• Title/Summary/Keyword: Silver cluster

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The Electronic Structure of Methanethiol Adsorbed on Silver Surface: An Extended Huckel Study

  • Hwang, Sun-Gu;Jang, Yun-Hee;Kim, Ho-Jing
    • Bulletin of the Korean Chemical Society
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    • v.12 no.6
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    • pp.635-643
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    • 1991
  • The adsorption of methanethiol on a Ag(100) surface has been studied with Extended Huckel calculation in the cluster approximation of the substrate. Since it has been known that methanethiol is chemisorbed dissociatively on silver surface by rupture of S-H bond, the methanethiolate radical is taken as adsorbate. Of the various adsorption sites, the 4-fold hollow site is preferred. The methanethiolate radical is mainly adsorbed via its 2e orbital. The charge transfer from metal to this level leads to the C-S bond weakening, which is consistent with the red shift of C-S stretching mode in surface enhanced Raman (SER) spectrum.

Two Crystal Structures of the Vacuum-Dehydrated Fully $Ag^+$-Exchanged Zeolite X ($Ag^+$ 이온으로 완전히 치환되고 탈수된 두개의 제올라이트 X의 결정구조)

  • Jang, Se Bok;Park, Sang Yun;Song, Seong Hwan;Jeong, Mi Suk;Kim, Yang
    • Journal of the Korean Chemical Society
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    • v.40 no.7
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    • pp.474-482
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    • 1996
  • Two crystal structures of the vacuum dehydrated $Ag^+$-exchanged zeolite X have been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3 at 21(1)$^{\circ}C$ (a=24.922(1)${\AA}$ and a=24.901(1)${\AA}$, respectively). Each crystal was ion exchanged in flowing streams of aqueous $AgNO_3$ for three days. The first crystal was dehydrated at 300$^{\circ}C$ and $2{\times}10^{-6$torr for two days. The second crystal was similarly dehydrated at 350$^{\circ}C$. Their structures were refined to the final error indices, $R_1=0.095\;and\;R_2=0.092$ with 227 reflections, and $R_1=0.096\;and\;R_2=0.087$ with 334 reflections, respectively, for which I > 3${\sigma}$(I). In the first crystal, Ag species are found at five different crystallographic sites: sixteen $Ag^+$ ions fill the site I, the center of the double 6-ring, thirty-two Ag0 atoms fill the I' site in the sodalite cavities opposite double six-rings, seventeen $Ag^+$ ions lie at the 32-fold site II' inside the sodalite cavity at the single six-oxygen ring in the supercage, fifteen Ag+ ions lie at the 32-fold site II, in the supercage, and the remaining twelve $Ag^+$ ions lie at site III' in the supercage at a little off two-fold axes. In the second crystal, all Ag species are located similarly as crystal 1; 16 at site I, 28 at site I', 16 at site II, 16 at site II', 6 at site III and 6 at site III'. Total 88 silver species were found per unit cell. The remaining four Ag atoms were migrated out of the zeolite framework to form small silver crystallites on the surface of the zeolite single crystal. In the first structure, the numbers of Ag atoms per unit cell are approximately 32.0 and these may form tetrahedral $Ag_4$ clusters at the centers of the sodalite cavities. The probable four-atom cluster is stabilized by coordination to two $Ag^+$ ions. The Ag-Ag distance in the cluster, ca. 3.05 ${\AA}$, is a little longer than 2.89 ${\AA}$, Ag-Ag distance in silver metal. At least two six-ring $Ag^+$ ions on sodalite cavity (site II') must necessarily approach this cluster and this cluster may be viewed as a distorted octahedral silver cluster, (Ag6)2+.

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Study on Relationship between Elderly Group Lifestyle and Selection Attributes in the Health Functional Foods (실버층 라이프스타일에 따른 건강기능식품 선택속성에 관한 연구)

