• 제목/요약/키워드: minority minority

검색결과 782건 처리시간 0.032초

중국 소수민족의 의상을 재해석한 패션디자인 연구 (Fashion Design Studies on Reinterpretation of Chinese Ethnic Minority Costumes)

  • 장이;김숙진
    • 한국의상디자인학회지
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    • 제13권2호
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    • pp.175-183
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    • 2011
  • Based on an investigation of Miao ethnic group costumes, this research focuses on redesigning and reinterpreting of the Miao costume. The results are summarized as follows. According to the constitution of the clothes, the decorative parts and the way people wear them, women's clothing can be divided into five categories: Sangseohyeong, Geomjungnamhyeong A, Geomjungnamhyeong B, Cheongeomjeonhyeong, Haenamhyeong. Miao consists of straight lines with creases for both skirts and trousers. With the excess part of the belt or apron, X-shape and H-shape are formed. There are three basic decorative patterns: geometric patterns, animal patterns and plant patterns. In addition, there are three color values: warm, cool and dark. Silver Jewelry plays such an important role in the Miao Costume that the process of the production is also very special for the Chinese national dress. According to the features of the five types of Miao, then redesign and re-interpreted of them.

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수소화된 비정질 실리콘 박막을 이용한 웨이퍼 패시베이션 특성 연구 (A study on wafer surface passivation properties using hydrogenated amorphous silicon thin film)

  • 이승직;김기형;오동해;안황기
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2010년도 추계학술대회 초록집
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    • pp.46.1-46.1
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    • 2010
  • Surface passivation of crystalline silicon(c-Si) surface with a-Si:H thin films has been investigated by using quasi-steady-state photo conductance(QSSPC) measurements. Analyzing the influence of a-Si:H film thickness, process gas ratio, deposition temperature and post annealing temperature on the passivation properties of c-Si, we optimized the passivation conditions at the substrate temperature of $200-250^{\circ}C$. Best surface passivation has been obtained by post-deposition annealing of a-Si:H film layer. Post annealing around the deposition temperature was sufficient to improve the surface passivation for silicon substrates. We obtained effective carrier lifetimes above 5.5 ms on average.

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PC1D 기반의 2스텝 도핑을 통한 실리콘 태양전지의 최적화

  • 김영필;정우원;이준신
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 추계학술대회 논문집
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    • pp.256-256
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    • 2009
  • This paper presents a proper condition to achieve above 17 % conversion efficiency using PC1D simulator. Crystalline silicon wafer with thickness of $240{\mu}m$ was used as a starting material. Various efficiency influencing parameters such as rear surface recombination velocity and minority carrier diffusion length in the base region, front surface recombination velocity, junction depth and doping concentration in the Emitter layer. Among the investigated variables, we learn that 2nd doping concentration as a key factor to achieve conversion efficiency higher than 17 %.

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광통신용 GaAs/(Ga, Al)As DH-LED의 최적 주파수 응용에 대한 연구 (The Optimum Frequency Response of GaAs/(Ga, Al) As DH-LED for Optical Communication)

  • 오환술;김영권
    • 대한전자공학회논문지
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    • 제21권3호
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    • pp.60-65
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    • 1984
  • 본 논문은 광통신용 광원의 가장 중요한 설계변수인 주파수응답의 최적화를 위하여 대칭 CaAs/(Ca, Al)As DH-LED를 모델로 채택하여 다이오드의 설계변수들인 활성층의 불순물농도, 활성층폭, 소수캐리어수명, 금지대폭, 굴절률, 공간전하용량, 주입전류밀도 등의 물리적 제인자들의 백호관계를 체계적으로 정립하여 컴퓨터 시뮬레이션에 의한 최적설계변수치들을 설정하는데 그 목적이 있다.

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Unconventional Answers to Unprecedented Challenges: The Swedish Experience During the COVID-19 Outbreak

  • Valeriani, Giuseppe;Vukovic, Iris Sarajlic;Mollica, Richard
    • Journal of Preventive Medicine and Public Health
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    • 제53권4호
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    • pp.233-235
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    • 2020
  • Since its early stages, the coronavirus disease 2019 (COVID-19) pandemic has posed immense challenges in meeting the public health and healthcare and social care needs of migrants. In line with other reports from United Kingdom and United States, data from Sweden's health authority show that migrants have been disproportionately affected by COVID-19. Following the World Health Organization's statements, as well as the European Public Health Association's call for action, several centres in Sweden's most populated areas have activated tools to implement national plans for community outreach through initiatives targeting migrants and ethnic minority groups. Unconventional means should be promoted to mitigate the impact of COVID-19 on migrants and the health of the public at large.

