三量子比特系统中单个谐振子诱导的量子关联

我们考虑初始无关联并且与由一个谐振子构成的环境之间互相耦合的三量子比特系统。通过研究量子比特-环境的耦合强度以及量子比特初始态对量子关联的影响,我们发现环境可以诱导量子关联,提出并证明了四个命题阐述谐振子如何调控三个量子比特中量子关联的分布。给出了产生量子关联的条件。特别地,对于弱耦合,我们不但能够获得很多的量子关联,而且还使量子比特系统和环境始终处于分离态。一般地,量子关联动力学是很复杂 的,这是由于环境起着两个互相竞争的作用：一方面诱导出各个比特之间的量子关联;另一方面又使它们发生消相干,从而破坏量子关联。     

三量子比特系统中单个谐振子诱导的量子关联

我们考虑初始无关联并且与由一个谐振子构成的环境之间互相耦合的三量子比特系统。通过研究量子比特-环境的耦合强度以及量子比特初始态对量子关联的影响,我们发现环境可以诱导量子关联,提出并证明了四个命题阐述谐振子如何调控三个量子比特中量子关联的分布。给出了产生量子关联的条件。特别地,对于弱耦合,我们不但能够获得很多的量子关联,而且还使量子比特系统和环境始终处于分离态。一般地,量子关联动力学是很复杂 的,这是由于环境起着两个互相竞争的作用：一方面诱导出各个比特之间的量子关联;另一方面又使它们发生消相干,从而破坏量子关联。     

浅海波导中简正波干涉特征频率增强

针对浅海波导中水平线列阵接收的低频宽带低信噪比信号,提出了一种利用多拍信号相干累加来提高干涉简正波特征频谱信噪比的方法。这种方法主要针对未知距离和声源形式的运动声源,对不同时刻（或接收距离）处阵列输出信号进行WARPING变换,基于干涉简正波特征频率不变性原理,通过距离和径向速度比值的搜索来使得不同时刻或距离处信号自相关函数WARPING变换后频谱具有近似相同的特征频率,进而通过相干累加来增强信号干涉简正波特征频率。仿真和海上实验数据分析均验证了方法的性能。     

超声雾化反应法制备CeO2纳米粉体

以硝酸铈和碳酸氢铵为原料,采用超声雾化反应法制备了纳米CeO2粉. 用红外光谱(IR)、 X射线衍射分析(XRD)和透射电子显微镜(TEM)技术,对制得的纳米CeO2纳米粒子的物相结构、形貌特征、成分等进行了表征. 结果表明,双液超声雾化法能制备出颗粒分散性好,粒度分布均匀的纳米CeO2粒子,所得CeO2粒子为萤石型结构,粒径约为3～5 nm左右. 初步探讨了用超声雾化反应法制备纳米粉的机制,认为CeO2纳米粒子的成核和长大受到液滴大小的限制,是一个液相的微区反应过程,正是液滴的微小体积保证了更小纳米粒子的形成.     

Facile Preparation and Lithium Storage Properties of TiO2@Graphene Composite Electrodes with Low Carbon Content

Over the past decade, TiO₂/graphene composites as electrodes for lithium ion batteries have attracted a great deal of attention for reasons of safety and environmental friendliness. However, most of the TiO₂/graphene electrodes have large graphene content (9–40 %), which is bound to increase the cost of the battery. Logically, reducing the amount of graphene is a necessary part to achieve a green battery. The synthesis of TiO₂ nanosheets under solvothermal conditions without additives is now demonstrated. Through mechanical mixing TiO₂ nanosheets with different amount of reduced graphene (rGO), a series of TiO₂@graphene composites was prepared with low graphene content (rGO content 1, 2, 3, and 5 wt %). When these composites were evaluated as anodes for lithium ion batteries, it was found that TiO₂+3 wt % rGO manifested excellent cycling stability and a high specific capacity (243.7 mAh g^?1 at 1 C; 1 C=167.5 mA g^?1), and demonstrated superior high‐rate discharge/charge capability at 20 C.     

