Abstract: Methods of preparing reduced graphene oxide and reduced graphene oxide-polymer composites. The methods include covalently binding a halogen-substituted aromatic compounds to a graphene oxide and heat treating the graphene oxide with the halogen-substituted aromatic compounds covalently bound thereto at a low temperature, for example, 450° C. or less. By using the methods, reduced graphene oxide and reduced graphene oxide-polymer composites that have high electrical conductivities (e.g., 30,000 S/m or more) may be obtained.

Abstract: An antenna device includes: a feeding rod unit connected to a feeding unit, in which a radio signal is applied to be sent and received to the feeding unit; an end rod unit, disposed at the end of the antenna device, and spaced apart from the feeding rod unit; at least one intermediate rod unit, interposed between the feeding rod unit and the end rod unit; a first helical unit, interposed between the feeding rod unit and the at least one intermediate rod unit; and a second helical unit, interposed between the intermediate rod unit and the end rod unit.

Abstract: Provided are a method for post-treatment of a carbonaceous material using dehydrocyclization, a carbonaceous material post-treated by the method, and a polymer composite material including the carbonaceous material. More particularly, provided are a method for post-treatment of a carbonaceous material using dehydrocyclization, including subjecting the carbonaceous material to dehydrocyclization at room temperature to heal structural defects in the carbonaceous material, while increasing the effective conjugated length of the carbonaceous material to improve the electrical conductivity thereof, as well as a carbonaceous material post-treated by the method and a polymer composite material including the carbonaceous material.

Abstract: The present disclosure relates to a polyimide-graphene composite material and a method for preparing same. More particularly, it relates to a polyimide-graphene composite material prepared by adding modified graphene and a basic catalyst during polymerization of a polyimide precursor so as to improve mechanical strength and electrical conductivity and enable imidization at low temperature and a method for preparing same.

Abstract: Provided are a method for post-treatment of a carbonaceous material using dehydrocyclization, a carbonaceous material post-treated by the method, and a polymer composite material including the carbonaceous material. More particularly, provided are a method for post-treatment of a carbonaceous material using dehydrocyclization, including subjecting the carbonaceous material to dehydrocyclization at room temperature to heal structural defects in the carbonaceous material, while increasing the effective conjugated length of the carbonaceous material to improve the electrical conductivity thereof, as well as a carbonaceous material post-treated by the method and a polymer composite material including the carbonaceous material.

Abstract: An antenna apparatus having a device carrier made of a magneto-dielectric material is provided. The antenna apparatus includes a device carrier having a magnetic carrier made of a magneto-dielectric material, and an antenna device connectable to a power source through a feeding point of one end portion and extended from the feeding point to pass through a surface of the magnetic carrier and operable in a resonant frequency band when power is supplied through the feeding point. Therefore, by forming at least a portion of the device carrier with a magnetic carrier, an operating performance of the antenna apparatus can be improved.

Abstract: Disclosed herein is a wrongdoing reporting system and method, and a storage medium for the same. In the wrongdoing reporting method, a report of a wrongdoing is received from a reporter client, wherein the reporter client is a mobile client on which a wrongdoing reporting application is executed and the report of the wrongdoing includes an organization unique code, a report unique, and report details information. The report details information is transmitted to an organization client previously registered for the organization unique code. Results of actions against the report details information are received from the organization client, wherein the results of the actions include an organization unique code, a report unique code, and action result details information. The action result details information is transmitted to a reporter client corresponding to the report unique code.

Abstract: A method of making Y-type hexagonal ferrite and an antenna using the same are provided. Y-type hexagonal ferrite includes a base ferrite composed of iron oxide, barium carbonate and cobalt oxide, and silicate glass ranging from 0.5 to 5 weight percent added to 100 weight percent of base ferrite. An antenna apparatus includes a magnetic carrier and an antenna pattern formed thereon. The magnetic carrier is formed of such Y-type hexagonal ferrite, and the antenna pattern resonates in a specific frequency band when electric power is supplied. To fabricate the Y-type hexagonal ferrite, a calcination process is performed in which iron oxide, barium carbonate and cobalt oxide are combined into base ferrite at a given calcination temperature after being mixed. A sintering process is performed to sinter the base ferrite and the silicate glass at a given sintering temperature which is lower than the calcination temperature after adding the silicate glass to the base ferrite.

Abstract: A new magnetic substance having a high magnetic permeability and a low magnetic permeability loss over a wide frequency bandwidth, a composite material for antennas using the new magnetic substance and a polymer, and an antenna using the composite material for antennas.

Abstract: An antenna device includes: a feeding rod unit connected to a feeding unit, in which a radio signal is applied to be sent and received to the feeding unit; an end rod unit, disposed at the end of the antenna device, and spaced apart from the feeding rod unit; at least one intermediate rod unit, interposed between the feeding rod unit and the end rod unit; a first helical unit, interposed between the feeding rod unit and the at least one intermediate rod unit; and a second helical unit, interposed between the intermediate rod unit and the end rod unit.

Abstract: Methods of preparing reduced graphene oxide and reduced graphene oxide-polymer composites. The methods include covalently binding a halogen-substituted aromatic compounds to a graphene oxide and heat treating the graphene oxide with the halogen-substituted aromatic compounds covalently bound thereto at a low temperature, for example, 450° C. or less. By using the methods, reduced graphene oxide and reduced graphene oxide-polymer composites that have high electrical conductivities (e.g., 30,000 S/m or more) may be obtained.

