Abstract: A photovoltaic power conditioning system and method is provided. The system includes an isolated DC/DC converter (41), a DC/AC inverter (42), and a sine filter (43). The isolated DC/DC converter (41) receives a DC voltage from a solar cell through a parallel connection structure and converts the DC voltage into another DC voltage and then outputs the converted DC voltage through a series connection structure. The DC/AC inverter (42) converts the DC voltage output from the isolated DC/DC converter into an AC voltage. The sine filter (43) performs sine filtering on the AC voltage output from the DC/AC inverter and outputs the filtered AC voltage. The system employs a topology allowing it to be responsible for part of the output capacity, thereby significantly reducing the required capacity and increasing the system efficiency, so that the system can be applied to small and large-capacity photovoltaic power generation.

Abstract: The present invention relates to an apparatus for controlling the operation of an LED and to a method for controlling the drive current thereof. More particularly, the present invention relates to an apparatus for controlling the operation of an LED, which is capable of driving a direct current-operated LED module or an alternating current-operated LED module using alternating current power, and to a method for controlling the drive current of the apparatus. According to the present invention, the drive current of an LED array can be output in the form of a sine wave by a constant-current regulation or constant-power regulation even when input voltage varies, thus suppressing harmonics, improving the power factor, minimizing flicker, and preventing a temperature increase in the LED array and in an LED operation control circuit.

Abstract: The present invention relates to a catalyst composition for the synthesis of multi-walled carbon nanotube having high apparent density in a manner of high yield. More particularly, this invention relates to a multi-component metal catalyst composition comprising i) main catalyst of Fe and Mo, ii) inactive support of Al and iii) optional co-catalyst at least one selected from Co, Ni, Ti, Mn, W, Sn or Cu. Further, the present invention affords multi-walled carbon nanotube having 5˜15 nm of fibrous diameter and 0.5˜4 ?m bundle diameter.

Abstract: The present invention relates to a catalyst composition for the synthesis of thin multi-walled carbon nanotube(MWCNT). More particularly, this invention relates to a multi-component metal catalyst composition comprising i) main catalyst of Co and Al, ii) inactive support of Mg and iii) optional co-catalyst at least one selected from Ni, Cr, Mn, Mo, W, Pb, Ti, Sn, or Cu. Further, the present invention affords thin multi-walled carbon nanotube having 5˜20 nm of diameter and 100˜10,000 of aspect ratio in a high yield.

Abstract: Disclosed are a carbon nanomaterial pellet and a method for preparing same. More particularly, it relates to a carbon nanomaterial pellet having a specific size and a high apparent density prepared by a simple process using only a rotary tablet press without mixing a carbon nanomaterial powder with a solvent or an additive, which is capable of solving the powder dust problem occurring when preparing a polymer composite from a carbon nanomaterial in the form of powder, thus improving physical properties and remarkably reducing cost of packaging and transportation, and a method for preparing the carbon nanomaterial pellet from a carbon nanomaterial powder.

Abstract: The present invention relates to a catalyst for preparing a carbon nanotube having desired apparent density by controlling the adding amount of co-precipitating agent in the process of preparing a catalyst in order to obtain a catalyst having a minimized particle size. More specifically, this invention relates to a catalyst for preparing carbon nanotube having desired apparent density based upon the reverse-correlation between the amount of co-precipitating agent added in the process of preparing catalyst and the apparent density of catalyst. The carbon nanotube prepared by the catalyst having low apparent density shows excellent electrical conductivity and highly uniformed dispersion in the polymer/carbon nanotube composite.

Abstract: The present invention relates to a catalyst composition for the synthesis of thin multi-walled carbon nanotube(MWCNT). More particularly, this invention relates to a multi-component metal catalyst composition comprising i) main catalyst of Co and Al, ii) inactive support of Mg and iii) optional co-catalyst at least one selected from Ni, Cr, Mn, Mo, W, Pb, Ti, Sn, or Cu. Further, the present invention affords thin multi-walled carbon nanotube having 5˜20 nm of diameter and 100˜10,000 of aspect ratio in a high yield.

Abstract: The present invention relates to a catalyst composition for preparing carbon nanotube containing multi-component support materials of amorphous Si, Mg and Al as well as a bulk scale preparation process for preparing carbon nanotube using said catalyst composition. More specifically, this invention relates to a process for preparing carbon nanotube using the catalyst composition comprising a transition metal catalyst and support materials of amorphous Si, Mg and Al.

Abstract: The present invention relates to a process for preparing catalyst composition for the synthesis of carbon nanotube with high yields using the spray pyrolysis method. More particularly, this invention relates to a process for preparing catalyst composition for the synthesis of carbon nanotube comprising the steps of i) dissolving multi-component metal precursors of catalyst composition in de-ionized water; ii) spraying obtained catalytic metal precursor solution into the high temperature reactor by gas atomization method; iii) forming the catalyst composition powder by pyrolysis of gas atomized material; and iv) obtaining the catalyst composition powder, wherein said catalyst composition comprises i) main catalyst selected from Fe or Co, ii) Al, iii) optional co-catalyst at least one selected from Ni, Cu, Sn, Mo, Cr, Mn, V, W, Ti, Si, Zr or Y, iv) inactive support of Mg. Further, the catalyst composition prepared by this invention has a very low apparent density of 0.01˜0.

Abstract: The present invention relates to a catalyst composition for the synthesis of thin multi-walled carbon nanotube (MWCNT) and a method for manufacturing a catalyst composition. More particularly, this invention relates to a multi-component metal catalyst composition comprising i) main catalyst of Fe and Al, ii) inactive support of Mg and iii) optional co-catalyst at least one selected from Co, Ni, Cr, Mn, Mo, W, V, Sn, or Cu. Further, the present invention affords thin multi-walled carbon nanotube having 5˜20 nm of diameter and 100˜10,000 of aspect ratio in a high yield.

