• 제목/요약/키워드: modulators

검색결과 337건 처리시간 0.039초

반도체 스위치기반 펄스전원 기술 개발 및 응용 (Solid State Pulsed Power Modulator and Its Application)

  • 류홍제;장성록
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 2015년도 전력전자학술대회 논문집
    • /
    • pp.193-194
    • /
    • 2015
  • In this paper, the solid state pulsed power modulator developed in KERI, which is based on IGBT technologies are overviewed. During last ten years, several kinds of solid state modulators were developed in KERI such as IGBT stacks with step up transformer, full IGBT stack based marx generator, modified IGBT marx generator and high repetitive solid state modulator. Basic principle of the design is described and each pros and cons are compared. KERI's solid state pulsed power modulators has lot of advantages for industrial pulsed power application focused on everlasting life cycle and high repetitive, and shows superior arching protection ability.

  • PDF

High Power Coherent Beam Combining Setup Using Modified Cascaded Multi-dithering Technique

  • Ahn, Hee Kyung;Lee, Hwihyeong;Kong, Hong Jin
    • Current Optics and Photonics
    • /
    • 제2권5호
    • /
    • pp.431-435
    • /
    • 2018
  • A modified setup of a CMD technique for high power coherent beam combining was presented to address an issue of low damage threshold of electro-optic modulators. The feasibility of the modified setup was demonstrated by combining eight fiber beams, and it was successfully performed with ${\lambda}/44$ of residual phase error and 100 Hz of control bandwidth. It is expected that the modified CMD setup facilitates ultra-high power coherent beam combination without a limitation caused by the low damage threshold of electro-optic modulators.

Natural Modulators of Estrogen Biosynthesis and Function as Chemopreventive Agents

  • Bhat, Krishna P.L.;Pezzuto, John M.
    • Archives of Pharmacal Research
    • /
    • 제24권6호
    • /
    • pp.473-484
    • /
    • 2001
  • There is clearly a need for novel breast cancer chemopreventive agents with enhanced potency and specificity with tittle or no side effects. To this end, several new chemical moieties have been synthesized or isolated from natural sources. In this reviewal we have described some agents currently in use or under development for treatment or prevention of breast cancer, as well as our own strategies for the discovery of natural product modulators of estrogen biosynthesis and function. In particulars bioassay-guided fractionation of active plant extracts is a unique method for identifying agents with novel mechanisms of action, some of which should be useful for prevention of human cancer. Further, with the advent of combinatorial chemistry and high throughput screening, even greater progress may now be expected with natural product leads.

  • PDF

Incoherent Frequency 12-tupling Microwave Signal Generation Scheme Based on Cascade Modulators

  • Teng, Yichao;Zhang, Pin;Xu, Xin;Zhang, Baofu
    • Current Optics and Photonics
    • /
    • 제5권4호
    • /
    • pp.466-476
    • /
    • 2021
  • Frequency-multiplication technology based on microwave photonic principles can be used to generate microwave and millimeter wave signals with a wide frequency tuning range. However, the existing cascaded external modulation frequency-tupling scheme needs to ensure the phase coherence of the modulated Radio Frequency (RF) signal, while the phase modulation directly limits the frequency tuning range of the external modulation frequency multiplication. In this paper, a novel approach for generating an incoherent frequency 12-tupling signal with cascade modulation is proposed. The structure of cascaded dual-parallel Mach-Zehnder modulators can generate a frequency 12-tupling signal. The proposed structure uses no filter or phase control of the RF driving signal. Microwave photonic frequency-tupling was realized under incoherent conditions. Software simulations and experiments validated the proposed structure and proved that it can generate frequency 12-tupling microwave signals under incoherent conditions. Both the frequency range and reliability of the frequency-tupling system has been improved by the proposed structure.

APEC SEN Mental Health Training Curriculum for Seafarers across the APEC Region

  • 최승희
    • 한국항해항만학회:학술대회논문집
    • /
    • 한국항해항만학회 2022년도 춘계학술대회
    • /
    • pp.359-360
    • /
    • 2022
  • In light of the unprecedented occupational health and safety concerns that have been raised in the wake of the COVID-19 pandemic, the importance of seafarers' mental health has been significantly underlined. Despite the fact that there has been a significant amount of research on the psychological threats of seafarers' mental health, mutual cooperative actions on this issue have not been properly coordinated among seafarers' relevant bodies and stakeholders in APEC region. This paper introduces the APEC SEN's initiatives that have been undertaken to improve the mental health of seafarers, in collaboration with medical professionals, seafarers' unions, maritime administrations, and other stakeholders, through the development of training programmes and materials for both seafarers and modulators, resulting in a more effective approach to mental healthcare promotion.

  • PDF

Liquid Crystal Spatial Light Phase Modulator and its Applications

  • Hara, Tsutomu
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 한국정보디스플레이학회 2002년도 International Meeting on Information Display
    • /
    • pp.939-942
    • /
    • 2002
  • The optically addressed and electrically addressed spatial phase only light modulators without pixelized structures have been developed. A sufficient phase modulation capability and a high diffraction efficiency of these devices are useful for practical applications.

  • PDF

Multidrug-Resistance Modulators from Medicinal Plants

  • Lee, Jung-Joon;Kim, Se-Eun
    • 한국응용약물학회:학술대회논문집
    • /
    • 한국응용약물학회 1998년도 Proceedings of UNESCO-internetwork Cooperative Regional Seminar and Workshop on Bioassay Guided Isolation of Bioactive Substances from Natural Products and Microbial Products
    • /
    • pp.44-51
    • /
    • 1998
  • PDF

Environmental Mutagens-Detection, and Modulation of Their Activities

  • Hayatsu, Hikoya
    • Archives of Pharmacal Research
    • /
    • 제11권1호
    • /
    • pp.1-6
    • /
    • 1988
  • The use of blue cotton for detecting polycyclic aromatic mutagens in environmental samples (foods, human excretions, river water, etc) is reviewed. Since the invention of blue cotton has its origin in studies of mutagen modulators, these studies are also briefly reviewed.

  • PDF