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41.
This paper presents a comparative study on the Ti2AlC coatings produced by different thermal spray methods, as Ti2AlC is one of the most studied materials from the MAX-phase family. Microstructural analysis of coatings produced by High Velocity Air Fuel (HVAF), Cold Spray and High Velocity Oxygen Fuel (HVOF) has been carried out by means of the scanning electron microscopy equipped with an energy dispersive spectrometer (EDS). The volume fraction of porosity was determined using the ASTM standard E562. The phase characterization of the as-received powder and as-sprayed coatings was conducted using the X-ray diffraction with CrKα radiation. Impact of the spray parameters on the porosity and the mechanical properties of the coatings are discussed. The results show that the spraying temperature and velocity play a crucial role in coatings characteristics. 相似文献
42.
Shreesha Rao D.S Mikkel Jensen Lars Grüner-Nielsen Jesper Toft Olsen Peter Heiduschka Bj?rn Kemper Jürgen Schnekenburger Martin Glud Mette Mogensen Niels M?ller Israelsen Ole Bang 《光:科学与应用(英文版)》2021,10(7):1372-1384
We present the first demonstration of shot-noise limited supercontinuum-based spectral domain optical coherence tomography (SD-OCT) with an axial resolution of ... 相似文献
43.
Bj?rn Petter Jelle 《Journal of Materials Science》2012,47(18):6475-6496
Building materials, components and structures have to fulfil many functional demands during the lifetime of a building. Therefore,
it is important to require satisfactory durability of these materials, components and structures. In fact, one single material
failure may jeopardize whole components as well as structures. Unfortunately, experience shows that building products too
often do not satisfy the various requirements after a relatively short period of use, i.e. the expected service life is considerably
shorter than foreseen. This results in increased and large costs due to increased maintenance, extensive replacements of the
specific building products and any possible consequential building damages. In addition, health hazards with respect to both
risk and consequence may also become an issue. To avoid this, the solution is to apply building products which have properly
documented adequate and satisfactory long-term durability. That is, building products which have been subjected to long-term
natural outdoor climate exposure or appropriate accelerated climate ageing in the laboratory. This study examines the main
climate exposures and how these may be reproduced in the laboratory in various ways. Thus, crucial properties of building
products and their durability towards climate strains may be investigated within a relatively short time frame compared with
natural outdoor climate ageing. Examples of miscellaneous climate ageing laboratory apparatuses, ageing methods and building
product properties to be tested before, during and after ageing are given. A calculation method for estimating acceleration
factors is also discussed. Various ageing examples are shown and discussed. A special note is made towards accelerated climate
ageing of new and advanced materials being developed. Hence, this study addresses durability and the versatile and powerful
application of accelerated climate ageing which is an all too overlooked field within materials science and engineering. 相似文献
44.
Andreas Hugerth Magnus Brisander Ulla Wrange Mikael Kritikos Björn Norrlind Marianne Svensson 《Drug development and industrial pharmacy》2013,39(2):185-196
ABSTRACTThe physicochemical properties of 1-benzenesulfonyl-4-(piperazin-1-yl)-indole hydrochloride, a novel 5-HT6 receptor antagonist for the treatment of obesity were characterized. Two solid state forms were identified at ambient conditions (23°C): an anhydrate form (1) and a hydrate form (2), with 1.5 moles of H2O. The latter easily dehydrates and rehydrates without affecting the crystal morphology. Investigations of the propensity for interconversion between the two forms reveal that a) conversion of 2→1 takes place above 145°C and that b) conversion of 1→2 only occurs after crystallization from supersaturated aqueous solutions at a water activity ≥0.94 or in the presence of comparable amounts of crystals of 2 in water at ambient conditions. However, in an equimolar suspension of 1 and 2 at 37°C no phase transformation was observed. Thus, the difference in chemical potential between the two forms is small. Form 1 was shown to have overall favorable solid state properties and, hence, considered the preferred form for continued pharmaceutical development. The characterization was performed by means of light microscopy, scanning electron microscopy, powder X-ray diffraction, FTIR/NIR-spectroscopy, differential scanning calorimetry, hot stage microscopy, thermogravimetry, dynamic vapor sorption, Karl Fischer water content determination, phase stability studies of suspensions, solubility, and intrinsic dissolution rate measurements. 相似文献
45.
