一类四阶非自治微分方程解的有界和一致有界性

获得了一个四阶非线性微分方程的所有解是有界和一致有界的充分条件。     

The anharmonic character of Tg and Tm transition

The idea of anharmonic oscillations has been extended to explain the glass transition or melting point. All ideas of free volume, vacancy transport, etc., have been respected but are treated as minor phenomena relative to harmonic-anharmonic vibration transition. A simple model of coupled oscillators is studied. It is shown that coupled anharmonic oscillators can produce vibrations on entirely different levels of amplitudes, which explains the highly different coefficients of thermal expansion and c_p values for solid and liquid states. At higher temperatures, for polymers in the rubber-like zone, the theory of anharmonic coupled oscillators brings certain justification for the theories of De Gennes, Doi and Edwards or Rouse. The solid-liquid transition seems to be connected on microlevel mainly with the enlargement of vibrational amplitudes of monomer or dimer units in polymer chain as the temperature increases.     

Der Einfluss der Plastischen Verformung durch Kaltwalzen auf die Koerzitivkraft

Zusammenfassung Es werden die Ergebnisse der Messungen der Koerzitivkraft von Eisen, Nickel und einiger Fe-Ni-Legierungen in Abhängigkeit von der plastischen Verformung durch Kaltwalzen angegeben. Gemessen wurde in Richtung parallel und senkrecht zur Walzrichtung. Die Ergebnisse werden insbesondere vom Gesichtspunkt des Einflusses der Versetzungen und der einachsigen induzierten Anisotropie diskutiert.

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Für die wertvollen Diskussionen und das Durchlesen der Arbeit danken wir den Kollegen J. Kaczér und V. Janovec, für die wirkungsvolle Hilfe bei den Messungen Koll. J. Grolmus.     

Einige Neue N,S-Substituierte 2-Nitrodienverbindungen Aus Reaktionen Von Mono(p-fluorarylthio)substituierten Dienen Mit Aminen

2-Nitrodiene compound 1 was stirred with p-fluorothiophenol for a long time and compound 3 was obtained. Compound 1 gave bis(thio)substituted 2-nitrodiene compound 4 and tris(thio)substituted compound 5 with 2 moles of p-fluorothiophenol in the presence of NaOH in ethanol. The compounds 9a–g have been prepared from 8a–g and 3. Compound 7 was obtained from the reaction of mono(thio)substituted 2-nitrodiene with morpholine. Compound 3 gives 11a–d in the reaction with piperidines in CH₂Cl₂ (or ether). Compound 13a–b have been obtained from the reaction of compound 3 with primary amines 12a–b. Compound 3 gives 15 and 16 in the reaction with 2,5-dimethylpiperazine in CH₂Cl₂.

     

Second generation of primaquine ureas and bis-ureas as potential antimycobacterial agents

Molecular Diversity - Here, we describe design and synthesis of twelve novel compounds bearing primaquine motif and hydroxy- or halogenamine linked by an urea or bis-urea spacer. Preparation of...     

A new tool for the post-process modification of chips by nanostructures for chemical sensing

The tool is built up on moving plates driven by step-motors for precise location of sensors chip on the wafer to perform post-processing of the chip. The tool can make chemical or electrochemical deposition and etching for the chip modification after wafer processing. Each chip on the wafer can be modified with different process. The deposition from solutions and wet etching is controlled by a flow-system and power source if it is necessary. Techniques for ordered nanostructures creation using the tool were also developed. The tool helps to improve properties of microsensors fabricated on the chip by thin-film and semiconductor technology.     

Absolute detector calibration using twin beams

A method for the determination of absolute quantum detection efficiency is suggested based on the measurement of photocount statistics of twin beams. The measured histograms of joint signal-idler photocount statistics allow us to eliminate an additional noise superimposed on an ideal calibration field composed of only photon pairs. This makes the method superior above other approaches presently used. Twin beams are described using a paired variant of quantum superposition of signal and noise.