On-axis diffuse screen based on a reference-free volume hologram

A new type of hologram that elaborates upon the simplest (Gabor) on-axis hologram is suggested. The new approach makes it possible to eliminate the projected image distortions typical of the Gabor hologram. Specifically, based on a reference-free thick hologram, an on-axis holographic screen that does not transmit the zeroth order is prepared. In addition, this screen does not produce a halo and the conjugate image. It allows for recording in one spectral range and reconstruction in another, thereby greatly simplifying the choice of a light-sensitive record medium. With this screen, a color image can be projected.     

Nonlinear electronic transport in TTF-TCNQ observed by microwave harmonic mixing

The field dependent electronic conductivity of single crystals of TTF-TCNQ has been studied in both the metallic and the semiconducting range by means of microwave harmonic mixing, a method which excludes a contribution to the non-linearity by lattice heating. Because of the small strength of the applied field, the deviations from Ohm's law are also small such that they are proportional to the square of the field strength. The results in the semiconducting range are explained by the assumption of pinned charge density waves which are depinned by means of the microwave electric field.     

Synthesis and Absolute Configuration of Naturally Occurring Dactyloxene-B and -C

Natural (+)-dactyloxene-B (12) and -C (13) have been synthesized starting from (+)-trans-2, 5, 6-trimethyl-l-cyclohexene-l-carbaldehyde (1) which is shown to have the (5S, 6R)-configuration by chemical correlation with (+)-(2R, 3S, 6S)-2, 3, 6-trimethylcyclohexanone. The absolute configurations are therefore (2R, 5R, 9S, 10R) for (+)-dactyloxene-B and (2R, 5S, 9S, 10R) for (+)-dactyloxene-C.     

Large minimal realizers of a partial order II

The rank (resp. dimension) of a poset P is the cardinality of a largest (resp. smallest) set of linear orders such that its intersection is P and no proper subset has intersection P. Dimension has been studied extensively. Rank was introduced recently by Maurer and Rabinovitch in [4], where the rank of antichains was determined. In this paper we develop a general theory of rank. The main result, loosely stated, is that to each poset P there corresponds a class of graphs with easily described properties, and that the rank of P is the maximum number of edges in a graph in this class.     

Extensive air showers and Feynman scaling above 1000 GeV

We describe a method for using extensive air shower data to determine whether a Feynman scaling limit exists in the central region for inclusive cross sections. Preliminary analysis suggests that the shower muon to electron ratio is more consistent with a power law increase of pion multiplicity with energy than with the logarithmic multiplicity increase characteristic of a scaling limit, but an analysis of the intra-nuclear cascade is required to reach a firm conclusion.     

Optical pulse broadening in long fibre waveguides

As a result of research, the propagation characteristics of optical waveguides are becoming well enough understood for system evaluation. In this paper material and structural properties of the waveguide are related to measurements made on present experimental waveguides. Among the conclusions drawn from this work are that intermodal dispersion provides the dominant pulse broadening contribution but that this has been reduced to the nanosecond region by radial index gradient control. For present source spectral bandwidths, material dispersion is not a major contribution to pulse broadening. Waveguides up to 3 km long can be made with negligible intrinsic mode coupling. This gives rise to the possibility of either internal or external control to increase the information carrying capacity of the waveguide. External control has already been demonstrated. However, additional work is required to make this practical.     

Study of the reaction ¯pd→p s π+2π−π0 at 5.5 GeV/c incident momentum

A study of a 150000-picture exposure of ¯pd at 5.5 GeV/c yielded 152 events satisfying the hypothesis ¯pd→p _s π⁺2π^?π⁰. For the events with proton spectator in the momentum range 100–280 MeV/c we obtained the cross section of 0.11±0.02 mb. Assuming the validity of the impulse approximation we estimate a cross section of 0.43±0.06 mb for the reaction ¯pn→ π⁺2π^?π⁰. The rate for single ? meson production and an upper limit for double ? production are given. A modified multiperipheral Regge model was used in order to describe the general features of the data.     

Differential stability in infinite-dimensional nonlinear programming

In this paper stability properties of the extremal value function are studied for infinite-dimensional nonlinear optimization problems with differentiable perturbations in the objective function and in the constraints. In particular, upper and lower bounds for the directional derivative of the extremal value function as well as necessary and sufficient conditions for the existence of the directional derivative are given.