9 research outputs found

    The effect of heat treatment on the microstructure and mechanical properties of 2d nanostructured au/nife system

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    Nanostructured NiFe film was obtained on silicon with a thin gold sublayer via pulsed electrodeposition and annealed at a temperature from 100 to 400β—¦C in order to study the effect of heat treatment on the surface microstructure and mechanical properties. High-resolution atomic force microscopy made it possible to trace stepwise evolving microstructure under the influence of heat treatment. It was found that NiFe film grains undergo coalescence twiceβ€”at ~100 and ~300Β°Cβ€”in the process of a gradual increase in grain size. The mechanical properties of the Au/NiFe nanostructured system have been investigated by nanoindentation at two various indentation depths, 10 and 50 nm. The results showed the opposite effect of heat treatment on the mechanical properties in the near-surface layer and in the material volume. Surface homogenization in combination with oxidation activation leads to abnormal strengthening and hardening-up of the near-surface layer. At the same time, a nonlinear decrease in hardness and Young’s modulus with increasing temperature of heat treatment characterizes the internal volume of nanostructured NiFe. An explanation of this phenomenon was found in the complex effect of changing the ratio of grain volume/grain boundaries and increasing the concentration of thermally activated diffuse gold atoms from the sublayer to the NiFe film. Β© 2020 by the authors. Licensee MDPI, Basel, Switzerland.Funding: The work was supported by Act 211 Government of the Russian Federation, contract β„– 02.A03.21.0011

    Efficiency of Magnetostatic Protection Using Nanostructured Permalloy Shielding Coatings Depending on Their Microstructure

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    The effect of microstructure on the efficiency of shielding or shunting of the magnetic fluxby permalloy shields was investigated in the present work. For this purpose, the FeNi shieldingcoatings with different grain structures were obtained using stationary and pulsed electrodeposition.The coatings’ composition, crystal structure, surface microstructure, magnetic domain structure, andshielding efficiency were studied. It has been shown that coatings with 0.2–0.6ΞΌm grains have adisordered domain structure. Consequently, a higher value of the shielding efficiency was achieved,but the working range was too limited. The reason for this is probably the hindered movement of thedomain boundaries. Samples with nanosized grains have an ordered two-domain magnetic structurewith a permissible partial transition to a superparamagnetic state in regions with a grain size of lessthan 100 nm. The ordered magnetic structure, the small size of the domain, and the coexistenceof ferromagnetic and superparamagnetic regions, although they reduce the maximum value ofthe shielding efficiency, significantly expand the working range in the nanostructured permalloyshielding coatings. As a result, a dependence between the grain and domain structure and theefficiency of magnetostatic shielding was found

    ΠžΠΏΡ‚ΠΈΠΌΠΈΠ·Π°Ρ†ΠΈΡ ΠΈΠ·Π»ΡƒΡ‡Π°ΡŽΡ‰Π΅ΠΉ ΠΊΠ°Ρ‚ΡƒΡˆΠΊΠΈ ΠΏΡ€ΠΎΠ³Ρ€Π°ΠΌΠΌΠ½ΠΎ-Π°ΠΏΠΏΠ°Ρ€Π°Ρ‚Π½ΠΎΠ³ΠΎ комплСкса для исслСдования эффСктивности экранирования низкочастотного элСктромагнитного излучСния

