scholarly journals Trade‐off between threshold gain and directionality of emission for modes of two‐dimensional eccentric microring lasers analysed using lasing eigenvalue problem

2021 ◽  
Author(s):  
Anna I. Repina ◽  
Alina O. Oktyabrskaya ◽  
Alexander O. Spiridonov ◽  
Ilya V. Ketov ◽  
Evgenii M. Karchevskii
Keyword(s):  
Eigenvalue Problem ◽  
Two Dimensional ◽  
Trade Off ◽  
Threshold Gain

scholarly journals Overcoming the trade-off between Voc and Jsc: Asymmetric chloro-substituted two-dimensional benzo[1,2-b:4,5-b′]dithiophene-based polymer solar cells

2019 ◽  
Vol 162 ◽  
pp. 746-754 ◽  
Author(s):  
Pengjie Chao ◽  
Longzhu Liu ◽  
Jianfei Qu ◽  
Qiming He ◽  
Shenglong Gan ◽  
...  
Keyword(s):  
Solar Cells ◽  
Polymer Solar Cells ◽  
Two Dimensional ◽  
Trade Off

scholarly journals Upscaling with the dynamic two-layer classification concept (D2C): TreeMig-2L, an efficient implementation of the forest-landscape model TreeMig

2015 ◽  
Vol 8 (7) ◽  
pp. 5535-5575
Author(s):  
J. E. M. S. Nabel
Keyword(s):  
Vegetation Dynamics ◽  
Climatic Changes ◽  
Discrete Models ◽  
Similarity Criteria ◽  
Forest Landscape ◽  
Two Dimensional ◽  
Landscape Model ◽  
Trade Off ◽  
Forest Landscape Model ◽  
Spatio Temporal

Abstract. Models used to investigate impacts of climatic changes on spatio-temporal vegetation dynamics need to balance required accuracy with computational feasibility. To enhance the computational efficiency of these models, upscaling methods are required that maintain key fine-scale processes influencing vegetation dynamics. In this paper, an adjustable method – the dynamic two-layer classification concept (D2C) – for the upscaling of time- and space-discrete models is presented. D2C aims to separate potentially repetitive calculations from those specific to single grid cells. The underlying idea is to extract processes that do not require information about a grid cell's neighbourhood to a reduced-size non-spatial layer, which is dynamically coupled to the original two-dimensional layer. The size of the non-spatial layer is thereby adaptive and depends on dynamic classifications according to pre-specified similarity criteria. I present how D2C can be used in a model implementation on the example of TreeMig-2L, a new, efficient version of the intermediate-complexity forest-landscape model TreeMig. To discuss the trade-off between computational expenses and accuracy, as well as the applicability of D2C, I compare different model stages of TreeMig-2L via simulations of two different application scenarios. This comparison of different model stages demonstrates that applying D2C can strongly reduce computational expenses of processes calculated on the new non-spatial layer. D2C is thus a valuable upscaling method for models and applications in which processes requiring information about the neighbourhood constitute the minor share of the overall computational expenses.

Free Convection Thermal Interaction Between 2D Components Mounted on a Vertically Oriented PCB

2002 ◽  
Author(s):  
D. Newport ◽  
T. Dalton ◽  
M. Davies
Keyword(s):  
Boundary Layer ◽  
Effective Conductivity ◽  
Ball Grid Array ◽  
Velocity Fields ◽  
Two Dimensional ◽  
Thermal Interaction ◽  
Trade Off ◽  
Layer Flow ◽  
Digital Moiré ◽  
Temperature And Velocity Fields

In this paper, measurements are presented of the temperature and velocity fields about two PCBs, with an array of five equally spaced two dimensional ribs. The ribs are two dimensional approximations of the Super Ball Grid Array (SuperBGA) package from Amkor electronics. The temperature and Nusselt number distributions are measured using Digital Moire´ Subtraction Interferometry and PIV is used to measure the velocity field. The effect of substrate conductivity is examined, and the level of thermal interaction is quantified. It is found that substrate conductivity significantly alters the induced boundary layer flow and also the recirculating vortex structure external to it. It is also found that there is a trade-off between a downstream component being heated by the thermal energy of the plume from a lower component, and cooled by the kinetic energy of that plume. The spacing to length ratio, above which the cooling effect is greater, is three for components mounted on a board with a high effective conductivity (15 W/m K). The ratio is greater than three for PCBs with lower effective conductivities. Previous work in the literature indicates a ratio greater than four for components mounted flush with an adiabatic substrate.

Speed-accuracy trade-off in the performance of pointing movements in different directions in two-dimensional space

2000 ◽  
Vol 134 (1) ◽  
pp. 21-31 ◽  
Author(s):  
N. Smyrnis ◽  
I. Evdokimidis ◽  
T.S. Constantinidis ◽  
G. Kastrinakis
Keyword(s):  
Dimensional Space ◽  
Two Dimensional ◽  
Trade Off ◽  
Pointing Movements ◽  
Speed Accuracy

The three-dimensional stability of boundary-layer flow over compliant walls

1992 ◽  
Vol 238 ◽  
pp. 537-577 ◽  
Author(s):  
K. S. Yeo
Keyword(s):  
Boundary Layer ◽  
Eigenvalue Problem ◽  
Growth Rates ◽  
Isotropic Material ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Material Anisotropy ◽  
Compliant Walls ◽  
Tollmien Schlichting ◽  
Disturbance Growth

This paper examines the linear stability of the Blasius boundary layer over compliant walls to three-dimensional (oblique) disturbance wave modes. The formulation of the eigenvalue problem is applicable to compliant walls possessing general material anisotropy. Isotropic-material walls and selected classes of anisotropic-material walls are studied. When the properties of the wall are identical with respect to all oblique wave directions, the stability eigenvalue problem for unstable three-dimensional wave modes may be reduced to an equivalent problem for two-dimensional modes. The results for isotropic-material walls show that three-dimensional Tollmien–Schlichting instability modes are more dominant than their two-dimensional counterparts when the walls are sufficiently compliant. The critical Reynolds number for Tollmien-Schlichting instability may be given by three-dimensional modes. Furthermore, for highly compliant walls, calculations based solely on two-dimensional modes are likely to underestimate the maximum disturbance growth factor needed for transition prediction and correlation. However, because the disturbance growth rates on highly compliant walls are much lower than those on a rigid wall, significant delay of transition may still be possible provided compliance-induced instabilities are properly suppressed. Walls featuring material anisotropy which have reduced stiffness to shear deformation in the transverse and oblique planes are also investigated. Such anisotropy is found to be effective in reducing the growth rates of the three-dimensional modes relative to those of the two-dimensional modes.

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