• 제목/요약/키워드: B-unit

검색결과 2,501건 처리시간 0.029초

선박용 HVAC 시스템의 소음저감성능 평가 (Evaluation of Noise Reduction Performance of HVAC System for Ships)

  • 김상렬;김현실;김재승;김봉기;이성현
    • 한국음향학회지
    • /
    • 제29권8호
    • /
    • pp.497-503
    • /
    • 2010
  • 본 논문은 여객선용 HVAC 시스템 목업을 구축하여 HVAC 요소의 성능평가를 수행한 결과를 다루었다. 측정은 룸 유니트 (Room Unit), 소음기 등 6가지 종류에 대해 이루어졌으며 여러 유량에 대해 삽입손실을 측정하였다. 소음기 직경이 작고 유량이 클수록 유동소음이 커져서 소음저감효과를 방해하지만, 직경이 커질수록 유동소음의 효과는 작아지고 삽입손실은 최대 25 dB까지 나타남을 확인하였다. 디퓨저 형태의 룸 유니트는 대체로 삽입손실이 0 - 10 dB 이지만 노즐 형태는 삽입손실이 최대 -15 dB 까지 소음이 커질 수 있음을 확인하였다. 또한 덕트 배열에 따라 최대 2 dB 까지 실내소음이 차이날 수 있음을 보였으며 각 룸 유니트에 동일한 유량이 배출하도록 조절하는 것이 보다 낮은 소음레벨을 얻을 수 있음을 확인하였다.

경기도 소방재난본부에 소속된 두 구급대의 출동수요 분석 (An Analysis of Call Demands of Two Squads In Kyonggi Provincial fire and Disaster Headquarters)

  • 엄태환
    • 한국응급구조학회지
    • /
    • 제6권1호
    • /
    • pp.77-86
    • /
    • 2002
  • The purposes of this research which was conducted by surveying lost/added unit hours reports, unit hour demand analysis worksheets from prehospital care reports of two squads in Kyonggi Provincial Fire and Disaster Headquarters for 20 weeks (January 1, 2002 - May 20, 2002) are to get Unit Hour Utilizations. Call Demands such as Unit Hour Demand, Simple Average Demand, High Average Demand, Peak Average Demand, the High Actual Demand. The conclusions from this analysis were summarized as follows: (1) By revealing Unit Hour Produced 3223.9, Call Volume 964, Unit Hour Utilization 0.299 at the Squad A and Unit Hour Produced 3328.4, Call Volume 901, Unit Hour Utilization 0.271 at the Squad B induced Korean Squads to chance identification, definition, direction of Unit Hour Utilization. (2) By revealing Simple Average Demand 7.4 on Monday Tuesday, High Average Demand 9.6 on Tuesday Friday. Peak Average Demand 11.5 on Tuesday, the High Actual Demand 12 on Tuesday Wednesday at the Squad A and Simple Average Demand 6.8 on Sunday, High Average Demand 10.4 on Monday, Peak Average Demand 11.5 on Monday, the High Actual Demand 13 on Monday at the Squad B enabled Korean Squads to utilize System Status Management. (3) The Maximum Calls per Unit Hour were 115 for 23:00~23:59, the Minimum Calls per Unit Hour were 46 for 05:00~05:49 in two squads. The Maximum Calls per Unit Hour were 7.4 on Tuesday Saturday, the Minimum Calls per Unit Hour were 6.1 on Thursday at the Squad A. The Maximum Calls per Unit Hour were 7.3 on Monday Saturday, the Minimum Calls per Unit Hour were 5.6 on Thursday at the Squad B. (4) Analyzing demand for EMTs in the optimum emergency medical service of Korea, we have been able to utilize this Unit Hour Utilization in company with the established estimation methods such as international comparisons or the number of ambulances for scientific reasonable estimation. (5) These Call Demands which were limited to the demand time in this study will make us expect some following studies including demand time, demand time, demand map for Strategic Deployment.

