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Developing self-organised swarm systems capable of adapting to environmental changes as well as to dynamic situations is a complex challenge. An efficient labour division model, with the ability to regulate the distribution of work among swarm robots, is an important element of this kind of system. This paper extends the popular response threshold model and proposes a new adaptive response threshold model (ARTM). Experiments were carried out in simulation and in real-robot scenarios with the aim of studying the performance of this new adaptive model. Results presented in this paper verify that the extended approach improves on the adaptability of previous systems. For example, by reducing collision duration among robots in foraging missions, our approach helps small swarms of robots to adapt more efficiently to changing environments, thus increasing their self-sustainability (survival rate). Finally, we propose a minimal version of ARTM, which is derived from the conclusions drawn through real-robot and simulation results.

In recent years, phosphor-converted white light-emitting diodes (pc-WLED) have great attention due to long lifetime and low power consumption compared to traditional lighting source. The most popular method to fabricate the pc-WLEDs is a combination of blue LED chips (GaN) and yellow phosphor (Y3Al5O12:Ce3+), which shows high luminescence intensity. However, such pc-WLED does not have high color rendering property due to the lack of red color emission component. In order to solve the problem and obtain warmer colored pc-WLEDs, it is efficient to incorporate a red phosphor in the pc-WLED. It is known that Mn-doped phosphor have been studied because of their broad excitation band in UV-blue region and their deep red emission. Among the oxide basis phosphors, several materials such as Mn-doped CaAl12O19 [1] and Mg2TiO4 [2] were reported with good luminescence property. To increase the emission efficiency, additional doping into such Mn-doped oxide phosphors were examined. The remarkable enhancement of the emission intensity was reported for Mg co-doping in Mn-doped CaAl12O19 [3]. However, the mechanism why such enhancement was achieved by co-doping has not yet been fully understood. In this study, influence of additional doping of divalent ions, such as Mg2+, Zn2+ and Cd2+, on the red-emission intensity of Mn-doped CaAl12O19 is investigated. All the samples were synthesized with conventional solid-state reaction method by changing divalent ions concentration. Crystal structure of the synthesized samples was characterized with the powder X-ray diffraction (XRD) technique. To determine the charge state and the local environment of Mn ions, the Electron Spin Resonance (ESR) spectra were observed. The observed photoluminescence spectra of non-doped and Cd2+, Mg2+, Zn2+ co-doped CaAl12O19:Mn are shown in Fig. 1. In all cases, it is shown that divalent ions dopings could enhance the emission intensity, among which Mg2+ doping shows the largest enhancement. In the observed ESR spectra of non-doped and Cd2+, Mg2+, Zn2+ co-doped CaAl12O19:Mn, six peaks derived from hyper fine structure of Mn4+ could be seen in all the samples. It is noted that Mg and Zn co-doping significantly affects the spectral profiles, whereas only slight change was observed in Cd co-doped one. This indicates that Mg and Zn co-doping influence on local structure of Mn. In order to understand the effect of divalent ions doping on the enhancement of the red emission intensity, the first principles calculations within a density functional theory (DFT) have been also performed. As it is well known that the local environment of Mn ions is quite important on the emission intensity, local environment of Mn ions in CaAl12O19 were examined by substituting Mn ions at five crystallographically independent Al sites using the Vienna Ab initio Simulation Package (VASP)[4]. Using the same method, influence of additional dopings of divalent ions are investigated. In the conventional DFT calculations with local density approximation (LDA) or generalized gradient approximation (GGA) the band gap is always underestimated. As there are some methods developed recently to obtain more accurate band gap, for the electronic structure analysis, the modified Becke-Johnson potential by Tran and Blaha (TB-mBJ) [5] implemented in WIEN2k package [6] was employed here. In addition, Hubbard U correction on the d electron state is adopted to represent the strong correlation between d-electrons on Mn ions, which cannot be fully included in TB-mBJ. Acknowledgement This work was partially supported by the Joint Research Center for Environmentally Conscious Technologies in Materials Science (project No. 30009, 30012, 31008, and 31017) at ZAIKEN, Waseda University. References [1] T. Murata et al., J. Lumines. 114 (2005) 207. [2] J. Long et al., Mater. Res. Bull. 85 (2016) 234. [3] M.G. Brik et al., J. Alloys Comp. 509 (2011) 1452. [4] G. Kresse, J. Furthmuller, Comput. Mater. Sci. 6 (1996) 15. [5] F. Tran and P. Blaha, Phys. Rev. Lett. 102 (2009) 226401. [6] P. Blaha, K. Schwarz, G.K.H. Madsen, D. Kvasnicka, J. Luitz, WIEN2k, An Augmented Plane Wave+Local Orbitals Program for Calculating Crystal Properties, Karlheinz Schwarz Technische Universitat, Wien, Austria, 2001. Figure 1

