排序方式: 共有15条查询结果,搜索用时 27 毫秒
1.
Chang Naon Eun Heechul Won Huijun Kim Seonbyeong Seo Bumkyung Kim Yongsoo 《Journal of Radioanalytical and Nuclear Chemistry》2021,330(3):1045-1051
Journal of Radioanalytical and Nuclear Chemistry - Polypropylene (PP) filters are used for the treatment of radioactive liquid waste containing gamma nuclides such as Co-60, and filter physical and... 相似文献
2.
Mi-Seon Jeong Yongsoo Hwang Chul-Hyung Kang 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(1):287-293
A deep geologic disposal is the prime option for the long-term isolation of high-level radioactive waste (HLW) in many countries.
For deeply located repositories, a radionuclide released from a failed waste container moves through the engineered and natural
barriers before it reaches a biosphere. The pseudo-colloid which a radionuclide is adsorbed on a moving natural humic or fulvic
colloid can be generated in a fractured porous medium. The size of a colloid is in general in the order of a hundred nanometer
so that its migration velocity in a fracture is higher than that of a radionuclide due to the hydrochromatic effect. A large
colloid cannot diffuse easily into a surrounding rock. Also, there are many kinds of actinides and these actinides have decay
chains. In this analysis, the canonical form solution is derived for a pseudo-colloid and a solute in a fracture and a surrounding
rock with a realistic inlet boundary condition with multi-member decay chains. It is used the Fortran based a computational
code which uses a special subroutine for the inversion of Laplace transform. Consequently, the role of the pseudo-colloid
in the fractured porous medium is important and also their decay chains aren’t neglected in the performance assessment of
the HLW. 相似文献
3.
Tepavcevic S Zachary AM Wroble AT Choi Y Hanley L 《The journal of physical chemistry. A》2006,110(4):1618-1624
Conducting polymer films are grown by either mass-selected or non-mass-selected, hyperthermal thiophene ions coincident on a surface with a thermal beam of organic monomers of either alpha-terthiophene (3T) or p-terphenyl (3P) neutrals. Previous experiments verified polymerization of both 3T and 3P by 200 eV C(4)H(4)S(+) during surface polymerization by ion-assisted deposition (SPIAD). A wide variety of structures are observed by scanning electron microscopy to form in the SPIAD polythiophene and polyphenyl films. These structures include microscale islands, lamellar structures, fractal-like growth patterns, and nanoscale crystallites. Some of the deposited films diffract X-rays while others show electron micrographs of crystallites. The variation of these patterns with deposition conditions clearly indicate that ion-induced polymerization mediates film morphology through control of ion energy and ion/neutral ratio. Furthermore, these ion-assisted events mediate important thermal processes such as sublimation. 相似文献
4.
Kwon Yongsoo Yang Heejung Chun Wanjoo Kim Myong Jo Yang Jinfeng 《Chemistry of Natural Compounds》2022,58(3):424-425
Chemistry of Natural Compounds - Phytochemical investigation of the MeOH extract of Angelica polymorpha stem led to the isolation of a new chromone (compound 9, named polymorphachromic acid). Based... 相似文献
5.
Naon Chang Huijun Won Chonghun Jung Seonbyeong Kim Heechul Eun Yongsoo Kim 《Molecules (Basel, Switzerland)》2021,26(5)
This study investigates the dissolution behavior of oxide layers containing radionuclides using perfluorocarbon (PFC) emulsion as a reusable medium. Chemicals such as PFC, anionic surfactant, and H2SO4 are used for preparing the PFC emulsion, and emulsified using an ultrasonication process. The FTIR results show O–H stretching that is formed by the interaction of the carboxyl group of the anionic surfactant with the hydroxyl group of water containing H2SO4, and find that the H2SO4 can be homogeneously dispersed in the PFC–anionic surfactant–H2SO4 emulsion. The dissolution test of the simulated Cr2O3 specimen is conducted using PFC emulsion containing KMnO4. Through the weight losses of specimens and Scanning Electron Microscope-Energy Dispersive X-ray Spectrometer (SEM-EDS) analysis, it is confirmed that the Cr2O3 layer on the SUS304 specimen is easily dissolved using PFC emulsion. During the dissolution of the Cr2O3, it is observed that the dispersed H2SO4–KMnO4 became unstable and separated from PFC emulsion. Based on these results, the behavior of the PFC emulsion during the dissolution of the oxide layer is explained. 相似文献
6.
