Development of probe-to-probe approach method for an independently controlled dual-probe scanning tunneling microscope

We developed a method of fast probe-to-probe approach for an independently controlled dual-probe scanning tunneling microscope (STM), which is essential to measure the transport property of nanostructures, without scanning electron microscopy (SEM). In the approach method, inchworm motors are used as the coarse positioning devices, which are controlled with a personal computer. The method enables an automatic approach of the probe to the other probe within a short time (typically 30 min). After the approach, a real distance between contact points of each probe tip to a sample can be measured from the overlapped part of the STM images obtained with individual probe. The approach method without SEM is also useful to measure the charge transport in the atmosphere, which will be essential for measurement of the bio molecules.     

Non‐linear finite element analysis of mechanical electrochemical phenomena in hydrated soft tissues based on triphasic theory

The well‐accepted triphasic theory for modelling the mechano‐electrochemical phenomena of charged hydrated soft tissue has been limited to infinitesimal deformation problems due to the difficulty of defining a common reference configuration for the whole tissue. In this paper, an imaginary reference configuration for soft tissue under large deformation is established based on the reference configuration of a solid matrix and a Piola transformation of the relative velocities of the fluid and ionic phases. A non‐linear finite element analysis formulation is proposed by applying a weighted residual method to the reformulated governing equations of triphasic theory reformulated in the imaginary reference configuration, with the displacement of the solid, fluid flows, ionic molar flows, hydrostatic pressure, and electrical potential as the unknown variables. After verifying the proposed finite‐element formulation by comparing the results of a linear‐confined compression problem with those obtained by the finite difference method, the numerical analysis of a three‐dimensional free‐swelling problem of articular cartilage with large deformation, and a strong non‐linearity in the material properties is carried out to reproduce the curling behaviour of articular cartilage strips in vitro when submerged in solution baths of various concentrations. The results obtained by finite element analysis are in agreement with those measured experimentally. Copyright © 2005 John Wiley & Sons, Ltd.     

Using selective precipitant for uranyl ions — Fundamental studies for evaluating the precipitant performance

We have developed a simple reprocessing process for spent FBR fuels using N-cyclohexyl-2-pyrrolidone (NCP) which has selective precipitation ability for UO₂²⁺ ions. It was confirmed that NCP has sufficient precipitation ability for UO₂²⁺ ions, decontamination capability (separation of UO₂²⁺ from simulated fission products), and resistance to γ-ray radiation in nitric acid solutions. These findings indicate that NCP is applicable to our reprocessing process. We have also evaluated performances of other precipitants such as N-n-propyl-2-pyrrolidone (NProP), N-n-butyl-2-pyrrolidone (NBP), and N-n-butyl-2-pyridone (NBPyr). It was found that higher decontamination factors (DFs) are obtained by using NProP and NBP. This can be interpreted that the hydrophobicity of NProP and NBP is lower than that of NCP. Furthermore, we have obtained an experimental result that the resistance of NBPyr to γ-ray radiation is superior to that of NCP.     

A novel chromatographic separation technique using tertiary pyridine resin for the partitioning of trivalent actinides and lanthanides

A novel chromatographic separation technique using a tertiary pyridine type resin has been applied to the partitioning of the trivalent actinides (An) and lanthanides (Ln) and several successful results have been shown. In an alcoholic hydrochloric acid system, the trivalent An were clearly separated from the Ln, while no such group separation was achieved in an alcoholic nitric acid system. On the other hand, the nitric acid system was more effective for the intragroup (i.e. individual) separation of the trivalent An and the Ln than the hydrochloric acid system. On the basis of these results, a novel concept for the partitioning of the trivalent An and Ln using the present separation technique and its flowchart have been proposed with its advantages and disadvantages.     

Variations of stress intensity factor of a semi-elliptical surface crack subjected to mixed mode loading

Maximum stress intensity factors of a surface crack usually appear at the deepest point of the crack, or a certain point along crack front near the free surface depending on the aspect ratio of the crack. However, generally it has been difficult to obtain smooth distributions of stress intensity factors along the crack front accurately due to the effect of corner point singularity. It is known that the stress singularity at a corner point where the front of 3 D cracks intersect free surface is depend on Poisson's ratio and different from the one of ordinary crack. In this paper, a singular integral equation method is applied to calculate the stress intensity factor along crack front of a 3-D semi-elliptical surface crack in a semi-infinite body under mixed mode loading. The body force method is used to formulate the problem as a system of singular integral equations with singularities of the form r ⁻³ using the stress field induced by a force doublet in a semi-infinite body as fundamental solution. In the numerical calculation, unknown body force densities are approximated by using fundamental density functions and polynomials. The results show that the present method yields smooth variations of mixed modes stress intensity factors along the crack front accurately. Distributions of stress intensity factors are indicated in tables and figures with varying the elliptical shape and Poisson's ratio.     

A single solution method for converting 2D assembly drawings to 3D part drawings

Although solid models play a central role in modern CAD systems, 2D CAD systems are still commonly used for designing products without complex curved faces. Therefore, an important task is to convert 2D drawings to solid models, and this is usually carried out manually even in present CAD systems. Many methods have been proposed to automatically convert orthographic part drawings of solid objects to solid models. Unfortunately, products are usually drawn as 2D assembly drawings, and therefore, these methods cannot be applied. A further problem is the difficult and time-consuming task of decomposing 2D assembly drawings into 2D part drawings. In previous work, the authors proposed a method to automatically decompose 2D assembly drawings into 3D part drawings, from which 2D part drawings can be easily generated. However, one problem with the proposed method was that the number of solutions could easily explode if the 2D assembly drawings became complex. Building on this work, here we describe a new method to automatically convert 2D assembly drawings to 3D part drawings, generating a unique solution for designers regardless of the complexity of the original 2D assembly drawings. The only requirement for the approach is that the assembly drawings consist of standard parts such as bars and plates. In 2D assembly drawings, the dimensions, part numbers and parts lists are usually drawn, and the proposed method utilizes these to obtain a unique solution.     

Effect of Shear Rate Distribution on Particle Aggregation in a Stirred Vessel

The modeling of particle aggregation under a simple shear flow and the extension of the model to a stirred vessel is described. The model quantitatively demonstrates the change of the number of aggregates with time for each shear rate. This number increased with higher shear rate and, conversely, the aggregate size became small when raising the shear rate. This was because aggregates were broken by the stronger shear force. The number of aggregates for different impellers was determined. The shear rate was back‐calculated from the experimentally obtained aggregate size and the model equation. This shear rate was different from that estimated from the Metzner‐Otto method, consequently, some revisions of the Metzner‐Otto equation might be necessary for its application to particle aggregation.     

Dummy humanoid robot simulating several trunk postures and abdominal shapes – Report of element technologies

Development of clothing in consideration of the shape and body function of a person with spinal cord injury is an important task. Then, a dummy robot with a deformation mechanism was developed in this study for evaluating the comfortable level of clothings. Specifically, a trunk joint mechanism and an abdominal mechanism that can realize various deformations of the abdominal area and various trunk poses were developed. The trunk joint mechanism was implemented in order to simulate the seated posture of persons with spinal cord injury. The abdominal deformation mechanism was implemented using linear actuators and rotating servomotors in order to simulate abdominal obesity of persons with spinal cord injury. Further, a tactile sensor system was developed for measuring the clothing pressure on the abdominal area and evaluating the comfort or discomfort of clothing.