Effects of europium concentration on luminescent and scintillation performance of Cs0.2Rb0.8Ca1-xEuxBr3(0≤x≤0.08)crystals

A series of Cs_0.2Rb_0.8Ca_1-xEu_xBr₃(0≤x≤0.08)crystals doped with different concentrations of Eu²⁺were grown using the Bridgman-Stockbarger method.The work describes the influence of Eu²⁺concentration on the luminescent and kinetic properties of Cs_0.2Rb_0.8Ca_1-xEu_xBr₃ crystals,as well as on their scintillation performance.The maximum in the radioluminescence spectra of these crystals shifts from 439 to446 nm with increasing europium concentration.The scintillation decay times of Cs_0.2Rb_0.8Ca_1-xEu_xBr₃ lengthen with the Eu²⁺content.The best light output of 33600photons/MeV is obtained for Cs_0.2Rb_0.8Ca_0.93Eu_0.07Br₃,and the best energy resolution of 6.9%is found for Cs_0.2Rb_0.8Ca_0.94Eu_0.06Br₃.     

Zn_(1-x)Mn_xS稀磁半导体的水热法制备及其性能

以乙二胺为修饰剂,采用水热法合成了不同掺杂比例的Zn_(1-x)Mn_xS(x=0,0.02,0.05,0.07)稀磁半导体材料,并通过XRD、FESEM、HRTEM、XEDS、光致发光光谱(PL)和振动样品磁强计(VSM)对样品的晶体结构、形貌、光学性能和磁学性能进行表征。实验结果表明:本方法制备的所有样品具有结晶良好的纤锌矿结构,没有杂峰出现;样品形貌为一维的纳米棒状,分散性良好;掺杂的Mn2+以替代Zn2+的形式进入到ZnS晶格中,随着Mn掺杂量的增加晶格常数呈现收缩趋势;样品的PL光谱存在明显的紫外发光峰、蓝光发光峰和绿光发光峰,而且峰位发生蓝移;同时一定量的Mn掺杂ZnS纳米晶在室温条件下具有铁磁性。     

Efficient improvement of 2.7 μm luminescence of Er~(3+):oxyfluoride glass containing gallium by Yb~(3+) ions codoping

Mid-infrared laser materials with low phonon energy have significant applications. However, the development of available glass systems for high-power laser gain medium have posed a great challenge.Therefore, we investigated the 2.7 μm spectroscopic properties of Er~(3+)/Yb~(3+) -codoped oxyfluoride glass containing gallium, which were prepared by typically melting and quenching methods. The 2.7 μm luminescence properties of the Er~(3+)/Yb~(3+)-codoped oxyfluoride glass containing gallium were recorded by a 980 nm laser diode. The Judde Ofelt parameters, decay curves, emission cross section, energy transfer efficiency and quantum efficiency were calculated. The maximum emission cross section of YbFGa-0.5 is 1.63 × 10~(-20) cm~2 by 980 nm excitation. The energy transfer efficiency is calculated to be77.8% for the YbFGa-0.5 glass around 2700 nm. The quantum efficiency at 1530 nm is 65.6%. The result reveals that the best doping concentration ratio of Er~(3+):Yb~(3+) ions is 1:0.5, and suggests an effective energy transfer from Yb~(3+) to Er~(3+) ions.     

ZnO:Si透明导电薄膜厚度对其光电性能的影响

目的研究ZnO∶Si薄膜厚度对其生长速率、结晶度、光透率和电阻率的影响。方法用直流磁控溅射系统在玻璃基片上沉积不同的时间,获得5个厚度不同的ZnO∶Si薄膜样品,对比研究了其薄膜生长取向和结构特性、微观形貌、电学参数及透过率曲线。结果 5个ZnO∶Si薄膜样品都为多晶膜,具有单一的(002)衍射峰,沿垂直于基片的c轴方向择优生长。当薄膜厚度从207.6 nm增加到436.1 nm时,薄膜的晶粒尺寸增大,晶化程度提高,电阻率变小;膜厚增至497.8 nm时,薄膜的晶化程度反而降低,电阻率增加。在可见光范围内,5个薄膜样品的平均透过率都高于91.7%。结论膜厚对ZnO∶Si薄膜的电学性能有较大影响,对光学性能的影响则较小。     

