scholarly journals Investigation of the Thermal Properties of Electrodes on the Film and Its Heating Behavior Induced by Microwave Irradiation in Mounting Processes

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 557
Author(s):  
Kenji Kanazawa ◽  
Takashi Nakamura ◽  
Masateru Nishioka ◽  
Sei Uemura
Keyword(s):  
Magnetic Field ◽  
Electric Fields ◽  
Single Mode ◽  
Heating System ◽  
Solder Paste ◽  
The Novel ◽  
Electronic Components ◽  
Short Time ◽  
Heating Behavior ◽  
The Magnetic Field

We have developed a novel microwave (MW) soldering system using a cylindrical single-mode TM110 MW cavity that spatially separates the electric fields at the top and bottom of the cavity and the magnetic field at the center of the cavity. This MW reactor system automatically detects the suitable resonance frequency and provides the optimum MW irradiation conditions in the cylindrical cavity via a power feedback loop. Furthermore, we investigated the temperature properties of electrodes by MW heating with the simulation of a magnetic field in the TM110 cavity toward the mounting of electronic components by MW heating. We also developed a short-time melting technology for solder paste on polyimide substrate using MW heating and succeeded in mounting a temperature sensor using the novel MW heating system without damaging the electronic components, electronic circuits, and the substrate.

scholarly journals Mapping of steady-state electric fields and convective drifts in geomagnetic fields – Part 1: Elementary models

2016 ◽  
Vol 34 (1) ◽  
pp. 55-65 ◽  
Author(s):  
A. D. M. Walker ◽  
G. J. Sofko
Keyword(s):  
Magnetic Field ◽  
Steady State ◽  
Electric Field ◽  
Electric Fields ◽  
Magnetic Field Line ◽  
Geomagnetic Field ◽  
Geomagnetic Field Models ◽  
Spatial Derivatives ◽  
Field Lines ◽  
The Magnetic Field

Abstract. When studying magnetospheric convection, it is often necessary to map the steady-state electric field, measured at some point on a magnetic field line, to a magnetically conjugate point in the other hemisphere, or the equatorial plane, or at the position of a satellite. Such mapping is relatively easy in a dipole field although the appropriate formulae are not easily accessible. They are derived and reviewed here with some examples. It is not possible to derive such formulae in more realistic geomagnetic field models. A new method is described in this paper for accurate mapping of electric fields along field lines, which can be used for any field model in which the magnetic field and its spatial derivatives can be computed. From the spatial derivatives of the magnetic field three first order differential equations are derived for the components of the normalized element of separation of two closely spaced field lines. These can be integrated along with the magnetic field tracing equations and Faraday's law used to obtain the electric field as a function of distance measured along the magnetic field line. The method is tested in a simple model consisting of a dipole field plus a magnetotail model. The method is shown to be accurate, convenient, and suitable for use with more realistic geomagnetic field models.

INFLUENCE OF THE MAGNETIC FIELD ON THE TRANSVERSE RUNAWAY THRESHOLD

2007 ◽  
Vol 21 (10) ◽  
pp. 1715-1720 ◽  
Author(s):  
NANA METREVELI ◽  
ZAUR KACHLISHVILI ◽  
BEKA BOCHORISHVILI
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Electric Fields ◽  
Applied Electric Field ◽  
Nonlinear Oscillations ◽  
Hot Electrons ◽  
Total Field ◽  
Practical Applications ◽  
Energy And Momentum ◽  
The Magnetic Field

The transverse runaway (TR) is a phenomenon whereby for a certain combination of energy and momentum scattering mechanisms of hot electrons, and for a certain threshold of the applied electric field, the internal (total) field tends to infinity. In this work, the effect of the magnetic field on the transverse runaway threshold is considered. It is shown that with increasing magnetic field, the applied critical electric fields relevant to TR decrease. The obtained results are important for practical applications of the TR effect as well as for the investigation of possible nonlinear oscillations that may occur near the TR threshold.

ELECTROMAGNETIC FIELDS IN AN N‐LAYER ANISOTROPIC HALF‐SPACE

Geophysics ◽  
1967 ◽  
Vol 32 (4) ◽  
pp. 668-677 ◽  
Author(s):  
Douglas P. O’Brien ◽  
H. F. Morrison
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Plane Wave ◽  
Half Space ◽  
Electric Fields ◽  
Field Measurements ◽  
Large Scatter ◽  
Tensor Impedance ◽  
The Magnetic Field ◽  
Made In

From Maxwell’s equations and Ohm’s law for a horizontally anisotropic medium, it may be shown that two independent plane wave modes propagate perpendicular to the plane of the anisotropy. Boundary conditions at the interfaces in an n‐layered model permit the calculation, through successive matrix multiplications, of the fields at the surface in terms of the fields propagated into the basal infinite half space. Specifying the magnetic field at the surface allows the calculation of the resultant electric fields, and the calculation of the entries of a tensor impedance relationship. These calculations have been programmed for the digital computer and an interpretation of impedances obtained from field measurements may thus be made in terms of the anisotropic layering. In addition, apparent resistivities in orthogonal directions have been calculated for specific models and compared to experimental data. It is apparent that the large scatter of observed resistivities can be caused by small changes in the polarization of the magnetic field.

