Function Cultivation in Transparent Oxides Utilizing Natural and Artificial Nanostructures

Hosono, Hideo; Hirano, Masahiro

doi:10.1016/b978-008044964-7/50003-0

Cited by 5 publications

(2 citation statements)

References 102 publications

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“…Oxygen radicals O – and O 2 – at extraordinarily high concentration (∼10 20 /cm 3 ) were formed when ceramics were heated in a dry oxygen atmosphere . The total radical concentration reached 1.7 × 10 21 /cm 3 , and the authors attributed this to the absorption of oxygen molecules which react with free oxygen to the radicals as follows in eq : As shown in Figure , we observed a similar phenomenon in which oxygen was adsorbed onto the charcoal surface, forming radicals with a concentration of 7.06 × 10 19 spins/g.…”

Section: Resultssupporting

confidence: 57%

“…7 Oxygen radicals O − and O 2 − at extraordinarily high concentration (∼10 20 /cm 3 ) were formed when ceramics were heated in a dry oxygen atmosphere. 33 The total radical concentration reached 1.7 × 10 21 /cm 3 , and the authors attributed this to the absorption of oxygen molecules which react with free oxygen to the radicals as follows in eq 5: (5)…”

Section: Resultsmentioning

confidence: 99%

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Reactivity and Free Radical Chemistry of Lilac (Syringa vulgaris) Charcoal

2019

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HIGHLIGHTSo Lilac ignites quickly (250-290 o C), and has a narrow combustion temperature range (300-o It is microporous with a surface area of 4.3706m 2 /g, o Lilac has C-C free radicals arising from carbonization, o It forms peroxyl radicals on oxidation in air, o Degassing in N2 and acid washing removes the free radicals. ABSTRACTThe reactivity, porosity and surface chemistry of charcoal determine its combustion behaviour, and these properties depend on the source of the original wood, production conditions and treatment. Here we studied the properties of charcoal derived from lilac (Syringa vulgaris). Its reactivity was tested by isothermal and non-isothermal thermogravimetric analysis and differential scanning calorimetry in air and nitrogen. Its porosity was tested by monitoring nitrogen adsorption at 77 K. The free radical concentration was determined by measuring the electron spin resonance of fresh charcoal, after washing with HCl, and after degassing in air with or without nitrogen. We found that lilac has a specific surface area of 4.3706 m 2 /g and is highly reactive, igniting at 250-300°C with peak combustion at 320-520°C. The quantity of oxygen consumed and heat released during oxidation increased with temperature. The free radical concentration in the fresh charcoal was 5.29 x 10 18 spins/g, compared to 3.49 x 10 19 spins/g after acid washing, 7.06 x 10 19 spins/g after exposure to air, and 3.75 x 10 17 spins/g after degassing with nitrogen before exposure to air. The line width of all the charcoal samples was 11.6-11.9 G. However, degassing the charcoal in nitrogen followed by exposure to air at low temperatures resulted in a four-fold increase in the line width to 41.8 G. The exposure of lilac charcoal to air alone at low temperatures resulted in the formation of persistent peroxyl radicals superimposed on the main peak. The g-values of charcoal samples that were fresh, acid washed, degassed in N2 + air, and degassed in air alone (main peak) were 2.00481, 2.00477, 2.00260 and 2.00483, respectively. The corresponding g-values of the peroxyl radicals superimposed on the main peak were 2.0155, 2.0138, 2.0020 and 2.0007, respectively. The reactivity, free radical content and specific surface area suggest that lilac charcoal is particularly suitable for applications involving energetic materials, catalysis and co-firing.

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Section: Resultssupporting

confidence: 57%

Section: Resultsmentioning

confidence: 99%

Reactivity and Free Radical Chemistry of Lilac (Syringa vulgaris) Charcoal

2019

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Nano‐ and Microsized Cubic Gel Particles from Cyclodextrin Metal–Organic Frameworks

et al. 2012

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The bottom-up control of the three-dimensional shapes of objects in a wide range of sizes, from nanometer to millimeter, has attracted attention in diverse fields. [1,2] For instance, metal nanocrystals having various shapes, such as spherical, cubic, hexagonal plate, and octahedral, have been extensively investigated owing to interest in crystal growth [3] and the control of catalytic activities. [4] Among the inorganic metal oxides and minerals, for example, the crystallization and morphology control of CaCO 3 have been of interest for decades, with relation to biomineralization, to produce the more complex structures that living organisms produce. [5] More recently, sol-gel polymerization using the surface of supramolecular assemblies as templates has been extensively investigated for the fabrication of various well-defined nanoand microsized objects such as mesoporous silica, [6] hollow tubes, [7] and helical ribbon structures. [8] In spite of diverse approaches for controlling the sizes and shapes of inorganic materials in the micro and nanometer ranges, less attention has been paid to organic network polymers, because the network polymers are generally not moldable nor can be processed after formation of the networks as they are insoluble in all solvents and have no observed melting points. As a bottom-up approach, emulsion polymerization using micelles and vesicles as templates produce spherical particles, [9] hollow spherical particles, [10] and a layer structure, [11] whereas the top-down approaches, nanoimprint lithography [12] with photoresist and three-dimensional microfabrication by two-photon laser chemistry, [13] have been reported for controlling the network polymers to form

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