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Excitation and luminescence of Dy^(3+) ions in PbO-P_2O_5-Ga_2O_3 glass system

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Journal of Rare Earths 2014年第3期32卷 213-216页

作者： M.Soltys L.Zur J.Pisarska w.a.pisarski Institute of Chemistry University of Silesia

Lead phosphate glasses singly doped with Dy^3＋ ions were studied. The samples were prepared in a glove box in order to eliminate hydroxyl groups. Local structures were examined using FT-IR. Excitation and luminescence spectra for Dy^3＋ ions in inves- tigated lead phosphate glasses were registered. Luminescence intensity ratio Y/B related to 4F9/2→^6HJ/2 （where J=15, 13） transitions was determined and luminescence lifetime （ζm） for the 4F9/2 state of Dy^3＋ions were also measured.

关键词： phosphate glasses Dy^3+ ions luminescence rare earths

Local structure and luminescent properties of lead phosphate glasses containing rare earth ions

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Journal of Rare Earths 2011年第12期29卷 1157-1160页

作者： J.Pisarska L.Zur T.Goryczka w.a.pisarski Institute of Chemistry University of Silesia Institute of Materials Science University of Silesia

Local structure and luminescent properties of lead phosphate glasses containing rare earth ions were studied. Optically active ions such as Eu^3＋, Dy^3＋, Tb^3＋ and Er^3＋ were chosen as dopants. The local structure was verified using X-ray diffraction and Fourier transform inflared （FT-IR） spectroscopy. The visible luminescence bands recorded for the studied samples corresponded to ^5D0→^7Fj （J=0÷4） transitions of Eu^3＋, ^4F9/2→^6Hj/2 （J=11÷15） transitions of Dy^3＋, ^5D3→^7FJ, （J＇=1÷6） and ^5Da→^7FJ （J=3÷6） transitions of Tb^3＋, and ^4S1/2→^4I15/2 transitions of Er^3＋.

关键词： lead phosphate glasses rare earth ions local structure luminescent properties

Up-conversion processes of rare earth ions in heavy metal glasses

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Journal of Rare Earths 2011年第12期29卷 1192-1194页

作者： L.Grobelny w.a.pisarski J.Pisarska R.Lisiecki w.Ryba-Romanowski Institute of Chemistry University of Silesia Institute of Low Temperature and Structure Research Polish Academy of Sciences

Heavy metal lead germanate glasses doubly doped with Yb^3＋ and Ln^3＋ ions （Ln=Er, Tin） were investigated. Up-conversion spectra of Er^3＋ and Tm^3＋ were registered under diode-laser excitation of Yb^3＋. Up-conversion luminescence bands corresponded to ^4S3/2→^4I15/2 （green） and ^4F9/2→^4I15/2 （red） transitions of Er^3＋ as well as ^1G4→^3H6 （blue） and ^3Ha→^3H6 （N]R） transitions of Tm^3＋, respectively.

关键词： heavy metal glasses rare earth ions up-conversion luminescence

Energy transfer processes from Yb^(3+) to Ln^(3+) (Ln=Er or Tm) in heavy metal glasses

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Journal of Rare Earths 2014年第3期32卷 273-276页

作者： A.Kos I.Czopek J.Pisarska w.a.pisarski R.Lisiecki w.Ryba-Romanowski University of Silesia Institute of Chemistry Institute of Low Temperature and Structure Research

Heavy metal glasses doubly doped with Yb3＋ and Ln3＋ ions （Ln=Er or Tm） were studied. Glass host matrices were limited to lead borate glass and lead germanate glass. Efficient resonant （yb3＋-Er3＋） and non-resonant （yb3＋-Tm3＋） energy transfer was ob- served for the studied systems. Near-infrared luminescence spectra at 1.53 μm （Er3＋） and 1.9 gm （Tm3＋） were detected under excita- tion of Yb3＋ by 975 nm diode laser line. They corresponded to 4I13/2→4115/2 （Er3＋） and 3F4→3H6 （Tm3＋） transitions of rare earth ions, respectively. The unusual large spectral linewidth nearly close to 110 nm for 4I13/2→4I15/2 transition of Er3＋ ions in lead borate glass was obtained, whereas long-lived near-infrared luminescence at 1.53 gm was detected in lead germanate glass. Quite different situa- tion was observed for yb3＋-Tm3＋ doubly doped glasses. In contrast to lead borate glass, near-infrared （3F4→3H6） luminescence spectra were registered for Tm3＋ ions in lead germanate glasses, only. These phenomena strongly depended on stretching vibrations of glass host, which was confirmed by FT-IR spectroscopy.

关键词： heavy metal glasses rare earth ions energy transfer NIR luminescence

Emission of Eu^(3+) in sol-gel oxyfluoride glass materials obtained by different preparation methods

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Journal of Rare Earths 2014年第3期32卷 269-272页

作者： M.Zadlo B.Szpikowska-Sroka L.Zur R.Czoik w.a.pisarski Institute of Chemistry University of Silesia Szkolna 9 40-007 Katowice Poland

Silica glasses doped with Eu3＋ ions prepared by sol-gel methods were investigated. The X-ray diffraction （XRD） was used to verify the nature of the studied systems. Excitation and emission spectra of Eu3＋ ions in sol-gel glass materials were detected. Red-to-orange luminescence intensity ratios R/O related to integrated intensities of 5D0→TF2 to 5D0→7TF1 transitions and luminescence lifetimes for 5D0 state of Eu3＋ ions were determined. The results indicated that spectroscopic parameters for Eu3＋ ions strongly de- pended on reagents and their relative ratios used for sol-gel glass preparation.

