Abstract: The invention provides an image information conversion apparatus and method by which picture quality deterioration caused by setting of an initial value can be prevented when code amount control in MPEG4 image coding is performed based on information extracted from MPEG2 image compression information. An initial reference quantization scale determination section determines an initial value for a reference quantization scale from predetermined MPEG2 image compression information, the number of macro blocks to be included in an MPEG4 bit stream, a code amount allocated to the first I picture of the MPEG2 image compression information stored in an information buffer, an average quantization scale and a target code amount for the first I-VOP of the MPEG4 bit stream calculated by an MPEG4 image information coding section, and then calculates an initial value for a virtual buffer occupation amount based on the determined initial value for the reference quantization scale.

Abstract: A technique is disclosed for reducing the bit rate of a bit stream coded into a compressed form according to the MPEG-2 standard, without causing significant degradation in image quality of a decoded image. An inverse DCT converter dequantizes a MPEG-2 bit stream and outputs resultant discrete cosine transform coefficients for each DCT block. A band limiter replaces the values of high-frequency components of the discrete cosine transform coefficients in the horizontal direction, with 0. A quantizer quantizes the discrete cosine transform coefficients using a quantization step value different from the original value.

Abstract: The invention provides an image information conversion apparatus and method by which picture quality deterioration caused by setting of an initial value can be prevented when code amount control in MPEG4 image coding is performed based on information extracted from MPEG2 image compression information. An initial reference quantization scale determination section determines an initial value for a reference quantization scale from predetermined MPEG2 image compression information, the number of macro blocks to be included in an MPEG4 bit stream, a code amount allocated to the first I picture of the MPEG2 image compression information stored in an information buffer, an average quantization scale and a target code amount for the first I-VOP of the MPEG4 bit stream calculated by an MPEG4 image information coding section, and then calculates an initial value for a virtual buffer occupation amount based on the determined initial value for the reference quantization scale.

Abstract: An efficient and safe method is proposed for the preparation of an oximesilane compound having a group of the general formula --O--N.dbd.CR.sup.2 R.sup.3, in which R.sup.2 and R.sup.3 are each a hydrogen atom or a monovalent hydrocarbon group, bonded to the silicon atom. The method consists of successive steps of which the first is for the reaction of a chlorosilane compound with ammonia and the second is for the reaction of the reaction mixture coming from the first step with an oxime compound to introduce the oxime groups as bonded to the silicon atom. Different from conventional methods in which formation of an explosive compound such as hydrochloride of an organic base or oxime compound is unavoidable, the inventive method does not involve formation of such an explosive by-product so that the desired oximesilane compound can be obtained without the danger of explosion.

Abstract: A novel and efficient method is disclosed for decreasing the content of residual alkoxy groups in an organopolysiloxane such as so-called MQ resins, usually and unavoidably, having a considerable amount of residual alkoxy groups bonded to the silicon atoms to be very detrimental against practical application of the organopolysiloxane. The method comprises admixing the alkoxy-containing organopolysiloxane with a strongly alkaline compound such as alkali metal hydroxides as a catalyst, an aprotic polar solvent such as N,N-dimethyl formamide, dimethyl sulfoxide and the like and water each in a specified amount and heating the mixture, for example, under reflux so that the alkoxy groups are rapidly hydrolyzed and can be removed in the form of an alcohol.

Abstract: A simple but very effective and reliable method is proposed for the decolorizing purification of a halogenated silane compound, e.g., methyl trichlorosilane, colored by containing a very small amount of heavy metal impurities such as iron. The method comprises: contacting the halogenated silane compound with a small amount of a cationic surface active agent which is solid and insoluble in the silane such as a quaternary ammonium salt, e.g., trimethyl octadecyl ammonium chloride, for 2 to 240 minutes; and then separating the silane compound from the cationic surface active agent.

Abstract: An improvement is proposed for minimizing coloration of an oximesilane synthesized by the reaction of a chlorosilane such as vinyl trichlorosilane and an oxime compound such as methyl ethyl ketone oxime in the presence of a nitrogen-containing basic compound as an acceptor of the hydrogen chloride followed by the removal of the precipitates of the hydrogen chloride salt of the base and distillation. The improvement comprises conducting the distillation of the filtrate after removal of the precipitates of salt is performed in the presence of a nitrogen-containing basic compound such as ammonia in the filtrate, for example, by blowing ammonia gas into the liquid under distillation. An already colored oximesilane product also can be decolorized by blowing ammonia gas thereinto.

Abstract: An efficient and economically advantageous method is proposed for the preparation of an organopolysiloxane comprising tetrafunctional siloxane units, i.e. Q units, and, typically, monofunctional siloxy units, i.e. M units, and useful as a reinforcing agent in silicone rubbers. The method comprises the steps of: mixing the reactants for providing the Q and M units, such as ethyl orthosilicate and trimethyl methoxy silane, in a desired molar ratio; and heating the mixture at a temperature higher by at least 10.degree. C. than the boiling point of the mixture under normal pressure in a closed vessel in the presence of water and a catalyst such as a sulfonic acid group-containing compound.

Abstract: An organopolysiloxane composed of tetrafuctional siloxane units SiO.sub.2 and monofunctional siloxane units R.sub.3 SiO.sub.0.5 can be prepared by reacting an alkyl orthosilicate, e.g., ethyl silicate, or a partial hydrolysis product thereof and an oligomeric organopolysiloxane containing the monofunctional siloxane units in the presence of a catalytic compound which is, different from conventional hydrogen chloride, selected from the group consisting of sulfonic acid group-containing compounds, e.g., sulfuric acid and p-toluene sulfonic acid, and phosphonitrile chloride. In particular, cation exchange resins of sulfonic acid type and fluorinated polysulfonic acid resins can be used as the catalyst in a continuous process in which the reaction mixture is passed through a bed of the catalyst continuously. The inventive method is advantageous over conventional methods because of the absence of the problems of heavy corrosion of the apparatuses and waste disposal due to the hydrogen chloride.