Abstract: A method and apparatus for controlling the level of molten metal in a mold for continuous casting by using a molten metal level control system incorporating a molten metal level controller in the control loop thereof, which comprises damping selectively the predetermined frequency of frequencies of periodical molten metal level fluctuations through a notch filter installed in the control loop. The control loop preferably includes the phase compensation calculation part for compensating the phase delay of the stopper opening position control signal for adjusting the amount of the molten metal to be fed to the mold. The control apparatus in the control loop comprises a molten metal level senser, an FFT analyzer, an automatic tuning device for dealing with the results of the FFT analysis, a molten metal level controller and a notch filter.

Abstract: A method of continuous casting of a steel employs a mold power having a viscosity of 0.5-1.5 poise at 1,300° C. and a solidification temperature of 1,190-1,270° C., in which the mass ratio of CaO to SiO2 is 1.2-1.9, and casting is carried out under the following conditions: casting speed is 2.5-10 m/minute; mold oscillation stroke is 4-15 mm; and specific cooling intensity in secondary cooling of a slab is 1.0-5.0 liter/kg-steel.

Abstract: Steel is continuously cast in a mold at a casting speed of 2.5 to 10 m/min while the mold is oscillated so as to satisfy the relationship 450≦(S×f/Vc)≦1000, wherein S is the stroke of mold oscillation in mm, f is the frequency of mold oscillation in cycles per minute, and Vc is the casting speed in m/min.

Abstract: A method of controlling the level of molten metal in a mold for continuous casting by using a molten metal level control system incorporating a molten metal level controller in the control loop thereof, which comprises damping selectively the predetermined frequency of frequencies of periodical molten metal level fluctuations through a notch filter installed in the control loop. The control loop preferably includes the phase compensation calculation part for compensating the phase delay of the stopper opening position control signal for adjusting the amount of the molten metal to be fed to the mold. The control apparatus in the control loop comprises a molten metal level senser, an FFT analyzer, an automatic tuning device for dealing with the results of the FFT analysis, a molten metal level controller and a notch filter.

Abstract: A continuous casting method and apparatus therefor wherein a reaction force/reduction controller selects a pivot reduction roll such that the thickness of the solidified shell of the cast slab having a liquid core is equal to the target thickness T.sub.ref, and calculates a difference between a thickness T.sub.in of the cast slab having a liquid core at the inlet of the reduction roll zone PRT and the target thickness T.sub.ref, i.e., .DELTA.T. The resulting value of .DELTA.T, i.e., a target reduction is provided to the reduction controllers 2 of the pivot reduction roll. The reaction force/reduction controller 1 assigns target reductions 1/3 .DELTA.T and 2/3 .DELTA.T to the two reduction rolls upstream of the pivot reduction roll. The reaction force/reduction controller 1 calculates a target pressure (P.sub.i +.alpha.) on the basis of the selected value for .alpha., and the resulting target pressure (P.sub.i +.alpha.

Abstract: In order to control a molten metal level within a mold of a system comprising a liquid core reduction device, while controlling a fluctuation of the molten metal level caused by a change of operational conditions, such as the withdrawal rate, reduction speed, etc., with improvement of the yield rate of product slabs, a method comprises the steps of: (i) estimating a disturbance to the molten metal level, which is caused by a change in operating conditions of a continuous casting machine before changing the operating conditions; (ii) determining an amount of correction of the control signal to eliminate the disturbance, and determining a delay time of the operation of the pouring means in responses to the control signal after correction; and (iii) applying a control signal containing the amount of correction in advance by a period of the delay time prior to the occurrence of a change in operating conditions.

Abstract: A fluorovinyl ether of the formula:R.sub.f --(OCF.sub.2 CF.sub.2 CF.sub.2).sub.n --OCF.dbd.CF.sub.2(I)wherein R.sub.f is a C.sub.1 -C.sub.5 perfluoroalkyl group, n is an integer of 1 to 4 provided that when n is 1 (one), R.sub.f is other than a trifluoromethyl group, a copolymer of which with an ethylenically unsaturated compound has a low glass transition temperature and improved low temperature properties.

