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Littérature scientifique sur le sujet « Radicale CN »

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Publié le 10 mars 2023

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Articles de revues sur le sujet "Radicale CN"

Makiabadi, Batoul, Mohammad Zakarianezhad et Shahin Mohammadzamani. « Theoretical Study of CN Radicals Chemisorption on the Electronic Properties of BC₂N Nanotube ». Journal of Nano Research 48 (juillet 2017) : 38–48. http://dx.doi.org/10.4028/www.scientific.net/jnanor.48.38.

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In this work, we have investigated the adsorption behavior of the CN radicals on electronic properties of BC2N nanotube (BC2NNT) by means of the B3LYP hybrid density functional method using 6-31G(d) basis set. The results show that CN radicals can be chemically adsorbed on the nanotube. Based on the energy analysis, the most stable position of CN radical on the nanotube is C1 site. Also, the C-side complexes are more stable than the N-side complexes. We investigated the effects of CN radicals adsorption on the electronic properties of the BC2N nanotube. According to our calculations, band gap energy of the BC2NNT decreases with increasing the number of CN radicals. It is predicted that the conductivity and reactivity of nanotube increase by increasing the number of CN radicals. Based on the NBO analysis, in all complexes charge transfer occurs from nanotube to CN radical. The AIM results show that, the Xtube…YCN interaction has covalent nature. Generally, The BC2N nanotube can be used to as sensor for nanodevice applications.

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Wang, Degui, Heinz-Peter Schuchmann et Clemens von Sonntag. « Phenylalanine : Its ˙OH and SO4˙⁻-Induced Oxidation and Decarboxylation. A Pulse Radiolysis and Product Analysis Study ». Zeitschrift für Naturforschung B 48, n^o 6 (1 juin 1993) : 761–70. http://dx.doi.org/10.1515/znb-1993-0610.

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Phenylamine has been oxidized by radiolytically generated hydroxyl and sulfate radicals, the ensuing intermediates and their reactions have been studied by pulse radiolysis and product analysis in the absence and presence of oxidants such as Fe(CN)63- and O2. Upon OH radical attack, hydroxycyclohexadienyl-type radicals are mainly formed while Η-abstraction reactions can be neglected. In the presence of Fe(CN)63- these radicals are for the most part oxidized to the corresponding tyrosines (80%), except for the ipso-OH-adduct radicals (≈ 20%). It is concluded that ˙OH-addition is almost random, but with a slight avoidance of the metaposition relative to the ortho-, para- and ipso-positions. Oxygen adds reversibly to the OH-adduct radicals (kf = 1.8 × 108 dm3 mol-1 s-1, kr = 5.4 × 104 s-1). In this case, tyrosine formation occurs by HO2˙-elimination. However, due to side reactions, tyrosine formation only reaches 52% of the OH radical yield. The tyrosine yield drops to 10% in the absence of an oxidant.Upon SO4˙⁻-attack, decarboxylation becomes a major process (33% of SO4˙⁻) alongside the production of tyrosines (43%). Here, with Fe(CN)63- as the oxidant the formation of p-Tyr (18.5%) and m-Tyr (16.5%) is preferred over o-Tyr formation (8.5%). It is believed that in analogy to other systems a radical cation is formed immediately upon SO4˙⁻-attack which either reacts with water under the formation of hydroxycyclohexadienyl-type (“OH-adduct”) radicals, or decarboxylates after intramolecular electron transfer. The radical cation can also arise indirectly through H+-catalysed water elimination from the ˙OH-adduct radicals. At pH 2 and a dose rate of 0.0046 Gy s-1 CO2 formation matches the OH radical yield when ˙OH is the attacking radical. Below pH 2, G(CO2) decreases with falling pH. This indicates the occurrence of another, unimolecular, pathway under these conditions competing effectively with decarboxylation. This appears to be a relatively slow deprotonation reaction of the carboxylprotonated phenylalanine radical cation which gives rise to the benzyl-type radical.

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Hänni, Nora, Kathrin Altwegg, Boris Pestoni, Martin Rubin, Isaac Schroeder, Markus Schuhmann et Susanne Wampfler. « First in situ detection of the CN radical in comets and evidence for a distributed source ». Monthly Notices of the Royal Astronomical Society 498, n^o 2 (3 septembre 2020) : 2239–48. http://dx.doi.org/10.1093/mnras/staa2387.

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ABSTRACT Although the debate regarding the origin of the cyano (CN) radical in comets has been ongoing for many decades, it has yielded no definitive answer to date. CN could previously only be studied remotely, strongly hampering efforts to constrain its origin because of very limited spatial information. Thanks to the European Space Agency's Rosetta spacecraft, which orbited comet 67P/Churyumov–Gerasimenko for 2 yr, we can investigate, for the first time, CN around a comet at high spatial and temporal resolution. On board Rosetta's orbiter module, the high-resolution double-focusing mass spectrometer DFMS, part of the ROSINA instrument suite, analysed the neutral volatiles (including HCN and the CN radical) in the inner coma of the comet throughout that whole 2-yr phase and at variable cometocentric distances. From a thorough analysis of the full-mission data, the abundance of CN radicals in the cometary coma has been derived. Data from a close flyby event in 2015 February indicate a distributed origin for the CN radical in comet 67P/Churyumov–Gerasimenko.

