Search results for: Yasuo Hasegawa

Authors: Ueda Honoka, Yasuo Hasegawa, Fumihiro Nishimura, Jae-Ho Kim, Susumu Yonezawa

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Aqueous peroxotitanium acid solution prepared from the TiO₂ fluorinated by F₂ gas was used for the TiO₂ coating on glass fibrous filters in this study. The coating of TiO₂ on the surface of glass fibers was carried out at 120℃ and for 15 min ~ 24 h with aqueous peroxotitanium acid solution using a hydrothermal synthesis autoclave reactor. The morphology TiO₂ coating layer was largely dependent on the reaction time, as shown in the results of scanning electron microscopy and energy dispersive X-ray spectroscopy. Increasing the reaction times, the TiO₂ layer on the glass expanded uniformly. Moreover, the surface fluorination of glass fibers can promote the formation of the TiO₂ layer on the surface. The photocatalytic activity of prepared titania-coated glass fibrous filters was investigated by both the degradation test of methylene blue (MB) and the decomposition test of gaseous acetaldehyde. The MB decomposition ratio with fluorinated samples was about 95% for 30 min of UV irradiation time, and it was much higher than that (70%) with the untreated thing. The decomposition ratio (50%) of gaseous acetaldehyde with fluorinated samples was also higher than that (30%) with the untreated thing. Consequently, photocatalytic activity is enhanced by surface fluorination.

Keywords: aqueous peroxotitanium acid solution, titania-coated glass fibrous filters, photocatalytic activity, surface fluorination

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Authors: Eiko Takaoka, Yoshiyuki Fukushima, Koichiro Hirose, Tadashi Hasegawa

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Although all high school students in Japan are required to learn informatics, many of them do not learn this topic sufficiently. In response to this situation, we propose a support package for high school informatics classes. To examine what students learned and if they sufficiently understood the context of the lessons, a questionnaire survey was distributed to 186 students. We analyzed the results of the questionnaire and determined the weakest units, which were “basic computer configuration” and “memory and secondary storage”. We then developed a package for teaching these units. We propose that our package be applied in high school classrooms.

Keywords: computer science unplugged, computer science outreach, high school curriculum, experimental evaluation

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Authors: Ayako Hasegawa, Ken Ubukata

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The purpose of this study is to investigate whether corrective feedback has any significant effect on Japanese low-intermediate EFL learners’ performance on a specific set of linguistic features. The subjects are Japanese college students majoring in English. They have studied English for about 7 years, but their inter-language seems to fossilize because non-target like errors is frequently observed in traditional deductive teacher-fronted approach. It has been reported that corrective feedback plays an important role in diminishing or overcoming inter-language fossilization and achieving TL competency. Therefore, it was examined how the corrective feedback (the focus of this study was metalinguistic feedback) and self-correction raised the students’ awareness and helped them notice the gaps between their inter-language and the TL.

Keywords: written corrective feedback, fossilized error, grammar teaching, language teaching

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Authors: Sina Ranjbar, Masakiyo Tsunoda, Mikihiko Oogane, Yasuo Ando

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We systematically investigated the exchange anisotropy for ferromagnetic Co70Fe30 and antiferromagnetic PtMn bilayer films. We focused on the relevance between the exchange bias and the composition of the Ptₓ Mn₁₋ₓ (14 < x < 22 and 45 < x < 56 at %) films, and we successfully optimized the composition. The crystal structure of the Ptₓ Mn₁₋ₓ films was FCC for 14 < x < 22 at % and FCT for 45 < x < 56 at % after annealing at 370 ◦C for 6 hours. The unidirectional anisotropy constant (Jₖ) for fcc-Pt₁₅Mn₈₅ (20 nm) and fct-Pt₄₈Mn₅₂ (20 nm) prepared under optimum conditions in composition were 0.16 and 0.20 erg/cm², respectively. Both Pt₁₅Mn₈₅ and Pt₄₈Mn₅₂ films showed a larger unidirectional anisotropy constant (Jₖ) than in other reports. They also showed a flatter surface than that of other antiferromagnetic materials. The obtained PtMn films with a large exchange anisotropy and slight roughness are useful as an antiferromagnetic layer in spintronic applications.

Keywords: antiferromagnetic material, PtMn thin film, exchange anisotropy, composition dependence

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Authors: Seigo Matsuno, Yasuo Uchida, Shozo Tokinaga

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This paper proposes and empirically tests a model of the relationships between green supply chain management (GSCM) activities and corporate performance. From the literature review, we identified five constructs, namely, environmental commitment, supplier collaboration, supplier assessment, information sharing among suppliers, and business process improvement. These explanatory variables are used to form a structural model explaining the environmental and economic performance. The model was analyzed using the data from a survey of a sample of manufacturing firms in Japan. The results suggest that the degree of supplier collaboration has an influence on the environmental performance directly. While, the impact of supplier assessment on the environmental performance is mediated by the information sharing and/or business process improvement. And the environmental performance has a positive relationship on the economic performance. Academic and managerial implications of our findings are discussed.

