Light-weight ceramic insulation materials and high-emissivity coatings were fabricated for reusable thermal protection systems (TPS). Alumina-silica fibers and boric acid were used to fabricate the insulation, which was heat treated at 1250 °C. High-emissivity coating of borosilicate glass modified with TaSi2, MoSi2, and SiB6 was applied via dip-and-spray coating methods and heat-treated at 1100°C. Testing in a high-velocity oxygen fuel environment at temperatures over 1100 °C for 120 seconds showed that the rigid structures withstood the flame robustly. The coating effectively infiltrated into the fibers, confirmed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction analyses. Although some oxidation of TaSi2 occurred, thereby increasing the Ta2O5 and SiO2 phases, no significant phase changes or performance degradation were observed. These results demonstrate the potential of these materials for reusable TPS applications in extreme thermal environments.

목적: 본 연구는 노인을 대상으로 한 디지털 리터러시 중재의 형태, 방법, 중재 결과를 도출하기 위해 설정한 종속 변수와 평가도구, 중재의 효과에 대해 알아보고자 하였다. 연구방법: 문헌 검색은 국외 데이터베이스인 PubMed, Web of Science, EBSCOhost, Medline, Embase를 활용하였다. 연구 기간은 제한하지 않았으며, 검색어는 (“Digital literacy” OR “Digital capability” OR “Media literacy” OR “Digital competencies” OR “Information and Communication Technology”) AND (‘Elderly’ OR “Older adult” OR ‘Geriatric’ OR ‘Senior’ OR ‘Aged’) AND (‘Intervention’ OR ‘Practice’ OR ‘Training’ OR ‘Education’ OR ‘Program’ OR ‘Learning’) 사용하였다. 결과: 최종 분석 대상 연구는 총 8편이었으며, 질적 수준은 무작위 실험 대조군 연구 1편, 두 집단 비무작위 실험 대조군 연구 6편, 단일 집단 비무작위 연구 1편이었다. 연구에서 설정한 종속변수는 디지털 리터러시가 가장 많았으며, 중재는 집단과 개별 형태로 제공되었다. 중재에는 컴퓨터, 핸드폰, 태블릿 등의 디지털 기기가 사용되었고, 중재의 효과는 디지털 리터러시, 우울감, 자기 효능감, 삶의 만족 등에서 유의미한 변화를 보인 것으로 나타났다. 결론: 본 연구는 노인의 디지털 리터러시 증진을 위한 중재 개발과 연구의 방향성을 제시하고자 하였다. 향후에는 체계적인 연구설계를 기반으로 높은 질적 수준의 연구와 디지털 리터러시 중재가 노인에게 미치는 다양한 영향에 대한 검증이 이루어져야 할 것이다.

YSZ (Y2O3-stabilized zirconia)-based ceramics have excellent mechanical properties, such as high strength and wear resistance. In the application, YSZ is utilized in the bead mill, a fine-grinding process. YSZ-based parts, such as the rotor and pin, can be easily damaged by continuous application with high rpm in the bead mill process. In that case, adding WC particles improves the tribological and mechanical properties. YSZ-30 vol.% WC composite ceramics are manufactured via hot pressing under different pressures (10/30/60 MPa). The hot-pressed composite ceramics measure the physical properties, such as porosity and bulk density values. In addition, the phase formation of these composite ceramics is analyzed and discussed with those of physical properties. For the increased applied pressure of hot pressing, the tetragonality of YSZ and the crystallinity of WC are enhanced. The mechanical properties indicate an improved tendency with the increase in the applied pressure of hot pressing.

Thermal protection systems (TPS) are a group of materials that are indispensable for protecting spacecraft from the aerodynamic heating occurring during entry into an atmosphere. Among candidate materials for TPS, ceramic insulation materials are usually considered for reusable TPS. In this study, ceramic insulation materials, such as alumina enhanced thermal barrier (AETB), are fabricated via typical ceramic processing from ceramic fiber and additives. Mixtures of silica and alumina fibers are used as raw materials, with the addition of B4C to bind fibers together. Reaction-cured glass is also added on top of AETB to induce water-proof functionality or high emissivity. Some issues, such as the elimination of clumps in the AETB, and processing difficulties in the production of reusable surface insulation are reported as well.

