• Laser Solutions
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• v.7 no.2
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• pp.11-18
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• 2004

We propose a novel application of optical coherence tomography (OCT) to monitor pit formation in laser irradiated optical storage materials. A multilayer optical storage recordable compact disk, is composed of multiple layers, each of different structure. Disks were irradiated with aQ-Switched Nd:YAG laser with an energy of 373 mJ. Post-irradiated disks were evaluated by OCT and those images were compared with optical microscopy. Our results indicate that OCT is a useful instrument to investigate pit formation in multilayer optical storage disks and might also provide information to optimize optical memory technology.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.3
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• pp.416-423
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• 2012

Using Ansoft HFSS(High Frequency Structure Simulator) and Serenade(circuit simulator), multilayer LPF and RF diode switch for GSM were designed. Diodes were transformed the inductor and capacitor in Tx and Rx for the simulation of equivalent circuit, respectively. In particular, the design of the simulation for multilayer RF diode switch was carried out with considering the variance of device and contraction percentage.

• Journal of the Optical Society of Korea
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• v.13 no.3
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• pp.398-402
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• 2009

We present a method of using one-dimensional dielectric multilayer structures for designing terahertz frequency spreading filters. The interference of terahertz pulses in these structures composed of alternating weak and strong refractive materials allows design of well-separated THz frequency components within a modulation-limited THz spectral envelope. The design characteristics of these coarse THz combs are limited by the saturation effect and also by the deformation of the THz pulse time-traveling within the structure. The details of the designed THz waveform synthesis from these THz multilayer spectral filters are verified by experiments using time-domain terahertz pulsed spectroscopy.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.658-659
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• 2006

Magnetron sputtered TiN, (Ti, Al)N and TiN/(Ti, Al)N multilayer coatings grown on cemented carbide substrates have been characterized by using electron probe microanalysis (EPMA), X-ray diffraction (XRD), scanning electron spectroscopy (SEM), nanoindentation, scratcher and cutting tests. Results show that TiN coating is bell mouth columnar structures, (Ti, Al)N coating is straight columnar structures and the modulation structure has been formed in the TiN/(Ti, Al)N multilayer coating. TiN/(Ti, Al)N multilayer coating exhibited higher hardness, better adhesion with substrate and excellent cutting performance compared with TiN and (Ti, Al)N coating.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.385-386
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• 2007

We prepared the Al doped ZnO coating Ag multilayer thin films on glass without substrate heating using FTS system. The structure of multilayer thin films has Al doped ZnO/Ag/Al doped ZnO(AZO/Ag/AZO). The thickness of top and bottom AZO thin films were fixed to 50 nm, respectively and controlled the thickness of Ag thin films with deposition time. As-doped multilayer thin films were prepared at 1mTorr and input power (DC) of 100W at room temperature. To investigate the film properties, we employed four-point probe, UVNIS spectrometer, X-ray diffractometer (XRD), scanning electron microscopy (SEM), Hall Effect measurement system and Atomic Force Microscope (AFM).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.1
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• pp.31-34
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• 2007

In this study, in order to develop multilayer ceramics vibrator for ultrasonic nozzle, PMN-PNN-PZT ceramics were fabricated using $Li_{2}CO_{3}-Na_{2}_CO_{3}$ as sintering aids and their piezoelectric and dielectric characteristics were investigated according to the amount of PbO. With increasing PbO contents, secondary phases were increased and phase structure was changed from tetragonal structure to rhombohedral structure and also electromechanical coupling factor was linearly decreased. At the composition ceramics with the sintering temperature of $870^{\circ}C$ and 1 mol% excess PbO, density, electromechanical coupling factor, dielectric constant, piezoelectric d constant and mechanical quality factor showed the optimum value of $7.879\;g/cm^{3}$, 0.55, 1149, 328 pC/N, 1224, respectively for multilayer ceramics vibrator application for ultrasonic nozzle.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.2
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• pp.82-88
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• 1999

In this paper, we propose a new structure optimization method of multilayer neural networks which begin and carry out learning from a bigger network. This method redundant links and neurons according to the rough set theory. In order to find redundant links, we analyze the variations of all weights and output errors in every step of the learning process, and then make the decision table from their variation of weights and output errors. We can find the redundant links from the initial structure by analyzing the decision table using the rough set theory. This enables us to build a structure as compact as possible, and also enables mapping between input and output. We show the validity and effectiveness of the proposed algorithm by applying it to the XOR problem.

• Journal of the Korean Society of Radiology
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• v.12 no.1
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• pp.101-106
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• 2018

Multilayer mirrors have widely been used for monochromatization of X-ray with high reflection efficiency. The reflected X-ray energy or wavelength is determined by the d-spacing of a multilayer mirror and the incidence angle. The reflectivity critically depends on the number of bilayers and surface roughness on each interface. The multilayer mirror has a structure of alternative deposition of high and low Z-elements on the substrate. Each interface should be considered in the calculation of reflectivity. In this paper, we examine the degradation of reflectivity by the inter-diffusion combined with surface roughness on each interface for a W/Si multilayer mirror. In the depth-graded W/Si multilayer mirror, the FWHMs for angle and energy were larger than them of the uniform multilayer mirror. Inter-diffusion considerable gave rise to the degradation of reflectivity. To obtain measured reflectivity closed to the expected reflectivity, the inter-diffusion on W-Si and Si-W interfaces should be considered.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.1
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• pp.25-30
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• 2020

Oxide (SiO₂)/Metal(Ag)/Oxide(SiO₂, ITO, ZnO) multilayer films were fabricated using a magnetron sputtering technique at room temperature on Si (p-type, 100) and a glass substrate. The electrical and optical properties of the asymmetric multilayer films depended on the thickness of the mid-layer film and the type of oxide in the bottom layer. As the metal layer becomes thicker, the sheet resistance decreases. However, the transmittance decreases when the metal layer exceeds a threshold thickness of approximately 10~12 nm. In addition, the sheet resistance and transmittance change according to the type of oxide in the bottom layer. If the oxide has a large resistivity, the overall sheet resistance increases. In addition, the anti-reflection effect changes according to the refractive index of the oxide material. The optical and electrical properties of multilayer films were investigated using an ultraviolet visible (UV-Vis) spectrophotometer and a 4-point probe, respectively. The optimum structure is SiO₂ (30 nm)/Ag (10 nm)/ZnO (30 nm) multilayer, with the highest FOM value of 7.7×10^-3 Ω^-1.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.2
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• pp.19-24
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• 2001

The effect of thickness variation and inter-diffusion layer on the reflectivity of Mo/Si multilayer has been investigated. The reflectivity of the imperfect Mo/Si multilayer with thickness variation of 28% was found to be lowered by 10.8% compared to that of ideal Mo/Si multilayers with 40-periods. When the inter-diffusion layer is taken into account, the reflectivity is decreased by 4.7% additionally. We also fecund that the reflectivity continued to increase until the 25th-layer but it showed irregular tendencies about increment and decrement from the 26th-layer of Mo/Si multilayer structures.