一种具有深度值的莫尔轮廓图

提出一种具有深度值的莫尔轮廓图。将一称为高标的正圆锥与被测物一起置于粗光栅之后 ,平行光照明 ,远场拍照。在所拍图片上高标的高度值 (已知 )除以高标上的等高线数即可求得相邻等高线的深度值 ,进而直接在莫尔轮廓图上读出任一点到基准点的深度差值     

LIE ALGEBRA K$(n,\mu _j,m)$ OF CARTAN TYPE OF CHARACTERISTIC p=2

Let $K(n,\mu _j,m),n=2r+1$,denote the Lie algebra of characteristic p=2,which is defined in [4].In the paper the restrictability of $K(n,\mu _j,m)$ is discussed and it is proved that,when $r\equiv 1(mod 2)$ and $r>1,I(ad f)=n+1$ if and only if $0\neq f \in $. Then the invariance of some filtrations of K(n,\mu,m) and the condition of isomorphism of K(n,\mu _i,m) and K(n',\mu _j ^',m') are obtained.Besides,the generators and the derivation algebra of K(n,\mu _i,m) are discussed.The results also hold,when $r\equiv 0 (mod 2)$ and r>0.     

白色荧光粉CaF2∶Yb3+/Eu3+/La3+的制备及其上转换发光特性

采用改进的两步高温固相熔融法制备了Yb^3+、Eu^3+、La^3+共掺杂CaF 2的上转换荧光粉。基于荧光猝灭原理,通过改变La^3+掺杂浓度来调节CaF 2∶Yb^3+/Eu^3+材料的发光性能,并在980 nm近红外光激发下,获得了该材料的白色上转换发光(UCL)。在该发光体系中,Yb^3+不仅起到了敏化Eu^3+的作用,同时,Yb^3+二聚体(Yb^3+-dimer)自身合作发出波长范围480~540 nm的绿色荧光。而白光三基色中的绿光正是来自Yb^3+二聚体的合作发光。Eu^3+则作为激活剂,同时发出红色和蓝色荧光。荧光寿命测试结果表明Yb^3+-dimer与Eu^3+之间存在有效的能量传递。值得注意的是,在980 nm激光激发下,1%La^3+掺杂的样品表现出最佳的红、绿、蓝三基色光比列,实现了材料的上转换白光发射,其色度坐标为(0.311,0.340)。     

高频单线圈双调谐NMR单晶探头的研制

本文报道了一种测角单晶NMR探头。该探头采用单线圃双调谐电路,工作频率在90MHz-110 MHz连续可调,可进行交叉极化大功率去耦实验。文中提出了一种简单而有效的测角装置,可使单晶绕三个互相垂直轴转动实现单晶的NMR测量。作为典型的应用例子,本文利用该探头实现了单晶DGO(2NH₂CH₂COOH·H₂C₂O₄)屏蔽张量的测量。     

The research on suspended ZnO nanowire field-effect transistor

This paper reports that a novel type of suspended ZnO nanowire field-effect transistors (FETs) were successfully fabricated using a photolithography process, and their electrical properties were characterized by I--V measurements. Single-crystalline ZnO nanowires were synthesized by a hydrothermal method, they were used as a suspended ZnO nanowire channel of back-gate field-effect transistors (FET). The fabricated suspended nanowire FETs showed a p-channel depletion mode, exhibited high on--off current ratio of ～10⁵. When V_DS=2.5 V, the peak transconductances of the suspended FETs were 0.396 μS, the oxide capacitance was found to be 1.547 fF, the pinch-off voltage V_TH was about 0.6 V, the electron mobility was on average 50.17 cm²/Vs. The resistivity of the ZnO nanowire channel was estimated to be 0.96× 10²Ω cm at V_GS = 0 V. These characteristics revealed that the suspended nanowire FET fabricated by the photolithography process had excellent performance. Better contacts between the ZnO nanowire and metal electrodes could be improved through annealing and metal deposition using a focused ion beam.     

