• Applied Science and Convergence Technology
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• 제25권2호
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• pp.42-45
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• 2016

A two-dimensional metal hole array (2DMHA) structure is fabricated by conventional photo-lithography and electron beam evaporation. The transmittance of the 2DMHA is measured at long wave infrared (LWIR) wavelengths (${\lambda}{\sim}10$ to $24{\mu}m$). The 2DMHA sample shows transmittance of 70 and 67% at $15.4{\mu}m$ due to plasmonic resonance with perforated silver and gold thin films, respectively, under surface normal illumination at LWIR wavelengths. The measured infrared spectrum is separated into two peaks when the size of the hole becomes larger than a half-pitch of the hole array. Six degenerated plasmon modes (1,0) at the metal/Si surface split to three modes at an incident beam angle of $45^{\circ}$ with respect to the surface normal direction, and wavelength shifts of the transmitted spectrum are observed in a red shift and blue shift at the same time.

• 한국결정학회:학술대회논문집
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• 한국결정학회 2002년도 정기총회 및 추계학술연구발표회
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• pp.15-15
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• 2002

Homogeneous and crack-free potassium lithium niobate (K₃Li/sub 2-x/Nb/sub 5+x/O/sub 15/, 0＜x＜0.5, KLN) single crystals were successfully grown by the Czochralski technique. The KLN single crystals of several different compositions were employed for the investigation of the lattice vibration spectra using infrared Raman spectroscopy. The characteristic Raman spectra of the [NbO/sub 6/]/sup 7-/ octahedral ions were strikingly influenced by the Li ion content. The symmetric stretch vibrational modes V₁, V₂ are broadened, and the symmetric bend vibration mode V/sub 5/ is broadened and even split into three peaks with increasing the Li content, supporting that the bend vibration modes of the [NbO/sub 6/]/sup 7-/ octahedrons are obviously perturbed by Li ions in the C site. Enhanced Raman peak intensities after the post annealing at 900℃ and for 24 h evidenced that a residual stress in as-grown crystals was negligible and only a defect concentration might be reduced.

• Journal of Power Electronics
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• 제19권6호
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• pp.1440-1448
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• 2019

In wireless power transfer systems, it is important to design resonant energy links in order to increase the power transfer efficiency and to obtain desired system performances. This paper proposes a method for designing and analyzing the resonant energy links in a series-series configured IPT (inductive power transfer) system using the FOM-rd plane. The proposed FOM-rd graphical design plane can analyze and design the voltage gain and the power efficiency of the energy links while considering changes in the misalignment between the coils and the termination load condition. In addition, the region of the bifurcation phenomena, where voltage gain peaks are split over the frequency, can also be distinctly identified on the graphical plane. An example of the design and analysis of a 100 W inductive power transfer system with the proposed method is illustrated. The proposed method is verified by measuring the voltage gain and power efficiency of implemented hardware.

• 한국안광학회지
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• 제4권2호
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• pp.65-71
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• 1999

렌즈 염색 powder, 염색 solution, 염색 렌즈에 대한 가시 광 영역에서 광 흡수 spectrum을 측정하였다. 염색 powder는 광 흡수가 높아 염색렌즈의 색과 전혀 다르고, 짚은 회색 칼라로 구성된다. 염색 solution의 광 흡수는 전이금속의 ion들의 에너지 분리에 의한 광흡수가 미약하게 나타나 각 색조를 구성하였다. 염색 렌즈의 광 흡수는 전이금속의 ion에 의한 에너지 분리의 광 흡수 peak가 나타나 색구성에 큰 영향을 주었다. 각 렌즈의 광 흡수 peak는 염색 시간 의존성을 갖는다. 청색칼라 렌즈는 500nm 보다 단파장에서 흡수가 크고, 이상에서는 낮게 나타났다. 황색의 경우 청색과 정반대의 광 흡수가 나타나, 녹색 칼라 렌즈의 경우 가시광 양 끝단에서 광 흡수가 크고, 중간 영역에서는 흡수가 낮았다. Pink 칼라 렌즈의 경우 녹색과 정반대의 흡수 형태로 서로 보색 관계가 나타난다. Brown 칼라 렌즈의 경우 단파장에서 최대 흡수를 갖고 장파장으로 갈수록 광 흡수가 감소한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 학술대회 논문집 전문대학교육위원
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• pp.35-39
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• 2000

$ZnIn_2S_4$ and $ZnGaInS_4:Er^{3+}$ single crystals crystallized in the rhombohedral (hexagonal) space group $C_{3v}^5(R3m)$, with lattice constants $a=3.852{\AA},\;c=37.215{\AA}$ for $ZnIn_2S_4$, and $a=3.823{\AA}$, and $c=35.975{\AA}$ for $ZnIn_2S_4:Er^{3+}$. The optical absorption measured near the fundamental band edge showed that the optical energy band structure of there compounds had a direct and indirect band gap, the direct and indirect energy gaps are found to be 2.778 and 2.682 eV for $ZnIn_2S_4$, and 2.725 and 2.651eV for $ZnIn_2S_4:Er^{3+}$ at 293 K. The photoluminescence spectra of $ZnIn_2S_4:Er^{3+}$ measured in the wavelength ranges of $500nm{\sim}900nm$ at 10 K. Eight sharp emission peaks due to $Er^{3+}$ ion are observed in the regions of $549.5{\sim}550.0nm,\;661.3{\sim}676.5nm$, and $811.1{\sim}834.1nm$, and $1528.2{\sim}1556.0nm$ in $CdGaInS_4:Er^{3+}$ single crystal. These PL peaks were attributed to the radiative transitions between the split electron energy levels of the $Er^{3+}$ ions occupied at $C_{2v}$, symmetry of the $ZnIn_2S_4$ single crystals host lattice.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권1호
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• pp.12-17
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• 1999

