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| 1 | Electronic structure of the SrAl_2O_4:Eu^(2+) persistent luminescence material显示文摘The electronic structure of the strontium aluminate (SrAl2O4:Eu2+) materials was studied with a combined experimental and theoretical approach. The UV-VUV synchrotron radiation was applied in the experimental study while the electronic structure of the non-optimized and optimized crystal structure were investigated theoretically by using the density functional theory. The structure of the va- lence and conduction bands as well as the band gap energy of the material together with the position of the Eu2+ 4f7 8S7/2 ground state were calculated. The calculated band gap energy (6.4 eV) agreed well with the experimental value of 6.6 eV. The valence band consisted mainly of oxygen states whereas the bottom of the conduction band of strontium states. In agreement with the experimental results, the calculated 4f7 8S7/2 ground state of Eu2+ lies in the energy gap of the host. The position of the 4f7 ground state depended on the Coulomb repulsion strength. The position of the 4f7 ground state with respect to the valence and conduction bands was discussed using theoretical and experimental evidence available. | Jorma Hls Taneli Laamanen Mika Lastusaari Janne Niittykoski Pavel Novák | 2009 | Journal of Rare Earths2009，27，4： | 9 |
| 2 | Synchrotron radiation investigations of the Sr_2MgSi_2O_7:Eu^(2+),R^(3+) persistent luminescence materials显示文摘The electronic and defect energy level structure of polycrystalline Sr2MgSi2O7:Eu2+,R3+ persistent luminescence materials were studied with thermoluminescence and different synchrotron radiation spectroscopies (UV-VUV emission and excitation, X-ray absorption near-edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS)). Special attention was paid on the effect of the R3+ co-dopants on the persistent luminescence properties of the materials. Theoretical calculations using the density functional theory (DFT) were carried out simultaneously with the experimental work. The experimental band gap energy (Eg) value of ca. 7.1 eV agreed very well with the DFT value of 6.7 eV. The variation of the Eg value was attempted to relate with the trap structure as well as with the different properties of the R3+ co-dopants. The trap level energy distribution depended strongly on the R3+ co-dopant except for the shallowest trap energy above the room temperature remaining practically the same, however. The different processes in the mechanism of persistent luminescence from Sr2MgSi2O7:Eu2+,R3+ were assembled and their contributions discussed. | Tuomas Aitasalo Jukka Hassinen Jorma Hls Taneli Laamanen Mika Lastusaari Marja Malkamki Janne Niittykoski Pavel Novák | 2009 | Journal of Rare Earths2009，27，4： | 5 |
| 3 | Defect aggregates in the Sr_2MgSi_2O_7 persistent luminescence material显示文摘The crystal and electronic structure of the Eu2+ doped and defect containing Sr2MgSi2O7 persistent luminescence material were studied using the density functional theory(DFT) .The defects may act as energy storage or even luminescence quenching centres in these materials,however their role is very difficult to confirm experimentally.The probability of vacancy formation was studied using the total en-ergy of the defect containing host.Significant structural modifications in the environment of the isolated defects,especially the strontium va-cancy,as well as defect aggregates were found.The experimental band gap energy of Sr2MgSi2O7 was well reproduced by the calculations.The defect induced electron traps close to the host's conduction band were found to act as energy storage sites contributing to its efficient per-sistent luminescence.The interactions between the defects were found to modify both the Eu2+ 4f7 ground state energy as well as the trap structure.The effect of charge compensation induced by the rare earth co-doping on the defect structure and energy storage properties of the persistent luminescence materials was discussed. | Jorma Hls Taneli Laamanen Mika Lastusaari Pavel Novák | 2011 | Journal of Rare Earths2011，29，12： | 2 |
