The disposal of spent nuclear fuel (SNF) poses a significant challenge due to its high radioactivity and heat generation. However, SNF contains reusable materials, such as uranium and trans-uranium, which can be recovered through aqueous reprocessing or pyrochemical processes. Prior to these processes, voloxidation is necessary to increase reaction kinetics by separating fuels from cladding and reducing the particle size. In the voloxidation, uranium dioxide (UO2) from SNF is heated in the presence of oxygen and oxidized to triuranium octoxide (U3O8), resulting a release of gaseous fission products (FPs), including technetium-99 (Tc-99), which poses a risk to human health and the environment due to its high mobility and long half-life of 2.1×105. To date, various methods have been developed to capture Tc in aqueous solutions. However, a means to capture the gaseous form of Tc (Tc2O7) is essential in the voloxidation. Due to the radioactive properties of technetium isotopes, rhenium is often used as a substitute in laboratory settings. The chemical properties of rhenium and technetium, such as their electronic configurations, oxidation states, and atomic radii, are similar and these similarities indicates that the adsorption mechanism for rhenium can be analogous to that for technetium. In the previous study, a disk-type adsorbent based on CaO developed was effective in capturing Re. However, this study lacked sufficient data on the chemical properties and capture performance of the adsorbent. Furthermore, the fabrication of disk-type adsorbents is time-consuming and requires multiple steps, making it impractical for mass production. This study introduces a simple and practical method for preparing CaO-based pellets, which can be used as an adsorbent to capture Re. The results provide a better understanding of the adsorption behavior of CaO-based pellets and their potential for capturing Tc-99. To the best of our knowledge, this is the first study to apply a CaO-based pellet to capture Re and investigate its potential for capturing Tc-99.

Chu Bamboo Book in Anhui University (vol.2) published in August 2022 (hereinafter referred to as “Anda II” or “An Da Jian”) is the latest collation of the bamboo slips of the Warring States Period in Anhui University by the Research Center for the Development and Application of Chinese Characters of Anhui University, which includes two parts: Zhongni Yue and Cao Mo Chen. Through a preliminary comparison and analysis of the writing phenomena corresponding to the purposes of such articles as Cao Mo Zhi Chen and Zhong Ni Yue in An Da Jian, Cao Mo Zhi Zhen in Shang Bo Jian (Chu Bamboo Book in Shanghai Museum), the author found some special phenomena related to He Wen. For example, although the writing of Cao Mo by An Da Jian seems to have various ways of writing, this way of writing may contain a profound interpretation of the meaning of the text by the scribes at that time. This writing phenomenon is of great value for in-depth consideration: 1.When the two words “Shang Xia (上下)” and “Zhi Suo (之所)” can be taken apart or not, the words that cannot be taken apart are often written as He Wen, and the words that can be taken apart are often not written as He Wen; 2.When the original two words “Jun Zi (君子)” and “Xiao Ren (小人)” cannot be separated, the written form of He Wen may represent a special emphasis. At the same time, through a comparative study of the use of Chinese characters in Cao Mo and Zhongni Yue, we may speculate that although Cao Mo and Zhongni Yue may not belong to the same style of writing, at least in the arrangement of He Wen, There may be some similar writing logic in these two chapters - the speculation about this writing logic may be used in the analysis of other difficult texts in Zhongni Yue.

