• 공업화학
• /
• 제22권6호
• /
• pp.627-630
• /
• 2011

본 연구에서는 원료의 직접 주입법과 다양한 탄소수를 갖는 화합물을 이용하여 휘발유와 등유 등의 고급 유분을 생성할 수 있는 상업용 촉매 공정의 반응특성을 평가하고자 하였다. 이를 통하여 순간주입 반응기(spouted bed reactor) 상에서 상용촉매를 사용하여 반응 특성을 평가하였다. 또한 decane과 pentadecane을 이용하여 고정층 반응기와 순간주입 반응기의 특성을 비교하였다. 본 연구 결과, 반응온도 $550^{\circ}C$에서 가장 높은 휘발유 및 등유 수율을 기록하였다. 또한 순간 주입 반응기의 경우 주입량을 분할하여 주입하는 것보다 1회에 주입하는 것이 보다 효과적이었으며, 탄소수가 큰 물질을 사용할수록 반응활성이 증가하였다.

• Nuclear Engineering and Technology
• /
• 제56권4호
• /
• pp.1145-1152
• /
• 2024

To realize an initial objective of the negative ion-based neutral beam injection (N-NBI) at the Comprehensive Research Facility for Fusion Technology (CRAFT) test facility, which targets an H⁰ beam power of 2 MW at an energy of 200-400 keV and a pulse duration of 100 s, it is crucial to study the cesium dynamics of the negative ion source. Here a numerical simulation program CSFC3D is developed and applied to simulate the distribution and time dynamics of cesium during short pulses. The calculations show that most of the cesium on the plasma grid (PG) area originates from the release of cesium that is accumulated within the ion source in the plasma phase. Increasing the wall temperature reduces the loss of cesium on the wall of the ion source. Furthermore, the thickness of the cesium monolayer is directly influenced by the PG temperature. Both simulated and experimental results demonstrate that maintaining the PG temperature between 180 ℃ and 200 ℃ is essential for enhancing the performance of the ion source and optimizing the cesium behavior.

• Journal of international Conference on Electrical Machines and Systems
• /
• 제3권4호
• /
• pp.433-445
• /
• 2014

Single phase voltage source converter (VSC) is an important power electronic converter (PEC), including single-phase voltage source inverter (VSI), single-phase voltage source rectifier (VSR), single-phase active power filter (APF) and single-phase grid-connection inverter (GCI). As the fundamental part of large scale PECs, single-phase VSC has a wide range of applications. In the paper, as first, on the basis of the concept of the discontinuous pulse-width modulation (DPWM) for three-phase VSC, a new DPWM of single-phase VSR is presented by means of zero-sequence component injection. Then, the transformation from stationary frame (abc) to rotating frame (dq) is designed after reconstructing the other orthogonal current by means of one order all-pass filter. Finally, the presented DPWM based single-phase VSR is established analyzed and simulated by means of MATLAB/SIMULINK. In addition, the DPWMs presented by D. Grahame Holmes and Thomas Lipo are discussed and simulated in brief. Obviously, the presented DPWM can also be used for single-phase VSI, GCI and APF. The simulation results show the validation of the above modulation algorithm, and the DPWM based single-phase VSR has reduced power loss and increased efficiency.

• 대한소아치과학회지
• /
• 제33권4호
• /
• pp.710-716
• /
• 2006

소아치과에서 진정요법은 치과 환경에 대하여 공포를 가진 아동, 협조 전 단계의 아동, 장애를 가진 아동 그리고 구토반사 등을 보이는 환자에게 사용될 수 있다. 본 증례에서는 다발성 치아 우식증을 주소로 본원에 내원한 환아에서 1.0mg/kg 케타민과 $0.03{\sim}0.06mg/kg$ 미다졸람 그리고 아트로핀 정주 병용투여 하에 수복치료를 시행하였다. 치료시간의 연장과 적절한 진정 상태 유지를 위하여 케타민(0.33mg/kg)과 미다졸람 $1mg(0.03{\sim}0.05mg/kg)$을 혼합하거나 각각 추가 투여하였다. 지속적으로 환자의 활력징후를 관찰하면서 약물의 추가투여 용량을 결정하였다. 모니터링 장비로 맥박 산소 측정법(pulse oximetry), 전자심전도(electrocardiogram), 비혈관식혈압(NIBP : Noninvasive Blood Pressure)을 사용하여 맥박, 호흡수, 혈압, 산소 포화도 등을 측정하였다. 진료 과정동안 안전을 위해 미국 소아치과 학회(American Academy of Pediatric Dentistry ; AAPD)의 권고 사항을 준수하였다.