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    Optimization of the radiation coil of the hardware-software complex for studying the effectiveness of shielding of low-frequency electromagnetic radiation will make it possible to assess the effectiveness of shielding coatings at a higher level. This fact will make it possible to develop coatings with improved characteristics. The purpose of this work was to determine the optimal characteristics of the emitting coil which will ensure its stable operation and magnetic field strength in the frequency range up to 100 kHz.The parameters of the manufactured samples, such as inductance (L), active (R) and total resistance (Z), were obtained using an MNIPI E7-20 emittance meter. In practice, the coils with the optimal parameters calculated theoretically were connected to a current source and amplifier. To detect electromagnetic radiation, a multilayer inductor connected to a UTB-TREND 722-050-5 oscilloscope was used as a signal receiver.The results of measurements showed that the resistance of multilayer coils is approximately 1000 times higher than that of single-layer coils. Also, for multilayer coils, an avalanche-like increase in total resistance is observed starting from a frequency of 10 kHz, while for single-layer coils there is a uniform increase in total resistance over the entire frequency range up to 100 kHz.The paper presents results of research on the correlation of the performance of single-layer and multilayer inductors depending on their parameters in the frequency range from Β 20 Hz Β to Β 100 kHz. Values of the voltage required to provide the magnetic field strength of 1, 5, 20 Oe at 25 Hz and 100 kHz have been calculated. After analyzing the data obtained, the optimal parameters of the inductor were found which ensure stable performance in the frequency range up to 100 kHz.ΠžΠΏΡ‚ΠΈΠΌΠΈΠ·Π°Ρ†ΠΈΡ ΠΈΠ·Π»ΡƒΡ‡Π°ΡŽΡ‰Π΅ΠΉ ΠΊΠ°Ρ‚ΡƒΡˆΠΊΠΈ ΠΏΡ€ΠΎΠ³Ρ€Π°ΠΌΠΌΠ½ΠΎ-Π°ΠΏΠΏΠ°Ρ€Π°Ρ‚Π½ΠΎΠ³ΠΎ комплСкса для исслСдования эффСктивности экранирования низкочастотного элСктромагнитного излучСния ΠΏΠΎΠ·Π²ΠΎΠ»ΠΈΡ‚ Π½Π° Π±ΠΎΠ»Π΅Π΅ качСствСнном ΡƒΡ€ΠΎΠ²Π½Π΅ ΠΎΡ†Π΅Π½ΠΈΠ²Π°Ρ‚ΡŒ ΡΡ„Ρ„Π΅ΠΊΡ‚ΠΈΠ²Π½ΠΎΡΡ‚ΡŒ ΡΠΊΡ€Π°Π½ΠΈΡ€ΡƒΡŽΡ‰ΠΈΡ… ΠΏΠΎΠΊΡ€Ρ‹Ρ‚ΠΈΠΉ. Π”Π°Π½Π½Ρ‹ΠΉ Ρ„Π°ΠΊΡ‚ даст Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡ‚ΡŒ Ρ€Π°Π·Ρ€Π°Π±Π°Ρ‚Ρ‹Π²Π°Ρ‚ΡŒ покрытия с ΡƒΠ»ΡƒΡ‡ΡˆΠ΅Π½Π½Ρ‹ΠΌΠΈ характСристиками. ЦСлью Π΄Π°Π½Π½ΠΎΠΉ Ρ€Π°Π±ΠΎΡ‚Ρ‹ являлось ΠΎΠΏΡ€Π΅Π΄Π΅Π»Π΅Π½ΠΈΠ΅ ΠΎΠΏΡ‚ΠΈΠΌΠ°Π»ΡŒΠ½Ρ‹Ρ… характСристик ΠΈΠ·Π»ΡƒΡ‡Π°ΡŽΡ‰Π΅ΠΉ ΠΊΠ°Ρ‚ΡƒΡˆΠΊΠΈ, ΠΊΠΎΡ‚ΠΎΡ€Ρ‹Π΅ обСспСчат Π΅Ρ‘ ΡΡ‚Π°Π±ΠΈΠ»ΡŒΠ½ΡƒΡŽ Ρ€Π°Π±ΠΎΡ‚Ρƒ ΠΈ Π½Π°ΠΏΡ€ΡΠΆΡ‘Π½Π½ΠΎΡΡ‚ΡŒ ΠΌΠ°Π³Π½ΠΈΡ‚Π½ΠΎΠ³ΠΎ поля Π² частотном Π΄ΠΈΠ°ΠΏΠ°Π·ΠΎΠ½Π΅ Π΄ΠΎ 100 ΠΊΠ“Ρ†.ΠŸΠ°Ρ€Π°ΠΌΠ΅Ρ‚Ρ€Ρ‹ ΠΈΠ·Π³ΠΎΡ‚ΠΎΠ²Π»Π΅Π½Π½Ρ‹Ρ… ΠΎΠ±Ρ€Π°Π·Ρ†ΠΎΠ², Ρ‚Π°ΠΊΠΈΠ΅ ΠΊΠ°ΠΊ ΠΈΠ½Π΄ΡƒΠΊΡ‚ΠΈΠ²Π½ΠΎΡΡ‚ΡŒ, Π°ΠΊΡ‚ΠΈΠ²Π½ΠΎΠ΅ ΠΈ ΠΎΠ±Ρ‰Π΅Π΅ сопротивлСниС, Π±Ρ‹Π»ΠΈ ΠΏΠΎΠ»ΡƒΡ‡Π΅Π½Ρ‹, ΠΈΡΠΏΠΎΠ»ΡŒΠ·ΡƒΡ ΠΈΠ·ΠΌΠ΅Ρ€ΠΈΡ‚Π΅Π»ΡŒ иммитанса МНИПИ E7-20. На ΠΏΡ€Π°ΠΊΡ‚ΠΈΠΊΠ΅ ΠΊΠ°Ρ‚ΡƒΡˆΠΊΠΈ с ΠΎΠΏΡ‚ΠΈΠΌΠ°Π»ΡŒΠ½Ρ‹ΠΌΠΈ ΠΏΠ°Ρ€Π°ΠΌΠ΅Ρ‚Ρ€Π°ΠΌΠΈ, вычислСнными тСорСтичСски, Π±Ρ‹Π»ΠΈ ΠΏΠΎΠ΄ΠΊΠ»ΡŽΡ‡Π΅Π½Ρ‹ ΠΊ источнику ΠΈ ΡƒΡΠΈΠ»ΠΈΡ‚Π΅Π»ΡŽ Ρ‚ΠΎΠΊΠ°. Для дСтСктирования элСктромагнитного излучСния Π² качСствС ΠΏΡ€ΠΈΡ‘ΠΌΠ½ΠΈΠΊΠ° сигнала использовалась многослойная ΠΊΠ°Ρ‚ΡƒΡˆΠΊΠ° индуктивности, ΠΏΠΎΠ΄ΠΊΠ»ΡŽΡ‡Ρ‘Π½Π½Π°Ρ ΠΊ осциллографу UTB-TREND 722-050-5.Π Π΅Π·ΡƒΠ»ΡŒΡ‚Π°Ρ‚Ρ‹ ΠΈΠ·ΠΌΠ΅Ρ€Π΅Π½ΠΈΠΉ ΠΏΠΎΠΊΠ°Π·Π°Π»ΠΈ, Ρ‡Ρ‚ΠΎ сопротивлСниС многослойных ΠΊΠ°Ρ‚ΡƒΡˆΠ΅ΠΊ ΠΏΡ€ΠΈΠ±Π»ΠΈΠ·ΠΈΡ‚Π΅Π»ΡŒΠ½ΠΎ Π² 1000 Ρ€Π°Π· большС сопротивлСния однослойных. Π’Π°ΠΊΠΆΠ΅ Ρƒ многослойных ΠΊΠ°Ρ‚ΡƒΡˆΠ΅ΠΊ Π½Π°Π±Π»ΡŽΠ΄Π°Π΅Ρ‚ΡΡ Π»Π°Π²ΠΈΠ½ΠΎΠΎΠ±Ρ€Π°Π·Π½Ρ‹ΠΉ рост ΠΎΠ±Ρ‰Π΅Π³ΠΎ сопротивлСния, начиная с частоты 10 ΠΊΠ“Ρ†, Π² Ρ‚ΠΎ врСмя ΠΊΠ°ΠΊ Ρƒ однослойных ΠΊΠ°Ρ‚ΡƒΡˆΠ΅ΠΊ происходит Ρ€Π°Π²Π½ΠΎΠΌΠ΅Ρ€Π½Ρ‹ΠΉ рост ΠΎΠ±Ρ‰Π΅Π³ΠΎ сопротивлСния Π½Π° всём Π΄ΠΈΠ°ΠΏΠ°Π·ΠΎΠ½Π΅ частот Π΄ΠΎ 100 ΠΊΠ“Ρ†. ΠŸΡ€Π΅Π΄ΡΡ‚Π°Π²Π»Π΅Π½Ρ‹ Ρ€Π΅Π·ΡƒΠ»ΡŒΡ‚Π°Ρ‚Ρ‹ исслСдований коррСляции Ρ€Π°Π±ΠΎΡ‡ΠΈΡ… характСристик  однослойных Β ΠΈ многослойных  ΠΊΠ°Ρ‚ΡƒΡˆΠ΅ΠΊΒ  индуктивности  Π²Β  зависимости  ΠΎΡ‚Β  ΠΈΡ…Β  ΠΏΠ°Ρ€Π°ΠΌΠ΅Ρ‚Ρ€ΠΎΠ²Β  Π²Β  частотном  Π΄ΠΈΠ°ΠΏΠ°Π·ΠΎΠ½Π΅ ΠΎΡ‚ 20 Π“Ρ† Π΄ΠΎ 100 ΠΊΠ“Ρ†. Рассчитаны значСния напряТСния, Π½Π΅ΠΎΠ±Ρ…ΠΎΠ΄ΠΈΠΌΠΎΠ³ΠΎ для обСспСчСния напряТённости ΠΌΠ°Π³Π½ΠΈΡ‚Π½ΠΎΠ³ΠΎ поля 1, 5, 20 Π­ ΠΏΡ€ΠΈ 25 Π“Ρ† ΠΈ 100 ΠΊΠ“Ρ†. ΠŸΡ€ΠΎΠ°Π½Π°Π»ΠΈΠ·ΠΈΡ€ΠΎΠ²Π°Π² ΠΏΠΎΠ»ΡƒΡ‡Π΅Π½Π½Ρ‹Π΅ Π΄Π°Π½Π½Ρ‹Π΅, Π½Π°ΠΉΠ΄Π΅Π½Ρ‹ ΠΎΠΏΡ‚ΠΈΠΌΠ°Π»ΡŒΠ½Ρ‹Π΅ ΠΏΠ°Ρ€Π°ΠΌΠ΅Ρ‚Ρ€Ρ‹ ΠΊΠ°Ρ‚ΡƒΡˆΠΊΠΈ индуктивности, ΠΎΠ±Π΅ΡΠΏΠ΅Ρ‡ΠΈΠ²Π°ΡŽΡ‰ΠΈΠ΅ ΡΡ‚Π°Π±ΠΈΠ»ΡŒΠ½Ρ‹Π΅ Ρ€Π°Π±ΠΎΡ‡ΠΈΠ΅ характСристики Π² Π΄ΠΈΠ°ΠΏΠ°Π·ΠΎΠ½Π΅ частот Π΄ΠΎ 100 ΠΊΠ“Ρ†

