Torque Ripple Minimization in a Switched Reluctance Drive by Neuro-Fuzzy Compensation

Simple power electronic drive circuit and fault tolerance of converter are specific advantages of SRM drives, but excessive torque ripple has limited its use to special applications. It is well known that controlling the current shape adequately can minimize the torque ripple. This paper presents a new method for shaping the motor currents to minimize the torque ripple, using a neuro-fuzzy compensator. In the proposed method, a compensating signal is added to the output of a PI controller, in a current-regulated speed control loop. Numerical results are presented in this paper, with an analysis of the effects of changing the form of the membership function of the neuro-fuzzy compensator.Comment: To be published in IEEE Trans. on Magnetics, 200

Spectral Caracteristics of Balmer Series Lines in Dense Hydrogen Plasma Produced by a Linear z-Pinch Discharge

The excited level population of hydrogen in dense plasma has been calculated by the collisional-radiative model. We took the ion density and the ground-state atom density as parameters, instead of assuming an ionization balance. We have found that, in the ionizing phase, the population density follows the distribution proportional to p-4.1 (p is the principal quantum number of the exited level.) In the recombining phase it is proportional to p2.3. The Balmer series spectrum corresoponding to these phases has been calculated, where the Stark line broadening and the continuum emissions were taken into account. It was found that these spectra differ substantially from each other. By using an optical multichannel analyzer, the Balmer series spectrum has been observed from a z-pinch plasma. The spectrum taken at the time of the maximum compression is consistent with the recombining plasma. On the basis of the above finding, we discuss the problem of the “transparency window” : a substantial reduction of the emission intensity near the series limit, which has been observed in dense plasmas. We conclude that our spectrum of the ionizing phase plasma could account for the apparent transparency window so far reported

Characteristics of Two Types of Grazing Incidence Spectrometers with Holographic Gratings

Two types of grazing incidence spectrometers have been constructed which are applicable to photographic and photo-electric recordings of emission spectra of plasmas in the extreme ultraviolet. The spectrometer SGX-100 with a 1-m Rowland circle covers the wavelengths of 30 to 1500 Å with both a holographic grating (HG) and a ruled one (RG). In this spectrometer, the incidence angle cc to the gratings is continuously variable from 80°to 86°, where the inverse Vodar mounting is adopted to keep a constant line of sight of the spectrometer against a light source. The small grazing incidence spectrometer GIT-30 with a toroidal holographic grating covers the wave-lengths of 150 to 1600 Å. The wavelength scanning is performed by a simple rotation of the grating under a constant angle 142° between the incident and exit beams. These spectrometers were used to observe spectra of emissions from a hollow cathode lamp and linear Z-pinch and plasma-focus discharges. Characteristics of the spectrometers are discussed on the data observed

Three Bianthraquinone Derivatives from the Mangrove Endophytic Fungus Alternaria sp. ZJ9-6B from the South China Sea

Three new bianthraquinone derivatives, alterporriol K (1), L (2) and M (3), along with six known compounds were obtained from extracts of the endophytic fungus Alternaria sp. ZJ9-6B, isolated from the mangrove Aegiceras corniculatum collected in the South China Sea. Their structures were elucidated by one- and two-dimensional NMR spectroscopy, MS data analysis and circular dichroism measurements. Compounds 1, 2 and 3 were first isolated alterporriols with a C-2–C-2′ linkage. The crystallographic data of tetrahydroaltersolanol B (7) was reported for the first time. In the primary bioassays, alterporriol K and L exhibited moderate cytotoxic activity towards MDA-MB-435 and MCF-7 cells with IC50 values ranging from 13.1 to 29.1 μM

Investigation of the effect of articulatory-based second language production learning on speech perception

International audienceThe effect of second language production training on perception has been previously explored, but it remains unclear whether such training by itself influences the perception of speech sounds. In previous work participants heard the correct pronunciation of the target while simultaneously undergoing production training, making it unclear what component of improvement was due to the production training alone. In the current study we have therefore modified our electromagnetic articulometer-based training system, which provides estimates of learner-specific head-corrected tongue positions for a target utterance in real time, to eliminate simultaneous presentation of audio stimuli. Japanese learners of the American English vowel /ae/ performed ABX perceptual testing on this vowel before and after the visually presented articulatory-based pronunciation training. We examined whether or not the production-driven pronunciation improvement also induces a change in the perception of the second language sounds

Role of adsorption kinetics in the low-temperature Si growth by gas-source molecular beam epitaxy: In situ observations and detailed modeling of the growth

科研費報告書収録論文(課題番号:12650025・基盤研究(C)(2)・H12～H13/研究代表者:末光, 眞希/有機ケイ素を用いたSiCエピタキシャル成長の表面化学

Emission from C-, N- and O-Impurity Ions in Linear Pinch He Plasma in Vaccum Ultraviolet λ500 to 1,500A Region

The He plasma containing C-and O-impurity ions or N-impurity ions, whose electron density and temperature ranged from 5 × 10¹⁷ to 3 × 10¹⁸cm⁻³ and from 4 to 5 eV, respectively, was produced from He-CO₂ (0.1 mole%) or He-N₂ (0.1 mole%) mixed gas, respectively, in a linear pinch tube, and the observed emission lines in λ500 to 1, 500A region were assigned and classified ; the lines due to the outer 2ₛ-shell electron excitation and those due to the valence 2p-electron excitation for OII-ions, NII-and OIII-ions and CII-, NIII-and OIV-ions, which are specified by the ground state configurations 2ₛ²2pᵐ with m＝3, 2 and 1, respectively, and the lines from the singly and doubly excited levels for CIII-, NIV-and OV-ions, which have the ground state configuration 2S². The relative intensity, the pressure dependence of intensity and the temporal behavior were observed on the spectral lines of both the outer 2ₛ and the valence 2p excitations. A possibility is suggested that the charge exchanges between He⁺ and impurity atoms or ions take place due to the rapid contraction of the plasma. For CIII- NIV-and OV-ions, it is seen that the lines from the doubly excited level 2p²(³P) to the metastable levels 2ₛ2p(³P⁰) show a remarkable afterglow after the pinch of the plasma