Woven codes with outer warp: variations, design, and distanceproperties

We consider convolutional and block encoding schemes which are variations of woven codes with outer warp. We propose methods to evaluate the distance characteristics of the considered codes on the basis of the active distances of the component codes. With this analytical bounding technique, we derived lower bounds on the minimum (or free) distance of woven convolutional codes, woven block codes, serially concatenated codes, and woven turbo codes. Next, we show that the lower bound on the minimum distance can be improved if we use designed interleaving with unique permutation functions in each row of the warp of the woven encoder. Finally, with the help of simulations, we get upper bounds on the minimum distance for some particular codes and then investigate their performance in the Gaussian channel. Throughout this paper, we compare all considered encoding schemes by means of examples, which illustrate their distance properties     

Influence of boron and oxygen on the microstructure and mechanical properties of high-strength Ti66Nb13Cu8Ni6.8Al6.2 alloys

The influence of boron additions and different oxygen contamination levels on the microstructure and the mechanical properties in the Ti_66?xNb₁₃Cu₈Ni_6.8Al_6.2B_x (0 ? x ? 1) system were investigated. The alloys were prepared by levitation copper mould casting as rods with a diameter of 5 mm using different grades of starting elements. The alloy without boron exhibits a maximum compressive stress of more than 2500 MPa, associated with a compressive strain of more than 30%. The ultimate tensile stress is ～1075 MPa with a maximum elongation of 1.6%. Increased oxygen content leads to a rise of yield strength due to solid solution hardening. Boron additions promote grain refinement and reinforce the interdendritic phase compound by forming needle-like TiB precipitates. This change in microstructure increases the yield stress and the Young’s modulus and lowers the plastic strain. The microstructure was analysed in terms of the boron content by means of scanning electron microscopy, Auger electron spectroscopy and transmission electron microscopy. The presented mechanical properties are compared with the compression and tensile properties of the commercially available Ti6Al4V ELI (ELI = extra low interstitial) alloy.     

Diluted and Concentrated Isoelectronic Substitutional Effects in Superconducting R x Y1−x Ni2B2C Compounds

The suppression of superconductivity of pseudo-quaternary R _xY_1–x Ni₂B₂C compounds in the dilute limit was found to be mainly caused by magnetic pair-breaking in the case of the heavy rare-earth elements (R = Tm, Er, Ho, Dy, Tb, Gd) and by lattice distortions in the case of the light rare-earth elements (R = Pr, Nd) resulting from the large difference of the ionic radii between the Y host ions and the R impurity ones     

An ECR-RFQ ion beam facility for materials research with highly charged slow ions

An ion beam facility is described which can produce intense beams of very highly charged ions with variable energy in the keV and MeV regime. This facility consists of an electron cyclotron resonance ion source (ECR) and a radiofrequency quadrupole accelerating structure (RFQ). It provides a relatively cheap and compact device for material research with highly charged ions at surfaces as well as for deep-lying solid layers.     

The High Field Project at Dresden/Rossendorf: A Pulsed 100 T/10 ms Laboratory at an Infrared Free-Electron-Laser Facility

This article describes the project to build a pulsed magnetic field user laboratory at the Forschungszentrum Rossendorf near Dresden. Using a 50 MJ/24 kV capacitor bank, pulsed fields and rise times of 100 T/10 ms, 70 T/100 ms, and 60 T/1 s should be achieved. The laboratory will be built next to a free-electron-laser-facility for the middle and far infrared (5 to 150 µm, 2 ps, cw). We describe the work which has been performed until now to start the construction of the laboratory in 2003: coil concepts and computer simulations, materials development for the high field coils, and design of the capacitor bank modules. In addition, a pilot laboratory has been set up where fields up to 62 T/15 ms have been obtained with a 1 MJ/10 kV capacitor module. It is used to gain experience in the operation of such a facility and to test various parts of it. In this test laboratory special devices have been developed for measurements of magnetization and magnetoresistance, and have been successfully used to investigate various materials including semiconductors and Heavy Fermion compounds. In particular, metamagnetic transitions in intermetallic compounds and the irreversibility field of a high-T _c superconductor have been determined. Shubnikov–de Haas oscillations have been observed in the semimetallic compound CeBiPt. Resistance relaxation has been observed to start less than 1second after the field pulse. It could be shown for the first time that nuclear magnetic resonance (NMR) is detectable in pulsed fields.     

