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991.
Roman Tankelevich Graeme Fairweather Andreas Karageorghis Yiorgos‐Sokratis Smyrlis 《International journal for numerical methods in engineering》2006,68(12):1257-1280
We propose a new geometric modelling method based on the so‐called potential field (PF) modelling technique. The harmonic problem associated with this technique is solved numerically using the method of fundamental solutions (MFS). We investigate the applicability of the proposed approach to parametrically defined curves of varying complexity. Based on the MFS, we also provide definitions of the Boolean operations associated with the geometric modelling. Finally, we give practical applications of the method to computer‐aided design and manufacturing problems. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
992.
The paper concerns washboarding phenomenon where for every kind of sawing a very regular pattern is characterised by a sinusoidal – like variation in board thickness. That pattern is an effect of the saw blade lateral vibrations. It is palpable that these vibrations are detrimental to the cutting process, and lead to poor surface quality and dimensional accuracy, and raw material waste. For band saws in the contemporary literature models explaining a washboarding phenomenon are supported on self-excited (self-induced) vibration theories. However, these explanations cannot be simply broadened into the washboarding phenomenon in frame sawing machines. In this work based on theoretical and experimental investigation the washboard pattern formation is clarified by the authors with the use of a theoretical model, in which the rugged surface is an effect of vibrations generated by lateral cyclic loading and lagged wave formation. The authors hope that their obtained results contribute significantly to further understanding of this important but complicated phenomenon. 相似文献
993.
994.
While hardware/software partitioning has been shown to provide significant performance gains, most hardware/software partitioning
approaches are limited to partitioning computational kernels utilizing integers or fixed point implementations. Software developers
often initially develop an application using floating point representations built-in to most programming languages and later
convert the application to a fixed point representation—a potentially time consuming process. In this paper, we present the
Arizona Float ⇔ Fixed Hardware Library (AFFHL) consisting of efficient, configurable floating point to fixed point and fixed point to floating
point hardware converters. By utilizing these converters, a system’s hardware/software implementation can be separated into
a floating point domain consisting of the microprocessor and memory subsystem and a fixed point domain consisting of one or
more partitioned hardware coprocessors. This separation enables a rapid hardware/software partitioning approach in which floating
point software kernels can be implemented using fixed point hardware coprocessors without the need for application developers
to first rewrite software applications as fixed point implementations. We further present an overview of a basic hardware/software
partitioning methodology for rapidly partitioning computational kernels within floating point software application to either
statically determined fixed point hardware coprocessors or dynamically adaptable fixed point hardware coprocessors in which
the required fixed point representation can be dynamically determined and adjusted at runtime. 相似文献
995.
Marina Lesnichaya Roman Shendrik Evgeniy Titov Boris Sukhov 《IET nanobiotechnology / IET》2020,14(6):519
In the present study, water‐soluble hybrid selenium‐containing nanocomposites have been synthesised via soft oxidation of selenide‐anions, preliminarily generated from elemental bulk‐selenium in the base‐reduction system ‘N2 H4 –NaOH’. The nanocomposites obtained consist of Se0 NPs (4.6–24.5 nm) stabilised by κ‐carrageenan biocompatible polysaccharide. The structure of these composite nanomaterials has been proven using complementary physical–chemical methods: X‐ray diffraction analysis, transmission electron microscopy, optical spectroscopy, and dynamic light scattering. Optical ranges of ‘emission/excitation’ of aqueous solutions of nanocomposites with Se0 NPs of different sizes are established and the most important parameters of their luminescence are determined. For the obtained nanocomposites, the expressed antiradical activity against free radicals 2,2‐diphenyl‐1‐picrylhydrazyl and 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid has been found, the value of which depends on the size of selenium nanoparticles. It is experimentally revealed that all obtained nanocomposites are low toxic (LD50 >2000 mg/kg). It is also found that small selenium nanoparticles (6.8 nm), in contrast to larger nanoparticles (24.5 nm), are accumulated in organisms to significantly increase the level of selenium in the liver, kidneys, and brain (in lesser amounts) of rats.Inspec keywords: nanobiotechnology, free radical reactions, oxidation, enzymes, selenium, solubility, nanofabrication, transmission electron microscopy, X‐ray diffraction, free radicals, reduction (chemical), biomedical materials, nanoparticles, nanomedicine, light scattering, organic‐inorganic hybrid materials, biochemistry, nanocompositesOther keywords: κ‐carrageenan biocompatible polysaccharide, composite nanomaterials, complementary physical–chemical methods, X‐ray diffraction analysis, transmission electron microscopy, optical spectroscopy, dynamic light scattering, optical ranges, expressed antiradical activity, 2,2‐diphenyl‐1‐picrylhydrazyl, 3‐ethylbenzothiazoline‐6‐sulphonic acid, comparative assessment, toxicity, κ‐carrageenan‐capped selenium nanoparticles, water‐soluble hybrid selenium‐containing nanocomposites, soft oxidation, selenide‐anions, elemental bulk‐selenium, base‐reduction system, free radicals, 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid, selenium nanoparticles, nanocomposites, liver, kidneys, brain, luminescence, size 4.6 nm to 24.5 nm 相似文献
996.
