• Title/Summary/Keyword: Noble Metal

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A Study on the Material of Furniture in Goryeo (고려시대 가구재료 연구)

  • Cho, Sook-Kyung
    • Journal of the Korea Furniture Society
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    • v.25 no.1
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    • pp.19-27
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    • 2014
  • This paper studied the materials of the furniture which the noble men used in Goryeo, based on the furniture material category of solid wood furniture, lacquerware inlaid with mother-of-pearl and hardware. As for the solid wood furniture, the wood and furniture types are inferred based on the documents. The trees used for the wood furniture were zelkova, korean willow, pine, royal paulownia, maidenhair tree, korean pine, chinese juniper and elm. The furniture types were table, chair, wooden bench, small portable table, writing table, and folding screen. As to the types of lacquerware inlaid with mother-of-pearl, most of them were hams with top, which were made of abalone shells. The features of the lacquerware inlaid with mother-of-pearl were in detail and elaborate like the pattern of the full bloomed chrysanthemum. Writing tables were also made of lacquerware as pieces of furniture. Distinctively, the mother-of-pearl furniture material was popular enough to be used even in a horse saddle. Regarding the metal feldspar used as both a practical use and decoration, there are drop handle, hinge, the front basis, and lock seen in the artifacts, which were made of cast iron, bronze, and brass. Their manufacture techniques were eojamoon, bratticing and sheet metal. Through this study of the furniture materials used in Goryeo, it seems that Goryeo furniture focused on the functions rather than on the decorations, and in turn the forms were simple and basic. The technique of mother-of-pearl, a bit elaborate one, was used in the props furniture like kitchen wares, hams, or writing talbes. Probably, the solid wood is inferred to be used in a low wooden bench, a chair, and a table based on the documents.

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Study on the Cathodic Protection Characteristics of Hot Water Boiler by Mg-Alloy Galvanic Anode(1) (Mg 합금 유전양극에 의한 온수Boiler의 음극방식특성에 관한 연구(1))

  • 임우조;윤병두
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.37 no.2
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    • pp.147-152
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    • 2001
  • Corrosion damage of boiler, factory equipment and so forth occur quickly due to using of the polluted water, resulting in increasing leak accident. Especially, working life of hot water boiler using the polluted water becomes more short, and energy loss increases. The cathodic protection method is the most economical and reliable one to prevent corrosion damage of steel structures. Mg-base alloys galvanic anode protection of cathodic protection methode is suitable for the application of hot water boiler using water with high specific resistance such as tap water. This paper is studied on the cathodic protection characteristics of hot water boiler. In tap water solution, the measurement of cathodic protection potential according to the time elapsed is carried out, and behavior of cathodic polarization with current change is investigated. The main results obtained are as follows. In hot water boiler shell, the open circuit potential of base metal become less noble than that of weld Bone, and the current density of base metal becomes low than that of weld zone. The further distance from Mg-alloy galvanic anode, the higher cathodic protection potential of hot water boiler appears. And protective potential becomes high according to pass cathodic protection time and after 6∼10 days become stable.

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Biomimetic Copper Complex Containing Polymer Modified Electrode for Electrocatalytic Reduction of Oxygen

  • Saravanakumar, D.;Nagarale, Rajaram Krishna;Jirimali, Harish Chandra;Lee, Jong Myung;Song, Jieun;Lee, Junghyun;Shin, Woonsup
    • Journal of Electrochemical Science and Technology
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    • v.7 no.4
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    • pp.298-305
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    • 2016
  • The development of non-precious metal based electrocatalysts is highly desired for the oxygen reduction reaction (ORR) as alternates to noble metal based ORR electrocatalysts. Herein, we report mononulcear copper(II) complex $[CuLbpy]ClO_4$ (L=4-[(2-hydroxyphenylimino)methyl]benzoic acid) containing poly(allylamine.HCl) polymer (PAlACuLbpy) as an electrocatalyst for oxygen reduction reaction (ORR). PAlACuLbpy was mixed with poly(acrylic acid) and tetraethylortho silicate to prepare a composite and then deposited on the screen printed electrode surface. The modified electrode (PAlACuLbpy/PCE) is highly stable and showed a quasi-reversible redox behavior with $E_{1/2}=-0.2V$ vs. Ag/AgCl(3 M KCl) in 0.1 M phosphate buffer at pH 7 under argon atmosphere. PAlACuLbpy/PCE exhibited a remarkable ORR activity with an onset potential of -0.1 V vs Ag/AgCl in 0.1 M PB (pH 7) in the presence of oxygen. The kinetics for ORR was studied by rotating disk voltammetry in neutral aqueous medium and the results indicated that the number of electrons involving in the ORR is four and the conversion products are water and hydrogen peroxide.

