• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.111-111
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• 2010

최근 전자 소자의 집적기술은 기존의 2차원에서 System on package (SOP) 개념에 기반을 둔 3차원 집적 기술로 발전 되어가고 있다. 소자의 3차원 실장을 실현시키는 과정에서 세라믹의 여러 유용성이 언급되어져 왔지만, 취성이 매우 크다는 등의 단점이 있었다. 이러한 이유로 연성을 가지는 폴리머와 세라믹을 합성한 복합체 기판에 대하여 많은 연구가 되고 있다. 그러나 세라믹 제작을 위해서는 높은 공정온도가 요구되고 있고 이러한 높은 공정상에서의 온도는 3차원 실장에 있어서 문제점이 되고 있다. 이러한 문제점을 극복하기 위하여 상온에서 치밀한 세라믹 후막을 제작할 수 있는 공정인 Aerosol Deposition Method (ADM)방법으로 세라믹-폴리머 후막의 제조를 시도하였다. 일반적으로 ADM은 수백 나노의 출발 파우더를 사용하여 치밀한 세라믹 막을 형성하는데 사용된다. 본 연구에서는 ADM으로 100 nm미만의 나노 세라믹 파우더를 사용하여 다공성의 세라믹 후막을 제조한 후 resin을 함침시키는 방법으로 세라믹-폴리머 후막의 제조를 시도하였다. 그 결과 운송가스, aerosol 농도 등의 공정조건을 변화시켜 다공성의 $Al_2O_3$ 후막을 제조하였고, 이 다공성 후막은 반투명의 특성을 보이며 고충전율로 형성되었다. 이렇게 제조된 나노 다공성 $Al_2O_3$ 후막에 cyanate ester resin을 함침시키는 방법을 사용하여 $Al_2O_3$-cyanate ester 복합체 후막을 제조하였으며, 이의 비유전율 및 품질계수는 각각 1 MHz에서 6.7, 1000으로 우수한 유전특성을 보임이 확인되었다.

• Journal of Plant Biotechnology
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• v.7 no.4
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• pp.219-223
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• 2005

We investigated chemical-wounding effect on Agrobacterium-mediated Chinese cabbage transformation via vacuum infiltration. Pre-germinated or germinating Chinese cabbage seeds were infiltrated with Agrobacterium tumefaciens LBA4404 cells carrying either GUS gene (pBI121) or hepatitis B virus surface antigen DNA (pBIHBsAg). Prior to agroinfiltration process, the seeds were soaked in sodium hydrosulfite (SHS) solution or just in sterile water as a control. Comparative transformation efficiency was determined by both of histochemistry and ELISA. We could demonstrate that SHS solution treatment especially to 1-day or 2-days old germinating seeds efficiently improved transformation process, and therefore, transient expression level. This strongly indicated that Agrobacterium infection could be facilitated indeed by SHS-causing wounds on Chinese cabbage seeds.

• Journal of the Korean Ceramic Society
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• v.32 no.7
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• pp.825-831
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• 1995

Reaction-bonded SiC-Si material was fabricated by infiltration of Si melt into a mixture of $\alpha$-SiC and carbon at 175$0^{\circ}C$ under the vacuum atmosphere. Wear properties were analyzed by ball-on-plate wear tester, changing loading weight, sliding speed, sliding time and atmosphere, Results showed that the friction coefficient was decreased with increasing load and sliding velocity. The lowest friction coefficient of 0.05 was obtained under an oil atmosphere. The analysis of the wear surface indicated that the areas wehre particles were pulled out and where free silicon particles worn out preferentially serve as liquid reservoirs to decrease the wear resistance.

• Journal of the Korean institute of surface engineering
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• v.51 no.6
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• pp.360-364
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• 2018

A facile method to fabricate freestanding CuO nanoleaves and CuO nanowires-based films was demonstrated. $Cu(OH)_2$ nanoleaves and nanowires were prepared by a hydrolysis reaction in aqueous solution including pyridine and NaOH with the tailored concentrations at room temperature. The films of freestanding CuO nanoleaves and CuO nanowires can be successfully obtained via the simple vacuum infiltration following a thermal dehydration reaction. The morphologies and crystallinity of the $Cu(OH)_2$ nanoleaves/nanowires and CuO nanoleaves/nanowires were characterized by XRD, SEM, TEM and FT-IR. The films fabricated with freestanding CuO nanoleaves and nanowires in this study may be applicable for building high-efficiency organic binder-free devices, such as gas sensors, batteries, photoelectrodes for water splitting and so on.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.150-150
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• 2016

