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61.
The problem on the electric current from electrodes in a magnetizedsemiconductor film is reduced to the skew derivative problemfor the Laplace equation outside cuts in a plane. The problemfor the Laplace equation is studied under different conditionsat infinity, which have a certain physical meaning. With thehelp of potential theory, the skew derivative problem is reducedto a Fredholm integral equation of the second kind, which isuniquely solvable. The Neumann problem for the Laplace equationin the exterior of cuts in a plane is a particular case of ourproblem. 相似文献
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An analytical approach is presented to determine the performance of a tunable wavelength converter based on four wave mixing (FWM) in a single mode fiber (SMF) with two pump lasers. The analysis is carried out for an intensity modulated (IM) signal taking into considerations the effects of spectral broadening due to FWM and laser phase noise. The results evaluated at a bit rate of 10 Gb/s show that the signal power is substantially higher at lower values of wavelength separation. For example, for input powers of 10 mW each, wavelength separation of 4 nm between the pump-2 and the input signal, the output converted power is found to be –10 dBm corresponding to wavelength separation of 2 nm between pump-1 and converter signal. The corresponding crosstalk power is found to be –25 dBm at a channel separation of 3 times bit rate. 相似文献
64.
Bimetallic Ag‐Pt Sub‐nanometer Supported Clusters as Highly Efficient and Robust Oxidation Catalysts
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Dr. Fabio R. Negreiros Dr. Avik Halder Dr. Chunrong Yin Dr. Akansha Singh Dr. Giovanni Barcaro Dr. Luca Sementa Dr. Eric C. Tyo Dr. Michael J. Pellin Dr. Stephan Bartling Dr. Karl‐Heinz Meiwes‐Broer Dr. Sönke Seifert Dr. Prasenjit Sen Dr. Sandeep Nigam Dr. Chiranjib Majumder Dr. Nobuyuki Fukui Dr. Hisato Yasumatsu Dr. Stefan Vajda Dr. Alessandro Fortunelli 《Angewandte Chemie (International ed. in English)》2018,57(5):1209-1213
A combined experimental and theoretical investigation of Ag‐Pt sub‐nanometer clusters as heterogeneous catalysts in the CO→CO2 reaction (COox) is presented. Ag9Pt2 and Ag9Pt3 clusters are size‐selected in the gas phase, deposited on an ultrathin amorphous alumina support, and tested as catalysts experimentally under realistic conditions and by first‐principles simulations at realistic coverage. In situ GISAXS/TPRx demonstrates that the clusters do not sinter or deactivate even after prolonged exposure to reactants at high temperature, and present comparable, extremely high COox catalytic efficiency. Such high activity and stability are ascribed to a synergic role of Ag and Pt in ultranano‐aggregates, in which Pt anchors the clusters to the support and binds and activates two CO molecules, while Ag binds and activates O2, and Ag/Pt surface proximity disfavors poisoning by CO or oxidized species. 相似文献
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Nicole Kunesch Yves Rolland Jacques Poisson P. L. Majumder R. Majumder A. Chatterjee Vincent C. Agwada Jorge Naranjo Manfred Hesse Hans Schmid 《Helvetica chimica acta》1977,60(8):2854-2859
The Structure of bis-indoline alkaloids of a novel type The structure of folicangine 4 , a bis-indoline alkaloid from the leaves of Voacanga africana, is obtained by correlation with voafolidine 3a and isovoafolidine 3b . It requires an ether bridge between the two parts of the molecule, as in subsessiline (amataine 5a ). Subsessiline-lactone, from the leaves of Voacanga thouarsii has structure 5b proved by correlation with 5a . The CD. curves of double-indole alkaloids of vobtusine type are given (Table 3). 相似文献
68.
A linear system of dimension D can be embedded by D time-delay vectors. However, a nonlinear system often requires more vectors,
almost always not more than 2D+1. This paper is regarding the consequence of such an embedding. We encountered this problem
in an attempt to obtain a set of equations from the observed data. Our goal was to generate a system which is topologically
conjugate to the original system. We found that many a times our efforts led to highly unstable systems. Now, we have an explanation.
Embedding in higher dimensions causes a topological foliation and this foliation has a D-dimensional “leaf”. All the data
were on this leaf and therefore we were unable to distinguish this foliated system from those where the foliation had collapsed.
We illustrate the phenomenon by examples from numerically generated data and suggest possible remedies. 相似文献
69.
Novozym 435 (a commercially available immobilized form of Candida antarctica lipase B) was found to catalyze a condensation reaction of 5-hydroxy-endo-tricyclo[5.2.1.02,6]deca-4,8-dien-3-one with acetaldehyde (enzymatically produced from vinyl acetate in situ) under low water conditions, in presence of 10% organic co-solvent (N,N-dimethyl formamide or pyridine), to form a bis-adduct. Even though the condensation reaction occurred with pyridine (acting as a base catalyst) in the presence of acetaldehyde and in the absence of enzyme, the reaction was very slow as compared to the enzymatic process. Thus, while the non-enzymatic process took 4 days to achieve 100% conversion; in presence of enzyme it was possible within 4 h. 相似文献
70.
The Neumann problem for the propagative Helmholtz equation inthe exterior of several bodies (obstacles) is studied in twoand three dimensions by a special modification of the boundaryintegral equation method. This modification can be called the'method of interior boundaries', because additional boundariesare introduced inside scattering bodies. The solution of theproblem is obtained in the form of a single layer potentialon the whole boundary. The density in the potential satisfiesthe uniquely solvable Fredholm equation of the second kind andcan be computed by standard codes. In fact our method holdsfor any positive wave numbers. 相似文献