Magnetization Losses in Multifilament Coated Superconductors

We report the results of a study of the magnetization losses in experimental multifilament, as well as control (uniform), coated superconductors exposed to time-varying magnetic field of various frequencies. Both the hysteresis loss, proportional to the sweep rate of the applied magnetic field, and the coupling loss, proportional to the square of the sweep rate, have been observed. A scaling is found that allows us to quantify each of these contributions and extrapolate the results of the experiment beyond the envelope of accessible field amplitude and frequency. The combined loss in the multifilament conductor is reduced by about 90% in comparison with the uniform conductor at full field penetration at sweep rate as high as 3T/s

Perancangan Maskot “Planktoon Fingerboard” sebagai Upaya Meningkatkan Brand Loyalty

Planktoon known as Planktoon Fingerboard, is a company engaged in the field of life style product that has specifications field in fingerboard. Fingerboard is a skateboard's miniature that made in the same detail as the size of the original skateboard, but it has smaller size to make it more comfortable in play using the fingers. Planktoon founded in 2009, exactly 23 October 2009, from there began the management system created for branding fingerboard with pride. Planktoon brand name, logo and stationery set has been made yet before, but Planktoon has not had a mascot, just like brand competitors from Planktoon. Therefore in order to improve the image of Planktoon. Mascot hopefully can educate consumers and increase Planktoon's brand image. Designing qualitative method with interviews, observation, and existing studies to find a formula for the design concepts underlying the design of the mascot, the data analysis found a variety of unique and how branding brand with mascots that have not been known by the public, so consumers are not only given a new product continuously without any explanation interesting, with mascot be easier for consumers to understand about Planktoon. After analyzing the concepts found and a name for the mascot design Planktoon the "Smile", which means a character who has a cheerful soul, friendly, and the helper soul. The name of Planktoon's mascot is "Mr. Toon". The word is derived from the word Mr. and Toon word derived from Plank-toon to represent brand Planktoon

Secondary-Structure Design of Proteins by a Backbone Torsion Energy

We propose a new backbone-torsion-energy term in the force field for protein systems. This torsion-energy term is represented by a double Fourier series in two variables, the backbone dihedral angles phi and psi. It gives a natural representation of the torsion energy in the Ramachandran space in the sense that any two-dimensional energy surface periodic in both phi and psi can be expanded by the double Fourier series. We can then easily control secondary-structure-forming tendencies by modifying the torsion-energy surface. For instance, we can increase/decrease the alpha-helix-forming-tendencies by lowering/raising the torsion-energy surface in the alpha-helix region and likewise increase/decrease the beta-sheet-forming tendencies by lowering/raising the surface in the beta-sheet region in the Ramachandran space. We applied our approach to AMBER parm94 and AMBER parm96 force fields and demonstrated that our modifications of the torsion-energy terms resulted in the expected changes of secondary-structure-forming-tendencies by performing folding simulations of alpha-helical and beta-hairpin peptides.Comment: 13 pages, (Revtex4), 5 figure

Electronic and Magnetic Phase Diagram of a Superconductor, SmFeAsO1-xFx

A crystallographic and magnetic phase diagram of SmFeAsO1-xFx is determined as a function of x in terms of temperature based on electrical transport and magnetization, synchrotron powder x-ray diffraction, 57Fe Mossbauer spectra (MS), and 149Sm nuclear resonant forward scattering (NRFS) measurements. MS revealed that the magnetic moments of Fe were aligned antiferromagnetically at ~144 K (TN(Fe)). The magnetic moment of Fe (MFe) is estimated to be 0.34 myuB/Fe at 4.2 K for undoped SmFeAsO; MFe is quenched in superconducting F-doped SmFeAsO. 149Sm NRFS spectra revealed that the magnetic moments of Sm start to order antiferromagnetically at 5.6 K (undoped) and 4.4 K (TN(Sm)) (x = 0.069). Results clearly indicate that the antiferromagnetic Sm sublattice coexists with the superconducting phase in SmFeAsO1-xFx below TN(Sm), while antiferromagnetic Fe sublattice does not coexist with the superconducting phase.Comment: Accepted in New Journal of Physic

Self-Consistent Second Order Perturbation Theory for the Hubbard Model in Two Dimensions

