机载腔增强吸收光谱系统应用于大气NO_2空间高时间分辨率测量

介绍了一套用于机载平台测量的非相干宽带腔增强吸收光谱(IBBCEAS)系统,并应用于实际大气NO_2空间分布的高时间分辨率观测.为满足机载测量中对时间分辨率的需求,系统采用离轴抛物面镜代替消色差透镜提高光学耦合效率;并运用Allan方差,对系统性能进行了分析.通过腔增强吸收光谱系统与长光程吸收光谱系统对实际大气NO_2的对比测试,两者线性相关系数R~2达到0.86.将IBBCEAS系统应用于机载平台,在时间分辨率为2 s的情况下,探测限达到95 ppt(1σ).通过机载观测,获得了华北地区石家庄等地上空对流层大气NO_2的廓线信息.     

Theoretical studies on structure and performance of [1,2,5]‐oxadiazolo‐[3,4‐d]‐pyridazine‐based derivatives

Based on energetic compound [1,2,5]‐oxadiazolo‐[3,4‐d]‐pyridazine, a series of functionalized derivatives were designed and first reported. Afterwards, the relationship between their structure and performance was systematically explored by density functional theory at B3LYP/6‐311 g (d, p) level. Results show that the bond dissociation energies of the weakest bond (N–O bond) vary from 157.530 to 189.411 kJ · mol^?1. The bond dissociation energies of these compounds are superior to that of HMX (N–NO_2, 154.905 kJ · mol^?1). In addition, H1, H2, H4, I2, I3, C1, C2, and D1 possess high density (1.818–1.997 g · cm^?3) and good detonation performance (detonation velocities, 8.29–9.46 km · s^?1; detonation pressures, 30.87–42.12 GPa), which may be potential explosives compared with RDX (8.81 km · s^?1, 34.47 GPa ) and HMX (9.19 km · s^?1, 38.45 GPa). Finally, allowing for the explosive performance and molecular stability, three compounds may be suggested as good potential candidates for high‐energy density materials. Copyright © 2016 John Wiley & Sons, Ltd.     

掺磷TiO_2优化TiO_2/MBA/Ag三明治结构的SERS性能

本文以磷酸为磷源,通过溶胶水热法制备磷掺杂TiO_2,利用Lee和Meisel的方法制备银溶胶,以4-巯基苯甲酸(MBA)为探针分子,通过构建TiO_2/MBA/Ag三明治结构,研究磷掺杂二氧化钛对该基底表面增强拉曼(SERS)性能的提升。通过TEM、XRD、XPS、DRS和拉曼光谱图表征二氧化钛的形貌结构、化学组成、光学和拉曼性能,结果表明,制备出的磷掺杂二氧化钛为锐钛矿型纳米颗粒,粒径范围6~12nm,XPS显示磷以P~(5+)替代了Ti~(4+),形成O-P-O键掺入TiO_2的晶格中,当磷的掺杂量在1.77%时,TiO_2/MBA/Ag三明治体系具有最佳的SERS信号,这是因为适量的磷掺杂降低了TiO_2的能带间隙,丰富TiO_2的表面态,这能促进TiO_2向MBA分子的电荷转移。     

The way to high-performance single nanowire photodetectors: problems and prospects

<正>As potential building blocks for micro-nano devices,one-dimensional semiconductor nanowires(NWs)have been widely studied in recent decades.Due to limited dimension and large surface-to-volume ratio,devices based on NWs are more likely to exhibit unique properties.NW photodetectors adopting different materials have been fabricated.However,the performance is greatly affected by several issues such as lattice quality,surface homogeneity,contact electrodes and     

针对调频引信的窄带扫频式干扰优化方法

扫频式干扰是调频体制引信的主要威胁之一,但其干扰效果具有一定随机性。为了提高其干扰效率,在理论分析扫频式干扰作用下调频引信失效机理的基础上,提出了一种针对单通道调频多普勒引信的窄带扫频式干扰优化方法,可以获取最优的扫频频率步进点数,并依此进行非等间隔频率步进的窄带扫频式干扰。仿真与实测结果表明,该方法可以提高扫频式干扰的干扰效率,同时该方法也可以为成功干扰采用多通道等抗干扰措施的调频引信提供理论设计依据。     

20Mgβ衰变谱学与15O(α,γ)19Ne反应(英文)

