• 대한방사성의약품학회지
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• 제3권2호
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• pp.103-112
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• 2017

The combination of nanoparticle with radioisotope could give the in vivo information with high sensitivity and specificity. However, radioisotope labeling of nanoparticle is very difficult and radioisotopes have different physicochemical properties, so the radioisotope selection of nanoparticle should be carefully considered. $^{18}F$ was first option to be considered for labeling of nanoparticle. For the labeling of $^{18}F$ with nanoparticle, Prosthetic group is widely used. Iodine, another radioactive halogen, is often used. Since radioiodine isotopes are various, they can be used for different imaging technique or therapy in the same labeling procedures. $^{99m}Tc$ can easily be obtained as pertechnatate ($^{99m}{TcO_4}^-$) by commercial generator. Ionic $^{68}Ga$ (III) in dilute HCl solution is also obtained by generator system, but $^{68}Ga$ can be substituted for $^{67}Ga$ because of the short half-life (67.8 min). $^{64}Cu$ emits not only positron but also ${\beta}-particle$. Therefore $^{64}Cu$ can be used for imaging and therapy at the same time. These radioactive metals can be labeled with nanoparticle using the bifunctional chelator. $^{89}Zr$ has longer half-life (78.4 h) and is used for the longer imaging time. Unlike different metals, $^{89}Zr$ should use the other chelate such as DFO, 3,4,3-(LI-1,2-HOPO) or DFOB.

• Elastomers and Composites
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• 제48권4호
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• pp.263-268
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• 2013

본 연구에서는 다리 구조의 메탈로센 촉매인 rac-$Et[Ind]_2ZrCl_2$를 이용하여 새로운 구조의 poly(ethylene-ter-1-hexene-ter-divinylbenzene) 삼원공중합체를 제조하였다. 공단량체인 1-hexene이 중합에 미치는 효과에 관한 연구를 수행하였다. 여러 가지 중합 조건의 영향을 살펴보았는데 공촉매/촉매 몰비가 3,000일 때, 촉매활성도는 8,000이 넘는 매우 높은 수준의 활성도를 보여주었다. 또한, 중합 시간에 따라 중량 평균 분자량이 일정 수준까지 증가하는 경향을 나타내었고, 중합시간이 50분일 때는 무정형 상태에 가까워지는 것을 확인하였다. 삼원공중합체의 중량 평균 분자량은 110,000-200,000, 밀도는 $0.85-0.89g/cm^3$ 수준이었다. 또한, 삼원 공중합체의 열적 성질과 구조를 확인하였다.

• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3352-3358
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• 2023

Nuclear medicine seems to be a decent choice of medicine in the recent decade. The radioactive isotopes ⁵¹Cr, ⁸⁹Sr, ⁹⁹Tc, ¹³¹I, ¹³³Xe, ¹³⁷Cs and ¹⁵³Sm are extremely essential in nuclear medicine. The excitation functions of the ⁵⁴Fe (n, α) ⁵¹Cr, ⁹²Zr (n, α) ⁸⁹Sr, ¹⁰²Rh (n, α) ⁹⁹Tc, 134Cs (n, α) ¹³¹I, ¹³⁶Ba (n, α) ¹³³Xe, ¹⁴⁰La (n, α) ¹³⁷Cs and ¹⁵⁶Gd (n, α) ¹⁵³Sm reactions were calculated in this study using the EMPIRE 3.2.3 and TALYS 1.95 nuclear codes. Additionally, the cross sections at 14-15 MeV were calculated using empirical formulae and the experimental data. The computer codes were compared to the experimental data and Empirical formulas as well as the evaluated data (TENDL 2021, JENDL 3.3, JENDL 5, JEFF 3.3, EAF 2010, CENDL 3.1, CENDL 3.2, ROSFOND 2010, FENDL 3.2 b, and BROND 3.1).

