baber/WOPTO huggingface dataset:
Patent KR-20010093915-A (KR)
Title: Method for immobilization of concentrated culture broth including whole microbial cells in capsules and a capsule prepared thereby
Inventor: CHOI SUNG BOOK
IPC: C12N1/00
Filed: 2000-04-03
Abstract: PURPOSE: A method for producing capsules immobilizing the condensed culture broth containing microorganisms with enzymes is provided, therefore the additional separation and purification processes are not required and the activity of enzymes can be maintained. CONSTITUTION: The method for producing capsules immobilizing the condensed culture broth containing microorganisms with enzymes comprises the steps of: incubating microorganisms to accumulate enzymes in a medium; condensing the culture broth containing microorganisms and enzymes under reduced pressure to prepare condensed culture broth; and immobilizing the condensed culture broth to produce capsules. In the step of producing the capsule, it particularly comprises the steps of: mixing the condensed culture broth with calcium chloride solution in a same volume ratio; adding xanthan gum into the mixture; and adding droplet of the mixture into sodium alginate solution containing surfactant.
Patent KR-20010096885-A (KR)
Title: 헤드 마운트 디스플레이용 광학 시스템
Inventor: PARK JONG BAE
IPC: G02B27/01
Filed: 2000-04-15
Abstract: 본 발명은 헤드 마운트 디스플레이에 관한 것으로, 본 발명은 광원과; 광원의 광선을 분산시키는 조명 분산부와; 조명 분산부로부터 출사되는 광선을 분리하는 편광 분할기와; 편광 분할기로부터 출사되는 광선에 의해 화상을 표시하며, 착용자의 동공거리에 따라 간격조절이 가능한 반사형 액정 스크린과; 편광 분할기의 전방에 배치되어 액정 스크린의 화상을 확대시키는 접안렌즈와; 접안레즈의 전방에 배치되어 접안렌즈로부터 출사되는 광선속을 부분적으로 차단하는 조리개와; 조리개의 전방에 배치되는 보호경을 포함하는 것을 특징으로 한다. 이와 같은 본 발명은 초점이 다른 부위는 볼 수 없도록 접안렌즈로부터 출사되는 광선을 선택적으로 차단함으로써 착용자에게 보다 선명하고 깨끗한 화상을 제공할 수 있는 효과를 갖는다.
Patent KR-20010097184-A (KR)
Title: 세탁기의 하부베이스
Inventor: KIM BYEONG TAE
IPC: D06F39/14
Filed: 2000-04-20
Abstract: 본 발명은 세탁기의 하부베이스에 관한 것으로서, 세탁기의 아웃케이스 하단에 결합되는 하부베이스에 있어서, 아웃케이스의 전면 양측 모서리부의 하단과 전면 하단 전체에 걸쳐서 결합되는 전방베이스와, 상기 아웃케이스의 후면 양측 모서리부의 하단에 각각 결합되는 후방베이스로 별도 구성되어 아웃케이스의 하단 전면 및 하단 사측 모서리부만을 부분적으로 지지하도록 함과 아울러 상기 전방베이스 상에는 아웃케이스의 내면을 외측을 향하여 탄력적으로 지지할 수 있는 지지부재를 설치하여 아웃케이스와 전방베이스의 결합부위에 틈새가 발생하지 않도록 보다 견고하게 결합시킬 수 있으며, 하부베이스의 생산원가를 낮출 수 있도록 한 것이다.
Patent KR-20010097443-A (KR)
Inventor: AN KWANG SU
Filed: 2000-04-22
Abstract: 본 발명은 인터넷 상에서의 광고방법에 관한 것으로서, 보다 상세하게는 오타가 삽이된 광고문안에 대해 사용자가 맞춤법 교정을 하도록 하여 광고를 전달할 수 있는 맞춤법 교정을 이용한 광고방법 및 상기 방법을 실현시키기 위한 프로그램을 기록한 컴퓨터로 읽을 수 있는 기록매체에 관한 것이다. 
     본 발명의 목적은 사용자가 광고를 클릭하면 오타가 삽입된 광고문구를 전송받아 수정함으로서 포인트점수를 제공받아 사용자에게 흥미를 유발하여 광고 효과를 극대화할 수 있는 광고방법을 제공함에 있다. 
