Abstract: In producing a catalyst used for synthesis of an unsaturated aldehyde and an unsaturated carboxylic acid by a gas-phase catalytic oxidation, there is used a step of packing an additive-containing catalyst precursor of the catalyst into a tubular reactor, passing a gas through the tubular reactor, and elevating, in this state, the temperature of the additive-containing catalyst precursor so that a temperature of the gas at an outlet of the catalyst precursor layer becomes higher than a temperature of the gas at an inlet of the catalyst precursor layer. The step makes possible easy and highly reproducible production of a high-performance catalyst which is small in the reduction in catalytic performance caused by, for example, the thermal decomposition of the additive contained in the catalyst precursor.

Abstract: A molybdenum-based precipitate is prepared according to a process including the first step of forming a crude precipitate by pH adjustment to 6.5 or less in the presence of an alkali metal compound, and the second step of dissolving the crude precipitate in aqueous ammonia and forming a precipitate by pH adjustment to 6.5 or less. Then, the resulting molybdenum-based precipitate is washed with an acid aqueous solution having a pH of 6.5 or less and containing not less than 0.01 mole/L of ammonium root. Thus, a change in average particle diameter can be suppressed and good workability can be achieved, so that a molybdenum-based precipitate having a high purity and a desired average particle diameter can be obtained.

Abstract: The method of producing a catalyst for synthesis of an unsaturated aldehyde and unsaturated carboxylic acid of the present invention is characterized in that the method comprises a step of adding liquid to particles containing molybdenum, bismuth and iron and kneading the mixture, and extrusion-molding this kneaded substance, a step of preserving the molded article obtained by extrusion molding, and at least one step of drying and calcining the preserved molded article, and the contact time of particles containing molybdenum, bismuth and iron with liquid is 1 to 48 hours, and the preserving time of the molded article is 50% or more of the contact time of particles containing molybdenum, bismuth and iron with liquid. According to the production method of the present invention, catalytic activity can be easily controlled, and a catalyst having high activity and high selectivity is obtained.

Abstract: The present invention relates to the effective utilization of a used catalyst containing at least molybdenum, an A element (at least one element selected from the group consisting of phosphorus and arsenic) and an X element (at least one element selected from the group consisting of potassium, rubidium and cesium), and provides a process for producing a catalyst, which comprises dispersing said used catalyst in water, adding thereto an alkali metal compound and/or ammonia solution, adjusting the resulting mixture to pH 6.5 or less to generate a precipitate containing at least molybdenum and the A element, and using the precipitate as a material for catalyst-constituting elements.

Abstract: The present invention provides novel extrusion-molded catalysts which is suitably usable in the synthesis of an unsaturated aldehyde and an unsaturated carboxylic acid by vapor-phase catalytic oxidation, which are prepared by molding-molding catalyst particles (or powders) comprising at least molybdenum, bismuth and iron as metallic elements participating in its catalytic action on this reaction, and which exhibit high catalytic activity and high selectivity for the unsaturated aldehyde and unsaturated carboxylic acid being desired products. When previously formed catalyst particles are subjected to extrusion molding, the catalyst particles are kneaded, for example, with a &bgr;-1,3-glucan and a liquid. Then, the kneaded material is subjected to an extrusion molding step in which a ceramic material is used for at least a part of the catalyst flow path. Thereafter, the extrusion-molded material is dried, calcined and otherwise treated to obtain a final extrusion-molded catalyst.

Abstract: In producing a catalyst used for synthesis of an unsaturated aldehyde and an unsaturated carboxylic acid by a gas-phase catalytic oxidation, there is used a step of packing an additive-containing catalyst precursor of the catalyst into a tubular reactor, passing a gas through the tubular reactor, and elevating, in this state, the temperature of the additive-containing catalyst precursor so that a temperature of the gas at an outlet of the catalyst precursor layer becomes higher than a temperature of the gas at an inlet of the catalyst precursor layer. The step makes possible easy and highly reproducible production of a high-performance catalyst which is small in the reduction in catalytic performance caused by, for example, the thermal decomposition of the additive contained in the catalyst precursor.

