Showing papers by "Mitsubishi Electric published in 1972"

A beam-waveguide feed having a symmetric beam for Cassegrain antennas

Abstract: The asymmetric reflectors are unavoidable in the composition of a beam-waveguide feed and generally cause asymmetry of the beam from the feed. By means of the combination of two suitable asymmetric reflectors a rotationally symmetric beam can be obtained on the basis of geometrical optics.

Voltage Escalation in the Switching of the Motor Control Circuit by the Vacuum Contactor

Abstract: A turn-to-turn fault of a high-voltage motor which was controlled by a vacuum contactor prompted this study. The study revealed that a voltage escalation can certainly occur by the repetition of re-ignitions as indicated by recent several papers,1,2, but the cause of the escalation is different from that reported. This paper presents a new theory for the voltage escalation, makes clear the conditions for the occurrence of the escalation, and leads to the conclusion that protectors are indispensable in the application of the contactors to the motor control circuit.

Differential amplification magnetic sensor

Abstract: The differential amplification magnetic sensor (DAMS) comprises a rectangular Hall device and two transistors. These three elements are not only integrated as a monolithic IC, but are also made smaller by using the Hall region as the common base of the transistors, the collectors of which are used to isolate the Hall region from the substrate. Relations between electromagnetic characteristics of the DAMS and impurity atom density and effective thickness of the Hall region are analytically described, assuming a simplified model. Numerical calculation shows that a magnetic sensitivity of higher than 10 V/kG (with a load resistance of 10 kΩ) and a noise-equivalent magnetic flux density of less than 0.1 m/Hz1/2can be obtained when the effective thickness of the Hall region and its impurity atom density are well designed. Two types of test samples were fabricated. One, made by triple diffusion, had a Hall region with impurity atom density of 8 × 1018cm-3and effective thickness of 3.2 µm; the other, made by diffusion and epitaxial growth, had values of 2 × 1016cm-3and 3.3 µm, respectively. These prototypes were found to have magnetic sensitivities of 0.5 V/kG and 12 V/kG (with load resistances of 100 kΩ), respectively, when exposed to static magnetic fields. The constancy of the magnetic sensitivity is better than ten percent for magnetic flux densities below 2 kG.

Detection of sulphur dioxide in stack plume by laser Raman radar

Abstract: Laser Raman radar offers a promising approach to the remote sensing of atmospheric pollutants in stack plume. An analysis revealed that the combination of the second harmonic of a Nd:YAG laser, a synchronous single photoelectron counting (SSPC) scheme, and narrow passband interference filter employed for light source, signal processor, and separation of Raman-scattered light respectively gave the most sensitive system for stack effluent monitoring. Using a laser Raman radar constructed on the basis of the analysis, the concentration of SO2 in the plume emitted from a 150 m high stack of a power plant was measured at a distance of 228 m.

Electrooptic Light Beam Deflection with Sr 0.75 Ba 0.25 Nb 2 O 6 Prism

Abstract: An experimental investigation was performed on the electrooptic light beam deflection with a Sr0.75Ba0.25Nb2O6 isosceles prism at 6328 A. Although measured deflection angle was large (e.g. 3m rad. for an electric field of 6 kV/cm), deflection characteristic was considerably nonlinear and what is called butterfly hysteresis loop was observed in the ferroelectric phase. Sign and magnitude of the polarization were easily changeable and the coercive field was found to be as low as 1.3 kV/cm at 33°C. The electrooptic effect is dominated by a quadratic term with respect to the polarization. The unclamped value of the quadratic electrooptic g-coefficient g33 was determined to be 0.14 m4/C2. An electrically-induced spot distortion was observed, which was most remarkable at the polarization reversal.

Levitation performance of magnetically suspended high speed trains

Abstract: Analyses have been made of the design parameters which affect the magnetic lift and drag forces on the magnetically suspended very high speed train models of practical interest. In the suspension systems investigated here, the superconducting magnets are installed in the train and the roadbed is equipped with normal-conducting coils. As a result of this investigation, an improved suspension system is proposed, which consists of "ladder-type conductor" in the roadbed. This new system is investigated theoretically.

Laser frequency fluctuations due to mechanical vibrations

Abstract: The frequency fluctuations of a single-frequency laser due to mechanical vibrations are dependent on the sound pressure and sound frequency. The two dependences have been studied with the observation of beat signals between two stable external-mirror He-Ne lasers in the free-running condition. The dependence on the sound pressure follows Hooke's law, so that the difference between the frequency fluctuations due to the acoustic noises and those due to the external vibrations was quantitatively distinguished. Some causes of mechanical instability of the laser were clarified from the dependence on the sound frequency as compared with the lowest natural frequencies of each mechanical element in the cavity. The translation of mirrors along the optical cavity axis and two rotations of mirrors about the axis perpendicular to the optical cavity axis, which give rise to the variation in the relative angle between the laser beam axis and the Brewster window plate, are the most dominant motions that cause frequency fluctuations of the laser.

