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Author Morozov, V.A.; Posokhova, S.M.; Deyneko, D., V; Savina, A.A.; Morozov, A., V; Tyablikov, O.A.; Redkin, B.S.; Spassky, D.A.; Hadermann, J.; Lazoryak, B., I doi  openurl
  Title Influence of annealing conditions on the structure and luminescence properties of KGd1-xEux(MoO4)2(0\leq x\leq1) Type A1 Journal article
  Year 2019 Publication CrystEngComm Abbreviated Journal Crystengcomm  
  Volume 21 Issue 42 Pages 6460-6471  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract This study describes the influence of annealing temperature on the structure and luminescence properties of KGd1-xEux(MoO4)(2) (0 <= x <= 1). Compounds with the general formula (A ', A '')(n)[(W, Mo)O-4](m) are investigated as luminescent materials for photonic applications such as phosphor-converted LEDs (light-emitting diodes). Herein, the KGd0.8Eu0.2(MoO4)(2) light-rose crystal was grown by the Czochralski technique. Moreover, three polymorphs of KGd1-xEux(MoO4)(2) were present in the 923-1223 K range of annealing temperatures under ambient pressure: a triclinic alpha-phase, a disproportionately modulated monoclinic beta-phase and an orthorhombic gamma-phase with a KY(MoO4)(2)-type structure. The different behaviors of KGd(MoO4)(2) and KEu(MoO4)(2) were revealed by DSC studies. The number and the character of phase transitions for KGd1-xEux(MoO4)(2) depended on the elemental composition. The formation of a continuous range of solid solutions with the triclinic alpha-KEu(MoO4)(2)-type structure and ordering of K+ and Eu3+/Gd3+ cations were observed only for alpha-KGd1-xEux(MoO4)(2) (0 <= x <= 1) prepared at 923 K. The structures of gamma-KGd1-xEux(MoO4)(2) (x = 0 and 0.2) were studied using electron diffraction and refined using the powder X-ray diffraction data. The luminescence properties of KGd1-xEux(MoO4)(2) prepared at different annealing temperatures were studied and related to their different structures. The maxima of the D-5(0) -> F-7(2) integral emission intensities were found under excitation at lambda(ex) = 300 nm and lambda(ex) = 395 nm for triclinic scheelite-type alpha-KGd0.6Eu0.4(MoO4)(2) and monoclinic scheelite-type beta-KGd0.4Eu0.6(MoO4)(2) prepared at 1173 K, respectively. The latter shows the brightest red light emission among the KGd1-xEux(MoO4)(2) phosphors. The maximum and integral emission intensity of beta-KGd0.4Eu0.6(MoO4)(2) in the D-5(0) -> F-7(2) transition region is similar to 20% higher than that of the commercially used red phosphor Gd2O2S:Eu3+. Thus, beta-KGd0.4Eu0.6(MoO4)(2) is very attractive for application as a near-UV convertible red-emitting phosphor for LEDs.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000493072200015 Publication Date 2019-09-20  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1466-8033 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.474 Times cited Open Access (down)  
  Notes Approved Most recent IF: 3.474  
  Call Number UA @ admin @ c:irua:164603 Serial 6304  
Permanent link to this record
 

 
Author Sirotina, A.P.; Callaert, C.; Volykhov, A.A.; Frolov, A.S.; Sanchez-Barriga, J.; Knop-Gericke, A.; Hadermann, J.; Yashina, L.V. pdf  doi
openurl 
  Title Mechanistic studies of gas reactions with multicomponent solids : what can we learn by combining NAP XPS and atomic resolution STEM/EDX? Type A1 Journal article
  Year 2019 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C  
  Volume 123 Issue 43 Pages 26201-26210  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Rapid development of experimental techniques has enabled real time studies of solid gas reactions at the level reaching the atomic scale. In the present paper, we focus on a combination of atomic resolution STEM/EDX, which visualizes the reaction zone, and near ambient pressure (NAP) XPS, which collects information for a surface layer of variable thickness under reaction conditions. We compare the behavior of two affined topological insulators, Bi2Te3 and Sb2Te3. We used a simple reaction with molecular oxygen occurring at 298 K, which is of practical importance to avoid material degradation. Despite certain limitations, a combination of in situ XPS and ex situ cross-sectional STEM/EDX allowed us to obtain a self-consistent picture of the solid gas reaction mechanism for oxidation of Sb2Te3 and Bi2Te3 crystals, which includes component redistribution between the oxide and the subsurface layer and Te segregation with formation of a thin ordered layer at the interface. The process is multistep in case of both compounds. At the very beginning of the oxidation process the reactivity is determined by the energy benefit of the corresponding element oxygen bond formation. Further in the oxidation process, the behavior of these two compounds becomes similar and features component redistribution between the oxide and the subsurface layer.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000493865700019 Publication Date 2019-10-03  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1932-7447; 1932-7455 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.536 Times cited Open Access (down)  
