Energy band structure of spin-1 condensates in optical lattices

The energy band structure of spin-1 condensates with repulsive spin-independent and either ferromagnetic or antiferromagnetic spin-dependent interactions in one-dimensional (1D) periodic optical lattices is discussed. Within the two-mode approximation, Bloch bands of spin-1 condensates are presented. The results show that the Bloch bands exhibit a complex structure as the atom density of m F=0 hyperfine state increases: bands splitting, reversion, intersection and loop structure are excited subsequently. The complex band structure should be related to the tunneling and spin-mixing dynamics.     

Hawking radiation of Kerr–Newman–de Sitter black hole

We extend the classical Damour–Ruffini method and discuss Hawking radiation in Kerr–Newman–de Sitter (KNdS) black hole. Under the condition that the total energy, angular momentum and charge of spacetime are conserved, taking the reaction of the radiation of the particle to the spacetime and the relation between the black hole event horizon and the cosmological horizon into consideration, we derive the black hole radiation spectrum. The radiation spectrum is no longer a pure thermal one. It is related to the change of the Bekenstein–Hawking entropy corresponding the black hole event horizon and the cosmological horizon. It is consistent with the underlying unitary theory.     

Microstructure and dielectric properties of PMN–PT ceramics prepared by the molten salts method

The sintering characteristic and dielectric properties of 0.67PMN–0.33PT ceramics prepared by the molten salt synthesis (MSS) method were investigated. PMN–PT particles synthesized by MSS with smaller grain size and good dispersion could lower the sintering temperature of ceramics; PMN–PT ceramics with relative density above 96% could be obtained in the range 1150–1180 °C. The molten salts species could significantly affect the microstructure and properties of MPN-PT ceramics. In the range 1100–1200 °C, PMN–PT ceramics from the sulfate flux MSS powders showed intergranular fracture, but that from the chloride flux MSS powder showed transgranular fracture. At the same sintering condition, the properties of PMN–PT ceramics from the powders prepared in the chloride flux are better than that from the powders prepared in the sulfate flux, their maximum dielectric constant ε_max≈29,385 and piezoelectric constant d₃₃≈660 pC/N. The above results demonstrated that PMN–PT ceramics prepared by the molten salts method possessed excellent piezoelectric and dielectric properties.     

Optical modulator based on negative refractive material

Using negative refractive material slow-wave waveguide, a compact and integrated optical modulator is proposed for the first time to our knowledge. The slow group velocities of light, which are readily achievable in negative refractive material waveguide, can dramatically increase the induced phase shifts caused by small changes in the refractive index. Modulation operation with a 40 μm long negative refractive material slow-wave waveguide of a Mach–Zehnder interferometer (MZI) structure was demonstrated by using finite-element method. The size of the novel optical modulator is 100 times shorter than that of the conventional lithium niobate MZI optical modulator.     

基于经验模态分解和小波阈值的冲击信号去噪

冲击信号是非线性的并且容易受到噪声污染。为研究冲击信号去噪的问题,本文针对经验模态分解(Empirical Mode Decomposition,EMD)去噪和小波阈值去噪方法存在的不足,提出了基于EMD的小波阈值去噪方法。单纯的EMD去噪方法会在去除高频噪声的同时压制高频的有效信息。本文将EMD与小波阈值去噪相结合,利用连续均方误差准则确定含噪较多的高频固有模态函数(Intrinsic Mode Function, IMF),对高频IMF分量进行小波阈值去噪,以分离并保留这些分量中的有效信息,同时保持低频IMF分量不变。对模拟数据和实际冲击信号进行去噪处理,结果表明,基于EMD的小波阈值去噪方法的去噪效果优于单纯的EMD去噪方法和小波阈值去噪方法。     

