Abstract: A reduced iron production method includes: a reduction-step of producing reduced iron by heating an agglomerate containing iron oxide and carbonaceous reducing agent to reduce the iron oxide and solidifying a product produced by melting the reduced iron; a first-magnetic-separation-step of separating, among granular metallic iron, first slag, and second slag containing more fine-granular metallic iron than the first slag that are contained in the product, at least the granular metallic iron from the first slag by use of a first magnetic separator to separate first slag containing substance and a granular metallic iron containing substance from each other; a second-magnetic-separation-step of separating the second slag from the first slag containing substance or the granular metallic iron containing substance by use of a second magnetic separator having attraction force different from attraction force of the first magnetic separator; and a crushing-step of crushing the second slag.

Abstract: A rotary hearth furnace includes: a furnace body which surrounds a ring-like space; a hearth portion which forms a bottom portion of the ring-like space and is rotatable in the rotational direction; a gas exhaust portion which discharges an exhaust gas generated in the ring-like space to the outside of the furnace body; an introducing portion; and a flow rate regulating portion. The introducing portion is disposed upstream of the gas exhaust portion in the rotational direction and introduces a pressure regulating gas into a non-heating section of the ring-like space. The flow rate regulating portion is disposed between the introducing portion and the gas exhaust portion and regulates a flow rate of a gas by adjusting an opening area of the non-heating section.

Abstract: A method and a device for charging a plurality of reduced iron raw materials into a traveling hearth reduction-melting furnace and treating the raw materials, allowing sufficient input of heat to the reduced iron raw materials on a hearth covering material to improve treatment efficiency are provided. The reduced iron raw materials are released downward from the lower surface of a ceiling of the reduction-melting furnace to be set on a hearth covering material on a hearth and reduced on the hearth covering material. The falling reduced iron raw materials are given a horizontal velocity having a direction equal to the travel direction of the hearth and being greater than the travel speed of the hearth to enable the reduced iron raw materials to roll in the same direction as the travel direction of the hearth after landing on the hearth covering material.

Abstract: A rotary hearth furnace includes: a furnace body which surrounds a ring-like space; a hearth portion which forms a bottom portion of the ring-like space and is rotatable in the rotational direction; a gas exhaust portion which discharges an exhaust gas generated in the ring-like space to the outside of the furnace body; an introducing portion; and a flow rate regulating portion. The introducing portion is disposed upstream of the gas exhaust portion in the rotational direction and introduces a pressure regulating gas into a non-heating section of the ring-like space. The flow rate regulating portion is disposed between the introducing portion and the gas exhaust portion and regulates a flow rate of a gas by adjusting an opening area of the non-heating section.

Abstract: A reduced iron production method includes: a reduction-step of producing reduced iron by heating an agglomerate containing iron oxide and carbonaceous reducing agent to reduce the iron oxide and solidifying a product produced by melting the reduced iron; a first-magnetic-separation-step of separating, among granular metallic iron, first slag, and second slag containing more fine-granular metallic iron than the first slag that are contained in the product, at least the granular metallic iron from the first slag by use of a first magnetic separator to separate first slag containing substance and a granular metallic iron containing substance from each other; a second-magnetic-separation-step of separating the second slag from the first slag containing substance or the granular metallic iron containing substance by use of a second magnetic separator having attraction force different from attraction force of the first magnetic separator; and a crushing-step of crushing the second slag.

Abstract: A method and a device for charging a plurality of reduced iron raw materials into a traveling hearth reduction-melting furnace and treating the raw materials, allowing sufficient input of heat to the reduced iron raw materials on a hearth covering material to improve treatment efficiency are provided. The reduced iron raw materials are released downward from the lower surface of a ceiling of the reduction-melting furnace to be set on a hearth covering material on a hearth and reduced on the hearth covering material. The falling reduced iron raw materials are given a horizontal velocity having a direction equal to the travel direction of the hearth and being greater than the travel speed of the hearth to enable the reduced iron raw materials to roll in the same direction as the travel direction of the hearth after landing on the hearth covering material.

Abstract: Not only the cracking of granular reduced iron materials is reduced, but also reduced iron materials are fed uniformly onto a furnace floor regardless of a width of the furnace floor. A feeding system for reduced iron material includes a plurality of material feeding equipments 4 provided in a furnace width direction of a mobile furnace floor type reduction melting furnace, wherein each of the material feeding equipments 4 is constructed by a hopper 10 configured to receive reduced iron materials and discharge the materials from a discharge port 10a, a trough 14 configured to connect the discharge port 10a and a material charging portion of the mobile furnace floor type reduction melting furnace configured to receive the reduced iron materials discharged from the discharge port 10a, an exit portion provided on an exit side of the trough 14, and a vibration applying unit configured to cause the trough to vibrate along a furnace floor moving direction.

