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排序方式: 共有593条查询结果,搜索用时 31 毫秒
1.
A Confocal Scanning Laser Microscope equipped with a gold image furnace was used to directly observe the precipitation of MnS during solidification of high sulphur steels under isothermal conditions in the temperature region 1440 to 1480°C on the free surface of the steel melt. For the case of Al‐killed steels, below 1480°C MnS particles were found to precipitate with Fe forming simultaneously around them. This MnS containing structure continued to grow rapidly (264 μm/s) as a surface film. The film gradually changed, as the level of S in the melt decreased, into a eutectic structure (with lamella spacing of 2 μm) as predicted by thermodynamics. In Si‐ killed steels there was significantly lower tendency to form MnS both in terms of time until precipitation occurred and growth rate. 相似文献
2.
Juan D. Manrique Mohamed Al-Hussein Avi Telyas Geoff Funston 《Canadian Metallurgical Quarterly》2007,133(3):208-216
This paper focuses on the procedure utilized in the construction of tilt-up irregular concrete panels that are constructed on-site using concrete slabs and wooden formwork. The case study required high-quality concrete finishing. The erection and installation procedure called for a maximum panel-to-panel joint tolerance of 1.27?cm (0.5?in.), often 90° joints between panels. To meet precision requirements, the casting slabs were leveled and flattened with laser screed technology and smoothed with chemical solutions. To ensure that the final result met expectations, a mock-up model was built using different types of materials and to simulate site constraints. The architectural design is a composition of precast concrete panels like “Lego” pieces assembled similarly to a jigsaw puzzle. The unique construction process required a state-of-the-art analysis to produce the set quality. Quality conditions as set by the owner included creating a smooth concrete surface on all panels while avoiding damages and reducing equipment and material costs. The proposed methodology is described through its implementation on the case study, which is also described in this paper. 相似文献
3.
Iron molybdate (Fe2MoO4) powders with an average particle size of 100 μm were reduced by hydrogen using a fluidized-bed batch reactor in the temperature range of 923 to 1173 K. The extent of the
reaction was followed as a function of time by gas chromatography. The fluidizing-gas velocity was set at about 1.5 times
the minimum fluidization velocity. The ratio of the height of the static bed to its diameter is about 1. Under the prevailing
experimental conditions, it was found that the chemical reaction was the rate-controlling factor. The activation energy for
this process was 158±17 kJ/mol. The crystal size of the Fe2Mo powder produced at lower temperatures was in the nanometer range, indicating the possibility of mass production of alloys
and intermetallics in the nanorange, using a fluidized bed. 相似文献
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7.
Abu Avi Lupa Israel 《AEUE-International Journal of Electronics and Communications》2005,59(5):307-310
This letter presents a general analysis of time jitter in sigma-delta synthesizer. One of the practical applications of 1-bit sigma-delta systems is a generation of high-resolution local oscillator (LO) signals. In order to generate LO signals, one may use a single-bit sigma-delta technique to encode sine waves. Today, direct generation of high-frequency sine wave using a clock with higher frequency, is possible. In this letter, we will analyze different LO signal generators and develop a practical way of computation to decide how to choose the best configuration under minimum degradation of signal-to-noise ratio (SNR) at the output. 相似文献
8.
Guna Seetharaman 《Theoretical computer science》1995,140(2):319-331
It is proposed to enhance and simplify the programming of a two dimensional (2-D) torus (and mesh) connected SIMD array of simple processing elements (PEs) by introducing two dedicated communication registers in each PE. A new SIMD algorithm to transpose a matrix using only two buffers at each PE is described. A method is proposed to effectively realize large number of arbitrary, one-to-one, personalized, and concurrent communication between the PEs, by suitably repeating the matrix transpose algorithm. Implementation of several image processing tasks of shift-variant nature, such as hough transform, histogram, median filters, which involve such communication, is enhanced by this approach. The dynamic behavior of such a SIMD implementation is data independent, unlike the ones that employ greedy methods for handling the overall communication. This feature facilitates coordinated use of several independently operating SIMD meshes in a newly emerging computer vision paradigm known as multiview image-sequence analysis (MVISA) for 3-D perception of unstructured dynamic scenes. 相似文献
9.
Summary The major losses in nitrogen and free amino acids (FAA) of the potato during the add-back (A-B) process were in the pre-cooking and mash-mixing steps (Fig. 1). These losses were due to leaching of nitrogen compounds into the processing water and heating.The FAA pool of the potato is composed mainly of the amides (asparagine and glutamine), aspartic and glutamic acids (approx. 53%). These amino acids were degraded substantially during the add-back process. There was also a significant loss in valine, threonine, serine, leucine, phenylalanine, and arginine, but no change in -aminobutyric acid (GABA).
Einfluß des Add-Back Prozesses auf die freie Aminosäuremenge von Kartoffeln
Zusammenfassung Die Hauptverluste an Stickstoff und freien Aminosäuren werden bei der Kartoffel während des Add-back-Prozesses (A-B) beim Vorkochen und bei der Zerkleinerung (Abb. 1) festgestellt. Die Verluste sind durch das Auswaschen der Stickstoffverbindungen mit dem für die Herstellung erforderlichen Wasser und durch die Erhitzung bedingt. Die freien Aminosäuren der Kartoffel setzen sich im wesentlichen aus Amiden (Asparagin und Glutamin), Asparagin- und Glutaminsäuren (ca. 53%) zusammen. Die Amisnosäuren werden hauptsächlich während des Add-Back-Prozesses abgebaut. Ebenso nehmen Valin, Threonin, Serin, Leucin, Phenylalanin und Arginin im Verlauf des Prozesses signifikant ab, jedoch veränderte sich der -Aminobuttersäuregehalt (GABA) nicht.相似文献
10.
Avi Parush Chelsea Kramer Tara Foster-Hunt Alicia McMullan Kathryn Momtahan 《Cognition, Technology & Work》2014,16(1):47-57
Teamwork is prevalent in many work contexts. This study explored the similarities and differences in teamwork processes across different healthcare work contexts with the aim of assessing knowledge transfer feasibility. The research approach was to aggregate team communication analyses from four healthcare contexts to uncover teamwork similarities and differences. The four healthcare contexts included two handoffs and two surgery contexts. The communication analysis segmented communication into meaningful sequences. It categorized utterances into content categories and verbal behaviors. There were a few similar content categories across the four contexts. A clear information structure emerged in the two handoff contexts. In addition, there were more dialogues and requests in the surgeries compared to more reports in the handoffs. The content similarities suggest that some knowledge is transferable among the contexts. However, the differences in communication patterns reflect fundamental differences between handoff and surgery contexts in some teamwork processes. This research demonstrated that using communication analysis can uncover similarities and differences in team cognition and teamwork processes across work contexts. This in turn can help determine what knowledge and methods pertaining to team training, procedures, and technology are transferable across the contexts. 相似文献