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111.
J. Kousal M. Klíma J. Janča V. Kapicka P. Slavíček A. Brablec P. Sulovský 《Czechoslovak Journal of Physics》2000,50(3):409
Plasma pencil is a device which can produce plasma jet at atmospheric pressure and low power (10–200 W) from DC to HF. The jet character of the plasma makes this device very efficient in aimed local (1 – 102 mm2) modifications of surfaces. Great variability in possible power sources allow to achieve a broad range of effects on materials. We have tested bipolar discharges with a metal object and a unipolar HF discharge to burn the glazing on ceramics. Both technologies could be prospective. 相似文献
112.
The oxidation of metal sulphides and sulphide concentrates was studied by means of DTA, TG and DTG curves. The behaviour of
ZnS, CdS, GaS, Tl2S, Sb2S3 and Sb2S5 during thermal treatment in an oxidizing medium was investigated. The properties of these sulphides were compared and conclusions
were drawn about their probable oxidation reactions and the kind of end-products obtained. The characteristic temperatures
of the studied sulphides were determined on the basis of curves (DTA). The values obtained were used to compare the behaviour
of the sulphides during the oxidation process in a fluid bed. The results can be used to improve the technological and economic
indices in the industrial production of zinc.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
113.
Laser ablation generation of clusters from As‐Te mixtures,As‐Te glass nano‐layers and from Au‐As‐Te nano‐composites. Quadrupole ion trap time‐of‐flight mass spectrometry
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114.
Said El‐Kurdi Abdal‐Azim Al‐Terkawi Bernd M. Schmidt Anton Dimitrov Dr. Konrad Seppelt Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(2):595-599
WF6 reacts with phosphines R3P forming 1:1 compounds. With R=P(CH3)3 the coordination around the tungsten atom is capped trigonal prismatic, with R=P(CH3)2C6H5 the coordination is capped octahedral, as established by single‐crystal structure determinations: [(CH3)3P? WF6]: a=752.5(21), b=945.7(24), c=629.8(18) pm. β=110.36(13)°, space group Cm, Z=2; [(CH3)2(C6H5)P? WF6]: a=762.2(2), b=1123.5(2), c=2647.5(6) pm, space group Pbca, Z=8. [(CF3CH2)2N? WF5] reacts smoothly with P(C6H5)3 forming known P(C6H5)3(F)2 and [(CF3CH2)2N? WF4? P(C6H5)3], a stable, green, molecular species, identified among other methods with an crystal structure determination: a=914.9(1), b=956.0(1), c=1449.8(2) pm, α=7.642(4), β=81.648(3), γ=81.519°, space group P$\bar 1$ , Z=2. 相似文献
115.
Mekenyan O Dimitrov S Dimitrova N Dimitrova G Pavlov T Chankov G Kotov S Vasilev K Vasilev R 《SAR and QSAR in environmental research》2006,17(1):107-120
The role of metabolism in prioritising chemicals according to their potential adverse health effects is extremely important given the fact that innocuous parents can be transformed into toxic metabolites. Our recent efforts in simulating metabolic activation of chemicals are reviewed in this work. The application of metabolic simulators to predict biodegradation (microbial degradation pathways), bioaccumulation (fish liver metabolism), skin sensitisation (skin metabolism), mutagenicity (rat liver S-9 metabolism) are discussed. The ability of OASIS approach to predict metabolism (toxicokinetics) and toxicity (toxicodynamics) of chemicals resulting from their metabolic activation in a single modelling platform is an important advantage of the method. It allows prioritisation of chemicals due to predicted toxicity of their metabolites. 相似文献
116.
117.
