_T$ for all the cases of material constant variations.

Study for Forming Limit of Pre-Coated Metal (프리코트 메탈의 성형한계에 관한 연구)

  • 왕신일
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1999.03b
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    • pp.159-162
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    • 1999
  • This study has been performed to investigate forming limit of PCM(Pre-Coated Metal) widely using appliances. Die set was made for deep drawing test and some PCMs were inrectangular deep drawing test in no-lubricant 20% clearance some die materials(STD11(TiCN) STD11(HrC60) STD11(TD) AMOCO and 6mm/sec punch speed. and Ericshen test was performed in regular conditions In this experiment forming limit forming characteistics superior die materials and fracture of PCMs been investigated. In results tested PCMs have lower forming limit than base material because lower elongation ultimate strength than base material And two-fracture types - occurring band and flaking - of PCMs have been investiqated.

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