Exit Pupil Expansion Based on Polarization Volume Grating

In this paper, we demonstrate a waveguide display structure which can realize a large field of view on a two-dimensional plane and a larger exit pupil size at the same time. This waveguide structure has three polarization volume gratings as its coupling elements. We use Zemax to simulate the effect of monochromatic and full-color two-dimensional exit pupil expansion and actually prepared a monochromatic waveguide with a two-dimensional exit pupil expansion structure. For the red, green, and blue light beams, it can achieve a large diffraction angle and can achieve diffraction efficiency of more than 70%. The waveguide structure shown can have an angle of view of 35° in the horizontal direction and 20° in the vertical direction, and an exit pupil of 18 mm long and 17 mm wide was achieved at the same time. As measured, the overall optical efficiency was measured as high as 118.3 cd/m2 per lumen with a transparency of 72% for ambient light.

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Effects of shoulder translation on lumbar moment for two dimensional modeling strategies during lifting

Occupational Ergonomics ◽

10.3233/oer-1998-1302 ◽

1998 ◽

Vol 1 (3) ◽

pp. 173-187

Author(s):

Wayne J. Albert ◽

Joan M. Stevenson ◽

Geneviève A. Dumas ◽

Roger W. Wheeler

Keyword(s):

Sagittal Plane ◽

Tracking System ◽

Vertical Direction ◽

Two Dimensional ◽

Model Type ◽

Trunk Acceleration ◽

Analysis System ◽

Trunk Orientation ◽

Shoulder Position ◽

Dynamic Link

The objectives of this study were to: 1) develop a dynamic 2D link segment model for lifting using the constraints of four sensors from an electromagnetic motion analysis system; 2) evaluate the magnitude of shoulder movement in the sagittal plane during lifting; and 3) investigate the effect of shoulder translation on trunk acceleration and lumbar moments calculated by the developed model and comparing it with two separate 2D dynamic link segment models. Six women and six men lifted loads of 2 kg, 7 kg, 12 kg and 2 kg, 12 kg, 22 kg respectively, under stoop, squat and freestyle conditions. Trunk orientation and position, as well as shoulder position were monitored during all lifts using the Polhemus FASTRAK\trdmk. Results indicated that average range of motion was 0.05 ± 0.02 m in the horizontal direction and 0.03 ± 0.02 m in the vertical direction. Shoulder position relative to T1 was located 0.07 ± 0.02 m anteriorly, and 0.02 ± 0.04 m superiorly (0.06 and 0.00 m for males and 0.08 and 0.04 m for females, respectively). To estimate the effect of shoulder motion on trunk acceleration and L5/S1 moments, three two-dimensional dynamic link segment models were developed within the constraints of the electromagnetic tracking system and compared. Trunk segment endpoints were defined as L5/S1 and either T1 or shoulder depending on model type. For trunk accelerations, average differences between models were greater than 40 deg/s² in 70.4% trunk accelerations did not translate into significantly different moment calculations between models. Average peak dynamic L5/S1 moment differences between models were smaller than 4 Nm for all lifting conditions which failed to be statistically significant (p>0.05). The model type did not have a statistically significant effect on peak L5/S1 moments. Therefore, despite important shoulder joint translations, peak L5/S1 moments were not significantly affected.

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GLOBAL EXISTENCE RESULTS FOR THE ANISOTROPIC BOUSSINESQ SYSTEM IN DIMENSION TWO

Mathematical Models and Methods in Applied Sciences ◽

10.1142/s0218202511005106 ◽

2011 ◽

Vol 21 (03) ◽

pp. 421-457 ◽

Cited By ~ 110

Author(s):

RAPHAËL DANCHIN ◽

MARIUS PAICU

Keyword(s):

Global Existence ◽

Turbulent Flows ◽

Vertical Direction ◽

Boussinesq System ◽

Navier Stokes ◽

Two Dimensional ◽

Incompressible Euler Equation ◽

Navier Stokes Equation ◽

Transport Diffusion ◽

Anisotropic Viscosity

Models with a vanishing anisotropic viscosity in the vertical direction are of relevance for the study of turbulent flows in geophysics. This motivates us to study the two-dimensional Boussinesq system with horizontal viscosity in only one equation. In this paper, we focus on the global existence issue for possibly large initial data. We first examine the case where the Navier–Stokes equation with no vertical viscosity is coupled with a transport equation. Second, we consider a coupling between the classical two-dimensional incompressible Euler equation and a transport–diffusion equation with diffusion in the horizontal direction only. For both systems, we construct global weak solutions à la Leray and strong unique solutions for more regular data. Our results rest on the fact that the diffusion acts perpendicularly to the buoyancy force.