微波法制备石墨烯及石墨烯基材料的研究进展

石墨烯(Gr)由于其独特的单原子层二维结构及优异的性能,在材料、电子、化学、能源、生物医药等众多领域具有广阔的应用前景,引起了众多学者的研究兴趣。如何高产量获得高质量的Gr对其未来的开发和应用至关重要。微波法是制备Gr的重要方法之一,具有绿色、高效、简便快捷等特点。本文综述了近几年微波法制备Gr、掺杂Gr和Gr基纳米复合材料的研究进展以及后者在锂离子电池负极材料方面的应用,并对其发展方向进行了展望。     

Z-pinch X射线时间分辨多幅图像诊断系统

 介绍了为“强光一号”设计的ns级时间分辨软X射线多幅图像诊断系统，分析了系统的主要性能指标,给出并分析了利用该系统诊断“强光一号”高功率脉冲Z pinch等离子体辐射源的最新的实验结果。     

超声速长波红外整流罩材料研究进展

采用长波红外制导的超声速导弹具有极佳的军事应用前景,但高速飞行的导弹整流罩会承受较高的气动冲击以及砂蚀、雨蚀,极易出现结构和光学性能失效,因此选择与服役环境相匹配的整流罩材料至关重要.基于上述应用现状,本文综述了目前主要研究的几种长波红外整流罩材料,对其光热理化性能及应用前景进行了分析,同时对几款整流罩材料或结构的发展方向进行了展望,旨在为超声速长波红外整流罩的选材提供技术参考.     

Biocatalytic Performance of pH‐Sensitive Magnetic Nanoparticles Derived from Layer‐by‐Layer Ionic Self‐Assembly of Chitosan with Glucoamylase

Based on the characteristics of polycations of chitosan and glucoamylase, which are oppositely charged, they were successfully alternatingly deposited onto the surface of aldehyde‐modified Fe₃O₄ nanoparticles by using a layer‐by‐layer ion exchange method to form magnetic carriers to construct multilayer films (designated as Fe₃O₄@(CS/GA)_n). The (CS/GA)_n film systems were endowed with the pH‐dependent properties of chitosan as well as the catalytic activity of glucoamylase. The changes in weight loss and surface chemistry, morphology, and magnetic sensitivity were monitored and verified by UV/Vis spectroscopy, zeta potential, TEM, and a vibrating sample magnetometer. Subsequently, the influence of the number of bilayers, storage stability, pH, temperature, and reusability of Fe₃O₄@(CS/GA)₅ biocatalysts on catalytic activity were investigated. The results from characterization and determination remarkably indicate that Fe₃O₄@(CS/GA)₅ presents excellent catalytic activity, storage stability, pH stability, and reusability in comparison with free enzyme. Fe₃O₄@(CS/GA)₅ retained >60 % of its initial activity at 65 °C over 6 h; the optimum temperature and pH also increased to the ranges of 45–65 °C and 2.5–3.5, respectively, and only 27 % activity was lost after 10 cycles. This new strategy simplifies the reaction protocol and improves encapsulation efficiency and catalytic activity for new potential applications in biotechnology.     

原子吸收光谱法测定电解金属锰中微量金属杂质元素

本文用盐酸溶解样品,火焰原子吸收光谱法测定电解金属锰中K,Na,Ca,Mg,Fe,石墨炉原子吸收光谱法测定其中的Cr,Cu,Co,Ni含量。对测定条件进行了实验,找出最佳溶样方法和酸度,对共存元素的干扰有排除亦进行了试验,获得了满意的效果。该法简便、快速、准确,加标回收率为88.9%-108.7%之间,相对标准偏差为0.6%-6.7%,标准曲线法、标准加入法结果与对照结果相吻合,适用于电解金属锰样品金属杂质元素的分析。