Magnetic ordering in DyNi2Si2 andDyNi2Ge2 intermetallics studied by161Dy Mössbauer spectroscopy

The¹⁶¹Dy Mössbauer spectra of DyNi₂Si₂ andDyNi₂Ge₂ have been measured at temperatures between 4.2 and22 K. Temperature dependences of spectrum and-ray transmission rate at zero velocity as well as magnetic susceptibility measurements indicate clearly that anti-ferromagnetic orderings occur atT _N=7 K in DyNi₂Si₂ and9 K in DyNi₂Ge₂. Though the spectrum of DyNi₂Si₂ is interpreted approximately by a single set of hyperfine parameters, that of DyNi₂Ge₂ exhibits broadening of absorption lines which originates from distributed hyperfine parameters. The small values of hyperfine field, 707 MHz at 2.9 K in DyNi₂Si₂ and 765 MHz at 3.0 K in DyNi₂Ge₂ are attributable to the crystalline electric field interaction.     

Computational complexity to verify the unstability of effectivity function

Ann-person game is considered where each player has a preference order over a finite setA of possible alternatives and a rule for social choice is given in the form of an effectivity functionE. The effectivity function is called stable if for any combination of individual preference orders there exists a subset ofA called a core such that any alternative in the core cannot be dominated by such individual preferences. It has been shown by Keiding (1985) that the effectivity functionE is stable if and only ifE does not generate any Cycle. This paper is concerned with the computational complexity of the problem (CYCLE) for determining whether or not a given effectivity function has a Cycle, We show that a familiar NPC problem SATISFIABILITY can be transformed into CYCLE through a polynomial time procedure. This, combined with the fact that CYCLE is an NP problem, implies NP-completeness of CYCLE, and therefore that of verifying the unstability of the effectivity function, thereby formally proving a previously unanswered conjecture.     

Asymptotic Properties of Generalized Feynman–Kac Functionals

Let ( ) be a regular Dirichlet form on L2(X;m) and {Px}x X the Hunt process generated by ( ). Let be a signed 'smooth measure' associated with ( ) and At the continuous additive functional corresponding to the measure . Under some conditions on ( ) and , we shall prove that

New Triterpenes from Siyekucai （Ixeris chinensis）

The whole plant of Ixeris chinensis Nakai (Compositae)1,2 was used as a folk medicine inChina for the treatment of bronchitis, pneumonia, pharyngitis, dysentery, and poisonousindigestion on the basis of its antifebrile, and analgesic effects. In previous …     

Acoustically induced light gyration in nickel nanoparticles

Circularly polarized acoustically induced light gyration (AILG) in nickel nanoparticles (NiNPs) attached to indium tin oxide (ITO) substrates was observed to be enhanced by nanosecond UV laser excitation at a wavelength in the surface plasmon resonance region. The AILG was observed during exposure to two acoustical waves with frequencies of 2 and 4 MHz and power densities of up to 5 W/cm². The maximum value of the AILG observed for NiNPs of average size ca. 8.7 nm, attached to an ITO substrate was about 2.8°/mm without UV-light illumination. Additional irradiation by 5 ns pulse UV laser light (λ: 337 nm) at the surface plasmon resonance region was found to favour the additional enhancement of the AILG up to 11°/mm. The effect was optimized at a temperature of 120 K. This increase was not observed when the size of NiNPs was 16.8 nm.     

Addition of α-hydroxyalkylferrocenes to electrochemically oxidized poly(aniline)

A series of α-hydroxyalkylferrocenes (ferrocenemethanol [FcCH₂OH], α-hydroxyethylferrocene, and 1,1′-ferrocenedimethanol) have been shown to incorporate into highly oxidized films of poly(aniline) [PAn]. Surface immobilization is readily evident in cyclic voltammetric studies by the rapid growth of a pair of sharp redox waves at E_1/2=0.455 V versus SCE in the case of FcCH₂OH. A general mechanism for the attack of α-hydroxyalkylferrocenes on oxidized PAn is inferred from the electrochemical data.