• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.1883-1889
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• 2013

Although Fe-Si based alloy has lower figure of merit than Si-Ge alloy applied for space probe, its low cost related to abundant raw material, rather simple processing, high temperature resistance and reliability up to $800^{\circ}C$ made it one of the most promising middle temperature thermoelectric generation materials. The effect of particle size and additive on the thermoelectric properties of p-$FeSi_2$ prepared by a RF inductive furnace was investigated. The electrical conductivity increased slightly with decreasing particle size and hence better grain-to-grain connectivity due to the increase of density. The Seebeck coefficient exhibited the maximum value at about 600~800K and decreased slightly with increasing particle size. This must be due to the amount of residual metallic phase ${\varepsilon}$-FeSi. $Fe_2O_3$ and/or $Fe_3O_4$-doped specimens showed the higher electrical conductivity and the lower Seebeck coefficient due to increase of the metallic phase and Si-vacancy. On the other hand, $SiO_2$-doped specimen showed the higher electrical conductivity and the higher Seebeck coefficients.

• Journal of the Microelectronics and Packaging Society
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• v.7 no.3
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• pp.31-36
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• 2000

We developed embedded inductors in MCM-D substrate for RF applications. The increasing demand for high density packaging was the driving forces to the development of MCM-D technology. Most of these development efforts have been focused on high performance digital circuits. However, recently there is a great need fur mixed mode circuits with a combination of digital, analog and microwave devices. Mixed mode modules often have a large number of passive components that are connected to a small number of active devices. Integration of passive components into the high density MCM substrate becomes desirable to further reduce cost, size, and weight of electronic systems while improving their performance and reliability. The proposed MCM-D substrate was based on Cu/photosensitive BCB multilayer and Ti/Cu is used to form the interconnect layer. Seed metal was formed with 1000 $\AA$ Ti/3000 $\AA$ Cu by sputtering method and main metal was formed with 3 $\mu\textrm{m}$ Cu by electrical plating method. The multi-turn sprial inductors were designed in coplanar fashion. This paper describe the manufacturing process of integrated inductors in MCM-D substrate and the results of electrical performance test.

• Journal of Food Hygiene and Safety
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• v.34 no.4
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• pp.317-324
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• 2019

This study focuses on the role of nanotechnology in the field of food industries. Bioactive components with antimicrobial activity against food pathogens are encapsulated into nanoparticles (NPs) to improve and extend their efficiency in food preservation. However, these NPs should be biocompatible and nontoxic for humans. Advancement in this field has resulted in the development of NPs for food packaging in some industries. The most commonly used group of NPs in the food industry is metal oxide. As metal oxide NPs such as zinc oxide and titanium dioxide exhibit antimicrobial activity in food materials, the NPs can be used for food preservation with enhanced functional properties. The application and effects of nanotechnology in correlation with the nutritional and sensory properties of foods were briefly discussed with a few insights into safety regulations on nano-based food formulation and preservation.

• The monthly packaging world
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• s.230
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• pp.92-99
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• 2012

KOREA STAR AWARDS는 패키징 $\triangle$완제품 $\triangle$재료(플라스틱, 종이 판지, 금속, 유리, 목재, 복합소재) $\triangle$친환경 $\triangle$기계(설비) 및 관련 부품 $\triangle$ 인쇄(라벨링) $\triangle$부자재 $\triangle$생산 및 가공공정 $\triangle$패키징 디자인 등의 분야에서 신기술 개발과 지속가능성을 통해 패키징 산업 발전에 기여한 기업, 그리고 패키징 관련 정책연구, 기술개발, 패키징산업 육성에 기여한 개인에게 시상. 2012 KOREA STAR AWARDS는 코리아스타상(기업, 학생, 공로부문)으로 지식경제부장관상(상장4점, 표창2점), 한국생산기술연구원장상(상장 12점, 표창1점), 한국포장기술사회장상(상장 20점) 총 39점 시상. 코리아스타상 기업부문 지식경제부장관상은 '에이스기계 종이상자 자동접착기의 패스트 폴딩 장치', 'LG생활건강 이자녹스 SMART 진동시리즈', '삼성전자 냉장고 친환경 재사용 포장', '한국에이버리 친환경 수분리성 점착라벨' 4개 제품 수상. 코리아스타상 공로부문 지식경제부장관표창은 (주)경연전람 김영수 대표와 김수일포장개발연구소 김수일 소장 수여. 본 고에서는 "2011 미래패키징 신기술 정부포상" 수상작들의 패키징 동향 및 유공자들의 공적 내용을 살펴보도록 한다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.29.2-29.2
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• 2010