    Mechanisms of elastoplastic deformation and their effect on hardness of nanogranular Ni-Fe coatings

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    This article contains the study of correlation between the microstructure, mechanical properties and mechanisms of elastoplastic deformation of Ni-Fe coatings that were grown in five electrodeposition modes and had fundamentally different microstructures. A nonlinear change in hardness was detected using nanoindentation. Explanation of the abnormal change in hardness was found in the nature of the relaxation method of elastoplastic energy under load. It is shown that the deformation of coatings with a grain size of 100 nm or more occurs due to dislocation slip. A decrease in grain size leads to the predominance of deformation due to rotations and sliding of grains, as well as surface and grain boundary diffusion. The effect of deformation mechanisms on the nanoscale hardness of Ni-Fe coatings was established. Full hardening of the coatings (both in the bulk and on the surface) was achieved while maintaining the balance of three mechanisms of elastoplastic deformation in the sample. Unique coatings consisting of two fractions of grains (70% of nano-grains and 30% of their agglomerates) demonstrate high crack resistance and full-depth hardening up to H = 7.4 GPa due to the release of deformation energy for amorphization and agglomeration of nanograins. Β© 2021King Abdullah University of Science and Technology, KAUSTGovernment Council on Grants, Russian FederationFunding text 1: The work was supported by Act 211 Government of the Russian Federation, contract β„– 02.A03.21.0011. Dmitry Lyakhov and Dominik Michels are partially supported by KAUST (baseline funding).Funding text 2: The work was supported by Act 211 Government of the Russian Federation, contract ? 02.A03.21.0011. Dmitry Lyakhov and Dominik Michels are partially supported by KAUST (baseline funding)

