The novel metal–organic framework Co2(bdda)1.5(OAc)1·5H2O (UoB‐3) was synthesized via a simple method at room temperature. UoB‐3 was characterized by the different methods, including X‐ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT‐IR), N2‐adsorption/desorption and elemental analysis. The catalytic ability of UoB‐3 was detected to be excellent for primary and secondary alcohols oxidation reaction with high yields under solvent‐free conditions. Moreover, UoB‐3 was highly active for Henry reaction of different aldehydes with nitromethane in water as a green solvent. The nanocatalyst can be recycled for five consecutive cycles without losing its activity and structural rigidity. The antibacterial activity of UoB‐3 nanostructures towards Gram‐negative bacteria, Escherichia coli and Gram‐positive bacteria, Bacillus cereus was also evaluated by using an inhibition zone test. These nanostructures exhibited strong antibacterial effect against both of them. The purpose of this study was the developing metal–organic framework materials with the enhanced activity in various fields. 相似文献
This study provides details of the electronic and optical structures and binding energies of sarin (SF) and chlorosarin (SC) with Al–N and Al–P surfaces of Al12N12 and Al12P12 nanoclusters in the gas phase. The adsorption mechanism of SF and SC on these nanoclusters containing the Al3+ central cation was studied. Optimized geometries and thermodynamic parameters of SF and SC adsorption complexes were calculated. SF and SC are chemisorbed on these nanoclusters because of the formation of PO···Al bonds. The chemical bond is formed between an oxygen atom of SF and SC and an aluminum atom of fullerene-likes (chemisorption). However, the binding energies of the complexes with the Al12N12 nanocluster are larger than these values for the Al12P12 nanocluster. The interaction enthalpy and Gibbs free energy of all studied systems were found to be negative. We can conclude that SF and SC will be adsorbed preferably on Al12N12 nanocluster. 相似文献
We have studied dietary supplements containing sea-buckthorn (Hippophae rhamnoides), bilberry (Vaccinium myrtillus), and cranberry (Vaccinium vitis-idaea) by use of thin-layer chromatography (TLC), image analysis, and UV–visible spectroscopy. The results were subjected to multivariate techniques, for example cluster analysis (CA), principal-components analysis (PCA), and linear discriminant analysis (LDA). Evaluation of the discriminating power of TLC coupled with digital image analysis for characterization of the supplements was performed by use of chemometrics. Zero-order, first-order, and normalized zero-order UV–visible spectra of extracts of fruit and dietary supplements were digitized and used in the chemometric analysis. To increase the relevance of the study, the dietary supplement extracts were compared with extracts of the natural fruit. Results obtained by application of CA, PCA, and PCA–LDA to the chromatograms suggest the possibility of discrimination among dietary supplements on the basis of the raw material used for their preparation.
A sensitive and convenient method for acidic catecholamine metabolites (including homovanillic acid, vanillylmandelic acid, 3,4‐dihydroxymandelic acid, and 3,4‐dihydroxyphenylacetic acid) determination was developed based on thin‐layer chromatography and image‐processing analysis. The metabolites were separated without a prederivatization step using reversed phase RP‐18W high‐performance plates. The mobile phase composition, detection, and quantification conditions were systematically investigated through several trials. The reaction with 2,2‐diphenyl‐1‐picrylhydrazyl radical allowed specific detection of acidic catecholamine metabolites with a high sensitivity and a wide linear range. The limit of detection and the limit of quantification were in the range of 13–103 and 18–120 ng/spot, respectively, in all cases. Mean recoveries determined were in the range 95–106% for all of the investigated compounds. The proposed method allowed rapid simultaneous determination of acidic catecholamine metabolites from spiked human urine sample. 相似文献
The ignition and combustion of coal particles are investigated numerically under conventional and oxy-fuel atmospheres. Devolatilization is computed using the chemical percolation devolatilization (CPD) model. The CPD model is coupled with a Lagrangian particle tracking method in the framework of a multiphysics, multiscale Navier–Stokes solver. Combustion in the gas phase is described using finite rate chemistry. The numerical results for ignition are compared with available experimental data and a remarkably good agreement is observed. The effect on flame ignition of the different phases characterizing the release of volatile gases is assessed. These different phases manifest themselves in two distinct peaks in the devolatilization rate and it is observed that ignition can occur during the first volatile release or on the onset of the second, depending on the particle size and gas temperature. It is found that an increase of ignition delay time in oxy-atmosphere compared to the air case is related to the depletion of radicals that react with the abundant carbon dioxide of the oxy-atmosphere, while the increased heat capacity of the mixture does not play a role. 相似文献
Myogenic autoregulation of cerebral blood flow is one of the mechanisms affecting cerebral hemodynamics. Short or long-lasting changes in intracranial pressure (ICP) are believed to reveal the responses of the cerebral system to myogenic stimuli. Through the incorporation of a theoretical model into the experimental measurements of cerebrovascular distensibility and compliance in patients with traumatic brain injury (TBI), the current study is an attempt to explain ICP dynamics in either presence or absence of cerebral autoregulation. The pulse wave velocity and transfer function between arterial blood pressure and ICP were utilized as the major tools to reflect variations in the mechanical properties of distant cerebral artries/arteriols. The results imply that different states of cerebral autoregulation and associated regimes within the cerebrovascular system can lead to different types of interrelationship between the slow variations of ICP, cerebral arterial distensibility, and compliance. Consequently, each of these classes may require different types of treatment on patients with TBI. 相似文献
In this paper, we demonstrate the unique ability of a newly developed slow-trap profiling technique to characterise silicon-based MOS capacitors in strong inversion. We also demonstrate the applicability of the slow-trap profiling technique for the characterisation of oxides grown on SiC. The obtained slow-trap profiles show that NO nitridation eliminates while N2O creates defects acting as slow traps in the case of both Si and SiC substrates. The corresponding effects of nitridation on interface traps and fixed oxide charge are also discussed. 相似文献