Abstract: A chain olefin-cyclic olefin copolymer is irradiated with an electron beam for crosslinking to prepare a crosslinked product of a cyclic olefinic polymer. The cyclic olefin contains a bicyclic olefin. The proportion of the cyclic olefin in the total amount of the chain olefin and the cyclic olefin is more than 15% by mol and not more than 40% by mol. The chain olefin-cyclic olefin copolymer has a glass transition temperature of 20 to 80° C. or has a degree of crystallinity of not more than 1%. The crosslinked product may have a haze of not more than 2%. The crosslinked product of the present invention has a low haze and a high transparency and combines heat resistance and flexibility.

Abstract: A process for producing a glucan derivative modified with a cyclic ester with a highly suppressed homopolymerization of a cyclic ester is provided. In a production process for a modified glucan derivative, by allowing a glucan derivative having a hydroxyl group to react with a cyclic ester in a solvent in the presence of a ring-opening polymerization catalyst to give a modified glucan derivative in which the cyclic ester is graft-polymerized to the glucan derivative, (1) the ring-opening polymerization catalyst is a metal complex which by itself does not initiate the polymerization of the cyclic ester; and (2) the solvent comprises a nonaromatic hydrocarbon solvent having a solubility in water of not more than 10% by weight at 20° C.

Abstract: Disclosed is a method for producing a cyclic ester-modified glucan derivative wherein generation of homopolymers of the cyclic ester can be highly suppressed. Specifically disclosed is a method for producing a modified glucan derivative to which a cyclic ester is graft-polymerized, wherein a glucan derivative having a hydroxyl group and a cyclic ester are reacted in a solvent in the presence of a ring-opening polymerization catalyst. In this method, (1) the ring-opening polymerization catalyst is composed of a metal complex which does not initiate polymerization of the cyclic ester by itself; (2) the solvent is composed of an aromatic hydrocarbon solvent having a solubility in water at 20° C. of not more than 10% by weight; and (3) the ratio of the solvent is set at not less than 60 parts by weight per 100 parts by weight of the glucan derivative having a hydroxyl group.

Abstract: A glucan derivative (e.g., a cellulose acylate derivative) which is useful for a thermoplastic resin, is inhibited in hygroscopicity at a high level and is excellent in compatibility with a plasticizer or solubility in a solvent is provided. In the glucan derivative which comprises an acyl group and a graft chain formed from at least one graft component selected from a lactone and a hydroxycarboxylic acid, each bonding to a glucose unit of a glucan (e.g., a cellulose) constituting the glucan derivative, a hydroxyl group in the graft chain is protected with a protecting group. The graft chain may be formed from a C4-16lactone. The hydroxyl group in the graft chain may be protected with an acyl group (e.g., a C2-8alkylcarbonyl group such as acetyl group). The degree of substitution of the acyl group may be from 1 to 2.99, and the degree of substitution of the graft chain may be from 0.01 to 2.

Abstract: The rubber-containing styrenic resin of the present invention comprises a styrenic resin matrix and a rubber component dispersed in particles. In the resin, the graft ratio of a styrenic monomer relative to the rubber component is not less than 1, the particle size of the dispersed rubber component is 0.

Abstract: The rubber-containing styrenic resin of the present invention comprises a styrenic resin matrix and a rubber component dispersed in particles. In the resin, the graft ratio of a styrenic monomer relative to the rubber component is not less than 1, the particle size of the dispersed rubber component is 0.1 to 3 &mgr;m, and the following equation (1) is satisfied: Mn=aT+b  (1) wherein Mn is the number average molecular weight of the matrix resin; T is the conversion of the styrenic monomer; a is a constant greater than 0; and b is a constant of 0 or greater. The rubber component may be a butadiene-series rubber. The particle-size distribution of the dispersed rubber component may have, for example, two peaks.

Abstract: A plasma generating electrode device including a substrate 31 made of a dense ceramic, and an electrode 55 buried in said substrate 31, wherein said electrode 55 is isolated from a setting face of said substrate 31, and plasma is generated over said substrate. It is preferable that the minimum thickness of an electromagnetic wave permeation layer 37 is not less than 0.1 mm, the average thickness of the electromagnetic wave permeation layer is not less than 0.5 mm, the electrode 55 is a planar electrode made of a metal bulk, and the electrode is a monolithic sinter free from a joint face. This structure can be applied to an electric dust collector, an electromagnetic shield device or an electrostatic chuck. These can be preferably installed inside a semiconductor production unit using a halogen-based corrosive gas.

Abstract: A plasma generating electrode device including a substrate 31 made of a dense ceramic, and an electrode 55 buried in said substrate 31, wherein said electrode 55 is isolated from a setting face of said substrate 31, and plasma is generated over said substrate. It is preferable that the minimum thickness of an electromagnetic wave permeation layer 37 is not less than 0.1 mm, the average thickness of the electromagnetic wave permeation layer is not less than 0.5 mm, the electrode 55 is a planar electrode made of a metal bulk, and the electrode is a monolithic sinter free from a joint face. This structure can be applied to an electric dust collector, an electromagnetic shield device or an electrostatic chuck. These can be preferably installed inside a semiconductor production unit using a halogen-based corrosive gas.

Abstract: A plasma generating electrode device including a substrate 31 made of a dense ceramic, and an electrode 55 buried in said substrate 31, wherein said electrode 55 is isolated from a setting face of said substrate 31, and plasma is generated over said substrate. It is preferable that the minimum thickness of an electromagnetic wave permeation layer 37 is not less than 0.1 mm, the average thickness of the electromagnetic wave permeation layer is not less than 0.5 mm, the electrode 55 is a planar electrode made of a metal bulk, and the electrode is a monolithic sinter free from a joint face. This structure can be applied to an electric dust collector, an electromagnetic shield device or an electrostatic chuck. These can be preferably installed inside a semiconductor production unit using a halogen-based corrosive gas.

