Parity violation in SLAC experiment and left-right symmetric gauge models

It is shown that the left-right symmetric gauge models based on the group $\text{G}$ = SU(2)_L × SU(2)_R × U(1)_L × U(1)_R can accommodate quite naturally the results of the recent SLAC experiment concerning parity violation in neutral currents. The possibility of finding a light neutral gauge boson in the PETRA-PEP energy range remains particularly interesting.     

EVIDENCE FOR HIGH ENERGY STORAGE INTERMEDIATES IN BIOLUMINESCENCE

Abstract— The bioluminescent enzyme from Photobacterium fischeri is normally activated in vifro by reaction with FMNH₂ and O₂. in the presence of a long-chain aldehyde. Emission from enzyme intermediates in this reaction continues for several seconds, and if the mixture is frozen just after initiation of the reaction, this presumptive emission may be delayed until the system is warmed again. Light is then emitted in a fashion analogous to thermo-luminescent emission, with a maximum intensity at — 10°C. The experiments described here show that the total amount of light which is emitted under these conditions no longer depends so much upon aldehyde, a relatively high quantum yield being obtained both with and without aldehyde.
It is further shown that bioluminescence may be activated by light, populating it is believed, the same state which is responsible for the emission in the case of the FMNH₂-induced emission. The light-induced reaction does not depend on flavin in the enzyme preparations, nor does the activation spectrum resemble that of a flavoprotein. Activation may be carried out in the solid state at temperatures down to at least — 100°C, and so does not involve the diffusion of large molecules. It is proposed that energy storage takes place by charge separation, and that the excited state from which emission takes place is associated with charge recombination.     

Tetramethylcyclobutadiene radical cation

The tetramethylcyclobutadiene radical cation has been generated photochemically in solutions of aluminum halide σ complexes of tetramethylcyclobutadiene. It decays thermally to a “dimeric” radical cation.     

Superconductivity of Nb/Cu superlattices

The superconducting transition temperature T_c of Nb/Cu superlattices has been investigated as a function of layer thickness. The dependence of T_c above 300 Å layer thickness agrees well with proximity effect theory with no adjustable parameters. Below 300 Å, the data in conjunction with current proximity theory shows that T_c of Nb decreases with layer thickness. This is interpreted as changes in the electronic density of states due to a decrease in the mean-free path.     

Alcaloïdes stëroïdiques—cxi Influence D'un Groupement Hydroxyle sur la Fragmentation D'amines,Amides et Imines Stéroïdiques en Spectrométrie de Masse

The presence of a hydroxyl group in steroidal amines, amides and imines, may profoundly influence their fragmentation in the mass spectrometer. This fragmentation is initiated by the rearrangement of the hydroxylic hydrogen on the nitrogen containing groups and products ions characteristic of the OH site in the molecule. Sometimes this may occur even when the two groups are situated at remote positions.     

Superconducting properties of V/Fe superlattices

We report measurements on the superconducting properties of V/Fe superlattices with various layer thicknesses. These samples were prepared with a novel UHV evaporator which can produce up to twenty different samples in the same run. The Fe layer, a strong pair breaker, suppresses the superconducting transition temperature in a systematic way. When the V layer thickness is on the order of the BCS coherence length and the Fe layer is only a few atomic planes thick, a 2D–3D crossover has been observed in the temperature dependence of the parallel upper critical field H_C2∥. This implies the coexistence of superconductivity and ferromagnetismm. We observe three dimensional behavior for thinner Fe layers (～1 atomic plane) and two dimensional behavior for thicker Fe layers (greater than 10 atomic planes).     

Shakedown of unidirectional composites

The shakedown problem for a composite lamina made of an elastic-plastic matrix and elastic cylindrical fibers is studied. The plastic deformation modes of the lamina are reviewed, and it is concluded that significant shakedown effects can be caused only by the I₁ = 1/2(T₁₁ + T₂₂) and I₂ = T₃₃ components of the remotely applied stress field which are symmetric about the axis x₃ of the fiber; T₁₁ and T₂₂ are the normal composite stresses in the transverse plane. It is shown that the I₁I₂ stress system is needed also to represent thermal loads caused by a uniform change of temperature in the composite.Two methods for evaluation of shakedown limits in the I₁I₂-plane are described. First, the classical approach involving the determination of parametric families of self-stress fields and the solution of mathematical programming problems is used. Results are presented for selected B-Al, Be-Al, B-Ti and B-Mg composites.In the second method, the shakedown problem is related to the recently developed kinematic hardening rules for fibrous composites. It is shown that the composite will shake down for any loading program within a prescribed domain in the I₁I₂-plane, providing that the domain can be contained within a translated initial yield surface. This approach leads to a closed-form evaluation of shakedown limits for any arbitrary combination of mechanical and thermal variable cyclic loads in fibrous composites with temperaturedependent matrix yield strengths.The relationship between shakedown and fatigue in metal matrix composites is discussed.     

Synthesis of In<Subscript>2</Subscript>O<Subscript>3</Subscript>nanoparticles by thermal decomposition of a citrate gel precursor

This paper describes the synthesis of indium oxide by a modified sol–gel method, and the study of thermal decomposition of the metal complex in air. The characterization of the intermediate as well as the final compounds was carried out by thermogravimetry, differential thermal analysis, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and small angle X-ray scattering. The results show that the indium complex decomposes to In₂O₃ with the formation of an intermediate compound. Nanoparticles of cubic In₂O₃ with crystallite sizes in the nanosize range were formed after calcination at temperatures up to 900°C. Calcined materials are characterized by a polydisperse distribution of spherical particles with sharp and smooth surfaces.This revised version was published online in August 2005 with a corrected issue number.     

Study of traffic flow at an unsignalized T-shaped intersection by cellular automata model

In this paper, the traffic flow at an unsignalized T-shaped intersection in which there are three input directions of vehicles and two right-turnings and one left-turning has been investigated by using the cellular automata traffic model. The interactions between vehicles on different lanes and effects of traffic flow states of different roads on capacity of T-shaped intersection system are analyzed. The phase transition characteristics of traffic states on different lanes are studied. The research indicates that the model can be applied to the real traffic analysis and traffic forecast.     

Aharonov-Carmi effect and energy shift of valence electrons in rotating C60 molecules

The molecular Aharonov-Carmi (A-C) effect is considered for C60 molecules. It is shown that the valence electrons in rapidly rotating C60 molecules acquire an A-C phase shift, which is proportional to the molecular angular velocity flux enclosed by the valence-electron matter wave on the C60 molecular shell. The energy shift of the valence electrons due to both the molecular rapid rotation and the molecular A-C phase shift is calculated.