• Nuclear Engineering and Technology
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• v.18 no.2
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• pp.92-96
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• 1986

The $^{93}Nb(n,n\alpha)^{89m}Y$, $^{93}Nb(n,{\alpha})^{90m}Y$ and $^{93}Nb(n,2n)^{92m}Nb$ cross sections at a neutron energy of 14.6 MeV have been measured relative to the $^{27}Al(n,p)^{27}Mg$ and $^{27}Al(n,{\alpha})^{24}Na$ cross sections. A small accelerator utilizing $T(D,n)^4He$ reaction was used as a neutron source and the neutron energy spread is about 0.4MeV at the sample. All induced activities were measured with a 70cc HPGe detector in the same geometry.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.4
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• pp.53-63
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• 2009

This work proposes a 10b 100MS/s 27.2mW $0.8mm^2$ 0.18um CMOS ADC for WLAN such as an IEEE 802.11n standard. The proposed ADC employs a three-stage pipeline architecture and minimizes power consumption and chip area by sharing as many circuits as possible. Two multiplying DACs share a single amplifier without MOS switches connected in series while the shared amplifier does not show a conventional memory effect. All three flash ADCs use only one resistor ladder while the second and third flash ADCs share all pre-amps to further reduce power consumption and chip area. The interpolation circuit employed in the flash ADCs halves the required number of pre-amps and an input-output isolated dynamic latch reduces the increased kickback noise caused by the pre-amp sharing. The prototype ADC implemented in a 0.18um n-well 1P6M CMOS process shows the DNL and INL within 0.83LSB and 1.52LSB at 10b, respectively. The ADC measures an SNDR of 52.1dB and an SFDR of 67.6dB at a sampling rate of 100MS/s. The ADC with an active die area of $0.8mm^2$ consumes 27.2mW at 1.8V and 100MS/s.

• Nonlinear Functional Analysis and Applications
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• v.27 no.4
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• pp.709-730
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• 2022

We consider the nonlinear matrix equation (NMEs) of the form 𝓤 = 𝓠 + Σ^k_i=1 𝓐^*_iℏ(𝓤)𝓐_i, where 𝓠 is n × n Hermitian positive definite matrices (HPDS), 𝓐₁, 𝓐₂, . . . , 𝓐_m are n × n matrices, and ~ is a nonlinear self-mappings of the set of all Hermitian matrices which are continuous in the trace norm. We discuss a sufficient condition ensuring the existence of a unique positive definite solution of a given NME and demonstrate this sufficient condition for a NME 𝓤 = 𝓠 + 𝓐^*₁(𝓤²/900)𝓐₁ + 𝓐^*₂(𝓤²/900)𝓐₂ + 𝓐^*₃(𝓤²/900)𝓐₃. In order to do this, we define 𝓕𝓖_w-contractive conditions and derive fixed points results based on aforesaid contractive condition for a mapping in extended Branciari b-metric distance followed by two suitable examples. In addition, we introduce weak well-posed property, weak limit shadowing property and generalized Ulam-Hyers stability in the underlying space and related results.

• The Korean Journal of Soil Zoology
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• v.4 no.2
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• pp.89-100
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• 1999

Four new and a known spacies of the order Mononchida were described and illustrated. Iotonchus obtusus sp. n. was 2.8 mm long, a=33, b=4.2, c=61, V=68%, buccal cavity=61${\times}$45 mm, and is characterized by having basally situated dorsal tooth, presence of vulval papillae and in having short, hemispherical tail with thick cuticle at terminus. Miconchus vulvapapillatum sp. . was 2.7-3.6 mm long, a=29-36, b=4.1-4.5, c=18.4-21, V=65-69%, buccal cavity=53-61${\times}$29-33 mm, spicules=132-137 mm, ventromedian supplements 28-31, and was characterized by having 5-8 pre- and post vulval papillae in contiguous series, and three pairs of vulval glands. Clarkus koreanus sp. n. was 1.1-1.3 mm long, a=27.5-28.8, b=3.5-3.9, c=12-14.5, V=60-64%, buccal cavity=24-28${\times}$13.5-15 mm, and was characterized by well offset lip region, amphids situated well below to dorsal tooth apex, and vulva elevated, with vulval flap. Coomansus ulsani sp. n. was 1.2-1.5 mm long, a=23.5-26, b=3.4-3.8, c=13.6-14.8, V=65-68%, buccal cavity=36-39${\times}$21-23 mm and was characterized by well offset lip region and a thin longitudinal ridge on vertical walls of stoma.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.2
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• pp.108-114
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• 2016