| 4 | Composition and structure of the centromeric region of rice chromosome 8显示文摘 | Wu J Yamagata H Mika H | 2004 | Plant Cell2004，16，： | 1 |
| 5 | Lithiation characteristics of FeVO4 显示文摘 | Masatoshi H Mika E Takashi M | 1997 | Solid State Ionics1997，98，： | 1 |
| 6 | Genetic analyses of an H3N8 influenza virus isolate, causative strain of the outbreak of equine influenza at the Kanazawa Race horse in Japan in 2007显示文摘 | Mika I Makoto N Yuji H | 2008 | J Vet Med Sci2008，70，9： | 1 |
| 7 | Earthworms and pH affect communitiesof nematodes and enchytraeids in forest soil显示文摘 | Mika R Veikko H | 2003 | Biologyand Fertility of Soils2003，38，1： | 1 |
| 8 | Role of urotensin - Ⅱ in peripheral tissue∞ all autocrine/paracfine growth factor显示文摘 | Takanobu Y Mika M Yukio H | 2004 | Peptides2004，25，： | 1 |
| 9 | Born globals: How to reach new business space rapidly显示文摘 | Mika G V H Kirpalani M | 2004 | Interna- tional Business Review2004，13，5： | 1 |
| 10 | Suppression of mutagenesis by 8 - hydroxy - 2 '- deoxyguanosine 5 '- triphosphate ( 7,8 - di- hydro - 8 - oxo - 2 '- deoxyguanosine 5 '- triphosphate ) by human MTH1 ,MTI-I2, and NUDT5 显示文摘 | Mika H Kazuya S Hideyoshi H | 2010 | Free Radic Biol Med2010，48，9： | 1 |
| 11 | The activity of Pt/A1203 diesel oxidation catalyst after sulphur and calcium treatments显示文摘 | TANJA K TOMI K MIKA H MINNAMARI V KAUKO K TONI K TOIVO L JOUKO L RIITFA K | 2010 | Catal Today2010，154，34： | 1 |
| 12 | The Dosophila Toll signaling pathway显示文摘 | Susanna V Wang J H Mika R | 2011 | J Immunol2011，186，： | 1 |
| 13 | Snail-dependent and independent epithelial-mesenchymal transition in oral squamous carcinoma cells显示文摘 | Minna T Reidar G Mika H | 2006 | J Histnchem Cytochem2006，54，11： | 1 |
| 14 | Chronic morphine increases biosynthesis of nitric oxide synthase in the rat spinal cord 显示文摘 | Machelska H Ziolkowska B Mika J | 1997 | Neuroreport1997，8，12： | 1 |
| 15 | Adult-type hypolactasia is not a pre- disposing factor for the early functional and structural changes of ath- erosclerosis: the Cardiovascular Risk in Young Finns Study 显示文摘 | Terho L Nina H Mika K | 2008 | Clin Sci2008，115，9： | 1 |
| 16 | Radiologically and histologically mixed liposarcoma: a report of two biphasic cases显示文摘 | Taichi I Masahito H Mika W | 2003 | Jpn J Clin Oncol2003，33，9： | 1 |
| 17 | Environmental impact of mining activities on the surface water quality in Tibet:Gyama valley 显示文摘 | Xiang H Mika S Egil T G | 2010 | Sci Total Environ2010，40，8： | 1 |
| 18 | Effect of Mg 2+ and Ti IV doping on the luminescence of Y 2 O 2 S:Eu 3+显示文摘 | Jorma H?ls? Taneli Laamanen Mika Lastusaari Marja Malkam?ki Janne Niittykoski Eugeniusz Zych | 2009 | Optical Materials2009，，12： | 1 |
| 19 | Effects of electromagnetic field emitted by cellular phones on the EEG during a memory task显示文摘 | Christina M. Krause Lauri Sillanm?ki Mika Koivisto Anna H?ggqvist Carina Saarela Antti Revonsuo Matti Laine Heikki H?m?l?inen | 2000 | NeuroReport2000，，4： | 1 |
| 20 | Persistent luminescence of Eu^2+ doped alkaline earth aluminates, MAl2O4 : Eu^2+ 显示文摘 | Jorma H Hogne J Mika L | 2001 | J Alloys and Compounds2001，，： | 1 |
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