• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.93-96
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• 2001

We have reported to make nanostructured cobalt oxide electrode that have large capacitance over than 400F/g (specific capacitance) and good cycleability. But, It had serious demerits of low voltage range under 0.5V and low power density. Therefore, we need to increase voltage range of cobalt oxide electrode. we report here on the electrochemical properties of sol-gel-derived nanoparticulate cobalt xerogel in 1M KOH solution and aqueous polymeric gel electrolyte. In solution electrolyte, cobalt oxide electrode had over than 250F/g capacitance consisted of EDLC and pseudocapacitance. In gel electrolyte, cobalt oxide electrode had around 100F/g capacitance. This capacitance was only surface EDLC. In solution electrolyte, potassium ion as working ion reacted with both of layers easily. However, In gel electrolyte, reacted with only surface-active layer. Its very hard to reach resistive layer. So, e have studied on pretretmetn of electrode to contain working ions easily. We'll report more details.

• Bulletin of the Korean Chemical Society
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• 제17권8호
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• pp.696-699
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• 1996

Silicate and borosilicate gels were prepared by the sol-gel process and thermally treated in the 150-850 ℃ temperature range. Solid-state 1H MAS and 29Si CP/MAS NMR spectroscopy were used to investigate the effects of heat treatments on the silicate gel to glass conversion process. The 1H NMR isotropic chemical shifts and the relative intensities of hydrogen bonded and isolated silanol groups have been used to access the information concerning the dehydration process on the silicate gel surface. The 29Si NMR isotropic chemical shifts affected by the local silicon environment have been used to determine the degree of crosslinking, i.e. the number of siloxane bonds. These NMR results suggest that the silicate gel to glass conversion process is occurred by two stages which are dependent on the temperature; (1) the formation of particles up to 450 ℃ and (2) the formation of large particles by aggregation of each separated single particle above 450 ℃. In addition, the effects of B atom on the formation of borosiloxane bonds in borosilicates have been discussed.

• Bulletin of the Korean Chemical Society
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• 제19권5호
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• pp.501-503
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• 1998

In this work, we applied the 1D $11^B$ nutation NMR method for the analysis of the local structural environments in powdered borosilicates $(SiO_2-B_2O_3)$. Spin dynamics during a rf irradiation for spin I=3/2 was analytically calculated with a density ma trix formalism. Spectral simulation programs were written in MATLAB on a PC. Two borosilicates prepared by the sol-gel process at different stabilization temperature were used for the 1D $11^B$ nutation NMR experiment. The $11^B$ NMR parameters, quadrupole coupling constants $(e^2qQ/h)$ and asymmetry parameters (η), for each borosilicate were extracted from the nonlinear least-squares fitting. The effects of heat treatments on the local structures of boron sites in borosilicates were discussed.

• Bulletin of the Korean Chemical Society
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• 제19권5호
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• pp.519-524
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• 1998

In this work, we applied the 1D 11B nutation NMR method for the analysis of the local structural environments in powdered borosilicates (SiO2-B2O3). Spin dynamics during a rf irradiation for spin I=3/2 was analytically calculated with a density matrix formalism. Spectral simulation programs were written in MATLAB on a PC. Two borosilicates prepared by the sol-gel process at different stabilization temperature were used for the 1D 11B nutation NMR experiment. The 11B NMR parameters, quadrupole coupling constants (e2qQ/h) and asymmetry parameters (η), for each borosilicate were extracted from the nonlinear least-squares fitting. The effects of heat treatments on the local structures of boron sites in borosilicates were discussed.

• 한국자원식물학회지
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• 제21권6호
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• pp.427-430
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• 2008

Here we reported two unrecorded naturalized species from Korean flora. Andropogon virginicus L. of Graminaeae and Euphorbia postrata Aiton of Euphorbiaceae are collected from Dong-gu, Ulsan-si and Sinjindo-ri, Taean-gun, Chungcheongnam-do respectively. A. virginicus L. was easily distinguishable from Themeda triandras var. japonica Makino by keel on glume, 2-4 racemes and long hairy rachis. Thus, the new Korean name, 'Na-do-sol-sae', was given. E. postrata Aiton was cleary distinguished from related taxa by hairs on only edges of fruits. The new Korean name, 'Nu-un-ttang-bin-dae' was given considering the species epithet. Descriptions, illustrations and photographs showing habitat were given.

