A strong electromagnetic field generated by a dipole

A strong electromagnetic field generated by a steep current pulse passing in a conductor dipole was measured. The current was created by an ultrashort voltage pulse formed in a coaxial transmitting line of a high-current picosecond electron accelerator.     

Particle characterization and separation by a coupled acoustic-gravity field

A coupled acoustic-gravity field is proposed as a novel external field for particle separation and characterization. When a standing plane ultrasound wave is generated, particles move to the node of the wave along the ultrasound force gradient. If the particles also undergo a sedimentation force, they aggregate at the equilibrium position, where these two forces are balanced. The equilibrium position, which is determined by the density and compressibility of a medium and particles, characterizes the particles. The local ultrasound energy, which is necessary for quantitative discussions, is evaluated by using a standard particle, the physical parameters of which are unambiguously determined; aluminum particles are used in the present study. The local ultrasound energy makes possible the determination of the compressibility of unknown materials. Nonporous particles of inorganic and polymeric materials, the particle sizes of which range from 3 to 100 microm, follow a derived model, suggesting that the local ultrasound energy and a derived model be valid. The proposed external field can be used for separation of particles having different acoustic natures.     

Paraelectric in a strong high-frequency field

A change in the effective permittivity of a ferroelectric film in the paraelectric phase under the action of a strong high-frequency field (nonequilibrium soft mode heating) is considered. It is shown that this effect must be most clearly pronounced far from the resonance (ω₀      

Collective dynamics of rotators coupled by a common pulsed field

The collective dynamics in an ensemble of active rotators coupled by a common pulsed field is studied. The dynamics of the ensemble is analyzed numerically for different values of system parameters. The calculated data, as functions of the synchronicity parameter, lead to a conclusion being drawn on the collective behavior of ensemble elements, the character of evolution of the ensemble field, and the dependence of the behavior of the ensemble field on the synchronicity of ensemble elements.     

Fabrication of textured alumina by electrophoretic deposition in a strong magnetic field

Textured alumina ceramics were fabricated by electrophoretic deposition in a strong magnetic field of 10 T (Tesla) followed by sintering. Single crystalline -alumina particles dispersed in aqueous media were aligned due to their anisotropic diamagnetic susceptibility and then deposited on a cathodic substrate. The degree of crystalline orientation of the as-deposited specimen characterized by X-ray diffraction was small but highly improved by sintering in the temperature range of 1273–1873 K. Microstructural observations showed the absence of any anisotropic grain growth.     

Bound electron states in a system of coupled quantum waveguides in a transverse electric field

It is shown that a bound electron state exists in a system of quantum waveguides laterally coupled via a small window and placed in a transverse electric field. A field-induced shift of the eigenvalue is estimated using a variational method.     

Phase field simulations of coupled microstructure solidification problems via the strong form particle difference method

This paper presents the development of a strong form-based collocation method called the particle difference method (PDM), capable of predicting the spatiotemporal evolution of polycrystalline material solidification through coupling of multi-phase and temperature fields. Cross coupled phase field evolution and heat transfer equations are discretized via the PDM to obtain the interface kinematics of polycrystalline boundary during solidification. A distinct feature of the PDM is its ability to represent derivative operators via a moving least-square approximation of the Taylor expansion through point-wise computations at collocation points. The method discretizes directly the strong forms using the pre-computed derivative operators at each collocation point and elegantly overcomes the topological difficulty in modeling intricate moving interfaces. To verify the efficacy of the PDM, numerical results are compared with those obtained from the conventional finite difference method for uniform and irregular distributions of the collocation points. The scalability of the parallelized PDM is tested by measuring its efficiency with increasing the number of processors. We also provide a solidification simulation with two ellipsoidal inclusions to demonstrate the capability of the PDM in complex moving interface problems with high curvature.     

Development of a magnetron sputtering system with an extraordinary strong magnetic field near the target

We have developed a planar sputtering device that uses a melt-processed bulk superconductor to generate the magnetic field. The magnetic field that confines the plasma above the sputtering target is about 1.0 T, which is about 20 times larger than the field normally used for magnetron sputtering. Because of the large magnetic field, discharge at an Ar gas pressure as low as 10⁻³ Pa was possible. In this study, we used the ultra-strong-field sputtering technique for depositing Ga-doped ZnO which is attracting interest as a transparent electrode material. We also studied the effect of employing an auxiliary coil to tailor the magnetic field distribution and discuss how the discharge characteristic had changed.     