Abstract: Affords Group-III nitride single-crystal ingots and III-nitride single-crystal substrates manufactured utilizing the ingots, as well as methods of manufacturing III-nitride single-crystal ingots and methods of manufacturing III-nitride single-crystal substrates, wherein the incidence of cracking during length-extending growth is reduced. Characterized by including a step of etching the edge surface of a base substrate, and a step of epitaxially growing onto the base substrate hexagonal-system III-nitride monocrystal having crystallographic planes on its side surfaces. In order to reduce occurrences of cracking during length-extending growth of the ingot, depositing-out of polycrystal and out-of-plane oriented crystal onto the periphery of the monocrystal must be controlled.

Abstract: A group III nitride semiconductor crystal substrate has a diameter of at least 25 mm and not more than 160 mm. The resistivity of the group III nitride semiconductor crystal substrate is at least 1×10?4 ?·cm and not more than 0.1 ?·cm. The resistivity distribution in the diameter direction of the group III nitride semiconductor crystal is at least ?30% and not more than 30%. The resistivity distribution in the thickness direction of the group III nitride semiconductor crystal is at least ?16% and not more than 16%.

Abstract: Not only the cracking of granular reduced iron materials is reduced, but also reduced iron materials are fed uniformly onto a furnace floor regardless of a width of the furnace floor. A feeding system for reduced iron material includes a plurality of material feeding equipments 4 provided in a furnace width direction of a mobile furnace floor type reduction melting furnace, wherein each of the material feeding equipments 4 is constructed by a hopper 10 configured to receive reduced iron materials and discharge the materials from a discharge port 10a, a trough 14 configured to connect the discharge port 10a and a material charging portion of the mobile furnace floor type reduction melting furnace configured to receive the reduced iron materials discharged from the discharge port 10a, an exit portion provided on an exit side of the trough 14, and a vibration applying unit configured to cause the trough to vibrate along a furnace floor moving direction.

Abstract: Affords a GaN single-crystal mass, a method of its manufacture, and a semiconductor device and method of its manufacture, whereby when the GaN single-crystal mass is being grown, and when the grown GaN single-crystal mass is being processed into a substrate or like form, as well as when an at least single-lamina semiconductor layer is being formed onto a single-crystal GaN mass in substrate form to manufacture semiconductor devices, cracking is controlled to a minimum. The GaN single-crystal mass 10 has a wurtzitic crystalline structure and, at 30° C., its elastic constant C11 is from 348 GPa to 365 GPa and its elastic constant C13 is from 90 GPa to 98 GPa; alternatively its elastic constant C11 is from 352 GPa to 362 GPa.

Abstract: There is provided a method for fabricating a gallium nitride crystal with low dislocation density, high crystallinity, and resistance to cracking during polishing of sliced pieces by growing the gallium nitride crystal using a gallium nitride substrate including dislocation-concentrated regions or inverted-polarity regions as a seed crystal substrate. Growing a gallium nitride crystal 79 at a growth temperature higher than 1,100° C. and equal to or lower than 1,300° C. so as to bury dislocation-concentrated regions or inverted-polarity regions 17a reduces dislocations inherited from the dislocation-concentrated regions or inverted regions 17a, thus preventing new dislocations from occurring over the dislocation-concentrated regions or inverted-polarity regions 17a. This also increases the crystallinity of the gallium nitride crystal 79 and its resistance to cracking during the polishing.

Abstract: There is provided a method for fabricating a gallium nitride crystal with low dislocation density, high crystallinity, and resistance to cracking during polishing of sliced pieces by growing the gallium nitride crystal using a gallium nitride substrate including dislocation-concentrated regions or inverted-polarity regions as a seed crystal substrate. Growing a gallium nitride crystal 79 at a growth temperature higher than 1,100° C. and equal to or lower than 1,300° C. so as to bury dislocation-concentrated regions or inverted-polarity regions 17a reduces dislocations inherited from the dislocation-concentrated regions or inverted regions 17a, thus preventing new dislocations from occurring over the dislocation-concentrated regions or inverted-polarity regions 17a. This also increases the crystallinity of the gallium nitride crystal 79 and its resistance to cracking during the polishing.

