139 research outputs found
NEAR THE ORIGINS OF MILLIMETER WAVE RADAR (90-th anniversary of Vadym Π. Razskazovsky)
This paper is dedicated to the 90-th anniversary of Vadym Borysovych Razskazovsky, an outstanding scientist in the fields of radio engineering and radio science, holder of the titles and positions like DSc (Engineering), Professor, and Head of the Statistical radio physics department at the O.Ya. Usikov Institute for Radio Physics and Electronics within the Academy of Sciences of Ukraine
Improving the quality of products created by additive technologies on the basis of tig welding
Π ΡΠΎΠ±ΠΎΡΡ ΡΠΎΠ·Π³Π»ΡΠ΄Π°ΡΡΡΡΡ ΠΏΠΈΡΠ°Π½Π½Ρ ΠΎΡΡΠΈΠΌΠ°Π½Π½Ρ ΠΌΡΠ½ΡΠΌΠ°Π»ΡΠ½ΠΎΡ Ρ
Π²ΠΈΠ»ΡΡΡΠΎΡΡΡ ΠΏΠΎΠ²Π΅ΡΡ
ΠΎΠ½Ρ, ΡΠΎ ΡΠΎΡΠΌΡΡΡΡΡΡ Π°Π΄Π΄ΠΈΡΠΈΠ²Π½ΠΈΠΌ ΠΏΡΠΎΡΠ΅ΡΠΎΠΌ Π°ΡΠ³ΠΎΠ½Π½ΠΎ-Π΄ΡΠ³ΠΎΠ²ΠΎΠ³ΠΎ Π·Π²Π°ΡΡΠ²Π°Π½Π½Ρ. ΠΡΠ΄ΠΎΠΌΠΎ, ΡΠΎ Π³Π΅ΠΎΠΌΠ΅ΡΡΠΈΡΠ½Ρ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΈ Π²Π°Π»ΠΈΠΊΠ° ΡΠΎΠ·ΠΏΠ»Π°Π²Ρ, ΡΠΎ ΠΏΠΎΡΠ°ΡΠΎΠ²ΠΎ ΡΠΎΡΠΌΡΡ Π²ΡΠ΄ΡΠ²ΠΎ-ΡΡΠ²Π°Π½Ρ Π·Π°Π³ΠΎΡΠΎΠ²ΠΊΡ, Π²ΠΈΠ·Π½Π°ΡΠ°ΡΡΡΡΡ ΡΠΊ Π΅Π½Π΅ΡΠ³Π΅ΡΠΈΡΠ½ΠΈΠΌΠΈ, ΡΠ°ΠΊ Ρ ΠΊΡΠ½Π΅ΠΌΠ°ΡΠΈΡΠ½ΠΈΠΌΠΈ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠ°ΠΌΠΈ ΠΏΡΠΎΡΠ΅ΡΡ. ΠΡΠΈ ΡΡΠΎΠΌΡ Π²ΠΈΠΊΠ»Π°Π΄Π°Π½Π½Ρ Π²Π°Π»ΠΈΠΊΡΠ² Π²ΡΠ΄Π±ΡΠ²Π°ΡΡΡΡΡ Π· ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΠΈΠΌ ΠΏΠ΅ΡΠ΅ΠΊΡΠΈΡΡΡΠΌ, Π·Π°Π²Π΄ΡΠΊΠΈ ΡΠΎΠΌΡ Π²Π΄Π°ΡΡΡΡΡ Π΄ΠΎΡΡΠ³ΡΠΈ ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΡ ΡΡΠ»ΡΠ½ΠΎΡΡΡ ΠΌΠΎΠ΄Π΅Π»Ρ, ΠΎΠ΄Π½Π°ΠΊ Π· ΠΎΠ΄Π½ΠΎΡΠ°ΡΠ½ΠΈΠΌ Π²ΠΈΠ½ΠΈΠΊΠ½Π΅Π½Π½ΡΠΌ ΠΏΠ΅Π²Π½ΠΎΡ Ρ
Π²ΠΈΠ»ΡΡΡΠΎΡΡΡ, ΠΎΠ±ΡΠΌΠΎΠ²Π»Π΅Π½ΠΎΡ ΡΠ΅ΡΠΌΠΎΠ΄ΠΈΠ½Π°ΠΌΡΡΠ½ΠΈΠΌΠΈ ΡΠ²ΠΈΡΠ°ΠΌΠΈ Ρ Π²Π°Π½Π½Ρ ΡΠΎΠ·ΠΏΠ»Π°Π²Ρ. ΠΠ°ΠΏΡΠΎΠΏΠΎΠ½ΠΎΠ²Π°Π½Π° ΠΌΠΎΠ΄Π΅Π»Ρ ΡΠΎΡΠΌΡΠ²Π°Π½Π½Ρ Π²Π°Π»ΠΈΠΊΡ Π½Π°ΠΏΠ»Π°Π²Ρ, Π·Π°Π²Π΄ΡΠΊΠΈ ΡΠΊΡΠΉ Π²ΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΎ ΡΠ°ΡΡΠΎΠ½Π°Π»ΡΠ½Ρ ΡΠΌΠΎΠ²ΠΈ Π²ΠΈΠΊΠ»Π°Π΄Π°Π½Π½Ρ ΡΠ°ΡΡΠ². ΠΠ°Π²Π΅Π΄Π΅Π½ΠΎ Π΅ΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Π»ΡΠ½Ρ Π΄ΠΎΡΠ»ΡΠ΄ΠΆΠ΅Π½Π½Ρ ΠΏΡΠΎΡΠ΅ΡΡ Π°ΡΠ³ΠΎΠ½Π½ΠΎ-Π΄ΡΠ³ΠΎΠ²ΠΎΠ³ΠΎ Π²ΡΠ΄ΡΠ²ΠΎΡΠ΅Π½Π½Ρ ΠΌΠΎΠ΄Π΅Π»Π΅ΠΉ Π·Π°Π΄Π°Π½ΠΎΡ ΡΠΎΡΠΌΠΈ, ΠΎΡΡΠΈΠΌΠ°Π½ΠΎ ΡΠ΅Π³ΡΠ΅ΡΡΠΉΠ½Ρ ΡΡΠ²Π½ΡΠ½Π½Ρ Π΄Π»Ρ Π²ΠΈΠ·Π½Π°ΡΠ΅Π½Π½Ρ ΠΊΠΎΠ½ΡΡΠΎΠ»ΡΠΎΠ²Π°Π½ΠΎΠ³ΠΎ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΡ Ρ
Π²ΠΈΠ»ΡΡΡΠΎΡΡΡ. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΠΎ Π½Π° ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡ Ρ
Π²ΠΈΠ»ΡΡΡΠΎΡΡΡ Π²ΠΈΠΏΠ»ΠΈΠ²Π°ΡΡΡ Π΄ΠΈΠ½Π°ΠΌΡΡΠ½Ρ ΡΠ²ΠΈΡΠ° ΡΠ° Ρ
