40 research outputs found
Integral equation method for the electromagnetic wave propagation in stratified anisotropic dielectric-magnetic materials
We investigate the propagation of electromagnetic waves in stratified
anisotropic dielectric-magnetic materials using the integral equation method
(IEM). Based on the superposition principle, we use Hertz vector formulations
of radiated fields to study the interaction of wave with matter. We derive in a
new way the dispersion relation, Snell's law and reflection/transmission
coefficients by self-consistent analyses. Moreover, we find two new forms of
the generalized extinction theorem. Applying the IEM, we investigate the wave
propagation through a slab and disclose the underlying physics which are
further verified by numerical simulations. The results lead to a unified
framework of the IEM for the propagation of wave incident either from a medium
or vacuum in stratified dielectric-magnetic materials.Comment: 14pages, 3figure
Orbital-angular-momentum dependent speckles for spatial mode sorting and multiplexed data transmission
Characterizing the orbital angular momentum (OAM) of a vortex beam is
critically important for OAM-encoded data transfer. However, in typical
OAM-based applications where vortex beams transmit through diffusers, the
accompanying scattering effect tends to be either deliberately prevented, or
characterized and then modulated actively based on complex wavefront shaping
and interferometry techniques. Here, we aim to investigate the characteristics
of blurred speckles obtained after a vortex beam transmits through a ground
glass diffuser. It is theoretically and experimentally demonstrated that a
cross-correlation annulus can be identified by implementing the
cross-correlation operation between speckle patterns corresponding to vortex
beams with different OAM values. Besides, it is worth noting that, the size of
the cross-correlation annulus is determined by the absolute value of the
topological charge difference between the two corresponding vortex beams. Based
on this mechanism, the OAM modes can be easily sorted from the incoherently
measured OAM-dependent speckles as well as their cross-correlation.
Furthermore, to make full use of the orthogonal feature of the OAM-dependent
speckles, demultiplexing of OAM-encoded data transfer is verified using a
ground glass diffuser. Both 8-bit grayscale and 24-bit RGB OAM-encoded data
transfers are carried out in experiments with superior error rates. We can
conclude that the OAM-dependent speckles can be not only utilized as a
competitive candidate for the OAM mode sorting function in a simple way but
also provide an efficient method for the demultiplexing of OAM-encoded data
transfer in a practical application
Effects of overtreatment with different attachment positions on maxillary anchorage enhancement with clear aligners: a finite element analysis study
Abstract Background The effect of attachment positions on anchorage has not been fully explored. The aim of the present study is to analyze the effect of overtreatment with different anchorage positions on maxillary anchorage enhancement with clear aligners in extraction cases. Methods Models of the maxilla and maxillary dentition were constructed and imported into SOLIDWORKS software to create periodontal ligament (PDL), clear aligners, and attachments. Attachment positions on second premolars included: without attachment (WOA), buccal attachment (BA), and bucco-palatal attachment (BPA). Overtreatment degrees were divided into five groups (0°, 1°, 2°, 3°, 4°) and added on the second premolars. The calculation and analysis of the displacement trends and stress were performed using ANSYS software. Results Distal tipping and extrusion of the canines, and mesial tipping and intrusion of the posterior teeth occurred during retraction. A strong anchorage was achieved in cases of overtreatment of 2.8° with BA and 2.4° with BPA. Moreover, the BPA showed the best in achieving bodily control of the second premolars. When the overtreatment was performed, the canines and first molars also showed reduced tipping trends with second premolars attachments. And the stress on the PDL and the alveolar bone was significantly relieved and more evenly distributed in the BPA group. Conclusions Overtreatment is an effective means for anchorage enhancement. However, the biomechanical effect of overtreatment differs across attachment positions. The BPA design performs at its best for stronger overtreatment effects with fewer adverse effects
Additional file 2 of Effects of overtreatment with different attachment positions on maxillary anchorage enhancement with clear aligners: a finite element analysis study
Supplementary Material
Additional file 1 of Effects of overtreatment with different attachment positions on maxillary anchorage enhancement with clear aligners: a finite element analysis study
Supplementary Material
Additional file 4 of Effects of overtreatment with different attachment positions on maxillary anchorage enhancement with clear aligners: a finite element analysis study
Supplementary Material
Additional file 3 of Effects of overtreatment with different attachment positions on maxillary anchorage enhancement with clear aligners: a finite element analysis study
Supplementary Material