3Y-TZP ceramics obtained by doping 3 mol.% of Y2O3 to ZrO2 to stabilize the phase transition are widely used in the engineering ceramic industry due to their excellent mechanical properties such as high strength, fracture toughness, and wear resistance. An additional increase in mechanical properties is possible by manufacturing a composite in which a high-hardness material such as oxide or carbide is added to the 3Y-TZP matrix. In this study, composite powder was prepared by dispersing a designated percentage of WC in the 3Y-TZP matrix, and the results were compared after manufacturing the composite using the different processes of spark plasma sintering and HP. The difference between the densification behavior and porosity with the process mechanism was investigated. The correlation between the process conditions and phase formation was examined based on the crystalline phase formation behavior. Changes to the microstructure according to the process conditions were compared using field-emission scanning electron microscopy. The toughness-strengthening mechanism of the composite with densification and phase formation was also investigated.

SiAlON-based ceramics are a type of oxynitride ceramics, which can be used as cutting tools for heatresistant super alloys (HRSAs). These ceramics are derived from Si3N4 ceramics. SiAlON can be densified using gaspressure reactive sintering from mixtures of oxides and nitrides. In this study, we prepare an α-/β-SiAlON ceramic composite with a composition of Yb0.03Y0.10Si10.6Al1.4O1.0N15.0. The structure and mechanical/thermal properties of the densified SiAlON specimen are characterized and compared with those of a commercial SiAlON cutting tool. By observing the crystallographic structures and microstructures, the constituent phases of each SiAlON ceramic, such as α- SiAlON, β-SiAlON, and intergranular phases, are identified. By evaluating the mechanical and thermal properties, the contribution of the constituent phases to these properties is discussed as well.

Zirconia has excellent mechanical properties, such as high fracture toughness, wear resistance, and flexural strength, which make it a candidate for application in bead mills as milling media as well as a variety of components. In addition, enhanced mechanical properties can be attained by adding oxide or non-oxide dispersing particles to zirconia ceramics. In this study, the densification and mechanical properties of YSZ-TiC ceramic composites with different TiC contents and sintering temperatures are investigated. YSZ - x vol.% TiC (x=10, 20, 30) system is selected as compositions of interest. The mixed powders are sintered using hot pressing (HP) at different temperatures of 1300, 1400, and 1500oC. The densification behavior and mechanical properties of sintered ceramics, such as hardness and fracture toughness, are examined.

SiAlON ceramics are used as ceramic cutting tools for heat-resistant super alloys (HRSAs) due to their excellent fracture toughness and thermal properties. They are manufactured from nitride and oxide raw materials. Mixtures of nitrides and oxides are densified via liquid phase sintering by using gas pressure sintering. Rare earth oxides, when used as sintering additives, affect the color and mechanical properties of SiAlON. Moreover, these sintering additives influence the cutting performance. In this study, we have prepared Ybm/3Si12-(m+n)Alm+nOnN16-n (m = 0.5; n = 0.5, 1.0) ceramics and manufactured SiAlON ceramics, which resulted in different colors. In addition, the characteristics of the sintered SiAlON ceramics such as fracture toughness and microstructure have been investigated and results of the cutting test have been analyzed.

SiAlON-based ceramics are some of the most typical ceramic materials used as cutting tools for HRSA(Heat Resistant Super-Alloys). SiAlON can be fabricated using ceramic processing, such as mixing, granulation, compaction, and sintering. Spray drying is a widely-used method for producing a granular powder of controlled morphology and size with flowability. In this study, we report a systematic investigation aimed at optimizing spherical granule morphology by controlling spray-drying parameters such as gas flow and feed rate. Before spray drying, the viscosities of the raw material slurries were also optimized with the amount of dispersant added.

Reaction-bonded silicon carbide (RBSC) is a SiC-based composite ceramic fabricated by the infiltration of molten silicon into a skeleton of SiC particles and carbon, in order to manufacture a ceramic body with full density. RBSC has been widely used and studied for many years in the SiC field, because of its relatively low processing temperature for fabrication, easy use in forming components with a near-net shape, and high density, compared with other sintering methods for SiC. A radiant tube is one of the most commonly employed ceramics components when using RBSC materials in industrial fields. In this study, the mechanical strengths of commercial RBSC tubes with different sizes are evaluated using 3-point flexural and C-ring tests. The size scaling law is applied to the obtained mechanical strength values for specimens with different sizes. The discrepancy between the flexural and C-ring strengths is also discussed.

