• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.4 s.50
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• pp.77-84
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• 2006

Recently, as large structures such as high-rise building and long span bridge become lighter and more flexible, the necessity of structural control for reducing excessive dynamic response due to seismic excitation is increased. In this study, a semi-active base isolation system using Magneto-Sensitive (MS) rubbers is proposed to effectively protect structures against earthquakes. MS Rubber is a class of smart controllable materials whose mechanical properties change instantly by the application of a magnetic field. To demonstrate the performance of this device, the MS Rubber isolation system is compared to Lead-Rubber Bearing (LRB) isolation systems and judged based on computed responses to several historical earthquakes. The MS Rubber isolation system is shown to achieve notable decreases in base drifts over comparable passive systems with no accompanying increase in base shears or in accelerations imparted to the superstructure. The proposed MS Rubber system is shown to perform better than the passive isolation system.

• Journal of the Korean Magnetics Society
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• v.8 no.5
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• pp.255-260
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• 1998

Fabrication condition and magnetic properties of ultrathin Co-based amorphous alloy have been investigated. When the ejection gas pressure was lower than 0.05 kgf/$\textrm{cm}^2$ at the roll speed of 55 m/s, ultrathin ribbons with the thickness less than 10 ${\mu}{\textrm}{m}$ were successfully obtained. The ribbon thickness decreased linearly with the decrease in ejection pressure. Moreover the significant decrease in ribbon width was accompanied with the decrease of thickness in the range of ejection pressure to form an ultrathin ribbon. This behavior was attributed to the decrease of effective ejection pressure in the both end-sides of rectangular nozzle due to the larger friction between molten metal and nozzle wall. The effective permeability at low frequency (1 kHz) decreased largely with the decrease in ribbon thickness, while the coercive force increased with the thickness decrease. It was considered that these behaviors were due to the enhancement of surface effect leading to the suppression of wall motion. However effective permeability at high frequency (1 MHz) increased with the decrease in ribbon thickness, and this was ascribed to the easier magnetization rotation owing to the reduction of eddy current.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.9
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• pp.72-80
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• 2009

When the magnet wheel rotates over a conducting plate, it generates the traction torque as well as the repulsive force on the conducting plate. Partially-cut traction torque results in the linear force into the tangential direction. To cut the traction torque, the concept of magnetic shield is introduced. The direction change of the linear force is realized varying the shielded area of magnetic field. That is, the tangential direction of non-shielded open area becomes the direction of the linear thrust force. Specially a shape of permanent magnets composing the magnet wheel leads to various pattern of magnetic forces. So, to enlarge the resulting force density and compensate its servo property a few simulations are performed under various conditions such as repeated pattern, pole number, radial width of permanent magnets, including shape of open area. The theoretical model of the magnet wheel is derived using air-gap field analysis of linear induction motor, compared with test result and the sensitivity analysis for its parameter change is performed using common tool; MAXWELL. Using two-axial wheel set-up, the tracking motion is tested for a copper plate with its normal motion constrained and its result is given. In conclusion, it is estimated that the magnet wheel using partial shield can be applied to a noncontact conveyance of the conducting plate.

• Journal of Korean Medical classics
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• v.19 no.4
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• pp.12-26
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• 2006

