改进式相位生成载波调制解调方法

在对调制方法、混频原理、调制深度取值等问题深入研究的基础上,为得到更高的抗干扰能力,结合相位生成载波调制解调技术与微分交叉相乘解调算法,引入除法运算,提出一种改进的相位生成载波解调算法,以抑制光强扰动对解调结果的影响,并与传统的微分交叉相乘解调算法在光源产生低频干扰时的解调效果对比,进行仿真实验.对比信号源分别为20 Hz与200 Hz时的解调效果,结果表明,在光源有1Hz低频扰动的情况下,在高频信号解调的结果中,改进的解调算法可以准确地实现对待测信号的解调,解调结果与传统方法相比具有更高的线性度.     

基于800 mm口径半椭球反射镜的高温材料光谱发射率测量技术

为解决中高温条件下材料发射率的测量问题,提出了一种基于半椭球反射镜的高温材料光谱发射率测量技术。该技术使用800 mm口径半椭球反射镜大范围聚焦信号光,利用3种离轴抛物镜来切换不同测试视场,并利用高功率激光器对样品进行加热。仿真研究了所设计系统的测量误差,结果表明,反射率测量偏差最大为0.035,透射率测量偏差最大为0.031。构建了基于800 mm口径半椭球镜的发射率测量系统,测算了某合金材料和某半透明材料的反射率、透射率和发射率,表明所设计的系统可实现常温到中高温(300～1200 K)、多视场(30°、60°、90°)、宽谱段(2～14μm)的测量。     

基于四极杆-飞行时间质谱的非标记蛋白定量检测方法学研究

以四极杆飞行时间质谱检测的蛋白肽段的质谱信息为基础,开发了一种简单、准确的蛋白定性、定量检测方法,并用于牛血清白蛋白的定性、定量检测。对酶解肽段的梯度洗脱条件和流速等液相色谱条件进行了优化;进行蛋白样品的酶解及质谱检测,利用MassHunter定量软件对数据进行分析;为减少假阳性结果的出现,实验优化了数据处理软件中的设置参数,并对方法的重现性进行了考察。结果显示,重复检测的8个肽段峰面积的RSD均在3.0%以下。该方法对牛血清白蛋白的检出限为100 ng。实验发现,样品中蛋白的含量与检测到的肽段匹配率呈对数关系,并从检测到的丰度较高的8个肽段中确定可用于BSA蛋白定性检测的肽段为:HLVDEPQNLIK,定量检测的肽段为:ATEEQLK,方法的回收率为106%。该方法操作简便,检测快速,成本较低,专一性强,可用于蛋白特异性肽段的筛选及复杂生物样品中蛋白的检测。     

T型微通道装置制备单分散PLGA微球

利用微通道法乳化技术原理,研制了一个可拆卸T型玻璃微通道装置,以聚乙烯醇水溶液为连续相,聚(乳酸-co-羟基乙酸)(PLGA)的二氯甲烷溶液为分散相,制备了单分散的PLGA微球.考察了乳化剂用量、连续相和分散相流速以及PLGA浓度对形成的液滴平均粒径和变异系数(CV值)的影响.结果表明,增大乳化剂用量,提高连续相流速或降低分散相流速,制备得到的PLGA微球直径减小;分散相浓度在5～20 g/L之间变化时,其对微球直径的影响有限.PLGA微球表面光滑无孔,且内部是实心的.用本装置制备得到的PLGA微球,其粒径范围在30～200μm之间,CV值在15%以下,最低可至3%.该方法可使用挥发性有机溶剂作为分散相而且能避免微球制备时易堵塞等问题,可应用于药物缓控释领域中微米级单分散微球的制备.     

