• Title/Summary/Keyword: Space-charge field

Search Result 172, Processing Time 0.026 seconds

A Study on Public Property of the Regional Museum Design- Focused on the 21st Century Museum of Contemporary Art, Kanazawa, Ishikawaken in Japan - (지역 미술관디자인의 공공성에 관한 연구 - 일본 석천현 금택 21C 현대미술관을 대상으로 -)

  • Son Kwang-Ho;Kim Kang-Sub
    • Korean Institute of Interior Design Journal
    • /
    • v.14 no.6 s.53
    • /
    • pp.177-184
    • /
    • 2005
  • The 21st Century Museum of Contemporary Art, Kanazawa as a regional public culture facility is the place where it is possible to think over the roles and meanings of a museum. The urn of this research is to provide information for exploring a desirable direction of the design of a regional museum by analyzing the architectural meanings and public property of the 21st Century Museum of Contemporary Art, Kanazawa. In addition, we arranged the totes and meanings of a regional museum and the concept of the public property in architecture. We also analyzed the architectural quality and the expression of the public property in this museum, as well as the value and meaning of a museum through field researches. The results of this research are as follows. First, this museum breaks with the existing stereotyped Idea to be a space open to the citizens. It secures a wide public space and provides the convenience of access and every facility for citizens. Second, the floor plan is divided into the interchanging area for citizens and an exhibition area; the outskirts of the inside of the museum are planned to be used free of charge for an interchanging space of citizens as a public-owned space of citizens. Third, the public-owned space of citizens includes a citizen exhibition hall, an art library, a kids studio and rest space, which ate all designed lot everyone to enjoy freely. Last, the exterior shape of the museum is simple but harmonize with the surroundings. It has an unique shape showing the local identity, and its most special properties are the convenience of access, introduction of a free space inside, and security of a huge space for children and citizens.

Development of Horizontal Locomotion Robot using Rail Mechanism for H-beam Structure (H-빔 구조물에서의 레일을 이용한 수평주행로봇 개발)

  • Kim, Jong Heon;Jeon, Minseok;Jeon, Kyungtae;Lee, Sang Hoon;Hong, Daehie
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.30 no.4
    • /
    • pp.421-426
    • /
    • 2013
  • Nowadays in building construction field, workers become aged and avoid dirty, difficult, and dangerous work. Above all, a person who is in charge of beam assembling work in high and narrow space just relies on safety belt. So these workers should be highly trained. This paper deals with a new locomotion robot that can take this in charge, which will be able to provide less labor costs, less time to build a building and safer environments for workers. The geometric features of steel structure in building construction were carefully analyzed and developed a locomotion mechanism optimized to it. The robot was designed to be rugged, strong, and fast rather than having excessive mobility. Feasibility of the developed robot was verified through experiments.

Efficiency of the Hybrid-type Air Purifier on Reducing Physical and Biological Aerosol (복합식 공기청정기의 물리적 및 생물학적 입자상 물질의 제거 효과)

  • Kim, Ki-Youn;Kim, Chi-Nyon;Kim, Yoon-Shin;Roh, Young-Man;Lee, Cheol-Min
    • Journal of Environmental Health Sciences
    • /
    • v.32 no.5 s.92
    • /
    • pp.478-484
    • /
    • 2006
  • There was no significant difference in the CADR (Clean Air Delivery Rate) between physical aerosols, NaCl and smoke, and biological aerosols, airborne MS2 virus and P. fluorescens, which implicate that the hybrid-type of air purifier, applying the unipolar ion emission and the radiant catalytic ionization, imposed identical reduction effect on both physical aerosol and bioaerosol. Ventilation decreases the efficiency of air cleaning by unipolar ionization because high ventilation diminishes the particle concentration reduction effect. The particle removal efficiency decreases with increase in the chamber volume because of the augmented ion diffusion and higher ion wall loss rate. Particle size affects the efficiency of air ionization. The efficiency is high for particles with very small diameter because reduction of charge increases with particle size. If there is no increasing supply of ions, the efficiency of air cleaning by unipolar ionization increases with respect to initial concentration of particles because of the large space charge effect at high particle concentration and amplified electric field.

