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Equilibrium of a Solid Body Supported at One Point by a Rough Plane 由粗糙平面在一点上支承的固体的平衡
IF 0.8 4区 物理与天体物理
Doklady Physics Pub Date : 2022-03-13 DOI: 10.1134/S1028335821100049
G. M. Rozenblat
{"title":"Equilibrium of a Solid Body Supported at One Point by a Rough Plane","authors":"G. M. Rozenblat","doi":"10.1134/S1028335821100049","DOIUrl":"10.1134/S1028335821100049","url":null,"abstract":"<p>The problem of the possible and necessary (in the sense of Jellett) equilibrium of a solid body that is in contact at one of its points with a rough plane and is under the action of an arbitrary system of forces is considered. The mass distributions in the body (i.e., the central tensor of inertia and the position of the body center of mass relative to the supporting point) are assumed to be arbitrary. At the point of contact of the body with the support (unilateral constraint), a dry friction force acts obeying the classical Coulomb–Euler law. The necessary and sufficient conditions for obligatory equilibrium are obtained. These conditions are expressed by simple analytical formulas. A comparison is made with the corresponding results for the planar case obtained previously.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"66 10","pages":"296 - 302"},"PeriodicalIF":0.8,"publicationDate":"2022-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4545416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Lidar Monitoring of Moisture in Biological Objects 生物物体水分的激光雷达监测
IF 0.8 4区 物理与天体物理
Doklady Physics Pub Date : 2022-03-13 DOI: 10.1134/S1028335821100050
M. Ya. Grishin, V. N. Lednev, P. A. Sdvizhenskii, D. Yu. Pavkin, E. A. Nikitin, A. F. Bunkin, S. M. Pershin
{"title":"Lidar Monitoring of Moisture in Biological Objects","authors":"M. Ya. Grishin,&nbsp;V. N. Lednev,&nbsp;P. A. Sdvizhenskii,&nbsp;D. Yu. Pavkin,&nbsp;E. A. Nikitin,&nbsp;A. F. Bunkin,&nbsp;S. M. Pershin","doi":"10.1134/S1028335821100050","DOIUrl":"10.1134/S1028335821100050","url":null,"abstract":"<p>We performed for the first time experiments on laser remote sensing of the moisture content of biological objects essential for the agricultural industry. Probing was carried out using a fluorescence lidar based on a pulsed solid-state laser (527 nm, 5 ns, 1 kHz, 200 μJ/pulse), developed at the Prokhorov General Physics Institute, Russian Academy of Sciences, and a gated intensified charge coupled device camera. The spectra of laser fluorescence of various biological objects of plant origin were recorded at different humidity values. The loss of water was accompanied by the degradation of biological pigments, causing an uneven increase in the intensity of bands in the fluorescence spectrum for different spectral ranges. The ratio of the spectral bands of chlorophyll a (680 nm) and protochlorophyllide (630 nm) has the best correlation with residual moisture, which opens up a promising direction for lidar measurement and monitoring of moisture/dry matter in silage or perennial grasses.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"66 10","pages":"273 - 276"},"PeriodicalIF":0.8,"publicationDate":"2022-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4549722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Vibrational Dissipative Systems with Two Degrees of Freedom 二自由度的振动耗散系统
IF 0.8 4区 物理与天体物理
Doklady Physics Pub Date : 2022-03-13 DOI: 10.1134/S1028335821090056
A. G. Petrov
{"title":"Vibrational Dissipative Systems with Two Degrees of Freedom","authors":"A. G. Petrov","doi":"10.1134/S1028335821090056","DOIUrl":"10.1134/S1028335821090056","url":null,"abstract":"<p>Forced linear oscillations of dissipative mechanical systems with two degrees of freedom under the action of time-periodic forces are considered. The Lagrange equations are expressed in terms of three positive-definite quadratic forms: kinetic energy, dissipative function, and potential energy. The necessary and sufficient condition for simultaneous reducibility to diagonal forms of symmetric matrices of three real quadratic forms of two variables is formulated and proved. The condition was reduced to the equality of the third-order determinant of the coefficients of quadratic forms to zero. In this case, by linear transformation, the quadratic forms are reduced to the sum of squares and the equations are split into two independent second-order equations. The solution of the system is in a general analytical form. The effectiveness of the method is demonstrated by analyzing the forced oscillations of a double pendulum.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"66 9","pages":"264 - 268"},"PeriodicalIF":0.8,"publicationDate":"2022-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4545414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Omnidirectional Modulation of Seasonal Compression of the Earth’s Crust and the Aerosol Lidar Signal in a Tunnel above the Chamber of Elbrus Volcano 厄尔布鲁士火山室上方隧道中地壳季节压缩和气溶胶激光雷达信号的全向调制
IF 0.8 4区 物理与天体物理
Doklady Physics Pub Date : 2022-03-13 DOI: 10.1134/S1028335821110069
