A method based on diffraction theory for predicting 3D focusing performance of compound refractive X-ray lenses

A method based on the diffraction theory for estimating the three-dimensional (3D) focusing performance of the compound refractive X-ray lenses is presented in this paper. As a special application, the 3D X-ray intensity distribution near the focus is derived for a plano-concave compound refractive X-ray lens. Moreover, the computer codes are developed and some results of 3D focusing performance for a compound refractive X-ray lens with Si material are shown and discussed.     

A theoretical method based on Fourier spectrum analysis for the focusing performances of the X-ray compound refractive lenses

It is important to predict the intensity distribution in focusing plane for designing the X-ray compound refractive lenses. On the basis of analyzing the structure of X-ray compound lenses and comparing it with Praunhofer diffraction system, it is concluded that the X-ray focusing system can be regarded as a kind of Praunhofer diffraction system. Therefore, a method based on Fourier spectrum analysis is presented to predict the intensity distribution in the focusing plane for the X-ray lenses. A brief analysis on the relationship between the parameters of X-ray lenses and their focusing performance is also given in this paper.     

一种解决调频连续测距中测距模糊方法

通过对锯齿调频连续测距系统的差频信号分析可知,由于观测时间的随机性导致同一距离上对应两个不同的差频频率。对差频信号进行时域和频域分析发现,利用两次混频的方法能够解决这种测距模糊问题,使信号处理单元的输出信号频率和距离一一对应。利用仿真软件,得到信号处理过程中的时频关系曲线,验证了这种信号处理方法的有效性。     

用全反射X荧光技术分析釉药粉末

１引言在微量痕量元素分析方面，全反射Ｘ荧光（ＴＸＲＦ）分析技术被认为是八十年代发展起来的最有竞争能力的分析手段，在原子谱仪中处于领先地位。我们从八十年代开始从事ＴＸＲＦ的研究，并于１９９３年自制出一台双激发源双光路全反射Ｘ荧光分析装置。几年来我们在许多领域里开展了应用研究。对水、油、头发、动物、古铜器、矿石粉、高纯材料、人工晶体等进行了分析实验。釉药是生产陶瓷的重要原料，需要好的配方并进行质量控制。但是，釉药粉末是多种原料的混合物，含有Ｓｂ、Ｚｒ、Ｔｉ、Ａｓ等多种元素，难以消解，不易配成均匀的溶…     

Design and fabrication of one-dimensional focusing X-ray compound lens with Al material

A method based on Fourier spectrum analysis for predicting the performances of the X-ray compound lenses is briefly introduced, the theoretical result obtained is the same as that of Fresnel-Kirchhoff approach. A kind of technique named moulding is developed for fabricating the one-dimensional (1D) compound X-ray lens with Al material and the fabrication process is presented. In addition, a two-time coating method is used to improve the numerical apertures of the compound lenses. Furthermore, the focusing performance of the Al compound X-ray lens under the high energy X-rays is measured.     

抛物面型X射线组合折射透镜聚焦性能的理论与实验研究

结合衍射理论和矩阵光学方法得出抛物面型X射线组合折射透镜的光学性能指标(包括其焦距的严格表达式、薄透镜近似的判定准则、透过率和有效孔径,以及极限聚焦光斑尺寸等).采用X射线深度光刻技术实际制作了PMMA材料抛物面型X射线组合折射透镜并给出了工艺测试结果.最后在北京同步辐射装置(BSRF)上,实际构建了基于3种不同结构参数的PMMA材料抛物面型X射线组合折射透镜的微束聚焦实验系统.并实际测试了其聚焦性能,均获得了良好的聚焦效果,给出实测结果并对实测结果进行了分析和讨论.     

鱼类Ⅱ型抗冻蛋白-冰-水复合体系的理论模拟研究

对鱼类Ⅱ型抗冻蛋白冰晶组成的复合体系在真空条件下进行理论模拟计算的基础上,构建出鱼类Ⅱ型抗冻蛋白冰溶剂(水)的三元复合体系.经过350 ps的动态模拟,研究了溶剂化效应对蛋白冰相互作用体系的影响.通过分子力学及半经验量子力学的计算,进一步研究蛋白与冰晶的相互作用性质,结果表明溶剂化效应具有不容被忽视的重要作用.     

2,9,16,23-四-[4-二甲氨基苯氧基]锌酞菁的合成和分子内光致电荷转移反应的研究

光敏电荷转移是近年来十分活跃的研究领域,人们设计了各种电子给体和电子受体用共价键相连结的化合物,如:卟啉电子给体,醌^[1]、硝基苯、甲基紫精作为电子受体,模拟自然界的光合作用。     

烷氧基取代金属酞菁固态薄膜光谱及结构的研究

本文选用一种烷氧基取代的金属酞菁化合物,溶解旋涂于玻璃基板上,分别经有机溶剂处理和加热处理,发现都可以使吸收光谱范围向长波方向拓宽。X-射线衍射研究表明:经上述方法处理后都可使染料分子的聚集程度发生变化,堆砌方式由微晶型向晶型结构转变,高分辩率扫描电镜观察进一步证实了上述结果。     

非均质和各向异性土质浅埋隧道支护力研究

针对土体的非均质和各向异性,以土质浅埋隧道为例,采用极限分析上限法和可靠度方法研究隧道支护力的大小.结果表明,土体非均质和各向异性对支护力的影响程度取决于隧道的埋深.当埋深小于15m时,围岩的自稳能力较差,土体非均质和各向异性的影响不能明显地体现出来,支护力主要随埋深的增大而增大;当埋深大于20 m时,围岩的自稳能力较强,支护力随土体非均质和各向异性的增大发生明显变化,埋深越大,土体非均质和各向异性对支护力的影响越强.可靠度研究表明,非均质和各向异性参数的分布及变异系数的大小对支护力的影响较大,对数正态分布时影响更为明显.建议在土质浅埋隧道设计时,务必考虑土体的非均质和各向异性,防止保守支护增加工程成本或支护力不足引起隧道坍塌.