纸页受力微损伤演化过程的声发射及多元统计特征

纸页受载后的损伤断裂行为涉及其使用性能,对其损伤断裂过程的研究不仅有助于揭示纸页破坏行为的物理本质,而且有助于对纸页质量及其生产、加工工艺作出更加科学合理的评定。本文基于声发射(Acoustic Emission,AE)实验研究纸页内部微损伤演化过程,给出了评估纸页宏观损伤断裂性能的定量描述方法。首先,根据AE信号与微损伤事件之间存在本质上的关联性,通过采集和观测纸页试样受载过程中的AE信号来研究纸页损伤断裂的基本特征;其次,针对所采集AE信号的数据量大、蕴含信息丰富导致数据分析和处理困难的特点,本文采用多元随机变量的分析方法。利用概率熵和Andrews曲线法等统计分析手段对AE数据展开研究分析,并最终利用一条损伤状态轨迹曲线实现了对纸页微损伤演化过程的完整宏观描述。结果表明,纸页微损伤演化过程呈现明显阶段性变化特征;Andrews曲线的聚类结果有效地区分了不同损伤阶段的相似性和差异性,同时,不同损伤阶段中纸样的微观形貌观测提供了实验性的证据。本文以一种典型的牛皮箱板纸为试件,验证了上述方法的有效性。     

滑动摩擦力作用下弹簧振子的振动

对在粗糙水平面上作振动的弹簧振子进行研究,探讨该弹簧振子最后停止的位置,估算了弹簧振子的振动总次数,得出弹簧振子的相轨迹.     

C (3P)+NO (X2)CN (X2+)+O (3P) 反应的矢量相关研究

采用准经典轨线方法研究了三个不同碰撞能下,反应C (3P)+NO (X2)CN (X2+)+O (3P) 在Nyman等拟合的两个势能面（2A" 和 2A'）上反应物与产物之间的矢量相关. 结果表明在两个势能面上产物的转动角动量矢量不仅取向,而且沿着y轴垂直于散射平面定向,产物的角动量定向依赖于碰撞能和势能面. 同时,计算的四个重整化极化依赖微分截面显示产物在三个散射角被强烈极化,这与在两个势能面上的三个过渡态有关.     

The optimal path of piston motion for Otto cycle with linear phenomenological heat transfer law

An Otto cycle engine with internal and external irreversibilities of friction and heat leakage, in which the heat transfer between the working fluid and the environment obeys linear phenomenological heat transfer law [q ∝△(T -1)], is studied in this paper. The optimal piston motion trajectory for maximizing the work output per cycle is derived for the fixed total cycle time and fuel consumed per cycle. Optimal control theory is applied to determine the optimal piston trajectories for the cases of with and w...     

Regarding the 21S0 and 23S1 multiplets

<正>This paper discusses the masses and possible members of 2¹S₀ and 2³S₁ meson multiplets in the framework of meson-meson mixing and Regge phenomenology.For the 2¹S₀ meson nonet,K^*（1460） may be the observed state of the 2¹S₀ isodoublet with a mass of 1400 MeV and the mass ofω（1420） is 1412 MeV.For the 2³S₁ meson nonet,K^*（1410） seems too light to be the 2³S₁ ns member.The fact that the agreement between the present findings and those given by experiments and other different approaches is satisfactory implies that the assignments in this paper may be reasonable.     

The characteristics of O＋HD （v = 0, j = 0） reaction dynamics

The analytical potential energy function of HDO is constructed at first using the many-body expansion method.The reaction dynamics of O+HD(v = 0,j = 0) in five product channels are all studied by quasi-classical trajectory(QCT) method.The results show that the long-lived complex compound HDO is the dominant product at low collision energy.With increasing collision energy,O+HD → OH+D and O+HD → OD+H exchange reactions will occur with remarkable characteristics,such as near threshold energies,different reaction probabilities,and different reaction cross sections,implying the isotopic effect between H and D.With further increasing collision energy(e.g.,up to 502.08 kJ/mol),O+HD → O+H+D will occur and induce the complete dissociation into single O,H,and D atoms.     

基于弹道的紫外告警系统探测方位角及规避时间仿真分析

提出基于比例导引规律的弹道三维仿真方法,利用弹道仿真法计算了紫外告警系统的探测方位角以及规避时间,分析了来袭导弹距离、威胁方向对探测方位角的和规避时间的影响。结果表明:当导弹在一定距离外,探测方位角随导弹距离的减小而增大、随威胁方向的增大先增大后减小,并且飞机以某威胁方向飞行时,告警系统对某距离范围内的导弹探测方位角几乎没有变化,规避时间随威胁方向的增大而减小。     

Investigation of a method to calculate spontaneous radiation spectra from relativistic electrons in undulators

Undulators are key devices to produce brilliant synchrotron radiation at the synchrotron radiation facilities. In this paper we present a numerical computing method, including the computing program that has been developed to calculate the spontaneous radiation emitted from relativistic electrons in undulators by simulating the electrons＇ trajectory. The effects of electron beam emittance and energy spread have also been taken into account. Comparing with other computing methods available at present, this method has a few advantages with respect to several aspects. It can adopt any measured or arbitrarily simulated 3D magnetic field and arbitrary electron beam pattern for the calculation and it＇s able to analyze undulators of any type of magnetic structure. It＇s expected to predict precisely the practical radiation spectrum. The calculation results of a short period in-vacuum undulator and an Elliptically Polarized Undulator （EPU） at Shanghai Synchrotron Radiation Facility （SSRF） are presented as examples.     

弹道相机图像分析系统与普通扫描仪精确标定

研制该系统的目的是对弹道干板进行数字化、高精度、高自动化的判读,代替传统上低效率的人工判读方法。该系统使用普通平板扫描仪将弹道相机拍摄到的干板图像进行数字化并对扫描图像进行高精度的标定和修正,再利用数字图像处理技术对于板图像进行分析判读。着重叙述了用分布于待测图像四周的标准正交网络对包括待测图像在内的全场进行标定和修正的方法及实验结果。经过本方法标定和修正后,扫描图像几何标准偏差在2～3μm以内。该判读系统及所用到的扫描仪标定方法,实现了弹道干板的数字化、自动化的高精度判读,使普通扫描仪可用于精度要求极高的工程测量。     

旋流燃烧室内颗粒运动的数值模拟

本文应用流体相湍流脉动速度大小和方向均具有随机性的颗粒相随机轨道模型,对有直流一次风和旋流二次风的旋流燃烧室内的颗粒运动进行了数值模拟。得到的颗粒相轴向总质量流通量、轴向与切向速度分布与实验测量数据相符合,并比 Gosman 颗粒随机轨道模型的模拟结果有一定的改进。