공진형 전력변환기를 위한 Phase-Locked Loop (PLL)의 특성 해석

안희욱,김학성,김상희 금오공과대학교 산업기술개발연구원 2000 産業技術開發硏究 Vol.16 No.-

For high efficiency and low noise operation of power converters, soft switching strategies are required. The resonant converters and/or inverters are suitable candidates for these purpose. Generally the PLL(Phase-Locked Loop) techniques are employed to make the switching frequency of resonant converters follow the resonant frequency which may vary due to the load variations. The conventional design guide of PLL is not suitable in these cases since the characteristics of converters or inverters are not considered. In this paper, the phase characteristics of a resonant inverter is analysed and added to the closed loop. And the design of PLL with digital phase detector is illustrated for the output frequency to track the resonant frequency of the inverter. The validity of the proposed scheme is verified by PSPICE simulation for the PLL system.

Dummy-Bar Head 鋼材의 材質向上

安秉旭,李相鎬,李柄榮,金志洙 한밭대학교 산업과학기술연구소 1994 논문집 Vol.2 No.-

Dummy-Bar Head is used for continuous casting equipment. It is heated up at high temperature and cooled down repeatedly in using. Then the thermal extension by thermal stress and high temperature oxidation occur to it. This easily results in heating damage because Head, contact with melting metal, appears in micro-crack and tension force. In other words, it is material that gives the greatest influence in endurance life. The method of study is to compare and evaluate present material and improved material by the new alloy design. In conclusion, the results are as follows : 1) I think that the following range is suitable to chemical component. ◁표 삽입▷(원문을 참조하세요) 2) Micro-crack occurs in repeated heating and cooling owing to decarburization and thermal extension. Adding carbide stability elements-Cr, Mn, and V-shows martensite and less micro-crack. 3) Dummy-Bar Head is a large cast steel, An effective heat treatment condition is to heat step by step and to cool by force at 880℃. After that, It is effective to cool at 600∼680℃. 4) Improved product maintains the even hardness value. And impact value is over three times higher than present product for repeated heating and cooling. 5) The transition range over the fracture toughness value has smaller in improved product than present product for repeated heating and cooling. Through the fracture toughness evaluation, the characteristics of change is evaluated in materials. And we can make the predictable criteria of life with Refrica method. According to the analysis and investigation of the real condition is use, the improved product is accomplished in optimal alloying design and product processing, and satifies the required condition. I think that it is widely used as proper materials to a higher temperature concerning the economy.

Barro-Fisher의 화폐중립성모형에 대한 Asako비판의 확대

안승욱 慶南大學校 産業經營硏究所 1993 産業經營 Vol.16 No.-

Single Nucleotide Primer Extension 기법을 이용한 SNP 연구

안영욱,예성수,박영홍 인제대학교 백병원 2002 仁濟醫學 Vol.23 No.5

Single nucleotide polymorphisms(SNPs) are the most frequent type of DNA sequence variation of individuals. They are defined by the presence of two alternative bases at a particular position in a DNA sequence and occur about one per 500-1000bp in the human genome. The recent completion of the first reference sequence of the human genome has provided a basis for comprehensive analysis of sequence variation in man. The identification and dense mapping of SNPs is of considerable significance for association studies of complex diseases, pharmacogenetics, population genetics and physical mapping. Their use as genetic markers is favored by their high abundance, low mutation rate and the easy automation of typing. With the development of ABI Prism 3100 or 3700 system, single nucleotide primer extension, we car get a straightforward and large-scale method for validation of or comparative genotyping of known SNPs and point mutations. In the mini sequencing primer extension reaction, a DNA polymerase is used specifically to extend a primer that anneals immediately adjacent to the nucleotide position to be analyzed with a single labeled nucleoside triphosphate complementary to the nucleotide at the variant site. The reactor allows highly specific detection of point mutations and single nucleotide polymorphisms(SNPs) without direct sequencing. Because all SNPs can be analyzed with high specificity at the same reaction conditions, mini sequencing is a promising reaction principle for multiplex high-throughput genotyping assays. It is also a useful tool for accurate quantitative PCR-based analysis. This review discusses the advanced biotechnique.

