摘要:
A piezoelectric electro-acoustic transducer eliminates a negative influence caused by metal terminals upon the sound pressure and resonant frequency characteristics even when size and thickness reduction of the transducer are made. The transducer includes a piezoelectric diaphragm which includes a piezoelectric ceramic plate and a metal plate stored in a casing. The transducer also includes metal terminals in contact with the piezoelectric diaphragm and extending to the outside of the casing. The modulus of elasticity X of one metal terminal is specifically determined to be within a range defined by: ##EQU1## where E (N/m.sup.3) is the Young's modulus of one metal terminal in contact with a piezoelectric element, b (mm) is the width of part of the metal terminal extending from the inside of the casing to the outside thereof, h (mm) is the thickness of the metal terminal, and L (mm) is the length of the metal terminal.
摘要:
A pattern drawing apparatus is provided. This apparatus draws a pattern on an object by irradiating the object with an electron beam. A pattern data corresponding to the pattern to be drawn is stored in a memory. The pattern data is sent to a controller that controls irradiation of the electron beam to the object. Check is made whether the controller correctly controls the irradiation of the electron beam in accordance with the stored pattern data. Another memory stores the pattern data per a predetermined number of bits included in the pattern data. The bit data is sent to the controller that generates high and low voltages to control the irradiation of the electron beam. A counter counts the numbers of bits and high or low voltages. A comparator compares the counted numbers of bits and voltages. The comparison results are sent to an indicator that indicates an error when the counted numbers are different from each other. The counted numbers themselves may be indicated. Instead of the comparator, an exclusive-OR circuit may be provided. The bits of the pattern data are exclusive-ORed with the voltages expressed as bits. The output of the exclusive-OR circuit may be indicated as a bit map. Further, the bits of the pattern data and the voltages also may be indicated as bit maps.
摘要:
An airfoil blade for a fan impeller, includes one blade surface portion formed by extrusion molding. A plurality of ribs are integrally formed with the one blade surface portion to extend upwardlyf rom it in generally a vertical direction and having heights as will provide a curve line for the other curved blade surface portion when end faces of the ribs are connected to each other. A sheet material is applied onto the ribs along their end faces to provide the other curved blade surface portion so as to form a blade configuration of the airfoil blade having a leading edge and a trailing edge and including hollow portions in it.
摘要:
A lithium-manganese complex oxide represented by a formula Li[Mn2-X-YLiXMY]O4+&dgr; (wherein M is at least one element selected from the groups IIa, IIIb and VIII of the 3rd and 4th periods, and 0.02≦X≦0.10, 0.05≦Y≦0.30 and −0.2≦&dgr;
摘要:
There is provided a co-condensation product obtainable by subjecting a p-alkylphenol to reaction with formaldehyde in the presence of an alkali catalyst to prepare a resol type condensate, and subjecting the resulting resol type condensate to reaction with a m-substituted phenol such as resorcin in the presence of an acid catalyst, wherein the content of the m-substituted phenol is not higher than 4% by weight, and the content of a component having a molecular weight not higher than 1,000 excluding both the p-alkylphenol and the m-substituted phenolis at least 25% by weight based on the total weight of the co-condensation product. This co-condensation product is low in fuming and in hygroscopic properties, exhibits excellent adhesiveness in vulcanizing adhesion between rubber and a reinforcing material, and further provides a vulcanized rubber article of high hardness.
摘要:
A rubber composition comprising the following components:(A) a rubber component comprising at least 50% by weight of a styrene/butadiene copolymer rubber;(B) an azodicarboxylic ester compound represented by the formula ##STR1## wherein X is an alkyl of 3 to 8 carbon atoms, an unsubstituted or substituted phenyl, or an unsubstituted or substituted benzyl;(C) carbon black having a nitrogen absorption specific surface area of 100 to 250 m.sup.2 /g and a dibutyl phthalate absorption number of 110 to 170 ml/100 g;(D) sulfur; and(E) a benzothiazole vulcanization accelerator.This rubber composition shows a high loss factor (tan .delta.) in a low temperature range, and a low loss factor in a high temperature range which when applied to the production of automobile tires, achieves improved braking power on wet, snow covered or frozen road surfaces. Lowered rolling resistance during driving without loss in the strength characteristics of the composition are also exhibited.
摘要:
A bisphenol monoester represented by the formula (I): ##STR1## wherein R.sup.1 is hydrogen or alkyl, R.sup.2 and R.sup.3 are each alkyl, and R.sup.4 is alkyl, alkenyl or phenyl, is produced by continuous two step reactions in which an aldehyde R.sup.1 -CHO and 2,4-dialkylphenol are subjected to a condensation reaction in a C.sub.6 -C.sub.10 aliphatic or C.sub.6 -C.sub.12 aromatic hydrocarbon solvent, and then a resulting bisphenol compound dissolved in the solvent is subjected to an esterification with a carboxylic acid R.sup.4 --COOH or its derivative. Prior to the esterification, the organic layer containing the bisphenol compound is subjected to a dehydration treatment, thereby enabling the two steps to proceed continuously without isolating the intermediate bisphenol compound. A purification process for the bisphenol monoester of the formula (I) is also disclosed in which the monoester is purified from a mixed solvent comprising a C.sub.6 -C.sub.12 aromatic hydrocarbon solvent and a C.sub.1 -C.sub.8 alcohol or C.sub.2 -C.sub.3 aliphatic nitrile solvent.
摘要:
Chain structured corpuscular calcium carbonate is produced by a carbonation of calcium hydroxide suspended in water in the presence of a chelating agent and a water soluble metal salt.