• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2004년도 추계학술대회 논문집
• /
• pp.1025-1028
• /
• 2004

In this paper, we studied low cycle fatigue behavior of laser welded sheet metal that used automobile body panel. Specimens were manufactured as weld condition and sheet metal using automobile manufacturing company at present. For to know mechanical properties, micro Vicker's hardness test was performed of specimens. But, we can't confirm mechanical properties of weld bead and heat affected zone because laser weld makes very narrow weld bead and heat affected zone than other welding method. Therefore, we performed low cycle fatigue test with similar weldment, dissimilar weldment, similar thickness and dissimilar weldment, and dissimilar thickness and dissimilar weldment for fatigue properties of thickness and welding direction. As well, we analysis stress distribution of base metal, weld bead, and heat affected zone according to strain load using finite element method.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
• /
• pp.1015-1018
• /
• 2004

We investigate the influence of the New Electron Injection Layers (EIL) on the performance of the Alkali Metal Complex vapor-deposited Organic Light Emitting Diodes(OLED). Two different Alkali Metal Complex were used; Lithium Quinolate (Liq), and Sodium Quinolate (Naq). In all cases, $Alq_3$ was the Electron Transporting Layer (ETL). We measure and compare the current density-voltage (J-V) and luminance-voltage (L-V) characteristics. We concluded that the turn-on voltage, and luminance efficiency are controlled by the type of EIL material used. We show the longer life-time OLED with Alkali Metal Complex EIL than OLED with LiF EIL. And we show the Optimized Alkali Metal Complex thickness is 3nm. Existent LiF to because is inorganic material, there is trouble to do epitaxy into thin layers but regulates the thickness in case of Alkali Metal Complex matter characteristic that is easy be. Alkali Metal Complex also appeared by sensitive thing in thickness than LiF If utilize this material, It is thought much advantages may be at common use of OLED.

• ETRI Journal
• /
• 제45권6호
• /
• pp.1056-1064
• /
• 2023

The optical properties of the materials composing organic light-emitting diodes (OLEDs) are considered when designing the optical structure of OLEDs. Optical design is related to the optical properties, such as the efficiency, emission spectra, and color coordinates of OLED devices because of the microcavity effect in top-emitting OLEDs. In this study, the properties of top-emitting blue OLEDs were optimized by adjusting the thicknesses of the thin metal layer and capping layer (CPL). Deep blue emission was achieved in an OLED structure with a second cavity length, even when the transmittance of the thin metal layer was high. The thin metal film thickness ranges applicable to OLEDs with a second microcavity structure are wide. Instead, the thickness of the thin metal layer determines the optimized thickness of the CPL for high efficiency. A thinner metal layer means that higher efficiency can be obtained in OLED devices with a second microcavity structure. In addition, OLEDs with a thinner metal layer showed less color change as a function of the viewing angle.

• Current Photovoltaic Research
• /
• 제9권4호
• /
• pp.128-132
• /
• 2021

Advances in screen printing technology have been led to development of high efficiency silicon solar cells. As a post PERx structure, an n-type wafer-based rear side TOPCon structure has been actively researched for further open-circuit voltage (Voc) improvement. In the case of the metal contact of the TOPCon structure, the poly-Si thickness is very important because the passivation of the substrate will be degraded when the metal paste penetrates until substrate. However, the thin poly-Si layer has advantages in terms of current density due to reduction of parasitic absorption. Therefore, poly-Si thickness and firing temperature must be considered to optimize the metal contact of the TOPCon structure. In this paper, we varied poly-Si thickness and firing peak temperature to evaluate metal induced recombination (Jom) and contact resistivity. Jom was evaluated by using PL imaging technique which does not require both side metal contact. As a results, we realized that the SiN_x deposition conditions can affect the metal contact of the TOPCon structure.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
• /
• pp.86-87
• /
• 2005

Aluminum(Al) sputtering is best known method to form Al film for the Si wafer in the process of 180nm and above. In the Al metal line process, one of the frequently founded and well-known defect was metal depression. In this paper, several experiments were performed such as temperature, Ar gas flow rate, thickness change in other to reduce the metal depression and find the origination of metal depression. Through experiments, it is found that metal depression was significantly related to the temperature. And the Ar gas flow rate did not influence to the creation of depression. The off status ESC also showed stable metal film without depression by same mechanism of temperature decrease. Also, thickness is strongly influence to the metal depression.

