38 research outputs found
Guiding optical flows by photonic crystal slabs made of dielectric cylinders
We investigate the electromagnetic propagation in two-dimensional photonic
crystals, formed by parallel dielectric cylinders embedded a uniform medium.
The frequency band structure is computed using the standard plane-wave
expansion method, while the propagation and scattering of the electromagnetic
waves are calculated by the multiple scattering theory. It is shown that within
partial bandgaps, the waves tend to bend away from the forbidden directions.
Such a property may render novel applications in manipulating optical flows. In
addition, the relevance with the imaging by flat photonic crystal slabs will
also be discussed.Comment: 5 pages, 5 figure
Bandgaps in the propagation and scattering of surface water waves over cylindrical steps
Here we investigate the propagation and scattering of surface water waves by
arrays of bottom-mounted cylindrical steps. Both periodic and random
arrangements of the steps are considered. The wave transmission through the
arrays is computed using the multiple scattering method based upon a recently
derived formulation. For the periodic case, the results are compared to the
band structure calculation. We demonstrate that complete band gaps can be
obtained in such a system. Furthermore, we show that the randomization of the
location of the steps can significantly reduce the transmission of water waves.
Comparison with other systems is also discussed.Comment: 4 pages, 3 figure
高鉄棒け上りの写真分析
One skilled and eight unskilled subjects were selected as subjects in this study. They performed the kip on the high bar. The cinematographic analysis was undertaken to determine the characteristic results of the kip in the skilled and the unskilled. The following positions were defined for the phasic analysis : (A) end of back swing, (B) greater trochanter below the bar, (C) initiation of hip flexion, (D) end of forward swing, (E) initiation of hip extension, (F) greater trochanter below the bar, (G) greater trochanter at level of the bar, and (H) finish. The skilled completed the whole kip movements. However, the unskilled subjects could not carry their bodies to rise to the support position. In the skilled, the ankles were lifted to the bar. The unskilled lifted the knees, instead of the ankles, to the bar. Earlier bringing the legs up to the bar was observed in the unskilled than in the skilled. The skilled performer moved his body with the straight arms over the whole kip. The unskilled, however, lifted their bodies to the bar by bending the elbow joints during from the point (B) to the (F). The extension of the hip, or bringing the legs up for the kip, were started earlier in the unskilled subjects than in the skilled
Advances in modelling of biomimetic fluid flow at different scales
The biomimetic flow at different scales has been discussed at length. The need of looking into the biological surfaces and morphologies and both geometrical and physical similarities to imitate the technological products and processes has been emphasized. The complex fluid flow and heat transfer problems, the fluid-interface and the physics involved at multiscale and macro-, meso-, micro- and nano-scales have been discussed. The flow and heat transfer simulation is done by various CFD solvers including Navier-Stokes and energy equations, lattice Boltzmann method and molecular dynamics method. Combined continuum-molecular dynamics method is also reviewed
Study of the phase equilibrium of the oligo(ethylene oxide)-water system by differential thermal analysis
Tissue doppler imaging (E/e\u27) and pulmonary capillary wedge pressure in patients with severe aortic stenosis
Objective: Although American and European consensus statements advocate using the ratio of the transmitral E velocity and tissue Doppler early diastolic mitral annular velocity (E/e\u27) in the assessment of left-sided heart filling pressures, recent reports have questioned the reliability of this ratio to predict left atrial pressures in a variety of disease states. The authors hypothesized that there is a clinically significant correlation between E/e\u27 and pulmonary capillary wedge pressure (PCWP) in patients with severe aortic stenosis.
Design: Retrospective cohort study.
Participants: The study comprised 733 consecutive patients with severe aortic stenosis who underwent transcatheter aortic valve replacement for severe aortic stenosis.
Interventions: None.
Measurements and main results: PCWP and E/e\u27ave (average of the lateral and medial annulus tissue Doppler velocities) were measured with a pulmonary artery catheter and transthoracic echocardiography during preprocedural evaluation. Patients were grouped by left ventricular ejection fraction (LVEF) ≥50% and LVEF \u3c50%. Spearman rank correlation, analysis of variance, and t and chi-square tests were used to analyze the data. Seventy-nine patients met the inclusion criteria. There was no significant correlation between E/e\u27ave and PCWP (n = 79, Spearman r = 0.096; p = 0.3994). This correlation did not improve when ventricular function was considered (LVEF \u3c50%: n = 11, Spearman r = -0.097; p = 0.776 and LVEF ≥50%: n = 68, Spearman r = 0.116; p = 0.345). There was no statistically significant difference in mean PCWP between each range of E/e\u27ave.
Conclusion: A clinically relevant relationship between E/e\u27 and PCWP was not observed in patients with severe aortic stenosis
Tissue Doppler Imaging (E/e\u27) and Pulmonary Capillary Wedge Pressure in Patients With Severe Aortic Stenosis.
OBJECTIVE: Although American and European consensus statements advocate using the ratio of the transmitral E velocity and tissue Doppler early diastolic mitral annular velocity (E/e\u27) in the assessment of left-sided heart filling pressures, recent reports have questioned the reliability of this ratio to predict left atrial pressures in a variety of disease states. The authors hypothesized that there is a clinically significant correlation between E/e\u27 and pulmonary capillary wedge pressure (PCWP) in patients with severe aortic stenosis.
DESIGN: Retrospective cohort study.
PARTICIPANTS: The study comprised 733 consecutive patients with severe aortic stenosis who underwent transcatheter aortic valve replacement for severe aortic stenosis.
INTERVENTIONS: None.
MEASUREMENTS AND MAIN RESULTS: PCWP and E/e\u27
CONCLUSION: A clinically relevant relationship between E/e\u27 and PCWP was not observed in patients with severe aortic stenosis