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121.
The increase in computational capabilities has made time-domain methods applicable for long-range sound propagation modelling. However, such approaches remain very demanding in terms of computational resources. Most current computers are supplied with a powerful device which is still little exploited: the graphics processing unit (GPU). The paper describes an implementation of a transmission line matrix model which allows parallel calculations on heterogeneous systems. A voxelization algorithm used to generate the computational domain is presented. A splitting process is also expounded which makes feasible performing huge domains simulations by accurately dividing the computational domain into subdomains. Each subdomain is enlarged by introducing extra cells containing neighbours subdomains data in order to run several computational iterations on a graphic device without data exchange with the system memory. The influence of the ghost layer depth and the speeding up of computation time with GPU are then illustrated in a realistic built-up area. 相似文献
122.
Antoine Diguet Maël Le Berre Yong Chen Damien Baigl 《Small (Weinheim an der Bergstrasse, Germany)》2009,5(14):1661-1666
By dragging a phospholipid solution on microstructured silicon surfaces, phospholipid molecules are selectively deposited inside the microstructures to get regular phospholipid multilayer patterns of controlled thickness over a large scale (~cm2). By varying the dragging speed, the thickness of the patterns varies between 28 and 100 nm on average (7 to 25 bilayers). Electroswelling of phospholipid multilayer patterns leads to the formation of giant liposomes of controlled size and narrow size distributions. 相似文献
123.
Gaëtan Compère Jean‐François Remacle Johan Jansson Johan Hoffman 《International journal for numerical methods in engineering》2010,82(7):843-867
In this paper, we identify and propose solutions for several issues encountered when designing a mesh adaptation package, such as mesh‐to‐mesh projections and mesh database design, and we describe an algorithm to integrate a mesh adaptation procedure in a physics solver. The open‐source MAdLib package is presented as an example of such a mesh adaptation library. A new technique combining global node repositioning and mesh optimization in order to perform arbitrarily large deformations is also proposed. We then present several test cases to evaluate the performances of the proposed techniques and to show their applicability to fluid–structure interaction problems with arbitrarily large deformations. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
124.
125.
Effect of viscosities of dispersed and continuous phases in microchannel oil-in-water emulsification
Koen van Dijke Isao Kobayashi Karin Schroën Kunihiko Uemura Mitsutoshi Nakajima Remko Boom 《Microfluidics and nanofluidics》2010,9(1):77-85
Although many aspects of microchannel emulsification have been covered in literature, one major uncharted area is the effect
of viscosity of both phases on droplet size in the stable droplet generation regime. It is expected that for droplet formation
to take place, the inflow of the continuous phase should be sufficiently fast compared to the outflow of the liquid that is
forming the droplet. The ratio of the viscosities was therefore varied by using a range of continuous and dispersed phases,
both experimentally and computationally. At high viscosity ratio (η
d/η
c), the droplet size is constant; the inflow of the continuous phase is fast compared to the outflow of the dispersed phase.
At lower ratios, the droplet diameter increases, until a viscosity ratio is reached at which droplet formation is no longer
possible (the minimal ratio). This was confirmed and elucidated through CFD simulations. The limiting value is shown to be
a function of the microchannel design, and this should be adapted to the viscosity of the two fluids that need to be emulsified. 相似文献
126.
Ouardia Zamoume Sophie Thibault Gwenaël Regnié Med Omar Mecherri Marina Fiallo Patrick Sharrock 《Materials science & engineering. C, Materials for biological applications》2011,31(7):1352-1356
Limited blood circulation to the skeletal tissue is a major cause of reduced therapeutic effects seen with drugs administered by conventional systemic ways. To resolve this issue and obtain a sufficiently high local concentration to induce therapeutic effects, several implanted drug delivery systems have been developed for hard tissues using biomaterials.We have designed a drug delivery device based on hydroxylapatite (HA) and tested it in vitro using metronidazol and chloramphenicol as model compounds. Porous HA ceramics were prepared with two different shapes (cylindrical and spherical). Known amounts of drugs were introduced inside a drilled hole and sealed with wax. The ceramics were then suspended in stirred distilled water in closed polypropylene vials. Drug release was observed during several weeks.A mathematical model used to describe drug release from HA was elaborated based on the expressions of Fick's laws. The experimental kinetic results could be related to ceramic constitution and to drug localization. 相似文献
127.