본 연구는 東晉의 王羲之(303-361)가 쓰고 宋人(米芾(1051-1107)로 추정)이 편찬한『草訣 百韻歌』에서 시작한다. 기존 歌訣 해설과 다르게 본 연구는 전통 이론과 실제 붓을 잡고 쓴 경험을 바탕으로, 宋人이 가결을 통해 후학에게 전달하고자 했던 초서의 요체를 새롭게 밝히고 자 한다. 이로써 전통 이론 중, 초서에게 부여된 ‘積其點畫, 乃成其字’, ‘草以點畫為情性, 使轉 為形質’과 같은 간단명료한 원칙의 의미를 더욱 깊이 있게 이해할 수 있을 것이다. 또한, 초서 문자 구조에 잠재된 변화규칙과 초서의 ‘連綿’, ‘游絲’의 추론과 설명 방식을 고찰할 것이다. 이는 초서 문자의 해독과 초서 문헌의 이해할 수 있게 한다는데 의의가 있다. 본 연구의 방법 및 과정은 크게 4가지로 구분된다. (1) 『草訣百韻歌』 중 간략하게 서술된 초서 변화의 요체를 해석하고, 점을 찍는 것에서부터 선을 연결하고 문자를 구성하는 기본 ‘結字 法’을 상세하게 분석한다. ‘圓筆’, ‘潤筆’, ‘渴筆’, ‘轉筆’ 등의 필법이 포함되며, ‘楷’에서 ‘草’로 전개되는 과정에서 문자의 틀과 필획의 구조 변화도 설명한다. (2) 초서에서 가로획과 세로획의 교차 운용 법칙을 상세하게 분석하고, 나아가 ‘撇捺改筆’, ‘戈法變換’ 등 획과 선의 배치, 한자 구조의 변화 등도 아울러 분석하고 논한다. 이는 초서 쓰기, 읽기, 이해에 이론적이고 과학적 해결법을 제공할 것이다. (3) 초서 章法의 기본을 해석하고 초서 필획 중 虛･實의 분배와 운용 및 ‘計白當黑’, ‘意連形連’과 같은 필획 구성의 요체를 고찰한다. (4) ‘連綿’을 재구조화하고, 초서의 점과 획의 변화 규칙을 활용하여 ‘連綿’, ‘游絲’의 필법 원리를 해석한다. 또한 고문헌의 해석에 응용하여 ‘龍蛇競筆端’에 포함된 초서로 쓰인 한자의 수수께끼를 풀어낼 것이며, 이로써 초서 筆法字學 학습의 중요성과 그 가치를 밝힌다.

The high-temperature stability of YSZ specimens fabricated by die pressure and cold isostatic press (CIP) is investigated in CaCl2-CaF2-CaO molten salt at 1,150 °C. The experimental results are as follows: green density 46.7 % and 50.9 %; sintering density 93.3 % and 99.3 % for die press and CIP, respectively. YSZ foremd by CIP exhibits higher stability than YSZ formed by die press due to denseness dependency after high-temperature stability test. YSZ shows peaks mainly attributed to CaZrO3, with a small t-ZrO2 peak, unlike the high-intensity tetragonal-ZrO2 (t-ZrO2) peak observed for the asreceived specimen. The t-ZrO2 phase of YSZ is likely stabilized by Y2O3, and the leaching of Y2O3 results in phase transformation from t-ZrO2 to m-ZrO2. CaZrO3 likely forms from the reaction between CaO and m-ZrO2. As the exposure time increases, more CaZrO3 is observed in the internal region of YSZ, which could be attributed to the inward diffusion of molten salt and outward diffusion of the stabilizer (Y2O3) through the pores. This results in greater susceptibility to phase transformation and CaZrO3 formation. To use SOM anodes for the electroreduction of various metals, YSZ stability must be improved by adjusting the high-density in the forming process.

In this work, ultra-fine calcium oxide (CaO) powder derived from eggshells is used as the starting material to synthesize mineral trioxide aggregate (MTA). The prepared CaO powder is confirmed to have an average particle size of 500 nm. MTAs are synthesized with three types of fine CaO-based powders, namely, tricalcium silicate (C3S), dicalcium silicate (C2S), and tricalcium aluminate (C3A). The synthesis behavior of C3S, C2S and C3A with ultra-fine CaO powder and the effects of C3A content and curing time on the properties of MTA are investigated. The characteristics of the synthesized MTA powders are examined by X-ray diffraction (XRD), field emission-scanning electron microscope (FE-SEM), and a universal testing machine (UTM). The microstructure and compressive strength characteristics of the synthesized MTA powders are strongly dependent on the C3A wt.% and curing time. Furthermore, MTA with 5 wt.% C3A is found to increase the compressive strength and shorten the curing time.

