• 한국전기전자재료학회논문지
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• 제27권2호
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• pp.76-80
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• 2014

Dual-gate PCRAM which unify capacitor-less DRAM and NVM using a PCM instead of a typical SONOS flash memory is proposed as 1 transistor. $VO_2$ changes its phase between insulator and metal states by temperature and field. The front-gate and back-gate control NVM and DRAM, respectively. The feasibility of URAM is investigated through simulation using c-interpreter and finite element analysis. Threshold voltage of NVM is 0.5 V that is based on measured results from previous fabricated 1TPCM with $VO_2$. Current sensing margin of DRAM is 3 ${\mu}A$. PCM does not interfere with DRAM in the memory characteristics unlike SONOS NVM. This novel unified dual-gate PCRAM reported in this work has 1 transistor, a low RESET/SET voltage, a fast write/erase time and a small cell so that it could be suitable for future production of URAM.

• 한국조명전기설비학회지:조명전기설비
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• 제8권3호
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• pp.54-63
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• 1994

본 연구에서는 판상스페이서 위에 침전극을 고정하고 gap간격 40[mm]에 평판전극을 설치한 gap 간에 10[mm]간격으로 나누어 각 구간내에 스페이서와 같은 재질의 Barrier를 설치하고 파티클을 두었을 때 AC 및 정극성 DC 전압에서의 방전로와 FOV에 대해 연구한 결과 다음과 같은 결론을 얻엇다. 1) Barrier가 고전위측에 위치한 경우와 파티클이 Barrier뒤에 은폐된 경우가 FOV가 높다. 2) 침전극 선단에 파티클 위치할 때 심한 FOV의 감소가 있다. 3) 파티클이 전극간에 게재되면 방전로는 파티클을 경유하므로 FOV는 감소한다.

• 한국자동차공학회논문집
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• 제1권2호
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• pp.27-33
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• 1993

Using the solenoid driven gas injection valve, Hydrogen fuel supply system was made. It was attached to a single cylinder research engine and intake port injection type hydrogen fueled S.I. engine was constructed. Engine performance, emission characteristics, and abnormal combustion were studied through the engine test performed with the variations of fuel-air equivalence ratio and spark timing. Compared with gasoline, hydrogen burns so fast that cylinder peak pressure and temperature are higher and NO is emitted more at full load condition. IN the case of intake port injection type engine, COVimep becomes lower due to the well-mixing of air and fuel, and engine output is lower owing to the low volumetric efficiency. As fuel-air equivalence ratio goes up, the combustion speed increases, and COVimep decreases. NO emission peaks slightly lean of stoichiometric. As spark timing advances and fuel-air equivalence ratio goes up, the cylinder peak pressure and temperature become higher, so abnormal combustions take place easily.

• 한국분무공학회지
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• 제28권1호
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• pp.32-42
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• 2023

In this study, spray characteristics of n-heptane and propane were investigated under different injection pressure using various imaging techniques such as Mie-scattering, DBI (diffuse back-illumination), and Schlieren imaging techniques. NI compact RIO system was used to control a test injector. Spray penetration length, length-to-width ratio and number of black pixels were calculated by using MATLAB software to compare spray characteristics of each fuel. Longer spray penetration length and higher length-to-width ratio were observed in propane spray because of flash boiling caused by high saturated vapor pressure. Spray collapse occurred in propane spray due to the high plume-to-plume interaction. Moreover, rapid evaporation occurred in propane spray, so that nozzle tip wetting could not be observed. Rapid evaporation of propane also caused fewer residual droplets compared to n-heptane spray. Therefore, propane is advantageous in reducing the generation of soot emission from large droplets that are not atomized. However, additional evaluation should be conducted considering combustion efficiency and the possibility of deposits by nozzle tip icing during fuel injection.

