Output regulation for a class of uncertain nonlinear systems with nonlinear exosystems and its application

In this paper, we consider the global robust output regulation problem for a class of uncertain nonlinear systems with nonlinear exosystems. By employing the internal model approach, we show that this problem boils down to a global robust stabilization problem of a time-varying nonlinear system in lower triangular form, the solution of which will lead to the solution of the global robust output regulation problem. An example shows the effectiveness of the proposed approach.     

基于用例的装备保障数据仓库功能设计

为了解决装备保障数据仓库构建中功能设计这一难点问题,采用用例的方式对其功能体系进行描述。通过UML用例图,建立起决策支持功能、业务功能、运维功能的装备保障数据仓库功能体系,并对相关要素进行说明。用例图直观地展现了数据仓库功能,极大地方便了用户与开发人员之间的沟通,提高了装备保障数据仓库开发过程中功能模块的设计效率。     

The comparison: photoluminescence and afterglow behavior in CaSnO<Subscript>3</Subscript>:Dy<Superscript>3+</Superscript> and Ca<Subscript>2</Subscript>SnO<Subscript>4</Subscript>:Dy<Superscript>3+</Superscript> phosphors

This paper reports the comparison of photoluminescence and afterglow behavior of Dy³⁺ in CaSnO₃ and Ca₂SnO₄ phosphors. The samples containing CaSnO₃ and Ca₂SnO₄ were prepared via solid-state reaction. The properties have been characterized and analyzed by utilizing X-ray diffraction (XRD), photoluminescence spectroscope (PLS), X-ray photoelectron spectroscopy (XPS), afterglow spectroscopy (AS) and thermal luminescence spectroscope (TLS). The emission spectra revealed that CaSnO₃:Dy³⁺ and Ca₂SnO₄:Dy³⁺ phosphors showed different photoluminescence. The Ca₂SnO₄:Dy³⁺ phosphor showed a typical ⁴F_9/2 to ⁶H_j energy transition of Dy³⁺ ions, with three significant emissions centering around 482, 572 and 670 nm. However, the CaSnO₃:Dy³⁺ phosphor revealed a broad T₁ → S₀ transitions of Sn²⁺ ions. The XPS demonstrate the existence of Sn²⁺ ions in CaSnO₃ phosphor caused by the doping of Dy³⁺ ions. Both the CaSnO₃:Dy³⁺ and Ca₂SnO₄:Dy³⁺ phosphors showed a typical triple-exponential afterglow when the UV source switched off. Thermal simulated luminescence study indicated that the persistent afterglow of CaSnO₃:Dy³⁺ and Ca₂SnO₄:Dy³⁺ phosphors was generated by the suitable electron or hole traps which were resulted from the doping the calcium stannate host with rare-earth ions (Dy³⁺).     

Evaluation of numerical ablation model for charring composites

Charring composites are widely used in the thermal protection system(TPS) to consume the intense aerodynamic heating during vehicle reentry. The ablation and thermal responses for the charring composites can be studied by using a numerical ablation model, in which the surface ablation and volume ablation could be taken into account. The coupling interactions among temperature, gas motion and interior pressure producing the pyrolysis gas could make the computation more complicated. A multi-physics model is developed to simulate the thermal response coupled with volume ablation and surface ablation. After studying four typical ablation cases, the model is validated, and then the heat transfer mechanisms in ablation are investigated. It is found that the viscous dissipation energy by the motion of pyrolysis gas can be neglected in the simulation. Also, the flow of pyrolysis gas plays an important role in the temperature response, especially under high heat flux condition.     

共振多光子电离探测芳香烃污染物对比实验研究

本文用两种不同的方法对同期制备的不同浓度的苯、甲苯、二甲苯及其混合气和摩托车尾气三类样品分别进行了对比实验,实验验证了多光子电离所得实验数据的可靠性及其测量精确性,同时可以看出多光子电离方法所具有的快速、实时在线和多组分同时探测的优越性。     

