• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.3
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• pp.229-235
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• 2001

Uncooled pyroelectric thin-film (Ba,Sr)TiO$_3$ infrared detectors thermally isolated from Si-substrate by Si$_3$N$_4$/SiO$_2$/Si$_3$N$_4$-membrane have been fabricated, and figures of merit for detectors were examined. The detector at $25^{\circ}C$ in air showed relatively high voltage responsivity of about 168.8 V/W and low specific detectivity of about 2.6$\times$10$^4$cm.Hz$^{1}$2//W at 1 Hz-chopping frequency because of very small signal-to-noise voltage ratio. It could be found that both thermal noise voltage and thermal time constant of the detector were very large by analyzing dependences of output waveforms on chopping frequency and temperature.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.3967-3983
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• 2014

The performance of an partial relay selection on the decode-and-forward (DF) mode cognitive radio (CR) relay networks is studied, with some important factors, including the outage probability, the bit error ratio (BER), and the average channel capacity being analyzed. Different from the conventional relay selection schemes, the impact of spectrum sensing process as well as the spectrum utilization efficiency of primary users on the performance of DF-based CR relaying networks has been taken into consideration. In particular, the exact closed-form expressions for the figures of merit such as outage probability, BER, and average channel capacity over independent and identically distributed (i.i.d.) Rayleigh fading channels, have been derived in this paper. The validity of the proposed analysis is proven by simulation, which showed that the numerical results are consistent with the theoretical analysis in terms of the outage probability, the BER and the average channel capacity. It is also shown that the full spatial diversity order can always be obtained at the signal-to-noise ratio (SNR) range of [0dB, 15dB] in the presence of multiple potential relays.

• Journal of East-West Nursing Research
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• v.17 no.1
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• pp.31-39
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• 2011

Purpose: The purpose of this study was to grasp the subjectivity of the nursing students toward CAM and put the outcomes into use as basic facts and figures in developing and applying a curriculum associated with CAM. Methods: Q methodology was employed to explore the nursing students' subjectivity from their rank-order statements. For the Q population, individual in-depth interviews and literature research were conducted. Finally, 30 participants completed 40 Q statements. The data were analyzed using the QUANL software package. Results: The current survey that probed into the subjectivity of the nursing students relative to CAM abstracted four categories, namely, practical and convinced type, keep-under-control/wait-and-see type, merit acknowledging type and limitedly accepting type. Conclusion: It is recommended that various educational programs should be developed to shift the awareness of CAM on the part of the nursing students, based on the findings set forth in the current study.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.2
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• pp.301-306
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• 2015

An ultra-compact and wideband low noise amplifier (LNA) in a quad flat non-leaded (QFN) package is presented. The LNA monolithic microwave integrated circuit (MMIC) is implemented in a $0.25{\mu}m$ GaN IC technology on a Silicon Carbide (SiC) substrate provided by Triquint. A source degeneration inductor and a gate inductor are used to obtain the noise and input matching simultaneously. The resistive feedback and inductor peaking techniques are employed to achieve a wideband characteristic. The LNA chip is mounted in the $3{\times}3-mm^2$ QFN package and measured. The supply voltages for the first and second stages are 14 V and 7 V, respectively, and the total current is 70 mA. The highest gain is 13.5 dB around the mid-band, and -3 dB frequencies are observed at 0.7 and 12 GHz. Input and output return losses ($S_{11}$ and $S_{22}$) of less than -10 dB measure from 1 to 12 GHz; there is an absolute bandwidth of 11 GHz and a fractional bandwidth of 169%. Across the bandwidth, the noise figures (NFs) are between 3 and 5 dB, while the output-referred third-order intercept points (OIP3s) are between 26 and 28 dBm. The overall chip size with all bonding pads is $1.1{\times}0.9mm^2$. To the best of our knowledge, this LNA shows the best figure-of-merit (FoM) compared with other published GaN LNAs with the same gate length.

• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.717-726
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• 2009

Multivariate models were developed for the simultaneous spectrophotometric determination of copper (II), nickel (II) and zinc (II) in water with 1-(2-thiazolylazo)-2-naphthol as chromogenic reagent in the presence of Triton X-100. To overcome the drawback of spectral interferences, principal component regression (PCR) and partial least square (PLS) multivariate calibration approaches were applied. Performances were validated with several test sets, and their results were then compared. In general, no significant difference in analytical performance between PLS and PCR models. The root mean square error of prediction (RMSEP) using three components for $Cu^{2+}$, $Ni^{2+}$ and $Zn^{2+}$ were 0.018, 0.010, 0.011 ppm, respectively. Figures of merit such as sensitivity, analytical sensitivity, limit of detection (LOD) were also estimated. High reliability was achieved when the proposed procedure was applied to simultaneous determination of $Cu^{2+}$, $Ni^{2+}$ and $Zn^{2+}$ in synthetic mixture and tap water.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.2
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• pp.5-12
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• 2000

Uncooled metallic thin-film thermopile infrared detectors have been fabricated, and the figures of merit for the detectors were examined. The hot junctions of a thermopile were prepared on a $Si_{3}N_{4}/SiO_{2}/Si_{3}N_{4}$-membrane which acts as a thermal isolation layer, the cold junctions on the membrane supported with the silicon rim which functions as a heat sink, and Au-black was used as an infrared absorber. Infrared absorbance of Au-black, which strongly depends on the chamber pressure during Au-evaporation and its mass per area, was found to be about 90 ％ in the wavelength range from 3${\mu}{\textrm}{m}$ to 14${\mu}{\textrm}{m}$. Voltage responsivity, noise equivalent power, and specific detectivity of Bi-Sb thermopile infrared detector at 5 Hz-chopping frequency were about 10.5V/W, 2.3 nW/Hz$^{1/2}$, 및 $1.9\times10^{7}$ cm.Hz$^{1/2}$/w at room temperature in air, respectively.

• Journal of the Korean Ceramic Society
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• v.38 no.11
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• pp.980-986
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• 2001

Bragg reflector type FBAR was fabricated on the Si(100) substrate. We measured a frequency response of the resonator at 5.2 GHz and analyzed it by numerical calculation considering actual acoustic losses of each layer in the structure. We fabricated nine layer Bragg reflector of W-SiO$_2$pairs using r.f. sputtering method and fabricated AlN piezoelectric and Al electrodes using pulsed dc sputtering. The return loss(S$_{11}$) of the fabricated Bragg reflector type FBAR was 12 dB at 5.38 GHz and the series resonance frequency(f$_{s}$) was 5.376 GHz and the parallel resonance frequency(f$_{p}$) was 5.3865 GHz. Effective electro-mechanical coupling constant (K$_{eff{^2}}$) and Quality factors(Q$_{s}$), the Figures of Merit of the resonator, were about 0.48% and 411, respectively. We extracted acoustic parameters of AlN piezoelectric and reflection coefficient of the Bragg reflector by numerical calculation. We could know that material acoustic impedance and wave velocity of AlN piezoelectric decreased for intrinsic value and the electromechanical coupling constant(K$_2$) value was very low owing to the poor quality of the AlN piezoelectric. Reflection coefficient of Bragg reflector was 0.99966 and reflection band was very wide from 2.5 to 9.5 GHz.

• Korean Journal of Heritage: History & Science
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• v.48 no.1
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• pp.62-79
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• 2015

The Stele for State Preceptor Doseon and Seon Master Sumi of Dogapsa Temple in Yeongam was erected in the fourth month of 1653. It was made with stone obtained from Yeosan(present-day Yeosan-myeon, Iksansi), and contains an inscription - engraved in the spring of 1651 - commemorating the two priests. The project to erect the monument was led by eminent monks, including Gakseong and Sucho, with the support of royal patrons and powerful statesmen including Prince Inpyeong(1622~1658). This monument is thought to be the first of its kind to have a capstone in the shape of a 'dragon loop' handle of the kind traditionally attached to the top of a temple bell. Stone stelae with a dragon-loop-shaped capstone continued to be used by the royalty and nobility of Joseon until the 18th century. The inscription engraved on the rear face of the monument reveals that it was made by Jo Mal-ryong, a renowned stonemason who worked on stone monuments and figures for royal tombs in the mid-Joseon period. He is known as the only stonemason to have been awarded the third highest rank(Jeong-sampum) of government, including the posts of Grand Master(Tongjeong Daebu) and General(Jeolchung Janggun), as recorded in the inscription. The monument corroborates the prevalent view that he was the creator of monumental capstones of the highest aesthetic merit in Joseon, and provides valuable insights about the leading artisans who produced monumental stones for royal tombs in the 17th century. This particular monument is highly regarded as a valuable historical relic because of the detailed information contained in the inscription, including the dates, work processes, patrons and artisans related with its creation, and because it features outstanding workmanship by some of the greatest artisans of the period. The monument also provides important clues about the transition from the Buddhist monuments created under the auspices of the royalty and nobility of mid-period Joseon to the symbolic stone structures and figures made for the tombs of royalty and nobility.