关键词： sol-gel glasses europium ions luminescence rare earths

Superexchange and charge transfer in the nickelate superconductor La_(3)Ni_(2)O_(7) under pressure

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Science China(Physics,Mechanics & Astronomy) 2024年第11期67卷 1-8页

作者： wéi wú Zhihui Luo Dao-Xin Yao Meng wang Center for Neutron Science and Technology Guangdong Provincial Key Laboratory of Magnetoelectric Physics and DevicesSchool of PhysicsSun Yat-sen UniversityGuangzhou 510275China

Recently, a bulk nickelate superconductor La_(3)Ni_(2)O_(7) is discovered at pressures with a remarkable high transition temperature T_(c)~ 80 K. Here, we study a Hubbard model with tight-binding parameters derived from ab initio calculations of La_(3)Ni_(2)O_(7),by employing large scale determinant quantum Monte Carlo and cellular dynamical mean-field theory. Our result suggests that the superexchange couplings in this system are comparable to that of cuprates. The system is a charge transfer insulator as the hole concentration becomes four per site at large Hubbard U. Upon hole doping, two low-energy spin-singlet bands emerge in the system exhibiting distinct correlation properties: while the one composed of the out-of-plane Ni-d_(3z^(2)-r^(2)) and O-p_(z) orbitals demonstrates strong antiferromagnetic correlations and narrow effective bandwidth, the in-plane singlet band consisting of the Ni-d_(x^(2)-y^(2)) and O-p_(x)/p_(y) orbitals is in general more itinerant. Over a broad range of hole doping, the doped holes occupy primarily the d_(x^(2)-y^(2)) and p_(x)/p_(y) orbitals, whereas the d_(3z^(2)-r^(2)) and p_(z) orbitals retain underdoped. we propose an effective t-J model to capture the relevant physics and discuss the implications of our result for comprehending the La_(3)Ni_(2)O_(7) superconductivity.

关键词： superconductivity nickelate superconductors Hubbard model superexchange charge transfer insulator quantum Monte Carlo

Superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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Journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： H.T.Jeong S.w.Lee w.J.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

The superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)with a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the HCPαphase,were examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy was achieved by employing high-ratio differential speed *** best superplasticity was achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),where tensile elongations of 550±600%were *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size was observed at temperatures above 573 ***,it was important to consider this effect when analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow at low strain rates was governed by lattice diffusion-controlled grain boundary sliding,while at high strain rates,lattice diffusion-controlled dislocation climb creep was the rate-controlling deformation *** was concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it was observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps were constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy Superplasticity Severe plastic deformation Grain size Grain growth

Pervasive Attentive Neural Network for Intelligent Image Classification Based on N-CDE’s

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Computers, Materials & Continua 2024年第4期79卷 1137-1156页

作者： Anas w.Abulfaraj Department of Information Systems Faculty of Computing and Information TechnologyKing Abdulaziz UniversityRabigh21911Saudi Arabia

The utilization of visual attention enhances the performance of image classification *** attentionbased models have demonstrated notable performance,but many of these models exhibit reduced accuracy when confronted with inter-class and intra-class similarities and ***-Controlled Differential Equations(N-CDE’s)and Neural Ordinary Differential Equations(NODE’s)are extensively utilized within this ***’s possesses the capacity to effectively illustrate both inter-class and intra-class similarities and differences with enhanced *** this end,an attentive neural network has been proposed to generate attention maps,which uses two different types of N-CDE’s,one for adopting hidden layers and the other to generate attention *** distinct attention techniques are implemented including time-wise attention,also referred to as bottom N-CDE’s;and element-wise attention,called topN-CDE’***,a trainingmethodology is proposed to guarantee that the training problem is sufficiently *** classification tasks including fine-grained visual classification andmulti-label classification,are utilized to evaluate the *** proposedmethodology is employed on five publicly available datasets,including CUB-200-2011,ImageNet-1K,PASCAL VOC 2007,PASCAL VOC 2012,and MS *** obtained visualizations have demonstrated that N-CDE’s are better appropriate for attention-based activities in comparison to conventional NODE’s.

关键词： Differential equations neural-controlled DE image classification attention maps N-CDE’s

The quasi-Gramian solution of a non-commutative extension of the higher-order nonlinear Schr?dinger equation

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Communications in Theoretical Physics 2024年第3期76卷 51-61页

作者： H w A Riaz J Lin Department of Physics Zhejiang Normal UniversityJinhua 321004China

The nonlinear Schr?dinger(NLS)equation,which incorporates higher-order dispersive terms,is widely employed in the theoretical analysis of various physical *** this study,we explore the non-commutative extension of the higher-order NLS *** treat real or complex-valued functions,such as g_(1)=g_(1)(x,t)and g_(2)=g_(2)(x,t)as non-commutative,and employ the Lax pair associated with the evolution equation,as in the commutation *** derive the quasi-Gramian solution of the system by employing a binary Darboux *** soliton solutions are presented explicitly within the framework of *** visually understand the dynamics and solutions in the given example,we also provide simulations illustrating the associated ***,the solution can be used to study the stability of plane waves and to understand the generation of periodic patterns within the context of modulational instability.

关键词： integrable systems Darboux transformation solitons