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Journal of Materials Science & Technology 2021年第26期85卷 158-168页

作者： Xiaopei Wang yoshiaki morisada Hidetoshi Fujii Joining and Welding Research Institute Osaka University11-1 MihogaokaIbarakiOsaka 567-0047Japan

Dissimilar welding of AZ31/ZK60 magnesium alloys with a thickness of 2 mm was successfully carried out by the double-sided friction stir spot welding with adjustable probes.A dissimilar joint bearing flat surfaces on both sides without a keyhole was obtained and the shear failure load of 8.7±0.5 kN was *** role of the adjustable probes has been revealed in *** the center of the stir zone,the welding interface structure was heterogeneous around which some distinct oxides still remained,leading to a weak interface *** the contrary,the welding interface structure around the shoulder/probe interface was homogeneous with no oxides giving rise to a strong interface strength,which is attributed to the severe material flow introduced by the adjustable *** addition,the vicinity outside the shoulder/probe interface,where the fracture occurred during the shear tensile tests,was also strengthened owing to the shearing and torsion by the adju stable ***,a stable plug failure can be obtained and the joint properties can be improved.

关键词： Friction stir spot welding Dissimilar welding Interface strengthening Microstructure Magnesium alloys

Flat friction stir spot welding of low carbon steel by double side adjustable tools

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Journal of Materials Science & Technology 2021年第7期66卷 1-9页

作者： Xiaopei Wang yoshiaki morisada Hidetoshi Fujii Joining and Welding Research Institute Osaka University11-1 MihogaokaIbarakiOsaka 567-0047Japan

2 mm low carbon steel plates were successfully welded by the flat friction stir spot welding(FSSW) using double side adjustable tools, by which the keyhole formed in the conventional FSSW was eliminated and a flat surface on both the top and bottom sides of the welded joints was obtained. In addition, the hook shape usually generated in the conventional FSSW was eliminated by this technique, and the unbonded interface was parallel to the surface of the sheets. Owing to the enlarged bonded interface width by eliminating the keyhole and the intermixed interface by the adjustable probe, the plug fracture occurred under all the welding conditions in the present study. Due to the suppression of the thickness thinning and elimination of the hook shape, the joint performance was improved in the plug fracture mode. The shear tensile performance was considered to strongly depend on the microstructure in the tip area of the unbonded interface and the maximum shear fracture load of 23.0 kN was achieved in this study.

关键词： Friction stir spot welding Interface structure Low carbon steel Mechanical properties Microstructure

Effect of Ca addition on the microstructure and the mechanical properties of asymmetric double-sided friction stir welded AZ61 magnesium alloy

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Journal of Magnesium and Alloys 2020年第1期8卷 91-102页

作者： Mengran Zhou yoshiaki morisada Hidetoshi Fujii Joining and Welding Research Institute(JWRI) Osaka UniversityJapan

The effects of 2%Ca addition on the microstructure and the mechanical properties of the asymmetric double-sided friction stir welded magnesium alloy AZ61 were *** to the Ca-free AZ61magnesium alloy,the addition of 2%Ca significantly refines the grains in the stir zone after *** to the existence of thermally stable Al2Ca particles,there is no noticeable change in the grain size in the stir zone regardless of the welding heat *** electron backscattered diffraction analysis at the center of the stir zone confirmed the significant deterioration of the(0001)texture strength from the addition of 2%*** tensile test of the joint suggested that the addition of 2%Ca provides stable tensile properties to the joint regardless of the welding *** critical(0001)texture strength that determines the ultimate tensile strength decreased from 20 to 15 by the Ca *** addition of Ca enhanced the deterioration of the plastic elongation when the(0001)texture strength increased.

关键词： Mg alloy Friction stir welding Microstructure Mechanical properties Texture

Quasi-in-situ investigation into the microstructure and texture evolution of pure magnesium during friction stir welding

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Journal of Magnesium and Alloys 2020年第4期8卷 1071-1083页

作者： Zhou Mengran Sun Yufeng morisada yoshiaki Ushioda Kohsaku Fujii Hidetoshi Joining and Welding Research Institute Osaka UniversityOsaka 567-0047Japan The State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China School of materials science and engineering Zhengzhou UniversityZhengzhou 450001China

The quasi-in-situ microstructure and texture evolution along the real flow path of pure magnesium during friction stir welding were *** representative stages were involved from the base metal to the formation of the final stir *** material experienced compression,preheating,acceleration,deceleration,and subsequent annealing over the course of the welding process.A highly concentrated(0001)texture,denoted as''orientation convergence^,was initiated at the beginning of the acceleration stage(shearing deformation zone)in front of the *** continuous and discontinuous dynamic recrystallization occurred simultaneously in the stir zone,and continuous dynamic recrystallization was determined to be the primary recrystallization *** marker material morphology and EBSD data were used to elucidate the in-situ evolution of the shear direction and shear plane along with the real flow path.

