• 제목/요약/키워드: Regular variation

검색결과 218건 처리시간 0.026초

과전류 및 단락사고 방지용 전기안전 제어장치에 관한 연구 (A Study on Electric Safety Control Device for Prevention of Over Current and Short Circuit Faults)

  • 조시환;곽동걸;정도영;심재선;김정숙
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2008년도 제39회 하계학술대회
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    • pp.2100-2101
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    • 2008
  • This paper is studied on a protective control system for electrical fire and electrical faults due to over current or electric short circuit faults by using electrical thermal characteristics of PTC (Positive Temperature Coefficient) thermistor and current response characteristics of high sensitive reed switch. The PTC thermistor has characteristic of positive resistivity temperature coefficient according to the temperature variation, which is construction of a regular square and cube demarcation with BaTiO3_Ceramics of positive temperature coefficient. Also PTC thermistor shows the phenomenon which is rapidly increased in the resistivity if the temperature is increased over Curie temperature point, and reed switch, which is used for electrical fault current sensing devices, have a excellent characteristic of response velocity in degree of ${\mu}s{\sim}ms$ that sensing magnetic flux in proportion to dimension of line current. This paper is proposed on a protective control system use PTC thermistor and reed switch for sensor which is protected from electrical fire due to overload faults or electric short circuit faults. Some experimental results of the proposed electric safety control device are confirmed to the validity of the analytical results.

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Cervical Cytological Screening Results of 8,495 Cases in Turkey - Common Inflammation but Infrequent Epithelial Cell Abnormalities?

  • Daloglu, Ferah Tuncel;Karakaya, Yeliz Arman;Balta, Hilal;Altun, Eren;Duman, Aslihan
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권13호
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    • pp.5127-5131
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    • 2014
  • Background: Cervical cancer is the ninth most common cancer among females in Turkey. Cervical smear is a routine screening test used for the detection of cervical abnormalities and also it detects certain infections of the cervix. Objective: To analyze cervical smear results of our clinic in order to determine most frequent pathology of the women in North Eastern Anatolia Region of Turkey. Materials and Methods: In a retrospective study design, 8,495 cervical cytology cases diagnosed at the Pathology Department of the Regional Education and Research Hospital in Erzurum over the last one and half years extending from August 2012 to December 2013 were investigated. Results: The most common diagnosis was found to be inflammation, 65.5 % (5,566 out of 8,495), and the least was squamous epithelial abnormalities 0.2% (13 out of 8,495). There was some variation among the three pathologists regarding diagnosis but findings for the latter. Conclusions: Regular cervical smear tests are one of the most important strategies in early diagnosis of cervical cancer but there are conflicting data regarding the prevalence of epithelial cell abnormalities in Turkey, and the reasons o f this should be investigated.

부분반사 전면 및 완전반사 후면을 갖는 반무한 방파제 또는 방파제 개구부에 의한 파의 산란 (Wave Scattering by a Semi-infinite Breakwater or a Breakwater Gap with Partially Reflective Front and Fully Reflective Back)

  • 서경덕;김한나
    • 한국해안해양공학회지
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    • 제19권3호
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    • pp.183-193
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    • 2007
  • 부분반사 전면 및 완전반사 후면을 갖는 반무한 방파제 및 방파제 개구부에 의한 파의 산란 현상에 대한 해석 해를 유도하였다. 이는 수심이 일정하고 파가 방파제에 직각으로 입사하는 경우에 적용 가능하며, 선형파 이론에 근거하여 변수 변환 및 좌표 변환을 통해 지배 방정식을 상미분 방정식으로 전환하여 구하였다. 본 연구에서 유도된 해석 해는 유한 요소 수치 모델의 결과와 비교하여 그 정확도를 비교하였는데, 꽤 정확한 결과를 보인다는 것을 알 수 있었다. 유도된 해석 해를 이용하여 방파제에서의 반사율에 따른 항 입구에서의 정온도에 미치는 효과를 조사하였다.