     상기한 목적을 달성하기 위한 본 발명의 방법은, 인터넷 상에서 웹서버에 의한 광고방법에 있어서, 상기 웹서버에 오타가 삽입된 광고문안의 문제은행데이타베이스와 광고 데이타베이스를 구축하는 단계와, 사용자로부터의 광고클릭 신호에 의해 상기 문제은행 데이타베이스에서 오타가 삽입된 광고문안을 상기 사용자의 웹브라우저에 출력하는 단계와, 상기 사용자가 오타를 수정한 광고문안을 상기 웹서버에 전송하는 단계와, 상기 전송된 오타를 수정한 광고문안에 대해 포인트를 제공하고 정산하는 단계로 이루어짐을 특징으로 한다. 
     또한 바람직하게는 상기 포인트가 소정점수 이상인 사용자들에 대해 오타 수정대회를 실시하는 단계를 더 포함하여 이루어지는 것을 특징으로 한다. 
     또한 본 발명은 마이크로 프로세서가 내장된 인터넷 상의 웹서버를 구비한 광고시스템에 있어서, 상기 웹서버에 오타가 삽입된 광고문안의 문제은행데이타베이스와 광고 데이타베이스를 구축하는 기능과, 사용자로부터의 광고클릭 신호에 의해 상기 문제은행 데이타베이스에서 오타가 삽입된 광고문안을 상기 사용자의 웹브라우저에 출력하는 기능과, 상기 사용자가 오타를 수정한 광고문안을 상기 웹서버에 전송하는 기능과, 상기 전송된 오타를 수정한 광고문안에 대해 포인트를 제공하고 정산하는 기능을 실현시키기 위한 프로그램을 기록한 컴퓨터로 읽을 수 있는 기록매체를 포함한다.
Patent KR-20010112864-A (KR)
Title: Controller for Gas Lamp
Inventor: KIM BYEONG GWAN
IPC: H05B41/288
Filed: 2000-06-15
Abstract: An oriented co-extruded film suitable for use as a window film for mailing envelopes, having a polyolefin layer and a non-glossy surface layer of polystyrene.
Patent KR-20010049571-A (KR)
Title: Film multipackage
Inventor: MARCO LESLIE S
IPC: B65D71/12
Filed: 2000-06-19
Abstract: PURPOSE: Film multipackage is provided, which unitizes a plurality of containers with a retainer sheet integrated with a carrier sleeve. CONSTITUTION: The retainer sheet comprises a plurality of container receiving openings for engaging a top portion of a group of containers of the plurality of containers and two partial container receiving openings for partially engaging a top portion of two additional containers of the plurality of containers. The carrier sleeve surrounds the plurality of containers and a handle is positioned over a center row of containers. A package including containers comprises two layers of containers within the film sleeve.
Patent KR-20010113313-A (KR)
Inventor: NAM GYU HWAN
IPC: B65H23/185
Filed: 2000-06-19
Abstract: 본 발명은 언 와인딩 머신의 유압식 구동장치에 관한 것으로, 구동축에 연결되는 유압 모터와, 내부에 작동 유체가 채워지고 상기 유압 모터와 입력 라인, 출력 라인 및 드레인 라인으로 연결되고 작동 유체에 유압을 발생시키는 유압 밸브 유닛과, 상기 입력 라인 및 출력 라인의 작동 유체 이동 경로를 변경시키는 3방향 전환용 솔레노이드 밸브와, 상기 입력 라인 및 출력 라인의 소정 부위에 각각 설치되는 체크 밸브 및 제1 릴리이프 밸브로 이루어져 브레이크 기능을 수행하는 브레이크 밸브와, 상기 브레이크 밸브의 제1 릴리이프 밸브로 연결 설치되는 2방향 전환용 솔레노이드 밸브 및 제2 릴리이프 밸브로 이루어져 백 텐션을 조절하는 적어도 1 이상의 리모트 콘트롤 밸브를 포함하여 구성한다. 
     상기와 같은 본 발명에 따르면, 언 와인딩 릴의 백 텐션을 자유롭게 다단계로 임의로 조절하여, 보다 안정된 백 텐션을 구현하며, 또한 구조를 보다 단순화하여 생산원가 절감에 기여함과 아울러 유지 비용을 절감시키고, 뿐만 아니라, 기존의 기계식 에어 클러치 및 에어 브레이크의 사용을 배제하여. 그에 따른 각종 폐해를 해소하며, 작업장 환경을 크게 개선하여 작업자의 건강을 증진시키고, 작업 능률의 향상에도 기여한다.
