• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.115-118
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• 2004

In this paper, a Fiber Bragg Grating (FBG) sensor system for smart structures is described. FBGs are well-suited for long term and extremely severe experiments, where traditional strain gauges fail. In the system, a reflect wave-length measurement method which employs a tunable light source to find out the center wave-length of FBG sensor is used. We applied the FBG system to composite repairing structures and beam column joint of building structure. We also applied the system to nuclear energy power plant for structural integrity test to measure the displacement of the structure under designed pressure and to check the elasticity of the structure by measuring the residual strain. The system works very well and it is expected that it can be used for a real-time strain, temperature and vibration detectors as parts of smart structures.

• Applied Science and Convergence Technology
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• v.23 no.3
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• pp.128-133
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• 2014

We study the ballistic spin transport properties in a two-dimensional electron gas system in the presence of magnetic barriers using a transfer matrix method. We concentrate on the size-effect of the magnetic barriers parallel to a two-dimensional electron gas plane. We calculate the transmission probability of the ballistic spin transport in the magnetic barrier structure while varying the width of the magnetic barriers. It is shown that resonant tunneling oscillation is affected by the width and height of the magnetic barriers sensitively as well as by the inter-spacing of the barriers. We also consider the effect of additional electrostatic modulation on the top of the magnetic barriers, which could enhance the current spin polarization. Because all-semiconductor-based devices are free from the resistance mismatch problem, a resonant tunneling structure using the two-dimensional electron gas system with electric-magnetic modulation would play an important role in future spintronics applications. From the results here, we provide information on the physical parameters of a device to produce well-defined spin-polarized current.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.1
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• pp.54-57
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• 2005

A soft error rate neutrons is a growing problem fur terrestrial integrated circuits with technology scaling. In the acceleration test with high-density neutron beam, a latch-up prohibits accurate estimations of the soft error rate (SER). This paper presents results of analysis for the latch-up characteristics in the circumstance corresponding to the acceleration SER test for SRAM. Simulation results, using a two-dimensional device simulator, show that the deep p-well structure has better latch-up immunity compared to normal twin and triple well structures. In addition, it is more effective to minimize the distance to ground power compared with controlling a path to the $V_{DD}$ power.

• Journal of the Semiconductor & Display Technology
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• v.14 no.4
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• pp.45-49
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• 2015

Using a combined CVD and ALD equipment system, multi-layer quantum well structures of $Al_2O_3/a-Si/Al_2O_3$ were fabricated on silicon Schottky junction devices and implemented to quantum well solar cells, in which the 1~1.5 nm thicknesses of the aluminum oxide films and the a-Si thin film layers were deposited at $300^{\circ}C$ and $450^{\circ}C$, respectively. Fabricated solar cell was operated by tunneling phenomena through the inserted quantum well structure being generated electrons on the silicon surface. Efficiency of the fabricated solar cell inserted with multi-quantum well of 41 layers has been increased by about 10 times that of the solar cell of pure Schottky junction solar cell.

• Proceedings of the KSPS conference
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• 1997.07a
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• pp.92-114
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• 1997

This study is aimed to grasp the actual problems of the perception of English rhythm and intonation structure by Korean University students who have studied English in the secondary schools for the past six years, and to establish the systems of English rhythm and intonation structure for the Korean students of English. For this study, the listening test is provided, and 100 students are chosen as the subjects of the study. The noticeable findings are summarized as follows: (1) Koreans perceive the words stress comparatively well in nonsense words, unfamiliar place names, and familiar word. (2) Koreans do not perceive the isochrony of English rhythm well enough. The perception of the sentence stress is very unstable, especially in the sentence involved in polysyllabic words, compound words, and 'emphatic stress' pr 'contrastive stress'(or in the different rhythmic patterns). (3) Koreans do not perceive the nucleus well enough. The perception of the nucleus is more stable in content words than in function words, at the end of a sentence than in the middle of a sentence, and in monosyllabic words than in the polysyllabic words. (4) Koreans do not perceive the boundary(or pause) of intonation group well enough. The perception of the pause is unstable in the long or complex sentence. (5) Koreans discriminate the meaning of English word stress comparatively well, especially in disyllabic words. But the discrimination is somewhat unstable in polysyllabic words and between 'adjective' and 'verb' (6) Koreans' discrimination of the intonation meaning is below the level. Koreans do not perceive the differences of intonation meaning according to the pitch accent or the focus. In conclusion, the writer will propose the procedures for the teaching of rhythm and intonation in the following order: word stress drill longrightarrowstressed and reduced syllables drilllongrightarrowrhythm group drilllongrightarrowthe varying rhythm drilllongrightarrowsentence stress drilllongrightarrownucleus drill longrightarrowintonation group drilllongrightarrowlong utterance drill of more than two intonation group.