Study of the Correlation of Plasma Resonance and the Refractive Index to Dielectric Dispersion in the Complex Plane

  • Zhou, Xiao-Yong;Shen, Yan;Hu, Er-Tao;Chen, Jian-Bo;Zhao, Yuan;Sheng, Ming-Yu;Li, Jing;Zheng, Yu-Xiang;Zhao, Hai-Bin;Chen, Liang-Yao;Li, Wei;Jiang, Xun-Ya;Lee, Young-Pak;Lynch, David W.
    • Journal of the Optical Society of Korea
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    • v.17 no.1
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    • pp.27-32
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    • 2013
  • Based on the dispersive feature of the dielectric function of noble metals and the wave vector conservation in physics, both the plasma effect and the complex refractive index, which are profoundly correlated to the complex dielectric function and permeability, have been studied and analyzed. The condition to induce a bulk or a surface plasma in the visible region will not be satisfied, and there will be one solution for the real and the imaginary parts of the refractive index, restricting it only to region I of the complex plane. The results given in this work will aid in understanding the properties of light transmission at the metal/dielectric interface as characterized by the law of refraction in nature.

The Reduction Properties of Nitrate in Water with Palladium and Indium on Aluminum Pillared Montmorillonite Catalyst (팔라디움과 인디움을 담지한 Al 층간가교 몬모릴로나이트 촉매의 수중 질산성질소 환원 특성)

  • Jeong, Sangjo
    • Journal of Korean Society on Water Environment
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    • v.34 no.6
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    • pp.621-631
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    • 2018
  • In this study, catalyst was made through incipient wetness method using palladium (Pd) as noble metal, indium (In) as secondary metal, and montmorillonite (MK10) and Al pillared montmorillonite (Al-MK10) as supporters. The nitrate reduction rate of the catalysts was measured by batch experiments where H2 gas was used as reducing agent and formic acid as pH controller. Transmission electron microscopy (TEM) equipped with energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were all used to determine the elemental distribution of Pd, In, Al, and Si on catalysts. It was observed that Al pillaring increased the Al/Si elemental composition ratio and point of zero charge of MK10, but decreased its BET specific surface area and pore volume. The nitrate reduction rate of Al-MK10 Pd/In was 2.0 ~ 2.5 times higher than that of MK10 Pd/In using artificial groundwater (GW) in ambient temperature and pressure. Nitrate reduction rates in GW were 1.2 ~ 1.7 times lower than those in distilled deionized water (DDW). Nitrate reduction rates in acidic conditions were higher than those in neutral condition in both GW and DDW. The amount of produced NH3-N over degraded NO3- at acid conditions was lower than that of neutral condition. Even though the leaching of Pd after reaction was measured in DDW it was not detected when both Al-MK10 Pd/In and MK10 Pd/In were used in GW. The modification of montmorillonite as a supporter significantly increased the reductive catalytic activities of nitrates. However, the ratio of producing ammonia by-products to degraded nitrates in ambient temperature and pressure was similar.

Optimization of the Pt Nanoparticle Size and Calcination Temperature for Enhanced Sensing Performance of Pt-Decorated In2O3 Nanorods

  • Choi, Seung-Bok;Lee, Jae Kyung;Lee, Woo Seok;Ko, Tae Gyung;Lee, Chongmu
    • Journal of the Korean Physical Society
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    • v.73 no.10
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    • pp.1444-1451
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    • 2018
  • The surface-to-volume ratio of one-dimensional (1D) semiconductor metal-oxide sensors is an important factor for achieving good gas sensing properties because it offers a wide response area. To exploit this effect, in this study, we determined the optimal calcination temperature to maximize the specific surface area and thereby the sensitivity of the sensor. The $In_2O_3$ nanorods were synthesized by using vapor-liquid-solid growth of $In_2O_3$ powders and were decorated with the Pt nanoparticles by using a sol-gel method. Subsequently, the Pt nanoparticle-decorated $In_2O_3$ nanorods were calcined at different temperatures to determine the optimal calcination temperature. The $NO_2$ gas sensing properties of five different samples (pristine uncalcined $In_2O_3$ nanorods, Pt-decorated uncalcined $In_2O_3$ nanorods, and Pt-decorated $In_2O_3$ nanorods calcined at 400, 600, and $800^{\circ}C$) were determined and compared. The Pt-decorated $In_2O_3$ nanorods calcined at $600^{\circ}C$ showed the highest surface-to-volume ratio and the strongest response to $NO_2$ gas. Moreover, these nanorods showed the shortest response/recovery times toward $NO_2$. These enhanced sensing properties are attributed to a combination of increased surface-to-volume ratio (achieved through the optimal calcination) and increased electrical/chemical sensitization (provided by the noble-metal decoration).

