1,361 research outputs found
Incommensurate interactions and non-conventional spin-Peierls transition in TiOBr
Temperature-dependent x-ray diffraction of the low-dimensional spin 1/2
quantum magnet TiOBr shows that the phase transition at T_{c2} = 47.1 (4) K
corresponds to the development of an incommensurate superstructure. Below
T_{c1} = 26.8 \pm 0.3 K the incommensurate modulation locks in into a two-fold
superstructure similar to the low-temperature spin-Peierls state of TiOCl.
Frustration between intra- and interchain interations within the spin-Peierls
scenario, and competition between two-dimensional magnetic order and
one-dimensional spin-Peierls order are discussed as possible sources of the
incommensurability.Comment: 5 pages including 3 figures and 1 tabl
Design solution for hoists
Bakalárska práca sa zaoberá rozdelenĂm a popisom funkcie, princĂpu ÄŤinnosti, vlastnostĂ a charakteristĂk pouĹľĂvanĂ˝ch konštrukÄŤnĂ˝ch riešenĂ a jednotlivĂ˝ch súčastĂ výťahov. Na koncepÄŤnĂ˝ch riešeniach je vykonanĂ© zhodnotenie pouĹľiteĹľnosti, vhodnosti a účelnosti rĂ´znych alternatĂv i s vĂ˝berom najvhodnejšĂch riešenĂ podĹľa zadania.This thesis deals with classification, description of service, properties and characteristics of used design solutions and individual components of hoists. The most common conceptual solutions are evaluated from the point of usability and suitability with the choice of the most suitable solutions according to given assignment.
A mennyiségdetekció feladványa : két rivális elmélet ütköztetése
Tárgyak mennyisĂ©gĂ©nek megállapĂtásakor 4-ig az emberek viszonylag gyorsan számolnak (szubitizálnak), mĂg 4 fölött relatĂve lelassulnak (számolás). A mennyisĂ©gek Ă©szlelĂ©sĂ©ben tapasztalhatĂł mintázatkĂĽlönbsĂ©g magyarázatában uralkodĂł kĂ©tfĂ©le megközelĂtĂ©st teszteltĂĽk. Az analĂłg mennyisĂ©gi reprezentáciĂł (vagy mentális számegyenes) kĂ©pviselĹ‘i szerint a mennyisĂ©gi reprezentáciĂłk (WEBER törvĂ©nyĂ©nek megfelelĹ‘) jellemzĹ‘i miatt könnyebb a 4 alatti számok diszkrimináciĂłja, ugyanis itt a számok között a relatĂv kĂĽlönbsĂ©g viszonylag nagy, ám 4 fölött a kĂĽlönbsĂ©g csökken Ă©s ennek következtĂ©ben a mennyisĂ©g felismerĂ©se több idĹ‘t vesz igĂ©nybe. A másik megközelĂtĂ©s szerint a tárgy alapĂş vizuális figyelmi rendszer (prekonceptuális) összetevĹ‘i okozzák a szubitizáciĂł Ă©s a számolás (reakciĂłidĹ‘kben) kirajzolĂłdĂł kĂĽlönbsĂ©gĂ©t: nĂ©gy alatt ugyanis pusztán a foglalt tárgyfájlokat (vagy vizuális indexeket) kell megszámolni, mĂg nĂ©gy fölött a tárgyfájlok más objektumokra valĂł áthelyezĂ©se plusz idĹ‘t igĂ©nyel. Vizsgálatunkban a mentális számegyenes egyĂ©ni kĂĽlönbsĂ©geit, a vizuális index egyĂ©ni mutatĂłszámait Ă©s a szubitizáciĂł terjedelmĂ©t korreláltattuk egymással. Az eredmĂ©nyek szerint a mentális számegyenes jĂłsolja be a szubitizálciĂł terjedelmĂ©t, mĂg a vizuális rendszer általában a pontok számolásának sebessĂ©gĂ©t. There are two explanations accounting for the phenomena of subitizing (counting objects up to 4 is relatively fast, but above 4 it gets slower). Exponents of the analog magnitude system theory advocate that in case of numbers smaller than 4, discrimination is easy (according to Weber's Law) because there are relatively great differences in quantity between these numbers. Rising above 4, decreasing differences eventuate expanding quantity detection times. From another viewpoint different reaction times are caused by the preconceptual features of an object based visual attention system: below 4 it is enough to count the occupied object files, while above 4, transfering object files onto other elements requires more time. In our experiment individual differences of subitizing are correlated with indexes of mental magnitude sensitivity and object file capacity. The index of subitization should show stronger correlation with the background system of the phenomenon itself. Our results point to a high correlation between the accuracy of subitizing and mental magnitude sensitivity. On the other hand we also found high correlation between subitizing response times and sensitivity of the visual attention system. These results let us have a more accurate picture of the background processes of subitizing
H2 activation using the first 1:1:1 hetero-tri(aryl)borane
The novel 1:1:1 hetero-tri(aryl)borane (pentafluorophenyl){3,5-bis(trifluoromethyl)phenyl}(pentachlorophenyl)borane has been synthesised and structurally characterised. This has been show to act as the Lewis acidic component in FLPs for the heterolytic cleavage of H2 with three Lewis bases
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