搜索结果：Nihon Jibiinkoka Gakkai kaiho

In this paper, we prove a higher integrability result for very weak solutions of higher-order elliptic systems involving a double phase operator as the principal part. As a model case, we consider \begin{equation} \int_Ω \left( |D^m u|^{p-2}D^m u + a(x)|D^m u|^{q-2}D^m u \right) \cdot D^m \varphi = 0 \quad \text{for any } \varphi \in C_c^{\infty}(Ω), \end{equation} where $n,m \in \mathbb{N},\ n\ge 2,\,1 < p \le q < \infty,\,Ω\subset \mathbb{R}^n$ is an open set and $a:Ω\rightarrow [0,\infty)$ is a measurable function. The proof is based on a construction of an appropriate test function by the Lipschitz truncation technique, a deduction of a reverse Hölder inequality and an application of Gehring's lemma. Our contributions include estimates for weighted mean value polynomials and sharp Sobolev--Poincaré-type inequalities for the double phase operator. Our result can be viewed as a generalization with respect to the derivative order, the coefficient function and the growth conditions of the recent paper by Baasandorj, Byun and Kim (Trans. Amer. Math. Soc. 376:8733-8768,2023).

The relaxation modulus of a viscoelastic fluid can be decomposed into multiple Maxwell models and characterized by the relaxation spectrum for the relaxation time. It is empirically known that the logarithmic relaxation time is useful to express the relaxation spectrum. We use information geometry to analyze the relaxation modulus and shown that the logarithmic relaxation time is the most natural variable for the relaxation spectrum. Then we use information theory to estimate the most probable functional form for the relaxation spectrum. We show that the log-normal distribution is the information-theoretically most probable relaxation spectrum. We analyze the properties of the log-normal relaxation spectrum model and compare it with the fractional Maxwell model. The fractional Maxwell model with a small power-law exponent can be approximated as the log-normal relaxation spectrum model with a large standard deviation. We also compare the log-normal relaxation spectrum model with experimental linear viscoelasticity data for a high-density polyethylene, both at melt and solid states.

The rheological behavior of polymer melts is strongly influenced by parameters such as chain length, chain stiffness, and architecture. In particular, shear thinning, characterized by a power-law decrease in shear viscosity with increasing shear rate, has been widely investigated through molecular dynamics simulations. A central question is the connection between molecular conformation under steady flow and the resulting shear-thinning response. In this study, we employ coarse-grained molecular dynamics simulations of linear and ring polymers with varying chain stiffness to examine this relationship, with chain conformations quantified by the gyration tensor. We identified a strong correlation between the velocity-gradient direction component of the gyration tensor and shear viscosity, which exhibits a clear scaling relationship. This indicates that chain extension along the velocity-gradient direction governs the effective frictional force. Notably, this behavior emerges as a general feature, independent of chain architecture and chain stiffness. In addition, shear viscosity was found to correlate with the component of the gyration tensor corresponding to the direction that is not

The Rouse-Ham model is a simple yet useful dynamics model for an unentangled branched polymer. In this work, we study the normal modes of the Rouse-Ham type coarse-grained symmetric star polymer model. We model a star polymer by connecting multiple arm beads to a center bead by harmonic springs. In the Rouse-Ham model, the dynamics of the bead positions can be decomposed into the normal modes, which are chosen to be orthogonal to each other. Due to the existence of degenerate eigenvalues, the eigenmodes do not directly correspond to the normal modes. We propose several methods to construct the normal modes for the coarse-grained symmetric star polymer model. We show that we can construct the normal modes by using a simple permutation or the Hadamard matrix. These methods give symple and highly symmetric orthogonal modes, but work just for a special number of arms. We also show that we can construct the normal modes by using the discrete Fourier transform (DFT) matrix. This method is applicable for an arbitrary number of arms.

We analyze the stress tensor and the gyration tensor of an unentangled polymer melt under flow by using a Rouse-type single chain model. We employ the bead-spring type single chain model, in which beads interact each other via nonlinear potentials such as the finite-extensible nonlinear elasticity (FENE) potential. Beads are assumed to obey the Langevin equation with a constant friction coefficient. We derive simple yet general relations between the stress tensor and the gyration tensor for this Rouse-type model, without any additional approximations. Various formulae for rheological quantities in terms of the gyration tensor can be derived from the general relations. For example, the steady shear viscosity is governed by the gyration radius in the shear gradient direction.