S. M. Pershin,  A. L. Sobisevich, M. Ya. Grishin, V. A. Zavozin, V. S. Makarov, V. N. Lednev, A. N. Fedorov, A. V. Myasnikov, D. G. Artemova
{"title":"Omnidirectional Modulation of Seasonal Compression of the Earth’s Crust and the Aerosol Lidar Signal in a Tunnel above the Chamber of Elbrus Volcano","authors":"S. M. Pershin,&nbsp; A. L. Sobisevich,&nbsp;M. Ya. Grishin,&nbsp;V. A. Zavozin,&nbsp;V. S. Makarov,&nbsp;V. N. Lednev,&nbsp;A. N. Fedorov,&nbsp;A. V. Myasnikov,&nbsp;D. G. Artemova","doi":"10.1134/S1028335821110069","DOIUrl":"10.1134/S1028335821110069","url":null,"abstract":"<p>From August to October 2019, the aerosol backscattering and deformation of the Earth’s crust were monitored in the tunnels of the Baksan Neutrino Observatory above the Elbrus volcano chamber. An omnidirectional modulation of the seasonal crust compression with a multiple excess of the average rate (~4 μm/day) and with a change in the sign of decrease in the lidar-signal scattering on aerosols to anomalous growth in the “hot” tunnel is found. It is established that the modulation is induced by the rapid cooling of the external atmosphere. The delays of the accelerated compression of the strainmeter arm (up to 14 μm/day) and the beginning of growth of the backscattering lidar signal relative to the beginning of the temperature decrease (~2 and ~7 days, respectively) are measured. The mechanism of the phenomena discovered is discussed.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"66 11","pages":"303 - 306"},"PeriodicalIF":0.8,"publicationDate":"2022-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4546805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Guaranteed Estimation of the State of a Dynamic System in the Presence of Observations with a Bounded Error Value 存在有界误差观测值时动态系统状态的保证估计
IF 0.8 4区 物理与天体物理
Doklady Physics Pub Date : 2022-03-13 DOI: 10.1134/S1028335821110070
A. M. Shmatkov
{"title":"Guaranteed Estimation of the State of a Dynamic System in the Presence of Observations with a Bounded Error Value","authors":"A. M. Shmatkov","doi":"10.1134/S1028335821110070","DOIUrl":"10.1134/S1028335821110070","url":null,"abstract":"<p>Equations are obtained for calculating the optimal guaranteed estimation of the state of a dynamic system from observational data in the presence of a bounded noise. For differential equations describing the desired estimation and linear in the phase vector and the vector of observations, within the framework of the ellipsoids method, it is shown that the optimal solution consists of sections where either the observational data or the properties of the system are ignored.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"66 11","pages":"329 - 332"},"PeriodicalIF":0.8,"publicationDate":"2022-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4548910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Prospects of Infrared Lasers in Air-Breathing Electric Thrusters 红外激光器在吸气式电动推力器中的应用前景
IF 0.8 4区 物理与天体物理
Doklady Physics Pub Date : 2022-03-13 DOI: 10.1134/S1028335821110045
S. L. Chernyshev, E. Yu. Loktionov, A. E. Sagalakov, V. V. Skvortsov, A. S. Filatyev, A. A. Uspensky
{"title":"Prospects of Infrared Lasers in Air-Breathing Electric Thrusters","authors":"S. L. Chernyshev,&nbsp;E. Yu. Loktionov,&nbsp;A. E. Sagalakov,&nbsp;V. V. Skvortsov,&nbsp;A. S. Filatyev,&nbsp;A. A. Uspensky","doi":"10.1134/S1028335821110045","DOIUrl":"10.1134/S1028335821110045","url":null,"abstract":"<p>The results of studies on the use of solid-state infrared lasers in combination with special targets for obtaining primary electrons in ionization chambers of plasma-ion thrusters are presented. Such thrusters being equipped with free molecular air intakes for using the surrounding atmosphere as a propellant for air-breathing electric thrusters, which are highly efficient for long-term maintenance of spacecraft in ultra-low orbits, providing significant advantages in Earth remote sensing and telecommunications. It is shown that the method of electron emission proposed can be an alternative to the current-heated cathodes used today, significantly increasing their lifetime.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"66 11","pages":"307 - 310"},"PeriodicalIF":0.8,"publicationDate":"2022-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4548912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Mathematical Modeling of an Interactive Transonic Boundary Layer with a Nonlinear Profile of Undisturbed Speed 具有非扰动速度非线性剖面的相互作用跨音速边界层的数学建模
IF 0.8 4区 物理与天体物理
Doklady Physics Pub Date : 2022-03-13 DOI: 10.1134/S1028335821110021
A. N. Bogdanov
