• Membrane Journal
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• v.22 no.1
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• pp.1-7
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• 2012

We make a studyof the hydrogen permeability and chemical stability of $Nb_{56}Ti_{23}Ni_{21}$ metal alloy membrane. For this purpose, we produced the $Nb_{56}Ti_{23}Ni_{21}$ membrane which has 10 mm diameter and 0.5 mm thick, and experiment the hydrogen transport properties under two kinds of feed gas ($H_2$ 100%; $H_2$ 60% + $CO_2$ 40%) at $450^{\circ}C$C with variation of absolute pressure.The maximum hydrogen permeation flux was $5.58mL/min/cm^2$ in the absolute pressure 3 bar under pure hydrogen. And each case of feed gases about gas composition, the permeation fluxes were satisfied with Sievert's law, and the hydrogen permeation flux decreased with decrease of hydrogen partial pressure irrespective of temperature and pressure. After permeation test, we experiment the stability and durability of $Nb_{56}Ti_{23}Ni_{21}$ alloy membrane for carbon dioxide by XRD analysis.

• Computers and Concrete
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• v.21 no.3
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• pp.311-319
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• 2018

This study used a volumetric method for design. The control group used waste Liquid Crystal Displayplay (LCD) glass powder to replace cement (0%, 10%, 20%, 30%), and the PZT group used Pd-Zr-Ti piezoelectric (PZT) powder to replace 5% of the fine aggregate to make cement mortar. The engineering and the mechanical and electricity properties were tested; flow, compressive strength, ultrasonic pulse velocity (UPV), water absorption and resistivity (SSD and OD electricity at 50 V and 100 V) were determined; and the correlations were determined by linear regression. The compressive strength of the control group (29.5-31.8 MPa) was higher than that of the PZT group (25.1-29 MPa) by 2.8-4.4 MPa at the curing age of 28 days. A 20% waste LCD glass powder replacement (31.8 MPa) can fill up finer pores and accelerate hydration. The control group had a higher 50 V-SSD resistivity ($1870-3244{\Omega}.cm$), and the PZT group had a lower resistivity ($1419-3013{\Omega}.cm$), meaning that the resistivity increases with the replacement of waste LCD glass powder. This is because the waste LCD glass powder contains 62% $SiO_2$, which is a low dielectric material that is an insulator. Therefore, the resistivity increases with the $SiO_2$ content.

• Journal of Sensor Science and Technology
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• v.13 no.5
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• pp.399-404
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• 2004

We report on the technology of formation of sandwich structures based on fullerite films and on experimental results in research of optical and conductivity properties of these sandwich samples. Single crystals of sapphire (100) or silicon were used as substrates. The sandwich specimens were based on the structure M/$C_{60}$/M (M=Cr, Pd, Ag, Al, Cu). The thickness of the fullerite films was about $0.2{\sim}1.0{\mu}m$. The area of the $C_{60}$ film under the top contact was about $1cm^{2}$. The specimens have been investigated by infrared spectroscopy, spectra-photometry, ellipsometry and X-ray diffraction analysis. Measurements of the current/voltage characteristics and research on the temperature dependence of conductivity were performed as well. It was shown that metals such as Cr, Pd, Ag, Al, and Cu penetrate easily into the fullerite films. It appears that these specimens have a large conductivity. For silver/$C_{60}$ and other sandwich structures the conductivities show a semiconductor-like behaviour.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.509-510
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• 2008

본 논문은 $0.18{\mu}m$ CMOS 공정을 사용하여 2.5Gb/s CMOS CDR을 설계하였다. CML type의 논리게이트를 이용하여 보다 높은 주파수의 대역의 데이터를 복원하기 위한 위상비교기(PD)와 PD의 up과 down신호를 지연없이 루프필터(LF)에 공급하기 위한 전하점프(CP) 그리고 외부 스위치를 통해 VCO이득을 조절할 수 있는 링 타입의 VCO로 구성되었다. 또한 VCO의 부담을 줄이기 위하여 half-rate 클럭 테크닉을 사용하였다. Cadence tool을 사용하여 모의실험 및 layout을 하였다. VCO이득은 100MHz/V이고, 클릭 jitter는 rising일 때 27ps, falling일 때 32ps로 우수한 결과를 얻을 수 있었다. 테스트칩 제작은 매그나침 $0.18{\um}$ CMOS 공정을 이용하였다. 칩 사이즈는 PAD를 포함하여 $850um{\times}750um$이다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04c
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• pp.27-31
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• 2008

In this study, The new type of loop antenna which detects the partial discharge was designed based on microstrip line technology. In diagnosis of power cable, partial discharge signal generally occurred at the frequency range lower than 100MHz because high frequency PD signals could be lost along the propagation path in the cable. The new type of loop antenna sensor has been studied by using Simulation software named CST microwave studio version 5.0. In partial discharge measuring experiments, commercial HFCT sensor was used as a reference sensor. Several experiments were made over HFCT sensor and loop antenna sensor in detection partial discharge on MV XLPE cable of 22.9kV. In this study, we have shown our loop antenna sensor can apply as a commercial HFCT sensor.