Most of the current phosphor materials are prepared by doping dilute amount of rare-earth or transition metal ions, which act as emission center, in matrix materials. Among such phosphors, rare-earth doped oxides show good properties such as high luminescence and high stability for long term use, etc. However, due to the limitation of the rare-earth elements in the earth, rare-earth free phosphor materials have been strongly demanding, and therefore such materials have been extensively investigated these years. Although there are wide varieties of dopants for such rare-earth free phosphors, Mn4+ doped phosphor materials, which show red emission, are one of the most attractive materials. In order to design new phosphors doped with Mn ions, it is essential to know the local environment of the doped Mn ions in an atomic scale and the electronic structures of Mn-doped materials. Although the local environment analysis is mandatory, such analysis is very difficult for dilute dopants. In the current study, local environment analysis of Mn ions doped in some oxides were carried out by using the X-ray absorption near edge structure (XANES) measurements and the electronic structure calculations for such materials have been performed with the first principles calculations. All the samples were fabricated with the conventional solid-state reaction method changing the concentration of Mn ions and/or matrix oxides, such as CaTiO3, CaZrO3, CaSnO3, CaAl12O19, Mg2TiO4 and so on. Crystal structures of the synthesized materials were characterized with powder X-ray diffraction technique. Mn K- and L- XANES spectra were observed at BL9C of KEK-PF in the transmission mode and BL4B in UVSOR in total electron yield mode, respectively. Theoretical XANES spectra to be compared with the experimental ones were prepared with the WIEN2k package [1]. Prior to the detailed electronic structure calculations, geometry optimizations were carried out computationally to investigate the local environment of the doped Mn ions in the matrix oxides by the first principles calculations within a density functional theory level using the Vienna Ab-initio Simulation Package, VASP [2]. The electronic structures of the Mn-doped materials after above geometry optimizations were investigated with modified Becke-Johnson potential [3], which was recently developed electron-electron correlation functional and implemented in WIEN2k package is accurate for the band-gap estimation of the wide variety of semiconductors. Acknowledgement This work was partially supported by the Joint Research Center for Environmentally Conscious Technologies in Materials Science (project No. 30009, 30012, 31008, and 31017) at ZAIKEN, Waseda University. References [1] P. Blaha, K. Schwarz, G.K.H. Madsen, D. Kvasnicka, J. Luitz, WIEN2k, An Augmented Plane Wave+Local Orbitals Program for Calculating Crystal Properties, Karlheinz Schwarz Technische Universitat, Wien, Austria, 2001. [2] G. Kresse, J. Furthmuller, Comput. Mater. Sci. 6 (1996) 15. [3] F. Tran and P. Blaha, Phys. Rev. Lett. 102 (2009) 226401.

Organic-inorganic lead halide perovskites have attracted great attention as light absorbers of hybrid perovskite solar cells (PSCs). Among the organic-inorganic hybrid perovskites (OIHP), CH3NH3PbI3 (MAPbI3) and CH(NH2)2PbI3 (FAPbI3) have been extensively studied as light absorbers of PSCs. PSCs are expected to be next-generation solar cells due to their high conversion efficiency and low fabrication cost. However, power conversion efficiency of PSCs declines shortly after being fabricated, because of degradation of hybrid perovskite layers. OIHP such as FAPbI3 decomposes easily into PbI2 and transforms to d-phase from a-phase, which is suitable for the application to the solar cells, under ambient condition [1]. It was reported that partial substitution of inorganic monovalent ions such as Cs and Rb ions at FA site is effective to improve the phase stability of a-phase [2]. This can be easily explained by the Goldschmidt tolerance factor [3], which is an indicator for the stability of perovskite structure. Ionic radius of FA is too large, but the partial substitution of Cs or Rb can make the average ionic radius smaller than that of FA, which stabilizes the a-phase. For example, d-phase is the stable phase in FAPbI3 at ambient condition, which transforms to a-phase above 165 ℃ [4]. However, the partially substituted FAxCsyPbI3 is stable even at room temperature. The perovskite layers are grown on electron transport layers (ETL) such as TiO2, SnO2, and ZnO by spin-coating method. Although TiO2 has been widely used for ETL of PSCs, SnO2 has been also applied to ETL because of its excellent band energy level alignment with that of the perovskite layers and its higher electron mobility [5]. In addition, devices using SnO2 as ETL decrease their photoconversion efficiency more slowly than using TiO2 under ambient condition, which suggests that decomposition processes of the perovskites on TiO2 and SnO2 is different [6]. In the fabrication process of ETL, SnO2 is annealed after spin-coating. If the annealing temperature is high above 450 degrees Celsius, rutile structured crystalline SnO2 thin film grows, while only amorphous structured SnO2 thin film appear by the low temperature annealing, such as between 150 and 200 degrees Celsius. Some studies have shown that amorphous SnO2 fabricated by low temperature process increases performances of devices compared with crystalline SnO2 [7, 8]. In this study, FA1-xCsxPb(I1-yBry)3 was synthesized by spin-coating method on the SnO2 layers and annealed at various temperature to evaluate the dependence of SnO2 substrate structure on the stability of perovskite layers. Stability of all the samples here synthesized were monitored with the X-ray diffraction technique at 0, 1, 2, 3, 4, 24, 96 and 168 hours kept in air after fabrications. Fig.1 shows the intensity of diffraction peaks of d-FAPbI3 (100) as a function of time. Although the intensity of d-FAPbI3 peaks increased in FA0.85Cs0.15PbI3 and FA0.85Cs0.15Pb(I0.85Br0.15)3 formed on SnO2 annealed at 450 ℃ , it unchanged in FA0.85Cs0.15PbI3 and FA0.85Cs0.15Pb(I0.85Br0.15)3 on SnO2 annealed at 180 degree Celsius. These results sugessts that the stability of a-FAPbI3 grown on SnO2 annealed at 180 degree Celsius is better than that annealed at 450 degree Celsius. The crystal structures of SnO2 annealed at 200, 300 and 400 degree Celsius were characterized with the Glazing Incident X-ray diffraction technique. The surface morphology of SnO2 were obsereved with the scannning electron microscope, which suggest SnO2 surface became rougher as annealing temperature increased. The chemical composition of the surface of SnO2 layers were investigated by Auger electron spectroscopy, from which Cl peaks were obsererved in SnO2 annealed at 200 ℃ and 300 ℃, while Cl were not detected in SnO2 annealed at 400 degree Celsius. [1] T. Leijtens et al., J. Mater. Chem. A.5, 11483-11500 (2017) [2] M. Saliba et al., Science 354, 206-209 (2016) [3] C. C. Stoumpos et al., Acc. Chem. Res. 48, 2791-2802 (2015) [4] Z. Li et al., Chem. Mater. 28, 284-292 (2016) [5] L. B. Xiong et al., J. Mater. Chem. A.4, 8374-8383 (2016) [6] Q. Dong et al., Nano Energy 40, 336-344 (2017) [7] W. J. Ke et al., J. Mater. Chem. A.3, 24163-24168 (2015) [8] K.-H Jung et al., J. Mater. Chem. A.5, 24790-24803 (2017) Figure 1

