Plasma confinement time in trimix-M galatea multipole magnetic trap

The confinement time of hydrogen plasma trapped in a Trimix-M magnetic multipole galatea was studied in a range of plasma densities (1 × 10¹⁶ − 6 × 10¹⁸ m⁻³) and ion energies (∼100–300 eV). It is established that (i) the confinement time increases with decreasing plasma density in the trap and (ii) as the barrier magnetic field is increased, the plasma confinement time grows faster than according to a linear law. The obtained results are indicative of a collisional character of plasma diffusion through the barrier field in the trap.     

Effect of pressure on plasma sheath in a magnetic field

The effects of collisions on plasma sheath in an external magnetic field have been investigated by considering the collisions between ions and neutral gas atoms. The ion fluid equations containing an external magnetic field and the collisions are solved numerically to study the ion dynamics under various pressures.     

Determination of plasma parameters with a probing magnetic field pulse

An experimental technique for the determination of electric conductivity and temperature of plasma is presented. The technique is based on comparing the signals that are produced by a pulsed magnetic field in the circuits of two probes located within the studied plasma and outside of it. The proposed technique for the measurement of plasma parameters was tested experimentally in the context of measuring the electric conductivity and temperature of plasma flux formed in cathode spots of a high-current pulsed vacuum arc with a magnesium cathode.     

Influence of additional magnetic field on plasma parameters in magnetron sputtering

With three additional magnetic rings being assembled outside the discharge room and connected with the magnetic field of the conventional unbalanced magnetron sputtering, a closed magnetic field configuration distribution had been formed in the whole discharge room and which can confine discharge plasma more effectively. The spatial distribution of the newly designed magnetic field configuration was simulated using the ANSYS software. Plasma potential, electron temperature, electron density and ion density in the discharge plasma were diagnosed by Langmuir probe and the optical emission line intensity ratios of Ar⁺/Ar and Cu⁺/Cu were studied by optical emission spectroscopy. The structure and morphology of the Cu films are measured by scanning electron microscopy. A comparative study of the new magnetic field configuration with the conventional unbalanced magnetic field configuration was conducted. The results showed that the application of the additional magnetic field can increase the plasma density, enhance the ionization degree of the sputtered Cu and decrease the plasma potential effectively. The characteristics of the deposited Cu film were also influenced by the new magnetic field configuration greatly.     

Effect of the starting temperature of a plasma jet on the change in its axial parameters

The effect of the starting temperature of a submerged argon plasma jet on its axial parameters is studied, and their dependences on dimensionless gas density from 11 to 81 are obtained.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 57, No. 1, pp. 54–56, July, 1989.     

等离子体化学气相沉积参量对Ar等离子体电子特性的影响

采用加热的调谐单探针技术。研究了射频辉光放电Ar等离子体空间电子能量分布函数,电子平均能量和电子密度,并系统分析了等离子体增强化学气相沉积工艺参量对等离子体空间电子特性的影响。     

Plasma trapping and confinement dynamics in a Trimix galatea

The Galatea-3 (MIREA) setup comprising a coaxial plasma gun, a plasma guide, and a Trimix galatea (containing three myxines) is briefly described. The plasma bunch parameters in the plasma guide and trap have been determined. It is demonstrated that plasma can be effectively trapped and spread in the proposed trap system. The confined plasma bunch protrudes out of the Ohkawa contour. Estimates show that the loss of particles from the trap is on a classical diffusion level.     

Study of the parameters of a two-phase jet and its effect on a barrier

Experimental and theoretical results are presented from a study of the parameters of a high-temperature two-phase jet and its thermal effect on a nonpermeable surface.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 52, No. 1, pp. 37–42, January, 1987.     

Effect of annealing parameters on the magnetic properties of NiZn ferrite thin films

Ni_0.5Zn_0.5Fe_2.0O_4.0 thin films (NZFs) were deposited on Si (100) substrate by a sol–gel method, and the effects of annealing parameters on the structure and magnetic properties of the proposed films were investigated. Moderate heating rate was beneficial to the nucleation of NZFs. When the heating rate was 2 °C/min the saturation magnetization (M _s) achieved its maximum and the coercivity (H _c) reached its minimum. Both the crystallization and M _s of NZFs enhanced with increasing annealing time; however, H _c changed contrarily. High quenching temperature produced a large stress and consequently deteriorated magnetic properties. The optimal annealing parameters of NZFs were annealed at 700 °C, heating rate 2 °C/min, annealing time 1 h, and gradually cooled to room temperature. Finally, NZFs showed a high magnetization of 320 emu/cm³ and low coercivity of 86 Oe.     

Effect of deposit conditions on magnetic parameters of electroless CoFeB films

Electroless CoFeB films with soft magnetic characteristics were fabricated on poly-ester plastic substrate using sodium tetrahydroborate (NaBH₄) as reducer. The change of film composition corresponding to magnetic characteristics was dependent on deposition conditions. As the concentration of NaBH₄ and bath pH increase, the surface roughness of films reduces approximately from 160 to 137 nm. The soft magnetic film exhibited large saturation magnetization of 145 emμ/cc and low coercivity of about 7.6 Oe. Low boron content in film was found resulting in higher coercivity. At 2 GHz, the real permeability and imaginary permeability of films are respectively 275 and 141 as the concentration of reducer is 0.066 mol/L. Hysteresis loops of films show a remanence close to the saturation magnetization and along the hard axis display anisotropic field of 75 Oe.     

