Effect of atomic hydrogen in highly lattice-mismatched molecular beam epitaxy

Effects of atomic hydrogen on the growth of lattice-mismatched InAs/GaAs and GaAs/InP systems have been investigated. The irradiation of atomic H has resulted in a delay of the onset of formation of three-dimensional islands maintaining flat surface morphology and increase of the critical layer thickness (CLT) from 4 to 10 å in the case of the InAs/GaAs system. The effect of atomic H was shown to be dependent on the growth conditions such as the growth temperature and V/III flux ratio. The increase of CLT with atomic H irradiation may be explained by the uniform distribution of the total misfit stress in the plane of the surface as a result of enhanced two-dimensional growth by atomic H acting as a surfactant.     

Second-order necessary conditions for domain optimization problems in elastic structures,part 1: Surface traction given as a field

In this paper, domain optimization problems for both linear and nonlinear elastic structures are studied. The first variation and the second variation of the objective function are calculated in terms of the solution, of the first variation of the solution for the primal elastic system, and of the adjoint variables introduced. The adjoint variables obey a (fictitious) linear elastic system in contrast with the nonlinear adjoint systems introduced by Dems and Mróz, and by Dems and Haftka. From these results, the first-order and the second-order necessary conditions that an optimal domain should satisfy are immediately derived.Portions of this paper were presented at the 5th IFAC Symposium on Control of Distributed Parameter Systems, Perpignan, France, 1989. The authors would like to express their sincere thanks to the referees for their critical readings.     

Vanadium-doped MgAl2O4 crystals as white light source

Spinel MgAl₂O₄ crystals doped with transition metals show charge-transfer transitions for Ti:MgAl₂O₄ on one hand and multiplet transitions of (3d)-electrons for Mn:, Fe:, and Co:MgAl₂O₄ on the other hand. We will show that optical responses of V:MgAl₂O₄ are closer to those of Ti:MgAl₂O₄ and also that white emission spectrum is observed. The microscopic process of the white emission is also proposed.     

A possible vanishing of the direct diquark contributions to deep inelastic structure functions in neutrino reactions

It is shown that the direct diquark contributions to ν-induced nucleon structure functions vanish in contrast with the case of γ-induced ones if isospin and spin states of diquarks are taken into account seriously. This suggests that higher twist effects of QCD are negligible for ν-induced nucleon structure functions.     

Total synthesis of stevioside

Steviol 2 was transformed into stevioside 1 by applying the stereoselective methods of glycosidation.     

Observations of cyclotron radiations from turbulently heated plasmas (the mach II)

Cyclotron radiations at an electron cyclotron and its second harmonics frequencies were observed from a turbulently heated plasma in a strong magnetic field. The cyclotron radiations were emitted when the plasma became resistive and the electron temperature was increased. An appreciable effect of an enhanced collision of electrons in the turbulent plasma was observed on the line width.     

Electric-field-induced polar biaxial order in a nontilted smectic phase of an asymmetric bent-core liquid crystal

A polarization reorientation process has been studied by means of optical second-harmonic generation in an optically uniaxial smectic phase of an asymmetric bent-core liquid crystal. A nontilted polar smectic order with a biaxial order is induced by applying an electric field to the uniaxial nonpolar smectic phase. This phenomenon was well simulated by the two-dimensional Langevin process, i.e., electric-field-induced continuous molecular reorientation against thermal agitation. The simulation suggests that about 200s of molecules form a polar domain and cooperatively respond to the applied field. The existence of the polar domains and their reorientation are consistent to the dielectric measurement; a high dielectric constant of about 60 at the kHz range is markedly suppressed by applying a bias field.     

Quantum Reality and Measurement: A?Quantum?Logical Approach

The recently established universal uncertainty principle revealed that two nowhere commuting observables can be measured simultaneously in some state, whereas they have no joint probability distribution in any state. Thus, one measuring apparatus can simultaneously measure two observables that have no simultaneous reality. In order to reconcile this discrepancy, an approach based on quantum logic is proposed to establish the relation between quantum reality and measurement. We provide a language speaking of values of observables independent of measurement based on quantum logic and we construct in this language the state-dependent notions of joint determinateness, value identity, and simultaneous measurability. This naturally provides a contextual interpretation, in which we can safely claim such a statement that one measuring apparatus measures one observable in one context and simultaneously it measures another nowhere commuting observable in another incompatible context.