    Combined Effect of Microstructure, Surface Energy, and Adhesion Force on the Friction of PVA/Ferrite Spinel Nanocomposites

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    Nanocomposite films based on spinel ferrite (Mg0.8Zn0.2Fe1.5Al0.5O4) in a PVA matrix were obtained. An increase in the spinel concentration to 10 wt.% caused an avalanche-like rise in roughness due to the formation of nanoparticle agglomerates. The lateral mode of atomic force microscopy (AFM) allowed us to trace the agglomeration dynamics. An unexpected result was that the composite with 6 wt.% of filler had a low friction coefficient in comparison with similar composites due to the successfully combined effects of low roughness and surface energy. The friction coefficient decreased to 0.07 when the friction coefficient of pure PVA was 0.72. A specially developed method for measuring nano-objects’ surface energy using AFM made it possible to explain the anomalous nature of the change in tribological characteristics. Β© 2022 by the authors. Licensee MDPI, Basel, Switzerland.National University of Science and Technology,Β MISISAlex V. Trukhanov thanks NUST MISIS for support within the framework of the Β«Priority 2030Β»

    ВлияниС Π³Π°Π±Π°Ρ€ΠΈΡ‚Π½Ρ‹Ρ… ΠΏΠ°Ρ€Π°ΠΌΠ΅Ρ‚Ρ€ΠΎΠ² цилиндричСского экрана Π½Π° ΡΡ„Ρ„Π΅ΠΊΡ‚ΠΈΠ²Π½ΠΎΡΡ‚ΡŒ экранирования

