high purity fluorapatite (fa) with rod-like and spherical-like morphology was synthesized via sol-gel method. chemical characterization of fa powders was done by xrd and ftir analyses. crystallite samples were calculated using scherer method. morphology of fa powders was investigated with tem and sem images. the results revealed that increasing the time of hydrolysis of phosphate sols significa...

The bridge index and superbridge index of a knot are important invariants in knot theory. We define the bridge map of a knot conformation, which is closely related to these two invariants, and interpret it in terms of the tangent indicatrix of the knot conformation. Using the concepts of dual and derivative curves of spherical curves as introduced by Arnold, we show that the graph of the bridge...

We propose Möbius transformations as the natural rotation and scaling tools for editing spherical images. As an application we produce spherical Droste images. We obtain other self-similar visual effects using rational functions, elliptic functions, and Schwarz-Christoffel maps.

PURPOSE To evaluate clinical characteristics and the macular gradient in myopic posterior staphyloma with time domain (TD) optical coherence tomography (OCT). METHODS Sixty-four staphyloma eyes of 40 patients were examined. Macular gradient (tangent θ) and the location of staphyloma were assessed with OCT imaging. The macular gradient was measured at points 1 mm and 2 mm distant from the fove...

In this paper we consider 4-dimensional steady soliton singularity models, i.e., complete gradient Ricci solitons that arise as the rescaled limit of a finite time singular solution flow on closed 4-manifold. particular, study geometry at infinity such under assumption their tangent is product R with 3-dimensional spherical space form. We also classify flows models in general.

This paper considers the problem of shape-based recognition and pose estimation of 3-D free-form objects in scenes that contain occlusion and clutter. Our approach is based on a novel set of discriminating descriptors called spherical spin images, which encode the shape information conveyed by classes of distributions of surface points constructed with respect to reference points on the surface...

We propose a semi-automatic omnidirectional texturing method that maps a spherical image onto a dense 3D model obtained by a range sensor. For accurate texturing, accurate estimation of the extrinsic parameters is inevitable. In order to estimate these parameters, we propose a robust 3D registration-based method between a dense range data set and a sparse spherical image stereo data set. For me...

Fisheye lenses are often used to enlarge the field of view (FOV) of a conventional camera. But the images taken with fisheye lenses have severe distortions. This paper proposes a novel calibration method for fisheye lenses using images of space lines in a single fisheye image. Since some fisheye cameras’ FOV are around 180 degrees, the spherical perspective projection model is employed. It is w...