• Journal of the Korean Ceramic Society
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• v.40 no.2
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• pp.191-197
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• 2003

Sr ferrites with various compositions were applied to the decomposition of $CO_2$ to mitigate the greenhouse effect. In the reduction reaction of Sr ferrites up to 80$0^{\circ}C$, starting temperature was lower with increasing of Sr content in Sr ferrite. However, the reactivity was higher with decreasing Sr content. In the $CO_2$ decomposition reaction with reduced Sr ferrites, the amount of CO and C were depended on the ratio of Sr and Fe in Sr ferrite. With increasing Sr content. larger amount of C were deposited on the surface of ferrite. Therefore, in order to apply Sr ferrites for the decomposition of $CO_2$, it is necessary to control the ratio of Sr and Fe according to the conditions used.

• Analytical Science and Technology
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• v.33 no.6
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• pp.274-284
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• 2020

This study described the analytical method for simultaneous determination of 89Sr and 90Sr in liquid sample using automated separation system. Radiostrontium in 0.5 kg of liquid sample was concentrated as SrCO3 to reduce the volume of sample, and purified from the sample using Sr-resin 2 mL (BV, Bed volume). The behavior of Sr and interferences such as Ba, Ca and Y were estimated with various flow rate ranging from 1 to 4 mL min-1. The detailed procedure for the purification of Sr on Sr-resin was presented. The purified radiostronitum was measured in Cerenkov mode and then measured in Scintillation mode by mixing scintillation cocktail. The measured value in both modes were used to calculate the activity of 89Sr and 90Sr. The performance tests were carried out the lab-control-sample having various activity ratio of between 89Sr and 90Sr. The recovery of Sr was ranged from 68 to 94 %. The relative bias of 89Sr activity was ranged from -5 to 20 %, and it was ranged from -10 to 10 % for 90Sr.

• Journal of Advanced Navigation Technology
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• v.10 no.1
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• pp.70-78
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• 2006

This paper has addressed the scheme to design single rate Rate Adaptive Shaper (srRAS) proposed in RFC2963. srRAS is the shaper used in conjugation with downstream single rate Three Color Marker (srTCM) described in RFC269. it is tail-drop First Input First Out (FIFO) queue that is drained at a variable rate. srTCM meters IP packet streams from srRAS and marks its packets to be either green, yellow, or red. This shaper has been proposed to use at the ingress of differentiated services networks providing AF PHB. And then srRAS can reduce the burstiness of the upstream traffic of srTCM. This paper addresses algorithm, architecture of srRAS, and the scheme to implement srRAS using Field-Programmable Gate Arrays (FPGA) and the related technology.

• Economic and Environmental Geology
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• v.43 no.3
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• pp.211-222
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• 2010

A batch experiment was carried out to investigate a variation of Sr concentration and $^{87}Sr/^{86}Sr$ ratio in the solution by water-rock interaction. The experiments were conducted at room temperature using two kinds of granites (biotite granite and garnet-bearing granite), de-ionized water. surface water. Water/rock ratio was 1:1. For comparison, we also performed another experiment under water/rock condition of 10:1. Then, the concentration of the cations and anions in the solutions showed severe variation during water/rock interaction. However, after sometime, the $^{87}Sr/^{86}Sr$ ratio of the solution moved to the $^{87}Sr/^{86}Sr$ ratio of the rocks and showed relatively constant value. This suggests that the $^{87}Sr/^{86}Sr$ ratio between water and rock becomes to be stable faster than the elemental equilibration of the element in the solution, and is not affected by interaction condition. Therefore, $^{87}Sr/^{86}Sr$ ratio of the groundwater may be useful in calculating the mixing ratio between different aquifer.

• Journal of the Korean Society for Library and Information Science
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• v.54 no.2
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• pp.179-195
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• 2020

This study searched for the status of medical Systematic Review(SR) publications in Korea and elsewhere for last 10 years, closely analyzing SR research papers by co-authors of Korean librarians. Through interviews with Korean librarians participating in SR, the activities, roles, and difficulties of these librarians were identified, and the results of the interviews helped explore new ways to promote collaboration in SR research. The result of the studied showed that the number of domestic and foreign SR studies has recently increased, and the number of cases where Korean librarians participated in SR research being officially credited as a co-author or acknowledgment source was also grow. The SR librarians in the Korean medical libraries were not only search experts, data collectors, and reference writers, but also did various activities such as designing search strategies, SR search records with complete reproducibility, and DB search tutorship. To promote SR support librarians participated in the interview suggested recruiting new librarians, retraining current librarians, and reformation courses in library and information science. As it is expected that the level of information demand of users and expectations for librarians would also increase in near future, SR librarians' activities and contributions seem to offer a guideline for academic library services that the others should pursue.

