• Advances in nano research
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• 제8권2호
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• pp.157-167
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• 2020

This paper studies forced vibrational behavior of porous nanocrystalline silicon nanoshells under radial dynamic loads using strain gradient theory (SGT). This type of material contains many pores inside it and also there are nano-size grains which define the material character. The formulation for nanocrystalline nanoshell is provided by first order shell theory and a numerical approach is used in order to solve nanoshell equations. SGT gives a scale factor related to stiffness hardening provided by nano-grains. For more accurate description of size effects due to nano-grains or nano-pore, their surface energy influences have been introduced. Surface energy of inclusion exhibit extraordinary influence on dynamic response of the nanoshell. Also, dynamic response of the nanoshell is affected by the scale of nano-grain and nano-pore.

• 한국철도학회논문집
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• 제7권4호
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• pp.406-411
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• 2004

BOM(Bill of Materials) is a listing or description of raw materials, parts, and assemblies that define a product. In order to evaluate the performance of proposed BOM management system, which is very important to maintenance information system of urban transit. We develop component based BOM data and rule-set to design data structure that is mutually independent and integrated efficiently. It divides data whit management interface using component technology. The component based master BOM have advantage in database size and flexibility. Flexibility is measured as the number of updating records in accordance with added new product or engineering change. In database size, component based BOM is the best. we develop master BOM management system in web environment.

• 한국전기전자재료학회논문지
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• 제32권5호
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• pp.361-365
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• 2019

Although there is no strict definition of a power semiconductor device, a general description is a semiconductor that has capability to control more than 1 W of electricity. Integrated gate bipolar transistors (IGBTs), which are power semiconductors, are widely used in voltage ranges above 300 V and are especially popular in high-efficiency, high-speed power systems. In this paper, the size of the gate was adjusted to test the variation in the yield voltage characteristics by measuring the electric field concentration under the trench gate. After the experiment Synopsys' TCAD was used to analyze the efficiency of threshold voltage, on-state voltage drop, and breakdown voltage by measuring the P- region and its size under the gate.

• 식물분류학회지
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• 제51권4호
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• pp.363-371
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• 2021

Vicia bifolia Nakai (Fabaceae) and Cyperus compressus L. (Cyperaceae) have been ambiguous in terms of their distribution and taxonomic entities in Korea. The existence of these two taxa was confirmed when V. bifolia and C. compressus was found on Jellabuk-do, Gyeongsangnam-do, and Jeju-do. Vicia bifolia is similar to V. unijuga by having a pair of leaflets but is distinguished by the length of the petiole, the size and degree of longevity of the bracts, and the shape of the stipules. Cyperus compressus was found on Jeju-do, is similar to C. tenuispica, C. haspan, and C. flaccidus, but is distinguished by the branching pattern of the inflorescences and the size of scales and achenes. A description, differences from related species, a key to the taxa and photographs of Korean Vicia bifolia and Cyperus compressus are provided in this study.

• 한국광물학회지
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• 제14권2호
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• pp.85-98
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• 2001

콘크리트 구조물에 사용되는 골재의 화학적 안전성을 진단하는 방법 중의 하나인 암석기재학적 시험(ASTM C 295)에 관한 연구로서, 이 연구를 위하여 골재의 입도 분석, 피막 검사, 풍화 ·오염상태, 암석학적 기재, 그리고 알칼리-골재 반응성 광물 및 암석의 정성·정량적 분석을 실시하였다. 경남 울진군 매화천 유역 A, B 지역의 하천 골재에 대하여 암석기재학적 방법으로 검사한 결과 풍화상태는 F(신선) 등급과 WS(약간 풍화) 등급이며 골재의 피막과 오염 상태는 우려할 정도는 아니다. 알칼리-골재 반응 광물이나 구조적으로 취약한 암석이 함유된 골재는 매화천 A 지역 골재 전체의 26 wt.%, B 지역은 19 wt.%로 집계되는데 이는 양호한 골재로 볼 수 없기 때문에 화학적 방법과 몰탈바 방법으로 더욱 정밀한 시험을 거쳐 안전성이 확인되어야 한다.

• 융합정보논문지
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• 제10권12호
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• pp.31-38
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• 2020

전자전의 레이더 신호식별은 신호수신기가 생성한 PDW(Pule Description Word)를 분석해서 펄스반복 간격(PRI, Pulse Repetition Interval)을 인식하는 기술이다. 일반적으로 여러 개의 PDW를 수집해 한 번에 처리하는 배치처리 방식으로 PRI를 식별한다. 본 논문에서는 스트리밍 프로세스에 기초한 신호 특성 추출 알고리즘을 제안한다. 이 기술은 신호수신기에서 PDW를 생성할 때마다 PDW 군집이 형성되는지 조사하고, 레이더 펄스의 도착시간 차이(difference of TOA(Time of Arrival)) 히스토그램을 만들고, 집중도를 기반으로 프레임 PRI를 구하고, 스태거 단계 수를 결정한다. 실험에 의하여 군집의 크기가 증가함에 따라 안정된 인식 결과를 도출한다는 것을 입증했다.

