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91.
Micro-sized void spheres are successfully generated in a solid polymer by use of a tightly focused femtosecond laser beam from a high-repetition-rate laser oscillator. Confocal reflection images show that the void spheres are longitudinal rotational symmetric ellipsoids with a ratio of long to short axes of approximately 1.5. Layers of void spheres are then stacked to create three-dimensional diamond-lattice photonic crystals. Three gaps are observed in the [100] direction with a suppression rate of the second gap of up to approximately 75% for a 32-layer structure. The observed first- and second-order gaps shift to longer and shorter wavelengths, respectively, as the angle of incidence increases. 相似文献
92.
[reaction: see text] The directing ability of an aziridine group for the epoxidation of adjacent double bonds is demonstrated. The aziridine group is also used to effectively protect a double bond in a cycloenone system for a short synthesis of the title compound. 相似文献
93.
The possibility to detect and prospectively to characterize deposited organic layers directly on Spreeta sensors by Fourier transform Raman spectroscopy was studied. A special holder of sensors that enabled measurement of FT Raman spectra was developed. The effects of various angles of incidence of the laser beam on the sensor surface were studied with respect to the intensity of Raman spectra and to the risks of artifacts. No effect of measurement of FT Raman spectra on SPR functionality of sensors was proven. The key role of the surface morphology of the sensing gold layer on repeatability of SPR curves and the possibility to check the surface by optical microscopy was demonstrated. 相似文献
94.
The 0/1 primal separation problem is: Given an extreme point xˉ of a 0/1 polytope P and some point x
*, find an inequality which is tight at xˉ, violated by x
* and valid for P or assert that no such inequality exists. It is known that this separation variant can be reduced to the standard separation
problem for P.
We show that 0/1 optimization and 0/1 primal separation are polynomial time equivalent. This implies that the problems 0/1
optimization, 0/1 standard separation, 0/1 augmentation, and 0/1 primal separation are polynomial time equivalent.
Then we provide polynomial time primal separation procedures for matching, stable set, maximum cut, and maximum bipartite
graph problems, giving evidence that these algorithms are conceptually simpler and easier to implement than their corresponding
counterparts for standard separation. In particular, for perfect matching we present an algorithm for primal separation that
rests only on simple max-flow computations. In contrast, the known standard separation method relies on an explicit minimum
odd cut algorithm. Consequently, we obtain a very simple proof that a maximum weight perfect matching of a graph can be computed
in polynomial time.
Received: August 20, 2001 / Accepted: April 2002 Published online: December 9, 2002
RID="⋆"
ID="⋆" This research was developed while the author was on leave at the Istituto di Analisi dei Sistemi ed Informatica, Viale
Manzoni 30, 00185 Roma, supported by the project TMR-DONET nr. ERB FMRX-CT98-0202 of the European Union.
Mathematics Subject Classification (2000): 90C10, 90C60, 90C57 相似文献
95.
We explain the (non-)validity of close-to-equilibrium entropy production principles in the context of linear electrical circuits.
Both the minimum and the maximum entropy production principles are understood within dynamical fluctuation theory. The starting
point are Langevin equations obtained by combining Kirchoff’s laws with a Johnson-Nyquist noise at each dissipative element
in the circuit. The main observation is that the fluctuation functional for time averages, that can be read off from the path-space
action, is in first order around equilibrium given by an entropy production rate.
That allows to understand beyond the schemes of irreversible thermodynamics (1) the validity of the least dissipation, the
minimum entropy production, and the maximum entropy production principles close to equilibrium; (2) the role of the observables’
parity under time-reversal and, in particular, the origin of Landauer’s counterexample (1975) from the fact that the fluctuating
observable there is odd under time-reversal; (3) the critical remark of Jaynes (1980) concerning the apparent inappropriateness
of entropy production principles in temperature-inhomogeneous circuits. 相似文献
96.
The inhibition of the oxygen evolution rate (OER) in Chlorella vulgaris by 2-alkylsulphanyl-4-pyridinecarbothioamides (APCTs; alkyl = methyl up to hexadecyl) was studied. APCTs were found to inhibit
photosynthetic electron transport (PET) which resulted in the inhibition of OER in algae. The inhibitory activity of APCTs
was highly dependent on the alkyl chain length of the 2-alkylsulphanyl substituent and the corresponding dependence showed
a bilinear course with the decyl derivative as being the most active inhibitor. Using EPR spectroscopy, the site of APCT action
in the algal photosynthetic apparatus was determined. It was confirmed that APCT interacted mainly with the D. intermediate,
i.e. with tyrosine radical (TyrD) occurring at the 161st position in D2 protein which is situated on the donor side of photosystem 2. 相似文献
97.
98.
We report on the elaboration of macroporous antimony film electrodes. The strategy to create macroporous electrodes is based on the replication of colloidal crystal templates. These electrodes of controlled porosity show an increased internal electroactive area and a significantly improved electrochemical performance. The application of this novel electrochemical sensor for the sensitive quantification of traces of heavy metals has been demonstrated in combination with differential pulse anodic stripping voltammetry in model solutions. 相似文献
99.
Jan Andres Tom Fürst Karel Pastor 《Journal of Mathematical Analysis and Applications》2008,340(2):1132-1144
A full analogy of the celebrated Sharkovsky cycle coexistence theorem is established for lower semicontinuous (multivalued) maps on metrizable linear continua. This result is further extended to triangular maps. 相似文献
100.