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Spark plasma sintering of UO2 fuel composite with Gd2O3 integral fuel burnable absorber
Papynov E.K.,Shichalin O.O.,Belov A.A.,Portnyagin A.S.,Buravlev I.Yu,Mayorov V.Yu,Sukhorada A.E.,Gridasova E.A.,Nomerovskiy A.D.,Glavinskaya V.O.,Tananaev I.G.,Sergienko V.I. 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.8
The paper studies spark plasma sintering (SPS) of industrially used UO2-based fuel containing integral fuel burnable absorber (IFBA) of neutrons Gd2O3. Densification dynamics of pristine UO2 powder and the one added with 2 and 8 wt% of Gd2O3 under ultrasonication in liquid has been studied under SPS conditions at 1050, 1250, and 1450 C. Effect of sintering temperature on phase composition as well as on O/U stoichiometry has been investigated for UO2 SPS ceramics. Sintering of uranium dioxide added with Gd2O3 yields solid solution (U,Gd)O2, which is isostructural to UO2. SEM with EDX and metallography were implemented to analyze the microstructure of the obtained UO2 ceramics and composite UO2- Gd2O3 one, particularly, open porosity, defects, and Gd2O3 distribution were studied. Microhardness, compressive strength and density were shown to reduce after addition of Gd2O3. Obtained results prove the hypothesis on formation of stable pores in the system of UO2-Gd2O3 due to Kirkendall effect that reduces sintering efficiency. The paper expands fundamental knowledge on pros and cons of fuel fabrication with IFBA using SPS technology.
K. V. Smyrnova,A. D. Pogrebnjak,V. M. Beresnev,S. V. Litovchenko,S. O. Borba‑Pogrebnjak,A. S. Manokhin,S. A. Klimenko,B. Zhollybekov,A. I. Kupchishin,Ya. O. Kravchenko,O. V. Bondar 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.5
Nanostructured multicomponent (TiAlSiY)N coatings were fabricated by the cathodic-arc physical vapor deposition (CAPVD). In this study, a bias potential applied to the substrate was − 200 and − 500 V, and changes in structure and propertiesof coatings were investigated. Samples had a single-phase state with a face-centered cubic (FCC) lattice. Small crystallitesof about 7.5 nm and texture with [110] axis were observed at − 500 V. However, lower bias potential resulted in the formationof crystallites of about 41.6 nm with [111] preferred orientation. Moreover, coatings were characterized by superhardstate and demonstrated low wear, high abrasion and crack resistance. The testing of the polycrystalline cubic boron nitride(PCBN) cutting inserts covered with (TiAlSiY)N revealed an increase in the tool life coeffi cient during cutting by 1.66times in comparison with the base tool material. Therefore, (TiAlSiY)N coating is a perspective material for application asa protective layer in cutting tools.
Sung-Kyun Park,Xiaorong Zhou,Kathryn E. Pendleton,Olga V. Hunter,Jennifer J. Kohler,Kathryn A. O’Donnell,Nicholas K. Conrad 한국당과학회 2018 한국당과학회 학술대회 Vol.2018 No.01
Modification of nucleocytoplasmic proteins with O-GlcNAc regulates a wide variety of cellular processes and has been linked to human diseases. The enzymes O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) add and remove O-GlcNAc, but the mechanisms regulating their expression remain unclear. Here, we demonstrate that retention of the fourth intron of OGT is regulated in response to O-GlcNAc levels. We further define a conserved intronic splicing silencer (ISS) that is necessary for OGT intron retention. Deletion of the ISS in colon cancer cells leads to increases in OGT, but O-GlcNAc homeostasis is maintained by concomitant increases in OGA protein. However, the ISS-deleted cells are hypersensitive to OGA inhibition in culture and in soft agar. Moreover, growth of xenograft tumors from ISS-deleted cells is compromised in mice treated with an OGA inhibitor. Thus, ISS-mediated regulation of OGT intron retention is a key component in OGT expression and maintaining O-GlcNAc homeostasis.
Frequency spectra characterization of noncoding human genomic sequences
O. Paredes,Rebeca Romo‑Vázquez,Israel Román‑Godínez,Hugo Vélez‑Pérez,Ricardo A. Salido‑Ruiz,J. Alejandro Morales 한국유전학회 2020 Genes & Genomics Vol.42 No.10
Background Noncoding sequences have been demonstrated to possess regulatory functions. Its classifcation is challenging because they do not show well-defned nucleotide patterns that can correlate with their biological functions. Genomic signal processing techniques like Fourier transform have been employed to characterize coding and noncoding sequences. This transformation in a systematic whole-genome noncoding library, such as the ENCODE database, can provide evidence of a periodic behaviour in the noncoding sequences that correlates with their regulatory functions. Objective The objective of this study was to classify diferent noncoding regulatory regions through their frequency spectra. Methods We computed machine learning algorithms to classify the noncoding regulatory sequences frequency spectra. Results The sequences from diferent regulatory regions, cell lines, and chromosomes possessed distinct frequency spectra, and that machine learning classifers (such as those of the support vector machine type) could successfully discriminate among regulatory regions, thus correlating the frequency spectra with their biological functions Conclusion Our work supports the idea that there are patterns in the noncoding sequences of the genome.
