http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Surface durability of WC/C-coated case-hardened steel gear
Masahiro Fujii,Masanori Seki,Akira Yoshida 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.1
The purpose of this study is to investigate the influence of tungsten carbide/carbon (WC/C) coating on the surface durability of casehardened steel gear. Two kinds of WC/C coatings were deposited on the ground gear pair made of chromium molybdenum steel with carburizing and quenching. One is the conventional WC/C coating, and the other is WC/C coating with about 1 μm CrN interlayer. Here,the WC/C-coated test pinion and the WC/C-coated one with CrN interlayer are represented by WT and ST, respectively. Non-coated test pinion is represented by NT. The surface roughness along the tooth profile direction of WT and ST was almost the same as that of NT. A spur gear test was carried out with an IAE power circulating type gear test rig under EP gear oil lubricating condition. The fatal failure mode of the test pinions was pitting due to surface cracking. The fatigue life of WT was longer than that of NT under a maximum Hertzian stress pmax=1700 MPa. On the other hand, under pmax=1900 MPa, that of WT was as long as that of NT due to the peeling occurrence of the coated layer. Under the comparatively low load condition without peeling occurrence, the surface roughness of WT decreased with the increasing number of cycles, and their fatigue life became longer than that of NT. On the contrary, in the case of ST, the peeling of the coated layer occurred at a comparatively early stage of the gear test, and the dedendum was worn by tens of micrometers. Therefore, in the case of ST, the effect of the WC/C coating disappeared at a comparatively small number of cycles.
Improved oxide-ion conductivity of NdBaInO<sub>4</sub> by Sr doping
Fujii, Kotaro,Shiraiwa, Masahiro,Esaki, Yuichi,Yashima, Masatomo,Kim, Su Jae,Lee, Seongsu The Royal Society of Chemistry 2015 Journal of Materials Chemistry A Vol.3 No.22
<▼1><P>The oxide-ion conductivity of NdBaInO4 has been increased by Sr doping.</P></▼1><▼2><P>The oxide-ion conductivity of NdBaInO4 has been increased by Sr doping. Nd0.9Sr0.1BaInO3.95 showed the highest electrical conductivity among Nd1−xSrxBaInO4−x/2 (<I>x</I> = 0.0, 0.1, 0.2, and 0.3). The oxide-ion conductivity <I>σ</I>ion of Nd0.9Sr0.1BaInO3.95 (<I>σ</I>ion = 7.7 × 10<SUP>−4</SUP> S cm<SUP>−1</SUP>) is about 20 times higher than that of NdBaInO4 (<I>σ</I>ion = 3.6 × 10<SUP>−5</SUP> S cm<SUP>−1</SUP>) at 858 °C, and the activation energy of oxide-ion conduction is a little lower for Nd0.9Sr0.1BaInO3.95 (0.795(10) eV) than that for NdBaInO4 (0.91(4) eV). The structure analysis based on neutron powder diffraction data revealed that the Sr exists at the Nd site and oxygen vacancies are observed in Nd0.9Sr0.1BaInO3.95. This result indicates that the increase of the oxide-ion conductivity is mainly due to the increase of the carrier concentration. The bond valence-based energy landscape indicated two-dimensional oxide-ion diffusion in the (Nd,Sr)2O3 unit on the <I>bc</I>-plane and a decrease of the energy barrier by the substitution of Nd with Sr cations.</P></▼2>
Shiraiwa, Masahiro,Fujii, Kotaro,Esaki, Yuichi,Kim, Su Jae,Lee, Seongsu,Yashima, Masatomo Electrochemical Society 2017 Journal of the Electrochemical Society Vol.164 No.13
<P>BaNdInO4 is a new structure family of oxide-ion conductors. In the present work, we have investigated the crystal structure and electrical conductivity of Ba1+xNd1-xInO4-x/2 where x is the excess Ba content. It was found that Ba1.1Nd0.9InO3.95 shows (i) about 12 times higher oxide-ion conductivity at 858 degrees C and (ii) a little lower activation energy for oxide-ion conduction than BaNdInO4. The higher oxide-ion conductivity of Ba1.1Nd0.9InO3.95 is mainly ascribed to higher carrier concentration. Careful structure analyses using both the single-crystal X-ray diffraction and time-of-flight (TOF) neutron powder diffraction data enabled to determine the position of excess Ba cation and occupancy factor of O anion. It was found that the excess Ba cation substitutes for Nd cation and that oxygen vacancies exist in Ba1.1Nd0.9InO3.95. The refined occupancy factor of oxygen atom 0.9829(17) indicates the higher concentration of oxygen vacancies in Ba1.1Nd0.9InO3.95, compared with BaNdInO4, giving higher oxide-ion conductivity in Ba1.1Nd0.9InO3.95. The larger-sized Ba substitution for Nd cation makes the bottleneck size larger, leading to the lower activation energy. The bond valence-based energy landscape calculated for the refined crystal structure of Ba1.1Nd0.9InO3.95 at 800 and 24 degrees C indicated two-dimensional oxide-ion diffusion in the A rare earth oxide (Nd, Ba)(2)O-3 unit on the bc plane. (c) 2017 The Electrochemical Society. All rights reserved.</P>
Surface durability of powder-forged roller treated by shot peening
Masanori Seki,Masahiro Fujii,Yuji Kobayashi,Masaaki Sato,Akira Yoshida 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.1
To investigate the influence of shot peening on the surface durability of powder-forged rollers, the case-hardened powder-forged rollers with a forging density of 7.5 g/cm3 treated by the single shot peening and the double shot peening were fatigue-tested under a slidingrolling contact condition. The surface roughness, the surface hardness and the surface compressive residual stress of the rollers were increased by the shot peening. In addition, the pores near the roller surface were deformed by the shot peening. The failure mode of all the test rollers was spalling due to subsurface cracking. The fatigue lives of all the test rollers were improved by the shot peening, and that of the test roller S08, which was shot-peened with the hardest steel shots in this experimental range, was especially improved. The surface durability of the test roller S08 was also most improved by the shot peening. Cracks became difficult to occur and propagate under the roller surface since the pores near the roller surface were deformed by the stronger shot peening. In this study, double shot peening,which generally restrains the increase in surface roughness, was not particularly effective for the improvement in the surface durability of the powder-forged rollers, because the influence of tangential force on fatigue was not always great in a case of subsurface cracking.
