• Ceramist
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• 제10권3호
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• pp.28-33
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• 2007

The structural and optical properties of Ni-doped transparent glass-ceramics are reviewed. The quantum efficiencies of ceramics were examined to explore suitable crystalline phase for Ni-doping in glass-ceramics. Inverse spinel $LiGa_5O_8$ have the quantum efficiency of almost 100 % at room temperature. Transparent glass ceramics containing $LiGa_5O_8$ was successfully synthesized by heat treatment of $Li_2O-Ga_2-O_3-SiO_2-NiO$ glass. Most of $Ni^{2+}$ ions in glass-ceramic were incorporated into $LiGa_5O_8$ nanocrystals. The near-infrared emission covering from the O-band to L-band (1260-1625 nm) was observed from the Ni-doped $Li_2O-Ga_2O_3-SiO_2$ glass-ceramic though it was not observed from the as-cast glass. The lifetime of the emission was about $580\;{\mu}sec$ even at 300K. The emission quantum efficiency was evaluated as about 10 % that is enough high for practical usage as gain media of optical fiber amplifiers. The figure of merit (the product of the stimulated emission cross section and lifetime) was as high as that of rare-earth-doped glasses. The broad bandwidth, high quantum efficiency and high figure of merit show that transparent glass-ceramics containing $Ni^{2+}:LiGa_5O_8$ nanocrystals are promising candidates as novel ultra-broadband gain media.

• Journal of Digital Convergence
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• 제19권12호
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• pp.451-456
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• 2021

Advances in science and technology have led the development of the times, and provide abundant technological means, new tools, and new angles of thought to art and new media, and become an important driving force for creativity and rigidity in art. This study, starting from the trend of convergence creativity between art and science and technology, focuses on the new characteristics of new media art, and combines examples of works in several areas such as characteristics. It has a certain reference value for understanding the characteristics of the times and its development trend to deeply grasp the current new media art while analyzing it in detail.

• Journal of Agricultural Extension & Community Development
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• 제7권1호
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• pp.175-180
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• 2000

This experiment was conducts to find out the effects of ceramics mixing on mushrooms mycelial growth and density. It is better ceramics in $800^{\circ}C$ than $1000^{\circ}C$ to mycelial growth and density of Pleurotus astreatus, Flamulina velutepes, Lentinus edodes and Inonotus obliqua . Mycelial growth according to ceramics mixing contents with mushrooms media is good till 0.16% ceramics mixing, but if mycelial growth and density take into consideration, 0.12% ceramics mixing contents is best.

• Journal of Korean Society on Water Environment
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• 제28권2호
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• pp.277-284
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• 2012

This study developed a new ceramics in which natural zeolite was mixed and calcined with industrial by-product such as converter slag, red mud, and fly ash and evaluated the feasibility of the ceramics for removal of heavy metals in acid wastewater. The removal rate of heavy metal by ceramics increased in the order of ZS (zeolite and slag) > ZR (zeolite and red mud) > ZF (zeolite and fly ash) ceramics. The alkalinity increment and coherence of ceramics were increased in the order of ZS > ZR > ZF ceramics. The mixing ratio of natural zeolite to industrial by-product for maximum removal efficiency of heavy metal was 1:1 for ZS ceramics and 1:3 for ZR and ZF ceramics. The order of removal efficiency of heavy metal was observed to be ZS > ZR > ZF ceramics under the mixing ratio of 1:1 for ZS ceramics and 1:3 for ZR and ZF ceramics. The removal efficiency of heavy metal by ZS ceramics with 1:1 mixing ratio was Al 100%, Cd 54.6%, Cr 99.9%, Cu 98.7%, Fe 99.9%, Mn 42.2%, Ni 59.9%, Pb 99.8%, Zn 87.6%, respectively. In addition, the removal capacity of heavy metal by ZS ceramics was observed to be Al 2.01 mM/g, Cd 0.27 mM/g, Cr 1.02 mM/g, Cu 0.83 mM/g, Fe 0.95 mM/g, Mn 0.41 mM/g, Ni 0.55 mM/g, Pb 0.25 mM/g, Zn 0.70 mM/g, respectively. The comparative evaluation in the light of removal capacity, alkalinity increment, and coherence of ceramics showed the ZS ceramics had higher feasibility as a media than others for removal of heavy metals in acid wastewater.

• Journal of Powder Materials
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• 제28권5호
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• pp.381-388
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• 2021

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 1500℃. The densification behavior and mechanical properties of sintered ceramics, such as hardness and fracture toughness, are examined.

• Journal of the Korean Society of Environmental Restoration Technology
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• 제20권5호
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• pp.59-66
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• 2017

Preeminent water treatment plans are essential to preserve the water quality of aquatic biotopes. Previous studies have not been sufficient to provide cost-effective maintenance method since they focused only on the purification of deteriorated water that requires a continuous supply of clean water. This study proposes an economical method of water quality maintenance using water treatment media block constructed vertically using porous ceramics, zeolite, and river pebble. The water treatment media block does not require a separate purification area because it functions as a purifier within the ecological pond which can maximize the biotope area. To evaluate the performance of the water treatment media block, we longitudinally tracked the change of water quality indicators (pH, TDS, COND, DO, T-P, T-N, COD) suggested by Water Environment Standards, Ministry of Environment, Republic of Korea. We compared the water quality of one control (A: general ecological pond composition method of the laminated structure) and two experimental groups (B: a combination of aquatic plants and a water treatment media block, C: a water treatment media block only). As a result, we confirmed that the water treatment media block is an efficient and economical method to maintaining the water quality of the ecological pond for a long time. The water treatment media block will be a great help in providing a better aquatic biotope space for aquatic insects and fishes living in clear water.