We propose a low-cost and high immersive infinity walking system with HMD and all directional load balance, which enables to present walking sensation for a user in VR environments. By using a device supporting user’s thighs during walking, our system enables a user to shift the center of gravity of body toward any walking direction like dynamic walking in real environments. Although many studies have proposed infinity walking systems based on a treadmill, a stepping method, a sliding method, and etc., there are several limitations to use these systems in practice. For example, the treadmill-based walking system is large and high-cost. The stepping method is known to be a low-cost method, but it is difficult for a user to shift the center of gravity of body toward a walking direction. The walking sensation provided by the sliding method may not be natural, because user’s feet move backward during walking. Therefore, we develop a low-cost and high immersive infinity walking system with HMD and all directional load balance that can provide the realistic walking sensation with a user.

Arterial stiffness is often assessed in clinical medicine, because it is not only an important factor in the pathophysiology of blood circulation but also a marker for the diagnosis and the prognosis of cardiovascular diseases. Many parameters have so far been proposed to quantitatively represent arterial stiffness and distensibility, such as pressure-strain elastic modulus (Ep), stiffness parameter (β), pulse wave velocity (PWV), and vascular compliance (Cv). Among these, PWV has been most frequently applied to clinical medicine. However, this is dependent on blood pressure at the time of measurement, and therefore it is not appropriate as a parameter for the clinical evaluation of arterial stiffness, especially for the studies on hypertension. On the contrary, stiffness parameter β is an index reflecting arterial stiffness without the influence of blood pressure. Recently, this parameter has been applied to develop a new arterial stiffness index called cardio-ankle vascular index (CAVI). Although this index is obtained from the PWV between the heart and the ankle, it is essentially similar to the stiffness parameter β, and therefore it does not depend on blood pressure changes during the measurements. CAVI is being extensively used in clinical medicine as a measure for the evaluation of cardiovascular diseases and risk factors related to arteriosclerosis. In the present article, we will explain the theoretical background of stiffness parameter β and the process to obtain CAVI. And then, the clinical utility of CAVI will be overviewed by reference to recent studies.

Many human augmentation devices have been developed in the past few decades, but lots of them neglected the importance of well-timed assistance, which commonly leads to problems like lowered perfor...

The Rrs1 protein plays an essential role in the biogenesis of 60S ribosomal subunits in budding yeast (Saccharomyces cerevisiae). Here, we examined whether the fission yeast (Schizosaccharomyces pombe) homologue of Rrs1 also plays a role in ribosome biogenesis. To this end, we constructed two temperature-sensitive fission yeast strains, rrs1-D14/22G and rrs1-L51P, which had amino acid substitutions corresponding to those of the previously characterized budding yeast rrs1-84 (D22/30G) and rrs1-124 (L61P) strains, respectively. The fission yeast mutants exhibited severe defects in growth and 60S ribosomal subunit biogenesis at high temperatures. In addition, expression of the Rrs1 protein of fission yeast suppressed the growth defects of the budding yeast rrs1 mutants at high temperatures. Yeast two-hybrid analyses revealed that the interactions of Rrs1 with the Rfp2 and Ebp2 proteins were conserved in budding and fission yeasts. These results suggest that the essential function of Rrs1 in ribosome biogenesis may be conserved in budding and fission yeasts.

