Abstract: A piezoelectric electro-acoustic transducer has a substantially decreased resonant frequency without having to modify the size of a piezoelectric diaphragm or the shape of casing members used therein. The piezoelectric electro-acoustic transducer has a piezoelectric diaphragm including a metal plate and a piezoelectric ceramic disc disposed on one surface of the metal plate, wherein the piezoelectric diaphragm is to be supported at its periphery. A plurality of projections are specifically provided for stress transmission suppression at the periphery of the piezoelectric diaphragm in order to suppress or eliminate occurrence of circumferential transmission of a stress at the periphery during activation of the transducer.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An ITO sintered body according to the present invention has a density thereof of between 90 and 100% and a sintering particle size of between 1 and 20 .mu.m. A proportion of (In.sub.0.6 Sn.sub.0.4).sub.2 O.sub.3 in the ITO sintered body is 10% or below. Such an ITO sintered body is manufactured by mixing an indium oxide powder, whose BET surface area is between 15 and 30 m.sup.2 /g, a BET size/a crystallite size is 2 or below, and an average primary particle size is between 0.03 and 0.1 .mu.m, with tin oxide whose BET surface area is 3 m.sup.2 /g or below, and then by sintering the mixture.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A spherical micro-porous silica gel, which is characterized by having a mean diameter of 3-20 .mu.m, a bulk density of 0.28-0.41 g/cm.sup.3, a pore size of 18,000-100,000 and a specific surface area of 1,000-1,400 m.sup.2 /g and a production process therefor is characterized by employing (a) an aqueous solution containing SiO.sub.2 in which the primary particle diameter is not larger than 6 nm and the molar ratio of SiO.sub.2 to Na.sub.2 O is not larger than 5.5, (b) either stearic acid or a mixture of stearic acid and a non-ionic surface active agent of which HLB ranges from 3.5 to 6.0 as an emulsifier and (c) an organic acid as a gelling agent.

Abstract: An output voltage of an AC generator is produced through a full-wave rectifier and converted into a digital signal by an A/D converter. This digital signal is compared with a reference signal, and in accordance with the difference therebetween, the firing angle of a thyristor is controlled to regulate the field current. Synchronous point detectors detect a synchronous point of the output voltage of the AC generator. A microprocessor computes a firing angle of the thyristor in accordance with the difference between the digital signal and the reference signal and produces a signal representing the computed firing angle upon detection of the synchronous point. The thyristor is fired at the firing angle computed by the microprocessor.

Abstract: 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.