The Alkali-Metal Thermal to Electric Converter (AMTEC) can be used as a next-generation power generation technology related with a large thermal energy storage. In particular, this technology is expected for the higher efficiency by a cascade power generation with the thermoelectric generator(TEG), and the temperature distribution becomes a very important design parameter in this case. In this study, the temperature distribution of the AMTEC unit was analyzed through CFD analysis, and design points were discussed based on the results.
알칼리 금속 이온과 염소 이온이 포함된 용액으로부터 이온교환수지를 이용한 이온 제거에 대한 연구를 진행하였다. 양이온인 금속이온(Na+와 K+)의 제거에는 양이온교환수지를, 음이온인 염소 이온(Cl-)의 제거에는 음이온교환수지를 사용하였다. 용액 A (Na+를 36,633 ppm, Cl-를 57,921 ppm 함유)의 경우, Na+ 이온과 Cl- 이온은 20분 이내에 99% 이상 제거되었다. 용액 B (K+를 1,638 ppm 함유)의 경우, K+ 이온은 3분 이내에 99% 이상 제거되었다.
In this study, CO₂ adsorbent was produced for minimizing energy loss due to ventilation within the building. For improved selectivity about low concentration of CO₂ in multiple-use facilities, the ball type adsorbent was modified from a commercial zeolite, alumina, alkali metals and activated carbon with mixing LiOH, binder, and H₂O. We measured specific surface area, pore characteristic, and crystal structure of the modified adsorbent. Effects of alkalization on the absorptive properties of the adsorbents were investigated. Continuous column tests (2,000 ppm) and batch chamber tests (4m3, 5,000ppm) showed that the modified adsorbent indicated about the selectivity of CO₂ more than 9.7% (0.613 mmol/g) compared with ordinary adsorbents and CO₂ removal efficiency of 88.8% within l hour, respectively. It was estimated that the modified adsorbent was applicable to indoor environments.
Competitive solvent extraction of the mixure of alkali metal and alkaline earth cation from water into organic solvent containing the crown ether carboxylic acid and anlogous crown ether phosphonic acid was investigated as follows. The lipophilic group is found to strongly influence to the selective extraction in the mixed systems from only alkali metal cation for sym-(n-decyldibenzo)-16-crown-5-oxyacetic acid _1 to mostly alkaline earth metal cation for sym-bis[4(5)-tert-butylbenzo]-16-crown-5-oxyacetic acid _3. Monoethyl sym-(n-decyldibenzo)-16-crown-5-oxymethylphosphonic acid _2. and monoethyl-sym- bis]4(5)-tert-butylbenzo]-16-crown-5-oxymethylphosphonic acid _4 showed good selectivity for Na+ over Mg2+, the second extracted ion. Structural variation in the crown ether phosphonic acid somewhat was influenced to the extraction selectivity in the mixed systems. when variation of the ionized group is influenced in the mixed systems, the selectivity of Na+ as the second extracted ion was much better crown ether carboxylic acid _1 than crown ether phosphonic acid _2, while the efficiency of Na+ extraction was better _2 (83% total loading) than _1 (32%).
A comparison of alkali metal cation and alkaline earth cation solvent extraction was made for three additional monoionizable crown ethers and one diionizable crown ether. sym-(n-Octyldibenzo)-16-crown-5-oxyacetic acid _1 exhibited high efficiency and selecvity in solvent extraction of alkali metal cations with respect to that observed with alkaline earth cations. Sizes of Na+ and Ca2+ appropriately match with the cavity size of monoethyl sym-bis[4(5)-tert-butylbenzo]-16-crown-5-oxymethylphosphonic acid _3. As the result, Na+ and Ca2+ are the best extracted. sym-(n-Octyldibenzo)-16-crown-5-oxymethyldiphosphonic acid _4was found to be somewhat selective for Na+ over Li+ and other alkaline earth metal cations. In the complexation of alklaine earth cations by crown ether diphosphonic acid _4, Ca2+ and Sr2+ are the appropriate sizes, but lager Ba2+ may be due to favorable formation of a sandwich type complex between the crown ether cavity and the dianion of the deprotonated crown ether phoaphonic acid moiety.
감마선이 조사된 세포막 모델에서 K+ 와 Na+의 선택적 전달특성을 연구하였다. 이 실험에 사용된 세포막 모델은 Na+슬폰화 폴리스티렌-디비닐벤젠(polystyrene-divinylbenzene) 혼성 중합막을 사용하였다. 이온의 초기플럭스는 H+이온 농도의 증가와 함께 증가하였다. 이 실험의 조건을 pH 0.5-3, 온도 15-65℃로 하여 첫 번째 조사되지 않은 막의 K+와 K+/Na+의 선택도는 약 1.06 - 1.13이고 두 번째 조사된 막의 K+와 K+/Na+의 선택도는 약 0에 가깝다. 조사된 막의 pH의 추진력은 조사되지 않은 막보다 약 4-5배 정도 유의성 있게 증가하였다. 세포막모델에서 K+ 와 Na+의 선택적 전달특성이 비정상적이기 때문에 세포장해가 세포에서 발현된다.