• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.722-726
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• 2003

본 논문에서는 Porous poly-silicon cold cathode에 의해 전자를 방출하는 Ballistic electron surface-emitting display(BSD)의 전계방출 특성을 실험했다. BSD는 nanocrystalline을 둘러싼 산화막을 multi-tunneling한 전자에 의해 발광이 되는 mechanism이기 때문에 산화막의 두께를 변수로 두어 특성을 실험했다. 900℃에서 1시간에서 3시간까지 30분 간격으로산화 반응을 진행하였으며, leakage current와 emission current의 비로 효율을 나타내었을 때 1시간 30분 동안 산화 반응을 한 시료가 가장 좋은 특성을 나타내었다.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.7-13
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• 2001

Wire electrical discharge machining experiments in conducted to investigate characteristics of acoustic emission (AE) and electrical discharge energy due to current peak (I$_{p}$), pulse on time($\tau$/on/). The AE signals are obtained with a sensor attached to workpiece side. Machining states are identified with scanning electron microscopy and residual stress analyzer. It is demonstrated that the residual stress provide reliable informations about the machining states. Moreover, machining states can be detected successfully using both the residual stress and AE count rate.e.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.9
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• pp.841-847
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• 2004

EMI emission characteristics of 42" AC-PDP panel are investigated in this paper. First, EMI emission source was modeled the scan electrode and the sustain electrode to a simple electric and magnetic dipole type radiator. Second, EMI emission source was modeled as reconfigured the scan electrode and the sustain electrode. The primary source of EMI emission was investigated using FEM calculation of the wave impedance and 3 dB beam width. The third. the EMI emission level was estimated using the measured sustain electrode current. Also, EMI emission level of 42" AC-PDP was measured. The results show that the calculated EMI emission level from the simple electric dipole model was shown to agree with that from the corresponding FEM simulation.

• Current Optics and Photonics
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• v.7 no.2
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• pp.147-156
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• 2023

Circularly polarized (CP) emission can be achieved by integrating emissive materials into chiral metasurfaces. Such CP light sources in integrated device platforms are desirable for important potential applications. However, the exact characterization of the polarization state in CP emission may include some errors because of the unwanted polarization distortion caused by optical components (e.g., beam splitter) in the optical setup. Here, we consider CP emission measurements from chiral metasurfaces and characterize the polarization distortion caused by the beam splitter. We first detail the procedures for the Stokes parameters and Mueller matrix measurements. Then, we directly measure the Mueller matrix of the beam splitter and retrieve the original polarization state of CP emission from our metasurface sample. Using the measured Mueller matrix of the beam splitter, we specifically identify what contributes to polarization distortion in CP emission. Our work may provide useful guidelines for the characterization and compensation of polarization distortion in general Stokes parameter measurements.

• Korean Journal of Materials Research
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• v.18 no.7
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• pp.347-351
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• 2008

We have fabricated and evaluated newNew high high-efficiency green green-light light-emitting phosphorescent devices with an emission layer of [$TCTA/TCTA_{1/3}TAZ_{2/3}/TAZ$] : $Ir(ppy)_3$ were fabricated and evaluated, and compared the electroluminescence characteristics of these devices were compared with the conventional phosphorescent devices with emission layers of ($TCTA_{1/3}TAZ_{2/3}$) : $Ir(ppy)_3$ and (TCTA/TAZ) : $Ir(ppy)_3$. The current density, luminance, and current efficiency of the a device with an emission layer of ($80{\AA}-TCTA/90^{\circ}{\AA}-TCTA_{1/3}TAZ_{2/3}/130{\AA}-TAZ$) : 10%-$Ir(ppy)_3$ were $95\;mA/cm^2$, $25000\;cd/m^2$, and 27 cd/A at an applied voltage of 10 V, respectively. The maximum current efficiency was 52 cd/A under the a luminance value of $400\;cd/m^2$. The peak wavelength and FWHM (FWHM (full width at half maximum) in the electroluminescence spectral were 513 nm and 65 nm, respectively. The color coordinate was (0.30, 0.62) on the CIE (Commission Internationale de I'Eclairage) chart. Under the a luminance of $15000\;cd/m^2$, the current efficiency of the a device with an emission layer of ($80{\AA}-TCTA/90{\AA}-TCTA_{1/3}TAZ_{2/3}/130{\AA}-TAZ$) : 10%-$Ir(ppy)_3$ was 34 cd/A, which has beenshowed an improvement of improved 1.7 and 1.4 times compared to those of the devices with emission layers of ($300{\AA}-TCTA_{1/3}TAZ_{2/3}$) : 10%-$Ir(ppy)_3$ and ($100{\AA}-TCTA/200{\AA}$-TAZ) : 10%-$Ir(ppy)_3$, respectively.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.700-702
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• 2004

