• 분석과학
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• 제17권1호
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• pp.23-28
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• 2004

Trace amount of uranyl (II) has been determined spectrophotometrically by measuring the optical density of the light blue yellowish coloured solutions formed by reaction between the metal ion and nicotinohydroxamic acid (NHx) in presence of different secondary ligands in strong isoamyl alcohol alkaline medium. The absorption maxima for both aqueous and extracted systems measured at their respective optimum pH were found to be 360 and 559 nm (DETA), 375 and 358 nm (EDA), 369 and 362 nm (piperidine), 354 and 341 nm (pyridine) and 363 and 336 nm (3 piperidine), 354 and 341 nm (pyridine) and 363 and 336 nm (3 - picoline), respectively at which Beer's law was obeyed. Effect of pH, reagent concentration, order of addition of reagent, time, temperature and solvent media on the absorption spectra have also been studied. Among the different systems studied, the shortest concentration range of uranyl(II) adhering to Beer's Law was 2.4 - 10.5 ppm observed for $UO_2(II)$ - NHx - DETA system in aqueous medium and also for iso amyl alcohol(IAA) extracted $UO_2$ - NHx - pyridine system was 2.4 - 7.8.

• 대한화학회지
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• 제24권3호
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• pp.245-249
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• 1980

도데칸에 녹인 아세틸아세톤과 트리부틸인산으로 묽은 질산우라닐수용액에서 우라늄(Ⅵ)을 추출했다. pH 1 이상에서 이 혼합추출제의 상승적 효과가 관측되었다. 추출되는 화학종은 1:2:1 및 1:2:2 우라닐-아세틸 아세톤-트리부틸 인산착물이다. 이들 반응의 추출정수들을 측정하였다.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.689-695
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• 2003

Electrochemical decontamination process has been applied for recycle or self disposal with authorization of large amount of metallic wastes contaminated with uranium compounds such as $UO_2$, ammonium uranyl carbonate (AUC), ammonium di-uranate (ADU), and uranyl nitrate(UN) with tributylphosphate(TBP) and dodecane, which are generated by dismantling the contaminated system components and equipment of a retired uranium conversion plant in Korea Atomic Energy Research Institute (KAERI). Electrochemical decontamination for metallic wastes contaminated with uranium compounds was evaluated through the experiments on the electrolytic dissolution of stainless steel as the material of the system components in neutral salt electrolytes. The effects of type of neutral salt as the electrolyte, current density, and concentration of electrolyte on the dissolution of the materials were evaluated. Decontamination performance tests using the specimens taken from a uranium conversion plant were quite successful with the application electrochemical decontamination conditions obtained through the basic studies on the electrolytic dissolution of structural material of the system components.

• 대한화학회지
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• 제6권1호
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• pp.1-9
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• 1962

高純度의 $UO^2$ pellets나 或은 $UF_4$를 얻는 것을 目標로 하여 그 計劃의 一郡으로 純粹한 $UO_2^{++}$ 溶液을 $U^{+4}$溶液으로 電解還元하는 方法을 實驗하였다. 現在 實施되고 있는 方法으로서는 純粹한 $UO_3$粉末을 水素 或은 ADU(ammonium diuranate)를 熱分解하여 生成되는 分解된 암모니아로서 600 내지 900$^{\circ}C$ 還元하거나 혹은 복잡한 構造를 가진 Excer cell로서 濕式電解하는 方法들이 있다. 이 報告는 從來의 Excer cell을 改造하여 水銀陰極과 陽이온 交換樹脂의 膈膜 및 鉛陽極으로 구성되는 간단한 電解裝置로서 $UO_2^{++}$ 溶液을 連續的으로 電解시켰을 때 가장 適合한 電解槽의 構造, 電解液의 溫度, 電解液의 種類와 濃度 또 各 流量과 電流密度에 따르는 電流效率, 電解槽電壓等을 測定한 結果를 記錄하고 電解反應을 說明한 것이다. 實驗結果에 依하면 電解槽는 水平式으로 하여 길이와 폭의 比가 20對 1이고 電解液은 還元에 所要될 때 理論量 以上의 遊離黃酸이 共存하는 可及的 高農度의 $UO_2SO_4$ 溶液과 그에 比例하는 電流密度를 使用하여 電解함으로써 單一過程의 電解에 依하여 $UO_2^{++}$ 를 $U^{+4}$로 80 내지 95%의 電流效率로서 還元시킬 수 있다는 것을 알았다.

• Nuclear Engineering and Technology
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• 제13권4호
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• pp.254-263
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• 1981

특별히 제작한 영동장치를 써서 여과지 전기영동법에 의한 핵분열 생성물의 분리를 하였다. 일반적으로 루비듐, 스트론늄, 지르코늄, 루테늄, 세슘, 세륨, 모리브덴 그리고 몇가지 단수명 핵분열 생성물의 분리는 0.1몰 가성소오다 전해질보다 0.1몰 염산 전해질 경추 더욱 효과적이다. 넵투늄-239에 더하여 특히 요오드 131∼135등이 단시간 중성자 조사한 질산 우라닐 용액의 여과지 전기영동법 분리에서 얻은 요오드 화학종 들에서 관찰되었다.

