• 한국광학회지
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• 제8권2호
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• pp.107-110
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• 1997

NBUR(Negative Branch Unstable Ring) 공진기를 갖는 Nd:YAG 레이저의 원고리형 출력광속을 이용하여 무회절 광속을 발진시켰다. Scraper 출력경을 통하여 나오는 원고리형 광속은 평면화된 위상파면을 갖고 있을 뿐 아니라 균일한 공간적 세기 분포를 가지므로 무회절 광속을 발진시키는데 직접 사용할 수 있으며 높은 출력세기 밀도를 갖게 할 수 있다는 장점이 있다. 구성된 NBUR 레이저의 출력광속의 단면은 내경 2.5 mm 외경 5 mm인 크기를 가졌다. 5 m 초점거리를 갖는 Fourier 변환 렌즈를 레이저 출력경으로부터 초점거리만큼 떨어진 지점에 설치하여 원고리형 출력광속의 먼거리 형태를 관측하였으며, 렌즈를 통하여 13 m 이상의 위치에서도 광속의 퍼짐이 없음을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 E
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• pp.1800-1802
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• 1998

The Pohang Light Source (PLS) is a third generation 2 GeV synchrotron machine. An injection kicker modulator is positioned in the PLS storage ring tunnel. The kicker modulator is driving four kicker magnets simultaneously. The kicker magnets produce magnetic field to deflect the stored beam orbit in the storage ring closer to the injected beam from the PLS beam transfer line. The injected beam then falls into the storage ring beam dynamic aperture. The current kicker modulator was upgraded and installed on August 1995. Since then, the kicker modulator has shown very reliable and stable performance. The kicker modulator specifications are ${\sim}6.0{\mu}s$ full width, ${\sim}24$ kA peak current, and 10 Hz repetition rate. Output current waveform is a half sinusoid. Two thyratron switches(EEV CX-1536AX) are used in the kicker modulator. Total accumulated thyratron heater run hour is about 15,000 hours as of May 1998. Measurement result of spatial magnetic field distribution in the kicker magnet shows good uniformity.

• 한국자기학회지
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• 제2권2호
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• pp.163-168
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• 1992

포항 방사광 가속기 저장링용 시제품 2극전자석의 특성측정 및 보정결과에 대하여 기술 하였다. 전자석의 저장특성 측정을 위해 Hall probe mapping 기법과 rotating coil 기법과 rotating coil 기법을 동시에 사용하였다. 자장측정 결과로부터 2극전자석의 요구조건을 만족하도록 자극의 양 쪽 끝 부분을 수정하였다. 보정이 끝난 전자석은 2.0 GeV의 beam energy로 동작시킬 경우(1.058 Tesla) 약 99.7%의 효율을 얻었으며, 4극 이상의 다극 오차성분도 허용오차 범위 미만으로 포항 방사광 가속 기 저장링용 2극 전자석으로 적합함이 판명 되었다.

• 대한심미치과학회지
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• 제8권1호
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• pp.36-44
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• 1999

No one really doubts that the hottest area of dentistry in 21st century would most likely be 'implant'. With the support of a vast amount of research, implant has been successfully and rapidly absorbed into the field of general dentistry including private practitioners. For teeth with hopeless(or refractory) periodontitis or periapical pathosis, with no hesitation most dentists would think extraction as the sole treatment option followed by prosthodontic replacement possibly including implant. Not many dentists would take Trasplantation/Replantation as another treatment option for a particular condition. Dentistry is often more focused on 'Restoration' than 'Preservation' of natural dentition. 'Biologic Implant' is obviously much closer to the concept of 'Preservation'. Many different types of biologic implant system have been introduced to clinical dentistry so far. Many of those have failed to earn reasonable acknowledgement despite of the clinical success they brought. For some reason biologic implant has rather been alienated for long time. RPI(Ring Pin Implant) is designed to improve the prognosis and success rate of transplanted/replanted teeth. RPI is a Ti-based custom made implant system. It is fabricated either by electric casting or milling process. The major feature RPI gas is the 'ring & hole' structure. The hole should be no less than 1mm diameter to allow bone bridge formation thru it. The ring structure and bone bridge formation creates anti-torque activity, which largely increases the 'initial stability' of the transplanted/replanted teeth. It is also reported that RPI is beneficial in the aspect of resisting root resorption following replantation/transplantation procedure.

• 대한수학회보
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• 제22권2호
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• pp.117-119
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• 1985

Let R be a commutative noetherian ring with 1.neq.0, denoting by .nu.(I) the cardinality of a minimal basis of the ideal I. Let A be a polynomial ring in n>0 variables with coefficients in R, and let M be a maximal ideal of A. Generally it is shown that .nu.(M $A_{M}$).leq..nu.(M).leq..nu.(M $A_{M}$)+1. It is well known that the lower bound is not always satisfied, and the most classical examples occur in nonfactional Dedekind domains. But in many cases, (e.g., A is a polynomial ring whose coefficient ring is a field) the lower bound is attained. In [2] and [3], the conditions when the lower bound is satisfied is investigated. Especially in [3], it is shown that .nu.(M)=.nu.(M $A_{M}$) if M.cap.R=p is a maximal ideal or $A_{M}$ (equivalently $R_{p}$) is not regular or n>1. Hence the problem of determining whether .nu.(M)=.nu.(M $A_{M}$) can be studied when p is not maximal, $A_{M}$ is regular and n=1. The purpose of this note is to provide some conditions in which the lower bound is satisfied, when n=1 and R is a regular local ring (hence $A_{M}$ is regular)./ is regular).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 D
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• pp.2652-2654
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• 2005

