Coordinates: 59°58′21″N 30°19′21″E / 59.97250°N 30.32250°E / 59.97250; 30.32250Saint Petersburg Electrotechnical University "LETI" (ETU, ETU "LETI", Russian: Санкт-Петербургский государственный электротехнический университет «ЛЭТИ» им. В.И. Ульянова (Ленина), СПбГЭТУ «ЛЭТИ») is a public university and one of the oldest Russian higher education institutions.It was founded in 1886 as a Technical College. LETI, as it is popularly called, received the status of a higher education institution in 1899 and became known as Electrotechnical Institute. ETU was the first higher educational institution in Europe to specialize in electrical engineering. In August 2016 ETU “LETI” became the part of the Project 5-100, a Russian academic excellence program.The University has training programs in fields of radio engineering, telecommunications, control processes, computer engineering and IT, electronics, biomedical engineering, management, and linguistics.
A method for noncoherent reception of signals in a fast fading channel is proposed. The algorithm does not require channel state estimation, it implements generalized likelihood ratio test for the case of Rayleigh channel with correlation properties known at the receiving side. The resulting receiver structure requires calculating several correlations for each possible transmitted signal and then combining the results. Computer simulations have shown that the proposed algorithm can work in fast fading conditions, significantly reducing receiver sensitivity to Doppler spread.
A system with three or more components (n ⩾ 3) is quasi-simple if the isotherms–isobars–isopotentials of the system’s components (the solvents of solubility diagrams) are line segments (n = 3), sectors of planes (n = 4), or hyperplanes (n ⩾ 5). This work presents evidence that all figurative points on monovariant branches of the joint crystallization of two identical solid phases in different quasi-simple quaternary systems (n = 4) (with two identical and one different component) belong to a single curve. Systems of equations are given for thermodynamic calculations of such curves exclusively from data on binary subsystems. Examples of calculating these monovariant curves are provided, and agreement is shown between non-model calculations and experimental data on the compositions of saturated solutions using quaternary systems with a common cation, a common anion, and quaternary reciprocal systems as examples. Agreement is also seen between results from thermodynamic calculations and numerous experimental data. The results can naturally be extended to monovariant crystallization lines of three or more identical solid phases on the solubility diagrams of quasi-simple systems with five or more components (and one that is different).
Accelerators of negative hydrogen ions and deuterons are widely used, for example, in the field of medicine. The particle beam is removed from the accelerators by recharging ions as they pass through a thin carbon foil. The paper presents the results of a study of the longevity of stripper foils. Carbon foils with a thickness of 1 – 4 μm obtained on a glass substrate by vacuum arc sputtering of graphite rods were studied. During the experiments, a laboratory setup was used that simulates the effect of a beam of negative hydrogen ions (energy 18 MeV) using an electron beam (energy 10 keV). The samples were irradiated with a stream of electrons, while each sample retained its integrity. Before and after irradiation, the foil surfaces were analyzed using atomic force microscopy. It was found that irradiation changes the morphology of the surface (roughness parameters deteriorate). The method of electrostatic force microscopy revealed a noticeable difference between the irradiated and non-irradiated parts of the foil not only in thickness, but also in electrical conductivity. The obtained results and the developed research method can be used for prompt changes to the foil forming technology to increase their service life.
The geometry of a plasma microwave resonator for CVD diamond growth technology was calculated using the Comsol package, which provides the growth of both an undoped diamond in the TM mode and of the doping δ layer in the TE mode. It is shown that sufficiently homogeneous plasma over the diamond growth surface (substrate) can be maintained in the TE mode at a low gas pressure that is optimal for growing the δ layer. The main trends predicted by the simple calculation model developed in the first part of the present communication, in particular, sufficiently high electron temperature and plasma density when using the low-pressure TE mode, are confirmed.
This paper presents the results of a study of the toxicity of high-silica quartzoid glasses (QGs) containing cesium, obtained on the basis of two-phase alkali borosilicate glass. It is established that the toxicity of the studied QGs in relation to Paramecium caudatum does not exceed the permissible level and varies depending on the content of alkaline ions in the QG and the time of contact of fine QG powder with water. It is assumed that the identified toxicity is associated primarily with the extraction of sodium and cesium ions into the aqueous solution.
