• 제목/요약/키워드: bi-jeung

검색결과 39건 처리시간 0.031초

공침법을 이용한 $Bi_2Te_3$ 열전재료의 제조 (Preparation of $Bi_2Te_3$ Thermoelectric Materials by Co-precipitation Method)

  • Kim, Dong-Hwan;Im, Hee-Joong;Je, Koo-Chul;Kang, Young-Jin;Ahn, Jeung-Sun;Tadaoki Mitani;Nam, Tae-Hyun;Shim, Young-Jae
    • 한국재료학회:학술대회논문집
    • /
    • 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
    • /
    • pp.167-167
    • /
    • 2003
  • 현대 산업이 발전함에 따라 전자부품의 초소형화, 고성능화가 요구되어지고 있으며, 이러한 점에 부응하기 위하여 Pottier 효과를 이용하여 국부냉각이 가능한 열전재료에 대한 많은 연구가 이루어지고 있다. 열전재료에는 사용온도 영역에 따라 여러 종류가 있지만, Bi-Te계 열전재료는 상온영역에서 가장 성능지수(Z=$\alpha$$^2$$\sigma$/$textsc{k}$, $\alpha$는 Seebeck 계수, $\sigma$는 전기전도도, $textsc{k}$는 열전도도)가 높아 각종 냉각소자로서 사용되어 지고 있다. 하지만, 초소형 전자부품의 국부냉각을 위해서는 성능지수의 향상, 특히, 저온 영역에서의 성능지수의 향상이 요구되고 있다. 본 연구에서는 Bi-Te계 열전재료의 성능지수를 향상시키기 위하여, 열전도도의 저하에 의한 성능지수의 향상을 연구목적으로 하였다 열전도도는 전자에 의한 열전도도(K$_{e}$)와 phonon에 의한 열전도도(K$_{p}$)로 이루어지며, 전기전도도에 큰 영향을 미치지 않는 결정립 사이즈영역에서 결정립의 크기를 미세화 하면, 결정입계에서의 phonon의 산란이 증가하여 phonon에 의한 열전도도를 저하시킴으로서 성능지수의 향상이 기대된다. 따라서 본 연구에서는 나노사이즈 분말의 제조에 많이 이용되며 입자크기의 조절이 용이한 공침법을 이용하여 Bi-Te계 열전재료 분말을 제조하고 열전재료에의 적용가능성을 검토하였다.

  • PDF

뇌졸중 후 중추성 통증으로 인한 좌반신비증 치험 1례 (A Case Report of Central Post-Stroke Pain Patient Treated by Moxibustion Therapy)

  • 이미림;이유리;민경동;조기호;문상관;정우상
    • 대한중풍순환신경학회지
    • /
    • 제16권1호
    • /
    • pp.35-40
    • /
    • 2015
  • ■ Objectives The purpose of this clinical study is to evaluate the effect of moxibustion on a patient with left side paresthesia induced by central post-stroke pain. ■ Methods A patient with left side paresthesia diagnosed with central post-stroke pain was treated with moxibustion, herbal medication, acupuncture, electro-acupuncture(EA). Then we evaluated the improvement by Mcgill pain score and Questionnaire of BiJeung. ■ Results Decrease of Mcgill pain score, Questionnaire of BiJeung were observed after the moxibustion treatment. ■ Conclusion This study proved the effect of moxibustion treatment on left side paresthesia due to central post-stroke pain.

  • PDF

단결정 반금속 비스무스 단일 나노선의 Shubnikov-de Haas 진동 (Shubnikov-de Haas Oscillations in an Individual Single-Crystalline Semimetal Bismuth Nanowire)

  • 김정민;함진희;심우영;이경일;전계진;정원용;이우영
    • 한국재료학회지
    • /
    • 제18권2호
    • /
    • pp.103-106
    • /
    • 2008
  • The magneto-transport properties of an individual single crystalline Bi nanowire grown by a spontaneous growth method are reported. A four-terminal device based on an individual 400-nm-diameter nanowire was successfully fabricated using a plasma etching technique that removed an oxide layer that had formed on the surface of the nanowire. Large transverse ordinary magnetoresistance (1401%) and negative longitudinal ordinary magnetoresistance (-38%) were measured at 2 K. It was observed that the period of Shubnikov-de Haas oscillations in transverse geometry was $0.074^{T-1}$, $0.16^{T-1}$ and $0.77^{T-1}$, which is in good agreement with those of bulk Bi. However, it was found that the period of SdH oscillation in longitudinal geometry is $0.24^{T-1}$, which is larger than the value of $0.16^{T-1}$ reported for bulk Bi. The deviation is attributable to the spatial confinement arising from scattering at the nanowire surface boundary.