SiAlON-based ceramics are some of the most typical oxynitride ceramic materials, which can be used as cutting tools for heat-resistant super-alloys (HRSA). SiAlON can be fabricated by using gas-pressure reactive sintering from the raw materials, nitrides and oxides such as Si3N4, AlN, Al2O3, and Yb2O3. In this study, we fabricate Ybm/3Si12-(m+n)Alm+nOnN16-n (m=0.3, n=1.9, 2.3, 2.7) ceramics by using gas-pressure sintering at different sintering temperatures. Then, the densification behavior, phase formation, microstructure, and hardness of the sintered specimens are characterized. We obtain a fully densified specimen with β- SiAlON after gas-pressure sintering at 1820℃ for 90 min. under 10 atm N2 pressure. These SiAlON ceramic materials exhibited hardness values of ~92.9 HRA. The potential of these SiAlON ceramics for cutting tool application is also discussed.

Rare-earth zirconates, such as lanthanum zirconates and gadolinium zirconates, have been intensively investigated due to their excellent properties of low thermal conductivity as well as chemical stability at high temperature, which can make these materials ones of the most promising candidates for next-generation thermal barrier coating applications. In this study, three compositions, lanthanum/gadolinium zirconates with reduced rare-earth contents from stoichiometric RE2Zr2O7 compositions, are fabricated via solid state reaction as well as sintering at 1600oC for 4 hrs. The phase formation, microstructure, and thermo-physical properties of three oxide ceramics are examined. In particular, each oxide ceramics exhibits composite structures between pyrochlore and fluorite phases. The potential of lanthanum/ gadolinium zirconate ceramics for TBC applications is also discussed.

Lanthanum zirconate, La2Zr2O7, is one of the most promising candidates for next-generation thermal barrier coating (TBC) applications in high efficient gas turbines due to its low thermal conductivity and chemical stability at high temperature. In this study, bulk specimens and thermal barrier coatings are fabricated via a variety of sintering processes as well as suspension plasma spray in lanthanum zirconates with reduced rare-earth contents. The phase formation, microstructure, and thermo-physical properties of these oxide ceramics and coatings are examined. In particular, lanthanum zirconates with reduced rare-earth contents in a La2Zr2O7-4YSZ composite system exhibit a single phase of fluorite or pyrochlore after fabricated by suspension plasma spray or spark plasma sintering. The potential of lanthanum zirconate ceramics for TBC applications is also discussed.

오늘날 게임 산업의 발달과 함께 다양한 디지 털 콘텐츠가 생성되고 있다. 특히 우리나라에서는 지난 2000년 이후로 컴퓨터 네트워크 기반 시설 의 확충과 PC방의 등장, 속칭 ‘국민게임’이라고 일컬어지던 ‘스타크래프트’의 등장으로 관련 산업 이 급격하게 성장하였다. 그 이후 방송사업자는 게임물을 기반으로 기획한 ‘e-스포츠 경기 영상’ 을 제작하여 인기몰이를 하였다. 또한 인터넷 네 트워크를 이용한 동영상 전문 사이트(Youtube 등) 또는 개인 블로그 등 사설 플랫폼 사업이 활 성화되면서, 게임 이용자인 플레이어 개인들이 스 스로 게임물을 활용한 창작을 하기에 이르렀다. 그러나 게임 플레이어가 제작한 영상물에 대하 여는 그 저작물성에 대한 논의가 극도로 제한된 조건 하에서의 판단이거나 오래되었으며, 단지 원저작물인 게임물의 내용이 반영되었을 뿐이라 는 이유로 저작물성을 인정하지 않는다. 하지만 오늘날에 들어서 상황이 바뀌었음에도 불구하고, 관련 연구나 법원의 판례 또한 드물어 권리관계 가 명확하지 않은 실정이다. 따라서 본 논문에서 는 게임기반영상물의 저작물성과 게임물과의 권 리관계를 명확화하기 위한 목적으로 법적 상태를 논의하며 모델을 제시하고, 그 제작에 주도적 역 할을 한 게임 플레이어의 법적 지위를 살펴보고자 한다.