Video information recording media and apparatus for reproducing video information

Abstract: A video information recording media and apparatus for reproducing video information recorded on the media is provided. A luminance signal Y and a color signal (R-Y) is recorded on one side of the recording media and a luminance signal Y and a color signal (B-Y) is recorded on an adjacent side of the recording media. The color video information upon the recording media is reproduced by the use of a flying spot scanner which horizontally scans the recording media and alternately reads the Y and (R-Y) signal and the Y and (B-Y) signal and by the use of a delay is able to compose the desired information therefrom.

Sequential Permutation Networks

Abstract: Two sequential permutation networks which generate all nǃ permutations without duplication are presented. Each permutation can be derived from its predecessor autonomously in one clock step. Based on the principle of recursive execution of a product of transpositions, the first network is constructed in multiple cascades of ½(n²-n) switching elements each of which permutes its input pair to its output pair according to its internal state, and is controlled sequentially by the same principle. Next, the network whose structure and control sequence are complementary to those of the first is presented. The first is named a cyclic permutation network and is an explicit representation of a mapping function The second is named a lexicographic permutation network and is an explicit representation of a factorial counting function where ah is a h-nary factorial digit 0 ≤ ah ≤ (n-1). The characteristics of the networks are investigated by establishing a one-to-one correspondence among nI integers, n! permutations, and n! states of the networks. For the lexicographic permutation network which can generate all permutations in lexicographic order, three examples of applications are given.

Optical detection of magnetic resonance in alkali-metal, vapor using d(1) and d(2) radiation simultaneously.

Abstract: Change in polarization produced by circularly polarized D1 + D2 radiation and destroyed by the resonance can be observed by monitoring the intensity of the radiation transmitting the vapor. The polarization and intensity of the absorption signal (change in absorption of the radiation produced by the resonance) are calculated from the solutions of equations governing the rate at which the populations of Zeeman sublevels of the ground state change. The result shows that the polarization increases as the disorientation mixing in the excited state decreases, and that the signal intensity is nearly equal to that when the D1 radiation was used alone. Signal representation derived by Bell and Bloom based on Bloch’s equations is modified so as to be applied to the experiment using D1 + D2 radiation as well as to that using D1 radiation alone. The calculated result from the representation shows that the amplitude of the modulation signal (rf light modulation at the resonance) for D1 + D2 radiation is also nearly equal to that for D1 radiation alone.

Development of A. C. Type "System Interconnectors"

Abstract: This paper is concerned with the System Interconnector, a new development for preventing spread of disturbances and reducing short circuit capacity in a large-scale power system where power demand is ever increasing. Background where such development is required, functional requirements, results of analytical and experimental studies, and feasibility of practical schemes are discussed. Also described are 66kV prototypes of the System Interconnector.

Considerations of Transient Recovery Voltages in Connection with the Modern Circuit Breaker Testing

Abstract: Technology is always facing to the increasing requirements from industry in the field of testing power circuit breakers. In order to cope with the growing capability of breakers required and to meet the accumulation of more precise knowledge of modern age, continuing review on the basic process of testing is always of essential importance. In the paper some fundamental problems concerning transient recovery voltage are discussed in connection with the short circuit testing of modern power circuit breakers. The validity and usefulness of combined application of unit test and synthetic test are demonstrated based on some recent studies in the laboratory authors are associated with.

A 6 GHz rotating field phaser

Abstract: A 6 GHz improved rotating field phaser, which consists of a circular waveguide loaded with a ferrite tube containing a metal rod coaxially, is described. In order to design the phaser, the differential phase shifts of the phaser have been calculated by a perturbation method under some assumptions, resulting in good approximate values. The phaser constructed for trial is shown to have an insertion loss of less than 0.6 decibels over an 8 percent frequency band.

Security of Seismic Construction of High Voltage Switchgear

Abstract: There has been a growing awareness in the electrical power industry of the necessity of protecting high voltage switchgears against anticipated severe earthquakes. The authors have accumulated data from a number of investigations into the seismic construction of this equipment. In addition, experiments conducted with a powerful hydraulic shaking table have confirmed the pertinence of the analytical data. These data have resulted in a practical and effective method of insuring the seismic design of high voltage switchgear. Many different types of high voltage power circuit breakers and gas insulated compact substations (GIS) have been constructed based on these procedures, and the security of this equipment has been verified during several recent earthquakes in Japan.