A concept for an automated rail-road intermodal courier service system is proposed. While rail transport suffers a number of difficulties, such as long exchange time, large container size and slow speed, the proposed system aims to solve them using ITS-aided transfer robots and an ICT-based routing system. The system is based on a loosely coupled design by which the flexibility of rail networks can be utilized. We investigated the feasibility of the proposed system in economical, physical and technological aspects and obtained positive results. This system copes with aging society, and future industry needs for automation and just-in-time delivery of small packets.

Polymers consisting of benzo[1,2-b:4,5-b′]dithiophene and thieno[3,4-b]thiophene units (PTB-based polymers), either fully or partially containing 4-fluorophenyl pendants, are synthesized as electron donor materials for inverted-type polymer solar cells (PSCs). The influence of the 4-fluorophenyl pendant content on the thermal and optical properties, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), the hole mobilities, and photovoltaic performances are investigated. As the 4-fluorophenyl pendant content increased, the HOMO and LUMO of the polymers were deepened proportionally and the open-circuit voltages of the PSCs improved. Incorporation of 4-fluorophenyl pendants into the polymers also affected the crystallinity, orientation, and compatibility with [6,6]-phenyl-C61-butyric acid methyl ester in the active layers, leading to nonlinearities in the short-circuit current densities, and fill factors. The incorporation of an appropriate number of 4-fluorophenyl pendants enhanced the power conversion efficiencies of the PSC devices from 2.25 to 3.96% for identical device configurations. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1586–1593

Optically active narrow-bandgap polymers ((R,R)- and (S,S)-PTB5) consisting of alternating n-octyl thieno[3,4-b]thiophene-2-carboxylate and benzo[1,2-b:4,5-b′]dithiophene units bearing optically pure (R)- and (S)-2-ethylhexyl pendants, respectively, were synthesized for the first time. (R,R)- and (S,S)-PTB5 films showed apparent circular dichroism in their absorption regions of the polymer backbone due to the formation of a chirally ordered superstructure induced by the chirality of the branched alkyl pendants. Inverted-type bulk heterojunction polymer solar cells (PSCs) were fabricated using (R,R)- or (S,S)-PTB5 as electron donors and [6,6]-phenyl-C61-butyric acid methyl ester as an electron acceptor. The photovoltaic properties of the PSCs were compared with those of the corresponding PSC containing optically inactive PTB5 bearing racemic 2-ethylhexyl pendants.

An android, i.e., a realistic humanoid robot with human-like capabilities, may induce an uncanny feeling in human observers. The uncanny feeling about an android has two main causes: its appearance and movement. The uncanny feeling about an android increases when its appearance is almost human-like but its movement is not fully natural or comparable to human movement. Even if an android has human-like flexible joints, its slightly jerky movements cause a human observer to detect subtle unnaturalness in them. However, the neural mechanism underlying the detection of unnatural movements remains unclear. We conducted an fMRI experiment to compare the observation of an android and the observation of a human on which the android is modelled, and we found differences in the activation pattern of the brain regions that are responsible for the production of smooth and natural movement. More specifically, we found that the visual observation of the android, compared with that of the human model, caused greater activation in the subthalamic nucleus (STN). When the android’s slightly jerky movements are visually observed, the STN detects their subtle unnaturalness. This finding suggests that the detection of unnatural movements is attributed to an error signal resulting from a mismatch between a visual input and an internal model for smooth movement.

Developing an animal-like highly organized swarm system, which is capable to adapt to environmental changes as well as dynamic situations is undoubtedly complex. A good task allocation method, which can regulate and achieve an efficient labor division among the swarm agents is a crucial element for this kind of systems. In this paper, we propose an extended model of the simple Response Threshold Model using a discretized version of the Attractor Selection paradigm in order to dynamically control the threshold parameter. Simulation experiments are carried out with the purpose of studying the effects of these optimization measures on the performance of a foraging mission. Simulation experiments verified that the resultant optimized model can improve adaptation capabilities of previous systems, making a swarm of robots able to adapt more efficiently to dynamical situations, and therefore increase its survival rate.

Single-phased polycrystalline Mn- and Fe-doped ${\rm Bi}_{4}{\rm Ti}_{3}{\rm O}_{12}$ were fabricated using a solid-state reaction technique, doping with various concentrations of Mn and Fe ions. Substitution mechanism of Mn and Fe ions in ${\rm Bi}_{4}{\rm Ti}_{3}{\rm O}_{12}$ were investigated with X-ray absorption near-edge structure (XANES) measurements and first-principles calculations. The valence states of the Mn and Fe ions are 4+ and 3+, respectively, inferred from the ${\rm L}_{2,3}$ -edge XANES profiles. From the K-edge XANES analysis, it is determined that Mn and Fe ions are substituted at one of the Ti sites, i.e., Ti(2a) or Ti(4e) sites. Our first-principles total electronic energy calculations suggest that Mn ions are likely to substitute at Ti(2a) sites rather than at Ti(4e) sites, whereas the opposite is true for Fe substitution. Taken together, these results give a clear description of the locations and charge states of the Mn and Fe dopants in ${\rm Bi}_{4}{\rm Ti}_{3}{\rm O}_{12}$ .