Characteristics of Ocean Scanning Multi-spectral Imager(OSMI) (Ocean Scanning Multi-spectral Imager (OSMI) 특성)

  • Young Min Cho;Sang-Soon Yong;Sun Hee Woo;Sang-Gyu Lee;Kyoung-Hwan Oh;Hong-Yul Paik
    • Korean Journal of Remote Sensing
    • /
    • v.14 no.3
    • /
    • pp.223-231
    • /
    • 1998
  • Ocean Scanning Multispectral Imager (OSMI) is a payload on the Korean Multi-Purpose SATellite (KOMPSAT) to perform worldwide ocean color monitoring for the study of biological oceanography. The instrument images the ocean surface using a whisk-broom motion with a swath width of 800 km and a ground sample distance (GSD) of less than 1 km over the entire field-of-view (FOV). The instrument is designed to have an on-orbit operation duty cycle of 20% over the mission lifetime of 3 years with the functions of programmable gain/offset and on-orbit image data storage. The instrument also performs sun calibration and dark calibration for on-orbit instalment calibration. The OSMI instrument is a multi-spectral imager covering the spectral range from 400 nm to 900 nm using a Charge Coupled Device (CCD) Focal Plane Array (FPA). The ocean colors are monitored using 6 spectral channels that can be selected via ground commands after launch. The instrument performances are fully measured for 8 basic spectral bands centered at 412, 443, 490, 510, 555, 670, 765 and 865 nm during ground characterization of instalment. In addition to the ground calibration, the on-orbit calibration will also be used for the on-orbit band selection. The on-orbit band selection capability can provide great flexibility in ocean color monitoring.

Influence of the Insulating Properties on Charge Injection Phenomena of Biaxially-Drawn Polypropylene Film (이축 연신된 폴리프로필렌 필름의 전하주입 현상이 절연특성에 미치는 영향)

  • 이준웅;김병태;박승협
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.1 no.2
    • /
    • pp.74-81
    • /
    • 1987
  • The reduction in dielectric strength of insulating polymer material when applying electric field is known to be substantial due to the trapped carrier effect. In this study, the carrier property of Biaxially-Drawn polypropylene, which has superior heat-resistance compared to ordinary one, is examined to improve electrical characteristics by measuring TSC spectra as a function of electric field applied to a sample of ($50{\mu}m$) thickness film. The TSC spectra in the temperature range of 303-413(K) and electric field of 2-80(MV/m) have shown no observable effect below 12(MV 1m) but TSC currents of Hetero-and Homo-peaks formed from trapped space charger and space charger injected from electrode have been observed above that point, which seems eventually lead to dielectric breakdown. Finally, this study has shown the superior dielectric proporty of Biaxially-Drawn polypropylene film compared to the non-oriented one for electrical insulation.

  • PDF

Negative Corona Onset Characteristic of the UHV Conductors Based on the Corona Cage

  • Liu, Yun-Peng;Zhu, Lei;Lv, Fang-Cheng;Xie, Xiongjie
    • Journal of Electrical Engineering and Technology
    • /
    • v.9 no.6
    • /
    • pp.2089-2097
    • /
    • 2014
  • Negative corona onset characteristics of the stranded conductors based on the ultra-high voltage (UHV) corona cage were studied in the paper. Based on the corona self-sustaining criterion in extreme uneven electric fields and the secondary emission process of the photoelectrons, the corona onset calculation model in the UHV corona cage is established and the corona current tests of the single LGJ900-75, 6 bundle LGJ900-75, 8 bundle LGJ400-35 conductors in dry and rain conditions were done in the UHV corona cage, and the rain rates are 2.4 mm/h, 20 mm/h and 30 mm/h. Corona onset electric field strength is gained by E-I tangent method, and the onset electric field strength in dry condition proves that the calculation model can be used to calculate the corona onset characteristics of the bundle conductors in the UHV corona cage. A further analysis proves that: the negative corona onset voltage of the conductor increases with the bundle number and the diameter of the sub conductor, but decreases with the bundle space in the corona cage. The onset electric field strength is influenced little by bundle space and bundle number, but decreases with the increase of the diameter of the sub-conductor. The surface irregularity coefficient decreases with the rain rate.

Thermal Strain Measurement of Austin Stainless Steel (SS304) during a Heating-cooling Process

  • Ha, Ngoc San;Le, Vinh Tung;Goo, Nam Seo;Kim, Jae Young
    • International Journal of Aeronautical and Space Sciences
    • /
    • v.18 no.2
    • /
    • pp.206-214
    • /
    • 2017
  • In this study, measurement of thermophysical properties of materials at high temperatures was performed. This experiment employed a heater device to heat the material to a high temperature. The images of the specimen surface due to thermal load at various temperatures were recorded using charge-coupled device (CCD) cameras. Afterwards, the full-field thermal deformation of the specimen was determined using the digital image correlation (DIC) method. The capability and accuracy of the proposed technique are verified by two experiments: (1) thermal deformation and strain measurement of a stainless steel specimen that was heated to $590^{\circ}C$ and (2) thermal expansion and thermal contraction measurements of specimen in the process of heating and cooling. This research focused on two goals: first, obtaining the temperature dependence of the coefficient of thermal expansion, which can be used as data input for finite element simulation; and second, investigating the capability of the DIC method in measuring full-field thermal deformation and strain. The results of the measured coefficient of thermal expansion were close to the values available in the handbook. The measurement results were in good agreement with finite element method simulation results. The results reveal that DIC is an effective and accurate technique for measuring full-field high-temperature thermal strain in engineering fields such as aerospace engineering.

