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891.
水中悬浮法表征碳酸钙的活化效果 总被引:2,自引:0,他引:2
研究了水中悬浮法对碳酸钙活化效果的表征。结果表明,该方法适于表征活性轻质碳酸钙和颗粒极细的活性重质碳酸钙。 相似文献
892.
893.
894.
Marie-Laurence Tremblay Lingling Xu Muzaddid Sarker Xiang-Qin Liu Jan K. Rainey 《International journal of molecular sciences》2016,17(8)
Spider aciniform (wrapping) silk is a remarkable fibrillar biomaterial with outstanding mechanical properties. It is a modular protein consisting, in Argiope trifasciata, of a core repetitive domain of 200 amino acid units (W units). In solution, the W units comprise a globular folded core, with five α-helices, and disordered tails that are linked to form a ~63-residue intrinsically disordered linker in concatemers. Herein, we present nuclear magnetic resonance (NMR) spectroscopy-based 15N spin relaxation analysis, allowing characterization of backbone dynamics as a function of residue on the ps–ns timescale in the context of the single W unit (W1) and the two unit concatemer (W2). Unambiguous mapping of backbone dynamics throughout W2 was made possible by segmental NMR active isotope-enrichment through split intein-mediated trans-splicing. Spectral density mapping for W1 and W2 reveals a striking disparity in dynamics between the folded core and the disordered linker and tail regions. These data are also consistent with rotational diffusion behaviour where each globular domain tumbles almost independently of its neighbour. At a localized level, helix 5 exhibits elevated high frequency dynamics relative to the proximal helix 4, supporting a model of fibrillogenesis where this helix unfolds as part of the transition to a mixed α-helix/β-sheet fibre. 相似文献
895.
AbstractVersatile high-throughput characterization tools are required for the development of new materials using combinatorial techniques. Here, we describe a modular, high-throughput test stand for the screening of thin-film materials libraries, which can carry out automated electrical, magnetic and magnetoresistance measurements in the temperature range of ?40 to 300 °C. As a proof of concept, we measured the temperature-dependent resistance of Fe–Pd–Mn ferromagnetic shape-memory alloy materials libraries, revealing reversible martensitic transformations and the associated transformation temperatures. Magneto-optical screening measurements of a materials library identify ferromagnetic samples, whereas resistivity maps support the discovery of new phases. A distance sensor in the same setup allows stress measurements in materials libraries deposited on cantilever arrays. A combination of these methods offers a fast and reliable high-throughput characterization technology for searching for new materials. Using this approach, a composition region has been identified in the Fe–Pd–Mn system that combines ferromagnetism and martensitic transformation. 相似文献
896.
《Journal of Adhesion Science and Technology》2013,27(10-11):1685-1698
Abstract In this work sodium bisulfate was used as a blocking agent to block polymethylene polyphenylisocyanate (PAPI). The particle size distribution rate and the factors influencing the stability of the blocked isocyanate emulsion were studied by varying the stirring speed. Furthermore the blocked isocyanate was characterized using a variety of methods. In order to determine the best stirring speed for preparing blocked isocyanate, a laser particle size analyzer and thermo gravimetric analysis were used to the measure particle size distribution rate and the stability of the blocked isocyanate emulsion, respectively. Experimental results show that blocked rate was 96.77%, and that the blocked isocyanate emulsion dispersion was best, and had the greatest stability, at the stirring speed of 400 r/min. Different solvents were used to wash the blocked isocyanate emulsion and the freeze-dried product. Analysis by XPS, FTIR, DSC and TGA were used to characterize the blocked products, and the blocked isocyanate was also quantitative analyzed. Results from XPS, FTIR, DSC and TGA analytical methods were able to qualitatively analyze the various components of products. Combining these results with the quantitative analysis the blocked rate of instrument analysis was found to be 86.18%. This was lower than the value of 96.77% for the blocked rate measured by chemical analysis. This work could provide a reference for researchers to distinguish the components of blocked isocyanates and provide an instrument analysis method for measuring the blocked rate. 相似文献
897.
898.
Enrico Vezzetti 《Computer aided design》2011,(8):1074-1088
When talking about reverse engineering, it is necessary to focus on the management of point clouds. Generally speaking, every 3D scanner device codifies simple and complex geometries providing different point cloud densities as an output. Point cloud density is usually more correlated with the technical specifications of the device employed rather than with the morphology of the object acquired. This situation is due to the frequent use of structured grids by a large quantity of devices. In order to solve this problem, we therefore need to integrate the classical structured grid acquisition with a smart selective one, which is able to identify different point cloud densities in accordance with the morphological complexity of the object regions acquired.Currently, we can reach the destination in many different ways. Each of them is able to provide different performances depending on the object morphology and the performances of 3D scanner devices. Unfortunately, there does not yet exist one universal approach able to be employed in all cases. For this reason, the present paper aims to propose a first analysis of the available methodologies and parameters, in order to provide final users with some guidelines for supporting their decisions according to the specific application they are facing. Moreover, the developed guidelines have been illustrated and validated by a series of case studies of the proposed method. 相似文献
899.
B.K. Sharma O.S. Tyagi M.K.S. Aloopwan S.D. Bhagat 《Petroleum Science and Technology》2013,31(3-4):249-272
ABSTRACT NMR and FTIR spectroscopic techniques were used to investigate the effect of different solvent extraction schemes on the composition and chemical nature of species of vacuum residues of two Indian crude oils (namely Jodhpur and Heera) extractable into polar (ethyl acetate) and non-polar (n-pentane and n-heptane) solvents. The obtained soluble fractions were found to consist of mainly simple aliphatic and naphthenic ring structures, while insoluble fractions consisted primarily aromatic compounds. The results were used to draw inferences on the relative utility of different extraction schemes to upgrade vacuum residues as feedstocks for secondary conversion processes in petroleum industry. 相似文献
900.
J. E. deVries 《Journal of Materials Engineering and Performance》1998,7(3):303-311
X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and scanning auger microscopy
(SAM) analytical techniques have played important roles in the characterization of the surface and the interfacial chemistry
governing properties and performance of materials, and material interfaces. These techniques afford spatially resolved elemental
and molecular analysis of the topmost atomic layers of solid surfaces and interfaces. Currently available instrumentation
provides qualitative/quantitative analysis on molecularly complex materials with detection limits in the parts-per-billion
(ppb) range and spatial resolutions approaching 30 nm. Each technique is unique in the information attained, therefore necessitating
a multitechnique approach to achieve a complete surface characterization. Examples of coating/interfacial characterization
by XPS, TOF-SIMS, and SAM are presented illustrating the functionality of these tools and the complimentary natures of them. 相似文献