  • Lee, Myung Sook;Kim, Sook Eung
    • Korean Journal of Clinical Pharmacy
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    • v.25 no.4
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    • pp.286-295
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    • 2015
  • Objective: This experiment is to study how elderly group and their various lifestyles interact with health functional foods, according to their selection behavior. Different lifestyles will be observed closely, as well as how different health conditions and consumer involvements will affect critical decision making in selecting health functional foods. Method: Theories and discoveries from original advanced research were compared parallel to the new study. Results: First, cluster analysis and exploratory analysis were performed amongst different elder lifestyles. Lifestyle exploratory analysis was used for healthy, unique, leisure, and economical-style elders. Cluster analysis was used for material trend oriented, health oriented, complacent oriented-style elders. Health Functional Foods' selection trait Exploratory Factor Analysis showed that product's originality (function, uniqueness, specialty, compatibility, distributor, expiration date), quality (amount, daily dose, visual representation, accessibility, portability, natural ingredients), and popularity (product container, brand image, taste and smell, advertised product, domestic or import, well-known function) were the three main causes. Secondly, the amount of benefits for the elderly group health lifestyle were affected by 'Interest in health', 'Notability of the health functional food', and 'Functionality approved mark'. Specifically, the importance of, 'Interest in health', 'Notability of health functional food', and 'Functionality approved mark' were noticeably high within health oriented elders. Lastly, after examining the data from elder lifestyle's relationship with health functional food selection trait, all three different results showed equal importance. If you closely examine material trend oriented elderly group, selection trait showed distinctively high regards in 'Fundamental Attribute', 'Typical Attribute', and 'Cognitive Attribute'. Health oriented elders showed their distinctively high regards in 'Natural Attribute', and less consideration in 'Typical Attribute' and 'Cognitive Attribute'. Complacent oriented-style elderly group showed less focus on 'Fundamental Attribute', and even less in 'Typical Attribute', and 'Cognitive Attribute'. Health oriented elderly group concluded with above data from the fact that they showed most importance and involvement in health beneficial products that are scientifically proven. Material trend oriented elderly group showed balanced traits in their concluded data, showing that they prefer function, safety, as well as the brand image and their reputation. Also, they consider the products' outer elements, such as design and product name, in order to sense inner functions. Conclusion: So, Silver Business corporations must develop products to fulfill the market demands, and strategize marketing plans to better target the correct audience.

An Experimental study on the human's physiological in Smart Textile Materials by Using Medical Infrared Thermo graphic Imaging (적외선 체열 영상 진단법을 이용한 스마트 섬유소재와 휴대폰 통화량에 따른 인체 생리반응 연구)

  • Lee Tae-il;Lee Su-jeong;Lee Kyung-mi
    • Journal of the Korean Society of Clothing and Textiles
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    • v.29 no.7 s.144
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    • pp.918-925
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    • 2005
  • The following are the results from the infrared body temperature image test to verify the changes in facial temperature according to call duration with a cellular phone. As for the body temperatures, it appears to be the mean value at the upper central point of phone's battery among 7 different points that are measured, and to be the highest at srernocleido-mastoid and scapular trapezius muscle triangle zone$(34.25^{\circ}C\; and\;34.05^{\circ}C\;each)$. The changes of body temperature according to the time duration shows that the body temperature rises according to the length of phone use because of the heat emitted from the battery. As for the temperature changes according to blocking materials, the one without processing appears to be higher in the mean temperature compared to the others that are processed, NSS(Nano Silver Silk) and NSG(Nano Silver Silk Gold) appear to be the lowest in the temperature to show the best blocking property. As for the temperature changes according to measuring points, it appears to be the highest at P4, P5 with all materials, and one with NSG to be the lowest at Pl, P2, P3, and one with NSS to be the lowest at P3, P4, P5, P6, which is due to the thermal conduction of Au and Ag. And the mean temperature at each point appears to be different according to the materials. Therefore, the study conducted with human participants requires a proper particle size of it which would not penetrate cellular tissues and a proper binder and binding treatment for it, to prevent the physical fatigues and the potential diseases. However, it is highly required for back-up researches to verify various aspects in applying nano silver to textile products.

Effects of Cognitive Age on Consumer Satisfaction and Repurchase Intention by Silvers' Lifestyle in the Hairdressing Shop (미용실에서 실버소비자들의 라이프스타일 유형에 따라 주관적 연령이 소비자만족 및 재구매 의도에 미치는 영향)

  • Kang, Eun-Mi;Park, Eun-Joo
    • Fashion & Textile Research Journal
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    • v.11 no.1
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    • pp.57-65
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    • 2009
  • The purpose of this study was to investigate the effects of cognitive age, service quality, and consumer satisfaction on repurchase intention according to silvers' lifestyle types in the hairdressing shop. Data were obtained from 853 women in the 50's and 60's who living in Busan. Data were analyzed by factor analysis, Cronbach's alpha, cluster analysis and path analysis using SPSS WIN 12.0 and LISREL 8.53. The results of the study were as follows: First. silver consumers were classified by the lifestyle into the Active self-fidelitist, Economy family-oriented, and Passive-stagnant. Service quality of hairdressing shop were consisted of Personal Service, Facilities Service, Skill Service, and Policy Service. Second, according to silvers' lifestyle types, repurchasing intention was differently influenced by cognitive age, perceived store service quality, and consumer satisfaction when hairdressing services. Hairdressers were the most important variable for silver consumers' satisfaction, which influenced the repurchase intention of hairdressing services.