This paper presents a 2.6 GHz Doherty power amplifier IC to enhance the back-off efficiency. In order to apply to small-cell base stations, the Doherty power amplifier was fabricated using GaN-HEMT process for high power density. In addition, the implemented Doherty power amplifier was mounted on a QFN package. The implemented GaN-HEMT Doherty power amplifier was measured using LTE downlink signal with 10 MHz bandwidth and 6.5 dB PAPR for verification. A power gain of 15.8 dB, a drain efficiency of 43.0 %, and an ACLR of -30.0 dBc were obtained at an average output power level of 33.9 dBm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.11
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• pp.1019-1022
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• 2016

In this paper, a 2~16 GHz GaN wideband power amplifier MMIC s designed and fabricated using the nonuniform power amplifier design technique that utilizes drain shunt capacitors to simultaneously provide each transistor with the optimum load impedance and phase balance between input and output transmission lines. The power amplifier MMIC chip that is fabricated using the $0.25{\mu}m$ GaN HEMT foundry process of Win Semiconductors occupies an area of $3.9mm{\times}3.1mm$ and shows a linear gain of larger than 12 dB and an input return loss of greater than 10 dB. Under a continuous-wave mode, it has a saturated output power of 36.2~38.5 dBm and a power-added efficiency of about 8~16 % in 2 to 16 GHz.

• Korean Journal of Crystallography
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• v.2 no.2
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• pp.22-27
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• 1991

4-Amino-n-(2,6-dimethyk4-pyrimidnyl) benzenesulfonamide, C12H14N402. Unit cell parameters are a =12.626, b=11.262, c=9.375, a:b:r=90°, V =1333.07h3, D,at=1.390 g /cm3, and λ(Cu-Ka)=1.5418, The space group is Pca21, Orthorhombic. The final R factor of 1068 unique observed reflections is R=0.040. Two pair of molecules which related by symmetry operation has strong hydrogen bond. One is between H(N2) and N(3), and the other is H(NIA) and 0(1).

• Polymer(Korea)
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• v.27 no.1
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• pp.17-25
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• 2003

Using atom transfer radical polymerization (ATRP), polystyrene macroinitiators and polystyrene-b-poly(t-butyl acrylate) (PS-b-P(tBA) block copolymers were synthesized by CuBr/PMDETA catalyst system in solution. After hydrolysis, polystyrene-b-poly(acrylic acid), amphiphilic block copolymers, were formed. Subsequent neutralization of polyacid block led to the block ionomers. The molecular weight of the synthesized PS-b-P(tBA) block copolymers was easily-controlled to 5000-10000 and their distributions were less than 1.2. The chemical structures of the synthesized block copolymers were characterized by $^1$H-NMR and FT-IR. In the DSC thermograms, $T_g$ appeared in the vicinity of 100 $^{\circ}C$ because of higher styrene content. In addition, the phase separation of the block ionomers was observed by TEM.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.2
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• pp.123-129
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• 2017

Objectives: The purpose of this study is to enhance the application of analytical method of polar solvents(alcohols) by GCOTC (gas chromatography open tubular column) through the system suitability test(SST) to estimate the whole chromatographic system performance(integral part). Methods: To perform the SST, carried out repeatability(n=6) as analytical method of polar solvents by GCOTC, got the retention time($t_R$), standard deviation(${\sigma}_{n-1}$) of $t_R$, baseline width($w_b=4{\sigma}_{n-1}$) and calculated dead time($t_m$) by $v_m=d^2{\pi}L(f/4)$ and $v_m=t_m$ x flow rate. Results: In this experiment, obtained the basic data, there were $t_m=2$ min, methanol($t_R=3.569$, ${\sigma}_{n-1}=0.01$, $w_b=0.04$), ethanol ($t_R=3.892$, ${\sigma}_{n-1}=0.004$, $w_b=0.016$), isopropanol($t_R=4.209$, ${\sigma}_{n-1}=0.004$, $w_b=0.016$). By using these data, calculated the corrected retention time($t_R{^{\prime}}$), capacity factor(k), separation factor(${\alpha}$), number of theoretical plate(n) and resolution($R_s$) for SST and got the good results. Conclusions: Through the SST, could reconfirm the whole chromatographic performance system(integral part) for analytical method of polar solvents by GCOTC. Therefore, this analytical method expect to be widely applied at the related areas.

• Journal of Sensor Science and Technology
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• v.16 no.3
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• pp.240-245
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• 2007

AlN thin film for SAW filter application was deposited on (100) silicon, sapphire, $Si_{3}N_{4}$/Si, and $Al_{2}O_{3}$/Si substrates by reactive magnetron sputtering method, respectively. The structural characteristics were dependent on the structure of substrates. Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) and Atomic Force Microscope (AFM) have been used to analyze structural properties and preferred orientation of AlN thin films. Preferred orientation and SAW characteristic of AlN were improved by insertion of $Al_{2}O_{3}$ buffer layer. Insertion loss of SAW devices using AlN/Si and AlN/$Al_{2}O_{3}$/Si were about 33.27 dB and 30.20 dB, respectively.