• 분석과학
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• 제8권4호
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• pp.623-630
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• 1995

Silicone rubber-based sodium-selective membranes are developed for solid-state ion sensors. It was shown that the potetiometric performance of SR-based membranes are greatly dependent on the type of neutral carriers employed; among the three ionophores, N,N,N',N'-tetracyclohexyl-1,2-phenylenedioxydiacetamide (ETH 2120), bis[(12-crown-4)methyl]dodecylmethylmalonate (D12C4DMM) and monensin methyl ester (MME), examined, only ETH 2120 was compatible with the SR-based matrix. Addition of about 20 wt% plasticizer to the SR-based matrix provided the resulting membranes with potentiometric properties essentially equivalent to those of the corresponding PVC-based membranes. Owing to the strong adhesive strength of SR-based membranes, the CWEs coated \vith those membranes exhibited long lifetime with conventional electrode-like performance. Blending of PU into the SR matrix increased the lifetime of CWEs from two weeks to one month.

• Journal of Radiation Protection and Research
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• 제11권2호
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• pp.104-113
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• 1986

이온교환시스템, $Cs^{+1},\;Sr^{+2},\;Th^{+4},\;and\;7Cl^{-}-H^{+}$ Dowex HCR-W2, 에서 $Cs^{+1},\;Sr^{+2}$, 이온들이 이온수지 Dowex HCR-W2에 흡착분리될 때의 이온교환 거동에 대하여 연구했다. $Th^{+4}$이온은 느린 속도의 흡착을 보여 주는 반면에 $Cs^{+1}$과 $Sr^{+2}$이온은 대체로 빠른 속도로 흡착되었다. $Th^{+4}$이온의 강한 흡착력 때문에 수지와 용액의 접촉시간이 길면 이미 흡착된 $Cs^{+1}$과 $Sr^{+2}$이온은 다시 수지로 부터 분리되어 용액쪽으로 나오기 때문에 소량의 $Cs^{+1}$과 $Sr^{+2}$이온이 용액으로부터 회수 또는 제거되었다. 용액 전체 노르말이 0.1 N 이고 $Cs^{+1}:\;Sr^{+2}:\;Th^{+4}$의 각각의 노르말비가 2 : 2 : 1의 용액인 경우 $Cs^{+1}$이 최대로 흡착되는 접촉시간은 4분정도이며, $Sr^{+2}$이온의 흡착정도는 20분정도에서 최대가되었다. 흡착된 이온을 수지로부터 분리하는데 HCl 용액을 사용했으며 $Cs^{+1}$ 이온은 0.1 N 이하의 농도에서 분리가 잘 되었고 ($Sr^{+2}$의 오염이 5%이하였다.) $Th^{+4}$이온은 1 N 이상의 농도에서 분리가 되는데, 가장 효과적으로 분리되는 HCl의 농도는 4N 이었다.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2000년도 High Temperature Superconductivity Vol.X
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• pp.165-168
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• 2000

We fabricated ramp-edge Josephson junctions with barriers formed by interface treatments instead of epitaxially grown barrier layers. A low-dielectric Sr$_2$AlTaO$_6$(SAT) layer was used as an ion-milling mask as well as an insulating layer for the ramp-edge junctions. An ion-milled YBa$_2$Cu$_3$O$_{7-x}$ (YBCO)-edge surface was not exposed to solvent through all fabrication procedures. The barriers were produced by structural modification at the edge of the YBCO base electrode using high energy ion-beam treatment prior to deposition of the YBCO counter electrode. We investigated the effects of high energy ion-beam treatment, annealing, and counter electrode deposition temperature on the characteristics of the interface-controlled Josephson junctions. The junction parameters such as T$_c$, I$_c$c, R$_n$ were measured and discussed in relation to the barrier layer depending on the process parameters.

• 한국환경과학회지
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• 제9권6호
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• pp.517-522
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• 2000

Separation of strontium ion from synthetic seawater in the contained liquid membrane permeator with two micro-porous films was performed. The permeator consisted of a liquid membrane and two cells for aqueous solutions. The liquid membrane consisted of $D_2EHPA(di-2-ethylhexy1-phosphoric acid)$ and DCH18C6 (dicyclohexano-18-crown-6),diluted to 30 vol% with kerosine and was trapped between two micro-porous hydrophilic films. This liquid membrane separated two aqueous solutions, one of which was synthetic seawater and the other of which was the stripping solutions consisting of 1mol/L $H_2SO_4$ solution. The effects of various operating parameters on the extraction rate and equilibrium extraction ratio of strontium ion from synthetic seawater were experimentally examined. The addition of DCH18C6 to the $D_2EHPA$ solution caused synergy effect on the extraction of strontium ion. The permeator extracted strontium ion from synthetic seawater effectively with high membrane life time.

