• Title/Summary/Keyword: Silver cluster

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Influence of Sample Preparation Method and Silver Salt Types on MALDI-TOFMS Analysis of Polybutadiene

  • Choi, Sung-Seen;Ha, Sung-Ho
    • Macromolecular Research
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    • v.16 no.2
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    • pp.108-112
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    • 2008
  • Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis of nonpolar polymeric materials is affected by the sample preparation as well as the matrix and cationizing agent. This study examined the influence of silver salt types on the MALDI analysis of polybutadiene (PB). Silver trifluoroacetate (AgTFA), silver benzoate (AgBz), silver nitrate ($AgNO_3$), and silver p-toluenesulfonate (AgTS) were used as the silver salts to compare the MALDI mass spectra of PB. The mixture solution of PB and 2,5-dihydroxybenzoic acid (DHB), as a matrix dissolved in THF, was spotted on the sample plate and dried. A droplet of the aqueous silver salt solution was placed onto the mixture. The mass spectrum with AgBz showed the clear $[M+Ag]^+$ ion distribution of PB while the mass spectrum with AgTFA did not show $[M+Ag]^+$ ions but only silver cluster ions. The mass spectra with $AgNO_3$ and AgTS did not show a clear $[M+Ag]^+$ ion distribution. The difference in the formation of $[M+Ag]^+$ ions of PB depending on the silver salts was attributed to the silver cation transfer reaction between the silver salt and the matrix (DHB). The mass spectrum showed a clear $[M+Ag]^+$ ion distribution of PB when the conjugate acid of the silver salt was less acidic than the matrix.

Demand for Silver Products Versus Lifestyle Among Elderly Consumers (노인소비자의 라이프스타일 유형에 따른 실버상품 수요에 관한 연구)

  • Ahn, Hye-Im;Kim, Hea-Seon
    • Journal of Families and Better Life
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    • v.27 no.2
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    • pp.45-61
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    • 2009
  • The purpose of this study was to develop an understanding of older consumers' lifestyle, and to provide the basic information for developing silver commodities and, in turn, to stimulate the silver industry which has received attention as a next-generation industry. The study divided elderly consumers into four lifestyle categories and analyzed the difference in demographic characteristics among these categories as well as differences in demand for silver products. Data were collected with questionnaire and analyzed with frequency analysis, factor analysis, K-means cluster analysis, one-way ANOVA, and a $x^2$ test using SPSS 15.0. Four different lifestyles categories were identified among elderly consumers : conservative and stability oriented (22 persons, 33.3% of the sample), progressive and relation oriented (22 persons, 15.0%), reality adapted (52 persons, 35.4%), and traditional (24 persons, 16.4%). The demand for silver products demands was significantly different among elderly consumers in the four different lifestyle groups.

A Research on the Service Environment Evaluation Elements for Development of the Silver Town (실버타운 개발을 위한 서비스환경 평가요인에 관한 연구)

  • Ha, Jeung-Soon;Kwak, Jae-Yong
    • Journal of the Korean housing association
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    • v.18 no.5
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    • pp.143-150
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    • 2007
  • The purpose of this research is to example the general trend of the service environment evaluation of the silver town and classify based on the service environment evaluation to suggest a effective method and alternatives fur development companies. The survey population of this study focused on 40s and 50s' middle aged both genders living in the Seoul and national capital region, we used random sampling method. The analytical methods used in this study were frequency, mean, standard deviation, factor analysis, Chi-Squae analysis, ANOVA, cluster Analysis, post-hoc estimation (Duncan test), To verify the reliability of each measure, Cronbach's alpha coefficient was used. As a result of classifying the environment evaluation elements, it was classified into 5 groups for the differentiating strategy on each group. The groups are: life support service type, medical and health support service type, cultural support service type, indifference type, and food support service type.

Children's Wear Purchasing Behavior by Retired Women and the Missy Group with a View to their Shopping Orientation (의복쇼핑성향에 따른 집단별 유아동복 구매행동의 세대 간 차이 -뉴실버세대와 신세대 주부를 중심으로-)

  • Chung, You-Jin;Hwang, Choon-Sup
    • Journal of the Korean Society of Clothing and Textiles
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    • v.36 no.1
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    • pp.84-98
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    • 2012
  • This study examines the children's wear purchasing behavior of younger generation women (the missy group) and in the new-silver generation (retired). The data collected in the study were examined with a view to establish effective marketing strategies within the children's wear market, a market where the age and characteristics of the actual purchasers of the products have become more diverse. A descriptive survey method using a self-administered questionnaire was employed. The sample consisted of 398 females between the ages of 28 and 64 residing in Seoul and the Gyeonggi-do area. Data collected were analyzed by frequency, t-test, ANOVA, factor analysis, cluster analysis, and Cronbach's alpha coefficients. Respondents were classified into 4 groups by their clothes shopping orientation: conformable/brand conscious purchasing type, planned purchasing/enjoy shopping type, store/brand loyal impulse-oriented type, and dependent/low shopping interest type. There were differences between the missy and the new- silver generations under consideration. It is clear from the study that, even though some individuals of the missy group and of new-silver group belonged to the same shopping orientation type, individuals still showed differences with regard to children's wear purchasing behavior.

