24,971 research outputs found
Relationship science and interventions: Where we are and where we are going
Relationship distress and divorce often have profound effects on couples and their children. Relationship science has long sought to prevent and alleviate relationship distress; this chapter is a summary of many important recent developments in the field. Ongoing challenges in studying and assisting intimate relationships are also discussed
Dependence of the superconducting critical temperature on the number of layers in homologous series of high-Tc cuprates
We study a model of -layer high-temperature cuprates of homologous series
like HgBa_2Ca_(n-1)Cu_nO_(2+2n+\delta) to explain the dependence of the
critical temperature Tc(n) on the number of Cu-O planes in the elementary
cell. Focusing on the description of the high-temperature superconducting
system in terms of the collective phase variables, we have considered a
semi-microscopic anisotropic three-dimensional vector XY model of stacked
copper-oxide layers with adjustable parameters representing microscopic
in-plane and out-of-plane phase stiffnesses. The model captures the layered
composition along c-axis of homologous series and goes beyond the
phenomenological Lawrence-Doniach model for layered superconductors.
Implementing the spherical closure relation for vector variables we have solved
the phase XY model exactly with the help of transfer matrix method and
calculated Tc(n) for arbitrary block size , elucidating the role of the
c-axis anisotropy and its influence on the critical temperature. Furthermore,
we accommodate inhomogeneous charge distribution among planes characterized by
the charge imbalance coefficient being the function of number of layers
. By making a physically justified assumption regarding the doping
dependence of the microscopic phase stiffnesses, we have calculated the values
of parameter as a function of block size in good agreement with the
nuclear magnetic resonance data of carrier distribution in multilayered high-Tc
cuprates.Comment: 15 pages, 10 figures. Submitted to Physical Review
Physical aggression, compromised social support, and 10-year marital outcomes: Testing a relational spillover model
The purpose of the present study was to test a relational spillover model of physical aggression whereby physical aggression affects marital outcomes due to its effects on how spouses ask for and provide support to one another. Newlywed couples (n = 172) reported levels of physical aggression over the past year and engaged in interactions designed to elicit social support; marital adjustment, and stability were assessed periodically over the first 10 years of marriage. Multilevel modeling revealed that negative support behavior mediated the relationship between physical aggression and 10-year marital adjustment levels whereas positive support behavior mediated the relationship between physical aggression and divorce status. These findings emphasize the need to look beyond conflict when explaining how aggression affects relationships and when working with couples with a history of physical aggression who are seeking to improve their relationships
Tapered, tubular polyester fabric
A tapered tubular polyester sleeve is described to serve as the flexible foundation for a spacesuit limb covering. The tube has a large end and a small end with a length to be determined. The ratio of taper is also determined by scale factors. All the warp yarns extend to the large end. A requisite number of warp yarns extend the full length of the sleeve. Other warp yarns extend from the large end but are terminated along the length of the sleeve. It is then woven with a filling yarn which extends in a full circle along the full length of the sleeve to thereby define the tapered sleeve. The sleeve after fabrication is then placed on a mandrel, heated in an oven, and then attached to the arm or other limb of the spacesuit
Nonequilibrium steady states of driven magnetic flux lines in disordered type-II superconductors
We investigate driven magnetic flux lines in layered type-II superconductors
subject to various configurations of strong point or columnar pinning centers
by means of a three-dimensional elastic line model and Metropolis Monte Carlo
simulations. We characterize the resulting nonequilibrium steady states by
means of the force-velocity / current-voltage curve, static structure factor,
mean vortex radius of gyration, number of double-kink and half-loop
excitations, and velocity / voltage noise spectrum. We compare the results for
the above observables for randomly distributed point and columnar defects, and
demonstrate that the three-dimensional flux line structures and their
fluctuations lead to a remarkable variety of complex phenomena in the
steady-state transport properties of bulk superconductors.Comment: 23 pages, IOP style, 18 figures include
Boundary Conditions for the Einstein Evolution System
New boundary conditions are constructed and tested numerically for a general
first-order form of the Einstein evolution system. These conditions prevent
constraint violations from entering the computational domain through timelike
boundaries, allow the simulation of isolated systems by preventing physical
gravitational waves from entering the computational domain, and are designed to
be compatible with the fixed-gauge evolutions used here. These new boundary
conditions are shown to be effective in limiting the growth of constraints in
3D non-linear numerical evolutions of dynamical black-hole spacetimes.Comment: 21 pages, 12 figures, submitted to PR
Low speed and angle of attack effects on sonic and near-sonic inlets
Tests of the Quiet, Clean Short-Haul Experimental Engine (QCSEE) were conducted to determine the effects of forward velocity and angle of attack on sonic and near-sonic inlet aerodynamic performance penalties and acoustic suppression characteristics. The tests demonstrate that translating centerbody and radial vane sonic inlets, and QCSEE high throat Mach number inlets, can be designed to operate effectively at forward speed and moderate angle of attack with good performance and noise suppression capability. The test equipment and procedures used in conducting the evaluation are described. Results of the tests are presented in tabular form
Magnetization vector in the reversible region of a highly anisotropic cuprate superconductor: anisotropy factor and the role of 2D vortex fluctuations
By using a high quality Tl2Ba2Ca2Cu3O10 (Tl-2223) single crystal as an
example, the magnetization vector was probed in the reversible region of highly
anisotropic cuprate superconductors. For that, we have measured its components
along and transverse to the applied magnetic field for different crystal
orientations. The analysis shows that the angular dependence of the
perpendicular component of the magnetization vector follows the one predicted
by a London-like approach which includes a contribution associated with the
thermal fluctuations of the 2D vortex positions. For the Tl-2223 crystal
studied here, a lower bound for the anisotropy factor was estimated to be about
190.Comment: 6 pages, 3 figure
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