Abdallah Hamze Dr. Anne Giraud Dr. Samir Messaoudi Dr. Olivier Provot Dr. Jean‐François Peyrat Prof. Jérôme Bignon Dr. Jian‐Miao Liu Dr. Joanna Wdzieczak‐Bakala Dr. Sylviane Thoret Joëlle Dubois Dr. Jean‐Daniel Brion Prof. Mouad Alami Dr. 《ChemMedChem》2009,4(11):1912-1924
The cytotoxic activities of 23 new isocombretastatin A derivatives with modifications on the B‐ring were investigated. Several compounds exhibited excellent antiproliferative activity at nanomolar concentrations against a panel of human cancer cell lines. Compounds isoFCA‐4 ( 2 e ), isoCA‐4 ( 2 k ) and isoNH2CA‐4 ( 2 s ) were the most cytotoxic, and strongly inhibited tubulin polymerization with IC50 values of 4, 2 and 1.5 μM , respectively. These derivatives were found to be 10‐fold more active than phenstatin and colchicine with respect to growth inhibition but displayed similar activities as tubulin polymerization inhibitors. In addition, cell cycle arrest in the G2/M phase and subsequent apoptosis was observed in three cancer cell lines when treated with these compounds. The disruptive effect of 2 e , 2 k and 2 s on the vessel‐like structures formed by human umbilical vein endothelial cells (HUVEC) suggest that these compounds may act as vascular disrupting agents. Both compounds 2 k and 2 s have the potential for further prodrug modification and development as vascular disrupting agents for treatment of solid tumors. 相似文献
128.
M. Jemmali S. Walha M. Pasturel O. Tougait R. Ben Hassen H. Noël 《Journal of Alloys and Compounds》2010,489(2):421-423
Physico-chemical analysis techniques, including X-ray diffraction and Scanning Electron Microscope–Energy Dispersive X-ray Spectroscopy, were employed to construct the isothermal section of the Er–Fe–Al system at 800 °C. At this temperature, the phase diagram is characterized by the formation of five intermediate phases, ErFe12?xAlx with 5 ≤ x ≤ 8 (ThMn12-type), ErFe1+xAl1?x with ?0.2 ≤ x ≤ 0.75 (MgZn2-type), ErFe3?xAlx with 0.5 < x ≤ 1 (DyFe2Al-type), Er2Fe17?xAlx with 4.74 ≤ x ≤ 5.7 (TbCu7-type) and Er2Fe17?xAlx with 5.7 < x ≤ 9.5 (Th2Zn17-type), seven extensions of binaries into the ternary system; ErFexAl3?x with x < 0.5 (Au3Cu-type), ErFexAl2?x with x ≤ 0.68 (MgCu2-type), Er2FexAl1?x with x ≤ 0.25 (Co2Si-type), ErFe2?xAlx with x ≤ 0.5 (MgCu2-type), ErFe3?xAlx with x ≤ 0.5 (Be3Nb-type), Er6Fe23?xAlx with x ≤ 8 (Th6Mn23-type), and Er2Fe17?xAlx with x ≤ 4.75 (Th2Ni17-type) and one intermetallic compound; the ErFe2Al10 (YbFe2Al10-type). 相似文献
129.
Fouling in membrane coupled photocatalytic reactors was investigated in the case of greywater treatment by establishing the link between product type, dose, irradiation time and fouling rates in a cross flow membrane cell fitted with a 0.4 μm pore sized polyethylene membrane. Rapid fouling occurred only with shower gels and conditioners and was linked to changes in the organo-TiO2 aggregate size postulated to be caused by polymers within the products. Fouling was reduced to a negligible level when sufficient irradiation was applied demonstrating that the membrane component of the process is not the issue and that scale up and implementation of the process relates to effective design of the UV reactor. 相似文献
130.
Ultrafast compound imaging for 2-D motion vector estimation: application to transient elastography 总被引:1,自引:0,他引:1
Tanter M Bercoff J Sandrin L Fink M 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2002,49(10):1363-1374
This paper describes a new technique for two-dimensional (2-D) imaging of the motion vector at a very high frame rate with ultrasound. Its potential is experimentally demonstrated for transient elastography. But, beyond this application, it also could be promising for color flow and reflectivity imaging. To date, only axial displacements induced in human tissues by low-frequency vibrators were measured during transient elastography. The proposed technique allows us to follow both axial and lateral displacements during the shear wave propagation and thus should improve Young's modulus image reconstruction. The process is a combination of several ideas well-known in ultrasonic imaging: ultra-fast imaging, multisynthetic aperture beamforming, 1-D speckle tracking, and compound imaging. Classical beamforming in the transmit mode is replaced here by a single plane wave insonification increasing the frame rate by at least a factor of 128. The beamforming is achieved only in the receive mode on two independent subapertures. Comparison of successive frames by a classical 1-D speckle tracking algorithm allows estimation of displacements along two different directions linked to the subapertures beams. The variance of the estimates is finally improved by tilting the emitting plane wave at each insonification, thus allowing reception of successive decorrelated speckle patterns. 相似文献