Π²ΠΈΠ»ΡΠΎΠ²Ρ ΠΏΡΠΎΡΠ΅ΡΠΈ, ΡΠΊΡ ΡΠΎΠ·Π²ΠΈΠ²Π°ΡΡΡΡΡ ΠΏΡΠ΄ Π΄ΡΡΡ ΡΠΈΡΡΠ΅ΠΌΠΈ ΡΠΈΠ» ΠΏΡΠ΄ ΡΠ°Ρ ΡΠΎΡΠΌΡΠ²Π°Π½Π½Ρ Π²Π°Π»ΠΈΠΊΡ Π½Π°ΠΏΠ»Π°Π²Ρ. ΠΠΎΠΊΡΠ°ΡΠ΅Π½Π½Ρ ΡΠΊΠΎΡΡΡ Π²ΠΈΡΠΎΠ±ΡΠ² Π²Π±Π°ΡΠ°ΡΡΡΡΡ Π² ΠΎΠΏΡΠΈΠΌΡΠ·Π°ΡΡΡ ΡΠΏΠΎΡΠΎΠ±ΡΠ² ΡΠΎΡΠΌΡΠ²Π°Π½Π½Ρ Π²Π°Π»ΠΈΠΊΡΠ², Π·Π°Π±Π΅Π·ΠΏΠ΅ΡΠ΅Π½Π½ΡΠΌ Π΄ΠΈΠ½Π°ΠΌΡΡΠ½ΠΎΡ ΡΡΠ°Π»ΠΎΡΡΡ ΡΡΡ
Ρ ΡΠΎΠ±ΠΎΡΠΎΡ Π³ΠΎΠ»ΠΎΠ²ΠΊΠΈ, Π·Π°Π±Π΅Π·ΠΏΠ΅ΡΠ΅Π½Π½ΡΠΌ Π²ΡΠ΄ΠΏΠΎΠ²ΡΠ΄Π½ΠΎΠ³ΠΎ ΠΏΠ΅ΡΠ΅ΠΊΡΠΈΡΡΡ ΡΡΠ°ΡΠΊΡΠΎΡΡΠΉ ΡΡΡ
Ρ ΠΏΠΎ ΡΠ°ΡΠ°ΠΌ Π²ΠΈΠΊΠ»Π°Π΄Π°Π½Π½Ρ Π½Π° Π²Π΅Π»ΠΈΡΠΈΠ½Ρ 0,5 Π΅, Π·Π°Π±Π΅Π·ΠΏΠ΅ΡΠ΅Π½Π½ΡΠΌ Π΄ΠΈΠ½Π°ΠΌΡΡΠ½ΠΎΡ ΡΡΠ°Π»ΠΎΡΡΡ ΡΡΡ
Ρ ΡΠΎΠ±ΠΎΡΠΎΡ Π³ΠΎΠ»ΠΎΠ²ΠΊΠΈ, Π²ΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½Π½ΡΠΌ ΡΠ°ΡΡΠΎΠ½Π°Π»ΡΠ½ΠΎΡ Π΄ΠΎΠ²ΠΆΠΈΠ½ΠΈ Π΄ΡΠ³ΠΈ, Π° ΡΠ°ΠΊΠΎΠΆ ΠΏΡΠ΄ΡΡΠΈΠΌΠ°Π½Π½ΡΠΌ ΡΠ΅ΠΆΠΈΠΌΡ Π΄ΠΈΠ½Π°ΠΌΡΡΠ½ΠΎΡ ΡΡΠ°Π»ΠΎΡΡΡ Π³ΠΎΡΡΠ½Π½Ρ Π΄ΡΠ³ΠΈ ΠΠΎΠ±ΡΠ΄ΠΎΠ²Π°Π½ΠΎ ΠΏΠΎΠ²Π΅ΡΡ
Π½Ρ Π²ΡΠ΄Π³ΡΠΊΡΠ² ΡΡΠ»ΡΠΎΠ²ΠΈΡ
ΡΡΠ½ΠΊΡΡΠΉ Π² ΠΏΠ»ΠΎΡΠΈΠ½Π°Ρ
ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΡΠ² Π²ΠΏΠ»ΠΈΠ²Ρ, ΡΠΊΡ Π΄ΠΎΠ·Π²ΠΎΠ»ΡΡΡΡΡΡ Π½Π°Π³Π»ΡΠ΄Π½ΠΎ ΠΏΡΠΎΡΠ»ΡΡΡΡΡΠ²Π°ΡΠΈ Π·Π°Π»Π΅ΠΆΠ½ΡΡΡΡ ΠΊΠΎΠ½ΡΡΠΎΠ»ΡΠΎΠ²Π°Π½ΠΈΡ
Π³Π΅ΠΎΠΌΠ΅ΡΡΠΈΡΠ½ΠΈΡ
ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΡΠ² ΡΠ²Π° Π²ΡΠ΄ ΠΎΠΊΡΠ΅ΠΌΠΈΡ
ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΡΠ² Π²ΠΏΠ»ΠΈΠ²Ρ.The paper deals with the issues of obtaining the minimum waviness of surfaces formed by additive processes of TIG welding. It is known that the geometric parameters of the melt bead, which form a reproducible workpiece layer by layer, are determined by both the energy and kinematic characteristics of the process. In this case, the laying of the rollers occurs with optimal overlap, as a result of which it is possible to achieve the maximum density of the model, however, with the simultaneous appearance of a certain waviness due to thermodynamic phenomena in the melt bath. The proposed model of the formation of a bead of melt, the use of which made it possible to establish the rational conditions for laying out the layers. Experimental studies of the process of argon-arc surfacing of models of a given, regression equations for determining the controlled waviness parameter are obtained. It is shown that the waviness parameter is influenced by dynamic phenomena and wave processes that develop under the action of a system of forces during the formation of a melt bead. An improvement in the quality of products is seen in the optimization of the methods of forming the rollers, in ensuring the dynamic stability of the movement