http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Effects of Ultrasonic Peening on Fatigue Strength of Out-of-plane Gusset Joints
Koji Kinoshita,Akito Imamura,Yoshihiro Watanabe,Mitsuru Handa 한국강구조학회 2014 International Journal of Steel Structures Vol.14 No.4
Effect of high frequency peening treatment with a small radius tip pin, which is less than 3mm radius tip pin, still remainsunclear, although the effect of ultrasonic impact treatment on fatigue strength has been investigated. The objective of this studyis to investigate the effect of ultrasonic peening with a 1.5mm radius tip pin on fatigue strength of out-of-plane gusset weldedjoints. Plate bending fatigue tests of those joints carried out. The results show that the peening can improve fatigue strength,when mean stress does not change or already changes before the peening is carried out. It also shows that the effect of theultrasonic impact peening become less with increasing mean stress after the ultrasonic peening was carried out, and when theultrasonic peening is not sufficient for the weld toe.
Fatigue Strength Improvement of Welded Joints of Existing Steel Bridges by Shot-Peening
Koji Kinoshita,Yuki Banno,Yuki Ono,Shohey Yamada,Mitsuru Handa 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.2
Shot-peening recently can be applied to existing steel bridges due to the development of new vacuuming techniques of shots after peening in the construction site. This study experimentally investigates eff ects of fatigue strength improvement of shot-peening on welded joints. Bending fatigue tests using out-of-plane gusset welded joints specimens were carried out and three type specimens were compared: as-welded, grit-blasted, and shot-peened. In addition, this paper examines diff erences of fatigue strength improvement eff ects in case of applying shot-peening to inside of scallop where shots might be diffi cult to hit perpendicularly to weld toe of welded joints because of narrow space, and the residual stress measurement in order to clarify introducing compressive residual stress were carried out. As a result, it may be concluded that shot-peening can improve fatigue strength of welded joints and its mechanism was identifi ed as extension of crack initiation life and delay crack propagation due to benefi cial compressive residual stress in the vicinity of surface layer.
Koji Kinoshita,Yuki Banno,Yuki Ono,Shohey Yamada,Mitsuru Handa 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.3
This study experimentally investigates eff ect of fatigue strength improvement of the Portable Pneumatic Needle-Peening treatment (PPP treatment) as a needle peening on out-of-plane gusset welded joints by using plate bending fatigue tests. This study also examined eff ect of the travel speed and the number of treatment passes of the PPP treatment with regards to its fatigue strength improvement. After the fatigue tests, the observation of the fracture surface with Scanning Electron Microscope was carried out in order to clarify the crack initiation. From those test results, it may be concluded that the eff ect of fatigue strength improvement might be governed by treatment passes with suffi cient travel speed. In addition, this study carried out additional fatigue tests that focus on fatigue crack closer by using the PPP treatment. As a result of additional fatigue tests for fatigue crack closure, it might be said that the eff ect of fatigue crack closure is eff ective when the distance between fatigue cracks and treatment area is less than 2.0 mm.
Examination on Fatigue Limit and Crack Growth Characteristic of SBHS700 Base Metal
Yuki Ono,Koji Kinoshita 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.4
The object of this study is to clarify fatigue limit and fatigue crack growth characteristic of SBHS700 base metal which is 780 MPa class steel. This study carried out the fatigue tests of SBHS700 base metal containing diff erent defect size, and the fatigue limit was compared with that of the conventional steel. Test results indicate that the fatigue limit increased with decrease initial defect size, and can be precisely evaluated by using √area parameter model. This paper also presents that crack growth characteristic was almost the same as that of the conventional steel from the observation of striations by using Scanning electron microscope and length of beach marks.
Hideki Hayakawa,Quang Dung Le,Masato Kinoshita,Yusuke Takehana,Kei Sakuma,Hirohiko Takeshima,Shigeaki Kojima,Kiyoshi Naruse,Koji Inoue 한국해양과학기술원 2015 Ocean science journal Vol.50 No.2
Ricefishes of the genus Oryzias, including Japanese medaka (O. latipes), are known as excellent model organisms for studies in various fields of science. Some species of the genus inhabit brackish water, and such species are recognized to be useful to investigate physiological phenomena in seawater. However, only a limited number of species have been recorded from brackish waters. In addition, there is no information about the genetic relationship among populations inhabiting sites with different salinities. Here we report the discovery of Oryzias fish in two locations near Haiphong, northern Vietnam, a brackish mangrove planting area and a freshwater pond. A phylogenetic analysis using mitochondrial 12S and 16S ribosomal RNA (rRNA) gene sequences indicated that the fish from the two localities are the same species, Hainan medaka,O. curvinotus. Population genetic analysis using the mitochondrial 12S and 16S rRNA gene sequences revealed a close genetic relationship between the two populations. These results suggest that O. curvinotus is adaptable to both hyperosmotic and hypoosmotic environments. Due to its osmotic adaptability and ease of rearing in the laboratory, this species is expected to become a model for marine environmental and toxicological studies, as well as for studies of osmotic adaptation mechanisms.