Electronic Structure and Superconductivity of Nonmagnetic Transition Metal Borocarbides

The electronic structure of tetragonal (RC(N))_m(TB)₂, m=1–3, compounds, with R= Y,Lu,La, T=Ni,Pt is studied. Total and partial densities of states N(E) are calculated and compared with orbital resolved x-ray absorption data. Special attention is paid to the structure of N(E) near the Fermi-level and its consequences for thermodynamic properties in the superconducting and the normal states. A medium el-ph coupling constant 0.5 1.2 is found. There is no simple correlation between N(0) and T _c . The analysis of the upper critical field reveals the presence of at least two groups of electrons with quite different Fermi velocities v _F in accord with dHvA data, and with calculated distributions of v _F around the Fermi surface     

Quantum Transport and Cyclotron Resonance Study of Ge/SiGe Quantum Wells in High Magnetic Fields

Shubnikov-de Haas oscillation and cyclotron resonance were studied for high mobility p-type Ge channels in strained Ge/Si_1?x Ge _x quantum wells, using pulsed high magnetic fields up to 50 T. Fine quantum oscillations were observed in ρ _xx . Reflecting the complex Landau level structure in the nearly degenerate valence bands, the Fourier transform of the oscillatory spectra consists of several peaks. Cyclotron resonance was measured at photon energies between 10 and 17 meV. Two well-defined resonance peaks were observed in two samples with different x, resulting in different strains. A large non-parabolicity and large strain dependence of the effective masses were observed.     

Review of Counseling and psychotherapy of work dysfunctions.

Reviews the book, Counseling and psychotherapy of work dysfunctions by Rodney L. Lowman (see record 1993-98413-000). Dr. Lowman's book on work dysfunctions serves as a seminal product for further understanding a much-neglected component of the lives of the many men and women who seek psychological assistance in working through issues around their employment. The book conveys in a well-written, sometimes humorous, style that "work is a natural part of living, and the issues it raises are important parts of character." The overall impression is that of a well-thought-out and most readable book. There is no doubt in this reviewer's mind that it will become essential reading for psychologists, social workers, family therapists, and graduate students who are becoming increasingly involved in this field of study. What this reviewer found very helpful was the clarity of presentation of the assessment techniques as well as the amply illustrated intervention modules that may be utilized. To this reviewer, there is no doubt that this is one area for psychologists' contributions in the future--the work area. Lowman's book gives us basic material from which to continue to build our profession in a new and exciting direction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Anomalous Behaviour of PrNi2B2C Borocarbide

Electrical resistivity (T), specific heat C _p(T), magnetic susceptibility (T), and magnetization M(H) have been measured for polycrystalline PrNi ₂ B ₂ C. Maxima in C _p(T) and |d(T)/dT| dependencies were found at T _N 4.3 K connected with AFM ordering observed earlier by neutron diffraction. The Sommerfeld coefficient is at least 250 mJ/mol K ² . The values of T _N for PrNi ₂ B ₂ C and |dT _c /dx| for Y _1–x Pr _x Ni ₂ B ₂ C were found to be much larger than estimated by the de Gennes scaling from the Gd-based borocar-bides. These facts as well as anomalous decrease of (T) found below 20K are connected with moderate heavy fermion behaviour of antiferromagnetic PrNi ₂ B ₂ C.     

Comparison of Room Temperature and Cryo-Deformation Effects on Mechanical Properties and Microstructure of Copper

The objective of this work is to study the effect of room temperature (RT) and liquid nitrogen temperature (LNT) rolling on mechanical properties of the pure copper. For the same percentage deformation, LNT samples show a significant increase in tensile strength and hardness value compared to RT samples. Microstructural investigation shows a large misorientation change between RT and LNT samples when we use grain orientation spread (GOS) as a measure of microstructural change. The mechanical property and microstructural changes are correlated with calorimetry experiments. We also present some preliminary results from our work on wire drawing at RT and LNT.