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  • Title/Summary/Keyword: 수적층

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High Frequency Magnetic Characteristics of Co90Fe10 Thin Films and Co90Fe10/SiO2 Multilayers (Co90Fe10 박막 및 Co90Fe10/SiO2 다층박막의 고주파 자기특성)

  • 윤의중;진현준;박노경;문대철;김좌연
    • Journal of the Korean Magnetics Society
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    • v.8 no.5
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    • pp.300-307
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    • 1998
  • The Co90Fe10 single layer films were deposited on various substrates (glass, Si, polymide) using high vacuum RF magnetron sputtering system and nominall 1000 \AA thick Co90Fe10 alloy films had a good high frequency characteristic. MS and Han values obtained from the B-H characteristic of the 10×[100nmCo90Fe10/100nmSiO2] multilayers agreed well with those obtained by calculation. Complex relative permeability $(={\{\mu}_r={\mu}_r',-j{\mu}μ_r")$ at frequency f was measured from the transmission characteristics (S11,S21parameters) of the microstrip line which has a stacked structure consisting of sample magnetic films and a conductor and is connected to a network analyzer. The μrf characteristic was abtained from the megnetic absorption, which was analyzed from the S-parameter characteristics of the microstrip line. The μrf characteristic was also calculated from the μr"f-f characteristic using the Kramers-Kronig relation. The measurement results were confirmed to agree well with those obtained by calculations.culations.

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Mineralogical Characteristics of Tosudites from the Sungsan and Bubsoo Mines, Korea (성산광산과 법수광산에서 산출되는 토수다이트의 광물학적 특성)

  • Cho, Hyen-Goo;Kim, Won-Sa
    • Journal of the Mineralogical Society of Korea
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    • v.6 no.1
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    • pp.17-26
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    • 1993
  • Mineralogical characteristics of tosudite from the Sungsan and Bubson mines were studied and correlated using X-ray diffraction analysis, chemical analysis and electron microscopy. Tosudite occurs as an alteration product of Cretaceous volcanoclastic rocks in both mines. It is associated with microcrystalline quartz, dickite, illite/smectite or mica/smectite mixed-layer mineral. It forms cryptocrystalline aggregates with flaky habit. XRD analysis suggests that tosudite is an 1:1regularly interstratified dioctahedral smetite/dioctahedral chlorite. Bubsoo tosudite has more(00ℓ ) reflections and more periodice stacking sequence than Syngsan tosudite. Chemical analysis shows that tosudite is a Li-bearing aluminous 1:1 regularly interstrattified mineral composed of K-bedellite and donbassite. Cookeite component may be present in the chlorite layer. Bubsoo tosudite is more Al in tetrahedral site and Ca in interlayer, but less Al in octahedral site than Sugsan tosudite. Tosudite may be formed as the intermediate alteration products, forming after muscovite and before illite/smectite or mica/sCmectite, with the range from 100 C to 360 ~ 480 C. The hydrothermal solution forming tosudite may be acidic solution with high activities of Si and Al.

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The Application of Octa-Substituted Metallophthalocyanine Langmuir-Blodgett films for NO2 Measurement (수정진동자를 이용한 프탈로시아닌 LB박막의 NO2 감지 특성)

