Glacifluviálně-glacilakustrinní sekvence u Vidnavy na severním okraji Žulovské pahorkatiny

Glaciofluvial and glaciolacustrine sediments were discovered in a small sandpit situated 800 m SE from Vindava (the Polský kopec Site). Sediments fill two channels located in superposition. Three facies associations (FA) were distinguished in this sedimentary section. The base of the lower channel is formed by gravel lag overlain by gravel-sandy sediments of 3-D dunes and a side bar (FA1). The upper channel infill begins also by basal lag and grades to a fining-upwards sequence from sand to silt (FA2). The sequence is formed from the base up by sediments of small 3-D dunes, A-type ripples, B-type ripples, C-type ripples, and horizontally laminated sediments. The sequence reveals a vertical transition from glaciofluvial (sand) to glaciolacustrine (silt) sedimentation. The sedimentary section is terminated by flat glaciofluvial bedforms (FA3) deposited under upper plane bed conditions. These bedforms arose after the restoration of glaciofluvial conditions. The base of the glaciolacustrine sequence is located at an altitude of ~ 275 m as well as the Old Kaolin Mine Site (850 m SW from the Polský kopec Site) where very similar sediments have been already described. The sediments of both localities represent a proglacial outwash plain in front of the retreating ice sheet (FA1 consists of ~ 23% of erratic rocks), where a relatively large lake, or a system of smaller lakes evolved at the same time.

High selectivity wideband 180° phase shifters with the functionality of vertical transition

In this paper, a high selectivity wideband 180° phase shifter (PS) with the functionality of vertical transition is presented. The whole circuit is realized based on the hybrid microstrip/slotline (SL) structure. By introducing the short-circuited microstrip stepped-impedance resonators, two transmission zeros are created to improve the selectivity of the PS. With the SL in the center ground layer, a frequency independent 180° PS can be obtained. The even/odd-mode equivalent circuits of the proposed PS are analyzed to guide the design. Finally, a practical wideband 180° PS with high filtering selectivity is designed and fabricated to verify the design theory.

Relation Between Image Quality and Scan Resolution: Part I

Currently, a particular scan resolution has to be defined before a scanner starts working. Two problems arise from this process. Firstly, no matter how different two pages contents are, they will be scanned into the same resolution. For example, after scanning, a blank page and a fine-detailed drawing will have the same resolution. Secondly, for one scanned page, every part of its output would have the same resolution, whatever their contents are. These problems will cause unnecessary waste of memory used to store scanned images. So a method to decide the minimum acceptable scan resolution is needed. But current image quality estimators are not suitable for estimating image quality at different resolutions. This paper proposes four features to assess image qualities at different resolutions, namely 75, 100, 150, 200 and 300 dpi. The features are tile-SSIM mean, tile-SSIM standard deviation, horizontal transition density, and vertical transition density. Tests on images containing different contents show that these features are promising in evaluate image qualities across different scan resolutions.