A vacuum chamber temperature control system of Pohang Accelerator Laboratory (PAL) storage ring is a subsystem upgraded PAL control system, which is based upon Experimental Physics and Industrial Control System (EPICS) [1]. There are two control components, data acquisition system (SA120 data logger), development control system IOC (Input/Output Controller) at the storage ring of PAL. There are 240 vacuum chamber at the storage ring. It was a very important problem to solve how to monitor such a large number of vacuum chamber temperature distributed around the ring. The IOC connect MODBUS/JBUS field network to asynchronous serial ports for communication with serial device. It can simultaneously control up to 4 data acquisition systems. Upon receiving a command from a IOC running under Windows2k through the network, the IOC communicate through the slave serial interface ports to SA120. We added some software components on the top of EPICS toolkit. The design of the vacuum control system is discussed. This paper describes the development vacuum chamber temperature control system and how the design of this system.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.671-674
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• 2004

This paper presents design and analysis of multi-layered ring-dot type piezoelectric transformer. These transformers are useful for step up and step down. The transformers consist of disk type multi-layered piezoelectric ceramic plates. The finite element method(FEM) was used for analysis transformer. Vibration mode, electric field and equivalent elastic strain of piezoelectric transformer were simulated by changing frequency. As results, the strain was distributed in isolation part entirely. We can get the operated in step up transformer when the inner side electrode using by input parts. Also we can get the step down transformers using by input Part as outer side electrode. The step up ratio and step down ratio was increased by decreasing inner side electrode. The resonance frequency was increased by increasing inner side electrode when the transformer was operated in step down transformer. But the step up one was decreased. From these results, we can expect to multi-layered ring-dot type piezo transformers as step up and step down transformers.

• 한국광학회지
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• 제7권1호
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• pp.66-71
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• 1996

Floating guard ring(FGR) 구조를 갖는 avalanche photodiode(APD)는 제작이 매우 간단하고 제작된 소자의 신뢰성이 뛰어나기 때문에 고감도 특성의 고속동작 수광소자로 적합하다. 본 연구논문에서는 FGR APD의 구조설계, 제작공정 및 특성 측정 결과에 대해 논의하였다. FRG-APD는 이중확산 방법으로 제작하였으며 FGR이 가드링으로서 동작함을 2차원 이득특성 측정으로부터 확인할 수 있었다. 제작된 APD는 35GHz의 이득-대역폭 곱을 나타내었으며 2.5Gbps NRZ(Non-return-to-zero) 광신호에 대한 수신감도는 비트오율이 $10^{-9}$일 때 -31.9dBm이었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1779-1781
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• 1997

The 2.0 GeV Pohang Light Source (PLS) is consisted of a full energy Linac and a storage ring. Four kicker magnets are installed in the storage ring tunnel to move the stored beam orbit in the storage ring closer to the injected beam from the beam transfer line. The injected beam then falls into the storage ring beam dynamic aperture. A kicker magnet modulator drives all four kicker magnets to maintain field balance and also synchronized kick of the beam. The kicker modulator can handle 2 GeV full energy beam. The kicker magnet modulator is installed in the storage ring tunnel and under stable operation. Specification of the kicker magnet modulator is ${\sim}6.0{\mu}s$ pulse-width, 200 ns flat-top width with ${\pm}0.2%$ regulation, ${\sim}24\;kA$ peak current, and 10 Hz repetition rate. Two thyratron switches (EEV CX-1536AX) are used in the system. In this article, design, and experimental results of the kicker magnet modulator are discussed.

• Archives of Plastic Surgery
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• 제40권2호
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• pp.129-133
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• 2013

Background A pneumatic tourniquet is generally used to achieve a bloodless operation field in hand surgery. However, this has changed with tumescent solution-based wide-awake surgery. This study is a preliminary prospective case series study to elaborate the formula and indications of the tumescent technique in hand surgery without a tourniquet. Methods Seven patients (age range, 4 months to 37 years) underwent hand or upper extremity surgery for conditions such as nerve palsy, electric burn defect, fingertip injury, contracture, constriction ring syndrome, or acrosyndactyly. A "one-per-mil" tumescent solution (epinephrine 1:1,000,000+20 mg lidocaine/50 mL saline) was used to create a bloodless operating field without a tourniquet. Observation was performed to document the amount of solution injected, the operation field clarity, and the postoperative pain. Results The "one per mil" epinephrine solution showed an effective hemostatic effect. The tumescent technique resulted in an almost bloodless operation field in the tendon and in the constriction ring syndrome surgeries, minimal bleeding in the flap and contracture release surgeries, and acceptable bleeding in acrosyndactyly surgery. The amount of solution injected ranged from 5.3 to 60 mL. No patient expressed significant postoperative pain. Flap surgeries showed mixed results. One flap was lost, while the others survived. Conclusions Epinephrine 1:1,000,000 in saline solution is a potential replacement for a tourniquet in hand surgery. Further studies are needed to delineate its safety for flap survival.