  • Kwon, H.J.;Lee, Y.J.;Chang, Y.K.;Kim, J.D.
    • Journal of Sensor Science and Technology
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    • v.7 no.4
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    • pp.254-262
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    • 1998
  • Multilayer Langmuir-Blodgett (LB) films coated on quartz crystal microbalance (QCM) of octa-substituted metallophhtalocyanines (MPc(OEH)8, M = Cu, Co, and Sn) and dihydrogen phthalocyanines (H2Pc(OEH)8) were used to quantify NO2 concentrations. They were exposed to various concentrations of NO2 in dry N2. Among the four phthalocyanines we tested, the metal-free H2Pc(OEH)8 was observed to be most sensitive to NO2. However, its LB film showed a partially irreversible behavior, that is part of the frequency change due to NO2 adsorption could not be recovered even after purging with pure N2 gas for an extended period. Examining the spectra of NMR and FTIR revealed fact that the irreversible portion of frequency change was due to ether groups in the linkage between side chains and the Pc unit. In order to remove the effect of such initial deactivation, on NO2 quantification experiment, a freshly fabricated LB film was treated at a high concentration of NO2 so that the ether sites were saturated. A pretreated LB film showed a reproducible performance for repeated uses. The CuPc(OEH)8 LB film showed a satisfactory sensing performance down to as low as 4 ppm. For the H2Pc(OEH)8 LB film, the lower detection limit was found to be 35ppb of NO2. In order to make the experimental condition more realistic, the carrier gas, dry nitrogen, was replaced by air. It was observed that the presence of oxygen, a weak electron acceptor, reduced the sensitivity and thus increased the sensing limit to hundreds of ppb. Results of experiments with moisture added showed that the interference of moisture was quite severe.

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Effects of Crosslinking Agent and Flame Retardant on the Dielectric Properties of Poly(phenylene ether)-based Polymer Substrate Material (폴리페닐렌에테르계 고분자 기판 소재의 유전특성에 대한 가교제 및 난연제의 영향)

  • Kim, Dong-Kook;Park, Seong-Dae;Yoo, Myong-Jae;Lee, Woo-Sung;Kang, Nam-Kee;Lim, Jin-Kyu;Kyoung, Jin-Bum
    • Polymer(Korea)
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    • v.33 no.1
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    • pp.39-44
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    • 2009
  • Polymer substrates were fabricated by using poly (phenylene ether) as a base resin, N,N'-m-phenylenedimaleimide (PDMI) as a crosslinking agent and decabromodiphenylethane as a flame retardant. The effects of crosslinking agent and flame retardant on physical properties such as dielectric property of the substrate were investigated. Thermal curing feature of PDMI with or without an initiator was analyzed by DSC, and then, PPE-PDMI test compositions were designed based on this result. Composite sheets were cast by film coater, laminated under vacuum and pressure, and then, the changes of dielectric constant, dielectric loss, peel strength, solder heat resistance and inflammability according to increasing amount of PDMI and flame retardant were evaluated, Dielectric constant and dielectric loss showed increasing trend with increasing amount of PDMI and flame retardant, but solder heat resistance and inflammability were improved. Peel strength was obtained higher than 1 kN/m when PDMI above 10 wt% was added, but slightly decreased as the amount of flame retardant increased. From the measured gel contents, the reaction mechanism of PPE-PDMI system was deduced to the formation of network structure by crosslinking PDMI with PPE rather than the formation of semi-IPN structure. In conclusion, the polymer composite substrate materials with dielectric constant of 2.522.65 and dielectric loss below 0.002 at 1 GHz were obtained and they will be proper for high frequency applications.

Effect of Stitching on Mechanical and Impact Properties of Glass Fiber Reinforced Composite (스티칭에 의한 유리섬유강화 복합재료의 물성 및 충격거동 변화)

  • Park, Jae-Yong;Kang, Tae-Jin;Yuk, Jong-Il
    • Korean Journal of Materials Research
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    • v.2 no.5
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    • pp.366-374
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    • 1992
  • Mechanical and impact properties of stitched S2 glass fiber reinforced polyester woven laminates composites have been studied. Laminates were stitched using Kevlar 49 thread with 1/2, 1, and 2 inch stitch spacing. Tensile and 3-point bending tests haute been performed to evaluate the mechanical properties of stitched and unstitched laminates. Impact tests at applied energy of 234.7J were performed to examine the impact behavior and toughness changes of the specimen. The same specimens were also tested repeatedly at low impact energy level of 110.2J for 3 times to evaluate damage tolerance properties. The tensile and 3-point bending test results showed that one inch spacing specimen had the highest tensile and flexural strength. It also showed the highest energy absorption capability and the best damage tolerance property at the repeated impact test. The half inch spacing specimen showed the lowest tensile strength and energy absorption property at the impact energy level of 234.7J, even though it had the highest frequency of stitching thread.