Electronic Structures of Graphene Intercalated by Oxygen on Ru(0001): Scanning Tunneling Spectroscopy Study

  • Jang, Won-Jun;Jeon, Jeung-Hum;Yoon, Jong-Keon;Kahng, Se-Jong
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
    • /
    • pp.114-114
    • /
    • 2011
  • Graphene is the hottest topic in condensed-matter physics due to its unusual electronic structures such as Dirac cones and massless linear dispersions. Graphene can be epitaxially grown on various metal surfaces with chemical vapor deposition (CVD) processes. Such epitaxial graphene shows modified electronic structures caused by substrates. In the method for removal of the effect of substrate, there are bi, tri-layer graphene, gold intercalation, and oxygen intercalation. Here, We will present the changes of geometric and electronic structure of graphene grown on Ru(0001) by oxygen intercalation between graphene and Ru(0001). Using Scanning tunneling microscopy (STM) and spectroscopy (STS), we observed the aspect that the band gap features near the fermi level of graphene on Ru(0001) system is shifted and narrow. Based on the observed results, two effects by intercalated oxygen were considered.

  • PDF

Suppurative arthritis 환자(患者) 1례(例)의 한(韓)·양방(洋方) 겸치를(兼治)를 통(通)한 임상적(臨床的) 고찰(考察) (Clinical Study of Oriental-Western collaborative medical treatment on 1 case of patient with Suppurative Arthritis)

  • 하치홍;조명래
    • Journal of Acupuncture Research
    • /
    • 제17권3호
    • /
    • pp.277-285
    • /
    • 2000
  • By process of treatment for a case which diagnosed as suppurative arthritis and admitted from the 5th, October, 1999 to the 15th, November, 1999, the results are as follows. Method & Results : In the earlier days of admission, this patient was diagnosed as damp-heat(濕熱) and medicated Cheongyeolsaseup-tang(qingrexieshi-tang). As the result, heating, pain in both knees and heating in both lmees are improved. In the later days of admission, this patient was diagnosed as impairment of the liver and kidney(肝腎虛損) and medicated Samgi-eum(sanqi-yin). As the reslut, weakness in lower limbs is improved. Conclusion : I consider that the rate of recovery for other infectious diseases including suppurative arthritis can be maximized by accumulation of clinical experiences and continuous research through both western medical treatment and oriental medical treatment.

  • PDF

Bazooka balun을 이용한 PCS 중계기용 슬롯 안테나의 설계 및 구현 (Design and Implementation of a Slot Antenna with Bazooka Balun for PCS Repeater)

  • 최원준;김채영;장병찬;박정근
    • 대한전자공학회:학술대회논문집
    • /
    • 대한전자공학회 2007년도 하계종합학술대회 논문집
    • /
    • pp.105-106
    • /
    • 2007
  • A slot antenna with bazooka balun is designed and implemented for PCS repeater. The proposed antenna improved the return loss and radiation pattern of the slot antenna as combining with the bazooka balun. The antenna was designed by using 3D simulations program, MWS (Microwave Studio). The test result of the slot antenna shows that the return loss is under -10 [dB] for all frequency bands of interests in PCS and maximum gain is about 5.59 [dBi]. And the antenna also shows omni-directional radiation pattern.

  • PDF

이명(耳鳴)의 양상에 따른 장상적(臟象的) 상관(相關) 분석 및 변증(辨證) 형태별 삶의 질에 관한 연구 (A Study on the quality of Life by jansang(臟象)'s relational analysis and Byunjeung(辨證)'s type according to Tinnitus's aspect)

  • 김경준
    • 한방안이비인후피부과학회지
    • /
    • 제30권3호
    • /
    • pp.20-30
    • /
    • 2017
  • Background : Tinnitus is common disorder with many possible causes and a symptom of many different diseases but has no effective treatment. Approximately 20% of tinnitus patients experience the disorder to a degree that their quality of life and productivity are impaired. Objectives : 1. Through symptoms of tinnitus, we tried to find out the relationship of Heo-sil(虛實) and Jang bu byun jeung(臟腑辨證). 2. By testing THI, we tried to evaluate the quality of life between high-grade tiny noise and low-grade roar tinnitus patients group. Methods : 34 patients were recruited in this study who was ill with tinnitus. They wrote out the questionnaire about tinnitus and the tinnitus Handicap Inventory(THI). Results : 1. The vast majority of high-grade tiny noise patients are Heojeung(虛症). 2. The vast majority of low-grade roar patients are Siljeung(實症). 3. The number of patients with intermittent and persistent tinnitus is similar. 4. In high-grade tiny noise, Sin jung hyu son type(腎精虧損型) patients are less comfortable with quality of life than Bi wi heo yak type(脾胃虛弱型) patients. 5. Low-grade roar patients are less comfortable with quality of life than high-grade tiny noise atients Conclusions : Jang bu byun jeung(臟腑辨證) and Distinguishing between Heo(虛) and Sil(實) is expected to have positive effects on tinnitus treatment.

