No abstract

No abstract

A lot of industrial equipment and household electric appliances have diode rectifier circuits for the dc voltage source of the inverter circuits. However, the input current waveform of the diode rectifier circuit is distorted. To avoid this problem, PFC converter have attracted considerable attention. However, the system configuration is complication compared with that of the diode rectifier circuit.On the other hand, the single-phase or three-phase distribution system with the rectangular voltage waveform has been proposed. The distribution system with the rectangular voltage waveform is useful for the equipment with the dc voltage source because the high input power factor is obtained by using the diode rectifier circuits whose system configuration is simple.This paper presents a single-phase PFC converter for both the distribution systems with the sinusoidal or rectangular voltage waveform. Also, this paper presents an input voltage estimation because it is necessary to judge between the sinusoidal and rectangular voltage waveforms and to obtain the high input power factor. Figure 1 shows the rectangular input voltage waveform. The function recθ is defined as the rectangular waveform of which the Figure 2 shows the system configuration of the single-phase PFC converter for both sinusoidal and rectangular input voltage waveforms. The control purpose of PFC converter is the realization of the unity effective power factor and the stable output dc voltage.The amplitude E RM (n) and the phase angle θ RM (n) of the rectangular input voltage can be estimated with the estimation error of the input voltage ∆e R (n − 1) in (1) and (2)where K RE and K Rθ are the gains for the estimation of the amplitude and the phase angle, respectively. ω R is the angular frequency of the input voltage and T c is the control period. Figure 3 shows the convergence characteristics for the phase angle disturbances of −180 ∼ +180 deg.Using the proposed scheme, the input voltage estimation algorithm can converge the estimation errors within 40 ms of the input voltage for the amplitude and phase angle disturbances. The power factors are 0.995 and 0.949 when the sinusoidal and rectangular waveforms are used as the input voltages, respectively. Takaharu Takeshita * MemberThe distribution system with the rectangular voltage waveform is useful for the electrical equipment with the dc voltage source because the high input power factor is obtained by using the diode rectifier circuits. This paper presents a single-phase type AC/DC converter using a novel power factor correction (PFC) technique to realize the unity effective power factor and stable output dc voltage for both the distribution systems with sinusoidal or rectangular voltage waveform. Also, this paper presents the estimation and judgment of the input voltage waveform and its stability and the design of the estimation gains. The new control strategy has a notable advantage that it is flexible for both sinusoidal and rectangular waveforms to realize the good characteristics. The effecti...

We observed by immunofluorescence microscopy the distribution of cytoskeletal filaments in the superficial cells (SP cells) of rat urinary bladder epithelium in a distending state. To precisely detect SP cell fluorescence, the cells were separated from the distended bladder epithelium by scraping with a glass slide after paraformaldehyde fixation. Each cell appeared characteristically polygonal and flattened. In these cells, F-actins were predominantly distributed at the lateral cell border, marking the cell boundary. They also formed fine networks in the inner cytoplasm. Cytokeratin filaments were distributed in two characteristic patterns: they marked cell boundaries as did F-actin, and they formed thick circular bundles between the nucleus and cell margin. These two types of keratin filaments were also connected by thin filaments. These cytokeratins contained at least cytokeratin 18 subunit. Numerous microtubules were distributed evenly in the cytoplasm forming fine networks, except near the cell periphery.These observations show that SP cells are supported mainly by cytokeratin networks.

The purpose of this study was to determine the differences in electromyographic activities of hemiplegic stroke patients who succeeded and failed the sit-to-stand (STS) during the recovery phase. [Participants and Methods] Twenty stroke patients who succeeded in the STS, and 20 stroke patients who failed in the STS participated in this study. Leg muscle activation times from the time of seat-off during the STS were analyzed using surface electromyography. The differences between the groups were compared. [Results] The tibialis anterior, rectus femoris and biceps femoris activated before seat-off in both groups. However, in the failed group the gastrocnemius also activated before seat-off. Activation of the gastrocnemius was significantly earlier than in the success group. Furthermore, in the failure group, the activation of the muscles of the hip and ankle joints occurred almost at the same times. [Conclusion] These results suggest that the cause of stroke patients failing the STS is these abnormal muscle activation patterns.