Abstract: In a Stirling cooling apparatus, a refrigerant is circulated within a refrigerant circulation circuit in such a way that the refrigerant receives cold, as latent heat, from a Stirling chiller and then releases the cold, by absorbing heat of vaporization, as it vaporizes in an evaporator, thereby cooling the inside of a refrigerator chamber. As the refrigerant, carbon dioxide, a natural refrigerant, can be suitably used.

Abstract: A silicon nitride porous body which is obtained by nitriding a molded body having metallic silicon as a main component and by performing a high temperature heating treatment at a temperature higher than the nitriding temperature, and which has a porous structure with an average pore diameter of 3 ?m or above, and contains at least one kind of element selected from the group consisting of the groups 2A, 3A, 3B inclusive of lanthanoid elements, and 4B. The silicon nitride porous body has a porous structure with a large average pore diameter, a test specimen cut out from the porous body exhibiting a high thermal conductivity and a small thermal expansion coefficient, and can be suitably used in a component for purifying gas and/or solution such as a ceramic filter.

Abstract: A halogen gas plasma-resistant member to be exposed to a halogen gas plasma, includes a main body of said member, and a corrosion-resistant film formed at least a surface of said main body, wherein a peeling resistance of the corrosive film to said main body is not less than 15 MPa.

Abstract: In a Stirling refrigerator, waste heat rejected from the heat rejecter of a Stirling refrigerating device is transferred by way of dew prevention heat pipes to heat the open side of the refrigerator. This makes it possible to prevent condensation of moisture on the open side of the refrigerator, where dew tends to collect as a door is opened or closed or in other situations, in an effective and energy-saving manner without using a heater, and thereby alleviate the load on the heat-rejecting heat exchanger.

Abstract: A Stirling cycle refrigerating system has a pair of reversed Stirling cycle engines 3a and 3b, each comprising a warm head 8a and 8b of which the temperature rises as the reversed Stirling cycle engine is driven, a cold head 7a and 7b of which the temperature falls as the reversed Stirling cycle engine is driven, and a piston and a displacer that vibrate inside a cylinder along the axis thereof with an identical period and with a predetermined phase difference maintained. Inside a machine chamber 15, the pair of reversed Stirling cycle engines 3a and 3b is arranged coaxially with the axes thereof aligned with each other and with the cold heads 7a and 7b thereof facing away from each other, and the pistons or displacers of the pair of reversed Stirling cycle engines 3a and 3b are driven to vibrate in phase with each other.

Abstract: A silicon nitride porous body (5) obtained by nitriding a molded body having metallic silicon (3) as a main component, the porous body having a porous structure with an average pore diameter of 3 &mgr;m or above, and wherein the total content of silicon and nitrogen is 95% or above and the nitridation ratio of silicon is 90% or above. The silicon nitride porous body has a porous structure with a large average pore diameter, with a test specimen cut out from the porous body exhibiting large thermal conductivity and a small thermal expansion coefficient, and can be suitably used in a component for purifying gas and/or solution such as a ceramic filter.

Abstract: A silicon nitride sintered material includes a polycrystal material having silicon nitride crystal grains and a grain boundary phase. The sintered material contains a Yb element in an amount of 2 to 30% by weight in terms of its oxide and an Al element in an amount of 1 to 20% by weight in terms of its oxide and has a thermal conductivity of 40 W/mK or less at room temperature, a resistivity of 1×105to 1×1012 &OHgr;·cm at room temperature, and a porosity of 0.5% or less.

Abstract: A silicon nitride porous body which is obtained by nitriding a molded body having metallic silicon as a main component and by performing a high temperature heating treatment at a temperature higher than the nitriding temperature, and which has a porous structure with an average pore diameter of 3 &mgr;m or above, and contains at least one kind of element selected from the group consisting of the groups 2A, 3A, 3B inclusive of lanthanoid elements, and 4B. The silicon nitride porous body has a porous structure with a large average pore diameter, a test specimen cut out from the porous body exhibiting a high thermal conductivity and a small thermal expansion coefficient, and can be suitably used in a component for purifying gas and/or solution such as a ceramic filter.

Abstract: A unique recording medium having identification information such as a serial number or ID number inherent in the recording media as information signals recorded thereon, which is prevented from being easily erased or rewritten, without inducing the complexity of an optical disc reproducing apparatus in its configuration and the intricacy of the reading-out operation is realized. Recognition information is recorded to a recording medium which has a recognition information recording area for recording the recognition information, and at least the recognition information recording area is capable of additionally having information recorded thereto. In recording digitized recognition information to the recognition information recording area, the “1” is modulated to a signal having a first frequency and the “0” is modulated to a signal having a second frequency, and the signals corresponding to their respective frequencies are written to the recognition information recording area.

Abstract: A material with a low volume resistivity at room temperature composed of an aluminum nitride sintered body is provided. The sintered body contains samarium in a converted content calculated as samarium oxide of not lower than 0.04 mole percent. The sintered body contains an aluminum nitride phase and a samarium-aluminum complex oxide phase. The samarium-aluminum complex oxide phase forms intergranular layers with a low resistivity along the intergranular phase between aluminum nitride grains.

