Abstract: A method for controlling the thickness of a single crystal thin-film silicon layer bonded on a dielectric substrate in a SOI substrate thereby effecting conversion of said single crystal silicon layer to a thin film is disclosed. To be more precise, said method comprises selectively and hypothetically dividing the entire surface of said single crystal silicon layer destined to undergo a chemical vapor-phase corrosion reaction for the sake of said conversion into necessary minute sections and, at the sametime, taking preparatory measurement of the thickness of said single crystal silicon layer in each of said minute sections, and effecting on each of said minute sections said conversion to a thin film by a chemical vapor-phase corrosion reaction adjusted in accordance with the measured thickness of layer. The conversion to a thin film is attained with the dispersion of thickness of the single crystal silicon layer controlled with high accuracy.

Abstract: Single crystal silicon islands in a dielectric-separation substrate are separated completely and finished in a uniform thickness by preparatorily denuding a single crystal silicon substrate of a warpage suffered to occur therein.This dielectric-separation substrate is produced by a method which comprises forming a thermal oxide film on a single crystal silicon substrate having grooves incised in advance therein, then forming an irreversibly thermally shrinkable film on the rear surface of said single crystal silicon substrate prior to depositing a polycrystalline silicon thereon, then depositing a polycrystalline silicon on said single crystal silicon substrate, and thereafter grinding said single crystal silicon substrate in conjunction with said irreversibly thermally shrinkable film.

Abstract: After the separating grooves has been formed, the polycrystalline silicon deposited as bonded to the single crystal substrate as a supporting base, and the polycrystalline silicon layer ground and polished until the oxide film in the area other than the separating grooves is exposed, the present invention etches the polycrystalline silicon layer on the separating grooves with mixed acid composed of hydrofluoric acid and nitric acid until its thickness equals that of the separating oxide film and subsequently removes the oxide film in the area other than the separating grooves with hydrofluoric acid, As a result, the otherwise inevitable occurrence of projections of polycrystalline silicon can be precluded. When the dielectric-separation substrate obtained by the present invention is used in manufacturing a semiconductor device, therefore, the occurrence of particles due to the chipping of the projections of polycrystalline silicon and the breakage of distributed wires in the produced device can be prevented.

Abstract: In a VTR having a rotary head cylinder (20) having four magnetic heads with 90.degree. angular pitches inbetween on a cylindrical surface thereof, a magnetic recording tape is helically wound around the rotary head cylinder (20), a motor to drive the rotary head cylinder (20) is servo-controlled by utilizing output signal of a phase comparator (10) which compare a first frequency divider (62) to divide frequency of output signal of a rotation phase detector (7) into N/(2N-2) times and an output signal of a second frequency divider (61) for dividing frequency of vertical synchronization signal (S.sub.v) of video signal into 1/2 times, and thereby accurate phase control of the rotary head cylinder is attainable.

Abstract: The semiconductor device comprises a semiconductor substrate, a plurality of spaced active elements, for example, of a planer type formed on one surface of the substrate, and a supporting plate bonded to the opposite surface of the substrate. A groove is cut through the substrate to reach the supporting plate for isolating the active elements.

Abstract: A composition for filling the spaces in bores penetrating walls and floors of buildings and having electric wires and cables extending therethrough or for filling the clearances at the joints of interior finishing materials of buildings. The composition comprises (a) 100 parts by weight of a curable polychloroprene in a liquid state at room temperature, (b) about 200 to about 700 parts by weight of a hydrated metallic oxide, and (c) about 20 to about 100 parts by weight of a heat-resistant fibrous material. The components (b) and (c) are contained in a combined amount of at least about 250 parts by weight per 100 parts by weight of the component (a). The composition will not soften, sag or drip in molten drops even when subjected to the high-temperature conditions of a fire, and gives a tough residual product retaining the original shape when burned and ashed, effectively preventing the spread of fire and assuring outstanding smoketightness.

Abstract: This invention discloses an orthodontic unit disposition structure wherein a clinical area and a consultation area are provided in an adjacent relation with each other so as to carry out systematic and rational treatment and instruction from first to last whereby a patient can have his case initially diagnosed and then receive treatment and instruction, thus being enabled to undergo an effective operation.

Abstract: A vertical tabulation control for a high speed printer comprises a presettable memory, such as a random access memory (RAM), for storing vertical tabulation addresses, a counter for counting the number of line feed operations, a comparator for developing a continuous line feed termination command when the contents of the counter reach the preset vertical tabulation address, and a rechargeable battery means which is charged when the printer is activated through a power switch. The rechargeable battery supplies the presettable memory and the counter with a necessary voltage for maintaining their contents when the power supply through the power switch is terminated.