近场拉曼光谱在纳米结构表征中的应用

近场拉曼光谱是近场光学领域中的新型技术,因其可对纳米结构进行光谱表征而备受科学研究者的关注。 文章从光学的角度简述了将近场光学与拉曼光谱相结合成为近场拉曼光谱的原理,介绍了近场拉曼光谱技术的优势,详细阐述了近场拉曼光谱在单壁碳纳米管、生物样品、热电晶体、染料分子等纳米结构表征中的应用,展现了近场拉曼光谱技术广阔的应用前景。     

现行日本高中化学教材插图特点分析及启示*

日本数研出版(2018年版)的高中化学教材在插图设计方面有许多独到之处,实现了从“教材”向“学材”转变的插图设计理念。综合现有对教材插图科学性的研究,采用文本分析法从图文排版、插图的表现形式、图文融合程度、插图素材选取以及用插图进行多维度信息整合等5个维度对书中插图进行分析,并对我国教材插图的编写提供参考性意见。     

同步相移数字全息综述(特邀)

相移数字全息技术将相移技术与数字全息技术相结合,为微观物体的三维形貌和折射率分布检测提供了一种快速、无损、高精度手段.与离轴数字全息相比,相移数字全息采用同轴光路,可以充分利用CCD相机的空间带宽积.然而,传统相移数字全息需要依次记录多幅不同相移量全息图,才能消除零级像和共轭像,再现出无混叠的相位/振幅图像.同步相移又...     

Polarization readout analysis for multilevel phase change recording by crystallization degree modulation

Four different states of Si15Sb85 and Ge2Sb2Te5 phase change memory thin films are obtained by crystallization degree modulation through laser initialization at different powers or annealing at different temperatures. The polarization characteristics of these two four-level phase change recording media are analyzed systematically. A simple and effective readout scheme is then proposed, and the readout signal is numerically simulated. The results show that a high-contrast polarization readout can be obtained in an extensive wavelength range for the four-level phase change recording media using common phase change materials. This study will help in-depth understanding of the physical mechanisms and provide technical approaches to multilevel phase change recording.     

Read-only memory disk with AgO_x super-resolution mask layer

A novel read-only memory (ROM) disk with an AgOx mask layer was proposed and studied in this letter. The AgOx films sputtered on the prernastered substrates, with pits depth of 50 nm and pits length of 380 nm, were studied by an atomic force microscopy. The transmittances of these AgOx films were also measured by a spectrophotometer. Disk measurement was carried out by a dynamic setup with a laser wavelength of 632.8 nm and a lens numerical aperture (NA) of 0.40. The readout resolution limit of this setup was λ/(4NA) (400 nm). Results showed that the super-resolution readout happened only when the oxygen flow ratios were at suitable values for these disks. The best super-resolution performance was achieved at the oxygen flow ratio of 0.5 with the smoothest film surface. The super-resolution readout mechanism of these ROM disks was analyzed as well.     

Experimental study on multiphoton ionization of Ar with high intensity short laser pulses

<正>We present high resolution photoelectron energy spectra from multiphoton ionization(MPI) of Ar subject to laser pulses with wavelength of 400 nm,pulse duration of 35 fs,and maximum intensity of 5×10~(13) W/cm~2.Ionizations into Ar~+ ~2P_(3/2) and ~2P_(1/2) channels are observed and distinct resonance structures are found in both ionization channels.The intensity dependence of the resonance structures is explained in terms of the mechanism of Freeman resonance,i.e.,transient resonances of alternating current (AC) Stark-shifted Rydberg states at specific intensities within the laser pulse.     

超级微波消解电感耦合等离子体质谱法测定车用陶瓷催化剂中铂、钯、铑

建立了一种检测车用陶瓷催化剂中铂、钯、铑的超级微波消解电感耦合等离子体质谱法.通过单因素试验和正交试验优化酸配比、称样量、消解温度、消解时间及回流溶剂参数,确定了最佳消解方法:0.1 g样品中加入1 mL盐酸、5 mL硝酸、1 mL氢氟酸,在220℃的消解温度下保持30 min,赶酸后加入10 mL逆王水于170℃回流...     

火焰热解法生长定向碳纳米管

本文研究了火焰热解法的碳纳米管制备实验(催化剂为Fe/Mo/Al2O3),发现在火焰热解法条件下碳纳米管阵列可在火焰热解腔中定向生长,产物较为整齐,碳管形态较好.本课题组之前在电场作用下采用Fe(CO)5为催化剂,在V型体火焰中亦可制得碳纳米管阵列,对比两者发现热解腔内制得阵列碳纳米管长度较长,定向性更优;而电场作用下的V型体火焰中制得阵列中的碳纳米管较直.进而,在火焰热解法制备中施加电场,发现随电压增加,碳纳米管阵列更直,碳管长度和产量明显增长.     

镱钠共掺氟化钙锶混晶近红外光谱与激光参数

研究了15％Yb,20％Na:CaF2-SrF2混晶(Yb,Na:CaF2-SrF2,CaF2:SrF2=1:1)的近红外光谱和激光参数特性.研究显示,Yb,Na:CaF2-SrF2混晶在974 nm处吸收带宽为22 nm,吸收系数为13.09 cm-1,吸收截面为0.31×10-20 cm2.Yb3+离子在CaF2-...     

Cr掺杂的丙烷选择氧化制丙烯酸高效催化剂

在丙烷选择氧化制丙烯酸催化剂MoVTeNbOx的活性相M1基础上掺杂一定量的Cr,当Cr/Nb摩尔比为0.002时,催化剂具有很高的丙烯酸选择性(78.3%)和收率(50.7%);并采用X射线衍射、X射线光电子能谱、程序升温还原、O2程序升温脱附、NH3程序升温脱附和异丙醇氧化等手段对催化剂的构效关系进行了探讨.结果表明,适量Cr的添加可调节催化剂表面Mo6+,V5+和Te4+等物种含量,提高催化剂的氧化能力,使丙烷转化率增加.同时,适量Cr的添加使得催化剂表面酸强度下降,酸性位点数量减少,从而抑制丙烯酸的深度氧化,提高了丙烯酸选择性.