Patent KR-20020000182-A (KR)
Title: Pad for automobile engine hood
Inventor: KIM JAE YEOL
IPC: B62D25/08
Filed: 2000-06-22
Abstract: PURPOSE: A vehicle engine hood pad is provided to obtain superior sound absorption effect by stacking a plurality of primary products in the shape of mat composed of different thickness or density. CONSTITUTION: A vehicle engine hood pad is manufactured by the steps of mixing polyethylene terephthalate fiber with low melting polyethylene terephthalate fiber, thermally fusing a web state material subject to carding to the mixed polyester fiber for obtaining primary products in the mat state, stacking the primary products in a multi-step structure, melting the low melting fiber to be fused between fibers, and carrying out trimming after cold-rolling, wherein fiber yarns composing the mat are different in density or thickness.
Patent KR-20020000274-A (KR)
Title: Novel compound from Chimaphila umbellata and pharmaceutical compositions thereof
Inventor: HWANG GWI SEO
IPC: C07H15/20
Filed: 2000-06-22
Abstract: PURPOSE: A naphthalene compound isolated from Chimaphila umbellata and a pharmaceutical composition containing the same compounds as an effective component are provided, thereby the compound can be effectively used in prevention and treatment of osteoporosis. CONSTITUTION: The naphthalene compound isolated from Chimaphila umbellata or salt thereof is represented by formula(1), in which R is hydrogen or C1 to C4 alkyl; the naphthalene compound is 3,6-dimethyl-1-hydroxynaphthalene- 4-glucopyranoside isolated from Chimaphila umbellata by extracting Chimaphila umbellata with an organic solvent selected from lower alcohol, chloroform, ethylacetate and the mixture thereof and subjecting the extract to chromatography. The pharmaceutical composition useful for the prevention and treatment of osteoporosis contains the naphthalene compounds as an active ingredient.
Patent KR-20020001957-A (KR)
Title: E-comerce system and method thereof
Inventor: KIM HYEONG UK
Filed: 2000-06-22
Abstract: PURPOSE: An electronic business system and a method therefore are provided to make a purchase continually participate in purchasing products by purchasing power from simple curiosity and various product purchase and enable the purchaser to buy general products at low costs, thereby increasing selling. CONSTITUTION: If a terminal of a purchaser requests unit purchase through a network and inputs unit purchasing money accordingly, reserved money to the corresponding product is increased as much as unit purchasing money. In case that the increased product reversed money is coincide with a contract standard price of the corresponding or the product reserved money exceeds the contract standard price, a system selects one purchaser in a plurality of purchasers requested unit purchase to the product, so that the system grants a purchase right to purchase the products with the requested unit purchasing money.
Patent KR-20020004166-A (KR)
Title: Kindergarten education method on line
Inventor: PARK JONG WON
Filed: 2000-07-03
Abstract: PURPOSE: A preschool learning method using online is provided to reduce special and temporal limits in receiving/giving an education through the Internet. CONSTITUTION: An operator confirms the progress of class work of a member if the user is a member. Next, the member receives an education with class work suitable to the learning level of the member by the operator. Then, the operator evaluates the learning progress of the member. Finally, the operator guides and evaluates the learning contents of the member. In addition, the operator provides information to the member while confirming the learning progress.
Patent KR-20020006934-A (KR)
Title: Fabrication method of a metal mask
Inventor: LEE JU HUN
IPC: G02B6/10
Filed: 2000-07-14
Abstract: PURPOSE: A method for manufacturing a metal mask is provided to prevent bull's eye effect and contamination and to achieve narrow-width patterning by removing a metal layer deposited on the sidewall of a photoresist mask using a lift-off process. CONSTITUTION: A silica layer is formed on a silicon substrate(11). A photoresist is formed on the silica layer by spin coating process. The photoresist is patterned to form a photoresist mask. On the silica layer and photoresist mask, a metal layer is formed by sputtering process. The metal layer deposited on the sidewall of the photoresist mask is removed by a wet etching. The photoresist mask is removed with an etchant of photoresist to form a metal mask(17) for forming silica optical waveguide. The silica layer is formed by a flame hydrolysis deposition process.