유하간(劉河間), 주단계적학설전파이후(朱丹溪的학說전播以后), 인위명대모사의가용약적시후편중고한(因위明代某些의家用葯的時候偏重苦寒), 소이도치료상비위이극벌진양적폐두(所以도致了상脾胃而克伐眞陽的弊두). 종이위료교정착오(종而위了교正착오), 형성료주장온보적온보학파(形成了主張溫보的溫보學派). 설기(설己), 손일규(孫一圭), 張景岳等溫보학파강조주재생명적비위(張景岳等溫보學派强凋主宰生命的脾胃), 신명양기(腎命陽氣), 재변증론치방면입족우선(在辨證論治方面立足于先), 후천(後天), 중시비여신(重視脾與腎), 선용료감온적약물(善用了甘溫的藥物). 저대우교정착오기착극대적작용(저대于교正錯오起着極大的作用), 동시논증(同時논증), 이론전개상비위여신명이주제공탁료(理론展개上脾胃여腎命以主제공托了), 우기후자가심료명문학설적연구(尤其后者加深了命門학설的硏究). 장경악활동적명대시이주자학위국책적(張景岳活동的明代是以朱子學위國策的), 구비사변성적철(具비思辨性的哲) 학배영상(학背영上), 추상(推想)"리(理)"이발휘의(而발휘의) 학이론(학理론). 우시저시기의가문입족우(于是저시期의家門立足于) "황제내경(黃帝內經)" 여연기론진행료기초이론화임상연구(여연氣論진行了基초理론和임床硏究), 경악통과편찬(景岳通과編찬) "내경(內經)"이저작(而著作)"류경(類經)"등(等), 근거자기적임상실험(根据自己的임床실험), 제출료온보학설(提出了溫보학설). 타쟁론적초점시자기제출적(他爭론的焦点是自己提出的)"음부족론(음不足론)". 침대전현적쟁론상(침대前현的爭론上), 경악이하간여범계위대상경(岳以河間여凡溪위대象). "경악전서(景岳全書)" 지운(之云): "양자유하간출(襄自劉河間出), 이서화입론(以署火立論), 전용한량벌차양기(專用寒凉伐此陽氣), 기해이심(其害已甚), 뢰동원선생비위지화필수온양(賴東垣先生脾胃之火必須溫養), 연상미능진척일편지류(然尙未能盡斥一偏之謬), 이단계복출(而丹溪復出), 우입음허화동지론(又立陰虛火動之論) ...... 한량지폐우복성행(寒凉之弊又復盛行), 부선수기해자기거이불반(夫先受其害者旣去而不返), 후습이용자유미이불오(後習而用者猶迷而不悟)", 지분료하간여단계시(指분了河間여丹溪是)"헌기지마(軒岐之魔)". 저사주장현출독특적유해저(些主장현出독特的유解), 이대후대학설발전적봉헌(以대后代학설발展的奉헌). 경악침대단계적"양상유여(景岳침대丹溪的)"양상유여(陽常有餘), 음상부족(陰常不足)", "기유여변시화(氣有餘便是火)", 설성(설成)"양비유여(陽非有餘), 진양부족(眞陽不足)", "기부족변시한(氣不足便是寒)", "상화부시사화(相火不是邪火)", 대단계학설견지료비판적입장(대丹溪학설堅持了批判的立장). 단계제출(丹溪提出)"양음설(養陰說)"이수립음허화왕적병기이론(而수立陰虛火旺的病機理론), 타적(他的)'양유여음부족론(陽有餘陰不足論)'상(上), '음(陰)'주요지생식물질(主要指生殖物질), "양(陽)"지정욕(指情欲). 가시중심사상시강조생리적양생(可是中心思想是强조生理的양생), 몰수립실제(沒수立실제)'음허화왕(陰虛火旺)'적병기(的病機). 취시장경악실재완성료저사병기(就是張景岳실在完成了저些病機). 경악재(景岳在) "진음론(眞陰論)" '장형질설성진양적상(將形질설成眞陽的象), 이명문위기(以命문위其)', 용(用)"개부족(皆不足)"해석질병(解석질病), 이익화(以益火) 장수이론위치법(장水理론위治法). 이차제조좌우귀환(而且制造左右歸丸) 음이귀납료치료방법(飮以귀納了治료方法), 발휘진음(발휘眞陰), 진양학설이구조유계통적이론(眞陽學說而구造有系統的理론). 저양위의가적쟁론핵심리유상화론(저兩位의家的爭론核心里有相火論), 논자상교연구타문적이론이보고기결과(논者相교硏究他문的理론而보告其結果).

• Economic and Environmental Geology
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• v.34 no.4
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• pp.355-373
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• 2001

Palaeomagnesim of Paleozoic Tuwibong Type Sequence in Yemi area was studied with a total of 256 core-samples collected from 23 sites. The study area (geographical coordinates: 37.l8$^{\circ}$N, l28.610E) is located between Taebaek and Yongwol belonging to the northeastern part of the Okchon Belt. Thermal cleaning was a most effective method to extract stable characteristic remanent magnetization (ChRM) direction, even though AF cleaning also worked on some specimens. Mean ChRM direction of the Cambrian Hwajol Formation was different from the present-day field direction and showed maximum clustering (max. k value) at 100% bedding-tilt correction. However, it could not pass the fold test. Ordovician Makkol and Kosong Limestones as well as Permian Sadong and Kobangsan Formations have very weak NRM, and were remagnetized into the present-day field direction. ChRM directions from the Carboniferous Hongjom Formation passed both fold and reversal tests. IRM experiments and blocking temperature spectrum indicate that both magnetite and haematite are carrier of the primary magnetization. Palaeomagnetic pole position from the Carboniferous Hongjom Formation is very similar to that of contemporary North China Block (NCB) suggesting that the study area was a part of, or located very near to, the NCB during Carboniferous.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.85-92
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• 2008

National Oceanographic Research Institute is carrying out an oceanographic survey for the entire sea areas around Korean Peninsula annually starting with the East Sea from 1996 by establishing a national oceanographic basic map survey plan for the sea areas under the jurisdiction of Korea, so this paper used the oceanographic geomagnetism data measured at the southern area of the Yellow Sea using 'Hae Yang 2000' in 1999, aiming at clarifying the cause of geomagnetic abnormality zone during the course of treating and analyzing the geomagnetic data. For treatment of magnetic data, we obtained electromagnetic force values and geomagnetic abnormality values around the investigated sea area through a process of searching and removal of bad data, correction of sensor positions, correction of magnetic field effects around the hull, correction of diurnal variation, normal correction, correction of cross point errors, etc. The electromagnetic force distribution around the investigated sea area was $49000\;{\sim}\;51600\;nT$, which is judged to be within the normal electromagnetic force intensity distribution range around the Yellow Sea. The isodynamic lines are distributed in Northeast-Southwest direction, and electromagnetic force values are increasing toward the northwest. The result of comparing the magnetic abnormality around the sea area among $124^{\circ}$ 49' 48" E, $35^{\circ}$ 10' 48" N $\sim$ $125^{\circ}$ 7' 48" E, and $35^{\circ}$ 33' 00" N sections with the elastic wave cross section and the result of modeling coincide well with the underground geological structure clarified from the existing elastic wave survey cross section. Therefore, it is judged that the distribution of magnetic force abnormality generally shows the effect pursuant to the distribution of the sedimentary basins in the Tertiary period and the bedrocks in the Cretaceous period which are well developed in the bottom of the sea.