Propagation properties of foreshock cavitons: Cluster observations

Foreshock cavitons are transient phenomena observed in the terrestrial foreshock region. They are characterized by a simultaneous depression of magnetic field magnitude and plasma density, which are bounded with enhancements of these two parameters and surrounded by ultralow frequency(ULF) waves. Previous studies focused on the interplanetary magnetic field(IMF) conditions, solar wind(SW) conditions, and the growth of the foreshock waves related to the generation of foreshock cavitons. Previously, a multipoint spacecraft analysis method using Cluster data was applied to analyze only two foreshock cavitons, and this method did not consider uncertainties. In this study, multipoint spacecraft analysis methods, including the timing method, the minimum directional derivative(MDD) method, and the spatiotemporal difference(STD) method are applied to determine the velocity in both spacecraft and solar wind frames. The propagation properties show good agreement with previous results from simulations and observations that most cavitons move sunward in the solar wind frame, with the velocities larger than the Alfvén speed. The propagation properties of foreshock cavitons support the formation mechanism of cavitons in previous simulations, which suggested that cavitons are formed due to the nonlinear evolution of compressive ULF waves. We find that there is clear decreasing trend between the size of cavitons and their velocity in the solar wind frame. In addition, the timing method considering errors has been applied to study the evolution properties by comparing the velocities with errors of the leading and trailing edges, and we identify three stable cavitons and one contracting caviton, which has not been studied before.Most cavitons should remain stable when they travel toward the Earth's bow shock. The relationship between the size of foreshock cavitons and their distance from the bow shock is also discussed.     

Effects of nanoparticles on devitrification and recrystallization of aqueous glycerol and PEG-600 solutions

Nanoparticles in solution offer unique electrical,mechanical and thermal properties due to their physical presence and interaction with the state of dispersion.This work is aimed to study the effects of hydroxyapatite(HA)nanoparticles on the behavior of devitrification and recrystallization of glycerol(60%w/w)and PEG-600(50%w/w)solutions during warming.HA nanoparticles of different sizes(20,40,60 nm)and concentrations(0.1%,0.5%,w/w)were incorporated into solutions,and were studied by calorimetric analysis coupled with cryomicroscopy.The presence of HA nanoparticles has little effect on the devitrification end temperatures,but affects the devitrification onset temperatures of glycerol and PEG-600 solutions.The investigation with the cryomicroscope observed that the ice morphologies of glycerol and PEG-600 solutions are dendritic and spheric respectively.The ice fraction of glycerol solution containing 0.1%HA with the size of 60 nm decreased to 2/5 of that of the solution without nanoparticles at 45°C.The ice fractions of PEG-600 solutions increased significantly between 64°C and54°C,and the ice fraction of PEG-600 solution without nanoparticles increased by 92%within the temperature range.The findings have significant implications for biomaterial cryopreservation,cryosurgery,and food manufacturing.The complexity of ice crystal growth kinetics in nanoparticle-containing solutions awaits further study.     

上海，索尼的第五个创意中心

索尼中国设计工程集团“CREATIVE CENTER”在上海正式成立．CREATIVE CENTER将主要为索尼在中国设计的产品进行外观．界面及创意等工业设计。这是继东京．洛杉矶，伦敦．新加坡之后索尼在全球开设的第五个CRE-ATIVE CENTER创意中心。就此我们特别采访了索尼公司执行副总裁兼首席运营官驻中国总代表高莜静雄先生及索尼（中国）有限公司中国设计工程集团创意中心副总裁山砥克己先生。     

稀土含量对高密度钨合金性能的影响

通过粉末冶金法制备了添加稀土元素La，Ce的93W-4．9Ni-2．1Fe合金，研究不同稀土元素及不同稀土含量对高密度93钨合金静、动态力学性能的影响规律。结果表明：由于稀土元素La，Ce的加入，减少了杂质元素氧在钨-粘结相界面的偏析，减小了钨颗粒的连接度，从而改善了钨合金的力学性能，尤其是合金的动态力学性能得到显著提高，稀土元素的合理添加量为0．10％～0．15％。     

基于双DSP的信号处理板的设计及其在SAR信号仿真中的应用

针对SAR信号仿真系统高速实时数据处理和传输的要求,本文设计并实现了基于双DSP结构的高性能实时信号处理板。该板使用两片TMS320C6416作为信号处理核心和数据流控制中心,使用PCI-PCI桥接芯片PCI2050B对PCI总线进行了扩展,并使用两片FPGA实现了内部高速互联通道和外部LVDS高速接口,具有很强的可重构性和可扩展性,并可在多种模式下工作。实测结果表明,该设计可完全满足SAR信号仿真的性能需求。