• Bulletin of the Korean Chemical Society
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• v.23 no.3
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• pp.511-514
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• 2002

• YAKHAK HOEJI
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• v.52 no.6
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• pp.488-493
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• 2008

2-Aminothiazole ring as a bioisoster of catechol in dopamine has provided with good oral availability and lipophilic property. 2-Aminoindan, is a rigid form of dopamine, was evaluated as a dopamine D3 agonist with low neurotoxicity. Dopamine D3 agonist was evaluated as selective for the treatment of Parkinson's disease. In order to develop a novel dopamine D3 agonist, we tried to synthesize the aminothiazoloindenoxazine derivative that is a hybrid structure of aminoindenoxazine and thiazole ring. cis-2-Amino-1-indanol (2) was synthesized from 1,2-indandione-2-oxime by catalytic hydrogenation and it was treated with chloroacetyl chloride and NaH in benzene solution to give (${\pm}$)-cis-4,4a,5,9b-tetrahydroindeno[1,2-b][1,4]oxazin-3(2H)-one (6). Nitration of 6 by the mixed acid gave 8-nitro compound (7) and the carbonyl group of 7 was reduced with $LiAlH_4$ to afford compound (8). 8 was reduced to form (${\pm}$)-cis-8-amino-2,3,4,4a,5,9b-hexahydroindeno[1,2-b][1,4]oxazine (9) and finally it was cyclized with KSCN in glacial acetic acid to yield (${\pm}$)-cis-8-amino-2,3,4,4a,5,10b-hexahydrothiazolo[4,5-f]indeno[1,2-b][1,4]oxazine (10).

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.3
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• pp.1-9
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• 2003

In this paper, we designed a highly suppressed sidelobe ladder type RF SAW bandpass filter based on 1-port resonator, for 800 MHz mobile communication system. In order to get the highest device characteristics, we optimized some important parameters such as the electrode thickness, electrode lambda weghting of the reflectors, and static capacitance ratio. Furthermore, we fabricated the Tx and Rx. filter using optimized parameters. Implemented filters can be used in 800 MHz mobile communication system and external impedance matching circuits are not needed. RF filter was fabricated on 36$^{\circ}$LiTaO$_3$ substrates with Al-Cu (W 3 %)and mounted 3.8mm$\times$3.8mm$\times$1.5mm SMD package. Developed filters has 2.3 dB insertion loss in the 25 MHz pass-band, 33MHz with 3-dB insertion loss, stop-band rejection of 30 dB, passband ripple is less than 0.5 The power durability of the filters measured about 3.5W and the maximum temperature variation within -2$0^{\circ}C$~8$0^{\circ}C$ was 0.09 dB/$^{\circ}C$ of 3-dB insertion loss.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.1
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• pp.22-26
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• 2008

Red long persistent phosphors of $CaZrO_3$ : Pr was synthesized by a solid reaction method. $CaCO_3\;and\;ZrO_2$ were used as hosting materials and Pr was doped as luminescence center element, and $B_2O_3$ was used as flux. The XRD pattern confirmed crystalline phase of the phosphor, and photoluminescence investigation showed emission spectrum at $480{\sim}570nm\;and\;590{\sim}700nm$. Phosphor samples were synthesized with $B_2O_3$ flux concentration of 1, 5, 10%, and luminescent peak of maximum intensity at 494 nm was obtained for 1% $B_2O_3$. Luminescent peak of red color at 620 nm was of highest intensity for 10% $B_2O_3$.

• Journal of the Korean Ceramic Society
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• v.41 no.9
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• pp.709-714
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• 2004

