• 한국입자에어로졸학회지
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• 제14권3호
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• pp.49-63
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• 2018

During the last decade, electrospray (ES) techniques have been used as potential methods for preparing of core-shell materials. Depending on the architecture of nozzle and design of devices, the ES techniques includes monoaxial, coaxial, multiple coaxial nozzle ES and microfluidic ES devices. ES operates based on a basic principle, in which a spray of monodisperse droplets is formed by dispensing an electrically conductive liquid through a capillary charged to a sufficiently high potential. In review of many recent research papers, we take a closer look at ES techniques and their applications for fabrication of core-shell materials. Several advantages of ES technique compared with other methods were emphasized and it may be regarded as a potential tool for fabrication of core-shell materials current and near future.

• 한국전기전자재료학회논문지
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• 제32권6호
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• pp.522-527
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• 2019

In order to fabricate high-quality SiC substrates for power electronic devices, various single crystal growing methods were prepared. These include the physical vapor transport (PVT) and top seeded solution growth (TSSG) methods. All the suggested SiC growth methods generally use induction-heating furnaces. The temperature distribution in this system can be easily adjusted by changing the hot-zone design. Moreover, precise temperature control in the induction-heating furnace is favorably required to grow a high-quality crystal. Therefore, in this study, we analyzed the heat transfer in these furnaces to grow SiC crystals. As the growth temperature of SiC crystals is very high, we evaluated the effect of radiation heat transfer on the temperature distribution in induction-heating furnaces. Based on our simulation results, a heat transfer strategy that controls the radiation heat transfer was suggested to obtain the optimal temperature distribution in the PVT and TSSG methods.

• 한국분말재료학회지
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• 제24권3호
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• pp.216-222
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• 2017

Synthesized monocrystalline nanodiamond (nD) particles are heat-treated at various temperatures to produce highly structured diamond crystals. The heat-treated nDs show different weight loss ratios during thermogravimetric analysis. The crystallinities of the heat-treated nDs are analyzed using Raman spectroscopy. The average particle sizes of the heat-treated nDs are measured by a dynamic light scattering (DLS) system and direct imaging observation methods. Moreover, individual dispersion behaviors of the heat-treated nD particles are investigated based on ultrasonic dispersion methods. The average particle sizes of the dispersed nDs according to the two different measurement methods show very similar size distributions. Thus, it is possible to produce highly crystallized nD powder particles by a heat-treatment process, and the nD particles are relatively easy to disperse individually without any dispersant. The heat-treated nDs can lead to potential applications such as in nanocomposites, quantum dots, and biomedical materials.

• 한국표면공학회지
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• 제56권4호
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• pp.259-264
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• 2023

As the demand for lithium-ion batteries, a key power source in electric vehicles and energy storage systems, continues to increase for achieving global carbon neutrality, there is a growing concern about the environmental impact of disposing of spent batteries. Extensive research is underway to develop efficient recycling methods. While hydrometallurgy and pyrometallurgy methods are commonly used to recover valuable metals from spent cathode materials, they have drawbacks including hazardous waste and complex processes. Hence, alternative recycling methods that are environmentally friendly are being explored. However, recycling spent cathode materials still remains complex and energy-intensive. This study focuses on a novel approach called solid-state synthesis, which aims at regenerating the performance of spent cathode materials. The method offers a simpler process and reduces energy consumption. Optimal heat treatment conditions were identified based on experimental results, contributing to the development of sustainable recycling technologies for lithium-ion batteries.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.116-116
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• 2003

Most of all nano-structures, SiC had a high electrical conductivity and mechanical strengths ay high temperatures. So It was considered a useful materials for nanosized device materials and added materials for strength hardening. Much methods were developed for SiC nanowire and nanorods like CVD, carbothermal reduction, Laser ablation and CNT-confined reduction. These methods used the VLS (Vapor-Liquid-Solid) growth mechanism. In these experiments, SiC nanowire was grown by SLS (Sold-Liquid-Solid) growth mechanism used Graphite substrate, And we characterized its microstructure to compare with VLS growth mechanism.

• Near Infrared Analysis
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• 제1권2호
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• pp.9-20
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• 2000

Recently, near-infrared (NIR) spectroscopy and Raman spectroscopy have received keen interest as powerful techniques for nondestructive analysis of biological materials. The purpose of this review paper is to compare the advantages of NIR and Raman spectroscopy in the nondestructive analysis. Both methods are quite unique and often complementary. For example. NIR spectroscopy is very useful in monitoring in situ the content of components inside biological materials while Raman spectroscopy is very suitable for identifying micro-components on the surface of biological materials. In this article specific characters of the two spectroscopic methods are discussed first and then several examples of applications of NIR and Raman spectroscopy to the biological nondestructive analysis are introduced.

