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991.
Gcineka Mbambisa 《Microchemical Journal》2009,93(1):60-66
Self-assembled monolayers (SAMs) based on octapentylthiophthalocyanine complexes of oxovanadium (IV) (OVOPThPc), titanium(IV) (OTiOPThPc), and manganese (III) acetate (AcMnOPThPc), and of tetraphenylthiophthalocyanine complexes of hydroxo manganese(III) (OHMnTPPc) and oxotitanium(IV) (OTiTPPc) are described. The oxidation of l-cysteine was observed at potentials which ranged from 0.52 V to 0.67 V. The detection limits for l-cysteine analysis were of the order of 10− 7 to 10− 6 M. 相似文献
992.
Leland Rosenberger Ronald Baird Erik McCullen Gregory Auner Gina Shreve 《Surface and interface analysis : SIA》2008,40(9):1254-1261
Ten samples of crystalline aluminum nitride (AlN) film were deposited on sapphire and silicon substrates by a plasma source molecular beam method. The samples were analyzed using X‐ray photoelectron spectroscopy (XPS) depth profiling and high‐resolution X‐ray diffraction. Oxygen levels were observed to decrease exponentially from the surface into the bulk film. Aluminum, nitrogen and oxygen peaks were fitted with subpeaks in a consistent manner and the subpeaks were assigned to chemical states. AlN subpeaks were observed at 73.5 eV for Al2p and 396.4 eV for N1s. An N1s subpeak at 395.0 eV was assigned to N? N defects. No direct N? O bonds are assigned; rather it is proposed that an N? Al? O bond sequence is the source of higher binding energy N1s subpeaks. The observations in this study support a model in which oxygen is bound only to aluminum in the form of Al? O octahedral complexes dispersed or clustered throughout the main AlN matrix or as Al? O bonds on the crystal grain boundaries. The data also suggest that the AlN lattice parameters are related to oxygen content, since the c‐axis is observed to increase with increasing oxygen content. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
993.
We examine the effect of a hexagonal boron nitride (hBN) substrate on electron transport through graphene nanojunctions just before gap formation. Junctions in vacuum and on hBN are formed using classical molecular dynamics to create initial structures, followed by relaxation using density functional theory. We find that the hBN only slightly reduces the current through the junctions at low biases. Furthermore due to quantum interference at the last moments of breaking, the current though a single carbon filament spanning the gap is found to be higher than the current through two filaments spanning the gap in parallel. This feature is present both in the presence of absence of hBN. 相似文献
994.
S. Marimuthu A.M. Kamara D. Whitehead P. Mativenga L. Li 《Optics & Laser Technology》2010,42(8):1233-1239
Current environmental challenges require sustainable and extended use and re-use of materials. For example, the service life of engineering tooling can be extended by using thin film coatings such as titanium nitride (TiN). However, when errors arise in the coating process or when the tooling needs to be re-used it is necessary to remove the coating. Decoating is also useful when a large batch of cutting tools needs to be re-directed for a different application, which requires a new generation of coating. Existing technology uses chemical methods which are not environmentally friendly or ideal for selective removal. In this work, excimer laser striping of TiN from coated tungsten carbide (WC) micro-tools has been demonstrated as a viable alternative to chemical methods. Also, in order to raise the integrity of the decoating process and to make the process more accurate and reliable, two online monitoring systems were developed exploiting probe beam reflection (PBR) and laser plume emission spectroscopy (PES). The online monitoring system facilitated a simultaneous prediction of surface elements as coating layers are progressively removed and ensures better control over the laser irradiation process so as to avoid under or over stripping of the coating. 相似文献
995.
Krasovsky A. L. Pissarev S. A. Nenajdenko V. G. Balenkova E. S. 《Russian Chemical Bulletin》2003,52(8):1791-1796
A procedure was developed for the synthesis of previously unknown CF3-containing -azolyl-substituted enones by the reactions of 1,1,1-trifluoro-4-sulfonyl-3-butene-2,2-diols with various azoles. Quaternization of the azolyl group with methyl triflate afforded -azolium-substituted enones in quantitative yields. 相似文献
996.
997.
998.
Winfried Plass 《无机化学与普通化学杂志》1997,623(8):1290-1298
Oxovanadium(IV) Complexes with Multidentate Amine Alcohol Ligands: Magneto-Structural Correlations for the {VO(μ-OR)2VO} Core The trivalent, pentadentate amine alcohol ligand 1,1-bis(2-hydroxyethyl)-4-(2-hydroxybenzyl)-1,4-diazabutane (H3hebab) reacts with [VO(acac)2] in methanol solution to yield the binuclear oxovanadium(IV) complex [{VO(Hhebab)}2] with a {VO(μ-OR)2VO}2+ core. The compound has been characterized by vibrational (IR, Raman), UV/Vis/NIR, and ESR spectroscopy and the measurement of the magnetic susceptibility in the temperature range of 2 to 280 K. A classification is given for the correlation of the configuration of the {VO(μ-OR)2VO} core and the magnetic properties of the related oxovanadium(IV) complexes. Antiferromagnetic interactions are operative in the case of anti-and syn-orthogonal as well as syn-coplanar configurations. whereas in the case of anti-coplanar and twist configurations ferromagnetic interactions are observed. Based on the antiferromagnetic behavior of [{VO(Hhebab)}2] with J = ?170 cm?1 this classification allows together with the spectroscopic data and density functional calculations the unequivocal assignment of an anti-orthogonal configuration for its {VO(μ-OR)2VO}2+ core. The structural and magnetic data of a series of oxovanadium(IV) complexes with anti- and syn-orthogonal {VO(μ-OR)2VO} core are used to investigate the quantitative correlation between the V(IV) …? V(IV) distance and the corresponding isotropic interaction constant J. 相似文献
999.
1000.
Summary The oxidation of 2,2-Diacyl-1-arylhydrazines1a–l with the system Pb(OAc)4-CF3COOH-CH2Cl2 led to the formation of two types of radical products. Phenazinium cation radicals5a–h were formed from 2,2-diacyl-1-arylhydrazines1a–h, while hydrazyl radicals2i–l were observed to be the only radical products of the oxidation of1i–l. The generated radicals are characterized by their EPR parameters.
Radikalische Produkte der Oxidation von 2,2-Diacyl-1-arylhydrazinen mit dem System Pb(OAc)4-CF3COOH-CH2Cl2
Zusammenfassung Die Oxidation der 2,2-Diacyl-1-arylhydrazine1a–l mit dem System Pb(OAc)4-CF3COOH-CH2Cl2 führte zu zwei unterschiedlichen Typen von Radikalen. Aus den 2,2-Diacyl-1-arylhydrazinen1a–h werden die Phenaziniumkationenradikale5a–h gebildet, während nach Oxidation von1i–l die entsprechenden Hydrazyle2i–l als einzige Radikalprodukte nachweisbar waren. Die erzeugten Radikale wurden durch ihre EPR-Parameter charakterisiert.相似文献