• Journal of Pharmaceutical Investigation
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• 제17권4호
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• pp.205-211
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• 1987

Renal dysfunction can have pronounced effects on the pharmacokinetic and pharmacodynamic characteristics of drugs. Because the exploration of these effects in patients may be limited by ethical and practical considerations, it often become necessary to perform studies on animals with experimental renal failure(ERF). ERF was produced in rats by the administration of uranyl nitrate, glycerol, salicylate, gentamicin and folate in this study. Changes in glomerular filtration rate(GFR) and renal secretion clearance of tetraethylammonium bromide$(CL^{scn}_{TEA})$, together with morphological changes of kidney cortex were evaluated and compared among ERF models. GFR(or glomeruli) and $CL^{scn}_{TEA}$(or renal tubules) were not damaged parallelly in some ERF model rats. Therefore, it seemed to be necessary to adjust dosage regimen of some basic drugs like TEA in renal dysfunction considering the functional changes of renal secretion in addition to glomerular filtration.

• 한국세라믹학회지
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• 제42권9호
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• pp.618-623
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• 2005

HTGR (High Temperature Gas-Cooled Reactor) is highlighted to next generation power plant for producing the clean hydrogen gas. In this study, the spherical $UO_2$ kernel via $UO_3$ gel particles was prepared by the sol-gel process. Raw material of slightly Acid Deficient Uranyl Nitrate (ADUN) solution, which has pH = 1.10 and $[NO_3]/[U]$ mole ratio = 1.93, was obtained from dissolution of $U_3O_8$ powder with conc.-$HNO_3$. The surface of these spherical $UO_3$ gel particles, which was prepared from the broth solution, consisted of 1 M-uranium, 1 M-HMTA, and urea, were covered with the fine crystallite aggregates, and these particles were so hard that crushed well. But the other $UO_3$ gel particles prepared with the broth solution, consisted of 2 M-uranium, 2 M-HMTA, and urea, have soft surface characteristics and an amorphous phase. This type of $UO_3$ gel particles is some chance of doing possibility of high density from the compaction. The amorphous $UO_3$ gel particles was converted to $U_3O_8$ and then $UO_2$ by calcination at $600^{\circ}C\;in\;4\%\;-\;H_2\;+\;N2$ atmosphere.

• 한국세라믹학회지
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• 제44권2호
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• pp.124-131
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• 2007

In this study, first the ADU gel particle, an intermediate for final $UO_2$ kernel of a HTGR nuclear fuel, was prepared from sol-gel method using the broth solution which was made by mixing of the uranyl nitrate, poly vinyl alcohol and tetra-hydrofurfuryl alcohol. The prepared dried-ADU gel particles were converted to the $UO_2\;via\;UO_3$ from thermal treatment with the 4% $H_2$ atmosphere. The sizes of the spherical liquid droplets appeared $1900{\sim}2100{\mu}m$, and the harmony between the flow rate of the broth solution and the frequency and the amplitude of a vibrating system are important factors for the spherical ADU gel particles via the mono size spherical droplets. From the XRD and FT-IR analyses, the prepared ADU gel particles were judged to be a $UO_3{\cdot}xNH_3{\cdot}yH_2O$ form, and the most important factor during the thermal treatment of the dried-ADU gel particle must be avoided a rapidly heating rate in the range of $180{\sim}400^{\circ}C$, and the heating rate should be kept below $5^{\circ}C/min$.

• 한국세라믹학회지
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• 제44권8호
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• pp.437-444
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• 2007

The broth solution was prepared by the mixing of an uranyl nitrate, THFA, PVA, and water. The uranium concentration of the broth solution was $0.5{\sim}0.8$ mole-U/L and the viscosity of it was $30{\sim}80cSt$. The droplets of this broth solution were farmed in air and ammonia by the vibrating nozzle with the frequency of 100 Hz at the amplitude of $100{\sim}130V$. The diameter of the droplet was about $1900{\mu}m$ from using the nozzle diameter of 1 mm. The diameter of the aged gel was about $1400{\mu}m$ after aging in ammonia solution at $60{\sim}80^{\circ}C$, and the dried gel with the diameter of about $900{\mu}m$ was obtained after drying at room temperature or partially vacuum condition. The diameter of the calcined $UO_3$ microsphere after calcination at $600^{\circ}C$ appeared about $800{\mu}m$ in air atmosphere. Although the droplets of the same sizes were formed, the calcined microspheres of different sizes were manufactured in the case of the broth solutions of the different uranium concentration. The droplets of the desired diameters were obtained by the change of the nozzle diameters and the broth flow rates.

• 한국세라믹학회지
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• 제42권11호
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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 $600^{\circ}C$.