Abstract: A vacuum cleaner includes an optical dust sensor for detecting a quantity of dust which sensor is provided at a predetermined position of a suction path for sucking air by a suction force of the vacuum cleaner, whereby an output signal is supplied to a display device so that a display corresponding to the quantity of the sucked dust, which signal is output from the optical dust sensor and is varied in a stageless manner corresponding to the quantity of the dust.

Abstract: In a heat history initializing step, a heat treatment in performed in an atmosphere including at least one of hydrogen, helium, and argon while the temperature is increased in a range of 700.degree. C. to 1,000.degree. C. at a rate of 15.degree.-1,000.degree. C./min. In a controlled nuclei growing step, a heat treatment is performed in the above atmosphere while the temperature is kept constant in a range of 850.degree. C. to 980.degree. C. for 0.5-60 minutes.

Abstract: A silicon wafer is mirror-polished until obtaining surface roughness Ra of 0.70-1.00 nm, Rq of 0.80-1.10 nm, or Rt of 4.50-7.00 nm. The resulting wafer is heat-treated at a temperature not lower than 1,200.degree. C. for 30 minutes to 4 hours in a hydrogen gas atmosphere. According to another aspect, a silicon wafer is mirror-polished until obtaining surface roughness values Ra' of 0.08-0.70 nm, rms of 0.10-0.90 nm, and P-V of 0.80-5.80 nm in a square area of 90 .mu.m by 90 .mu.m, and surface roughness values Ra' of 0.13-0.40 nm, rms of 0.18-0.50 nm, and P-V of 1.30-2.50 nm in a square area of 500 nm by 500 nm. The resulting wafer is heat-treated at 1,100.degree.-1,300.degree. C. for 30 minutes to 4 hours in a hydrogen gas atmosphere.

Abstract: A vertical boat for holding a plurality of semiconductor wafers comprising two end members (2) positioned at the top and the bottom of the vertical boat, and a plurality of support members (3,4,5,6,104) vertically mounted on the end members (2) for supporting the wafers, wherein each support member (3,4,5,6,104) is formed by a plate-like member having a series of slits (9,10,7,8,108) formed thereon in such a manner that a plurality of support arms are defined by the slits (9,10,7,8,108) at a predetermined interval, each support arm having a support projection (11,12,13,14,112) formed at the end thereof, and wherein the inner portions (P) of the wafer (1) is to be supported by the support projections (11,12,13,14,112) whereas the periphery of the wafer (1) does not contact the arms of the support members (3,4,5,6,104).

Abstract: A timer operation management apparatus for managing the playback and recording of multiple video tape cassettes comprising cassette information storage capabilities for storing the presence/absence of cassette, the presence/absence of a safety lug, and the like; timer information capabilities capable of storing cassette designation information, start and stop time designations, record and play time designations, etc.; and wherein the cassette designation information includes both individual cassette designation information and all cassette designation information.

Abstract: Derivatives of ML-236B carboxylic acid, its salts and esters and corresponding lactone have a hydroxy group at the 3"-position and optionally also at the 6'-position. These derivatives may be prepared by the enzymatic hydroxylation of a corresponding ML-236B compound employing an enzyme produced by a microorganism of the genus Streptomyces or Amycolata, especially Streptomyces sp. SANK 62285, Streptomyces sp. SANK 62385, Streptomyces sp. SANK 62485, Streptomyces sp. SANK 62585, Amycolata autotrophica SANK 62781. Amycolata autotrophica subsp. canberrica SANK 62882 or Amycolata autotrophica subsp. amethystina SANK 62981. These derivatives have the ability to inhibit cholesterol biosynthesis.

Abstract: Derivatives of ML-236B carboxylic acid, its salts and esters and corresponding lactone have a hydroxy group at the 3"-position and optionally also at the 6'-position. These derivatives may be prepared by the enzymatic hydroxylation of a corresponding ML-236B compound employing an enzyme produced by a microorganism of the genus Streptomyces or Amycolata, especially Streptomyces sp. SANK 62285, Streptomyces sp. SANK 62385, Streptomyces sp. SANK 62485, Streptomyces sp. SANK 62585, Amycolata autotrophica SANK 62781, Amycolata autotrophica subsp. canberrica SANK 62882 or Amycolata autotrophica subsp. amethystina SANK 62981. These derivatives have the ability to inhibit cholesterol biosynthesis.

Abstract: A method of producing plastic pipe having air channels axially extending through the wall thereof, with at least one of the respective ends of the air channels being closed by an annular slotted channel-closure filled with a caulking material in its annular slot. The channel-closure is force-fitted on the pipe end, so that the caulking material is pressed into the air channels.