Takasago International Corporation

Takasago Koryo Kogyo Kabushiki Kaisha (takasago International

Fuji Photo Film Company, Limited

Yugengaisya Cepstrum

Akio Yamaguchi

Yoji Hori

Toshimitsu Hagiwara

Hitoshi Kondo

Susumu Akutagawa

Mamoru Yamada

Shigeru Mitsuhashi

Yoko Takahashi

Hideyuki Hongo

Takashi Imai

Shinya Yamada

Haruki Tsuruta

Yukiharu Iwaya

Yoshiharu Gonda

Tetsuharu Okazaki

Hiroko Kudo

Takao Nishishita

Shinji Endoh

Hiroshi Sugiyama

Tohru Kobayashi

Mitsunobu Usui

Hiroko Konuma

Minzo Sakaguchi

Motoki Suzuki

A howling canceller which suppresses occurrence of howling even when an open loop gain exceeds '1' in the whole reproduction band. In the howling canceller, an adaptive filter () operates a digital received voice signal with a tap coefficient to generate a pseudo echo; a subtractor () subtracts the pseudo echo from a digital transmitted voice signal to generate a residual signal; and an amplitude limiting circuit () limits the absolute value of the amplitude of the digital received voice signal to be equal to or smaller than a predetermined threshold which ensures that all of a D/A converter (), a power amplifier (), a speaker (), a microphone (), a microphone amplifier (), and an A/D converter () operate in a linear operation area, and outputs the amplitude-limited digital received voice signal to the D/A converter () and the adaptive filter ().

Howling canceller

An apparatus that improves the appearance of a tape being wound on a tape reel includes a tissue which is positioned in parallel to an inner surface of a flange of the tape reel and pushes the tape edge against the inner surface. In this apparatus, the reel-up of the tape is performed while moving the tissue in the same direction as the reel-up direction of the tape or performed without moving the tissue.

Tape pack appearance control apparatus

A novel phosphine compound usable as a catalyst in various asymmetric synthetic reactions is disclosed. The compound is a 2,2'-bis(diarylphosphino)-6,6'-bis(trifluoromethyl)-1,1'-biphenyl of (1): ##STR1## where R is a phenyl group or a phenyl group substituted by lower alkyl group, lower alkoxy group, halogen atom, or lower haloalkyl group.

Method of preparation of

An optically active compound which itself generally exhibits no antiferroelectric liquid crystal phase, but which can be added to an antiferroelectric liquid crystal or composition thereof having a high threshold voltage to reduce the threshold voltage of the resulting composition. Also disclosed is an antiferroelectric liquid crystal composition containing the optically active compound, a process for reducing the threshold voltage of an antiferroelectric liquid crystal composition, a process for producing the optically active compound, and a process for producing an optically active carboxylic acid as an intermediate.

Optically active compound, antiferroelectric liquid crystal composition

An optically active block polyester copolymer formed of structural units represented by the following general formulas (I) and (II): ##STR1## wherein represents for an asymmetric carbon atom and m and n each represents a natural number in the range of from 300 to 5000 is obtained by subjecting an optically active butyrolactone and a species of lactone other than the optically active butyrolactone to sequential ringopening copolymerization in the presence of a catalyst. This optically active block polyester copolymer possesses a high molecular weight and a high melting point (not less than 130.degree. C.) and forms a biodegradable and hydrolyzable material of high strength capable of tolerating the impacts of actual use.

Optically active block polyester copolymer and method for production

The biodegradable composition comprises at least poly(beta-hydroxybutyric acid) or a biodegradable copolymer thereof and a stereospecifically regular block copolymer having the structure units of formula (I): ##STR1## where R1 is a hydrocarbon group having 1 to 14 carbon atoms, optionally including double bonds, oxygen atoms or both of them; and m and n are respectively an integer ranging from 300 to 5,000, or having the structure units of formula (II): ##STR2## where R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are either a hydrogen atom or a methyl group; and m and n are respectively an integer ranging from 300 to 5,000.

Biodegradable high molecular composition

Disclosed is a novel optically active compound which exhibits an antiferroelectric liquid crystal phase and has a low threshold voltage and a low viscosity, a novel optically active compound which doesn't exhibit an antiferroelectric liquid crystal phase but can be incorporated in an antiferroelectric liquid crystal having a high threshold voltage to reduce the threshold voltage thereof, an antiferroelectric liquid crystal composition containing the compound, and a process for the reduction of the threshold voltage of an antiferroelectric liquid crystal composition.