Efficient keV X-ray Generation from Irradiation of in-situ Produced Silver Clusters by Ti:sapphire Laser Pulses

  • Chakravarty, U.;Naik, P.A.;Kumbhare, S.R.;Gupta, P.D.
    • Journal of the Optical Society of Korea
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    • v.13 no.1
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    • pp.80-85
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    • 2009
  • An experimental study of energy absorption and x-ray emission from ultrashort laser pulse irradiation of in-situ produced solid clusters has been performed. Silver clusters produced by a 30 mJ, 300 ps laser pulse were irradiated up to an intensity of $3{\times}10^{17}\;W/cm^2$ by a 70 mJ, 45 fs compressed laser pulse from the same Ti:sapphire laser. Absorption of the laser light exceeding 70% was observed, resulting in an x-ray yield (>1 keV) of ${\sim}60{\mu}J$ pulse. This may constitute a much simpler means of intense x-ray generation using ultrashort laser pulses as compared to the irradiation of structured / pre-deposited cluster targets, and it offers higher x-ray conversion efficiency than that from gas clusters and planar solid targets.

Identification of Fatty Acids in the Oils of Pine Nuts by GC-MS of Their Picolinyl Esters and 4,4-dimethyloxazoline Derivatives in Combination with Silver-Ion Chromatography

  • Kim, Seong-Jin;Woo, Hyo-Kyeng;Seo, Min-Young;Joh, Yong-Goe
    • Journal of the Korean Applied Science and Technology
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    • v.19 no.3
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    • pp.222-244
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    • 2002
  • A mixture of methyl ester derivatives of fatty acids from the oils of pine nuts was well resolved to five fractions differing by degree of unsaturation by silver ion solid-phase extraction column chromatography ($Ag^{+}$-SEC). Polyunsaturated fatty acid with non-methylene interrupted conjugated double bond (NMiDB) radical held more strongly to silver ions in the column than methylene interrupted conjugated double bond (MiDB) one when they had the same number of double bonds. Although both the picolinyl ester and DMOX derivative provided clear mass ion species powerful enough to elucidate the structure of the polyunsaturated fatty acid (PUFA) with NMiDB and/or methylene interrupted conjugated double bond (MiDB) radical in the oils, the picolinyl ester of PUFA with NMiDB radical did not provide a cluster of mass ions neighboring diagnostic mass ions induced by the double bond in the proximal to the carboxyl group. However, the DMOX derivative of PUFA with NMiDB group as well as MiDB showed abundant mass ion species differing by gaps of 12 amu, which made it possible with greater ease to locate the double bonds in the molecule. The oil contained $C_{18:2{\omega}6}$ (46.2 %) and $C_{18:1{\omega}9}$ (25.4 %) as main components, and considerable amounts of PUFAs with NMiDB radical such as ${\Delta}^{5.\;9.\;12}-C_{18:3}$ (16.0 %), ${\Delta}^{5.\;9}-C_{18:2}$ (2.3 %) and ${\Delta}^{5.\;11.\;14}-C_{20:3}$ (0.8 %).

Properties of Porous Silver with Polysiloxane Addition (다공성 은의 폴리실록센 첨가에 따른 물성 변화)

  • Kim, Eun-seok;Kim, Ik-gyu;Kim, Kwangbae;Song, Ohsung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.8
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    • pp.603-611
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    • 2020
  • A porous material which can contain liquid perfume was manufactured by adding 1~4 wt% of polysiloxane into a composite containing 20 ㎛ Ag powder and 30 wt% of 53 ㎛ salt, sintering for 60 min at 750℃, and melting salt selectively. The changes in pore, hardness, and microstructure were confirmed according to the polysiloxane content both before and after sintering. The manufactured silver liquid container was formed with open pores both before and after sintering, and the container shrunk by 2~7 % in both perpendicular and parallel directions after sintering. Vickers hardness was increased after sintering and was doubled when 2 wt% of polysiloxane was added. In case of the microstructure, the surface condition of the silver liquid container became darker according to the polysiloxane content, and the pore size was decreased from 50 ㎛ to under 10 ㎛. The composition distribution result revealed an even distribution when 2 wt% of polysiloxane was added but uneven distribution when over 3 wt% of polysiloxane was added due to decreased hardness by cluster. Therefore, the addition of an appropriate amount of 2 wt% polysiloxane reinforced the porous silver with open pores to offer application for jewelry usage.