• Journal of Biomedical Engineering Research
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• v.23 no.3
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• pp.227-233
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• 2002

The IME(implantable middle ear) system is Promising due to its ability to free from sound feedback and Produce a good sound quality and intelligibility with low distortion even if it is operated with high gain for severe hearing impaired. The differential electromagnetic vibration transducer. which was developed for using in IME system and has two small magnets attached the same Pole facing in the coil. is not influenced by environmental external magnetic field. Besides, it has high vibration efficiency and good frequency response characteristics. In this Paper, using acoustic model of the transducer and ear model of normal Person. the signal transfer characteristics of the IME system are analyzed and investigated From the differences of the characteristics between normal ear and the IME system, it is Possible that design of the IME system that have the signal transfer characteristics similar to normal person's ear.

• Journal of Sensor Science and Technology
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• v.11 no.3
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• pp.171-182
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• 2002

The differential electromagnetic transducer for IME(implantable middle ear) system, which have two small permanent magnets glued with the same pole facing each other in the coil, has high vibration efficiency and does not influenced by external magnetic field. In this paper, using finite element method, highly efficient structure of the transducer was proposed and vibration force of the transducer was calculated by electromagnetic theory. And the necessary vibration force of transducer to transmit the sound signal to inner ear when the transducer is attached at stapes was calculated and the design parameters of the transducer were investigated. Using the parameters, the differential electromagnetic transducer was manufactured in small size to implant in confined human middle ear. And it was examined by unloaded and loaded vibration experiment using temporal bone sampled from cadaver.

• Ocean and Polar Research
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• v.26 no.4
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• pp.559-565
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• 2004

Total magnetic field measurements were performed to study paleomagnetism of three seamounts (OSM7, OSM8-1, and OSM8-2) to the northwest of the Marshall Islands in the western Pacific. The study area is located at the Ogasawara Fracture Zone which is a boundary between the Pigafetta and East Mariana basins. The magnetic parameters and paleopoles of three seamounts were derived from inversion of the measured magnetic field. The goodness-of-fit ratio of OSM7 is too low to be included to the estimation of parameters. The complex magnetic anomalies of center, scarcity of flank rift zones and steep slope at OSM7 suggest that the multiple intrusions of magma converge into the center of volcanic edifice. Inclination calculated from the magnetic anomalies of OSM8-1 and OSM8-2 is $-41.2^{\circ}$, and the paleolatitude calculated from the inclination is $23.6^{\circ}S$. The corresponding paleopoles for OSM8-1 and OSM8-2 are $(24^{\circ}42'W,\;48^{\circ}54'N)\;and\;(18^{\circ}18'W,\;48^{\circ}30'N)$, respectively. In comparison with the apparent polar wander path (APWP) of the Pacific plate, the paleopoles are close to 129-Ma pole. The paleopoles and paleolatitudes of OSM8-1 and OSM8-2 suggest that they were formed at similar time and location. The seamounts have drifted northward about $41^{\circ}$ from the paleolatitude to present latitude of seamounts.

• Journal of the Korean Magnetics Society
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• v.14 no.3
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• pp.109-113
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• 2004

GMR isolator was modeled using a Wheatstone bridge which is profitable for transmitting rectangular wave digital data, and the output voltage characteristics in relation to the input current were investigated in time domain. GMR isolator modeling was divided into two parts, namely magnetic and electric parts. The flow chart of the modeling was drawn in which measured MR curve of the spin valves were incorporated to obtain the electrical voltage output. For magnetic modeling, 3-dimensional model of planar coil was analyzed by FEM method to obtain the magnetic field strength corresponding to the input current. For electric modeling, resistance, inductance and capacitance of the planar coil were calculated and magnetic field waveform was obtained corresponding to the coil current waveform in time domain. Finally, MR-H curves of spin valves and the magnetic field waveform at the spin valves were composited to obtain the output voltage waveform of the isolator. Even though the amplitude of the coil current waveform was increased by 100％, decreased by 90％, or delayed by 10％ of the period compared with the input current, similar transmitted output voltage waveform to the input current waveform was obtained due to hysteretic characteristics of the spin valves at the transmission speed of over 400 Mbit/s.