• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.3021-3024
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• 2009

$Zn_2Ti_{1-x}Fe_xO_4\;(0\;{\leq}\;x\;{\leq}\;0.7)$ photocatalysts were synthesized by polymerized complex (PC) method and investigated for its physico-chemical as well as optical properties. $Zn_2Ti_{1-x}Fe_xO_4$ can absorb not only UV light but also visible light region due to doping of Fe in the Ti site of $Zn_2TiO_4$ lattice because of the band transition from Fe 3d to the Fe 3d + Ti3d hybrid orbital. The photocatalytic activity of Fe doped $Zn_2TiO_4$ samples for hydrogen production under UV light irradiation decreased with an increase in Fe concentration in $Zn_2TiO_4$. Consequently, there exists an optimized concentration of iron for improved photocatalytic activity under visible light (${\lambda}{\leq}$420 nm)

• E2M - 전기 전자와 첨단 소재
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• 제5권4호
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• pp.406-410
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• 1992

본 논문에서는 MgFe$_{2}$O$_{4}$ 세라믹스의 구조적 특성을 개선하기 위하여 TiO$_{2}$를 0-10[wt%] 첨가하여 세라믹스를 만들고 TiO$_{2}$가 습도센서용 MgFe$_{2}$O$_{4}$ 세라믹스의 구조적 특성에 미치는 영향을 조사하였다. 각 시편은 TiO$_{2}$가 첨가되는 양이 증대함에 따라 NgTi$_{2}$O$_{5}$의 이상이 나타났다. TiO$_{2}$의 첨가량이 6[wt%]일 때 까지는 시편의 밀도가 증가하여 기공율의 저하를 가져왔고 기공의 크기가 최소가 되는 조성은 5[wt%]의 TiO$_{2}$가 첨가되었을 때이며 이때의 평균 기공의 크기는 1615[.angs.]이었다. 따라서 5[wt%]의 TiO$_{2}$를 첨가했을 때가 기공의 크기 조절에 최적이라고 생각되며 센서용 기판으로 응용하기 적합하다고 생각된다.

• 대한금속재료학회지
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• 제50권11호
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• pp.855-859
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• 2012

Samples with compositions of 80 wt% Mg-14 wt% Ni-6 wt% $Fe_2O_3$ and 80 wt% Mg-14 wt% Ni-6 wt% Ti were prepared by mechanical grinding under hydrogen (reactive mechanical grinding). Their hydrogen absorptions during reactive mechanical grinding were examined. TGA and BET analysis were employed to investigate the hydrogen storage properties of the prepared alloys. TGA analysis of the $Mg-14Ni-6Fe_2O_3$ showed an absorbed hydrogen quantity of 6.91 wt% while that of Mg-14Ni-6Ti was 2.59 wt%. BET analysis showed that the specific surface areas of $Mg-14Ni-6Fe_2O_3$ and Mg-14Ni-6Ti after reactive mechanical grinding were $264m^2/g$ and $64m^2/g$, respectively. The larger absorbed hydrogen quantity and the larger specific surface area of $Mg-14Ni-6Fe_2O_3$ after RMG than those of Mg-14Ni-6Ti after RMG showed that the effects of $Fe_2O_3$ addition are much stronger than those of Ti addition during reactive mechanical grinding.

• 한국재료학회지
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• 제20권5호
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• pp.246-251
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• 2010

The composite photocatalysts of a Fe-modified carbon nanotube (CNT)-$TiO_2$ were synthesized by a two-step sol-gel method at high temperature. Its chemical composition and surface properties were investigated by BET surface area, scanning electron microscope (SEM), Transmission Electron Microscope (TEM), X-ray diffraction (XRD) and ultraviolet-visible (UV-Vis) spectroscopy. The results showed that the BET surface area was improved by modification of Fe, which was related to the adsorption capacity for each composite. Interesting thin layer aggregates of nanosized $TiO_2$ were observed from TEM images, probably stabilized by the presence of CNT, and the surface and structural characterization of the samples was carried out. The XRD results showed that the Fe/CNT-$TiO_2$ composites contained a mix of anatase and rutile forms of $TiO_2$ particles when the precursor is $TiOSO_4{\cdot}xH_2O$ (TOS). An excellent photocatalytic activity of Fe/CNT-$TiO_2$ was obtained for the degradation of methylene blue (MB) under visible light irradiation. It was considered that Fe cation could be doped into the matrix of $TiO_2$, which could hinder the recombination rate of the excited electrons/holes. The photocatalytic activity of the composites was also found to depend on the presence of CNT. The synergistic effects among the Fe, CNT and $TiO_2$ components were responsible for improving the visible light photocatalytic activity.