Preparation of perovskite-based catalysts and fuel injection system for high durability of diesel reforming (디젤 개질을 위한 페로브스카이트 구조 촉매와 연료주입 시스템의 개발)

  • Rhee, Junki;Park, Sangsun;Shul, Yong-Gun
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.11a
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    • pp.115.2-115.2
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    • 2010
  • Autothermal reforming(ATR) processes of hydrocarbon liquids such as diesel fuels are spotlighted as methods to produce hydrogen for Fuel cell. However, the use of heavy hydrocarbons as feedstocks for hydrogen production causes some problems which increase the catalyst deactivation by the carbon deposition. Coking can be inhibited by increasing the water dissociation on the catalyst surface. This results in catastrophic failure of whole system. Performance degradation of diesel autothermal reforming leads to increase of undesirable hydrocarbons at reformed gases and subsequently decrease the performance. In this study, perovskite-based catalysts were investigated as alternatives to substitute the noble metal catalyst for the ATR of diesel. The investigated perovskite structure was based on LaCrO3. and metals were added at the A-site to enhance oxygen ion mobility, transition metals were doped on the B-site to enhance the reformation. Substituted Lanthanum chromium perovskite were made by aqueous combustion synthesis, which can produce high surface area. And for the homogeneous fuel supply, we made ultrasonic injection system for reforming. We compared durability of evaporation system and ultrasonic system for fuel injection.

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The Synthesis of Copper Nanowire with high aspect ratio by capping agent for textile electronics

  • Byun, Woonghee;Kim, Minho;Kim, Yong-Hoon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.379.1-379.1
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    • 2016
  • Recently, new types of wearable devices such as textile electronics are considered as the next generation wearable electronics. To realize the textile electronics, conductive fibers are required to supply the power and for signal processing. Conventionally, silver nanowires (Ag NWs) have been attracted as one of the conductive additives in the fibers, however, using the Ag NWs may lead to high production cost since it is a noble metal. Many researches have been done to replace the Ag NWs into a cheaper materials such as copper nanowires (Cu NWs). Here, we synthesized ultra-long Cu NWs for a conductive filler material in conductive fibers, taking advantages of their structural features. To investigate the effect of capping agents on the aspect ratio of the synthesized Cu NWs, we used various capping agents such as hexadecylamine, butylamine, ethylenedilamine and oleylamine in the Cu NW synthesis. In this research, the effects of capping agents on the structure and the synthesis of Cu NWs are presented.

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Development of Catalytic Combustion Boiler in Domestic Use (가정용 촉매연소 보일러 개발)

  • Kim, Ho-Yeon;Lee, Seung-Ho;Cho, Won-Ihl;Baek, Young-Soon
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.677-682
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    • 2001
  • Catalytic combustion is the environmental-friendly technology, which has been applied to a variety of areas for industrial and domestic use in recent years. Accordingly, this study performed the development of the catalytic manufacturing technology for the high temperature and of the catalytic combustor in priority, which were aimed to be applied to a commercialized boiler. Paliadium(Pd) of a noble metal was used as a catalyst for the high temperature and supported on alumina($Al_[2}O_{3}$) and zirconia($ZrO_{2}$) in constant weight ratio. Activity of Pd catalysts is compared and analyzed in the catalytic combustion of natural gas. The ratio of $Pd/Al_{2}O_{3}=4$ was found to be better than any other weight ratios in activity and durability. The performance examination of catalysts and of combustion through the plate-type combustor made it possible to be developed the cylindrical-type combustor which has increased combustion area. Catalytic combustion boiler of 25,000 kcal/hr class was also developed, which had the optimum combustion condition at the nozzle of 5.95mm and the orifice of 21mm. This condition was determined through the performance experiments of catalytic combustion boiler to which the cylindrical-type catalytic combustor was applied.

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A study on dietary culture in Nara Dynasty in JAPAN (나양시대(奈良時代)의 식생활(食生活))

  • Lee, Hyo-Gee
    • Journal of the Korean Society of Food Culture
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    • v.12 no.1
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    • pp.11-16
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    • 1997
  • The Nara Dynasty of Japan lasted from 710 to 784 A.D, which corresponds to the period of the Unified Shilla Kingdom of Korea. The Nara Dynasty enacted the 'Daiho Law and Ordinance' by referring to those of Tang Dynasty of China. Under these legal systems, the Ministries were defined, and foods were used for paying taxes or as currency. The characteristics of the dietary culture in Nara Dynasty were as follows. 1) They obtained food from rice and other grain farming, hunting and fishery. Rice was their main staple and was also used for preparing porridge and brewing wine. 2) Under the influence of Buddhism, meat was prohibited, and milks or dairy products were supplemented for improving malnutritional status. 3) They also used seasonings, spices and sweeteners to enhance the taste and produced medicines by extracting plants, animals and minerals. 4) While chopsticks were made of bamboo, willow, silver, shell, tree or bronze, such utensils as pan earthenware steamer, or charcoal pots were used for preparing meals. 5) Highly qualified utensils, made of porcelains painted with lacguetr, metal, glass, horn and stone, were produced as handcraft art wad developed. 6) Chinese style cousines and cooking methods were popular and various types of preserving techniques like drying or salting were used. Processed cookies were also developed. 7) Although flour was used mainly among noble class people, ordinary people also used it. The royal families ate milk products a lot and even fried foods. 8) One can say that Buddism exerted an influence on Vegetarianism from this era.

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