Sakanaka, Katsuyuki,Itasaka, Satoshi,Ishida, Yuichi,Fujii, Kota,Horimatsu, Takahiro,Mizowaki, Takashi,Sakai, Yoshiharu,Hiraoka, Masahiro The Korean Society for Radiation Oncology 2017 Radiation Oncology Journal Vol.35 No.4
Purpose: The purpose of this study was to explore the dosimetric difference between simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) and three-dimensional conformal radiotherapy (3DCRT), and the clinical outcomes of anal squamous cell carcinoma (ASCC) chemoradiotherapy featuring SIB-IMRT. Materials and Methods: This study included ten patients with ASCC who underwent chemoradiotherapy using SIB-IMRT with 5-fluorouracil and mitomycin C. SIB-IMRT delivered 54 Gy to each primary tumor plus metastatic lymph nodes and 45 Gy to regional lymph nodes, in 30 fractions. Four patients received additional boosts to the primary tumors and metastatic lymph nodes; the median total dose was 54 Gy (range, 54 to 60 Gy). We additionally created 3DCRT plans following the Radiation Therapy Oncology Group 9811 protocol to allow dosimetric comparisons with SIB-IMRT. Locoregional control, overall survival, and toxicity were calculated for the clinical outcome evaluation. Results: Compared to 3DCRT, SIB-IMRT significantly reduced doses to the external genitalia, bladder, and intestine, delivering the doses to target and elective nodal region. At a median follow-up time of 46 months, 3-year locoregional control and overall survival rates were 88.9% and 100%, respectively. Acute toxicities were treated conservatively. All patients completed radiotherapy with brief interruptions (range, 0 to 2 days). No patient experienced ${\geq}grade$ 3 late toxicity during the follow-up period. Conclusion: The dosimetric advantages of SIB-IMRT appeared to reduce the toxicity of chemoradiotherapy for ASCC achieving high locoregional control in the extended period.
Katsuyuki Sakanaka,Satoshi Itasaka,Yuichi Ishida,Kota Fujii,Takahiro Horimatsu,Takashi Mizowaki,Yoshiharu Sakai,Masahiro Hiraoka 대한방사선종양학회 2017 Radiation Oncology Journal Vol.35 No.4
Purpose: The purpose of this study was to explore the dosimetric difference between simultaneous integrated boost intensitymodulated radiotherapy (SIB-IMRT) and three-dimensional conformal radiotherapy (3DCRT), and the clinical outcomes of anal squamous cell carcinoma (ASCC) chemoradiotherapy featuring SIB-IMRT. Materials and Methods: This study included ten patients with ASCC who underwent chemoradiotherapy using SIB-IMRT with 5-fluorouracil and mitomycin C. SIB-IMRT delivered 54 Gy to each primary tumor plus metastatic lymph nodes and 45 Gy to regional lymph nodes, in 30 fractions. Four patients received additional boosts to the primary tumors and metastatic lymph nodes; the median total dose was 54 Gy (range, 54 to 60 Gy). We additionally created 3DCRT plans following the Radiation Therapy Oncology Group 9811 protocol to allow dosimetric comparisons with SIB-IMRT. Locoregional control, overall survival, and toxicity were calculated for the clinical outcome evaluation. Results: Compared to 3DCRT, SIB-IMRT significantly reduced doses to the external genitalia, bladder, and intestine, delivering the doses to target and elective nodal region. At a median follow-up time of 46 months, 3-year locoregional control and overall survival rates were 88.9% and 100%, respectively. Acute toxicities were treated conservatively. All patients completed radiotherapy with brief interruptions (range, 0 to 2 days). No patient experienced ≥grade 3 late toxicity during the follow-up period. Conclusion: The dosimetric advantages of SIB-IMRT appeared to reduce the toxicity of chemoradiotherapy for ASCC achieving high locoregional control in the extended period.