• Journal of the Korean Chemical Society
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• v.39 no.6
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• pp.440-445
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• 1995

The chemical compositions and stability constants, thermodynamic parameters for the neodymium(Ⅲ) complexes of substituted benzo-1,4,7,10,13-pentaoxacyclopentadecane(B15C5) have been determined by spectrophotometry and conductometry in methanol solution at various temperatures. As substituents, CH3, Br, CHO, NO2, and 3,4-(NO2)2 were used. In methanol solution the ratios of neodymium(Ⅲ) to the ligands in the complexes are 1 : 1. The stability constants were increased in order of B15C5-3,4-(NO2)2 < B15C5-NO2 < B15C5-CHO < B15C5-Br < B15C5 < B15C5-CH3. This observation can be explained in terms of the substituent effect. The order of stability constants was dimethylsulfoxide < acetone < acetonitrile in solution and the magnitudes were found to be inversely proportional to the solvents donicities. These results could be understood in terms of solvent basicity, ligand basicity, solvation of the cation, and entropy changes of complex formation.

• Korean Journal of Materials Research
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• v.11 no.7
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• pp.562-568
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• 2001

Devitrifiable solder glass/$ZrB_2$ sintered composites were prepared by using glass with the composition of $60ZnO-20B_2O_3-10SiO_2-10PbO$(in wt%) and $ZrB_2$, powder as starting materials under the $N_2$atmosphere. $ZrB_2$which the good conduction materials showed sensitive oxidation characteristics, because some parts of the $ZrB_2$in specimens changed into the insulated phase of $ZrO_2$. These Phenomena would be estimated that it caused a few amount of residual oxygen in the furnace and/or specimens and the coordination number change of $B_2O_3$ in the glass. The sintering temperature and the mixed ratios of each phase were control of large ranged the resistivity ranged from 10 to 10$^{3}{\Omega}/cm^2$ orders, and to make a conductible microstructure. From these results, it would be explained that the conduction path of $ZrB_2$particles built up within sintered glass matrix.

• Journal of Magnetics
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• v.10 no.4
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• pp.152-156
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• 2005

Effects of the disproportionating hydrogen pressure and alloy composition on the texture in the HDDR-treated Nd-Fe-B particles were examined using the $Nd_{12.6}Fe_{81.4}B_6$ and $Nd_{12.6}Fe_{68.7}B_6Co_{11.0}Ga_{1.0}Zr_{0.l}$ alloys. Disproportionation kinetics of the $Nd_2Fe_{14}B$ phase in the Nd-Fe-B alloy was retarded significantly by the addition of Co, Ga and Zr. The retarded disproportionation kinetics of the $Nd_2Fe_{14}B$ phase ensured a wider processing win­dow in terms of disproportionating hydrogen pressure for achieving a texture in the HDDR-treated Nd-Fe-B alloy particles.

• The Korean Journal of Quaternary Research
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• v.16 no.2
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• pp.39-56
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• 2002

The results of geoarchaeological studies of the prehistoric cultural complexes on the Russian Far East (Primorye, or Maritime Province; the Amur River basin; and Sakhalin Island) are presented. Upper Palaeolithic sites are dated to ca. 40,000-10,500 B.P. They existed during the mild climate of the Chernoruchie interstadial (ca. 40,000-21,000 B.P.); during harsh climate at the Last Glacial Maximum, ca. 20,000-18,000 B.P., in several places on the Russian Far East (Primorye, Amur River basin, and Sakhalin); and during climatic amelioration in the Late Glacial time, ca. 16,000-10,500 B.P. The earliest Neolithic sites, represented by Osipovka and Gromatukha cultures, existed at ca. 13,000-10,000 B.P. in the environment of coniferous forests with admixture of broadleaved taxa. Since ca. 8000 B.P., Neolithic cultures appeared in all of the Russian Far East. They existed until ca. 3000 B.P., first during the Holocene Climatic Optimum, ca. 8000-5000 B.P., in the environment of coniferous-broadleaved forests, and later, at ca. 5000-3000 B.P., in the environment of birch-oak and coniferous forests.

• Korean Journal of Optics and Photonics
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• v.10 no.1
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• pp.64-67
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• 1999

We have been implemented 10 Gb/s-320 km of dispersion-shifted fiber (DSF) transmission. The optical link consists of a 10 Gb/s optical transceiver, an optical booster amplifier, 3 sets of optical in-line amplifiers, an optical preamplifier and transmission fibers. Firstly, we investigated the Q-factor characteristics in terms of optical signal to noise ratio (OSNR) of 320 km of DSF, measured receiver sensitivity is -27 dBm and power penalty is 2 dB, respectively. We concluded that optical SNR degradation and path penalty gives rise to 1 dB penalty, respectively.