Norimoto Masaki,Eguchi Yawara,Kanamoto Hirohito,Oikawa Yasuhiro,Matsumoto Koji,Masuda Yoshitada,Furuya Takeo,Orita Sumihisa,Inage Kazuhide,Maki Satoshi,Shiga Yasuhiro,Kinoshita Hideyuki,Abe Koki,Inoue 대한척추외과학회 2021 Asian Spine Journal Vol.15 No.2
Study Design: Retrospective observational study. Purpose: Lumbar spinal stenosis (LSS) has traditionally been evaluated morphologically, there is a paucity of literature on quantitative assessment of LSS. The purpose of this study was to investigate whether intraspinal diffusion tensor imaging (DTI) parameters such as apparent diffusion coefficient (ADC) and fractional anisotropy (FA) are useful for assessing LSS. Overview of Literature: Quantitative assessment of LSS is challenging. Methods: Study participants comprised five healthy volunteers (mean age, 27.2 years) and 27 patients with LSS (mean age, 58.4 years) who were individually assessed using 3.0 Tesla magnetic resonance imaging. Intraspinal ADC and FA values of 10 intervertebral discs from healthy volunteers and 52 intervertebral discs from LSS patients were measured. Also, intraspinal canal area, Schizas classification (A: normal, B: mild stenosis, C: severe stenosis) and correlations with symptoms were investigated. Clinical symptoms were checked for the presence of low back pain (LBP), intermittent claudication (IMC), and bladder and bowel dysfunction (BBD). Results: Compared to healthy individuals, LSS patients had significantly lower ADC (p <0.05) and significantly higher FA values (p <0.01). In Schizas classification, stenosis worsened from A to C. ADC values decreased significantly while FA values increased significantly in that order (p <0.05). A positive correlation was found between intraspinal canal area and ADC values (r =0.63, p <0.01) and a negative correlation between intraspinal canal area and FA values (p =−0.61, p <0.01). No correlations were noted between LBP and ADC or FA values. On the other hand, ADC values were significantly lower (p <0.05) and FA values were significantly higher (p <0.05) in patients with IMC or BBD. Conclusions: Intraspinal DTI parameters such as ADC and FA values were associated with the Schizas classification, intraspinal canal area, and clinical symptoms, suggesting that ADC and FA may be useful for quantitative assessment of LSS.
Aina Kunitomo,Kazunari Misawa,Yuichi Ito,Seiji Ito,Eiji Higaki,Seiji Natsume,Takashi Kinoshita,Tetsuya Abe,Koji Komori,Yasuhiro Shimizu 대한위암학회 2021 Journal of gastric cancer Vol.21 No.4
Purpose: Type 4 gastric cancer (GC) has a very poor prognosis even after curative resection, and the survival benefit of splenectomy for splenic hilar lymph node (LN; #10) dissection in type 4 GC remains equivocal. This study aimed to clarify the clinical significance of splenectomy for #10 dissection in patients with type 4 GC. Materials and Methods: The data of a total of 56 patients with type 4 GC who underwent total gastrectomy with splenectomy were retrospectively analyzed. Postoperative morbidity, state of LN metastasis, survival outcomes, and therapeutic value index (TVI) of each LN station were evaluated. TVI was calculated by multiplying the incidence of LN metastasis at each nodal station and the 5-year overall survival (OS) of patients who had metastasis to each node. Results: Overall, the postoperative morbidity rate was 28.6%, and the incidence of #10 metastasis in the patients was 28.6%. The 5-year OS rate for all patients was 29.9%, and most patients developed peritoneal recurrence. Moreover, the 5-year OS rates with and without #10 metastasis were 6.7% and 39.1% (median survival time, 20.4 vs. 46.0 months; P=0.006). The TVI of #10 was as low as 1.92. Conclusions: The clinical significance of splenectomy in the dissection of #10 for type 4 GC is limited and splenectomy for splenic hilar dissection alone should be omitted.
Kanamoto Hirohito,Norimoto Masaki,Eguchi Yawara,Oikawa Yasuhiro,Orita Sumihisa,Inage Kazuhide,Abe Koki,Inoue Masahiro,Kinoshita Hideyuki,Umimura Tomotaka,Matsumoto Koji,Masuda Yoshitada,Furuya Takeo,K 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.3
Study Design: Observational study.Purpose: To evaluate healthy volunteers and patients with spinal canal lesions using apparent diffusion coefficient (ADC) maps with diffusion-weighted imaging.Overview of Literature: Decompression surgery for lumbar spinal stenosis (LSS) is selected on the basis of subjective assessment and cross-sectional magnetic resonance imaging (MRI). However, there is no objective standard for this procedure.Methods: We performed 3T MRI in 10 healthy volunteers and 13 patients with LSS. The ADC values in the spinal canal were evaluated at 46 vertebrae (L4/5 and L5/S1 for each participant), and the reduced and conventional fields of view were compared.Results: The ADC values were 2.72±0.12 at L4/5 in healthy volunteers, 2.76±0.19 at L5/S1 in healthy volunteers, 1.77±0.58 at L4/5 in patients with LSS, and 2.35±0.29 at L5/S1 in patients with LSS. The ADC value at L4/5 in patients with LSS was significantly lower than that at L5/S1 in patients with LSS and that at L4/5 and L5/S1 in healthy volunteers (<i>p</i> <0.05). With an ADC cutoff value of 2.46 to identify LSS, this approach provided an area under the curve of 0.81, sensitivity of 0.92, and specificity of 0.76 (<i>p</i> <0.05).Conclusions: Preoperative examination using ADC maps permits visualization and quantification of spinal canal lesions, thus proving the utility of ADC maps in the selection of decompression surgery for LSS.