Patent KR-20000072062-A (KR)
Inventor: PARK DONG SHIK
IPC: A47J31/00
Filed: 2000-07-19
Abstract: PURPOSE: An apparatus of preparing red ginseng and red ginseng juice is provided which can not only prepare easily the red ginseng and the juice thereof at home, but prevent basic components of the red ginseng from evaporating as vapor. CONSTITUTION: An apparatus of preparing red ginseng and red ginseng juice comprises a heating vessel(12) having an inner bath(10) which is provided predetermined amount of water into the upper part of the inner side; a heating mean(14) for heating water, optionally provided into the inner bath(12) depending on the supply of power, if desired; a sensor for sensing the temperature of the inner bath(10) and outputting the sensed temperature; a control part(20) for controlling selectively the heating means(14); a water bath(30) equipped with a first silicone packing(34) in the part of being contacted with the heating vessel(12); a support(40) for green ginseng; and a condensing vessel(50) equipped with a second silicone packing(56) in the part of being contacted with the water bath(30).
Patent KR-20010076162-A (KR)
Title: Magnetic disk drive having characteristic cable array and electronic device using thereof
Inventor: HANAZAWA SHIGEYUKI
IPC: G11B25/04
Filed: 2000-07-19
Abstract: PURPOSE: A magnetic disk drive having characteristics in wiring of a cable is provided to solve the problem that the reactive force of a FPC(Flexible Printed Circuit) cable exerts a bad influence when supporting a HDA(Hard Disk Assembly). CONSTITUTION: The center of gravity of an HDA is rotatably supported as the center of rotation when performing the tight fixing of the HDA in the translation direction and the loose fixing in the rotating direction. However, in case of using an HDA for general-purpose, the HDA is placed so that the bending portion of a cable(301) may come to the point coincident with the center of rotation or near the center of gravity. Thereby, the hardness of the FPC cable may not affect the rotatable supporting mechanism. The occurrence of torque acting as an obstruct to the free rotation of the HDA can be minimized. The HDA for general-purpose can be mounted and the technique of the loose fixing can be generalized. As a result, the mounting of a magnetic disk drive to a portable or moving body can be generalized.
Patent KR-20010066942-A (KR)
Title: Yarn treatment jet
Inventor: HINCHLIFFE MALCOLM GEOFFREY
IPC: D02J1/00
Filed: 2000-07-20
Abstract: PURPOSE: A yarn treatment jet is provided, which relates to air jets for treating textile yarns, in particular for texturing multifilament yarns by subjecting the filaments to a turbulent airflow to increase the bulk of the yarns. CONSTITUTION: The yarn treatment jet(20) has a venturi member(11) with a venturi shaped bore(12), and an inlet member(14) with a yarn passage(15) therethrough located in the mouth(13) of the bore(12), in which the inlet member(14) is in contact with the mouth(13) of the bore(12) to locate the inlet member(14) positively relative to the venturi member(11) and is configured to provide a passage(18) for air into the venturi bore(12) between the inlet member(14) and the venturi member(11). The inlet member may be formed of a core and a needle so that to change the configuration of the air passage(18) only the core need to be changed. The air passage(18) is formed by one or more grooves(22) or bores in the inlet member(14) or core.
Patent KR-20020016236-A (KR)
Title: Micro mirror actuator and method for producing the same
Inventor: KWON SUN CHEOL
IPC: G02B26/08
Filed: 2000-08-25
Abstract: PURPOSE: An apparatus for driving a micro mirror and a fabrication method thereof are provided, which reduces a size of a device and makes a rotation driving easily. CONSTITUTION: The apparatus comprises a substrate(31), a driving coil(30), a magnetic body(32), an anchor(35), a bending spring(34) and a micro mirror(33). All of the above components are formed on one substrate using a micro machining technology including a plating, a sputtering and a photo lithography process. The magnetic body is attached on a bottom of the micro mirror, and the bending spring is attached on both sides of the micro mirror. And the coil is formed spirally around the micro mirror. The bending spring is supported by the anchor formed on the substrate, and therefore the micro mirror is supported by being separated from the substrate by the anchor by intermediating the anchor. The micro mirror is formed with an aluminum having a high reflectivity and a low cost, and the magnetic body is formed to coincide with an area of the micro mirror with a permalloy.