• Metals and materials international
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• 제24권6호
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• pp.1213-1220
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• 2018

The effects of Cr and Fe addition on the mechanical properties of Ti-6Al-4V alloys prepared by direct energy deposition were investigated. As the Cr and Fe concentrations were increased from 0 to 2 mass%, the tensile strength increased because of the fine-grained equiaxed prior ${\beta}$ phase and martensite. An excellent combination of strength and ductility was obtained in these alloys. When the Cr and Fe concentrations were increased to 4 mass%, extremely fine-grained martensitic structures with poor ductility were obtained. In addition, Fe-added Ti-6Al-4V resulted in a partially melted Ti-6Al-4V powder because of the large difference between the melting temperatures of the Fe eutectic phase (Ti-33Fe) and the Ti-6Al-4V powder, which induced the formation of a thick liquid layer surrounding Ti-6Al-4V. The ductility of Fe-added Ti-6Al-4V was thus poorer than that of Cr-added Ti-6Al-4V.

• 한국자원식물학회지
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• 제20권1호
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• pp.12-21
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• 2007

토양에서 화강암 지역은 $Al_2O_3,\;Na_2O$, 천매암 지역은 $Fe_2O_3,\;MnO,\;MgO$, 혈암 지역은 $SiO_2,\;CaO$에서 높았다. 이 화강암 지역과 천매암 토양의 원소 특성은 이들 토양 중의 광물 차이를 반영한다. 상관관계에서 화강암, 천매암, 혈암 3지역 공히, 정의 관계가 $Al_2O_3-K_2O,\;Fe_2O_3-MgO$ 쌍에서, 부의 관계가 $SiO_2-CaO$ 쌍에서 나타났다. 인삼에서 동일 연생 인삼의 지역적 비교 시 2, 3년에 관계없이 혈암 지역이 높은 함량 원소가, 화강암 지역이 낮은 함량의 원소가 많았다. 즉 2년생은 천매암 지역의 Fe, Ca, 혈암 지역의 Al, Mn, Na, Ti에서, 3년생은 화강암 지역의 Mn, Na, 천매암 지역의 Ca, 혈암 지역의 Al, Fe, Ti에서 높은 값이 나타났다. 같은 지역 인삼의 연생 차이별 비교에서 3지역 공히 2년생에서 Al, Na, Ti가 높았다. 또한 화강암 지역은 2년생의 Al, Mn, Mg, Na, Ti, 3년생의 Fe, Ca에서, 천매암 지역은 2년생의 Al, Fe, Mg, Ca, Na, Ti, 3년생은 Mn, K에서 높았다. 지상부의 무기성분 함량에 대한 2, 3년의 지역 별 비교에서 혈암 지역이 높은 원소가 많았고 화강암 지역이 낮은 원소가 많았다. 2년생의 경우 화강암 지역은 Ca, 천매암 지역은 Fe, Ca, 혈암 지역은 Al, Mn, Na, Ti에서, 3년생의 화강암 지역은 Mn, 천매암 지역은 Ca, 혈암 지역은 Al, Fe에서 높았다. 상관관계에서 2, 3년생의 경우 공히 Al-Ti, Mn-Na쌍에서 정의 관계가 나타났다. 뿌리의 무기성분 함량에서 2년생은 화강암 지역에서 높은 원소가 많았고, 천매암 지역이 낮은 원소가 많았다. 3년생은 혈암 지역에서 높은 원소가 많았고, 천매암 지역이 낮은 원소가 많았다. 즉 2년생은 화강암의 Al, Mn, Na, 천매암 지역의 Fe, Ca, 혈암지역의 Ti에서, 3년생은 화강암 지역의 Ca, Na, 혈암 지역의 Al, Fe, Mn, Ti에서 높았다. 2년생은 화강암 지역의 Fe, 천매암 지역의 Al, Mn, Na, Ti, 혈암 지역의 Ca, 3년생은 화강암 지역의 Fe, 천매암 지역의 Al, Mn, Na, Ti, 혈암 지역의 Ca, K에서 낮았다. 지상부와 뿌리 부분 비교에서 지역에 관계없이 수 배 차이로 Fe, Mn, Ca는 지상부가, Ti는 하부가 높았다. 지역에 관계없이 Mn, Ca, Fe, Al, Na, Ti 순서로 지상/하부 비율이 내려갔다. 토양과 인삼의 무기성분 함량관계에서 지역에 관계없이 Ca는 수 십 배의 차이로, Mn는 수 배에서 수 십 배 차이로 인삼이 높았고, Na, Fe, Ti, Al은 수배의 차이로 토양이 높았다. 인삼과 토양의 비에서 대부분 지역이 2년생이 크고 3년생이 작았으며, 지역에 관계없이 공히 Al, Mn, Na는 2년생이 크고 3년생이 작았다. 이 결과는 인삼의 연령이 증가함에 따라 토양 중 원소를 흡수하여, 더욱더 토양의 특성을 반영하기 때문으로 생각된다.