Abstract: The present invention relates to a catalyst for preparing a carbon nanotube having desired apparent density by controlling the adding amount of co-precipitating agent in the process of preparing a catalyst in order to obtain a catalyst having a minimized particle size. More specifically, this invention relates to a catalyst for preparing carbon nanotube having desired apparent density based upon the reverse-correlation between the amount of co-precipitating agent added in the process of preparing catalyst and the apparent density of catalyst. The carbon nanotube prepared by the catalyst having low apparent density shows excellent electrical conductivity and highly uniformed dispersion in the polymer/carbon nanotube composite.

Abstract: The present invention relates to a catalyst composition for preparing carbon nanotube containing multi-component support materials of amorphous Si, Mg and Al as well as a bulk scale preparation process for preparing carbon nanotube using said catalyst composition. More specifically, this invention relates to a process for preparing carbon nanotube using the catalyst composition comprising a transition metal catalyst and support materials of amorphous Si, Mg and Al.

Abstract: The present invention relates to a catalyst composition for the synthesis of thin multi-walled carbon nanotube (MWCNT) and a method for manufacturing a catalyst composition. More particularly, this invention relates to a multi-component metal catalyst composition comprising i) main catalyst of Fe and Al, ii) inactive support of Mg and iii) optional co-catalyst at least one selected from Co, Ni, Cr, Mn, Mo, W, V, Sn, or Cu. Further, the present invention affords thin multi-walled carbon nanotube having 5˜20 nm of diameter and 100˜10,000 of aspect ratio in a high yield.

Abstract: A photovoltaic power conditioning system and method is provided. The system includes an isolated DC/DC converter (41), a DC/AC inverter (42), and a sine filter (43). The isolated DC/DC converter (41) receives a DC voltage from a solar cell through a parallel connection structure and converts the DC voltage into another DC voltage and then outputs the converted DC voltage through a series connection structure. The DC/AC inverter (42) converts the DC voltage output from the isolated DC/DC converter into an AC voltage. The sine filter (43) performs sine filtering on the AC voltage output from the DC/AC inverter and outputs the filtered AC voltage. The system employs a topology allowing it to be responsible for part of the output capacity, thereby significantly reducing the required capacity and increasing the system efficiency, so that the system can be applied to small and large-capacity photovoltaic power generation.

Abstract: The present invention is to provide anode active material hybridized with carbon nano fibers for lithium secondary battery prepared by following steps comprising, i) dispersing the nano size metal catalyst to the surface of anode material selected from graphite, amorphous silicon or the complex of graphite and amorphous silicon; and ii) growing the carbon nano fiber by chemical vapor deposition method, wherein carbon nano fibers are grown in a vine form and surround the surface of anode active material.

Abstract: The present invention relates to a method for evaluating an initial capacity of secondary batteries and, more specifically, to a method for evaluating an initial capacity of secondary batteries that involves mathematical operation of specific internal resistance components obtained from an equivalent circuit model of an impedance spectrum measured for a short time period instead of using direct discharge characteristics, thereby allowing selection of batteries having a different initial discharge characteristic.

Abstract: The present invention relates to a method for evaluating an initial capacity of secondary batteries and, more specifically, to a method for evaluating an initial capacity of secondary batteries that involves mathematical operation of specific internal resistance components obtained from an equivalent circuit model of an impedance spectrum measured for a short time period instead of using direct discharge characteristics, thereby allowing selection of batteries having a different initial discharge characteristic.

Abstract: A method for grouping unit cells of a similar impedance spectrum uses pattern matching technology to optimize the performance of a battery pack made of primary or secondary batteries as the unit cells connected in series, in parallel or in combination of them. To make an optimal battery pack with unit cells of a different internal characteristic, the method includes measuring the impedance spectrum of the individual unit cell in a wide frequency region at the same temperature and in the same state of charge (SOC), digitizing the difference in impedance spectrum among the unit cells into a relative value using the pattern matching technology, and selecting unit cells of a most similar impedance spectrum (i.e., a smallest relative difference in impedance spectrum) to make a battery pack.

Abstract: A method for grouping unit cells of a similar impedance spectrum uses pattern matching technology to optimize the performance of a battery pack made of primary or secondary batteries as the unit cells connected in series, in parallel or in combination of them. To make an optimal battery pack with unit cells of a different internal characteristic, the method includes measuring the impedance spectrum of the individual unit cell in a wide frequency region at the same temperature and in the same state of charge (SOC), digitizing the difference in impedance spectrum among the unit cells into a relative value using the pattern matching technology, and selecting unit cells of a most similar impedance spectrum (i.e., a smallest relative difference in impedance spectrum) to make a battery pack.

Abstract: The present invention relates to a digital phase-locked loop (PLL) circuit producing an output pulse stream or clock pulses in phase with a reference clock input. The digital PLL circuit consumes reduced power during a phase error compensating operation. The digital PLL circuit of the present invention includes, inter alia, a phase comparator for detecting phase errors of an input signal and a feedback signal; a charge pump for sourcing and/or sinking current in response to control signals based on a phase error detected in the phase comparator; and a sensing circuit for detecting a simultaneous activation of the sourcing and the sinking of the charge pump and for generating a sensing signal corresponding to the simultaneous activation, whereby the phase comparator generates in response to the sensing signal the control signals to inactivate the sourcing and the sinking of the charge pump. The charge pump is also activated in response to the sensing signal.