We investigated the desorption of water from a TiO2 surface under a dry atmosphere by collecting the photoemission yield spectra with an open counter. For this purpose, a new attachment for the photoemission yield measurement was prepared. This apparatus is capable of detecting, in the open air, low-energy electrons excited by photons under dried atmospheres; the dew point is below -35°C. A significant change in the photoemission yield spectra due to exposure to a dry atmosphere was observed. To gain a better understanding of these results, observations of the change in the photoemission yield spectra caused by the thermal desorption of adsorbed water were also carried out. The results are consistent with those obtained by exposure to a dry atmosphere. Based on the relationship between the photoemission yield and the thickness of the water layer, the time dependence of the change in the thickness was explained by the second-order reaction rate equation.

A series of dithieno[3,2-b:2′,3′-d]silole-based π-conjugated copolymers containing thieno[3,4-c]pyrrole-4,6-dione or thieno[3,4-b]thiophene units bearing 4-substituted phenyl pendants were synthesized and their thermal stability, optical properties and frontier orbital energy levels were systematically investigated. The introduction of electron-withdrawing substituents on the phenyl rings lowered their frontier orbital energy levels without deteriorating their thermal and optical properties. By replacing an electron-donating methoxy group with an electron-withdrawing trifluoromethyl group, both the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital energy levels of the polymers were deepened by more than 0.3 eV. A relatively linear relationship was observed between the HOMO energy levels and the Hammett substituent constants.

We discuss here geometric structures of condensed matters by means of a fundamental topological method. Any geometric pattern can be universally represented by a decomposition space of a topological space consisting of the infinite product space of 0 and 1, in which a partition with a specific topological structure determines a character of each geometric structure.

Controlling human-like robots with musculoskeletal structure has been a challenging problem in engineering. In biological studies, motor synergy hypothesis has been proposed as a solution in order to control high degree-of-freedom and complex human body. In this paper, we focus on exploring the applicability of motor synergies in generating goal-directed movements by optimal control in a human-like robotic arm. We focus on three problems: 1) Can motor synergies facilitate the solving of optimal control problem? 2) What properties should motor synergies have in order to achieve tasks? 3) How should motor synergies be utilized better? For the first problem we show that goal-directed movements can be achieved by utilizing motor synergies which have properties of achieving the goals. For the second problem, we testify motor synergies which have different properties and discover that energy efficiency is an important aspect in motor synergies which can also be utilized to achieve goal-directed movements. This discovery also implies that we can obtain motor synergies by other ways rather than from goal-directed optimal control signals. For the third problem, we show that the control complexity can be further reduced by utilizing a subset of motor synergies which are effective to achieve goals.

A flow chemiluminescence (CL) method combined with a liquid–liquid extraction technique is proposed for the indirect determination of antimony in aqueous samples using rhodamine B (RB). In the liquid–liquid extraction process, the antimony(V) chloro-complex anion, [SbCl6]−, was extracted from an aqueous acidic solution into toluene via ion-pair formation with the protonated RBH+ ion. Upon mixing the extract with a reversed micellar reagent solution of cetyltrimethylammonium chloride (CTAC) in 1-hexanol–cyclohexane/water (0.60 mol dm−3 H2SO4) containing cerium(IV), uptake of the ion-pair by CTAC reversed micelles occurred easily, followed by an oxidation reaction of RB with Ce(IV) in the CL process. The CL signal produced was then measured. Using a flow injection system, the detection limits (DL) of 0.25 μmol dm−3 Sb(III) and 0.20 μmol dm−3 Sb(V), and linear calibration graphs with dynamic ranges from the respective DLs to 16 μmol dm−3 for Sb(III) and Sb(V) were obtained under optimized experimental conditions. The proposed method was successfully applied to a mixture of Sb(III) and Sb(V), where total antimony, Sb(III) + Sb(V), was measured using ceric sulfate as an oxidant to oxidize Sb(III) to Sb(V) prior to extraction, Sb(V) was determined directly without the use of an oxidant, and Sb(III) was calculated by difference., This work was partially supported by a Grant-in-Aid for Scientific Research, No. 23550097, from the Ministry of Education, Science, Sports, and Culture, Japan.

Soft X-ray exposure effects on CH 3 NH 3 PbI 3 perovskite in a patterned device sample with a similar structure to solar cells, a promising candidate for X-ray detectors, have been investigated with an X-ray Photoelectron Spectroscopy (XPS) time-dependent measurement method. Our experimental analyses demonstrate compositional change from CH 3 NH 3 PbI 3 to PbI 2 due to evaporation of methylammonium iodide.

Polycrystalline Fe-doped BaMgSiO4 is synthesized by the conventional solid state reaction method, which shows strong photochromism. Photochromic property of the synthesized specimens is investigated by measuring the diffuse reflectance spectrum. Local environment of doped Fe ions in BaMgSiO4 has been studied by the analysis of the X-ray absorption near-edge structure (XANES) spectrum with the aid of the first-principles calculations.

