• Bulletin of the Korean Chemical Society
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• v.20 no.12
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• pp.1483-1486
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• 1999

The contents of pentachlorophenol (PCP) and 2,3,5,6-tetrachlorophenol (TeCP) in textile products are regulated for safety. Since an organic solvent such as 2-methoxyethanol is needed to extract chlorinated phenols from textile samples, nonaqueous capillary electrophoresis has been applied to achieve the separation of PCP and isomers of TeCP. The run buffer was 100 mM Tris/acetate in methanol whose pH was adjusted to 8.0. All of the analytes were negatively charged at pH 8.0 and their electrophoretic velocities were higher than the electroosmotic flow of the methanol buffer. A reverse voltage of -20 kV was applied along a 27-cm fused silica capillary with ID of 50 μm, and PCP and 3 TeCP isomers were separated based on the difference in $pK_a$ values in less than 4 min. The limits of detection (S/N = 3) were about 0.02 μM. By varying pH of the methanol run buffer, $pK_a$ values of the 4 chlorinated phenols were also estimated.

• Progress in Medical Physics
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• v.23 no.2
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• pp.71-80
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• 2012

In order to verify exact dose distributions in the state-of-the-art radiation techniques, a newly designed three-dimensional dosimeter and technique has been took strongly into consideration. The main purpose of our study is to verify the optimized parameters of polymer gel as a real volumetric dosimeter in terms of the various study of MRI. We prepared a gel dosimeter by combing 8% of gelatin, 8% of MAA, and 10 mM of THPC. We used a Co-60 gamma-ray teletherapy unit and delivered doses of 0, 2, 4, 6, 8, 10, 12, and 14 Gy to each polymer gel with a solid phantom. We used a fast spin-echo pulse to acquire the characterized T2 time of MRI. The signal noise ratio (SNR) of the head & neck coil was a relatively lower sensitivity than the body coil; therefore the dose uncertainty of head & neck coil would be lower than body coil's. But the dose uncertainty and resolution of the head & neck coil were superior to the body coil in this study. The TR time between 1,500 ms and 2,000 ms showed no significant difference in the dose resolution, but TR of 1,500 ms showed less dose uncertainty. For the slice thickness of 2.5 mm, less dose uncertainty of TE times was at 4 Gy, as well, it was the lowest result over 4 Gy at TE of 12 ms. The dose uncertainty was not critical up to 6 Gy, but the best dose resolution was obtained at 20 ms up to 8 Gy. The dose resolution shows the lowest value was over 20 ms and was an excellent result in the number of excitation (NEX) of three. The NEX of two was the highest dose resolution. We concluded that the better result of slice thickness versus NEX was related to the NEX increment and thin slice thickness.

• Journal of Haehwa Medicine
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• v.15 no.2
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• pp.193-199
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• 2006

The literatural study on the effect of acupuncture for tinnitus was studied from the viewpoint of acupuncture effect. The conclusions are as follows. 1. The ear manages kidney, it relates with the heart meridian of hand soeum, kidney meridian of foot soeum, lung meridian of hand taeeum, spleen meridian of foot taeeum, stomach meridian of foot yangmyeong, gallbladder meridian of foot soyang, triple energizer meridian of hand soyang, small intestine meridian of hand taeyang. 2. According to classification of meridian in acupuncture treatment of tinnitus triple energizer meridian of hand soyang 18.0%, gallbladder meridian of foot soyang 16.6%, bladder meridian of foot taeyang 16.6%, small intestine meridian of hand taeyang 9.7%, large intestine meridian of hand yangmyeong 8.3%, stomach meridian of foot yangmyeong 5.5%, spleen meridian of foot taeeum 4.1%, pericardium meridian of hand gworeum 4.1%, lung meridian of hand taeeum 2.8%, heart meridian of hand soeum 2.8%, kidney meridian of foot soeum 2.8%, liver meridian of foot gworeum 2.8%, conception channel 2.8%, governor channel 2.8% have been used much in turn. 3. In the general points GB2 24times, TE3 22times, TE17 22times, SI19 20times, TE21 20times, KI 3 19times, BL23 17times, LI4 15times have been used much in turn.

• Electrical & Electronic Materials
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• v.29 no.6
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• pp.22-27
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• 2016

• Proceedings of the Membrane Society of Korea Conference
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• 1997.10a
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• pp.51-52
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• 1997

1. 서론 : 폴리이미드는 우수한 기계적 강도와 열적, 화학적 안정성으로 인해 최근 막분리 재료로 많이 연구 검토되고 있다. 대부분의 폴리이미드는 비교적 높은 선택도를 가지고 있으나 투과계수가 떨어지는 단점을 지니고 있어소 이를 극복하기 위한 많은 연구가 진행되어 왔다. 그 결과 투과계수를 크게 증가시킨 폴리이미드를 함성하였으나 선택도는 감소하여 투과특성의 상위한계를 넘지는 못하였다. 이 한계를 극복하기 의해서 복합잴를 이용하거나 UV, 플라즈마 처리에 의한 고분자막의 수식 등 많은 방법들이 연구되고 있다. 본 연구는 NaX형 제올라이트를 폴리이미드에 혼화시킨 막으로 산소/질소의 분리투과특성의 개선을 시도하였으며, NaX형 제올라이트와 폴리이미드 혼화방법, 혼화비율 등이 기체투과특성에 미치는 영향을 고찰하였다. 본 실험에 사용된 NaX형 제올라이트는 직접 합성하여 사용하였다. 폴리이미드는 2,3,5,6-Tetramethyl-1,4-phenylenediamine(p-TeMPD)과 (3,3,4,4'-dicarboxyphenyl)-hexafluoropropene-dianhydride(6FDA)로 합성한 6FDA-p-TeMPD 폴리이미드를 사용하였고, 그 투과계수는 122Barrer, 선택도$\alpha$$_{N_2/O_2}$ = 3.4이다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6B
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• pp.1068-1073
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• 2000