• 분석과학
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• 제14권1호
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• pp.8-14
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• 2001

환경 시료인 토양, 우유, 해수, 해조류, 어패류, 솔잎 및 해저토 중에 존재하는 $^{90}Sr$의 농도를 결정하기 위한 새로운 형태의 분리농축법을 확립한 후 ICP-AES를 사용하여 각 분석과정을 검토하였다. 처리 과정을 단축시킨 발연 질산법 및 이온교환수지법을 혼합한 새로운 형태의 분석과정으로 $^{90}Sr$의 농도를 정량한 결과 효과적으로 Ca를 완전히 제거할 수 있었으며, 발연질산법 만을 사용했을 경우보다 스트론튬의 회수율이 약 10% 이상 높게 나타났다. 이 방법은 토양, 우유, 해조류, 어패류, 솔잎, 및 해저토 등 환경 시료들 중의 $^{90}Sr$ 결정에 적용할 수 있음을 확인하였다. 분석 결과, 토양 중의 $^{90}Sr$ 농도가 가장 높았으며 모든 시료 중의 $^{90}Sr$의 농도는 환경 기준치 이하로 나타났다.

• 한국세라믹학회지
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• 제23권6호
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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 $Sr^{2+}$.

• 한국결정학회지
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• 제13권1호
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• pp.25-30
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• 2002

M/sub 1-x/Na/sub 2x/Al₂(BO₃)₂O (M = Ca and Sr) 고용체계는 치환형과 틈새형 고용체를 동시에 갖는다. 이상의 고용체계 물질에 첨가된 발광원자의 에너지 전이는 발광원자, Eu 주위의 대칭성에 깊은 관계가 있다 Eu/sup 3+/ 이온의 경우, Eu/sup 3+/ 이온의 주변 대청성에 따라서 매우 밝고 효율적인 발광성 불순물이 될 수 있기 때문에 구조와 연계한 연구가 가능하다. Eu/sup 3+/: Ca/sub 1-x/Na/sub 2x/Al₂(BO₃)₂O 고용체계의 Na원자 양이 증가함에 따라 Eu3+ 이온의 대칭성이 낮아진다. CaAl₂(BO₃)₂O 화합물은 Ca 원자 중심의 팔면체 구조를 갖기 때문에, 조성비 x의 증가와 함께, 화합물의 낮은 대청성에 의해서 Eu/sup 3+/:Ca/sub 1-x/Na/sub 2x/Al₂(BO₃)₂O 고용체계의 /sup 5/D/sub 0/→/sup 7/F₁(590 nm) 전이의 상대적인 세기가 감소한다. 그러한 또 다른 예는 비대칭성 물질인 Eu/sup 3+/:SrAl₂(BO₃)₂O 화합물에서도 찾아 볼 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 제5회 학술대회 논문집 일렉트렛트 및 응용기술연구회
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• pp.49-52
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• 2003

BiSrCaCuO superconducting thin films have been fabricated by co-deposition using IBS(Ion Beam Sputtering) method. Despite setting the composition of thin film Bi2212 or Bi2223, in both cased, Bi2201, Bi2212 and Bi2223 phase were appeared. It was confirmed the obtained field of stabilizing phase was represented in the diagonal direction of the right below end in the Arrhenius plot of temperature of the substrate and $PO_3$ and it was distributed in the reeone.

• 한국전기전자재료학회논문지
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• 제13권3호
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• pp.183-187
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• 2000

In this study the SrBi$_2$Ta$_2$$O_{9}$ (SBT) thin films were etched by using magnetically enhanced inductively coupled Ar/CHF$_3$plasma as function of CHF$_3$/(Ar+CHF$_3$)gas mixing ratio. Maximum etch rate of SBT thin films was 1650 $\AA$/min and the selectivities of SBT to Pt and photoresist(PR) were 1.35 and 0.94 respectively under CHF$_3$/(Ar+CHF$_3$) of 0.1 For study on etching mechanism of SBT thin film X-ray photoelectron spectroscopy (XPS) surface analyses and secondary ion mass spectrometry (SIMS) mass analysis of etched SBT surfaces were performed. Among the elements of SBT thin film. M(Sr, Bi, Ta)-O bonds are broken by Ar ion bombardment and form SrF and TaF$_2$by chemical reaction with F. SrF and TaF$_2$are removed more easily by Ar ion bombardment. Scanning electron microscopy(SEM) was used for the profile examination of etched SBT film and the cross-sectional SEM profile of etched SBT film under CHF$_3$(Ar+CHF$_3$) of 0.1 was about 85$^{\circ}$X>.

• 한국전기전자재료학회논문지
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• 제15권11호
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• pp.933-938
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• 2002

(Ba,Sr)TiO$_{4}$ (BST) thin films on Pt/Ti/SiO$_{2}$/Si substrates were deposited by a sol-gel method and the etch characteristics of BST thin films have been investigated as a function of gas mixing ratio. The maximum etch rate of the BST films was 440 $AA$/min under such conditions as: CF$_{4}$(CF$_{4}$＋Ar) of 0.2, RF-power of 700 W, DC-bias voltage of -200 V, pressure of 15 mTorr and substrate temperature of 30 $^{circ}C$. The selectivities of BST to Pt, SiO$_{2}$ and PR were 0.38, 0.25 and 0.09, respectively. In the XPS (X-ray photoelectron spectroscopy) analysis, Barium (Ba) and Strontium (Sr) component in BST thin films formed low volatile compounds such as BaFx, SrFx, which are forms by the chemical reaction with F atoms and is removed by Ar ion bombardment. Titanium (Ti) is removed by chemical reaction such as TiF with ease. The result of secondary ion mass spectrometry (SIMS) analysis confirmed the existence of the BaFx, SrFK, TiFx.