The valence band electronic structures of Mn- and/or Fe-doped In 2 O 3 , i.e., In 2 O 3 :Mn, In 2 O 3 :Fe, and In 2 O 3 :(Mn, Fe), are investigated by photoemission yield measurements. Significant changes are observed in the threshold energy of photoemission, depending on the doped magnetic ions, which indicates that an additional occupied band appears above the top of the valence band of In 2 O 3 owing to doping with Mn and/or Fe ions. It is confirmed that the order of the threshold energies of photoemission, E PET , is E PET (In 2 O 3 :Mn) E PET (In 2 O 3 :(Mn, Fe)) E PET (In 2 O 3 :Fe) E PET (In 2 O 3 ). To gain a better understanding of these results, first-principles molecular orbital calculations are also carried out, which successfully explain the observed changes in the photoemission threshold energies.

Accepted: 2012-03-28, 資料番号: SA1004250000

We evaluated exposed-radiation doses on dual-source cardiac computed tomography (CT) examinations with prospective electrocardiogram (ECG)-gated fast dual spiral scans. After placing dosimeters at locations corresponding to each of the thoracic organs, prospective ECG-gated fast dual spirals and retrospective ECG-gated dual spiral scans were performed to measure the absorbed dose of each organ. In the prospective ECG-gated fast dual spiral scans, the average absorbed doses were 5.03 mGy for the breast, 9.96 mGy for the heart, 6.60 mGy for the lung, 6.48 mGy for the bone marrow, 9.73 mGy for the thymus, and 4.58 mGy for the skin. These values were about 5% of the absorbed doses for the retrospective ECG-gated dual spiral scan. However, the absorbed dose differed greatly at each scan, especially in the external organs such as the breast. For effective and safe use of the prospective ECG-gated fast dual spiral scan, it is necessary to understand these characteristics sufficiently.

The detailed valence states of Mn and Fe ions in room-temperature ferromagnetic In2O3 doped with Mn and Fe ions were investigated by the near-edge X-ray absorption fine structure (NEXAFS) measurements. It was confirmed that Mn2+ and Mn3+ coexist in In2O3. In addition to these two magnetic ions, Sn4+ was incorporated to control the charge states of doped Mn and/or Fe ions, which makes the Mn2+/Mn3+ ratio larger with an increase in the doped- Sn4+ concentration. It was found that the magnetic susceptibility decreased with an increase in Mn2+ because of the Sn4+-doping, which indicated that the coexistence of Mn2+ and Mn3+ is mandatory for room-temperature ferromagnetism in Mn- and Fe-codoped In2O3.

Summary Organ doses are useful for estimating radiation doses to patients. However, it is impossible to determine specific organ doses for each patient. The aim of this study was to examine the relationship between specific organ doses and volumetric CT dose indices (CTDIvols) in multidetector CT studies to estimate specific organ doses in each patient. Radiophotoluminescent glass dosimeters were placed at locations corresponding to specific organs of an anthropomorphic phantom. Thereafter, the phantoms were examined with respect to various imaging ranges and protocols, including cranial, thoracic and abdominal acquisitions using a 64-section multidetector CT. Concurrently, we recorded the mean CTDIvol for each acquisition range. In the cranial acquisition, the displayed mean CTDIvol was 69.0 mGy, and the absorbed doses for brain and intra-ocular lenses were 57.2 ± 2.6 and 57.1 ± 3.0 mGy, respectively. In the thoracic acquisition, the displayed mean CTDIvol was 16.3 mGy, and the absorbed doses for breast and lung were 19.1 ± 6.4 and 31.7 ± 2.2 mGy, respectively. In the abdominal acquisition, the displayed mean CTDIvol was 21.6 mGy, and the absorbed doses for stomach and colon were 28.2 ± 6.1 and 28.0 ± 8.6 mGy, respectively. The displayed mean CTDIvols overestimated the specific organ doses in the cranial acquisition and underestimated them in the thoracic and abdominal acquisitions. However, the approximate specific organ doses may be estimated by multiplying the displayed mean CTDIvols with a conversion factor for each organ.

Background Though appropriate image acquisition parameters allow an effective dose below 1 mSv for CT coronary angiography (CTCA) performed with the latest dual-source CT scanners, a single-source 64-detector CT procedure results in a significant radiation dose due to its technical limitations. Therefore, estimating the radiation doses absorbed by an organ during 64-detector CTCA is important. Purpose To estimate the radiation doses absorbed by organs located in the chest region during 64-detector CTCA using different acquisition techniques and heart rates. Material and Methods Absorbed doses for breast, heart, lung, red bone marrow, thymus, and skin were evaluated using an anthropomorphic phantom and radiophotoluminescence glass dosimeters (RPLDs). Electrocardiogram (ECG)-gated helical and ECG-triggered non-helical acquisitions were performed by applying a simulated heart rate of 60 beats per minute (bpm) and ECG-gated helical acquisitions using ECG modulation (ECGM) of the tube current were performed by applying simulated heart rates of 40, 60, and 90 bpm after placing RPLDs on the anatomic location of each organ. The absorbed dose for each organ was calculated by multiplying the calibrated mean dose values of RPLDs with the mass energy coefficient ratio. Results For all acquisitions, the highest absorbed dose was observed for the heart. When the helical and non-helical acquisitions were performed by applying a simulated heart rate of 60 bpm, the absorbed doses for heart were 215.5, 202.2, and 66.8 mGy for helical, helical with ECGM, and non-helical acquisitions, respectively. When the helical acquisitions using ECGM were performed by applying simulated heart rates of 40, 60, and 90 bpm, the absorbed doses for heart were 178.6, 139.1, and 159.3 mGy, respectively. Conclusion ECG-triggered non-helical acquisition is recommended to reduce the radiation dose. Also, controlling the patients’ heart rate appropriately during ECG-gated helical acquisition with ECGM is crucial.