• 공업화학
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• 제21권2호
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• pp.162-168
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• 2010

최근에 염료감응형 태양전지(dye-sensitized solar cells, DSSCs)의 에너지 변환 효율을 증가시키기 위한 방법으로 흡착된 염료에서 발생되는 광전자가 전해질 속의 산화/환원되는 요오드 이온($I_3^-/I^-$)과의 재결합(recombination)을 방지하기 위하여 발생된 광전자를 효율적으로 $TiO_{2}$ 전극을 통해 이동시키는 방법에 관한 연구가 활발히 연구되고 있다. 본 연구에서는 이러한 재결합을 방지하기 위하여, 졸-겔(sol-gel)법으로 합성한 보헤마이트(bohemite) 졸을 이용하여 $TiO_{2}$ 전극에 비해 높은 에너지 밴드갭(band-gap)을 가지고 있는 $Al_2O_3$가 코팅된 이중층의 다공질 나노 $TiO_{2}$ 전극을 제조하고 염료감응형 태양전지에 응용하였다. 특히, 다양한 입자의 크기가 조절된 보헤마이트 졸을 통해 최고의 에너지 변환 효율을 가진 $Al_2O_3$가 코팅된 $TiO_{2}$ 광전극 제조 조건을 조사하였다. 입자 크기 100 nm 보헤마이트 졸로부터 제조한 $Al_2O_3$가 코팅된 $TiO_{2}$ 전극이 순수 $TiO_{2}$로 제조한 광전극 층(7.5%)에 비해 높은 에너지 변환 효율(9.0%)을 보였다.

• 대한전자공학회논문지SD
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• 제39권3호
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• pp.1-8
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• 2002

Sol-gel 법으로 제작한 (Pb/sub 0.9/La/sub 0.1/)Ti/sub 0.975/O₃(PLT (10)) 박막의 구조적 및 전기적 특성에 대한 과잉 Pb 첨가량이 미치는 영향을 조사하였다. DTA 와 X-선 회절분석 결과, 과잉 Pb 첨가량이 7.5 에서 15㏖%로 증가함에 따라, PLT(10) 박막의 결정화 온도는 감소하였으며, (100) 우선 배향성은 증가하였다. 또한, PLT(10) 박막의 과잉 Pb 첨가량에 따른 전기적 특성을 조사한 결과, 12.5㏖% 의 과잉 Pb 를 첨가한 박막이 가장 우수한 전기적 특성을 나타내었다. 이때, 비유전률과 유전손실은 각각 350 과 0.02 이었고, 100㎸/㎝ 에서 누설전류밀도는 1.27×10/sup -6/A/㎠ 이었다. 또한 이력곡선으로부터 구한 잔류분극(p) 과 항전계 (Ec) 는 각각 6.36μC/㎠ 와 58.7㎸/㎝ 이었으며, ±5V 의 사각펄스를 10/sup 9/회 인가한 후에도 잔류 분극값이 초기값의 약 15% 감소하는 비교적 우수한 피로특성을 나타내었다. 이상의 결과로부터, 과잉 Pb 첨가량이 12.5㏖% 인 PLT(10) 박막은 비휘발성 메모리에 응용될 수 있는 매우 유망한 재료임을 알 수 있었다.

• 한국경제지리학회지
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• 제22권4호
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• pp.458-471
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• 2019

DMSP-OLS 야간영상에서 추출된 빛합계지수와 시가지 정보는 사회·경제적 지표 추정과 도시 공간의 역동성 등의 연구에 폭넓게 이용되었다. 본 연구는 1992~2012년 각 연도의 DMSP-OLS 자료를 이용하여 북한과 인접한 중국 지린성 도시들의 경제성장과 시가지 발달의 시·공간적 변화 패턴을 살펴보았다. 지난 20여 년 동안 지린성 빛합계지수 및 각 도시의 빛합계지수는 모두 성장하였다. 또 빛합계지수와 시가지 면적 가중 중심점의 시계열 변화 분석을 한 결과 전자는 북서 방향으로 후자는 남동 방향으로 이동하는 패턴을 따랐다. 이러한 방향성은 중국 정부의 동북진흥전략과 연계된 것으로 추정된다. 향후 연구에서는 DMSP-OLS 자료의 시간적 한계를 극복하기 위한 SNPP VIIRS DNB 영상자료의 공동 활용도 고려되어야 하며, 동시에 경제통계자료와 빛합계지수 간 상관관계에 기반한 회귀모형의 구축을 통해 지역내총생산 등 경제지표의 추정에 관한 연구도 수행되어야 할 것이다.