关键词： Magnesium Friction stir welding Texture evolution Material flow EBSD

Effect of the processing route on the microstructure and mechanical behavior of superlight Mg-9Li-1Zn alloy via friction stir processing

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Journal of Magnesium and Alloys 2022年第11期10卷 3064-3081页

作者： Mengran Zhou Zhuoran Zeng Chun Cheng yoshiaki morisada Qingyu Shi Jian-Yih Wang Hidetoshi Fujii Joining and Welding Research Institute(JWRI) Osaka UniversityOsakaJapan Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China State Key Laboratory of Tribology Tsinghua UniversityBeijingChina Key Laboratory for Advanced Materials Processing Technology Ministry of Education of China Tsinghua UniversityBeijing 100084China College of Engineering and Computer Science Australian National UniversityACT 2601Australia Department of Materials Science and Engineering National Dong-Hwa UniversityHwa-LianTaiwanChina

In this study, the effect of the processing route using a friction stir processing(FSP) method on the microstructure and mechanical behavior of a Mg-9Li-1Zn alloy was systematically investigated. In the FSP method, the odd-numbered(1st and 3rd) process directions and even-numbered(2nd and 4th) passes were alternated to distribute the strain throughout the whole processed zone uniformly. Consequently, the processed zone had a much more uniform microstructure and hardness distribution than the processed zone obtained using the conventional FSP method. Using this method, the grain size of a Mg-9Li-1Zn sheet alloy was refined from ~31 μm to ~0.21 μm with uniformly distributedα and β phases. The processed alloy exhibited a high strength-ductility synergy with an ultimate tensile strength(UTS) of 220.1 MPa and total elongation of 70.0% at a strain rate of 10^(-3)s^(-1), overwhelmingly higher than those of the base metal, 155.6 MPa in UTS and 36.0%in elongation. The in-situ SEM-DIC analysis and TEM observation demonstrated that such an outstanding ductility with moderate strength is caused by grain boundary sliding, the dominant deformation mechanism of the ultra-fine-grained sample after FSP. The processing route with reverse processing direction was proven to be efficient in producing the ultrafine grain size microstructure and improving the mechanical properties of superlight Mg-9Li-1Zn alloy.

关键词： Mg-Li-Zn alloy Friction stir processing Microstructure In-situ SEM-DIC Mechanical properties

Friction stir spot welding of SPCC low carbon steel plates at extremely low welding temperature

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Journal of Materials Science & Technology 2019年第5期35卷 733-741页

作者： Y.F.Sun H.Fujii Y.Sato Y.morisada Joining and Welding Research Institute Osaka University 11-1 Mihogaoka Ibaraki 567-004Japan School of Materials Science and Engineering Zhengzhou University Zhengzhou 450001 China

Friction stir spot welding (FSSW) was applied to 2.0 mm thick steel plate cold-rolled commercial (SPCC) low carbon steel plates at a very low rotation speed that ranged from 5 to 50rpm, which was much lower than that generally used for the conventional FSSW technique. Due to the very low heat input, the welding processes could therefore be completed at a peak welding temperature below 160℃. As a result, a significantly refined microstructure with an average grain size of about 0.41μm was formed in the stir zone of the joints and the JI {0-11 } and J2{1-1O} shear textures were the dominant components, which are different from the D1{11-2} and D2{-1-12} shear textures formed in the conventional FSSW joints. In addition, no heat affected zone could be detected along the crosssectional plane of the joints. Although a few void-like non-bonded areas were still observed along the interface between the upper and lower steel plates, the shear tensile loads of the joints increased to about 10.0 kN when welded at a condition of 8t, 20rpm and 30 s, and the joints fractured through the plug failure mode.

