• Title/Summary/Keyword: Noble metal decoration

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Hydrogen Sensing of Graphene-based Chemoresistive Gas Sensor Enabled by Surface Decoration

  • Eom, Tae Hoon;Kim, Taehoon;Jang, Ho Won
    • Journal of Sensor Science and Technology
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    • v.29 no.6
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    • pp.382-387
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    • 2020
  • Hydrogen (H2) is considered as a new clean energy resource for replacing petroleum because it produces only H2O after the combustion process. However, owing to its explosive nature, it is extremely important to detect H2 gas in the ambient atmosphere. This has triggered the development of H2 gas sensors. 2-dimensional (2D) graphene has emerged as one of the most promising candidates for chemical sensors in various industries. In particular, graphene exhibits outstanding potential in chemoresistive gas sensors for the detection of diverse harmful gases and the control of indoor air quality. Graphene-based chemoresistive gas sensors have attracted tremendous attention owing to their promising properties such as room temperature operation, effective gas adsorption, and high flexibility and transparency. Pristine graphene exhibits good sensitivity to NO2 gas at room temperature and relatively low sensitivity to H2 gas. Thus, research to control the selectivity of graphene gas sensors and improve the sensitivity to H2 gas has been performed. Noble metal decoration and metal oxide decoration on the surface of graphene are the most favored approaches for effectively controlling the selectivity of graphene gas sensors. Herein, we introduce several strategies that enhance the sensitivity of graphene gas sensors to H2 gas.

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).

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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A study on Perfume case (향(香) 집에 관한연구)

  • 이선재
    • Journal of the Korean Society of Costume
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    • v.33
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    • pp.117-142
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    • 1997
  • This study is on perfume case that is one of a great number of ornaments which was designed by out ancestors. We had developed the tradition and the history of perfume case bag fan-weight etc. These have the same function as the present perfume. case. There were basket-shaped perfume cases which were the smellest one among the personal girdle ornaments in the silla era. The various patterned perfume case were made of gold metal coral platinum or green jadeite etc. In the single-crop trinkets a embroidered perfume bag with the gold and silver thread whose forms perfectly match their functions appeared during the Yi Dynasty. There was also a perfume bag which was one of the daily necessities. A precious "jul perfume" was carried by noble women. A fan-weight perfume bag was attached to the fan to emphasize the intrinsic beauty of utility and function. It is necessary to know the function of prefume case. As perfume case is weared on the clothes it was given more decorative effects as well as the function of medicinal amulet with a sweet smell. Therefore it is very important for us to study perfume case that has various function as an ornament. So The purpose of this study is to investigate the practical and decorative side of perfume case with the general examines of perfume finding how to practice use through our life. The results were as follows; 1. The first use of perfume is perfume through smoke which is for ceremony of religion It removes human body odor by degrees and spreads a sweet odor. Also the materials for making perfume of early age is aromatic plants which will be used flour-made flowers stems. As the materials for making perfume use is increasing today we can invent alcohol perfume today 2. Our country the custom of perfume-used is wide. Among them men's perfume-used was very special phenomenon. For example men were wearing perfume bag in the Silla era. Because perfume represented wealth and noble in those days. They shew off social position personality through perfume-used. 3. One of early religion ceremony article there was the perfume. And perfume case was means for containing perfume. Gradually the perfume case was used widly as increasing needs of perfume in human life. 4. In the middle period of 'Koryo' Dynasty perfume cases had a close relationship with clothes but after Mongolian has been attacked 'Koryo' there were changes in wearing clothes therefore the position of perfume cases were transfered to coat string that was the origin of decoration style that they began. That is to say the perfume case has been influenced the position of perfume case shapes with changing of fashion. 5. The perfume case has been made manifest various function as an ornament. In the practical side First medical-perfume in perfume case has been played an important role in first-aid medicine in critical condition. Second it was amulet for self protection. That is the shape pattern color materials perfume of the perfume case was represented the amuletive nature. Third it was used as substitute article of perfume. Modern women use liquid-perfume as our ancestors used perfume case bag or jul perfume As started above. Also In the decorative side the perfume case has a beautiful formative arts by itself as well as a close relationship with clothes. That well as a close relationship with clothes. That is when the perfume case is worn on the clothes costume is showed aesthetices. That is the materials shapes color pattern of the perfume case we can see the visual beauty also the materials colors embroidered pattern knots tassel that are used the perfume case are increased the decorative beauty of costume. Sixth the symbol in pattern of the pattern case is shown ancetor's wealth and rank health longevity immortality many-born-boy in those days. Today the perfume case is not used with changing of costume by degrees, Accordingly I hope that the result of this study is an influened in devlopment of the perfume case design with matching the modern fashion.

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