EVOLUTION OF INTERNAL WAVES NEAR A TURNING POINT IN THE SOUTH CHINA SEA USING SAR IMAGERY AND NUMERICAL MODELS

  • Kim, Duk-Jin;Lyzenga, David R.;Choi, Woo-Young;Kim, Youn-Soo
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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    • pp.61-64
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    • 2007
  • Subsurface Internal Waves (IWs) can be detected in satellite images as periodic alternating brighter/darker stripes. It is known that there are two types of IWs - depression type and elevation type - depending on the water depth in stratified oceans. In this study, we have quantitatively verified the process of converting polarity from depression waves to elevation waves using ERS-2 SAR images acquired over the northern South China Sea. We simulated the evolution of IWs near a turning point with a numerical model for internal wave propagation. The simulation results near the turning point clearly showed us not only a conversion process of IWs from depression to elevation waves, but also a similar wave pattern with the observed SAR image. We also simulated SAR intensity variation near the turning point. The upper layer currents were computed at regular intervals using the numerical model, as the IWs were passing through the turning point. Then, an integrated hydrodynamic-electromagnetic model was used for simulating SAR intensity profiles from the upper layer currents at each position. The simulated SAR intensity profiles at each position were compared with the observed SAR intensities.

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Identification of QTL for Early Heading Date of H143 in Rice

  • Yoo, Jeong-Hoon;Yoo, Soo-Cheul;Zhang, Haitao;Cho, Sung-Hwan;Paek, Nam-Chon
    • Journal of Crop Science and Biotechnology
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    • 제10권4호
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    • pp.243-248
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    • 2007
  • Rice is a facultative short-day plant that flowers in response to reduced day lengths. This study was conducted to identify quantitative trait loci(QTL) for the early heading date(EHD) using H143 line showing extreme EHD compared to other regular cultivars in rice. The japonica H143 was crossed with a japonica cultivar 'Dongjinbyeo' as well as a tongil cultivar 'Milyang23' to measure the inheritance mode of EHD and identify major QTL conferring EHD, respectively. Pooling test revealed that segregation distortion occurred on chromosome 7 and subsequent linkage map was constructed using 10 SSR markers. QTL analysis using Q-gene 3.06 revealed that the EHD trait in H143 was largely controlled by two major QTL, EH7-1 and EH7-2, accounting for more than 40% of genetic variation that were closely related to the previously reported QTL, Hd4 and Hd2, respectively. This result suggests that these two QTL markers may be a useful source for the control of heading date in rice breeding programs.

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질석화가 진행된 풍화단면에서의 광물조성과 주원소의 변화 (Mineralogical and Chemical Variation in Weathering Profile on Ultramafic Rocks During Vermiculitization)

  • 문희수;송윤구;신상은
    • 자원환경지질
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    • 제26권1호
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    • pp.29-40
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    • 1993
  • Several vermiculite deposits occur as the alteration product from phlogopite in ultramafic rock, in the Hongseong and Cheongyang area, South Korea. Some quarries show well-defined weathering profile. Samples collected from those quarries were examined by XRD and chemistry to define a vertical variations in mineralogy and chemistry of the weathering profile developed on ultramafic rocks. The analysis by X-ray diffractometry showed that mineral compositions changed continuously as depth of profile increasing, the vermiculite-the phlogopite/vermiculite interstratified-the phlogopite. Chemical analysis of bulk samples in altered zone revealed that regardless of composition and kinds of mineral in the rock, there are significant increase of MgO, CaO and $H_2O$, and decrease of K as depth of profile decrease reflecting the characteristics in vermiculitization. Also, there was a tendency that weathering indicies of each sample horizon change gradually with increasing depth. This tendency can be explained as variations of degree of vermiculitization. The regular changes of mineralogical and chemical composition in vertical profile suggest that weathering is the most important process in vermiculitization in this area.

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중금속 오염 농경지 토양의 안정화 처리공법 효과 비교 (A Comparison on the Effect of Stabilization Methods for Rice Paddies contaminated by Heavy Metal)

  • 유찬;윤성욱;박진철;이정훈;최승진;최덕용;이지민
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2009년도 춘계 학술발표회
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    • pp.819-835
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    • 2009
  • In order to investigate the field application of selected stabilization methods(cover soil method, surface and total interval treatment of embankment method) on rice paddies contaminated by heavy metals, column test was carried out with heavy metal-contaminated soils collected from rice paddies around abandoned mine site. Columns were made by acrylic and filled with untreated soil, treated soil mixed with amendments(lime stone and steel refining slag) and uncontaminated cover soil according to the design report. Distilled water was discharged into the columns with the velocity of 1 pore volume/day. During test, pH, EC, and heavy metal concentration were measured in the regular term. The column test result showed that the selected stabilization methods were effective remediation method to stabilize heavy metals in paddy soils, but it was also expected that application of surface treatment methods was required the careful observation on pH variation due to the lowest increment.

