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Highly sensitive up-conversion phosphor for optical thermometry:CaLaAl3O7:Er3+/Yb3+

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Journal of Rare Earths 2019年第9期37卷 937-942,I0002页

作者： Peng Gao Xu Li Yi Gong Guangming Shen Suheng Zhang Li Guan hebei Key Laboratory of Photo-Electricity Information and Materials College of Physics Science and Technology Hebei University

Herein,we reported Er^3+/Yb^3+co-doped CaLaAl3O7 up-conversion phosphors synthesized via solid state reaction,which was further explored as a new optical *** luminescent properties of Er^3+or Er^3+/Yb^3+doped CaLaAl3O7 phosphor was studied in *** two-photon process for the green emissions of Er^3+were confirmed by the power-dependent *** up-conversion optical temperature sensing performances of the Er^3+/Yb^3+-codoped CaLaAl3O7 phosphor were investigated based on the FIR *** maximum sensitivity of this phosphor can reach about 0.00345 K-1 at 453 K,which reveals this phosphor can be a promising candidate for optical thermometry devices.

关键词： Luminescence Phosphor Up-conversion FIR Optical thermometry Rare earths

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Chinese physics B 2011年第3期20卷 386-391页

作者：张红翟利学王学张春元刘建军 College of Science Hebei University of EngineeringHandan College of physics Science and Information Engineering Hebei Nornal UniversityShijiazhuang

This paper presents a systematic study of the ground-state binding energies of a hydrogenic impurity in quantura dots subjected to external electric and magnetic fields. The quantum dot is modeled by superposing a lateral parabolic potential, a Gaussian potential and the energies are calculated via the finite-difference method within the effectivemass approximation. The variation of the binding energy with the lateral confinement, external field, position of the impurity, and quantum-size is studied in detail. All these factors lead to complicated binding energies of the donor, and the following results are found：（1） the binding energies of the donor increase with the increasing magnetic strength and lateral confinement, and reduce with the increasing electric strength and the dot size; （2） there is a maximum value of the binding energies as the impurity placed in different positions along the z direction; （3） the electric field destroys the symmetric behaviour of the donor binding energies as the position of the impurity.

关键词： quantum dot hydrogenic impurity binding energy

First-principles study of He trapping in η-Fe_2C

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Chinese physics B 2016年第11期25卷 412-417页

作者：赫丙玲王金龙田之雪蒋利娟宋薇王斌 College of physics and Electronic Engineering Xinxiang University College of physics and Information Engineering Hebei Normal University

The distribution of He in η-Fe2C has been studied by first-principles *** formation energies of interstitial He and substitutional He（replacing Fe） are 3.76 eV and 3.49 eV,respectively,which are remarkably smaller than those in bcc Fe,indicating that He is more soluble in η-Fe2C than in bcc *** binding potencies of both a substitutionalinterstitial He pair（1.28 eV） and a substitutional-substitutional He pair（0.76 eV） are significantly weaker than those in bcc *** binding energy between the two He atoms in an interstitial-interstitial He pair（0.31 eV） is the same as that in bcc Fe,but the diffusion barrier of interstitial He（0.35 eV） is much larger than that in bcc Fe,suggesting that it is more difficult for the interstitial He atom to agglomerate in η-Fe2C than in bcc ***,self-trapping of He in η-Fe2C is less powerful than that in bcc *** a consequence,small and dense η-Fe2C particles in ferritic steels might serve as scattered trapping centers for He,slow down He bubble growth at the initial stage,and make the steel more swelling resistant.

关键词： interstitial trapping Fe_2C powerful dense steels scattered octahedral swelling consequence

Effect of Addition of Nitrogen to a Capacitively Radio-Frequency Hydrogen Discharge

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Plasma Science and Technology 2014年第3期16卷 203-210页

作者：张连珠姚福宝赵国明郝莹莹孙倩 College of physics Science and Information Engineering Hebei Normal University

A hybrid PIC/MC model is developed in this work for H2-xN2 capacitively coupled radio-frequency （CCRF） discharges in which we take into account 43 kinds of collisions reaction processes between charged particles （e-, H3＋, H＋, H＋, N＋, N＋） and ground-state molecules （H2, H＋ N2）. In addition, the mean energies and densities of electrons and ions （ 3, H＋, H＋）, and electric field distributions in the H2-N2 CCRF discharge are simulated by this model. Furthermore, the effects of addition of a variable percentage of nitrogen （0-30%） into the H2 discharge on the plasma processes and discharge characteristics are studied. It is shown that by increasing the percentage of nitrogen added to the system, the RF sheath thickness will narrow, the sheath electric field will be enhanced, and the mean energy of hydrogen ions impacting the electrodes will be increased. Because the electron impact ionization and dissociative ionization rates increase when N2 is added to the system, the electron mean density will increase while the electron mean energy and hydrogen ion density near the electrodes will decrease. This work aims to provide a theoretical basis for experimental studies and technological developments with regard to H2-N2 CCRF plasmas.

