• 한국해양학회지:바다
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• 제4권3호
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• pp.198-207
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• 1999

시화호 내 5개 정점에서 채취한 주상시료들을 지화학적으로 분석하여 시화방조제 건설이후 퇴적환경 및 중금속오염에 대해 연구하였다. 시화호내 퇴적환경은 유기물의 C/N비와 C/S비에 의해 무산소환경, 산화환경, 그리고 두 환경이 공존하는 지역으로 세분되었다. 산화환원환경을 지배하는 요인은 수심과 퇴적물의 공급차인것으로 사료된다. 주상시료에서 분석된 지화학적 원소중 Mn-U-Mo간의 상관관계는 각 정점간의 산화 환원환경의 지시자로 사용이 가능하다. 주상시료들의 Al과 Ti 함량은 퇴적물특성에 의해 구분되며, 5개 중금속(Cr, Ni, Cu, Zn 및 Pb)함량은 중금속에 의한 오염정도를 지시한다. 중금속의 상대적 함량은 방조제에 가까운 시화호 중심부분에서 보다 안산-반월공단에 가까운 지역에서 높게 축적되어 있다. 특히 주상시료의 표층퇴적물은 시화호 중앙부보다 시화-반월공단쪽이 약 2-8배 정도로 중금속축적이 높다.

• 한국환경과학회지
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• 제23권5호
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• pp.829-837
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• 2014

Titania-supported chromium oxides with different loadings have been embarked in catalytic oxidation of trichloroethylene (TCE) to inquire association of the formation of crystalline $Cr_2O_3$ with catalytic performances. A better activity in the oxidative TCE decomposition at chosen temperatures was represented when chromium oxides ($CrO_x$) had been dispersed on pure anatase-type $TiO_2$ (DT51D) rather than on phase-mixed and sulfur-contained ones such as P25 and DT51. The extent of TCE oxidation at temperatures below $350^{\circ}C$ was a strong function of $CrO_x$ content in $CrO_x$/DT51D $TiO_2$, and a noticeable point was that the catalyst has two optimal $CrO_x$ loadings in which the lowest $T_{50}$ and $T_{90}$ values were measured for the TCE oxidation. This behavior in the activity with respect to $CrO_x$ amounts could be associated with the formation of crystalline $Cr_2O_3$ on the support surface, that is less active for the oxidation reaction, and an easier mobility of the surface oxygen existing in noncrystalline $CrO_x$ species with higher oxidation states, such as $Cr_2O_8$ and $CrO_3$.

• 보존과학회지
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• 제33권2호
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• pp.131-147
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• 2017

본 연구는 김제 동곡마을 도요지에서 출토된 15~17세기 분청사기와 백자에 대하여 색도와 비중 및 흡수율, 미세구조 관찰 등의 물리적 특성, 태토와 유약의 조성에 대한 화학적 특성에 대하여 분석하였다. 물리적 특성에서 가마운영 상황과 제작 시기에 따라 제작기술이 점차 발전되는 변화가 관찰된다. 원료적 측면에서 동곡마을 도요지는 동일기반암에서 생성된 점토를 사용하여 도자기 종류, 생산 가마, 시기 등에 따라 원료를 정제하거나 융제를 첨가하는 등의 제작기법에서 차이를 보인다. 백자는 분청사기와 비교하여 착색제 함량이 평균적으로 1.3% 이상 적고 융제 성분 $K_2O$ 함량이 1.2% 가량 많은 편으로 같은 온도에서 더 쉽게 자화될 수 있는 특징을 보인다. 이와 같은 특성은 생산 시기가 늦어질수록 분명하게 나타난다. 유약은 자기 종류가 아닌 생산 시기에 따라 16세기 이후에는 MgO, $TiO_2$, MnO, $P_2O_5$ 등의 함량이 적게는 3배, 많게는 10배 이상 줄어들어 사용 원료에 차이가 있었던 것으로 추정해 볼 수 있다.

• 한국세라믹학회지
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• 제28권11호
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• pp.897-907
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• 1991

This study was conducted to research the formation and the color development of CoO-ZnO-Fe2O3-TiO2-SnO2 system for the purpose of synthesizing the spinel pigments which are stable at high temperature. After preparing CoO-ZnO-Fe2O3, in which CoO causes the color, as a basic composition, $\chi$CoO.(1-$\chi$)ZnO.Fe2O3 system, $\chi$CoO.(1-$\chi$)ZnO.TiO2 system and $\chi$CoO.(1-$\chi$)ZnO.SnO2 system were prepared with $\chi$=0, 0.2, 0.5, 0.7, 1.0 mole ratio respectively. The manufacturing was carried out at 128$0^{\circ}C$ for 90 minutes. These specimens were analyzed by the reflectance measurement and the X-ray diffraction analysis and the results were summarized as follows: 1. All of the specimens formed the spinel structure and were colored with stable yellow or blue. 2. As the content of CoO and Fe2O3 in the specimens being increased, the reflectance of each specimen was measured becoming lower and the colors were changed from yellow to greyish blue and from blue to dark blue. 3. As the substituting amount of Co2+ ion for Zn2+ ion in $\chi$CoO-ZnO-TiO2-SnO2 system being increased, the colors were changed from blue to greyish blue. The colors were changed from yellow to grayish green owing to the tetrahedral Co2+ ions being increased, the octahedral Co2+ ions being decreased with increasing the amount of Sn4+ ions. 4. CoO-ZnO-Fe2O3-TiO2-SnO2 system, in which Zn2+ was substituted with Co2+ and Fe3+ was substituted with Ti4+ and Sn4+, easily formed the spinel structure without regard to the amount of substitution or the ion owing to the selectivity of the coordination number: 4 of Zn2+, 4 of Co2+, 6 of Fe3+ or 6 of Ti4+ and Sn4+.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1995년도 특별강연 및 추계학술발표 개요집
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• pp.208-211
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• 1995

Five cast gamma titanium aluminides, Ti-45~48%Al-2%Nb-2%Cr (nominal composition in at. %), were laser welded and their weld cracking susceptibilities were evaluated. Laser power, traversing rate and preheat temperature were systematically varied to generate a series of welds exhibiting a wide range of cooling rate ($100^{\circ}C/s-10,000^{\circ}C/s$). As Al content increased and the weld cooling rate decreased, solidification cracking susceptibility increased while solid-state cracking susceptibility decreased. Through laser beam energy input control and preheat, it was determined possible to produce high quality laser welds.