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Thirty-two-channel dense-wavelength-division multiplexer based on cascade two-dimensional photonic crystal waveguide structure

Journal of the Optical Society of America B ◽

10.1364/josab.24.002075 ◽

2007 ◽

Vol 24 (9) ◽

pp. 2075 ◽

Cited By ~ 7

Author(s):

Yaw-Dong Wu ◽

Ke-Wei Hsu ◽

Tien-Tsorng Shih

Keyword(s):

Photonic Crystal ◽

Waveguide Structure ◽

Wavelength Division Multiplexer ◽

Two Dimensional ◽

Photonic Crystal Waveguide ◽

Wavelength Division ◽

Dimensional Photonic Crystal ◽

Two Dimensional Photonic Crystal

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Simple and rapid CD4 testing based on large-field imaging system composed of microcavity array and two-dimensional photosensor

Biosensors and Bioelectronics ◽

10.1016/j.bios.2014.08.051 ◽

2015 ◽

Vol 67 ◽

pp. 350-355 ◽

Cited By ~ 5

Author(s):

Tatsuya Saeki ◽

Yuriko Sugamura ◽

Masahito Hosokawa ◽

Tomoko Yoshino ◽

Tae-kyu Lim ◽

...

Keyword(s):

Imaging System ◽

Large Field ◽

Two Dimensional ◽

Field Imaging ◽

Cd4 Testing

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Ultrathin full color visor with large field of view based on multilayered metasurface design

Digital Optics for Immersive Displays ◽

10.1117/12.2315594 ◽

2018 ◽

Cited By ~ 2

Author(s):

Ori Avayu ◽

Ran Ditcovski ◽

Tal Ellenbogen

Keyword(s):

Field Of View ◽

Large Field ◽

Full Color

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Emerging Artificial Two-Dimensional van der Waals Heterostructures for Optoelectronics

Smart Nanosystems for Biomedicine, Optoelectronics and Catalysis ◽

10.5772/intechopen.88433 ◽

2020 ◽

Author(s):

Hongcheng Ruan ◽

Yu Huang ◽

Yuqian Chen ◽

Fuwei Zhuge

Keyword(s):

Material Properties ◽

2D Materials ◽

Van Der Waals ◽

Optoelectronic Devices ◽

Vertical Direction ◽

Two Dimensional ◽

Device Application ◽

Optical Memories ◽

Optoelectronic Applications ◽

Transfer Method

Two-dimensional (2D) materials are attracting explosive attention for their intriguing potential in versatile applications, covering optoelectronics, electronics, sensors, etc. An attractive merit of 2D materials is their viable van der Waals (VdW) stacking in artificial sequence, thus forming different atomic arrangements in vertical direction and enabling unprecedented tailoring of material properties and device application. In this chapter, we summarize the latest progress in assembling VdW heterostructures for optoelectronic applications by beginning with the basic pick-transfer method for assembling 2D materials and then discussing the different combination of 2D materials of semiconductor, conductor, and insulator properties for various optoelectronic devices, e.g., photodiode, phototransistors, optical memories, etc.

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Equilibration of Two-Dimensional Double-Diffusive Intrusions

Journal of Physical Oceanography ◽

10.1175/jpo3000.1 ◽

2007 ◽

Vol 37 (3) ◽

pp. 625-643 ◽

Cited By ~ 11

Author(s):

Julian Simeonov ◽

Melvin E. Stern

Keyword(s):

Equilibrium State ◽

Mixed Layer ◽

Vertical Direction ◽

Maximum Velocity ◽

Reynolds Numbers ◽

Horizontal Gradient ◽

Two Dimensional ◽

Salinity Gradients ◽

Gravity Acceleration ◽

Mixed Layers

Abstract This paper considers the equilibration of lateral intrusions in a doubly diffusive fluid with uniform unbounded basic-state gradients in temperature and salinity. These are density compensated in the horizontal direction and finger favorable in the vertical direction. Previous nonlinear studies of this effect have qualitative and quantitative limitations because of their fictitious parameterizations of the weak “turbulence” that arises. Here, two-dimensional direct numerical simulations (DNS) that resolve scales from the smallest to the intrusive are used to predict the equilibrium state. This is achieved by numerically tilting the x–z computational box so that the mean intrusion is represented by a mode with no lateral variation, but smaller-scale 2D eddies comparable to the intrusion thickness are resolved. The DNS show that the initial plane wave intrusion evolves to an equilibrium state containing both a salt finger interface and a diffusive interface, surrounded by well-mixed layers. The inversion of the horizontally averaged density in the mixed layer is negligibly small, but the salt finger buoyancy flux produces large transient density inversions that drive the mixed layer convection. For the considered values of horizontal/vertical gradients, the calculations yield small Cox numbers and buoyancy Reynolds numbers [comparable to those measured in staircases during the Caribbean-Sheets and Layers Transects (C-SALT) program]. An important testable result is the time-averaged maximum velocity of the fastest-growing intrusion Umax = 18.0 (Σ*z/Σ*x)+1/2KT(gΘ*z/νKT)1/4. Here Θ*z is the undisturbed vertical temperature gradient in buoyancy units, Σ*z and Σ*x are the corresponding vertical and horizontal salinity gradients, g is the gravity acceleration, and ν and KT are the respective values of the molecular viscosity and heat diffusivity. The paradoxical inverse dependence on the horizontal gradient results from the assumption that the latter is unbounded.

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