of the working head, ensuring the appropriate overlap of the trajectories of movement along the layers of the layout by an amount of 0.5e, establishing a rational arc length, and maintaining the dynamic stability of the arc burning. The response surfaces of the objective functions in the planes of the process parameters are constructed, which provide a clear illus-tration of the dependence of the controlled geometric parameters on the welding modes.Π ΡΠ°Π±ΠΎΡΠ΅ ΡΠ°ΡΡΠΌΠ°ΡΡΠΈΠ²Π°ΡΡΡΡ Π²ΠΎΠΏΡΠΎΡΡ ΠΏΠΎΠ»ΡΡΠ΅Π½ΠΈΡ ΠΌΠΈΠ½ΠΈΠΌΠ°Π»ΡΠ½ΠΎΠΉ Π²ΠΎΠ»Π½ΠΈΡΡΠΎΡΡΠΈ ΠΏΠΎΠ²Π΅ΡΡ
Π½ΠΎΡΡΠ΅ΠΉ, ΡΠΎΡΠΌΠΈΡΡΠ΅ΠΌΠΎΠΉ Π°Π΄Π΄ΠΈΡΠΈΠ²Π½ΡΠΌΠΈ ΠΏΡΠΎΡΠ΅ΡΡΠ°ΠΌΠΈ Π°ΡΠ³ΠΎΠ½Π½ΠΎ-Π΄ΡΠ³ΠΎΠ²ΠΎΠΉ ΡΠ²Π°ΡΠΊΠΈ. ΠΠ·Π²Π΅ΡΡΠ½ΠΎ, ΡΡΠΎ Π³Π΅ΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΡ Π²Π°Π»ΠΈΠΊΠ° ΡΠ°ΡΠΏΠ»Π°Π²Π°, ΠΊΠΎΡΠΎΡΡΠΌΠΈ ΠΏΠΎΡΠ»ΠΎΠΉΠ½ΠΎ ΡΠΎΡΠΌΠΈΡΡΠ΅ΡΡΡ Π²ΠΎΡΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΠΈΠΌΠ°Ρ Π·Π°Π³ΠΎΡΠΎΠ²ΠΊΠ°, ΠΎΠΏΡΠ΅Π΄Π΅Π»ΡΡΡΡΡ ΠΊΠ°ΠΊ ΡΠ½Π΅ΡΠ³Π΅ΡΠΈΡΠ΅ΡΠΊΠΈΠΌΠΈ, ΡΠ°ΠΊ ΠΈ ΠΊΠΈΠ½Π΅ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΠΌΠΈ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠ°ΠΌΠΈ ΠΏΡΠΎΡΠ΅ΡΡΠ°. ΠΡΠΈ ΡΡΠΎΠΌ Π²ΡΠΊΠ»Π°Π΄ΠΊΠ° Π²Π°Π»ΠΈΠΊΠΎΠ² ΠΏΡΠΎΠΈΡΡ
ΠΎΠ΄ΠΈΡ Ρ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΡΠΌ ΠΏΠ΅ΡΠ΅ΠΊΡΡΡΠΈΠ΅ΠΌ, Π² ΡΠ»Π΅Π΄ΡΡΠ²ΠΈΠ΅ ΡΠ΅Π³ΠΎ ΡΠ΄Π°Π΅ΡΡΡ Π΄ΠΎΡΡΠΈΡΡ ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΠΎΠΉ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΠΈ ΠΌΠΎΠ΄Π΅Π»ΠΈ, ΠΎΠ΄Π½Π°ΠΊΠΎ Ρ ΠΎΠ΄Π½ΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΡΠΌ Π²ΠΎΠ·Π½ΠΈΠΊΠ½ΠΎΠ²Π΅Π½ΠΈΠ΅ΠΌ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Π½ΠΎΠΉ Π²ΠΎΠ»Π½ΠΈΡΡΠΎΡΡΠΈ, ΠΎΠ±ΡΡΠ»ΠΎΠ²Π»Π΅Π½Π½ΠΎΠΉ ΡΠ΅ΡΠΌΠΎΠ΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΈΠΌΠΈ ΡΠ²Π»Π΅Π½ΠΈΡΠΌΠΈ Π² Π²Π°Π½Π½Π΅ ΡΠ°ΡΠΏΠ»Π°Π²Π°. ΠΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Π½Π°Ρ ΠΌΠΎΠ΄Π΅Π»Ρ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π²Π°Π»ΠΈΠΊΠ° ΡΠ°ΡΠΏΠ»Π°Π²Π°, ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ ΠΊΠΎΡΠΎΡΠΎΠΉ ΠΏΠΎΠ·Π²ΠΎΠ»ΠΈΠ»ΠΎ ΡΡΡΠ°Π½ΠΎΠ²ΠΈΡΡ ΡΠ°ΡΠΈΠΎΠ½Π°Π»ΡΠ½Ρ ΡΡΠ»ΠΎΠ²ΠΈΡ Π²ΡΠΊΠ»Π°Π΄ΠΊΠΈ ΡΠ»ΠΎΠ΅Π². ΠΡΠΈΠ²Π΅Π΄Π΅Π½Ρ ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΡΠ΅ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΠΏΡΠΎΡΠ΅ΡΡΠ° Π°ΡΠ³ΠΎΠ½Π½ΠΎ-Π΄ΡΠ³ΠΎΠ²ΠΎΠΉ Π½Π°ΠΏΠ»Π°Π²ΠΊΠΈ ΠΌΠΎΠ΄Π΅Π»Π΅ΠΉ Π·Π°Π΄Π°Π½Π½ΠΎΠΉ ΡΠΎΡΠΌΡ, ΠΏΠΎΠ»ΡΡΠ΅Π½Ρ ΡΠ΅Π³ΡΠ΅ΡΡΠΈΠΎΠ½Π½ΡΠ΅ ΡΡΠ°Π²Π½Π΅Π½ΠΈΡ Π΄Π»Ρ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΠΊΠΎΠ½ΡΡΠΎΠ»ΠΈΡΡΠ΅ΠΌΠΎΠ³ΠΎ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠ° Π²ΠΎΠ»Π½ΠΈΡΡΠΎΡΡΠΈ. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ Π½Π° ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡ Π²ΠΎΠ»Π½ΠΈΡΡΠΎΡΡΠΈ Π²Π»ΠΈΡΡΡ Π΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΡΠ²Π»Π΅Π½ΠΈΡ ΠΈ Π²ΠΎΠ»Π½ΠΎΠ²ΡΠ΅ ΠΏΡΠΎΡΠ΅ΡΡΡ, ΠΊΠΎΡΠΎΡΡΠ΅ ΡΠ°Π·Π²ΠΈΠ²Π°ΡΡΡΡ ΠΏΠΎΠ΄ Π΄Π΅ΠΉΡΡΠ²ΠΈΠ΅ΠΌ ΡΠΈΡΡΠ΅ΠΌΡ ΡΠΈΠ» ΠΏΡΠΈ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΠΈ Π²Π°Π»ΠΈΠΊΠ° ΡΠ°ΡΠΏΠ»Π°Π²Π°. Π£Π»ΡΡΡΠ΅Π½ΠΈΠ΅ ΠΊΠ°ΡΠ΅ΡΡΠ²Π° ΠΈΠ·Π΄Π΅Π»ΠΈΠΉ Π²ΠΈΠ΄ΠΈΡΡΡ Π² ΠΎΠΏΡΠΈΠΌΠΈΠ·Π°ΡΠΈΠΈ ΡΠΏΠΎΡΠΎΠ±ΠΎΠ² ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π²Π°Π»ΠΈΠΊΠΎΠ², Π² ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠ΅Π½ΠΈΠΈ Π΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΡΡΠΎΠΉΡΠΈΠ²ΠΎΡΡΠΈ Π΄Π²ΠΈΠΆΠ΅Π½ΠΈΡ ΡΠ°Π±ΠΎΡΠ΅ΠΉ Π³ΠΎΠ»ΠΎΠ²ΠΊΠΈ, ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠ΅Π½ΠΈΠ΅ΠΌ ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΡΡΡΠ΅Π³ΠΎ ΠΏΠ΅ΡΠ΅ΠΊΡΡΡΠΈΡ ΡΡΠ°Π΅ΠΊΡΠΎΡΠΈΠΉ Π΄Π²ΠΈΠΆΠ΅Π½ΠΈΡ ΠΏΠΎ ΡΠ»ΠΎΡΠΌ Π²ΡΠΊΠ»Π°Π΄ΠΊΠΈ Π½Π° Π²Π΅Π»ΠΈΡΠΈΠ½Ρ 0,5Π΅, ΡΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΈΠ΅ΠΌ ΡΠ°ΡΠΈΠΎΠ½Π°Π»ΡΠ½ΠΎΠΉ Π΄Π»ΠΈΠ½Ρ Π΄ΡΠ³ΠΈ, Π° ΡΠ°ΠΊΠΆΠ΅ ΠΏΠΎΠ΄Π΄Π΅ΡΠΆΠ°Π½ΠΈΠ΅ΠΌ ΡΠ΅ΠΆΠΈΠΌΠ° Π΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΡΡΠΎΠΉΡΠΈΠ²ΠΎΡΡΠΈ Π³ΠΎΡΠ΅Π½ΠΈΡ Π΄ΡΠ³ΠΈ. ΠΠΎΡΡΡΠΎΠ΅Π½ΠΎ ΠΏΠΎΠ²Π΅ΡΡ
Π½ΠΎΡΡΠΈ ΠΎΡΠΊΠ»ΠΈΠΊΠ° ΡΠ΅Π»Π΅Π²ΡΡ
ΡΡΠ½ΠΊΡΠΈΠΉ Π² ΠΏΠ»ΠΎΡΠΊΠΎΡΡΡΡ
ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² ΠΏΡΠΎΡΠ΅ΡΡΠ°, ΠΊΠΎΡΠΎΡΡΠ΅ Π΄Π°ΡΡ Π½Π°Π³Π»ΡΠ΄Π½ΡΡ ΠΈΠ»Π»ΡΡΡΡΠ°ΡΠΈΡ Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ ΠΊΠΎΠ½ΡΡΠΎΠ»ΠΈΡΡΠ΅ΠΌΡΡ
Π³Π΅ΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² ΠΎΡ ΡΠ΅ΠΆΠΈΠΌΠΎΠ² ΡΠ²Π°ΡΠΊΠΈ
Objectives of the Millimetron Space Observatory science program and technical capabilities of its realization
We present the scientific program of the Spectr-M project aimed at the creation and operation of the Millimetron Space Observatory (MSO) planned for launch in the late 2020s. The unique technical capabilities of the observatory will enable broadband observations of astronomical objects from 50 ΞΌm to 10 mm wavelengths with a record sensitivity (up to ~ 0.1 ΞΌJy) in the single-dish mode and with an unprecedented high angular resolution (~ 0.1 ΞΌas) in the ground-space very long baseline interferometer (SVLBI) regime. The program addresses fundamental priority issues of