Abstract: At least three video signals including at least one video signal which is given special effects are combined into a single video signal. Each of the three video signals contains a key signal and depth information. Two video signals closer to a viewpoint for images represented by the video signals are selected from the at least three video signals, per pixel, by comparing the depth information contained in the video signals per pixel to detect two pieces of depth information corresponding to two pixels closer to said viewpoint, and holding the two pixels corresponding to the detected two pieces of depth information based on the detected two pieces of depth information. Then, the selected video signals are weighted and mixed based on the key signals and depth information thereof per pixel.

Abstract: A fluorovinyl ether of the formula:R.sub.f --(OCF.sub.2 CF.sub.2 CF.sub.2).sub.n --OCF.dbd.CF.sub.2(I)wherein R.sub.f is a C.sub.1- -C.sub.5 perfluoroalkyl group, n is an integer of 1 to 4 provided that when n is 1 (one), R.sub.f is other than a trifluoromethyl group, a copolymer of which with an ethylenically unsaturated compound has a low glass transition temperature and improved low temperature properties.

Abstract: A novel fluorine-containing acrylic acid derivative of the invention is represented by the formula:(CH.sub.2 .dbd.CF--CO).sub.p --A (I)wherein A is a residue derived from an organic compound having at least two active hydrogen atoms derived by removing at least two active hydrogen atoms, and p is an integer corresponding to the valency of the residue A, which is easily cured.

Abstract: A novel fluorine-containing acrylic acid derivative of the invention is represented by the formula:(CH.sub.2 .dbd.CF--CO).sub.p --A (I)wherein A is a residue derived from an organic compound having at least two active hydrogen atoms derived by removing at least two active hydrogen atoms, and p is an integer corresponding to the valency of the residue A, which is easily cured.

Abstract: A fluorovinyl ether of the formula:XCH.sub.2 CF.sub.2 CF.sub.2 --(OCH.sub.2 CF.sub.2 CF.sub.2).sub.m --(OCFYCF.sub.2).sub.n --OCF.dbd.CF.sub.2 (I)wherein X is a hydrogen atom or a halogen atom (e.g. fluorine, chlorine, bromine and iodine); Y is a fluorine atom or a trifluoromethyl group; m is an integer of 0 to 5; and n is 0, 1 or 2, which can modify a polymer of at least one ethylenically unsaturated compound.

Abstract: A monomer which is hardly souble in water is effectively emulsion polymerized or copolymerized in the presence of a polymerization initiating source when the polymerization is carried out in the presence of a monovalent cation.

Abstract: A fluorine-containing non-crystalline copolymer comprising 10 to 90% by mole of repeating units derived from tetrafluoroethylene and 90 to 10% by mole of repeating units derived form a fluorovinyl ether of the formula:CH.sub.2 .dbd.CHOCH.sub.2 (CF.sub.2).sub.n X (I)wherein X is a halogen atom or a hydrogen atom and n is a number of 2 to 8, and a copolymer comprising repeating units derived from tetrafluoroethylene, the fluorovinyl ether (I) and a third monomer selected from the group consisting of vinylidene fluoride and ethylene in which the content of repeating units derived from the third monomer is from 1 to 80% by mole in case of vinylidene fluoride or from 10 to 60% by mole in case of ethylene, and the reminder consists of the repeating units derived form tetrafluoroethylene and the fluorovinyl ether (I) in a molar ratio of 1:9 to 9:1, which have good low temperature properties as well as resistance to heat, oil and chemicals.

Abstract: A novel fluorine-containing acrylic acid derivative of the invention is represented by the formula:(CH.sub.2 .dbd.CF--CO).sub.p--A (I)wherein A is a residue derived from an organic compound having at least two active hydrogen atoms derived by removing at least two active hydrogen atoms, and p is an integer corresponding to the valency of the residue A, which is easily cured.