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Cordes, A. Wallace, Charles M. Chamchoumis, Robin G. Hicks, Richard T. Oakley, Kelly M. Young et Robert C. Haddon. « Mono- and difunctional furan-based 1,2,3,5-dithiadiazolyl radicals ; preparation and solid state structures of 2,5-[(S2N2C)OC4H2(CN2S2)] and 2,5-[(S2N2C)OC4H2(CN)] ». Canadian Journal of Chemistry 70, n^o 3 (1 mars 1992) : 919–25. http://dx.doi.org/10.1139/v92-123.

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The preparation and solid state characterization of the bifunctional radical furan-2,5-bis(1,2,3,5-dithiadiazolyl) 2,5-[(S2N2C)OC4H2(CN2S2)] and the related monofunctional radical 2-cyanofuran-5-(1,2,3,5-dithiadiazolyl) 2,5-[(S2N2C)OC4H2(CN)] are described. The crystal structure of 2,5-[(S2N2C)OC4H2(CN2S2)] is orthorhombic, space group Pna21, and consists of interleaved arrays of dimers, for which the mean interannular [Formula: see text] contact is 3.137 Å. The crystal structure of the monofunctional radical 2,5-[(S2N2C)OC4H2(CN)] is monoclinic, space group P21/n, and consists of a ribbon-like network of dimers (mean interannular [Formula: see text] interconnected by close head-to-tail [Formula: see text] contacts. The dimer units form stacks parallel to z, with a mean interdimer [Formula: see text] separation of 3.956 Å. The similarities and differences between these two crystal structures and those of related benzene-substituted systems are discussed. Keywords: dithiadiazolyl radicals, furan-based diradicals, cyanofuran-based radicals, radical dimers, crystal structures.

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Xu, Jun, Tengcai Ma, Jialiang Zhang, Xinlu Deng, Wenfang Zhang et Alessio Perrone. « INVESTIGATION ON OPTICAL EMISSION SPECTRA DURING ECR PLASMA ENHANCED MAGNETRON SPUTTERING CARBON NITRIDE FILM DEPOSITION ». International Journal of Modern Physics B 16, n^o 06n07 (20 mars 2002) : 1120–26. http://dx.doi.org/10.1142/s021797920201097x.

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Emission spectra from the ECR plasma enhanced magnetron sputtering discharge used for CNx film deposition were investigated in the wavelength range 350 – 550 nm. The optical emission spectra from both the negative glow discharge zone near the target surface and the plasma zone formed by ECR discharge and magnetron discharge were studied separately. The dominant chemical species in both zone were found to be N2+, N2* , and CN radicals. But the intensity of CN radical in the plasma zone was greater than that in the negative zone, where an emission band of C2 was detected. The dependence of the intensities of CN band on the working gas pressure was investigated, and the formation of CN radicals, which could be vital in the CNx film deposition process, was discussed. It was shown that a possible mechanism could be the reaction of N2+ and N 2 with C 2 in the gas phase.

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Das, Suresh, et Clemens von Sonntag. « The Oxidation of Trimethylamine by OH Radicals in Aqueous Solution, as Studied by Pulse Radiolysis, ESR, and Product Analysis. The Reactions of the Alkylamine Radical Cation, the Aminoalkyl Radical, and the Protonated Aminoalkyl Radical ». Zeitschrift für Naturforschung B 41, n^o 4 (1 avril 1986) : 505–13. http://dx.doi.org/10.1515/znb-1986-0418.

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Hydroxyl radical reactions with trimethylamine in aqueous solution lead to the formation of the aminoalkyl radical (CH3)2NCH2 (A) and its conjugated acid (CH3)2HN+CH2 (AH+) as well as to the alkylamine radical cation (CH3)3N+(N+). These radicals are transform ed into each other by hydrolytic reactions, e.g.[xxx]Radicals AH+ are more acidic (pKa ≈ 3.6) than the radicals N+(pKa ≈ 8.0). Consequently, N+ predom inate over AH+ under quasi equilibrium conditions (e.g. in the presence of phosphate buffer) and are the only species observed by ESR in acid solutions. Reacting with the protonated amine. OH radicals abstract hydrogen at nitrogen and at carbon with comparable ease. Reaction of OH radicals with the free amine may initially also generate N+, beside H-abstraction at carbon. Radicals A’ absorb more strongly at 260 nm (ε = 3390 dm3mol-1cm-1) than the radical cation N+(ε = 950 dm3mol-1cm-1). Radical A' has reducing properties whereas radicals AH+ and N+ have oxidizing properties and hence can be monitored with p-nitroacetophenone (the reducing radicals), and Fe(CN)64- , N ,N'-tetramethyl-p-phenylenediamine and 2,2'-azinobis-(3-ethyl-benzthiazoline- 6-sulphonate) (the oxidizing radicals). These radicals mainly (≥ 85 % ) disproportionate. one of the products being formaldehyde

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Yong, Yoke Keong, Jun Jie Tan, Soek Sin Teh, Siau Hui Mah, Gwendoline Cheng Lian Ee, Hoe Siong Chiong et Zuraini Ahmad. « Clinacanthus nutansExtracts Are Antioxidant with Antiproliferative Effect on Cultured Human Cancer Cell Lines ». Evidence-Based Complementary and Alternative Medicine 2013 (2013) : 1–8. http://dx.doi.org/10.1155/2013/462751.

