The preparation of powder by the Chemical Vapor Synthesis process (CVS) was studied using the liquid metal organic precursor (TTIP). The residence time and the collection methods were considered as main processing variables through the experiments. The CVS equipment consisted of a micropump and a flashvaporizer, a tube furnace and a tubular collection device. The synthesis was performed at with various sets of collection zone. The residence time and the total system pressure were controlled in the range of 3~20 ms and 10 mbar, respectively. Nitrogen adsorption, X-ray diffraction and electron microscopy were used to determine particle size, specific surface area and crystallographic structure. The grain size of the as-prepared powder was in the range of 2~8 nm for all synthesis parameters and the powder exhibited only little agglomeration. The relationship between particle characteristics and the processing variables is reviewed based on simple growth model.

본(本) 시험(試驗)은 주요북방형(主要北方型) 목초(牧草)에 있어서 기상환경(氣象環境)과 예취방법(刈取方法)이 비구조성(非構造性) 탄수화물(炭水化物)의 합성(合成) 및 축적형태(蓄積形態)에 미치는 영향(影響)을 구명(究明)코자 한국(韓國)의 Suweon, Cheju 및 Taekwalyong과 서독(西獨)의 Freising 및 Braunschweig에서 1975~'79년간(年間) 실시(實施)되었다. 공시초종(供試草種)은 orchardgrass

본 연구에서는 지하 콘크리트 구조물의 누수 균열에 사용되는 주입형 누수보수재료의 품질관리 방안으로 규격화된 국제표준 ISO TS 16774, Part 2 Test method for chemical resistance를 이용하여 현재 우리나라 누수보수현장에서 사용하고 있는 주입형 누수보수재료 2계열 (합성고무계, 시멘트계), 3종류 씩, 총 9 종류의 보수재료에 대한 지하 콘크리트 구조물이 처한 화학적 환경의 저항 안정성을 연구·검토하였다. 그 결과, 합성고무계는 RG-3를 제외하고, 산에 대한 저항력을 높일 수 있는 재료적 검토가 필요하고, 시멘트계는 수산화나트륨, 염화나트륨에 대한 저항을 높일 수 있는 재료적 검토의 필요성이 확인되었다. 이러한 결과는 콘크리트 구조물의 화학적 환경에서의 보수재료 선정 시 기본 지 표로 사용가능 할 것으로 판단된다. 또한, 추후에 연구 개발 되는 보수재료의 품질 향상에 반영할 수 있는 기준 자료의 활용을 기대할 수 있다.

The aim of this research was to apply experimental design methodology in the optimization condition of electrochemical oxidation of Rhodamine B(RhB). The reactions of electrochemical oxidation were mathematically described as a function of parameters amounts of current, NaCl dosage, pH and time being modeled by the use of the central composite design, which was used for fitting quadratic response surface model. The application of response surface methodology using central composite design(CCD) technique yielded the following regression equation, which is an empirical relationship between the removal efficiency of RhB and test variable in actual variables: RhB removal (%) = 3.977 + 23.279․Current + 49.124․NaCl － 5.539․pH － 8.863 ․time － 22.710․Current․NaCl + 5.409․Current․time + 2.390․NaCl․time + 1.061․pH․time － 0.570․time2. The model predicted also agree with the experimentally observed result(R2 = 91.9%).

수열법에 의하여 합성된 헥토라이트의 물리화학적 특성을 연구하였다. 조건에 따른 저면간격의 변화양상을 관찰하기 위하여, 가열실험, pH 변화실험 및 유기용매 치환 실험을 수행하였으며, 헥토라이트의 특성평가를 위하여 IR 및 CEC, MB, 팽윤도, 비료면적 등을 측정하였다. 또한 헥토라이트의 기능성 향상을 위한 타물질과의 혼합 가능 고액비를 측정하였다. 가열 실험결과, (001)면의 저면간격은 12.63 a (상온)으로부터 10.19 a (650℃)으로 감소하였고, pH 7인 경우 가장 낮은 저면간격(13.33 a)을 보인 반면, 이를 기준점으로 pH 〉 7과 pH 〈 7인 영역에서 점차 증가하는 추세를 보였다. 유기용매 치환 시, (001)면의 저면간격은 디에틸에테의(12.86 a), 아세토니트릴(13.31a), 메칠알콜(13.59 a), 에칠알콜(14.05 a), 아세톤(15.69 a) 및 에틸렌 글리콜(17.42 a) 순으로 증가하였다. IR 분석 결과, 기존 타연구자들의 결과와 일치하였으며, 치토라이트의 CEC, MB, 팽윤도 및 비교면적은 각각 105 cmol/, 80 cmol/kg, 68~74ml/2g 및 213m2/g이었다. 또한 헥토라이트의 기능성 향상을 위한 타물질과의 혼합 가능비(헥토라이트/증류수)는 2/100 이하임을 확인하였다.