Wei Q Seward GK Hill PA Patton B Dimitrov IE Kuzma NN Dmochowski IJ 《Journal of the American Chemical Society》2006,128(40):13274-13283
Xenon-129 biosensors offer an attractive alternative to conventional MRI contrast agents due to the chemical shift sensitivity and large nuclear magnetic signal of hyperpolarized (129)Xe. Here, we report the first enzyme-responsive (129)Xe NMR biosensor. This compound was synthesized in 13 steps by attaching the consensus peptide substrate for matrix metalloproteinase-7 (MMP-7), an enzyme that is upregulated in many cancers, to the xenon-binding organic cage, cryptophane-A. The final coupling step was achieved on solid support in 80-92% yield via a copper (I)-catalyzed [3+2] cycloaddition. In vitro enzymatic cleavage assays were monitored by HPLC and fluorescence spectroscopy. The biosensor was determined to be an excellent substrate for MMP-7 (K(M) = 43 microM, V(max) = 1.3 x 10(-)(8) M s(-1), k(cat)/K(M) = 7,200 M(-1) s(-1)). Enzymatic cleavage of the tryptophan-containing peptide led to a dramatic decrease in Trp fluorescence, lambda(max) = 358 nm. Stern-Volmer analysis gave an association constant of 9000 +/- 1,000 M(-1) at 298 K between the cage and Trp-containing hexapeptide under enzymatic assay conditions. Most promisingly, (129)Xe NMR spectroscopy distinguished between the intact and cleaved biosensors with a 0.5 ppm difference in chemical shift. This difference most likely reflected a change in the electrostatic environment of (129)Xe, caused by the cleavage of three positively charged residues from the C-terminus. This work provides guidelines for the design and application of new enzyme-responsive (129)Xe NMR biosensors. 相似文献
118.
Whereas liquid CCl3F reacts with solid AlCl3 exothermically under chlorine-fluorine-exchange already above -20 degrees C, no reaction takes place between CCl3F and the pyridine complexes of AlCl3 (AlCl3.Py, AlCl3.2Py, or AlCl3.3Py) up to 100 degrees C. The desired chlorine by fluorine substitution on the monomer AlCl3-pyridine adducts occurs, however, easily using Me3SiF as fluorinating agent. By reacting AlCl3.3Py with Me3SiF (even up to 10-fold stoichiometric excess) in pyridine as a solvent, only two of the three Cl atoms can be substituted by fluorine, leading in good yield to the new "mixed aluminum halide", AlF2Cl.4Py. Actually, it represents the first example of a stable solid donor-acceptor adduct of an aluminum-III halide with two different halogens of defined stoichiometry. It was characterized by multinuclear solid-state NMR (27Al and 19F), IR spectroscopy, as well as single-crystal structure analysis. The new compound has an ionic solid-state structure with helical trans-octahedral [(Py)4AlF2]+ cations and isolated Cl- anions. The comparison of its 27Al MAS solid-state NMR spectra with those of a compound bearing the analogous [(Py)4AlCl2]+ cation reveals an extreme increase in the quadrupolar coupling constants, from 0.24 MHz in case of the chlorine cation to about 16 MHz in case of the new [(Py)4AlF2]+ cation. 相似文献
119.
Hartmann M Maeda Y Keshelashvili I Koch HR Mikirtytchiants S Barsov S Borgs W Büscher M Dimitrov VI Dymov S Hejny V Kleber V Koptev V Kulessa P Mersmann T Merzliakov S Mussgiller A Nekipelov M Nioradze M Ohm H Pysz K Schleichert R Stein HJ Ströher H Watzlawik KH Wüstner P 《Physical review letters》2006,96(24):242301
The pp-->ppphi reaction has been studied at the Cooler Synchrotron COSY-Jülich, using the internal beam and ANKE facility. Total cross sections have been determined at three excess energies epsilon near the production threshold. The differential cross section closest to threshold at epsilon=18.5 MeV exhibits a clear S wave dominance as well as a noticeable effect due to the proton-proton final-state interaction. Taken together with data for ppomega production, a significant enhancement of the phi/omega ratio of a factor 8 is found compared to predictions based on the Okubo-Zweig-Iizuka rule. 相似文献
120.
It is shown for the first time that reflection ellipsometry may be an effective method of establishing a correlation between
the main parameters of gas-sensitive layers and their optical characteristics, suitable for rapid monitoring. This can advance
the capability of predicting the properties of a material from its preparation conditions and consequently can reduce the
optimization cycle time and thus lower the cost of a technology.
Zh. Tekh. Fiz. 69, 129–130 (April 1999) 相似文献