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Clinacanthus nutansLindau leaves (CN) have been used in traditional medicine but the therapeutic potential has not been explored for cancer prevention and treatment. Current study aimed to evaluate the antioxidant and antiproliferative effects of CN, extracted in chloroform, methanol, and water, on cancer cell lines. Antioxidant properties of CN were evaluated using DPPH, galvinoxyl, nitric oxide, and hydrogen peroxide based radical scavenging assays, whereas the tumoricidal effect was tested on HepG2, IMR32, NCL-H23, SNU-1, Hela, LS-174T, K562, Raji, and IMR32 cancer cells using MTT assay. Our data showed that CN in chloroform extract was a good antioxidant against DPPH and galvinoxyl radicals, but less effective in negating nitric oxide and hydrogen peroxide radicals. Chloroform extract exerted the highest antiproliferative effect on K-562 (91.28±0.03%) and Raji cell lines (88.97±1.07%) at 100 μg/ml and the other five cancer cell lines in a concentration-dependent manner, but not on IMR-32 cells. Fourteen known compounds were identified in chloroform extract, which was analysed by gas chromatography—mass spectra analysis. In conclusion, CN extracts possess antioxidant and antiproliferative properties against cultured cancer cell lines, suggesting an alternate adjunctive regimen for cancer prevention or treatment.

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McNavage, William, William Dailey et Hai-Lung Dai. « The ν1 and ν2 vibrational bands of the OCCN radical detected through time-resolved Fourier transform IR emission spectroscopy ». Canadian Journal of Chemistry 82, n^o 6 (1 juin 2004) : 925–33. http://dx.doi.org/10.1139/v04-041.

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Through monitoring the IR emission from vibrationally excited radicals generated by exothermic photolysis reactions, the CN stretch (ν1) and the CO stretch (ν2) vibrational bands of the cyanooxomethyl radical (OCCN) have been observed for the first time at 2093 cm1 and 1774 cm1, respectively. The OCCN radical was produced through 193 nm photolysis of methyl cyanoformate (NCC(O)OCH3), carbonyl cyanide (NCC(O)CN), and pivaloyl cyanide (NCC(O)C(CH3)3). The IR emission spectra were recorded by using nanosecond time-resolved Fourier transform IR emission spectroscopy. Assignments of the spectral peaks were made based on observed time and pressure dependences of IR emission intensities, ab initio calculations, and two-dimensional cross-spectra correlation analysis. Key words: radical, cyanooxomethyl, OCCN, time-resolved vibrational spectroscopy, FTIR, substituted carbonyl dissociation reactions, two-dimensional cross-spectra correlation analysis

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Mieden, Oliver J., et Clemens von Sonntag. « Peptide Free-Radicals : The Reactions of OH Radicals with Glycine Anhydride and its Methyl Derivatives Sarcosine and Alanine Anhydride. A Pulse Radiolysis and Product Study ». Zeitschrift für Naturforschung B 44, n^o 8 (1 août 1989) : 959–74. http://dx.doi.org/10.1515/znb-1989-0818.

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The reactions of radiolytically generated OH radicals and H atoms with the cyclic dipeptides of glycine, alanine and sarcosine in deoxygenated aqueous solutions and the subsequent reactions of the transient peptide radicals were studied in the absence and presence of K3Fe(CN)6 as oxidant by pulse radiolysis and product analysis.Hydroxyl radicals and H atoms react with glycine anhydride and alanine anhydride by abstracting an H atom bound at C-3; there is no evidence for any other site of attack at these two peptides. The resulting radicals have pKa values of 9.8 and 10.6, respectively.In the absence of an oxidant the radicals decay by second order (2k = 7.0×108 dm3 mol-1 s-1 and 2k = 4.4×108 dm3 mol-1 s-1, resp.), the main fraction (94% of the glycine anhydride-derived radicals, 90% of the alanine anhydride-derived radicals) yielding dehydrodimers (G = 0.58 μmol J-1 and 0.56 µmol J-1 (in monomer units), resp.). A small portion however disproportionates via abstraction of a C-6-bound Η atom followed by isomerization to 2,5-dihydroxypyrazines (pKa values of the parent 2,5-dihydroxypyrazine at about 7.9 and 10.1) and subsequent addition of water to 2,5-diketo-3-hydroxypiperazines, thus indicating that the transfer of a carbon-bound hydrogen atom is prefered to the transfer of a nitrogen-bound hydrogen atom.No disproportionation products but three different dehydrodimers (G = 0.36, 0.18 and 0.04 µmol J-1 (in monomer units)) were found after irradiation of sarcosine anhydride. In this case a dose rate and solute concentration dependence of dehydrodimer formation indicates a radical-solute reaction converting part of the N-methyl radicals (21% of ‘initial’ attack) into the C-3-yl radicals. A rate constant of k = 600 ± 50 dm3 mol-1 s-1 was obtained for this reaction by measuring and computing the dehydrodimer yields as a function of dose rate and solute concentration. Thus the observed transient spectrum accounts only for about 79% of the radicals from the ‘initial’ attack at C-3.The rate of oxidation of the glycine anhydride-derived radicals by Fe(CN)63- reflects the pKa of the transient radical. The rate constant for oxidation of the (protonated) radical derived from glycine anhydride is: k = 1.0x 108 dm3 mol-1, the corresponding radical anion is oxidized with k = 3.1 × 108 dm3 mol-1 s-1. No change with pH was observed in the case of the alanine anhydridederived radicals (k = 7.9x 108 dm3 mol-1 s-1). In contrast to the disproportionation, oxidation by Fe(CN)63- leads to the removal of a proton from the heteroatom, a carbocation being the intermediate. The resulting dehydropiperazines rapidly add water to yield the corresponding 2,5-diketo-3-hydroxypiperazines (G = 0.61 μmol J-1 after oxidation of the glycine anhydride-derived radicals, G = 0.58 µmol J-1 after oxidation of the alanine anhydride-derived radicals). The radicals derived from sarcosine anhydride are readily oxidized with k = 4.0×108 dm3 mol-1 s-1, independent of pH.1H and 13C{1H} NMR-spectroscopic and mass-spectroscopic data of the products are given.