astrophysics and physics in general that can be solved only with the MSO capabilities: 1) the study of physical processes in the early Universe up to redshifts z ~ 2 Γ 106 through measuring ΞΌ-distortions of the cosmic microwave background (CMB) spectrum, and investigation of the structure and evolution of the Universe at redshifts z < 15 by measuring y-distortions of the CMB spectrum; 2) the investigation of the geometry of space-time around supermassive black holes (SMBHs) in the center of our Galaxy and M87 by imaging surrounding shadows, the study of plasma properties in the shadow formation regions, and the search for observational manifestations of wormholes; 3) the study of observational manifestations of the origin of life in the Universe - the search for water and biomarkers in the Galactic interstellar medium. Moreover, the technical capabilities of the MSO can help solve related problems, including the birth of the first galaxies and SMBHs (z β³ 10), alternative approaches to measuring the Hubble constant, the physics of SMBHs in 'dusty' galactic nuclei, the study of protoplanetary disks and water transport in them, and the study of 'ocean worlds' in the Solar System
Varespladib and cardiovascular events in patients with an acute coronary syndrome: the VISTA-16 randomized clinical trial
IMPORTANCE: Secretory phospholipase A2(sPLA2) generates bioactive phospholipid products implicated in atherosclerosis. The sPLA2inhibitor varespladib has favorable effects on lipid and inflammatory markers; however, its effect on cardiovascular outcomes is unknown. OBJECTIVE: To determine the effects of sPLA2inhibition with varespladib on cardiovascular outcomes. DESIGN, SETTING, AND PARTICIPANTS: A double-blind, randomized, multicenter trial at 362 academic and community hospitals in Europe, Australia, New Zealand, India, and North America of 5145 patients randomized within 96 hours of presentation of an acute coronary syndrome (ACS) to either varespladib (n = 2572) or placebo (n = 2573) with enrollment between June 1, 2010, and March 7, 2012 (study termination on March 9, 2012). INTERVENTIONS: Participants were randomized to receive varespladib (500 mg) or placebo daily for 16 weeks, in addition to atorvastatin and other established therapies. MAIN OUTCOMES AND MEASURES: The primary efficacy measurewas a composite of cardiovascular mortality, nonfatal myocardial infarction (MI), nonfatal stroke, or unstable angina with evidence of ischemia requiring hospitalization at 16 weeks. Six-month survival status was also evaluated. RESULTS: At a prespecified interim analysis, including 212 primary end point events, the independent data and safety monitoring board recommended termination of the trial for futility and possible harm. The primary end point occurred in 136 patients (6.1%) treated with varespladib compared with 109 patients (5.1%) treated with placebo (hazard ratio [HR], 1.25; 95%CI, 0.97-1.61; log-rank P = .08). Varespladib was associated with a greater risk of MI (78 [3.4%] vs 47 [2.2%]; HR, 1.66; 95%CI, 1.16-2.39; log-rank P = .005). The composite secondary end point of cardiovascular mortality, MI, and stroke was observed in 107 patients (4.6%) in the varespladib group and 79 patients (3.8%) in the placebo group (HR, 1.36; 95% CI, 1.02-1.82; P = .04). CONCLUSIONS AND RELEVANCE: In patients with recent ACS, varespladib did not reduce the risk of recurrent cardiovascular events and significantly increased the risk of MI. The sPLA2inhibition with varespladib may be harmful and is not a useful strategy to reduce adverse cardiovascular outcomes after ACS. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01130246. Copyright 2014 American Medical Association. All rights reserved
Clinical guidelines for the diagnosis and treatment of patients with irritable bowel syndrome
Objectives of the Millimetron Space Observatory Science Program and Technical Capabilities of Its Realization
We present the scientific program of the Spectr-M project aimed at the creation and operation of the Millimetron Space Observatory (MSO) planned for launch in the late 2020s. The unique technical capabilities of the observatory will enable broadband observations of astronomical objects from 50 ΞΌm to 10 mm wavelengths with a record sensitivity (up to βΌ0.1 ΞΌJy) in the single-dish mode and with an unprecedented high angular resolution (βΌ0.1 ΞΌas) in the ground-space very long baseline interferometer (SVLBI) regime. The program addresses fundamental priority issues of astrophysics and physics in general that can be solved only with the MSO capabilities: 1) the study of physical processes in the early Universe up to redshifts z βΌ 2 106 through measuring ΞΌ-distortions of the cosmic microwave background (CMB) spectrum, and investigation of the structure and