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Optimization of Crack-Free Polytypoidally Joined Dissimilar Ceramics of Functionally Graded Material (FGM) Using 3-Dimensional Modeling (폴리타이포이드 경사 방식으로 접합 된 이종 세라믹간의 적층 수의 최적화 및 잔류응력 해석에 대한 연구)

  • Ryu, Sae-Hee;Park, Jong-Ha;Lee, Sun-Yong;Lee, Jae-Sung;Lee, Jae-Chul;Ahn, Sung-Hoon;Kim, Dae-Keun;Chae, Jae-Hong;Riu, Do-Hyung
    • Korean Journal of Materials Research
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    • v.18 no.10
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    • pp.547-551
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    • 2008
  • Crack-free joining of Si3N4andAl2O3 using 15 layers has been achieved by a unique approach introducing Sialon polytypoids as a functionally graded materials (FGMs) bonding layer. In the past, hot press sintering of multilayered FGMs with 20 layers of thickness 500μm each has been fabricated successfully. In this study, the number of layers for FGM was reduced to 15 layers from 20 layers for optimization. For fabrication, model was hot pressed at 38 MPa while heating up to 1700, and it was cooled at 2/min to minimize residual stress during sintering. Initially, FGM with 15 layers had cracks near 90 wt.% 12H / 10 wt.% Al2O3 and 90 wt.% 12H/10 wt.% Si3N4 layers. To solve this problem, FEM (finite element method) program based on the maximum tensile stress theory was applied to design optimized FGM layers of crack free joint. The sample is 3-dimensional cylindrical shape where this has been transformed to 2-dimensional axisymmetric mode. Based on the simulation, crack-free FGM sample was obtained by designing axial, hoop and radial stresses less than tensile strength values across all the layers of FGM. Therefore, we were able to predict and prevent the damage by calculating its thermal stress using its elastic modulus and coefficient of thermal expansion. Such analyses are especially useful for FGM samples where the residual stresses are very difficult to measure experimentally.

The Changes of Solid, Nitrogen and Phosphorus Concentrations in Pig Slurry Stored at Various Depth of Slurry Storage Tank (돼지분뇨슬러리의 액비조내 저장깊이별 고형물 및 질소, 인의 함량분포에 관한 연구)

  • Jeong, Kwang-Hwa;Chung, Eui-Soo;Park, Chi-Ho;Kwag, Jung-Hoon;Choi, Dong-Yoon;Yoo, Yong-Hee
    • Journal of Animal Environmental Science
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    • v.12 no.3
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    • pp.161-168
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    • 2006
  • This paper describes the changes of characteristics of pig slurry according to storing depth. Most of the substances containing pollutants, such as were Management of manure and wastewater from animal confinement facilities is a critical factor for pollution control. With proper treatment processing method in both solid and liquid forms, it can be used as a fertilizer and soil conditioner. In Korea, liquid-manure handling system is very popular because its treatment and application is easy and labor saving. In the storage tank treatment, the period of fermentation process and solids-liquid separation averages six months and the supernatant liquid is being used as a fertilizer. In this study, the changes in chemical characteristics of pig slurry at varying depths of the storage tank were investigated. Results showed that the pH value of the fermented pig slurry was > 7, while the major pollutants such as BOD, SS, N and P were highest in the bottom of the tank. Therefore, the above findings proved that varying depths in the storage tank can influence the concentration of pollutants of the fermented pig slurry.

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Thickness Effect of SiOx Layer Inserted between Anti-Reflection Coating and p-n Junction on Potential-Induced Degradation (PID) of PERC Solar Cells (PERC 태양전지에서 반사방지막과 p-n 접합 사이에 삽입된 SiOx 층의 두께가 Potential-Induced Degradation (PID) 저감에 미치는 영향)