• 대한화학회지
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• 제61권1호
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• pp.29-33
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• 2017

Formation of Au particles in nonstoichiometric $Cu_{2-x}{^I}Cu{_2}^{II}O_{3-{\delta}}$ ($x{\approx}0.20$; ${\delta}{\approx}0.10$) oxide from aniline + hydrochloric acid mixtures and chloroauric acid in the ratios 30 : 1; 60 : 1; 90 : 1 (S1-S3) by volume and 0.01 mol of copper acetate, $Cu(OCOCH_3)_2.H_2O$, in each case is performed by sol-gel growth. Powder x-ray diffraction (XRD) results show Au particles are dispersed in tetragonal nonstoichiometric dicopper (I) dicopper (II) oxides, $Cu_{2-x}{^I}Cu{_2}^{II}O_{3-{\delta}}$ ($x{\approx}0.20$; ${\delta}{\approx}0.10$). Average crystallite sizes of Au particles determined using Scherrer equation are found to be in the approximate ranges ${\sim}85-140{\AA}$, ${\sim}85-150{\AA}$ and ${\sim}80-150{\AA}$ in S1-S3, respectively which indicate the formation of Au nano-micro size particles in $Cu_{2-x}{^I}Cu{_2}^{II}O_{3-{\delta}}$ ($x{\approx}0.20$; ${\delta}{\approx}0.10$) oxides. Hysteresis behaviour at 300 K having low loop areas and magnetic susceptibility values ${\sim}5.835{\times}10^{-6}-9.889{\times}10^{-6}emu/gG$ in S1-S3 show weakly ferromagnetic nature of the samples. Broad and isotropic electron paramagnetic resonance (EPR) lineshapes of S1-S4 at 300, 77 and 8 K having $g_{iso}$-values ${\sim}2.053{\pm}0.008-2.304{\pm}0.008$ show rapid spin-lattice relaxation process in magnetic $Cu^{2+}$ ($3d^9$) sites as well as delocalized electrons in Au ($6s^1$) nano-micro size particles in the $Cu_{2-x}{^I}Cu{_2}^{II}O_{3-{\delta}}$ ($x{\approx}0.20$; ${\delta}{\approx}0.10$) oxides. Broad and weak UV-Vis diffuse reflectance optical absorption band ~725 nm is assigned to $^2B_{1g}{\rightarrow}^2A_{1g}$ transitions, and the weak band ~470 nm is due to $^2B_{1g}{\rightarrow}^2E_g$ transitions from the ground state $^2B_{1g}$(${\mid}d_{x^2-y^2}$>) of $Cu^{2+}$ ($3d^9$) ions in octahedral coordination having tetragonal distortion.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.200-200
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• 2010

In recent times, metal oxide semiconductors thin films transistor (TFT), such as zinc and indium based oxide TFTs, have attracted considerable attention because of their several advantageous electrical and optical properties. There are many deposition methods for fabrication of ZnO-based materials such as chemical vapor deposition, RF/DC sputtering and pulsed laser deposition. However, these vacuum process require expensive equipment and result in high manufacturing costs. Also, the methods is difficult to fabricate various multicomponent oxide semiconductor. Recently, several groups report solution processed metal oxide TFTs for low cost and non vacuum process. In this study, we have newly developed solution-processed TFTs based on Ti-related multi-component transparent oxide, i. e., InTiO as the active layer. We propose new multicomponent oxide, Titanium indium oxide(TiInO), to fabricate the high performance TFT through the sol-gel method. We investigated the influence of relative compositions of Ti on the electrical properties. Indium nitrate hydrate [$In(NO^3).xH_2O$] and Titanium isobutoxide [$C_{16}H_{36}O_4Ti$] were dissolved in acetylacetone. Then monoethanolamine (MEA) and acetic acid ($CH_3COOH$) were added to the solution. The molar concentration of indium was kept as 0.1 mol concentration and the amount of Ti was varied according to weighting percent (0, 5, 10%). The complex solutions become clear and homogeneous after stirring for 24 hours. Heavily boron (p+) doped Si wafer with 100nm thermally grown $SiO_2$ serve as the gate and gate dielectric of the TFT, respectively. TiInO thin films were deposited using the sol-gel solution by the spin-coating method. After coating, the films annealed in a tube furnace at $500^{\circ}C$ for 1hour under oxygen ambient. The 5% Ti-doped InO TFT had a field-effect mobility $1.15cm^2/V{\cdot}S$, a threshold voltage of 4.73 V, an on/off current ratio grater than $10^7$, and a subthreshold slop of 0.49 V/dec. The 10% Ti-doped InO TFT had a field-effect mobility $1.03\;cm^2/V{\cdot}S$, a threshold voltage of 1.87 V, an on/off current ration grater than $10^7$, and a subthreshold slop of 0.67 V/dec.