• 대한전자공학회논문지SD
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• 제43권12호
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• pp.55-64
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• 2006

본 설계에서는 무선 랜 등 최첨단 무선 통신 및 고급영상 처리 시스템과 같이 고해상도와 높은 신호처리속도, 저전력 및 소면적을 동시에 요구하는 고성능 집적시스템 응용을 위해 기존의 보정기법을 사용하지 않는 14b 70MS/s 0.13um CMOS A/D 변환기(Analog-to-Digital Converts- ADC)를 제안한다. 제안하는 がU는 중요한 커패시터 열에 인접신호에 덜 민감한 3차원 완전 대칭 구조의 레이아웃 기법으로 소자 부정합에 의한 영향을 최소화하였고, 3단 파이프라인 구조로 고해상도와 높은 신호처리속도와 함께 전력 소모 및 면적을 최적화하였다. 입력 단 SHA 회로에는 Nyquist 입력에서도 14비트 이상의 정확도로 신호를 샘플링하기 위해 게이트-부트스트래핑 (gate-bootstrapping) 회로를 적용함과 동시에 트랜스컨덕턴스 비율을 적절히 조정한 2단 증폭기를 사용하여 14비트에 필요한 높은 DC전압 이득을 얻음과 동시에 충분한 위상 여유를 갖도록 하였으며, 최종 단 6b flash ADC에는 6비트 정확도 구현을 위해 2단 오픈-루프 오프셋 샘플링 기법을 적용하였으며, 기준 전류 및 전압 발생기는 온-칩으로 집적하여 잡음을 최소화하면서 필요시 선택적으로 다른 크기의 기준 전압 값을 외부에서 인가할 수 있도록 하였다. 제안하는 시제품 ADC는 0.13um CMOS 공정으로 요구되는 2.5V 전원 전압 인가를 위해 최소 채널길이는 0.35um를 사용하여 제작되었으며, 측정된 DNL 및 INL은 14비트 해상도에서 각각 0.65LSB, 1.80LSB의 수준을 보이며, 70MS/s의 샘플링 속도에서 최대 SNDR 및 SFDR은 각각 66dB, 81dB를 보여준다. 시제품 ADC의 칩 면적은 $3.3mm^2$이며 전력 소모는 2.5V 전원 전압에서 235mW이다.

• 대한전자공학회논문지SD
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• 제43권5호
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• pp.54-63
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• 2006

본 논문에서는 4세대 이동 통신 시스템에서 요구되는 사양을 위해, 해상도, 동작속도, 칩 면적 및 소모 전력을 최적화한 14b 100MS/s 0.18um CMOS ADC를 제안한다. 제안하는 ADC는 동작 모델 시뮬레이션을 통해 최적화된 구조를 분석 및 검증하여 3단 파이프라인 구조로 설계하였으며, Nyquist 입력에서도 14 비트 수준의 유효비트 수를 가지는 광대역 저잡음 SHA 회로를 기반으로 하고, MDAC에 사용되는 커패시터의 소자 부정합에 의한 영향을 최소화하기 위하여 3차원 완전 대칭 구조를 갖는 레이아웃 기법을 적용하였다. 또한, 100MS/s의 동작 속도에서 6 비트의 해상도와 소면적을 필요로 하는 최종단의 flash ADC는 오픈 루프 오프셋 샘플링 및 인터폴레이션 기법을 사용하였다. 제안하는 시제품 ADC는 SMIC 0.18um CMOS 공정으로 제작되었으며, 측정된 DNL과 INL은 14비트 해상도에서 각각 1.03LSB, 5.47LSB 수준을 보이며, 100MS/s의 샘플링 속도에서 SNDR 및 SFDR이 각각 59dB, 72dB의 동적 성능을 보여준다. 시제품 ADC의 칩 면적은 $3.4mm^2$이며 소모 전력은 1.8V 전원전압에서 145mW이다.

• 대한한의학원전학회지
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• 제31권1호
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• pp.57-78
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• 2018