Keywords: corporate performance, empirical study, green supply chain management, path modeling

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Authors: Luan Trong Nguyen, M. Azizur Rahman, Yusuke Tamenori, Toshihiro Yoshimura, Nozomu Iwasaki, Hiroshi Hasegawa

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This study investigated the distribution of magnesium (Mg), phosphorus (P), sulfur (S) and strontium (Sr) using micro X-ray fluorescence (µ-XRF) along the annual growth rings in the skeleton of Japanese red coral Paracorallium japonicum. The Mg, P and S distribution in µ-XRF mapping images correspond to the dark and light bands along the annual growth rings observed in microscopic images of the coral skeleton. The µ-XRF mapping data showed a positive correlation (r = 0.6) between P and S distribution in the coral skeleton. A contrasting distribution pattern of S and Mg along the axial skeleton of P. japonicum indicates a weak negative correlation (r = -0.2) between these two trace elements. The distribution pattern of S, P and Mg reveals linkage between their distributions and the formation of dark/light bands along the annual growth rings in the axial skeleton of P. japonicum. Sulfur and P were distributed in the organic matrix rich dark bands, while Mg was distributed in the light bands of the annual growth rings.

Keywords: µ-XRF, trace element, precious coral, Paracorallium japonicum

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Authors: Makoto Hasegawa, Seika Tokumitsu

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Spectra of light beams emitted from white-color LED torches are different from those of conventional electric torches. In order to confirm if white-color LED torches can be used as light sources for popular sunset color demonstrations in spite of such differences, spectra of travelled light beams and scattered light beams with each of a white-color LED torch (composed of a blue LED and yellow-color fluorescent material) and a conventional electric torch as a light source were measured and compared with each other in a 50 cm-long water tank for sunset color demonstration experiments. Suspension liquid was prepared from acryl-emulsion and tap-water in the water tank, and light beams from the white-color LED torch or the conventional electric torch were allowed to travel in this suspension liquid. Sunset-like color was actually observed when the white-color LED torch was used as the light source in sunset color demonstrations. However, the observed colors when viewed with naked eye look slightly different from those obtainable with the conventional electric torch. At the same time, with the white-color LED, changes in colors in short to middle wavelength regions were recognized with careful observations. From those results, white-color LED torches are confirmed to be applicable as light sources in sunset color demonstrations, although certain attentions have to be paid. Further advanced classes will be successfully performed with white-color LED torches as light sources.

Keywords: blue sky demonstration, sunset color demonstration, white LED torch, physics education

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Authors: Shohei Maruyama, Yasuo Matsuyama, Sachiyo Aburatani

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The development of the method to annotate unknown gene functions is an important task in bioinformatics. One of the approaches for the annotation is The identification of the metabolic pathway that genes are involved in. Gene expression data have been utilized for the identification, since gene expression data reflect various intracellular phenomena. However, it has been difficult to estimate the gene function with high accuracy. It is considered that the low accuracy of the estimation is caused by the difficulty of accurately measuring a gene expression. Even though they are measured under the same condition, the gene expressions will vary usually. In this study, we proposed a feature extraction method focusing on the variability of gene expressions to estimate the genes' metabolic pathway accurately. First, we estimated the distribution of each gene expression from replicate data. Next, we calculated the similarity between all gene pairs by KL divergence, which is a method for calculating the similarity between distributions. Finally, we utilized the similarity vectors as feature vectors and trained the multiclass SVM for identifying the genes' metabolic pathway. To evaluate our developed method, we applied the method to budding yeast and trained the multiclass SVM for identifying the seven metabolic pathways. As a result, the accuracy that calculated by our developed method was higher than the one that calculated from the raw gene expression data. Thus, our developed method combined with KL divergence is useful for identifying the genes' metabolic pathway.

Keywords: metabolic pathways, gene expression data, microarray, Kullback–Leibler divergence, KL divergence, support vector machines, SVM, machine learning

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Authors: Xiyao Shan, Pavlos Evangelidis, Adam Kositsky, Naoki Ikeda, Yasuo Kawakami