Abstract: A cross-linkable coating composition comprising a fluorine-containing elastomeric copolymer which comprises (a) 50 to 95% by mole of repeating units derived from a fluoroolefin of the formula:CF.sub.2 .dbd.CXY (I)wherein X and Y are the same or different and a fluorine atom or a chlorine atom, (b) 50 to 5% by mole of repeating units derived from a perfluorovinyl ether of the formula:R.sub.f --[OCFZCF.sub.2 (CF.sub.2).sub.m ].sub.n --OCF.dbd.CF.sub.2 (II)wherein R.sub.f is a C.sub.1 -C.sub.6 perfluoroalkyl group, Z is a fluorine atom or a trifluoromethyl group, n is an integer of 0 to 5 and m is 0 to 1 provided that when m is 1 (one), X is not a trifluoromethyl group and a cross-linking agent for the copolymer, the copolymer and the cross-linking agent being dissolved or dispersed in a fluorosolvent is provided.

Abstract: An optical fiber comprising a core and a cladding, wherein the core is made of a polymer comprising units of methyl methacrylate, and the cladding is made of a copolymer comprising units of vinylidene fluoride and 0.5 to 10% by mole of units of hexafluoropropene, having good heat resistance and flexibility and is excellent in adhesivity between the core and the cladding.

Abstract: An elastomeric fluoropolymer comprising 12 to 50% by mole of repeating units derived from a perfluorovinyl ether of the formula:CF.sub.2 .dbd.CFO--(CF.sub.2 CFXO).sub.m --R.sub.f (I)wherein R.sub.f is a C.sub.1 -C.sub.6 perfluoroalkyl group, X is a fluorine atom or a trifluoromethyl group and m is an integer of 1 to 5, 50 to 88% by mole of repeating units derived from tetrafluoroethylene and 0.1 to 5% by mole of repeating units of hexafluoropropylene having improved strength and compression set.

Abstract: A copolymer comprising repeating units derived from tetrafluoroethylene, vinylidene fluoride and hexafluoropropylene in a molar ratio within an area defined on a tetrafluoroethylene, vinylidene fluoride and hexafluoropropylene ternary composition diagram by a hexagon with its first vertex A at 34.0% by weight of tetrafluoroethylene, 8.5% by weight of vinylidene fluoride and 57.5% by weight of hexafluoropropylene; its second vertex B at 26.5% by weight of tetrafluoroethylene, 14.5% by weight of vinylidene fluoride and 59.0% by weight of hexafluoropropylene; its third vertex C at 31.0% by weight of tetrafluoroethylene, 24.0% by weight of vinylidene fluoride and 45.0% by weight of hexafluoropropylene; its fourth vertex D at 49.0% by weight of tetrafluoroethylene, 26.5% by weight of vinylidene fluoride and 24.5% by weight of hexafluoropropylene; its fifth vertex E at 49.0% by weight of tetrafluoroethylene, 11.0% by weight of vinylidene fluoride and 40.

Abstract: An impregnated material comprising an organic or inorganic material selected from the group consisting of a woven fabric, a non-woven fabric and an open cell porous material which is impregnated with a copolymer which comprises 50 to 95% by mole of repeating units derived from tetrafluoroethylene and 5 to 50% by mole of repeating units derived from perfluoroalkyl vinyl ether of the formula:CF.sub.2 .dbd.CFOR.sub.f (I)wherein R.sub.f is a C.sub.1 -C.sub.6 perfluoroalkyl group or a group of the formula:--(CF.sub.2 CFXO).sub.n --R.sub.f (II)wherein R.sub.f is the same as defined above, X is a fluorine atom or a trifluoromethyl group and n is an integer of 1 to 10, which has good chemical, corrosion, solvent and oil resistance as well as water- and oil-repellence.