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91.
92.
Chemical oxygen demands of fourteen nitrogenous compounds were determined by the dichromate method. Only pyridine and its derivatives were resistant to oxidation. Heterocyclic compounds containing one atom of nitrogen in a molecule, e.g. quinoline, pyrrole, proline, and indole were 90–100 per cent oxidized. Nitrogen is split off these compounds as NH3. Heterocyclic compounds containing two or more atoms of nitrogen in a molecule are also easily oxidized. However, only a part of the nitrogen is split off as NH3. On the basis of the results obtained it is possible to make the following generalization: nitrogen in amino groups is split off mostly as NH3; quinoline, pyrrole, pyrrolidine, and indole nitrogen is split off as NH3; from imidazole and pyrimidine rings, one atom of nitrogen is split off as NH3 and one as N2; from the purine configuration, two atoms of nitrogen are split off as NH3 and two atoms as N2; from isoalloxazine, three atoms of nitrogen are split off as NH3 and one as N2. 相似文献
93.
The chlorine and oxygen overpotential in dependence on the current density i (A cm?2) and on the temperature in the range of 15–75°C was measured at γ-MnO2 and β-PbO2 electrodes in concentrated water solutions of sodium chloride and perchlorate. From the measured values the experimental activation energy in dependence on overpotential was calculated and, for the temperature of 25°C, the constants of Tafel's equation (a,b) (α, io respectively) were evaluated. 相似文献
94.
The Isw2p-Itc1p chromatin remodelling complex of Saccharomyces cerevisiae is a member of the ISWI class of ATPases with a nucleosome spacing activity, involved in regulation of expression of a broad spectrum of genes. Its absence causes derepression of a-specific genes and aberrant morphology in alpha-mating type cells. We report here that the deletion of the ISW2 gene in the originally non-invasive BY strain induces mating type-specific invasive growth strongly affected by nitrogen starvation. Although the Flo11 protein was postulated to be critical for haploid invasive growth, we showed that the invasive growth caused by the isw2 and itc1 deletions in alpha-mating type cells was Flo11p-independent. This type of invasive growth was proved to be a consequence of the activation of the pheromone response pathway. Our results suggest that Isw2 and Itc1 proteins do not have the same impact on the described phenomenon. 相似文献
95.
Separation of H(2)SO(4) + CuSO(4) mixture by diffusion dialysis 总被引:1,自引:0,他引:1
Diffusion dialysis of aqueous solution of H(2)SO(4) + CuSO(4) has been investigated in a two-compartment cell with an anion-exchange membrane Neosepta-AFN. The experiments have proved that sulfuric acid permeates well through the membrane used, while cupric sulfate is efficiently rejected. This operation is very effective at high acid concentrations and low concentrations of cupric sulfate. Furthermore, it has been found that even at the highest concentration of CuSO(4), the rejection coefficient is higher than 0.965. The flux of CuSO(4) calculated from the time dependences of the CuSO(4) concentration is negatively influenced by increasing acid concentration. 相似文献
96.
Martin?MarciniszynEmail author Angelika?Steger Andreas?Wei?l 《Informatik-Spektrum》2004,27(3):248-254
97.
The fracture behaviour of single crystal silicon (SCSi) microstructures is analysed based on microme-chanical torsional and
tensile experiments. The uniaxial testpieces are characterised by the presence of sharp not-ches at the gauge length extremities.
The critical loading conditions are reproduced in a finite element model in order to identify the analogies of the failure
conditions in tension and torsion. The stress field in the vicinity of the notch tip (were cracks originate) is analyzed,
and fracture mechanics parameters are determined. In the finite element model a crack, reproducing the failure process observed
in the experiments, is included. The crack area is incrementally increased and the energy release rate for the critical loading
conditions in tension and torsion is calculated. Based on these results a failure criterion is formulated along with a procedure
for the mechanical integrity analysis of SCSi microstructures of arbitrary shape and loading conditions. 相似文献
98.
Two criticality dosimetry systems were tested by Czech participants during the intercomparison held in Valduc, France, June 2002. The first consisted of the thermoluminescent detectors (TLDs) (Al-P glasses) and Si-diodes as passive neutron dosemeters. Second, it was studied to what extent the individual dosemeters used in the Czech routine personal dosimetry service can give a reliable estimation of criticality accident exposure. It was found that the first system furnishes quite reliable estimation of accidental doses. For routine individual dosimetry system, no important problems were encountered in the case of photon dosemeters (TLDs, film badge). For etched track detectors in contact with the 232Th or 235U-Al alloy, the track density saturation for the spark counting method limits the upper dose at approximately 1 Gy for neutrons with the energy >1 MeV. 相似文献
99.
In this paper the one-way P automata with priorities are introduced. Such automata are P systems where the membranes are only allowed to consume objects from parent membranes, under the given conditions. The result of computation of these systems is the set of multiset sequences consumed by skin membrane into the system. The rules associated in some order with each membrane cannot modify any objects, they can only move them through membrane. We show that P automata with priorities and two membranes can accept every recursively enumerated language. 相似文献
100.
The results of DTA analysis of amorphous arsenic in combination with electron microscopical study of the samples through the whole temperature range reveal that no changes of the initial state of the sample occur on heating up to crystallization temperature. Close above this temperature the spontaneous crystallization starts. It differs markedly from the case of glassy materials, like As2Te3, in which case at temperatures as low as the transition region Tg the crystallization nuclei of geometrically defined shapes appear and grow into crystalline grains on further heating. 相似文献