Prismatic Research Articles

Intermittent Exotropia Treatment with Dichoptic Visual Training Using a Unique Virtual Reality Platform.

We evaluated the effect of dichoptic visual training based on a unique virtual reality (VR) platform mounted display in patients with intermittent exotropia (IXT). A total of 25 IXT patients (8 men, 17 women) with a mean age of 12.3 years (range, 5-39 year) were recruited. The Hirschberg test, prism and alternate cover testing (with accommodative targets for fixation at 33 cm in all patients), perceptual eye position (PEP), and stereopsis were evaluated after 1, 3, and 6 months of dichoptic visual neuroplasticity training with a computer-controlled perceptual examination evaluation system. Data collected before and after training were evaluated using SPSS software. After 6 months of perceptual training, a new order stereopsis was established, and eye positions were improved in all 25 patients. After training for 1 and 6 months, the horizontal PEP pixels were much lower than those pretraining, respectively (Δ1-0 = -0.53, p = 0.028; Δ6-0 = -0.80, p = 0.018). There was no statistically significant difference between pretraining and 3 months after training in horizontal PEP (Δ3-0 = -0.29, p = 0.370). There was no significant difference between pretraining and post-training in vertical PEP (p > 0.05). There were significant differences between pretraining and post-training in the cornea's optical reflection and prism diopters (p < 0.01). Dichoptic visual neuroplasticity training based on a VR platform is an effective nonsurgical treatment in patients with IXT. With the VR treatment, the degree of strabismus and stereopsis was improved in IXT patients. Perceptual training with VR can remove obstacles in the visual processing channel and repair defects in visual function. The clinical manifestations of improvement were the decrease in the degree of strabismus and the re-establishment of stereopsis.

Design, analysis and optimization of Hex4, a new 2R1T overconstrained parallel manipulator with actuation redundancy

SUMMARYPMs with two rotations and one translation (2R1T) have been used as skeletons in various advanced manufacturing equipment where high accuracy and stiffness are basic requirements. Considering the advantages of redundant actuation and overconstrained structure, such as reduced singularities and improved stiffness, a new 2R1T overconstrained PM with actuation redundancy, called Hex4, is proposed in this paper. This is a 2-PUR/2-RPU PM (wherePdenotes an actuated prismatic joint, U a universal joint, and R a revolute joint) that is actuated by four prismatic joints. Compared with some existing 2R1T overconstrained PMs with actuation redundancy, the main advantage of the proposed PM is that the heavy motors of two limbs are mounted on the base to reduce the movable mass and improve dynamic response. First, mobility analysis, inverse kinematics, and velocity analysis are presented. Then, the local transmission index and good transmission workspace are used to evaluate the motion/force transmissibility of the Hex4 PM. The variation tendencies of the two indices with different link parameters are investigated. The singularity is then discussed by considering the motion/force transmissibility. Finally, link parameters are optimized to obtain an improved good transmission workspace. It is shown that the proposed PM has a good potential for high precision applications.

Prisms and Posture: Baropodometric and Stabilometric changes after Arismatic Adaptation

Prisms and Posture: Baropodometric and Stabilometric changes after Arismatic Adaptation

Color mixing with four prisms redux

Color mixing with four prisms redux

Temperature stresses in prismatic substances at radiant-convective heat exchange

Temperature stresses in prismatic substances at radiant-convective heat exchange

Prismatic perspectives on the pre-Islamic empires of Persia

Prismatic perspectives on the pre-Islamic empires of Persia

Measuring the Extinction Index of Dielectric Films Using Frustrated Total Internal Reflectance Spectroscopy

Various methods of measuring the coefficient of light attenuation in optical coatings are considered. It is shown that the dimensionless extinction index of a coating made of a weakly absorbing film-forming material can be measured using a special attachment based on a parallelepiped-shaped optical prism. Parameters of the proposed attachment are calculated so that it could be arranged inside standard spectrophotometers.

Effects of adding sisal and glass fibers on the mechanical behaviour of concrete polymer

In this study, we investigated the influence of the addition of sisal and glass fibres on the mechanical properties of polymer concrete (PC). These types of concrete are used in many modern civil engineering applications. The prismatic specimens sized according to ASTM C580-02 were elaborated with a PC constituted by 14% constant mass of polyester resin matrix, a granular skeleton based on sand and powder marble. The reinforcement with 60% sand and 26% marble powder adopted in this investigation is the best formulation found in previous authors work. This composition was reinforced by 1 and 2% of sisal and glass fibres, the first one having lengths of 6 mm or 12 mm, however, the second unidirectional cut into bands. These specimens were subjected to 3-point bending monotonic loading. The results obtained were discussed and compared with those obtained for control beams without fibres reinforcement. It is important to note that the incorporation of the glass fibre contributes to an increase of the ultimate load of the polymer composite material produced, however, the addition of the sisal fibre lead to its decreases. In addition, the incorporation of 2% of sisal fibre having 6 mm length leads to a reduction of 26% of the mass of the specimens.

