Properties of lift-off structured high Tc microbridges

Microbridges and DC SQUIDs (superconducting quantum interference devices) were fabricated, using a lift-off technique, from RF sputtered YBaCuO films on MgO single-crystal substrates. Microwave measurements at 9 GHz on microbridges and the magnetic-field dependence of their critical current reveal wide bridge behaviour up to temperatures near the maximum operating temperature of the bridge. Mostly, a linear dependence of the critical current on the temperature is found, which is connected with high intrinsic 1/f noise if the bridge is constant-current-biased slightly above the critical current. In some bridges and DC SQUIDs, regimes with a temperature dependence proportional to (1-T/Tc)1.5 are found. In this case the 1/f noise level is much smaller and SQUID modulation can be followed to about 65

ARXPS-studies ofcˆ-axis textured YBa2Cu3Ox-films

YBa2Cu3Ox sputter deposited cold on MgO grows in O2 annealing epitaxially to a transparent, superconducting film with Tc 80K. The unscraped surfaces of these films are smooth showing XPS lines changing with photoelectron take-off angle. This enhanced data base allows to separate the different chemical compounds (hydroxide, peroxide, carbonate, carboxyle, cuprate, graphite ...) and to obtain their spatial distribution. This yields the compounds, their amount and distribution making up the cinder growing with O2-anneal at internal and external surfaces. The cinder stoichiometry gives insights in the chemistry going on in O2 annealing. Below the cinder the signature ofcˆ-axis oriented YBa2Cu3Ox is identified, showing that a Ba-oxide layer forms the stable surface. This coats insulating CuO2 and Y-oxide layers yielding so an intrinsic dead layer

Encoding algebraic power series

Algebraic power series are formal power series which satisfy a univariate polynomial equation over the polynomial ring in n variables. This relation determines the series only up to conjugacy. Via the Artin-Mazur theorem and the implicit function theorem it is possible to describe algebraic series completely by a vector of polynomials in n+p variables. This vector will be the code of the series. In the paper, it is then shown how to manipulate algebraic series through their code. In particular, the Weierstrass division and the Grauert-Hironaka-Galligo division will be performed on the level of codes, thus providing a finite algorithm to compute the quotients and the remainder of the division.Comment: 35 page

Stopping power of antiprotons in H, H2, and He targets

The stopping power of antiprotons in atomic and molecular hydrogen as well as helium was calculated in an impact-energy range from 1 keV to 6.4 MeV. In the case of H2 and He the targets were described with a single-active electron model centered on the target. The collision process was treated with the close-coupling formulation of the impact-parameter method. An extensive comparison of the present results with theoretical and experimental literature data was performed in order to evaluate which of the partly disagreeing theoretical and experimental data are most reliable. Furthermore, the size of the corrections to the first-order stopping number, the average energy transferred to the target electrons, and the relative importance of the excitation and the ionization process for the energy loss of the projectile was determined. Finally, the stopping power of the H, H2, and He targets were directly compared revealing specific similarities and differences of the three targets.Comment: v1: 12 pages, 8 figures, and 1 table v2: 15 pages, 9 figures, and 2 tables; extended discussion on IPM in Method; influence of double ionization on stopping power discussed in Result

Further Developments in Process Mapping and Modelling in Direct Metal Selective Laser Melting

This paper advances previous reported work on the mapping and modelling of single tracks and layers produced in powder beds of tool steel and stainless steel powders by a CO2 laser. For single tracks it reports on predicted and simulated track masses. It validates the simulations, including the use of absorption close to 1.0 when cylindrical tracks are formed. It also reports on melt pool temperature calculations and estimated melt pool dimensions which are used, in conjunction with bed physical properties, to explain why the single tracks form as either continuous with a crescent shape cross-section, continuous with an elliptical section, discontinuously irregularly broken, discontinuously balled or only partially melted as scan speeds and laser powers change. It then extends its scope, experimentally, to consider effects of scan spacing on single layer formation.Mechanical Engineerin

Parental Psychological Control and Autonomy Granting: Distinctions and Associations with Child and Family Functioning

Objective:This study utilized an observational coding scheme to identify parenting behavior reflecting psychological control and autonomy granting, and examined relations between these parenting dimensions and indices of child and family functioning. Design: A community sample of 90 preadolescents (aged 10.5 to 12 years) and both of their parents engaged in a triadic interaction that was coded for parental psychological control and autonomy granting. Participants also completed measures of child adjustment, interparental conflict, and triangulation. Results: Factor analyses indicated that a two-factor model better fit the data than a one-factor model, suggesting that psychological control and autonomy granting are best conceptualized as independent but related constructs. Parental psychological control and autonomy granting exhibited some shared and some unique correlates with indices of child and family functioning. Hierarchical regressions revealed significant interactions between these dimensions, suggesting that the strength of some associations between parents\u27 use of psychological control and youth adjustment problems depends on the level of autonomy granting exhibited by the parent. Conclusions: By examining psychological control and autonomy granting simultaneously as unique constructs, this study identifies patterns of psychological control and autonomy granting that undermine youth adjustment. Findings inform targeted intervention efforts for families of preadolescent youth