Development of copper beam ducts with antechambers for advanced high-current particle storage rings

There has been continuous progress at the High Energy Accelerator Research Organization (KEK) in R&D on vacuum beam ducts adaptable to future high-current particle storage rings. Here we proposed copper beam ducts with antechambers to deal with the severe issues attributed to the high beam currents. The proposed antechamber scheme can withstand intense synchrotron radiation (SR), provide a beam duct with low beam impedance, and effectively reduce the electron cloud effect (ECE) in positron/proton rings. Several trial models were manufactured by a pressing or cold-drawn method, and assembled with electron beam welding. Special vacuum components, such as connection flanges, distributed pumps, and gate valves, were customized for the beam ducts. TiN coating on the inner surface of the beam duct was also investigated as a mitigating measure for the ECE. Trial models of the copper beam ducts were installed into the KEK B-factory (KEKB), and their performances were evaluated using real positron and electron beams.     

Phthalocyanine molecular nanowires that were prepared using porous alumina as a template: Development in the sample preparation procedure to evaluate electronic properties

We have proposed the synthesis of organic molecular nanowires using porous alumina as a template. We also proposed the use of a magnetic field to control the molecular packing structure in the nanowires. In this paper, we developed the method to evaluate the electronic properties of the nanowire of a phthalocyanine derivative that was synthesized using porous alumina as a template. The developed method facilitates the study in the organic molecular nanowires that were synthesized using templates and helps their use in future electronic devices.     

EM-based policy hyper parameter exploration: application to standing and balancing of a two-wheeled smartphone robot

This paper proposes a novel policy search algorithm called EM-based Policy Hyper Parameter Exploration (EPHE) which integrates two reinforcement learning algorithms: Policy Gradient with Parameter Exploration (PGPE) and EM-based Reward-Weighted Regression. Like PGPE, EPHE evaluates a deterministic policy in each episode with the policy parameters sampled from a prior distribution given by the policy hyper parameters (mean and variance). Based on EM-based Reward-Weighted Regression, the policy hyper parameters are updated by reward-weighted averaging so that gradient calculation and tuning of the learning rate are not required. The proposed method is tested in the benchmarks of pendulum swing-up task, cart-pole balancing task and simulation of standing and balancing of a two-wheeled smartphone robot. Experimental results show that EPHE can achieve efficient learning without learning rate tuning even for a task with discontinuities.     

Fretting fatigue behaviour of Ni-free high-nitrogen stainless steel in a simulated body fluid

Abstract

Fretting fatigue behaviour of Ni-free high-nitrogen steel (HNS) with a yield strength of about 800 MPa, which was prepared by nitrogen gas pressurized electroslag remelting, was studied in air and in phosphate-buffered saline (PBS(-)). For comparison, fretting fatigue behaviour of cold-rolled SUS316L steel (SUS316L(CR)) with similar yield strength was examined. The plain fatigue limit of HNS was slightly lower than that of SUS316L(CR) although the former had a higher tensile strength than the latter. The fretting fatigue limit of HNS was higher than that of SUS316L(CR) both in air and in PBS(-). A decrease in fatigue limit of HNS by fretting was significantly smaller than that of SUS316L(CR) in both environments, indicating that HNS has better fretting fatigue resistance than SUS316L(CR). The decrease in fatigue limit by fretting is discussed taking into account the effect of friction stress due to fretting and the additional influences of wear, tribocorrosion and plastic deformation in the fretted area.     

Binding of organic anions by synthetic supramolecular metallopores with internal Mg2+-aspartate complexes

We report that cation-selective transmembrane pores formed by synthetic p-octiphenyl beta barrels with internal aspartate residues can be transformed into anion-permeable metallopores with internal Mg(2+)-aspartate complexes. These metallopores are shown to be useful for fluorimetric sensing of a broad variety of organic anions of biological relevance such as phytate, heparin, thiamine phosphates, and adenosine triphosphate. The negligible flippase activity measurable for Mg(2+)-free pores indicates that transmembrane p-octiphenyl beta barrels do not disturb the lipid bilayer suprastructure, in other words, they form barrel-stave rather than toroidal pores.     

Genetically engineered active Qbeta replicase in rabbit reticulocyte cell-free system: a fusion protein of EF-Tu and EF-Ts is functional as the subunit of Qbeta replicase

Qbeta replicase functioning in Escherichia coli is an RNA-dependent RNA polymerase composed of one phage-coded subunit and three host-coded proteins: ribosomal protein S1, and protein elongation factors EF-Tu and EF-Ts. Qbeta replicase lacking ribosomal protein S1 (alpha-less replicase) is capable of replicating some small RNAs. We attempted to create functional alpha-less replicase by co-expression of the mRNAs that code for the subunits of alpha-less replicase in a rabbit reticulocyte cell-free translation system. Replicase activity, however, could not be detected when both EF-Tu and EF-Ts were co-expressed with the phage-coded subunit. On the other hand, active alpha-less replicase was obtained when an EF-Ts-EF-Tu fusion protein was co-expressed with the phage-coded subunit. Consequently, we succeeded in generating genetically engineered active alpha-less Qbeta replicase which functions in a eukaryotic cell-free system.     

A novel gene delivery system in plants with calcium alginate micro-beads

We have produced micrometer-sized calcium alginate beads referred to as "bio-beads" that encapsulate plasmid DNA molecules carrying a reporter gene. In order to evaluate the efficiency of the bio-beads in mediating genetic transfection, protoplasts isolated from cultured tobacco cells (BY-2) were transfected with bio-beads containing a plasmid that carries the modified green fluorescent protein gene CaMV35S-sGFP. With the bio-beads treatment, approximately ten-fold higher GFP expression was observed after 24 h incubation compared to that with the conventional method using a naked plasmid solution. Transfection was up to 0.22% efficient. These results indicate that bio-beads have a possibility for efficient transformation in plants.     

MRF-based texture segmentation using wavelet decomposed images

In recent textured image segmentation, Bayesian approaches capitalizing on computational efficiency of multiresolution representations have received much attention. Most of the previous researches have been based on multiresolution stochastic models which use the Gaussian pyramid image decomposition. In this paper, motivated by nonredundant directional selectivity and highly discriminative nature of the wavelet representation, we present an unsupervised textured image segmentation algorithm based on a multiscale stochastic modeling over the wavelet decomposition of image. The model, using doubly stochastic Markov random fields, captures intrascale statistical dependencies over the wavelet decomposed image and intrascale and interscale dependencies over the corresponding multiresolution region image.     

Thermodynamics of iron oxide in Fe x O-dilute CaO + Al2O3 + MgO + Fe x O slags at 1873 K

In order to determine the ferrous and ferric ion capacities: 3