Diffractive production of ρ-mesons and of ρπ-systems by neutrinos and antineutrinos on protons

Evidence is presented for diffractive production of -mesons and of -systems invp and chargedcurrent interactions. In the (anti-)neutrino energy range 10 GeVE _v <60 gev=" the=" cross=" sections=" for=" diffractive="> and diffractive production are found to be (0.64±0.14 (stat.)±0.08 (syst.))% and (0.28±0.08 (stat.)±0.04 (syst.))% of the charged-current cross section. The diffractive signal is consistent with being entirely due to diffractivea ₁ production. However, the data cannot distinguish between diffractivea ₁ and diffractive nonresonant production. The experimental distributions ofW, Q ²,x _Bj andy _Bj for diffractive and events are consistent with model predictions.     

Transition metal catalyzed borylation of functional π-systems

Borylated functional π-systems are useful building blocks to enable efficient synthesis of novel molecular architectures with beautiful structures, intriguing properties and unique functions. Introduction of boronic ester substituents to a variety of extended π-systems can be achieved through either iridium-catalyzed direct C–H borylation or the two-step procedure via electrophilic halogenation followed by palladium-catalyzed borylation. This review article focuses on our recent progress on borylation of large π-conjugated systems such as porphyrins, perylene bisimides, hexabenzocoronenes and dipyrrins.     

Solid thin films of extended π -systems: Deposition,characterisation and application

This review covers the deposition, characterisation and utilisation of thin films of highly conjugated organic polymers and macrocyclic ligands. The coverage is deliberately general rather than specialised, and key references are used instead of citing an exhaustive bibliography. The literature coverage is mainly confined to 1982–1985.     

Implementation of all-optical Toffoli gate in Λ-systems

An optical Toffoli gate is the essential logical element, which permits the implementation of a reversible optical processor. We propose a simple realization of such a gate in films of crystals doped with rare-earth ions. The proposed scheme is based on adiabatic population transfer in a ??-system by means of counterintuitive and intuitive sequences of short laser pulses. We also discuss possibilities for experimental realization of the proposed gate.     

Morphology and deformation behavior of “row-nucleated” polyoxymethylene film

Crystallization from a stressed polymer melt produces not the familiar randomly nucleated spherulitic structures, but instead a highly oriented “row-nucleated” morphology. We have crystallized films of polyoxymethylene from stressed melts; just as polyethylene, the surfaces are covered with protruding lamellar edges highly oriented in the extrusion direction. There is no evidence for the more familiar spherulitic morphology. Electron microscopy directly revealed for the first time that the row nuclei are fibers, only about 200 to 300 A in diameter, extending for distances up to 10 mU. Although comprising a negligibly small amount of total sample volume, they are of prime importance in influencing how the sample will crystallize. Their presence determines, more than any other single factor, whether the sample will crystallize spherulitically or into a row-nucleated morphology. When deformed in the extrusion direction, the twisted lamellar bundles open up to form a fishnetlike structure. Simultaneously, slip between lamellae also occurs by a mechanism similar to shearing a deck of cards; for elongations up to 50%, there is little evidence of lamellar destruction. In the transverse direction, the film is brittle and fails before 1% elongation. Voids are formed at the largest lamellar “twist points” where two or more bundles are twisted together.     

On an isomonodromy deformation equation without the Painlevé property

We show that the fourth-order nonlinear ODE which controls the pole dynamics in the general solution of equation P _I ² compatible with the KdV equation exhibits two remarkable properties: (1) it governs the isomonodromy deformations of a 2 × 2 matrix linear ODE with polynomial coefficients, and (2) it does not possess the Painlevé property. We also study the properties of the Riemann-Hilbert problem associated to this ODE and find its large-t asymptotic solution for physically interesting initial data.     