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    Study of dimensional parametersΚΌ influence on shielding properties of cylindrical shields will allow to optimise the fusion process, as well as to reduce production costs by reducing the material used. The purpose of this work was to compare results of theoretical calculation of shielding effectiveness of an infinite cylindrical shield with the data obtained in real conditions.A cylindrical Ni-Fe shield was synthesised by electrochemical deposition with length of 32 cm, diameter of 4.5 cm and shielding thickness of β‰ˆ 100 Β΅m. The cylinder length was then reduced from 32 cm to 6 cm in 4 cm increments and for each cylinder length shielding effectiveness was measured using three-coordinate Helmholtz field-forming system.The measurement results show that the calculation of shielding effectiveness of infinite cylindrical shield is valid for cylinder lengths l β‰₯ 18–20 cm. Shielding effectiveness is markedly reduced at values of l Λ‚ 15 cm.Analysis of data obtained allowed to conclude that it is necessary to determine the correction factor when calculating a cylindrical screen shielding efficiencyΠ˜Π·ΡƒΡ‡Π΅Π½ΠΈΠ΅ влияния Π³Π°Π±Π°Ρ€ΠΈΡ‚Π½Ρ‹Ρ… ΠΏΠ°Ρ€Π°ΠΌΠ΅Ρ‚Ρ€ΠΎΠ² Π½Π° ΡΠΊΡ€Π°Π½ΠΈΡ€ΡƒΡŽΡ‰ΠΈΠ΅ свойства цилиндричСских экранов ΠΏΠΎΠ·Π²ΠΎΠ»ΠΈΡ‚ ΠΎΠΏΡ‚ΠΈΠΌΠΈΠ·ΠΈΡ€ΠΎΠ²Π°Ρ‚ΡŒ процСсс синтСза, Π° Ρ‚Π°ΠΊΠΆΠ΅ ΡΠ½ΠΈΠ·ΠΈΡ‚ΡŒ Π·Π°Ρ‚Ρ€Π°Ρ‚Ρ‹ Π½Π° производство, Π·Π° счёт ΡƒΠΌΠ΅Π½ΡŒΡˆΠ΅Π½ΠΈΡ ΠΈΡΠΏΠΎΠ»ΡŒΠ·ΡƒΠ΅ΠΌΠΎΠ³ΠΎ ΠΌΠ°Ρ‚Π΅Ρ€ΠΈΠ°Π»Π°. ЦСлью Π΄Π°Π½Π½ΠΎΠΉ Ρ€Π°Π±ΠΎΡ‚Ρ‹ Π±Ρ‹Π»ΠΎ сравнСниС Ρ€Π΅Π·ΡƒΠ»ΡŒΡ‚Π°Ρ‚ΠΎΠ² тСорСтичСского расчёта эффСктивности экранирования бСсконСчного цилиндричСского экрана ΠΈ Π΄Π°Π½Π½Ρ‹Ρ…, ΠΏΠΎΠ»ΡƒΡ‡Π΅Π½Π½Ρ‹Ρ… Π² Ρ€Π΅Π°Π»ΡŒΠ½Ρ‹Ρ… условиях.ΠœΠ΅Ρ‚ΠΎΠ΄ΠΎΠΌ элСктрохимичСского осаТдСния Π±Ρ‹Π» синтСзирован цилиндричСский экран Ni-Fe, Π΄Π»ΠΈΠ½Π° ΠΊΠΎΡ‚ΠΎΡ€ΠΎΠ³ΠΎ составила 32 см, Π΄ΠΈΠ°ΠΌΠ΅Ρ‚Ρ€ 4,5 см, Ρ‚ΠΎΠ»Ρ‰ΠΈΠ½Π° ΡΠΊΡ€Π°Π½ΠΈΡ€ΡƒΡŽΡ‰Π΅Π³ΠΎ покрытия ΡΠΎΡΡ‚Π°Π²ΠΈΠ»Π°β‰ˆ 100 ΠΌΠΊΠΌ. Π—Π°Ρ‚Π΅ΠΌ Π΄Π»ΠΈΠ½Π° Ρ†ΠΈΠ»ΠΈΠ½Π΄Ρ€Π° ΡƒΠΌΠ΅Π½ΡŒΡˆΠ°Π»Π°ΡΡŒ ΠΎΡ‚ 30 Π΄ΠΎ 6 см с шагом Π² 4 см, для ΠΊΠ°ΠΆΠ΄ΠΎΠΉ Π΄Π»ΠΈΠ½Ρ‹ Ρ†ΠΈΠ»ΠΈΠ½Π΄Ρ€Π° Π±Ρ‹Π»Π° ΠΈΠ·ΠΌΠ΅Ρ€Π΅Π½Π° ΡΡ„Ρ„Π΅ΠΊΡ‚ΠΈΠ²Π½ΠΎΡΡ‚ΡŒ экранирования с ΠΏΠΎΠΌΠΎΡ‰ΡŒΡŽ ΠΏΠΎΠ»Π΅ΠΎΠ±Ρ€Π°Π·ΡƒΡŽΡ‰Π΅ΠΉ систСмы Ρ‚Ρ€Ρ‘Ρ…ΠΊΠΎΠΎΡ€Π΄ΠΈΠ½Π°Ρ‚Π½Ρ‹Ρ… ΠΊΠ°Ρ‚ΡƒΡˆΠ΅ΠΊ Π“Π΅Π»ΡŒΠΌΠ³ΠΎΠ»ΡŒΡ†Π°.Π Π΅Π·ΡƒΠ»ΡŒΡ‚Π°Ρ‚Ρ‹ ΠΈΠ·ΠΌΠ΅Ρ€Π΅Π½ΠΈΠΉ ΠΏΠΎΠΊΠ°Π·Π°Π»ΠΈ, Ρ‡Ρ‚ΠΎ расчёт эффСктивности экранирования бСсконСчного цилиндричСского экрана справСдлив ΠΏΡ€ΠΈ Π΄Π»ΠΈΠ½Π΅ Ρ†ΠΈΠ»ΠΈΠ½Π΄Ρ€Π° l β‰₯ 18–20 см. ΠŸΡ€ΠΈ значСниях l Λ‚ 15 см ΡΡ„Ρ„Π΅ΠΊΡ‚ΠΈΠ²Π½ΠΎΡΡ‚ΡŒ экранирования Π·Π°ΠΌΠ΅Ρ‚Π½ΠΎ сниТаСтся.Анализ ΠΏΠΎΠ»ΡƒΡ‡Π΅Π½Π½Ρ‹Ρ… Π΄Π°Π½Π½Ρ‹Ρ… ΠΏΠΎΠ·Π²ΠΎΠ»ΠΈΠ» ΡΠ΄Π΅Π»Π°Ρ‚ΡŒ Π²Ρ‹Π²ΠΎΠ΄ ΠΎ нСобходимости опрСдСлСния ΠΏΠΎΠΏΡ€Π°Π²ΠΎΡ‡Π½ΠΎΠ³ΠΎ коэффициСнта ΠΏΡ€ΠΈ расчётах эффСктивности экранирования цилиндричСского экрана