Patent KR-20020019824-A (KR)
Title: Ticketing service system and method by using mobile communication terminal
Inventor: CHO GYU SEOK
IPC: H04B7/26
Filed: 2000-09-07
Abstract: PURPOSE: A ticketing service system using a mobile communication terminal and a method thereof are provided to issue various tickets on line, thereby using the mobile communication terminal as a substantial ticket. CONSTITUTION: A service user connects to a service server by using a personal computer or a mobile communication terminal through a data communication network(S302). The service user selects a ticket purchase menu for requesting service and the service server provides a screen for selecting an affiliated concern(S303-S304). If the user selects the desired affiliated concern, the service server provides ticket information of the corresponding concern in detail(S305-S306). The user inputs information of the ticket to be purchased, and the service server compares ticket information input by the user with ticket information stored at a database so that the service server confirms whether the corresponding ticket is available to be issued(S307-S308). If available, the service server requests settlement information and specific information related to the terminal of the user(S310). If not available, the server notifies that the ticket cannot be issued(S309). After information input of the user, the server performs a credit inquiry for determining transaction permit(S311-S312). The server transmits the ticket in the form of computerized data to the terminal(S313). If the transaction is not permitted, the server transmits error data to the terminal in case that the transaction is not permitted repeatedly over the predetermined frequency(S314-S315).
Patent KR-20020027124-A (KR)
Title: Ferroelectrics - Ferromagnetics Composites and Fabricating Method Thereof
Inventor: JE HAE JUN
IPC: H01F1/34
Filed: 2000-10-07
Abstract: PURPOSE: Provided are a complex of ferroelectrics and ferromagnetics which has both ferroelectricity of the ferroelectrics and ferromagnetism of the ferromagnetics and can be used as memory elements, and etc, and a method for producing the same. CONSTITUTION: The method comprises the steps of (i) synthesizing ferroelectric ceramics, (ii) crushing the ferroelectric ceramics into the powder, (iii) synthesizing ferromagnetic ceramics, (iv) crushing the ferromagnetic ceramics into the powder, (v) mixing the ferroelectric ceramics power and the ferromagnetic ceramics powder, and (vi) compression molding the mixture.
Patent KR-20010040069-A (KR)
Title: Method and apparatus for producing reduced metal
Inventor: TATEISHI MASATAKA
IPC: C22B5/10
Filed: 2000-10-12
Abstract: PURPOSE: Provided is equipment for manufacturing reduced iron, in which heat-storage type burners are used in a reducing furnace for manufacturing reduced iron by heating and reducing agglomerated material including carbonaceous material. CONSTITUTION: In the reduced iron manufacturing equipment employing the reducing furnace and the heat-storage type burners as the heating device, combustion gas of the heat-storage type burner is in an oxidizing atmosphere and the atmosphere covering the agglomerated material is a reducing one and the heat-storage type burners are set mutually inward in the horizontal direction so that the combustion gas of a suction/exhaust part of the one side of heat storage type burner can release the heat in the suction/exhaust part of the other side of heat-storage type burner and then be exhausted therefrom, and the setting position of the heat storage type burners are the latter half part of the reducing process and at the front part thereof, a gas exhaust part is arranged. Further, the reduce iron manufacturing equipment is provided with the gas exhaust part at the rear part of a process, in which the surface temperature of the agglomerated material including the carbonaceous material is lower than 1,250 deg.C at the setting position of the heat-storage type burner. Furthermore, in the reduced iron manufacturing equipment, the storage material in the heat-storage type burner is iron ore pellet.
Patent KR-20010060225-A (KR)
Inventor: YAMASHITA TAKAHIRO
IPC: H02J7/04
Filed: 2000-10-31
Abstract: PURPOSE: To fully charge an overdischarged battery by quickly charging it accurately. CONSTITUTION: In a quick charging method, it is judged to be full charge by detecting the peak voltage of the voltage of a secondary battery 1 or the drop of ΔV. When the charge is started, the charge start voltage of the battery is detected. A battery, where the charge start voltage is higher than the set voltage, is charged with a rated quick charge current. A battery where the charge start voltage is lower than the set voltage, is charged quickly with a limited quick charge current lower than the rated quick charge current.