  • PDF

직무 스트레스와 간호사가 인식하는 간호단위 관리자의 진성 리더십이 임상간호사의 재직의도에 미치는 영향 (Effect of Job Stress and Perception of Unit Managers' Authentic Leadership on the Clinical Nurses' Intention to Stay )

  • 이혜자;채덕희
    • 한국직업건강간호학회지
    • /
    • 제32권3호
    • /
    • pp.99-110
    • /
    • 2023
  • Purpose: This study examined the job stress and perception of unit managers' authentic leadership on clinical nurses' intention to stay in nursing. Methods: This descriptive cross-sectional study utilized self-administered questionnaires. The study recruited a convenience sample of 211 clinical nurses from threertiary hospitals in South Korea. The survey was conducted between July and August 2021. The collected data underwent hierarchical multiple regression analyses. Results: The regression analyses indicated that clinical nurses' intention to stay was significantly associated with job stress (B=-0.06, 95% CI [-0.09, -0.04]), six or more years of clinical practice (B=0.60, 95% CI [0.13, 1.07]), men (B=0.87, 95% CI [0.30, 1.44]), and being placed on their desired nursing unit (B=0.39, 95% CI [0.27, 0.76]). Intention to stay was not found to be associated with authentic leadership by the unit managers. Conclusion: It is essential to implement workplace health promotion programs to prevent and reduce job stress among nurses to retain proficient clinical nurses. Additionally, nursing workforce management strategies tailored to the specific sex and career path of nurses are necessary. Moreover, careful consideration should be given to nursing unit placements that align with the individual aptitudes of nurses.

분산이 적은 광 아이솔레이터에 관한 연구 (A study on the dispersion-free optical isolator)

  • 연제세
    • 한국광학회지
    • /
    • 제8권2호
    • /
    • pp.142-148
    • /
    • 1997
  • 분산이 적은 새로운 형태의 광 아이솔레이터 광학계를 제안하였으며, 이의 성능을 이론 및 실험적으로 검증하였다. 본 논문에서 제안한 광 아이솔레이터의 광학계는 2개의 쐐기 형상의 복굴절 소자와 패러데이 회전자, COLLIMATING UNIT, FOCUSING UNIT로 이루어졌다. 파장 1550 nm에서 성능시험 결과 아이솔레이션 40 dB 이상, 상입손실 0.55 dB 이하, 분산 0.02 ps 이하의 결과를 얻었다.

  • PDF

가변 특성을 갖는 디지털 TV 휘도신호 처리용 디지털 필터 설계 (Design of a digital filter with variable characteristics for a luminance signal processing of digirtal TV)

  • 왕종현;이해정;유영갑;조경록
    • 한국통신학회논문지
    • /
    • 제21권1호
    • /
    • pp.67-79
    • /
    • 1996
  • This paper presents a composite luminance signal processing system for NTSC, PAL and SECAM standards. Eaxh of the three standards employs its own specifications of subcarmier bandwidth and luminance signal waveform. The proposed system, compatible to the specifications of the three standard and B/W TV, implements variable freqneucy characteristics by controlling filter coefficients. The major features of the system are a luminance/chroma separation unit and an aperture compensation unit. The luminance/chroma separation unit employes a notch filter selection a trap freqneyc to atenuate unwanted color signals in luminance signal bands. The aperture compensation unit comprises two subunits, to provide clear color definition for each of the three standards: a primary compensation circuit and a variable compensation circuits. The proposed system yields a 40 dB gain from the chroma/luminance separation and a 10 dB gain from the aperture compensation unit.

  • PDF

Sesquicillin, an Extracellular Matrix Adhesion Inhibitor, Inhibits the Invasion of B16 Melanoma Cells In vitro

  • Lee, Ho-Jae;Chun, Hyo-Kon;Chung, Myung-Chul;Lee, Choong-Hwan;Kho, Yung-Hee
    • Journal of Microbiology and Biotechnology
    • /
    • 제9권1호
    • /
    • pp.119-121
    • /
    • 1999
  • Tumor cell interaction with the extracellular matrix is defined as the critical event of tumor invasion that signals the initiation of a metastatic cascade. Sesquicillin has been identified as an inhibitor of melanoma cell adhesion to the components of the extracellular matrix (ECM) in cultured broth of fungal strain F60063. Sesquicillin strongly inhibited the adhesion of B16 melanoma cells to laminin, fibronectin, and typeIV collagen. It also inhibited B16 melanoma cell invasion of reconstituted basement membrane Matrigel in vitro in a dose-dependent manner. These results suggest that sesquicillin is a new class of nonpeptidic ECM adhesion inhibitor having anti-invasive activity.