SU(3) classification of p-wave ηπ and π systems

An exotic meson, the π₁(1400) with J ^PC = 1^{- +}, has been seen to decay into a p-wave ηπ system. If this decay conserves flavor SU(3), then it can be shown that this exotic meson must be a four-quark state ( qˉq + qˉq) belonging to a flavor ˉ10 representation of SU(3). In contrast, the π₁(1600) with a substantial decay mode into π is likely to be a member of a flavor octet. Received: 27 March 2002 / Accepted: 8 August 2002 / Published online: 10 December 2002 RID="b" ID="b"e-mail: klempt@iskp.uni-bonn.de Communicated by V. Vento     

The deformation texture ofβ-Sn III. Derivation of texture from elements of plastic deformation

The theoretical derivation of compression and rolling textures in -tin has been carried out for a different part in the deformation by slip and twinning for two different sets of slip systems given in the literature. The textures derived theoretically were compared with the compression and rolling textures measured in -tin in [6] and [7]. The dependence of the texture produced on the temperature of deformation is explained.     

Lüders deformation and superplastic flow of metals extruded by KOBO method

The work brings the results of the study on mechanical properties of some metallic materials subjected to very large plastic deformation by KOBO extrusion. The unexpected features of the KOBO products like Lüders deformation in pure metals and superplastic flow in coarse grain materials are discussed in terms of micro- and nano-scale elements of their structure. The choice to the experiment materials having different crystallographic and phase structure (commercial purity aluminium, multiphase aluminium 7075 alloy, pure zinc and multiphase magnesium AZ91 alloy) and different history (extrusion, casting) allowed to identify the common nano-size elements of the structure generated during the KOBO deformation which seems to be responsible for the mechanical behaviour of these materials. In particular, clusters of point defects (self-interstitials) formed under the KOBO extrusion conditions (cyclic change in the deformation path, high hydrostatic pressure) were found in these materials regardless of grain size and material early history. They correlate with appearance of unstable Lüders-like or even Portevin–LeChatelier deformation at ambient and superplastic flow at elevated temperatures.     

Cyclic deformation and fatigue cracking behaviors of Cu–28wt%Ag binary alloy

The cyclic deformation and fatigue cracking behaviors of coarse-grained Cu–28wt%Ag binary alloy were investigated under axial plastic strain amplitudes ranging from 10^?4 to 7.5 × 10^?4. It was found that the cyclic stress of the Cu–Ag alloy increased rapidly in the initial tens of cycles and became saturation with further cyclic deformation. The cyclic saturation stress increased with increasing the plastic strain amplitude. The interfaces are classified into two categories based on the orientations of the eutectic and the dendrites, i.e. type I and type II interfaces. The surface damage morphologies show that fatigue cracks normally nucleated either along the type I interfaces or along the slip bands (SBs), while no cracking occurred along the type II interface. Fatigue striations with different spacings appeared on the fracture surface, and secondary cracks along the striations were also observed. Based on the experimental results, the cyclic deformation and fatigue cracking behavior of the Cu–Ag binary alloy were discussed in detail.     

Nonrelativistic mean-field description of the deformation of Λ hypernuclei

The deformations of light Λ hypernuclei are studied in an extended nonrelativistic deformed Skyrme-Hartree-Fock approach with realistic modern nucleonic Skyrme forces,pairing correlations,and a microscopical lambda-nucleon interaction derived from Brueckner-Hartree-Fock calculations.Compared to the large effect of an additional Λ particle on nuclear deformation in the light soft nuclei within relativistic mean field method,this effect is much smaller in the nonrelativistic mean-field approximation.     

Simultaneous quantitative evaluation of in-plane and out-of-plane deformation by use of a carrier method of large image-shearing shearography

A carrier method for separating out-of-plane displacement from in-plane components based on large image-shearing shearography is presented. A reference surface is fixed on the side of a test object. They are illuminated by two expanded symmetric illuminations respectively. The carrier is introduced by rotating the reference surface to modulate the displacement of an object. By using Fourier transform to demodulate the modulated fringe pattern, two phase maps, which include out-of-plane and in-plane displacements, can be obtained. Then the out-of-plane displacement can be easily separated from in-plane displacement by subtraction and addition of the two unwrapped phase distributions. The principle of the method is presented and proved by a typical three-point-bending experiment. Experimental results show that the method enjoys high visibility of carrier fringes. The system does not need a special beam as a reference light and has simple optical setup.     

Point classification of second order ODEs and its application to Painlevé equations

The first part of this work is a review of the point classification of second order ODEs done by Ruslan Sharipov. His works were published in 1997-1998 in the Electronic Archive at LANL. The second part is an application of this classification to Painlevé equations. In particular, it allows us to solve the equivalence problem for Painlevé equations in an algorithmic form.