Superdeformed Λ\Lambda hypernuclei with antisymmetrized molecular dynamics

The response to the addition of a $\Lambda$ hyperon is investigated for the deformed states such as superdeformation in $^{41}_\Lambda$Ca, $^{46}_\Lambda$Sc and $^{48}_\Lambda$Sc. In the present study, we use the antisymmetrized molecular dynamics (AMD) model. It is pointed out that many kinds of deformed bands appear in $^{45}$Sc and $^{47}$Sc. Especially, it is found that there exists superdeformed states in $^{45}$Sc. By the addition of a $\Lambda$ particle to $^{40}$Ca, $^{45}$Sc and $^{47}$Sc, it is predicted, for the first time, that the superdeformed states exist in the hypernuclei $^{41}_\Lambda$Ca and $^{46}_\Lambda$Sc. The manifestation of the dependence of the $\Lambda$-separation energy on nuclear deformation such as spherical, normal deformation and superdeformation is shown in the energy spectra of $^{41}_\Lambda$Ca, $^{46}_\Lambda$Sc and $^{48}_\Lambda$Sc hypernuclei.Comment: 24 pages, 8 figure

Statistical potentials for RNA-protein interactions optimized by CMA-ES

Characterizing RNA-protein interactions remains an important endeavor, complicated by the difficulty in obtaining the relevant structures. Evaluating model structures via statistical potentials is in principle straight-forward and effective. However, given the relatively small size of the existing learning set of RNA-protein complexes optimization of such potentials continues to be problematic. Notably, interaction-based statistical potentials have problems in addressing large RNA-protein complexes. In this study, we adopted a novel strategy with covariance matrix adaptation (CMA-ES) to calculate statistical potentials, successfully identifying native docking poses

Influence of longitudinal structural connectivity on seismic performance of three-hinged precast arch culverts

The hinge type of precast concrete arch culvert was introduced to Japan from France in the 1990s in consideration of the saving of labor, shortening of the construction period, and high quality control of the concrete members. However, due to the 2011 off the Pacific Coast of Tohoku Earthquake (March 11, 2011), the three-hinged precast arch culverts that had been constructed in Japan at the beginning of the period when precast arch culverts were firstly introduced, suffered damage, which spoiled their serviceability. According to the extent of the damage and the type of culverts that were damaged, the longitudinal structural connectivity of the culverts was assumed to be one of the possible reasons for the reported damage mechanism. Therefore, the objective of this paper was to clarify how strongly the longitudinal structural connectivity influenced the longitudinal seismic behavior of the three-hinged arch culverts. To achieve this objective, an elasto-plastic finite element analysis was conducted with an analytical model that could capture the characteristics of the damaged culverts. Simultaneously, a penalty method with the bi-linear spring model was applied as a solution to the contact-impact problems of the precast segmental arch members. As a result, it was found that the weaker longitudinal structural connectivity in the damaged culverts allowed the torsional displacements of the arch members to induce critical damage to the arch members, namely, edge defects in the arch crown and concrete foundation. The numerical results proved the unignorable influence of the longitudinal structural connection on the possible damage to three-hinged arch culverts

Experimental investigation of bearing mechanism of closed- and open-ended piles supported by thin bearing layer using X-ray micro CT

In order to clarify the bearing mechanism of closed-ended and open-ended piles supported by a thin bearing layer, pile-loading tests are conducted on model grounds with different bearing layer thicknesses, and the soil deformation characteristics around the pile tips are observed by X-ray micro CT. In the case of open-ended piles supported by a thin bearing layer, the soil in the pile greatly displaces following the downward displacement of the soil located more deeply than the pile tip, and the soil density in the pile becomes lower than when the bearing layer thickness is sufficiently large. These characteristics probably cause lower inner friction and lower base resistance, resulting in a lower bearing capacity. When the bearing layer thickness is more than three times the pile diameter, the bearing capacity is much higher than when the bearing layer thickness is the same as the pile diameter. In addition, soil deformation which occurs is almost entirely in the bearing layer, and the changes in bearing capacity are hardly affected by the soft layer below the bearing layer. The experimental findings obtained in the present study support the idea that the criterion for the bearing layer thickness, where the influence of a thin bearing layer on the bearing capacity can be ignored, is three times the pile diameter, regardless of whether the pile tip is open or closed

Fabrication of resistively-coupled single-electron device using an array of gold nanoparticles

We demonstrated one type of single-electron device that exhibited electrical characteristics similar to those of resistively-coupled SE transistor (R-SET) at 77 K and room temperature (287 K). Three Au electrodes on an oxidized Si chip served as drain, source, and gate electrodes were formed using electron-beam lithography and evaporation techniques. A narrow (70-nm-wide) gate electrode was patterned using thermal evaporation, whereas wide (800-nm-wide) drain and source electrodes were made using shadow evaporation. Subsequently, aqueous solution of citric acid and 15-nm-diameter gold nanoparticles (Au NPs) and toluene solution of 3-nm-diameter Au NPs chemisorbed via decanethiol were dropped on the chip to make the connections between the electrodes. Current–voltage characteristics between the drain and source electrodes exhibited Coulomb blockade (CB) at both 77 and 287 K. Dependence of the CB region on the gate voltage was similar to that of an R-SET. Simulation results of the model based on the scanning electron microscopy image of the device could reproduce the characteristics like the R-SET

Gate-tuned negative differential resistance observed at room temperature in an array of gold nanoparticles

We fabricated a single-electron (SE) device using gold nanoparticles (Au NPs). Drain, source, and gate electrodes on a SiO2/Si substrate were formed using electron beam lithography (EBL) and thermal evaporation of Au. Subsequently, solutions of 3-nm-diameter and 5-nm-diameter Au NPs were dropped on the device to make current paths through Au NPs among the electrodes. Measurements of the device exhibited negative differential resistance (NDR) in the current-voltage characteristics between the drain and source electrodes at room temperature (298 K). The NDR behavior was tuned by applying a gate voltage

Numerical investigation on arching effect surrounding deep cylindrical shaft during excavation process

Predicting the inner displacements of deep vertical shafts during the excavation process has been a difficult task considering the geological, structural, and constructional influences. In fact, the two-dimensional (2D) analytical solution based on the retaining wall model remains insufficient for understanding the actual behavior during an excavation. This is because the deformation of vertical shafts becomes complicated due to the unexpected arching effect brought about by the three-dimensional (3D) flexible displacements occurring in the excavation process. Previous analytical solutions only considered the limit equilibrium. Therefore, the present study deals with a 3D soil-structure simulation by considering the displacements of a cylindrical shaft and the mechanical behavior of the surrounding soil as well as the geometry of the cylindrical structure. Moreover, this mechanical behaviors of the surrounding soil and shaft are controlled by the shaft stiffness; hence, the relationships among the shaft stiffness, mechanical behavior of the surrounding soil (in terms of earth pressure coefficient), and shaft displacement were investigated. A cylindrical model, 120 m in depth and 20 m in diameter, was positioned at the center of a sand domain, and each excavation step was performed at an interval depth of 20 m. A 3D finite difference method analysis was applied using the modified Cam-Clay (MCC) model to represent the soil behavior. As a result, the present study provides a new normalized lateral earth pressure theory for excavated shafts by considering the 3D arching effect obtained from parametric studies using various levels of shaft stiffness. From a comparison with the analytical solutions of previous studies (Terzaghi, 1943a; Prater, 1977; Cheng & Hu, 2005), it is found that the previous studies underestimated the earth pressure acting on the cylindrical shaft because they did not consider the accurate arching effect