Åsa Laurell Lyne Viveca Wallqvist Mark W. Rutland Per Claesson Björn Birgisson 《Journal of Materials Science》2013,48(20):6970-6976
The so called “bee phenomenon” in bitumen has been investigated by means of AFM quantitative nanomechanical property mapping. Bees are a phenomenon that can be observed by topography measurements using AFM. The characteristic “bee” appearance comes from regions with alternating higher and lower bands in the surface topography of bitumen, which are surrounded by a flat area. The proposed mechanism for bee formation is phase separation and differential contraction during cooling from melt temperatures leading to wrinkling due to differences in the elastic modulus of the material phases. Using a laminate wrinkling model, the thickness of the bee laminate was calculated from the wavelengths and Young’s moduli of the bee laminate and the matrix. It was found to vary between 70 and 140 nm for the five bitumen samples that contained significant amounts of wax. 相似文献
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48.
Parastoo Mohagheghi Wasif Gilani Alin Stefanescu Miguel A. Fernandez Bjørn Nordmoen Mathias Fritzsche 《Software and Systems Modeling》2013,12(3):619-639
There have been few experience reports from industry on how Model-Driven Engineering (MDE) is applied and what the benefits are. This paper summarizes the experiences of three large industrial participants in a European research project with the objective of developing techniques and tools for applying MDE on the development of large and complex software systems. The participants had varying degrees of previous experience with MDE. They found MDE to be particularly useful for providing abstractions of complex systems at multiple levels or from different viewpoints, for the development of domain-specific models that facilitate communication with non-technical experts, for the purposes of simulation and testing, and for the consumption of models for analysis, such as performance-related decision support and system design improvements. From the industrial perspective, a methodology is considered to be useful and cost-efficient if it is possible to reuse solutions in multiple projects or products. However, developing reusable solutions required extra effort and sometimes had a negative impact on the performance of tools. While the companies identified several benefits of MDE, merging different tools with one another in a seamless development environment required several transformations, which increased the required implementation effort and complexity. Additionally, user-friendliness of tools and the provision of features for managing models of complex systems were identified as crucial for a wider industrial adoption of MDE. 相似文献
49.
Robert Anderson Björn Stenger Roberto Cipolla 《International Journal of Computer Vision》2014,110(1):48-57
We present a method for producing dense active appearance models (AAMs), suitable for video-realistic synthesis. To this end we estimate a joint alignment of all training images using a set of pairwise registrations and ensure that these pairwise registrations are only calculated between similar images. This is achieved by defining a graph on the image set whose edge weights correspond to registration errors and computing a bounded diameter minimum spanning tree. Dense optical flow is used to compute pairwise registration and a flow refinement method to align small scale texture is introduced. Further, given the registration of training images, vertices are added to the AAM to minimise the error between the observed flow fields and the flow fields interpolated between the AAM mesh points. We demonstrate a significant improvement in model compactness. 相似文献
50.
C. J. E. Metcalf G. H. Long N. Mideo J. D. Forester O. N. Bj?rnstad A. L. Graham 《Journal of the Royal Society Interface》2012,9(76):2804-2813
Malaria parasite clones with the highest transmission rates to mosquitoes also tend to induce the most severe fitness consequences (or virulence) in mammals. This is in accord with expectations from the virulence–transmission trade-off hypothesis. However, the mechanisms underlying how different clones cause virulence are not well understood. Here, using data from eight murine malaria clones, we apply recently developed statistical methods to infer differences in clone characteristics, including induction of differing host-mediated changes in red blood cell (RBC) supply. Our results indicate that the within-host mechanisms underlying similar levels of virulence are variable and that killing of uninfected RBCs by immune effectors and/or retention of RBCs in the spleen may ultimately reduce virulence. Furthermore, the correlation between clone virulence and the degree of host-induced mortality of uninfected RBCs indicates that hosts increasingly restrict their RBC supply with increasing intrinsic virulence of the clone with which they are infected. Our results demonstrate a role for self-harm in self-defence for hosts and highlight the diversity and modes of virulence of malaria. 相似文献