Evaluation of Fracture Toughness for Wood-Epoxy Adhesive System under External Shear Force

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。Fracture Toughness G_c of Wood-Epoxy adhesive system under external shear force was evaluated by employing the experimental compliance method based on the Griffith-Irwin fracture theory. Invariability of G_c with the different glue line length was tolerably recognized and the representative value of G_c for the above system was about 0.25 (cm・kg/cm^2) throughout the series of glue line thickness tested. Fracture mode and stress distribution were discussed with some helps of Finite Element Method

Well-width dependence of valley splitting in Si/SiGe quantum wells

The valley splitting in Si two-dimensional electron systems is studied using Si/SiGe single quantum wells (QWs) with different well widths. The energy gaps for 4 and 5.3 nm QWs, obtained from the temperature dependence of the longitudinal resistivity at the Landau level filling factor $\nu=1$, are much larger than those for 10 and 20 nm QWs. This is consistent with the well-width dependence of the bare valley splitting estimated from the comparison with the Zeeman splitting in the Shubnikov-de Haas oscillations.Comment: 3 pages, 2 figure

Metallic Behavior of Cyclotron Relaxation Time in Two-Dimensional Systems

Cyclotron resonance of two-dimensional electrons is studied at low temperatures down to 0.4 K for a high-mobility Si/SiGe quantum well which exhibits a metallic temperature dependence of dc resistivity $\rho$. The relaxation time $\tau_{\rm CR}$ shows a negative temperature dependence, which is similar to that of the transport scattering time $\tau_t$ obtained from $\rho$. The ratio $\tau_{\rm CR}/\tau_t$ at 0.4 K increases as the electron density $N_s$ decreases, and exceeds unity when $N_s$ approaches the critical density for the metal-insulator transition.Comment: 4 pages, 3 figure

Adipose-derived Mesenchymal Stem Cells Improve Both Spontaneous Pain and Allodynia in a Rat Neuropathic Pain Model

Purpose：Several studies investigated the efficacy of transplanting adipose-derived mesenchymal stem cells（ADMSCs）in the treatment of neuropathic pain in animals. However, these studies evaluated the effects of ADMSCs transplantation by assessing the mechanical allodynia but not spontaneous pain. Here, we verify whether ADMSCs transplantation improves spontaneous pain in a rat model of neuropathic pain. Methods：ADMSCs were isolated from rat adipose tissue and cultured. Chronic constriction injury（CCI） model rats were created by surgical maneuver. A total of 20 F344 rats underwent surgery and were divided into 2 groups, the ADMSCs group and the control group. One week after CCI surgery, ADMSCs were transplanted into the epineurium of the damaged nerve. The effects of ADMSCs transplantation were evaluated by the number of spontaneous pain-related behaviors and the degree of mechanical allodynia. The degree of mechanical allodynia was assessed with the von-Frey filament test. Results：No rats died during the experiments and all CCI model rats were established successfully. ADMSCs transplantation improved mechanical allodynia on and after 7-day post-transplantation and spontaneous pain on and after 21-day post-transplantation with the statistically significant differences. These improvement effects were observed until 6-week post-transplantation in mechanical allodynia and 5-week post-transplantation in spontaneous pain. Conclusion：ADMSCs transplantation improved not only mechanical allodynia but also spontaneous pain. ADMSCs transplantation may be an effective treatment for neuropathic pain in clinical practice

Deep Adversarial Reinforcement Learning With Noise Compensation by Autoencoder

We present a new adversarial learning method for deep reinforcement learning (DRL). Based on this method, robust internal representation in a deep Q-network (DQN) was introduced by applying adversarial noise to disturb the DQN policy; however, it was compensated for by the autoencoder network. In particular, we proposed the use of a new type of adversarial noise: it encourages the policy to choose the worst action leading to the worst outcome at each state. When the proposed method, called deep Q-W-network regularized with an autoencoder (DQWAE), was applied to seven different games in an Atari 2600, the results were convincing. DQWAE exhibited greater robustness against the random/adversarial noise added to the input and accelerated the learning process more than the baseline DQN. When applied to a realistic automatic driving simulation, the proposed DRL method was found to be effective at rendering the acquired policy robust against random/adversarial noise

Signatures of self-organized criticality in spontaneous walking behavior of Porcellio scaber

The 11th International Symposium on Adaptive Motion of Animals and Machines. Kobe University, Japan. 2023-06-06/09. Adaptive Motion of Animals and Machines Organizing Committee.Poster Session P6

One-Step Holographic Photoalignment for Twisted Nematic Liquid Crystal Gratings

Liquid crystal gratings, in which liquid crystal molecules are periodically aligned, are fabricated by highly efficient and practical one-step holographic photoalignment method using a photocrosslinkable polymer liquid crystal (PCLC). This method is an innovative fabrication technique for liquid crystal grating containing a twisted nematic alignment, which does not require a conventional complex fabrication process. In this chapter, three types of liquid crystal gratings with twisted nematic alignment are fabricated. Periodic director distributions of these liquid crystal gratings are analyzed based on the elastic continuum theory and observed experimentally using a polarized light optical microscope. Furthermore, the polarization diffraction properties were measured by illumination with a visible laser beam. The resultant liquid crystal gratings exhibit various polarization diffraction properties depending on the director distributions and the polarization states of the incident beams. These polarization diffraction properties are well explained by theoretical analysis based on Jones calculus. These resultant liquid crystal gratings exhibit great potential for application as a diffractive optical element that can simultaneously control the various parameters of the light wave, such as amplitude, polarization states, and propagation direction