최근 박막형 LED 및 박막형 태양전지등의 기존 마이크로 소자들의 효율향상을 위한 개선으로 나노구조를 이용한 나노소자 제작이 관심을 받고 있다. 이는 가능성으로만 여겨져왔던 나노기술이 기존 박막형 소자에서 포화된 효율상향 접근방식의 한계에 따른 것으로 생각되며, 나아가 나노기술로 제작된 나노소자가 우리 생활을 채우게 될 날이 얼마남지 않은 것을 의미한다. 특히, 디스플레이 소자에서의 나노기술은 더욱 더 중요시 되고 있다. 그로 인해 투명성과 우수한 광전기적 특성을 지닌 산화물 반도체와 그 나노구조 대한 관심이 날로 높아지고 있으며, 그 가운데 산화아연계(ZnO, MgZnO등) 나노구조를 이용한 나노소자 제작이 많이 연구되고 있다. 산화아연은 c축으로 우선 배향성을 가지는 우르짜이트 구조로써, 나노선 성장이 다른 산화물에 비해 용이하고 그 물리적, 화학적 특성이 안정 우수하다. 이러한 산화아연 나노선 제작법 가운데, 유기금속화학기상증착법은 다른 성장법에 비해 결정학적 광학적 특성이 우수하고 성장속도가 빨라 고품질 나노선 성장에 용이한 장비로 각광받고 있다. 하지만 bottom-up 공정을 기반으로 한 나노소자제작에서 몇 가지 문제점을 가지고 있다. 1) 수직형 대면적 성장, 2) 나노선 밀도 조절의 어려움, 3) 기판과의 계면층에 자발적으로 생성되는 계면층의 제거, 4) 고온성장시 precursor의 증발 문제 등이 그것이다. 이러한 문제점을 해결하기 위해 산화아연 나노구조 성장 시, 마그네슘(Mg)을 도입하여, 각 원소의 조성 차이에 따라 기판 표면에 30nm 두께 미만의 상분리층(단결정+비정질층)을 자발적으로 형성시켰다. 성장이 진행됨에 따라, 아연이 rich한 단결정 층에서는 나노선이 선택적으로 성장하게 하였고, 마그네슘이 rich한 비정질 층에서는 성장이 이루어지지 않게 하였다. 따라서 산화아연이 증발되는 온도영역에서 10nm 이하 직경을 가지는 나노선을 자발적으로 계면층 없이 수직 성장하였다. 또한, 표면의 단결정, 비정질의 사이즈를 Mg 유량으로 적절히 조절한 결과, 산화아연계 나노월 구조성장이 가능하였다.

• Korean Journal of Materials Research
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• v.5 no.7
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• pp.794-801
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• 1995

To connect the driver IC and Al coated glass, a method has been developed to plate electrolessly Ni on Al/PR system. It Is necessary to pretreat Al to remove oxide film before plating. In order to find pretreatment process which does not damage photoresist or glass, alkaline and fluoride zincate process have been investigated. Because photoresist and aluminum thin film can easily dissolve in alkaline solution, it is considered that the fluoride zincate process was a suitable one. After immersion in the zincate solution containing 1.5 g/$\ell$ ammonium bifluoride and 100 g/$\ell$ zinc sulfate, electroless nickel plating could be performed. The additive in the zincate solution and thiourea in the plating solution increased smoothness of the plated surface. Acld dip could improve the uniformit of the surface.