  • Jung, Dongwook;Oh, Kyoung-suk;Jang, Eunjin;Chan, Sung-il;Ryu, Sangwoo
    • Journal of the Microelectronics and Packaging Society
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    • v.26 no.3
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    • pp.75-80
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    • 2019
  • Silicon solar cells have been widely used as a most promising renewable energy source due to eco-friendliness and high efficiency. As modules of silicon solar cells are connected in series for a practical electricity generation, a large voltage of 500-1,500 V is applied to the modules inevitably. Potential-induced degradation (PID), a deterioration of the efficiency and maximum power output by the continuously applied high voltage between the module frames and solar cells, has been regarded as the major cause that reduces the lifetime of silicon solar cells. In particular, the migration of the Na+ ions from the front glass into Si through the anti-reflection coating and the accumulation of Na+ ions at stacking faults inside Si have been reported as the reason of PID. In this research, the thickness effect of SiOx layer that can block the migration of Na+ ions on the reduction of PID is investigated as it is incorporated between anti-reflection coating and p-n junction in p-type PERC solar cells. From the measurement of shunt resistance, efficiency, and maximum power output after the continuous application of 1,000 V for 96 hours, it is revealed that the thickness of SiOx layer should be larger than 7-8 nm to reduce PID effectively.

Distribution of Magnetic Field Depending on the Current in the μ-turn Coil to Capture Red Blood Cells (적혈구 포획용 미크론 크기 코일에 흐르는 전류의 크기에 따른 자기장 분포 특성)

  • Lee, Won-Hyung;Chung, Hyun-Jun;Kim, Nu-Ri;Park, Ji-Soo;Lee, Sang-Suk;Rhee, Jang-Roh
    • Journal of the Korean Magnetics Society
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    • v.25 no.5
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    • pp.162-168
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    • 2015
  • The μ-turn coil having a width of μm on the GMR-SV (giant magnetoresistance-spin valve) device based on the antiferromagnetic IrMn layer was fabricated by using the optical lithography process. In the case of GMR-SV film and GMR-SV device, the magnetoresistance ratios and the magnetic sensitivities are 4.4%, 2.0%/Oe and 1.6 %, 0.1%/Oe, respectively. In the y-z plane the distribution of magnetic field of GMR-SV device and 10μ-turns coil which put under the several magnetic bead(MB)s with a diameter of 1μm attached to RBC (red blood cell) was analyzed by the computer simulation using the finite element method. When the AC currents of 20 kHz from 0.1 mA to 10.0 mA flow to the 10 turns μ-coil, the magnetic field at the position of z=0μm at the center of coil was calculated from 30.1μT to 3060μT in proportion to the current. The magnetic field at the position of z=10μm was decreased to one-sixth of that of z=0μm. It was confirmed that the 10μ-turn coil having enough magnitude of magnetic field for the capture of RBC is possible to use as a biosensor for the detection of magnetic beads attached to RBC.

Marine Terraces and Quaternary Faults in the Homigot and the Guryongpo, SE Korea (호미곶과 구룡포지역 해안단구와 신기지구조운동)

  • Choi, Sung-Ja
    • The Journal of the Petrological Society of Korea
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    • v.25 no.3
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    • pp.231-240
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    • 2016
  • Three Quaternary faults have been revealed in marine terraces nearby the Homigot and the Gurongpo in the southeastern offshore of Korean Peninsula. The Hajung fault cuts the 4th marine terraces and the Guman fault the 2nd, respectively. The Hajung fault strikes N55 to 45W and dips 40 to 45NE with reverse-displacement of 180cm vertically. There are four sets of colluvial sediment strata that would be produced by faulting and indicate four times of fault movements during MIS 7 and MIS 5c. The Guman fault site consists of three sets of reverse faults that strike N80E to N70W and dip 2535SE to 30SW with vertical displacement of 9~18 cm. The Guman faulting occurred during 80 ka (MIS 5a) to 71 ka (MIS 4) but it extends only to the lowest bed, the pebble sand bed, lay just on the unconformity, and not to the upper. Considering the attitude of the faults, we inferred that the Hajung fault was activated under the ENE-WSW compression during MIS 7 to MIS 5c and the Guman under N-S trending compression during MIS 5a. Using the OSL age dating results, we reconfirmed that the 2nd terrace is correlated to MIS 5a and the 4th terraces to MIS 7.