Effect of high-temperature annealing on AlN thin film grown by metalorganic chemical vapor deposition

The effect of high-temperature annealing on AlN thin film grown by metalorganic chemical vapor deposition was investigated using atomic force microscopy, Raman spectroscopy, and deep ultra-violet photoluminescence(PL) with the excitation wavelength as short as ～ 177 nm. Annealing experiments were carried out in either N2 or vacuum atmosphere with the annealing temperature ranging from 1200℃ to 1600℃. It is found that surface roughness reduced and compressive strain increased with the annealing temperature increasing in both annealing atmospheres. As to optical properties,a band-edge emission peak at 6.036 eV and a very broad emission band peaking at about 4.7 eV were observed in the photoluminescence spectrum of the as-grown sample. After annealing, the intensity of the band-edge emission peak varied with the annealing temperature and atmosphere. It is also found that a much stronger emission band ranging from 2.5 eV to 4.2 eV is superimposed on the original spectra by annealing in either N2 or vacuum atmosphere. We attribute these deep-level emission peaks to the VAL–ONcomplex in the AlN material.     

Propagation modeling of ocean-scattered low-elevation GPS signals for maritime tropospheric duct inversion

The maritime tropospheric duct is a low-altitude anomalous refractivity structure over the ocean surface,and it can significantly affect the performance of many shore-based/shipboard radar and communication systems.We propose the idea that maritime tropospheric ducts can be retrieved from ocean forward-scattered low-elevation global positioning system(GPS) signals.Retrieval is accomplished by matching the measured power patterns of the signals to those predicted by the forward propagation model as a function of the modified refractivity profile.On the basis of a parabolic equation method and bistatic radar equation,we develop such a forward model for computing the trapped propagation characteristics of an ocean forward-scattered GPS signal within a tropospheric duct.A new GPS scattering initial field is defined for this model to start the propagation modeling.A preliminary test on the performance of this model is conducted using measured data obtained from a 2009-experiment in the South China Sea.Results demonstrate that this model can predict GPS propagation characteristics within maritime tropospheric ducts and serve as a forward model for duct inversion.     

Short-wavelength InAlGaAs/AlGaAs quantum dot superluminescent diodes

This paper reports the fabrication of J-shaped bent-waveguide superluminescent diodes utilizing an InAlGaAs/AlGaAs quantum dot active region. The emission spectrum of the device is centred at 884 nm with a full width at half maximum of 37 nm and an output power of 18 mW. By incorporating an Al composition into the quantum dot active region, short-wavelength superluminescent diode devices can be obtained. An intersection was found for the light power-injection current curves measured from the straight-waveguide facet and the bent-waveguide facet, respectively. The result is attributed to the conjunct effects of the gain and the additional loss of the bent waveguide. A numerical simulation is performed to verify the qualitative explanation. It is shown that bent waveguide loss is an important factor that affects the output power of J-shaped superluminescent diode devices.     

有界控制导弹攻击防御性飞机的制导律

为提高攻击导弹同时面对目标飞机及其防御导弹情况下的命中概率,基于微分对策理论,对攻击导弹的制导律进行了设计。应对独立控制的多对象博弈问题,微分对策理论具有天然的优势,且相比于最优制导律,微分对策制导律对于目标机动估计误差和机动策略具有更强的鲁棒性。所推导的微分对策制导律进一步考虑了攻击导弹的控制有界性,且适用于攻击导弹、目标飞机和防御导弹具有高阶线性控制系统动态的情形。为验证制导律性能,进行了非线性系统仿真,结果表明该制导律在成功归避防御导弹的同时可实现趋于零脱靶量的目标拦截。攻击导弹为实现规避和攻击的双重任务,仅需要保持相比于防御导弹两倍左右的机动优势。     

交易流动性不对等环境下基于收入共享契约的供应链协调

供应链中存在单一生产商、单一零售商和一个交易流动性不对等的第三方B2B电子交易市场。在零售需求不确定的情况下,分别建立了供应链集中决策模型、传统固定合约均衡决策模型、收入共享契约分散决策模型,验证了收入共享契约在多渠道采购环境下仍可以协调供应链,分析了使供应链达到帕累托改进的收入共享契约的参数设定,最后分别从卖出流动性和买入流动性两个角度讨论了交易流动性对供应链的影响。研究结果表明,卖出流动性好的电子交易市场可以促使供应链达到最优生产量,实现整体收益的最大化;两种交易流动性的趋好都会提高供应链效率,但生产商更偏好卖出流动性好的电子交易市场。