• Journal of the Mineralogical Society of Korea
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• v.15 no.1
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• pp.78-84
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• 2002

New pyrochlore-type phases($A_2$$B_2$$O_{7}$) were synthesized in the systems: CaO-C$eO_2$-T$iO_2$, CaO-$UO_2$(T$hO_2$)-Z$rO_2$, CaO-$UO_2$(T$hO_2$)-$Gd_2$$O_3$-T$iO_2$-Z$rO_2$, 및 CaO-T$hO_2$-S$nO_2$. The starting materials were pressed with the pressure of 200~400 MPa and sintered at 1500~ 155$0^{\circ}C$ for 4~8 hours in air and at 1300~ 135$0^{\circ}C$ for 5 ~50 hours under oxygen atmosphere. The products were characterized using XRD, SEM/EDS and TEM. In the bulk compositions of CaCe$Ti_2$$O_{7}$, CaTh$Zr_2$$O_{7}$,($Ca_{0.5}$ Gd$Th_{0.5}$)(ZrTi)$O_{7}$) ($Ca_{0.5}$Gd$Th_{0.5}$)(ZrTi)$O_{7}$, ($Ca_{0.5}$G$dU_{0.5}$)(ZrTi)$O_{7}$ and CaTh$Sn_2$$O_{7}$ , pyrochlore was the major phase, together with other oxide phase $of_2$$O_{7}$ fluorite structure. In the samples with target compositions CaU$Zr_2$$O_2$및 $Ca_{0.5}$ G$dU_{0.5}$)$Zr_2$T$iO_{7}$ pyrochlore was not identified, but a fluorite-structured phase was detected. The formation factor as the stable phase depended on crystal chemical characteristics of the actinide and lanthanide elements of the system concerned.

• Journal of the Korean Ceramic Society
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• v.42 no.11 s.282
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• pp.729-736
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• 2005

HTGR (High Temperature Gas-cooled Reactor) is spotlighted to next generation nuclear power plant for producing the clean hydrogen gas and the electricity. In this study, the spherical $UO_3$ gel particles were prepared by the external gelation process, and the characteristics of these particles were analyzed the particle shape, composition of precipitate, and thermal decomposition characteristics with the Streoscope, FT-IR, and X-ray diffractometer. Raw material of the ADUN (Acid Deficient Uranyl Nitrate) solution, which has [$NO_3$]/[U] mole ratio = 1.75, was obtained from dissolution of the $U_{3}O_{8}$ powder with concentrated $HNO_3$, and its concentration is 3.5 M-U/l. The broth solution is prepared with the ADUN, urea, PVA, and THFA solution. The droplets of the broth solution was made through a nozzle system. From this study, we obtained the following results; 1) an externel chemical gelation process is a suitable method in the spherical $UO_3$ particle production, 2) the particle shape are changed by an urea mixing time, THFA volume, and the viscosity of the broth solution, 3) the amorphous $UO_3$ particles obtained from these experiments was converted to $U_{3}O_{8}$ and then $UO_2$ by heat treatment in hydrogen atmosphere at $600^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.173-173
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• 2009

높은 휘도를 갖는 $Eu^{2+}$가 도핑된 $Sr_3MgSi_2O_8$ 형광체는 고상반응법을 사용하여 합성하였다. 몰 비에 따른 조성을 정밀전자저울을 사용 무게를 칭량하여 에탄올을 용매로 하여 혼합, 건조 후 하소 온도는 $1000^{\circ}C$, 합성 온도는 $1200^{\circ}C$에서 $1400^{\circ}C$까지 $H_2$ 5% Ar 95% 환원분위기에서 소성 온도 별 결정상을 관찰하였고, 그 형태에 따라서는 Powder상태일 때와 Powder를 Press하여 bulk상태로써의 결정상의 변화를 연구하였다. 그 결과 분말상태와 성형을 가한 pellet의 두 가지 형태로 합성하여 비교한 결과 성형공정을 거친 시료의 경우가 분말 상태일 때 보다 좋지 못한 결정상이 관찰되었다. $Sr_3MgSi_2O_8$의 미세구조는 SEM으로 관찰하였다.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.805-805
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• 1995

