金属垂直安定面的后向散射分析

采用射线跟踪和等效电流等方法计算金属垂直安定面的后向散射场和后向散射截面积(RCS)。对TM入射和TE入射在不同的入射角下求得数值结果。仔细分析了外形对后向RCS的影响,并提出压缩后向RCS的措施。     

And I Still Love Them: On Touching Loss

In this article, the author performs a re‐membering practice that incorporates a relational materialist theory. It traces the disturbances that follow in the wake of three deaths in her family. Written in an autoethnographic voice, the article is a polyphonic composition of the narrative therapy approach of re‐membering entangled with the spacetimematter of silence, speaking, sitting, staying, presence, absence, loss of momentum, dreams, trees, books, cardiac pace‐makers, writing, breath, ashes, murmuring, suffering. Thus, the dispersed agencies of bodies, human and non‐human, reinvigorate a linguistic practice and the author's personal and professional life.     

光盘扫描高斯光束的研究

讨论了扫描光束对高斯参数扫描光点强度分布的影响；给出了高斯参数与中心峰值强度及光点直径的定量关系；展示出焦平面上的三维光强分布图；提出了光盘存贮中高斯参数的选择依据；有效利用无能，获得高性能扫描光点。     

激光喷丸参数对304不锈钢表面性能的影响

为了研究喷丸能量密度和喷丸搭接率等工艺参数对304不锈铜表面性能的影响,采用激光喷丸冲击强化的方 法,用X射线衍射方法检测了试样表层的相组成,用显微硬度计测量了试样表层的显微硬度。结果表明,304不锈铜经 过激光喷丸处理后,表层组织没有发生明显的马氏体相变,表层硬度得到提高,随着喷丸能量密度和搭接率的增加,表层 硬度有增大的趋势。     

熔石英损伤修复形貌对光场调制的标量衍射理论研究

熔石英表面损伤对于传输光场以及光学系统有诸多不利影响,CO2激光修复技术可以提高损伤阈值,有效地消除或减轻损伤对光路的影响.本文利用数学仿真工具MATLAB和标量衍射理论针对大尺寸高斯以及圆锥类型修复形貌(非蒸发和蒸发修复)对光调制的影响进行相应的模拟仿真计算,获得修复形貌对传输光场的调制作用以及被调制光场在修复元件下游的衍射传输情况.本研究以355nm激光为激发波长进行相应的仿真计算,分别探讨了两种修复形貌对入射光场调制的异同以及该光场被调制后对下游光传输的影响.结果表明,CO2蒸发与非蒸发技术对损伤修复形貌的光场传输有着不同的影响,传输光场的调制度随着形貌的宽深比(半径R-深度L)不同而变化.因此,适当控制修复形貌及尺寸可在有效提高熔石英激光损伤阈值的同时避免调制光强过大对下游光学元件的再次损伤,以保证激光装置稳定运行.     

等腰三角形孔的夫琅和费衍射研究

衍射是光波动性的重要特征之一，论文在相关理论研究的基础上，推导出等腰三角形孔的夫琅和费衍射的一维积分表达式，通过分析得出这种孔的衍射图样的特点，以及在衍射图样中，边的形状和角的存在与否对其衍射图样有着很大的影响的结论。     

铅蓄电池正极材料的X射线衍射分析

本文用X射线衍射法对铅蓄电池正极活性材料二氧化铅进行了结构分析。结果表明:正极的二氧化铅同时存在二种不同的晶体结构。正方晶系的β—PbO_2主要分布在电极表面,针方晶系的α—PbO_2则分布在电极内部。如果将块状电极碾磨测量,α—PbO_2与β—PbO_2的含量几乎是相等的。     

临床X射线相衬成像研究进展

X射线相衬成像在提高人体软组织成像的衬度分辨率及空间分辨率研究中具有潜在优势,是一项有着广阔发展前景的技术。它利用空间相干X射线投过物体后携带的相位信息进行成像,在临床上适用于软组织物体,可以减少吸收剂量,进而减轻病人的辐射损伤。本文详述了当今几种典型的X射线相衬成像方法,包括X射线干涉相衬,衍射增强相衬以及类同轴相衬的成像原理以及发展历程。通过对比表明了几种成像方法的优缺点。最后对临床X射线相衬成像有待解决的问题作了分析。     

‘The past was never simply there to begin with and the future is not simply what will unfold’: a posthumanist performative approach to qualitative longitudinal research

In this article I argue that in their current genealogical and philosophical configuration, qualitative longitudinal research (QLR) practices – and a wider regime of knowledge, ethical, moral, legal, technological, political and economic practices with which they are entangled – embed and enact representational assumptions in which the realities being investigated – time, change and continuity; the past, present and future – are taken as ontologically given and independent of these QLR (and wider) practices. My approach is to conceptualize QLR practices along nonrepresentational lines, through a philosophical framework that is able to materialize the constitutive effects of QLR (and wider) practices on the objects of study and knowledges produced. For this, I turn to Karen Barad’s posthumanist performative metaphysics – ‘agential realism’ – a framework that embodies and enacts a non-classical ontology in which entities are seen as constituted through material-discursive practices. On this account, QLR (and wider) practices are understood as an ineliminable and constitutive part of the realities they help bring into being.     

口径面天线辐射近区场强计算

利用一种新的天线口径场积分的近似算法和几何绕射理论,并结合实际工程中天线的计算实例,对口径面天线的近区场进行计算,提高了计算的速度,又保证了计算结果的准确性。结果表明,该方法是处理天线辐射近区场强以及电磁兼容问题的一种有力工具。