Torque and suspension force in a bearingless switched reluctance motor

Bearingless switched reluctance motors, which can control rotor radial positions with magnetic force, have been proposed. The bearingless switched reluctance motors are characterized by integration of switched reluctance motors and magnetic bearings. These motors have two kinds of stator windings composed of motor main windings and suspension windings in the same stator in order to produce suspension force that can realize rotor shaft suspension without mechanical contacts or lubrication. For successful stable operation, accurate theoretical formulas of instantaneous torque and suspension force are necessary to a rotational speed controller and a rotor radial position controller. This paper derives the theoretical formulas of the instantaneous torque and the suspension force from an assumption of simple permeance distribution. This derivation process makes an assumption that fringing fluxes are distributed on elliptical lines. It is shown with experimental results that the derived theoretical formulas are very accurate in terms of practical application. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(2): 72–82, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20157     

Subcomplementary code pairs: new codes for ST/MST radar observations

A new type of codes, named subcomplementary codes, are introduced. These codes are close to, but not strictly, complementary. Each of the two sequences of the pair has an equal number of opposite elements, which enables the codes to have very high interference-suppression-factor (ISF) performances in and around the radar center frequency. The disadvantage of these codes is the presence of sidelobes of amplitude of -N in their autocorrelation functions for lag 1 (N being the code length). Some properties of these codes are presented along with a technique for generating the code pairs. Subcomplementary code pairs have been found for values of N equal to 4, 8, 16, 20, and 32. A simulation study confirms a major improvement in ISF over complementary code pairs around the zero Doppler frequency. Experimental observations were performed with the middle and upper atmosphere radar in Japan using complementary and subcomplementary code pairs of length 16 and an uncoded pulse for range resolution performance comparisons. The results obtained so far indicate that the effects of the sidelobes in the subcomplementary code pair are minimal for wind observations, although significant for shear velocity observations. The degradation in performance in signal-to-noise ratio observations is found to be noticeable but not severe. The subcomplementary code pairs may, therefore, be used in situations where their advantages for interference suppression are exploited and where the effects of their weaknesses are not so important as in the case of observations for applications in meteorology.     

Killing effects of 5-fluorouracil on human biliary tract cancer cell lines

Previous studies have established that a partially quaternized derivative of chitosan, N-trimethyl chitosan chloride (TMC), can be used as an absorption enhancer for large hydrophilic compounds across mucosal surfaces. This study evaluates and compares the effects of the degree of quaternization of TMC, in a neutral environment, on the permeability of intestinal epithelial cells in vitro, where normal chitosan salts are ineffective as absorption enhancers. The effects of TMC-H [61.2% quaternized, (0.05-1.5% w/v)], TMC-L [12.3% quaternized, (0.5-1.5% w/v)], and chitosan hydrochloride [0.5-1.5% w/v] on the transepithelial electrical resistance (TEER) and permeability, for the hydrophilic model compound [14C]mannitol, of intestinal epithelial Caco-2 cell monolayers, were investigated at pH values of 6.20 and 7.40. The viability of the monolayers was checked with the trypan blue exclusion technique. At a pH of 6.20, all the polymers caused a pronounced reduction (37-67% at 0.5% w/v concentrations) in the TEER of Caco-2 cells. On the contrary, at a pH of 7.40, only TMC-H was able to decrease the TEER values, even in a concentration as low as 0.05% w/v (35% reduction). Comparable results were obtained with the permeation of [14C]mannitol. Large increases in the transport rate (18-23-fold at 0.5% w/v concentrations) were found at pH 6.20, whereas only TMC-H was able to increase the permeation of [14C]mannitol at pH 7.40 (31-48-fold at 0.05-1.5% w/v concentrations of TMC-H). For all the polymers studied, no deleterious effects to the cells could be demonstrated with the trypan blue exclusion technique. It is concluded that highly quaternized TMC is a potent absorption enhancer and the potential use of this polymer, especially in neutral and basic environments where normal chitosan salts are not effective, is expected to be an important contribution to the development of effective delivery systems for hydrophilic compounds such as peptide drugs.     

Life-threatening cardiac involvement throughout life in a case of Costello syndrome

A virus isolated from vaginal exudate of cows with vaginitis showed molecular weight around 92 to 143 x 10(3) KD, density between 1.168 and 1.203 g/ml and physical, chemical and morphological properties characteristic of virus belonging to the herpes group. This virus was not reagent with the fluorescent antibodies of Infectious Bovine Rhinotracheitis (IBR) or Parainfluenza-3 (PI-3) viruses, frequently detected in cows with vaginitis.     

A closed-loop operation of super high-speed reluctance motor forquick torque response

The authors examine operating modes of the cageless reluctance motor and propose a new control method for quick torque response. It is shown that the control of sinusoidal phase current in magnitude with fixed current phase angle provides a simple means for achieving quick torque response and efficient operation. The flux linkage, current, torque. and the rated voltage of the inverter are calculated for a reluctance motor. A performance comparison is made between the proposed control method and the field-oriented control method. Analysis and computer simulation show that substantial improvements in dynamic response and efficiency are achieved for a reluctance motor when operated with constant current phase angle compared with operation at constant direct axis current or constant flux. Test data from a 24000 r/min. 1.3 kW reluctance motor drive system are provided     

Dual polarization radar observations of anomalous wintertimethunderclouds in Japan

Dual-polarization radar observations of wintertime thunderclouds for the Sea of Japan are presented. The range-height-indicator (RHI) and plan-position-indicator (PPI) scans, respectively, reveal the height and horizontal distributions of ice particles, such as graupel and ice crystals. The overall shape of these ice particles is also confirmed on the ground. The ice crystals are, in general, found at high altitude near the cloud top, whereas the graupel is primarily seen near the center of clouds. The PPI display indicates a bandlike horizontal structure, and the lightning tends to occur around the bandlike gap where the ice crystals are, in advance, accumulated on the windward side of the preceding cloud. Simultaneous field mill observations indicate electric charge separation between these ice particles precipitating from the thunderclouds