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Liu, Dongping, Ina T. Martin, Jie Zhou et Ellen R. Fisher. « Radical-surface interactions during film deposition : A sticky situation ? » Pure and Applied Chemistry 78, n^o 6 (1 janvier 2006) : 1187–202. http://dx.doi.org/10.1351/pac200678061187.

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Our imaging of radicals interacting with surfaces (IRIS) method was used to investigate radical-surface reactions during low-temperature plasma-enhanced chemical vapor deposition (PECVD) processes. Special emphasis was placed on the analysis of surface reactivities for CH, SiH, CN, NH, NH2, CF2, and SiCl2 radicals during film growth. The effects of plasma parameters, such as radio frequency (rf) power and gas composition, substrate temperature, and substrate bias on radical-surface reactivity were analyzed. Different radicals exhibit different behavior at the surface of a depositing film. Specifically, CH, SiH, and CN are "sticky", with high surface reactivities. In contrast, other species such as NH, CF2, and SiCl2 do not stick to the surface of growing films and, in some cases are actually generated at the surface of the depositing film. Different plasma systems and parameters can have an effect on the stickiness of some of these species. Our IRIS measurements indicate a molecule's surface sticking probability may also be related to the molecule's electronic configuration and stability, with the most reactive species being molecules with a doublet electron configuration. In contrast, the singlet species examined here tend to be generated at the surface during film deposition. Our results also indicate that when a molecule scatters with greater than 100 % probability, it is likely to be strongly affected by energetic ion bombardment of the film surface.

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Thèses sur le sujet "Radicale CN"

Alagappan, Azhagammai. « Studies of collisional energy transfer in the CN radical by frequency-modulated spectroscopy ». Thesis, Heriot-Watt University, 2007. http://hdl.handle.net/10399/62.

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Jamal, Adeel. « Ab Initio Quantum Chemical Studies on Neutral-Radical Reactions of Ethynyl (C2H) and Cyano (CN) with Unsaturated Hydrocarbons ». FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/736.

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An Ab Initio/RRKM study of the reaction mechanism and product branching ratios of neutral-radical ethynyl (C2H) and cyano (CN) radical species with unsaturated hydrocarbons is performed. The reactions studied apply to cold conditions such as planetary atmospheres including Titan, the Interstellar Medium (ISM), icy bodies and molecular clouds. The reactions of C2H and CN additions to gaseous unsaturated hydrocarbons are an active area of study. NASA’s Cassini/Huygens mission found a high concentration of C2H and CN from photolysis of ethyne (C2H2) and hydrogen cyanide (HCN), respectively, in the organic haze layers of the atmosphere of Titan. The reactions involved in the atmospheric chemistry of Titan lead to a vast array of larger, more complex intermediates and products and may also serve as a chemical model of Earth’s primordial atmospheric conditions. The C2H and CN additions are rapid and exothermic, and often occur barrierlessly to various carbon sites of unsaturated hydrocarbons. The reaction mechanism is proposed on the basis of the resulting potential energy surface (PES) that includes all the possible intermediates and transition states that can occur, and all the products that lie on the surface. The B3LYP/6-311g(d,p) level of theory is employed to determine optimized electronic structures, moments of inertia, vibrational frequencies, and zero-point energy. They are followed by single point higher-level CCSD(T)/cc-vtz calculations, including extrapolations to complete basis sets (CBS) of the reactants and products. A microcanonical RRKM study predicts single-collision (zero-pressure limit) rate constants of all reaction paths on the potential energy surface, which is then used to compute the branching ratios of the products that result. These theoretical calculations are conducted either jointly or in parallel to experimental work to elucidate the chemical composition of Titan’s atmosphere, the ISM, and cold celestial bodies.

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Robert, Jean-Claude. « Production de radicaux CN par la réaction C + N₂O : analyse des distributions rovibroniques et spectroscopie de saturation ». Paris 11, 1985. http://www.theses.fr/1985PA112372.

