• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.2
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• pp.224-234
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• 2013

This study investigates the fabrication of core-sheath nanocomposite fibers by locating germanium (Ge) and silicon dioxide ($SiO_2$) nanoparticles selectively in the sheath layer by co-axial electrospinning. Co-axially spun fibers were prepared by electrospinning a pure PVA solution and Ge/$SiO_2$/PVA solution as the core and sheath layer, respectively. Core-sheath nanocomposite fibers were electrospun under a variety of conditions that include various feed rates for the core and sheath solutions, voltages, and concentric needle diameters, in order to find an optimum spinning condition. Ge/$SiO_2$ nanocomposite fibers were also prepared by uniaxial electrospinning to compare fiber morphology and nanoparticle distribution with core-sheath nanofibers. Using scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray analysis, it was demonstrated that the co-axial approach resulted in the presence of nanoparticles near the surface region of the fibers compared to the overall distribution obtained for uni-axial fibers. The co-axially electrospun Ge/$SiO_2$/PVA nanofiber webs have possible uses in high efficiency functional textiles in which the nanoparticles located in the sheath region provide enhanced functionality.

• Prospectives of Industrial Chemistry
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• v.22 no.6
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• pp.41-58
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• 2019

다공성 실리콘 나노 입자는 약물 전달과 바이오이미징 등 의생명공학 분야에 다양하게 활용할 수 있는 가능성을 지닌 소재이다. 실리콘 원소 특유의 생분해성, 발광 효과, 다공성 구조 형성을 통한 약물 전달 기능에 이르는 다양한 특성으로 인해 미래 중개의학 플랫폼으로 각광 받고 있으며, 특히 바이오이미징 분야에서의 활용성이 매우 주목 받고 있다. 이에 대한 최신 연구 동향을 보고하고자, 다공성 실리콘 나노 입자의 제작 및 바이오이미징 응용 연구에 대한 성과를 소개한다. 바이오이미징을 위한 핵심 요소인 발광 특성(근적외선 방출, 마이크로 초 단위의 감쇄 시간 등)에 대한 논의를 바탕으로 최근 연구 성과 및 약물 전달 과정 모니터링 기능 등 다방면의 응용 가능성에 대한 방향을 소개한다. 실리콘 나노 입자의 제작 및 표면 화학 반응을 통한 기능성 제어, 이를 활용한 바이오이미징 연구 동향에 대한 전략도 광범위하게 제시하고자 한다.

• Journal of Powder Materials
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• v.25 no.5
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• pp.402-407
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• 2018

Molybdenum silicide has gained interest for high temperature structural applications. However, poor fracture toughness at room temperatures and low creep resistance at elevated temperatures have hindered its practical applications. This study uses a novel powder metallurgical approach applied to uniformly mixed molybdenum silicide-based composites with silicon carbide. The degree of powder mixing with different ball milling time is also demonstrated by Voronoi diagrams. Core-shell composite powder with Mo nanoparticles as the shell and ${\beta}-SiC$ as the core is prepared via chemical vapor transport. Using this prepared core-shell composite powder, the molybdenum silicide-based composites with uniformly dispersed ${\beta}-SiC$ are fabricated using pressureless sintering. The relative density of the specimens sintered at $1500^{\circ}C$ for 10 h is 97.1%, which is similar to pressure sintering owing to improved sinterability using Mo nanoparticles.

• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.201-201
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• 2018

• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.577-581
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• 2011

