2-取代-4，5-双（α-呋喃基）嗯唑的合成及发光性能的研究

以糠醛为原料,经维生素B1（VB1）催化合成糠偶姻．糠偶姻与不同的酰氯反应生成糠偶姻单酯．糠偶姻单酯在醋酸铵和醋酸作用下合成了新化合物2-取代-4,5-双（α-呋哺基）嗯唑．采用IR,^1H NMR,MS和元素分析对目标产物进行鉴定和表征,证实了其分子结构．并对2-取代-4,5-双（α-呋喃基）嗯唑进行了UV和荧光光谱测定,对其进行了简单的发光性能的研究．     

Radiation resistance property of barium gallo-germanate glass doped by Nb2O5

Effects of Nb₂O₅dopant on the radiation response of barium gallo-germanate(BGG)glass are studied mainly by electron paramagnetic resonance and absorption spectroscopy.Owing to the Nb⁵⁺$Nb³⁺interconversion in doped samples,formations of Ge-related non-bridging oxygen hole center and Ge-related electron center defects after g-ray irradiation are inhibited.Thereby,Nb₂O₅dopant can enhance radiation resistance of BGG glass,and 1.0%Nb2O5 concentration is the best.     

Influences of finite gain bandwidth on pulse propagation in parabolic fiber amplifiers with distributed gain profiles

The evolutions of the pulses propagating in decreasing and increasing gain distributed fiber amplifiers with finite gain bandwidths are investigated by simulations with the nonlinear Schr¨odinger equation. The results show that the parabolic pulse propagations in both the decreasing and the increasing gain amplifiers are restricted by the finite gain bandwidth. For a given input pulse, by choosing a small initial gain coefficient and gain variation rate, the whole gain for the pulse amplification limited by the gain bandwidth may be higher, which is helpful for the enhancement of the output linearly chirped pulse energy. Compared to the decreasing gain distributed fiber amplifier, the increasing gain distributed amplifier may be more conducive to suppress the pulse spectral broadening and increase the critical amplifier length for achieving a larger output linearly chirped pulse energy.     

静电纺In2O3纳米纤维的光致发光性能研究

利用静电纺丝技术结合高温煅烧方法制备了一系列多孔结构的一维In2O3无机纳米纤维,并探讨了煅烧温度对产物发光性能的影响及其发光机理.利用热重仪(TGA)、X射线衍射仪(XRD)、傅里叶红外光谱仪(FT-IR)、扫描电子显微镜(SEM)分析了产物的热分解情况、晶型、组分和形貌;通过紫外-可见光谱仪和荧光分光光度计分析研究了一维In2O3纳米纤维的光吸收性能和光致发光性能.结果表明:静电纺前驱体复合纳米纤维成型良好,经500℃、600℃、700℃、800℃高温煅烧后仍保持纤维结构,但纤维直径明显减小,当煅烧温度达到800℃时,纤维出现中空结构;不同温度下煅烧所得In2O3均为立方铁锰矿型;随着煅烧温度的升高,In2O3纳米颗粒粒径逐渐增大;In2O3纳米纤维的的最大紫外吸收峰位于300nm左右;在室温下,In2O3纳米纤维经274nm光激发后在553 nm处出现较强的绿光发射峰.     

Influences of finite gain bandwidth on pulse propagating in parabolic fiber amplifiers with distributed gain profiles

The evolutions of the pulses propagating in decreasing and increasing gain distributed fiber amplifiers with finite gain bandwidths are investigated by simulating with the nonlinear Schrödinger equation. The results show that the parabolic pulse propagations in both the decreasing and the increasing gain amplifiers are restricted by the finite gain bandwidth. For a given input pulse, by choosing small initial gain coefficient and gain variation rate, the whole gain for the pulse amplification limited by the gain bandwidth may be higher, which is helpful to the enhancement of the output linearly chirped pulse energy. Compared to the decreasing gain distributed fiber amplifier, the increasing gain distributed amplifier may be more conducive to suppress the pulse spectral broadening and increase the critical amplifier length for achieving a larger output linearly chirped pulse energy.     

60Co γ-射线辐照对肖特基二极管1/f噪声的影响

在肖特基二极管(Schottky barrier diode,SBD)辐照损伤机理和总剂量效应分析的基础上,利用1/f噪声的迁移率涨落和载流子数涨落模型,深入研究辐照损伤对器件1/f噪声的影响. 研究结果表明,辐照诱生新的界面态,改变界面态密度分布,进而调制了肖特基势垒高度,增大表面复合速度是引起器件性能退化主要原因,也是1/f噪声剧烈增加的主要原因. 正因为如此,噪声与器件退化存在相关性,即噪声拟合参数B越大,偏离标准值越多,器件可靠性越差,抗辐照 关键词： 肖特基二极管 f噪声')" href="#">1/f噪声 60Co γ射线')" href="#">⁶⁰Co γ射线 界面态     

高压密闭消解-钼蓝分光光度法测定钴铬烤瓷合金中硅

在HNO3-HCl-HF混酸中高压密闭消解,采用钼蓝分光光度法测定钴铬烤瓷合金中的硅量。研究了酸体系、消解时间及共存离子对硅测定的影响。方法用于已知样品的测定,相对标准偏差小于3%(n=11),加标回收率为98.9%~101%。方法精密度高、准确度好,能够满足钴铬烤瓷合金中硅含量测定的要求。     

汽轮机小长径比静叶片的优化径向积叠

应用粘性流动数值计算对叶轮机械叶片进行设计，能够使设计者对几种不同设计方案进行分析以满足设计要求，并获得最佳设计方案．本文采用三维N．S方程组和Baldwin-Lomax湍流模型，对一个小长径比的汽轮机导叶进行三维粘性流场数值模拟．计算结果表明，采用合适的周向弯曲（优化径向积叠）同样可以提高短叶片的效率．本计算方法可用来分析和研究叶片径向积叠形式对径向和周向流量平均绝热效率的影响，以获得较优的积叠形式．     

相对论σ–ω模型中负能海的贡献

在考虑负能海的情况下,运用σ－ω模型,得到了核物质的饱和曲线和好的不可压缩系数,引入形状因子处理了发散积分,仔细研究了ω介子引起的接触相互作用的影响,计算了核基态平均每核子的剩余介子数.     

神光-Ⅲ主机装置成功实现60TW/180kJ三倍频激光输出北大核心CSCD

2015年9月15日,由中国工程物理研究院激光聚变研究中心承担研制的神光-Ⅲ主机装置成功完成了48束激光三倍频180kJ/3ns、峰值功率60TW的输出测试实验,标志着神光-Ⅲ主机装置已全面建成并达到设计指标,成为现有输出能力世界排名第二、亚洲排名第一的惯性约束聚变激光驱动器。