排序方式: 共有18条查询结果,搜索用时 15 毫秒
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Jeffrey J. Lombardo Roger A. Ristau William M. Harris Wilson K. S. Chiu 《Journal of synchrotron radiation》2012,19(5):789-796
The preparation of hard material samples with the necessary size and shape is critical to successful material analysis. X‐ray nanotomography requires that samples are sufficiently thin for X‐rays to pass through the sample during rotation for tomography. One method for producing samples that fit the criteria for X‐ray nanotomography is focused ion beam/scanning electron microscopy (FIB/SEM) which uses a focused beam of ions to selectively mill around a region of interest and then utilizes a micromanipulator to remove the milled‐out sample from the bulk material and mount it on a sample holder. In this article the process for preparing X‐ray nanotomography samples in multiple shapes and sizes is discussed. Additionally, solid‐oxide fuel cell anode samples prepared through the FIB/SEM technique underwent volume‐independence studies for multiple properties such as volume fraction, average particle size, tortuosity and contiguity to observe the characteristics of FIB/SEM samples in X‐ray nanotomography. 相似文献
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During the last decade, striking improvements could be achieved for the precise control of deposition processes in optical coating technology. For example, as a consequence of enormous progresses in measure- ment and computer technology, direct optical monitoring in a broad spectral range can be considered as a common tool in many production environments nowadays. Besides the development of the corresponding hardware and measurement channels, advanced approaches for the evaluation of the acquired data and new multiple sensor monitoring strategies moved into the focus of modern research on the way towards de- terministic deposition techniques. In this context, also innovative concepts for the simulation of deposition processes to forecast the result for a specified coating design and automatic online correction algorithms gained of importance to reduce the risk of failure in coating production. The present contribution will be dedicated to selected aspects in this field, especially addressing broad band optical monitoring systems. A short review on examples for existing hardware configurations and software tools will be presented illus- trating the advantages of modern process control techniques. Novel approaches based on the modeling of thin film growth are discussed as an additional strategy to improve the predictability of coating processes. 相似文献
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King'ondu CK Iyer A Njagi EC Opembe N Genuino H Huang H Ristau RA Suib SL 《Journal of the American Chemical Society》2011,133(12):4186-4189
Short reaction times and morphology control in the synthesis of inorganic materials under nonthermal conditions remain a challenge. Herein we report a rapid, self-templating, and nonthermal method based on ultraviolet light to prepare metal oxide hierarchical structures. With this method, the morphology of the metal oxides was controlled readily without using templates. 相似文献
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Elemental sulphur, a common constituent of marine sediments, has been shown to give dialkyl sulphides with the Grignard reagents commonly used to derivatize alkyltin species before their determination by gas chromatography with flame photometric detection (GC–FPD). Further, it has been demonstrated that even with the red filter for 610 nm (normally used for organotin compounds) fitted to the detector, sulphur compounds do give rise to an emission signal, which may be mistaken for tin emission from a pentylated or propylated alkyltin compound, as the respective retention times are in some cases quite close. © 1997 by John Wiley & Sons, Ltd. 相似文献
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Bhm Janko Decker Wolfram Frhbis-Krger Anne Pfreundt Franz-Josef Rahn Mirko Ristau Lukas 《Foundations of Computational Mathematics》2021,21(3):767-806
Foundations of Computational Mathematics - Introducing parallelism and exploring its use is still a fundamental challenge for the computer algebra community. In high-performance numerical... 相似文献
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G. Ankerhold F. Mitschke D. Frerking D. Ristau J. Mlynek W. Lange 《Applied physics. B, Lasers and optics》1989,48(2):101-104
We have fabricated optically bistable interference filters from layers of TiO2 and SiO2 vapour deposited on glass substrates. An experimental comparison with the more conventional ZnSe filters is presented. Our devices are superior in durability and switching contrast, equal in switching threshold, and slower in switching time. 相似文献
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P. Zimmermann D. Ristau E. Welsch 《Applied Physics A: Materials Science & Processing》1994,58(4):377-383
The influence of sample properties on the measured signal has to be investigated, so that measurements of the optical absorption in thin-film coatings by means of the photothermal surface-displacement technique may be precisely performed. Carrying out simultaneously absorption measurements on metal coatings at =10.6 m by using laser calorimetry as well as the surface-displacement technique, the aforementioned influence and the validity of assumptions of the theoretical model, respectively, can be proven. It can be demonstrated that, in contrast to the model, thermophysical coating properties contribute to the probed surface displacement. 相似文献
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An INDO-CI method in π-approximation extended for transition metal complexes with organic ligands is presented. The σ-polarization in the complex is estimated using a two-dimensional EHT calculation and considered in the π-calculation by means of the diagonal Fock matrix elements. The method is tested for four trisdiimine iron(II) complexes. In agreement with the experimental absorption spectra the calculations show that diimine complexes with non-heterocyclicly bound nitrogen atoms exhibit a large red-shift of the characteristic charge-transfer transition increasing the number of aromatic rings. Contrarily, for diimine complexes with heterocyclicly bound nitrogen atoms no shift of the charge-transfer transition was obtained. 相似文献