Optically active compound and antiferroelectric liquid crystal

The block copolymer of polyesters and polycarbonates comprises at least one of each of the constituting units of (I) and (II) having the general formulae: ##STR1## where the sign * indicates an asymmetric carbon atom; R.sub.1, R.sup.2, R.sup.3 and R.sup.4 are either a hydrogen atom or a methyl group; m and n are respective a natural numbers ranging from 300 to 5000: The block copolymer is obtained by successive ring-opening and copolymerization of optically active .beta.-butyrolactones and cyclic carbonates in the presence of a catalyst. The block polymer obtained has high molecular weight and high melting temperature, and can thus be used as a high strength material for practical use and which has bio-degradable and hydrolyzable nature.

Block copolymer of polyesters and polycarbonates and process for

A biodegradable, optically active copolymer is disclosed. The copolymer is represented by general formula (I): ##STR1## wherein R.sup.1 represents a group selected from the group consisting of methyldimethylene, 1,2-dimethyldimethylene, 1,1-dimethyldimethylene, methyltrimethylene, tetramethylene, methyltetramethylene, pentamethylene, 1,4-dimethyl-2-oxo-3-oxytetramethylene, 2-oxo-3-oxytetramethylene, and 2-methyl-3-oxypentamethylene, and m and n each represents a natural number of from 10 to 15,000. According to the present invention, useful polymers which are a new type of functional materials characterized as having optical activity, biodegradability (enzymatic degradability), and hydrolyzability can be easily produced in an industrially advantageous manner by the ring-opening copolymerization of optically active .beta.-butyrolactone with various lactones.

Biodegradable optically active copolymer and process for producing the

A biodegradable optically active copolymer is disclosed, which is represented by the general formula (I): ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 each represents a hydrogen atom or a methyl group; m and n each represents a natural number wherein the sum thereof gives 10 to 5,000; and C* represents an asymmetric carbon atom, and a process for producing the copolymer by ring-opening copolymerization of optically active .beta.-butyrolactone with a cyclic carbonate in the presence of catalyst. The biodegradable optically active copolymer of the present invention provides excellent biodegradability (enzyme degradability) and hydrolyzability.

Biodegradable optically active copolymers and processes for producing

A process for producing poly(3-hydroxybutyric acid) comprising ring-opening polymerization of .beta.-butyrolactone is disclosed, wherein the ring-opening polymerization is carried out in the presence of at least one tin compound selected from the group consisting of a distannoxane derivative (e.g., 1-chloro-3-ethoxy-1,1,3,3-tetrabutyldistannoxane), a tin carboxylate compound (e.g., tin dioctanoate), and a di-lower alkyltin oxide (e.g., dibutyltin oxide). Poly(3-hydroxybutyric acid) can be produced in high yield at low cost through simple production steps. The resulting polymer has an increased molecular weight to a degree not heretofore attained.

Process for producing poly(3-hydroxybutyric acid)

An optically active oligomer obtained by polycondensation of an (R)-3-hydroxyalkanoic acid alkyl ester and at least one of a diol, a diamine and an amino alcohol and an optically active polymer obtained by copolymerization of said oligomer and a monomer selected from diisocyanic acid esters, dicarboxylic acid derivatives, and dichlorosilanes are disclosed. Novel functional polymers with biodegradability and hydrolyzability are produced with industrial advantage.

Biodegradable optically active polymers and intermediate oligomers

A fluorine-containing optically active compound represented by formula (I): ##STR1## wherein R.sub.1 represents a straight chain alkyl or alkoxy group having from 6 to 14 carbon atoms or a 4-alkylphenyl or 4-alkoxyphenyl group having from 8 to 12 carbon atoms; R.sub.2 represents a straight chain alkyl group having from 1 to 8 carbon atoms; C.sup.* represents an asymmetric carbon atoms; and X represents a hydrogen atom or a fluorine atom, provided that X represents a fluorine atom when R.sub.1 contains a phenyl group, and a liquid crystal composition containing the same are disclosed. The compound (I) has large spontaneous polarization and low viscosity to achieve a fast response time. In the N.sup.* phase of the compound (I), the helical pitch has small temperature dependence.

Fluorine-containing optically active compound and liquid crystal

An optically active 7-substituted-1,4-dioxepan-5-one derivative represented by the general formula (I): ##STR1## wherein R represents an alkyl group having from 1 to 5 carbon atoms; and * means an asymmetric carbon atom, is disclosed. An optically active polymer represented by formula (II): ##STR2## wherein R and * are as defined above; and n is an integer of 25 or more, obtained by ring opening polymerization of the optically active 7-substituted-1,4-dioxepan-5-one derivative represented by formula (I) is also disclosed. A process for producing the optically active polymer represented by formula (II) is further disclosed, comprising subjecting an optically active 7-substituted-1,4-dioxepan-5-one derivative represented by formula (I) to ring opening polymerization in the presence of at least one catalyst selected from the group consisting of (i) an organotin compound, (ii) an organoaluminum compound and water, and (iii) an organozinc compound and water.

Growing community of inventors

Kanagawa, Japan

Akio Yamaguchi