• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2006년도 춘계 학술대회 개요집
• /
• pp.68-70
• /
• 2006

For the aluminum material of the thick-thickness more than 100mm Penetration depth Electron beam welding is effectively applicable with a characteristic of high energy intensity. But Al 6061 alloy has high crack sensitivity due to minor alloys, which are silicon, magnesium, copper etc. With a sample block of 135mm thickness EBW test was performed in vertical position. As tensile strength has $210{\sim}220N/mm^2$ with weld area broken. Bend test shows low ductility with fracture of partly specimens. Chemical contents of alloys show no difference between weld and base metal. Defect in middle weld area figures out typical hot crack due to low melting materials. Micro structure of weld area has some difference compare to HAZ and base metal. As a result of EBW test for Al 6061 alloy, it shows that weld defect could be occurred even though establishing of optimum weld parameter condition.

• Journal of Magnetics
• /
• 제18권4호
• /
• pp.417-421
• /
• 2013

The dominant magnetization reversal behavior of electrodeposited CoPt samples with various thicknesses deposited at different current densities was the domain wall motion by means of wall pinning. The magnetic interaction mechanism was dipolar interaction for all samples. The dipolar interaction strength was significantly affected by the sample thickness rather than by the current density, while the magnetic properties were closely related to the current density.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
• /
• pp.761-766
• /
• 1998

GPR(Ground Penetrating Radar) designed with a digital-based signal processing technology utilizes to identify very easily the location, the thickness and the level of either an underground embedment or an underground structure. Prior to use of this GPR equipment on pavement of about 15cm thick, the equipment should foremost be calibrated on a known sample under known condition. The purpose of this study is to verify the applicability of the GPR equipment to a model pavement of about 15cm thick. As part of this effort, the general approach of this study is to verify the applicability of the GPR equipment by various thickness levels and its error ranges thru a statistical analysis.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2008년도 춘계학술대회 논문집
• /
• pp.277-280
• /
• 2008

Recently, a demand of nano/micro patterned polymer for display or biochip has been rising. Then many studies have been carried out. Nano/micro-embossing is a deformation process where the workpiece materials is heated to permit easier material flow and then forced over a planar patterned tool. In this work, the hot-emboss process is performed with different forming conditions; forming temperature, load, press hold time, to get the proper condition for linear pattern fabrication on plated-type polymers (PC). Replicated pattern depth increases in proportion to the forming temperature, load and time. Reduction of the workpiece thickness increases according to press hold time. In process of time, reduction ratio of workpiece thickness decreases because of surface area increment of the workpiece and pressure decline on it.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2009년도 창립 20주년기념 특별학술발표회
• /
• pp.339-340
• /
• 2009

• 한국재료학회지
• /
• 제21권8호
• /
• pp.456-460
• /
• 2011

Microelectromechanical systems (MEMS)-fabricated suspended devices were used to measure the in-plane electrical conductivity, Seebeck coefficient, and thermal conductivity of 304 nm and 516 nm thick InGaAlAs films with 0.3% ErAs nanoparticle inclusions by volume. The suspended device allows comprehensive thermoelectric property measurements from a single thin film or nanowire sample. Both thin film samples have identical material compositions and the sole difference is in the sample thickness. The measured Seebeck coefficient, electrical conductivity, and thermal conductivity were all larger in magnitude for the thicker sample. While the relative change in values was dependent on the temperature, the thermal conductivity demonstrated the largest decrease for the thinner sample in the measurement temperature range of 325 K to 425 K. This could be a result of the increased phonon scattering due to the surface defects and included ErAs nanoparticles. Similar to the results from other material systems, the combination of the measured data resulted in higher values of the thermoelectric figure of merit (ZT) for the thinner sample; this result supports the theory that the reduced dimensionality, such as in twodimensional thin films or one-dimensional nanowires, can enhance the thermoelectric figure of merit compared with bulk threedimensional materials. The results strengthen and provide a possible direction in locating and optimizing thermoelectric materials for energy applications.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
• /
• pp.528-529
• /
• 2008

A new concept based on sample current measurements for detecting of via-hole defects on wafer has been performed by low energy electron beam microcolumn. The microcolumn has been operated at a low voltage of 290 eV with total emission current of 400 nA, and a sample current of 6 nA. The test sample was fabricated with SiO2 layer of 300 nm thickness on a piece of a silicon substrate. Preliminary results of both sample current method and secondary electron method show microcolumn and its control can be useful technology for detecting of via-hole defects on wafer.

• 대한기계학회논문집B
• /
• 제29권1호
• /
• pp.27-34
• /
• 2005

We analyze in detail axially symmetric theoretical study for the photothermal pulsed radiometry of a cylindrical model. The theoretical solutions describe the transient infrared radiation from the sample heated by short-duration pulsed heating. In the conventional transmission radiometry technique, the excitation source and the detector are on opposite sides of the sample, otherwise in the new single ended radiometry technique, the excitation source and the detector are on same sides of the sample. The analytical solution described for photothermal radiometry in this study would not need to cut or polish samples to measure the thermal diffusivity. Therefore the radial area and axial thickness of samples are not limited. The effects of excitation pulse duration and the area of heat source are discussed.

• 대한안전경영과학회지
• /
• 제2권1호
• /
• pp.89-97
• /
• 2000

This paper shows the study for development inprocess measuring magnetic sensor for tolerance control, First, we fabricated and annealed sample amorphous ribbons which were made of ($CO_{0.94}$$Fe_{0.06}$)$_{79}$$Si_{2}$$b_{19}$ having near zero magnetostrictive. It had 12［$\mu\textrm{m}$］ of thickness, 10［mm］ of length, and 2.5［mm］ of width. Then, we measured the magnetic characteristics such as frequency dependency over impedance variation rate and position change over impedance variation. As the results of the evaluation, we found that the sample ribbons had excellent sensor characteristics. Then, we made sensors by using the sample ribbons, As the results of the measurements, it proved that the ribbon could be used as excellent magnetic sensor for which it was possible to control inprocess measurement within the tolerance range(~$\mu\textrm{m}$ ).

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
• /
• pp.59-72
• /
• 1999

In this thesis, we measured the Barkhausen effect of CoFeSiB amorphous ribbon and then investigated its possibility to be used as a sensor material. We used a sample of composition $($Fe_{0.06}$$Co_{0.94}$)_${0.79}$$Si_{2.1}$$B_{18.9}$ with a thickness 12[pm1, width 2.5[rnml and length 5[cm], which was fabricated by a single roll method. In order to improve magnetic characteristics of the sample, we had carried on annealing in the magnetic field and in none magnetic field. And, experimented results to the magnetic characteristics show that the ribbon has large Barkhausen jump even in weak magnetic field below 0.5[0el. From the results, we confirmed that the sample can be used as an magnetic sensor material.