White Emitting ZnS Nanocrystals： Synthesis and Spectrum Characterization

Spherical organic-bonded ZnS nanocrystals with 4.0 4-0.2 nm in diameter are synthesized by a liquid-solid-solution method. The photoluminescence spectrum of sample （[S^2-]/[Zn^2＋] = 1.0） shows a strong white emission with a peak at 490nm and - 170 nm full widths at half maximum. By Gauss fitting, the white emission is attributed to the overlap of a blue emission and a green-yellow emission, originating from electronic transitions from internal S^2- vacancies level to valence band and to the internal Zn^2＋ vacancy level, respectively. After sealingZnS nanocrystals onto InGaN chips, the device shows CIE coordinates of （0.29,0.30）, which indicates their potential applications for white light emitting diodes.     

椰胡声功率级的半消声室测试

椰胡是具有地方特色的拉弦乐器之一,多用于演奏广东音乐和广东戏曲、曲艺的伴奏。但对其发声强度一直未进行过科学的测试。本文介绍在华南理工大学半消声室内参照ISO(GB)标准对椰胡声功率级的测量工作。由两位资深乐师分别用两把椰胡在pp,mp,f和ff力度下演奏单音、音阶和乐曲,对每一把椰胡的每一测试内容,由十通道测试设备同步测试中心频率为100～10000 Hz的1/3倍频带声压级谱,通过计算获得每把椰胡在演奏每项内容时的声功率级和动态范围。通过对两把椰胡的测试结果进行平均,获得该乐器在演奏上述内容时的典型声功率级数值及频谱。文中并将半消声室内的测试结果与混响室内的测试结果相对比,探讨测试环境对测试结果的影响。民族乐器发声强度及其频谱特性的获得是开展民族音乐厅堂音质研究的基础。     

新型光弹调制干涉具研究

针对单个光弹调制器((Photoelastic Modulator,PEM))干涉具受到材料本身热、力学的限制,产生的最大光程差小,而多个PEM串联又难以控制,且多个PEM界面的多次反射将使光能大量损失等缺点,提出一种在单PEM上贴全反射膜经过多次反射有效提高最大光程的方法。理论推导分析了不同反射情况对光程差的影响,并得到任意角任意位置入射经多次反射后产生最大光程差的公式与光谱反演公式,且通过COMSOL、MATLAB、ZEMAX仿真和实验验证其可行性。实验选用的弹光晶体为硒化锌(ZeSe),压电晶体为石英,结果显示实验与理论的相对误差为0.21%,为该方法的工程应用提供了参考。     

高效液相色谱-串联质谱法测定动物血浆中罗匹尼罗的浓度

建立高效液相色谱-串联质谱(LC-MS/MS)测定动物血浆中罗匹尼罗浓度的方法。血浆经乙酸乙酯萃取后,以HPLC分离,电喷雾离子化(ESI~+)串联质谱检测。以甲醇-乙腈-0.1‰冰醋酸(36:9:55)为流动相,流速为0.2mL·min~(-1),采用Ultimate XB-C 18柱(150mm×2.1mm,3μm)分离,在三级四极杆串联质谱中经电喷雾电离源(ESI)离子化,以多反应监测(MRM)方式进行检测。盐酸罗匹尼罗、盐酸苯海拉明(内标)的扫描离子对m/Z分别为261→114和m/Z 256→167。LC-MS/MS测定血浆中罗匹尼罗线性范围为0.02—400ng·mL~(-1),范围内线性关系良好(r=0.9998);以3个浓度水平的质量控制样品求得各浓度水平日内、日间精密度(RSD)均小于15.2%。在非临床药代动力学研究中,应用此法测定了受试兔子血浆中罗匹尼罗的浓度。该法灵敏、快速、准确,操作简便,样品处理方便,线性范围宽,该方法检测快速、专一、灵敏,可满足罗匹尼罗临床前药代动力学研究和临床药动学研究的要求。     

T型量子点结构中的自旋极化输运过程

我们利用单杂质Anderson模型及运动方程等理论,通过求解格林函数的方法研究了通过T型量子点结构(耦合于铁磁电极和介观环量子点结构)的自旋极化输运过程.研究结果表明,与量子点相耦合的铁磁电极中的极化强度是控制量子点电子输运的重要参数,由此可以达到自旋阀效应.另外我们还发现与量子点相耦合的介观环中的磁通会影响电子自旋向上和自旋向下近藤共振峰的分裂程度,但若加入适当的外磁场,那么这样的分裂将被抵消。     

