Abstract: To precisely predict the distribution of densities and sizes of void defects comprising voids and inner wall oxide membranes in a single crystal. The computer-based simulation determines, at steps 1 to 7, the distribution of temperatures within a single crystal 14 growing from a melt 12 from the time of its pulling-up to the time of its completing cooling with due consideration paid to convection currents in the melt 12. The computer-based simulation, at steps 8 to 15, determines the density of voids considering the cooling process of the single crystal separated from the melt, that is, the pulling-up speed of the single crystal after the separation from the melt, and reflecting the effect of slow and rapid cooling of the single crystal in the result, and relates the radius of voids with the thickness of inner wall oxide membrane developed around the voids.

Abstract: The axial temperature gradient G at the vicinity of the solid-liquid interface 24 in an ingot is calculated in consideration of the heating value of a heater 18, the dimensions and physical property values of furnace inside components and the convection of the melt 12 before pulling up the single crystal ingot 15 by a puller 10 by use of a numerical simulation of synthetic heater transfers and a numerical simulation of melt convection. Then, the pulling velocity V of the single crystal ingot is determined from an value experienced of the ratio C=V/G of the pulling velocity V and the axial temperature gradient G of the single crystal ingot at which the single crystal ingot becomes defect-free, obtained when the single crystal ingot was pulled up by a same type puller as the puller in the past, and the axial temperature gradient G calculated by use of the simulations.

Abstract: A vapor phase epitaxial growth apparatus, comprising a chamber, to which a wafer is fed; a gas introduction device for introducing a reaction gas into the chamber; a gas flow amount sensor for detecting a flow amount of the reaction gas introduced by the gas introduction device; heaters for heating the wafer fed into the chamber; a heat adjusting device for adjusting heating energy by the heaters; a temperature sensors for detecting a temperature of the wafer fed into the chamber; a control device for receiving as parameters a gas flow amount detected by the gas flow amount sensor and a wafer temperature detected by the temperature sensors, obtaining an optimal value of heating energy for attaining the most uniform epitaxial film based on a predetermined simulation-model, and outputting the same to the heat adjusting device.

Abstract: A first step models a hot zone in a pulling apparatus of a single crystal as a mesh structure, and a second step inputs physical property values of each member corresponding to meshes combined for each member of the hot zone into a computer. A third step obtains the surface temperature distribution of each member on the basis of the calorific power of a heater and the emissivity of each member, and a fourth step obtains the internal temperature distribution of each member on the basis of the surface temperature distribution and the thermal conductivity of each member, and then further obtains the internal temperature distribution of a molten liquid being in consideration of convection. A fifth step obtains the shape of the solid-liquid interface between the single crystal and the molten liquid in accordance with an isothermal line including a tri-junction of the single crystal. A sixth step repeats said third to fifth steps until the tri-junction becomes the melting point of the single crystal.

Abstract: A first step models a hot zone in a pulling apparatus of a single crystal as a mesh structure, and a second step inputs physical property values of each member corresponding to meshes combined for each member of the hot zone into a computer. A third step obtains the surface temperature distribution of each member on the basis of the calorific power of a heater and the emissivity of each member, and a fourth step obtains the internal temperature distribution of each member on the basis of the surface temperature distribution and the thermal conductivity of each member, and then further obtains the internal temperature distribution of a molten liquid being in consideration of convection. A fifth step obtains the shape of the solid-liquid interface between the single crystal and the molten liquid in accordance with an isothermal line including a tri-junction of the single crystal. A sixth step repeats said third to fifth steps until the tri-junction becomes the melting point of the single crystal.

Abstract: A phase lock loop (PLL) circuit has an oscillation circuit operating in synchronism with a horizontal synchronizing signal. The PLL circuit also has a DC level decision circuit for deciding the DC level of a vertical synchronizing signal during a return period, and a logic circuit for automatically selecting the oscillation circuit according to the DC level decided in the DC level decision unit. Thus, even if there is an increase in the oscillation characteristics, this PLL circuit can automatically select the necessary oscillation characteristics without a need for expanding an operation frequency of a voltage controlled oscillation circuit.

Abstract: In a network, an inter-network connection unit is connected to perform transmission of data between the network and another network. The inter-network connection unit is furthermore connected to a multiplexer. Between the multiplexer and another multiplexer to which an inter-network unit installed in the other network is connected, data transmission is performed via a multiplex line. The multiplexer changes the communication capacity of a communication line connecting the inter-network connection unit to the multiplexer in accordance with the data transmission quantity between the multiplexer and the inter-network connection unit connected thereto and dynamically changes the communication band assigned to the inter-network connection unit in accordance with the change of the communication capacity.

