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ALFIO TORRISI PRZEMYSLAW WACHULAK ŁUKASZ WĘGRZYŃSKI TOMASZ FOK ANDRZEJ BARTNIK TOMÁŠ PARKMAN ŠÁRKA VONDROVÁ JANA TURŇOVÁ BARTŁOMIEJ J. JANKIEWICZ BARTOSZ BARTOSEWICZ HENRYK FIEDOROWICZ 《Journal of microscopy》2017,265(2):251-260
We report on a very compact desk‐top transmission extreme ultraviolet (EUV) microscope based on a laser‐plasma source with a double stream gas‐puff target, capable of acquiring magnified images of objects with a spatial (half‐pitch) resolution of sub‐50 nm. A multilayer ellipsoidal condenser is used to focus and spectrally narrow the radiation from the plasma, producing a quasi‐monochromatic EUV radiation (λ = 13.8 nm) illuminating the object, whereas a Fresnel zone plate objective forms the image. Design details, development, characterization and optimization of the EUV source and the microscope are described and discussed. Test object and other samples were imaged to demonstrate superior resolution compared to visible light microscopy. 相似文献
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PRZEMYSLAW LITEWKA JERZY RAKOWSKI 《International journal for numerical methods in engineering》1997,40(14):2629-2652
The plane two-node curved beam finite element with six degrees of freedom is considered. Knowing the set of 18 exact shape functions their approximation is derived using the expansion of the trigonometric functions in the power series. Unlike the ones commonly used in the FEM analysis the functions suggested by the authors have the coefficients dependent on the geometrical and physical properties of the element. From the strain energy formula the stiffness matrix of the element is determined. It is very simple and can be split into components responsible for bending, shear and axial forces influences on the displacements. The proposed element is totally free of the shear and membrane locking effects. It can be referred to the shear-flexible (parameter d) and compressible (parameter e) systems. Neglecting d or e yields the finite elements in all necessary combinations, i.e. curved Euler–Bernoulli beam or curved Timoshenko beam with or without the membrane effect. Applying the elaborated element in the calculations a very good convergence to the analytical results can be obtained even with a very coarse mesh without the commonly adopted corrections as reduced or selective integration or introduction of the stabilization matrices, additional constraints, etc., for the small depth–length ratio. © 1997 John Wiley & Sons, Ltd. 相似文献
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