• Journal of Environmental Impact Assessment
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• v.9 no.4
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• pp.349-362
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• 2000

In the study, the feasibility of landscape ecological measures as indices system for interpretation and evaluation of regional ecosystem was investigated through the application to Yongin City. Each patch metrics well showed the class structure and supplemented the class metrics, and class metrics also showed well the landscape structure and supplemented the landscape metrics. And the change analysis through subtraction of two set of landscape ecological measurement in two point of time showed the dynamic trends very well. One of the dynamic trends in Yongin City was the rapid fragmentation. While there was no landcover data on Yongin City, using Landsat data and remote sensing techniques were proved to be efficient and effective to produce the digital landcover data.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.2
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• pp.131-139
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• 1996

Inthis apper wa analyzed the channel-hot-electron programming characteristics of the single-poly EEPROM with different control gate and drain structures. The single-poly EEPROM uses the p$^{+}$/n$^{+}$-diffusion in the n-well as a control gate instead of the second poly-silicon. The program and erase characteristics of the single-poly EEPROM were verified using the two-dimensional device simulator, MEDICI. The single-poly EEPROM was fabricated using 0.8$\mu$m ASIC CMOS process, and its CHE programming characteristics were measured using HP4155 parameteric analyzer and HP8110 pulse gnerator. Especially we investigated the CHE programming characteristics of the single-poly EEPROM with the p$^{+}$-diffusion or n$^{+}$-diffusion in the n-well as a control gate and the LDD or single-drain structure. The single-poly EEPROM with p$^{+}$-diffusion in the n-well as a control gate and single-drain structure was programmed to about VT$\thickapprox$5V with VDS=6V, VCG=12V(1ms pulse width).th).

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.339-341
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• 1997

From this first studies, We have investigated the latch-up characteristics of various CMOS well structures possible with high energy ion implantation processes. In this study, we also investigated those of STI(Shallow Trench Isolation} structures with varing n+/p+ spacing and the depth of trench. STI structure is formed by T-SUPREM4 process simulator, and then latch-up simulations for each case were performed by MEDICI device simulator for latch-up immunity improvement. STI is very effective to preventing the degradation of latch-up characteristics as the n+/p+ spacing is reduced. These studies will allow us to evaluate each technology and suggest guidelines for the optimization of latch-up susceptibility.

• 한국전기화학회:학술대회논문집
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• 2003.07a
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• pp.83-88
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• 2003

PtRu alloy and $PtRu-WO_3$ nanocomposite thin-film electrodes for methanol electrooxidation were fabricated by means of a sputtering method. The structural and electrochemical properties of well-defined PtRu alloy thin-film electrodes were characterized using X-ray diffraction, Rutherford backscattering spectroscopy. X-ray photoelectron spectroscopy, and electrochemical measurements. The alloy thin-film electrodes were classified as follows: Pt-based and Ru-based alloy structure. Based on structural and electrochemical understanding of the PtRu alloy thin-film electrodes, the well-controlled physical and (electro)chemical properties of $PtRu-WO_3$, showed superior specific current to that of a nanosized PtRu alloy catalyst, The homogeneous dispersion of alloy catalyst and well-formed nanophase structure would lead to an excellent catalytic electrode reaction for high-performance fuel cells. In addition, the enhanced catalytic activity in nanocomposite electrode was found to be closely related to proton transfer in tungsten oxide using in-situ electrochemical transmittance measurement.

• Journal of Integrative Natural Science
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• v.2 no.4
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• pp.265-269
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• 2009

The photoluminescence was measured in GaAs-AlGaAs double-quantum-well structure at high magnetic field. Although the phototransition characteristics displayed a free-particle transition at low magnetic field, the change of free-particle transition into bound-exciton transition was observed at high magnetic field (above 10 T). A charged exciton formation due to charge-unbalanced electron-hole was identified by using a spin-polarized photoluminescence method. An increase of exciton formation due to the localization of free-particle at magnetic field was observed according to the increase of magnetic field.