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101.
Gianni Bosi Juan Carlos Candeal Esteban Induráin Esteban Oloriz Margarita Zudaire 《Order》2001,18(2):171-190
In the framework of the analysis of orderings whose associated indifference relation is not necessarily transitive, we study the structure of an interval order and its representability through a pair of real-valued functions. We obtain a list of characterizations of the existence of a representation, showing that the three main techniques that have been used in the literature to achieve numerical representations of interval orders are indeed equivalent. 相似文献
102.
Margarita A. Deneva Pepa I. Uzunova Marin N. Nenchev 《Optical and Quantum Electronics》2007,39(3):193-212
We report (theory, experimental check) an improved approach for generation of a tunable, subnanosecond pulse (0.1–0.4 ns),
based on a single pulsation (“spike”) separation from the transient oscillations in a dye laser with active mirror (AMIR).
A pumping by 20–50 ns pulses from Q-switched Nd:YAG laser is considered. The separation is in original, two-spectral selective
channels cavity, where the forced by AMIR quenched generation at one of the wavelength stops initially started spiking generation
at the other wavelength after the first spike development. The AMIR quickly starts the quenching generation at a precisely
controlled moment and with necessary intensity thus assuring the desired separation. An advantage is a high reproducibility
of the separation for high (~250%) pump power fluctuations combined with tuning in large range (~20 nm). To obtain such an
operation we form ~1 ns leading front pump pulse by electrooptical temporal cutting of the input pump pulse and use an optical
delay line. This increases also a few times the power in the separated spike (to be ~100 kW). Our approach widens the combinations
of lasers for effective applications of spike separation technique (dye lasers excited by Q-switched solid-state or Cu-vapor
lasers). 相似文献
103.
N. Yu. Svechnikov V. G. Stankevich A. M. Lebedev K. A. Men’shikov B. N. Kolbasov V. V. Kriventsov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2007,1(1):13-17
Homogeneous deuterated hydrocarbon films redeposited from a deuterium plasma discharge inside the T-10 tokamak vacuum chamber are studied using photoluminescence methods; EXAFS, EPR, and IR spectroscopies; and temperature measurements. The photoluminescence excitation spectra of sp 3-sp 2 nanostructures of tokamak films are compared with those of sp 2 nanostructures of C60 fullerite films. The effect of defect states on photoluminescence and its temperature quenching is discussed. It is concluded that the model of temperature luminescence quenching for homogeneous deuterated tokamak films is similar to that for amorphous a-C:H films. 相似文献
104.
The possibility of cyclotron maser cooling of the transverse motion of electrons in a beam with the oblate velocity distribution characteristic of the setups with electron cooling has been analyzed. 相似文献
105.
106.
John C. Graham Xinmin Xu Lonnie Jones Margarita Orticochea 《Journal of polymer science. Part A, Polymer chemistry》1990,28(5):1179-1183
The reaction of bis(ethyl-3-oxo-butanolato-O1,O3)-bis(2-propanolato)titanium(Tyzor DCR and 2-isocyanatoethyl methacrylate (IEM) in refluxing hexane produced a mixture of trimer and polymers of 2-isocyanatoethyl methacrylate which varied considerably from 23 to 92% polymer as the molar ratio of bis(ethyl-3-oxo-butanolato-O1,O3)-bis(2-propanolato)titanium(Tyzor DCR) to 2-isocyanatoethyl methacrylate (IEM) varied from 1:4 to 1:32. The IEM 1-nylon polymer which was soluble in cresol and phenol was characterized by FTIR, 1H-NMR, and 13C-NMR. This analysis also showed that the methacrylate carbon–carbon double bond survived our reaction conditions intact. Based on atomic absorption determination of titanium, the molecular weight of the polymer ranged between 3000 and 4000 g/mol. Thermal gravimetric analysis (TGA) showed the polymer to be stable in air to approximately 250°C. 相似文献
107.
Shaoping Fu David Arráez‐Román Javier A. Menéndez Antonio Segura‐Carretero Alberto Fernández‐Gutiérrez 《Rapid communications in mass spectrometry : RCM》2009,23(1):51-59
In this work, rapid‐resolution liquid chromatography (RRLC) coupled to electrospray ionization time‐of‐flight mass spectrometry (ESI‐TOF‐MS) and ion trap multiple mass spectrometry (IT‐MSn) has been applied to separate and characterize eleven isomers of oleuropein aglycon in fourteen Spanish extra‐virgin olive oils. After the extra‐virgin olive oil sample had been dissolved in hexane and cleaned up by a diol‐bonded phase solid‐phase extraction (SPE) cartridge, the eluting extract was resolved in methanol and analyzed on an Angilent 1200 system with a 4.6 × 150 mm, 1.8 µm Zorbax Eclipse plus C18 column. Mass spectrometry was carried out on a Bruker Daltonics microTOF mass spectrometer and a Bruker Daltonics ion trap mass spectrometer. The characterization of isomers of oleuropein aglycon was based on accurate mass data and the isotope function of characteristic fragment ions in the studied compounds by TOF‐MS, and the fragment ions were further confirmed by IT‐MSn. The fragmentation pathway of oleuropein aglycon was successfully elucidated and all possible transformations among isomers of oleuropein aglycon were suggested. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
108.
短弧氙灯是一种发光强度高,具有从紫外到红外的连续光谱的点光源。本文介绍交流供电的短弧氙灯光源,用两电极短弧氙灯实现三电极短弧氙灯性能的方法。给出了用一个系统满足各种不同发光强度、不同调制波形、不同调制频率的要求,以及在制造和使用过程中应注意的事项。 相似文献
109.
A novel efficient synthetic method for 2,2',3,3'-biphenyltetracarboxylic dianhydride 总被引:1,自引:0,他引:1
A novel approach to the synthesis of 2,2',3,3'-biphenyltetracarboxylic dianhydride is described. The target compound was prepared by a nickel-catalyzed coupling reaction of dimethy 3-chlorophthalate (3-DMCP) for 4 h at 70-80℃, followed by subsequent hydrolysis of tetra-ester in acid solution and dehydration of tetra-acid, with overall yield of 68%. The structures of the products were characterized by IR, 1H NMR and 13C NMR respectively. 相似文献
110.