Large magnetoresistivity of sputtered Al-(O or N)-Bi alloys

Application of the sputtering technique to (Al₂O₃)_xBi_100–x and (AIN)_x Bi_100–x (x = 0 to 100%) has been found to result in the formation of a duplex material consisting of hexagonal bismuth particles dispersed finely and homogeneously in amorphous Al_xO_y and Al_xN_y matrices. The particle size and interparticle distance of the bismuth phase were about 5 to 140nm and 5 to 35 nm. The duplex alloys have high electrical resistivities ranging from 1.82 × 10³ to 3.16 × 10⁵ cm combined with a negative temperature-dependent resistivity of 148 to 342% of ₂₇₃. Furthermore, all the Al-O-Bi and Al-N-Bi alloys have been found to exhibit a positive magnetoresistive change and the maximum value, (H), at 4.2 K and 7.5T reaches 5.85 × 10⁴ cm for (Al-O)_65.7Bi_34.3 and 1.99 × 10⁵ cm for (Al-N)_69.7 Bi_30.3. The large magnetoresistivities are probably due to the unique sputtered structure consisting of metallic bismuth particles with a long mean free path of electrons embedded finely and homogeneously in amorphous Al_xO_y or Al_xN_y matrix, resulting in the large difference of the relaxation times (different mobilities) of electron carriers. It has thus been demonstrated that the oxide- or nitride-based composite materials exhibiting large magnetoresistivities, which cannot be achieved in metallic composite materials, are obtained by sputtering simultaneously Al₂O₃ or AIN and bismuth which is immiscible to aluminium.     

Construction of living cellular automata using the Physarum plasmodium

The plasmodium of Physarum polycephalum is a unicellular and multinuclear giant amoeba that has an amorphous cell body. To clearly observe how the plasmodium makes decisions in its motile and exploratory behaviours, we developed a new experimental system to pseudo-discretize the motility of the organism. In our experimental space that has agar surfaces arranged in a two-dimensional lattice, the continuous and omnidirectional movement of the plasmodium was limited to the stepwise one, and the direction of the locomotion was also limited to four neighbours. In such an experimental system, a cellular automata-like system was constructed using the living cell. We further analysed the exploratory behaviours of the plasmodium by duplicating the experimental results in the simulation models of cellular automata. As a result, it was revealed that the behaviours of the plasmodium are not reproduced by only local state transition rules; and for the reproduction, a kind of historical rule setting is needed.     

Recent progress in thermal analysis of polymers: experimental techniques and a new aspect of temperature in measurement of material properties

Thermal analysis has been utilized in polymer research for a long time and its usefulness is widely recognized. High‐performance commercial instruments have driven significant progress in the thermal studies of polymers. On the other hand, new experimental instruments have been developed in laboratories as well. In this paper attention is paid to the latter category. The laboratory‐made instrument focused on the target material and/or phenomena provides data that are not available from other techniques. Experiments using the temperature modulation technique, which has been successfully utilized in laboratory‐made instruments, are introduced in this paper. The temperature modulation technique reveals a new aspect of temperature useful for studies of material properties. © 2016 Society of Chemical Industry     

Bag of local landscape features for fitness landscape analysis

Evolutionary computation is a research field dealing with black-box and complex optimization problems whose fitness landscapes are usually unknown in advance. It is difficult to select an appropriate evolutionary algorithm and parameters for a given problem due to the black-box setting although many evolutionary algorithms have been developed. In this context, several landscape features have been proposed and their usefulness examined for understanding the problem. In this paper, we propose a novel feature vector by focusing on the local landscape in order to characterize the fitness landscape. The proposed landscape features are a vector form and composed of a histogram of quantized local landscape features. We introduce two implementation methods of this concept, called the bag of local landscape patterns (BoLLP) and the bag of evolvability (BoEvo). The BoLLP uses the fitness pattern of the neighbors of a certain candidate solution, and the BoEvo uses the number of better candidate solutions in the neighbors as the local landscape features. Furthermore, the hierarchical versions of the BoLLP and the BoEvo, concatenated feature vectors with different sample sizes, are considered to capture the landscape characteristic with various resolutions. We extract the proposed landscape feature vectors from well-known continuous optimization benchmark functions and the BBOB benchmark function set to investigate their properties; the visualization of the proposed landscape features, clustering and running time prediction experiments are conducted. Then the effectiveness of the proposed landscape features for the fitness landscape analysis is discussed based on the experimental results.     

