• Korean Journal of Optics and Photonics
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• v.12 no.1
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• pp.40-47
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• 2001

The structural dependence of the performance of an 1.55 $1.55{\mu}m$ InGaAsPIInGaAsP MQW electro-absorption modulator for highspeed digital fiber communication was systematically investigated. The effects of n-doped SCH region length $t_n$ as well as the general structure parameters including quantum well number $N_w$, well-thickness $t_w$, detuning wavelength $\Delta\lambda$, and device length L were thoroughly analyzed. Thereby, a high-pelfoIDlance electro-absorption modulator with device length L of $100{\mu}m$ was successfully designed. The designed structure showed excellent characteristics that have residual loss less than -1.5 dB, operational voltage from 0 V to -2V, and extinction ratios of -2.92 dB at $V_{\alpha}$=-1 V and -10 dB at $V_{\alpha}$=-2V.X>=-2V.

• Journal of the Korean Mathematical Society
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• v.59 no.4
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• pp.757-774
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• 2022

Let a and b be positive even integers. An even [a, b]-factor of a graph G is a spanning subgraph H such that for every vertex v ∈ V (G), d_H(v) is even and a ≤ dH(v) ≤ b. Let κ(G) be the minimum size of a vertex set S such that G - S is disconnected or one vertex, and let σ₂(G) = min_uv∉E(G) (d(u)+d(v)). In 2005, Matsuda proved an Ore-type condition for an n-vertex graph satisfying certain properties to guarantee the existence of an even [2, b]-factor. In this paper, we prove that for an even positive integer b with b ≥ 6, if G is an n-vertex graph such that n ≥ b + 5, κ(G) ≥ 4, and σ₂(G) ≥ ${\frac{8n}{b+4}}$, then G contains an even [4, b]-factor; each condition on n, κ(G), and σ₂(G) is sharp.

• Journal of the Korean Magnetics Society
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• v.4 no.2
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• pp.122-125
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• 1994

The magnetic properties of Nd-Fe-B alloys of containing 4 at.% Nd have been studied for the development of new type rare-earth magnets. The amorphous phase of a melt-spun $Nd_{4}Fe_{85.5}B_{10.5}$ alloy is transformed into the phases which have a small amount of $Nd_{2}Fe_{14}B_{1}$ in ${\alpha}-Fe$ matrix by annealing above their crystallization temperature. The addition of Mo, Nb, V or Cu to $Nd_{4}Fe_{85.5}B_{10.5}$ alloy results in the reduction of grain size and the sub¬sequent improvement of the coercivity. The coercivity of $Nd_{4}Fe_{82}B_{10}M_{3}Cu_{1}$(M = Mo, Nb, V) alloys increases in the order of M = V < Nb < Mo and shows the highest value of 2.7 kOe when M = Mo. On the other hand, the rem¬anence of these alloys shows the opposite trend and the rn>st improved value of 1.35 T is observed when M = V.

• Transactions on Electrical and Electronic Materials
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• v.11 no.3
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• pp.120-125
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• 2010

For the fabrication of PMOS and integrated semiconductor devices, B, $BF_2$ and dual elements with B and $BF_2$ can be implanted in silicon. 15 keV B ions were implanted in silicon at $7^{\circ}$ wafer tilt and a dose of $3.0{\times}10^{16}\;cm^{-2}$. 67 keV $BF_2$ ions were implanted in silicon at $7^{\circ}$ wafer tilt and a dose of $3.0{\times}10^{15}\;cm^{-2}$. For dual implantations, 67 keV $BF_2$ and 15keV B were carried out with two implantations with dose of $1.5{\times}10^{15}\;cm^{-2}$ instead of $3.0{\times}10^{15}\;cm^{-2}$, respectively. For the electrical activation, the implanted samples were annealed with rapid thermal annealing at $1,050^{\circ}C$ for 30 seconds. The implanted profiles were characterized by using secondary ion mass spectrometry in order to measure profiles. The implanted and annealed results show that concentration profiles for the ${BF_2}^+$ implant are shallower than those for a single $B^+$ and dual ($B^+$ and ${BF_2}^+$) implants in silicon. This effect was caused by the presence of fluorine which traps interstitial silicon and ${BF_2}^+$ implants have lower diffusion effect than a single and dual implantation cases. For the fabricated diodes, current-voltage (I-V) and capacitance-voltage (C-V) were also measured with HP curve tracer and C-V plotter. Electrical measurements showed that the dual implant had the best result in comparison with the other two cases for the turn on voltage characteristics.

• Korean Chemical Engineering Research
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• v.52 no.2
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• pp.182-186
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• 2014

Two commercial carbon plates were evaluated as a current collector (bipolar plate) in the all vanadium redox-flow battery (V-RFB). The performance properties of V-RFB were test in the current density of $60mA/cm^2$. The electromotive forces (OCV at SOC 100%) of V-RFB using A and B current collector were 1.47 V and 1.54 V. The cell resistance of V-RFB using A current collector was $4.44{\sim}5.00{\Omega}{\cdot}cm^2$ and $3.28{\sim}3.75{\Omega}{\cdot}cm^2$ for charge and discharge, respectively. The cell resistance of V-RFB using B current collector was $4.19{\sim}4.42{\Omega}{\cdot}cm^2$ and $4.71{\sim}5.49{\Omega}{\cdot}cm^2$ for charge and discharge, respectively. The performance of V-RFB using each current collector was evaluated. The performance of V-RFB using A current collector was 93.1%, 76.8% and 71.4% for average current efficiency, average voltage efficiency and average energy efficiency, respectively. The performance of V-RFB using B current collector was 96.4%, 73.6% and 71.0% for average current efficiency, average voltage efficiency and average energy efficiency, respectively.