• 한국결정성장학회지
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• 제11권1호
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• pp.38-42
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• 2001

Electric and dielectric(Ba,Sr)$TiO_3$[BST] thin films for emtal-Insulator-Semiconductor(MIS) capacitors have been studied. BST thin films wre deposted on p-Si(100) substrates bythe RF magnetron sputtering with tempratue range of 500~$600^{\circ}C$. The dielectric properties of MIS capacitors consisting of Al/BST/$SiO_2$/Si sandwich structure were evaluated ot redcue the leakage current density. The charge state densities of the MIS capacitors were determined by high frequency (1 MHz) C-V measurement. In order to reduce the leakage current in MIS capacitor, high quality $SiO_2$ layer was deposited on bare p-Si substrate. Depending on the oxygen pressure and substrate temperature both positive and negative polarities of effective oxide charge in the MIS capacitors were evaluated. It is considered that the density of electronic states, generated at the BST/$SiO_2$/p-Si interface due to the asymmetric structure within BST/$SiO_2$/Si structure, and the oxygen vacancy content has influence on the behavior of oxide charge.

• 한국자원식물학회지
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• 제4권2호
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• pp.39-45
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• 1991

Proximate compositions of the roots of cultured and wild Codonopsis lanceolata were examined as tile basic reasearch for the study of their source of processed foods.No significant difference in the contents was found between the wild root and thecultivated at 3$0^{\circ}C$ in biotronroom. In view of the results to have measured mineralswhich is included in 14 sorts of Codonopsis lanceolata and surveyed their distribution.12 kinds of minerals including T1, Co, Ge, Sm, Mo, Sc, Be, Cd, As, Ga, Bi, ph are ne-vel or little included in almost source. Other twenty-one sorts of minerals (Ni, Se,Ba, Sb, Si, Ti, B, Li, Ifs, Ca, Sr, Mn, Fe, Cu, Zn, p, Al, Na, V, Cr, K) are more or less in-cluded in all source and Ca, Mg, p, K, and Fe are metals that are included in large qu-entities in comparison with others. No minerals difference in the contents was foundbetween the cultivated temperature. The content of elements of inorganic metal differsaccording to the part of C. lanceolata.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
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• pp.848-850
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• 1999

In this study, PZT etching was performed using planar inductively coupled Ar(20)/$Cl_2/BCl_3$ plasma, The etch rate of PZT film was 2450 $\AA/min$ at Ar(20)/$BCl_3$(80) gas mixing ratio and substrate temperature of $80^{\circ}C$. X-ray photoelectron spectroscopy (XPS) analysis for film composition was utilized. The chemical bond of PbO is broken by ion bombardment, and the peak of metal Pb in a Pb 4f peak begins to appear upon etching, decreasing Pb content faster than Zr and Ti. As increase content of additive $BCl_3$, the relative content of oxygen decreases rapidly. We thought that abundant Band BCl radicals made volatile oxy-compound such as $B_{x}O_{y}$ and/or $BClO_x$ bond. To understand etching mechanism, Langmuir probe and optical emission spectroscopy (OES) analysis were utilized for plasma diagnostic.

• The Korean Journal of Ceramics
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• 제6권2호
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• pp.116-119
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• 2000

The a-axis and c-axis prefer oriented SBT thin films could be deposited on Pt(111)/Ti/$SiO_2$$650^{\circ}C$). The c-axis preferred orientation of SBT film can be obtained by Sr deficiency and high compressive stress. However, the a-axis-oriented grains can be formed under stoichiometric Sr content and nearly stress-free state.

• Transactions on Electrical and Electronic Materials
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• 제8권6호
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• pp.241-245
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• 2007

[ $(Ba_{0.9-x}Sr_xCa_{0.10})TiO_3$ ] (x=0.33, 0.36) powders were prepared by sol-gel method. $(Ba,Sr,Ca)TiO_3$(BSCT) thick films, undoped and doped with $MnCO_3$ and $Yb_2O_3(0.1{\sim}0.7mol%)$, were fabricated by the screen printing method on the alumina substrate. The coating and drying procedure was repeated 6-times. The Pt bottom electrode was screen printing method on the alumina substrate. These BSCT thick films were annealed at $1420^{\circ}C$ for 2 hr in atmosphere. The upper electrodes were fabricated by screen printing the Ag paste and then firing at $590^{\circ}C$ for 10 min. And then the structured and dielectric properties as a function of the doping amount of $Yb_2O_3$ were studied. As a result of the TG-DTA, exothermic peak was observed at around $670^{\circ}C$ due to the formation of the polycrystalline perovskite phase. All BSCT thick films showed XRD patterns of typical cubic peroveskite structure. The average thickness of BSCT thick films was about $70^{\mu}m$. The curie temperature and the dielectric constant decreased with increasing $Yb_2O_3$ doped content and the relative dielectric constant of the specimen, doped with 0.5 mol% $Yb_2O_3$ at BSCT(54/36/10), showed a best value of 5018 at curie temperature.