$MgIn_2Se_4 and MgIn_2Se_4 : Ni^{2+}$ single crystals were grown in the rhombohedral structure by the chemical transport reaction (C.T.R.) method using iodine as a transport agent. The optical absorption measured near the fundamental band edge showed that the optical energy band structure of these compounds had a direct band gap. The fundamental absorption band edge of these single crystals shift to a shorter wavelength region by decreasing temperature and the temperature dependence of the optical energy gaps in these compounds satisfy Varshni equation. The impurity optical absorption peaks due to nickel are observed in $MgIn_2Se_4 and MgIn_2Se_4 : Ni^{2+}$ single crystal. These impurity optical absorption peaks can be attributed to the electronic transitions between the split energy levels of $Ni_{2+}$ ions located at $T_d$ symmetry site of $MgIn_2Se_4$ host lattice. In the hotoluminescence spectrum of the single crystal at 10 K, a blue emission with a peak at 687nm and a green emission with a peak at 815nm for the $MgIn_2Se_4$ single crystal were observed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 제4회 영호남학술대회 논문집
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• pp.97-100
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• 2002

$CdGaInS_{4}:Er^{3+}$ single crystal crystallized in the rhombohedral. with lattice constants a = 3.899 $\AA$ and c = 36.970 $\AA$ for $CdGaInS_{4}:Er^{3+}$. The optical absorption measured near the fundamental band edge showed that the optical energy band structure of this compound had a direct and indirect band gaps. the direct and indirect energy gaps are found to be 2.665 and 2.479eV for $CdGaInS_{4}:Er^{3+}$ at 10 K. The photoluminescence spectra of $CdGaInS_{4}:Er^{3+}$ measured in the wavelength ranges of 500 nm~900 nm and 1500~1600 nm at 10 K. Eight sharp emission peaks due to $Er^{3+}$ ion are observed in the regions of 549.5~560.0nm. 661.3~676.5nm. 811.1~ 834.1 nm and 1528.2~1556.0 nm in $CdGaInS_{4}:Er^{3+}$ single crystal. These PL peaks were attributed to the radiative transitions between the split electron energy levels of the $Er^{3+}$ ions occupied at $C_{2v}$ symmetry of the $CdGaInS_4$ single crystals host lattice.

• 한국광학회지
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• 제18권4호
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• pp.264-269
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• 2007

기존 필라멘트 방식의 루미나리에용 조명의 단점을 극복하기 위해 필라멘트를 LED로 바꾸기 위한 연구가 활발하게 진행 중이다. 본 연구는 루미나리에용에 적합한 LED패키지 구조를 만들기 위해 ray tracing simulator를 이용해 다양한 구조를 모델링하고 시뮬레이션을 통해 각 구조에서의 배광분포를 측정하였다. 시뮬레이션 결과, LED 패키지의 내부 반사경의 각을 증가시킬수록 배광분포가 두 개의 피크로 갈라지면서 피크간의 각이 점점 커졌다. 또한 외부 반사경 각이 증가함에 따라 양쪽 피크간의 각이 점점 줄어들다가 $50^{\circ}$를 기준으로 다시 증가하였다. 이러한 결과는 LED에서 발생한 빛이 두 개의 반사경에 의하여 반사되는 각도가 달라짐에 의하여 발생함을 알 수 있었다. Ray tracing simulator를 이용하여 구한 LED 패키지 구조의 조건을 적용하여 루미나리에용 LED패키지를 제작하였고 배광분포 측정기를 이용해 광 특성을 측정하였으며 시뮬레이션의 결과와 유사한 특성을 얻었다.

• 한국수산과학회지
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• 제48권4호
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• pp.498-506
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• 2015

We examined the feeding habits of larval Clupea pallasii using 148 specimens collected from December 2010 to April 2011 in the Nakdong River estuary, Korea. We found that larval C. pallasii [8.3-26.0 mm NL (notochord length)] are carnivorous, consuming mainly copepods, rotifers, cirripeds, and free-living flatworms (Macrostomida). Their diet also include small quantities of shrimp nauplii, tintinnids, cladocerans, and larval bivalves, among other food sources. To evaluate ontogenetic changes in dietary composition, we split larvae into four size groups: 8-12 mm, 12-16 mm, 16-20 mm, and > 20 mm NL. Rotifers were the most important prey items for the smallest group, but all other groups predominantly consumed copepods. The largest group frequently preyed on rotifers, cirripeds and flatworms, in addition to copepods. Larvae also showed bi-modal feeding, with peaks in the late afternoon and at midnight, wherein the mean number of prey per individual peaked at 1,800-1,900 h.

• 한국수산과학회지
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• 제48권5호
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• pp.752-759
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• 2015

We examined the feeding habits of larval Konosirus punctatus using 165 specimens collected from May to August 2011 in the Nakdong River estuary, Korea. We found that larval K. punctatus [3.9-8.4 mm notochord length (NL)] are carnivorous, consuming mainly rotifers. Their diet also included small numbers of rhizopods, tintinnids, euglenoids, copepods, larval bivalves, dinoflagellates, diatoms, and unidentified materials. To evaluate ontogenetic changes in dietary composition, we split the larvae into three size groups: < 5 mm, 5-6 mm, and > 6 mm NL. The smallest size group frequently preyed on rhizopods. As NL increased, the number of rotifers increased relative to those of rhizopods. Larvae also showed bimodal feeding for feeding incidence, with peaks in the midafternoon and at midnight, while the mean number of prey per individual peaked at 18:00-19:00 h.