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141.
The first experimental detection of CS(2)OH is reported. CS(2)OH was observed for about one microsecond after its formation, as an intact isolated species in the gas phase. It was generated by electron transfer to the CS(2)OH(+) ion, prepared in the source of a multisector mass spectrometer by suitable ion-molecule reactions. The vertical formation process allowed characterization of CS(2)OH by structural analysis of CS(2)OH(+). Theoretical calculations were performed at the B3LYP/6-311+G(2d,p) and CCSD(T)/aug-cc-pVTZ//B3LYP/6-311+G(2d,p) levels of theory. The computed structure and stability of CS(2)OH and CS(2)OH(+) as well as the energetics of the involved processes satisfactorily fit with the experimental results. 相似文献
142.
Laurence Rozes Nathalie Steunou Giulia Fornasieri Clément Sanchez 《Monatshefte für Chemie / Chemical Monthly》2006,137(5):501-528
Summary. This review describes the major advances made on titanium-oxo clusters chemistry and their derived hybrid materials. The main
synthesis procedures, the cluster structures presented in literature, and the relation between the titanium-oxo clusters condensation
degree and poisoning ratio are discussed. The tuned organo-functionalisation of the titanium-oxo based nanobuilding blocks
allows to develop a LEGO-like chemistry, able to direct the assembling of a large variety of structurally well defined complex
hybrid architectures. 相似文献
143.
We have carried out a series of ab initio calculations to investigate changes in the optical properties of Si quantum dots as a function of surface passivation. In particular, we have compared hydrogen-passivated dots with those having alkyl groups at the surface. We find that, while on clusters with reconstructed surfaces complete alkyl passivation is possible, steric repulsion prevents full passivation of Si dots with unreconstructed surfaces. In addition, our calculations show that steric repulsion may have a dominant effect in determining the surface structure and eventually the stability of alkyl-passivated clusters, with results dependent on the length of the carbon chain. Alkyl passivation weakly affects optical gaps of silicon quantum dots, while it substantially decreases ionization potentials and electron affinities and affects their excited state properties. On the basis of our results, we propose that alkyl-terminated quantum dots may be size selected, taking advantage of the change in ionization potential as a function of the cluster size. 相似文献
144.
Prof. Dr. Giulia de Petris Prof. Dr. Marzio Rosi Dr. Ornella Ursini Dr. Anna Troiani 《化学:亚洲杂志》2013,8(3):588-595
The H.‐atom transfer (HAT) reaction is investigated in the gas phase, starting from two different entrance channels, O2.+/CH2X2 and CH2X2.+/O2 (X=F, Cl), that correspond to a step of hydride transfer and to HAT, respectively. Analysis of the spin and charge along the reaction pathway shows that HAT occurs through the same reacting configuration, irrespective of whether the reactants are formed within the complex or are free isolated species. 相似文献
145.
146.
147.
Giulia Samorì Chiara Samorì Rossella Pistocchi 《Applied biochemistry and biotechnology》2014,173(1):74-89
The objective of the present study was to evaluate the nutrient removal efficiency and the physiological responses in terms of growth, biochemical composition and photosynthetic activity of the autochthonous freshwater algal strain Desmodesmus communis. Microalgae were grown in a primary municipal effluent under different hydraulic retention times (HRTs) and in a two-phases process using both primary and secondary wastewater effluents. Semi-continuous cultures were operated for 7 day at 5-, 3- and 1.5-day HRT and the different dilution rate showed a greater influence on the biomass composition and nutrient removal efficiency. Removal of N-NH3 and P-PO4 was over 99 % and the highest accumulation of polysaccharides (57.2 wt.%) was obtained at high HRT (5 day); the maximum content of proteins (26.9 wt.%) was achieved at 1.5-day HRT, even if, under this condition, a clear inefficiency in terms of ammonia removal was observed. Moreover the accumulation of N-NH3 occurring at 1.5-day HRT caused the decrease of the photosynthetic response in terms of efficiency of light capture (α) and relative electron transport rate (rETR), both parameters extracted from the rapid light curves (RLC) measurements. No significant differences were observed for the total fatty acids (TFAs), with a content of 2–3.5 wt.% for each HRT condition. On the other hand, in the two-phases process, when a nutrient deprivation condition was induced by diluting the culture with the secondary wastewater effluent, the algal cells accumulated TFAs, achieving a maximum content of 9.7 wt.% and a great increment in terms of biomass (1.64?±?0.02 g L?1) due to the ability of this algal strain to accumulate intracellular N. The wide and accurate investigation of the different aspects related to the whole process represents a relevant point of novelty in this research field and suggests the operational conditions for the start-up of an open pond system for wastewater treatment and biomass production for further applications. 相似文献
148.
Yanchao Lyu Dr. Giulia Marafon Dr. Álvaro Martínez Prof. Dr. Alessandro Moretto Prof. Dr. Paolo Scrimin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(50):11758-11764
Peptide sequences functionalized with primary amines at the N- and C-terminus are able to induce the aggregation of gold nanoparticles in ethanol as a consequence of their folding into a helical conformation. Random coil peptides are unable to induce such an aggregation process. Aggregation can be monitored spectrophotometrically by following the shift of the surface plasmon resonance (SPR) band of the nanoparticles and is confirmed by transmission electron microscopy and dynamic light scattering analyses. Partial denaturation of the peptides results in diminished cross-linking ability. The helicity parameter θ222/θ208 correlates fairly well with the shift of the SPR band to longer wavelengths, supporting the relationship between the amount of helical content of a peptide sequence and its ability to induce aggregation. 相似文献
149.
We find Riemannian metrics on the unit ball of the quaternions, which are naturally associated with reproducing kernel Hilbert spaces. We study the metric arising from the Hardy space in detail. We show that, in contrast to the one-complex variable case, no Riemannian metric is invariant under all regular self-maps of the quaternionic ball. 相似文献
150.