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

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

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 Co$_2$MnSi deposited on (001) MgO with annealing temperatures ($T_A$). By increasing the $T_A$ from 300$^\circ$C to 600$^\circ$C, the film goes from a disordered nanocrystalline phase to $B2$ ordered and finally to the $L2_1$ ordered alloy. The saturation magnetic moment improves with structural ordering and approaches the Slater-Pauling value of $\approx 5.0 \mu_B$ per formula unit for $T_A$ = 600$^\circ$C. At this stage the films are soft magnets with coercive and saturation fields as low as $\approx$ 7 mT and 350 mT, respectively. Remarkable effects of improved structural order are also seen in longitudinal resistivity ($\rho_{xx}$) and residual resistivity ratio. A model based upon electronic transparency of grain boundaries illucidates the transition from a state of negative $d\rho/dT$ to positive $d\rho/dT$ with improved structural order. The Hall resistivity ($\rho_{xy}$) 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 ($n$) and mobility ($\mu$) have been extracted from the high field $\rho_{xy}$ data. The highly ordered films are characterized by $n$ and $\mu$ of 1.19$\times$ 10$^{29}$ m$^{-3}$ and 0.4 cm$^2V^{-1}s^{-1}$ at room temperature. The dependence of $\rho_{xy}$ on $\rho_{xx}$ indicates the dominance of skew scattering in our films, which shows a monotonic drop on raising the $T_A$. The topological Hall effect is analyzed for the films annealed at 300$^\circ$C. ......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