Q235焊接钢板受剪声发射时频特性分析

Q235钢板在工程中应用广泛,为了研究焊接对于Q235钢板性能的影响,开展了焊接试样和完整试样的受剪实验,利用数字声发射系统对实验过程的声发射信号进行实时采集。根据声发射计数率划分不同阶段,采用魏格纳-维尔分布,平滑伪魏格纳-维尔分布,对信号进行时频分析。实验结果表明:受剪实验中,焊接试样与完整试样的声发射特性明显不同,主要表现在受剪过程的各阶段中声发射信号能量集中的频带不同,弹性变形阶段信号时频带主要集中在80~100 k Hz附近;钢板塑性变形阶段时频带集中在100~140 k Hz范围内;焊缝塑性变形阶段,时频能量主要集中的频带范围在300~350 k Hz之间,部分能量较弱的信号分布在100 k Hz附近频段。     

孔子问答镜的文化特征提取与设计应用研究

目的将唐镜的元素运用到产品设计过程中,不仅满足目标对象对产品的多样性需求,而且也增强设计的故事性和内涵性。方法通过Kano模型用户需求分析,得到目标对象的主要需求;收集孔子问答镜的相关资料,提取孔子问答镜的显性文化特征和隐性文化特征;融合目标对象的主要需求,按照形状文法的规则演变,对提取的文化特征进行加工处理,得到可以直接应用的创意设计元素;并结合腕表设计案例对该方法进行实践验证。结论孔子问答镜文化特征提取与设计应用,既有利于提升现代人的品位,又实现了对中国传统文化的传承和创新。     

Vortex analysis and flow field optimization for the particle classifier with three rotary cages

The particle classifiers with three rotary cages have significant advantage in powder handling capacity. The flow field inside the classifiers were investigated from the perspective of vortex using Q criterion. Formation process and distribution of the vortices were intuitively exhibited. Structure of the guide cone was further optimized, and the classifying performance of the classifiers was evaluated. The results show that complex vortex structures were formed inside the classifier. The large-scale columnar vortex under the guide cone oscillates irregularly. This unwanted vortex is eliminated by extending the guide cone. The structure of the guide cone has little effect on the cut size, but the optimized guide cone with the long cylinder and cone significantly enhances the separation degree of the fine and coarse particles. The classifier obtains finer silica powder with a median size of 2.5 μm and higher Newton efficiency about 71.5%.     

一种获取Q60校色卡扫描颜色值的方法

对扫描仪进行颜色校正实验时,经常需要计算Q60校色卡被扫描后的颜色值,但校色卡的扫描颜色值不太容易获取,因为校色卡的每个色块经扫描后都包含数千个像素点,每个像素的颜色值各不相同。提出一种利用BMP图像文件属性,在VC＋＋环境下,直接编程计算Q60校色卡每一色块的扫描颜色值的方法。实验结果证明,该方法所测得的数据可靠,且简单易行,因此具有较高的实用价值。     

基于PID反馈的高Q值加速度计闭环检测电路

高Q值加速度计由于能够很好地降低热机械布朗噪声,被广泛应用于高精度低噪声检测领域,相应的闭环接口电路却成为其应用的困难之一.通过分析传感器的器件结构和动态响应,提出了一种基于PID反馈的闭环检测电路来克服传感器因高Q值造成的不利影响,改善系统的频率特性和动态响应.根据设计原理设计和测试了基于PCB板级的闭环检测电路.电...     

机器人足球赛中基于增强学习的任务分工

本文研究了机器人足球赛中利用增强学习进行角色分工的问题,通过仿真试验 和理论分析,指出文［1］中采取无限作用范围衰减奖励优化模型(infinite horizon disc ou nted model)的Q学习算法对该任务不合适,并用平均奖励模型(average reward model)对 算法进行了改进,实验表明改进后学习的收敛速度以及系统的性能都提高了近一倍．     

Solving Third Order Differential Equations with Maximal Symmetry Group

The largest group of Lie symmetries that a third-order ordinary differential equation (ode) may allow has seven parameters. Equations sharing this property belong to a single equivalence class with a canonical representative v ^′′′(u)=0. Due to this simple canonical form, any equation belonging to this equivalence class may be identified in terms of certain constraints for its coefficients. Furthermore a set of equations for the transformation functions to canonical form may be set up for which large classes of solutions may be determined algorithmically. Based on these steps a solution algorithm is described for any equation with this symmetry type which resembles a similar scheme for second order equations with projective symmetry group. Received March 9, 2000; revised June 8, 2000     

Q3接口适配系统

大量传统的电信设备由于没有提供标准的Q3接口而不能被纳入TMN系统.该文提出的Q3接口适配系统旨在解决这个问题.文章详细地阐述了Q3接口适配系统的功能组成和基本原理,并提出了实现该系统的关键技术.     

A characterization of span program size and improved lower bounds for monotone span programs

We give a characterization of span program size by a combinatorial-algebraic measure. The measure we consider is a generalization of a measure on covers which has been used to prove lower bounds on formula size and has also been studied with respect to communication complexity.?In the monotone case our new methods yield lower bounds for the monotone span program complexity of explicit Boolean functions in n variables over arbitrary fields, improving the previous lower bounds on monotone span program size. Our characterization of span program size implies that any matrix with superpolynomial separation between its rank and cover number can be used to obtain superpolynomial lower bounds on monotone span program size. We also identify a property of bipartite graphs that is suficient for constructing Boolean functions with large monotone span program complexity. Received: September 30, 2000.