弹性板/矩形腔耦合声场的响度分析

利用有限元结合间接边界元的方法分析弹性板/矩形腔耦合系统的内声场,通过与实验对比,验证了这种结构-声耦合法在预估板-空腔耦合系统声振特性的可行性。运用ISO532B响度计算标准的算法,分析封闭腔内不同位置测点处的特征响度变化规律,讨论参与耦合的弹性板厚度及边界条件对闭腔内声响度的影响。最后,以响度作为声品质的评价指标,通过参数化滤波的方法对闭腔内不同位置的测点的各特征频带进行处理,找出对人耳主观感觉影响较大的频率范围,从而为进行闭腔噪声控制和声品质改善提供参考。     

山地风场中特高压输电塔线体系动力可靠度研究

山地风场因受山体的干扰作用具有与平地风场截然不同的特征,对山地地形中结构高、跨度大和电压等级高的特高压输电塔线体系进行风振响应研究时,无法采用现有适用于平地风场的计算方法。为此,在风洞试验的基础上,首先对三类山地地形的不同工况,即单个山体的8种坡度,单个山体的3种高度以及两个山体的3种遮挡间距,对风场的影响分别进行了研究。通过对各工况下山体迎风面、山顶和背风面的平均风速加速比及湍流度的变化情况进行分析,提出了相应的修正公式,有效地考虑山地地形对风场的影响,得到了各工况下山地风场的平均特性和脉动特性。然后,基于试验数据及风场模型采用有限元计算理论对特高压输电塔线体系在各工况的风场条件下进行动力时程分析,并根据随机结构动力可靠度计算方法分别计算出各工况下特高压输电塔体的动力可靠度。最后,通过对比分析发现了不同山地地形条件下各工况中迎风面、山顶及背风面的不同位置输电塔体动力可靠度的变化规律。     

Realignment of slanted Fe nanorods on silicon substrates by a strong magnetic field

Slanted Fe nanorods prepared by glancing angle deposition on silicon substrates exhibited easy magnetization along their growth axis. By using a thin gold film on a silicon substrate as a buffer layer, slanted Fe nanorods can be realigned towards the substrate surface normal by a strong magnetic field. After realignment, the Fe nanorods retained the easy magnetization axis along their growth axis. The effects of the realignment by the strong magnetic field on the properties of the slanted Fe nanorods were also investigated. This study provides a possible way to fabricate magnetic nanostructures for perpendicular recording applications.     

Agitation of a liquid in a strong external electric field

This article considers the condition for instability of the surface waves in a liquid system in a strong external electric field. As a result of the viscosity, such surface waves lead to vigorous volume agitation, accelerating chemical and physicochemical processes occurring in the system.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 17, No. 6, pp. 981–988, December, 1969.     

Investigation of the parameters of laser radiation emitted by a single-frequency high-power gas laser

Studies to determine whether it is possible to obtain a stable single-frequency mode of generation in large He–Ne lasers were undertaken. Selection of the frequencies in the particular lasers was performed by means of a Fabry–Perot interferometer situated at a low angle to the axis of the cavity resonator. It is shown that a laser that has been converted to function in a single-frequency mode of emission assures a coherence length of at least 10 m even when subjected to technical vibratory and acoustic effects. Translated from Izmeritel’naya Tekhnika, No. 3, pp. 24–26, March, 2009.     

Temperature field of the active element of a solid-state laser with a liquid cooling system

Results of a numerical solution of a nonstationary conjugate convective heattransfer problem are presented. Temperature fields are determined in the coolant stream and in the body being cooled.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 39, No. 3, pp. 520–526, September, 1980.     

Two-dimensional gas of electrons in a strong magnetic field

Translated from Izmeritel'naya Tekhnika, No. 2, pp. 4–7, February, 1990.     

Jet emission from a capillary in a strong electric field

The phenomenon of multiple jet formation during a liquid efflux from a capillary in a strong electric field is considered. Conditions for the simultaneous emission of an arbitrary number of jets have been experimentally determined.     

Investigation of the electric field excited by a personal computer

The electromagnetic field produced by a personal computer at frequencies in the 20 Hz-30 MHz range is investigated experimentally. Data are obtained on the spectral composition and polarization of the electric component of the electromagnetic field. Measurements of the spatial structure and the field strength in the front half-space of the plane of the monitor are presented.Translated from Izmeritel'naya Tekhnika, No. 7, pp. 59–61, 1994.     

Investigation of a laser interferometric goniometer

The optico-mechanical circuit of an interference goniometer is presented. It is shown that the error of the goniometer in the range ±10° does not exceed 0.08″. Translated from Izmeritel'naya Tekhnika, No. 6, pp. 33–35, June, 1996.     

Low-temperature specific heat of a semiconductor in a strong magnetic field

We calculate the electronic specific heat of a semiconductor (GaAs) at very low temperatures when subjected to a magnetic field strong enough to make the electron distribution nondegenerate. The transition to nondegeneracy is characterized by a large and rapid increase in the specific heat. For large fields the value approaches that of a one-dimensional nondegenerate gas, after first exceeding this value. Zeeman splitting, even with a very smallg factor (0.32), almost doubles the maximum in the specific heat as a function of field.On leave from Centre de Recherches sur les Très Basses Températures, Grenoble, France.