β修正光度法测定微量成分及络合比研究：Fe（Ⅱ）－EBT显色体系

在ｐＨ４－５ＨＡｃ－ＮａＡｃ溶液中，Ｆｅ（Ⅱ）与铬黑Ｔ（ＥＢＴ）反应，显色液由蓝变红色。反应较灵敏，ＥＤＴＡ和硫脲可使反应对Ｆｅ２＋具有选择性。本文研究β修正光度法测定微量铁并计算其络合比，该方法能消除显色液中过量显色剂干扰，提高测定灵敏度、准确度和精密度，测定结果表明，铁－ＥＢＴ络合比１：２，相对标准偏差ＲＳＤ≤４．３％，回收率９０．７～１０８％。适合于水及矿石、食品中铁的分析。     

卧式螺旋管内油－气两相流流型的研究

本文在两种不同尺寸的卧式螺旋管内进行了油－气两相流流型的实验研究，得到了流型图，并对各种流型之间的转变机理进行了讨论和分析，同时给出了各流型之间转变的准则关系式。     

KrF准分子激光激发掺锗光纤折射率扰动的非线性过程

本文采用了一种简单的功率监测法,观察了KrF准分子激光对掺锗光纤折射率影响的非线性过程。观察到子纤芯折射率扰动过程中非稳定现象、饱和现象和折射率扰动的非线性。     

Simulation and optimization of reflection optical module design for single LED

Illuminance uniformity and illuminating efficiency are always the key problems of light emitting diode (LED) lighting system design. Based on the new design of the reflection optical module, illuminance uniformity and illuminating efficiency are investigated simultaneously in this paper. At the first stage, a reflector with various profile designs is installed to improve the uniformity and efficiency of irradiances collected through the receiver. Using the macro commands, an effective process is presented through the optimal design of the reflector geometries, and the merit function is used as the optical quality objective to find the optimal design value of $K2$ K 2 and $R2$ R 2 parameters of the reflector. At the second stage, based on the optimal design result, the displacement between LED source and reflector is further adjusted automatically by the macro commands too. The results from the ray tracing simulation indicate that the optimal design can be achieved through the compromise of Illuminance uniformity and illuminating efficiency. Finally, we obtain the merit function value of $1.81$ 1.81 with $K2=-1.09, R2=1.11\,\hbox {mm}$ K 2 = - 1.09 , R 2 = 1.11 mm , and the source position $Z1= 1.68\,\hbox {mm}$ Z 1 = 1.68 mm . The results shown in this paper could be beneficial for machine vision systems which are heavily demanded in the light source applications for the uniform and efficient illuminance.     

Strong coupling superconductivity and prominent superconducting fluctuations in the new superconductor Bi4O4S3

Electric transport and scanning tunneling spectrum(STS)have been investigated on polycrystalline samples of the new superconductor Bi4O4S3.A weak insulating behavior in the resistive curve has been induced in the normal state when the superconductivity is suppressed by applying a magnetic field.Interestingly,a kink appears on the temperature dependence of resistivity near 4 K at all high magnetic fields above 1 T when the bulk superconductivity is completely suppressed.This kink associated with the upper critical field as well as the wide range of excess conductance at low fields and high temperatures is explained as the possible evidence of strong superconducting fluctuation.From the tunneling spectra,a superconducting gap of about 3 meV is frequently observed yielding a ratio of 2Δ/kB TC~16.6.This value is much larger than the one predicted by the BCS theory in the weak coupling regime(2Δ/kB TC~3.53),which suggests the strong coupling superconductivity in the present system.Furthermore,the gapped feature persists on the spectra until 14 K in the STS measurement,which suggests a prominent fluctuation region of superconductivity.Such a superconducting fluctuation can survive at very high magnetic fields,which are far beyond the critical fields for bulk superconductivity as inferred both from electric transport and tunneling measurements.     