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Cette thèse présente une étude de la dynamique de la réaction C + N₂O → CN + NO réalisée dans des écoulements subsoniques ou supersoniques. Les spectres de chimiluminescence de CN (A² πi ) ont mis en évidence l’importance des couches limites. Leurs analyses ont permis de donner la distribution vibrationnelle dans différentes conditions expérimentales. La fluorescence induite par laser a été utilisée pour déterminer les distributions vibrationnelles et rotationnelles de CN(X² Σ⁺) et pour estimer la pression partielle de radicaux formés dans la réaction. En supposant les niveaux vibrationnels (X² Σ⁺, v’’ ≥ 4) et (A²πi, v’ ≥ 2) thermalisés, nous avons déduit une valeur du branchement électronique de la réaction. Enfin la possibilité de réaliser un laser chimique fonctionnant sur une transition rovibronique de CN a été discutée.

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Faggi, Sara. « HIRES/E-ELT astrobiology science case. Cosmogonic indicators in comets : Targeting a quantum leap using new-generation high-resolution echelle spectrometers ». Doctoral thesis, 2017. http://hdl.handle.net/2158/1076920.

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Tesi di dottorato in Fisica e Astronomia di Sara Faggi. Ricerca svolta nell'ambito dell'astrobiologia, studio del sistema solare e focalizzata su comete. Questo lavoro di dottorato ha avuto come obbiettivo lo sviluppo di un caso scientifico per uno spettrografo di nuova generazione, riguardante l'origine dell'acqua sulla Terra. - Sara Faggi Ph.D. thesis in Physics and Astronomy. This research focused on cometary science related to astrobiology and solar system exploration. The main aim of this project was to develop a science case for a new generation high resolution spectrograph, regarding the origin of oceans water on our Earth..

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Lai, Shih-ying, et 賴世穎. « Optical-optical double resonance spectroscopy of photo-generated CN radicals ». Thesis, 2013. http://ndltd.ncl.edu.tw/handle/77457848336010232606.

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碩士
國立中山大學
化學系研究所
101
The optical-optical double resonance spectroscopic technique was employed to investigate CN photofragments from ICN photodissociation at 266 nm. The electronic spectroscopy (B ← A ← X) of CN radicals was studied in this thesis. The double resonance experiments were executed in a flow cell with 5 mTorr ICN at 298K and the photodissociation light source was generated from the fourth harmonic output of a Nd: YAG laser. The ground state CN radicals were probed by a double resonance excitation scheme and the fluorescence emissions were measured by a photomultiplier detector. Fluorescence signals were registered by a boxcar integrator and the excitation spectra could be obtained in a straightforward fashion. From the experimental results and spectroscopic theories, the rotational constant of A state CN can be determined.

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Pan, Meng-Ching, et 潘孟青. « Computational Study on Decomposition Mechanisms of Cyanomidyl Radical with Doublet and Quartet Configurations, and the RCCN (R = H, F, Cl, Br, CN, NH2, CH3) Substituted Radicals React with NO ». Thesis, 2011. http://ndltd.ncl.edu.tw/handle/42451309249518944746.

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碩士
中國文化大學
應用化學研究所
99
The reaction mechanisms of (1) the decomposition reaction of cyanomidyl radical (HNCN), and (2) the reaction of RCCN (R=H, F, Cl, Br, CN, NH2, and CH3) radicals with the NO have been investigated by the highlevel ab initio molecular orbital method. The species involved have been optimized at the B3LYP/6-311++G (3df,2p) level and their singlepoint energies are refined by the CCSD(T)/aug-cc- PVQZ//B3LYP /6-311+G(3df,2p) method. For the HNCN decomposition reaction system with two different configurations (doublet and quartet states), our calculated results indicate that there exists two and three favorable paths for the formations of CH + N2. For doublet state case, these two paths are HNCN→TS1→IM4→TS4→ IM2→TS8→CH+N2, and HNCN→TS3→ IM1→TS2→IM2→TS8→CH+N2, respectively. For quartet state case, these three paths are R→TS4→IM5→TS5→IM2→TS7→IM3→TS12→ CH+N2, R→TS9→IM4→TS13→IM1→TS11→IM3→TS12→CH+N2, and R→TS4→IM5→TS10→IM1→TS11→ IM3→TS12 →CH+N2, respectively. In addition, employing the Fukui functions and HSAB theory we are able to rationalize the scenario of these calculated outcomes. For the reaction of RCCN (R=H, F, Cl, Br, CN, NH2, and CH3) radicals with the NO system, our calculated results clearly show that if the substituted RCCN are electron donating groups (for R = F, NH2 and CH3 cases), their corresponding barrier heights for transition states will be slightly decreased. The possible explanations for the decreased and/or increased energy barriers of the substituted RCCN are also analyzed in this part.

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Hsu, Hui-Wen, et 許惠雯. « Computational Study of RNCC(R=H,F,C1,Br,CN,NH2,CH3) Radicals Reaction with NO ». Thesis, 2011. http://ndltd.ncl.edu.tw/handle/40993059160012417910.

