• 제목/요약/키워드: Material chemistry

검색결과 2,190건 처리시간 0.488초

Interrelation between Two-Dimensional Direct and Reciprocal Lattices (2차원적(次元的)인 직격자(直格子)와 역격자간(逆格子間)의 상호관계(相互關係))

  • Kim, Young-Sang;Ko, Jae-Jung;Kang, Sang-Ook;Han, Won-Sik;Suh, Il-Hwan;Kim, Jin-Gyu;Kim, Youn-Joong
    • Korean Journal of Crystallography
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    • 제17권1호
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    • pp.1-5
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    • 2006
  • After the definition of the basis vectors of the two-dimensional direct and reciprocal lattices, various interrelations between them are derived, and additionally how to calculate $\vec{d^*}(hk)//direction\;of\;(hk),\;d(hk)=1/d^*(hk),\;[uv]$, planes belonging to a direction [uv], areas and interplanar spacing of 2-dimensional low different lattices are shown.

Radical Additions of Arenethiols to Ynamides for the Selective Synthesis of N-[(Z)-2-(Arylsulfanyl)-1-alkenyl]amides

  • Sato, Akinori;Yorimitsu, Hideki;Oshima, Koichiro
    • Bulletin of the Korean Chemical Society
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    • 제31권3호
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    • pp.570-576
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    • 2010
  • A variety of ynamides undergo highly regio- and stereoselective radical addition of arenethiols with the aid of triethylborane as a radical initiator. The products, N-[(Z)-2-arylsulfanyl-1-alkenyl]amides, can be reduced with triethylsilane in trifluoroacetic acid to yield N-[2-(arylsulfanyl)alkyl]amides.

Isolation, structure elucidation and physicochemical properties of novel antibiotic polypeptide, $\varepsilon-(L-\beta-Iysine)$ polypeptide from Streptomyces sp. DWGS2

  • Donghyuk Shin;Kim, Daesung;Lee, Deoggeun;Lee, Hyeongkyu;Hoshik Won
    • Journal of the Korean Magnetic Resonance Society
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    • 제6권1호
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    • pp.69-77
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    • 2002
  • During the screening of material which has the antimicrobial activity against aminoglycoside-resistant bacteria, A new material $\varepsilon$-(L-$\beta$-Iysine) polypeptide from a culture medium of Streptomyces sp.(DWGS2) was isolated, and the structure and the physicochemical properties of the new material were elucidated. The new material was separated by column chromatography of the culture medium using Dowex1$\times$2, Silica gel, and Sephadex LH20 etc. The chemical structure and molecular weight were determined with the data of various NMR experiments, MALDI mass, and ESI mass experiments. The antimicrobial activity of $\varepsilon$-(L-$\beta$-Iysine) polypeptide is not only better than equal to the activity of known aminoglycoside type of antibiotics(MIC=3.125 - 6.25ug/mL) but also effective against aminoglycoside-resistant bacteria and fungi. If the mechanism of antimicrobial activity against aminoglycoside- resistant bacteria is figured out, the $\varepsilon$-(L-$\beta$-Iysine) polypeptide can be utilized for the treatment of diseases caused by aminoglycoside-resistant bacteria.

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Development of a Nutritional Supplement Certified Reference Material for Elemental Analysis

  • Lee, Jong Wha;Heo, Sung Woo;Kim, Hwijin;Lim, Youngran;Lee, Kyoung-Seok;Yim, Yong-Hyeon
    • Mass Spectrometry Letters
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    • 제9권4호
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    • pp.105-109
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    • 2018
  • A certified reference material (CRM) for the analysis of inorganic nutrients in nutritional supplements has been developed. Accurate mass fractions of chromium (Cr), iron (Fe), copper (Cu), and zinc (Zn) were determined by isotope dilution inductively coupled plasma mass spectrometry (ID ICP/MS). The measurement results were used to assign certified values for the CRM, which were metrologically traceable to the definitions of the measurement units in the International System of Units (SI). Production of a candidate reference material (RM) and the certification processes are summarized. Each nutrient in the CRM showed good homogeneity, which was estimated using relative standard deviations of the measurement results of twelve bottles in a batch. This CRM is expected to be an important reference to improve reliability and comparability of nutrient analyses in nutritional supplements and related samples in analytical laboratories.

Novel Organic Sensitizers with a Quinoline Unit for Efficient Dye-sensitized Solar Cells

  • Choi, Hye-Ju;Choi, Hyun-Bong;Paek, Sang-Hyun;Song, Ki-Hyung;Kang, Moon-Sung;Ko, Jae-Jung
    • Bulletin of the Korean Chemical Society
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    • 제31권1호
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    • pp.125-132
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    • 2010
  • Three organic sensitizers, JK-128, JK-129, and JK-130 containing quinoline unit are designed and synthesized. Under standard global AM 1.5 solar condition, the JK-130 sensitized solar cell gave a short circuit photocurrent density of 11.52 mA $cm^{-2}$, an open circuit voltage of 0.70 V, and a fill factor of 0.75, corresponding to an overall conversion efficiency of 6.07%. We found that the $\eta$ of JK-130 was higher than those of other two cells due to the higher photocurrent. The higher $J_{sc}$ value is attributed to the broad and intense absorption spectrum of JK-130.