Angular response of ‘pin-hole’ imaging structure measured by collimated β source

The pitch-angle distribution of energetic particles is important for space physics studies on magnetic storm and particle acceleration.A‘pin-hole’imaging structure is built with the‘pin-hole’technique and a position sensitive detector,which can be used to measure the pitch angle distribution of energetic particles.To calibrate the angular response of the‘pin-hole’imaging structure,special experiment facilities are needed,such as the particle accelerator with special design.The features of this kind of particle accelerator are:1)The energy range of the outgoing particles should be mid-energy particles(tens keV to several hundred keV);2)the particle flux should be consistent in time-scale;3)the directions of the outgoing particles should be the same and 4)the particle number within the spot should be low enough.In this paper,a method to calibrate the angular response of the‘pin-hole’imaging structure by the90Sr/90Y β source with a collimator is introduced and simulated by Geant4 software.The result of the calibration with the collimated β source is in accord with the Geant4 simulations,which verifies the validity of this method.     

城市居住区室外热环境的分析方法

针对建筑室外热环境模拟研究中对物理模型过于简化的问题,提出了一种基于数字图像分析的室外热环境模拟方法,实现了图像处理技术与数学模型的结合,有效地分析了室外热环境分布情况,并在测试结果和模拟结果的对比分析中得到证实,研究结果为室外热环境的研究方法提供了新的参考。     

Preliminary study on some properties of Co-Cr dental alloy formed by selective laser melting technique

The surface condition, some properties and ion releasing behavior of cobalt-chromium (Co-Cr) dental alloy formed by selective laser melting (SLM) technique were investigated. Before porcelain fused firing, the surface condition of the Co-Cr alloy was observed using a scanning electron microscope (SEM), and then the density and hardness were examined. After porcelain fused firing, the interface of porcelain and alloy was observed, and then the metal-ion release of the samples was tested. SLM technique provides Co-Cr alloy higher hardness than casting method. After degassing-oxidation procedure and porcelain fused firing, the interface of the alloy and porcelain showed excellent combination. Co ion was more than Cr ion released from SLM Co-Cr alloy, the amounts of Co and Cr ions were safe according to ISO security criterion. Considering the properties before and after porcelain fused sintering process, SLM technique is suitable for dental Co-Cr alloy restoration.     

三电平逆变器供电永磁同步电机直接转矩控制研究

针对临近空间飞行器电驱动系统的高效控制问题,构建一种三电平逆变器供电永磁同步电机直接转矩控制系统,以减少输出电流的谐波含量,降低转矩脉动,提升驱动系统整体效率。针对三电平逆变器空间电压矢量调制(SVPWM)实现复杂的问题,通过对大、小电压矢量选择的归纳研究,利用矢量的对称性和归一化处理方法,提出一种易于通过可编程器件实现的简洁计算方法,实现不同扇区的统一计算;构建参考矢量的复数表达形式,利用极坐标相角信息简化扇角区间判别。采用Matlab/Simulink分别构建传统两电平逆变器和三电平逆变器直接转矩控制系统进行对比分析,仿真结果验证了该算法在减小电流谐波和削弱转矩脉动方面的有效性。     

中空纤维支撑液膜萃取技术及其在药物残留检测中的应用

中空纤维支撑液膜是一种萃取新技术,具有选择性好、重现性好、节省有机溶剂等优点。介绍中空纤维支撑液膜的工作原理、结构以及萃取影响因素,就该技术在药物残留检测方面的应用进行综述。     

应用Origin软件研究非平衡电桥实验

用非平衡电压电桥测量在不同比率k值下Cu50电阻随温度变化关系.利用Origin软件,从不同角度研究非平衡电压电桥的特性,实验结果和理论值一致,k值越大,非线性误差越小,电桥灵敏度越低.     

基于Pro/E的结肠镜机器人的建模与仿真

连续型机器人是一种新型的仿生机器人。以所研制的结肠镜机器人样机为基础,基于Pro/E的运动仿真模块对结肠镜机器人单关节进行运动学分析,完成了万向环间的干涉检验,从而验证结肠镜机器人的结构设计可行。     

塔中岩溶储层地震反射地质特征及其成因机理

综合地震反射强弱及反射形态的差异,将地震反射类型划分为串珠状反射、片状反射、杂乱反射和弱反射,并对串珠状反射和片状反射进行细分.总结塔中西部下奥陶统鹰山组地震反射特征与岩溶储层对应关系,在此基础上比较每种地震反射类型所对应地质特征的差异,归纳形成四种地震反射类型的地质原因.     

一种高阻带余弦调制滤波器组的子带有源噪声控制

针对宽带有源噪声控制(ANC)系统,在采用子带自适应滤波结构时,由分析滤波器组的非理想特性及下采样原因引起的子带信号混叠问题,采用内插脉冲响应技术间接设计了一种高阻带衰减的低通原型滤波器,使得阻带能量最小化来直接消除子带信号间的混叠问题,具有较低的计算复杂度.同时,通过采用补偿误差通道延迟的方法来消除由分析滤波器组产生的延迟.仿真实验结果表明,该算法在宽带高斯白噪声和宽带有色信号下都具有较好的收敛性能,尤其对宽带有色信号.     

基于 KQML的多智能体系统建模与验证

为了保证 MAS相关属性的可满足性、有效性以及验证的高效性,提出了一种基于 KQML 通信语言的MAS建模以及能够实现自动验证相关规范的方法.设计并实现了 KQML 语言转化为完整描述状态转换关系的一组状态迁移七元组的算法,以及从七元组到多智能体模型检测工具 MCMAS输入语言ISPL的转化算法,从而实现多智能体系统的自动形式化建模,并用 MCMAS对多智能体系统规范的正确性进行验证.实验结果表明,所提出的算法不仅能够验证多智能体系统的时态规范,还能验证其特有的认知规范.