  Notes Approved Most recent IF: 4.536  
  Call Number UA @ admin @ c:irua:164664 Serial 6310  
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Author Sanchez-Barriga, J.; Aguilera, I.; Yashina, L., V; Tsukanova, D.Y.; Freyse, F.; Chaika, A.N.; Callaert, C.; Abakumov, A.M.; Hadermann, J.; Varykhalov, A.; Rienks, E.D.L.; Bihlmayer, G.; Blugel, S.; Rader, O. url  doi
openurl 
  Title Anomalous behavior of the electronic structure of (Bi1-xInx)2Se3across the quantum phase transition from topological to trivial insulator Type A1 Journal article
  Year 2018 Publication Physical review B Abbreviated Journal  
  Volume 98 Issue 23 Pages 235110  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Using spin- and angle-resolved photoemission spectroscopy and relativistic many-body calculations, we investigate the evolution of the electronic structure of (Bi1-xInx)(2)Se-3)(2)Se-3 bulk single crystals around the critical point of the trivial to topological insulator quantum-phase transition. By increasing x, we observe how a surface gap opens at the Dirac point of the initially gapless topological surface state of Bi2Se3, leading to the existence of massive fermions. The surface gap monotonically increases for a wide range of x values across the topological and trivial sides of the quantum-phase transition. By means of photon-energy-dependent measurements, we demonstrate that the gapped surface state survives the inversion of the bulk bands which occurs at a critical point near x = 0.055. The surface state exhibits a nonzero in-plane spin polarization which decays exponentially with increasing x, and which persists in both the topological and trivial insulator phases. Our calculations reveal qualitative agreement with the experimental results all across the quantum-phase transition upon the systematic variation of the spin-orbit coupling strength. A non-time-reversal symmetry-breaking mechanism of bulk-mediated scattering processes that increase with decreasing spin-orbit coupling strength is proposed as explanation.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000452322800003 Publication Date 2018-12-05  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access (down)  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:156240 Serial 7462  
Permanent link to this record
 

 
Author Belik, A.A.; Morozov, V.A.; Deyneko, D.V.; Savon, A.E.; Baryshnikova, O.V.; Zhukovskaya, E.S.; Dorbakov, N.G.; Katsuya, Y.; Tanaka, M.; Stefanovich, S.Y.; Hadermann, J.; Lazoryak, B.I. pdf  url
doi  openurl
  Title Antiferroelectric properties and site occupations ofR3+ cations in Ca8MgR(PO4)7 luminescent host materials Type A1 Journal article
  Year 2017 Publication Journal of alloys and compounds Abbreviated Journal  
  Volume 699 Issue Pages 928-937  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Ca8MgR(PO4)(7) = La, Pr, Nd, Sm-Lu, and Y) phosphates with a beta-Ca-3(PO4)(2) related structure were prepared by a standard solid-state method in air. Second-harmonic generation, differential scanning calorimetry, and dielectric measurements led to the conclusion that all Ca8MgR(PO4)(7) are centrosymmetric and go to another centrosymmetric phase in the course of a first-order antiferroelectric phase transition well above room temperature (RT). High-temperature electron diffraction showed that the symmetry changes from R (3) over barc to R (3) over barm during the phase transition. Structures of Ca8MgR(PO4)(7) at RT were refined by the Rietveld method in centrosymmetric space group R (3) over barc. Mg2+ cations occupy the M5 site; the occupancy of the M1 site by R3+ cations increases monotonically from 0.0389 for R = La to 0.1667 for R = Er-Lu, whereas the occupancy of the M3 site by R3+ cations decreases monotonically from 0.1278 for R = La to 0 for R = Er-Lu. In the case