Timothy V. Pyrkov Roman G. Efremov 《International journal of molecular sciences》2007,8(11):1083-1094
ATP is involved in numerous biochemical reactions in living cells interacting with different proteins. Molecular docking simulations provide considerable insight into the problem of molecular recognition of this substrate. To improve the selection of correct ATP poses among those generated by docking algorithms we propose a post-docking reranking criterion. The method is based on detailed analysis of the intermolecular interactions in 50 high-resolution 3D-structures of ATP-protein complexes. A distinctive new feature of the proposed method is that the ligand molecule is divided into fragments that differ in their physical properties. The placement of each of them into the binding site is judged separately by different criteria, thus avoiding undesirable averaging of the scoring function terms by highlighting those relevant for particular fragments. The scoring performance of the new criteria was tested with the docking solutions for ATPprotein complexes and a significant improvement in the selection of correct docking poses was observed, as compared to the standard scoring function. 相似文献
997.
998.
Francesco Di Stasio Joel Q. Grim Vladimir Lesnyak Prachi Rastogi Liberato Manna Iwan Moreels Roman Krahne 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(11):1328-1334
Core–shell CdSe/CdS nanocrystals are a very promising material for light emitting applications. Their solution‐phase synthesis is based on surface‐stabilizing ligands that make them soluble in organic solvents, like toluene or chloroform. However, solubility of these materials in water provides many advantages, such as additional process routes and easier handling. So far, solubilization of CdSe/CdS nanocrystals in water that avoids detrimental effects on the luminescent properties poses a major challenge. This work demonstrates how core–shell CdSe/CdS quantum dot‐in‐rods can be transferred into water using a ligand exchange method employing mercaptopropionic acid (MPA). Key to maintaining the light‐emitting properties is an enlarged CdS rod diameter, which prevents potential surface defects formed during the ligand exchange from affecting the photophysics of the dot‐in‐rods. Films made from water‐soluble dot‐in‐rods show amplified spontaneous emission (ASE) with a similar threshold (130 μJ/cm2) as the pristine material (115 μJ/cm2). To demonstrate feasibility for lasing applications, self‐assembled microlasers are fabricated via the “coffee‐ring effect” that display single‐mode operation and a very low threshold of ~10 μJ/cm2. The performance of these microlasers is enhanced by the small size of MPA ligands, enabling a high packing density of the dot‐in‐rods. 相似文献
999.
Siderophores are naturally occurring small molecules with metal binding constants greater than many synthetic chelators. Herein, we report a two‐step process to graft a siderophore‐mimetic metal chelating polymer from a polypropylene (PP) surface. Poly(methyl acrylate) was first grafted from the PP surface by photoinitiated graft polymerization, followed by the conversion into poly(hydroxamic acid) (PHA) to obtain PP‐g‐PHA films. ATR/FTIR, contact angle, SEM, and AFM were performed to characterize surface properties of films. Iron binding kinetics and the influence of pH (3.0–5.0) on the chelating ability of films were determined. PP‐g‐PHA exhibited significant iron chelating activity (~80 nmol/cm2) with an equilibration time of 24 h. The materials retained 50% chelating ability at pH 3.0 compared with pH 5.0, almost double the retention of previously reported polycarboxylate chelating interfaces. By using siderophore‐mimetic surface chemistry, such effective metal chelating interfaces can extend the applications of metal chelating polymers in environmental remediation, water purification, and active packaging areas. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41231. 相似文献
1000.
Erik P. Schartner Georgios Tsiminis Alexandre François Roman Kostecki Stephen C. Warren-Smith Linh Viet Nguyen Sabrina Heng Tess Reynolds Elizaveta Klantsataya Kris J. Rowland Andrew D. Abell Heike Ebendorff-Heidepriem Tanya M. Monro 《International Journal of Applied Glass Science》2015,6(3):229-239
In this review, we examine recent developments in the field of chemical and biological sensing utilizing suspended-core, exposed-core, and hollow-core microstructured optical fibers. Depending on the intended application, a host of sensing modalities have been utilized including labelled fluorescence techniques, and label-free methods such as surface plasmon resonance, fiber Bragg gratings, and Raman scattering. The use of various functionalization techniques adds specificity to both chemical ions and biological molecules. The results shown here highlight some of the important benefits that arise with the use of microstructured optical fibers compared to traditional techniques, including small sample volumes, high sensitivity, and multiplexing. 相似文献