电子式互感器高频数据采集与传输方案

针对当前电力系统电子式互感器采样率偏低,难以满足行波测距装置准确定位电力故障的问题,提出了电子式互感器高频信号采集与传输方案;电子式互感器内部为Rogowski 线圈,电网电流信号被其微分作用转换为小电压信号并附加了90°超前相差,设计积分电路补偿该相差;设计采样率为2 MSps的高频信号采集电路,FPGA通过LVDS接口读取采样数据,并进行幅值处理,最后利用大容量FIFO(先入先出单元)进行缓存;由于百兆网数据传输速率有限,利用FPGA设计吉比特光纤以太网传输特定格式报文,把电流数据传输至电力行波测距装置;解决了积分电路由于运放输入偏置电压带来的积分饱和问题,以及高速ADC输入量程小于输入信号幅值等技术难点;试验结果表明,高频信号采集及传输方案能够满足行波测距装置百米级别的测距精度要求,具有一定工程应用价值。     

基于飞行载荷的大数据实测方法研究

飞行载荷实测是全面、定量评定飞机结构强度的必要环节,在飞行试验中起着至关重要的作用。传统的有人机、小型机载荷标定需要评测的参数仅需要数十个或几十个关键参数,实时采集系统通道量较小,实时监控系统服务器压力较小。随着航空工业的飞速发展,大型机、无人机等需要评定的参数量急速上升到数百个,而采集通道成为瓶颈,传统的测量方法难以满足需求。针对飞行载荷实测的海量参数难以测试问题,文章提出了一种通道复用的方案,良好的解决了海量数据难以实时测量问题。经验证,该方案可良好的运用在各种型号的飞行载荷海量数据实测中。     

面向智慧城市的物联网基础设施关键技术研究

智慧城市是利用物联网等新一代信息技术实现城市智慧运行和管理的新型城市形态,是信息技术与城市发展深度融合的产物。针对当前智慧城市因碎片化、烟囱式发展模式而面临的重复建设严重、跨域资源难以共享与联动协同等突出问题,从资源汇聚和促进城市应用互联互通互操作的角度,定义了城市物联网基础设施的概念内涵,提出城市物联网基础设施是一个涵盖“网络 平台 服务”的综合体,分析总结了国内外政府与企业在城市物联网基础设施尤其是物联网平台方面的发展现状,在此基础上,研究提出了为实现城市物联资源泛在接入、网络融合、资源管理和智能服务等核心功能亟需突破的关键技术,最后给出了推动城市物联网基础设施快速发展的意见和建议。     

基于互联网+的高校能源管理信息系统设计与开发

为了实现高校能源管理的信息共享,提高对高校能源信息管理的智能水平,提出一种基于互联网+的高校能源管理信息系统开发设计方案。系统采用感知层、网络层和应用层的三层结构,采用RFID、 条形码、蓝牙、红外等数据信息感知技术进行高校能源信息的原始采集,在网络层通过ZigBee 和无线通信技术进行信息融合传输,在控制设备中导入原始数据,在互联网+环境下建立数据处理中心,根据能源管理系统的现实需求进行信息融合和数据存储管理,设计嵌入式控制器对串口、并口、USB端口、以太网口及GPIB接口进行集成控制,在Linux内核下实现高校能源管理信息系统应用程序开发。系统测试结果表明,采用该系统进行高校能源管理,具有较好的信息存储、信息调度和信息检索能力。     

软体微手鲁棒非线性控制设计

软体驱动器是构建智能软体机器人的基石。然而,由于软体驱动器具有非线性、耦合和不确定性等复杂的特性,如何对其进行有效建模与控制是目前极需解决的难题。以一种由三支单腔双向弯曲软驱动器构成的软体微手为研究对象,对其进行了鲁棒非线性控制设计研究。首先,进行了鲁棒非线性控制系统的总体结构设计分析。其次,对如何设计算子控制器、跟踪控制器、算子观测器实现其对软体微手的弯曲角度和力进行控制进行了分析和讨论。接着,分析和研究了鲁棒稳定和跟踪条件。最后,通过基于实验数据的仿真验证了所提方案的可行性和有效性。