introduction: the different factors that affect the camera uniformity of single photon emission computed tomography (spect) technique have been analyzed including peak shift (%) and window width of energy. the effect of peak shift and window width on spect image uniformity has been investigated using a point source to perform intrinsic flood images. methods:the relation between calculated integ...

The development and application of a geometrically-based uniformity criterion is presented for film uniformity optimization in a radial-flow GaN epitaxy reactor system. In this multi-wafer reactor system, individual wafers rotate on a rotating susceptor in a planetary motion to reduce the effects of reactant depletion on deposition uniformity; the uniformity criterion developed for this system ...

Introduction Signal intensity uniformity in a magnetic resonance (MR) image indicates how well the MR imaging (MRI) system represents an object. One of the major sources of image non-uniformity in high-field MRI scanners is inhomogeneity of radio-frequency coil. The aim of this study was to investigate non-uniformity in head, head and neck, and body coils and compare the obtained results to det...

We study the problem of generalized uniformity testing [BC17] of a discrete probability distribution: Given samples from a probability distribution p over an unknown discrete domain Ω, we want to distinguish, with probability at least 2/3, between the case that p is uniform on some subset of Ω versus -far, in total variation distance, from any such uniform distribution. We establish tight bound...

We introduce new necessary conditions, k-quasi-hamiltonicity (0 k n ? 1), for a digraph of order n to be hamiltonian. Every (k + 1)-quasi-hamiltonian digraph is also k-quasi-hamiltonian; we construct digraphs which are k-quasi-hamiltonian, but not (k + 1)-quasi-hamiltonian. We design an algorithm that checks k-quasi-hamiltonicity of a given digraph with n vertices and m arcs in time O(nm k). We...

Due to their well-defined three-dimensional geometry, spiro compounds are widely utilized in drug research. From the central tetrahedral carbon atom, besides the regular structure, an inverted spiro connectivity may be envisioned. Here we disclose the synthesis of this molecule class that we have coined quasi[1]catenanes. Next to their fascinating and aesthetic shape, the higher compactness as ...

the effects of priming treatment using five osmotic solutions (peg, manitol, kno3, kh2po4 and combination of two salts) in six osmotic potentials (-1 to -1.5 mpa) was studied on germination percentage, rate and uniformity of melon seeds. the best results were obtained with high concentrations of kno3 and lower concentrations of manitol. mean germination time of melon seeds in 19°c was preceeded...