α1受体阻滞剂类药物与某些同多酸根的共振瑞利散射光谱及其分析应用

在酸性介质中,钼酸根、钨酸根等同多酸根与盐酸哌唑嗪(PRH)和甲磺酸多沙唑嗪(Dox)等α1受体阻滞剂反应形成离子缔合物时,会导致体系的共振瑞利散射(RRS)显著增强并出现新的RRS光谱,最大散射峰分别位于367 nm(钼酸根体系)和290 nm(钨酸根体系)。 PRH和Dox与同多酸根的反应产物具有相似的RRS光谱特征。 其反应的适宜酸度分别为pH值2.1～2.3(钼酸根-PRH体系)和pH值3.1～3.3(钨酸根-PRH体系)。 在一定浓度范围内,不同的反应体系RRS强度增强程度与药物浓度成正比,均可用于痕量药物的测定。 反应具有很高的灵敏度,不同同多酸对PRH的检出限(3σ/s)分别为4.76 μg/L(钼酸根-PRH体系)和9.88 μg/L(钨酸根-PRH体系)。 方法也具有较好的选择性,用于片剂和人尿液中的α1受体阻滞剂的测定,结果满意。 此外,本文还应用计算化学软件Gaussview3.07和Gaussian03W,采用密度泛函法,在B3LYP/6-31G基组水平上计算了盐酸哌唑嗪的电荷分布,对反应机理和RRS增强的原因进行了讨论。     

Current spreading in GaN-based light-emitting diodes

We have investigated the factors affecting the current spreading length(CSL) in GaN-based light-emitting diodes(LEDs) by deriving theoretical expressions and performing simulations with APSYS.For mesa-structure LEDs,the effects of both indium tin oxide(ITO) and n-GaN are taken into account for the first time,and a new Q factor is introduced to explain the effects of different current flow paths on the CSL.The calculations and simulations show that the CSL can be enhanced by increasing the thickness of the ITO layer and resistivity of the n-GaN layer,or by reducing the resistivity of the ITO layer and thickness of the n-GaN layer.The results provide theoretical support for calculating the CSL clearly and directly.For vertical-structure LEDs,the effects of resistivity and thickness of the CSL on the internal quantum efficiency(IQE) have been analyzed.The theoretical expression relating current density and the parameters(resistivity and thickness)of the CSL is obtained,and the results are then verified by simulation.The IQE under different current injection conditions is discussed.The effects of CSL resistivity play a key role at high current injection,and there is an optimal thickness for the largest IQE only at a low current injection.     

宽光谱AOTF匹配网络对光谱衍射效率影响的研究

基于声光可调滤波器(acousto-optic tunable filter,AOTF)光谱成像分析仪在可见至红外光谱的多个谱区内广泛应用,对AOTF的光谱带宽及衍射效率提出了更高的要求。超声换能器作为AOTF的核心部件,其3 dB工作带宽决定AOTF的光谱衍射范围,故在同一声光介质上制作两片厚度不同的换能器来提高AOTF光谱带宽。由于超声换能器在不同频率下具有不同的输入阻抗,当驱动信号源输出阻抗与超声换能器输入阻抗失配时会产生能量损耗,导致无法把功率最大限度的传递给超声换能器,从而使AOTF光谱衍射效率降低,影响光谱成像清晰度。通过射频电路先进设计系统(ADS)仿真及实验测试,设计了一种新型宽带阻抗匹配网络,在60～200 MHz带宽范围内,阻抗匹配网络功率效率达到90％以上,光谱衍射效率最高达90％,提高了在420～1 150 nm波段内的光谱灵敏度。     

Two-nucleon Excitation from p to sd Shell in 12,14C

The effect of the two-nucleon excitation from p to sd shell is discussed on 12C and 14C in the frame work of the nuclear shell model. The recently suggested shell-model Hamiltonian YSOX provides an suitable tool to investigate the 2 ~! excitation in psd region. Because the strength of the < pp|V |sdsd > interaction, which represents the interaction between the 0 and 2 ~! configurations, is considered in the construction of the Hamiltonian YSOX. The level of 12C is almost independent on the interaction, but excitation energies of certain states in 14C are strongly affected by it. Further investigation shows that the percentage of 2 ~! configuration in these states is quite different from that of the ground state. The non-linear effects of the < pp|V |sdsd > interaction on the configurations and transition rates are also discussed.     