of R = Er-Lu, the M3 site is occupied only by Ca2+ cations. P1O(4) tetrahedra and cations at the M3 site are disordered in the R (3) over barc structure of Ca8MgEu(PO4)(7). Using synchrotron X-ray powder diffraction, we found that annealing conditions do not significantly affect the distribution of Ca2+ and Eu3+ cations between the structure positions of Ca8MgEu(PO4)(7). Luminescent properties of CasMgEu(PO4)(7) powder samples were investigated under near-ultraviolet (n-UV) light. Excitation spectra of CasMgEu(PO4)(7) show the strongest absorption at about 395 nm that matches with commercially available n-UV-emitting GaN-based LED chips. Emission spectra show an intense red emission due to the D-5(0) -> F-7(2) transition of Eu3+. (C) 2016 Elsevier B.V. All rights reserved.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000393727500129 Publication Date 2016-12-24  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0925-8388 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access (down)  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:152665 Serial 7464  
Permanent link to this record
 

 
Author Naberezhnyi, D.; Rumyantseva, M.; Filatova, D.; Batuk, M.; Hadermann, J.; Baranchikov, A.; Khmelevsky, N.; Aksenenko, A.; Konstantinova, E.; Gaskov, A. url  doi
openurl 
  Title Effects of Ag additive in low temperature CO detection with In2O3 based gas sensors Type A1 Journal article
  Year 2018 Publication Nanomaterials Abbreviated Journal  
  Volume 8 Issue 10 Pages 801  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract Nanocomposites In2O3/Ag obtained by ultraviolet (UV) photoreduction and impregnation methods were studied as materials for CO sensors operating in the temperature range 25-250 degrees C. Nanocrystalline In2O3 and In2O3/Ag nanocomposites were characterized by X-ray diffraction (XRD), single-point Brunauer-Emmet-Teller (BET) method, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) with energy dispersive X-ray (EDX) mapping. The active surface sites were investigated using Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) spectroscopy and thermo-programmed reduction with hydrogen (TPR-H-2) method. Sensor measurements in the presence of 15 ppm CO demonstrated that UV treatment leads to a complete loss of In2O3 sensor sensitivity, while In2O3/Ag-UV nanocomposite synthesized by UV photoreduction demonstrates an increased sensor signal to CO at T < 200 degrees C. The observed high sensor response of the In2O3/Ag-UV nanocomposite at room temperature may be due to the realization of an additional mechanism of CO oxidation with participation of surface hydroxyl groups associated via hydrogen bonds.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000451174100057 Publication Date 2018-10-08  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2079-4991 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access (down)  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:156335 Serial 7842  
Permanent link to this record
 

 
Author Marikutsa, A.; Yang, L.; Rumyantseva, M.; Batuk, M.; Hadermann, J.; Gaskov, A. pdf  url
doi  openurl
  Title Sensitivity of nanocrystalline tungsten oxide to CO and ammonia gas determined by surface catalysts Type A1 Journal article
  Year 2018 Publication Sensors and actuators : B : chemical Abbreviated Journal  
  Volume 277 Issue Pages 336-346  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Nanocrystalline tungsten oxide with variable particle size and surface area was synthesized by aqueous deposition and heat treatment for use in resistive gas sensors. Surface modification with 1 wt.% Pd and Ru was performed by impregnation to improve the sensitivity to CO and ammonia. Acid and oxidation surface sites were evaluated by temperature-programmed techniques using probe molecules. The surface acidity dropped with increasing particle size, and was weakly affected by additives. Lower crystallinity of WO3 and the presence of Ru species favoured temperature-programmed reduction of the materials. Modifying WO3 increased its sensitivity, to CO at ambient condition for modification by Pd and to NH3 at elevated temperature for Ru modification. An in situ infrared study of the gas – solid interaction showed that the catalytic additives change the interaction route of tungsten oxide with the target gases and make the reception of detected molecules independent of the semiconductor oxide matrix.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000453066700042 Publication Date 2018-09-09  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0925-4005 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access (down)  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:156219 Serial 8513  
