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Concentration effect and temperature quenching of upconversion luminescence in Ba Gd_2ZnO_5:Er^(3+)/Yb^(3+) phosphor

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Journal of Rare Earths 2015年第7期33卷 686-692页

作者：周天民张艳秋吴中立陈宝玖 department of Physics dalian maritime university

Er^3＋/yb^3＋ codoped zincate BaGd2ZnO5 phosphors were synthesized via a traditional solid state reaction. The crystal structure and phase purity were checked by means of X-ray dfluence of Eiffraction （XRD）, and the results showed that pure phase BaGd2ZnO5 phosphors with various Er^3＋/yb^3＋ concentrations were obtained. The Er^3＋ and Yb^3＋ doping concentrations on the green and red upconversion emissions was studied. It was found that both green and red upconversion emissions under 980 nm excitation were two-photon processes independent from the rare earth doping concentrations. However, the upconversion luminescence intensities greatly depended on the rare earth doping concentration. Furthermore, the population processes of upconversion luminescence and the quenching mechanisms were analyzed. The temperature-dependent green upconvcrsion luminescence was studied, and the temperature quenching process of two green upconversion emissions was modeled. The thermal quenching processes of the green upconversion emissions could be well explained by the model we proposed.

关键词： BaGd2ZnO5:Er^3+/yb^3+ phosphor solid state reaction upconversion crossover rare earths

Effect of the Discharge Voltage on the Performance of the Hall Thruster

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Plasma Science and Technology 2016年第4期18卷 382-387页

作者：段萍刘广睿边兴宇陈龙殷燕曹安宁 department of Physics Dalian Maritime University

In this paper,a two-dimensional physical model is established according to the discharging process in the Hall thruster discharge channel using the particle-in-cell *** influences of discharge voltage on the distributions of potential,ion radial flow,and discharge current are investigated in a fixed magnetic field *** is found that,with the increase of discharge voltage,especially during 250-650 V,the ion radial flow and the collision frequency between ions and the wall are decreased,but the discharge current is *** electron temperature saturation is observed between 400-450 V and the maximal value decreases during this *** the discharge voltage reaches 700 V,the potential distribution in the axis direction expands to the anode significantly,the ionization region becomes close to the anode,and the acceleration region grows ***,ion radial flow and the collision frequency between ions and the wall are also increased when the discharge voltage exceeds 650 V.

关键词： Hall thruster particle-in-cell discharge voltage discharge efficiency

Upconversion photoluminescence properties of SrY_2O_4:Er^(3+),Yb^(3+) under 1550 and 980 nm excitation

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Journal of Rare Earths 2016年第5期34卷 458-463页

作者：沈显良邢明铭田莹付姚彭勇罗昔贤 Physics department Dalian Maritime University

Er^3＋/Yb^3＋ co-doped SrY2O4 phosphors with high color purity and brightness were successfully synthesized via a solid-state reaction *** spectrum studies showed that the main red peaks and the minor green peaks of upconversion emissions were located at approximately 634–681 nm and 543–570 nm,respectively,corresponding to the transitions of ~4F（9/2）→~4I（15/2） and ~4S（3/2）→~4I（15/2） of Er^3＋ *** the excitation of 980 and 1550 nm lasers,the spectra of all of the samples exhibited similar peak positions but different *** excited by the 980 nm laser,the intensity ratio of red to green emission increased with increasing Yb^3＋ doping concentration and decreased with increasing excitation *** the case of 1550 nm excitation,the intensity ratio of red to green emission increased with increasing Yb^3＋ doping concentration and excitation power,thereby,improving the color purity of the red *** intensity of red emission was considerably stronger under 1550 nm excitation than that under 980 nm ***,the color of the proposed phosphors could be efficiently tuned by tailoring both the Yb^3＋ doping concentration and excitation power.

关键词： solid-state reaction method upconversion luminescence SrY2O4 Er^3+/Yb^3+ co-doped rare earths

Proper Management of the Asia-Pacific Affairs—— On the Division-and-integration of the Asia-Pacific Region and the Regional Integration Strategy

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学术界 2015年第8期 257-261页

作者： Shao Shuai Guo Ping department of maritime law dalian maritime university

The international administrative theory is the essential tool of the international and regional integration,but it lacks macro reference of history. Based on the regional society system of ancient China,this paper discusses international administrative tools including countries,nations and people,and makes comparison of the economic capital,administrative organization and institutional norm of Europe,America and Asia. Through research,this paper concludes that the regional theory of China has both historic and practical significance.

