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ABSTRACT To develop a microscale processing technique for aromatic polyimides (APIs) in supercritical carbon dioxide (scCO2), the relationships between the polymerization condition, the phase behavior during polymerization and the molecular weight of polyamic acid (PAA)-an intermediate in the production of polyimides-were investigated in scCO2 at 50°C. 4,4′-Diaminodiphenyl ether (ODA) and pyromellitic dianhydride (PMDA) were used as monomers of aromatic diamine and tetracarboxylic dianhydride, respectively, and 19 mol % of N,N-Dimethylformamide (DMF) was added to scCO2 as a cosolvent. The cloudy phase appeared immediately when ODA and PMDA were mixed under any experimental conditions. However, the appearances of the phase behaviors during polymerization differed depending on the polymerization pressure and the initial monomer concentration. The number average molecular weight of PAA increased as the monomer concentration was increased in scCO2, as was the case with polymerization in pure DMF at atmospheric pressure, despite differences in the phase behavior. On the other hand, the weight average molecular weight of PAA depended on the phase behaviors during polymerization along with the monomer concentration. Moreover, API obtained from the PAA synthesized in scCO2 was analyzed using a Fourier transform infrared spectrophotometer and thermogravimetric analyzer, and the results were compared with those of APIs obtained by the solution polymerization. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39878. [ABSTRACT FROM AUTHOR]

In hard disk drives, it is important to enlarge the control bandwidth in order to shorten the track pitch for larger data capacity. However, it is difficult for the H∞ control method to increase the control bandwidth if the mechanical resonance modes have uncertainty. This is because the robustness of the H∞ control method is assured by the small-gain theorem for additive or multiplicative perturbation and the control bandwidth is limited by the uncertainty. In this study, we propose an H∞ control method for high-bandwidth design by introducing a new uncertainty model with a feedforward and a feedback path in order to reduce the conservatism of robust design. The effectiveness is shown by numerical simulations. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(4): 54–62, 2010; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21025 [ABSTRACT FROM AUTHOR]

The purpose of this paper is to clarify the common and different views concerning role models respected by university students in Japan, Korea and China, based on the survey of questionnaires. This paper reports the analysis of one question regarding the respected role models, "Write the names of three people you respect in the order that you respect." The results were compared among the countries and derived some interesting tendencies. Japanese students respected "present Japanese (e.g., Ichiro)," while Korean and Chinese students respected "historical people (e.g., Lee, Sun-Shin)." From the viewpoint of Confucianism, many different factors were found and some suggestions were described based on the detailed analysis. [ABSTRACT FROM AUTHOR]

Background: Choroidal osteoma is a rare intraocular tumor, composed of mature bone tissue. We performed high-penetration optical coherence tomography (HP-OCT) on a patient with choroidal osteoma with serous retinal detachment(SRD)., Case: A 49-year-old woman complained of visual loss OD. Best corrected visual acuity OD was 0.4. The right eye showed a yellowish white subfoveal lesion of 3 disc diameters in size. As computed tomography of the tumor showed choroidal calcification, the diagnosis of choroidal osteoma was made. HP-OCT demonstrated the structure of the tumor clearly, but normal choroidal vessels were not depicted. In addition, HP-OCT showed strong signals in the lamina choroidocapillaris, and no choroidal vessels were found in the parafoveal area of the left eye., Conclusion: A case of choroidal osteoma is presented. HP-OCT can detect structural changes in the choroidal lesions at an early stage of the disease.