핵연료저장시설의 화재 등 극단적인 사고조건하에서 $UO_2$ 소결펠렛의 습식산화와 건식산화에 대한 연구를 수행하였다. 손상된 지르칼로이 피복관 속의 $UO_2$ 소결펠렛을 산성분위기의 습윤조건하에서 산화시킬 때의 $UO_2$ 펠렛의 산화속도는 IDR(mg/$\textrm{cm}^2$.min) = 1.55 [H$^{+}$]$^{1.21}$ 로 나타났다. 또한 습윤조건하에서 $UO_2$ 분말에 알카리 및 알카리 토금속 산화물, 그리고 백금족 및 회토류 산화물 등과 같은 불순물들이 존재할 때의 산화속도를 조사하였으며 이들에 대한 영향도 관찰하였다. 핵연료저장시설의 가상화재를 바탕으로 한 400~$700^{\circ}C$의 온도범위에서, 피복관이 씌워진 $UO_2$ 소결펠렛의 건식산화반응을 조사한 바 $UO_2$ 소결펠렛은 산화초기에 U$_4$O$_{9}$ 또는 U$_3$O$_{7}$ 등의 중간상 형성에 따른 3-4%의 부피축소에 의해 결정립계 균열이 일어나고, $600^{\circ}C$ 이하에서는 온도증가에 따라 중간상에서 U$_3$O$_{8}$ 상으로의 상변화에 의한 부피팽창으로 피복관의 변형과 함께 산화속도의 가속을 발견할 수 있었고, $600^{\circ}C$ 이상에서는 핵연료소자의 소성변형으로 인한 산화속도의 지연을 발견할 수 있었다. 또한 $UO_2$ 펠렛의 건식산화거동은 기체-고체 반응시의 전형적인 형태인 shrinking core model에 잘 적용될 것으로 판단되었다.

• Nuclear industry
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• v.8 no.1 s.59
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• pp.68-76
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• 1988

지금까지 전세계의 원자로 기수와 위치에 대해서는 많은 관심을 갖고 있는 반면 핵연료주기시설에 대해서는 무심하였다. 최근 Nuclear Engineering International지가 예로케이크$(U_3O_8)$형태 이후의 우라늄을 취급하는 시설을 조사하여 '87년 12월호에 게재하였다. 다음은 각국의 핵연료주기 관련 플랜트의 위치, 소유주 및 그 용량 등을 정리한 것이다.

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.11a
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• pp.118-118
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• 1994

Processings of the P $b_2$S $r_2$( $Y_{1-x}$ C $a_{x}$) C $u_3$ $O_{8+{\delta}}$ (2213)system for x=0.4-0.6 to control deleterious oxidative decomposition have been studied. Our results show that comounds are stable at both low p $O_2$ and high p $O_2$ if they are suitably oxidized. Various oxidation and deoxidation procedures have been investigated in order tp determine the optimum hole concentration in the Cu $O_2$layers for the maximum $T_{c}$. In cases x=0.5 and x=0.6, the optimum hole concentration in the 2213-phase is achieved, but with accelerated oxidative decomposition. Destite this, the maximum $T_{c}$~80-83K for the 2213-phase can be deduced when x=0.5 to 0.6 to 0.6

• Journal of the Korean Ceramic Society
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• v.37 no.12
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• pp.1212-1220
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• 2000

Bi-2223 초전도체계에서 석출물을 flux-pinning center로 이용할 수 있는지 가능성을 타진하기 위하여 $Bi_{1.8}$P $b_{0.4}$S $r_{2}$C $a_{2.2}$C $u_3$ $O_{8}$ 조성을 가진 Bi-2223/Ag 선재를 반응온도, 산소분압, 시간 등을 변화시키면서 열처리를 행하였다. 열처리 후 석출물들은 XRD, SEM, TEM, EDS로 분석하였다. Bi-2223 모상내의 (Ca, Sr)$_2$(Pb,Bi) $O_4$, B $i_{0.5}$ P $b_3$S $r_2$C $a_2$Cu $O_{12+}$$\delta$/ (3221)와 같은 2차상들의 크기와 분포는 2223 입자들의 연결성을 파괴하지 않고 열처리 조건에 의해서 조절할 수 있었다. 서냉 열처리가 된 시편은 임계전류밀도( $J_{c}$)값이 증가하였는데, 이는 2223 입자내 나노미터 크기로 형성된 석출물들이 flux-pinning sites로 작용한 것으로 추정된다.다.