Abstract: A silicon nitride sintered material includes a polycrystal material having silicon nitride crystal grains and a grain boundary phase. The sintered material contains a Yb element in an amount of 2 to 30% by weight in terms of its oxide and an Al element in an amount of 1 to 20% by weight in terms of its oxide and has a thermal conductivity of 40 W/mK or less at room temperature, a resistivity of 1×105 to 1×1012 &OHgr;·cm at room temperature, and a porosity of 0.5% or less.

Abstract: A silicon nitride sintered material includes a polycrystal material having silicon nitride crystal grains and a grain boundary phase. The sintered material contains a Yb element in an amount of 2 to 30% by weight in terms of its oxide and an Al element in an amount of 1 to 20% by weight in terms of its oxide and has a thermal conductivity of 40 W/mK or less at room temperature, a resistivity of 1×105 to 1×1012 &OHgr;·cm at room temperature, and a porosity of 0.5% or less.

Abstract: An aluminum nitride sintered body is provided. The aluminum nitride has a polycrystalline structure of aluminum nitride crystals having an average particle diameter in a range of 5 &mgr;m to 20 &mgr;m and cerium in a range of 0.01 wt % 1.0 wt %, when calculated as an oxide thereof. The aluminum nitride sintered body has a room temperature volume resistivity in a range of 1×108 &OHgr;·cm to 1×1012 &OHgr;·cm under the application of 500 V/mm, and a value of a in the I-V relational equation, I=kV&agr;, is in a range of 1.0 to 1.5, V being a voltage in a range of 100 V/mm to 1000 V/mm, I being a leak current when V is applied to said aluminum nitride body, k being a constant, and &agr; being a non-linear coefficient.

Abstract: A nitriding portion made of aluminum nitride as a main ingredient having a high concentration region in which an element mentioned below is existent at a high concentration and a low concentration region in which the element existent at a low concentration is formed on a surface of a substrate made of aluminum, aluminum alloy or aluminum-containing composite material by existing at least one element other than aluminum selected from Group 2A, Group 3A, Group 4A and Group 4B in Periodic Table in a stepwise manner. Thereby, it is possible to form the nitriding portion which shows a high corrosion resistance property with respect to a halogen-based corrosive gas.

Abstract: A material with a low volume resistivity at room temperature composed of an aluminum nitride sintered body is provided. The sintered body contains samarium in a converted content calculated as samarium oxide of not lower than 0.04 mole percent, and the sintered body contains aluminum nitride phase and samarium-aluminum complex oxide phase. The samarium-aluminum complex oxide phase forms intergranular layers with a low resistivity along the intergranular phase between aluminum nitride grains.

Abstract: A method for producing an aluminum-containing member, comprising the steps of heating a substrate containing at least metallic aluminum in vacuum of not more than 10−3 torrs, and continuing with the heating step, forming a nitride in a surface portion of the substrate by heating/nitriding the substrate in a nitrogen atmosphere continuously to the above heating step.

Abstract: A halogen gas plasma-resistant member to be exposed to a halogen gas plasma, includes a main body of said member, and a corrosion-resistant film formed at least a surface of said main body, wherein a peeling resistance of the corrosive film to said main body is not less than 15 MPa.

Abstract: A unique recording medium having identification information such as a serial number or ID number inherent in each of recording media as information signals recorded thereon, which is prevented from being easily erased or rewritten, without inducing the complexity of an optical disc reproducing apparatus in its configuration and the intricacy of the reading-out operation is realized. Recognition information is recorded to a recording medium which has a recognition information recording area for recording the recognition information, and at least the recognition information recording area is capable of additionally having information recorded thereto. In recording digitized recognition information to the recognition information recording area, the “1” is modulated to a signal having a first frequency and the “0” is modulated to a signal having a second frequency, and the signals corresponding to their respective frequencies are written to the recognition information recording area.

Abstract: A composite sintered body produced from a glass powder and a powder of a conductive oxide, said sintered body having a glass phase and a conductive oxide phase dispersed in the glass phase, wherein the conductive oxide phase extends continuously three-dimensionally, and the composite sintered body has a volume resistance value of not more than 100 M&OHgr;·cm.

Abstract: A silicon nitride ceramic of the present invention possesses excellent strength of the surface, including a silicon nitride and a rare earth oxide compound and being characterized in that the ratio of the transverse rupture strength, at a room temperature, of the fired surface used as a tensile surface to the transverse rupture strength, at a room temperature, of the worked surface used as a tensile surface subjected to the working so as to have the surface roughness of R.sub.MAX 0.8 .mu.m or less is 0.7 or more, and the strength ratio is satisfied even when any portion besides the fired surface is utilized as the tensile surface to be worked to have the surface roughness of R.sub.MAX 0.8 .mu.m or less. The present invention also provides a process for producing a silicon nitride ceramic including the steps of: (1) mixing .alpha.-Si.sub.3 N.sub.4 powder and .beta.-Si.sub.3 N.sub.4 powder to obtain a raw material powder so as to satisfy the formula indicated by 0.05.ltoreq..beta./.alpha.+.beta..ltoreq.0.