Color confining parton model for heavy quarkonium decay

We present a gluon jet model for the heavy quarkonium decay incorporating the color neutralization mechanism. Postulating that final hadrons are produced from the color singlet quark-antiquark pair originated each from different gluons, we formulate the production mechanism of hadrons from gluons explicitly. The fragmentation function thus obtained can describe the hadron production not only in the fragmentation region but also in the central one owing to the usage of the Sudakov variables. The result of the average charged multiplicity from Υ(9.46) is in reasonable agreement with the data, in contrast to the naive estimates. Furthermore, the inclusive momentum and multiplicity distributions are discussed.     

PHYTOCHROME SYNTHESIS DURING IMBIBITION IN EMBRYONIC AXES OF Pisum sativum L.*

Abstract— The exact quantity of phytochrome in crude homogenates (2kS) prepared from embryonic axes of Pisum sativum during imbibition at 25°C on 0,2% agar was estimated optically. The problem of the scattering factor was solved by using highly purified phytochrome as an internal standard. The content of phytochrome protein moiety in diluted samples of the crude homogenates of the axes was also determined by an enzyme-linked immunosorbent assay (ELISA). Phytochrome was not detectable either spectropho-tometrically or immunochemically in 2kS of dormant dry axes. Embryonic axes quickly absorbed water during the first1–2 h after the start of imbibition, after which the fresh weight stayed at a constant level for a further 10 h. The content of spectrophotometrically detectable phytochrome increased during imbibition in the dark, reaching about 0.2 μ.g/axis after 12 h. The amount of phytochrome in 2kS of axes in the light was so small that only about 0.05 μg/axis was detected after 12 h. The content of immunochemically detectable phytochrome greatly increased up to ca. 0.5 μg/axis after 12 h of dark incubation. In 2kS of the light-grown axes the content of the phytochrome protein was ca. one fourth lower than in dark-grown axes. We conclude that the appearance and increase of phytochrome in fragments of imbibed embryonic axes were caused by de novo synthesis and that the contents of both photometrically detectable phytochrome and its protein moiety in the light-grown samples were lower than those in the dark throughout the early germination process.     

Polarization memory of luminescence from photo-generated carriers in aSixC1−x:H (x∼0.2)

Photoluminescence of aSi_xC_1?x:H (x～0.2) is studied with a particular interest on the localization of carriers. Taking the polarization memory of luminescence as a probe, we clarify the localized character of photo-generated carriers as functions of excitation photon energy, emitted photon energy, temperature and time. The picosecond time-resolved measurement of the polarization memory is shown useful to study dynamical relaxation processes of carriers in disordered systems.     

Flourescence lifetimes anf excitation spectra of the jet-cooled HNO radical

The new nozzle assembly using Hg-photosensitized reaction has been developed to obtained a jet-cooled radical beam. This technique was applied to produce a HNO radical beam. Laser-induced flourescence excitation spectra were obtained for the $\text{A}$¹A″ — $\text{X}$¹A′ system. Time-resolved measurements yielded fluorescence lifetimes of 22–29 μs for single rovibronic levels of HNO.     

Acoustic multibubble cavitation in water: A new aspect of the effect of a rare gas atmosphere on bubble temperature and its relevance to sonochemistry

Acoustic cavitation generates transient microbubbles with extremely high temperatures and high pressures, which can provide unique reaction routes. The maximum bubble temperature attained is widely known to be dependent on the polytropic index and thermal conductivity of the dissolved gas. Here, we show for the first time experimental evidence that the bubble temperature induced by a high frequency ultrasound is almost the same among different rare gases and the chemical efficiency is in proportion to the gas solubility of rare gases, which would be closely related to the number of active bubbles.     

Explicit representations of the integral containing the error term in the divisor problem

We shall investigate several properties of the integral $$ \int_1^\infty {t^{ - \theta } \Delta _k \left( t \right) log^j t dt} $$ with a natural number k, a non-negative integer j and a complex variable θ, where Δ _k (x) is the error term in the divisor problem of Dirichlet and Piltz. The main purpose of this paper is to apply the “elementary methods” and the “elementary formulas” to derive convergence properties and explicit representations of this integral with respect to θ for k = 2.     

Magnetic neutron scattering magnetic behaviour of a low-carrier density Kondo-lattice system ceas

Abstract

We have determined the magnetic structure of a low-carrier Kondo-lattice system CeAs, and have observed a softening of the crystalline electric field excitations. Despite the prediction of a recent magnetic polaron model in which CeAs and CeP are expected to show a stacking order of T₇ and T₈ layers, CeAs does not show such a stacking structure under pressure. The ordering in the intermediate phase is a regular ferromagnetic order and that of the low-temperature phase is a canted type-I AF.     

Upper Bound on the Diameter of a Domination Dot-Critical Graph

A vertex of a graph is called critical if its deletion decreases the domination number, and an edge is called dot-critical if its contraction decreases the domination number. A graph is said to be dot-critical if all of its edges are dot-critical. In this paper, we show that if G is a connected dot-critical graph with domination number k??? 3 and diameter d and if G has no critical vertices, then d??? 2k?3.