Inherent Negative Refraction on Acoustic Branch of Two Dimensional Phononic Crystals

Guided by theoretical predictions, we have demonstrated experimentally the existence of negative refraction on the lowest two (acoustic) passbands (shear and longitudinal modes) of a simple two dimensional phononic crystal consisting of an isotropic stiff (aluminum) matrix and square- patterned isotropic compliant (PMMA) circular inclusions. At frequencies and wave vectors where the refraction is negative, the effective mass density and the effective stiffness tensors of the crystal can be positive-defnite, and that, this is an inherent property of phononic crystals with an isotropic stiff matrix containing periodically distributed isotropic compliant inclusions. The equi-frequency contours and energy ux vectors as fuctions of the phase-vector components, reveal a rich body of refractive properties that can be exploited to realize, for example, beam splitting, focusing, and frequency filtration on the lowest passbands of the crystal where the dissipation is the least. By proper selection of material and geometric parameters these phenomena can be realized at remarkably low frequencies (large wave lengths) using rather small simple two-phase unit cells. Keywords: Doubly periodic phononic crystals, acoustic branch negative refraction, beam splitting, focusing, imaging, frequency filtration at large wave length

Prediction for Irregular Ocean Wave and Floating Body Motion by Regularization: Part 1. Irregular Wave Prediction

Ocean waves can be explained in terms of many factors, including wave spectrum, which has the characteristics of wave height and periodicity, directional spreading function, which has a directional property, and random phase, which randomly represents a certain property. Under the assumption of a linear system, ocean waves show irregular behaviours, which can be observed in the forms of wave spectrum, directional spreading function, and complex phase calculations using the method of linear superposition. Ocean waves, which include a variety of periodic elements, exhibit direct proportionality between their period and propagation velocity. The purpose of this study was to understand the phase components of the period and to make exact calculations on the deterministic phase in order to make predictions on ocean waves. However, measurements of actual ocean waves exist only in the form of information on wave elevation, so we faced an inverse problem of having to analyse this information and calculate the deterministic phase. Regularization was used as part of the solution, and various methods were used to obtain stable values

Prediction for Irregular Ocean Wave and Floating Body Motion by Regularization: Part 2. Motion Prediction

In the analysis of the motion of a floating body, the domains can broadly be divided into the frequency domain and the time domain. The essence of the frequency domain analysis lies in calculating the hydrodynamic coefficient from the equation of motion, which has six degrees of freedom, by applying several methods. In this research, Bureau Veritas’s “HydroStar” software was used, and the comparison and the verification were carried out by experiments. For the time domain analysis, we used an existing method proposed by Cummins and made motion predictions by using deterministic random phases calculated in the time domain calculations of the excitation force. Lastly, the potential of wave and motion predictions was verified through the data obtained from a motion analysis experiment using a tension leg platform in the context of irregular waves

SuperChat: Dialogue Generation by Transfer Learning from Vision to Language using Two-dimensional Word Embedding and Pretrained ImageNet CNN Models

The recent work of Super Characters method using two-dimensional word embedding achieved state-of-the-art results in text classification tasks, showcasing the promise of this new approach. This paper borrows the idea of Super Characters method and two-dimensional embedding, and proposes a method of generating conversational response for open domain dialogues. The experimental results on a public dataset shows that the proposed SuperChat method generates high quality responses. An interactive demo is ready to show at the workshop.Comment: 5 pages, 2 figures, 1 table. Accepted by CVPR2019 Language and Vision Worksho

Wave Run-Up Phenomenon on Offshore Platforms: Part 1. Tension Leg Platform

This study reports on an extensive experimental campaign carried out to evaluate non-linear waves applied to offshore structures in extreme marine environments. An offshore tension leg platform (TLP) model was used to observe the waves around a fixed-type offshore structure. The wave amplitude measured in the experiments of this study was indicated as a wave run-up ratio. Both the first-order analysis and the analysis of the entire wave amplitude were described. The experimental results were compared with the calculations from a potential-based code in order to verify the effectiveness of the developed technology

Gas-Filled Phospholipid Nanoparticles Conjugated with Gadolinium Play a Role as a Potential Theragnostics for MR-Guided HIFU Ablation

To develop a long-circulating theragnostics, meaning therapeutics and diagnostics for MR-guided HIFU ablation, we designed and prepared Gd-C5F12-phospholipid nanobubbles (PLNs) 30–100 nm in diameter. The biochemical and physical characterization of Gd-C5F12-PLNs were performed. Since Gd-C5F12-PLN-50 (Φ = 50 nm) and Gd-C5F12-PLN-100 (Φ = 100 nm) enhanced the hyperthermal effect of HIFU size- and concentration-dependently in a tissue-mimicking phantom, its circulation, distribution, tumor accumulation and tumor ablation were examined in tumor-bearing mice. The plasma-half life of Gd-C5F12-PLNs was longer than 1.5 hrs. Gd-C5F12-PLNs mainly accumulated in the liver and the spleen, suggesting that they are slowly secreted through the hepatobiliary pathway. Monitored by the T1 signal intensity of MR, Gd-C5F12-PLNs accumulated in tumor tissues for 8 hours in mice. HIFU with Gd-C5F12-PLN-100 showed the increased tumor ablation area as compared with HIFU alone. The results suggest that Gd-C5F12-PLNs exhibit a potential theragnostics for MR-guided HIFU ablation