Abstract: A levitator which is mounted on a space station; for example, for use in material science experiments in space. The levitator has a position detector for detecting the position of a sample, a variable power supply whose output voltage varies in accordance with the signal output from the position detector, a pair of planar electrodes connected to two ends, respectively, of the variable power supply and disposed in opposing relation to each other, and a ring electrode disposed so as to surround each of the planar electrodes and to which is applied a higher voltage than that applied to the corresponding planar electrode from a DC power supply, thereby holding the sample stationary at a desired position by means of the planar and ring electrodes. The levitator further has a means for rotating the sample being held stationary. Thus, it is possible to rotate the sample in a controlled manner and hence possible to carry out an experiment in which the sample is uniformly heated in a microgravity environment.

Abstract: An electromagnetic actuator includes a cylindrical rod made of a magnetic substance and having a large number of annular teeth formed on an outer surface thereof at a fixed pitch, and a plurality of annular electromagnets fitted on the cylinder rod. The intervals of the annular electromagnets are set such that the offsets between the annular teeth of the annular electromagnets and the annular teeth of the corresponding cylindrical rod gradually increase. This ensures highly accurate axisymmetric configuration which in turn ensures a completely axisymmetric distribution of the magnetic flux. In consequence, the radial force which acts between the electromagnet and the rod can be reduced, and control over the movement of the rod in the axial direction is thus facilitated.

Abstract: An electromagnetic wave shielding system for an optical sensor includes: a sensor body having an aperture through which an optical signal is made incident on the sensor body; a shielding plate disposed within the sensor body, the shielding plate having an opening having a dimension of at most about one-half of the wavelength of electromagnetic waves; an optical system for gathering the optical signal which passes through the aperture of the sensor body to the dimension of the opening in the shielding plate so that it can pass through the opening; and a detecting/processing unit for detecting and processing the optical signal which passes through the opening in the shielding plate. Thus, the electromagnetic waves which have entered are prevented from passing through or are remarkably attenuated by the opening in the shielding plate, and are thereby prevented from reaching the detecting/processing unit.

Abstract: An electrically scanning microwave radiometer for measuring the brightness temperature of an object by performing a conical scan of the object. The microwave radiometer comprises a torus-type reflector and an array of radiators. The radiators are grouped to form a plurality of subarrays. The beams formed by the respective subarrays are correspondingly switched to perform the conical scan on the surface of the object. The signals received by the radiators during the conical scan are arithmetically operated to obtain the brightness temperature value of the object located within the width of the antenna beam.

Abstract: An intermediate layer made of an Si.sub.1-X Ge.sub.X mixed crystal layer is formed on an Si crystal substrate, where the character X denotes a value in the range of 0 to 1. The intermediate layer is connected to the substrate via a heterojunction generating a first heterojunction barrier. An Si crystal layer is formed on the intermediate layer and is connected to the intermediate layer via a heterojunction generating a second heterojunction barrier. The substrate, the intermediate layer, and the Si layer form a laminated structure. The first and second heterojunction barriers form a charge storage well in an energy band of the intermediate layer. Charges in the well are excited by absorbing infrared light. The intermediate layer contains unevenly-distributed impurities whose concentration montonically varies in a direction along a thickness of the laminated structure. The variation in the concentration generates an internal electric field in the energy band of the intermediate layer.

Abstract: An end effector secured to an front end of a manipulator of a remote manipulator system and having a function for clamping dedicated objects, wherein a force (or torque) applied to the end effector at the time of clamping the dedicated object is detected so that a driving portion of the end effector is feedback-controlled in order to protect the end effector from being applied with a force (or torque) exceeding a predetermined level.

Abstract: A pumping system comprising a liquid ring vacuum pump including a casing and a rotatable runner. A Pitot pump including a casing, a Pitot tube, an impeller and a drum, the impeller and the drum being rotatably mounted in the casing, and the Pitot tube being mounted within the casing adjacent the outer periphery thereof. A gas passage leads into the vacuum pump, from the vacuum pump into the Pitot pump, and out of said Pitot pump, and a liquid passage leads from the Pitot tube to the vacuum pump. The system further includes a cooler connected to the liquid passage for cooling liquid therein, and a drive motor coupled to rotate the runner, the impeller and the drum.

Abstract: An infrared sensor includes a metal and a semiconductor contacted to each other via a rectifying potential barrier. The semiconductor includes a p-type strained Si.sub.1-X Ge.sub.X epitaxial layer grown on a p-type substrate, wherein the character X denotes a Ge atomic fraction and wherein X increases from zero to a predetermined upper limit in a direction away from the Si substrate toward the metal. The metal may be selected from the group of Pt, an alloy of Pt and Si, and an alloy of Pt, Si, and Ge. In addition, the metal may also be selected from the group of Ir, an alloy of Ir and Si, and an alloy of Ir, Si, and Ge.

Abstract: The present invention is related to a liquid fuel rocket engine of the type that a liquid fuel is boosted in pressure by way of a booster means.