James C. W. Chen

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Noninvasive, easy-to-use and accurate measurements of wall shear stress (WSS) in human blood vessels have always been challenging in clinical applications. Echo particle image velocimetry (Echo PIV) has shown promise for clinical measurements of local hemodynamics and wall shear rate. Thus far, however, the method has only been validated under simple flow(More)
At the concentration of 3–6 μg/ml, Cytochalasin B completely inhibits the protoplasmic streaming in theNitella rhizoid within 10 to 25 minutes. Under the influence of the chemical, behavior of the endoplasm leading to the complete inhibition suggests, as proposed by earlier investigators, that the motive force of the streaming is generated at the boundary(More)
Abrupt climate change is a ubiquitous feature of the Late Pleistocene epoch. In particular, the sequence of Dansgaard-Oeschger events (repeated transitions between warm interstadial and cold stadial conditions), as recorded by ice cores in Greenland, are thought to be linked to changes in the mode of overturning circulation in the Atlantic Ocean. Moreover,(More)
A solar cell relies on its ability to turn photons into current. Because short wavelength photons are typically absorbed near the top surface of a cell, the generated charge carriers recombine before being collected. But when a layer of quantum dots (nanoscale semiconductor particles) is placed on top of the cell, it absorbs short wavelength photons and(More)
Retrieval of the bianisotropic metamaterial The retrieval methods to compute the effective permittivity and permeability of metamaterials published so far deal with isotropic permittivity and permeability. However, it is known already that the metamaterials are intrinsically anisotropic because of the orientations of the rings and rods in space, and that(More)
In the Winterberg scheme, a charge neutralized intense high-Z ion beam is axially injected into a mirror magnetic field, where it undergoes isothermal compression without significant loss of forward beam velocity. During compression , an azimuthal current is induced in the beam which then leads to ohmic heating of the beam. Simultaneously, the beam density(More)
An examination of load deflection (bulge) testing of coated and uncoated membranes by analytical and finite element methods was undertaken. The key parameters in the load-deflection behavior of a membrane were non-dimensionalized and examined to illustrate how to design test structures for materials systems of interest. Experimental and modelling procedures(More)
Study and characterization of left-handed metamaterials Many of the basic properties of left-handed (LH) media are in constrast to those typically encountered in right-handed media. For example, using a rigourous plane wave analysis of propagation and transmission into a dispersive LH medium from a RH medium, we show that power refracts at a negative angle,(More)
Tearing-mode stability properties are investigated at marginal stability (u=0) for a rotating, nonrelativistic cylindrically symmetric ion layer immersed in an axial magnetic field B0 (r)^ = [B +Bs(r)]^ z Lz 0 Z Jz The analysis is carried out within the framework of a Vlasov-fluid model in which the electrons are described as a macroscopic, cold fluid, and(More)