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  • Author or Editor: Z Hegedűs x
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Abstract  

Solid state reactions at 925°C between the high-T c ceramic superconductor YBa2Cu3O7−δ and La2O3 and SrCO3, respectively, mixed in various molar ratiosr=MeOn/YBa2Cu3O7−δ, were studied using X-ray powder diffraction and scanning electron microscopy. The reaction between YBa2Cu3O7−δ and La2O3 yielded (La1−xBax)2CuO4−δ, withx≈0.075−0.10. La2−xBa1+xCu2O6−δ, withx≈0.2−0.25 and La-doped (Y1−xLax)2BaCuO5, withx≈0.10−0.15. Forr=3.0, Y-doped La2BaCuO5 resulted also. The reaction between YBa2Cu3O7−δ and SrCO3 yielded (Sr1−zBaz)2CuO3, withz≈0.1, Y2(Ba1−zSrz)CuO5, withz=0.1−0.15, and a nonsuperconducting compound with an approximate composition of Y(Ba0.5Sr0.5)5Cu3.5O10±δ. At values ofr≤2.0, unsubstituted YBa2Cu3O7−delta was found in the reaction products.

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Six wheat varieties representing different genotypes were tested under exposed and protected conditions in a three year herbicide provocation field trial at Nagygombos, Hungary. Three types of herbicide treatments (fluroxipir, bromoxynil and dicamba ai.) were applied in comparison with untreated and mechanical treated controls. Weed populations were sorted into two major groups according to the level of their occurrence. The result of experimental treatments were evaluated and  weed tolerance of varieties was determined. The magnitude of weed populations has shown significant differences. All weed control treatments, including chemical and mechanical applications, had an influence on weed development. Herbicide treatments had about fifty per cent, while mechanical applications had a nearly hundred per cent effect concerning weed reduction. The latter can be considered as a level of total weed extinction. High weed canopies were observed in the case of untreated controls only. Wheat cultivars have shown a variety specific yield response. The results obtained suggest varietal differences concerning weed tolerance. The extent of yield losses between wheat cultivars ranged from 4 to 18 per cent of grain yield. In the trial Martonvásári 19 and Martonvásári 21 wheat varieties were proven to have the best weed tolerance abilities. 

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The milling and baking quality of wheat is mainly determined by the genetic basis, but may also be influenced by management techniques. Series of winter wheat varieties were examined under identical agronomic conditions in the experimental years of 1996-2001. Weed control, the rate and application time of nitrogen top dressing, the use of insecticide and fungicide and the climate of the production year were evaluated as main factors. In the present study two major characteristics: the protein and gluten content of grain samples, were examined. The effect of nitrogen fertilization proved to have the strongest impact on both quality indexes. no significant quality differences were induced by the various means of weed control. Plant protection treatments had a rather diverse effect on the contents of the protein and gluten in certain years. The protein and gluten values were correlated in all the experimental treatments, but the level of the correlation showed considerable variation. The effect of crop year proved to be the strongest, followed by fertilization, from among the quality-determining factors. The protein versus gluten correlation was also found to be the closest in the case of nitrogen top dressing applications.

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Abstract  

The determination of the titanium content of bauxite samples of various origin was studied by thermal neutron activation and X-ray analysis. A252Cf-fission neutron source and a Ge(Li) detector as well as a3H exciting source and a Si(Li) detector were used in the investigations. Within equal measuring times and with a sample weight of 8 g the sensitivity of the activation method is 0.35 w% Ti with an absolute statistical error less than 10%, while that of the X-ray method is 0.06 w% Ti and the absolute statistical error does not exceed 5%.

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Functional role of calcium-activated potassium (KCA) channels on the basal and agonist-elevated arterial tones was investigated in isolated rabbit aorta, porcine and canine coronary arteries as well as in human internal mammary artery. The vascular tones enhanced by contractile agents were increased further by preincubation of these conduit blood vessels with selective (charybdotoxin or iberiotoxin) or non-selective (tetraethylammonium) inhibitors of KCA channels. The basal tone (without an agonist) was increased only in the canine coronary artery. The results indicate a feed-back regulatory role of KCA channels counteracting the vasospasm of conduit arteries.

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