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Proximate Composition, Amino Acid, Mineral, and Heavy Metal Content of Dried Laver

  • Hwang, Eun-Sun;Ki, Kyung-Nam;Chung, Ha-Yull
    • Preventive Nutrition and Food Science
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    • 제18권2호
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    • pp.139-144
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    • 2013
  • Laver, a red algae belonging to the genus Porphyra, is one of the most widely consumed edible seaweeds. The most popular commercial dried laver species, P. tenera and P. haitanensis, were collected from Korea and China, respectively, and evaluated for proximate composition, amino acids, minerals, trace heavy metals, and color. The moisture and ash contents of P. tenera and P. haitanensis ranged from 3.66~6.74% and 8.78~9.07%, respectively; crude lipid and protein contents were 1.96~2.25% and 32.16~36.88%, respectively. Dried lavers were found to be a good source of amino acids, such as asparagine, isoleucine, leucine, and taurine, and ${\gamma}$-aminobutyric acid. K, Ca, Mg, Na, P, I, Fe, and Se minerals were selected for analysis. A clear regional variation existed in the amino acid, mineral, and trace metal contents of lavers. Regular consumption of lavers may have heath benefits because they are relatively low in fat and high in protein, and contain functional amino acids and minerals.

진동 마이크로 밀링을 이용한 미세 반복 패턴 가공 기술 연구 (Machining of Repetitive Micro Patterns using Oscillation Micro Milling)

  • 노승국;김경호;박종권
    • 한국정밀공학회지
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    • 제31권5호
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    • pp.381-387
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    • 2014
  • This paper introduces a system to machine micro-sized patterns effectively on surface based on micro-milling process using tools with simultaneous rotation and oscillation, oscillation micro milling. To review the effectiveness of proposed concept, we integrated a micro-spindle supported by active magnetic bearings with a precision 3-axis air bearing stage using double-wedge mechanism, and tested this oscillation milling. Two types of oscillation milling were tested, which are linear oscillation milling with a flat end mill and elliptical oscillation milling with a ball end mill with 0.3 mm of diameter. The spindle was rotating 110 krpm and workpiece was moving constant speed of 2~8 mm/sec during the oscillation milling. As the results, multiple oval shape dimples were generated in regular spacing, and the variation of elliptical motion made different shapes of patterns. The results showed that proposed oscillation milling can be successfully used for machining repeated micro-patterns.

SM490A와 SS400 대기부식 시편의 피로 특성 평가 (Fatigue of SS490A and SS400 Corroded Specimens)

  • 구병춘
    • 한국철도학회논문집
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    • 제12권5호
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    • pp.725-731
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    • 2009
  • 강 교량, 선로 구조물, 차량 구조물 등 철도분야에서 강 재료가 많이 사용되고 있다. 설계, 강도평가, 잔존수명 평가 등을 위하여 부식된 강 재료에 대한 인장강도, 피로강도 등이 필요하지만 우리나라의 경우 이 분야의 연구가 미진하여 축적된 데이터가 많지 않다. 본 연구에서는 철도 분야에서 많이 사용되는 대표적인 강 재료에 속하는 SM490A와 SS400에 대해 대기부식 시험절차를 확립하고 많은 시편을 대기부식에 노출시켜 일정한 시간 간격으로 수거하여 인장 및 피로시험을 수행하여 부식시간의 경과에 따른 인장 및 피로강도의 변화를 측정하였다. 처음 3-4개월 기간에 피로강도가 많이 저하하였고 그 이후에는 완만히 변화하였다. 그리고 후열처리 한 시편이 부식에 대한 저항이 더 크다는 것도 알 수 있었다.