Dynamics and genetic fuzzy neural network vibration control design of a smart flexible four-bar linkage mechanism

In this paper, a dynamic modeling method and an active vibration control scheme for a smart flexible four-bar linkage mechanism featuring piezoelectric actuators and strain gauge sensors are presented. The dynamics of this smart mechanism is described by the Discrete Time Transfer Matrix Method of Multibody System (MS-DTTMM). Then a nonlinear fuzzy neural network control is employed to suppress the vibration of this smart mechanism. For improving the dynamic performance of the fuzzy neural network, a genetic algorithm based on the MS-DTTMM is designed offline to tune the initial parameters of the fuzzy neural network. The MS-DTTMM avoids the global dynamics equations of the system, which results in the matrices involved are always very small, so the computational efficiency of the dynamic analysis and control system optimization can be greatly improved. Formulations of the method as well as a numerical simulation are given to demonstrate the proposed dynamic method and control scheme.     

Magnetic properties and microstructural characteristics of bulk Nd–Al–Fe–Co glassy alloys

Bulk Nd–Al–Fe–Co glassy alloys with diameter up to 5 mm were investigated by magnetic measurements, magnetic force microscopy (MFM) and high resolution electron microscopy (HREM) at room temperature. The results from the measurement of vibrating sample magnetometer show that these samples with compositions Nd₆₅Al₁₀Fe_25-xCo_x (x=0–10 at.%) and Nd₆₀Al₁₀Fe₂₀Co₁₀ display hard magnetic properties with H_C of 300 kAm⁻¹, M_S of 10 Am² kg⁻¹, and M_r of 7 Am² kg⁻¹. The MFM measurements of the Nd₆₀Al₁₀Fe₂₀Co₁₀ bulk metallic glass (BMG) reveal the existence of magnetic domains with a period of about 0.36 μm, and the ordered clusters with the averaged size of about 5 nm was observed by the HREM on the sample. The domain structure or cluster is believed to be associated with the appearance of hard-magnetic properties in this alloy system. The existence of the large-size domains demonstrates that magnetic moment of a great deal of ordered atomic clusters in the BMG has been aligned by exchange-coupling.     

基于Q学习的电网运行断面动态生成方法

电网运行断面是电力系统运行控制的重要手段.面对当前繁多的电网运行断面智能生成方法,如何合理的选择已成为电网运行断面在线生成算法领域研究的重要内容.在此背景下,提出一种基于Q学习的电网运行断面动态生成方法.该方法的主要特征在于训练得到Q学习智能体,根据电网运行特征动态选择电网运行断面生成方法,以便充分利用不同生成方法在不同场景下的算法优势.最后,基于某电网数据构造的算例表明,动态生成方法能够通过优化选择不同场景下的生成算法,提升生成结果的准确率.对于应用样本集,该方法提高准确率近5.2％.     

塑料注射模冷却系统的设计

分析和列举了注射模冷却系统设计的要点及注意事项；介绍了用CAE技术优化冷却系统设计的方法。     

笔式界面软件资源管理模型及其实现*

针对目前文档管理模式和WIMP界面交互范式对笔式交互的不足,提出了笔式界面软件文档资源管理的统一模型,能够有效地管理笔式界面软件所产生的文档数据,并且根据此模型实现了笔式界面的文档资源管理系统,采用了PIBG交互范式和实物界面.评估结果表明,根据此模型设计的系统,能够提高用户工作效率,降低用户的认知负担.     

One-step fabrication superhydrophobic sand filter for capillary-driven separation of water-in-oil emulsions

The efficient separation of water-in-oil emulsion is of significance in environment and energy filed, and it has become a world-wide challenge. Herein, we have presented a one-step, facile and low-cost approach to prepare superhydrophobic sands for efficient separation of water-in-oil emulsion. The as-prepared sand layers possessed a water contact angle higher than 151°, demonstrating their superior superhydrophobic property. Besides, the as-prepared sand layers could separate water-in-emulsions with separation efficiency up to 99.7%, which is superior to both traditional and superwettable filtration membranes. The effect of thickness of sand layer on separation performance was also investigated. The results showed that the filtration flux decreased with the increased of filtration thickness while the separation efficiency increased. The as-prepared sand layer proposed by this study is a processing candidate for separating water-in-oil emulsion in practical industry. Additionally,the as-prepared superhydrophobic sand fabrication method also provides an alternative for desert water storage.     

系统振荡对变压器阻抗保护的影响测试方法研究

对于变压器阻抗保护,系统振荡时测量阻抗的幅值与相角都会发生周期性的变化,为避免测量阻抗进入保护的动作区时保护误动作,变压器阻抗保护增加振荡闭锁逻辑.简要介绍了系统振荡对变压器阻抗保护影响的三种测试方法,并对比三种方法的利弊.     

Facile Modification of Biochar Derived from Agricultural Straw Waste with Effective Adsorption and Removal of Phosphorus from Domestic Sewage

Journal of Inorganic and Organometallic Polymers and Materials - In recent decades, straw waste is the major byproduct around agriculture that has become one of the factors of environmental...     

新能源汽车电池负极材料的制备与性能研究

采用原位合成法制备了镍-氧化镍/多孔碳纳米片（Ni-NiO/PCNs）负极材料,对比分析了氯化钠模板、退火温度和退火时间对负极材料物相组成、显微形貌和电化学性能的影响。结果表明,Ni/PCNs、Ni-NiO/C和Ni-NiO/PCNs负极材料都主要含有镍和无定型C相,且后2种负极材料还含有氧化镍相;300 ℃/4 h为Ni-NiO/PCNs负极材料适宜的退火工艺,此时Ni-NiO/PCNs负极材料中Ni-NiO粒子分散性较好且保持着三维片层结构,平均尺寸约为27 nm,Ni-NiO实现了对无定型C的包裹;退火时间过长（6 h）会使得镍粒子过氧化且发生团聚,而温度过高（400 ℃）会使得粒子以团聚为主,三维片层状结构消失。电流密度为1 A/g、循环5 000圈后Ni-NiO/PCNs负极材料的放电比容量为235 mA·h/g,此时的放电比容量约为首圈放电比容量的83.93%;Ni-NiO/C和Ni/PCNs负极材料在充放电循环过程中以及循环5 000圈后的放电比容量和容量保持率都明显低于Ni-NiO/PCNs负极材料,Ni-NiO/PCNs负极材料具有更好的循环稳定性,这主要与其具有独特的多孔三维片层结构有关。     

静磁场对ZK60镁合金组织的影响

试验发现在镁合金的凝固过程中施加静态磁场能有效细化晶粒，减小晶界化合物的厚度，同时，出现了大量细小块状化合物，这有利于提高镁合金的成形性能。