• Journal of Korea Foundry Society
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• v.15 no.4
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• pp.408-415
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• 1995

Polycrystalline Al-Cu ribbons were produced by planar flow casting(PFC). Solidification behavior and microstructual changes of the ribbons have been investigated as a function of ribbon thickness and processing parameters. The solidification front velocity, V varies within the ribbon, decreasing with increasing the distance, S from the wheel-contact surface, as $V=17.6S^{-1}$. In Al-4.5wt%Cu alloy, rapid decrease in solidification velocity toward the free surface causes a change in solidification morphology from planar to cellular, and finally, to dendritic. The length and inclination of columnar grains solidified with planar front were related to the wheel velocity. The transition from particulate degenerate eutectic structure to regular lamellar eutectic structure was observed to be caused by a difference of the relative growth velocites of ${\alpha}-Al$ and ${\theta}$ during solidification in the Al-Cu eutectic alloy.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.68-68
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• 2010

To reduce PV manufacturing costs, the thickness of solar cell is getting thinner. Bow is shown after cooling down the temperature of solder cell. It happens because of different thermal expansion coefficients of different metals. Bowed cell can make micro crack while module processing and it can drop off efficiency of PV module. As thinner solar cell is produced, the thickness of ribbon should be concerned to prevent extra bow. In this paper we investigate the contrast of deflection when we solder different thickness of ribbons on same solar cell. This approach would help to find out the optical thickness of ribbon for particular thickness of solar cell later on.

• RED RIBBON
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• s.63
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• pp.10-13
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• 2005

증가하는 HIV/AIDS 감염과 그로 인한 파괴적 결과는 세계적 관심사가 되었고, 발병률이 높은 지역에서 AIDS는 보건의료 문제를 넘어서 국민총생산을 감소시키는 사회경제적 문제가 되고 있다. 한국은 상대적으로 HIV감염 AIDS 발병률이 낮은 나라지만 당초 예상과는 달리 그 발병률이 둔화되고 있지 않으며, 1999년 이후 최근에는 감염자의 수가 급격히 증가하는 추세에 있다. 세계 다른 나라들이나 아시아의 주변국의 사정을 보면 우리나라도 결코 안전한 권역에 계속 머물러 있으리라는 장담을 하기가 어렵다. 특히 근년에 경제적 생산력이 왕성한 $20\~30$대 남성에서 HIV/ADIS 증가하고 있어, HIV/AIDS감염의 사회적 비용, 그 중에 특히 경제적 영향에 대한 관심이 커지고 있는 상황이다. 따라서 우리나라에서 발생하는 HIV/AIDS의 경제적 비용을 추산함으로써 증가하는 HIV/AIDS감염의 경제적 의미를 찾을 필요가 있다고 판단된다. 경제적 비용의 추산에 앞서 우선 우리나라 HIV/AIDS 감염자 수를 추계하여 보면 다음과 같다.

• RED RIBBON
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• s.61
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• pp.10-11
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• 2004

전세계적으로 2003년 말 HIV감염자는 3,780만 명에 달하며 그중 여성이 차지하는 비율은$45\%$로 1,700만 정도 되며 15세 미만의 감염자가 210만 명을 차지한다. 우리나라의 경우 2004년 6월까지 총 2,842명의 감염자가 있으며 그중 여성 감염자는 288명으로 $10\%$를 차지,$70\%$이상이 20세에서 39세 사이의 가임기 연령이다. 이성간의 성접촉이 주된 감염경로인 아프리카와 아시아 일부 국가를 보면 남녀의 성비가 1:1에 가까운 데 비하여 우리나라 감염자의 성별 분포는 그렇지 않은 게 특징이다. 하지만 감염경로를 고려해 본다면 우리나라에서도 여성 감염자가 앞으로 더욱 증가할 수 있으며, 이는 향후 수직감염에 의한 신생아 감염도 늘 수 있어 무엇보다도 이에 따른 올바른 교육과 적절한 치료가 중요하다고 할 수 있겠다.