  • PDF

개선된 Unit 보강 알고리즘을 이용한 강안정화 제어기 설계 (Strong Stabilization Controller Design Using Advanced Unit Interpolation algorithm)

  • 윤한오;신창훈;박홍배
    • 전자공학회논문지B
    • /
    • 제31B권8호
    • /
    • pp.31-38
    • /
    • 1994
  • This paper presents an improved interpolation algorithm which enables to find a unit function in $H^{\infty}$. From the proposed algorithm the interpolation problem on the infinity point with multiplicity can be solved. This is based on the DPL algorithm the acquired unit function has low order and can be directly applied to strong/simultaneous stabilization problem in control systems. Finally, we verify that poles of transfer function of closed-loop system exist in stable region while investgating internal stability.

  • PDF

Temperature Independent Biasing을 사용한 DTV 중계기용 100Watt급 단위 전력증폭기의 구현 (The 100Watt Unit Power Amplifier Using Temperature Independent Biasing for DTV Repeater Application)

  • 이영섭;전중성;이석정;예병덕;홍창희
    • 한국항해항만학회지
    • /
    • 제26권2호
    • /
    • pp.215-220
    • /
    • 2002
  • 본 논문에서는 DTV 중계기용 Temperature Independent Biasing을 이용한 100 watt급 단위 전력증폭기를 설계한 후, 제작하였다. $20^{\circ}C$에서 $100^{\circ}C$까지의 온도변화에 대하여 단위 전력증폭기의 DC 동작점은 능동 바이어스에 의해서 고정되며, 증폭기의 소모전류의 변화량이 0.6A 이하의 우수한 특성을 얻었다. 제작된 단위 전력증폭기는 12dB 이상의 이득, $\pm$0.5dB 이하의 이득 평탄도, DTV 중계 주파수범위(470-806 MHz)에 걸쳐 15dB 이하의 입.출력 반사손실을 나타내었다. 100 Watt 단위 전력증폭기는 출력 전력이 100 watt일 때 2MHz의 오프셋에서 32dBc 이상의 상호 변조 왜곡(IMD)을 나타내었다.

밀기울배지를 이용한 Bacillus natto ${\alpha}-Amylase$ 생산 (${\alpha}-Amylase$ production of Bacillus natto IAM 1212 in the wheat bran medium)

  • 김광;박인호;선우양일
    • KSBB Journal
    • /
    • 제6권2호
    • /
    • pp.143-146
    • /
    • 1991
  • 세균액화형의 ${\alpha}-amylase$의 공업적 생산의 효율성을 높이기 위한 연구의 일환으로 제분공장과 도정공장의 분산물인 밀기울과 쌀겨를 이용하여 배양배지를 조성하고 B. subtilus와 A. oryzae 및 B. natto를 배양한 후 액화형 ${\alpha}-amylase$의 활성을 조사한 결과 B. subtilus와 A. oryzae의 경우 순수배지와 비교하였을 때 큰 차이가 없었으나 B. natto의 경우 외밀기울에서 액화활성이 다른 대구조에 비하여 크게 나타났는데 순수 배지를 이용한 액화활성은 crude enzyme에서 27.3 unit/ ml이고, 최종 액화 활성은 1,255.8u / ml인데 반해 외밀기울을 이용한 액화 활성은 crude enzyme에서 256.0 unit/ ml이고, 최종 액화 활성은 10,700 unit 이었으며 최적 배양온도는 $37^{\circ}C$이며 최적 배양액 pH는 6.8이었다. 그리고 정제된 효소의 분자량은 34,000dalton이었다. 이상의 결과로 보아 밀거울이 ${\alpha}-amylase$의 공업적 생산을 위한 저렴한 기질로 사용될만한 가치가 있다고 사료된다.

  • PDF