In this study, the effect of the content of MgO-CaO-Al2O3-SiO2 (MCAS) glass additives on the properties of AlN ceramics is investigated. Dilatometric analysis and isothermal sintering for AlN compacts with MCAS contents varying between 5 and 20 wt% are carried out at temperatures ranging up to 1600℃. The results showed that the shrinkage of the AlN specimens increases with increasing MCAS content, and that full densification can be obtained irrespective of the MCAS content. Moreover, properties of the AlN-MCAS specimens such as microhardness, thermal conductivity, dielectric constant, and dielectric loss are analyzed. Microhardness and thermal conductivity decrease with increasing MCAS content. An acceptable candidate for AlN application is obtained: an AlN-MCAS composite with a thermal conductivity over 70 W/m·K and a dielectric loss tangent (tan δ) below 0.6 × 10−3, with up to 10 wt% MCAS content.

In this study, MgO–CaO–Al2O3–SiO2 (MCAS) nanocomposite glass powder having a mean particle size of 50 nm and a specific surface area of 40 m2/g is used as a sintering additive for AlN ceramics. Densification behaviors and thermal properties of AlN with 5 wt% MCAS nano-glass additive are investigated. Dilatometric analysis and isothermal sintering of AlN-5wt% MCAS compact demonstrates that the shrinkage of the AlN specimen increases significantly above 1,300oC via liquid phase sintering of MCAS additive, and complete densification could be achieved after sintering at 1,600oC, which is a reduction in sintering temperature by 200oC compared to conventional AlN-Y2O3 systems. The MCAS glass phase is satisfactorily distributed between AlN particles after sintering at 1,600oC, existing as an amorphous secondary phase. The AlN specimen attained a thermal conductivity of 82.6 W/m·K at 1,600oC.

감귤(Citrus unshiu Marc.)의 곰팡이(Penicillium digitatum) 발병 억제를 위해 선행연구를 통해 개발된 grapefruit seed extract (GSE) 코팅제와 활성칼슘, 푸마르산, 그리고 미산성 전해수의 병합처리 방법을 개발하였고, 각각의 처리를 통해 항곰팡이 효과가 유의적으로 가장 높은 조건을 최적 병합처리 조건으로 결정하여, 저장 중 감귤의 품질특성과 항곰팡이 효과를 조사하였다. 감귤 시료는 0.2% 활성 칼슘 수용액(0.2% CaO/distilled water (w/w), CaO) 과 0.5% 푸마르산/미산성 전해수(w/w) 수용액(0.5% fumaric acid/ slightly acidic electrolyzed water (w/w), FS), 그리고 CaO와 FS의 혼합액(CaO-FS)으로 3종류의 처리를 하였다. 감귤은 각 처리용액 별로 3분간 침지세척한 후, 카나우바 왁스 대비 1.0% GSE (w/w)와 Tween-80 (25% w/GSE w)을 혼합한 코팅액(GSE 코팅)으로 코팅되었다. 각 처리용액과 GSE 코팅을 병합처리한 결과, CaO-GSE 코팅의 항곰팡이 효과가 유의적으로 높아 최적 병합처리조건으로 결정되었다(p<0.05). 무처리구, GSE 코팅, 그리고 CaO 처리 후 코팅한 감귤(CaO-GSE 코팅)은 4°C에서 35일, 25°C에서 14일간 저장되었다. 25°C에 저장된 CaO-GSE 코팅은 무처리구와 GSE 코팅보다 감귤의 P. digitatum 생장을 효과적으로 억제하였다(p<0.05). 또한 CaO-GSE 코팅은 저장온도에 관계없이 감귤의 경도에 영향을 주지 않았고, 25°C에 저장 했을 시, 무처리구에 비해 유의적으로 높은 경도를 유지하였다(p<0.05). CaO-GSE 코팅은 저장온도와 저장일자에 관계없이 무처리구와 GSE 코팅에 비해 호흡률이 낮았고, 저장 중 감귤의 당도, pH는 무처리구와 유의적으로 비슷한 경향을 보였다. 저장기간에 관계없이 CaO-GSE 코팅의 적정산도는 4°C에서 무처리구와 유의적인 차이가 없었으나, 25°C에서는 무처리구보다 유의적으로 높았다. 저장기간 동안 감귤의 색도 중 명도와 적색도는 저장기간, 저장일자, 그리고 처리여부에 관계없이 저장기간 동안 모든 시료에서 유의적인 차이가 없는 것으로 보였으나, GSE 코팅과 CaO-GSE 코팅의 황색도는 저장일자가 길어질수록 무처리구에 비해 유의적으로 감소하였다. 반면에, 감귤의 아스코르브산 농도, 총 페놀 함량, 항산화능은 모든 온도에서 총 저장기간 동안 CaO-GSE 코팅이 GSE 코팅보다 지속적으로 높게 유지되었다. 그러므로 본 연구에서 개발된 CaO-GSE 코팅은 저장 중 감귤의 P. digitatum 생장억제와 저장 중 감귤의 품질을 유지시켜 감귤의 저장성 증대에 기여할 것이다.

