摘要 :
The energies of combustion of single-walled and multi-walled carbon nanotubes were measured by using an isoperibolic micro-combustion calorimeter. The values of the massic energy of combustion in oxygen at T = 298.15 K and pAA = 0...
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The energies of combustion of single-walled and multi-walled carbon nanotubes were measured by using an isoperibolic micro-combustion calorimeter. The values of the massic energy of combustion in oxygen at T = 298.15 K and pAA = 0.1 MPa of the compounds under study were obtained as: (- 27,635.0 +/- 9.5) and (- 32,347.3 +/- 15.3) J g(-1), respectively. The corresponding standard molar enthalpies of formation were derived as: (4.7 +/- 1.3) and (0.8 +/- 0.9) kJ mol(-1), respectively. The used calorimeter to test the compounds was calibrated previously with benzoic acid NIST 39j, salicylic acid and 1,2,4-triazole.
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To obtain reliable standard energies of combustion with small amounts of C, H, O compounds, a new microcombustion calorimetry system has been set up. The design, construction, calibration and measurement experiments are described....
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To obtain reliable standard energies of combustion with small amounts of C, H, O compounds, a new microcombustion calorimetry system has been set up. The design, construction, calibration and measurement experiments are described. The system includes a commercial combustion bomb with an internal volume of 22 cm{sup}3. Samples of around 80 mg are suitable if one wants to retain the same levels of accuracy and reproducibility as those in macrocombustion experiments. Calibration of the calorimeter was performed using benzoic acid. ε(calorimeter)=2083.74 ± 0.48 J K{sup}(-1) was obtained. Combustion measurements using m-methoxybenzoic acid were made in order to verify the chemistry of the combustion process involved in the corresponding analysis of results and the accuracy of the measurement of combustion energy. The uncertainty of the results shows that the instrument described and the experimental procedure used for the determination of enthalpies of formation of compounds containing C, H and O provide a high reliability.
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An isoperibolic combustion calorimeter developed to measure the enthalpy of combustion of organic compounds containing carbon, hydrogen, oxygen, and nitrogen atoms has been assembled, calibrated, and tested. The calorimeter was ca...
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An isoperibolic combustion calorimeter developed to measure the enthalpy of combustion of organic compounds containing carbon, hydrogen, oxygen, and nitrogen atoms has been assembled, calibrated, and tested. The calorimeter was calibrated with benzoic acid NIST 39j, and the resulting energy equivalent was epsilon(calor) = (10116.8 +/- 0.5) J K-1. Salicylic acid, 1,2,4-triazole, and acetanilide were used as test compounds. The main result is that all obtained values of the standard molar enthalpy of formation for the test compound are in agreement with the results available in the literature.
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This is not a comprehensive review on the topic of single walled carbon nanotubes (SWCNTs). Because it is very broad - a simple search on ‘carbon nanotubes’ provides well over a million citations - we are focusing on a brand of ...
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This is not a comprehensive review on the topic of single walled carbon nanotubes (SWCNTs). Because it is very broad - a simple search on ‘carbon nanotubes’ provides well over a million citations - we are focusing on a brand of SWCNTs produced by our company, OCSiAl, trademarked as TUBALL? or just Tuball. It is a well-known product on the market and there is a good citation record on the applications of Tuball in industry and research labs, see Fig. 1. Despite this, there is no published data in the literature properly referencing its quality and the examples of its applications are often left without sufficient characterization. Because of that, we feel that it is well overdue to have a proper summary accessible to many researchers. Besides, the beneficial properties of SWCNT augments in many applications very strongly depend on the quality of SWCNTs and the methods of their introduction into materials. We have a few successful demonstrations here, some of which have not been published yet, and a plenty of additional published results with Tuball nanotubes are included as well.
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Optimal conditions for investigations of thermodynamic properties have been determined experimentally by the method of combustion calorimetry for compounds of the o-benzoquinone series. In the present work, the energies of combust...
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Optimal conditions for investigations of thermodynamic properties have been determined experimentally by the method of combustion calorimetry for compounds of the o-benzoquinone series. In the present work, the energies of combustion in oxygen were measured at T = 298.15 K by static bomb combustion calorimetry for 3,5-di-tert-butyl-o-benzoquinone and 3,6-di-tert-butyl-o-benzoquinone. The experimental values have been used to calculate the standard (p degrees = 0.1 MPa) molar enthalpy of combustion Delta H-c(m)degrees and formation Delta H-f(m)degrees for the examined compounds in the crystalline phase. (C) 2015 Elsevier Ltd. All rights reserved.
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A simple linear relationship between the functionalization reaction energies for the exohedral monovalent addition on the surface of an ideal, infinitely long, single-walled carbon nanotube (SWCNT) and the reciprocal SWCNT radius ...
