摘要:
The present invention relates to a method for producing (meth)acrylic acid comprising a process of recovering (meth)acrylic acid as an aqueous (meth)acrylic acid from a (meth)acrylic acid-containing gas mixture produced by the catalytic gas phase oxidation of at least one reactant selected from the group consisting of propane, propylene, isobutylene and (meth)acrolein, and a system usable for the method. The recovery process comprises the steps of: (1) feeding the (meth)acrylic acid-containing gas mixture into a quenching tower and condensing it in the quenching tower so as to recover an aqueous (meth)acrylic acid solution from the bottom of the quenching tower, in which some of the recovered aqueous solution of (meth)acrylic acid is recycled to the top part of the quenching tower so as to condense the (meth)acrylic acid-containing gas mixture; (2) passing the uncondensed part of the (meth)acrylic acid-containing gas mixture from the quenching tower through the top of the quenching tower to an absorption column; (3) absorbing (meth)acrylic acid contained in the uncondensed part of the (meth)acrylic acid-containing gas mixture in the absorption column with a absorption solvent; (4) feeding the (meth)acrylic acid solution resulting from the absorption in the step (3) to a desorption column; and (5) separating the solvent used in the step (3) from the (meth)acrylic acid solution in the desorption column, so that the substance from which the solvent has been removed in the desorption column is fed to the quenching tower, and the separated solvent is recycled to the absorption column. The inventive method is an efficient and economic method which allows a reduction in energy consumption in subsequent purification processes by maximizing the concentration of an aqueous solution of (meth)acrylic solution recovered at the bottom of the quenching tower and minimizing the concentration of (meth)acrylic acid lost from the vent gas of the absorption column.
摘要:
Disclosed is a temperature measuring device. The temperature measuring device includes: a thermo-well tube; and a cable or wire type temperature measuring means which is installed in a thermo-well tube, wherein temperature measuring means has temperature detecting sensors disposed at an intermediate portion thereof, and the temperature detecting sensors can be moved axially in the thermo-well tube by applying tension to both ends of the cable or wire type temperature measuring means. The present invention also provides a reaction tube in which the temperature measuring device is disposed axially, and a reactor including at least one temperature measuring device or reaction tube as described above.
摘要:
Provided is a method of preparing styrene polymers, the method comprising: homogeneously mixing a styrene monomer; a cocatalyst mixture of Group 13 metal-containing organic metal compound cocatalyst and an inert organic solvent; and a catalyst mixture of a metallocene catalyst and the inert organic solvent using a high speed homogenizing mixer to obtain a homogenized mixture; and providing the homogenized mixture to a reactor to initiate polymerization. In this method, catalyst is quickly dispersed among monomers using a high speed homogenizing mixer so that formation of gel, which occurs when a syndiotactic styrene polymer is produced, can be fundamentally prevented. In addition, a styrene polymer prepared using the method has high activity, good stereoregularity, and uniform molecular distribution.
摘要:
Provided are a method and apparatus for providing a security mechanism guaranteeing transparency at a transport layer. The method includes: receiving a data packet from an application program, and searching key information corresponding to the data packet in key information database; determining whether to request a key exchange module of an application layer for a new key negotiation according to a result obtained by searching key information; and performing encrypting/decrypting based on key information when the key exchange module stores key negotiation information obtained by the new key negotiation in a kernel. The apparatus encrypts/decrypts the data packet at the transport layer of the kernel, thereby providing the application program with security transparency, effectively controlling and making it easily expansible.
摘要:
A prism sheet of an LCD includes a body part made of a transparent resin material and a plurality of polypyramid-shaped optical unit structures formed in a intaglio type on the body part. The plurality of optical unit structures have intaglio-type polypyramid shapes in an inside of their polygonal structure. A center of the intaglio portion corresponds to a vertex of the polypyramid, thereby forming a point.
摘要:
Provided is a microwave tunable device having a coplanar waveguide structure, comprising a substrate, a ferroelectric/paraelectric thin film, a first transmission line, and second transmission lines, wherein a transmission line portion is formed with a constant width and an input/output portion is formed with a width larger than that of the transmission line portion in the first transmission line, and a transmission line portion is formed with a constant width and an input/output portion is formed with a narrower width than that of the transmission line portion in the second transmission line, whereby it is possible to minimize impedance difference with a connection line, a reflection loss, and an insertion loss, by controlling the width of the first transmission line and gap between the first and the second transmission lines, in the input/output portion.
摘要:
A backlight assembly of a liquid crystal display is provided. The backlight assembly of a liquid crystal display include a lamp for generating light; a light guide plate disposed at a side of the lamp to guide the light; a diffusion sheet disposed on the light guide plate to scatter the light that is incident from the light guide plate, thereby making brightness distribution of light uniform; and a prism sheet including a body part into which a light diffused from the diffusion sheet is introduced and a plurality of protrusion parts arranged in a specific direction, in which each protrusion part is shaped in a scalene triangle prism form and has both base angles different from each other.
摘要:
Provided are a security router system for a network and a method of authenticating a user who connects to the system. The security routing system includes: a plurality of physical link ports inputting/outputting packets; a physical layer matching unit transmitting/receiving packets to the physical link ports and generating a media access control (MAC) frame; and a network processor including routing processing means that establishes a transport route for input packets via the physical layer matching unit and processes routing protocols, packet forwarding means that forward the input packets to their destinations, intrusion detection means that classify the input packets based on a packet classification standard and determine whether the input packets are attacks from outside, and user authentication means that determine whether a user is authorized to connect to a router, thereby reducing expenses required to build a network while maintaining security in comparison with a conventional firewall or intrusion detection system, and increasing reliability and safety of the network by preventing harmful traffic since each router performs a network security function.
摘要:
A backlight assembly of a liquid crystal display is provided. The backlight assembly of a liquid crystal display include a lamp for generating light; a light guide plate disposed at a side of the lamp to guide the light; a diffusion sheet disposed on the light guide plate to scatter the light that is incident from the light guide plate, thereby making brightness distribution of light uniform; and a prism sheet including a body part into which a light diffused from the diffusion sheet is introduced and a plurality of protrusion parts arranged in a specific direction, in which each protrusion part is shaped in a scalene triangle prism form and has both base angles different from each other.
摘要:
An apparatus and method for computing a SHA-1 hash function value are provided. The apparatus includes a first register unit including a plurality of registers that store a first bit string of predetermined lengths for generation of a hash function value; a second register unit storing input data in units of second bit strings with predetermined lengths, and sequentially outputting the second bit strings; a third register unit performing an operation on the first bit string of the plurality of registers and the second bit strings output from the second register unit so as to generate and store a third bit string, and updating first-bit string of the plurality of registers based on the third bit string; and an adding unit combining the first bit string stored in the first register unit, the first bit string of the third bit string stored in the third register unit, and the original initial values stored in the first register unit so as to obtain a hash function value. Accordingly, it is possible to reduce the size of the apparatus and stably compute a hash function value at a high speed.