Modification of Mössbauer reflection spectra of group AIIBVI single crystals with Fe<Superscript>57</Superscript> nuclei under influence of infrared radiation

Interaction of Mössbauer gamma radiation with ultrasound vibrations in group AIIBVI single crystals of CdS and CdSe with Fe⁵⁷ impurity nuclei under action of infrared radiation is investigated. It is shown that the infrared irradiation excites a phonon field in single crystals. Similar to the case of optical irradiation of single crystals the shape of their Mössbauer spectrum is modified. The effect of double modulation of resonant gamma radiation by infrared radiation has been observed.     

Transitions Between Quantized Standing Waves at Interactions with an Atom in the Raman–Nath Regime

The interaction of an atom with an electromagnetic field induces transitions between its quantized modes, in which cos- and sin-standing waves are chosen as the basis for quantization. The number of photons in the modes were calculated in the Raman–Nath regime in the approximation of adiabatic following. It is shown that in the course of transitions an initially populated mode is generally not completely emptied, and the oscillating part of photons increases with the total number in the system.     

Finite Element Analysis Of Thermal Characteristics in Continuous Wave Long Wavelength Surface Emitting Lasers (I): Dielectric Cavity Structures

We numerically analyzed the thermal characteristic in continuous wave (cw) GalnAsP/InP surface emitting lasers with dielectric multilayer mirrors by using finite element method. From the simulation of temperature distribution in cw devices, we found that MgO/Si multilayer mirror which has a high thermal conductivity is effective for heat sinking; the thermal resistance of device using MgO/Si mirror is nearly half of that using SiO₂/Si one, almost independently of their thicknesses. It was also indicated that the optimum design for other structural parameters, especially the thickness of active region, is important to effectively suppress the temperature increase. The minimum threshold current was estimated to be 3 mA under cw condition for the active region diameter of 4 μm and thickness of 0.5 μm.     

A Microoptic Network Unit Using Planar Microlens Array

We propose a new concept for an optical network unit using planar microlens array for fiber to the home networks. It is expected from this modeling that an optical coupling loss of 2.5 dB, a polarization dependent loss of 0.5 dB and an extinction ratio larger than 50 dB can be achieved. The structure design and its fabrication method are discussed.     

Neutral strange particle correlations in 360 GeV/cpp interactions

Production properties and correlations forK _s ⁰ K _s ⁰ ,K _s ⁰ Λ,K _s ⁰ ¯Λ and Λ¯Λ systems in 360 GeV/cpp interactions are presented. All rapidity gap distributions are observed to peak at Δy=0 and the azimuthal angular distributions between the two particles are consistent with being flat. Experimental results are compared with the quark fusion and Lund models of particle production.     

A pinhole-plate ultrasonic atomizer

A new pinhole-plate ultrasonic atomizer has been proposed and developed. A pinhole-plate having one or more pinholes is joined to a cavity filled with liquid and is vibrated by a circular ring piezoelectric element bonded onto it. The vibrating plate generates ultrasonic waves only in the vicinity of the pinholes to jet and atomize the liquid from them. The atomizer is very simple and compact, and extremely low in power consumption.     

Formation of negative ions by electron impact on SiF4 and CF4

First measurements of cross sections for the formation of negative ions by electron attachment to SiF₄ and CF₄ are reported for an electron impact energy range of 0 to 50 eV. The energies at which the various ions appear and the positions at which the ionization efficiency curves peak have been obtained and compared with previous measurements. Thermochemical data have been used to predict and identify the various channels of dissociation. Cross sections for the production of ion pairs through the process of polar dissociation have also been measured.Visiting fellow, on leave of absence from Universidade Federal de Sao Carlos, Departamento de Quimica, 13560, Sao Carlos, SP, Brazil     

Effect of fullerenes and gamma-irradiation on the adhesive strength of model adhesive joints

The dependence of the adhesive strength of model glass/binder/glass adhesive compositions cured with aliphatic and aromatic hardeners on the γ-radiation dose was studied. It was shown that the strength of the fullerene-modified binder decreases at low absorbed doses (to 20 kGy), whereas the strength of the composition with the aliphatic binder increases again with an increase in the dose in the range 140–240 kGy, although its does not reach that of the unirradiated composite.     

Spatial modulation of X-rays in the presence of external acoustic field

The two-crystal X-ray diffraction from (111?1) reflecting atomic planes of quartz single crystal with AT-cut was experimentally considered in the Laue geometry, when both the crystals are simultaneously in the field of bulk acoustic waves. It is shown that as a result of spatial modulation of reflected beam an odd number of parallel X-ray beams is obtained.