Electrochemical reduction has previously been reported for uranium oxide and mixed oxide nuclear fuel (uranium oxide, plutonium oxide). The laboratory scale electrochemical reduction of plutonium oxide powder is demonstrated in CaCl2- 1wt%CaO. The plutonium oxide contained within a permeable steel basket cathode is sacrificed during the process. A graphite anode is also employed during the reduction, leading to a significant contamination of the product.

It is known that bones get damaged by accidents and aging. Since the discovery of Bioglass, various kinds of ceramics have been also found to bond to living bone; some of these ceramics are already being clinically used as bone-repairing materials. In the present study, antibacterial calcium silicate gel (Ag-30CaO·70SiO2 gel) was prepared by sol-gel method in order to control the microstructure, which is related to the dissolution rate and induction period of apatite formation in body environment. In addition, biological Ag-30CaO·70SiO2 is tested. This was done to impart antimicrobial activity to the 30CaO·70SiO2. Ag ion was added during sol-gel synthesis to replace the H2O added during the making of the 30CaO·70SiO2 gel, which has silver solutions of various concentration. After the sol-gel process, 1N-HNO3 solution was used to wash the gel when synthesizing the gel, in order to maintain the porous structure and remove PEG, water soluble polymers. Then, the apatite forming ability of the sol-gel derived CaO-SiO2 gels was investigated using simulated body fluid (SBF), which had almost the same ion concentration as that of human blood plasma. The gels were analyzed by FT-IR spectroscopy, SEM observation, XRD, and fluorescent microscopy. The apatite was successfully created even after washing the gel; apatite is present in an amorphous state, and was found to affect the concentration of the Ag ion in cells in MC3T3 live & dead assay results. From these results, it is suggested that a good material that can be used to repair defects of nature bone is Ag-30CaO·70SiO2 gel.

The nitrogen solubility and nitride capacity of CaO-SiO2-Al2O3-MgO-CaF2 slag systems were measured by using gas-liquid equilibration at 1773K. The nitrogen solubility of this slag system decreased with increasing CO partial pressure, with the linear relationship between nitrogen contents and oxygen partial pressure being -3/4. This system was expected to show two types of nitride solution behavior. First, the nitrogen solubility decreased to a minimum value and then increased with the increase of CaO contents. These mechanisms were explained by considering that nitrogen can dissolve into slags as "free nitride" at high basicities and as "incorporated nitride" within the network at low basicities. Also, the basicity of slag and nitride capacity were explained by using optical basicity. The nitrogen contents exhibited temperature dependence, showing an increase in nitrogen contents with increasing temperature.

This study shows an air-purification test by the UV lamp on which TiO2 catalyst is deposited with glass fiber in the reactor chamber. This test was based on the fundamental data of air-purifier as assessing a removing ability on various contaminants such as CH3COOH, NH3, NO and SO2 as variation of the TiO2 coating, the wave of UV lamp, and the additive CaO. As a result, the highest decomposing removal ratio was shown when 5-times coated glass fiber was used. It can be due to the recombination reaction of electrons and electron-hole in the loaded CaO. Thus, the decomposing removal ratio increased as the recombination ratio decreased. In addition, it was confirmed that the decomposing removal ratio lowered when CaO was considerably deposited because it hided the lamp of OH-1 radical.