• Journal of Dental Anesthesia and Pain Medicine
• /
• 제20권6호
• /
• pp.397-402
• /
• 2020

Background: Inferior alveolar nerve block (IANB) is the most common, painful, and anxiety-provoking procedure involving needle insertion for anesthetic solution deposition. DentalVibeⓇ (DV) delivers vibration at a sustained frequency as a counter-stimulation to the site of injection, thereby alleviating pain. The aim of this study was to evaluate and compare the effectiveness of DV and lignocaine hydrochloride 2% gel (Lox 2% jelly) in pain reduction during IANB in children. Methods: A split-mouth randomized clinical trial was designed with a sample of 60 children (age, 6 to 12 years) requiring bilateral IANB for various dental procedures; DV was used while administering IANB and Lox 2% jelly was used as the topical anesthetic before administering IANB at subsequent appointments. During both appointments, pain perception was measured using the sound, eye, motor (SEM) scale and Wong-Baker faces pain rating scale (WBFPRS); oxygen saturation (SpO2) and pulse rate were measured using a pulse oximeter before, during, and after the IANB procedure. The obtained values were tabulated and subjected to statistical analysis. Wilcoxon test was used for intergroup comparison, and Friedman test, for intragroup comparison of measured variables at different treatment phases. Results: The medians and interquartile ranges of the WBFPRS scores recorded during the IANB procedure for DV and Lox 2% jelly were 2 (2-4) and 2 (0-2), respectively (P < 0.05). The SEM scale scores, mean SpO2, and pulse rate did not show any significant differences during the IANB procedure between both treatments. Conclusion: Both DV and Lox 2% jelly were found to be effective in pain reduction during IANB in children.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제40회 동계학술대회 초록집
• /
• pp.240-240
• /
• 2011

The first neutral beam injector (NBI-1) has been developed for the Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak. A first long pulse ion source (LPIS-1) has been installed on the NBI-1 for an auxiliary heating and current drive of KSTAR core plasmas. Performance of ion and neutral beam extractions in the LPIS-1 was investigated initially on the KSTAR NBI-1 system, prior to the neutral beam injection into the main plasmas. The ion source consists of a JAEA magnetic bucket plasma generator with multi-pole cusp fields and a set of KAERI prototype-III tetrode accelerators with circular apertures. The inner volume of plasma generator and accelerator column in the LPIS-1 is approximately 123 liters. Final design requirements for the ion source were a 120 kV/ 65 A deuterium beam and a 300 s pulse length. The extraction of ion beams was initiated by the formation of arc plasmas in the LPIS-1, called as an arc-beam extraction method. A stable ion beam extraction of LPIS-1 has been achieved up to an 100 kV/42 A for a 4 s pulse length and an 80 kV/25 A for a 14 s pulse length. Optimum beam perveance of 1.21 microperv has been found at an accelerating voltage of 80 kV. Neutralization efficiency has been measured by using a water flow calorimetry (WFC) method of calorimeter and an operation of bending magnet. The full-energy species of ion beams have been detected by using the diagnostic method of optical multichannel analyzer (OMA). An arc efficiency of the LPIS was 0.6~1.1 A/kW depending on the operating conditions of arc discharge.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.537-537
• /
• 2013