Crystallographic Evidence for the Reduction of CO in Partially Dehydrated Silver Zeolite A

  • Kim, Yang;Song, Seong-Hwan;Seff, Karl
    • Bulletin of the Korean Chemical Society
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    • v.10 no.3
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    • pp.230-234
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    • 1989
  • The crystal structure of $Ag^+$-exchanged zeolite A vacuum-dehydrated at $370^{\circ}C$ and then treated with carbon monoxide at $$23^{\circ}C$ has been determined by single crystal x-ray diffraction methods in the cubic space group Pm3m at $23^(1){\circ}C$ ; a = 12.116 (2)${\AA}$. The structure was refined to the final error indices $R_1\;=\;0.061\;and\;R_2$(weighted) = 0.068 using 349 independent reflections for which I > 3${\sigma}(I).\;3.6\;Ag_+-CO$ complexes, where -CO may represent -CHO or -$CH_2OH$, were found in each large cavity. By coordination to silver atoms followed by reaction with $Ag^{\circ}and\;H^+$ within the zeolite, carbon monoxide has been partially reduced. In about 28% of the sodalite units, a $Ag_6(Ag^+)_2$ cluster may be present. In about 37% of the sodalite units, three $Ag^+$ ions are found on threefold axes where they may be bridged by three water molecules. The remaining 35% of the sodalite units are empty of silver species. Two $Ag^+$ ions per unit cell are associated with 8-ring oxygens. The remaining ca $$3Ag^+$ ions per unit cell have been reduced during the synthesis and have migrated to form small silver crystallities on the surface of the zeolite single crystal.

Four Crystal Sturctures of Dehydrated Ag$^+$ and Tl$^+$ Exchanged Zeolite A, Ag$_{12-x}Tl_x$-A, x = 2, 3, 4, and 5

  • Kim, Duk-Soo;Song, Seong-Hwans;Kim, Yang
    • Bulletin of the Korean Chemical Society
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    • v.9 no.5
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    • pp.303-308
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    • 1988
  • Four crystal structures of dehydrated Ag(I) and Tl(I) exchanged zeolite A, $Ag_{12-x}Tl_x$-A, x = 2, 3, 4, and 5, have been determined by single-crystal x-ray diffraction techniques. Their structures were solved and refined in the cubic space group Pm3m at $21(1)^{\circ}C$. All crystals were ion exchanged in flowing streams of mixed $AgNO_3\;and\;TlNO_3$ aqueous solution, followed by dehydration at $350^{\circ}C$ and $2{\times}10^{-6}$ Torr for 2 days. In all of these structures, one-sixth of the sodalite units contain octahedral hexasilver clusters at their centers and eight $Ag^+$ ions are found on threefold axes, each nearly at the center of a 6-oxygen ring. The hexasilver cluster is stabilized by coordination to eight $Ag^+$ ions. The Ag-Ag distance in the cluster, ca. 2.92 ${\AA}$, is near the 2.89 ${\AA}$ bond length in silver metal. The remaining five-sixths of the sodalite units are empty of silver species. The first three $Tl^+$ ions per unit cell preferentially associate with 8-oxygen rings, and additional $Tl^+$ ions, if present, are found on threefold axes in the large cavity.

X-ray Absorption Spectra Analysis for the Investigation of the Retardation Mechanism of Iodine Migration by the Silver Ion Added to Bentonite (벤토나이트에 첨가한 은 이온에 의한 아이오딘 이동 저지 메커니즘 규명을 위한 X-선 흡수 스펙트라 분석)

  • Kim, Seung-Soo;Kim, Min-Gue;Baik, Min-Hoon;Choi, Jong-Won
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.8 no.3
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    • pp.201-205
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    • 2010
  • Most of iodine was captured by the block when NaI solution flowed through a bentonite block sorbed silver to retard the migration of iodine released from high-level radioactive wastes. In order to understand in detail the mechanism for the retardation of the iodine by the silver ion, X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) spectra of the silver sorbed bentonite before and after the contact with iodide were compared with those of AgO, $Ag_2O$ and AgI as references. This examination suggests that the silver ion sorbed on the bentonite is desorbed, and then it retards the migration of iodine by forming the cluster of AgI precipitate.