On the occasion of centenary anniversary of the Great Kanto Earthquake and commencement of radio broadcasting in Japan, this study reiterates the paramount importance of medium-wave (MW) AM broadcasting in safeguarding public safety and security. Utilizing the electromagnetic principles of MW, the author has earlier developed hoop-shaped radio (HOOPRA), which is a battery-free sustainable radio receiver. This study aims to determine the maximum achievable reception distance with HOOPRA for broadcasts from public stations, such as Nihon Hoso Kyokai (NHK) JOFG (927 kHz, 5 kW) in Fukui, and NHK JOAK (594 kHz, 300 kW), and JOAB (693 kHz, 500 kW), in the Kanto region. The significance of the findings in this study is that approximately 38 million individuals in the Kanto region, residing within an 80 km radius of JOAK or JOAB, can access broadcasts using only the energy of radio waves with HOOPRA. Additionally, ~0.4 million people in Fukui, within a 15 km radius of JOFG, can potentially be recipients of the broadcast. Given that most transmitting stations operate at 5 kW nationwide, HOOPRA can be effectively utilized within a 15 km radius of each station. Moreover, these outcomes valida

Intuitive control of synthesis processes is an ongoing challenge within the domain of auditory perception and cognition. Previous works on sound modelling combined with psychophysical tests have enabled our team to develop a synthesizer that provides intuitive control of actions and objects based on semantic descriptions for sound sources. In this demo we present an augmented version of the synthesizer in which we added tactile stimulations to increase the sensation of true continuous friction interactions (rubbing and scratching) with the simulated objects. This is of interest for several reasons. Firstly, it enables to evaluate the realism of our sound model in presence of stimulations from other modalities. Secondly it enables to compare tactile and auditory signal structures linked to the same evocation, and thirdly it provides a tool to investigate multimodal perception and how stimulations from different modalities should be combined to provide realistic user interfaces.

The Rouse model with harmonic springs and the Langevin equation (Langevin-Rouse model) is widely used to describe the linear viscoelasticity of unentangled polymer melts. A similar model, in which the Langevin equation is replaced by discrete local jump dynamics (the jump-Rouse model), is also used to describe the dynamics of some systems such as entangled polymer melts. Intuitively, we expect that the Langevin- and jump-Rouse models give similar linear viscoelastic behaviors. However, the Langevin- and jump-Rouse models are not equivalent, and their linear viscoelastic behaviors can be different. In this work, we compare the shear relaxation moduli of the Langevin- and jump-Rouse model in detail. We develop a jump rate model in which the resampling ratio is tunable. By using this jump rate model, we can smoothly connect the jump-Rouse model and the Langevin-Rouse model. We perform kinetic Monte Carlo simulations to calculate the shear relaxation modulus data of the jump-Rouse model. We compare the simulation results with various numbers of beads and resampling ratios, and show that the shear relaxation moduli of the Langevin- and jump-Rouse models are similar but slightly differen

We show the linear response theory of spatial-scale-dependent relaxation moduli for overdamped Brownian particle systems. We employ the Irving-Kirkwood stress tensor field as the microscopic stress tensor field. We show that the scale-dependent relaxation modulus tensor, which characterizes the response of the stress tensor field to the applied velocity gradient field, can be expressed by using the correlation function of the Irving-Kirkwood stress tensor field. The spatial Fourier transform of the relaxation modulus tensor gives the wavenumber-dependent relaxation modulus. For isotropic and homogeneous systems, the relaxation modulus tensor has only two independent components. The transverse and longitudinal deformation modes give the wavenumber-dependent shear relaxation modulus and the wavenumber-dependent bulk relaxation modulus. As simple examples, we derive the explicit expressions for the relaxation moduli for two simple models the non-interacting Brownian particles and the harmonic dumbbell model.