Studies of N-Doped p-ZnO Layers Grown on c-Sapphire by Radical Source Molecular Beam Epitaxy
S. V. Ivanov,A. El-Shaer,M. Al-Suleiman,A. Bakin,A. Waag,O. G. Lyublinskaya,N. M. Shmidt,S. B. Listoshin,R. N. Kyutt,V. V. Ratnikov,A. Ya. Terentyev,B. Ya. Ber,T. A. Komissarova,L. I. Ryabova,D. R. Kh 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5
We report on the fabrication of p-type ZnO:N layers using radical-source molecular beam epitaxy and post-growth annealing of the samples. Plasma-activated oxygen and nitrogen fluxes are supplied via a single plasma cell. The combination of low growth temperature (350 − 400 ℃), slightly O-rich conditions, and post-growth annealing in the range of 650 − 800 ℃ results in efficient nitrogen pdoping with Hall hole concentration 3 × 1017 cm−3. The details of the structural and the electrical characterizations of the films are discussed. We report on the fabrication of p-type ZnO:N layers using radical-source molecular beam epitaxy and post-growth annealing of the samples. Plasma-activated oxygen and nitrogen fluxes are supplied via a single plasma cell. The combination of low growth temperature (350 − 400 ℃), slightly O-rich conditions, and post-growth annealing in the range of 650 − 800 ℃ results in efficient nitrogen pdoping with Hall hole concentration 3 × 1017 cm−3. The details of the structural and the electrical characterizations of the films are discussed.
Hwang, S.R.,Seo, D.H.,Al-Hilal, T.A.,Jeon, O.C.,Kang, J.H.,Kim, S.H.,Kim, H.S.,Chang, Y.T.,Kang, Y.M.,Yang, V.C.,Byun, Y. Elsevier Science Publishers 2012 Journal of controlled release Vol.163 No.3
The regulation of angiogenesis is an interesting area to consider for novel therapeutic approaches to rheumatoid arthritis (RA). Chemically modified heparins have been developed as possible candidates for angiogenesis inhibitor; however, they have a major clinical drawback in exhibiting poor oral bioavailability. Here, orally absorbable O-desulfated low molecular weight heparin (ODS-LMWH) derivatives were newly synthesized by conjugating 2-O- or 6-O-desulfated LMWH with deoxycholic acid (DOCA) or bisDOCA (a dimer of DOCA), and their physicochemical properties, antiangiogenic potency and pharmacokinetic profiles were assessed. After selecting the best candidate among those derivatives, its therapeutic efficacy on arthritis was investigated in a murine collagen antibody-induced arthritis (CAIA) model. ODS-LMWH derivatives significantly inhibited the capillary-like tube formation of human umbilical vein endothelial cells (HUVECs) and basic fibroblast growth factor (bFGF)-induced angiogenesis in the Matrigel plug assay. Among all the compounds, 6ODS-LHbD showed the highest oral bioavailability in rats (19.3%). In the CAIA mouse model, 6ODS-LHbD (10mg/kg, p.o., S.I.D.) significantly inhibited neovascularization in the joint, the increase of hind-paw thickness, and the structural damage in the bone. Therefore, 6ODS-LHbD would be a promising candidate for an orally active drug for the treatment of RA.
Omelianovych, O.,Dao, V.D.,Larina, L.L.,Choi, H.S. Pergamon Press 2016 Electrochimica Acta Vol. No.
This research develops an efficient catalyst material for counter electrodes (CEs) in dye-sensitized solar cells (DSCs) using an inexpensive and ecologically sustainable manufacturing method. In order to achieve this, bimetallic PtFe nanoparticles are synthesized on an FTO substrate using dry plasma reduction (DPR) under atmospheric pressure. The chemical composition of the Pt<SUB>x</SUB>Fe<SUB>1-x</SUB> (0@?x@?1) alloy was optimized in order to achieve high catalytic activity and excellent electrical properties in the developed material. It is found that the Pt<SUB>0.75</SUB>Fe<SUB>0.25</SUB> alloy exhibits the largest value of |I<SUB>red</SUB>|=1.440mA and the lowest value of R<SUB>ct</SUB>=0.88Ω. As a result, an efficiency of 8.94% with J<SUB>sc</SUB>=15.03mAcm<SUP>-2</SUP>,V<SUB>oc</SUB>=805mV, and FF=74.32% is achieved. The obtained efficiency is higher than that of 8.24% for a device using a Pt<SUB>1</SUB>Fe<SUB>0</SUB> CE. The obtained results indicate that the PtFe alloy fabricated using DPR is an alternative CE material for highly efficient DSCs.
Grisel Corro,O. Vázquez-Cuchillo,F. Bañuelos,A. Cruz-López,J.L.G. Fierro 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.6
Pd-Sn and Pt-Sn catalysts supported on γ-Al2O3 were prepared by co-precipitation and the Pt characterized dispersion of reduced samples was determined by H2 chemisorption for Pt and Pt-Sn catalysts, The Pd dispersion was determined by CO adsorption on Pd and Pd-Sn catalysts. The catalysts were characterized by the electron binding energy values determined by XPS. The results are explained on the basis of the Pt and Pd species electron binding energy changes due to the electronic properties of Sn. The catalytic activity in methane oxidation under lean burn conditions was measured. The results reveal that the tin addition causes a change in the catalytic activity of the supported catalysts, showing a greater catalytic activity on the CH4-O2 reaction for the bimetallic Pd-Sn/ γ-Al2O3. Pd-Sn and Pt-Sn catalysts supported on γ-Al2O3 were prepared by co-precipitation and the Pt characterized dispersion of reduced samples was determined by H2 chemisorption for Pt and Pt-Sn catalysts, The Pd dispersion was determined by CO adsorption on Pd and Pd-Sn catalysts. The catalysts were characterized by the electron binding energy values determined by XPS. The results are explained on the basis of the Pt and Pd species electron binding energy changes due to the electronic properties of Sn. The catalytic activity in methane oxidation under lean burn conditions was measured. The results reveal that the tin addition causes a change in the catalytic activity of the supported catalysts, showing a greater catalytic activity on the CH4-O2 reaction for the bimetallic Pd-Sn/ γ-Al2O3.