• Transactions of Materials Processing
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• v.8 no.6
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• pp.626-633
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• 1999

$Al_{85}Ni_{10}Y_5$ (at. %) amorphous alloy ribbons have been produced by rapidly solidification process and consolidated by the conventional powder metallurgy method. The grains with ∼90 nm were obtained in the Al85Ni10Y5 alloy extrudates by hot-pressing followed by hot-extusion. To investigate the effect of heat treatment on microstructural change of the extrudates, heat treatment was carried out from 200℃ to 400℃ at the step of 50℃. In addition, mechanical properties of the extrudates were analysed from torsion test at the temperature range or 400∼500℃ under a strain rates of 0.2, 0.5, and 1.0/sec. The extrudates showed a flow stress of ∼190 MPa and low elongation of ∼150% at 400℃, contributing to the enhancement of ductility and hardness for extrudates. Also, grain boundary sliding was occurred in the $Al_{85}Ni_{10}Y_5$ alloy during hot deformation.

• Journal of Powder Materials
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• v.2 no.3
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• pp.208-215
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• 1995

The aging effects on the characteristics of the melt spun Cu based shape memory alloys have been investigated by the microhardness test, X-ray diffraction, differential scanning calorimetry, scanning electron microscopy and transmission electron microscopy. After aged for specific times, hardness of the ribbons began to increase and shape memory capacity diminished. At the initial stage of aging the austenitic transformation temperatures increased gradually, but at last became nearly constant: That is, the aging deteriorated the thermal stability. The increase in hardness was due to the formation of the $\gamma_2$ precipitates. The loss in the shape memory capacity was due to the decrement of solute atoms in the matrix by the formation of the $\gamma_2$ precipitates. In this study, it was confirmed that Mn is an effective element for Improving the thermal stability.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.104-105
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• 2014

마이크로 패턴된 Au 전극사이에 얼라인된 Tellurium (Te) 나노리본들이 의도한 모양과 배열방식을 가지고 리쏘그래피 패턴 전해증착 (Lithographically patterned nanowier electrodepositon, LPNE) 방법에 의해 4인치 Si wafer 배치로 합성되었다. 합성된 Te 나노리본은 수 센티미터의 길이를 가지고, 그 두께와 폭 역시 작업 전극으로 사용되는 Si wafer위에 증착된 Ni의 두께와 전해증착 시간에 의해 쉽게 제어될 수 있다. $3{\mu}m$의 간격을 갖는 Au 전극 사이에 얼라인된 두께 ~100nm의 Te 나노리본들은 전해증착에 의해 그 폭이 제어되었고, 각각의 다른 폭을 갖는 증착된 하나의 Te 나노리본들의 IV 및 FET 측정을 통하여 나노리본 폭의 변화에 따른 전기적 특성 (비저항, FET 이동도 및 FET 캐리어 농도)이 평가되었다.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.5
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• pp.496-500
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• 1991

The effects of annealing with and without magnetic field on magnetic properties of amorphous Fe-B-Si cores have been investigated as a function of toroidal stress. By decreasing the toroidal stress, the magnetic properties of the amorphous ribbon have beenimproved. Near 180 domain walls exist in the thermally annealed toroidal cores, but the domain walls exist in the thermally annealed toroidal cores, but the domain walls are not parallel to the longitudinal direction of the ribbon. In the specimen annealed with a magnetic field strength of 10 Oe in the longitudinal ribbon length axis, the domains are nearly parallel to the longitudinal direction due to the field induced uniaxial anisotropy resulting in further increase in the remanent magnetization and decrease in the coercive force and loss.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04a
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• pp.11-13
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• 2002

The performance of DC current sensor based on giant magnetoimpedance (GMI) effect in amorphous ribbon has been tested. The ribbon after field annealing shows the maximum GMI ratio of 30 % at 100 kHz measuring frequency. In the sensor element of sample wound the circular form, GMI ratio and sensitivity are decreased due to internal stress. The sensor voltage output increases with applied DC current up to 1 A with a good linearity, of which direction can be known due to asymmetric characteristics.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1345-1347
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• 1994

High frequency Magnetic Properties of amorphous $Fe_{78}B_{13}Si_9$ ribbon were studied. Squareness ( Br/Bs ) and coercive force ( Hc ) of the specimen field annealed at $380^{\circ}C$ for 2 hrs are changed with the tension and the measuring frequency. So, we could optimise the tension having good magnetic properties at a certain frequency.