• Journal of Digital Convergence
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• 제19권7호
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• pp.303-312
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• 2021

The Possibility of contemporary ceramics creation through the convergence of materials In modern society, the creation of new values through convergence is emerging as a new trend. Modern potters are also trying to expand a new concept of art by combining various materials with other media. In craft, materials are essential and the most fundamental elements of expression. Therefore, from the viewpoints of various fusions, the significance of the fusion between materials will be explored. Also, focusing on paperclay, which is the most likely to be transformed material, we explore creative possibilities in the process of producing materials and works. Chapter 2 presents the concept and significance of fusion and material properties, and introduce the trend of fusion used in contemporary ceramics as material expression. In Chapters 3 and 4, characteristics and possibilities are examined through paper clay production and presentation based on the structure of the previous analysis. As a result, it is intended to present the direction that modern ceramics should pursue through a fusion phenomenon such as bonding between materials in the future and to explore potential possibilities for development.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• 제9권1호
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• pp.99-111
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• 1999

The purpose of this study was to evaluate crystalline silica contents in airborne respirable dusts from various manufacturing industries and to compare analytical ability of two different methods of quantifying crystalline silica, X-ray diffraction(XRD) and Fourie transform infrared spectroscopy(FTIR). Various manufacturing industries with a history of having pneumoconiosis cases and also known to generate dusts containing crystalline silica were investigated. These industries include: ceramics, brick, concrete, and abrasive material etc. The personal respirable dust samples were collected using l0mm, Dorr-Oliver nylon cyclone equipped with 37mm, $5{\mu}m$ pore size. polyvinylchloride (PVC) filters as collection media. All samples were weighed before and after sampling and were pretreated according to the NIOSH sampling and analytical methods 7500, and 7602 for dust collection and quartz analysis. A total of 48 samples were collected from these industries. Initial analyses of these samples showed log-normal distributions for dust and quartz concentrations. Some results from ceramics and stone exceeded current Korean Occupational Exposure Limits. The average concentrations of personal respirable dust by cyclone were 0.43, 0.24, 0.26, 0.42, 0.53 and $0.29mg/m^3$ in ceramics, stone, concrete, glass, briquets, and others, respectively. A comparison of performance of two analytical methods for quantifying crystalline silica was performed using data from ceramics. The results showed that no significant difference was found between two methods for ceramics. The mean crystalline silica contents determined by XRD were 3.41 % of samples from briquets and 7.18 % from ceramics and were 2.58 % from concrete and 10.33 % from ceramics by FTIR. For crystalline silica analysis, two analytical techniques were highly correlated with $r^2=0.81$ from ceramics. Both cristobalite and tridymite were not detected by XRD and FTIR.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 한국분말야금학회 1998년도 춘계학술대회 및 발표대회 강연 및 발표논문 초록집
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• pp.6-6
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• 1998

In 1957, the first magnetic disk drive compatible with a movable head was introduced as an external file memory device for computer system. Since then, magnetic disks have been improved by increasing the recording density, which has brought about the development of a high performance thin film magnetic head. The thin film magnetic head has a magnetic circuit on a ceramic substrate using IC technology. The physical property of the substrate material is very important because it influences the tribology of head/disk interface and also manufacturing process of the head. $Al_{2}O_{3}$-TiC ceramics, so called ALTIC, is known to be one of the best substrate materials which satisfies this property requirement. Even though the head is not in direct contact with the disk, frequent instantaneous contacts are unavoidable due to its high rotating speed and the close gap between them. This may cause damage in the magnetic recording media and, thus, it is very important that the magnetic head has a good wear resistance. $Al_{2}O_{3}$-TiC ceramics has an excellent tribological property in head/disk interface. Manufacturing process of thin film head is similar to that of IC, which requires extremely smooth and flat surface of the substrate. The substrate must be readily sliced into the heads without chipping. $Al_{2}O_{3}$-TiC ceramics has excellent machineability and mechanical properties. $Al_{2}O_{3}$-TiC ceramics was first developed at Nippon Tungsten Co. as cutting tool materials in 1968, which was further developed to be used as the substrate materials for thin film head in collaboration with Sumitomo Special Metals Co., Ltd. in 1981. Today, we supply more than 60% of the substrates for thin film head market in the world. In this paper, we would like to present the sintering process of $Al_{2}O_{3}$-TiC ceramics and its property in detail.

• Journal of the Korean Ceramic Society
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• 제48권5호
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• pp.471-478
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• 2011

Investigations of crystal structure and phase transition of $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramics doped with A-site substitution impurity (La, Nd) or B-site substitution impurity (Sb, Nb) at 2 mol% concentration were carried out. X-ray diffraction patterns of impurities doped $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramics have been measured at pressures up to ~5 GPa with diamond anvil cell and synchrotron radiation. The patterns were obtained at room temperature using methanol-ethanol mixture as pressure-transmitting media. In order to refine the crystal structure, Rietveld analysis has been performed. The structures of impurities doped $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramics are tetragonal in space group P4mm at ambient pressure and are transformed into a cubic phase in space group Pm$\bar{3}$m as the pressure increases. In this study, when A-site substitution donor $La^{3+}$ or $Nd^{3+}$ ion was added to $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramics, the phase transition phenomena showed up at the pressure of 2.5~4.6 GPa, but when B-site substitution donor $Nb^{5+}$ or $Sb^{5+}$ ion was added to it, the phase transition appeared at relatively lower pressure of 1.7~2.6 GPa.