50 keV/u Ne8+与CO转移电离反应中分子轴取向效应测量

利用反应显微成像谱仪,研究了50 keV/u Ne8+碰撞CO转移电离反应中生成的CO2+碎裂过程。通过重构分子离子爆炸碎片C+和O+的三维动量,获得了质心系中CO2+碎裂过程中释放的动能（KER）。在KER谱中发现了来自亚稳态1Σ+,1Π,3Π解离的峰、3Σ+态解离的峰和1Σ_（II）+态解离的峰,同时发现了排斥态3Σ-的贡献。在3Σ-态解离的分子轴取向分布中,首次观测到CO2+解离的分子轴取向效应。The fragmentations of CO2+ are studied in transfer ionization processes of 50 keV/u Ne8+ impact on CO with reaction microscopes. The 3D momenta of C+ and O+ were measured, and the kinetic energy release (KER) of dissociative(CO2+) was obtained accordingly. The peaks resulted from the metastable states of 1Σ+, 1Π and 3Π, of 3Σ+, and of 1Σ(II)+ are identified in KER spectrum. Meanwhile, the repulsive state of 3Σ- was also observed, which forms a broad peak lying between the peaks of 3Σ+ and 1Σ(II)+. In the CO2+ dissociations from 3Σ- state, the orientation effect of CO molecular axis was observed for the first time.     

Electronic structure and magnetic properties of substitutional transition-metal atoms in GaN nanotubes

The electronic structure and magnetic properties of the transition-metal(TM) atoms(Sc–Zn, Pt and Au) doped zigzag GaN single-walled nanotubes(NTs) are investigated using first-principles spin-polarized density functional calculations. Our results show that the bindings of all TM atoms are stable with the binding energy in the range of 6–16 eV. The Sc- and V-doped GaN NTs exhibit a nonmagnetic behavior. The GaN NTs doped with Ti, Mn, Ni, Cu and Pt are antiferromagnetic. On the contrary, the Cr-, Fe-, Co-, Zn- and Au-doped GaN NTs show the ferromagnetic characteristics. The Mn- and Codoped GaN NTs induce the largest local moment of 4μB among these TM atoms. The local magnetic moment is dominated by the contribution from the substitutional TM atom and the N atoms bonded with it.     

用H2O2氧化苯乙烯合成苯甲酸

摘要：以30％H2O2做为氧化剂,钨酸钠与含O双齿有机配体(草酸)形成的络合物为催化剂,在无有机溶剂、无相转移剂的条件下,研究了苯乙烯氧化制苯甲酸的反应。研究结果表明,最佳反应条件为：苯乙烯100．0mmol,n(钨酸钠)：n(草酸)：n(苯乙烯)：n(30％H2O2)=2．0：3．2：100．0：440．0,于92℃反应24h,苯甲酸收率98．6％。用GC—MS跟踪了氧化过程中4种主要物质苯乙烯、1-苯基邻二醇、羟基苯乙酮及苯甲酸含量随反应时间的变化关系,提出了其主要氧化机理为苯乙烯经过环氧化反应、水解生成生成1-苯基邻二醇,1-苯基邻二醇再氧化为羟基苯乙酮、最后氧化为苯甲酸。     

纳米TiO2微柱分离富集测定环境样品中的微量碲

以处理过的纳米TiO2为微柱吸附材料,采用流动注射技术进行微量碲的分离富集,探讨了溶液的pH值、试样流速、试样体积、洗脱液浓度和用量以及干扰离子等因素的影响。 实验结果表明,pH值在8～9.5范围内,纳米TiO2对Te(Ⅳ)具有良好的吸附性能,吸附率接近99%,动态饱和吸附容量为37.02 mg/g;选用2 mL 0.5 mol/L NaOH溶液可将吸附的Te(Ⅳ)完全洗脱,富集倍数为30。 本法的检出限(3σ)为0.013 mg/L,相对标准偏差为RSD=1.99%。 将本法应用于水样的分析,碲的回收率在98%~103%之间,结果令人满意。     

激光诱导击穿谱检测土壤微量铜元素污染研究

理论分析激光诱导击穿光谱(LIBS)的特性,研究谱线信噪比随激光能量和样品属性变化的规律,对土壤样品中的微量Cu元素进行实验测量有重要意义。实验采用的烧蚀激光波长为1 064 nm,脉冲宽度约10 ns,重复率为1 Hz。实验证实背景热辐射和元素特征辐射具有不同的空间变化规律,通过在空间上将两者分离获得较高的信噪比。当激光脉冲能量为40 mJ时,实验采用的土壤样品的最佳测量位置为距离火花中心0.75 mm处,选取Cu 324.75 nm和Cu 327.39 nm作为分析线,对含微量Cu元素土壤样品进行测量。采用内标法对测量结果进行定量分析,得到土壤中Cu元素的检测限可达到67 mg·kg-1,满足国家土壤环境质量标准规定的二级土壤中Cu含量的要求。实验结果表明选择最佳光谱测量位置的方法能够有效提高信噪比,满足土壤中微量Cu污染检测的需求。     

在空气中杀菌灯产生臭氧及其催化分解的研究

用流动型反应装置,对8W杀菌灯(主波长λ=253.7nm)辐照空气时产生的臭氧进行了研究.发现在一定条件下当空气与杀菌灯接触大约7s时,就有超出0.33μg/L的臭氧产生.随着空气流速的减小,产生的臭氧的量随之变大.采用臭氧分解催化剂对臭氧的消除进行了研究,当体积空速小于1.1×10⁵h^-1时,臭氧可以降解到安全范围.