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碩士
中國文化大學
化學系應用化學碩士班
100
There are two major themes in this thesis. I. Computational Study of RNCC (R =H, F, Cl, Br, CN, NH2, CH3) Radicals Reaction with NO. We carried out a computational approach of radical reactions of NO + RNCC (R = H, F, Cl, Br, CN, NH2, CH3) to study how the substituted group can influence their corresponding energy barriers. The species involved have been optimized at the B3LYP/6-311++G(3df,2p) level. From our previous work of HNCC + NO reaction, our calculated results indicate that the favorable pathways are the formation of RNN + CCO (P6) and RNC + CNO (P12). Our calculated results clearly show that if the substituted RNCC are electron donating groups (for R = NH2 and CH3 cases), their corresponding barrier heights for transition states will be substantially decreased; while the electron withdrawing groups (for R = H, F, Cl, Br, CN cases), their corresponding barrier heights for transition states will be substantially increased. The possible explanations for the decreased and/or increased energy barriers of the substituted RNCC are also analyzed in this article. II. Quantum-Chemical Calculations on Reaction Mechanisms of B with N2O. The boron possesses some specific properties (metalloid non-metal element) and its electronic configuration is ns2np1, it can accept electron from another donor species. Our purpose of this study is to find the possible reactants which may react with NOx to form the stable product such as N2 which is not harmful to our environment. We used the same method with our first part, but their single-point energies are further refined by the CCSD(T)/aug-cc-PVQZ//B3LYP/6-311++G(3df,2p) method. From our calculated results, it is found that the favorable pathways are the formation of N2 + BO (P1) and BN + NO (P2).

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Lin, Tai-Hung, et 林泰宏. « Reaction mechanisms of RCNN（R=F , Cl , Br, CN, NH2 , CH3）radical with NO molecule via density function theory ». Thesis, 2014. http://ndltd.ncl.edu.tw/handle/99644610196675478003.

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碩士
中國文化大學
化學系應用化學碩士班
103
Abstract We calculated the RCNN (R = H, F, CI, Br, CN, NH2, CH3) radical reacted with NO molecule via Gaussian 03 program. All of the reactants, intermediates, transition states and products have also been optimized at B3LYP/6-311++G (3df, 2p) level. In our study, we found three important reaction pathway, Channel A : R  IM1  TS1  IM4  TS4  P1, Channel B : R  IM2  TS2  P2, and Channel C : R  IM3  TS3  P2, respectively. The result shown the major reaction pathways are the Channel A and Channel C. In the Channel A and C, the rate-determining step is the process of the IM4 transferring to TS4 and the process of the IM3 transferring to TS3, respectively. The furthermore, the calculated result also shown the electron donating group could decrease the energy barrier, and the CH3 group is better than others. The electron-withdrawing group would be enhance the energy barriers, and the functional group of fluorine is more strong than others.

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Zhang, Yi Zhong, et 張奕中. « Density functional study on the reaction mechanisms of RCNC(R=H,F,Cl,Br,CN,NH2,CH3) +Radical with NO ». Thesis, 2015. http://ndltd.ncl.edu.tw/handle/f89vrm.

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碩士
中國文化大學
化學系應用化學碩士班
103
The nitric oxide (NO) is a notorious compound for polluting environment. Recent year, removing nitric oxide from the atmosphere becomes a focus of the investigation. In our work, we study the RCNC (R= H, F, CI, Br, CN, NH2, CH3) radical reacted with NO molecule with Gaussian 03 program. The reactants, intermediates, transitions states and products have also been optimized at B3LYP/6-31G* level. We find two important reaction pathway, PATH A: R→ IM1→ TS1→ IM3 → TS2→ IM4→ TS3→ P1 and PATH B: R→ IM2→ P2. Almost of PATH B is endothermal reaction. Therefore, the PATH A is the major reaction pathway. The rate-determining step in PATH A is the process of the IM3 transfer to TS3. Furthermore, the calculated result also shown the electron donating group could decrease the energy barrier, and the CH3 group is better than others. The electron-withdrawing group would be enhance the energy barriers, and the F group is more strong than others.

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Livres sur le sujet "Radicale CN"

Spencer-Smith, Rowland David. Kinetics and dynamics of CN radical reactions. Birmingham : University of Birmingham, 1992.

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Sims, Ian Richard. State-selected kinetics of CN radical reactions. Birmingham : University of Birmingham, 1989.

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Herbert, Lee Brian. The kinetics of CH and CN radical reactions. Birmingham : University of Birmingham, 1995.

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R, Leone Stephen, et United States. National Aeronautics and Space Administration., dir. Rate coefficients for reactions of ethynyl radical (C₂H) with HCN and CH₃CN : Implications for the formation of complex nitriles on Titan. [Washington, DC : National Aeronautics and Space Administration, 1997.

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Chapitres de livres sur le sujet "Radicale CN"

Neumann, W. P., et R. Stapel. « The Different Recombinations of Diphenyl Methyl Radicals Ph2 C.-R, R = tBu, CN, COOR’, COR’ ». Dans Substituent Effects in Radical Chemistry, 219–22. Dordrecht : Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4758-0_16.

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Smith, Ian W. M. « THE REACTION BETWEEN CN AND O2 : A PROTOTYPE RADICAL-RADICAL REACTION ? » Dans Advanced Series in Physical Chemistry, 214–49. World Scientific Publishing Company, 1996. http://dx.doi.org/10.1142/9789814317184_0006.

