感应电机模糊预测控制策略的研究

在感应电机IM(Induction Motor)的控制中,电阻、电抗等参数对转速控制产生较大的误差影响,从而影响控制精度和动态响应速度.基于感应电机的数学模型,将模糊逻辑系统引入预测控制.针对异步电机的强耦合特性,提出模糊模糊预测控制的方法,并用模糊预测控制的方法设计了高性能的转速控制器.并借助DSP实验平台,将系统模型下载到实时硬件中进行在线仿真,实验结果表明,所设计的控制器在提高速度控制的快速性和抗干扰能力上得到满意的效果.     

Collection and Management of Shop-floor ControllerData

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吃饺子过年

过年一定要吃饺子.北方有一句俗语是"好活不如躺着,好吃不如饺子".饺子一直是北方人不可缺少的年夜饭.但是好吃却不好做.现在我们就把流行于北方的几样饺子的做法教给大家,希望南方的朋友在除夕也能吃上美味的饺子.     

Spike-timing-dependent synaptic modification induced by natural spike trains

The strength of the connection between two neurons can be modified by activity, in a way that depends on the timing of neuronal firing on either side of the synapse. This spike-timing-dependent plasticity (STDP) has been studied by systematically varying the intervals between pre- and postsynaptic spikes. Here we studied how STDP operates in the context of more natural spike trains. We found that in visual cortical slices the contribution of each pre-/postsynaptic spike pair to synaptic modification depends not only on the interval between the pair, but also on the timing of preceding spikes. The efficacy of each spike in synaptic modification was suppressed by the preceding spike in the same neuron, occurring within several tens of milliseconds. The direction and magnitude of synaptic modifications induced by spike patterns recorded in vivo in response to natural visual stimuli were well predicted by incorporating the suppressive inter-spike interaction within each neuron. Thus, activity-induced synaptic modification depends not only on the relative spike timing between the neurons, but also on the spiking pattern within each neuron. For natural spike trains, the timing of the first spike in each burst is dominant in synaptic modification.     

Influence of stress on the stray field signals of ferromagnetic materials

To investigate the influence of stress alone on the stray field signals of ferromagnetic materials,the static tensile tests of 0.45%C steel and 45CrNiMoVA steel flat-shaped specimens were performed on an MTS810 hydraulic testing machine. H_p(y) signals,the normal component of spontaneous stray field,were measured during the testing process by an EMS-2003 metal magnetic memory diagnostic apparatus cooperated with a non-magnetic electric control displacement instrument. Fracture and microstructure were observed by a scanning electronic microscope and a transmission electron microscope,respectively. The relationships between axial applied stress or residual stress measured by X-ray diffraction method and H_p(y) were analyzed. The results indicate that some regular pattern of the magnetic curve is displayed only between applied stress and stray field signals. The magnetic ordering process stops due to dislocation pinning magnetic domain structure,and H_p(y) value unvaried nearly with applied load increasing in the plastic deformation stage.     

高温高压岩芯多参数测量仪器的研制

介绍了SCMSB2型高温高压岩芯多参数测量仪器所测量的参数范围、测试原理、测试方法、系统的硬件和软件结构。该仪器可以在模拟地层温度(室温～150℃)和压力(1～90MPa)的条件下完成不同渗透率级别、直径为2.5cm岩芯的气体孔隙度、渗透率、岩芯电阻率与地层水电阻率、纵横波波速测量、油水相对渗透率等参数的测量,还可以进行“七敏”以及岩芯杨氏弹性模量与抗压强度等参数的测量。实际应用表明该仪器具有操作简单、自动化程度高、测试参数多、测量时间短、重复性好等优点。     

太原市初中学校室内外环境与儿童不良建筑综合征的相关性

为了解初中学校儿童不良建筑综合征(sick building syndrome,SBS)、哮喘等疾病的发病率以及室内外环境污染水平和疾病的相关性,在山西省太原市城区初中学校开展了一项横断面研究.本研究采取整群抽样的方法,随机选取10所学校,问卷调查共发放2209份,其中有效问卷1993份(应答率为90.2%).参与调查的学生平均年龄为13岁(年龄范围11~15岁),其中女孩占49.3%.问卷内容包括SBS症状、哮喘及其他相关疾病的患病情况,SO2,NO2和O3环境影响因素的测量通过被动吸附采样,以及多因素Logistic回归分析疾病与环境因素的相关性.结果显示,儿童鼻黏膜炎(17.6%)、鼻塞(16.4%)、喉咙干燥(14.9%)、疲乏(20.7%)等症状患病率较高.室内NO2与鼻黏膜炎、喉咙干燥、头疼、恶心、湿疹症状呈现正相关(比对比(OR)和95%置信区间(CI)分别为1.16,1.01~1.33;1.16,1.00~1.34;1.24,1.02~1.52;1.30,1.04~1.63;1.86,1.19~2.90).室内O3仅与医生诊断哮喘呈现正相关(1.36,1.02~1.80).室内SO2几乎与所有儿童SBS的症状呈现显著性相关.此外,室内与室外浓度的比值也与部分SBS症状正相关.本研究表明儿童不良建筑综合征与教室室内外环境相关.     

限域于三维多孔碳的超细纳米尺度Cu2Sb合金用于钠离子和钾离子电池负极

Ultrafine nano-scale Cu₂Sb alloy confined in a three-dimensional porous carbon was synthesized using NaCl template-assisted vacuum freeze-drying followed by high-temperature sintering and was evaluated as an anode for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs). The alloy exerts excellent cycling durability (the capacity can be maintained at 328.3 mA·h·g?1 after 100 cycles for SIBs and 260 mA·h·g?1 for PIBs) and rate capability (199 mA·h·g?1 at 5 A·g?1 for SIBs and 148 mA·h·g?1 at 5 A·g?1 for PIBs) because of the smooth electron transport path, fast Na/K ion diffusion rate, and restricted volume changes from the synergistic effect of three-dimensional porous carbon networks and the ultrafine bimetallic nanoalloy. This study provides an ingenious design route and a simple preparation method toward exploring a high-property electrode for K-ion and Na-ion batteries, and it also introduces broad application prospects for other electrochemical applications.     

塬堡黄土剖面记录的末次冰期气候不稳定性

选用西部黄土高原高分辨率的临夏塬堡黄土剖面,将剖面平均粒径和〉40μm粒级含量气候代用指标作为气候要素,运用统计分析应用中移动平均的方法提取剖面记录的突发事件,发现末次冰期黄土不仅记录了能与高纬北大西洋和格陵兰地区遥相呼应的突发事件,且还记录了除Heinrich和YD事件以外的突发事件达15次之多．表明气候突变是黄土高原末次冰期气候变化的主旋律,抑或还说明普遍被国内外学者认同的气候突变机制北大西洋热量传输、大气环流理论和低纬海洋与大气作用理论有待商榷,从末次冰期东亚冬季风气候演变特征及与外围区域气候的联系入手或许能有所突破．同时,通过对Heinrich和YD事件特征的详细研究,尝试性地定义了黄土记录的突发事件：即若平均粒径存在一个高粒度、高碳酸盐、高亮度值,而低磁化率、低红度值和黄度值的事件,且该事件在平均粒径和〉40μm的粒级含量曲线上,相邻峰谷间的变化幅度大干3．4μm,且〉40μm的粒级含量大干2．0μm,而其变化时间小于500a,就可视为一个突发事件．