Single-SOA-Based Ultrahigh-Speed All-Optical Half Subtracter with PolSK Modulated Signals

A novel ultrahigh-speed all-optical half subtracter based on four-wave mixing (FWM) in a single semiconductor optical amplifier (SOA) is proposed. This scheme only requires a single SOA and two input signals without additional light source, so it is quite simple and compact. Due to the polarization-shift-keying (PolSK) modulated signals being used in this scheme, pattern-dependent degradation can be avoided. By numerical simulation, dependence of the critical factors of the logic gate performance, e.g., the output power of logic 1 and extinction ratio (ER), on two input signals power is investigated. In addition, the effect of the gain polarization dependence of SOA is analysed.     

Silica waveguide ring resonators with multi-turn structure

Optical waveguide ring resonator is the basic element of resonator integrated optic gyro (RIOG). In this paper, we report a novel configuration of optical waveguide ring resonator using a multi-turn structure. The characteristic of the light propagating across the crossed waveguides is analyzed using the finite difference beam propagation method. The relationship between the propagation loss and the intersection angle for arbitrary intersecting angles has been analyzed. Some crossed waveguides are fabricated in silica waveguides to verify the theoretical results. On this basis, the influences of the loop numbers and the excess loss of the crossed waveguide on the limited sensitivity of the RIOG have been analyzed. There is a critical intersection angle for certain resonator, only when the intersection angle is bigger than the critical angle, the gyro sensitivity can be improved by increasing the loop numbers. This will be helpful to how to determine the optimum length in resonator for its application in RIOG.     

两种测定果汁中钾磷含量方法的比较与分析

采用微波消解-等离子体发射光谱法同时测定果汁中K、P含量,优化了实验所需的各种条件。与国家标准方法湿法消解-分光光度法的测定结果作了实验比较,结果表明本实验方法更简单、高效,节省了样品的前处理时间,减小了最终结果的误差。该法灵敏度高、线性范围宽、加标回收率高,结果令人满意。     

无菌与带菌盐藻矿质元素含量的比较分析

采用火焰原子吸收光度法分别测定了对数初、中、末期无菌与带菌盐藻细胞及上清液中Mg,Fe,K,Ca,Na,Mn,Zn,Cu,Ni,Cd和Cr的含量。结果表明:(1)该盐藻Mg,Fe,K,Ca和Na的含量在1～10mg.g-1之间,Zn,Cu,Mn和Ni的含量基本在0.1～1 mg.g-1之间,有害金属Cd和Cr的含量极微。(2)无菌与带菌盐藻不同时期矿质元素的变化趋势大致相同,Mg,Fe,K,Ca,Na,Mn和Cu的含量随着培养时间的延长有所下降,Ca下降的最明显;Mg,Fe,K,Ca和Na的含量在上清液中保持稳定,无明显差异,而Cu和Mn含量在对数中后期的上清液中明显增加。(3)无菌与带菌盐藻Mg,K,Cu和Ni的含量差异不大;带菌盐藻的Fe,Ca,Na和Zn的含量在对数中期均显著下降,且低于无菌盐藻;而到对数末期又明显高于无菌盐藻。本实验结果为进一步利用盐藻资源以及深入研究藻菌相互作用机理提供了参考。     

不同叶轮形式下离心泵噪声特性对比研究

针对具有无短叶片和有短叶片两种叶轮形式的离心泵,对设计状态下离心泵内部流场进行了全三维、非定常数值模拟,对比分析了其非定常流场特性和噪声辐射特性。流场分析表明:叶轮叶片和蜗舌的相互作用造成了叶片表面强烈的压力脉动,对长短叶片的叶轮形式,在局部增加长叶片表面压力脉动的同时,短叶片表面的压力脉动保持较低水平;同时能够有效降低泵体进口压力脉动,但出口压力脉动有所增强。以叶轮叶片表面作为声源辐射面,对比分析了两种叶轮的偶极子噪声辐射特性,结果表明:长短叶片结构通过改变声能在频域上的分布,从而能有效降低总声压级。