The present study aims on the fabrication of hybrid epoxy composite with zero-dimensional (0D) filler nitrogen-doped carbon dot (N-CDs) and short carbon fiber (SCF) for the electromagnetic interference (EMI) shielding in the X-band frequency. The scanning electron microscope microstructure study has revealed that the SCF is strongly adhered to the epoxy without aggregations. The Dielectric response study indicates an increase in complex permittivity with the addition of N-CDs filler due to an increase of interfacial region between epoxy and the filler. The shielding effectiveness (SE) has enhanced to 35.7 dB for 3 wt.% loading of N-CDs to SCF of 5 wt.% in the epoxy matrix (SCF-CD3). The N-CDs loaded composites led to an increase in both the shielding by reflection and absorption due to the enhancement of interfacial adhesion and electrically conductive network in the epoxy matrix. Additionally, the mechanical properties such as storage modulus, glass transition temperature, and thermal conductivity is improved in the N-CDs loaded composites. It has been observed that the SCF-CD3 sample show high EMI shielding effectiveness with better mechanical and thermal properties.

The ringing due to cable resonance in contact discharge waveforms is verified by contrasting the frequencies of variations in the “transfer impedance” of an ESD generator, which is newly defined in this paper as the rate to a test voltage in the Laplace domain of the complex spectrum of the contact discharge current waveform, with those calculated from an IEC specified simplified equivalent circuit of the ESD generator using the measured return cable impedance Z_R and charging cable impedance Z_C at one end grounding in the IEC calibration environment. The transfer impedances obtained from the contact discharge measurement waveforms with and without the 2 m return cable present are compared with those from the measured impedances Z_R and Z_C of the one end grounded return cables under the IEC specified arrangement and the same arrangement as the charging cable, respectively. The result shows that the transfer impedances are confirmed to have impedance variations in the frequency range from 40 MHz to 200 MHz, which fairly correspond to the frequencies of variations in the transfer impedance calculated from the parallel impedance between the return cable and the charging cable with one end grounded. Furthermore, comparison of the transfer impedances for the measured impedances of return cables shorter than 2 m length, which are not specified by the IEC standard, with the corresponding transfer impedances for the measured contact discharge waveforms, indicates that both frequencies of the first resonance peaks are in good agreement and ringing reduces in the subsequent frequency range. In view of the fact that the transfer impedance from 40 MHz to 200 MHz can approximately be expressed as (R_B+Z_R//Z_C) where R_B having a typical value of 330 Ω is the IEC specified discharge resistance of the ESD generator, the above finding validates that the transfer impedance variations causing ringing mainly result from the parallel resonance between the return cable and the charging cable.

Plasma behavior in cesium-seeded argon (Ar/Cs) and xenon-seeded argon (Ar/Xe) disk-shaped MHD generators is compared under almost the same working conditions using r-θ two-dimensional simulation. For both working gases, uniform plasma occurs at the optimum load resistance, and the power outputs are the same under an identical inlet ionization degree. For Ar/Cs, plasma is stable and uniform in the range of electron temperature of 4300~5800 K basically according to the linear perturbation theory. In the actual plasma in MHD generator, however, the uniform plasma still can be maintained even at higher electron temperature due to the low three-body recombination coefficient of Ar. For Ar/Xe, on the other hand, uniform plasma is maintained when the characteristic time of the electron number density is longer than the residence time of the working gas where the electron temperature is around 4300~8600 K, even though unstable plasma is suggested from the linear perturbation theory.

In this report, the validity of the theoretical formula for the magnetic force acting on a steel ball from a Magnetic guiding magnet is examined by t-test. Also, considered whether the theoretical formula can be applied to the calculation of the magnetic force. As a result, the validity was shown because there was a very strong correlation between the analytical value and the calculated value of the magnetic force at the significance level α of 1%. Then, it was suggested that the calculation by the theoretical formula of the magnetic force can be applied at 80 < l ≤ 120 mm. And the constant of the capsule endoscope estimated as 1.8×10^-12 H･m².