Soliton transmission through disordered system

An exact formula for the transmission time in the disordered nonlinear soliton-bearing classical one-dimensional system is obtained

Technical solutions for the transmission of electricity at high voltage in arctic conditions

The article considers the main solutions to the problems that arise during the transmission of high voltage electricity in the Far North. The relevance of this topic is associated with the high strategic importance of the Arctic zone for the Russian Federation and ensuring national security for the period up to 2035. Within the framework of this strategy, it is necessary to develop and implement engineering and technical solutions for the transmission of electric power that ensure the stable functioning of the infrastructure in extreme climatic conditions. An analysis of existing solutions for the transmission of electricity in the Arctic zone was carried out. For overhead and cable power lines, their design features, their operating conditions, as well as the features of laying at extremely low temperatures are described. Within the framework of this work, the prerequisites for the use of gas-insulated lines, as well as conductors with cast insulation, are put forward. The main advantages and disadvantages of using the considered equipment are determined. Further exploration and development of the Arctic zone will dictate more stringent requirements for the equipment used. So, in order to reduce dielectric losses during the transmission of electricity, the authors propose the use of a promising polymer-gas conductor, which can be operated both in air and in water. Numerical analysis of reduction of dielectric losses and values of electric field strength in a polymer-gas conductor in comparison with existing solutions has been carried out

Multifrequency variability of the blazar AO 0235+164 the WEBT campaign in 2004-2005 and long-term SED analysis

A huge multiwavelength campaign targeting the blazar AO 0235+164 was organized by the Whole Earth Blazar Telescope (WEBT) in 2003-2005 to study the variability properties of the source. Monitoring observations were carried out at cm and mm wavelengths, and in the near-IR and optical bands, while three pointings by the XMM-Newton satellite provided information on the X-ray and UV emission. We present the data acquired during the second observing season, 2004-2005, by 27 radio-to-optical telescopes. They reveal an increased near-IR and optical activity with respect to the previous season. Increased variability is also found at the higher radio frequencies, down to 15 GHz, but not at the lower ones. The radio (and optical) outburst predicted to peak around February-March 2004 on the basis of the previously observed 5-6 yr quasi-periodicity did not occur. The analysis of the optical light curves reveals now a longer characteristic time scale of 8 yr, which is also present in the radio data. The spectral energy distributions corresponding to the XMM-Newton observations performed during the WEBT campaign are compared with those pertaining to previous pointings of X-ray satellites. Bright, soft X-ray spectra can be described in terms of an extra component, which appears also when the source is faint through a hard UV spectrum and a curvature of the X-ray spectrum. Finally, there might be a correlation between the X-ray and optical bright states with a long time delay of about 5 yr, which would require a geometrical interpretation

White Matter Lesion Segmentation from Volumetric MR Images

Abstract. White matter lesions are common pathological findings in MR tomograms of elderly subjects. These lesions are typically caused by small vessel diseases (e.g., due to hypertension, diabetes). In this paper, we introduce an automatic algorithm for segmentation of white matter lesions from volumetric MR images. In the literature, there are methods based on multi-channel MR images, which obtain good results. But they assume that the different channel images have same resolution, which is often not available. Although our method is also based on T1 and T2 weighted MR images, we do not assume that they have the same resolution (Generally, the T2 volume has much less slices than the T1 volume). Our method can be summarized as the following three steps: 1) Register the T1 image volume and the T2 image volume to find the T1 slices corresponding to those in the T2 volume; 2) Based on the T1 and T2 image slices, lesions in these slices are segmented; 3) Use deformable models to segment lesion boundaries in those T1 slices, which do not have corresponding T2 slices. Experimental results demonstrate that our algorithm performs well.