evolution of the Universe at redshifts z<15 by measuring y-distortions of the CMB spectrum; 2) the investigation of the geometry of space-time around supermassive black holes (SMBHs) in the center of our Galaxy and M87 by imaging surrounding shadows, the study of plasma properties in the shadow formation regions, and the search for observational manifestations of wormholes; 3) the study of observational manifestations of the origin of life in the Universe - the search for water and biomarkers in the Galactic interstellar medium. Moreover, the technical capabilities of the MSO can help solve related problems, including the birth of the first galaxies and SMBHs (z βͺ 10), alternative approaches to measuring the Hubble constant, the physics of SMBHs in 'dusty' galactic nuclei, the study of protoplanetary disks and water transport in them, and the study of 'ocean worlds' in the Solar System. Β© 2021 Uspekhi Fizicheskikh Nauk, Russian Academy of Sciences and IOP Publishing.We appreciate the referees for their critical notes.Thestudy was partially supported by the project New Scientific Groups of LPI, no. 41-2020. AP thanks the RSF for its support (project 19-72-00064). AB is supported by RSF grant 18-12-00351 and by the State Target FEUZ-2020-0038. The work by IZ (Section 4) is supported by RFBR grant 18-02-00660. DV was supported by a grant from the Russian Government and Ministry of Higher Education and Science, 075-15-2020-780 (no. 13.1902.21.0039). The work by VSh (Section 4.4) was supported by a grant from the Russian Government for research by leading scientists under the program Studies of Stars with Exoplanets (agreement 075-15-2019-1875)
Drugs and drug-like molecules can modulate the function of mucosal-associated invariant T cells
The major-histocompatibility-complex-(MHC)-class-I-related molecule MR1 can present activating and non-activating vitamin-B-based ligands to mucosal-associated invariant T cells (MAIT cells). Whether MR1 binds other ligands is unknown. Here we identified a range of small organic molecules, drugs, drug metabolites and drug-like molecules, including salicylates and diclofenac, as MR1-binding ligands. Some of these ligands inhibited MAIT cells ex vivo and in vivo, while others, including diclofenac metabolites, were agonists. Crystal structures of a T cell antigen receptor (TCR) from a MAIT cell in complex with MR1 bound to the non-stimulatory