Rhythm is an essential element of music, but how we acquire it has not been investigated in detail. Some argue that learners acquire rhythms mentally, and others argue that body movements are involved. This study, therefore, investigated how body movements affect the rhythmic performances of learners in the course of rhythm acquisition. We used accelerometers to measure the arm and lumbar accelerations of 17 participants who took samba lessons regularly for 10 months. Detailed analyses revealed that all learners who learnt to play the shaker to a samba rhythm exhibited samba-like rhythmic patterns in both lumbar and arm movements. This indicates that the coordination contributing to the lumber movement has something to do with the acquisition of samba rhythm, and this is consistent with the argument that body movements are involved in acquiring rhythms.

In this paper, we introduce a wearable accelerometer array system and propose a method for analysis of human movements. While many studies of sensor networks have aimed at scalability and/or accura...

Zn-doped β-tricalcium phosphate (β-TCP) is synthesized by the solid-state reaction method. The substitution mechanism of Zn ions in β-TCP synthesized here is investigated by carrying out a combination of near-edge X-ray absorption fine structure (NEXAFS) measurements and first-principles calculations. From the results of the present study, the substitution site for Zn ions in β-TCP is successfully determined.

In the direction where the phased array coil used in parallel magnetic resonance imaging (MRI) is perpendicular to the arrangement, sensitivity falls significantly. Moreover, in a 3.0 tesla (3T) abdominal MRI, the quality of the image is reduced by changes in the relaxation time, reinforcement of the magnetic susceptibility effect, etc. In a 3T MRI, which has a high resonant frequency, the signal of the depths (central part) is reduced in the trunk part. SCIC, which is sensitivity correction processing, has inadequate correction processing, such as that edges are emphasized and the central part is corrected. Therefore, we used 3T with a Gaussian distribution. The uneven compensation processing for sensitivity of an abdomen MR image was considered. The correction processing consisted of the following methods. 1) The center of gravity of the domain of the human body in an abdomen MR image was calculated. 2) The correction coefficient map was created from the center of gravity using the Gaussian distribution. 3) The sensitivity correction image was created from the correction coefficient map and the original picture image. Using the Gaussian correction to process the image, the uniformity calculated using the NEMA method was improved significantly compared to the original image of a phantom. In a visual evaluation by radiologists, the uniformity was improved significantly using the Gaussian correction processing. Because of the homogeneous improvement of the abdomen image taken using 3T MRI, the Gaussian correction processing is considered to be a very useful technique.

The general method of measuring the half-value layer (HVL) for X-ray computed tomography (CT) using square aluminum-sheet filters is inconvenient in that the X-ray tube has to be set to stationary mode. To avoid this inconvenience, we investigated a new method using copper-pipe filters that cover the ionization chamber (copper-pipe method). Using this method, the HVL can be measured at the isocenter in the rotation modes of CT. We examined the accuracy and reproducibility of the copper-pipe method compared with those of the general method. The effective energy measured using the copper-pipe method correlated well with the general method (y=1.064x, r=0.987), and its error was 1.81±1.38%. The results indicate that the copper-pipe method enables accurate measurement of the effective energy of X-ray CT and is a convenient method suited to all general X-ray equipment as well as all X-ray CT.

Development of a new electricity generation techniques is one of the most relevant tasks, especially nowadays under conditions of extreme growth in energy consumption. The exothermic heterogeneous electrochemical energy conversion to the electric energy through interaction of the ZrO2 based nanopowder system with atmospheric moisture is one of the ways of electric energy obtaining. The questions of conversion into the electric form of the energy of water molecules adsorption in 3 mol% Y2O3 doped ZrO2 nanopowder systems were investigated using the density functional theory calculations. The density functional theory calculations has been realized as in the Kohn-Sham formulation, where the exchange-correlation potential is approximated by a functional of the electronic density. The electronic density, total energy and band structure calculations are carried out using the all-electron, full potential, linear augmented plane wave method of the electronic density and related approximations, i.e. the local density, the generalized gradient and their hybrid approximations.

Inappropriate patient centering on the gantry changes the size of the localizer radiographs used for CT examinations, influencing the operation of CT automatic tube current modulation because tube current is controlled with information from localizer radiographs. The purpose of this study was to examine the influence of inappropriate patient centering on the gantry isocenter on automatic tube current modulation.An elliptical phantom was scanned with four automatic tube current modulation techniques after acquisition of localizer radiographs in the horizontal and vertical directions with the phantom center shifted from the gantry isocenter in the vertical direction. After scanning, the magnification rate of the frontal localizer radiographs, tube current-time product, and image noise were examined.On phantom studies, the magnification rate of localizer radiographs showed a linear relation to the vertical deviation of the phantom from the gantry isocenter. From 50 mm above to 50 mm below the gantry isocenter, tube current-time products ranged from 75% to 141% compared with those at the gantry isocenter. In addition, increases and decreases in the amount of image noise related to changes in tube current-time product were confirmed.Inappropriate patient centering causes misoperation of automatic tube current modulation systems, in which tube current is controlled with information from localizer radiographs, and thus causes increases in tube current or image noise.