Abstract: Affords GaxIn1-xN substrates onto which high-quality epitaxial films can be stably grown, and cleaning methods for manufacturing the GaxIn1-xN substrates. GaxIn1-xN substrate in which the number of particles of not less than 0.2 ?m particle size present on the GaxIn1-xN substrate surface is 20 or fewer, given that the GaxIn1-xN substrate diameter is 2 inches. Furthermore, a GaxIn1-xN substrate in which, in a photoelectron spectrum along the surface by X-ray photoelectron spectroscopy at a take-off angle of 10°, the ratio between the peak areas of the C1s electron and N1s electron (C 1s electron peak area/N 1s electron peak area) is not greater than 3.

Abstract: An AlxGayIn1-x-yN crystal substrate of the present invention has a main plane having an area of at least 10 cm2. The main plane has an outer region located within 5 mm from an outer periphery of the main plane, and an inner region corresponding to a region other than the outer region. The inner region has a total dislocation density of at least 1×102 cm?2 and at most 1×106 cm?2. It is thereby possible to provide an AlxGayIn1-x-yN crystal substrate having a large size and a suitable dislocation density for serving as a substrate for a semiconductor device, a semiconductor device including the AlxGayIn1-x-yN crystal substrate, and a method of manufacturing the same.

Abstract: Affords Group-III nitride single-crystal ingots and III-nitride single-crystal substrates manufactured utilizing the ingots, as well as methods of manufacturing III-nitride single-crystal ingots and methods of manufacturing III-nitride single-crystal substrates, wherein the incidence of cracking during length-extending growth is reduced. Characterized by including a step of etching the edge surface of a base substrate, and a step of epitaxially growing onto the base substrate hexagonal-system III-nitride monocrystal having crystallographic planes on its side surfaces. In order to reduce occurrences of cracking during length-extending growth of the ingot, depositing-out of polycrystal and out-of-plane oriented crystal onto the periphery of the monocrystal must be controlled.

Abstract: Affords a GaN single-crystal mass, a method of its manufacture, and a semiconductor device and method of its manufacture, whereby when the GaN single-crystal mass is being grown, and when the grown GaN single-crystal mass is being processed into a substrate or like form, as well as when an at least single-lamina semiconductor layer is being formed onto a single-crystal GaN mass in substrate form to manufacture semiconductor devices, cracking is controlled to a minimum. The GaN single-crystal mass 10 has a wurtzitic crystalline structure and, at 30° C., its elastic constant C11 is from 348 GPa to 365 GPa and its elastic constant C13 is from 90 GPa to 98 GPa; alternatively its elastic constant C11 is from 352 GPa to 362 GPa.

Abstract: A group III nitride semiconductor crystal substrate has a diameter of at least 25 mm and not more than 160 mm. The resistivity of the group III nitride semiconductor crystal substrate is at least 1×10?4 ?·cm and not more than 0.1 ?·cm. The resistivity distribution in the diameter direction of the group III nitride semiconductor crystal is at least ?30% and not more than 30%. The resistivity distribution in the thickness direction of the group III nitride semiconductor crystal is at least ?16% and not more than 16%.

Abstract: An AlxGayIn1-x-yN crystal substrate of the present invention has a main plane having an area of at least 10 cm2. The main plane has an outer region located within 5 mm from an outer periphery of the main plane, and an inner region corresponding to a region other than the outer region. The inner region has a total dislocation density of at least 1×102 cm?2 and at most 1×106 cm-31 2. It is thereby possible to provide an AlxGayIn1-x-yN crystal substrate having a large size and a suitable dislocation density for serving as a substrate for a semiconductor device, a semiconductor device including the AlxGayIn1-x-yN crystal substrate, and a method of manufacturing the same.

Abstract: There is provided a method for fabricating a gallium nitride crystal with low dislocation density, high crystallinity, and resistance to cracking during polishing of sliced pieces by growing the gallium nitride crystal using a gallium nitride substrate including dislocation-concentrated regions or inverted-polarity regions as a seed crystal substrate. Growing a gallium nitride crystal 79 at a growth temperature higher than 1,100° C. and equal to or lower than 1,300° C. so as to bury dislocation-concentrated regions or inverted-polarity regions 17a reduces dislocations inherited from the dislocation-concentrated regions or inverted regions 17a, thus preventing new dislocations from occurring over the dislocation-concentrated regions or inverted-polarity regions 17a. This also increases the crystallinity of the gallium nitride crystal 79 and its resistance to cracking during the polishing.