• Journal of the Korean Ceramic Society
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• v.37 no.10
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• pp.1008-1013
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• 2000

SrTi $O_3$(001) 단결정 기판 위에 졸-겔 스핀코팅으로 $SrBi_2(Ta,Nb)_2O_9$ 박막을 도포하고 그 결정화 과정을 고온 X-선 회절분석 (HTXRD)으로 추적하면서 Pt(111)/Ti/ $SiO_2$/Si 위에 성장한 박막과 비교하였다. SrTi $O_3$(001) 단결정 기판 위에 도포된 $SrBi_2Nb_2O_{9}$ 박막은 fluorite-like phase와 같은 transient phase를 거치지 않고 곧바로 순수한 $SrBi_2Nb_2O_9$ 상으로 결정화가 시작되었으며 결정화가 시작되는 온도인 ${\sim}540^{\circ}C$부터 c축 배향성장하였다. 또한 $SrB i_2(Ta,Nb)_2O_9$ 박막은 Ta/Nb 비에 관계없이 $SrTiO_3$(001) 위에서 모두 $(00{\ell})$로 배향되었으며, 코팅 횟수가 늘어나 필름의 두께가 증가함에 따라 c축 배향성은 미세한 감소를 보였다. $SrBi_2Nb_2O_9/SrTiO_3$단면을 TEM으로 관찰한 결과 $SrBi_2Nb_2O_9$은 대체로 불규칙한 크기의 다결정체로 되어 있었으나 계면 부근에서는 [001]$_{SBN}$//[001]$_{SrTi}$ $O_3$/, [100]$_{SBN}$//[100]$_{SrTi}$ $O_3$/라는 결정학적 관계를 가지며 에피탁샬 성장했음을 알 수 있었다.있었다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.1
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• pp.49-58
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• 2018

For the immobilization of high-radioactive nuclides such as Cs and Sr by high-temperature thermal decomposition, this study was carried out to investigate the phase transformation with calcined temperature by using TGA (thermogravimetric analysis) and XRD (X-ray diffraction) in the Cs-adsorbed CHA (chabazite zeolite of K type)-Cs and CHA-PCFC (potassium cobalt ferrocyanide)-Cs zeolite system, and Sr-adsorbed 4A-Sr and BaA-Sr zeolite system, respectively. In the case of CHA-Cs zeolite system, the structure of CHA-Cs remained at up to $900^{\circ}C$ and recrystallized to pollucite ($CsAlSi_2O_6$) at $1,100^{\circ}C$ after undergoing amorphous phase at $1,000^{\circ}C$. However, the CHA-CFC-Cs zeolite system retained the CHA-PCFC-Cs structure up to $700^{\circ}C$, but its structure collapsed in $900{\sim}1,000^{\circ}C$, and then transformed to amorphous phase, and recrystallized to pollucite at $1,100^{\circ}C$. In the case of 4A-Sr zeolite system, on the other hand, the structure of 4A-Sr maintained up to $700^{\circ}C$ and its phase transformed to amorphous at $800^{\circ}C$, and recrystallized to Sr-feldspar ($SrAl_2Si_2O_8$, hexagonal) at $900^{\circ}C$ and to $SrAl_2Si_2O_8$ (triclinic) at $1,100^{\circ}C$. However, the BaA-Sr zeolite system structure began to break down at below $500^{\circ}C$, and then transformed to amorphous phase in $500{\sim}900^{\circ}C$ and recrystallized to Ba/Sr-feldspar (coexistence of $Ba_{0.9}Sr_{0.1}Al_2Si_2O_8$ and $Ba_{0.5}Sr_{0.5}Al_2Si_2O_8$) at $1,100^{\circ}C$. All of the above zeolite systems recrystallized to mineral phase through the dehydration/(decomposition) ${\rightarrow}$ amorphous ${\rightarrow}$ recrystallization with increasing temperature. Although further study of the volatility and leachability of Cs and Sr in the high-temperature thermal decomposition process is required, Cs and Sr adsorbed in each zeolite system are mineralized as pollucite, Sr-feldspar and Ba/Sr-feldspar. Therefore, Cs and Sr seen to be able to completely immobilize in the calcining wasteform/(solidified wasteform).