• Journal of the Society of Disaster Information
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• v.3 no.1
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• pp.103-116
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• 2007

Der Begriff des Todes $h{\ddot{a}}ngt$ die einzelne Wertvorstellung ab, so dass die Unanschaulichkeit des Todes besteht und noch zu $kl{\ddot{a}}ren$ ist. Im koreanischen Recht, findet sich keine Legaldefinition des Todes. In der juristischen Literatur herrscht der Herztod, nach dem $f{\ddot{u}}r$ den Todeszeitpunkt der irreversible und $vollst{\ddot{a}}ndige$ Stillstand der $Herzt\ddot{a}tigkeit$ gehalten wird, $herk{\ddot{o}}mmlicherweise$ bis jetzt als Todesdefinition vor. Der Herztod basiert darauf, dass Individualtod des Menschen durch den $endg{\ddot{u}}ltigen$, nicht behebbaren Stillstands von Herzschlag nach Ausfall von Atmung eingetreten sind. Auch der medizinische Laie kann den Herztod einfach wahrnehmen und sicher feststellen. Darauf folgt der Herztod als sicheres Todeszeichen angesehen wird. In der Regel trete der Herztod letzte Mal im $nat{\ddot{u}}rlichen$ Sterbeprozess ein. Die $j{\ddot{u}}ngste$ $k{\ddot{u}}nstlichen$ Reanimationsma ${\SS}nahmen$ $erm{\ddot{o}}glicht$ es, die Atmungs- und Kreislauffunktion $f{\ddot{u}}r$ eine begrenzte Zeit $k{\ddot{u}}nstlich$ aufrecht zu erhalten. Die Entwicklung der Medizin machte es zu erkennen, dass das "Zentralorgan Gehirn" $f{\ddot{u}}r$ die Aufrechterhaltung der biologischen Lebensfunktion des Gesamtorganismus unverzichtbar ist. Die Verbesserung von Transplantationstechniken gab $gro{\SS}en$ Anlass neben $f{\ddot{u}}r$ den verbesserten Reanimationstechniken auch $f{\ddot{u}}r$ den Fortschritt auf dem Gebiet der toten Transplantation. Je frischer die Organe sind, desto $gr\ddot{o}{\SS}er$ sind die Chancen $f{\ddot{u}}r$ eine erfolgreiche Verpflanzung und $f{\ddot{u}}r$ $T{\ddot{a}}tigkeit$ im $Empf{\ddot{a}}ngerorganismus$. Die Organentnahme als solche wird $unzul{\ddot{a}}ssig$ nur durch Feststellung des Herztod bei lebenswichtigen Organe, besonders wie Herz. Der Herzstillstand allein ist aber kein sicheres Kriterimn $f{\ddot{u}}r$ die $Zul{\ddot{a}}ssigkeit$ der Organentnahme. Im Korea wurde das Gesetz ${\ddot{u}}ber$ die Transplantation von Organen (Gesetz-Nummer 5858) am 8. Februar 1999 ${\ddot{o}}ffentlich$ bekannt gemacht l1nd trat am 9. Febrllar 2000 in Kraft(${\S}$ 1 Schussvorschriften kTPG). Aus der Sicht des Gesamthirntod definiert das Transplantationsgesetz derjenige, dass nach Kriterien und Nachweisverfahren $f{\ddot{u}}r$ Hirntodfeststellung dieses Gesetzes der irreversible Ausfall der Gesamthirnfunktion festgestellt wird, als Hirntoter (${\S}$ 3 Nr.4 kTPG). Mit dieser Regelung wird die Feststellung des Gesamthimtodes als gesetzliche Mindestvoraussetzung $f{\ddot{u}}r$ die Organentnahme festgelegt. Es handelt sich um Kriterien und Nachweisverfahren $f{\ddot{u}}r$ Hirntodfeststellung des koreanischen Transplantationsgesetzes.

• Korean Journal of Pharmacognosy
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• v.29 no.2
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• pp.75-78
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• 1998

In the course of phytochemical studies for the aerial parts of Ajuga multiflora, one flavonoid and two iridoid glycosides were isolated and identified as apigenin (1), 8-O-acetylharpagide (2) and harpagide (3) on the basis of spectroscopic evidence.

• Parasites, Hosts and Diseases
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• v.31 no.2
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• pp.83-90
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• 1993

We performed bromodeoxyuridine (BrdU) staining to observe the proliferation pattern of epithelial cells on the biliaJy mucosa in Clonorchis sinensis infection. Albino rats were infected with 100 metacercariae each and their livers were processed for histopathological observation after BrdU injection. Five to six sites in the liver of a rat were selected for paraffin section, and stained immunohistochemically to visualize BrdU incorporating cells. The flukes were mainly in the common bile duct and right or left hepatic bile ducts. The proportion of stained epithelial cells in the infected bile ducts where the worms were found on the section was 2.9-10.2% at 1 week after infection. 7.3-12.8% at 2 weeks, 7.3-13.4% at 5 weeks, and 8.4-14.8% at 15 weeks while in the non-infected ducts o to 2.7% cells were stained. The stained cells were mainly at the base of the mucosal layer. It is suggested that mucosal epithelial cells of the bile ducts infected with C. sinensis become hyperplastic mainly by direct and local stimulation of the worms.