Synthesis and Electrical Conductivities of Sm2O3-CeO2 Systems

Solidoxidefuelcell(SOFC)hasattracteda greatattentionasapromisingtechniqueforelectrical powergeneration[1].Thecurrentstate of the art SOFCsusesyttriastabilizedzirconia(YSZ)electro lyte,operatesat800～1000℃duetothelowoxy genionicconductivityoftheYSZelect…     

草酸共沉淀制备超细Ce0.8Sm0.2O1.9工艺优化

掺杂铈基电解质由于具有高电导率用于中温固体氧化物电解质材料.实验采用草酸盐共沉淀法制备20%(摩尔分数)Sm2O3掺杂CeO2(Ce0.8Sm0.2O1.9)氧化物粉末,采用XRD、SEM分析粉末的相结构和颗粒形貌,500℃～1000℃煅烧草酸沉淀物,得到氧化物粉末.XRD分析结果表明,Ce0.8Sm0.2O1.9为立方萤石结构,表明在低温合成了纯相的Sm2O3掺杂CeO2固溶体.激光粒度分析仪分析沉淀反应过程中草酸盐沉淀物和氧化物粉末的粒度分布.通过优化沉淀反应pH值、溶液浓度、添加表面活化剂及沉淀物水洗和干燥处理等制备工艺条件,实现对沉淀反应过程中草酸沉淀物的团聚控制,得到分散良好的亚微米草酸共沉淀物,进一步选择合适煅烧温度,得到亚微米级超细Ce0.8Sm0.2O1.9粉末.     

Li_2CaSiO_4:Dy~(3+)发光性能研究

Dy3+掺杂浓度对Li2CaSiO4:Dy3+发光强度、色坐标、衰减行为的影响进行了系统研究。结果表明Li2CaSiO4:Dy3+能被近紫外光有效激发,产生Dy3+特征的蓝光和黄光;Dy3+最优掺杂浓度为2.5%,衰减寿命为0.78 ms;色坐标CIE位于白光区域;Li2CaSiO4:Dy3+是一种潜在的白光LED用荧光粉。     

基于拉曼放大和掺铒光纤激光器的远程无源传感系统

提出了一种包含拉曼放大和掺铒光纤激光器的远程无源传感系统。该系统中拉曼放大的剩余泵浦功率可用作掺铒光纤激光器的泵浦源,产生的激光信号作为传感信号省略了额外的传感光源。由于拉曼放大作用,可以实现75km长距离无源传感而获得超过40dB的高信噪比。     

Electrosynthesis of the molybdenum disulphide thin films and characterization

Thin films of molybdenum disulphide have been prepared by electrodeposition from an aqueous bath by using molybdenum trioxide and sodium thiosulphate as Mo⁺ ion and S⁻² ion sources, respectively. The films deposited onto stainless steel and fluorine doped tin oxide (FTO) glass substrates were adherent to the substrate. X-ray diffraction studies show that films are polycrystalline. SEM shows films are continuos and uniform. Optical absorption gives a bandgap energy of 1.7 eV.     

Characterization of poly(indole‐5‐carboxylic acid) in aqueous rechargeable cells

Self-doped poly(indole-5-carboxylic acid) (P5CO₂H) is electrodeposited from acetonitrile containing 0.1M LiClO₄ as electrolyte and characterized by UV–vis, IR, cyclic voltammetry, and scanning electron microscopy techniques. The polymer is evaluated as a cathode active material together with a Zn anode in rechargeable cells containing 1M ZnSO₄ at pH 5. The cell shows an open circuit voltage of 1.36 V and a specific capacity of 67 Ah kg⁻¹. The ac impedance study shows a predominant diffusion mechanism. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 917–922, 2005