Study of the Dependence of the Electric Potential on Surface Plasmon Resonance Characteristics (금속 표면의 전위가 표면 플라즈몬 공명 특성에 미치는 영향에 대한 연구)

  • Jeong, Intae;Kwon, Jooseong;Park, Young June
    • Korean Journal of Optics and Photonics
    • /
    • v.25 no.2
    • /
    • pp.95-101
    • /
    • 2014
  • When voltage is applied on the metal layer of a surface plasmon resonance (SPR) sensor, electric field excitation causes charge accumulation on the metal surface. This alters not only the optical properties of the metal but also the SPR angle. In this study we investigate this effectby performing experiments using solutions of various pH values, and we obtain the relation between total surface charge and SPR angle. The curves for the various pH conditions become coincident. We compare our results to those from an earlier space charge layer (SCL) model, and suggest a modified SCL model which explains our result well. This result will be useful in applications of SPR sensors, and in studying the optical properties of thin metal layers.

Film Thickness Dependence of Ac High Field for Low Density Polyethylene (저밀도 폴리에틸렌의 고전계 파형에 대한 필름 두께 의존성)

  • Choi, Yong-Sung;Wee, Sung-Dong;Hwang, Jong-Sun;Lee, Kyung-Sup
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2008.04c
    • /
    • pp.45-49
    • /
    • 2008
  • Polyethylene is widely used as the insulator for power cable. To investigate the conduction mechanism for power cable insulation under ac high field, it is very important to acquire the dissipation current under actual running field. Recently, we have developed the unique system, which make possible to observe the nonlinear dissipation current waveform. In this system, to observe the nonlinear properties with high accuracy, capacitive current component is canceled by using inverse capacitive current signal instead of using the bridge circuit for canceling it. We have already reported that the dissipation currents of $40\;{\mu}m$ thick LDPE film at 10 kV/mm and over 140 Hz, it starts to show nonlinearity and odd number's harmonics were getting large. To investigate the conduction mechanis ms in this region, especially space charge effect, various kinds of estimation, such as time variations of instantaneous resistivity for one cycle, FFT spectra of dissipation current waveforms and so on, has been examined. As the results of these estimations, it was found that the dissipation current will depend on not only the instantaneous value of electric field but also the time differential of applied electric field due to taking a balance between applied field and internal field. Furthermore, two large peaks of dissipation current for each half cycle were observed under certain condition. In this paper, to clarify the reason why it shows two peaks for each half cycle, the film thickness dependences of dissipation current waveforms were observed by using the three different thickness LDPE films.

  • PDF

A Research Trend on Film Thickness Dependence of Ac High Feld for Low Density Polyethylene (저밀도 폴리에틸렌을 위한 고전계 파형의 필름 두께의존성에 관한 연구 동향)

  • Jung, Sung-Chan;Rho, Jung-Hyun;Lee, Joo-Hong;Hwang, Jong-Sun;Choi, Yong-Sung;Lee, Kyung-Sup
    • Proceedings of the KIEE Conference
    • /
    • 2007.07a
    • /
    • pp.1988-1989
    • /
    • 2007
  • Polyethylene is widely used as the insulator for power cable. To investigate the conduction mechanism for power cable insulation under ac high field, it is very important to acquire the dissipation current under actual running field. Recently, we have developed the unique system, which make possible to observe the nonlinear dissipation current waveform. In this system, to observe the nonlinear properties with high accuracy, capacitive current component is canceled by using inverse capacitive current signal instead of using the bridge circuit for canceling it. We have already reported that the dissipation currents of $40\;{\mu}m$ thick LDPE film at 10 kV/mm and over 140 Hz, it starts to show nonlinearity and odd number's harmonics were getting large. To investigate the conduction mechanis ms in this region, especially space charge effect, various kinds of estimation, such as time variations of instantaneous resistivity for one cycle, FFT spectra of dissipation current waveforms and so on, has been examined. As the results of these estimations, it was found that the dissipation current will depend on not only the instantaneous value of electric field but also the time differential of applied electric field due to taking a balance between applied field and internal field. Furthermore, two large peaks of dissipation current for each half cycle were observed under certain condition. In this paper, to clarify the reason why it shows two peaks for each half cycle, the film thickness dependences of dissipation current waveforms were observed by using the three different thickness LDPE films.

  • PDF