• 한국세라믹학회지
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• 제45권12호
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• pp.760-765
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• 2008

In this study, the effects of small amounts (${\leq}3\;mol%$) of Li doping on the sintering characteristics and electrochemical performance of $(ZrO_2)_{0.89}(ScO_{1.5})_{0.1}(CeO_2)_{0.01}$ (ScSZ) were investigated. By adding 3 mol% lithium, the densification temperature of ScSZ was reduced from the conventional temperature of $1400^{\circ}C$ to $1200^{\circ}C$. It was found that Li doping also led to changes in the Zr:Sc ratio at the grain boundaries. Correspondingly, the dispersion of lithium zirconia at the grain boundaries accelerated the growth of ScSZ grains and increased the grain boundary resistance at temperatures below $450^{\circ}C$. At elevated temperatures of $450{\sim}750^{\circ}C$, the electrical conductivity of the ScSZ after doping remained almost unchanged under air and reducing atmospheres. These results suggest that the addition of lithium is promising for use in low temperature co-firing of ScSZ-based components for intermediate temperature solid oxide fuel cells.

• Bulletin of the Korean Chemical Society
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• 제35권1호
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• pp.236-242
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• 2014

Isospecific propylene polymerization behavior of meta- and para-Lewis base (E) functionalized unbridged zirconocenes ($[1-(E_n-Ph)-3,4-Me_2C_5H_2]_2ZrCl_2$, E = $NMe_2$, OMe; n = 1 or 2) was investigated under bulk conditions. Catalytic activity of the zirconocenes, and molecular weight and isotacticity of polypropylenes are found to be dependent on the position and number of the Lewis base functional groups in the zirconocenes. All the crude polypropylenes possess a broad molecular weight distribution and multi-melting transitions, indicating an involvement of multi-catalytic active species in the polymerization. The highest [mmmm] value of an isotactic portion of the polypropylenes reached 89%, which is higher than that (85%) from the well-known $C_2$-symmetric EBIZr (rac-$Et(Ind)_2ZrCl_2$) catalyst. These results support that the in situ generated, rigid rac-like cation-anion pair through the Lewis acid-base interactions between the functional groups of zirconocenes and methylaluminoxane anion is effective in the formation of isotactic polypropylene under bulk propylene polymerization conditions.

• 한국재료학회지
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• 제7권6호
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• pp.536-544
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• 1997

본연구는 45 BaO-20B$_{2}$O$_{3}$-35Fe$_{2}$o$_{3}$(wt%)의 조성의 유리에 핵형성제로서 TiO$_{2}$또는 ZrO$_{2}$를 첨가한 조성에서는 barium ferrite(BaFe$_{12}$O$_{19}$)가 결정화되었다. TiO$_{2}$를 9wt%첨가한 조성에 대하여 활성화에너지와 진동수는 각각 235.45kJ/mol, 진동수 6.89x$10^{17}$S$^{-1}$이었으며, Avrami지수는 1$\leq$n $\leq$로서 일방향의 결정성장으로 나타났다. 또한, ZrO$_{2}$9wt% 첨가 조성에서는, 활성화에너지와 진동수는 각각 173.86kJ/mol, 2.65x$10^{14}$S$^{-1}$이었으며, Avrami지수는 2$\leq$n$\leq$3로서 이방향의 결정성장을 나타내었다.내었다.

• 한국해양학회지
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• 제6권1호
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• pp.1-15
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• 1971

