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91.
PVC profile extrusion compounds have a unique morphology. While other polymers gradually decrease in extrusion die swell with increasing length/thickness (L/D) ratio, PVC profile extrusion compounds have a low die swell, quite independent of the die's L/D ratio in the range of 5 to 20. The fact that the die land length can be changed without changing the extrudate swell is an important consideration, which makes die design and balancing dies simpler and easier for PVC profile extrusion compounds. While other polymers substantially increase extrudate swell with increased shear rate, the swell of the PVC profile compounds is not much affected by shear or extrusion rate. This unique behavior allows wider processing latitude in profile extrusion and faster extrusion rates than with other polymers. Another unique factor in the rheology of PVC profile extrusion compounds is that extrusion die swell increases with increasing melt temperature, while other polymers have decreasing die swell with increasing melt temperature. The unusual rheology of PVC profile extrusion compounds is attributed to its unique melt morphology, where the melt flow units are 1 um bundles and molecules that have low surface to surface interaction and entanglement at low processing temperatures but increased melting and increased entanglement at higher processing temperatures. Other polymers, unlike PVC, have melt flow at the molecular level. 相似文献
92.
The purpose of this work was to examine the possible significance in the formation of metallurgical coke of the anisotropic spherical mesophase exemplified by that found during the carbonization of pitch-like materials, and to ascertain if the various types of optical anisotropy found in coke could form a basis for the characterization of cokes produced from different coals. Vitrains from a wide range of coals were carbonized at temperatures from 370 to 1000 °C and the types and amounts of optical anisotropy in the resulting semi-cokes and cokes were determined from microscopic examination, the anisotropic components being classified according to grain size of the granular mosaics and appearance. The anisotropy developed directly from the isotropic phase, appearing initially as a fine-grained mosaic. With increasing carbonization temperature, this fine-grained mosaic was transformed into progressively coarser-grained anisotropy, the extent of this transformation depending on the rank of the vitrain. It is therefore concluded that the formation, growth and coalescence of anisotropic spherical bodies, such as occurs during the carbonization of pitch, is not a necessary precursor of the mosaic anisotropy in coke. The type and amount of anisotropy developed provide a quantitative means of characterising different cokes. 相似文献
93.
Charge transfer on boron doped diamond (BDD) electrodes was studied by cyclic voltammetry and electrochemical impedance spectroscopy.
The diamond films of 5 μm thickness and boron content between 200 ppm and 3000 ppm were prepared by the hot filament CVD technique
on niobium substrate and mounted in a Teflon holder as rotating disk electrodes. The electrochemical measurements were carried
out in aqueous electrolyte solutions of 0.5 M Na2
SO
4 + 5 mM K3[Fe(CN)6]/K4[Fe(CN)6]. Significant deviation in the redox behaviour of BDD and active Pt electrodes was indicated by a shift of the peak potentials
in the cyclic voltammograms with increasing sweep rate and lower limiting diffusion current densities under rotating disk
conditions. In the impedance spectra an additional capacitive element appeared at high frequencies. The potential and rotation
dependence of the impedance spectra can be described quantitatively in terms of a model based on diffusion controlled charge
transfer on partially blocked electrode surfaces. Direct evidence for the non-homogeneous current distribution on the diamond
surface was obtained by SECM measurements. 相似文献
94.
95.
Garrett BC Dixon DA Camaioni DM Chipman DM Johnson MA Jonah CD Kimmel GA Miller JH Rescigno TN Rossky PJ Xantheas SS Colson SD Laufer AH Ray D Barbara PF Bartels DM Becker KH Bowen KH Bradforth SE Carmichael I Coe JV Corrales LR Cowin JP Dupuis M Eisenthal KB Franz JA Gutowski MS Jordan KD Kay BD Laverne JA Lymar SV Madey TE McCurdy CW Meisel D Mukamel S Nilsson AR Orlando TM Petrik NG Pimblott SM Rustad JR Schenter GK Singer SJ Tokmakoff A Wang LS Wettig C Zwier TS 《Chemical reviews》2005,105(1):355-390
96.
