Abstract: In the polymerization of olefins using a catalyst comprising an organoaluminum compound and solid catalyst components containing titanium and/or vanadium; and magnesium in a vapor phase fluidized bed, the formation of sheet-like polymer and other abnormal conditions in the initial stage of the polymerization are avoided by means of previous drying of the reactor by feeding an organoaluminum compound prior to the feeding of seed polymer, the quantity of said organoaluminum compound being calculated by the following equation (I):A=k.multidot.V.sup. 2/3 (I)wherein A is the feed quantity (mol) of the organoaluminum compound, k is a coefficient (mol/m.sup.2) in the range from 0.15 to 4, and V is the volume (m.sup.3) of the whole system including gas circulation pipings.

Abstract: A process for producing polyolefin with a vapor-phase fluidized-bed reactor, wherein the reaction is started after filling the reactor with particles which contain moisture and/or molecular oxygen and can form a fluidized bed in order to prevent the formation of molten resin which is liable to occur at the start of the reaction and to attain a smooth operation of the reactor.

Abstract: A process for producing polyolefin with a vapor-phase fluidized-bed reactor, wherein the reaction is started after filling the reactor with particles which contain moisture and/or molecular oxygen and can form a fluidized bed in order to prevent the formation of molten resin which is liable to occur at the start of the reaction and to attain a smooth operation of the reactor.

Abstract: This invention relates to a bed having a base, a mattress, and a system for moving the mattress up and down for helping a person make the bed, and can be preferably adapted in a guest room of hotels or the like. The present invention provides a bed comprising a base, a mattress provided on a top face of the base, a pair of inflatable means provided between the mattress and the base, and an air-supplying tube connected with said inflatable means, wherein one of the inflatable means is laid on one side of the top surface of the base, while the other is laid on the other side of the top surface of the base, and each inflatable means is independently connected to an air-supplying means through the air-supplying tube.

Abstract: A process for feeding a powder catalyst with a gas intermittently to a high-pressure fluidized bed reactor for the vapor phase polymerization of olefin, wherein the cross section of a catalyst feed pipe is reduced midway through the pipe to thereby make continual catalyst feeding possible and prevent the formation of a lump polymer.

Abstract: This invention relates to a bed having a base, a mattress, and a system for moving the mattress up and down to help a person to make the bed, which can be preferably adapted in a guest room of hotels or the like. The present invention provides a bed comprising a base, a mattress provided on a top face of the base, at least one inflatable means provided therebetween, and an air-supplying tube connected with a part of the inflatable means, wherein the inflatable means has a plurality of inflatable parts and a plurality of non-inflatable parts, each non-inflatable part is alternatively provided between the inflatable parts so as to communicate to each other to make a loop around an outer peripheral portion of the top face of the base.

Abstract: A process for feeding a powder catalyst with a gas intermittently to a high-pressure fluidized bed reactor for the vapor phase polymerization of olefin, wherein the cross section of a catalyst feed pipe is reduced midway through the pipe to thereby make continual catalyst feeding possible and prevent the formation of a lump polymer.

Abstract: A baby carriage which can be used not only as a two-wheel-steered baby carriage but also as a four-wheel-steered baby carriage whose front and rear wheels can be swung to steer the carriage. Brackets having slender horizontally extending through-holes, through which the rear axle of the baby carriage extends so as to be swingable along the holes, are attached to the lower ends of right and left rear legs and are secured to a coupling plate extending from one of the brackets to the other. The rear axle has a length such that the axle extends from one of the brackets to the other. The rear axle is pivotally supported at the longitudinally central portion of the axle by the coupling plate so that both ends of the axle extending through the slender horizontally extending throughholes of the brackets at the ends of the axle can be swung in mutually different directions. The rear wheels are attached to the rear axle at both ends thereof. Swinging of the rear axle can be freely prevented by the brackets.

Abstract: A video recording and reproducing apparatus comprises a line sensor camera having a line scan image sensor which is scanned along a predetermined standard line and receives an image of a moving object passing the standard line. An output video signal of the line sensor camera is converted by an A/D converter into a series of picture element data which are successively stored into a video memory to form therein a plurality of pictures. A control circuit selects in accordance with selection information supplied from a control box a desired one of the plurality of stored pictures, and reads the picture element data of the desired picture from the video memory. The picture element data thus read from the video memory are successively converted into analog video signals which are supplied through a mixing circuit to a display unit to thereby display the picture on the display unit.

Abstract: A shutter for use in a television camera, including: a casing having a first wall having a first opening formed therethrough for allowing incident light from a lens of the television camera to pass through the first opening and a second wall opposingly disposed to the first wall and having a second opening aligned to the first opening for allowing the incident light to pass through the second opening into a body of the television camera; a first disc member supported within the casing to be rotatable about an axis thereof and in parallel with the first and the second walls, the first disc member having a first shutter hole formed therethrough; a second disc member supported within the casing to be rotatable about an axis thereof and in parallel with the first and the second walls, the second disc member having a second shutter hole formed therethrough, the first disc member and the second disc member being disposed to overlap at overlapping areas at peripheries thereof with a gap, the first and second shutter