Permanent link to this record
 

 
Author Nakazato, R.; Matsumoto, K.; Yamaguchi, N.; Cavallo, M.; Crocella, V.; Bonino, F.; Quintelier, M.; Hadermann, J.; Rosero-navarro, N.C.; Miura, A.; Tadanaga, K. doi  openurl
  Title CO₂ electrochemical reduction with Zn-Al layered double hydroxide-loaded gas-diffusion electrode Type A1 Journal article
  Year 2023 Publication Electrochemistry Abbreviated Journal  
  Volume 91 Issue 9 Pages 097003-97007  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Carbon dioxide electrochemical reduction (CO2ER) has attracted considerable attention as a technology to recycle CO2 into raw materials for chemicals using renewable energies. We recently found that Zn-Al layered double hydroxides (Zn-Al LDH) have the CO-forming CO2ER activity. However, the activity was only evaluated by using the liquid-phase CO2ER. In this study, Ni-Al and Ni-Fe LDHs as well as Zn-Al LDH were synthesized using a facile coprecipitation process and the gas-phase CO2ER with the LDH-loaded gas-diffusion electrode (GDE) was examined. The products were characterized by XRD, STEM-EDX, BF-TEM and ATR-IR spectroscopy. In the ATR-IR results, the interaction of CO2 with Zn-Al LDH showed a different carbonates evolution with respect to other LDHs, suggesting a different electrocatalytic activity. The LDH-loaded GDE was prepared by simple drop-casting of a catalyst ink onto carbon paper. For gas-phase CO2ER, only Zn-Al LDH exhibited the CO2ER activity for carbon monoxide (CO) formation. By using different potassium salt electrolytes affording neutral to strongly basic conditions, such as KCl, KHCO3 and KOH, the gas-phase CO2ER with Zn-Al LDH-loaded GDE showed 1.3 to 2.1 times higher partial current density for CO formation than the liquid-phase CO2ER.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001082818000001 Publication Date 2023-09-08  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Additional Links UA library record; WoS full record  
  Impact Factor Times cited Open Access (down)  
  Notes Approved Most recent IF: NA  
  Call Number UA @ admin @ c:irua:200340 Serial 9009  
Permanent link to this record
 

 
Author Nakazato, R.; Matsumoto, K.; Yamaguchi, N.; Cavallo, M.; Crocella, V.; Bonino, F.; Quintelier, M.; Hadermann, J.; Rosero-Navarro, N.C.; Miura, A.; Tadanaga, K. doi  openurl
  Title CO2 Electrochemical Reduction with Zn-Al Layered Double Hydroxide-Loaded Gas-Diffusion Electrode (Supporting Information) Type Dataset
  Year 2023 Publication Abbreviated Journal  
  Volume Issue Pages  
  Keywords Dataset; Electron microscopy for materials research (EMAT)  
  Abstract Carbon dioxide electrochemical reduction (CO2ER) has attracted considerable attention as a technology to recycle CO2 into raw materials for chemicals using renewable energies. We recently found that Zn-Al layered double hydroxides (Zn-Al LDH) have the CO-forming CO2ER activity. However, the activity was only evaluated by using the liquid-phase CO2ER. In this study, Ni-Al and Ni-Fe LDHs as well as Zn-Al LDH were synthesized using a facile coprecipitation process and the gas-phase CO2ER with the LDH-loaded gas-diffusion electrode (GDE) was examined. The products were characterized by XRD, STEM-EDX, BF-TEM and ATR-IR spectroscopy. In the ATR-IR results, the interaction of CO2 with Zn-Al LDH showed a different carbonates evolution with respect to other LDHs, suggesting a different electrocatalytic activity. The LDH-loaded GDE was prepared by simple drop-casting of a catalyst ink onto carbon paper. For gas-phase CO2ER, only Zn-Al LDH exhibited the CO2ER activity for carbon monoxide (CO) formation. By using different potassium salt electrolytes affording neutral to strongly basic conditions, such as KCl, KHCO3 and KOH, the gas-phase CO2ER with Zn-Al LDH-loaded GDE showed 1.3 to 2.1 times higher partial current density for CO formation than the liquid-phase CO2ER.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001079191200001 Publication Date  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Additional Links UA library record; WoS full record  
  Impact Factor Times cited Open Access (down)  
  Notes Approved Most recent IF: NA  
  Call Number UA @ admin @ c:irua:200933 Serial 9010  