Abstract: An aluminum nitride sintered body is provided comprising metal elements contained in an amount of not more than 100 ppm for each metal element except for aluminum and assuming black color of a lightness of not more than N 4 according to the definition of JIS Z 8721. The aluminum nitride sintered body has preferably a relative density of at least 99.3% and crystal grains constituting the sintered body have an average particle diameter of at least 0.6 .mu.m but not more than 4.0 .mu.m. A powder of aluminum nitride obtained by reduction nitriding method is sintered at a temperature of at least 1,800.degree. C. under a pressure of at least 120 kg/cm.sup.2. Sintering temperature is preferably not more than 2,000.degree. C. and the sintering is preferably effected for at least 2 hrs but not more than 5 hrs.

Abstract: A ceramic heater includes a substrate made of aluminum nitride, a resistive heating element buried in the substrate and made of a metal having a high melting point, and terminals electrically connected to the resistive heating element and buried in said substrate. The terminals are made of a metal having a high melting point and a coefficient of thermal expansion not smaller than that of the substrate. The metal of the resistive heating element has a coefficient of thermal expansion not smaller than that of the substrate. The coefficient of thermal expansion of each of the terminals and the resistive heating element is in a range from 5.0.times.10.sup.-6 /.degree.C. to 8.3.times.10.sup.-6 /.degree.C.

Abstract: A ceramic heater composed of a ceramic substrate and a resistant heating element embedded within the ceramic substrate along a predetermined planar pattern is obtained by holding a convolution of a spiral-coiled high melting metallic filament in the above predetermined planar pattern and heat-treating the convolution at a temperature not higher than a primary recrystallization commencement temperature of the high melting metal under a non-oxidative atmosphere to provide the resistant heating element, embedding the resulting resistant heating element within a ceramic shaped body, and then, sintering the ceramic shaped body.

Abstract: Ceramic articles such as ceramic heaters, ceramic static chucks or the like include a substrate 1, a functional member such as a resistance heating element 2 or the like embedded in the substrate 1, a terminal 12 and a conductive wire 5A arranged therebetween. The conductive wire 5A is connected and fixed to the terminal 12, and a connection portion C between the conductive wire 5A and the terminal 12 is continued thereto. Alternatively, a post portion formed on the terminal 12 is extended in a direction crossing to a thickness direction of a plate-like substrate 1, and an end portion of the resistance heating element 2 is wound around the post portion. Alternatively, an end portion of the resistance heating element 2 is connected to the terminal 3 at a center portion in a thickness direction of the plate-like substrate 1.

Abstract: An excellent corrosion resistant member of a ceramic heater for semiconductor production apparatuses to be exposed to a halogen series corrosive gas is provided. The corrosion resistant member uses one of an aluminum nitride and alumina sintered body as a substrate. A ceramic heater using the corrosion resistive member is also disclosed as well as a semiconductor heating device using the ceramic heater.

Abstract: A wafer heating apparatus can be obtained which prevents formation of a local gap caused by deflection or distortion, and the like, of a wafer at the time of heating the wafer so as to improve production yield of the heat treatment of the wafers. The apparatus includes a ceramic substrate, a heat generating resistive element embedded in the ceramic substrate, a film electrode formed on a front surface of the ceramic substrate, and a ceramic dielectric layer formed on the front surface of the ceramic substrate to coat the film electrode. A direct current power source is provided to generate Coulomb's force between the wafer and the film electrode via the dielectric layer to attract the wafer to a wafer-attracting surface of the dielectric layer, while heating the wafer attracted to the wafer-attracting surface by energizing the heat generating element through application of an electric current therethrough. A method of producing the wafer heating apparatus is also disclosed.

Abstract: A voltage non-linear type sintered resistor is disclosed, which is produced by reacting, under heating, a mixture consisting essentially of zinc oxide as a main component, and an additive exhibiting voltage non-linearity and silicon oxide as auxiliary components. The silicon oxide is contained in an amount of 0.3 to 4.0 mol % with respect to the sintered resistor when calculated as SiO.sub.2, and the average particle diameter of crystalline grains of the zinc oxide constituting the sintered body is not more than 6 .mu.m.

Abstract: In case of manufacturing a voltage non-linear resistor, a sintering process is divided into two completely separate steps, i.e. primary and secondary sinterings. The primary sintering is carried out under a reduced pressure and the second sintering is conducted under an atmospheric pressure with a sufficient amount of oxygen. The primary sintering is effects such that the relative density and open porosity of the primarily sintered body are 85% or more and 1% or less, respectively. The secondary sintering removes to a large extent, voids existing in the body and, oxidation of the body is sufficiently effected. Therefore, the finally sintered body has a high density, a large surge withstanding capability, and a high non-linearity index.

Abstract: A voltage non-linear resistor having lightning discharge current withstanding capability, switching surge current withstanding capability, and voltage non-linear index .alpha., including a resistor element body consisting essentially of zinc oxide, and a side highly resistive layer composed of a zinc silicate phase consisting essentially of Zn.sub.2 SiO.sub.4 and a spinel phase consisting essentially of Zn.sub.7 Sb.sub.2 O.sub.12 arranged on a side surface of the resistor element body, can be attained, having a porosity of the resistor element body of 2% or less, zinc silicate particles existing continuously in the side highly resistive layer, and a porosity of 10% or less in a region of the side highly resistive layer within 30 .mu.m or less from the resistor element body. A method of producing the voltage non-linear resistor is also provided.