The additive of low temperature sintering in Mn-doped PMN-PZT known as high piezoelectric materials was studied in this experiment. B$_2$O$_3$ was used for the additive of low temperature sintering. The effects of sintering temperature in dielectric, and piezoelectric properties were investigated with the amounts of B$_2$O$_3$. Sintered density was increased in comparison with no addition and under 2wt％ B$_2$O$_3$ and lower sintering temperature than 100$0^{\circ}C$. Therefore, in the low sintering temperature, the densification was improved by the addition of the B$_2$O$_3$. However, the sintering density was lower than that of the main composition in the case of the sintered at over 10$50^{\circ}C$. Dielectric constant with the addition of B$_2$O$_3$ was evaluated. The dielectric constant was 1000 2 wt％ of B$_2$O$_3$ and sintered at 100$0^{\circ}C$. Under 2wt％ of B$_2$O$_3$, the electromechanical coupling factor and the piezoelectric constant were not so much decreased. The electromechanical coupling factor and the piezoelectric constant were 50％ and 300(${\times}$10$^{-12}$ C/N) respectively. The mechanical quality factor was increased with B$_2$O$_3$. The mechanical quality factor was 1700 at 0.5wt％ B$_2$O$_3$ and sintered at 110$0^{\circ}C$. Dielectric loss was less than 0.5％ regardless of the amount of B$_2$O$_3$.

• Journal of the Korean Chemical Society
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• v.49 no.4
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• pp.377-380
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• 2005

• Korean Journal of Materials Research
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• v.23 no.2
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• pp.104-111
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• 2013

In this study, GaN powders were synthesized from gallium oxide-hydroxide (GaOOH) through an ammonification process in an $NH_3$ flow with the variation of $B_2O_3$ additives within a temperature range of $300-1050^{\circ}C$. The additive effect of $B_2O_3$ on the hexagonal phase GaN powder synthesis route was examined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transformation infrared transmission (FTIR) spectroscopy. With increasing the mol% of $B_2O_3$ additive in the GaOOH precursor powder, the transition temperature and the activation energy for GaN powder formation increased while the GaN synthesis limit-time ($t_c$) shortened. The XPS results showed that Boron compounds of $B_2O_3$ and BN coexisted in the synthesized GaN powders. From the FTIR spectra, we were able to confirm that the GaN powder consisted of an amorphous or cubic phase $B_2O_3$ due to bond formation between B and O and the amorphous phase BN due to B-N bonds. The GaN powder synthesized from GaOOH and $B_2O_3$ mixed powder by an ammonification route through ${\beta}-Ga_2O_3$ intermediate state. During the ammonification process, boron compounds of $B_2O_3$ and BN coated ${\beta}-Ga_2O_3$ and GaN particles limited further nitridation processes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.765-769
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• 2001

Starches of flavored glutinous rice were analyzed by using scanning electron microscope (SEM) and differential scanning calorimetry (DSC) and tested on the starch granule susceptibility to 15% H$_2$SO$_4$, glucoamylase and $\alpha$-amylase. The shape of starch granules form flavored glutinous rice varieties was polygonal and the size was 4~6 $\mu$m in diameter. According to DSC, glutinous rice starch showed onset temperature (T$_{o}$) range 59.8~62.5$^{\circ}C$ and KR92021-B-B-42-3-B and KR92021-B-B-165-1-B showed higher enthalpy ($\Delta$H) on gelatinization than others. The starches from KR92021-B-B-5-2-B and KR92021-B-B-42-3-B showed lower hydrolysis rate using 15% H$_2$SO$_4$ than KR92021-B-B-165-1-B. KR92021-B-B-5-2-B showed higher degree of hydrolysis of glucoamylase and $\alpha$-amylase than the others.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1373-1379
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• 2011

The SLA (Service Level Agreement) is once determined between service provider and users in B3G networks so that the network service must be provided as QoS management. Here, the network situation is changed as the time flow, and the service environment is also altered. Hence, dynamic QoS management scheme should be considered. In this paper, we propose a handover scheme for dyanamic QoS as the network situation in B3G networks. The heterogeneous networks can be used for dynamic QoS management in B3G networks.

• Journal of the Korean Chemical Society
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• v.23 no.2
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• pp.65-74
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• 1979

An effect of the spin-orbit coupling interaction of ligand orbitals on the ground state for octahedral $[Ti(Ⅲ)A_3B_3]$, $ [V(Ⅲ)A_3B_3]$, $ [Fe(Ⅲ)A_3B_3]$ and $ [Ni(Ⅱ)A_3B_3]$ type complexes has been investigated in this work, applying the degenerate perturbation theory. The wave functions are not affected but the energy level splitting for the ground state of these complexes by the spin-orbit coupling interaction of ligand orbitals. The extent of effect on the energy level splitting for the ground state is decreased in order Ti(Ⅲ) > V(Ⅲ) > Fe(Ⅲ).