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31.
We investigate a simple, exactly solvable model for interacting adsorbates. From the model study, we find that (1-theta)(-1) as a function of density of molecules in bulk media can have a positive curvature only in the presence of attractive interaction between adsorbed molecules. We propose a novel experimental observable, chi. Positive chi is the sufficient condition for the presence of attractive interactions between adsorbate molecules. 相似文献
32.
Francesco Mattarozzi Marisol Tapia Rosales Rim C. J. van de Poll Prof. Dr. Emiel J. M. Hensen Dr. Peter Ngene Prof. Dr. Petra E. de Jongh 《欧洲无机化学杂志》2023,26(28):e202300152
The electrochemical reduction of CO2 to produce sustainable fuels and chemicals has attracted great attention in recent years. It is shown that surface-modified carbons catalyze the CO2RR. This study reports a strategy to modify the surface of commercially available carbon materials by adding oxygen and nitrogen surface groups without modifying its graphitic structure. Clear differences in CO2RR activity, selectivity and the turnover frequency between the surface-modified carbons were observed, and these differences were ascribed to the nature of the surface groups chemistry and the point of zero charge (PZC). The results show that nitrogen-containing surface groups are highly selective towards the formation of CO from the electroreduction of CO2 in comparison with the oxygen-containing surface groups, and the carbon without surface groups. This demonstrates that the selectivity of carbon for CO2RR can be rationally tuned by simply altering the surface chemistry via surface functionalization. 相似文献
33.
34.
Young-Joo Eo Wonha Lee Kyunhwan Kim SeJin Ahn Ara Cho Jihye Gwak Kyunghoon Yoon Se Youn Moon Hyo Rim Jung Jin Hyeok Kim Jae Ho Yun 《Current Applied Physics》2014,14(10):1349-1355
Carbon-free CuInSe2 (CIS) thin film with a dense microstructure has been prepared using a novel non-vacuum based fabrication route. CuxSy and In2Se3 binary nanoparticles, approximately 10 nm in size, were synthesized by a low temperature colloidal process. The precursor film was deposited using the coating ink formulated with the binary nanoparticles and pyridine, and then annealed in the rapid thermal annealing (RTA) chamber at 540 °C for 15 min under selenium (Se) atmosphere. Scanning electron micrographs, X-ray diffraction patterns and Raman spectra showed a phase pure carbon-free and dense CIS thin film was prepared in this method. A solar cell device fabricated using this CIS thin film showed the following photovoltaic characteristics: VOC = 350 mV, JSC = 24.72 mA cm−2, FF = 38.73% and η = 3.36% under standard AM 1.5 condition. 相似文献
35.
The pharmaceutical combination of miconazole nitrate (MZ) and lidocaine hydrochloride (LD) is used in the curative and prophylactic therapy of the oral and gastro-intestinal infections caused by Candida albicans. To the best of our knowledge, no attempts have yet been made to assay this combination by any analytical method. A simple and selective high-performance liquid chromatography-diode array detection (HPLC-DAD) stability-indicating method was developed for the simultaneous determination of MZ and LD in their combined formulation. Effective chromatographic separation was achieved using a Zorbax SB-C8 column with gradient elution of the mobile phase composed of 0.05 M phosphoric acid and acetonitrile. The gradient elution started with 25% (by volume) acetonitrile, ramped up linearly to 65% in 6 min, then kept constant until the end of the run. The mobile phase was pumped at a flow rate of 1 mL/min. The multiple wavelength detector was set at 215 nm and analytes were quantified by measuring their peak areas. The retention times for LD and MZ were approximately 4.1 and 8.4 min, respectively. The reliability and analytical performance of the proposed HPLC procedure were statistically validated with respect to linearity, ranges, precision, accuracy, selectivity, robustness, detection and quantification limits. Calibration curves were linear in the ranges of 5-100 μg/ml for both drugs with correlation coefficients > 0.999. Both drugs were subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. The proposed method proved to be stability-indicating by the resolution of the two analytes from the related substance and potential impurity (2,6-dimethylaniline) and from the forced-degradation products. The validated HPLC method was applied to the analysis of MZ and LD in the combined oral gel preparation, in which the two analytes were successfully quantified and resolved from the pharmaceutical additives. The proposed method made use of DAD as a tool for peak identity and purity confirmation. 相似文献
36.