We apply self-consistent second order perturbation theory (SCSOPT) with respect to the on-site repulsive interaction U to study the Hubbard model in two dimensions. We investigate single particle properties of the model over the entire doping range at zero temperature. It is shown that as doping decreases toward half-filling $\omega$-mass enhancement factor increases, while k-mass enhancement factor decreases. The increase in $\omega$-mass enhancement factor is larger than the decrease in k-mass enhancement factor, so that total-mass is larger than that in the non-interacting case. When particle number density per unit cell n is given by 0.64<n<1.0 interaction enhances anisotropy of the Fermi surface, whereas at lower densities n<0.64 interaction suppresses anisotropy of it. Due to the decrease in k-mass enhancement factor the density of states (DOS) at the Fermi level is suppressed. It is possible to understand the results within the framework of the weak coupling Fermi liquid theory.Comment: 8 pages, 12 embedded EPS figures, to appear in J. Phys. Soc. Jpn. Vol. 68-3 (1999

AN EXPERIMENTAL AND MODELING STUDY OF ELECTROOSMOTIC BULK AND NEAR-WALL FLOWS IN TWO-DIMENSIONAL MICRO-AND NANOCHANNELS

ABSTRACT Electrokinetically driven flow of electrolyte solutions through micro-and nanochannels is of interest in microelectromechanical systems (MEMS) and nanotechnology applications. In this work, fully developed and steady electroosmotic flow (EOF) of dilute sodium tetraborate and sodium chloride aqueous solutions in a rectangular channel where the channel height h is comparable to its width W is examined. EOF is also studied under conditions of electric double layer (EDL) overlap, or λ/h ~ O(1), where λ is the Debye thickness, for very dilute solutions. The initial experimental data and model results are in very good agreement for dilute sodium tetraborate solutions. The experimental work uses the new nano-particle image velocimetry (nPIV) technique. Evanescent waves from the total internal reflection of light with a wavelength of 488 nm at a refractive index interface is used to illuminate 100 nm neutrally buoyant fluorescent particles in the near-wall region of the flow. The images of these tracer particles over time are processed to obtain the two components of the velocity field parallel to the wall in fully developed EOF of sodium tetraborate at concentrations up to 2 mM in fused quartz rectangular channels with height h up to 10 microns. The spatial resolution of these velocity field data along the dimension normal to the wall is about 100 nm, and the data are obtained within a distance of approximately 100 nm of the wall based upon the 1/e intensity point, or penetration depth. A set of equations modeling EOF in a long channel are solved where h/L &lt;&lt; 1, and L is the lengthscale along the flow direction. Unlike most previous models, this work does not use the Debye-Huckel approximation, nor does it assume symmetric boundary conditions. For the case where λ/h &lt;&lt; 1, analytical solutions for the velocity, potential and mole fractions are obtained using an asymptotic perturbation approach

Magnetization Losses in Multiply Connected YBa2Cu3O6+x Coated Conductors

We report the results of a magnetization losses study in experimental multifilament, multiply connected coated superconductors exposed to time-varying magnetic field. In these samples, the superconducting layer is divided into parallel stripes segregated by non-superconducting grooves. In order to facilitate the current sharing between the stripes and thus increase the reliability of the striated conductors, a sparse network of superconducting bridges is superimposed on the striated film. We find that the presence of the bridges does not substantially increase the magnetization losses, both hysteresis and coupling, as long as the number of bridges per length of the sample is not large. These results indicate that it is possible to find a reasonable compromise between the competing requirements of connectivity and loss reduction in an ac-tolerant version of the high temperature coated conductors specifically designed for ac power applications.Comment: 19 pages, 12 figures to be published in J. Appl. Phy

Interaction induced collapse of a section of the Fermi sea in in the zig-zag Hubbard ladder

Using the next-nearest neighbor (zig-zag) Hubbard chain as an one dimemensional model, we investigate the influence of interactions on the position of the Fermi wavevectors with the density-matrix renormalization-group technique (DMRG). For suitable choices of the hopping parameters we observe that electron-electron correlations induce very different renormalizations for the two different Fermi wavevectors, which ultimately lead to a complete destruction of one section of the Fermi sea in a quantum critical point