Transient Analysis of PT-IGBTs at High Temperature

  • Ryu Sehwan;Lee Hokil;Ahn Hyungkeun;Han Deuk-Young
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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    • pp.39-43
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    • 2001
  • In this paper, excess minority carrier distribution in drift and buffer layers and accumulated charges for PT IGST have been, for the first time, analytically expressed with different transient times, lifetimes and temperatures. Furthermore those parameters are also expressed with temperature to predict the transient response which are critical to the real operation. Active base region has been chosen to extract the temperature dependency of the device by including the buffer layer which is important but neglected due to the complexity up to now.

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An Analytical Transient Model for NPT IGBT

  • Ryu, Se-Hwan;Ahn, Hyung-Keun;Han, Deuk-Young
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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    • pp.26-30
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    • 2001
  • In this paper, transient characteristics of IGBT has been analytically solved to express the excess minority carrier distribution in active base region and the output voltage. Non-Punch Through(NPT) structure has been selected to prove the validity of the model. It is based on the equivalent circuit of MOSFET which supplies a low gain and a high level injection to the base of BJT. None of the quasi static conditions have been assumed to trace the transient characteristics. The basic elements of the model have been derived from the ambipolar transport theory. Theoretical predictions of the output voltages have been obtained with different lifetimes and compared with experimental and theoretical results available in the literature. From the analytical approach, good agreement has been obtained to provide reliable and fast output of the device.

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새로운 ZVZCS PWM Boost 컨버터 (A Novel ZVZCS PWM Boost Converter)

  • 김태우;진기호;강안종;김학성
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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    • pp.327-331
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    • 2003
  • This paper proposes a novel ZVZCS-PWM Boost Converter. It enables the main switch to be turned on and off with both zero voltage and zero current and the auxiliary switch to be turned on and off with ZCS, the rectify diode to be turned on and off with ZVS. Moreover, this converter is suitable for not on]y minority carrier device but also majority carrier device. The auxiliary resonant circuit of the proposed boost converter is placed out the main power path, therefore, there are no voltage/current stresses on the main switch and diode. The operation of the proposed boost converter is explained and analyzed theoretical and experimentally, from a prototype operating at 100kHz, with an input voltage rated at 50V.

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Epitaxial에 의한 Si epi층의 케리어 수명과 P-N접합의 이상전도현상 (Carrier Lfetime and Anormal Cnduction Penomena in Silicon Epitaxial Layer-substrate Junction)

  • 성영권;민남기;김승배
    • 전기의세계
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    • 제26권5호
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    • pp.83-89
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    • 1977
  • This paper described the minority carrier lifetime in Si epitaxial layer, and also the voltage (V) versus current (I) characteristics of high resistivity Si epitaxial layer0substrate junction. The measured lifetime in Si epi-layer was much shorter than in bulk, and the temperature dependence of lifetime was found to agree well with Shockley-Read model of recombination which applies to high resistivity n-type materials. The V-I curve showed; an ohmic region (I.var.V), a sublinear region (I.var.V$^{1}$2/), a space charge limited current region (I.var.V$^{2}$), and finally a negative resistance region. We investigated these phenomena by the theory of the relaxation semiconductor.

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Czochralski 법으로 성장시킨 실리콘 단결정 Wafer에서의 Gettering에 관한 연구 (A Study on the Gettering in Czochralski-grown Single Crystal Silicon Wafer)

  • 양두영;김창은;한수갑;이희국
    • 한국세라믹학회지
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    • 제29권4호
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    • pp.273-282
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    • 1992
  • The effects of intrinsic and extrinsic gettering on the formation of microdefects in the wafer and on the electrical performance at near-surfaces of three different oxygen-bearing Czochralski silicon single crystal wafers were investigated by varying the combinations of the pre-heat treatments and the phosphorus diffusion through the back-surface of the wafers. The wafers which had less than 10.9 ppma of oxygen formed no gettering zones irrespective of any pre-heat treatments, while the wafers which had more than 14.1 ppma of oxygen and were treated by Low+High pre-heat treatments generated the gettering zone comprising oxygen precipitates, staking faults, and dislocation loops. The effects of extrinsic gettering by phosphorus diffusion were evident in all samples such that the minority carrier lifetimes were increased and junction leakage currents were decreased. However, the total gettering effects among the different pre-heat treatments did not necessarily correspond to the gettering structure revealed by synchrotron radiation section topograph.

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