과산화수소증기 시스템을 이용한 야전용 천막 내 Geobacillus stearothermophilus 아포 제독 (Decontamination of Interior of Field Tent Employed Geobacillus stearothermophilus Spores using a Hydrogen Peroxide Vapor System)

  • 윤성녀;김윤기;정정훈;유현상;민경률;김민철;김세계;류삼곤
    • 한국군사과학기술학회지
    • /
    • 제19권5호
    • /
    • pp.669-674
    • /
    • 2016
  • The purpose of this study is to demonstrate the suitability of hydrogen peroxide($H_2O_2$) vapor system for platform interior decontamination. Geobacillus stearothermophilus biological indicator(BI) strips and a field tent were used as a biological simulant and as a simulated platform, respectively. Decontamination was performed based on injection rates and tent sizes with exposure time 60 minutes. We standardized the conditions for the field tent decontamination : 8.0 g/min for $30m^3$($H_2O_2$ vapor concentration of 150~500 ppm, relative humidity of 50 %) and 12.0 g/min for $60m^3$($H_2O_2$ vapor concentration of 250~400 ppm, relative humidity of 55 %). Thus we suggest the system is one of the possible candidates for decontamination of platform interiors.

LTCC 공법을 사용한 Cellular/SDMB 안테나-다이플렉서 모듈 (Antenna-Diplexer Module for Cellular/SDMB Band Using LTCC Technology)

  • 하정욱;장기훈;윤영중
    • 한국전자파학회논문지
    • /
    • 제18권7호
    • /
    • pp.774-783
    • /
    • 2007
  • 본 논문은 Cellular 대역과 SDMB(Satellite Digital Multimedia Broadcasting) 대역에서 동작하는 무선 통신 시스템을 위한 송수신 전치단의 소형 안테나-다이플렉서 모듈을 설계하고 구현하는 방법을 제안한다. 제안된 모듈은 이중 공진 안테나와 다이플렉서로 구성되고, 저 손실과 소형화를 동시에 달성하기 위해 다층의 LTCC(Low Temperature Co-fired Ceramic) 기술을 이용하여 제작되었다. 이중 공진 안테나는 소형화를 위해 미앤더 라인을 사용하였고, 임피던스 매칭을 쉽게 이루기 위해 IFA(Inverted-F Antenna) 구조를 응용하여 설계하였으며, 간단한 구조를 지니면서 사양을 만족하는 이득과 대역폭을 갖는다. 다이플렉서는 저역 통과 필터 및 고역 통과 필터를 결합하여 설계되었고, 이들 사이의 상호 간섭을 줄임으로써 높은 격리도를 얻을 수 있었다. 제작된 모듈의 크기는 $27.5{\times}12.0{\times}2.2mm$이고, $813{\sim}902MHz,\;2,586{\sim}2,655MHz$의 동작 주파수 대역과 -1.96 dBi(cellular band), -5.43 dBi(SDMB band)의 이득이 측정되었다. 주파수 응답 특성과 방사 특성이 분석되었다.

WLAN대역의 듀얼 역-F형 내부 안테나 설계에 관한 연구 (A study on the design of an Dual Inverted-F Internal Antenna for the WLAN`s Band)

  • 강정진;강서;정성일;김완식;이종악
    • 전기전자학회논문지
    • /
    • 제7권2호
    • /
    • pp.223-229
    • /
    • 2003
  • 본 논문에서는 2.4GHz와 5.8GHz 대역의 무선 랜카드에 사용되는 듀얼 역-F형 내부 안테나의 설계 값에 따른 안테나 특성을 분석하였다. 노트북용 WLAN card의 PCB 기판에 인쇄된 형태로 설계하여 안테나의 길이, 단락 스터브의 두께, 피드선과 단락 스터브 사이의 간격, 안테나와 접지면 사이의 간격, 안테나의 두께 및 기판의 두께와 기판의 유전율에 따른 특성 변화를 연구하였다. 설계 값에 따른 특성변화 그래프로부터 설계 값을 튜닝하여 최적의 안테나를 설계하였다. 설계된 안테나는 VSWR이 1.6과 1.14이며, 주파수 대역폭은 170MHz와 500MHz 이며, 최대이득 3.5dBi 의 값을 얻었다.

  • PDF