• 한국자기학회지
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• 제5권5호
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• pp.570-574
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• 1995

Magnetoresistance of NiFeCo/Cu/NiFeCo/FeMn uncoupled exchange biased sandwiches has been studied. The magnetoresistance change ratio, ${\Delta}R/R_{s}$ showed 4.1 % at a saturation field as low as 11 Oe in $Si/Ti(50\;{\AA})/NiFeCo(70\;{\AA})/Cu(23\;{\AA})/NiFeCo(70\;{\AA})/FeMn(150\;{\AA})/Cu(50\;{\AA})$ spin valve structure. In this system, the magnetoresistance was affected by interlayer material and thickness. When Ti and Cu were used as the interlayer material in this structure, maximum magnetoresistance change ratio were 0.32 % and 4.1 %, respectively. 6.1 % MR ratio was obtained in $Si/Ti(50\;{\AA})/NiFeCo(70\;{\AA})/Cu(15\;{\AA})/NiFeCo(70\;{\AA})/FeMn(150\;{\AA})/Cu(50\;{\AA})$ spin valve structure. The magnetoresistance change ratio decreased monotonically as the interlayer thickness increased. It was found that the exchange bias field exerted by FeMn layer to the adjacent NiFeCo layer was ~25 Oe, far smaller than that reported in NiFe/Cu/NiFe/FeMn spin valve structure(Dieny et. al., ~400 Oe). The relationship between the film texture and exchange anisotropy ha been examined for spin valve structures with Ti, Cu, or non-buffer layer.

• 한국전기전자재료학회논문지
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• 제19권6호
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• pp.519-523
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• 2006

$LiFePO_4$ has been received attention as a potential cathode material for the lithium secondary batteries. In our study, $LiFePO_4$ cathode active materials were synthesized by a solid-state reaction. It was modified by coating $TiO_2$ and carbon in order to enhance cyclic performance and electronic conductivity. $TiO_2$ and carbon coatings on $LiFePO_4$ materials enhanced the electronic conductivity and its charge/discharge capacity. For lithium polymer battery applications, $LiFePO_4$/solid polymer electrolyte (SPE)/Li and $LiFePO_{4}-TiO_{2}/SPE/Li$ cells were characterized by a cyclic voltammetry and charge/discharge cycling. The electrode with $LiFePO_{4}-carbon-TiO_{2}$ in PVDF-PC-EC-$LiClO_{4}$ electrolyte showed promising capacity of above 100 mAh/g at 1C rate.

• 한국주조공학회지
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• 제29권2호
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• pp.59-63
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• 2009

Effects of Ti on damping capacity and mechanical properties are investigated in hot rolled Fe-17%Mn alloy. The existing damping alloy with Fe-Mn binary system was limited the use by high production cost, however in case of using scrap iron instead of pure iron although the content of carbon is higher it is possible to be applied wider field especially construction items because the production cost is lower. However, the excellent specific damping capacity is dropped due to the high content of carbon, we developed advanced type of damping alloy included Ti. TiC is formed with added Ti and it holds the specific damping capacity similar to existing damping alloy. The effect of Ti on damping capacity is found to be beneficial in carbon-containing alloy, which is attributed to the depletion of carbon solute due to the formation of TiC.

• 한국광물학회지
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• 제2권1호
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• pp.8-10
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• 1989

Sphene from the McDonald pegmatite near Bancroft, Ontario, Canada was analyzed using EPMA. It contains 4.3 to 6.3 weight percent of Nb2O5 with an average formula Ca1.02(Ti0.62Al0.22Nb0.07Fe0.06Ta0.01)Si0.99(O4.85F0.16). Three types of subtitutions are possible; 1)2Ti4+=(Nb, Ta)5+ + (Al, Fe3+), 2) Ti + O = (Al, Fe3+) + (F, OH), and 3) 2Ti + O = Fe2+ + (Nb, Ta)5+ + (F, OH). T재 different schemes of substitutions for balancing the analysis are considered when the iron is either all ferric or all ferrous. Assuming stoichiometry fo Ca and Si, a general formula derived from the two different schemes is Ca(Ti0.64Al0.22Fe3+0.06-X {{{{Fe_{x}^{2+} }} Nb0.01)Sio4.80-XF0.16(OH)0.04+x.