2,946 research outputs found
Inequivalent Quantization in the Skyrme Model
Quantum mechanics on manifolds is not unique and in general infinite number
of inequivalent quantizations can be considered. They are specified by the
induced spin and the induced gauge structures on the manifold. The
configuration space of collective mode in the Skyrme model can be identified
with and thus the quantization is not unique. This leads to the
different predictions for the physical observables.Comment: 16 pages, LaTeX2
Current-driven vortex domain wall dynamics by micromagnetic simulations
Current-driven vortex wall dynamics is studied by means of a two-dimensional
analytical model and micromagnetic simulation. By constructing a trial function
for the vortex wall in the magnetic wire, we analytically solve for domain wall
velocity and deformation in the presence of the current-induced spin torque. A
critical current for the domain wall transformation from the vortex wall to the
transverse wall is calculated. A comparison between the field- and
current-driven wall dynamics is carried out. Micromagnetic simulations are
performed to verify our analytical results.Comment: 7 pages, 4 figure
Real-space observation of current-driven domain wall motion in submicron magnetic wires
Spintronic devices, whose operation is based on the motion of a magnetic
domain wall (DW), have been proposed recently. If a DW could be driven directly
by flowing an electric current instead of a magnetic field, the performance and
functions of such device would be drastically improved. Here we report
real-space observation of the current-driven DW motion by using a well-defined
single DW in a micro-fabricated magnetic wire with submicron width. Magnetic
force microscopy (MFM) visualizes that a single DW introduced in the wire is
displaced back and forth by positive and negative pulsed-current, respectively.
We can control the DW position in the wire by tuning the intensity, the
duration and the polarity of the pulsed-current. It is, thus, demonstrated that
spintronic device operation by the current-driven DW motion is possible.Comment: Accepted and published in PR
Validation and clinical application of novel coronary imaging methods to assess metallic or bioresorbable coronary stents
Long-term follow-up of atrial contraction following the maze procedure in patients with mitral valvular disease
Development of nickel-metal hydride cell: An update
This paper presents in viewgraph format an overview of NASDA's evaluation of commercial nickel metal-hydride (Ni-MH) cells and the development and testing of Ni-MH cells for use in space. The commercial cells are concluded to be feasible and suitable for use in LEO; for GEO, the durability for overcharge is needed because long-term charge retention is required. For the aerospace Ni-MH cell design, two activation procedures are applied to evaluate the effect of the difference in the amount of overcharge protection and precharge. Specific energy of the Ni-MH cell is nearly accomplished at 50 Wh/kg. Initial characteristics indicate the effect derived from precharge. Thirty-five amp-hour class Ni-MH cells have good performance for LEO cycle of 25 and 40 percent DOD up to 3000 cycles as similar to commercial cells. The effect of the difference in the amount of overcharge protection will appear in life test
Performance test results of ETS-6 Ni-Cd cells
The topics covered are presented in viewgraph form and include the following: development schedule; main specification; cell design; production flow; acceptance test (1); acceptance test (2); cell weight; 20 C performance; capacity; overcharge pressure; end of charge voltage; -5 C performance; ETS-VI simulation cycle test; and battery storage
Significance of myocardial tenascin-C expression in left ventricular remodelling and long-term outcome in patients with dilated cardiomyopathy
Aim Dilated cardiomyopathy (DCM) has a variety of causes, and no useful approach to predict left ventricular (LV) remodelling and long-term outcome has yet been established. Myocardial tenascin-C (TNC) is known to appear under pathological conditions, possibly to regulate cardiac remodelling. The aim of this study was to clarify the significance of myocardial TNC expression in LV remodelling and the long-term outcome in DCM. Methods and results One hundred and twenty-three consecutive DCM patients who underwent endomyocardial biopsy for initial diagnosis were studied. Expression of TNC in biopsy sections was analysed immunohistochemically to quantify the ratio of the TNC-positive area to the whole myocardial tissue area (TNC area). Clinical parameters associated with TNC area were investigated. The patients were divided into two groups based on receiver operating characteristic analysis of TNC area to predict death: high TNC group with TNC area ≥2.3% (22 patients) and low TNC group with TNC area <2.3% (101 patients). High TNC was associated with diabetes mellitus. Comparing echocardiographic findings between before and 9 months after endomyocardial biopsy, the low TNC group was associated with decreased LV end-diastolic diameter and increased LV ejection fraction, whereas the high TNC group was not. Survival analysis revealed a worse outcome in the high TNC group than in the low TNC group (P < 0.001). Multivariable Cox regression analysis revealed that TNC area was independently associated with poor outcome (HR = 1.347, P = 0.032). Conclusions Increased myocardial TNC expression was associated with worse LV remodeling and long-term outcome in DCM
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