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Halpern, Joshua B., et Yuhui Huang. « Collisional electronic energy transfer in CN free radicals ». Dans Research in Chemical Kinetics, 347–87. Elsevier, 1993. http://dx.doi.org/10.1016/b978-0-444-81751-8.50011-3.

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Heaven, Michael C., Yaling Chen et William G. Lawrence. « Interactions between CN radicals and rare gas atoms ». Dans Advances in Molecular Vibrations and Collision Dynamics, 91–126. Elsevier, 1998. http://dx.doi.org/10.1016/s1063-5467(98)80005-3.

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Yang, David L., et M. C. Lin. « THE REACTIONS OF THE CN RADICAL WITH MOLECULES RELEVANT TO COMBUSTION AND ATMOSPHERIC CHEMISTRY ». Dans Advanced Series in Physical Chemistry, 164–213. World Scientific Publishing Company, 1996. http://dx.doi.org/10.1142/9789814317184_0005.

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Actes de conférences sur le sujet "Radicale CN"

Qubbaj, Ala R., et S. R. Gollahalli. « Laser-Induced Fluorescence Measurements in Venturi-Cascaded Propane Gas Jet Flames ». Dans ASME 1999 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/imece1999-1115.

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Abstract “Venturi-cascading” technique is a means to control pollutant emissions of diffusion flames by modifying air infusion and fuel-air mixing rates through changing the flow dynamics in the combustion zone with a set of venturis surrounding the flame. A propane jet diffusion flame at a burner-exit Reynolds number of 5100 was examined with a set of venturis of specific sizes and spacing arrangement. The venturi-cascading technique resulted in a decrease of 33% in NO emission index along with a 24% decrease in soot emission from the flame, compared to the baseline condition (same flame without venturis). In order to understand the mechanism behind these results, Laser Induced Fluorescence (LIF) spectroscopy was employed to study the concentration field of the radicals (OH, CH and CN) in the baseline and venturi-cascaded flames. The LIF measurements, in the near-burner region of the venturi-cascaded flame, indicated an average decrease of 18%, 24% and 12% in the concentrations of OH, CH and CN radical, respectively, from their baseline values. However, in the mid-flame region, a 40% average increase in OH, from its baseline value, was observed. In this region, CH or CN radicals were not detected. The OH radical, in the downstream locations, was mostly affected by soot rather than by temperature. In addition, prompt-NO mechanism appeared to play a significant role besides the conventional thermal-NO mechanism.

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Black, Graham, L. E. Jusinski, M. R. Taherian, T. G. Slanger et D. L. Huestis. « N ₂ ( A ³ Σ u + ) generation in photodissociated cyanogen-oxygen mixtures ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1986. http://dx.doi.org/10.1364/oam.1986.wh5.

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F2 (158-nm) and ArF (193-nm) excimer radiation has been used to photodissociate C2N2 and produce chemiluminescence in C2N2–O2 mixtures. In addition LIF measurements have followed the temporal behavior of the CN and NCO radicals. The behavior of CN is understood in terms of its reactions with O2 and O. The NCO decay is controlled by radical or atom intermediates. This study has focused on the NO γ-band chemiluminescence and evidence is presented to support the view that it arises from energy transfer from N2(A) to NO and the N2(A) is made by the reaction N(2D) + NCO → N2(A) + CO. An estimate of ≈25% is obtained for the N2(A) yield of this reaction, assuming a rate coefficient of 1 × 10−10 cm3 mor−1 s−1 (a lower rate would require a proportionately higher yield and vice versa).

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Chen, Xiangli, et Jyoti Mazumder. « Optical emission diagnostics of laser-induced graphite plasma for diamondlike film deposition ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1990. http://dx.doi.org/10.1364/oam.1990.fc5.

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Motivated by recent interest in laser graphite ablation for optical-quality diamondlike carbon-film deposition, we took emission spectra from a pulsed KrF (3 x 108 W/cm2) excimer laser-induced plasma plume on the surface of bulk graphite. A 0.3 m spectrograph and an optical multichannel analyzer (OMA) were used. In the visible region the plasma emission was dominated by the D-A swan and C-A DesIandres-d'Azambuja bands of C2 and the B-X violet band of CN. No evidence of transitions attributable to C+, C, C3, or larger carbon clusters was found. From the band emission intensity, the vibrational temperatures of the radicals were calculated from the Einstein spontaneous emission coefficients with an assumed Boltzmann population distribution. The results from the different transitions of the C2 swan and CN violet bands all fell within the range of experimental error and uncertainty error in the Einstein coefficients and indicate a vibrational temperature of (13.5 ± 1.3) x 103 K for both radicals. This excellent agreement makes one believe that the species in the plasma are likely to be in local thermodynamic equilibrium. C2 radical concentration is estimated to be 1 × 1015 cm−3 on the basis of emission intensity and Boltzmann distribution at the above temperature.

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Halpern, Joshua B. « Radiative lifetimes and energy transfer in CN(A2Πi) ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1992. http://dx.doi.org/10.1364/oam.1992.wl1.