Permanent link to this record
 

 
Author Ulu Okudur, F.; Batuk, M.; Hadermann, J.; Safari, M.; De Sloovere, D.; Kumar Mylavarapu, S.; Joos, B.; D'Haen, J.; Van Bael, M.K.; Hardy, A. url  doi
openurl 
  Title Solution-gel-based surface modification of LiNi0.5Mn1.5O4-δ with amorphous Li-Ti-O coating Type A1 Journal article
  Year 2023 Publication RSC advances Abbreviated Journal  
  Volume 13 Issue 47 Pages 33146-33158  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract LNMO (LiNi0.5Mn1.5O4-delta) is a high-energy density positive electrode material for lithium ion batteries. Unfortunately, it suffers from capacity loss and impedance rise during cycling due to electrolyte oxidation and electrode/electrolyte interface instabilities at high operating voltages. Here, a solution-gel synthesis route was used to coat 0.5-2.5 mu m LNMO particles with amorphous Li-Ti-O (LTO) for improved Li conduction, surface structural stability and cyclability. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) analysis coupled with energy dispersive X-ray (EDX) showed Ti-rich amorphous coatings/islands or Ti-rich spinel layers on many of the LTO-modified LNMO facets, with a thickness varying from about 1 to 10 nm. The surface modification in the form of amorphous islands was mostly possible on high-energy crystal facets. Physicochemical observations were used to propose a molecular mechanism for the surface modification, combining insights from metalorganic chemistry with the crystallographic properties of LNMO. The improvements in functional properties were investigated in half cells. The cell impedance increased faster for the bare LNMO compared to amorphous LTO modified LNMO, resulting in R-ct values as high as 1247 Omega (after 1000 cycles) for bare LNMO, against 216 Omega for the modified material. At 10C, the modified material boosted a 15% increase in average discharge capacity. The improvements in electrochemical performance were attributed to the increase in electrochemically active surface area, as well as to improved HF-scavenging, resulting in the formation of protective byproducts, generating a more stable interface during prolonged cycling.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001102666700001 Publication Date 2023-11-09  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2046-2069 ISBN Additional Links UA library record; WoS full record  
  Impact Factor 3.9 Times cited Open Access (down)  
  Notes Approved Most recent IF: 3.9; 2023 IF: 3.108  
  Call Number UA @ admin @ c:irua:202091 Serial 9096  
Permanent link to this record
 

 
Author Poppe, R.; Roth, N.; Neder, R.B.; Palatinus, L.; Iversen, B.B.; Hadermann, J. url  doi
openurl 
  Title Refining short-range order parameters from the three-dimensional diffuse scattering in single-crystal electron diffraction data Type A1 Journal article
  Year 2024 Publication IUCrJ Abbreviated Journal  
  Volume 11 Issue 1 Pages 82-91  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Our study compares short-range order parameters refined from the diffuse scattering in single-crystal X-ray and single-crystal electron diffraction data. Nb0.84CoSb was chosen as a reference material. The correlations between neighbouring vacancies and the displacements of Sb and Co atoms were refined from the diffuse scattering using a Monte Carlo refinement in DISCUS. The difference between the Sb and Co displacements refined from the diffuse scattering and the Sb and Co displacements refined from the Bragg reflections in single-crystal X-ray diffraction data is 0.012 (7) angstrom for the refinement on diffuse scattering in single-crystal X-ray diffraction data and 0.03 (2) angstrom for the refinement on the diffuse scattering in single-crystal electron diffraction data. As electron diffraction requires much smaller crystals than X-ray diffraction, this opens up the possibility of refining short-range order parameters in many technologically relevant materials for which no crystals large enough for single-crystal X-ray diffraction are available.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001168018300012 Publication Date 2023-12-14  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2052-2525 ISBN Additional Links UA library record; WoS full record  
  Impact Factor 3.9 Times cited Open Access (down)  
  Notes Approved Most recent IF: 3.9; 2024 IF: 5.793  
  Call Number UA @ admin @ c:irua:205513 Serial 9170  
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