Patent KR-20020038360-A (KR)
Title: Shifting apparatus of manual transmission
Inventor: HUH JIN UK
IPC: F16H63/36
Filed: 2000-11-17
Abstract: PURPOSE: A device for operating speed change of a manual transmission is provided to prevent wear and vibration of a shift fork and to improve life time and noise of the transmission by having a structure to simultaneously control axial behavior and behavior of rotational direction. CONSTITUTION: A device for operating speed change of a manual transmission includes a shift rail(51) forming plural grooves(53) according to the shifting level, and a poppet ball, inserted in the groove, controlling axial behavior of the shift rail. The grooves forms walls controlling movement of the poppet ball(55) at both ends of the rotational direction of the shift rail to control behavior of the rotational direction of the shift rail. The grooves are rectangular shape. The axial behavior and the behavior of rotational direction are controlled and the contacting of a shift fork(61) and a sleeve(63) is prevented, and therefore wear of the shift fork is prevented.
Patent KR-20020040045-A (KR)
Inventor: LEE CHI U
IPC: H02K15/02
Filed: 2000-11-23
Abstract: PURPOSE: A manufacturing method of a rotor core assembly is provided to improve efficiency of a motor and productivity by automatically stacking core pieces and removing caulking. CONSTITUTION: For manufacturing a rotor core assembly, core pieces(51) are formed to have their temporal inner diameters(ID') that are smaller than their final diameters(ID). The core pieces(51) are automatically stacked by coupling caulking parts(53) inside the final diameters(ID) of the core pieces(51) to form a stack(55). After stacking the core pieces(51), an aluminium bar and end rings are formed inside slots(57) of the stack(55) by aluminium diecasting process. Then, the temporal inner diameters(ID') are processed to the final diameters(ID) to remove the caulking part(53) and the outer diameter of the stack(55) is processed to complete the rotor core assembly. Remove of the caulking part(53) from a yoke of the core pieces(51) eliminates deterioration of motor efficiency.
Patent KR-20020041069-A (KR)
Inventor: NAM MIN U
IPC: G01N3/40
Filed: 2000-11-27
Abstract: PURPOSE: An automatic hardness tester is provided to achieve improved quality and reduce reject ratio by easily and accurately measuring the degree of hardness of the sample. CONSTITUTION: An automatic hardness tester comprises a data processing unit(10) for transmitting the test instructing information selected by a worker to a control unit(12), calculating the value of hardness and displaying the value; the control unit connected to the data processing unit, and which controls a facility of transferring and evaluating a sample(1) in accordance with the signal output from the data processing unit; a sample load unit(14) having a sample scrap box(18) where samples are loaded, and a sensor installed in the lower portion of the sample scrap box so as to sense the existence of the sample and inform the sensed result to the data processing unit; a vertical sample transfer unit(22) having a sample conveying cylinder(28), an adsorption pad arranged underneath an elevating member, and a vacuum breaking cylinder connected to the elevating member; a horizontal sample transfer unit(36) arranged onto a transfer table(38), and which has a grip cylinder(42) for gripping the sample through an air; an anvil unit(44) having an anvil(46), a sensor(47) for sensing the existence of sample on the anvil, and a clamp drive cylinder(50) for elevating a clamp(48) when the sample is positioned onto the anvil; a hardness measuring unit(52) for measuring hardness of the sample and transmitting the value obtained from the measurement to the data processing unit; and a scrap box(58) for loading the sample after completion of measurement.
Patent KR-20020044256-A (KR)
Title: White Rice Husk Ash filled Tread rubber composition for Truck and Bus tire
Inventor: CHOI SEONG SIN
IPC: C08L7/00
Filed: 2000-12-05
Abstract: PURPOSE: Provided is an eco-friendly tread rubber composition for truck and bus tires having a low gasoline mileage, and improved chipping and cutting property by applying white rice husk ash together with carbon black, as fillers, to a rubber composition. CONSTITUTION: The tread rubber composition for truck and bus tires comprises 100 parts by weight of rubber material, 15-60 parts by weight of carbon black, and 5-20 parts by weight of white rice husk ash. In the composition, compounding ratio of carbon black/white rice husk ash is 10/1 - 3/1. The rubber material is a natural rubber, or a mixture produced by mixing styrene-butadiene rubber, polyisoprene rubber or butadiene rubber into 60% or more of natural rubber. The white rice husk ash comprises 94-99% of SiO2, 0.5-1.5% of CaO, 0.1-0.5% of MgO, 0.1-0.5% of Fe2O3, and 5% or less of carbide components, and has a particle size of 10 micrometers or less.