    ΠžΠΏΡ‚ΠΈΠΌΠΈΠ·Π°Ρ†ΠΈΡ ΠΈΠ·Π»ΡƒΡ‡Π°ΡŽΡ‰Π΅ΠΉ ΠΊΠ°Ρ‚ΡƒΡˆΠΊΠΈ ΠΏΡ€ΠΎΠ³Ρ€Π°ΠΌΠΌΠ½ΠΎ- Π°ΠΏΠΏΠ°Ρ€Π°Ρ‚Π½ΠΎΠ³ΠΎ комплСкса для исслСдования эффСктивности экранирования низкочастотного элСктромагнитного излучСния

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    Optimization of the radiation coil of the hardware-software complex for studying the effectiveness of shielding of low-frequency electromagnetic radiation will make it possible to assess the effectiveness of shielding coatings at a higher level. This fact will make it possible to develop coatings with improved characteristics. The purpose of this work was to determine the optimal characteristics of the emitting coil which will ensure its stable operation and magnetic field strength in the frequency range up to 100 kHz. The parameters of the manufactured samples, such as inductance (L), active (R) and total resistance (Z), were obtained using an MNIPI E7-20 emittance meter. In practice, the coils with the optimal parameters calculated theoretically were connected to a current source and amplifier. To detect electromagnetic radiation, a multilayer inductor connected to a UTB-TREND 722-050-5 oscilloscope was used as a signal receiver. The results of measurements showed that the resistance of multilayer coils is approximately 1000 times higher than that of single-layer coils. Also, for multilayer coils, an avalanche-like increase in total resistance is observed starting from a frequency of 10 kHz, while for single-layer coils there is a uniform increase in total resistance over the entire frequency range up to 100 kHz. The paper presents results of research on the correlation of the performance of single-layer and multilayer inductors depending on their parameters in the frequency range from 20 Hz to 100 kHz. Values of the voltage required to provide the magnetic field strength of 1, 5, 20 Oe at 25 Hz and 100 kHz have been calculated. After analyzing the data obtained, the optimal parameters of the inductor were found which ensure stable performance in the frequency range up to 100 kHz

    Influence of Cylindrical Shield Dimensions on Shielding Effectiveness

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    Study of dimensional parametersΚΌ influence on shielding properties of cylindrical shields will allow to optimise the fusion process, as well as to reduce production costs by reducing the material used. The purpose of this work was to compare results of theoretical calculation of shielding effectiveness of an infinite cylindrical shield with the data obtained in real conditions. A cylindrical Ni-Fe shield was synthesised by electrochemical deposition with length of 32 cm, diameter of 4.5 cm and shielding thickness of β‰ˆ 100 ΞΌm. The cylinder length was then reduced from 32 cm to 6 cm in 4 cm increments and for each cylinder length shielding effectiveness was measured using three-coordinate Helmholtz field-forming system. The measurement results show that the calculation of shielding effectiveness of infinite cylindrical shield is valid for cylinder lengths l β‰₯ 18–20 cm. Shielding effectiveness is markedly reduced at values of l Λ‚ 15 cm. Analysis of data obtained allowed to conclude that it is necessary to determine the correction factor when calculating a cylindrical screen shielding efficiency
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