大卸载力铠装永磁轴承设计分析

飞轮储能轴系采用非接触磁轴承,卸载轴系80%~90%重量,以降低下支承磨损和功耗。提出铠装钕铁硼永磁轴承设计方法,并应用于400 k W飞轮储能工程样机的磁轴承设计。该设计构型简单,单磁环被包在磁轭中,转子部分无永磁材料,规避振动和散热问题。磁环采用扇形磁瓦拼接,可满足大卸载力需求,其磁场不均匀性对轴向卸载力影响可忽略。工作间隙附近,轴承吸力与间隙大小关系近似线性化。工作间隙中磁轭面积约是磁环面积2倍时,轴承获得最大吸力。高效设计流程方法使磁环体积减少24.4%。给出了不同转速下的轴承最大卸载力设计参数。     

神经网络分数阶PI~μD~λ在压电叠堆控制中的应用

为了克服压电叠堆的迟滞特性,实现压电叠堆的精确控制,建立了压电叠堆控制系统,研究了该系统所用到的神经网络、分数阶微积分等算法。首先,搭建了采集压电叠堆位移数据的硬件系统,并对含有噪声的位移数据进行了滤波处理;利用径向基函数(RBF)神经网络对压电叠堆建模,得到了模型参数。然后,利用RBF神经网络建模得到的Jacobain信息来整定分数阶PI~μD~λ控制器中的参数对压电叠堆进行控制。最后,与RBF整数阶PID对压电叠堆的控制效果进行了对比。结果显示:RBF建模误差仅为位移实测数据的0.22%,RBF神经网络分数阶PIμDλ控制系统输出稳定,很好地跟随了给定。得到的结果表明RBF神经网络分数阶PI~μD~λ控制器控制性能良好,在压电叠堆的控制中比RBF整数阶PID控制器表现得更加稳定、精确。     

Fabrication of flexible interdigitated μ-electrodes (FIDμEs) for the development of a conductimetric immunosensor for atrazine detection based on antibodies labelled with gold nanoparticles

The present paper describes a simple and low-cost method for the fabrication of mechanically flexible interdigitated μ-electrodes (FIDμEs) and its application as immunosensor.FIDμEs consist of two coplanar non-passivated interdigitated metallic μ-electrodes supported on a flexible transparent substrate, polyethylene naphthalate (PEN). Bioreagents deposition on PEN substrates becomes possible by depositing SiO₂ on the electrodes surface (fingers and inter-digits space).These FIDμEs were successfully applied for the development of a selective conductimetric immunosensor for the quantification of atrazine residues. The immunosensor has been demonstrated for detection of small amounts of atrazine, thanks to the use of immunoreagents specifically developed to detect this pesticide.The detection method applied is based on the use of antibodies labelled with gold nanoparticles. The presence of these particles amplifies the conductive signal; hence the immunosensor response was quantified using simple and inexpensive DC measurements.Immunochemical detection of the concentrations of atrazine is achieved by a competitive reaction which occurs before the inclusion of the labelled antibodies.The immunosensor shows limits of detection in the order of 2-3 μg L⁻¹, far below the maximum residue level (50 μg kg⁻¹) established by EU for residues of atrazine as herbicide in the wine grapes and other foodstuff products.     

非稠合型硼烷和碳硼烷的新电子计数规则

有许多非稠合型闭式硼烷和碳硼烷无法应用Wang和Schleyer的6m+2n电子规则.作者根据实验事实和量子化学计算结果,提出了一个适用于非稠合型硼烷和碳硼烷的电子计数新规则,它适用于各种类型非稠合型闭式硼烷和碳硼烷,扩展了6m+2n电子规则的应用范围.同时该规则对于非稠合型非闭式硼烷和碳硼烷也完全适用,应用范围比Wa...     

CHINALCO Seek Rare Earth Project in Guangdong

【正】CHINALCO and the Qingyuan municipal government in Guangdong will sign a framework agreement at the beginning of 2011 to jointly tap local rare earth resource...     

锁口钢管桩围护仿真分析

以某深基坑开挖支护为工程背景,建立锁口钢管桩围护三维有限元模型。基于盾恩法确定了钢管桩嵌入深度,采用库仑经典土压力公式计算坑外主动土压力,应用＂m＂法计算坑底被动土压力。通过仿真计算得出各控制工况最大应力、变形的数值及发生位置,确定整个施工阶段的控制技术指标及参考值。     

大型磷酸贮罐底部结构施工方案的比较

介绍了大型磷酸贮罐底板、工字钢及土建基础之间的结构关系,采用贮罐底部结构施工方案对比,优选出安全可靠、造价经济、维修方便的施工方案。优选方案不仅适用于大型磷酸贮罐(公称容积大于1000 m3),而且对其它采用条形基础的贮罐均具有参考价值。     

Symmetric and symplectic exponentially fitted Runge–Kutta–Nyström methods for Hamiltonian problems

The construction of symmetric and symplectic exponentially fitted modified Runge–Kutta–Nyström (SSEFRKN) methods is considered. Based on the symmetry, symplecticity, and exponentially fitted conditions, new explicit modified RKN integrators with FSAL property are obtained. The new integrators integrate exactly differential systems whose solutions can be expressed as linear combinations of functions from the set { exp(± iωt)}, ω > 0, i² = −1, or equivalently from the set { cos(ωt), sin(ωt)}. The phase properties of the new integrators are examined and their periodicity regions are obtained. Numerical experiments are accompanied to show the high efficiency and competence of the new SSEFRKN methods compared with some highly efficient nonsymmetric symplecti EFRKN methods in the literature.     

基于STM32的工业通用控制器的研究与实现

设计的基于嵌入式微处理器、可组态的工业通用控制器支持以控制系统图形化编程为基础的过程控制。在论述控制器硬件整体架构的基础上,详细分析了软件设计中,组态序列解析方法、多任务之间的同步及通信协议状态转换等影响系统实时性和鲁棒性的因素,并提出有效的解决方法。     

40mT梁现场预制施工技术

通过闻垣高速LA10合同段车家沟大桥40mT梁的现场预制实例，叙述了该大桥在施工过程中钢筋的绑扎、模板的安装、混凝土的浇筑、预应力张拉和孔道压浆等主要施工方法，并总结了一些施工质量管理措施，为类似工程积累了宝贵的经验。