The dependence of environmental gases such as Ar, $O_2$ on the emission current from carbon nanotube emitters was examined in this study. Based on our experiments, the current density is decreased in single-wall carbon nanotubes (SWNTs), but is increased in multi-wall carbon nanotubes (MWNTs) as the vacuum level decreases from $10^{-7}$ Torr to $10^{-4}$ Torr by the inflow purging gases. The current density subsequently recovered as the vacuum level increased to $10^{-7}$ Torr when gas inflow stopped. From those results, we conclude that the MWNTs have completely different degradation characteristics in comparison to SWNTs excluding the effect of binder materials.

• 대한핵의학회:학술대회논문집
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• 1981.05a
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• pp.111-111
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• 1981

• Korean Journal of Materials Research
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• v.10 no.4
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• pp.301-304
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• 2000

A new triode type Co-silicided Si FEA(field emitter array) was realized by Co-silicidation of Co coated Si FEA and its field emission properties were investigated. The field emission properties of the fabricated device through the unit pixel with $45{\times}45$ tip array in the area of $250{\mu\textrm{m}}{\times}250{\mu\textrm{m}}$ under high vacuum condition of $10^{-8}Torr$ were as follows : the turn-on voltage was about 35V and the anode current was about $1.2\mu\textrm{A}(0.6㎁/tip)$ at the bias of $V_A=500V\;and\; V_G=55V$. The fabricated device showed the stable electrical characteristics without degradation of field emission current for the long term operation except for the initial transient state. The low turn-on voltage and the high current stability of the Co-silicided Si FEA were due to the thermal and chemical stability and the low work function of silicide layer formed at the surface of Si tip.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.594-598
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• 2010

We studied on the field emission properties of double-walled carbon nanotubes (DWCNTs) coated with lead selenide (PbSe) nanoparticles. PbSe nanoparticles were uniformly attached on the surface of the DWCNTs by a simple chemical process. The PbSe-coated DWCNTs showed highly increased emission current density and enhanced emission stability over 20 h, compared with raw DWCNTs. We consider that the enhanced field emission properties of PbSe-coated DWCNTs were attributed to the increased field enhancement factor and lowered work function of the emitters.

• Journal of Korean Society for Quality Management
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• v.17 no.1
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• pp.48-59
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• 1989

The motor vehicle emission is expected to be constrained strongly in the future in accordance with the current policy as to prevention of air pollution. This paper establishes a sequential rectifying inspection plan which satisfies the standard motor vehicle emission for the automobile producers who are currently producting the automobiles with catalytic converts. This plan also considered the constraint of the effective motor vehicle emission by way of rectifying the certification test in the past. In order to evaluate the performance of the inspection plan, the recent certification test data have also been applied. The result of the application has proved that the rectified sequential inspection plan presented in this paper satisfies the standard motor vehicle emission and can be the optimal economic inspection plan. As a result the inspection plan given in this paper will be contributed to constrain the motor vehicle emission most effectively.