基于改进型阿特伍德机的重力加速度测量

阿特伍德机是用于测量加速度和验证运动定律的力学实验装置.本文通过增加滑轮组提高系统在实验中的稳定性,增加运动控制装置消除在改变小质量时的初速度的不良影响,通过等加速度方程对加速度求解的,并通过对实验过程的考虑以及对数据的处理方法的选择,同时我们对空气阻力以及滑轮转动惯量计算的修正方法,通过PASCO测量系统测得到精确的...     

钙钛矿/硅异质结叠层太阳电池:光学模拟的研究进展

近几年,钙钛矿/硅异质结叠层太阳电池发展迅速,效率已经从13.7％提升到29.1％.由于叠层电池器件的制作工艺复杂,而叠层太阳电池中的光学损失对转换效率的影响很大,所以通过光学模拟进而获得高效电池至关重要.本文首先从商业软件和自建模型两方面概述了光学模拟的方法,接着从反射损失和寄生吸收两方面针对光学模拟研究进展进行了总...     

硅基薄膜太阳电池一维光子晶体背反射器的模拟设计与制备

从模拟和实验两个方面研究了一种适用于硅基薄膜太阳电池的一维光子晶体新型背反射器.首先采用时域有限差分方法,模拟研究了组成一维光子晶体的两种介质的折射率比、厚度比以及周期厚度对光子禁带的影响.基于模拟结果,制备出一种由低折射率SiOx层与高折射率非晶硅a-Si层周期性交叠构成的禁带可调式一维光子晶体背反射器.通过改变a-Si层的厚度,使得禁带范围由500—750 nm波长范围红移至650—1100 nm,反射率分别达到96.4%和99%.将上述结构的一维光子晶体作为背反射器分别应用于非晶硅单结太阳电池和非晶硅/微晶硅双结叠层太阳电池,与没有背反射结构电池相比,短路电流密度分别提升了18.3%和15.2%.同时模拟研究了在不同入射角度下自然光、TE波和TM波对光子晶体反射特性的影响.研究结果表明,在太阳电池中,光线倾斜入射对一维光子晶体反射率的影响有限.     

太阳模拟器中椭球面聚光镜参数的确定

椭球面聚光镜是太阳模拟器设备的重要组成部分,其能量收集的效率决定着太阳模拟系统的能量传递效率,而太阳模拟器光学系统中的椭球面聚光镜参数一直没有理论上的设计依据,结合氙灯的发光特性并通过对MATLAB 中建立的椭球面聚光镜聚光过程数值分析模型给出了椭球面聚光镜包括第一焦距、最大成像放大倍率、包容角范围及前后开口直径的确定依据,并通过在Lighttools 中建立的4种仿真模型验证了理论分析的正确性。第一焦距由光源光中心高确定,最大成像放大倍率由光学积分器相对孔径及椭球镜包容角范围共同确定,椭球镜包容角范围不小于30°～120°,前开直径口由椭球镜的最大孔径角确定,后开口直径由最小孔径角和光源的径向调节量共同确定。该结论给椭球面聚光镜的设计提供了理论支撑,有利于设计完成高能量收集效率的椭球面聚光镜。     

Anisotropic Transport on Monolayer and Multilayer Phosphorene in the Presence of an Electric Field

We demonstrate theoretically the anisotropic quantum transport of electrons through an electric field on monolayer and multilayer phosphorene. Using the long-wavelength Hamiltonian with continuum approximation, we find that the transmission probability for transport through an electric field is an oscillating function of incident angle, electric field intensity, as well as the incident energy of electrons. By tuning the electric field intensity and incident angle, the channels can be transited from opaque to transparent. The conductance through the quantum waveguides depends sensitively on the transport direction because of the anisotropic effective mass, and the anisotropy of the conductance can be tuned by the electric field intensity and the number of layers. These behaviors provide us an efficient way to control the transport of phosphorene-based microstructures.