球解码的改进算法

文中首先对MIMO系统启发式算法中的BLAST算法和球解码(CL算法)进行了研究.然后,在前面介绍的相关知识基础上,提出了一种新的球解码算法.该改进算结合BLAST算法计算量小和球解码算法(CL算法)误码性能好的优点而提出的.改进算法在牺牲一定误码性能的情况下,换取算法计算量的大幅度下降.仿真结果表明了这种改进算法的有效性.     

CdS Quantum Dots Encapsulated in Chiral Nematic Mesoporous Silica: New Iridescent and Luminescent Materials

Simultaneous integration of light emission and iridescence into a semiconducting photonic material is attractive for the design of new optical devices. Here, a straightforward, one‐pot approach for liquid crystal self‐assembly of semiconductor quantum dots into cellulose nanocrystal‐templated silica is developed. Through a careful balance of the intermolecular interactions between a lyotropic tetraalkoxysilane/cellulose nanocrystal dispersion and water‐soluble polyacrylic acid/mercaptopropionic acid‐stabilized CdS quantum dots, CdS/silica/nanocellulose composites that retain both chiral nematic order of the cellulose nanocrystals and emission of the quantum dots are successfully co‐assembled. Subsequent removal of the cellulose template and organic stabilizers in the composites by controlled calcination generates new freestanding iridescent, luminescent chiral nematic mesoporous silica‐encapsulated CdS films. The pores of these materials are accessible to analytes and, consequently, the CdS quantum dots undergo strong luminescence quenching when exposed to TNT solutions or vapor.     

Si掺杂的AlGaInP/GaInP多量子阱光学特性

低压MOCVD方法生长了掺Si与不掺Si的AlGaInP/GaInP多量子阱结构,运用X射线双晶衍射与光荧光技术研究了掺Si对量子阱性能的影响.测试结果表明掺Si使量子阱的生长速度增加,掺Si量子阱的光荧光强度比未掺Si量子阱的光荧光强度改善了一个数量级.     

9μm截止波长128×128 AlGaAs/GaAs量子阱红外焦平面探测器阵列

报道了128×128 AlGaAs/GaAs量子阱红外焦平面探测器阵列的设计和制作.采用金属有机化学气相淀积外延技术生长外延材料,并在GaAs集成电路工艺线上完成工艺制作.为得到器件参数,设计制作了台面尺寸为300μm×300μm的大面积测试器件;77K下2V偏压时暗电流密度为1.5×10-3A/cm2;80K工作温度下,器件峰值响应波长为8.4μm,截止波长为9μm,黑体探测率DB 为3.95×108(cm·Hz1/2)/W.将128×128元 AlGaAs/GaAs量子阱红外焦平面探测器阵列芯片与相关CMOS读出电路芯片倒装焊互连,在80K工作温度下实现了室温环境目标的红外热成像,盲元率小于1%.     

磁场中准二维强耦合磁极化子的性质

采用线性组合算符和改进的LLP变分法,研究了磁场中无限势垒量子阱内电子与界面光学声子强耦合、与体纵光学声子弱耦合系统的基态,得到了磁极化子的振动频率和自陷能随量子阱宽和磁场变化的规律.对CdF2/AgCl量子阱进行了数值计算,结果表明,磁极化子的振动频率和自陷能随阱宽的增加而减小,随磁场的增加而增大,但不同支声子与电子和磁场相互作用对磁极化子的振动频率和自陷能的贡献大不相同.此外,对以上现象进行了分析和解释.     

基于MOCVD技术的长波AlGaAs/GaAs量子阱红外焦平面探测器

采用n型掺杂背面入射AlGaAs/GaAs量子阱结构,用MOCVD外延生长和GaAs集成电路工艺,设计制作了大面积AlGaAs/GaAs QWIP单元测试器件和128×128、128×160、256×256 AlGaAs/GaAs QWIP焦平面探测器阵列。 用液氮温度下的暗电流和傅里叶红外响应光谱对单元测试器件进行了评估,针对不同材料结构,实现了9 μm和10.9 μm的截止波长; 黑体探测率最高达到2.6×109 cm·Hz1/ 2·W-1 。 将128×128 AlGaAs/GaAs QWIP阵列芯片与CMOS读出电路芯片倒装焊互连,成功演示了室温环境下目 标的红外热成像;并进一步讨论了提高QWIP组件成像质量的途径。     

Distributed feedback quantum cascade lasers operating in continuous-wave mode at λ≈7.6μm

正Distributed feedback(DFB) quantum cascade lasers(QCLs) in continuous-wave(CW) mode emitting atλ≈7.6μm are presented.Holographic lithography was used to fabricate the first-order distributed feedback grating. For a high-reflectivity-coated QCL with 14.5-μm-wide and 3-mm-long cavity,CW output powers of 300 mW at 85 K and still 10 mW at 270 K are obtained.Single-mode emission with a side-mode suppression ratio(SMSR) of about 30 dB and a wide tuning range of ~300 nm in the temperature range from 85 to 280 K is observed.     

量子照射雷达技术的基本原理与研究进展

通过将传统雷达探测技术与现代量子信息处理技术有机结合,量子雷达在弱反射率目标探测上能够提供经典探测手段无法比拟的优势.作为非常具有潜力的量子雷达类型之一,量子照射雷达以纠缠光子为探测手段,依靠对量子关联特性的测量能够完成目标有无的判断.首先对量子雷达的概念和分类进行了简单介绍;然后对双光子纠缠态量子照射雷达和高斯态量子照射雷达的工作机理与关键技术进行了分析与讨论,并将两种方式的量子照射雷达与经典探测手段进行了性能对比,结果显示量子照射雷达在信噪比、准确性、抗噪性以及隐身性等方面都具有明显的优势;最后指出了量子照射雷达目前存在的问题和未来发展的方向.     

基于雷达测量的多目标联合检测、跟踪与分类方法

利用雷达测量中的目标速度、加速度等属性信息, 基于跳转马尔科夫系统模型高斯混合概率假设密度滤波算法, 提出了一种多目标联合检测、跟踪与分类方法.该方法在进行雷达多目标测量信息处理的多模型混合高斯概率假设密度滤波过程中, 对各高斯项编号, 进行航迹提取, 在滤波处理的同时形成带有航迹编号的明确航迹, 并进行航迹管理; 同时, 根据目标运动模型, 联合利用目标加速度控制输入与速度估计进行多目标分类.仿真试验验证了该方法能够在检测、跟踪的同时, 对目标航迹进行有效类型识别.     

Pressure-Dependent Base-Wavefunction Admixture and Lifetime of R1 State of La3Lu2Ga3O12:Cr3+

As a key factor leading to the pressure-dependent R₁-line-shift reversal and R₁-state lifetime, at 10 K, the pressure-dependent variation of mixing-degree of |t₂²(³T₁)e⁴T₂〉 and |t₂³² E〉base-wavefunctions in the wavefunction of R₁ state of LLGG:Cr³⁺ has been calculated and analyzed. From this, the physical origin of the pressure-dependent R₁-line-shift reversal has been revealed. Furthermore, by using the pressure-dependent values of the sum of all square mixing-coefficients of |t₂²(³T₁)e⁴T₂〉in the wavefunction of R₁ state, the lifetimes of R₁ state of LLGG:Cr³⁺ at various pressures have been calculated, which are in good agreement with observed results. The quantum anticrossing effect between t₂³²E and t₂²(³T₁)e⁴T₂ levels due to both spin-orbital interaction and electron-phonon interaction is remarkable, which is related to the admixture of |t₂²(³T₁)e⁴T₂〉and |t₂³² E〉as well as the low-high crystal-field transition.