ZnO纳米棒／MEH-PPV异质结的复合电致隧穿发光

利用低温水热法生长的ZnO纳米棒（ZnO-NRs）,和p型有机半导体材料聚[2-甲氧基-5-（2-乙基己氧基）-1,4-苯撑乙烯撑]（MEH-PPV）复合制备了结构为“ITO/ZnO晶种/ZnO-NRs/MEH-PPV/Al”的发光器件。测试结果发现,该器件具有非常好的二极管整流特性。对ZnO-NRs/M EH-PPV异质结施加超过17 V的反向偏压时,可同时获得两种半导体材料的发光,且ZnO近紫外光（380 nm ）发射强度远大于 M EH-PPV的红橙光强度,发光功率随着反向偏压的增加迅速增强,然而施加正向偏压时未探测到发光。该器件的发光机理不同于其他文献报道的正偏压发光,而属于反偏压发光器件,其发光机理归因于有机无机复合异质结的界面特殊性和ZnO-NRs的纳米尺寸效应,反偏压下器件实现的是载流子隧穿发光,而正偏压时载流子以表面态的无辐射复合及漏电流方式消耗。     

紫外预电离放电引发的非链式脉冲DF激光器

采用紫外预电离的横向放电方式和稳定光学谐振腔,使用无毒无腐蚀性的六氟化硫(SF6)和氘气(D2)作为工作物质,研究了工作气体配比、总气压对放电引发非链式脉冲氟化氘(DF)激光器输出能量的影响。实验发现SF6与D2的最佳比例为10:1,最佳总气压为10.5 kPa。使用DF激光谱线分析仪对激光输出谱线进行了测量,得到了17条P支跃迁谱线,激光能量集中在3.876μm附近的几条谱线。利用烧蚀光斑的方法测得输出激光束水平方向、垂直方向的发散角均为1 mrad。在最佳工作条件下,充电电压为39 kV时,激光单脉冲输出能量达到最大值3.58 J,此时激光脉冲宽度为215 ns,峰值功率为16.65 MW,电光转换效率为2.08%。     

微波场对(Ba,Sr)3MgSi2O8：Eu2+,Mn2+荧光粉中Mn2+ 660 nm红光能量传递的影响

研究了2.45 GHz微波灼烧(Ba,Sr)₃MgSi₂O₈：Eu²⁺,Mn²⁺荧光粉的非热效应对Mn²⁺离子660 nm红光发射强度的影响。在相同的加热温度条件下,增加微波场的输出功率,微波非热效应导致Eu²⁺离子蓝光的跃迁概率增加,Eu²⁺通过(Ba,Sr)₃MgSi₂O₈基质晶格把能量传递给Mn²⁺,进而使Mn²⁺的跃迁概率增加,导致红光发射增强。提出了一种微波场非热效应对能量传递影响的新观点,认为在微波加热过程中强微波磁场可能会对像Mn²⁺这样具有顺磁性的激活剂离子的能级结构和能量传递性质产生干扰作用。     

吐昔烯衍生物分子的电荷传输性质

根据爱因斯坦方程和Marcus电荷传输模型, 使用密度泛函理论B3lyp/6-31g^**理论水平计算6 个吐昔烯衍生物分子的结构和电荷传输性质. 结果显示: 6个吐昔烯的衍生物分子的空穴迁移速率为0.018–0.062 cm²·V^-1·s^-1, 电子迁移率为0.055–0.070 cm²·V^-1·s^-1, 其中3, 8, 13-辛烷氧基吐昔烯衍生物分子适合作为双极性传输材料. 三条烷氧基链的吐昔烯衍生物分子上引入三个甲氧基或羟基, 均使空穴和电子传输率降低. 引入给电子基团或共轭性基团可减小吐昔烯衍生物分子的能隙, 达到有机半导体的能隙要求. 关键词： 吐昔烯衍生物 空穴传输 电子传输 有机半导体     

频率选择表面天线罩研究现状与发展趋势

由于雷达天线系统自身工作的特点, 他必须保证自身雷达波的正常接收和发射, 常用的隐身措施无法简单地在雷达天线隐身中获得应用. 采用频率选择表面 (FSS) 技术与天线罩技术相结合形成FSS天线罩, 可以使天线罩获得频率选择的功能. 即FSS天线罩对雷达的工作频段提供带通的传输特性, 同时改变雷达工作频段以外的雷达散射截面 (RCS) 特性, 可以实现带外隐身. 本文分析了FSS天线罩制备的基本思路, 综述了国内外FSS天线罩在结构设计、制造工艺等方面的研究状况, 并从多频FSS天线罩、智能FSS天线罩、厚屏FSS天线罩、 微型化FSS天线罩以及各技术的组合等方面对FSS天线罩的发展进行了展望. 关键词： 频率选择表面(FSS) 多频FSS天线罩 智能FSS天线罩 厚屏FSS天线罩