Capture of Magnetic Microspheres in Electrokinetic Flow for Application in Lab-on-Chip Devices

2012 ◽  
Author(s):  
Debarun Das ◽  
Marwan Al-Rjoub ◽  
Jagjit S. Yadav ◽  
Rupak K. Banerjee
Keyword(s):  
Magnetic Field ◽  
Electric Fields ◽  
Magnetic Beads ◽  
Magnetic Microspheres ◽  
Electrokinetic Flow ◽  
Lab On Chip ◽  
Micro Total Analysis Systems ◽  
Total Analysis ◽  
On Chip ◽  
The Magnetic Field

Isolation of bio-molecules, cells and pathogens for immunoassays is a critical component in micro total analysis systems (μTAS). Magnetophoretic technique is often used for separation of such target species, where magnetic beads tagged with specific antibodies against cell surface epitopes, are captured in the microfluidic device. In this study, a numerical model is developed for capture of beads under an external magnetic field in electrokinetically driven flow. The results indicate an increase in the number of beads captured when the magnetic field is higher and the flow is driven by lower electric fields.

scholarly journals Ion energy increase in laser-generated plasma expanding through axial magnetic field trap

2007 ◽  
Vol 25 (3) ◽  
pp. 453-464 ◽  
Author(s):  
L. Torrisi ◽  
D. Margarone ◽  
S. Gammino ◽  
L. Andò
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Electric Fields ◽  
Axial Magnetic Field ◽  
Ion Beam ◽  
High Vacuum ◽  
Target Surface ◽  
Axial Direction ◽  
Ion Interactions ◽  
The Magnetic Field

Laser-generated plasma is obtained in high vacuum (10−7 mbar) by irradiation of metallic targets (Al, Cu, Ta) with laser beam with intensities of the order of 1010 W/cm2. An Nd:Yag laser operating at 1064 nm wavelength, 9 ns pulse width, and 500 mJ maximum pulse energy is used. Time of flight measurements of ion emission along the direction normal to the target surface were performed with an ion collector. Measurements with and without a 0.1 Tesla magnetic field, directed along the normal to the target surface, have been taken for different target-detector distances and for increasing laser pulse intensity. Results have demonstrated that the magnetic field configuration creates an electron trap in front of the target surface along the axial direction. Electric fields inside the trap induce ion acceleration; the presence of electron bundles not only focuses the ion beam but also increases its energy, mean charge state and current. The explanation of this phenomenon can be found in the electric field modification inside the non-equilibrium plasma because of an electron bunching that increases the number of electron-ion interactions. The magnetic field, in fact, modifies the electric field due to the charge separation between the clouds of fast electrons, many of which remain trapped in the magnetic hole, and slow ions, ejected from the ablated target; moreover it increases the number of electron-ion interactions producing higher charge states.

scholarly journals Reconstruction of German Coastal Defense Line in 1942-1944 and Search for Military Historical Heritage Objects. Bolshoi Tyuters Island. Data of Geophysical Methods and Excavations.

2021 ◽  
pp. 144-161
Author(s):  
Aleksandr L'vovich Borisik ◽  
Evgeniy Vladimirovich Pyatigorskiy
Keyword(s):  
Magnetic Field ◽  
Sand Dunes ◽  
Geophysical Methods ◽  
Observation System ◽  
Metal Debris ◽  
Coastal Defense ◽  
Historical Heritage ◽  
Short Time ◽  
High Degree ◽  
The Magnetic Field

The article describes the results of full-scale geophysical 2017-2018 studies conducted with the purpose of detecting military historical heritage objects on Bolshoy Tyuters Island. Sand dunes located in the eastern part of the island were studied in a short time by detailed magnetic exploration with an observation step of about 1 m. The most interesting anomalies of the magnetic field were investigated with the georadiolocation method. The processed results provided for mapping the anomalous magnetic field and creating georadiolocation sections and a dimensional relief model which demonstrate anomalies related to German defense and are promising for further excavations. The pinpoint excavations of the identified anomalies made it possible to explain their nature and discover objects of historical value at depths of up to 5 m. Despite high "contamination" of the dunes with metal debris, the use of geophysical methods with a dense observation system made it possible to detect a large number of objects of military historical heritage and significantly reduce the volume of excavations. Linking of the German positions archival scheme at hand additionally provided for comparing the location of the objects found with symbols made on it. After systematization and generalization of all the information obtained during 4 years of research on the island, it is possible to reconstruct the system of German defense in the area of sand dunes with a high degree of reliability.