Abstract: An antenna apparatus having a device carrier made of a magneto-dielectric material is provided. The antenna apparatus includes a device carrier having a magnetic carrier made of a magneto-dielectric material, and an antenna device connectable to a power source through a feeding point of one end portion and extended from the feeding point to pass through a surface of the magnetic carrier and operable in a resonant frequency band when power is supplied through the feeding point. Therefore, by forming at least a portion of the device carrier with a magnetic carrier, an operating performance of the antenna apparatus can be improved.

Abstract: A multiband antenna system installed onto a circuit board of a mobile device is provided. The antenna system includes a planar dielectric substrate, an upper conductor formed on an upper surface of the dielectric substrate and shaped as a coplanar wave guide and includes first and second ground parts and a radiator, and a lower conductor formed on the lower surface of the dielectric substrate and shaped as a coplanar wave guide and includes third and fourth ground parts and an electrode part, via-holes that pass through the dielectric substrate and are electrically connected to the first ground part to the third, the second ground part to the fourth, and the radiator to the electrode part, respectively, and solder balls connect the electrode part to an electric wire of the circuit board and also the third and fourth ground parts to the ground of the circuit board.

Abstract: A method of making Y-type hexagonal ferrite and an antenna using the same are provided. Y-type hexagonal ferrite includes a base ferrite composed of iron oxide, barium carbonate and cobalt oxide, and silicate glass ranging from 0.5 to 5 weight percent added to 100 weight percent of base ferrite. An antenna apparatus includes a magnetic carrier and an antenna pattern formed thereon. The magnetic carrier is formed of such Y-type hexagonal ferrite, and the antenna pattern resonates in a specific frequency band when electric power is supplied. To fabricate the Y-type hexagonal ferrite, a calcination process is performed in which iron oxide, barium carbonate and cobalt oxide are combined into base ferrite at a given calcination temperature after being mixed. A sintering process is performed to sinter the base ferrite and the silicate glass at a given sintering temperature which is lower than the calcination temperature after adding the silicate glass to the base ferrite.

Abstract: The present invention relates to a metal nozzle boss provided with a sealing device, which has highly improved tightness and is combined with a plastic liner of a composite vessel used as a high-pressure vessel. The metal nozzle boss uses an elastic seal ring and a tightening piece in the plastic liner, so that the nozzle boss reliably seals the junction of the nozzle boss and the liner and prevents gas leakage from the vessel. The blade part of the nozzle boss has a dovetail-shaped locking groove, with locking ridges formed in the locking groove. Thus, when the plastic liner is produced by injecting molten resin into the locking groove, the plastic liner is securely combined with the metal nozzle boss. The composite vessel having the metal nozzle boss can be used as a fuel tank for natural gas vehicles or a hydrogen tank for fuel cell vehicles.

Abstract: A multi-stage operation type air conditioner which can be operated in various cooling or heating capacities. The multi-stage operation type air conditioner includes a first discharge port, a first opening/closing device for opening or closing the first discharge port, a second discharge port having a size different from that of the first discharge port, a second opening/closing device for opening or closing the second discharge port, and a controller for controlling the air conditioner such that the air conditioner may be operated with one of the first and second discharge ports opened, in an operation with a lower cooling or heating load, and the air conditioner may be operated with both the first and second discharge ports opened, in an operation with a higher cooling or heating load.

Abstract: An antenna includes a dielectric substrate on which a via hole is formed; a radiation patch attached onto the dielectric substrate and connected to the via hole; a ring-shaped first radiation pattern formed on the dielectric substrate and has a part connected to the radiation patch; and a ring-shaped second radiation pattern formed on the dielectric substrate and has a part connected to the radiation patch. The radiation patch, the first radiation pattern and the second radiation pattern each receive a feeding through the via hole, and operate in different frequency bands. The antenna device for a portable terminal has the radiation patch and the first and second radiation patterns, which resonate in different frequency bands, so that it can operate in various frequency bands.

Abstract: A method and apparatus for compensating for temperature characteristics of a laser diode are disclosed. The laser diode may be used in a transmitter unit of a transceiver for optical signal transmission. The transceiver includes the laser diode and a monitor photodiode. In such a method, a modulation current is derived from an input voltage and arbitrary variables. Variations of overall modulation resistance values corresponding to an operation temperature range are evaluated by a relation between the modulation current and the overall modulation resistance, and the overall modulation resistance values are determined according to the variations. Also, variations of overall bias resistance values corresponding to the temperature range are evaluated by a current Impd of the photodiode, which is derived at specific optical power arbitrarily chosen in the temperature range. The overall bias resistance values are determined according to the variations.

Abstract: A point-to-multi-point passive optical network (PON) includes: an optical line terminal (OLT) comprising an optical transceiver for generating a downstream optical signal and a monitoring signal and for detecting an upstream optical signal; a plurality of optical network units (ONUs) for detecting the downstream optical signal, reflecting the monitoring signal to the OLT, and transmitting a data-modulated upstream optical signal in a designated time slot; and an optical fiber for connecting the ONUs and the OLT.

Abstract: A bi-directional optical transceiver includes: an optical fiber for transmitting and receiving first and second optical signals; a transmitter module for generating the first optical signal; a receiver module for detecting the second optical signal; a tap filter for splitting a portion of the first optical signal; a monitor module for monitoring the magnitude of the portion of the first optical signal split by the tap filter; and a wavelength selection filter, which is located between the tap filter and the optical fiber, inputs the first optical signal output from the tap filter into the optical fiber, and inputs the second optical signal output from the optical fiber into an optical detector.