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121.
We study the adsorption of homogeneous or heterogeneous polymers onto heterogeneous planar surfaces with exponentially decaying site-site correlations, using a variational reference system approach. As a main result, we derive simple equations for the adsorption-desorption transition line. We show that it is preferable to have a small amount of strongly adsorbing sites or monomers rather than a greater amount of weakly adsorbing ones. The results are discussed with respect to their implications for the physics of molecular recognition. 相似文献
122.
We applied a finite-difference time domain algorithm to the study of field and intensity correlations in random media. Close to the onset of Anderson localization, we observe deviations of the correlation functions, in both shape and magnitude, from those predicted by the diffusion theory. Physical implications of the observed phenomena are discussed. 相似文献
123.
Stable soliton complexes in two-dimensional photonic lattices 总被引:2,自引:0,他引:2
We show that two-dimensional photonic Kerr nonlinear lattices can support stable soliton complexes composed of several solitons packed together with appropriately engineered phases. This may open up new prospects for encoding pixellike images made of robust discrete or lattice solitons. 相似文献
124.
Karajanagi SS Vertegel AA Kane RS Dordick JS 《Langmuir : the ACS journal of surfaces and colloids》2004,20(26):11594-11599
We have examined the structure and function of two enzymes, alpha-chymotrypsin (CT) and soybean peroxidase (SBP), adsorbed onto single-walled carbon nanotubes (SWNTs). SBP retained up to 30% of its native activity upon adsorption, while the adsorbed CT retained only 1% of its native activity. Analysis of the secondary structure of the proteins via FT-IR spectroscopy revealed that both enzymes undergo structural changes upon adsorption, with substantial secondary structural perturbation observed for CT. Consistent with these results, AFM images of the adsorbed enzymes indicated that SBP retains its native three-dimensional shape while CT appears to unfold on the SWNT surface. This study represents the first in depth investigation of protein structure and function on carbon nanotubes, which is critical in designing optimal carbon nanotube-protein conjugates. 相似文献
125.
126.
127.
Cholinesterase sensors based on screen-printed electrodes for detection of organophosphorus and carbamic pesticides 总被引:4,自引:0,他引:4
Ivanov A Evtugyn G Budnikov H Ricci F Moscone D Palleschi G 《Analytical and bioanalytical chemistry》2003,377(4):624-631
Cholinesterase sensors based on screen-printed electrodes modified with polyaniline, 7,7,8,8-tetracyanoquinodimethane (TCNQ), and Prussian blue have been developed and tested for detection of anticholinesterase pesticides in aqueous solution and in spiked grape juice. The influence of enzyme source and detection mode on biosensor performance was explored. It was shown that modification of the electrodes results in significant improvement of their analytical characteristics for pesticide determination. Thus, the slopes of the calibration curves obtained with modified electrodes were increased twofold and the detection limits of the pesticides were reduced by factors of 1.6 to 1.8 in comparison with the use of unmodified transducers. The biosensors developed make it possible to detect down to 2×10–8 mol L–1 chloropyrifos-methyl, 5×10–8 mol L–1 coumaphos, and 8×10–9 mol L–1 carbofuran in aqueous solution and grape juice. The optimal conditions for grape juice pretreatment were determined to diminish interference from the sample matrix.Abbreviations ChE Cholinesterase - TCNQ 7,7,8,8-Tetracyanoquinodimethane - ChO Choline oxidase - AChE Acetylcholinesterase - BChE Butyrylcholinesterase - BSA Bovine serum albumin - 2-PAM 2-Pyridine aldoxime methiodide 相似文献
128.
French SA Sokol AA Bromley ST Catlow CR Rogers SC King F Sherwood P 《Angewandte Chemie (International ed. in English)》2001,40(23):4437-4440
129.
Alexey A. Morozov 《Applied Physics A: Materials Science & Processing》2013,111(4):1107-1112
A theoretical study of the time-of-flight (TOF) distributions under pulsed laser ablation has been performed. 2D simulations of pulsed evaporation of atoms into vacuum on the base of the direct simulation Monte Carlo (DSMC) method have been carried out. It is found that for large evaporating spots (when the spot radius exceeds the initial plume length by a factor of five) the TOF distributions practically do not change with the spot radius variation. Moreover, it is shown that such distributions can be obtained from 1D calculations. Thus, in the frames of 1D approach, the TOF distribution is a function only of the number of the evaporated monolayers, but not of the spot radius. The shape of the TOF distribution is shown to strongly depend on the amount of the evaporated matter. Based on the calculated TOF distributions, dependence of the particle kinetic energy on the number of the evaporated monolayers has been obtained. To verify the theoretical results, experimental data on laser ablation of niobium and mercury have been used, which confirm the obtained dependences. The obtained results allow estimating the irradiated surface temperature from the TOF distributions for monatomic neutral gas. 相似文献
130.
Alexey N. Egorochkin Nadiya M. Khamaletdinova 《Journal of organometallic chemistry》2011,696(10):2199-2205
The literature data on substituent influence on the CS, CN, NC, NN, and NO stretching frequencies (ν) in the IR spectra and in specific cases on their respective stretching force constants (k) have been analyzed for 28 series of the transition metal complexes. The ν and k values were first established to depend not only on the inductive and resonance effects but on the polarizability of substituents as well. The contribution of the polarizability effect varies from 0 to 57% with the type of series. 相似文献