Schlepütz CM Yang Y Husseini NS Heinhold R Kim HS Allen MW Durbin SM Clarke R 《J Phys Condens Matter》2012,24(9):095007
The atomic surface and interface structures of uncoated and metal-coated epi-polished ZnO(0001) Zn-polar wafers were investigated via surface x-ray diffraction. All uncoated samples showed the presence of a fully occupied (1 × 1) overlayer of oxygen atoms located at the on-top position above the terminating Zn atom, a structure predicted to be unstable by several density functional theory calculations. The same oxygen overlayer was clearly seen at the interface of ZnO with both elemental and oxidized metal Schottky contact layers. No significant atomic relaxations were observed at surfaces and interfaces processed under typical device fabrication conditions. 相似文献
7.
The material properties of nanocrystallines are known to generally have a strong dependence on their nanoscale morphology, such as the grain size. The Hall-Petch effect states that the mechanical strength of nanocrystalline materials can vary substantially for a wide range of grain sizes; this is attributed to the competition between intergranular and intragranular deformations. We employed classical molecular dynamics simulations to investigate the morphology-dependent mechanical properties of nanocrystalline copper. The degradation of material properties under thermal load was investigated during fast strain rate deformation, particularly for the grain size. Our simulation results showed that the thermal load on the nanocrystalline materials alters the grain-size behavior of the mechanical properties. 相似文献
8.
Han-Jun Oh Yongsoo Jeong Young-Jik Kim 《Journal of Physics and Chemistry of Solids》2003,64(11):2219-2225
The electrochemical characteristics of alumina dielectric layers were studied using a surface roughness factor and an impedance spectroscopy. From the limiting diffusion current method, the surface area factor of the dielectric anodic layer with low electrical conductivity was estimated to be 1.03. As alumina dielectric films on Al have a variable stoichiometry, the electrochemical behavior of Al2O3 layer can be monitored by evaluating an equivalent circuit with Young impedance of dielectric constant with a vertical decay of conductivity. 相似文献
9.
Min-Seung Choi Young-Ju Lee Jung-Dae Kwon Yongsoo Jeong Ju-Yun Park Yong-Cheol Kang Pung-Keun Song Dong-Ho Kim 《Current Applied Physics》2013,13(8):1589-1593
We investigated the effects of hydrogen plasma treatment on the physical and electrical properties of fluorine-doped tin oxide (FTO) films used for amorphous silicon (a-Si) thin film solar cells. A slight increase in carrier concentration by the hydrogen doping effect was observed for the FTO film exposed to the hydrogen plasma for 5 min. For further exposure to the plasma, the chemical reduction became prominent and resulted in deterioration of the electrical and optical properties of the film. XPS analysis revealed that the chemical reduction of SnO2 to Sn metallic state occurs on the surface region. It was found that the defects formed by hydrogen plasma act as recombination centers at the interface between FTO electrode and p-layer of a-Si solar cells. This phenomenon resulted in the deterioration of the cell performance. The averaged conversion efficiency (6.82%) of the cells on pristine FTO hydrogen substrate was decreased to 5.81% for the cells on FTO treated for 5 min, which is mainly attributed to the decrease in short-circuit current density. 相似文献
10.
Cationic polymerization is induced at the gas-solid interface by hyperthermal organic cations coincident on a surface with a thermal beam of organic monomers. This process, termed surface polymerization by ion-assisted deposition (SPIAD), produces films that maintain the chemical structure of the monomer. A polythiophene film is produced here by SPIAD with 100 eV thiophene ions and terthiophene monomers coincident on Si and indium tin oxide (ITO) substrates held under vacuum. X-ray photoelectron spectroscopy observes enhancement in film growth for SPIAD compared with either thiophene ion or terthiophene exposure alone. Polythiophene films grown by both mass-selected and nonmass-selected ions with coincident terthiophene dosing both display similar fluorescence intensities at two wavelengths characteristic of emission from films of the terthiophene monomer. Raman spectra of films from nonmass-selected ions display several vibrations also observed in terthiophene films. Ions therefore play a critical role in film growth from nonmass-selected ions, in addition to any radical or photochemically driven processes that may also occur. 相似文献