Fabrication of transparent ceramics through melt solidification of near eutectic compositions in HfO2–Al2O3–GdAlO3 system

Solidification of eutectic melts in multiple oxide systems can produce directionally solidified eutectic composites by slow cooling, while rapid cooling would give the formation of amorphous phases as super cooled liquids. We have successfully fabricated an amorphous bulk ceramics in the ternary system HfO₂–Al₂O₃–GdAlO₃ for the first time. It has the near eutectic composition of HfO₂ (14 mol%), Al₂O₃ (63 mol%) and Gd₂O₃ (23 mol%) and highly transparent, >85%, in the visible region after the cooling of around 200–500 K/s for 2–5 mm Ø globules. The sample had kept amorphous up to 1073 K but crystallized above 1273 K then lost the transparency. The formation of an amorphous phase could be discussed by the equilibrated temperature (T₀) lines in meta-stable phase diagram. The present study suggests possible formation of transparent bulk ceramics by the melt-solidification of eutectic melts in various ternary or multiple phase systems.     

大功率光伏逆变器输出滤波电抗器有功损耗测量

针对大功率光伏逆变器输出滤波电抗器的有功损耗测量目前受自然环境以及技术条件限制尚未达到工业需求的问题,提出了光伏阵列模拟器和光伏逆变器工作过程的互逆性原理并设计了电力电子变流技术改造光伏逆变器,实现光伏阵列模拟器的功能,并得出相对真实的环境数据搭建有功损耗测试平台.此光伏阵列模拟器测试系统可以准确地测试出各项性能和有功损耗量,相较于目前国内的测试方法,该大功率光伏逆变器输出滤波电抗器有功测量更省时、省力、成本较低且能够达到工业的要求.     

Manganese(III) mediated synthesis of A2B Mn(III) corroles: A new general and green synthetic approach and characterization

A new general and green synthetic protocol for the synthesis of manganese(III) metallocorroles has been developed from substituted aryl aldehydes and 5-(4-nitrophenyl)dipyrromethane using manganese salt as template. This is the first report in the synthesis of corroles: the formation of direct CC bond through metal initiation. This method allows higher working concentrations than those previously reported. The new A₂B manganese(III) metallocorroles were synthesized in good yield for different applications. The single crystal X-ray structure of 10-(3,4,5-fluorophenyl)-5,15-bis(4-nitrophenyl)manganese(III) corrole is also reported and shows that manganese atom is situating atop on macrocyclic plane.     

幼童用智能示警蚕丝被的研发

针对幼童自我控制能力和抵抗力较弱,易因踢被子引发感冒等疾病这一特定场景,通过将微型传感器植入蚕丝被特定部位中,以蓝牙通信方式广播传感器采集到的温度数据,手机APP读取到数据后,利用踢被温度变化逻辑判断模型进行分析,达到设定的逻辑判定条件后,在手机端发出声音和振动示警,开发出能够对踢被进行识别和示警的蚕丝被新产品。最后,根据检测评价指标与方法对试制产品进行了测试。结果显示:在报警时间阈值大于或等于7 min和踢掉全部被子条件下,报警成功率为100%;报警时间阈值偏差延时小于或等于3 min、正常睡眠过程中无误报警;对部分踢被等特殊情况也有一定辨识度。     

合并单元直流偏置对母线保护的影响分析及解决方案

近年来,因合并单元输出直流偏置信号而导致保护动作的事故在智能变电站屡有发生。为解决这一问题,提高合并单元采样值输出的稳定性和安全性,介绍了合并单元工作原理和ADC芯片设计原理,分析了合并单元在采样回路断线时产生直流偏置的原因。基于母线保护装置采样值差动原理,从动作行为方面分析了合并单元直流偏置输出对母线保护的影响。通过改造ADC芯片外围回路,提出了减小合并单元直流偏置的解决方案。搭建了测试系统,通过验证采样值输出值和母线保护动作情况,证明了合并单元直流偏置解决方案的有效性。     

适用于任意几何结构平面阵列的无网格DOA估计算法

由于在网格失配情况下依然具备良好的估计性能,无网格DOA估计算法近年来受到了广泛的关注与研究,其中又以基于原子范数最小化(ANM)的DOA估计算法最具代表性.随着可分离ANM(DANM)算法的提出,为ANM理论在2维DOA估计领域中的应用提供了可能.不过传统的DANM算法以及其后续的一系列改进算法都只适用于均匀矩形阵列...     

The theory of structural superplasticity—I. The physical nature of the superplasticity phenomenon

It is shown that the superplastic deformation in polycrystalline metals results from the grain boundary transition into a special high-excited state characterized by a low resistance to the viscous integrain sliding. The above state occurs in the boundaries due to destabilization of their atomic structure by the fluxes of lattice dislocations effecting the intragranular deformation.     

基于双面组件的可调支架光伏发电系统仿真研究

以双面光伏组件和可调支架系统为基础,以青海格尔木为模拟地点,利用PVsyst光伏仿真软件,分析了不同调节次数的可调支架系统与固定支架系统在组件正面和背面辐射量、系统发电量、系统收益的差异。研究结果表明：通过调节支架改变光伏组件的角度后,组件最低点离地高度也在变化,直接影响组件正面和背面的辐射接收;光伏方阵前后间距影响土地利用率（GCR）,土地利用率降低后,背面的辐射量和系统发电量都有一定的增加;相对于固定支架双面发电系统,可调支架双面系统在不同调节次数下的组件背面全年辐射量均有一定降低,但整体的发电量得益于正面辐射的增益,最高可达4.8%左右;技术和经济比较结果显示,双面组件采用可调支架系统,每年2次的调节方式,25年生命周期内系统收益最高。文章还分析了单面发电组件和双面组件系统使用可调支架的经济性对比,在相同的调节次数下,双面组件系统的增益明显高于单面组件系统。本文的研究成果对可调支架双面组件发电系统的设计具指导作用。     

An algorithm for the computation of the hyper-Wiener index for the characterization and discrimination of branched acyclic molecules

An algorithm for the computation of the hyper-Wiener index ω of trees (i.e. branched acyclic molecules) is presented. The input for the algorithm is the list of connections. Multiple linear regression equation was derived between boiling points, ω and the flexibility index p in series of acyclic heptane, octane and nonane isomers. The multiple correlation coefficients obtained for the regression equations were equal to r = 0.992 (heptane), r = 0.975 (octane) and r = 0.960 (nonane).     

基于动力学特性水声传感网随机游走容错机制

水下传感器节点能量有限、复杂海洋环境影响网络性能下降等因素,制约了水声传感器网络在海洋资源开发、海洋监测等方面的应用推广。为解决水声传感器网络的数据传输负载不均衡、容错能力低等问题,刻画水声传感器网络传播动力学特性,分析复杂海洋环境中传感器节点失效原因,建立了簇结构网络演化模型,提出了一种随机游走容错机制,以提高水声传感器网络容错性和延长其生命周期。仿真实验验证了该模型的合理性和有效性,实验结果表明该机制能揭示水下传感器网络中存在的普遍动力学特性和规律。