In this paper, we propose a serially concatenated turbo bode/turbo equalizer scheme for optical storage systems. Without modulation coding, a random data sequence is directly passed through the optical channel. In simulation, the channel includes jitter of 15% and AWGN. The densities of the channel are S=4.6 and S=7.0. The code rates of turbo code are 4/5, 8/9 and 16/17. All code rates, the bit error probability is less than 10-5 at 24dB when we and jitter of 15%.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.10a
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• pp.28-29
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• 1994

일반적으로 polyimide는 열적, 화학적으로 안정하며 좋은 기계적 성질을 갖고 있고 기체투과 특성이 뛰어나므로 훌륭한 막 소재로 알려져 있다. 그러나, 높은 선택도를 나타내면 투과도가 떨어지고 투과도가 높으면 선택도가 떨어지는 일반적인 고분자 막이 보이는 경향을 따르므로, 본 연구에서는 이례적으로 높은 산소 투과도를 보이는 6FDA-pTeMPD polyimide와 높은 선택도를 나타내는 6FDA-mPDA polyimide을 공중합 시킴으로써 각각의 homopolyimide로서는 얻을수 없는 개선된 기체 투과도와 선택도를 얻을 수 있으리라 예상하여 연구를 하였다. 조성과 자유용적, 조성과 Tg관계, 조성과 투과도 및 선택도를 조사하여 공중합 하였을때 고분자의 화학 구조와 미시적 구조간의 관계를 규명하여 분자 설계로 적절한 막 특성을 갖는 공중합 막을 합성할 수 있는 정보를 확립하였다.

• Korean Journal of Materials Research
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• v.7 no.5
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• pp.374-380
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• 1997

열전재료 분말을 AI관에 진공봉입하고 형틀가입한 후 소결하는 새로운 방법으로 n형 B $i_{2}$T $e_{2.4}$S $e_{0.6}$를 제조하여 소결조건에 따른 소결성과 열전특성을 조사.분석하였다. AI은 소결시 열전재료와 반응하지 않아 보호 용기로 적합하였으며, 평균입도 195$\mu\textrm{m}$의 분말을 사용하여 성형압 280 MPa, 온도 400에서 50$0^{\circ}C$에서 소결할 경우 성능지수는 1.9x $10^{-3}$K였다.다.

• Korean Journal of Materials Research
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• v.20 no.6
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• pp.326-330
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• 2010

$CoSb_3$ Skutterudites materials have high potential for thermoelectric application at mid-temperature range because of their superior thermoelectric properties via control of charge carrier density and substitution of foreign atoms. Improvement of thermoelectric properties is expected for the ternary solid solution developed by substitution of foreign atoms having different valances into the $CoSb_3$ matrix. In this study, ternary solid solutions with a stoichiometry of $Co_{1-x}Ni_xSb_3$ x = 0.01, 0.05, 0.1, 0.2, $CoSb_{3-y}Te_y$, y = 0.1, 0.2, 0.3 were prepared by the Spark Plasma Sintering (SPS) system. Before the SPS synthesis, the ingots were synthesized by vacuum induction melting and followed by annealing. For phase analysis X-ray powder diffraction patterns were checked. All the samples were confirmed as single phase; however, with samples that were more doped than the solubility limit some secondary phases were detected. All the samples doped with Ni and Te atoms showed a negative Seebeck coefficient and their electrical conductivities increased with the doping amount up to the solubility limit. For the samples prepared by SPS the maximum value for dimensionless figure of merit reached 0.26, 0.42 for $Co_{0.9}Ni_{0.1}Sb_3$, $CoSb_{2.8}Te_{0.2}$ at 690 K, respectively. These results show that the SPS method is effective in this system and Ni/Te dopants are also effective for increasing thermoelectric properties of this system.

• Korean Journal of Optics and Photonics
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• v.8 no.2
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• pp.149-153
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• 1997

We demonstrate the operating characteristics(center wavelength, bandwidth, TE/TM polarization, tuning range) of grating-assisted co-directional coupler(GACC) filter fabricated with InGaAsP compound semiconductor. A design of waveguide structure has been focused on the narrow bandwidth characteristics of the filter. Reactive ion etching technique was employed for the uniform waveguide formation. The bandwidths(FWHM) and center wavelengths of the fabricated GACC filter were measured by 1.5 nm and 1530.6 nm for TE polarization and 1.3 nm and 1494.0 nm for TM polarization. This is the one of the narrowest bandwidth at 1530 nm region ever reported. The center wavelength shifted form 1530 nm to 1538 nm when the current of 100 mA was injected at 4.5 mm-long device. Good agreement between the designed and measured operating characteristics for some waveguide structures is demonstrated.