Mankind is enjoying a great convenience of their life by the rapid growth of secondary industry since the Industrial Revolution and it is possible due to the invention of huge power such as engine. The automobile which plays the important role of industrial development and human movement is powered by the Engine Module, and especially Diesel engine is widely used because of mechanical durability and energy efficiency. The main work mechanism of the Diesel engine is composed of inhalation of the organic material (coal, oil, etc.), combustion, explosion and exhaust Cycle process then the carbon compound emissions during the last exhaust process are essential which is known as the major causes of air pollution issues in recent years. In particular, COx, called carbon oxide compound which is composed of a very small size of the particles from several ten to hundred nano meter and they exist as a suspension in the atmosphere. These Diesel particles can be accumulated at the respiratory organs and cause many serious diseases. In order to compensate for the weak point of such a Diesel Engine, the DPF(Diesel Particulate Filter) post-cleaning equipment has been used and it mainly consists of ceramic materials(SiC, Cordierite etc) because of the necessity for the engine system durability on the exposure of high temperature, high pressure and chemical harsh environmental. Ceramic Material filter, but it remains a lot of problems yet, such as limitations of collecting very small particles below micro size, high cost due to difficulties of manufacturing process and low fuel consumption efficiency due to back pressure increase by the small pore structure. This study is to test the possibility of new structure by direct infiltration of SiC Whisker on Carbon felt as the next generation filter and this new filter is expected to improve the above various problems of the Ceramic DPF currently in use and reduction of the cost simultaneously. In this experiment, non-catalytic VS CVD (Vapor-Solid Chemical Vaporized Deposition) system was adopted to keep high mechanical properties of SiC and MTS (Methyl-Trichloro-Silane) gas used as source and H2 gas used as dilute gas. From this, the suitable whisker growth for high performance filter was observed depending on each deposition conditions change (input gas ratio, temperature, mass flow rate etc.).

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.51.2-51.2
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• 2015

Understanding interfacial phenomena has been one of the main research issues not only in semiconductors but only in life sciences. I have been trying to meet the atomic scale surface and interface analysis challenges from semiconductor industries and furthermore to extend the application scope to biomedical areas. Optical imaing has been most widely and successfully used for biomedical imaging but complementary ion beam imaging techniques based on mass spectrometry and ion scattering can provide more detailed molecular specific and nanoscale information In this presentation, I will review the 27 years history of medium energy ion scattering (MEIS) development at KRISS and DGIST for nanoanalysis. A electrostatic MEIS system constructed at KRISS after the FOM, Netherland design had been successfully applied for the gate oxide analysis and quantitative surface analysis. Recenlty, we developed time-of-flight (TOF) MEIS system, for the first time in the world. With TOF-MEIS, we reported quantitative compositional profiling with single atomic layer resolution for 0.5~3 nm CdSe/ZnS conjugated QDs and ultra shallow junctions and FINFET's of As implanted Si. With this new TOF-MEIS nano analysis technique, details of nano-structured materials could be measured quantitatively. Progresses in TOF-MEIS analysis in various nano & bio technology will be discussed. For last 10 years, I have been trying to develop multimodal nanobio imaging techniques for cardiovascular and brain tissues. Firstly, in atherosclerotic plaque imaging, using, coherent anti-stokes raman scattering (CARS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) multimodal analysis showed that increased cholesterol palmitate may contribute to the formation of a necrotic core by increasing cell death. Secondly, surface plasmon resonance imaging ellipsometry (SPRIE) was developed for cell biointerface imaging of cell adhesion, migration, and infiltration dynamics for HUVEC, CASMC, and T cells. Thirdly, we developed an ambient mass spectrometric imaging system for live cells and tissues. Preliminary results on mouse brain hippocampus and hypotahlamus will be presented. In conclusions, multimodal optical and mass spectrometric imaging privides overall structural and morphological information with complementary molecular specific information, which can be a useful methodology for biomedical studies. Future challenges in optical and mass spectrometric imaging for new biomedical applications will be discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.281-281
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• 2010

