排序方式: 共有46条查询结果,搜索用时 31 毫秒
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A. Simon Z. Kntor 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2002,190(1-4):351-356
The formation and deposition of particulates by pulsed laser deposition of Si1−xGex semiconductor alloy thin films are discussed. Using Rutherford backscattering spectrometry with micrometer lateral resolution (micro-RBS) the film composition was measured with high accuracy, even in the presence of particulates with a high areal density of 20,000–30,000 particulates per mm2. We show that on impact of a particulate, the part of the thin film which is already deposited probably melts and its Ge content segregates to the surface. 相似文献
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α粒子微束定点照射--细胞的放射生物学效应及精确性分析 总被引:2,自引:0,他引:2
进行微束试验的关键是能够精确地控制照射的粒子数和将粒子准确地射入受照射位点.该研究通过对哥伦比亚大学单粒子微束装置在精确性、准确性以及各项指标的分析发现该装置可精确地控制照射粒子数,精确率为98.4%.同时,它可将α粒子准确地射入受照射位点,束半径为34,达到设计4的标准.在对细胞特定位点如细胞质照射上,粒子击中细胞质至少一个位点的概率为90%,在这一过程中的偶然核击中率,对大多数照射剂量(8个粒子)均小于0.8%.应用该微束装置的放射生物学研究发现单个α粒子仅导致大约20%的致死率,其存活率曲线类似于用常规照射获得的平均粒子存活曲线.诱变试验首次证实单个α粒子在AL细胞的CD59基因位点可诱导出比对照高出3倍数量的诱变子,诱变率随粒子数的增加而增加.这一结果不同于常规照射中,诱变率在高剂量照射后下降的结论. 相似文献
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该文研究了微束系统中的细胞图像处理问题。着重从微束装置的实际情况出发,对不同于一般图像处理的微图像处理进行了介绍,详细讨论了整个图像处理的过程,并探讨了微图像处理在整个微束计算机控制系统中的重要作用。 相似文献
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Hiroshi Kajioka 《Polymer》2010,51(8):1837-6705
The orientation of lamellar crystals in non-banded spherulites of it-polystyrene and it-poly(butene-1) was investigated by microbeam X-ray diffraction. The two-dimensional intensity map of diffraction enables us to examine the local orientation of lamellar crystallites in the non-banded spherulites. The obtained results indicated the re-orientation of crystallites in non-banded spherulites and confirmed our previous observation on the anisotropic birefringence of a group of crystal stacks by polarizing optical microscopy. 相似文献
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Kunikazu Ishii Natsuko FujitaHidemi Ogawa 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(9):1026-1028
We have developed a simple Rutherford backscattering spectroscopic (RBS) method to analyze sample depth profiles in air. To avoid excessive energy loss of projectile ions in air, we have used a 3 MeV proton beam extracted into air with a metal capillary. Using this capillary, we were able to extract a sufficiently large proton beam current to perform in-air RBS and in-air PIXE without requiring any window, such as a thin film, between a vacuum chamber and air. We have validated our technique by analyzing the depth profiles for Au foils of various thicknesses, 0.25, 0.75, and 2.5 μm. A comparison of the experimental results with a simple theoretical calculation indicates that this technique is useful for analyzing the depth profile of any specimen in air. 相似文献
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Guanghua Du Bernd E. FischerKay-Obbe Voss 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(20):2312-2316
To study the fast intracellular calcium response after ion irradiation in living mammalian cells, a live cell calcium imaging set-up was constructed at the targeted cell irradiation facility at GSI. This work introduces the live cell calcium imaging system, shows its performance, an example of the ratio-metric calcium measurement and its application to on-line study calcium response to targeted ion irradiation in human cells. 相似文献
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The effects of flow-altering inserts and mold cavity geometry on the mechanical properties of an injection molded liquid crystalline polymer were studied to produce parts with properties approaching macroscopically isotropic state. By inserting fine metal mesh barriers to the gates of the mold cavities, a large number of highly oriented microstreams are produced. After their creation these highly oriented streams of differing flow vectors intertwine and this texture remains reasonably intact even after substantial shearing and extension history imparted on them during ensuing flow into the cavity. This method is effective in the interior away from the skin regions formed under the shearing flow during injection. The local molecular orientation was determined using a matrixing microbeam WAXS technique that allows precision movement of the sample in the microbeam X-ray. Samples produced with the 1.0 mm2 mesh showed large variations in the local symmetry axis with respect to the machine as measured by microbeam X-ray diffraction incrementally from the edge to the core of the parts. In comparison, samples with no mesh insert showed only gradual changes in the tilt angle (angle between local symmetry axis and flow direction). The modulus and tensile strengths of all samples with the 1.0 mm2 mesh inserts were found to approach virtual global mechanical isotropy. 相似文献
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In this paper, the electrostatic pull-in behavior of two elastic parallel fixed–fixed and cantilever microbeams in microelectromechanical systems (MEMS) are investigated. The nonlinear electrostatic equations are considered due to some important effects including: residual stresses, fringing field and axial stresses. Various residual stresses in two elastic parallel fixed–fixed models are considered. Step by step linearization method is used to solve the equations. The numerical results reveal that the step by step linearization method is highly efficient, and it is the easiest one to calculate the pull-in voltage. In the proposed models, the pull-in voltages are considerably decreased when compared to the pull-in voltages of simple fixed–fixed and cantilever models. 相似文献