New pyrochlore-type phases(A2B2O7) were synthesized in the systems: CaO-CeO2-TiO2, CaO-UO2(ThO2)-ZrO2, CaO-UO2(ThO2)-Gd2O3-TiO2-ZrO2, 및 CaO-ThO2-SnO2. The starting materials were pressed with the pressure of 200~400 MPa and sintered at 1500~ 1550℃ for 4~8 hours in air and at 1300~ 1350℃ for 5 ~50 hours under oxygen atmosphere. The products were characterized using XRD, SEM/EDS and TEM. In the bulk compositions of CaCeTi2O7, CaThZr2O7,(Ca0.5 GdTh0.5)(ZrTi)O7) (Ca0.5GdTh0.5)(ZrTi)O7, (Ca0.5GdU0.5)(ZrTi)O7 and CaThSn2O7 , pyrochlore was the major phase, together with other oxide phase of2O7 fluorite structure. In the samples with target compositions CaUZr2O2및 Ca0.5 GdU0.5)Zr2TiO7 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.

This research explored the feasibility of preparing and utilizing a preformed polymeric solution of Al(Ⅲ) for coagulation in water treatment. Slow base(NaOH) injection into supersaturated aluminum chloride and aluminum sulfate solutions did produce high yields of Al polymers useful to water treatment applications. The method of characterization analysis was based on timed spectrophotometer with ferron as a color developing reagent. The hydrolytic Al species were divided into monomeric(Ala), polymeric(Alb), and precipitate(Alc) from the difference in reaction kinetics. The analysis of PACㅣ's characteristics showed that the quantity of polymeric Al produced at value of r(OHadded/Al) = 2.2 was 83% of the total aluminum in solution, as showing maximum contents and precipitated Al was dramatically increased when r was increased above 2.35. In addition, the characteristics of polyaluminum sulfate (PAS) showed that polymeric Al contained at r = 0.75 was 18% of the total aluminum in solution. The synthesized PACl and PAS were stable during storing period, as indicating negligible aging effect. The effect of sulfate ion on PACl was dependent on the concentration of sulfate ion. That is, polymeric species decrease and precipitate species increase as sulfate ion concentration increased. It can be concluded that the sulfate cause the formation of Al(OH)3(s) at low pH. However, The effect of calcium ion was negligible for distribution of Al species.

Buserties are known to have layer structures with variable C dimension which depended on the nature interlayer catious and contents of water molecular between edge-sharing [MnO6] octabedral layers. Na-, Ca-, Mg-, and Zn-buserties were synthesized in the laboratory and studied for to know the structural states of water molecules and the role of catious in the buserite structures. With lowering the relative humidity(RH), Ca-buserite begins to dehydrate at 27% RH and proceeds further very slowly. Mg- and Zn- buserite also slow dehydration above 2% RH. With gradual ineveasing temperature Ca- and Zn-buserite show abrupt shifting of 10a peak (10a-phare) toward 7a peak. All of 7a-phare are further dehydrated to 5a-phare by further increasing temperature. It suggests that interlayer catious play a crucial role in the dehydration behavious of buserites. Simulation of one-dimensional X-ray diffraction patterns of buserties show that buserites have three layers of water molecules of different types: the very loosely bound and tightly bend waters, instead of two layers that was regarded by previous authers. The very loosely bound water is sited I open space of the interlayer, the loosely bound water is bound on the tightly bound water by hydrogen bond, and the tightly bond water in coodinately bound on the interlayer catious.