Abstract: A molybdenum-based precipitate is prepared according to a process including the first step of forming a crude precipitate by pH adjustment to 6.5 or less in the presence of an alkali metal compound, and the second step of dissolving the crude precipitate in aqueous ammonia and forming a precipitate by pH adjustment to 6.5 or less. Then, the resulting molybdenum-based precipitate is washed with an acid aqueous solution having a pH of 6.5 or less and containing not less than 0.01 mole/L of ammonium root. Thus, a change in average particle diameter can be suppressed and good workability can be achieved, so that a molybdenum-based precipitate having a high purity and a desired average particle diameter can be obtained.

Abstract: A method for packing of catalyst, which comprises mixing, into a shaped catalyst containing at least molybdenum and iron, used in the gas-phase catalytic oxidation of propylene, isobutylene, tert-butyl alcohol or methyl tert-butyl ether with molecular oxygen to synthesize an unsaturated aldehyde and an unsaturated carboxylic acid both corresponding to the raw material used, metal-made Raschig rings as auxiliary packing material having a bulk volume of 0.3-3.5 times that of the shaped catalyst and a packing density of 0.5-1.5 kg/l, and packing the resulting mixture into a fixed bed type reactor; and a process for producing an unsaturated aldehyde and an unsaturated carboxylic acid, which comprises subjecting propylene, isobutylene, tert-butyl alcohol or methyl tert-butyl ether to gas-phase catalytic oxidation using molecular oxygen, in a fixed bed type reactor wherein a catalyst is packed by the above method.

Abstract: An error correcting decoder includes a flag memory (20) which stores a flag indicative of a success of an error correction for a bit. When a column direction error correction is to be performed, if a flag for a bit indicates a success, no error correction is performed for the bit. That is, an output of a majority logic circuit (78) is forcedly made invalid. In performing the column direction error correction, if the number of success packets in a first-time row direction error correction is smaller than a predetermined value and if the number of bits corrected by the column direction error correction becomes equal to or larger than a predetermined number, it is deemed as that the column direction error correction is unsuccessful.

Abstract: A frame-synchronous reproducing circuit (10) includes a BIC status register (20) of six stages, and a BIC status signal (c) from each stage of the register is applied to a BIC pattern determination circuit (24) in which the BIC status signal (c) and a BIC changing pattern being stored in advance are compared with each other. If the both are coincident with each other, the BIC pattern determination circuit (24) applies a high-level signal to a JK flip-flop (26) via an OR circuit (48), whereby a high-level signal representing that frame synchronization has been settled is outputted from the JK flip-flop (26).

Abstract: In an error correction circuit, when a data loss is detected, substitute data comprising all bits of "1" or "0" are generated during a data loss period and substituted for the lost data for the data loss period. Thereafter, the whole data containing the substitute data are decoded in a predetermined error correction system to generate corrected data.

Abstract: There is provided a process for efficient production of a solid catalyst usable for synthesis of methacrylic acid from methacrolein which comprises adding a lower alcohol or acetone to a dried product obtained from a mixed solution or aqueous slurry containing at least Mo, P and V as catalyst components and shaping the mixture by extrusion molding.

Abstract: A write once type information recording medium having a recording format that includes sectors. Each Sector includes x pieces of p-bit frames. Each frame contains an f-bit synchronization signal region and a d-bit data region. Each bit of at least one x-bit packet in which a v-bit error correction code has been added to u-bit data, is distributed to each one of the data regions of the x pieces of frames. This makes it possible for the write once type information recording medium to have an increased data storage efficiency and an effective error correction capability for a burst error.

Abstract: Method and apparatus for transmitting an information signal generate a plurality of block signals on the basis of the information signal, generate a plurality of parity block signals on the basis of the plural data block signals, generate a frame signal containing the plural data block signals and the parity block signals, and send out the frame signal. Each of the data block signals includes a first block synchronizing signal indicating the start of the data block signal, a data signal containing the information signal and a first parity signal derived by encoding the data signal. Each of the parity block signals incudes a second block synchronizing signal indicating the start of the parity block signal, a second parity signal and a third parity signal. Bit signals located at same bit positions in the respective second parity signals are derived by encoding bit signals located at the same positions in the respective data signals.