광학 프리즘과 렌즈를 이용한 시감각 시기능훈련이 굴절성 약시안의 안기능 증진에 미치는 영향

광학 프리즘과 렌즈를 이용한 시감각 시기능훈련이 굴절성 약시안의 안기능 증진에 미치는 영향

Thermal behavior of a commercial prismatic Lithium-ion battery cell applied in electric vehicles

Thermal behavior of a commercial prismatic Lithium-ion battery cell applied in electric vehicles

Patterning and manipulating microparticles into a three-dimensional matrix using standing surface acoustic waves

A method based on standing surface acoustic waves (SSAWs) is proposed to pattern and manipulate microparticles into a three-dimensional (3D) matrix inside a microchamber. An optical prism is used to observe the 3D alignment and patterning of the microparticles in the vertical and horizontal planes simultaneously. The acoustic radiation force effectively patterns the microparticles into lines of 3D space or crystal-lattice-like matrix patterns. A microparticle can be positioned precisely at a specified vertical location by balancing the forces of acoustic radiation, drag, buoyancy, and gravity acting on the microparticle. Experiments and finite-element numerical simulations both show that the acoustic radiation force increases gradually from the bottom of the chamber to the top, and microparticles can be moved up or down simply by adjusting the applied SSAW power. Our method has great potential for acoustofluidic applications, building the large-scale structures associated with biological objects and artificial neuron networks.

A Quadrilateral Prism of Self-invisibility

A hollow quadrilateral prism consists of four rigid right triangular prisms laid asymmetrically in a V-like shape. Each triangular prism has a base face which is an obtuse scalene triangle, and the front and rear lateral faces are covered with a reflective material of visible light. The front and rear lateral faces of the four right triangular prisms face each other forming an asymmetrical channel between them, which is filled with a transparent material. The hollow quadrilateral prism reflects incident light in sequence by the reflective lateral faces of right triangular prisms. It is configured to make a good portion of the frame invisible to the driver of an automobile and renders driving safer and more comfortable.

Note: Tandem Kirkpatrick-Baez microscope with sixteen channels for high-resolution laser-plasma diagnostics.

Multi-channel Kirkpatrick-Baez (KB) microscopes, which have better resolution and collection efficiency than pinhole cameras, have been widely used in laser inertial confinement fusion to diagnose time evolution of the target implosion. In this study, a tandem multi-channel KB microscope was developed to have sixteen imaging channels with the precise control of spatial resolution and image intervals. This precise control was created using a coarse assembly of mirror pairs with high-accuracy optical prisms, followed by precise adjustment in real-time x-ray imaging experiments. The multilayers coated on the KB mirrors were designed to have substantially the same reflectivity to obtain a uniform brightness of different images for laser-plasma temperature analysis. The study provides a practicable method to achieve the optimum performance of the microscope for future high-resolution applications in inertial confinement fusion experiments.

Transsaccadic transfer of distortion adaptation in a natural environment.

Spatially varying distortions in optical elements-for instance prisms and progressive power lenses-modulate the visual world disparately in different visual areas. Saccadic eye movements in such a complexly distorted environment thereby continuously alter the retinal location of the distortions. Yet the visual system achieves perceptual constancy by compensating for distortions irrespective of their retinal relocations at different fixations. Here, we assessed whether the visual system retains its plasticity to distortions across saccades to attain stability. Specifically, we tapped into reference frames of geometric skew-adaptation aftereffects to evaluate the transfer of retinotopic and spatiotopic distortion information across saccades. Adaptation to skew distortion of natural-image content was tested at retinotopic and spatiotopic locations after a saccade was executed between adaptation and test phases. The skew-adaptation information was partially transferred to a new fixation after a saccade. Significant adaptation aftereffects were obtained at both retinotopic and spatiotopic locations. Conceivably, spatiotopic information was used to counterbalance the saccadic retinal shifts of the distortions. Therefore, distortion processing in a natural visual world does not start anew at each fixation; rather, retinotopic and spatiotopic skew information acquired at previous fixations are preserved to mediate stable perception during eye movements.

All about Prisms- Easy to Understand

All about Prisms- Easy to Understand

Labeling crossed prisms with a condition at distance two

Labeling crossed prisms with a condition at distance two

Sufficient conditions for prisms to produce orthogonal image orientation functions without spectral dispersion

Sufficient conditions for prisms to produce orthogonal image orientation functions without spectral dispersion

Axial load detection in compressed steel beams using FBG-DSM sensors

Nondestructive testing methods are required to assess the condition of civil structures and formulate their maintenance programs. Axial force identification is required for several structural members of truss bridges, pipe racks, and space roof trusses. An accurate evaluation of in situ axial forces supports the safety assessment of the entire truss. A considerable redistribution of internal forces may indicate structural damage. In this paper, a novel compressive force identification method for prismatic members implemented using static deflections is applied to steel beams. The procedure uses the Euler–Bernoulli beam model and estimates the compressive load by using the measured displacement along the beam\'s length. Knowledge of flexural rigidity of the member under investigation is required. In this study, the deflected shape of a compressed steel beam is subjected to an additional vertical load that was short-term measured in several laboratory tests by using fiber Bragg grating–differential settlement measurement (FBG–DSM) sensors at specific cross sections along the beam\'s length. The accuracy of midspan deflections offered by the FBG–DSM sensors provided excellent force estimations. Compressive load detection accuracy can be improved if substantial second-order effects are induced in the tests. In conclusion, the proposed method can be successfully applied to steel beams with low slenderness under real conditions.

Eliminating diplopia in the 9 gaze directions using optical prism and occlusion films

Eliminating diplopia in the 9 gaze directions using optical prism and occlusion films

Измерение показателя экстинкции диэлектрических пленок на основе спектроскопии нарушенного полного внутреннего отражения

AbstractVarious methods of measuring the coefficient of light attenuation in optical coatings are considered. It is shown that the dimensionless extinction index of a coating made of a weakly absorbing film-forming material can be measured using a special attachment based on a parallelepiped-shaped optical prism. Parameters of the proposed attachment are calculated so that it could be arranged inside standard spectrophotometers.