Very low refractive index (<1.4) materials have been proved to be the key factor improving the performance of various optical components, such as reflectors, filters, photonic crystals, LEDs, and solar cell. Highly porous SiO2 are logically designed for ultralow refractive index materials because of the direct relation between porosity and index of refraction. Among them, ordered macroporous SiO2 is of potential material since their theoretically low refractive index ~1.10. However, in the conventional synthesis of ordered macroporous SiO2, the time required for the crystallization of organic nanoparticles, such as polystyrene (PS), from colloidal solution into well ordered template is typical long (several days for 1 cm substrate) due to the low interaction between particles and particle - substrate. In this study, polystyrene - polyacrylic acid (PS-AA) nanoparticles synthesized by miniemulsion polymerization method have hydrophilic polyacrylic acid tails on the surface of particles which increase the interaction between particle and with substrate giving rise to the formation of PS-AA film by simply spin - coating method. Less ordered with controlled thickness films of PS-AA on silicon wafer were successfully fabricated by changing the spinning speed or concentration of colloidal solution, as confirmed by FE-SEM. Based on these template films, a series of macroporous SiO2 films whose thicknesses varied from 300nm to ~1000nm were fabricated either by conventional sol - gel infiltration or gas phase deposition followed by thermal removal of organic template. Formations of SiO2 films consist of interconnected air balls with size ~100 nm were confirmed by FE-SEM and TEM. These highly porous SiO2 show very low refractive indices (<1.18) over a wide range of wavelength (from 200 to 1000nm) as shown by SE measurement. Refraction indices of SiO2 films at 633nm reported here are of ~1.10 which, to our best knowledge, are among the lowest values having been announced.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.202-202
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• 2011

The research of 3-dimensional (3-D) scaffold for tissue engineering has been widely investigated as the importance of the 3-D scaffold increased. 3-D scaffold is needed to support for cells to proliferate and maintain their biological functions. Furthermore, its architecture defines the shape of the new bone and cartilage growth. Polycaprolactone (PCL) has been one of the most promising materials for fabricating 3-D scaffold owing to its excellent mechanical property and biocompatibility. However, there are practical problems for using it, in vitro and in vivo; extracellular matrix components and nutrients cannot penetrate into the inner space of scaffold, due to its hydrophobic property, and thus cell seeding and attachment onto the inner surface remain as a challenge. Thus, the surface modification strategy of 3-D PCL scaffold is prerequisite for successful tissue engineering. Herein, we utilized a mussel-inspired approach for surface modification of 3-D PCL scaffold. Modification of 3-D PCL scaffolds was carried out by simple immersion of scaffolds into the dopamine solution and stimulated body fluid, and as a result, hydroxyapatite-immobilized 3-D PCL scaffolds were obtained. After surface modification, the wettability of 3-D PCL scaffold was considerably changed, and infiltration of the pre-osteoblastic cells into the 3-D scaffold followed by the attachment onto the surface was successfully achieved.

• 보존과학연구
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• s.8
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• pp.13-34
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• 1987

A large number of metallic relics were excavated by a team of Kyungsang University museum (Nov. 25, 1985 - Jan. 29, 1986) from the groups of tombs located at No. 9 Mountain,Okchun Village, Sungsan-Ri, Ssangchak-Myon, Hyopchun-Kun, Kyungsangnam-Do which are believed to date back to Kaya period. The Research Institute of Cultural Properties was in charge performing scientific conservation and restoration for the iron cuirass and horse halmet (for one year and seven months, Feb. '86 - Sep. '87)The scientific processing for them are as follows :1. Taken Photo and record the actual conditions prior to conservation.2. Taken radiography3. Elimate Goethite ($\alpha$-FeOOH) layer on the surface using Air-brasive, remaining Magnetite ($Fe_3O_4$) layer.4. Treat to dechlorinize with 3% Sodium-Sesquicarbonate5. Protected the relics with Ruscoat acryl resin using vacuum infiltration method.6. Joint the sherd using Araldite and Microballoon mixture.7. Restored missing parts by Araldite SV 427 and HV 4278. Made record and taken photo after restoration Several hundred of sherds of relics, small or large, were restored by assortment which this method for the purpose of contributing to the further study of ancient Kaya history.* Conservator, National Research Institute of Cultural Properties.

• KSBB Journal
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• v.21 no.6 s.101
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• pp.489-492
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• 2006

For molecular breeding purpose, genetic transformation of Brassica napus cultivars has been extensively performed using Agrobacterium method. B. napus cv. napus, one of major oil crops, can be transformed via Agrobacterium-based method. We demonstrated that Agrobacterium-mediated transformation via vacuum infiltration slightly worked for the seedlings of B. napus cv. napus according to fluorometric GUS enzyme analysis. In contrast, transformation efficiency was highly enhanced when the seedlings, prior to agroinfiltration, were treated with sodium hydrosulfite solution as a chemical wounding agent. GUS gene expression in transformed seedlings that was confirmed by RT-PCR suggests their usefulness for the development of transient expression system.