• Korean Membrane Journal
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• 제7권1호
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• pp.1-18
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• 2005

The permeate flux decline due to membrane fouling can be addressed using a variety of theoretical stand-points. Judicious selection of an appropriate theory is a key toward successful prediction of the permeate flux. The essential criterion f3r such a decision appears to be a detailed characterization of the feed solution and membrane properties. Modem theories are capable of accurately predicting several properties of colloidal systems that are important in membrane separation processes from fundamental information pertaining to the particle size, charge, and solution ionic strength. Based on such information, it is relatively straight-forward to determine the properties of the concentrated colloidal dispersion in a polarized layer or the cake layer properties. Incorporation of such information in the framework of the standard theories of membrane filtration, namely, the convective diffusion equation coupled with an appropriate permeate transport model, can lead to reasonably accurate prediction of the permeate flux due to colloidal fouling. The schematic of the essential approach has been delineated in Figure 5. The modern approaches based on appropriate cell models appear to predict the permeate flux behavior in crossflow membrane filtration processes quite accurately without invoking novel theoretical descriptions of particle back transport mechanisms or depending on adjust-able parameters. Such agreements have been observed for a wide range of particle size ranging from small proteins like BSA (diameter ${\~}$6 nm) to latex suspensions (diameter ${\~}1\;{\mu}m$). There we, however, several areas that need further exploration. Some of these include: 1) A clear mechanistic description of the cake formation mechanisms that clearly identifies the disorder to order transition point in different colloidal systems. 2) Determining the structure of a cake layer based on the interparticle and hydrodynamic interactions instead of assuming a fixed geometrical structure on the basis of cell models. 3) Performing well controlled experiments where the cake deposition mechanism can be observed for small colloidal particles (< $1\;{\mu}m$). 4) A clear mechanistic description of the critical operating conditions (for instance, critical pressure) which can minimize the propensity of colloidal membrane fluting. 5) Developing theoretical approaches to account for polydisperse systems that can render the models capable of handing realistic feed solutions typically encountered in diverse applications of membrane filtration.

• Archives of Plastic Surgery
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• 제41권5호
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• pp.500-504
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• 2014

Background Skin cancer is the most prevalent cancer by organ type and referral accuracy is vital for diagnosis and management. The British Association of Dermatologists (BAD) and literature highlight the importance of accurate skin lesion examination, diagnosis and educationally-relevant studies. Methods We undertook a review of the relevant literature, a national audit of skin lesion description standards and a study of speciality training influences on these descriptions. Questionnaires (n=200), with pictures of a circular and an oval lesion, were distributed to UK dermatology/plastic surgery consultants and speciality trainees (ST), general practitioners (GP), and medical students (MS). The following variables were analysed against a pre-defined 95% inclusion accuracy standard: site, shape, size, skin/colour, and presence of associated scars. Results There were 250 lesion descriptions provided by 125 consultants, STs, GPs, and MSs. Inclusion accuracy was greatest for consultants over STs (80% vs. 68%; P<0.001), GPs (57%) and MSs (46%) (P<0.0001), for STs over GPs (P<0.010) and MSs (P<0.0001) and for GPs over MSs (P<0.010), all falling below audit standard. Size description accuracy sub-analysis according to circular/oval dimensions was as follows: consultants (94%), GPs (80%), STs (73%), MSs (37%), with the most common error implying a quadrilateral shape (66%). Addressing BAD guidelines and published requirements for more empirical performance data to improve teaching methods, we performed a national audit and studied skin lesion descriptions. To improve diagnostic and referral accuracy for patients, healthcare professionals must strive towards accuracy (a circle is not a square). Conclusions We provide supportive evidence that increased speciality training improves this process and propose that greater focus is placed on such training early on during medical training, and maintained throughout clinical practice.

• Applied Microscopy
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• 제29권3호
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• pp.275-280
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• 1999

Hypoxylon속은 자낭각을 지닌 갈색이나 진한 갈색의 목질, 또는 탄소질의 자좌를 형성하며, 자낭균류의 대표적인 목재 부후균으로 분류된다. 부후된 목재에서 발견된 국내 미기록종인 본 Hypoxylon moriforme를 국내에서는 최초로 발견하여 국내의 새로운 기록종으로 보고한다. Hypoxylon moriforme는 광학현미경, 주사전자현미경을 이용하여 미세구조학적으로 기술하였다. H. moriforme는 $7.5\sim9.0\times2.5\sim4.0{\mu}m$의 작은 자낭포자와 $75\sim130\times3\sim5{\mu}m$ 자낭을 가지고 있으며, 동북아시아에서 매우 다양하며 근접한 H. truncatum, 열대 및 아열대 지방에서 발견되는 유사한 H. bover 및 H. annulatum과 분류학적으로 비교, 동정하였다.

• 정보처리학회논문지C
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• 제18C권4호
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• pp.255-264
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• 2011

TV-Anytime은 XML을 PVR이나 방송서비스에 적용하기 위하여 서비스, 컨텐츠 정보 표현을 위한 스키마와 전송 프로토콜을 정의하여 많은 방송 규격에서 참조 문서로 활용되고 있다. 높은 확장성과 가독성에 비해 텍스트기반으로 정보를 기술하여 문서가 커지는 단점이 존재하며 이를 극복하기 위한 인코딩 알고리즘이 많이 제안되고 있다. 본 논문에서는 TVA 디스크립션을 전송하는 과정에서 문서의 크기를 최소화 할 수 있는 최적화 정보를 서버 단에서 반영하는 효율적인 인코딩 방식과 캡슐화 과정에서 색인 정보에 필요한 정보를 줄이고 정보를 빠르고 직관적으로 수신할 수 있는 인덱싱 방식을 제안한다.