• Biomedical Science Letters
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• v.24 no.4
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• pp.390-397
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• 2018

For the specific detection of human Parvovirus B19 (HuPaV-B19), we designed ten specific PCR primers from 3,800~4,500 nucleotides of HuPaV-B19 complete genome (NC_000883.2). Seventeen candidate PCR primer sets for specific detecting HuPaV-B19 were constructed. In specific reaction of HuPaV-B19, seventeen PCR primer sets showed specific band, however five PCR primer sets were selected basis of band intensity, amplicon size and location. In non-specific reaction with seven reference viruses, four PCR primer sets showed non-specific band, however one PCR primer set is not. Detection sensitivity of final selective PCR primer set was $100fg/{\mu}L$ for 112 minute, and PCR amplicon is 539 base pairs (bp). In addition, nested PCR primer set was developed, for detection HuPaV-B19 from a low concentration of contaminated samples. Selection of nested PCR primer set was basis of sensitivity and groundwater sample tests. Detection sensitivity of final selective PCR and nested PCR primer sets for the detection of HuPaV-B19 were $100fg/{\mu}L$ and $100ag/{\mu}L$ basis of HuPaV-B19 plasmid, it was able to rapid and highly sensitive detection of HuPaV-B19 than previous reports. We expect developed PCR primer set in this study will used for detection of HuPaV-B19 in various samples.

• Clinical and Experimental Vaccine Research
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• v.12 no.2
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• pp.116-120
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• 2023

Purpose: In Japan, the data on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody titers after the booster dose of the coronavirus disease 2019 (COVID-19) vaccine are insufficient. The aim of this study is to evaluate changes in SARS-CoV-2 antibody titers before, 1, 3, and 6 months after the booster dose of the BNT162b2 COVID-19 vaccine among health care workers. Materials and Methods: A total of 268 participants who received the booster dose of the BNT162b2 vaccine were analyzed. SARS-CoV-2 antibody titers were measured before (baseline) and at 1, 3, and 6 months after the booster dose. Factors associated with changes in SARS-CoV-2 antibody titers at 1, 3, and 6 months were analyzed. Cutoff values at baseline were calculated to prevent infection of the omicron variant of COVID-19. Results: The SARS-CoV-2 antibody titers at baseline, and 1, 3, and 6 months were 1,018.3 AU/mL, 21,396.5 AU/mL, 13,704.6 AU/mL, and 8,155.6 AU/mL, respectively. Factors associated with changes in SARS-CoV-2 antibody titers at 1 month were age and SARS-CoV-2 antibody titers at baseline, whereas changes in SARS-CoV-2 antibody titers at 3 and 6 months were associated with the SARS-CoV-2 antibody titers at 1 month. The cutoff values of the SARS-CoV-2 antibody titers at baseline were 515.4 AU/mL and 13,602.7 AU/mL at baseline and 1 month after the booster dose, respectively. Conclusion: This study showed that SARS-CoV-2 antibody titers increase rapidly at 1 month after the booster dose of the BNT162b2 vaccine and begin to decrease from 1 to 6 months. Hence, another booster may be needed as soon as possible to prevent infection.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.4 s.119
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• pp.416-422
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• 2007

In this paper, a broadband 2-way power divider which can be used from 20 MHz to 500 MHz in the V/UHF band is designed using transmission-line transformer and ferrite toroid. A 2:1 impedance transformer instead of the conventional 4:1 impedance transformer is realized and this 2:1 transformer is connected with the conventional bridge-type 2-way divider to form a 2-way power divider. Insertion loss of about 3.5 dB, isolation of less than -10 dB, and return loss of less than -10 dB in most band of interest are measured.

• 전자공학회논문지 IE
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• v.45 no.2
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• pp.1-5
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• 2008

In this work, RF performance degradation due to hot carrier effects in SOI MOSFET have been measured and analyzed. The LNA that designed at $V_{GS}=0.8V$, f=2.5GHz, gain is 16.51dB and noise figure is 1.195dB. After stress at SOI, the LNA's gain and noise figure change of 15.3dB and 1.44dB with before stress.

• The Journal of the Korea Contents Association
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• v.5 no.5
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• pp.133-139
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• 2005

The neutron capture cross section of $^{99}Tc$ has been measured relative to the $^{10}B(n,\gamma)$ standard cross section by the neutron time-of-flight(TOF) method in the energy range of 0.007 eV to 47 keV using a 46-MeV electron linear accelerator(linac) at the Research Reactor. Institute, Kyoto University(KURRI). In order to experimentally prove the result obtained, the supplementary cross section measurement has been made from 0.3 eV to 1 keV using the Kyoto University Lead stowing-down spectrometer (KULS) coupling to the linac. The relative measurement by the TOF method has been normalized to the reference value(20.01 b) at 0.0253 eV and the KULS measurement to that by the TOF method. The existing experimental data and the evaluated capture cross sections in ENDF/B-VI, JENDL-3.2, and JEF-2.2 have been compared with the current measurements by the linac TOF and the KULS experiments.