• 대한건축학회논문집:계획계
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• 제36권5호
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• pp.105-116
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• 2020

In this study, the royal protocols of the Joseon Dynasty, known as uigwes, were reviewed to clarify the materials and structure of Korean traditional walls. For this, the Yeonggeon-and Sanreng-uigwes were thoroughly reviewed, and then the names, materials, and construction methods of the traditional walls were systematically organized. In addition, mix proportions of plastering materials used in the walls were estimated based on the records in the uigwes; these were compared with the ratios specified in the current specifications. As a result of the comprehensive review, it was found that the mix proportions of the plastering materials varied depending on importance of buildings, type of walls, and the raw materials. Based on this, it was concluded that the characteristics of each uigwe should be considered when studying the mix proportion of materials for the traditional walls. It was also found that there were differences between the traditional and modern specifications for the wall constructions. That is, historical records and the specifications currently used were different in terms of constituent materials, construction methods and mix proportions. As a cause of the difference, the disconnection of the traditional methods and the introduction of foreign plastering techniques during the rapid social change in the 20th century were suggested.

• Carbon letters
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• 제22권
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• pp.1-13
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• 2017

Porous materials play a vital role in science and technology. The ability to control their pore structures at the atomic, molecular, and nanometer scales enable interactions with atoms, ions and molecules to occur throughout the bulk of the material, for practical applications. Three-dimensional (3D) porous carbon-based materials (e.g., graphene aerogels/hydrogels, sponges and foams) made of graphene or graphene oxide-based networks have attracted considerable attention because they offer low density, high porosity, large surface area, excellent electrical conductivity and stable mechanical properties. Water pollution and associated environmental issues have become a hot topic in recent years. Rapid industrialization has led to a massive increase in the amount of wastewater that industries discharge into the environment. Water pollution is caused by oil spills, heavy metals, dyes, and organic compounds released by industry, as well as via unpredictable accidents. In addition, water pollution is also caused by radionuclides released by nuclear disasters or leakage. This review presents an overview of the state-of-the-art synthesis methodologies of 3D porous graphene materials and highlights their synthesis for environmental applications. The various synthetic methods used to prepare these 3D materials are discussed, particularly template-free self-assembly methods, and template-directed methods. Some key results are summarized, where 3D graphene materials have been used for the adsorption of dyes, heavy metals, and radioactive materials from polluted environments.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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• pp.211-214
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• 2002

Almost all buildings/infrastructures made of composite materials are fabricated without proper design. Unlike airplane or automobile parts, prototype test is impossible. One cannot destroy 10 story buildings or 100-meter long bridges. People try to build 100-story buildings or several thousand meter long bridges. In order to realize "composites in construction", the following subjects must be studied in detail, for his design. Concept optimization, Simple method of analysis, Folded plate theory, Size effects in failure, and Critical frequency. Unlike the design procedure with conventional materials, his design should include material design, selection of manufacturing methods, and quality control methods, in addition to the fabrication method. In this paper, concept optimization and folded plate theory are presented for practicing engineers.engineers.

• 대한본초학회지
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• 제23권2호
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• pp.9-17
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• 2008

Objectives : The purpose of this report was to provide the information packaging of herbal medicines by analyzing papers. We investigated the packaging materials, packaging methods and expiration date of herbal medicines by analyzing papers of the Korea, Japan and China. Methods : We survey herbal medicine-related law and crude drug monograph of compendium in each three country, we purchased herbal medicine of the Korea, Japan and China in the market and verify the expressed-item in packing paper. In case of Japan, we examine packaging materials, packaging methods, and expiration date of herbal medicine in pharmaceutical company. Results : The pharmaceutical company in japan used the methods of nitrogen gas pouring, vacuum packing for the herbal medicine packaging. The expiration date of the herbal products in Japan is generally 3 to 5 year after packaging. And packaging materials were aluminium and polyethylene. In Korea, pharmaceutical company used airtight packing for the herbal medicine packaging and expiration date of the herbal product were generally 3 year after packaging. Packaging materials were polyethylene, nylon or polyethylene-nylon mixed materials. In China, pharmaceutical company also used airtight packing for the herbal medicine packaging, and the expiration date were generally 5 year after packaging. Packaging materials were polyethylene, wrapping paper-used parcel or tea leaves filter paper. Conclusion : This results can present the basic data for expiration date and preservation methods of the herbal roots in Korea.