• Journal of Hydrogen and New Energy
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• v.19 no.1
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• pp.35-40
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• 2008

Ni-based amorphous alloy ribbon was prepared by a single-roller melt-spinning technique. Palladium coating was found to enhance significantly the absorption/desorption behavior of hydrogen in amorphous alloy. The hydrogen permeability of a Pd-coated $(Ni_{60}Nb_{40}){_{100-X}}$TaX(x=5, 10) amorphous alloy was examined in the temperature range of $623{\sim}773K$, comparable with those of $Pd_{60}-Cu_{40}$ alloys. The permeated hydrogen flux was increased with increasing the temperature and the difference of hydrogen pressure between the feed side and permeates side of the membrane. The Ni-based amorphous alloys were characterized by X-ray diffractometry(XRD) and differential scanning calorimetry(DSC). The morphology of surface and roughness was observed by using scanning electron microscopy(SEM) and atomic force microscopy(AFM).

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.10
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• pp.840-846
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• 1991

In case of the rapid thermal process by halogen lamps, an optical pyrometer is generally used to measure the temperature. It is, however, necessary to measure the temperature by the thermocouple when the process temperature is lower than 700$^{\circ}C$ and the correction of the temperature is required. Contact by the PdAg paste is commonly used out but in this case it is impossible to see the effect of surface states of the substrate, which is critical in the rapid thermal process. In this study, real temperature ramping speed of silicon substrates coveredwith various thin films such as SiO$_2$2, Si$_{3}N_{4}$, dopants, and conductive layers (Ti or Co) was investigated by a mechanical contact of the thermocouple. And the results were compared with the case in which the contact was made by the PdAg paste. Effect of process ambient was also studied. It was found that depending on the surface state, overshoot more than 100$^{\circ}C$ could occur. It was also found that in case of the substrate covered with conductive layers, mechanical contact might render the correct temperature.

• Journal of Electrical Engineering and Technology
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• v.3 no.4
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• pp.559-565
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• 2008

This study designed a new type of loop antenna that is able to detect partial discharges based on microstrip line technology. In the diagnosis of power cables, partial discharge signals are generally produced at a frequency range less than 100MHz because high frequency PD signals are lost along a propagation path in such cables. The new type of loop antenna sensor has been studied using simulation software known as CST microwave studio version 5.0. In partial discharge measurement experiments, a commercial HFCT sensor was used as a reference sensor. Several experiments were made over HFCT and loop antenna sensors for detecting partial discharges on 22.9kV MV XLPE cable. In this study, we showed the loop antenna designed in this study that can be applied as a commercial HFCT sensor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.464-464
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• 2007

환경오염으로 인한 각종 질병 및 증후군 등의 발생으로 가정용 산업용에서 환경관련 기술들이 다양한 분야로 확대되고 있다. 본 연구에서는 양이온 및 음이온 양쪽이온을 최대한 발생시키며, 오존 발생량은 억제하고 소비전력을 절감하고자 Ag-Pd 전극을 적용한 세라믹스 클러스터를 개발하였다. Ag-Pd 전극과 매칭되는 세라믹스 조성을 개발한 후 적층공정 기술을 이용하여 후막형 클러스터를 제조하였다. 전극 패턴모양, 전극간 방전간격 및 전극 보호층의 두께에 따른 음이온 발생량을 측정하여 최적화를 위한 실험을 진행하였으며, 음이온 발생량 100만개이상, 오존발생량 0.6ppb인 특성을 확인하였다.

• Applied Biological Chemistry
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• v.9
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• pp.111-118
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• 1968

A pot experiment with $P^{32}$ was carried out to investigate the soil phosphorus availability to four leguminous forage crops and three graminaceous, of black volcanic ash soil and red one. Soil phosphorus was extracted with 6 different extractants and also fractionated in Fe, Al and Ca phosphorus. The results were: 1) Soil phosphorus availability was in decreasing order of Italian rye grass${\gg}$ soybean> cassia> corn> weeping love grass${\gg}$ Korean lespedeza> Red clover and they might be grouped into three levels by A-value, over 1000, 200-500 and below 40 $p_{2}O_{5}\;kg/ha$. 2) The amount of various available phosphorus and phosoborus fraction in the black soil was higher than that in the red soil. No difference in phosphorus availabiliy to forage crops was shown between two soils. Therefore an extractant able to draw out similar amount of phosphorus from two soil will be suitable for determining the phosphorus availability index. 3) Two extractants, one extracting 20 ppm as maximum and the other extracting 100 ppm as minimum will be recommendable for determining the availability of phosphorus; the former for red clover and Lespedeza and the latter for others. Truog method may be good for the former but no appropriate method for the latter was found in the methods used. 4) T/R ratios of legumes were negatively correlated at 5% level with % phosphorus from fertilizer (% pdF). Legumes showed below 50 of % pdF over 5 of T/R ratio and over 80 of % pdF below 5 of T/R.