Objectives : The paper uses recitation test, one of the study and evaluation methods in the Korean Medical Classics, to provide a basis upon which thoughts can be given to the education of Korean Medicine, and furthermore the essence of education itself. Methods : 1. The paper reviewed how recitation tests were performed in Goryeo and Joseon. 2. The paper introduces the methods of applying recitation test to the education of the Korean Medical Classics and their results. The paper furthermore discussed possible improvements. 3. The paper pondered on the traditional aspects of the significances (principles) of recitation tests and their cognitive neuroscience aspects. Results : 1. The imperial examinations for medical officers during Goryeo and Joseon both performed recitation tests, and the subject of these tests were given more weight than other subjects. 2. Recitation test is a form of education that revolves around the learners. It requires a detailed plan of execution for it to be effective. 3. The significances (principles) of recitation test are reviewed from the aspect of cognitive neuroscience, and the deductions from the traditional aspects are made into "conceptual abstract, come to things & run out knowledge, and flash back." Conclusions : Recitation test was the humanity's way of conserving and conveying knowledge & wisdom from the times before the invention of letters. This method is the oldest education method of acquiring concepts that are generalized and made abstract through indirect experiences. This method is still effective today. In the education of the Korean Medical Classics, this method was used to supplement the public education method and create an education method that revolves around individual learner in a way that utilizes the strengths of education in apprenticeship.

• 대한기계학회논문집B
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• 제35권4호
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• pp.439-444
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• 2011

새 가스그룹의 가스기기 호환성 시험가스 결정을 위해 현 13A 가스그룹의 시험가스와 13A 가스기기의 가스호환성(효율 포함) 관계를 실험적으로 규명하였다. 이 시험결과로부터 새 가스그룹의 불완전 연소 및 화염 부상 한계 가스는 각각 새 가스그룹의 웨버지수 상한보다 2 % 크고, 하한 보다는 1 % 작은 값이 적정함을 알 수 있었다. 또한 효율 시험용 R 가스의 조성은 메탄 96 mol %와 프로판 4 mol %가 가장 적정하며, 일반 효율 시험시에는 공급 천연가스도 R가스로 사용될 수 있음을 확인하였다. 그리고 역화 한계 가스 내 수소 농도는 기존 30 vol %에서 EN437과 같이 23 vol %로 낮출 수 있는 것으로 분석되었다.

• Archives of Plastic Surgery
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• 제33권4호
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• pp.521-524
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• 2006

Purpose: The history of biometry dates back to ancient Greek. The ideal body ratio from biometry is used as a guideline in many works of art. Biometry is also used as a medical standard to determine normal or abnormal. Since the biometry of face is so complicated, many surgeons tend to regard preoperative evaluation as a bother and substitute medical records with some photographs. We introduce a new method to measure $MRD_1$ and levator function using digital photographs, which becomes widely used lately. Methods: $MRD_1$ can be measured with the primary-gaze-view photo which is magnified by PhotoshopR 7.0.1. The distance from coneal reflex of ring flash to upper eyelid margin is converted to mm-unit using the piece of ruler attached on the patient's face. Levator function can be measured with up-gaze-view photo and down-gaze-view photo which are superimposed on another. The excursion distance of upper eyelid margin (a) and the excursion distance of eyebrow (b) are measured respectively. The levator function can be assessed through subtraction of two values (a-b). This method is simple and precise and can be applied directly to patient without photos. Results: Using magnified digital photos and computer, this method can reduce personal error and instrumental error. Taking some digital photos doesn't take long time, so it can reduce the effort of preoperative evaluation and discomfort of patients. Conclusion: Digital photo-biometry is useful for retrospective study. Especially reducing personal error, it is useful when the number of specimens is huge. New levator function test is much more useful for Asian-specific eyes than Berke's method allowing frontalis muscle compensation.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.453-459
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• 2004

An axially staged combustor equipped with an LPP combustion system and CMC liner walls has been investigated for stable combustion and low NOx emissions for the ESPR project. Several fuel injectors were designed and manufactured for the LPP burner, and single sector combustor tests were conducted to evaluate fundamental combustion characteristics such as emissions, instabilities, auto-ignition, and flash back at typical operating conditions from idle to Mn 2.2 cruise. The latest test results showed that the LPP burner had a good potential for the low NOx target. It was also found that the NOx emission level was greatly affected by a distortion in the air flow velocity field upstream of the LPP burner due to the diffuser and fuel feed arm. The CMC material was investigated to apply for the high temperature and low NOx combustor. Annular combustor liner walls were manufactured with the CMC material, and they have been tested at low pressure conditions to evaluate the soundness of the material and the mounting and seal system. This paper reports the latest research activities on the LPP combustion system and CMC liner walls for the ESPR project.