关键词： H2-N2 capacitively coupled radio-frequency discharge H2 plasma PIC/MCsimulation

A two-dimensional model of He/O_2 atmospheric pressure plasma needle discharge

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Chinese physics B 2015年第12期24卷 412-421页

作者：钱沐杨杨从影陈小昌刘三秋晏雯刘富成王德真 Department of physics Nanchang University School of physics and Optoelectronic Technology Dalian University of Technology College of physics Science and Technology Hebei University

In this paper, a computational modeling study of stream propagation in the atmospheric-pressure helium plasma in ambient atmosphere（oxygen） is presented. A coupled fluid model between time-dependent plasma dynamics and steady state neutral gas flow is employed to provide a fundamental insight into the evolution of the streamers. The obtained simulation results showing that the sheath forms near the dielectric surface and shields the axial stream propagation. The stream front propagates with axial velocity in a range of 10^4m/s–10^5m/s. And, the increasing accumulated surface charge should be responsible for reducing the propagation velocity of the streamer front in the axial direction. Besides, when the gas flow rate is 1.1 standard liter per minute（SLM）, we find that the concentration of oxygen drastically increases at a larger radial position near a treated surface. Therefore, Penning ionization by helium metastables and oxygen peaks at an off-axis position, corresponding to the ring-shaped emission profile in cylindrical coordinates. In this case, the simulated results show the ring-shaped ground atomic oxygen density profile near the treated surface（z = 0.5 mm） at a large gas flow rate of 1.1 SLM, which is consistent with the observation in a similar experiment.

关键词： atmospheric pressure plasma needle discharge streamer dynamics cathode sheath

Stability of small Ni-Ti bimetallic clusters studied by density functional theory

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Chinese physics B 2010年第4期19卷 185-192页

作者：陈振岗谢尊李有成马庆敏刘英 Department of physics and hebei Advanced Thin Films Laboratory Hebei Normal University Department of Basic Courses Hebei Botou Vocational College

The low-energy structures and the electronic and the magnetic properties of small NinTin （n ： 1-6） and NimTin （1 ≤ n ≤ 4, 1≤m ≤ 4, n ≠m） clusters are investigated by performing all-electron calculations based on density functional theory. Ground states and several isomers near the ground states are determined for these clusters. The results indicate that the growth of small Ni,nTin clusters prefers to form rich Ti-Ni and Ti Ti bonds. When the percentage of titanium atoms is significantly greater than that of nickel atoms, the nickel atoms are most frequently found above the surface; in contrast, the titanium atoms prefer the bridging sites. A Mulliken spin population analysis indicates that the total spin of titanium-nickel clusters is not always zero.

关键词： NimTin clusters lowest-energy structure electronic and magnetic properties

Atomic mass dependence of hadron production in semi-inclusive deep inelastic lepton-nucleus scattering

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Chinese physics C 2013年第8期37卷 29-33页

作者：宋丽华刘娜段春贵 Department of physics Hebei Normal University College of Science Hebei United University College of Mathematics and physics Shijiazhuang University of Economics hebei Advanced Thin Films Laboratory

Hadron production in lepton-nucleus deep inelastic scattering is studied in a quark energy loss model. The leading-order computations for hadron multiplicity ratios are presented and compared with the selected HERMES pions production data with the quark hadronization occurring outside the nucleus by means of the hadron formation time. It is found that the obtained energy loss per unit length is 0.440±0.013 GeV/fm for an outgoing quark by the global fit. It is confirmed that the atomic mass number dependence of hadron attenuation is theoretically and experimentally in good agreement with the A2/3 power law for quark hadronization occurring outside the nucleus,

关键词： atomic mass dependence quark energy loss hadron production deep inelastic scattering

Suppression of Andreev conductance in a topological insulator–superconductor nanostep junction

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Chinese physics B 2016年第3期25卷 338-341页

作者：郑翌洁宋俊涛李玉现 College of physics & Information Engineering and hebei Advanced Thin Films Laboratory Hebei Normal University

When two three-dimensional topological insulators （TIs） are brought close to each other with their surfaces aligned, the surfaces form a line junction. Similarly, three TI surfaces, not lying in a single plane, can form an atomic-scale nanostep junction. In this paper, Andreev reflection in a TI-TI-superconductor nanostep junction is investigated theoretically. Be- cause of the existence of edge states along each line junction, the conductance for a nanostep junction is suppressed. When the incident energy （e） of an electron is larger than the superconductor gap （A）, the Andreev conductance in a step junction is less than unity while for a plane junction it is unity. The Andreev conductance is found to depend on the height of the step junction. The Andreev conductance exhibits oscillatory behavior as a function of the junction height with the amplitude of the oscillations remaining unchanged when e = 0, but decreasing for e = A, which is different from the case of the plane junction. The height of the step is therefore an important parameter for Andreev reflection in nanostep junctions, and plays a role similar to that of the delta potential barrier in normal metal-superconductor plane junctions.

关键词： topological insulator nanostep junction suppression of Andreev conductance

Laser-induced voltage effects in Ca_3Co_4O_9 thin films on tilted LaAlO_3(001) substrates grown by chemical solution deposition

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Chinese physics B 2010年第10期19卷 441-444页

作者：王淑芳陈明敬赵书瑞陈景春何立平于威王江龙傅广生 College of physics Science and Technology Hebei University Department of physics and Electronic Engineering Baoding University

Laser-induced voltage effects in c-axis oriented Ca3Co4O9 thin films have been studied with samples fabricated on 10°tilted LaAIO3 （001） substrates by a simple chemical solution deposition method. An open-circuit voltage with a rise time of about 10 ns and full width at half maximum of about 28 ns is detected when the film surface is irradiated by a 308-nm laser pulse with a duration of 25 ns. Besides, opemcircuit voltage signals are also observed when the film surface is irradiated separately by the laser pulses of 532 nm and 1064 nm. The results indicate that Ca3Co4O9 thin films have a great potential application in the wide range photodetctor from the ultraviolet to near infrared regions.

关键词： laser-induced voltage Ca3Co4O9 thin films chemical solution deposition