Magnetic field enhanced radio frequency ion source and its application for Si-incorporation diamond-like carbon film preparation

Various ion sources are key components to prepare functional coatings,such as diamond-like carbon(DLC)films.In this article,we present our trying of surface modification on basis of Si-incorporation diamond-like carbon(Si-DLC)produced by a magnetic field enhanced radio frequency ion source,which is established to get high density plasma with the help of magnetic field.Under proper deposition process,a contact angle of 111°hydrophobic surface was achieved without any surface patterning,where nanostructure SiC grains appeared within the amorphous microstructure.The surface property was influenced by ion flow parameters as well as the resultant surface microstructure.The magnetic field enhanced radio frequency ion source developed in this paper was useful for protective film applications.

EXTREMELY LOW FREQUENCY MAGNETIC FIELD SUSCEPTIBILITY OF VISUAL DISPLAY UNITS

Extremely low frequency (ELF) magnetic field susceptibility is an index of visual display unit (VDU) quality and performance. This paper provided field measured data on the susceptibility for a large variety of VDUs. A test rig was built to study the susceptibility of VDUs to magnetic fields at fundamental and third harmonic frequencies. It was found that the susceptibility level is largely dependent on refresh rate of the VDU and the orientation of the external ELF field. It was also found that the VDU susceptibility is significantly increased in the presence of harmonic frequency magnetic fields. About 30% of the tested samples have susceptibility levels higher than that stated in IEC 1000-4-8 standard.

Combined Effects of 50 Hz Magnetic Field and Magnetic Nanoparticles on the Proliferation and Apoptosis of PC12 Cells

Objective To investigate the bioeffects of extremely low frequency （ELF） magnetic field （MF） （50 Hz, 400 μT） and magnetic nanoparticles （MNPs） via cytotoxicity and apoptosis assays on PC12 cells. Methods MNPs modified by SiO2 （MNP-SiO2） were characterized by transmission electron microscopy （TEM）, dynamic light scattering and hysteresis loop measurement. PC12 cells were administrated with MNP-SiO2 with or without MF exposure for 48 h. Cytotoxicity and apoptosis were evaluated with MTI- assay and annexin V-FITC/PI staining, respectively. The morphology and uptake of MNP-SiO2 were determined by TEM. MF simulation was performed by Ansoft Maxwell based on the finite element method. Results MNP-SiO2 were identified as -20 nm （diameter） ferromagnetic particles. MNP-SiO2 reduced cell viability in a dose-dependent manner. MF also reduced cell viability with increasing concentrations of MNP-SiO2. MNP-SiO2 alone did not cause apoptosis in PC12 cells; instead, the proportion of apoptotic cells increased significantly under MF exposure and increasing doses of MNP-SiO2. MNP-SiO2 could be ingested and then cause a slight change in cell morphology. Conclusion Combined exposure of MF and MNP-SiO2 resulted in remarkable cytotoxicity and increased apoptosis in PC12 cells. The results suggested that MF exposure could strengthen the MF of MNPs, which may enhance the bioeffects of ELF MF.

Numerical simulation of applied electromagnetic field and electromagnetic force in all-position welding

All-position welding is an important technology in energy sources, chemical, shipbuilding and other industries. When welding current is larger than 200 A, the molten metal tends to flow down due to the force of gravity. In order to ＂push＂ the molten metal into the weld, a new kind of U-frame excitation model, which could produce electromagnetic force to balance the gravity of the molten pool, was designed. The related parameters of the excitation model were simulated by Maxwell 3D, and the relationships between the parameters and the magnetic induction intensity were analyzed. Finally, the electromagnetic force in the molten pool was calculated, and the appropriate parameters of the U-frame excitation model were determined. The results of the simulation verify the feasibility of the all-position welding excitation model.

Meniscus Behavior in Electromagnetic Soft-Contact Continuous Casting Round Billet Mold

Using molten Pb-Sn-Bi alloy, the meniscus shape under high frequency magnetic field of φ100 mm round billet caster was investigated. The effect of some parameters on meniscus shape was studied. The results show that for a mold with 12 segments, the meniscus shape is relatively stable. With increasing power input, the menis- cus height increases with intensification of fluctuation. For the given caster, the reasonable power input is about 70 kW. The coil should be near to the top of mold and/or the initial meniscus should be near to the center of the coil. The lower the frequency, the higher is the meniscus height. With increasing frequency, the free surface is more flattened and meniscus becomes more stable. In practice, the power input should be increased simultaneously with frequency. The optimal frequency is about 20 kHz.

Electromagnetic Environmental Impact of 500-kV Double -Circuit Transmission Lines

The strength of the power frequency electric intensity and magnetic field of the 500-kV double circuit transmission lines was calculated by using the equivalent charge method and the Ampere's Law, and the environmental impact factors of the fields were evaluated. By optimizing the phase sequence, the frequency electric intensity and magnetic field strength can be reduced. Within a distance of 25 m from the center of the transmission line, the power frequency electric intensity and magnetic field strength fall off sharply with the distance increase. Finally, the best phase sequence and the minimum ground clearance of the transmission lines were obtained to meet the requirements of the least impact on envionment.

Effects of extremely low frequency magnetic field on anxiety level and spatial memory of adult rats

Background As the widespread use of electric devices in modern life, human are exposed to extremely low frequency magnetic fields （ELF MF） much more frequently than ever. Over the past decades, a substantial number of epidemiological and experimental studies have demonstrated that ELF MF （50 Hz） exposure is associated with increased risk of various health effects. The present study examined the effects of chronic exposure to ELF MF on anxiety level and spatial memory of adult rats. Methods The 50-Hz ELF MF was used during the whole experimental procedures and the value of magnetic field （MF） was set to 2 mT. Adult rats were divided randomly to control, MF 1 hour and MF 4 hours group. Anxiety-related behaviors were examined in the open field test and the elevated plus maze; changes in spatial learning and memory were determined in Morris water maze aRer 4 weeks of daily exposure. Results Rats in MF 4 hours group had increased anxiety-like behaviors with unaltered locomotor activity. In the Morris water maze test, rats had reduced latency to find the hidden platform and improved long-term memory of former location of platform without changes in short-term memory and locomotor activity. Conclusion Chronic ELF MF exposure has anxiogenic effect on rats, and the promoting effects on spatial learning and long-term retention of spatial memory.

Parametric Instability of a Liquid Metal Sessile Drop Under a High Frequency Amplitude-Modulate Magnetic Field

The parametric instability behavior of a liquid mercury sessile drop under high frequency Amplitude-Modulate Magnetic Field(AMMF),i.e.a high frequency magnetic field(carder wave)modulated by a low frequency sine wave(modulate wave),is investigated experimentally.The free surface contour of the mercury drop is observed by a CCD camera while varying the frequency and amplitude of the high frequency AMMF.At a given frequency and amplitude,the edge deformations with an azimuthal wave numbers(modes n=3,4,5,6)were excited.