Abstract: A line switching apparatus for switching from a telecommunication line to a backup line in the event of occurrence of a fault on the telecommunication line includes a memory storing time zone information for monitoring the state of the telecommunication line, so that, when occurrence of a fault is detected during this monitoring time zone, the line switching apparatus switches from the faulty telecommunication line to a backup line, while when the time is outside the monitoring time zone, the state of the telecommunication line is not monitored so as to prevent unnecessary switching from the telecommunication line to the backup line.

Abstract: A method of and apparatus for controlling a data transfer by a transfer deliverer node from a terminal equipment belonging to the transfer deliverer node to another node, in a network system having a plurality of nodes connected to a public switched network and a plurality of terminal equipments connectable to a corresponding node.

Abstract: A network system in which a plurality of computers and a terminal device are connected to one another through a node by telecommunication lines, and one computer is designated by the terminal device to communicate data with the terminal device through the node, the node detects a stop or fault of the one computer, or a stop or fault of the telecommunication line connecting the one computer and the node to each other, in response to an incoming call for the one computer from the terminal device, and informs the terminal device of the stop or fault, in response to the detection of the stop or fault.

Abstract: An apparatus for growing a single crystal is disclosed which includes a double crucible assembly. The double crucible assembly has an outer crucible and an inner crucible disposed in the outer crucible. A support member is provided for supporting the inner crucible, and the support member is formed of an inorganic oxide non-reactive with silicon oxide. The upper end portion of the inner crucible may be formed of the same inorganic oxide. Alumina or mullite is suitable as the inorganic oxide. With the above construction, silicon single crystals obtained by the crystal growing apparatus will be free of contamination by carbon or heavy metals, and will exhibit excellent quality.

Abstract: In a network system in which a line switching unit and the other line switching unit are connected with each other via communication lines and backup lines, and nodes which are connected with both the line switching units, respectively are adapted to communicate with each other via either one of the communication lines and backup lines and both line switching units, a line switching system wherein a network control unit is connected with the line switching units, said network control unit having, in a table, information on connecting mates of said communication and backup lines an information on a plurality of groups of communication lines each grouped based upon the former information, the network control unit being adapted to select a relevant group based upon the group information when a failure occurs in the communication lines for issuing an instruction for collectively switching a plurality of communication lines belonged to the group, whereby said line switching unit which has received the instruction

Abstract: In apparatuses for melting semiconductor material and growing single crystals of semiconductor material, the apparatus comprising:(a) a furnace,(b) a cylindrical double crucible assembly comprising an inner crucible in which single crystals of semiconductor material are grown at a vertical-concentric line thereof, the inner crucible having an upper part and a lower part, and an outer crucible in which melted semiconductor material is received, the outer crucible having the inner crucible disposed therein,(c) a susceptor for supporting the outer crucible,(d) rotating means for rotating the susceptor,(e) a feed pipe for supplying starting material in the space formed between the inner and the outer crucibles,(f) fluid-passage means for permitting the melted semiconductor material to flow between the inner and outer crucibles, the fluid-passage means being disposed at the lower part of the inner crucible, andwherein the inner crucible being set inside the outer crucible in a separable manner, the apparatus impro

Abstract: A network system includes a plurality of nodes connected to each other via line switching units through communication lines and backup lines and a network control unit connected to the line switching units. At an occurrence of a communication line failure, the network control unit supplies the line switching units with a line switching instruction to change over from the failed line to backup lines.

Abstract: A crystal growing apparatus includes a crucible, a feed pipe and a pulling mechanism. The crucible serves to melt a crystalline material. The feed pipe serves to cause the crystalline material to fall into the crucible to charge the crucible with the crystalline material. The pulling mechanism serves to pull a single-crystal from the molten material in the crucible. The feed pipe has a lower end positioned slightly above the surface of the molten material in the crucible and including a plurality of baffle plates mounted on an inner peripheral wall thereof in longitudinally spaced relation to one another. The baffle plates are arranged so that a pitch defined between adjacent two baffle plates decreases toward the lower end of the feed pipe.

Abstract: In a method for pulling a single crystal, employing a double crucible assembly, the dopant concentration of the molten raw material in an inner crucible prior to the pulling, is raised to a value higher than the dopant concentration C of the molten raw material in the inner crucible at the steady state. Furthermore, at the initial stage of the pulling, the raw material having a dopant content ratio of no greater than kC is introduced into the outer crucible at a rate greater than the rate of decrease of the molten raw material within the inner crucible during the pulling, to achieve a concentration ratio of dopant between the inner and outer crucibles at a target value. Subsequently, the raw material having kC as the dopant content ratio is introduced into the outer crucible, at a rate equal to the rate of decrease of the molten raw material during the pulling.