• 소성∙가공
• /
• 제19권3호
• /
• pp.179-184
• /
• 2010

The present study is focused on the deep drawability and product qualities of ultra thin beryllium copper sheet metal. The goal of this research is to investigate the limit drawing ratio in deep drawing of ultra thin beryllium copper metal. For the experiment, beryllium copper(C1720, $50{\mu}m$ in thickness) is used. Tensile test are also carried out to find out the material properties. Deep drawing experiments are carried out in Universal Testing Machine(UTM) to obtain limit drawing ratio. Deep drawing tests are carried out for various specimen sizes. Teflon film is used as a lubricant and constant blank holding force is imposed. Sheet thickness and surface hardness are measured along radial direction after deep drawing. Thickness is measured using optical microscope. For beryllium copper(C1720), the maximum LDR of 2.4 is obtained when the die shoulder radius is 20 or 30 times of sheet thickness.

• Journal of Welding and Joining
• /
• 제1권2호
• /
• pp.53-60
• /
• 1983

COD test based on fracture mechanics concept was used in this study to evaluate the fracture toughness quantitatively. Effects of specimen sizes on critical COD value for ABS EH 36 steel and its submerged arc weldments, and the variation of critical COD value depending on metallurgical/mechanical heterogeneities caused by weld thermal cycles were investigated. Experiment was performed by using specimens made from base metal and submerged arc weldments according to BS 5762. Obtained results are summarized as follows; 1) Critical COD value for base metal decreases with increasing thickness of specimen. On hand, as the reduction ratio of critical COD decreases with increasing specimen thickness, critical COD value becomes constant above a thickness of specimen. 2) Critical COD value for weldment decreases with increasing thickness of specimen and was also affected by metallurgical states of base metal. 3) Size effects for weldment was greater at the hardened region. 4) Critical COD value was affected by microstructural change due to weld thermal cycles in weldments; that is, accicular ferrite formation is favorable for increasing of COD value.

• Current Optics and Photonics
• /
• 제2권4호
• /
• pp.378-382
• /
• 2018

In most previous investigations of plasmonic and metamaterial applications, the metallic film has been regarded as a perfect electrical conductor. Here we demonstrate the resonance characteristics of THz metamaterials fabricated from metal film that has a finite dielectric constant, using finite-difference time-domain simulations. We found strong redshift and spectral broadening of the resonance as we decrease the metal's plasma frequency in the Drude free-electron model. The frequency shift can be attributed to the effective thinning of the metal film, originating from the increase in penetration depth as the plasma frequency decreases. On the contrary, only peak broadening occurs with an increase in the scattering rate. The metal-thickness dependence confirms that the redshift and spectral broadening occur when the effective metal thickness drops below the skin-depth limit. The electromagnetic field distribution illustrates the reduced field enhancement and reduced funneling effects near the gap area in the case of low plasma frequency, which is associated with reduced charge density in the metal film.

• 한국위험물학회지
• /
• 제6권2호
• /
• pp.55-61
• /
• 2018

In this study, the molten metal protective performance of various molten metal protective clothing materials such as herringbone twill laminated aluminium foils, oxydized-polyacrylonitrile laminated with aluminium deposited polyethylene terephthalate films, twill fabric laminated with aluminium deposited polyethylene terephthalate films and nonwoven laminated with aluminum deposited polyethylene terephthalate films, were evaluated according to modified EN ISO 9185. The results showed that the molten metal protective performance of tested samples improved with the increase in fabric structure density, weight and thickness. In addition the effect of the thickness of aluminum foil on the molten metal protective performance is not significant. It was found the fabric is more important in the molten metal splash protective clothing.

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2005년도 Proceedings of The 6th korea-china joint workshop on nuclear waste management
• /
• pp.39-50
• /
• 2005

Electrolytic reduction of uranium oxide to uranium metal was studied in a $LiCl-Li_{2}O$ molten salt system. The reduction mechanism of the uranium oxide to a uranium metal has been studied by means of a cyclic voltammetry. Effects of the layer thickness of the uranium oxide and the thickness of the MgO on the overpotential of the cathode and the anode were investigated by means of a chronopotentiometry. From the cyclic voltamograms, the decomposition potentials of the metal oxides are the determining factors for the mechanism of the reduction of the uranium oxide in a $LiCl-3\;wt{\%} Li_{2}O$ molten salt and the two mechanisms of the electrolytic reduction were considered with regards to the applied cathode potential. In the chronopotentiograms, the exchange current and the transfer coefficient based on the Tafel behavior were obtained with regard to the layer thickness of the uranium oxide which is loaded into the porous MgO membrane and the thickness of the porous MgO membrane. The maximum allowable currents for the changes of the layer thickness of the uranium oxide and the thickness of the MgO membrane were also obtained from the limiting potential which is the decomposition potential of LiCl.