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A simple linear relationship between the functionalization reaction energies for the exohedral monovalent addition on the surface of an ideal, infinitely long, single-walled carbon nanotube (SWCNT) and the reciprocal SWCNT radius has been derived employing the hard- soft acid basis principle and the tight binding model. The slope of the derived linear relationship is a function of the effective number of valence electrons involved in the functionalization reaction. The intercept of the derived linear relationship, equal to the reaction energies on a planar graphite surface, is a function of the electrophilicity of the monovalent addend and of the condensed Fukui function of its reacting atom. The theoretical predictions of this simple formula are coherent with the computational density functional theory data reported in the literature.
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摘要 :
A simple linear relationship between the functionalization reaction energies for the exohedral monovalent addition on the surface of an ideal, infinitely long, single-walled carbon nanotube (SWCNT) and the reciprocal SWCNT radius ...
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A simple linear relationship between the functionalization reaction energies for the exohedral monovalent addition on the surface of an ideal, infinitely long, single-walled carbon nanotube (SWCNT) and the reciprocal SWCNT radius has been derived employing the hard–soft acid basis principle and the tight binding model. The slope of the derived linear relationship is a function of the effective number of valence electrons involved in the functionalization reaction. The intercept of the derived linear relationship, equal to the reaction energies on a planar graphite surface, is a function of the electrophilicity of the monovalent addend and of the condensed Fukui function of its reacting atom. The theoretical predictions of this simple formula are coherent with the computational density functional theory data reported in the literature.
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An isoperibolic micro-combustion calorimeter was designed, built and set up in our laboratory, taking as base a 1107 Parr combustion bomb of 22 cm(3) of volume. Taken into account the geometrical form of the bomb, it was designed ...
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An isoperibolic micro-combustion calorimeter was designed, built and set up in our laboratory, taking as base a 1107 Parr combustion bomb of 22 cm(3) of volume. Taken into account the geometrical form of the bomb, it was designed and constructed a vessel and a submarine chamber in brass. All of the pieces of the calorimeter were chromium-plated to reduce heat loss by radiation. The calorimeter was calibrated by using pellets of standard benzoic acid (mass approximate of 40 mg) leading to the energy equivalent of epsilon(calor) = (1283.8 +/- 0.6) J center dot K-1. In order to test the calorimeter, combustion experiments of salicylic acid were performed leading to a value of combustion energy of Delta(c)u degrees = -(21,888.8 +/- 10.9) J center dot g(-1) which agrees with the reported literature values. The combustion of piperonylic acid was carried out as a further test leading to a value of combustion energy of Delta(c)u degrees = -(20,215.9 +/- 10.4) J center dot g(-1) in accordance with the reported literature value. The uncertainty of the calibration and the combustion of salicylic acid and piperonylic acid was 0.05%. (c) 2006 Elsevier Ltd. All rights reserved.
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In order to obtain reliable data of the standard enthalpy of combustion of compounds containing carbon, hydrogen, oxygen, and nitrogen atoms, an isoperibolic micro-combustion calorimeter has been developed from a 22 cm ~3 1109A Pa...
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In order to obtain reliable data of the standard enthalpy of combustion of compounds containing carbon, hydrogen, oxygen, and nitrogen atoms, an isoperibolic micro-combustion calorimeter has been developed from a 22 cm ~3 1109A Parr semi-micro oxygen bomb. The calorimeter was calibrated with standard benzoic acid and the resulting energy equivalent was ε(calor) = (1497.39 ± 0.37) J · K~(-1), which means an uncertainty of 0.027%. Combustion measurements using salicylic acid and 1,2,4-triazole were made in order to verify the accuracy of the device. The values of -Δ_cu° at T = 298.15 K for the compounds were (21877.2 ± 4.6) J · g~(-1), and (19217.7 ± 1.9) J · g~(-1), respectively, in agreement with the literature values.
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The adsorption of the potassium atom onto the surface of (n,0) zigzag nanotube (n = 5-10) and (n,n) armchair nanotubes (n = 3, 5) has been studied by density functional theory. The local density approximation calculation of adsorp...
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The adsorption of the potassium atom onto the surface of (n,0) zigzag nanotube (n = 5-10) and (n,n) armchair nanotubes (n = 3, 5) has been studied by density functional theory. The local density approximation calculation of adsorption energy (E_(ads)) emphasized on the dependency of E_(ads) to the diameter and chirality of the nanotube. E_(ads) decreases when the diameter increases. So the (5,0)-K system has the highest adsorption energy among all structures. Furthermore, a significant change was observed in the electronic properties of potassium-adsorbed single-walled carbon nanotube (SWCNT) and the metallic behavior of the nanotube improved. Therefore, our results showed that such modified SWCNTs can be applied in nanodevices such as transistors.
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