22,465 research outputs found
INTRINSIC DEFECT ENERGIES OF LITHIUM HYDRIDE AND LITHIUM DEUTERIDE CRYSTALS
A theoretical study has been made of the defect structure of lithium hydride and lithium deuteride. A potential model is obtained describing the statics and dynamics of these crystals. Intrinsic defect energies are calculated using the Harwell HADES program which is based on a generalised Mott-Littleton method. The results are in good agreement with the experimental data, and suggest that the vacancy and interstitial migration mechanisms of anions and cations are all comparable in their contribution to ionic conduction
Operational Trans-Resistance Amplifier Based Tunable Wave Active Filter
In this paper, Operational Trans-Resistance Amplifier (OTRA) based wave active filter structures are presented. They are flexible and modular, making them suitable to implement higher order filters. The circuits implement the resistors using matched transistors, operating in linear region, making them well suited for IC fabrication. They are insensitive to parasitic input capacitances and input resistances due to the internally grounded input terminals of OTRA. As an application, a doubly terminated third order Butterworth low pass filter has been implemented, by substituting OTRA based wave equivalents of passive elements. PSPICE simulations are given to verify the theoretical analysis
Structural ordering driven anisotropic magnetoresistance, anomalous Hall resistance and its topological overtones in full-Heusler Co2MnSi thin films
We report the evolution of crystallographic structure, magnetic ordering and
electronic transport in thin films of full-Heusler alloy CoMnSi deposited
on (001) MgO with annealing temperatures (). By increasing the from
300C to 600C, the film goes from a disordered nanocrystalline
phase to ordered and finally to the ordered alloy. The saturation
magnetic moment improves with structural ordering and approaches the
Slater-Pauling value of per formula unit for =
600C. At this stage the films are soft magnets with coercive and
saturation fields as low as 7 mT and 350 mT, respectively. Remarkable
effects of improved structural order are also seen in longitudinal resistivity
() and residual resistivity ratio. A model based upon electronic
transparency of grain boundaries illucidates the transition from a state of
negative to positive with improved structural order. The
Hall resistivity () derives contribution from the normal scattering
of charge carriers in external magnetic field, the anomalous effect originating
from built-in magnetization and a small but distinct topological Hall effect in
the disordered phase. The carrier concentration () and mobility () have
been extracted from the high field data. The highly ordered films
are characterized by and of 1.19 10 m and 0.4
cm at room temperature. The dependence of on
indicates the dominance of skew scattering in our films, which
shows a monotonic drop on raising the . The topological Hall effect is
analyzed for the films annealed at 300C. ......Comment: 10 pages, 9 figures, 1 tabl
A Ballistic Graphene Cooper Pair Splitter
We report an experimental study of Cooper pair splitting in an encapsulated
graphene based multiterminal junction in the ballistic transport regime. Our
device consists of two transverse junctions, namely the
superconductor/graphene/superconductor and the normal metal/graphene/normal
metal junctions. In this case, the electronic transport through one junction
can be tuned by an applied bias along the other. We observe clear signatures of
Cooper pair splitting in the local as well as nonlocal electronic transport
measurements. Our experimental data can be very well described by using a
modified Octavio-Tinkham-Blonder-Klapwijk model and a three-terminal beam
splitter model
Robust and Fast 3D Scan Alignment using Mutual Information
This paper presents a mutual information (MI) based algorithm for the
estimation of full 6-degree-of-freedom (DOF) rigid body transformation between
two overlapping point clouds. We first divide the scene into a 3D voxel grid
and define simple to compute features for each voxel in the scan. The two scans
that need to be aligned are considered as a collection of these features and
the MI between these voxelized features is maximized to obtain the correct
alignment of scans. We have implemented our method with various simple point
cloud features (such as number of points in voxel, variance of z-height in
voxel) and compared the performance of the proposed method with existing
point-to-point and point-to- distribution registration methods. We show that
our approach has an efficient and fast parallel implementation on GPU, and
evaluate the robustness and speed of the proposed algorithm on two real-world
datasets which have variety of dynamic scenes from different environments
- …