We derive the stress tensor of a rigid dumbbell by using the virtual work method. In the virtual work method, we virtually apply a small deformation to the system, and relate the change of the energy to the work done by the stress tensor. A rigid dumbbell consists of two particles connected by a rigid bond of which length is constant (the rigid constraint). The energy of the rigid dumbbell consists only on the kinetic energy. Also, only the deformations which do not violate the rigid constraint are allowed. Thus we need the dynamic equations which is consistent with the rigid constraint to apply the virtual deformation. We rewrite the dynamic equations for the underdamped SLLOD-type dynamic equations into the forms which are consistent with the rigid constraint. Then we apply the virtual deformation to a rigid dumbbell based on the obtained dynamic equations. We derive the stress tensor for the rigid dumbbell model from the change of the kinetic energy. Finally, we take the overdamped limit and derive the stress tensor and the dynamic equation for the overdamped rigid dumbbell. We show that the Green-Kubo type linear response formula can be reproduced by combining the stress tensor

Direct and alternating current iontophoresis and electro-osmosis methodologies have provided new methods of transcutaneous drug delivery. A byproduct of such methods is lowering the electrical impedance of the electrode to skin contact, as conductive ions permeate the stratum corneum, the primary resistive layer of the skin. We developed a method for adapting iontophoresis to condition the electrode to skin contact, both for electrophysiological recording and electrical stimulation of body tissues. By utilizing direct current to treat electrodes with high impedance we show the effectiveness of iontopheresis as a driving force for permeation of ionic electrolyte into the skin barrier. We applied direct current (DC) levels of 50 μA to electrodes on the human head for 30 seconds with paste (Nihon Kohden Elefix) electrolyte. Typically immediately after DC treatment conditioning there was an impedance drop of 10-30%. The effect was lasting over several hours, with the paste electrolyte. These results demonstrate the feasibility of DC conditioning to reduce the set time of electrolytic solutions and to maintain good skin contact during extended recording or stimulation sessions.

A rare meteorite has revealed evidence of a massive lost world that once orbited the young Sun before being destroyed in a catastrophic collision。 The discovery suggests some early planets formed from dramatically different materials than Earth and Mars, rewriting part of the solar system’s origin story

Type 5A molecular sieves (MS) have been demonstrated to remove radon from SF$_6$ gas. This is important for ultra-sensitive SF$_6$ gas-based directional dark matter and related rare-event physics experiments, as radon can provide a source of unwanted background events. Unfortunately, commercially available sieves intrinsically emanate radon at levels not suitable for ultra-sensitive physics experiments. A method to produce a low radioactive MS has been developed in Nihon University (NU). In this work, we explore the feasibility of the NU-developed 5A type MS for use in such experiments. A comparison with a commercially available Sigma-Aldrich 5A type MS was made. The comparison was done by calculating a parameter indicating the amount of radon intrinsically emanated by the MS per unit radon captured from SF$_6$ gas. The measurements were made using a specially adapted DURRIDGE RAD7 radon detector. The NU-developed 5A MS emanated radon up to 61$\pm$9$\%$ less per radon captured (2.1$\pm$0.1)$\times 10^{-3}$, compared to the commercial Sigma-Aldrich MS (5.4$\pm$0.4)$\times 10^{-3}$, making it a better candidate for use in a radon filtration setup for future ultra-sensitive SF$_6$ gas

C:\ArsGames takes a look at the time Chris Roberts more or less made a whole movie

An unusual gravitational wave signal has renewed hopes that primordial black holes, long considered purely theoretical, may finally be within reach of discovery。 If confirmed, they could solve one of astronomy's greatest mysteries by explaining the nature of dark matter

In our talk at Nihon university symposium, we have argued that the pipi / Kpi production amplitudes F generally have different structures from those of the pipi / Kpi scattering amplitudes T from a viewpoint of generalized S matrix on the right bases, reflecting the quark-physical picture of strong interactions, and that F should be analyzed independently from T. Here we discuss the miscellaneous topics related with this argument: The conventional analyses by K matrix method, which necessarily lead to the common phases and structures through both T and F, are based on improper application of elastic unitarity to the production processes. Recent criticisms on the method of analyses of J/psi -> omega pipi and D+ -> K- pi+ pi+, which led to the existence of sigma and kappa, respectively, are also based on improper application of elastic unitarity.

Scientists are raising concerns that we may be overlooking evidence of extraterrestrial life even when it is present。 Hidden biosignatures, limitations in detection technology, and assumptions about what life should look like can all create dangerous false negatives。 The researchers say future missions should focus not only on finding life, but als

Astronomers have finally cracked the mystery of the famous “Pink Planet,” a strange world 57 light-years away that has puzzled scientists for more than a decade。 Using the James Webb Space Telescope, researchers discovered that its atmosphere contains water vapor, methane, carbon dioxide, ammonia, and something never directly confirmed before in su

It's difficult to pinpoint the moment in my life where America started to lose the plot