15O（α,γ）19Ne（p,γ）20Na反应链是高温CNO循环向快速质子俘获过程突破的一条关键路径,相关的反应率输入量可通过20Mg的β衰变可布居19Ne共振态并测量其衰变性质来获得。通过高效率高精度地测量20Mg β衰变中产生的质子与γ射线得到了20Mg衰变的详细信息,并构建了完整的衰变纲图,还进行了19Ne 4 033 keV共振态衰变性质的探索,获得了该态在20Mg β衰变中被布居的分支比上限。通过比20Mg和20O镜像能级跃迁的结果确认了同位旋非对称性,为检验相关理论模型提供了精确的实验数据。对于突破路径中有重要影响的19Ne 4 033 keV共振态的性质,有待更高统计的实验进一步研究。The breakout from the hot CNO cycle to the rapid proton capture process can occur via the 15O(α,γ)19Ne(p,γ)20Na reaction sequence, and the β decay of 20Mg can be used as an alternative method to characterize some specific resonances, which will provide detailed nuclear structure input for reaction rate calculations. The reliable information on the decay properties and structure of 20Mg was obtained by measuring the emitted particles and γ-rays in the β decay with high efficiency and high resolution. Attempt was also made to search for the decay channels associated with the 4 033 keV resonance in 19Ne. To test fundamental symmetries, the transitions in the mirror decays of 20Mg and 20O were compared. The precise experimental data presented here would be important to constrain the theoretical calculations. It is desirable to clarify the astrophysically relevant problem by further experiments with improved statistics on the basis of the present work.     

Mössbauer study of α-Fe2O3 fine particles coated with cobalt and pyridine

The properties of α-Fe₂O₃ line particles coated with cobalt and pyridine have been investigated by means of magnetic measurements and Mössbauer spectra. The Morin transition temperature, T_M for Co-coated α-Fe₂O₃ decreases and that for pyridine-coated α-Fe₂O₃ increases, comparing with the pure α-Fe₂O₃. The angles between (111) axis and the spin of iron ions for these samples have been calculated from the quadrupole splitting.     

含椭球包体多相复合介质电导率的有效介质理论

本文应用有效介质理论(EMT),研究含椭球包体的多相复合介质中的导电性。建议用各向异性因子m估计非均匀系统的局域各向异性,并给出一个计算此情况下有效电导率张量的公式。对于椭球包体取向完全无序的介质,建议以介质的几何结构因子I_i(i=χ,y,z)估计组成包体的颗粒之间的近场效应。研究表明,结构因子I_i与包体的退极化因子n_i(i=χ,y,z)之间存在简单的关系。EMT的计算结果表明,抻长的椭球包体(b/α≈0.2)和压扁的椭球包体((b/α≈7—8)是导致渗流阈值对c₁^*=0.17的两种主要几何结构。初步的理论分析表明,由这两种几何形状产生渗流的共同机制是在介质中形成“无穷”长的链状集团。     

“海纹石”的矿物学及谱学特征研究

“海纹石”是具有蓝色条带的针钠钙石,是一种稀有的宝石材料,具有较好的市场前景。为查明其矿物学特征及成因,采用常规宝石学测试并结合X射线衍射(XRD)、傅里叶红外吸收光谱(FTIR)、拉曼光谱(Raman)、扫描电镜(SEM)及紫外-可见分光光度计(UV-Vis)等现代测试方法,对“海纹石”不同颜色部分的矿物成分及特征进行了深入分析。XRD,FTIR,Raman分析结果表明,“海纹石”的主要组成矿物为针钠钙石,并含有少量的方解石,与SEM分析结果较为一致。FTIR分析显示,“海纹石”白色部分在1 500 cm-1处出现一个明显的宽吸收带并伴有883和710 cm-1的吸收峰,表明含有少量方解石,而蓝色部分在该处没有此吸收。紫外可见吸收光谱分析显示蓝色部分在可见光区有640 nm宽吸收峰,表明可能含有微量元素Cu。“海纹石”白色和蓝色部分矿物组分的差异,表明两者可能形成于不同的地质环境。     

3 GPa熔融盐固体介质三轴高温压力容器的轴压摩擦力标定

 在温度标定和围压标定的基础上,采用轴压循环方法,对3 GPa固体介质三轴高温高压实验系统的轴压摩擦力进行了标定,分析了围压、温度、轴向位移速率、装样方式（盐套类型）等实验条件对轴压摩擦力的影响。结果表明：静摩擦力、挤压摩擦力和滑动摩擦力3种轴压摩擦力对轴向应力的影响不同,其中静摩擦力和挤压摩擦力对轴向应力的影响很小,影响应力精度的主要是滑动摩擦力。静摩擦力及滑动摩擦力与围压正相关;静摩擦力与轴向位移速率正相关,但受其影响较小,滑动摩擦力不受其影响;静摩擦力和滑动摩擦力与温度负相关,并且受其影响较显著;盐套类型对轴压摩擦力的影响较大,当实验条件接近盐套熔点时,轴压摩擦力显著降低,当样品周围的盐套处于熔融状态时,轴压摩擦力最小。基于此,确定了标定轴压摩擦力的具体步骤,并对角闪岩的应力-应变曲线进行了轴压摩擦力标定。对比轴压摩擦力校正前、后的应力-应变曲线发现,经过轴压摩擦力校正的应力-应变曲线能更好地反映样品的实际变形情况。