Effect of dual swirling plasma arc cutting parameters on kerf characteristics

A numerical control 3-D processing system was constituted for dual swirling plasma arc cutting. The effect of cutting energy parameters and operating gases on kerf characteristics was then investigated experimentally, so as to provide a reference for appropriately selecting process parameters to improve cut quality. It is shown that kerf widths reduce, and the bevel angle and the straightness increase with an increase of cutting speed and a decrease of arc current. Moreover, a smaller bevel angle, together with greater straightness and more dross, exhibits on the low speed side of the cut. As the oxygen content of the operating gas decreases, kerf widths decrease and the dross increases, while the bevel angle varies slightly on the high speed side of the cut. For the pure oxygen and pure air processes, the bevel angle on the low speed side and the straightness of cut surface are the smallest, but the pure oxygen cut surface is the roughest due to the occurrence of a saw-like kerf.     

Influence of magnetizing parameters on the magnetic Barkhausennoise

Magnetic Barkhausen noise (MBN) measurements were made on a sample of pipeline steel as functions of magnetizing frequency and AC flux density in the sample. The observed MBN responses suggest a strong dependence on these magnetizing parameters. With increasing flux density in the sample, the MBN activity initially increases but finally begins to decrease at higher magnitudes of flux density. The MBN activity also increases with increasing magnetizing frequency. Pulse-height distribution analysis of the MBN waveforms suggests that the dependence of MBN activity on these magnetization parameters is more complex than appears from the rms voltage measurements     

Tunneling magnetoresistance modulation in a magnetic tunnel junction with a ferroelectric barrier

A simple model is developed to investigate the potential profile changes due to mechanical stress at the ferromagnetic/ferroelectric interfaces of ferromagnetic-ferroelectric-ferromagnetic tunnel junctions with an ultrathin ferroelectric barrier. The potential changes associated with the polarization variation have significant effects on the tunneling conductance of the junctions. The discovered effect is illustrated by the example of a multiferroic tunnel junction in which approximately four orders of changes of the tunneling conductance and several-fold changes of the tunneling magnetoresistance (TMR) are observed due to the spin-flip induced nanomechanical stress. The TMR modulation effect is essential for realization of novel spintronics nano-devices as well as being useful for investigating fundamental aspects of the spin transfer.     

表面纳米化与离子渗氮对304不锈钢的影响

为解决304不锈钢硬度低、耐磨性差的问题,本文采用预先表面纳米化,温度400、450℃,保温时间4、6 h,氮氢比1∶3的离子渗氮工艺对试样进行处理,研究纳米化以及渗氮工艺对304不锈钢渗氮层形貌和深度、硬度以及摩擦磨损性能的影响.利用金相显微镜、电子探针显微分析仪(EPMA)、能谱仪(EDS)、显微硬度计和磨损试验机对样品的显微组织、微观形貌、硬度及耐磨性进行了表征.结果表明:304不锈钢经表面纳米化与离子渗氮工艺处理后,渗氮层为0.1～0.2 mm,表面硬度约为1 200 HV0.1,比基体硬度提高了6～7倍,耐磨性也大大增强;但渗氮温度越高,保温时间越长,材料表面耐磨性越差.综合各种影响因素得出在本实验条件下最佳处理工艺为:预先表面纳米化,渗氮温度400℃、保温时间6 h.     

多弧离子镀沉积过程中等离子体参数对薄膜沉积的影响

采用平面探针测试了衬底附近的电流密度，弧电流和衬底偏压的增加均有助于增加到达衬底附近的离子的数量。弧电流增加引起村底的温升，衬底偏压对衬底温度影响较小。采用多弧离子镀技术沉积Cr-N薄膜，衬底偏压对薄膜的硬度影响较小；弧电流增大，薄膜的硬度随之降低。XRD分析表明，弧电流较高时，不利于Cr—N相的形成，薄膜中以Cr的宏观液滴为主，薄膜硬度较低。     

Optimizing the magnetic system parameters inside a measuring coil

Conclusions The magnetic core inside the coil of a magnetic measuring system has an optimal diameter to height ratio d_m/h_m for which the torque is maximal. The magnet diameter and height depend on the coil perimeter P, and their optimal ratio K_F is practically independent of the coil perimeter but depends on the alloy of which the magnet is made. Implementing optimal magnet dimensions makes possible fuller utilization of the energy of a permanent magnetic core inside the magnetic system coil. If the optimal ratio of magnet diameter to its height is known, calculation of the magnetic system parameters and the design of the entire measuring instrument becomes quite simple.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 32–34, April, 1991.     

溅射工艺及底层对SmCo薄膜磁性能的影响

用多靶射频磁控溅射系统在玻璃基片上制备了SmCo磁性薄膜。并采用控制变量法研究了溅射功率、溅射时间以及溅射气压等工艺参数对薄膜磁性能的影响。结果发现，当磁性层溅射功率为60W,溅射气压为0.5Pa，溅射时间为8min；底层溅射功率为125W，溅射气压为0．5Pa，溅射时间为4min时，薄膜的矫顽力高达2．79×10^5。底层对SmCo薄膜的磁性能也有影响，振动样品磁强计测量结果表明：相比Cr、Ti底层，以Cu作为底层所得到的SmCo薄膜磁性能更好，薄膜矫顽力分别比用Cr、Ti作底层时高出56％，40％。     

Hartree-fock-slater calculations on plasma parameters

A model is proposed for calculating plasma optical parameters; the calculated spectral absorption coefficients for various elements are compared with pubished values.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 58, No. 6, pp. 1012–1017, June, 1990.     

Dynamics of the magnetic field transport in a plasma opening switch

It is shown that the process of magnetic field penetration into the plasma bridge in a plasma opening switch is determined by the field diffusion near the magnetic piston, followed by the convective transport of magnetic field in the bridge. This transport is due to the field being “frozen in” to the flow of plasma behind the front of a shock wave, which is formed in the plasma accelerated by the magnetic field pressure.