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.2
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• pp.101-112
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• 2016

This study investigated the removal of Sr, which was one of the high radioactive nuclides, by adsorption with Barium (Ba) impregnated 4A zeolite (BaA) from high-radioactive seawater waste (HSW). Adsorption of Sr by BaA (BaA-Sr), in the impregnated Ba concentration of above 20.2wt%, was decreased by increasing the impregnated Ba concentration, and the impregnated Ba concentration was suitable at 20.2wt%. The BaA-Sr adsorption was added to the co-precipitation of Sr with $BaSO_4$ precipitation in the adsorption of Sr by 4A (4A-Sr) within BaA. Thus, it was possible to remove Sr more than 99% at m/V (adsorbent weight/solution volume)=5 g/L for BaA and m/V >20 g/L for 4A, respectively, in the Sr concentration of less than 0.2 mg/L (actual concentration level of Sr in HSW). It shows that BaA-Sr adsorption is better than 4A-Sr adsorption in for the removal capacity of Sr per unit gram of adsorbent, and the reduction of the secondary solid waste generation (spent adsorbent etc.). Also, BaA-Sr adsorption was more excellent removal capacity of Sr in the seawater waste than distilled water. Therefore, it seems to be effective for the direct removal of Sr from HSW. On the other hand, the adsorption of Cs by BaA (BaA-Cs) was mainly performed by 4A within BaA. Accordingly, it seems to be little effect of impregnated Ba into BaA. Meanwhile, BaA-Sr adsorption kinetics could be expressed the pseudo-second order rate equation. By increasing the initial Sr concentrations and the ratios of V/m, the adsorption rate constants ($k_2$) were decreased, but the equilibrium adsorption capacities ($q_e$) were increasing. However, with increasing the temperature of solution, $k_2$ was conversely increased, and $q_e$ was decreased. The activation energy of BaA-Sr adsorption was 38 kJ/mol. Thus, the chemical adsorption seems to be dominant rather than physical adsorption, although it is not a chemisorption with strong bonding form.

• Journal of the Korean Ceramic Society
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• v.23 no.6
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• pp.45-51
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• 1986

$SrTiO_3$ reaction mechanism formed from $TiCl_4$ and $SrCl_2$ solution by direct-wet-process was studied. Through this study it is identified that crystalline $SrTiO_3$ is formed above pH 13.8 amorphous $SrTiO_3$ above pH7 and crystallization temperature of amorphous $SrTiO_3$ is at 37$0^{\circ}C$. the final products are composed of 60% crystalline $SrTiO_3$ and 40% amorphous $SrTiO_3$ The amorphous $SrTiO_3$ is identified with the IR absorption spectrum of Sr-Ti-O by FT-IR spectrometer. Under pH 7 gelationus metatitanate (H2TiO3) is formed from TiCl4 but above pH7 the activity by the formation of metatitnic acid ion $[TiO_3]^{2-}$ is so high that $SrTiO_3$is formed more easily through the reaction with $Sr^{2+}$.

• Journal of Radiation Protection and Research
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• v.16 no.1
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• pp.33-42
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• 1991

A pot experiment on the Sr-90 uptake by the barley from a loamy-sandy soil of pH 6.05 treated with Sr-90 and slaked lime was carried out in a green house. The rate of Sr-90 uptake at maturity was, on an average, 0.41% for a naked barley Neolssalbori and 0.23% for a covered one Olbori. Transfer coefficients of Sr-90 for the former were higher than those for the latter by about 30-60% depending on the plant parts. There were, on the whole, not significant differences in the rate and in the coefficient among Sr-90 concentration treatments. Slaked lime addition equivalent to about 94kg/10a was not effective for lessening Sr-90 uptake or diminishing Sr-90 transfer coefficient. As transfer coefficients, 1.51, 4.45, 0.35, and 1.30, on the dry weight basis, could be proposed for the stem, leaf, seed, and whole top of the barley, respectively. Growth inhibition or yield decrease due to Sr-90 uptake was not observed.