Abstract: A nickel-containing steel for low temperature service having a determined chemical composition of a Ni content of from 5.0 to 8.0%, in which the volume fraction of retained austenite in a region of 1.5 mm from a surface in the thickness direction is from 3.0 to 20.0% by volume, and the ratio of the hardness in a region of 1.0 mm from a surface in the thickness direction to the hardness in a region of ¼ of the thickness from a surface in the thickness direction is 1.1 or less, and a low-temperature tank using the nickel-containing steel for low temperature service.

Abstract: A nickel-containing steel plate for use at a low temperature, having a predetermined chemical composition, in which the volume fraction of retained austenite at a position 1.5 mm from the surface of the steel plate in the thickness direction is from 3.0 to 20.0% by volume; in which the maximum distance between adjacent grains of retained austenite on prior austenite grain boundaries at the position 1.5 mm from the surface of the steel plate in the thickness direction is 12.5 ?m or less; and in which the circle equivalent diameter of grains of retained austenite at a position corresponding to ¼ of the plate thickness from the surface of the steel plate in the thickness direction is 2.5 ?m or less. A tank for use at a low temperature, which is produced using the above described nickel-containing steel plate for use at a low temperature.

Abstract: The present invention provides a nickel-containing steel plate for use at a low temperature, having a predetermined chemical composition, in which the volume fraction of retained austenite at a position 1.5 mm from the surface of the steel plate in the thickness direction is from 3.0 to 20.0% by volume; in which the maximum distance between adjacent grains of retained austenite on prior austenite grain boundaries at the position 1.5 mm from the surface of the steel plate in the thickness direction is 12.5 ?m or less; and in which the circle equivalent diameter of grains of retained austenite at a position corresponding to ¼ of the plate thickness from the surface of the steel plate in the thickness direction is 2.5 ?m or less. The present invention also provides and a tank for use at a low temperature, which is produced using the above described nickel-containing steel plate for use at a low temperature.

Abstract: A nickel-containing steel for low temperature service having a determined chemical composition of a Ni content of from 5.0 to 8.0%, in which the volume fraction of retained austenite in a region of 1.5 mm from a surface in the thickness direction is from 3.0 to 20.0% by volume, and the ratio of the hardness in a region of 1.0 mm from a surface in the thickness direction to the hardness in a region of ¼ of the thickness from a surface in the thickness direction is 1.1 or less, and a low-temperature tank using the nickel-containing steel for low temperature service.

Abstract: A communication system that is constituted by a plurality of communication apparatuses, and performs time synchronization using a time synchronization frame, wherein one of the communication apparatuses is set as a starting point node, at least one of the communication apparatuses is set as a terminal point node, the starting point node generates a time synchronization frame in an outward-route direction and transmits the generated time synchronization frame in the outward-route direction, the terminal point node generates a time synchronization frame in a return-route direction and transmits the generated time synchronization frame in the return-route direction, and an intermediate node relays a received time synchronization frame when receiving a time synchronization frame transmitted in an outward-route direction and a return-route direction.

Abstract: A communication apparatus operates as a node of a network. The communication apparatus includes a port-state managing unit that updates, every time failure occurrence in the network is detected, state information indicating a state of the network, a database updating unit that updates, based on a transmission source address and a reception port of a received frame and the state information managed by the port-state managing unit, a database that determines an output port when a frame in which the transmission source address is a destination address is received, and an output-destination determining unit that determines an output port of the received frame by searching through the database using, as search keys, the destination address of the received frame and the state information managed by the port-state managing unit.

Abstract: A node functions as an inter-ring connection node connected to an inter-ring connection link in a communication system including a plurality of inter-ring connection links connected between adjacent ring networks. The node includes: a flow-information-pass determination unit that decides which of the inter-ring connection links a reception frame passes through, based on flow information that is stored in the frame for identifying flow to which the frame belongs; and a forwarding-destination-port decision unit that decides that a forwarding destination of the reception frame is an inter-ring connection link to which the own node is connected when the inter-ring connection link decided by the flow-information-pass determination unit is the inter-ring connection link to which the own node is connected, in the case where a destination of the reception frame is in an adjacent ring network.

Abstract: A communication apparatus operates as a node of a network. The communication apparatus includes a port-state managing unit that updates, every time failure occurrence in the network is detected, state information indicating a state of the network, a database updating unit that updates, based on a transmission source address and a reception port of a received frame and the state information managed by the port-state managing unit, a database that determines an output port when a frame in which the transmission source address is a destination address is received, and an output-destination determining unit that determines an output port of the received frame by searching through the database using, as search keys, the destination address of the received frame and the state information managed by the port-state managing unit.

Abstract: A communication system that is constituted by a plurality of communication apparatuses, and performs time synchronization using a time synchronization frame, wherein one of the communication apparatuses is set as a starting point node, at least one of the communication apparatuses is set as a terminal point node, the starting point node generates a time synchronization frame in an outward-route direction and transmits the generated time synchronization frame in the outward-route direction, the terminal point node generates a time synchronization frame in a return-route direction and transmits the generated time synchronization frame in the return-route direction, and an intermediate node relays a received time synchronization frame when receiving a time synchronization frame transmitted in an outward-route direction and a return-route direction.

Abstract: A communication network includes a plurality of user networks that accommodates IP terminals and does not perform a call control function, a core network (a call control network) that is located among the user networks and performs a call control function and a call management function, and a gateway that connects the user networks to the core network. The gateway receives a communication request packet from the user network or a data packet that is initially transmitted, and analyzes the packet. Thus, the gateway establishes a necessary call in the core network to allow an IP packet to pass through the core network.

Abstract: A multicast connection control apparatus provided in a branching-and-consolidating node connecting a source terminal to a plurality of destination terminals for branching information over the forward connection or consolidating information over the backward connection in a multicast connection ATM network system includes a congested status management table for managing congested status in all RM cells and a controller. The controller transmits only an uncongested status RM cell transmitted thereto last over the backward connection when all the connections in a sequence are found to be in the uncongested state. The controller also transmits only a congested status RM cell over the backward connection when one of the connections is found to be in the congested state and cancels the subsequent transmission of the congested status RM cells in the same sequence over the backward connection.

Abstract: An asynchronous transfer mode (ATM) communication network system is constructed by connecting a plurality of ATM terminal communication devices to each other through connections. Each ATM terminal communication device has a transmission function to transmit an output ATM cell and a receiving function to receive an input ATM cell.

Abstract: In an ATM communication network system comprising plural ATM terminals 1a to if respectively having individual real memories 38a to 38f to transmit and receive ATM cells and ATM switching apparatus 2a, 2c and 2e for switching the ATM cells transmitted and received among the ATM terminals 1a to if and setting a broadcast connection 4a designating the respective ATM terminals 1a to if as the transmitting ATM terminals, the virtual memory 3 may be realized on the real memories 38a to 38f of the ATM terminals 1a to if by periodically performing the broadcast cell communications using the broadcast connection 4a designating all the ATM terminals 1a to if in the present system as the transmitting apparatuses.