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The human triceps surae (two bi-articular gastrocnemii and one mono-articular soleus) have aponeuroses in the posterior and anterior aspects of each muscle, where the anterior aponeuroses of the gastrocnemii adjoin the posterior aponeurosis of the soleus, possibly contributing to the intermuscular force transmission between gastrocnemii and soleus. Since the mechanical behavior of these aponeuroses at different knee- and ankle-joint positions remains unclear, the purpose of this study was to clarify this through observations of the localized changes in passive stiffness of the posterior aponeuroses, muscle belly and adjoining aponeuroses of the medial gastrocnemius (MG) induced by different knee and ankle angles. Eleven healthy young males (25 ± 2 yr, 176.7 ± 4.7 cm, 71.1 ± 11.1 kg) participated in this study. Each subject took either a prone position on an isokinetic dynamometer while the knee joint was fully extended (K180) or a kneeling position while the knee joint was 90° flexed (K90), in a randomized and counterbalanced order. The ankle joint was then passively moved through a 50° range of motion (ROM) by the dynamometer from 30° of plantar flexion (PF) to 20° of dorsiflexion (DF) at 2°/s and the ultrasound shear-wave velocity was measured to obtain shear moduli of the posterior aponeurosis, MG belly, and adjoining aponeuroses. The main findings were: 1) shear modulus in K180 was significantly higher (p < 0.05) than K90 for the posterior aponeurosis (across all ankle angles, 10.2 ± 5.7 kPa-59.4 ± 28.7 kPa vs. 5.4 ± 2.2 kPa-11.6 ± 4.1 kPa), MG belly (from PF10° to DF20°, 9.7 ± 2.2 kPa-53.6 ± 18.6 kPa vs. 8.0 ± 2.7 kPa-9.5 ± 3.7 kPa), and adjoining aponeuroses (across all ankle angles, 17.3 ± 7.8 kPa-80 ± 25.7 kPa vs. 12.2 ± 4.5 kPa-52.4 ± 23.0 kPa); 2) shear modulus of the posterior aponeuroses significantly increased (p < 0.05) from PF10° to PF20° in K180, while shear modulus of MG belly significantly increased (p < 0.05) from 0° to PF20° only in K180 and shear modulus of adjoining aponeuroses significantly increased (p < 0.05) across the whole ROM of ankle both in K180 and K90. These results suggest that different knee-joint positions can affect not only the bi-articular gastrocnemius but also influence the mechanical behavior of aponeuroses. In addition, compared to the gradual stiffening of the adjoining aponeuroses across the whole ROM of ankle, the posterior aponeurosis became slack in the plantar flexed positions and then was stiffened gradually as the knee was fully extended. This suggests distinct stiffening for the posterior and adjoining aponeuroses which is joint position-dependent.

Keywords: aponeurosis, plantar flexion and dorsiflexion, shear modulus, shear wave elastography

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Authors: Ami Okabe, Daisuke Gondo, Akira Ogawa, Yasuhisa Hasegawa, Koichi Sato, Sadao Araki, Hideki Yamamoto

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Membrane separation draws attention as the energy-saving technology. Pervaporation (PV) uses hydrophobic ceramic membranes to separate organic compounds from industrial wastewaters. PV makes it possible to separate organic compounds from azeotropic mixtures and from aqueous solutions. For the PV separation of low concentrations of organics from aqueous solutions, hydrophobic ceramic membranes are expected to have high separation performance compared with that of conventional hydrophilic membranes. Membrane separation performance is evaluated based on the pervaporation separation index (PSI), which depends on both the separation factor and the permeate flux. Ingenuity is required to increase the PSI such that the permeate flux increases without reducing the separation factor or to increase the separation factor without reducing the flux. A thin separation layer without defects and pinholes is required. In addition, it is known that the flux can be increased without reducing the separation factor by reducing the diffusion resistance of the membrane support. In a previous study, we prepared hydrophobic silica membranes by a molecular templating sol−gel method using cetyltrimethylammonium bromide (CTAB) to form pores suitable for permitting the passage of organic compounds through the membrane. We separated low-concentration organics from aqueous solutions by PV using these membranes. In the present study, hydrophobic silica membranes were prepared on a porous alumina hollow fiber support that is thinner than the previously used alumina support. Ethyl acetate (EA) is used in large industrial quantities, so it was selected as the organic substance to be separated. Hydrophobic silica membranes were prepared by dip-coating porous alumina supports with a -alumina interlayer into a silica sol containing CTAB and vinyltrimethoxysilane (VTMS) as the silica precursor. Membrane thickness increases with the lifting speed of the sol in the dip-coating process. Different thicknesses of the γ-alumina layer were prepared by dip-coating the support into a boehmite sol at different lifting speeds (0.5, 1, 3, and 5 mm s-1). Silica layers were subsequently formed by dip-coating using an immersion time of 60 s and lifting speed of 1 mm s-1. PV measurements of the EA (5 wt.%)/water system were carried out using VTMS hydrophobic silica membranes prepared on -alumina layers of different thicknesses. Water and EA flux showed substantially constant value despite of the change of the lifting speed to form the γ-alumina interlayer. All prepared hydrophobic silica membranes showed the higher PSI compared with the hydrophobic membranes using the previous alumina support of hollow fiber.

Keywords: membrane separation, pervaporation, hydrophobic, silica

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