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101.
Xiaonan Duan Dr. Stéphane C. Corgié Prof. Daniel J. Aneshansley Prof. Peng Wang Prof. Larry P. Walker Prof. Emmanuel P. Giannelis 《Chemphyschem》2014,15(5):974-980
We report a new family of hierarchical hybrid catalysts comprised of horseradish peroxidase (HRP)–magnetic nanoparticles for advanced oxidation processes and demonstrate their utility in the removal of phenol from water. The immobilized HRP catalyzes the oxidation of phenols in the presence of H2O2, producing free radicals. The phenoxy radicals react with each other in a non‐enzymatic process to form polymers, which can be removed by precipitation with salts or condensation. The hybrid peroxidase catalysts exhibit three times higher activity than free HRP and are able to remove three times more phenol from water compared to free HRP under similar conditions. In addition, the hybrid catalysts reduce substrate inhibition and limit inactivation from reaction products, which are common problems with free or conventionally immobilized enzymes. Reusability is improved when the HRP–magnetic nanoparticle hybrids are supported on micron‐scale magnetic particles, and can be retained with a specially designed magnetically driven reactor. The performance of the hybrid catalysts makes them attractive for several industrial and environmental applications and their development might pave the way for practical applications by eliminating most of the limitations that have prevented the use of free or conventionally immobilized enzymes. 相似文献
102.
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104.
Bennett N. Walker Jessica A. Stolee Deanna L. Pickel Scott T. Retterer Akos Vertes 《Applied Physics A: Materials Science & Processing》2010,101(3):539-544
Experimental assessment of the thermal load induced by fast laser pulses on micro- and nanostructures through IR imaging is
currently too slow and lacks the spatial resolution to be useful. In this paper, we introduce a method based on measuring
the laser-induced yields of ions to compare the thermal loads on nanofabricated silicon structures, when exposed to nanosecond
laser pulses. The laser fluences at which the ion yields of, for example, sodiated and potassiated peptides ions are equal
for two different structures correspond to equivalent thermal loads. Using alkalinated peptides is a convenient choice because
the corresponding ion intensities are easily measured up to the melting point of silicon. As an example, we compare the nanosecond
laser heating of silicon nanopost arrays with diverse post diameters and periodicities. Assessment of the thermal load through
ion yield measurements can also be used to verify model assumptions for heat transport regimes in nanostructures. 相似文献
105.
106.
Under sections 73 and 74 of the revised Canadian Environmental Protection Act (CEPA 1999), Environment Canada and Health Canada must "categorize" and "screen" about 23,000 substances on the Domestic Substances List (DSL) for persistence (P), bioaccumulation (B), and inherently toxic (iT) properties. Since experimental data for P, B and iT are only available for a few DSL substances, a workshop was held to address issues associated with the use of Quantitative Structure-Activity Relationships (QSARs) to categorize these substances. This paper describes the results of an 11-12 November 1999 International Workshop sponsored by Environment Canada to discuss potential uses and limitations of QSARs to categorize DSL substances as either persistent or bioaccumulative and iT to non-human organisms and to recommend future research needed to develop methods for predicting the P, B and iT of difficult-to-model substances. 相似文献
107.
A pulsed jet cavity Fourier transform microwave spectrometer has been used to measure the rotational spectra of OCAgX (X = F, Cl, Br) in the frequency range 5-22 GHz. Metal atoms were generated via laser ablation and were allowed to react with CO and a halide precursor, prior to stabilization of the products within a supersonic jet of argon. These are the first experimental observations of OCAgF and OCAgBr, and the first high resolution spectroscopic study of OCAgCl. All three molecules are linear. Accurately determined rotational constants have been used to evaluate the various internuclear distances, which are found to be consistent with trends established for OCAuX and OCCuX species. The C-O distances are short, and the M-C distances are significantly longer than those in other molecules containing a metal-carbonyl bond. Precise values of centrifugal distortion constants and halogen nuclear quadrupole coupling constants have also been determined. The coupling constants are compared with the results of previous studies of OCCuX and OCAuX and are used to infer trends in the electron distributions of the molecules. Ab initio calculations have been performed and employed to predict the geometries, vibrational frequencies, and Mulliken valence orbital populations of the various species. 相似文献
108.
Lormann ME Walker CH Es-Sayed M Bräse S 《Chemical communications (Cambridge, England)》2002,(12):1296-1297
Synthesis of novel fluoronitroaryl triazenes in liquid phase and on solid support have been described; mild displacement of the fluoride ion with various nucleophiles provides access to substituted arenes which in turn can be cleaved to provide a unique access to 1-alkyl-5-nitro-1H-benzotriazole. 相似文献
109.
Noncovalent engineering of carbon nanotube surfaces by rigid,functional conjugated polymers 总被引:8,自引:0,他引:8
Chen J Liu H Weimer WA Halls MD Waldeck DH Walker GC 《Journal of the American Chemical Society》2002,124(31):9034-9035
We report a new nonwrapping approach to noncovalent engineering of carbon nanotube surfaces by short, rigid functional conjugated polymers, poly(aryleneethynylene)s. Our technique not only enables the dissolution of various types of carbon nanotubes in organic solvents, which represents the first example of solubilization of carbon nanotubes via pi-stacking without polymer wrapping, but could also introduce numerous neutral and ionic functional groups onto the carbon nanotube surfaces. 相似文献
110.
Laser-induced fluorescence is used to characterize the axial velocity and temperature field at the exit plane of a low-power
helium arcjet. Two cases were examined, one in which the mass-flow rate was changed at a constant current, and the other where
the current was changed at a constant mass-flow rate. At constant mass-flow rate, the velocity scales with the increase in
power. At constant current, a higher specific energy results in an unexpected lower mean exit velocity. The temperature profiles
show that the nozzle-wall temperature is greater than the mean exit temperature. Along the axis of the arcjet, these measurements
indicate the presence of a shock less than one nozzle diameter downstream of the exit.
Received: 10 July 2002 / Published online: 22 November 2002
RID="*"
ID="*"Corresponding author. Fax: +1-650-723-1748, E-mail: qwalker@stanford.edu 相似文献