Abstract: When a catalyst for producing methacrylic acid is prepared by shaping a catalyst component represented by the general formula P.sub.a Mo.sub.b V.sub.c X.sub.d Y.sub.e Z.sub.f O.sub.g wherein P, Mo, V, X, Y, Z, a, b, c, d, e, f and g are as defined in the specification, a catalyst capable of giving methacrylic acid in high yield is provided by adding one or more organic high-molecular weight compounds with an average particle size of 0.01-10 .mu.m, and carrying out heat treatment before use as a catalyst.

Abstract: A method of preparing a catalyst used for producing methacrylic acids through gas phase catalytic oxidation of methacrolein with molecular oxygen. The catalyst is represented by the formula:P.sub.a Mo.sub.b V.sub.c Ge.sub.d X.sub.e Y.sub.f Z.sub.g O.sub.hwherein P, Mo, V, Ge and O represent phosphorous, molybdenum, vanadium, germanium and oxygen, respectively; X represents at least one element selected from the group consisting of arsenic, antimony, bismuth, zirconium, tellurium, silver and boron; Y represents at lest one element selected from the group consisting of iron, copper, zinc, chromium, magnesium, tantalum, manganese, barium, gallium, cerium and lanthanum; Z represents at least one element selected from the group consisting of potassium, rubidium, cesium and thallium, and a, b, c, d, e, f, g and h represent the atomic ratios of the respective elements, and when b=12, then a=0.5-3, c=0.01-3, d=0.01-3, e=0-3, f=0-3, g=0.

Abstract: A digital signal transmission using OFDM modulation scheme in which the valid transmission data can be reproduced without requiring a recovery of the carriers at a receiver side. On a transmitter side, the transmission data sequence in which predetermined reference data for each carrier are placed among valid transmission data is modulated according to an orthogonal frequency division multiplexing (OFDM) modulation scheme using a plurality of carriers and obtained OFDM transmission signals are transmitted. On a receiver side, the received OFDM transmission signals are demodulated to obtain received data sequence containing valid received data and received reference data, and the valid transmission data are estimated from the received data sequence according to the valid received data, the received reference data, and the predetermined reference data for each carrier.

Abstract: A novel adsorber module for whole blood treatment is disclosed, which comprises a casing provided with a blood inlet and a blood outlet and a bundle of a plurality of porous hollow fibers disposed in the casing and disposed between and fluid-tightly connected at end portions thereof to the blood inlet and the blood outlet, wherein each porous hollow fiber comprises a membranous porous resin matrix having pores which open at least at the inner wall of the hollow fiber and a plurality of ligands linked to the overall surface, including the walls of open pores, of the porous resin matrix. The adsorber module can easily be constructed into an adsorber apparatus which can be practically employed for treatment of whole blood. With this apparatus, whole blood can be effectively, efficiently treated without the danger of blood coagulation and hollow clogging, whereby the malignant components of the whole blood can be effectively removed by adsorption on the ligands.

Abstract: A process for preparing a catalyst used for production of methacrolein and methacrylic acid by vapor phase oxidation of isobutylene or tertiary butanol includes adding an organic high-molecular weight compound having an average particle size of 0.01 .mu.m to 10 .mu.m, especially polymethyl methacrylate and/or polystyrene, to a MoBiFeCoNi-based catalyst, then molding the mixture and heat treating the molded product.

Abstract: In a process for producing a catalyst having a composition represented by the following formula usable to produce methacrylic acid by the gas-phase catalytic oxidation of methacrolein with molecular oxygen,P.sub.a Mo.sub.b Cu.sub.c V.sub.d X.sub.e Y.sub.f Z.sub.g O.sub.hwherein P, Mo, Cu, V and O are phosphorus, molybdenum, copper, vanadium and oxygen, respectively, X is at least one element selected from the group consisting of arsenic, antimony, bismuth, germanium, zirconium, tellurium and silver, Y is at least one element selected from the group consisting of iron, zinc, chromium, magnesium, tantalum, manganese, barium, boron, gallium, cerium and lanthanum, Z is at least one element selected from the group consisting of potassium, rubidium, cesium and thallium, a, b, c, d, e, f, g and h are an atomic ratio of each element, and when b is 12, a is 0.5 to 3, c is 0.01 to 2, d is 0.01 to 3, e is 0.01 to 3, f is 0 to 3, g is 0.