An activation analytical method is described for the determination of small concentrations of Ga in tungsten. The samples
are irradiated with reactor neutrons and dissolved in a hot chamber using a remote manipulator. After the adjustment of thepH, Ga is extracted in the form of its cupferron complex in chloroform solution. The organic phase is washed and, depending
on the efficiency of the separation from tunsgten, a Ge(Li) semiconductor detector, or a NaI(Tl) scintillation counter is
used for the gamma-spectrometric evaluation.
The sensitivity of the method for a sample of 2 g was found to be 10−9 g of Ga/g of W. The determination can be carried out, and is well reproducible, with an accuracy of ±30%.
Investigations have been made concerning the determination of special contaminants (e.g. oxygen, boron) in the surface layers
or epitaxially grown layers of semi-conductor crystals. These contaminants are insensitive to the conventional (n, γ) analysis
and for their activation charged particles (e.g. t, α) from nuclear reactions induced by the capture of reactor neutrons are
used. The specific particle yield from such reactions, e.g.6Li(n,t)α, was studied. The optimum conditions for the producing of activating layers (containing Li) and their optimum contact
with the sample under investigation are discussed. Considering the so-called activation depth, a method was developed for
the appropriate removal of the activated layer and the elements to be determined are subsequently separated from the semiconductor
matrix by a fast chemical procedure. The combined activation cross sections measured on standard samples are given for different
compositions and species of activating layers.
The paper gives a short panoramic historical survey about the main activities of the Hungarian phytosociology, their chief protagonists, the fundamental role of professor Rezső Soó in the creation and development of the phytosociological school of Debrecen established by him in the Botanical Department of the University of Debrecen, which is celebrating the 80 anniversary of its existence and has played a determinant role in the Hungarian botany.
A new rock-heath association (Helleboro odori-Spiraeetum mediae Borhidi, Morschhauser et Salamon-Albert ass. nova) was recently discovered in Central Mecsek Mts which is described and discussed by the authors in the article. It represents a special skirt vegetation developing in contact with the chestnut oakwood on the edge of rocky ridges. It differs from the subcontinental rock-heath (Waldsteinio-Spiraeetum mediae Zólyomi 1936) living in the North Hungarian Middle Range by having a set of Balcanian, Pontic and sub-Mediterranean species occurring in both the shrub and herb layers. Higher indicator values of certain ecological factors, like temperature (T) and soil reaction (R) are indicating the special basiphilous and warm character of the habitat of the new community. SBT-spectrum shows the well-balanced state, the average values of VAL indicate the natural state of the community.
rich meadows have been introduced in the last couple of years as
in Hungary, but have not been confirmed by studying sampling plots. It is a rare, edaphic, semi-natural edge vegetation of subcontinental climatic zone on alluvial surfaces. In our study characteristic species composition and vegetation structure integrated with ecological considerations are described. Analyses were carried out by phytosociological tables, chorographical types, relative ecological indicator values and social behaviour types. Most of the vegetation phenomena indicated in general descriptions and overviews are supported. This community is species rich, 3-layered vegetation with a multi-dominating species pool. High proportions of constant and accidental species, Molinietalia and indifferent coenological elements, Eurasian and European and sub-Mediterranean distribution types, competitors and specialists have large importance in this vegetation structure. Its life form strategy is based on the balance between hemicryptophytes and geophytes. Using ecological indicator values, habitat characteristics and phytogeographical status of the association had been revealed.
The application of pulse radiolysis to the measurement of rates of reaction of aromatic and olefinic radical anions in organic solvents is discussed, emphasis being placed on the problem of reaction of the radical anion with the radiolytically-generated-counter ion. Some previous experiments of the authors that utilised tetrahydridoaluminate salts to scavenge the counter ion are reviewed. Some new data on the rates of electron transfer from aromatic-radical anions to some substituted styrenes are presented and experiments aimed at using organic amides as solvents for these studies are described.
Green fodder mixture trials were carried out with GK Impala, a winter hardy, fall sown oat variety registered in 2005 intercropped either with winter vetch or winter pea in a crop year when the spring was dry (2003) and in another one (2004) when the precipitation was optimal in spring. The two components of mixtures were sown 50% each. A four-replicate randomised complete block design was used with 50 m2 plots. The results were compared to the mixtures of spring oats and vetch; and spring oats and pea, respectively. The green matter of fall sown crops was cut by scythe late May, whereas that of spring crops early June.Data demonstrate that the green forage yield and protein production of fall sown oats as a monocrop and intercropped with vetch was higher than those of spring types. Green matter and dry matter yield varied with season, and were more advantageous in the year 2004, when there was more precipitation. The crude protein content of winter vetch and the crude protein production of the mixture fall sown oats + winter vetch were the highest. The mixtures with winter or spring pea yielded less green matter and, as a matter of fact, less crude protein. The fodder mixtures cereals — legumes are conventionally and widely used as feed for livestock in North-America, and the results of our two-year experiment suggest that their use should be intensified in Hungary as well, mainly in the provisional feeding of ruminants. To date, oat varieties with reliable winter hardiness are offered for fall sowing.
The aim of the present study was to evaluate the effect of high hydrostatic pressure (HHP) processing (at 450 or 600 MPa for 300 s) on microbial quality as well as on organoleptic properties of fish salad with mayonnaise during 26 days of storage at 5 and 10 °C. The salad contained diced smoked trout fish, mayonnaise, and different kinds of spices. These freshly made salads usually have only a couple of days of shelf life. The HHP treatment basically did not affect the physical and organoleptic characteristics of the fish salad with mayonnaise. At both storage temperatures, the HHP treated samples showed enhanced safety and increased shelf-life up to 3 weeks.
In the experiments pork loin and beef sirloin were treated by pressures of 100 to 600 MPa by 100 MPa steps for 5 min. Colour changes of samples and the changes of proteins were investigated. The latter were examined with isoelectric focusing and SDS polyacrylamide gel electrophoresis. We found that myoglobin behaved completely differently in case of the two different species. Myoglobin has mostly lost its native state at 300 MPa pressure in case of pork, but the beef myoglobin could remain native even up to 500 MPa. The treatment at 300 MPa or higher pressure values caused almost complete aggregation and denaturation in case of pork and beef proteins. The results of SDS-PAGE and the colour measurement confirmed this finding.