and stimulatory compounds showed distinct ligand orientations and contacts within MR1, which highlighted the versatility of the MR1 binding pocket. The findings demonstrated that MR1 was able to capture chemically diverse structures, spanning mono- and bicyclic compounds, that either inhibited or activated MAIT cells. This indicated that drugs and drug-like molecules can modulate MAIT cell function in mammals
Diagnosis and Treatment of Irritable Bowel Syndrome: Clinical Recommendations of the Russian Gastroenterological Association and Association of Coloproctologists of Russia
Aim. Current clinical recommendations accentuate current methods for the diagnosis and treatment of irritable bowel syndrome (IBS).Key points. IBS is a functional bowel disorder manifested with recurrent, at least weekly, abdominal pain with the following attributes (any two leastwise): link to defecation, its frequency or stool shape. The symptoms are expected to persist for at minimum three months in a total six-month follow-up. Similar to other functional gastrointestinal (GI) disorders, IBS can be diagnosed basing on the patient symptoms compliance with Rome IV criteria, provided the absence of potentially symptom-causative organic GI diseases. Due to challenging differential diagnosis, IBS can be appropriately established per exclusionem, with pre-examination as follows: general and biochemical blood tests; tissue transglutaminase IgA/IgG antibody tests; thyroid hormones test; faecal occult blood test; hydrogen glucose/ lactulose breath test for bacterial overgrowth; stool test for enteric bacterial pathogens and Clostridium difficile A/B toxins; stool calprotectin test; abdominal ultrasound; OGDS, with biopsy as appropriate; colonoscopy with biopsy. The IBS sequence is typically wavelike, with alternating remissions and exacerbations often triggered by psychoemotional stress. Treatment of IBS patients includes dietary and lifestyle adjustments, various-class drug agents prescription and psychotherapeutic measures.Conclusion. Adherence to clinical recommendations can facilitate timely diagnosis and improve medical aid quality in patients with different clinical IBS variants
Guidelines of the Russian gastroenterological association and Russian Association of Coloproctology on diagnostics and treatment of ulcerative colitis in adults
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