气源分子束外延生长的InPBi薄膜材料中的深能级中心

利用深能级瞬态谱(DLTS)研究了气源分子束外延(GSMBE)生长的InP1-xBix材料中深能级中心的性质。在未有意掺杂的InP中测量到一个多数载流子深能级中心E1,E1的能级位置为Ec-0.38 e V,俘获截面为1.87×10~(-15)cm~2。在未有意掺杂的InP0.9751Bi0.0249中测量到一个少数载流子深能级中心H1,H1的能级位置为Ev+0.31 eV,俘获截面为2.87×10~(-17)cm~2。深中心E1应该起源于本征反位缺陷PIn,深中心H1可能来源于形成的Bi原子对或者更复杂的与Bi相关的团簇。明确这些缺陷的起源对于InPBi材料在器件应用方面具有重要的意义。     

用清除羟自由基法评价竹叶提取物抗氧化能力

进行了Fe2+与邻二氮菲生成红色配合物的吸收光谱,抗氧化剂TBHQ及竹叶提取物样品对清除羟自由基能力的研究。分光光度法测定抗氧化剂清除羟自由基能力的测定波长为509.1 nm。以IC₅₀值(清除率为50%时,抗氧化剂的浓度值)作为评价抗氧化剂清除羟自由基能力的指标,测得合成抗氧化剂和效果最好竹叶提取物样品IC₅₀值分别为0.040(TBHQ),0.378(M20),0.323(M40),0.334(M60),M20, M40, M60等竹叶提取物可以作为天然抗氧化剂进行开发。     

两种磷光材料在聚合物掺杂体系中的发光特性研究

磷光材料由于可以利用电致激发所形成的单重态和三重态激子,因而可以得到接近100%的内量子效率。文章对常温下基于磷光材料Ir(ppy)₃及Ir(piq)₃掺杂PVK薄膜为发光层的器件的光学和电学特性进行了研究。光致发光的结果显示相同掺杂质量比下由PVK到Ir(piq)₃的能量传递比到Ir(ppy)₃更加困难。通过研究两种掺杂体系不同质量比的电致发光特性,可以认为这两种磷光器件的发光主要来自于磷光客体分子直接俘获载流子发光而非主体的能量传递。Ir(piq)₃掺杂体系对掺杂比例的依赖更为明显,从能级结构分析,认为是由于Ir(piq)₃的更低的HOMO及高的LUMO能级,而比Ir(ppy)₃具有更好的载流子俘获和传输特性。     

Single Production of Charged Top-Pions at High Energy Linear e+e- Colliders

The dominant decay modes of charged top-pions (π±t ) are tb or ~b. We consider the single production ofcharged top-pions in association with a top quark via e+ e- annihilation and calculate the production cross section of theprocesses e+ e- → t-bπ+ (tb-π-) at the leading order. We find that it can reach 1.2 fb with reasonable parameter values.The charged top-pions may be detected via the channel tbπ± in the future high energy e+ e- colliders.     

激波沿H2／空气界面绕圆、方柱强化混合的数值研究

用迎风TVD格式求解二维、层流全N－S方程,对激波沿H2和空气界面绕圆、方柱流动及其诱导的剪切混合进行了数值模拟,得到了流场的压力和组分密度分布,计算结果表明：激波在H2传播得快,剪切层中出现吸涡和调节激波,卷吸涡与柱体撞击后,反射出一道激波,H2沿柱体表面向下游扩散,H2／空气接触面与柱体分离后,形状畸变并产生新的卷吸涡。H2分布表明：在办面上加圆柱或方柱,可有效地强化燃料混合,方柱的增强效果更明显此,在圆柱表面,H2、空气中激波均发生由RR向MR的转变,两Mach杆在下游相互透射,对于方柱,H2中激波中激波沿下表面传播几乎不受影响,空气中激波沿上表面发生Mach反射,其Mach杆和H2中绕射激波相互透射,柱体左侧最终形成一脱体激波,流场存在激波、卷吸涡、接触面向的相互作用,但波系结构相似。     

A Geometrical Model for Tortuosity of Tortuous Streamlines in Porous Media with Cylindrical Particles

We present a three-dimensional geometry model for tortuosity of streamlines in porous media with randomly placed cylindrical particles. The proposed model is expressed as functions of porosity and geometrical parameters with no empirical constant. This might be helpful for understanding the physical mechanism for tortuosity of streamlines in three-dimensional porous media. The model predictions are found to be in good agreement with the experimental data available.     

分光光度法测定家兔体内铁和锰的代谢

为探讨补铁和补锰药物的代谢情况,我们对家兔灌胃中剂量金施尔康多维元素片,每小时对家兔取血,利用邻二氮菲分光光度法测定血样中铁与锰的含量。结果显示:7h铁在家兔血液中含量达到峰值37.86μg·mL-1,10h基本代谢完毕,恢复至正常值28.72μg·mL-1;5h锰在家兔血液中含量达到峰值1.31μg·mL-1,但代谢缓慢,16h后代谢完毕,恢复至正常值0.008μg·mL-1。本实验可为科学补铁、补锰提供一定依据。     

Fabrication and Properties of Double-Side Tl2Ba2CaCu2O8 Thin Film on CeO2 Buffered Sapphire Substrate

The double-side Tl2Ba2 CaCu2O8 （Tl-2212） superconducting thin films were fabricated on CeO2 buffered sapphire substrates. The reactive magnetron sputtering technique was used to grow CeO2 buffer thin films on sapphire substrates. Making use of the metal cerium as a sputtering source, the depositing rate is much higher compared with the CeO2 target. The Ti-2212 thin films on CeO2 buffered sapphire substrates were fabricated by adc magnetron sputtering and post-annealing process. The x-ray diffraction indicates that the thin film is pure Tl-2212 phase with the e-axis perpendicular to the substrate surfaces, and epitaxially grown on the CeO2 buffered sapphire. The critical transition temperature Tc is around 106K, the critical current density Jc is around 3.5 MA/cm^2 at 77K, and the microwave surface resistance R8 at 77K and 10 CHz of the film is as low as 390μ Ω.     

PbWO_4晶体的光输出与能量分辨研究

研究了多种包装材料和包装工艺对钨酸铅(PbWO4)晶体光输出和能量分辨的影响,测量结果与基于GEANT4的模拟结果符合很好,并由此确定了晶体的最佳包装方法。     

Luminescence Properties of Sr2SnO4：Sm^3＋ Afterglow Phosphor

A new long-lasting phosphorescence （LLP） phosphor, Sr2SnO4：Sm3＋ which emits reddish-orange LLP upon UV-excitation, is prepared by a conventional high-temperature solid-state method. After irradiation under 247-nm UV light, Sr2SnO4：Sm3＋ emits an intense reddish-orange emission afterglow from the 4G5/2 to 6HJ （J = 5/2,7/2,9/2） transitions. The afterglow decay curve of the Sm3＋-doped Sr2SnO4 phosphor contains a fast decay component and another slow decay one. Due to the presence of the slow decay component, the afterglow can be seen with the naked eye in the dark clearly for more than 1 h after removal of the excitation source.