摘要:
A process for preparing a methacrylic acid ester by reacting methacrylic acid with a lower aliphatic alcohol in the liquid phase using a solid acid catalyst at a molar ratio of alcohol to methacrylic acid of 1.2-3.0 and a reaction temperature of 70.degree.-100.degree. C. is improved by(1) extracting the unreacted alcohol from the reaction mixture with an aqueous solvent at a temperature of 25.degree. to 70.degree. C.,(2) removing the low boiling substances from the extraction residual mixture by distillation, whereby an organic residue is generated containing methacrylic acid ester and unreacted methacrylic acid, and(3) separating the unreacted methacrylic acid and the methacrylic acid ester by distillation.
摘要:
A process for isolating methacrylic acid by solvent extraction from an aqueous methacrylic acid solution obtained from a gas phase catalytic oxidation reaction, characterized in that the aqueous methacrylic acid solution is previously first contacted with an extraction solvent, polymers precipitated out from the aqueous methacrylic acid solution are removed and the remainder is fed into an extraction column.
摘要:
A pre-array temporary placement area A2 and a post-return temporary placement area A3 are set along with a lower receiving area A1. Temporary placement positions TP for lower receiving pins 22 in the pre-array temporary placement area A2 and the post-return temporary placement area A3 are previously assigned in consideration of requirements for preventing occurrence of interference between the lower receiving pins 22, which would otherwise occur during transfer of the lower receiving pins 22, and in accordance with array positions AP of the lower receiving pins 22 in the lower receiving area A1. Further, a transfer sequence is set in accordance with array positions AP.
摘要:
There are provided a charged particle beam apparatus and a method of adjusting an axis of an aperture capable of adjusting a position of a center axis of the aperture easily and accurately in a short period of time.A charged particle beam apparatus 1 includes a charged particle source 9, an aperture 18, an object lens 12, observing means 32, an aperture driving portion 19, and a control portion 30. The control portion 30 includes spot pattern forming means 33 for forming a plurality of spot patterns on a surface N1 of a sample N by irradiating a charged particle beam I, analyzing means for calculating a position of a spot center of the spot pattern and a geometrical center position of a halo, and adjusting position determining means 35 for calculating an adjusting position based on a position of intersecting lines of connecting the positions of the spot centers of the respective spot patterns and the center position of the halo, in which a position of the aperture 18 is adjusted by moving the center axis of the aperture 18 to the adjusting position.
摘要:
An electronic parts mounting apparatus and an electronic parts mounting method for picking up a plurality of electronic parts simultaneously by a transfer head having a plurality of suction nozzles from a plurality of tape feeders and then mounting the electronic parts on a substrate are provided. Displacement amounts of parts stop positions in respective tape feeders are detected in advance and stored as stop position correction data, and then tape feeding mechanisms are controlled based on the stop position correction data upon picking up the parts by the transfer head to execute such a registration that causes the parts stop positions to coincide with parts suction positions of the suction nozzles in the transfer head.
摘要:
A liquid delivery nozzle to be used in gasoline stations comprising two pairs of light sensor in which the first pair arranged at the tip end of the nozzle is of reflection type and the second pair arranged a little higher up from said first pair is of usual contact type, for more relevantly coping with full tank delivery. The sensors are mounted in a casing which is to be mounted on the nozzle inner wall surface near the tip end. In order to prevent leads extending through said nozzle and a hose connected therewith for angular movement from being damaged due to such angular movement, a flexible sheet on which leads are printed or embedded, has a part wound to form several spiral turns. The sheet is arranged in the portion where angular movement occurs to cope with such movement by loosening or tightening of the spiral turns.
摘要:
Provided are an X-ray analyzer and a mapping method for an X-ray analysis which, in a inspection for a harmful substance contained in, for example, a material or a composite electronic component, enable determination as to whether a sample is normal or abnormal to be performed visually based on an image obtained by the X-ray mapping analysis. In the X-ray analyzer, an X-ray mapping image of a sample which is confirmed to be normal in advance is obtained as a reference mapping image. A mapping analysis is performed on a inspection sample. A difference from the reference mapping image is obtained for each pixel, to thereby display a difference mapping image. A region in which the amount of specific element is larger than a reference amount is displayed with high brightness, and hence an abnormal portion may be easily found.
摘要:
A cylinder containing gas has a valve and is connected to a delivery side through a filling pipe, a primary pipe, a first air-operated valve, a pressure reducing valve, a secondary pipe, and a second air-operated valve. Inert gas flows into the primary pipe through an air-operated valve. The primary pipe is connected to a vacuum generator through an air-operated valve and a pipe. Gas remaining in the primary pipe is purged as exhaust gas by automatically repeating leaving-pipe-in-pressurized-state purge for pressurizing the inside of the primary pipe by the inert gas and leaving the pipe in this state for 2 to 10 minutes and evacuating the pipe for 20 seconds. Gas remaining in the primary pipe is purged with high-efficiency, and the vacuum generator is stopped while the inside of the primary pipe is pressurized in the leaving-pipe-in-pressurized-state purge and the just-before-replacement purge.
摘要:
A resin composition which comprises 95 to 60 volume % of a resin mixture of 40 to 85% by weight of a copolymer between D-hydroxybutyrate and D-hydroxyvalerate containing 8 to 15 mol % of D-hydroxyvalerate-derived monomer unit and 60 to 15% by weight of poly-.epsilon.-caprolactone, and 5 to 40 volume % of an inorganic filler or fillers, a porous film produced from the resin composition and having a void volume of 10 to 70%, and a process for producing the porous film are disclosed. The film can be produced by melting the resin composition, forming it into a film, and stretching the film in at least one direction. The porous film can easily be degraded by microorganisms. Examples of the inorganic filler include barium sulfate, with the particle size being preferably 0.1 to 10.0 .mu.m.
摘要:
An apparatus for measuring the quantity of a liquid such as a fuel in a tank, which comprises liquid level measuring electrodes, comparing electrodes dipped always in the liquid to detect the capacitance inherent to the liquid, an LC oscillator for converting each capacitive value measured by the electrodes into a corresponding frequency signal, reference electrodes constituting a level feeder together with the oscillator to compensate for capacitive variation of the latter, and a microcomputer for calculating a liquid quantity in the tank based on the frequency signals and for displaying the calculated quantity.