The present study is intended to comparatively investigate the changes in microstructure and tensile properties at room and elevated temperatures in commercial AM50(Mg-5%Al-0.3%Mn) and 0.3 wt%CaO added ECO-AM50 alloys produced by permanent mould casting. The typical microstructure of AM50 alloy was distinctively characterized using two intermetallic compounds, β(Mg17Al12) and Al8Mn5, along with α-(Mg) matrix in an as-cast state. The addition of a small amount of CaO played a role in reducing dendrite cell size and quantity of the β phase in the AM50 alloy. It is interesting to note that the added CaO introduced a small amount of Al2Ca adjacent to the β compounds, and that inhomogeneous enrichment of elemental Ca was observed within the β phase. The ECO-AM50 alloy showed higher hardness and better YS and UTS at room temperature than did the AM50 alloy, which characteristics can be mainly ascribed to the finer-grained microstructure that originated from the CaO addition. At 175˚C, higher levels of YS and UTS and higher elongation were obtained for the ECO-AM50 alloy, demonstrating that even 0.3 wt%CaO addition can be beneficial in promoting the heat resistance of the AM50 alloy. The combinational contributions of enhanced thermal stability of the Ca-containing β phase and the introduction of a stable Al2Ca phase with high melting point are thought to be responsible for the improvement of the high temperature tensile properties in the ECO-AM50 alloy.

폐 PVC전선의 열적분해 특성에 관한 연구를 TGA 및 고정층 반응기를 이용하여 연구하였다. 본 연구에서는 분해온도, 공기유량 및 CaO/ PVC의 비를 실험조건으로 고려하였으며, PVC전선의 열적분해과정에서 발생되는 염화수소 및 독성가스의 제거를 위한 CaO의 첨가에 대한 효과를 검증하기 위하여 PVC 전선의 열적분해 과정에서 생성되는 기상 생성물을 GC/MS를 이용하여 분석하였다. 또한 CaO의 첨가효과를 고찰하고자 액성 생성물에 대한 GC/MS을 함께 수행하였으며, 분해온도, 공기유량 및 CaO/PVC의 비에 따른 액상, 기상 및 고상 잔류물의 수율 변화를 함께 고찰하였다. 본 연구로부터 CaO의 첨가량이 증가할수록 PVC의 열적분해 과정에서 발생되는 염화수소의 제거량이 증가함을 확인하였다.

The transesterification of rapeseed oil, soybean oil, and mixed fat were conducted at 65℃ with Al2O3-supported CaO, 0.8 wt% KOH, 1 wt% NaOH and mixed catalyst. The overall conversion(%) of rapeseed oil indicated to be 96% at the 12:1 molar ratio of methanol to oil, 8 wt% CaO and 2 wt% water. The pH ranges of biodiesel for mixed fat using four catalysts and for three fats using 8wt% CaO were 7.3-9.1, 7.3-7.5, respectively. The volumes of water needed to wash biodiesel from rapeseed oil using 0.8 wt% KOH and 8 wt% CaO were 15 mL and 3 mL.

Calcia (CaO) stabilized cubic-HfO2 is studied by density functional theory (DFT) with generalized gradient approximation (GGA). When a Ca atom is substituted for a Hf atom, an oxygen vacancy is produced to satisfy the charge neutrality. The lattice parameter of a 2×2×2 cubic HfO2 supercell then increases by 0.02 Å. The oxygen atoms closest to the oxygen vacancy are attracted to the vacancy as the vacancy is positive compared to the oxygen ion. When the oxygen vacancy is located at the site closest to the Ca atom, the total energy of HfO2 reaches its minimum. The energy barriers for the migration of the oxygen vacancy were calculated. The energy barriers between the first and the second nearest sites, the second and the third nearest sites, and the third and fourth nearest sites are 0.2, 0.5, and 0.24 eV, respectively. The oxygen vacancies at the third and fourth nearest sites relative to the Ca atom represent the oxygen vacancies in undoped HfO2. Therefore, the energy barrier for oxygen migration in the HfO2 gate dielectric is 0.24 eV, which can explain the origin of gate dielectric leakage.