Richárd Rimányi 《Inventiones Mathematicae》2001,143(3):499-521
As an application of the generalized Pontryagin-Thom construction [RSz] here we introduce a new method to compute cohomological
obstructions of removing singularities — i.e. Thom polynomials [T]. With the aid of this method we compute some sample results,
such as the Thom polynomials associated to all stable singularities of codimension ≤8 between equal dimensional manifolds,
and some other Thom polynomials associated to singularities of maps N
n
?P
n+k
for k>0. We also give an application by reproving a weak form of the multiple point formulas of Herbert and Ronga ([H], [Ro2]).
As a byproduct of the theory we define the incidence class of singularities, which — the author believes — may turn to be
an interesting, useful and simple tool to study incidences of singularities.
Oblatum 4-II-1999 & 19-VII-2000?Published online: 30 October 2000 相似文献
37.
Dielectric materials with high indices have recently attracted much attention in the community of nanophotonics. Severe optical losses in visible–ultraviolet (UV) region, however, limit their applications. This article proposes dielectric–metal nanocomposites as alternative high-index materials for Mie-resonance-based applications. Such composite materials have high indices in the range of wavelength longer than plasmon resonance of inclusion metal nanoparticles, while they have much lower losses in the range from blue-violet down to near-UV compared with commonly used high-index materials such as silicon, enabling near-UV generation with high efficiency based on third-harmonic generation (THG). The numerical results show that ZnO nanodisk containing silver nanoparticles can generate near-UV radiation at 351.3 nm via THG with an efficiency about 20 times higher compared with silicon nanodisk under same pumping condition. Significantly high THG efficiency of 0.015% has been predicted with such a composite nanodisk supported by aluminum substrate under pumping with a peak intensity of 20 GW cm−2, a spot size of 0.8 , a duration of 50 fs at 1054 nm, respectively. 相似文献
38.
Dr. Rim Makhoul Dr. Paul Hamon Dr. Thierry Roisnel Dr. Jean-René Hamon Dr. Claude Lapinte 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(38):8368-8371
The unprecedented tetrairon dication [{Cp*(dppe)FeC≡C-}4-μ-(1,2,4,5-C6H2)](PF6)2 ( 1 ) was obtained through a sequence of three reactions from 1,2,4,5-tetraethynylbenzene, Cp*(dppe)FeCl (Cp*=C5Me5, dppe=1,2-bis(diphenylphosphino)-ethane), KOtBu, and ferrocenium hexafluorophosphate. The cyclic voltammogram of the target molecule, isolated in 77 % yield, exhibits four well separated and reversible redox events showing that 1 is thermodynamically stable with respect to disproportionation (Kc>106). The tetranuclear dication 1 was characterized by XRD on single crystal, IR and NMR spectroscopies and Mössbauer spectrometry. The experimental data show that 1 behaves as a class II mixed-valence complex with the positive charges preferentially disposed on antipodal positions. This new molecule can be regarded as a potential molecular prototype of quantum dot cellular automata. 相似文献
39.
A series of late transition metal complexes, [(bpma)Co(μ – Cl)Cl] 2 , [(bpma)Cu(μ – Cl)Cl] 2 , [(bpma)Zn(μ – Cl)Cl] 2 and [(bpma)Cd(μ – Br)Br] 2 (where bpma is 4‐bromo‐N‐((pyridin‐2‐yl)methylene)benzenamine) have been synthesized and structurally characterized. The X‐ray structures of dimeric complexes [(bpma)M(μ – X)X] 2 (M = Co, Cu and Zn, X = Cl; M = Cd, X = Br) showed a distorted 5‐coordinate trigonal bipyramidal geometry involving two nitrogen atoms of N,N‐bidentate ligand, two bridged and one terminal halogen atoms. The complex [(bpma)Cu(μ – Cl)Cl] 2 revealed the highest catalytic activity for the polymerisation of methyl methacrylate in the presence of modified methylaluminoxane with an activity of 9.14 × 104 g PMMA/mol·Cu·h at 60 °C and afforded syndiotactic poly (methylmethacrylate) (rr = 0.69). 相似文献
40.
Boo Rim Choe Hyungwoon Koo Wayne Smith 《Transactions of the American Mathematical Society》2003,355(7):2829-2855
We study the action of composition operators on Sobolev spaces of analytic functions having fractional derivatives in some weighted Bergman space or Hardy space on the unit disk. Criteria for when such operators are bounded or compact are given. In particular, we find the precise range of orders of fractional derivatives for which all composition operators are bounded on such spaces. Sharp results about boundedness and compactness of a composition operator are also given when the inducing map is polygonal.