Cyclotron-accelerated ion beams are used for various researches, such as nuclear physics, nuclear chemistry, biotechnology, and material sciences including radio-isotope production. Recently considerable applications are asked to the cyclotron development undertaken to meet user requirements of various ions'energies, intensities, and their pulsed beams. For instance, a cocktail beam acceleration technique rapidly changing the ion species and energies was developed to irradiating integrated circuit chips. Also a chopping system in a cyclotron injection line is considered for producing a pulsed ion beam with a relatively long period compared with that generated by the resonance frequency. For the research in neutron time-of-flight measurement, a single-pulsed beam with a repetition interval of the order of mili-seconds or longer is necessary to have a good resolution and to remove background events. In this paper a feasibility of pulsed beam with an external ion source is simulated by adopting a combination system of a chopper accompanying with a bunching stage in the injection line and an additional chopper after the exit of the cyclotron in order to produce beam pulses with a range of $1{\mu}s{\sim}1ms$ periods from a resonance RF cycle. The pulseperiod will be adjusted by chopping the number of beam bunches from the injected pulses in the injection line. However, the longer pulses will have reduced number of beam pulses and sacrificed beam currents. Because the beam users need an intense single pulsed beam, a careful tuning of the acceleration phase and a high-intense external ion source are necessary to achieve an intense single-pulsed beam from the cyclotron. It is essential to strictly match the acceleration phase of injected beams in the central region of the cyclotron to improve its efficiency. An effect of space charge at each pulse from the ion source will be also considered.

• 한국광학회지
• /
• 제11권1호
• /
• pp.37-42
• /
• 2000

반도체 광 증폭기의 특성을 이해하기 위하여 비율 방정식을 수치 해석적으로 풀었다. 사용된 비율 방정식은 운반자 밀도와 자발 방출된 빛, 그리고 신호 빛을 위치와 시간의 함수로 기술할 수 있다. 사각 파형의 신호가 입사했을 경우에 대하여 위의 세가지 양을 구하여서 반도체 광증포기의 동적인 특성을 파악하였다. 파장 다중 광통신에서처럼 다중신호가 입사하는 경우의 비선형성을 분석하였다. 맥놀이에 의한 내부변조 변형을 계산하여 본 결과 파장 간격이 넓을수록 내부변조 변형은 줄어드는 결과를 정량적으로 얻었으며, 신호간의 채널 간섭은 신호의 세기가 감소하면 줄어드는 결과를 얻었다. 또한 신호로 사용되는 파장에서 충분히 멀리 떨어진 연속파동 레이저가 입사하는 경우에는 채널간의 신호간섭과 출력파형 변형이 감소하는 이득고정 효과가 나타남을 계산을 통하여 확인하였다.

• 전력전자학회논문지
• /
• 제7권2호
• /
• pp.149-157
• /
• 2002

본 논문에서는 공간벡터 PWM(SVPWM) 인버터에서 직류단 전압을 최대로 이용하기 위한 새로운 과변조 기법을 제안한다. 제안된 기법은 영-시퀀스 신호인 옵셋 전압 주입 원리에 근거한 SVPWM의 개념을 사용하였다. 제안된 과변조 기법에서는 폴전압을 간단히 수정함으로써 과변조 영역 전반에 걸터 인버터의 출력전압을 선형적으로 제어할 수 있게 하였다. 제안된 기법은 시뮬레이션과 실험을 통하여 그 타당성을 확인하였다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
• /
• pp.378-379
• /
• 2012

ITO 만큼 높은 전도성과 광학적 투과성을 갖는 Al-doped ZnO (AZO) 박막을 DC-Pulse magnetron sputtering을 이용하여 40 nm 두께로 증착 후 리소그라피 공정을 통해 $30{\mu}m$ 간격으로 패터닝 하였다. 간격 30 ${\mu}m$로 배열된 AZO를 촉매층으로 하는 수열합성법을 리사이클 공정을 반복하여 수행하여 ZnO 나노선을 성장시켰다. 이와 같이 AZO 전극 사이에 길이 $30{\mu}m$의 ZnO 나노선이 래터럴 구조로 연결된 소자의 $NH_3$ 가스감지 특성을 조사하였다. 합성된 나노선의 전기적, 광학적, 구조적인 특성을 분석하여 높은 가스 감지도를 예상할 수 있는 특성을 확인하였다. 제작된 가스센서를 진공 챔버에 설치 후 양 전극간에 동작전압(Operating voltage)을 1 V로 인가하여 고정한 후에 $NH_3$를 주입(Injection)과 퍼지(Purge)를 반복하며 그 주입량(10 ppm, 20 ppm, 40 ppm, 60 ppm)에 변화를 주었고, 그에 따른 전류변화를 관찰하여 $NH_3$ 가스감지특성을 평가하였다.