Власнi частоти та власнi форми регулярних ланцюгових коливальних систем

The classical approach in the investigation of natural oscillations of discrete mechanical oscillatingsystems is the solution of the secular equation for finding the eigenfrequencies and the system of algebraic equations for determining the amplitude coefficients (eigenforms). However, the analytical solution of the secular equation is possible only for a limited class of discrete systems, especially with a finite degree of freedom. This class includes regular chain oscillating systems in which the same oscillators are connected in series. Regular systems are divided into systems with rigidly fixed ends, with one or both free ends, which significantly affects the search for eigenfrequencies and eigenforms. This paper shows how, having a solution for the secular equation of a regular system with rigidly fixed ends, it is possible to determine the eigenfrequencies and eigenforms of regular systems with one or both free ends. Pages of the article in the issue: 88 - 93 Language of the article: UkrainianКласичним пiдходом при дослiдженнi власних коливань дискретних коливальних механiчних систем є розв’язання вiкового рiвняння для знаходження власних частот та системи алгебраїчних рiвнянь для визначення амплiтудних коефiцiєнтiв. Однак, аналiтичне розв’язання вiкового рiвняння можливе тiльки для обмеженого кола дискретних систем, особливо зi скiнченним ступенем вiльностi. До такого класу вiдносяться регулярнi ланцюговi коливальнi системи, в яких однаковi осцилятори з’єднанi мiж собою послiдовно. Регулярнi системи роздiляються на системи з жорстко закрiпленими кiнцями, з одним або обома вiльними кiнцями, що суттєво впливає на пошук власних частот та власних форм. В данiй статтi показано, як маючи розв’язок для вiкового рiвняння регулярної системи з жорстко закрiпленими кiнцями, можна визначити власнi частоти та власнi форми регулярних систем з одним чи обома вiльними кiнцями

The disappearance of the dependence of actin-myosin interaction on the phosphorylation of myosin light chains in the "freezing" of the structure of heavy meromyosin by a bifunctional reagent

Using glycerinated muscle fibers, free of myosin, tropomyosin and troponin, a study was made of the structural state of F-actin modified by N-(iodoacetyl)-N'-(1-naphthyl-5-sulfo)-ethylendiamine (1.5-IAEDANS) and by rhodaminyl--phalloin at decoration of thin filaments with a proteolytic fragment of myosin--heavy meromyosin containing phosphorylated and dephosphorylated myosin light chains. The heavy meromyosin used has three SH-groups of heavy chain SH1, SH2 and SH chi modified by bifunctional reagent N,N'-n-phenylmaleimide (SH1-SH2, SH2-SH chi). At decoration of thin filaments with heavy meromyosin, some changes in polarized fluorescence of rhodaminyl--phalloin and 1.5-IAEDANS independent of phosphorylation of myosin light chains were found. Fluorescence anisotropy of the fiber was found to depend primarily on the character of heavy chain of SH-group modification. The ability of heavy chains to change their conformations is supposed to play an important role in the mechanism of myosin system modulation of muscle contraction