• Journal of the Chungcheong Mathematical Society
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• v.29 no.2
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• pp.221-227
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• 2016

This paper will discuss the huge change of b - separated, b - connectedness, b - disconnectedness and their applications when the definition of b - separated and b - connectedness are small changed.

• Journal of the Korean Magnetics Society
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• v.7 no.5
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• pp.250-257
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• 1997

The microstructure and magnetic properties of Fe-Nb-B-N thin film alloys, which produced by rf magnetron sputtering method in $Ar+N_2$ mixed gas atmosphere, were investigated. The $Fe_{70}Nb_{14}B_{11}N_5$ films, annealed at 59$0^{\circ}C$, exhibit soft magnetic properties: $4{\pi}M_s=16.5kG$ , $H_c=0.13Oe$ and ${\mu}_{eff}$ (1~10 MHz)=5, 000. The frequency stability of the Fe-Nb-B-N films has also been found to be good up to 10 MHz. The Fe-Nb-B-N thin film alloys annealed at 59$0^{\circ}C$ consist of three phase; fine crystalline $\alpha$-Fe phase with grain size of about 5~10 nm, Nb-B rich amorphous phase and Nb-nitride precipitates with the size of less than 3 nm. Annealed Fe-Nb-B films have two phases; $\alpha$-Fe grains with the size of about 10 nm and Nb-B rich amorphous phase. The addition of N decreased $\alpha$-Fe grain size due to the precipitation of NbN. The good magnetic properties of the Fe-Nb-B-N film alloys are due to fine $\alpha$-Fe grains resulting from the precipitation of NbN.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.12
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• pp.1300-1310
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• 2003

In this paper, the performance of a multicarrier CDMA system using adaptive modulation and adaptive subchannel allocation scheme is analyzed in Rayleigh fading channel. The proposed adaptive modulator consists of modulation schemes using QPSK 16 QAM, 64 QAM and 256 QAM and constellations are pointed by Gray code. In addition, the threshold of the analysis is average E$\_$b//N$\_$o/ when the BER is 1 %. In the multicarrier system with adaptive subchannel allocation scheme, each DS waveform of user is transmitted over the K subchannels with the biggest fading among L subchannels. In case of the proposed system, total 4 subchannels are used and data are transmitted over 2 subchannels with the biggest fading, which results in the threshold of each channels is 5.2 dB, 9 dB, 13.2 dB and 8.4 dB, 12.2 dB, 16.3 dB. In the case of proposed system, the BER of 10$\^$-3/ is satisfied if average E$\_$b//N$\_$o/ is 8.1 dB. This is increased performance of 12.9 dB in comparison with conventional system. The BPS according to average channel is needed average E$\_$b//N$\_$o/ of about 15 dB in 7 bit. In the case of subchannel error, the BER of 10$\^$-3/ is 13.6 dB and is declined about 5.5 dB.

• Journal of Digital Convergence
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• v.10 no.8
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• pp.81-90
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• 2012

This study is to establish the effects on B2B(Business-to-Business) industrial product market of the Marketing Communication which used in B2C(Business-to-Customer) has influences on Trust and Trust has influences on Long-Term Orientation through survey targeting 177 wholesale and retail dealers of Air-Tool distribution. Accordance with these conclusions, The Trust that the customer felt for Supplier was a positive influence on Long-Term Orientation. Also advertising of marketing communication is useful for increasing the Trust. Thus, to increase Long-Term Orientation on B2B, supplier needs to increase Trust and to find another marketing communication factors increased Trust is needed.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.1-8
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• 2011

In this paper, a microstrip bandpass filter(BPF) with 3 dB bandwidth of more than 50 % at center frequency of 30 GHz was implemented. The implemented BPF is to be used as ASK(Amplitude Shift Keying) transmission and reception filters in IF band for THz transmitter and receiver capable of 10 Gb/s wireless data transmission. The microstrip BPF with ultra-wideband characteristics was implemented using a stepped-impedance lowpass filter(LPF) and a composite quarter-wave short stubs where the LPF is functioning as attenuating the upper stopband and quarter-wave short stubs is functioning as attenuating the lower stopband. The measured results are as follows; the insertion loss is 0.65 dB at 30 GHz, the stopband characteristics are -10 dB and -16 dB at 10 GHz and 50 GHz, respectively, and the passband flatness is ${\pm}0.5$ dB at 20~40 GHz.