Effect of the Annealing Temperature of P(VDF/TrFE) Thin Films on their Ferroelectric Properties

Yoshiki Yachi,Takeshi Yoshimura,Norifumi Fujimura 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.7

The effect of annealing temperature on the micro and the crystal structures and the ferroelectric properties of poly(vinylidene fluoride/trifluoro ethylene)(P(VDF/TrFE)) thin films was investigated. The X-ray diffraction results indicated that the crystallization of the film was enhanced at an annealing temperature above 100 ℃. On the other hand, the remnant polarization was increased by annealing at temperatures between 130 and 140 ℃. Therefore, the ferroelectric properties of the P(VDF/TrFE) films were formed to be improved by annealing at temperatures above Tc (123 ℃). The surface morphology and the piezoelectric responses were observed by scanning probe microscopy. The results indicated that small primary grains of P(VDF/TrFE) grew up to large secondary grains with increasing annealing temperature and that some of the small primary grains had large piezoelectric responses.

Distribution of Radionuclides in the Soil Environment and their Transfer to Vegetation following the Fukushima Nuclear Accident

Yasuyuki Muramatsu,Takeshi Ohno,Kazumasa Oda,Midori Sugiyama,Tomoyuki Kobayash,Mamoru Satou,Mutsuto Satou,Shigeto Fujimura,Hiroyuki Matsuzaki 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Direct Piezoelectricity of PZT Films and Application to Vibration Energy Harvesting

Hiroki Miyabuchi,Takeshi Yoshimura,Norifumi Fujimura,Shuichi Murakami 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.31

Direct piezoelectric effect of ferroelectric thin films was investigated to discuss the application of ferroelectric films to vibration energy harvesting. From the model of the piezoelectric vibration energy harvester, it was found that the figure of merit (FOM) is proportional to the square of the effective transverse piezoelectric coefficient e_(31,f). The e_(31,f) coefficient of Pb(Zr,Ti)O_3 films were measured by substrate bending method. The e_(31,f) coefficient of the 1-μm and 3-μm -thick PZT films are -6.1 C/m^2 and -9.1 C/m^2 at a compressive strain of 6 × 10^(-5), respectively Furthermore, it was found that the e_(31,f) coefficient increases with increasing the strain, which is favorable for the vibration energy harvesting.

Saturated and Pinched Ferroelectric Hysteresis Loops in BiFeO3 Ceramics

Jin Hong Choi,Takeshi Yoshimura,Norifumi Fujimura,천채일 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.74 No.3

BiFeO3 (BFO) ceramics were prepared by conventional solid-state reaction method without quenching. The eect of the sintering condition on the phase evolution and the ferroelectric proper- ties of these BFO ceramics were investigated. A pinched polarization - electric eld (P-E) hysteresis loop was observed in the sample sintered at high temperature for a short period (820 C for 1 hour) because the domain wall motion is restricted by a large number of ionic defects such as oxygen vacancies. The BFO sample sintered at low temperature for a long period (760 C for 6 hours) displayed a well-saturated P-E hysteresis loop due to its low ionic defect density.

Electronic Transport Property of a YbMnO_3/ZnO Heterostructure

Hiroaki Yamada,Tadahiro Fukushima,Takeshi Yoshimura,Norifumi Fujimura 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.4

The electronic transport property of a YbMnO_3/ZnO heterostructure was investigated. Since ZnO is a polar semiconductor, which has a spontaneous polarization, the spontaneous polarization of YbMnO3 can be expected to affect the carrier transport of the ZnO layer and to interact with that of ZnO. To investigate the effect of the spontaneous polarization of YbMnO_3, we characterized the temperature dependences of the conduction properties of the YbMnO_3/ZnO heterostructure by using Hall-effect measurement and analyzed them by using various scattering effects including polar optical phonon scattering, acoustic phonon scattering through the deformation potential and the piezoelectric potential, ionized impurity scattering and grain boundary scattering. The analysis revealed that the predominant scattering mechanism was changed from grain boundary scattering to ionized impurity scattering by the deposition of YbMnO_3. The change in the scattering mechanism is attributed to a partly depletion of ZnO induced by the spontaneous polarization of YbMnO_3.

A randomized double-blind placebo-controlled trial on the effect of magnesium oxide in patients with chronic constipation

Sumire Mori,Toshihiko Tomita,Kazuki Fujimura,Haruki Asano,Tomohiro Ogawa,Takahisa Yamasaki,Takashi Kondo,Tomoaki Kono,Katsuyuki Tozawa,Tadayuki Oshima,Hirokazu Fukui,Takeshi Kimura,Jiro Watari,Hiroto 대한소화기 기능성질환∙운동학회 2019 Journal of Neurogastroenterology and Motility (JNM Vol.25 No.4