Silicon nanoparticles have attracted a great deal of scientific interests due to its intense photoluminescence in the visible spectral region and its potential applications in biological fluorescence maker, RGB (red, green, blue) display, photonics and photovoltaics etc. Practical applications making use of optical and physicochemical properties of Si nanoparticles requires an efficient synthetic method which allows easy modulation of their size, size distribution as well as surface functionalities etc. In this study, a one-pot solution reduction scheme is attempted to prepare alkyl-terminated Si nanoparticles (<10 nm) with Si precursors, (Octyl)$SiCl_3$ or mixture of (Octyl)$SiCl_3$ and $SiCl_4$, containing alkyl-groups using Na(naphthalide) as reducing agent. The surface capping of Si nanoparticles with octyl-groups as well as Si nanoparticle formation was achieved in one-pot reaction. The hexane soluble Si nanoparticles with octyl-termination were in the range of 2-10 nm by TEM and some oxide groups (Si-O-Si) was present on the surface by EDS/FTIR analyses. The optical properties of Si nanoparticles measured by UV-vis and PL evidenced that photoluminescent Si nanoparticles with alkyl-termination was successfully synthesized by solution reduction of alkyl-containing Si precursors in one-pot reaction.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1538-1541
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• 2009

Amphiphobic thin films for touched panel application was prepared by $SiO_2$ nanoparticles self-assembled nanostructure. Silicon dioxide nano spheres were prepared by sol-gel method and well dispersed in a solution with surfacants of low surface energy. Nanostrcture thin films were obtained by spin coating technologies.

• Journal of the Korean Ceramic Society
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• v.49 no.4
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• pp.352-362
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• 2012

This paper explores the use of a variety of carbon nanoparticles to impart electrical, thermal conductivity, good frictional properties to silicon nitride matrices. We used the highly promising types of carbon as carbon nanotubes, exfoliated graphene and carbon black nanograins. A high-efficiency attritor mill has also been used for proper dispersion of second phases in the matrix. The sintered silicon nitride composites retained the mechanical robustness of the original systems. Bending strength as high as 700 MPa was maintained and an electrical conductivity of 10 S/m was achieved in the case of 3 wt% multiwall carbon nanotube addition. Electrically conductive silicon nitride ceramics were realized by using carbon nanophases. Examples of these systems, methods of fabrication, electrical percolation, mechanical, thermal and tribological properties are discussed.

• Analytical Science and Technology
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• v.22 no.3
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• pp.247-253
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• 2009

Porous silicon films are electrochemically etched from crystalline silicon wafers in an aqueous solution of hydrofluoric acid(HF). Careful control of etching conditions (current density, etch time, HF concentration) provides films with precise, reproducible physical parameters (morphology, porosity and thickness). The etched pattern could be varied due to (1) current density controls pore size (2) etching time determines depth and (3) complex layered structures can be made using different current profiles (square wave, triangle, sinusoidal etc.). The optical interference spectrum from Fabry-Perot layer has been used for forensic applications, where changes in the optical reflectivity spectrum confirm the identity. We will explore a method of identifying the specific pattern code and can be used for identities of individual code with porous silicon based encoded nanosized smart particles.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.5-13
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• 2023

In this study, a comparative study is conducted on the synthesis methods for silica nanoparticle employing the silicon sludge waste generated from the semiconductor manufacturing processes. Specifically, acid-washed silicon sludge wastes with no impurities are employed as the precursors of sol-gel and hydrothermal methods for silica nanoparticles preparation. The morphologies and properties of silica nanoparticles synthesized via two synthetic methods are examined by various analysis methods. As a result, silica nanoparticles from the sol-gel method are fabricated with high purity and uniform shape, while the hydrothermal method exhibits advantages in yield and ease of synthetic process. This comparative study offers detailed experimental results on the two synthetic methods for silica nanoparticle synthesis, which may contribute to the establishment of manufacturing high-value materials using the by-products generated in the semiconductor process.

• Journal of the Korean Electrochemical Society
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• v.13 no.1
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• pp.70-74
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• 2010

The immobilization of proteins on silicon surfaces using electrochemical reaction has been studied. Chemical deposition of nitrobenzendiazonium (NiBD) cations is employed to modify silicon surfaces. Electrochemical reduction of nitro-group to primary amine-group have been conducted on the modified surfaces to activate silicon surfaces for the protein immobilization. Attachment of gold nanoparticles was used to prove the reduction. The current method was applied to selective activation of a silicon nanowire and immobilize proteins on the selected nanowire. It has been demonstrated that the use of chemical and electrochemical reaction NiBD is efficient for the selective immobilization of proteins on silicon nanowire surfaces.