排序方式: 共有14条查询结果,搜索用时 9 毫秒
1.
Eyal A 《Optics letters》2003,28(10):822-824
It is shown that the mean instantaneous intensity (MII) of a pulse propagating in an optical fiber affected by polarization mode dispersion is related to the frequency autocorrelation of the fiber's Jones matrix through a Fourier transform. A simple derivation of the diffusion equation satisfied by the MII and the autocorrelation function of a Jones matrix is described. 相似文献
2.
Avishay Vaknin 《K-Theory》2001,24(1):57-68
For a small triangulated category
, Bass's K
1 group
is described, and the theorem of the heart is proved. We define the determinant map from
to Neeman's
, and we compute this map when
is the derived category of an Abelian category
. 相似文献
3.
In this Letter we describe a novel method for tunable viscoelastic focusing of particles flowing in a microchannel. It is proposed that some elasticity, inherently present in dilute polymer solutions, may be responsible for highly nonuniform spatial distribution of flowing particles across the channel cross section, yielding their "focusing" in the midplane of the channel. A theory based on scaling arguments is presented to explain the lateral migration and is found to be in a very good agreement with the experimental observations. It was found that, in agreement with the theoretical prediction, the particles would have different spatial distribution depending on their size and rheology of the suspending medium. We demonstrate how the viscoelastic focusing can be precisely controlled by proper rheological design of the carrier solution. 相似文献
4.
To shed light on the role of cell rheology and mechanotransduction in various physiological and disease states, different techniques of force application, such as optical tweezers and deformable substrates, are employed. In this present paper we describe a new approach for the deformation of cells based on the temperature-sensitive polymer poly(N-isopropylacrylamide), PNIPAM. In response to temperature changes, PNIPAM gels undergo extensive and reversible changes in volume that allow them to be used as actuators for stretching and compressing cells and tissues. Herein we focus mainly on our experience with the deformation of red blood cells as proof of principle, and demonstrate the wealth of possibilities such stimuli-responsive materials may offer as actuators. 相似文献
5.
Avishay Aiche Anna Rubinchik Benyamin Shitovitz 《International Journal of Game Theory》2015,44(1):135-151
We examine the asymptotic nucleolus of a smooth and symmetric oligopoly with an atomless sector in a transferable utility (TU) market game. We provide sufficient conditions for the asymptotic core and the nucleolus to coincide with the unique TU competitive payoff distribution. This equivalence results from nucleolus of a finite TU market game belonging to its core, the core equivalence in a symmetric oligopoly with identical atoms and single-valuedness of the core in the limiting smooth game. In some cases (but not always), the asymptotic Shapley value is more favourable for the large traders than the nucleolus, in contrast to the monopoly case (Einy et al. in J Econ Theory 89(2):186–206, 1999), where the nucleolus allocation is larger than the Shapley value for the atom. 相似文献
6.
Pelah A Ludueña SJ Jares-Erijman EA Szleifer I Pietrasanta LI Jovin TM 《Langmuir : the ACS journal of surfaces and colloids》2006,22(23):9682-9686
Stimuli-responsive polymers are used in a large variety of applications due to the controlled manner in which their physical properties can be reversibly altered. In this study, we demonstrate the thermoreversible structuring of poly(N-isopropylacrylamide)-based polymer. By temperature-controlled atomic force microscopy, we demonstrate that polymer aggregates form on mica above the polymer lower critical solution temperature and disperse below it, and in so doing, display positional "memory" in that the nanodomains are retained in the same positions and with the same shapes during repeated cooling/heating cycles. Such positional "memory" may be useful for multiple applications in nano-microscale devices. 相似文献
7.
Coalescence-assisted generation of single nanoliter droplets with predefined composition 总被引:1,自引:0,他引:1
We demonstrate the generation of highly accurate nanoliter droplets with a predefined composition. This composition control over a single droplet is achieved by merging two droplets with known concentrations and defined volumes. A forced coalescence is accomplished by synchronizing two piezoelectric-based active droplet generators. A microscope-mounted CCD camera is used to record, quantify and monitor the process to assure its high fidelity. The device is disposable, surfactant free, simple to operate and does not require microelectrode fabrication. It delivers a single on-demand droplet with adjustable high resolution mixing ratios up to 9 at a volume range of 1-10 nanoliters. The presented platform offers, for the first time, a means to perform droplet-based high-throughput screening in the nanoliter range. 相似文献
8.
9.
The culture of cells in a microbioreactor can be highly beneficial for cell biology studies and tissue engineering applications. The present work provides new insights into the relationship between cell growth, cell morphology, perfusion rate, and design parameters in microchannel bioreactors. We demonstrate the long-term culture of mammalian (human foreskin fibroblasts, HFF) cells in a microbioreactor under constant perfusion in a straightforward simple manner. A perfusion system was used to culture human cells for more than two weeks in a plain microchannel (130 microm x 1 mm x 2 cm). At static conditions and at high flow rates (>0.3 ml h(-1)), the cells did not grow in the microchannel for more than a few days. For low flow rates (<0.2 ml h(-1)), the cells grew well and a confluent layer was obtained. We show that the culture of cells in microchannels under perfusion, even at low rates, affects cell growth kinetics as well as cell morphology. The oxygen level in the microchannel was evaluated using a mass transport model and the maximum cell density measured in the microchannel at steady state. The maximum shear stress, which corresponds to the maximum flow rate used for long term culture, was 20 mPa, which is significantly lower than the shear stress cells may endure under physiological conditions. The effect of channel size and cell type on long term cell culture were also examined and were found to be significant. The presented results demonstrate the importance of understanding the relationship between design parameters and cell behavior in microscale culture system, which vary from physiological and traditional culture conditions. 相似文献
10.
Bransky Avishay Korin Natanel Leshansky Alexander Lanir Naomi Nemirovski Yael Dinnar Uri 《Rheologica Acta》2007,46(5):621-627
Red blood cells (RBCs) suspended in a high-viscosity medium were filmed while flowing through a microchannel using an automated
rheoscope. Under these conditions, erythrocytes take different orientations and undergo varying deformation according to their
location in the velocity profile. Measurements of the mean deformation at several distances from the center of the microchannel
at a constant flow rate were acquired for normal and thalassemia erythrocytes. The measurements demonstrate how diagnosis
can be made based on a single flow rate in contrast to conventional methods where shear is mechanically controlled. The spatial
distribution and velocity of RBCs and rigid microspheres (1 μm) were measured. The maximum slip velocity was found to be linearly
correlated to the flow rate for both cells and microspheres. RBCs showed enhanced inward lateral migration compared to the
rigid spheres, which is attributed to RBC deformation. The results demonstrate the coupling between RBC mechanical properties
and their motion in microvessels.
This paper was presented at Annual European Rheology Conference (AERC) held in Hersonisos, Crete, Greece, April 27-29, 2006. 相似文献