Background/Aims Magnesium oxide (MgO) has been frequently used as a treatment for chronic constipation (CC) since the 1980s in Japan. The aim of this study is to evaluate its therapeutic effects of MgO in Japanese CC patients. Methods We conducted a randomized, double-blind placebo-controlled study. Thirty-four female patients with mild to moderate constipation were randomly assigned to either placebo (n = 17) or MgO group (n = 17) 0.5 g × 3/day for 28 days. Primary endpoint was overall improvement over the 4-week study period. Secondary endpoints were changes from baseline in spontaneous bowel movement (SBM), response rates of complete spontaneous bowel movement (CSBM), stool form, colonic transit time (CTT), abdominal symptom, and quality of life. Results One patient failed to complete the medication regimen and was omitted from analysis: data from 16 placebo and 17 MgO patients were analyzed. The primary endpoint was met by 25.0% of placebo vs 70.6% of MgO group (P = 0.015). MgO significantly improved SBM changes compared to placebo (P = 0.002). However, MgO did not significantly improved response rates of CSBM compared to placebo (P = 0.76). In addition, MgO significantly improved Bristol stool form scale changes (P < 0.001) and significantly improved CTT compared to the placebo group (P < 0.001). MgO significantly improved the Japanese version of the patient assessment of constipation quality of life (P = 0.003). Conclusion Our placebo-controlled study demonstrated that MgO was effective treatment for improving defecation status and shortened CTT in Japanese CC patients with mild to moderate symptoms. Background/Aims Magnesium oxide (MgO) has been frequently used as a treatment for chronic constipation (CC) since the 1980s in Japan. The aim of this study is to evaluate its therapeutic effects of MgO in Japanese CC patients. Methods We conducted a randomized, double-blind placebo-controlled study. Thirty-four female patients with mild to moderate constipation were randomly assigned to either placebo (n = 17) or MgO group (n = 17) 0.5 g × 3/day for 28 days. Primary endpoint was overall improvement over the 4-week study period. Secondary endpoints were changes from baseline in spontaneous bowel movement (SBM), response rates of complete spontaneous bowel movement (CSBM), stool form, colonic transit time (CTT), abdominal symptom, and quality of life. Results One patient failed to complete the medication regimen and was omitted from analysis: data from 16 placebo and 17 MgO patients were analyzed. The primary endpoint was met by 25.0% of placebo vs 70.6% of MgO group (P = 0.015). MgO significantly improved SBM changes compared to placebo (P = 0.002). However, MgO did not significantly improved response rates of CSBM compared to placebo (P = 0.76). In addition, MgO significantly improved Bristol stool form scale changes (P < 0.001) and significantly improved CTT compared to the placebo group (P < 0.001). MgO significantly improved the Japanese version of the patient assessment of constipation quality of life (P = 0.003). Conclusion Our placebo-controlled study demonstrated that MgO was effective treatment for improving defecation status and shortened CTT in Japanese CC patients with mild to moderate symptoms.

Features of Fatal Truck Accidents Compared with Sedans

Oikawa Shoko,Matsui Yasuhiro,Kubota Naoyuki,Aomura Shigeru,Sorimachi Kazuhiro,Imanishi Akira,Fujimura Takeshi 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.4

This study clarified the features of fatal truck–pedestrian and truck–cyclist accidents by a comparison with sedans. Fatal accident data from the Japanese Institute Traffic Accident Research and Data Analysis (ITARDA) database were analyzed for the years 2012 ~ 2016. The trucks were classified into three categories: heavy-, medium-, and light-duty. All three categories had higher percentages of pedestrians as fatal collision partners as opposed to cyclists. Every truck category had significantly higher percentages of pedestrian fatalities due to daytime right turns than sedans. Heavy-duty trucks had significantly higher percentages of cyclist fatalities due to daytime and nighttime left turns than sedans. These results show that the design specifications for new sensing technology to avoid collisions with pedestrians and cyclists should differ among vehicle types. The knowledge obtained in this study will be useful to develop new technology or systems that are effective in dangerous situations between trucks and pedestrians or cyclists.

CHARACTERISTICS OF RIGHT-TURNING LIGHT-DUTY TRUCK COLLISION ACCIDENTS INVOLVING PEDESTRIANS IN DIFFERENT TIME ZONES

Oikawa Shoko,Matsui Yasuhiro,Kubota Naoyuki,Aomura Shigeru,Sorimachi Kazuhiro,Imanishi Akira,Fujimura Takeshi 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.2

This study attempts to clarify the characteristics of light-duty truck collision accidents involving pedestrians during right-turn maneuvers by analyzing actual pedestrian accident data in Japan. Evidence differences were observed between the daytime and nighttime. The number of injured and fatal pedestrians during the day was larger than that during the night. The rate of vehicle travel velocity ≤ 10 km/h in the daytime (47.0 %) was significantly higher than that in the nighttime (39.2 %), whereas the rate of vehicle travel velocity ≤ 20 km/h in the nighttime (52.7 %) was significantly higher than that in the daytime (46.9 %). The highest rate in the daytime was presented for the age group of 13 ~ 64 years in minor injuries (54.1 %) and for those 75 years or older in serious injuries (47.5 %) and fatalities (64.3 %). For pedestrian crossing directions on the crosswalk, the pedestrian crossing from the forward left-side corner to the right-side corner exhibited the highest percentage in the daytime (39.2 %), and the opposite direction of crossing from the right-side corner to the forward left-side corner exhibited the highest percentage in the nighttime (39.6 %). The characteristics obtained in this study will contribute to the development and evaluation of advanced safety systems that are specialized for right-turning maneuvers of light-duty trucks.