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。     

高效液相色谱法分析高吸水性树脂中的丙烯酸单体

建立了一种快速测定高吸水性树脂中丙烯酸单体残留的高效液相色谱法,采用常见的Agilent XDB-C18柱(250mm×4.6mm,5μm),流动相为甲醇-0.1%H_3PO_4水溶液,检测波长为210nm,外标法定量。试样的加标浓度为0.50、5.0、20.0μg/mL时,加标回收率在76.0%—97.5%之间,RSD≤3.27%;方法的检出限为60.0ng/mL,线性范围是0.50—25.0μg/mL,相关系数可达0.9995,此方法成功应用于个人护理领域高吸收性树脂中丙烯酸单体残留的分析。     

Effect of Kinetic Alfvén Waves on Electron Transport in an Ion-Scale Flux Rope

At the Earth's magnetopause, the electron transport due to kinetic Alfvén waves(KAWs) is investigated in an ion-scale flux rope by the Magnetospheric Multiscale mission. Clear electron dropout around 90° pitch angle is observed throughout the flux rope, where intense KAWs are identified. The KAWs can effectively trap electrons by the wave parallel electric field and the magnetic mirror force, allowing electrons to undergo Landau resonance and be transported into more field-aligned directions. The pitch angle range for the trapped electrons is estimated from the wave analysis, which is in good agreement with direct pitch angle measurements of the electron distributions. The newly formed beam-like electron distribution is unstable and excites whistler waves,as revealed in the observations. We suggest that KAWs could be responsible for the plasma depletion inside a flux rope by this transport process, and thus be responsible for the formation of a typical flux rope.     

基于不同散射机制特征的海杂波时变多普勒谱模型

海杂波的多普勒谱建模对采用多普勒处理技术的雷达进行有效的海杂波抑制和目标检测具有重要的意义.本文分别考虑Bragg,白冠和破碎波三种散射机制对应的多普勒谱分量的特征,对三种谱分量的频移和展宽进行分离,并引入附加速度频移量,提出了基于不同散射机制特征的雷达海杂波时变多普勒谱模型.该模型假设谱强度为受观测时间区间影响的随机变量,能够同时适用于平均多普勒谱与短时多普勒谱建模.通过分别对黄海海域实测的岸基P,S波段海杂波平均多普勒谱与短时多普勒谱建模测试,结果表明该模型相对传统模型的建模精度更高,尤其体现在短时谱的观测时间较长和平均谱形式较为复杂的情况下,建模误差显著减小.     

Fast pore etching on high resistivity n-type silicon via photoelectrochemistry

In this paper, five factors, namely the HF (hydrofluoric acid) concentration, field strength, illumination intensity as well as the oxidizing-power and conductivity of electrolytes were found to strongly affect the fast pore etching. The oxidizing power of aqueous HF electrolyte of different concentrations was especially measured and analysed. A positive correlation between optimal bias and HF concentration was generally observed and the relationship was semi-quantitatively interpreted. Pore density notably increased with enhanced HF-concentration or bias even on patterned substrates where 2D (two-dimensional) nuclei were densely pre-textured. The etch rate can reach 400μm/h and the aspect ratio of pores can be readily driven up to 250.     

Enhancing redshift phenomenon in time-resolved photoluminescence spectra of AlGaN epilayer

AlGaN epitaxial layer has been studied by means of temperature-dependent time-integrated photoluminescence(PL)and time-resolved photoluminescence(TRPL). An enhancing redshift phenomenon in TRPL spectra with increasing temperature was observed, and the localized excitons behaved like quasi two-dimensional excitons between 6 K and 90 K. We demonstrated that these behaviors are caused by a change in the carrier dynamics with increasing temperature due to the competition of carriers' localization and delocalization in the AlGaN alloy.     

3-三苯基锗基-1,1-二苯基-1-丁醇类化合物的拉曼光谱和红外光谱研究

我们合成３－三苯基锗基－１,１－二苯基－１－丙醇及同系物３－三苯基锗基－１,１－二苯基－１－丁醇;３－三苯基锗基－２－甲基－１,１－二苯基－１－丙醇,这些化合物都是有机锗类化合物,是具有抗肿瘤活性的化合物３－三苯基锗基－１－二苯基－１－丙醇的类似物,它们可能具有生物活性。我们测量了它们的拉曼光谱及红外光谱。经光谱分析,指认了主要波数所对应的分子振动。在这三种化合物中,Ｇｅ－Ｐｈ的伸缩振动出现在１０     

沙枣花油成份的研究

沙枣(Elaeagnus.angustifalia.L,胡颓子科胡颓子属)。是我国西北地区特有的野生耐旱植物。生长面积很大,是防风固沙的优良树种。每年4—5月开花,6—7月结果,果实即为沙枣。沙枣花能散发出持久的清香,这种独特的香味深为人们所喜爱。我们为了开辟一种新的天然香源,对沙枣花香气成份进行了研究。先后采用了吸附、