scholarly journals Time development of electric fields and currents in space plasmas

2006 ◽  
Vol 24 (3) ◽  
pp. 1137-1143
Author(s):  
A. T. Y. Lui
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Electric Fields ◽  
Time Development ◽  
Space Plasmas ◽  
Simplifying Assumptions ◽  
Electric Fields And Currents ◽  
Definition Of ◽  
The Magnetic Field ◽  
Made In

Abstract. Two different approaches, referred to as Bu and Ej, can be used to examine the time development of electric fields and currents in space plasmas based on the fundamental laws of physics. From the Bu approach, the required equation involves the generalized Ohm's law with some simplifying assumptions. From the Ej approach, the required equation can be derived from the equation of particle motion, coupled self-consistently with Maxwell's equation, and the definition of electric current density. Recently, some strong statements against the Ej approach have been made. In this paper, we evaluate these statements by discussing (1) some limitations of the Bu approach in solving the time development of electric fields and currents, (2) the procedure in calculating self-consistently the time development of the electric current in space plasmas without taking the curl of the magnetic field in some cases, and (3) the dependency of the time development of magnetic field on electric current. It is concluded that the Ej approach can be useful to understand some magnetospheric problems. In particular, statements about the change of electric current are valid theoretical explanations of change in magnetic field during substorms.

scholarly journals Observations of the Two-Level Structure of Sunspot Magnetic Fields

1971 ◽  
Vol 43 ◽  
pp. 231-234
Author(s):  
H. I. Abdussamatov
Keyword(s):  
Magnetic Field ◽  
Fine Structure ◽  
Level Structure ◽  
Field Structure ◽  
Short Time Scale ◽  
Sunspot Umbra ◽  
Magnetic Field Structure ◽  
Spectroscopic Information ◽  
Short Time ◽  
The Magnetic Field

Inhomogeneity of magnetic field structure, ‘granulation’ in sunspot umbrae and fine structure of the Evershed motions lead to the conclusion that the sunspot umbra is composed of magnetic ropes (or plaits) with dimensions near the limit of resolution. Progress in the study of these ropes is closely connected with the possibility of obtaining extensive spectroscopic information about some selected regions on the solar disc. It is extremely interesting to obtain a picture of short-time-scale variations of the magnetic field strength and the radial velocity field in connection with the transfer of energy from the photosphere to the upper layers of the solar atmosphere (chromosphere, corona).

scholarly journals Non-magnetic aspect sensitive auroral echoes from the lower E region observed at 50 MHz

1999 ◽  
Vol 17 (10) ◽  
pp. 1284-1292 ◽  
Author(s):  
R. Rüster ◽  
K. Schlegel
Keyword(s):  
Magnetic Field ◽  
Electric Fields ◽  
Middle Atmosphere ◽  
Magnetic Field Direction ◽  
Ionosphere Plasma ◽  
E Region ◽  
Strong Electric Fields ◽  
Gradient Drift ◽  
Drift Instability ◽  
The Magnetic Field

Abstract. Backscatter from E-region irregularities was observed at aspect angles close to 90° (almost parallel to the direction of the magnetic field) using the ALOMAR SOUSY radar at Andoya/Norway. Strong electric fields and increased E-region electron temperatures simultaneously measured with the incoherent scatter facility EISCAT proved that the Farley-Buneman plasma instability was excited. In addition, strong particle precipitation was present as inferred from EISCAT electron densities indicating that the gradient drift instability may have been active, too. Backscatter at such large aspect angles was not expected and has not been observed before. The characteristics of the observed echoes, however, are in many aspects completely different from usual auroral radar results: the Doppler velocities are only of the order of 10 m/s, the half-width of the spectra is around 5 m/s, the echoes originate at altitudes well below 100 km, and they seem to be not aspect-sensitive with respect to the magnetic field direction. We, therefore, conclude that the corresponding irregularities are not caused by the mentioned instabilities and that other mechanism have to be invoked.Key words. Ionosphere (plasma waves and instabilities; ionosphere irregularities; particle precipitaion) · Meteorology and atmospheric dynamics (middle atmosphere dynamics)

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