Rationale and Objectives Chest computed tomographic (CT) scans are the most effective examinations for detecting lung cancer at an early stage. In chest CT examinations, it is important to consider the reduction of radiation dose, particularly to the mammary gland. The objective of this study was to assess breast doses and effective doses on chest CT examinations between three-dimensional and z-axis automatic tube current modulation (ATCM) techniques. Materials and Methods Absorbed dose to the breast, lung, mediastinum, and skin was evaluated with an anthropomorphic phantom and radiophotoluminescence glass dosimeters using two different CT scanners. The dosimeters were placed inside and outside the phantom. The phantom was scanned using three-dimensional and z-axis ATCM techniques after scanning localizer radiographs from the horizontal and vertical directions. After scanning, each organ dose was calculated. Moreover, the dose-length product recorded in the dose reports was examined, and each effective dose was calculated. Results Compared with z-axis ATCM, three-dimensional ATCM reduced breast dose by 0.7% to 18.6% and effective dose by 4.9% to 10.2%. In particular, three-dimensional ATCM reduced frontal breast dose. For other organs, three-dimensional ATCM reduced absorbed doses by 3.4% to 13.6% compared to z-axis ATCM. Conclusion Three-dimensional ATCM can reduce absorbed doses to the breast and other organs, in addition to reducing effective dose, compared to z-axis ATCM.

The effectiveness of a positioning doll for radiography training (XPD) and acquiring the techniques of radiography was evaluated through performing radiography practice for the students in our school of radiological technologists and a questionnaire for radiological technologists. We made a ranking test composed of a five-grade evaluation system of the 39 students for the techniques of radiography before and after the practice, and questionnaires about the XPD were given to the same students after the practice. The questionnaires about affinities between human bodies and the XPD and effectiveness of the XPD for the education of students were also carried out in six radiological technologists to examine the effectiveness of the practice of radiography by using the XPD. The rankings of the students after the practice were significantly higher than those before the practice (p

Phonon states of Ag doped potassium halides, KX:Ag + (X = Cl, Br and I), are computed by a first principles lattice dynamic method using 64-atoms supercells. Results are compared to experimental data in literature. Phonon density of states of host KCl and KI crystals satisfactorily agree to the experimental inelastic neutron scattering data. Experimental frequencies of the impurity-induced infra-red (IR) and Raman active modes in the low frequency region are reasonably well reproduced because the vibrations are localized within the first nearest neighbour anions of the Ag + -ion. On the other hand, limitations of present calculations to reproduce the high frequency impurity-induced modes are pointed out. They are less localized to the Ag + -ion.

An experiment was conducted to study the skill of clay kneading in pottery. This task usually requires a few years to master and is therefore well suited to study the long-term development of a complex motor skill. Participants' kneading movements were measured in 3D using a motion capture device and phase relations among coordinates and joint angles were analyzed in terms of the mutual phase relative to a reference point using the Hilbert transform. While a certain degree of periodicity was observed in all 10 participants, the behavior of the experts was characterized by a significant delay for the right elbow (i.e., the pushing arm) and the fore-aft position of the upper torso and only brief delays for the other parts, which all tended to synchronize with the reference. These findings are consistent with our notion of "differentiation within coordination", according to which skill learning proceeds in a hierarchical manner in that coordination among limb movements is established first, followed by modulations of specific limb movements within the established coordination. Although this feature of expert behavior was also apparent in our previous studies of clay kneading and samba shaking and dancing, the numbers of participants in those studies were not sufficient to draw firm conclusions. Since the present study involved more participants and a superior method of analysis, the present evidence for the principle of differentiation within coordination is more conclusive.

UNLABELLED In this study, we evaluated clinical images to determine appropriate settings for slice thickness in screening examinations for hepatocellular carcinoma and metastatic liver cancer, which are frequently performed in abdominal CT. The clinical images of 15 cases screened for hepatocellular carcinoma and 15 cases screened for metastatic liver cancer were evaluated. The evaluation was visually performed by three abdominal radiologists, and the sensitivity and specificity of each slice thickness were calculated. RESULTS differences in sensitivity and specificity were not found between slice thicknesses of 2.5 mm and 5.0 mm; however, sensitivity and specificity were low, and confidence was also low at a 10.0 mm slice thickness. Furthermore, when a 5.0 mm slice thickness was adopted, it was shown that radiation dose in limited parts could be reduced greatly to a noise level that compared equally with a study in which a 2.5 mm slice thickness was adopted in another evaluation. Therefore, the objective could be achieved by using a slice thickness of about 5.0 mm in multidetector-row CT examinations for the screening of liver cancer, while controlling patient dose to a minimum.