사회주의 계획경제체제의 화폐ㆍ금융과 화폐수량설

안승욱 慶南大學校 産業經營硏究所 2001 産業經營 Vol.28 No.-

구사회주의 경제개혁에 있어서 사유화의 한 관점: 제도와 조직측면

안승욱 慶南大學校 産業經營硏究所 1994 産業經營 Vol.17 No.-

호흡곤란과 주시 유발 눈떨림을 동반한 비전형적 밀러-피셔 증후군 1례

안성민,김호창,정보영,서억수,정병욱 동국대학교 의학연구소 2009 東國醫學 Vol.15 No.2

We report a case of atypical Miller-Fisher syndrome with respiratory distress and gaze evoked nystagmus. A 70 year-old man who has a hepatocellular carcinoma with metastasis to the lung was referred complaining of acute onset diplopia. He showed a 15 prism diopter esotropia, gaze evoked nystagmus at lateral gaze, and limitation of the extraocular movement at any directional gaze. And deep tendon reflexes were absent. The results of brain MRI and cerebrospinal fluid analysis were normal, so we can differentiate an atypical Miller-Fisher syndrome with the Guillain-Barre syndrome and other CNS problems. After 2 weeks, diplopia, nystagmus, and extraocular movement were improved spontaneously, but deep tendon reflexes were still absent. The differential diagnosis of the Miller-Fisher syndrome is important because it can be recovered spontaneously. We can diagnose a case of atypical Miller-Fisher syndrome which represented normal findings of brain MRI, CSF analysis. 호흡곤란과 주시유발 눈떨림을 동반한 비전형적인 밀러-피셔 증후군 (atypical Miller-Fisher syndrome) 1례를 보고한다. 70세 남자환자가 간세포암과 폐전이로 내과 입원중에 갑자기 생긴 복시를 주소로 의뢰되었다. 제 1안위에서 15 PD의 내사시가 있었고, 측면주시시 주시 유발 눈떨림이 있었다. 모든 주시방향에서 눈운동 장애가 있었으며 사지의 심부건반사가 없었다. 두부 MRI및 뇌척수액검사에서 이상이 확인되지 않아, 중추신경계의 이상 및 길랑-바레 증후군(Guillain-Barre syndrome)과 감별하여 비전형적 밀러-피셔 증후군으로 진단하였다. 2주 후 경과관찰에서 복시와 주시유발 눈떨림, 안구운동제한에 호전이 있었으며 , 심부건반사의 소실은 회복되지 않았다. 밀러-피셔 증후군은 대개가 치료없이 회복되어서 다른 질환과의 감별이 중요하다. 저자들은 두부 MRI및 뇌척수액검사에서 정상 소견을 확인하고 비전형적 밀러-피셔 증후군을 감별 진단할 수 있었기에 이를 보고한다.

부분 치수절단술을 이용한 복잡 치관파절의 치료 : 증례보고

안병덕,김영재,장기택,이상훈,김종철,한세현,김정욱 大韓小兒齒科學會 2008 大韓小兒齒科學會誌 Vol.35 No.2

혼합 치열기 및 초기 영구치열기의 소아,청소년에서 외상에 의한 치관 파절은 빈번하게 발생한다. 치관파절은 치수의 노출 유무에 따라 단순 치관파절,복잡 치관파절로 분류된다. 치수가 노출된 복잡 치관파절의 경우 치수에 대한 고려 및 처치가 필수적인데,초기 영구치열기에는 전치부 치근의 발육이 완전히 이루어지지 않았기 때문에 완성된 치근을 가지는 치아보다 치료가 복잡하다. 치료의 목적은 적절한 치수 치료를 통해 치근의 완성을 도모하는 것으로 이를 위해 직접 치수복조술,부분 치수절단술,치경부 치수절단술의 방법을 이용한다. 이 중 부분 치수절단술은 성공률도 높으며 치경부 치수를 보존하기 때문에 여러 장점을 지니는 치료방법이다. 복잡 치관파절을 주소로 내원한 환자에서 부분 치수절단술을 시행하여 양호한 결과를 나타내어 이를 보고하는 바이다. Traumatic crown fracture in mixed dentition or early permanent dentition is relatively common. Crown fracture is classified into simple or complicated crown fracture by the presence of pulp exposure. The condition of pulp must be considered in treatment of crown fractures with pulp exposure. Treatment of immature crown-fractured incisor with pulp exposure is more complex because of its incomplete root formation. Pulp capping, partial pulpotomy, cervical pulpotomy can be used for continuous root development in immature crown-fractured incisor with pulp exposure. The success rate of partial pulpotomy is very high and there are several advantages of partial pulpotomy because the cell-rich coronal pulp tissue is preserved. This paper reports 2 cases of crown-fractured permanent incisors with pulp exposure that had been treated by partial pulpotomy successfully.

공동주택에 적용되는 공기식 열교환기의 성능평가에 관한 연구

김상민,안병욱,손장열 대한건축학회 2005 대한건축학회논문집 Vol.21 No.3

Indoor Air Quality has been significantly degraded due to the improvement of the airtightness of residential and commercial combined high-rise apartment buildings. In order to handle the problems related to insufficient ventilation, the application of mechanical ventilation system is required in detached residences or apartments in the country. As an alternative, air-to-air heat recovery ventilators are used at initial stage for energy conservation using waste heat recovery and the improvement of IAQ in high-rise apartments, currently being more widely used even in apartments and detached residences. Due to this trend, relevant institutes and organizations are making standards for the evaluation of HRV(Heat Recovery Ventilator) performance, but research related to the evaluation of HRV performance are not sufficiently done in this circumstance before applying in real buildings. Therefore, the purpose of this study is to compare and evaluate international and domestic standards for the evaluation of HRV performance, and to provide guideline for the adequate selection of effective HRV by evaluating the performance synthetically in terms of major items.

초공간을 고려한 AISI 304강 열화신호의 카오스성 평가

오상균,안병욱 한밭대학교 생산기반기술연구소 2002 생산기반기술연구소 논문집 Vol.2 No.1

This study proposed the analysis and evaluation method of time series ultrasonic signal using the chaotic feature extraction for degradation extent. Features extracted from time series data using the chaotic time series signal analyze quantitatively material degradation extent. In this study, constructed strange attractor on hyperspace and got value using fractal dimension, Lyapunov exponent. The Lyapunov exponent is a measure of the rate at which nearby trajectories in phase space diverge. Chaotic trajectories have at least one positive Lyapunov exponent. The fractal dimension appears as a metric space such as the phase space trajectory of a dynamical system. In experiment, fractal(correlation) dimensions and Lyapunov exponents showed values of mean 3.837∼4.211 and 0.054∼0.078 in case of degradation material. The proposed chaotic feature extraction in this study can enhances ultrasonic pattern recognition results from degradation signals.