带间级联激光器电子注入区优化研究(特邀)

带间级联激光器有源区内部的物理机制复杂,尚未得到充分研究.优化了电子注入区结构,通过减小InAs/AlSb啁啾超晶格中InAs量子阱的厚度促进电子向光增益区的注入,在较低的电子注入区掺杂浓度下满足了光增益区电子数和空穴数基本相等的注入平衡条件,降低了有源区中自由载流子吸收和杂质散射造成的光损耗.采用该有源区结构的带间级...     

铜催化的多组分反应合成二芳基炔丙胺类衍生物

以醛、苯乙炔和二芳胺为原料, 三组分一锅法合成了一系列二芳基炔丙胺类化合物. 产物的结构通过1H NMR, 13C NMR和HRMS证实.     

Magnetic and electric properties of transition-metal doped wurtzite CdSe from first-principles calculation

s The geometrical structures of Cd0.75TM0.25Se （TM = Ti, V, Cr and Mn） are optimized, and then their electric and magnetic properties are investigated by performing first-principles calculations within the generalized gradient approximation for the exchange-correlation function based on density functional theory. Cd0.75TM0.25Se （TM =Ti and V） are found to have high spin-polarization near 100% at the Fermi level. Cd0.75TM0.25Se （TM = Cr and Mn） are half-metallic ferromagnets whose spin-polarization at the Fermi level is absolutely ＋100%. The supercell magnetic moments of Cd0.75Cr0.25Se and Cdo.75Mno.25Se are 4.00 and 5.00 μB, which arise mainly from Cr-ions and Mnions, respectively. The half-metallicity of Cdo.75Cro.25Se is more stable than that of Cd0.75Mn0.25Se. The electronic structures of Cr-ions and Mn-ions are Cr eg2↑t22g↑ and Mn e2 3 ↑t23g↑, respectively.     

Strain-Compensated InGaAs/InAlAs Quantum Cascade Detector of 4.5 μm Operating at Room Temperature

We present a strain-compensated InP-based InGaAs/InAlAs photovoltaic quantum cascade detector grown by solid source molecular beam epitaxy. The detector is based on a vertical intersubband transition and electron transfer on a cascade of quantum levels which is designed to provide longitudinal optical phonon extraction stairs. By careful structure design and growth, the whole epilayer has a residual strain toward InP substrate of only -2.8× 10^-4. A clear narrow band detection spectrum centered at 4.5 μm has been observed above room temperature for a device with 200／times 200 ×μm^2 square mesa.     

介质条件对玻璃表面吸附溶液中~(241)Am(Ⅲ)的影响

在放化分析中,容器器壁对镅的吸附损失较为严重[1-3]。为了查明玻璃器表面吸附241Am(Ⅲ)的影响因素,寻找减小或避免镅在器壁上吸附损失的方法,以及为今后探讨镅在容器壁上的化学行为提供实验依据,本文用玻璃微球模拟玻璃器壁,研究了不同溶液介质条件下玻璃表面对241Am(Ⅲ)的吸附。1实验部分1·1主要试剂和仪器241Am母液,α放射性活度为6471Bq /mL,自制;普通硬质玻璃微球(比表面为15·07m2/g),四川省江油金圆玻璃珠有限公司生产;其余试剂均为市售分析纯。雷磁牌PHB—4PH计, E—201—C,上海精密科学仪器有限公司;电子分析天平, TG3288,…     

用宇宙线大气簇射Ne-Nμ关系研究“膝”区原初成分

用梁王山宇宙线观测站获得的宇宙线大气簇射μ子数据, 与假设原初分别为质子、氦核、中等核(Z=15)和铁核的Monte-Carlo模拟结果进行比较, 结果显示宇宙线膝区原初成分无明显变化且以轻核为主.     

宇宙线大气簇射μ子定点密度及原初能谱“膝”的研究

用梁王山宇宙线观测站的数据研究宇宙线大气簇射μ子定点密度谱,谱呈现明显的拐折.通过MonteCarlo模拟,得到拐点对应的能量约为1.7×10¹⁵eV,拐点前后原初能谱指数差约为0.43,证实了KASCADE实验μ子定点密度谱呈现拐折的首次观测结果,又一次推证了原初宇宙线能谱膝的存在.     

面向谐振式微光学陀螺应用的球形谐振腔DQ乘积优化

基于谐振式光学陀螺高灵敏度、低成本与微型化的发展需求, 为了实现高灵敏度的谐振式微光机电陀螺, 提出了以集成光学微谐振腔领域里高Q值、大直径谐振腔的制作为目标, 应用方向为谐振式光学陀螺的球形光学微谐振腔核心敏感单元. 在实验中以氢火焰作为热源采用熔融法制备球形光学微谐振腔. 通过调节氢气的流量控制氢火焰热源面积, 制备了不同直径(300-2200 μm)的球形谐振腔, 分析了球形谐振腔Q 值、DQ乘积、陀螺灵敏度与谐振腔直径D的对应关系及其原因, 获得了最优参数的面向谐振式光学陀螺的球形谐振腔敏感单元. D=1260 μm时, 球腔品质因数 Q=7.18×10⁷, 得到的最优陀螺灵敏度约为10°/h, 满足商业级应用的需求, 为芯片级、高精度、低成本的新型谐振式光学微腔陀螺的研究奠定了实验基础.     

Cu-Ni双金属催化剂催化脂肪伯醇脱氢制备醛

脂肪伯醇催化转化制备相应的醛是具有挑战性的课题,目前多采用负载的单金属铜基催化剂.本文报道了双金属催化剂Cu-Ni/γ-Al2O3催化3,3-二甲基-1-丁醇脱氢制备相应的醛,在相同反应条件下,Cu-Ni/γ-Al2O3比单金属催化剂Cu/γ-Al2O表现出更高的催化活性,能将一系列脂肪伯醇高选择性转化为相应的醛.     

Theoretical Study on Electronic and Charge Transfer Properties of Oligo[8]thiophene and Its Circular,Hooped, and Helical Derivatives

The novel linear, circular, hooped, and helical molecules based on oligo[8]thio- phene were theoretically studied for the applications of charge transfer devices. To investigate the influence of topology for oligo[8]thiophene derivatives, the geometry structures, frontier molecular orbital （FMO） energies, charge transport properties, and stability property were predicted by density functional theory methods. The calculated results reported herein show that the oligo[8]thiophene derivative with linear structure has smaller energy gap, and fused oligo[8]thiophene derivative with circular structure has the smallest reorganization energy among the designed molecules. We have also studied the stability properties of the designed molecules, and oligo[8]thiophene derivatives are more stable tharJ the fused oligo[8]thiophene derivatives.