Critical phenomena in high-energy lepton- and hadron-induced reactions

We argue that the nucleon seen in the Bjorken scaling region is a gas of quasi-free partons. As x decreases, for certain values of Q ² the partons in a nucleon coalesce to a liquid (saturation). Experimentally this phenomenon is manifested as the turn-over of the structure function derivatives. The phenomenon can be quantified in the framework of statistical models, percolation and other approaches to collective effects in the strongly interacting matter. Similarities and differences between the case of lepton-hadron, hadron-hadron and heavy-ion collisions are discussed.     

Q-switched Yb 3+ :YVO 4 laser with Raman self-conversion

We report the efficient continuous-wave (CW) and Q-switched laser operation of a diode-pumped Yb:YVO₄ laser. A CW output power of 1 W with a slope efficiency of 59% with respect to absorbed pump power was demonstrated. Passively Q-switched with a Cr⁴⁺:YAG saturable absorber, a Yb:YVO₄ laser with Raman conversion was demonstrated. Q-switched 18.7- J pulses with a pulse duration of 17 ns and a peak power up to 1 kW were obtained at 1018-nm fundamental wavelength and 3.6- J pulses with a pulse duration of 6 ns and a peak power of about 0.6 kW were obtained at 1119.5-nm first-Stokes wavelength.This revised version was published online in March 2005. In the previous version, the published online date was missing     

Yb3+-doped YVO4 crystal for efficient Kerr-lens mode locking in solid-state lasers

We report the first demonstration, to our knowledge, of soft-aperture Kerr-lens mode locking in a diode-pumped femtosecond Yb3+:YVO4 laser. Near-transform-limited pulses as short as 61 fs are generated around a center wavelength of 1050 nm with an output power of 54 mW and a pulse repetition frequency of 104.5 MHz. This is, to our knowledge, the shortest pulse generated directly from an Yb laser having a crystalline host material. The femtosecond operation has a mode-locking threshold at an absorbed pump power of 190 mW. The nonlinear refractive indexes of the Yb3+:YVO4 crystal have been measured to be 19 x 10(-16) cm2/W and 15 x 10(-16) cm2/W for the sigma and pi polarizations, respectively, at 1080 nm.     

Spectroscopy and continuous-wave diode-pumped laser action of Yb3+:YVO4

The growth, spectroscopic properties, and laser performance of Yb:YVO4 crystal with laser diode pumping are reported. A peak absorption cross section of 7.4 x 10(-20) cm2 at 985 nm, a radiative lifetime of 0.25 ms, and a stimulated-emission cross section of 1.25 x 10(-20) cm2 at 1008 nm for pi polarization were determined for the Yb3+ ions in YVO4. Continuous-wave laser action of Yb:YVO4 at 1020-1027 nm was demonstrated with an output power of 610 mW and a slope efficiency of 49%.     

Mechanism of single-spin asymmetries generation in the inclusive hadron processes

We discuss a nonperturbative mechanism for generation of the single-spin asymmetries in hadron interactions. It is based on the chiral quark model combined with unitarity and impact parameter picture and provides explanation for the experimental regularities observed under the measurements of the spin asymmetries.     

Reaction of silicon tetrafluoride with calcium hydride as a propagating wave

The synthesis of silane by reacting silicon tetrafluoride and calcium hydride is shown to proceed as a propagating wave. The main parameters of the process, namely, the propagation velocity, the reaction front temperature, and calcium conversion, are determined. The mathematical model of wave propagation for an exothermic reaction in a porous medium with purging a gaseous oxidant describes qualitatively the major laws of the process.     

Determination of hydration numbers by IR spectrometry

The use of precision IR spectrometry for determining the hydration numbers of species in organic phase was considered. The hydration numbers of HAuCl₄ (n = 3), HFeCl₄ (n = 3), HNO₃ (n = 0), HClO₄ (n = 2), and HCl (n = 1) in 0.64 M (15 vol. %) TBP in CCl₄ were determined.     

Determination of hydration numbers of acids in organic phase by IR spectrometry

By the precision infrared spectrometry the hydration numbers n were determined for a series of acids in 0.64 M tributyl phosphate (CCl₄) and acetonitrile at a concentration of free water 0.01–0.1 M. In tributyl phosphate n = 3.1±0.3 (HAuCl₄); 2.9±0.3 (HFeCl₄); 1.9±0.2 (HClO₄); 1.0±0.2 (HNO₃); 1.0±0.1 (HCl). In acetonitrile n = 3.1±0.7 (HAuCl₄); 1.1±0.4 (HFeCl₄); 2.1±0.2 (HClO₄), 0±0.05 (HNO₃); 0.1±0.15 (HCl).