关键词：区域一体化国际管理亚太地区事务行政组织历史意义社会系统工具包

Composition-dependent optical transitions and 2.0 μm emission properties of Ho^(3+) in xGeO_2-(80-x)TeO_2-9.5ZnF_2-10NaF-0.5Ho_2O_3 glasses

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Journal of Rare Earths 2011年第10期29卷 924-928页

作者：郑燕峰陈宝玖孙佳石程丽红仲海洋李香萍张金苏田跃于婷婷黄丽波 department of Physics Dalian Maritime University

Ho3＋ doped glasses with various compositions xGeO2-（80-x）TeO2-9.5ZnF2-1ONaF-O.5Ho203 （x=, 10, 20, 30, 40, 50, 60, 70 and 80） were prepared by a melt-quenching technique. The composition-dependent optical transition properties of Ho3＋ were investigated in the framework of Judd-Ofelt theory. The emission cross sections for5I7→5I8 transition of 1-Io3＋ in these glasses were calculated according to McCumber theory, and their compositional dependence was discussed. A simple method was proposed in calculating the emission cross sections of 5I7→5I8 transition, and the calculation results were compared with those derived from McCumber theory. Finally, the optical gain coefficient spectra for 5I7→5I8 transition were also analyzed.

关键词： Judd-Ofelt theory Ho3+ mid-infrared cross-section tellurite-germanate glass rare earths

Design and achieving of multicolor upconversion emission based on rare-earth doped tellurite glasses

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Journal of Rare Earths 2014年第5期32卷 394-398页

作者：邢明铭马运北罗昔贤付姚姜涛汪红段小龙 Physics department Dalian Maritime University

yD3＋/Tm3＋ co-doped and yD3＋/Ho3＋/Tm3＋ tri-doped tellurite glasses were synthesized by fusing the mixture of TeO2, PbF2, AIF3, BaF2, Yb2O3, Tm203 and H0203 in a cortmdum crucible at 850 ℃ for 20 min. The synthesized glasses were characterized by upconversion emission spectra under the excitation of 980 nm laser, and the emission colors were investigated according to the CIE-1931 standards. The results indicated that yD3＋/Tm3＋ co-doped tellurite glass exhibited blue upconversion emission with favor- able color coordinates of （0.20, 0.07）. Yb3＋, HO3＋ and Tm3＋ tri-doped tellurite glasses presented white upconversion luminescence under a single 980 nm laser excitation. Moreover, a very wide range of emission colors could be tuned by altering Ho3＋ concentration. Combining the contribution of adjusting Ho3＋ concentration and pump power, near equal energy white light was obtained.

关键词： tellurite glass upconversion luminescence multicolor emission rare earths

Stable Structure and Characteristic Spectroscopy of (CH_3COCH_3)_n (n=1～7) Clusters

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Chinese Journal of Structural Chemistry 2008年第3期27卷 316-320页

作者：许雪松 department of Physics Dalian Maritime University

The stable acetone molecule clusters have been studied by using Becke＇s threeparameter （B3LYP） density functional theory （DFT） with standard 6-31G（d） basis set. The calculated results show that the optimal structures of acetone clusters are cyclic and the cycles become larger and larger with the increase of cluster size. The strongest vibration peaks for neutral clusters are C=O stretching vibration. The C=O stretching peaks of cyclic acetone clusters split into double ones when n≥3, the frequencies are red-shifted and corresponding intensifies increase with the increase of cluster Size.

关键词： clusters vibration spectra density functional theory

Preparation and stabilization of γ-La_2S_3 at low temperature

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Journal of Rare Earths 2011年第4期29卷 313-316页

作者：罗昔贤张明马禄彬彭勇 Physics department Dalian Maritime University

Eu doped γ-La2S3 were synthesized by the sulfurization of their oxide powders using CS2 gas at 700 ℃. During the sulfurizing reaction process, the cubic Eu3S4 crystals of prior formation acted as the nuclei sites of the γ-La2S3 phase to facilitate the nucleation process. The γ-La2S3 transformation occurred at significantly lower temperature by the combined contributions of low transformation enthalpy and induced multiple nuclei. On the other hand, the doped Eu ions could be inserted into the empty tetrahedral S4 cavities to stabilize the γ-La2S3 phase at temperature excess of 1100 ℃.

关键词： rare earth sesquisulfide rare earth sulfide La2S3 crystal growth

Experimental optimum design and luminescence properties of NaY(Gd)(MoO_4)_2:Er^(3+)phosphors

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Chinese Physics B 2016年第6期25卷 201-205页

作者：孙佳石徐赛李树伟石琳琳翟梓会陈宝玖 department of Physics Dalian Maritime University

Three-factor orthogonal design（OD） of Er3＋/Gd3＋/T（calcination temperature） is used to optimize the luminescent intensity of Na Y（Gd）（MoO4）2：Er3＋***,the uniform design（UD） is introduced to explore the doping concentration range of Er3＋/Gd3＋.Then OD and range analysis are performed based on the results of UD to obtain the primary and secondary sequence and the best combination of Er3＋,Gd3＋,and T within the experimental *** optimum sample is prepared by the high temperature solid state *** excitation and emission spectra of the optimum sample are *** intense green emissions（530 nm and 550 nm） are observed which originate from Er3＋2H11/2→4I15/2and4S3/2→4I15/2,*** effect is investigated in the optimum NaY（Gd3＋）（MoO4）2：Er3＋phosphors,and the green emission intensity decreases as temperature increases.

关键词： orthogonal design(OD) uniform design(UD) NaY(Gd)(MoO4)2 Er3+ luminescent intensity