{"title":"Mathematical Modeling of an Interactive Transonic Boundary Layer with a Nonlinear Profile of Undisturbed Speed","authors":"A. N. Bogdanov","doi":"10.1134/S1028335821110021","DOIUrl":"10.1134/S1028335821110021","url":null,"abstract":"<p>Using the triple-deck theory, a nonclassical boundary layer over a solid flat plate is investigated in the case of unsteady free viscous–inviscid interactions at transonic speeds. A feature of this study is the choice of the quadratic dependence of the longitudinal component of the unperturbed velocity in the boundary layer on the transverse coordinate and the variability of the pressure gradient. A qualitative difference between the flow pattern in the case considered and the case of a linear velocity profile in the boundary layer is shown.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"66 11","pages":"316 - 319"},"PeriodicalIF":0.8,"publicationDate":"2022-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4548894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The Effect of Secondary Boiling on the Dynamics of a Jet Formed during Vapor-Bubble Collapse Induced by Laser Heating of a Liquid 二次沸腾对激光加热液体汽泡坍缩过程中射流动力学的影响
IF 0.8 4区 物理与天体物理
Doklady Physics Pub Date : 2022-03-13 DOI: 10.1134/S1028335821110033
A. A. Chernov,  M. A. Guzev, A. A. Pil’nik, T. P. Adamova, A. A. Levin, V. M. Chudnovskii
{"title":"The Effect of Secondary Boiling on the Dynamics of a Jet Formed during Vapor-Bubble Collapse Induced by Laser Heating of a Liquid","authors":"A. A. Chernov,&nbsp; M. A. Guzev,&nbsp;A. A. Pil’nik,&nbsp;T. P. Adamova,&nbsp;A. A. Levin,&nbsp;V. M. Chudnovskii","doi":"10.1134/S1028335821110033","DOIUrl":"10.1134/S1028335821110033","url":null,"abstract":"<p>A single act of boiling a liquid underheated to the saturation temperature is experimentally investigated when the liquid is exposed to continu ous-wave laser radiation introduced into the working volume by means of a thin optical fiber. It is shown that a vapor bubble formed near the end of the optical fiber during collapse forms a hot cumulative jet, the phenomenon of secondary boiling around which is observed. The secondary vapor inclusion formed around the jet has an extended shape, moves, and evolves together with it. The significant effect of this inclusion on jet-propagation dynamics is demonstrated.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"66 11","pages":"325 - 328"},"PeriodicalIF":0.8,"publicationDate":"2022-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4548895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The Mechanism of Droplet Levitation in Gas–Droplet Flows Past Bodies 气态液滴流过物体时液滴悬浮的机理
IF 0.8 4区 物理与天体物理
Doklady Physics Pub Date : 2022-03-13 DOI: 10.1134/S1028335821120077
A. Yu. Varaksin, N. V. Vasil’ev, S. N. Vavilov
{"title":"The Mechanism of Droplet Levitation in Gas–Droplet Flows Past Bodies","authors":"A. Yu. Varaksin,&nbsp;N. V. Vasil’ev,&nbsp;S. N. Vavilov","doi":"10.1134/S1028335821120077","DOIUrl":"10.1134/S1028335821120077","url":null,"abstract":"<p>With the use of high-speed video filming, the effect of the appearance of droplets with near-zero velocities in gas–droplet flows past bodies was discovered for the first time. The formation of levitating droplets occurred as a result of the coalescence of droplets falling and reflected from the model. It has been suggested that the main mechanism for the appearance of drops with near-zero velocities is momentum exchange as a result of the collision of droplets with opposite directions and values of velocity close in magnitude. The effect of an increase in the size of large levitating drops due to the coalescence of falling droplets with them due to multiple collisions has been detected.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"66 12","pages":"345 - 347"},"PeriodicalIF":0.8,"publicationDate":"2022-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4548903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
The Radial Response of a Carbon Nanotube to Dynamic Pressure 碳纳米管对动压的径向响应
IF 0.8 4区 物理与天体物理
Doklady Physics Pub Date : 2022-03-13 DOI: 10.1134/S102833582112003X
S. V. Dmitriev,  M. A. Ilgamov
{"title":"The Radial Response of a Carbon Nanotube to Dynamic Pressure","authors":"S. V. Dmitriev,&nbsp; M. A. Ilgamov","doi":"10.1134/S102833582112003X","DOIUrl":"10.1134/S102833582112003X","url":null,"abstract":"<p>The radial dynamics of a single-walled carbon nanotube under dynamic compression is considered in a linear formulation. The equation based on the Kirchoff hypotheses for the bending deformation of a thin-walled cylindrical shell (circular ring) is applied. The effective parameter found by the comparison of eigenfrequencies within the framework of molecular dynamics and elastic shell theory is engaged. The applied external pressure is varied step by step and further remains constant within the time period considered. The vibratory motion and exponential deflection growth regimes are studied depending on the ratio of this pressure to the critical static pressure. These parameters can also be expressed through the number of carbon atoms composing a circular ring.</p>","PeriodicalId":533,"journal":{"name":"Doklady Physics","volume":"66 12","pages":"336 - 340"},"PeriodicalIF":0.8,"publicationDate":"2022-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4549727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
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