PU YiFei SIARRY Patrick ZHOU JiLiu LIU YiGuang ZHANG Ni HUANG Guo LIU YiZhi 《中国科学:信息科学(英文版)》2014,(7):180-198
In this paper,a set of fractional partial differential equations based on fractional total variation and fractional steepest descent approach are proposed to address the problem of traditional drawbacks of PM and ROF multi-scale denoising for texture image.By extending Green,Gauss,Stokes and Euler-Lagrange formulas to fractional field,we can find that the integer formulas are just their special case of fractional ones.In order to improve the denoising capability,we proposed 4 fractional partial differential equation based multiscale denoising models,and then discussed their stabilities and convergence rate.Theoretic deduction and experimental evaluation demonstrate the stability and astringency of fractional steepest descent approach,and fractional nonlinearly multi-scale denoising capability and best value of parameters are discussed also.The experiments results prove that the ability for preserving high-frequency edge and complex texture information of the proposed denoising models are obviously superior to traditional integral based algorithms,especially for texture detail rich images. 相似文献
97.
Zhang Yingqian Lombardi Michele De Causmaecker Patrick 《Annals of Mathematics and Artificial Intelligence》2021,89(7):615-616
Annals of Mathematics and Artificial Intelligence - 相似文献
98.
Vladimir Brailovski Patrick Terriault Sergei Prokoshkin 《Journal of Materials Engineering and Performance》2002,11(6):614-621
Shape memory alloys (SMA) suffer from the same impairing mechanisms experienced during cycling loading by classic alloys.
Moreover, SMA fatigue behavior is greatly influenced by thermomechanical cycling through the zone of thermoelastic phase transformation,
which is the basis of shape memory and superelasticity effects. Since the fatigue resistance of any material can be improved
by an appropriate thermomechanical treatment, in the present work combined differential scanning calorimetry and microhardness
testing were used to determine an optimum annealing temperature for the cold-worked Ni-50.1%Ti alloy. The optimization is
based on the assumption that latent heat of transformation is proportional to the mechanical work generated by SMA upon heating,
while material hardness is related to the yield stress of the material. It is supposed that an optimum trade-off in these
two properties guarantees the best dimensional and functional stability of SMA devices. The level and stability of the mechanical
work generated by the material during low-cycle fatigue testing are considered criteria for the material performance and thus
of the validity of the proposed optimization procedure. 相似文献
99.
Jörg Becker Patrick Delfmann Hanns-Alexander Dietrich Matthias Steinhorst Mathias Eggert 《Information Systems Frontiers》2016,18(2):359-405
Given the strong increase in regulatory requirements for business processes the management of business process compliance becomes a more and more regarded field in IS research. Several methods have been developed to support compliance checking of conceptual models. However, their focus on distinct modeling languages and mostly linear (i.e., predecessor-successor related) compliance rules may hinder widespread adoption and application in practice. Furthermore, hardly any of them has been evaluated in a real-world setting. We address this issue by applying a generic pattern matching approach for conceptual models to business process compliance checking in the financial sector. It consists of a model query language, a search algorithm and a corresponding modelling tool prototype. It is (1) applicable for all graph-based conceptual modeling languages and (2) for different kinds of compliance rules. Furthermore, based on an applicability check, we (3) evaluate the approach in a financial industry project setting against its relevance for decision support of audit and compliance management tasks. 相似文献
100.
Eric?ZimmerlingEmail author Patrick?J.?H?flinger Philipp G.?Sandner Isabell M.?Welpe 《Information Systems Frontiers》2016,18(6):1063-1084
This study develops a system framework and an enterprise IT solution for integrating gamification elements to efficiently implement and continuously perform Cost Engineering. Cost Engineering is a systematic approach to manage knowledge and competencies regarding costs reduction measures throughout the life cycle of products and is technology, resource and time intensive. Gamification as a non-monetary multidimensional incentive system holds great potential to implement and establish Cost Engineering in a novel and less resource demanding manner and stipulate knowledge sharing and dissemination. Building on a review of the relevant literature we conducted 20 interviews with experts from eight companies of the German and Austrian high-tech manufacturing industry to examine the system requirements from an organizational perspective. Analyzing the interviews, we found that companies need a flexible platform where the game elements help to align management objectives with concrete tasks, meet legislative regulations and have different evaluation methods. Our proposed system framework combines the organizational and IT requirements with gamification elements to efficiently steer Cost Engineering methods and best manage knowledge and competencies. 相似文献