Inhibition of char deposition using a particle bed in heating section of supercritical water gasification

Supercritical water gasification (SCWG) has attracted attention as a technology for utilizing wet biomass. We used a fluidized bed of alumina particles to prevent blockage of a SCWG reactor. A glucose solution was heated in the reactor with and without fluidized alumina particles. In the absence of alumina particles, char particles formed homogeneously in the reactor, but the use of a fluidized bed resulted in accumulation of char particles at the reactor’s exit rather than inside the reactor. Therefore, the fluidized bed was effective at preventing blockage of the reactor. However, the alumina particles did not remove deposits from the reactor’s walls. Instead, the fluidized bed caused larger char particles to form, preventing their adhesion to the reactor’s wall.     

Dynamic Changes in Reactive Oxygen Species in the Shoot Apex Contribute to Stem Cell Death in Arabidopsis thaliana

In monocarpic plants, stem cells are fated to die. However, the potential mechanism of stem cell death has remained elusive. Here, we reveal that the levels of two forms of reactive oxygen species (ROS), superoxide anion free radical (O2·−) and hydrogen peroxide (H₂O₂), show dynamic changes in the shoot apex during the plant life cycle of Arabidopsis thaliana. We found that the level of O2·− decreased and disappeared at four weeks after bolting (WAB), while H₂O₂ appeared at 3 WAB and showed a burst at 5 WAB. The timing of dynamic changes in O2·− and H₂O₂ was delayed for approximately three weeks in clv3-2, which has a longer lifespan. Moreover, exogenous application of H₂O₂ inhibited the expression of the stem cell determinant WUSCHEL (WUS) and promoted the expression of the developmentally programmed cell death (dPCD) marker gene ORESARA 1 (ORE1). These results indicate that H₂O₂ triggers an important signal inducing dPCD in stem cells. Given that O2·− plays roles in maintaining WUS expression and stem cell activity, we speculate that the dynamic shift from O2·− to H₂O₂ in the shoot apex results in stem cell death. Our findings provide novel insights for understanding ROS-mediated regulation during plant stem cell death.     

浸没式光刻的优势和可行性

浸没式光刻通过高折射率的液体充入透镜底部和片子之间的空间使光学系统的数值孔径具有显著的优势。在193nm曝光系统中,水(折射率为1.44)被选作最佳的浸入液体。通过成像模拟,现已证明ArF穴193nm雪浸没式光刻(NA=1.05～1.23)与F2穴157nm雪干法穴NA=0.85～0.93雪光刻具有几乎相同的成像性能。结合流体力学和热模拟结果,讨论了ArF浸没式曝光设备的优势和可行性。     

Construction of an error map of rotary axes on a five-axis machining center by static R-test

This paper proposes an efficient and automated scheme to calibrate error motions of rotary axes on a five-axis machining center by using the R-test. During a five-axis measurement cycle, the R-test probing system measures the three-dimensional displacement of a sphere attached to the spindle in relative to the machine table. Location errors, defined in ISO 230-7, of rotary axes are the most fundamental error factors in the five-axis kinematics. A larger class of error motions can be modeled as geometric errors that vary depending on the angular position of a rotary axis. The objective of this paper is to present an algorithm to identify not only location errors, but also such position-dependent geometric errors, or “error map,” of rotary axes. Its experimental demonstration is presented.     

The electronic structures of fluorinated polyacetylenes. A design of new organic polymer alternatives to polyacetylene

The electronic structures of polyfluoroacetylene and polydifluoroacetylene are discussed on the basis of the tight-binding LCAO-SCF-MO calculations under the CNDO/2 approximations. A method of preparation of these polymers is also proposed. If they can be successfully prepared, they will be promising candidates for new electric conducting materials as alternatives to polyacetylene.