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Radiative lifetimes were measured for the v′ = 2…7 levels of CN(A2Π i ). The results were lower than predicted by theory, although the expected decrease in lifetime with increasing vibrational excitation was observed. Rapid collisional vibrational and electronic energy transfer was also seen. Ground state CN radicals were formed by the excimer laser photolysis of C2N2, followed by dye laser excitation of CN(A). Vibrational cascading in the A state was monitored by following the emission from A state vibrational levels. Electronic energy transfer was followed by exciting LIF from high vibrational levels of the ground state.

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Bernath, Peter. « Emission Spectroscopy of Transient Molecules ». Dans High Resolution Fourier Transform Spectroscopy. Washington, D.C. : Optica Publishing Group, 1992. http://dx.doi.org/10.1364/hrfts.1992.tha1.

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The CN free radical is commonly observed in flames, in the combustion of propellants and in a variety of astronomical sources. The A2Π-X2Σ+ and the B2Σ+-X2Σ+ electronic transitions were observed in a corona-excited supersonic jet expansion source using methyl azide (CH3N3) in helium. The rotationally cold but vibrationally and electronically hot spectra of CN were recorded at high resolution during the course of our work1 on CH3N.

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Nikolai, W. L., R. C. Jensen et Robert D. Coombe. « Chemical production and reaction of metastable N(2D) for short-wavelength chemical lasers ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1986. http://dx.doi.org/10.1364/oam.1986.wh2.

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Metastable N(2D) is selectively produced (yield ≥ 85%) in the reaction of oxygen atoms and cyanogen radicals. We have made oxygen atoms at densities >1015 molecules cm−3 via the reaction of fluorine atoms with water. Yields approach 100% and modeling indicates scaling to short-wavelength chemical laser (SWCL) device levels is possible. We have also produced cyanogen radicals via the reaction of fluorine atoms with HCN and will present our results on the rate constant, CN yield, and scaling potential for this reaction. This latter category includes measurements of the rate constants for reaction of CN with various species we envision will be present in a SWCL device. N(2D) reacts rapidly with Cl2 and is constrained by spin and orbital angular momentum conservation to produce NCl(b,a). We present our results on NCl(b,a) yields and quenching by species envisioned to be present in a SWCL device.

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Fukushima, Jun, et Hirotsugu Takizawa. « IN-SITU SPECTROSCOPY AND TWO-COLOR THERMOGRAPHY DURING MICROWAVE IRRADIATION IN MATERIALS PROCESSING ». Dans Ampere 2019. Valencia : Universitat Politècnica de València, 2019. http://dx.doi.org/10.4995/ampere2019.2019.9882.

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Concentration of microwave E-field between material particles is considered to cause the enhancement of sintering1 and chemical reaction under microwave irradiation. For example, it is usually required 1700 °C to synthesize AlN by carbothermal reduction method using Al2O3 as a starting material, but microwave processing can proceed this process at 1200 °C2. To understand this phenomenon, it is necessary to understand an occurrence behavior of plasma and a chemical reaction related to radical species generated by a local E-field concentration. In addition, in material synthesis using a raw material powder of several mm, it is suggested that a selective heating in the powder scale occurs. However, to discuss this selective heating behavior on this scale, it is necessary to realize a quantitative temperature measurement system with independent of the emissivity of the material and several mm spatial resolution. In this study, we conducted an in-situ spectroscopy and two-color thermography to verify these non-equilibrium effects during microwave irradiation. For example, in the iron making process, it was investigated that CN plasma was generated, and this CN radical contributed to the reduction reaction (Fig. 1(a))3. In addition, the developed two-dimensional two-color thermography system with a high resolution of 8.8 mm/pixel was enable to discuss local temperature gradients quantitatively (Fig. 1(b)).

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Paul, A., I. McLaren, W. H. Fink et W. M. Jackson. « Polarization and Doppler measurements of CN radicals formed in the 210 NM photolysis of BrCN ». Dans AIP Conference Proceedings Volume 172. AIP, 1988. http://dx.doi.org/10.1063/1.37339.

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Gupta, Divita, Ian Sims, Mitchio Okumura, Joseph Messinger et Ilsa Cooke. « LOW-TEMPERATURE KINETICS MEASUREMENTS OF THE GAS-PHASE REACTIONS BETWEEN AROMATIC SPECIES AND THE CN RADICAL ». Dans 2020 International Symposium on Molecular Spectroscopy. Urbana, Illinois : University of Illinois at Urbana-Champaign, 2020. http://dx.doi.org/10.15278/isms.2020.fb01.

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Gupta, Divita, Ian Sims, Mitchio Okumura, Joseph Messinger et Ilsa Cooke. « LOW-TEMPERATURE KINETICS MEASUREMENTS OF THE GAS-PHASE REACTIONS BETWEEN AROMATIC SPECIES AND THE CN RADICAL ». Dans 2021 International Symposium on Molecular Spectroscopy. Urbana, Illinois : University of Illinois at Urbana-Champaign, 2021. http://dx.doi.org/10.15278/isms.2021.fc08.

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Rapports d'organisations sur le sujet "Radicale CN"

Dagdigian, Paul J., et Millard H. Alexander. Study of Elementary Reactions and Energy Transfer Processes Involving the NH and CN Free Radicals. Fort Belvoir, VA : Defense Technical Information Center, juin 1991. http://dx.doi.org/10.21236/ada238461.

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