RBSC (reaction-bonded silicon carbide) represents a family of composite ceramics processed by infiltrating with molten silicon into a skeleton of SiC particles and carbon in order to fabricate a fully dense body of silicon carbide. RBSC has been commercially used and widely studied for many years, because of its advantages, such as relatively low temperature for fabrication and easier to form components with near-net-shape and high relative density, compared with other sintering methods. In this study, RBSC was fabricated with different size of SiC in the raw material. Microstructure, thermal and mechanical properties were characterized with the reaction-sintered samples in order to examine the effect of SiC size on the thermal and mechanical properties of RBSC ceramics. Especially, phase volume fraction of each component phase, such as Si, SiC, and C, was evaluated by using an image analyzer. The relationship between microstructures and physical properties was also discussed.

For the last decade many bridges and buildings have experienced flexural strengthening with the fiber reinforced polymer(FRP) bonding system, demands for increasing heavy traffic loads and the changing of the code application. Of the many strengthening systems, NSM(near surface mounted) system with FRP has become attractive and popular way of strengthening for the existed RC structures and many studies and applications of this technique have significantly increased all over the world. Meanwhile, polymer mortar that contains much of the same ingredients as cement but includes the addition of certain polymer resins for enhancing desired physical properties, has been used as an alternative adhesive. This paper focuses on flexural behaviour of CFRP-bar NSM system with variables such as kinds of adhesive, anchorage, sectional aspect ratio. Based on the test results and test-to -predicted ratio, this paper provides researchers and practical engineers a fundamental knowledge and intuition.

The effects of particle size of Li-Si alloy and LiCl-KCl addition as a binder phase for raw material of anode were investigated on the formability of the thermal battery anode. The formability was evaluated with respect to filling density, tap density, compaction density, spring-back and compressive strength. With increasing particle size of Li-Si alloy powder, densities increased while spring-back and compressive strength decreased. Since the small spring-back is beneficial to avoiding breakage of pressed compacts, larger particles might be more suitable for anode forming. The increasing amount of LiCl-KCl binder phase contributed to reducing spring-back, improving the formability of anode powder too. The control of particle size also seems to be helpful to get double pressed pellets, which consisted of two layer of anode and electrolyte.

FeS2 has been widely used for cathode materials in thermal battery because of its high stability and currentcapability at high operation temperature. Salts such as a LiCl-KCl were added as a binder for improving electrical per-formance and formability of FeS2 cathode powder. In this study, the effects of the addition of Li2O in LiCl-KCl binderon the formability of FeS2 powder compact were investigated. With the increasing amount of Li2O addition to LiCl-KClbinder salts, the strength of the pressed compacts increased considerably when the powder mixture were pre-heat-treatedabove 350oC. The heat-treatment resulted in promoting the coating coverage of FeS2 particles by the salts as Li2O wasadded. The observed coating as Li2O addition might be attributed to the enhanced wettability of the salt rather than itsreduced melting temperature. The high strength of compacts by the Li2O addition and pre-heat-treatment could improvethe formability of FeS2 raw materials.

4 mol% Yttria-stabilized zirconia (4YSZ) coatings with 200 μm thick are fabricated by Electron Beam Physical Vapor Deposition (EB-PVD) for thermal barrier coating (TBC). 150 μm of NiCrAlY based bond coat is prepared by conventional APS (Air Plasma Spray) method on the NiCrCoAl alloy substrate before deposition of top coating. 4 mol% YSZ top coating shows typical tetragonal phase and columnar structure due to vapor phase deposition process. The adhesion strength of coating is measured about 40 MPa. There is no delamination or cracking of coatings after thermal cyclic fatigue and shock test at 850oC.

Lanthanum/gadolinium zirconate coatings are deposited via suspension plasma spray with suspensions fabricated by a planetary mill and compared with hot-pressed samples via solid-state reaction. With increase in processing time of the planetary mill, the mean size and BET surface area change rapidly in the case of lanthanum oxide powder. By using suspensions of planetary-milled mixture between lanthanum or gadolinium oxide and nano zirconia, dense thick coatings with fully-developed pyrochlore phases are obtained. The possibilities of these SPS-prepared coatings for TBC application are also discussed.