Road traffic noise reduction of drainage pavement with small air gaps among grains is well known. However, traffic flow over many years fills those gaps with mud and sand, thereby degrading the noise reduction effect. To regain that effect, cleansing or reconstructing the pavement is necessary after precise assessment of the air gaps. For that purpose, acoustical diagnoses of drainage pavement are proposed and test results are introduced. One method is to check sound absorption of the pavement surface, which normally has high absorption near frequencies of 1 kHz, which is related to the reduction of road traffic noise. The use of a particle velocity sensor together with a microphone greatly simplifies measurements and judgments. Another analysis method is based on sound propagation through air gaps in the pavement. Transmission characteristics clearly indicate pavement conditions. Low-attenuation sound transmissions are shown in a wide frequency range below 1 kHz for sound air gaps, and weak transmissions in a narrow frequency range are shown when air gaps are filled. These acoustic diagnostic methods are effective in investigating porous drainage pavement.
We demonstrate the generation of a coherent water window x ray by extending the plateau region of high-order harmonics under a neutral-medium condition. The maximum harmonic photon energies attained are 300 and 450 eV in Ne and He, respectively. Our proposed generation scheme, combining a 1.6 microm laser driver and a neutral Ne gas medium, is efficient and scalable in output yields of the water window x ray. Thus, the precept of the design parameter for a single-shot live-cell imaging by contact microscopy is presented.
The photoabsorption cross-section of an ion immersed in a plasma is studied on the basis of the Thomas–Fermi approximation for the equilibrium electron distribution and Bloch's classical hydrodynamic model for collective motion of the electrons. The frequency-dependent cross-section scales with the nuclear charge, and depends strongly on the plasma density and temperature. An approximation of the frequency dependence is constructed with the aid of sum rules and Padé approximants.
In this research, we used a 135 MeV/nucleon carbon-ion beam to irradiate a biological sample composed of fresh chicken meat and bones, which was placed in front of a PAGAT gel dosimeter, and compared the measured and simulated transverse-relaxation-rate (R2) distributions in the gel dosimeter. We experimentally measured the three-dimensional R2 distribution, which records the dose induced by particles penetrating the sample, by using magnetic resonance imaging. The obtained R2 distribution reflected the heterogeneity of the biological sample. We also conducted Monte Carlo simulations using the PHITS code by reconstructing the elemental composition of the biological sample from its computed tomography images while taking into account the dependence of the gel response on the linear energy transfer. The simulation reproduced the experimental distal edge structure of the R2 distribution with an accuracy under about 2 mm, which is approximately the same as the voxel size currently used in treatment planning.
We report the discovery of diffuse hard (1–5 keV) X-ray emission around Jupiter in a deep 160 ks Suzaku X-ray Imaging Spectrometer data. The emission is distributed over ∼16 × 8 Jovian radius and spatially associated with the radiation belts and the Io Plasma Torus (IPT). It shows a flat power-law spectrum with a photon index of 1.4 ± 0.2 with the 1–5 keV X-ray luminosity of (3.3 ± 0.5)×1015 erg s−1. We discussed its origin and concluded that it seems to be truly diffuse, although a possibility of multiple background point sources cannot be completely rejected with a limited angular resolution. If it is diffuse, the flat continuum indicates that X-rays arise by the nonthermal electrons in the radiation belts and/or the IPT. The synchrotron and bremsstrahlung models can be rejected from the necessary electron energy and X-ray spectral shape, respectively. The inverse-Compton scattering off solar photons by ultra-relativistic (several tens MeV) electrons can explain the energy and the spectrum but the necessary electron density is ≳10 times larger than the value estimated from the empirical model of Jovian charge particles.
Recent developments of ultrafast laser pulse techniques enable us to study the subpicosecond scale dynamics out of thermal equilibrium. Multiple temperature models are frequently used to describe such dynamics where the total system is divided into subsystems each of which is in local thermal equilibrium. Typical examples include the electron-lattice two temperature model and electron-spin-phonon three temperature model. We present the exact analytical solutions of linear multiple temperature model, based on the Fourier series expansion, and discuss their properties for the case of the two and three temperature models. The solutions are linear combinations of "eigenmodes" characterized by the wave vector $\mathbf{q}$ and the well-defined mode lifetime. The eigenmode picture enables us to explore the hierarchical structure of models with respect to space, time and the coupling parameter. We also find diffusion modes unique to the three temperature model which unveils the rich physics in spite of the simplicity of the model. We prove that the eigensystem in this model is non-positive definite, which assures that the mode lifetime is always well-defined. This property clearly characterizes the model.
We present attosecond dynamics of electron-electron correlation-driven knock-up/down process following photoionization of excited helium. Its time scale is linked to the time for the outgoing inner electron to traverse the orbit of the outer electron.
Time-dependent coupled-cluster method with time-varying orbital functions, called time-dependent optimized coupled-cluster (TD-OCC) method, is formulated for multielectron dynamics in an intense laser field. We have successfully derived the equations of motion for CC amplitudes and orthonormal orbital functions based on the real action functional, and implemented the method including double excitations (TD-OCCD) and double and triple excitations (TD-OCCDT) within the optimized active orbitals. The present method is size extensive and gauge invariant, a polynomial cost-scaling alternative to the time-dependent multiconfiguration self-consistent-field method. The first application of the TD-OCC method of intense-laser driven correlated electron dynamics in Ar atom is reported.
We demonstrate experimental evidence of the dramatic enhancement effect in a process of high-order harmonic generation. The harmonic yield generated from He atoms increased by a factor of 4000 with booster high-order harmonics from Xe.
