• Title/Summary/Keyword: De-functionalization

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Caffeine as a source for nitrogen doped graphene, and its functionalization with silver nanowires in-situ

  • Ramirez-Gonzalez, Daniel;Cruz-Rivera, Jose de J.;Tiznado, Hugo;Rodriguez, Angel G.;Guillen-Escamilla, Ivan;Zamudio-Ojeda, Adalberto
    • Advances in nano research
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    • v.9 no.1
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    • pp.25-32
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    • 2020
  • In this work, we report the use of caffeine as an alternative source of nitrogen to successfully dope graphene (quaternary 400.6 eV and pyridinic at 398 eV according XPS), as well as the growth of silver nanowires (in-situ) in the surface of nitrogen doped graphene (NG) sheets. We used the improved graphene oxide method (IGO), chemical reduction of graphene oxide (GOx), and impregnation with caffeine as source of nitrogen for doping and subsequently, silver nanowires (NW) grow in the surface by the reduction of silver salts in the presence of NG, achieving a numerous of growth of NW in the graphene sheets. As supporting experimental evidence, the samples were analyzed using conventional characterization techniques: SEM-EDX, XRD, FT-IR, micro RAMAN, TEM, and XPS.

Theoretical Investigation of Edge-modified Zigzag Graphene Nanoribbons by Scandium Metal with Pyridine-like Defects: A Potential Hydrogen Storage Material

  • Mananghaya, Michael
    • Bulletin of the Korean Chemical Society
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    • v.35 no.1
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    • pp.253-256
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    • 2014
  • Functionalization of zigzag graphene nanoribbon (ZGNR) segment containing 120 C atoms with pyridine (3NV-ZGNR) defects was investigated on the basis of density-functional theory (DFT) calculations, results show that edge-modified ZGNRs by Sc can adsorb multiple hydrogen molecules in a quasi-molecular fashion, thereby can be a potential candidate for hydrogen storage. The stability of Sc functionalization is dictated by a strong binding energy, suggesting a reduction of clustering of metal atoms over the metal-decorated ZGNR.

Total Synthesis of a New 7-Deoxyidarubicinone Derivative through the Functionalization of an A-Ring Side Chain

  • Rho, Young S.;Go, Hyeon Gyeong;Kim, Wan Jung;Yu, Dong Jin;Gang, Hyeon Su
    • Bulletin of the Korean Chemical Society
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    • v.21 no.8
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    • pp.774-778
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    • 2000
  • A convenient total synthesis of a new 7-deoxyidarubicinone ivative21,the aglycon of the anticancer anti-biotic idarubicin analogue,is described.Keyfeatures of the synthesis are the Friedel-Crafts acylation and the functionalization of an A-ring si de chain. A synthon 14 for the A and B rings was prepared from intermediate 6 in five steps.

Plant responses to nano and micro structured carbon allotropes: Water imbibition by maize seeds upon exposure to multiwalled carbon nanotubes and activated carbon

  • Dasgupta-Schubert, N.;Tiwari, D.K.;Francis, E. Reyes;Martinez Torres, P.;Villasenor Cendejas, L.M.;Lara Romero, J.;Villasenor Mora, C.
    • Advances in nano research
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    • v.5 no.3
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    • pp.245-251
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    • 2017
  • Multiwalled carbon-nanotubes (MWCNT) and micro-structured carbon, such as biochar or activated carbon (AC), have been seen to significantly increase the growth indices of certain plant species such as maize (Zea mays L.). Seed imbibition is the stage where environmental factors that affect water transport across the seed coat barrier, make a large impact. This work explores the effect on water imbibition by maize seeds when the aqueous environment surrounding the seed is diluted by small concentrations (10 and 20 mg/l) of pristine MWCNT (p-MWCNT), carboxylate functionalized MWCNT (COO-MWCNT) and AC. The degree of sensitivity of the process to (i) large structural changes is seen by utilizing the nano (the MWCNT) and the micro (the AC) allotropic forms of carbon; (ii) to small changes in the purity and morphology of the p-MWCNT by utilizing 95% pure and 99% pure p-MWCNTs of slightly differing morphologies; and (iii) to MWCNT functionalization by using highly pure (97%) COO-MWCNT. Water imbibition was monitored over a 15 hour period by Near Infrared Thermography (NIRT) and also by seed weighing. Seed surface topography was seen by SEM imaging. Analysis of the NIRT images suggests rapid seed surface topological changes with the quantity of water imbibed. While further work is necessary to arrive at a conclusive answer, this work shows that the imbibition phase of the maize seed is sensitive to the presence of MWCNT even to small differences in the purity of the p-MWCNT and to small differences in the physicochemical properties of the medium caused by the hydrophilic COO-MWCNT.

Origami Inspiration in Contemporary Fashion (현대 패션에 나타난 오리가미의 영향)

  • Yim, Eun-Hyuk
    • Journal of the Korean Society of Clothing and Textiles
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    • v.33 no.8
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    • pp.1253-1261
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    • 2009
  • The paper-folding effect of origami signifies a planarization of the body which questions the three dimensional construction of the body in a more conventional clothing system. Un-structured, variable space posited between the body and clothes, and an absence of gender identification characterizes the planarization of the body. Origami inspiration in fashion stresses a will-to-form rather than mere bodily proportion and structure, which explores a trans-extensity that goes beyond the boundary of the body. This study inquires on the influence of origami as a method to create new vestmental space in contemporary fashion. The flat-plane clothes of origami-inspired design are no longer cut to the body and the clothes could be altered by the wearer. The space is introduced in between a three-dimensional dress-body and the body. Origami-inspired design in Japanese avant-garde fashion deconstructs the convention and promotes a symbiosis of body and clothing instead. The shape of the body is completely estranged by three-dimensional sculptures, alluding to the paper folds of origami and the movement of the body that are transmitted to the clothing through fine folding that transform into an unexpected event.