• Journal of Powder Materials
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• v.26 no.1
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• pp.1-5
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• 2019

In this study, porous Mo-5 wt% Cu with unidirectionally aligned pores is prepared by freeze drying of camphene slurry with $MoO_3-CuO$ powders. Unidirectional freezing of camphene slurry with dispersion stability is conducted at $-25^{\circ}C$, and pores in the frozen specimens are generated by sublimation of the camphene crystals. The green bodies are hydrogen-reduced at $750^{\circ}C$ and sintered at $1000^{\circ}C$ for 1 h. X-ray diffraction analysis reveals that $MoO_3-CuO$ composite powders are completely converted to a Mo-and-Cu phase without any reaction phases by hydrogen reduction. The sintered bodies with the Mo-Cu phase show large and aligned parallel pores to the camphene growth direction as well as small pores in the internal walls of large pores. The pore size and porosity decrease with increasing composite powder content from 5 to 10 vol%. The change of pore characteristics is explained by the degree of powder rearrangement in slurry and the accumulation behavior of powders in the interdendritic spaces of solidified camphene.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.1
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• pp.25-29
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• 2019

Various process technologies for manufacturing power inductors are under development. The core goal is to increase the mixing ratio of the soft magnetic powder in the epoxy, and to uniformly disperse it in a molding-type power inductor, manufactured by the injection molding method. In this study, we investigated the effect of dispersant and silane on the dispersion of soft magnetic metal powders in epoxy. We added 0.6 wt% of dispersant and 2.0 wt% of silane, and an excellent dispersibility resulted. Under the conditions of 0.3 wt% of dispersant and 0.5 wt% of silane, we added both dispersant and silane together to observe the effect of their interaction on dispersibility. Similarly, the addition of 0.3 wt% of dispersant and 0.1 wt% of silane resulted in a sharp increase in viscosity, considered to be due to the interaction of the dispersant and silane. The addition of 0.1 wt% of dispersant with 0.5 wt% of silane resulted in a sharp rise in viscosity, and sedimentation-height decreased sharply due to the dispersion optimization.

• Korean Journal of Materials Research
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• v.33 no.2
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• pp.63-70
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• 2023

In this study, crystallization was effectively suppressed in Al-based metallic glasses (Al-MGs) during pulverization by cryo-milling by applying an extremely low processing temperature and using a surfactant. Before Al-MGs can be used as an additive in Ag paste for solar cells, the particle sizes of the Al-MGs must be reduced by milling. However, during the ball milling process crystallization of the Al-MG is a problem. Once the Al-MG is crystallized, they no longer exhibit glass-like behavior, such as thermoplastic deformation, which is critical to decrease the electrical resistance of the Ag electrode. The main reason for crystallization during the ball milling process is the heat generated by collisions between the particles and the balls, or between the particles. Once the heat reaches the crystallization temperature of the Al-MGs, they start crystallization. Another reason for the crystallization is agglomeration of the particles. If the initially fed particles become severely agglomerated, they coalesce instead of being pulverized during the milling. The coalesced particles experience more collisions and finally crystallize. In this study, the heat generated during milling was suppressed by using cryo-milling with liquid-nitrogen, which was regularly fed into the milling jar. Also, the MG powders were dispersed using a surfactant before milling, so that the problem of agglomeration was resolved. Cryo-milling with the surfactant led to D50 = 10 um after 6 h milling, and we finally achieved a specific contact resistance of 0.22 mΩcm² and electrical resistivity of 2.81 μΩcm using the milled MG particles.

• Applied Chemistry for Engineering
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• v.22 no.6
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• pp.672-678
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• 2011

In this work, carbon fibers were electrolessly Ni-plated in order to investigate the effect of metal plating on the electromagnetic shielding effectiveness (EMI-SE) of Ni-coated carbon fibers-reinforced epoxy matrix composites. The surfaces of carbon fibers were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Electric resistance of the composites was tested using a 4-point-probe electric resistivity tester. The EMI-SE of the composites was evaluated by means of the reflection and adsorption methods. From the results, it was found that the EMI-SE of the composites enhanced with increasing Ni plating time and content. In high frequency region, the EMI-SE didn't show further increasing with high Ni content (Ni-CF 10 min) compared to the Ni-CF 5 min sample. In conclusion, Ni content on the carbon fibers can be a key factor to determine the EMI-SE of the composites, but there can be an optimized metal content at a specific electromagnetic frequency region in this system.