동해에서 채취한 97개 해저토의 Zr, Br, Ni, Sr, Zn, Mn, Ti 및 Fe등 8개성분의 함량을 Fluorescence Spectrometer 에 의해서 분석하여 이것들의 함유량을 조사하고 그 해역분포에 관해서 고찰하였다. 1. Zr의 함량은 22-962ppm(평균 194.4ppm)이고, 남부 대륙붕 해저에서는 St. 75부근에 고농도지대가 형성되나, 영일만 이북 해역에서는 연안성 해저토의 함량이 크고 심해 해저토의 함량이 적은 경향이 있다. 2. Br의 함량은 Tr-290ppm(평균 138.2ppm)이고, 연안 해저토의 함량이 적고, 심해 해저토의 함량이 크다. 3. Ni의 함량은 31-141ppm(평균 89.1ppm)이고, 남부의 대륙붕 해저토의 함량이 적고, 심해 해저토의 함량이 크다. 4. Sr의 함량은 118-3,494ppm(평균 448.6ppm)이고, 남부 대륙붕 해저토의 함량이 현저하게 코고, 영일만 이북해역에서는 연안 해저토의 함량이 크나, 심해 해저토의 함량이 적다. 5. Zn의 함량은 27-134ppm(평균 92.5ppm)이고, 대마도 북부해역에 20-47ppm의 저농도지대가 형성되고, 영일만 이북 해역에서는 연안 해저토의 함량이 적고 심해해저토의 함량이 크다. 6. Mn의 함량은 38-1.043ppm(평균 664.2ppm)으로 변동하나 다른 성분과는 달리 해역별 또는 수심에 따른 분포양상의 특성을 찾아볼 수가 없다. 7. Ti의 함량은 0.04-0.42%이고, 남부 대륙붕해역의 연안부와 북부해역에서 함량이 크고, 대마도 북부에는 0.10%이하의 저농도지대가 발달한다. 8. Fe의 함량은 0.57-4.02%이고, Ti과 같은 분포양상을 자아내고 있다. 9. 동해남부의 대륙붕상 해저토와 영일만이북의 해저토 사이에는 지화학적 성분함량에 차이가 있어, 남부 대륙붕 해저토는 고Sr-저Zn, Br; 고Zr-저Br; 저Br-저Zn, Ti, Fe; 저Zn-저Ti, Fe등의 특성이 있다. 10. Zn과 Ti, Fe 및 Ti과 Fe의 함량 사이에는 밀접한 상관관계가 있고, Zn=279.76Ti +1056, Zn=28.73Fe+13.34, Ti=0.095Fe+0.030 (단 Zn은 ppm, Ti 및 Fe는 %)등의 일차관계식이 성립된다. 11. 또 Zn/Ti $10^{3}$, Zn/Fe $10^{3}$ 및 Ti/Fe의 값은 각각 2.07-6.43 (평균 3.27), 2.25-7.76 (평균 3.46) 및 0.04-0.18 (평균 0.11)로 변동한다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2006년 추계학술발표대회 개요집
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• pp.89-91
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• 2006

An analysis of a multi-pin remote welding for a DUPIC fuel fabrication was made to establish the optimum welding processes in a hot cell environment. An initial investigation for hands-on fabrication outside the hot cell was performed, and the constraints of a hot cell welding were considered. Preliminary welding performances to improve the RW process were also examined. The RW process was determined to be the best in a hot cell environment for joining the end plate to the end caps. This paper presents an outline of the developed RW machine for a DUPIC fuel fabrication and compares the characteristics of a Zr-4 end plate welding by using electrical resistance and LB methods. The weld nuggets of RW specimens and torque strengths of resistant and LB welded zones were also investigated.

• 한국세라믹학회지
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• 제48권2호
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• pp.195-199
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• 2011

The effect of copper oxide on migration and interaction of protons in barium zirconate was investigated using density functional theory. One copper atom was substituted for a zirconium atom site, and a proton was added to a $3{\times}3{\times}3$ barium zirconate superstructure. An energy barrier of 0.89 eV for proton migration was the highest among several energy barriers. To investigate the interaction between multiple protons and a copper atom, two protons were added to the superstructure. Various proton positions were determined by the interaction between the two protons and the copper atom.

• Journal of Magnetics
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• 제18권2호
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• pp.86-89
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• 2013

This paper shows a new effective approach to measure crystallization temperature of soft magnetic underlayer (SUL) for next generation of heat assisted perpendicular recording media. This approach uses temperature dependent reflectivity, which shows a clear jump when samples are crystallized. To achieve this measurement, an optical system is set up using hot plate and infrared laser. Reflectivity of SUL $(Co_{70}Fe_{30})_{92}Ta_3Zr_5$ shows a clear jump at its amorphous-crystalline transition temperature. Experiment results show this effect is clear in infrared region, and is weak for visible light.