Abstract: The present invention concerns a method for producing acrylic acid which involves subjecting an acrylic acid-containing aqueous solution obtained by catalytic vapor phase oxidation of propylene and/or acrolein to evaporation whereby an acrylic acid-containing vapor is obtained; and subjecting the acrylic acid-containing vapor to azeotropic dehydration. The present invention offers a number of advantages including a reduce amount of polymer that may adhere to the surface of an azeotropic dehydration column, a low-blowing separation column or an in a high-boiling separation column in a plant for producing acrylic acid. Consequently, the production plant can be operated for a long time without stopping operations.

Abstract: A mobile communication system including operation management of traffic machines, includes mobile radio terminals for receiving predetermined communication data, and which can be carried by a user of mobile communication; at least one traffic machine for transporting the user having the terminals; an operation management element for managing operation of the traffic machine by operation management data which are generated from predetermined operation data; and a line management element for managing radio lines used by the terminals on the basis of any one of position data and position change data of the terminals.

Abstract: The present invention provides a method for producing a methyl methacrylate polymer, wherein monomers containing methyl methacrylate as a main component are bulk-polymerized or solution-polymerized in the presence of a polymerization initiator and mercaptan compound as a chain transfer agent to form a liquid polymer composition containing unreacted monomers and then a volatile content is separated from the liquid polymer composition, the method comprising the steps of: distilling the volatile content to recover unreacted monomers, (1) subjecting the residue to a contact treatment with hydrazine compound or (2) subjecting the residue to an azeotropic distillation with water to remove impurities, distilling the resultant to recover the mercaptan compound and reusing the mercaptan compound as the chain transfer agent of raw materials.

Abstract: A mobile communication system including operation management of traffic machines, includes mobile radio terminals for receiving predetermined communication data, and which can be carried by a user of mobile communication; at least one traffic machine for transporting the user having the terminals; an operation management element for managing operation of the traffic machine by operation management data which are generated from predetermined operation data; and a line management element for managing radio lines used by the terminals on the basis of any one of position data and position change data of the terminals.

Abstract: A portable terminal includes a first store for storing a first physical address including a serial number of the terminal, a second store for storing a first logical address including a subscriber's telephone number, a third store for storing a second physical address of a hardware used for computer communication, a fourth store for storing a second logical address corresponding to the second physical address, an interface for radio LAN, and an interface for PHS system. When a call is originated, a first channel is connected by using the first physical address and the first logical address. The second physical address and the second logical address are transmitted to the network from the call originator's terminal through the first channel, thereby setting in a state enabling communication between computers, and necessary data is transmitted to the call originator's terminal through a second channel by communication between computers.

Abstract: A process for producing a carboxylic acid ester which comprises reacting a carboxylic acid with an alcohol in the presence of an acid catalyst to produce a reaction solution and neutralizing the reaction solution, characterized by using a countercurrently contacting column for neutralization, into which the esterified reaction solution is introduced at the lower portion of the column, an aqueous strong alkaline solution at a middle portion and an aqueous weak alkaline solution at an upper portion, removing a neutralized oil phase containing the carboxylic acid ester from the top of the column and removing an aqueous phase from the bottom, thereby continuously neutralizing the reaction solution.