关键词： Friction stir spot welding Dynamic recrystallization Microstructure Steel

Papain Activity in Dextran Solution for Keratin Hydrolysis

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Advances in Enzyme Research 2014年第1期2卷 49-53页

作者： Nanami Hara Shintaro morisada Keisuke Ohto Hidetaka Kawakita Department of Applied Chemistry Saga University Saga Japan

High concentration of polymer solution in cosmetics has the essential role in keeping water on peel of skin. This study includes the papain activity in the high concentrated dextran solution for keratin hydrolysis. Papain is the industrial and a representative hydrolase. The concentration of dextran was ranged to 100 g/L. In the increasing concentration of dextran, the activity of papain decreased due to the low diffusivity of papain and substrate. Even in concentrated dextran solution, keratin powder was possible to be hydrolyzed at the high efficiency.

关键词： Dextran Papain Keratin Hydrolysis

Neoadjuvant chemotherapy for locally advanced cervical cancer

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Chinese Journal of Cancer Research 2016年第2期28卷 235-240页

作者： Takashi Iwata Azumi Miyauchi Yukako Suga Hiroshi Nishio Masaru Nakamura Akiko Ohno Nobumaru Hirao Tohru morisada Kyoko Tanaka Hiroki Ueyama Hidemichi Watari Daisuke Aoki Department of Obstetrics and Gynecology Keio University School of Medicine Department of Obstetrics and Gynecology Hokkaido University Graduate School of Medicine

Neoadjuvant chemotherapy followed by surgery （NCS） has not been fully evaluated clinically. Currently, the main regimen of neoadjuvant chemotherapy （NAC） used in NCS includes cisplatin. The antitumor effects of NAC reduce lymph node metastasis and the tumor diameter in patients prior to surgery, and this can reduce the number of high risk patients who require postoperative radiation therapy. Many randomized controlled trials （RCTs） have examined the long-term prognosis of NCS compared to primary surgery, but the utility of NCS remains uncertain. The advent of concurrent chemoradiotherapy （CCRT） has markedly improved the outcome of radiotherapy （RT）, and CCRT is now used as a standard method in many cases of advanced bulky cervical cancer. NCS gives a better treatment outcome than radiation therapy alone, but it is important to verify that NCS gives a similar or better outcome compared to CCRT.

关键词： Neoadjuvant chemotherapy (NAC) cervical cancer

Total Laparoscopic Hysterectomy for Diagnosis and Treatment of Cervical Cystic Lesions: A Case Series

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Open Journal of Obstetrics and Gynecology 2020年第3期10卷 357-364页

作者： Tohru morisada Kohsei Tanaka Tomoko Iijima Azumi Nishizawa Hiroshi Nishio Yusuke Kobayashi Masaru Nakamura Shigenori Hayashi Fumio Kataoka Takashi Iwata Daisuke Aoki Department of Obstetrics and Gynecology Keio University School of Medicine Tokyo Japan

Objective: Cervical cystic lesions are often observed in gynecological clinical practice. Many are caused by benign diseases such as lobular endocervical glandular hyperplasia (LEGH), and it is important to differentiate these lesions from those due to malignant diseases such as minimal deviation adenocarcinoma (MDA). In cases in which fertility preservation is not a concern, the final pathology is often confirmed by hysterectomy. To investigate the feasibility and safety of laparoscopic surgery for cervical cystic lesions, we retrospectively examined cases in which total laparoscopic hysterectomy (TLH) was performed for diagnosis and treatment. Methods: The subjects were 28 women who underwent TLH from April 2012 to March 2017 at Keio University Hospital. The pre- and post-operative courses of these patients were examined. Results: The average age was 49.4 (range 39 - 65) years and the mean body mass index was 21.7 (16.8 - 30.5) kg/m2. The average operation time was 159 (101 - 314) min and the average bleeding volume was 106.8 (0 - 600) g. There were no severe perioperative complications. The average hospital stay was 8.4 (7 - 14) days. In postoperative pathological diagnosis, 13 cases had benign diseases such as Nabot cysts, there were 14 cases of LEGH, and one patient was diagnosed with MDA. In the MDA case, additional bilateral salpingo-oophorectomy and pelvic lymph node dissection were performed at a later date. No metastasis was observed in these excised specimens. Conclusions: Our results suggest that TLH for cervical cystic lesions can be performed safely. However, it is important to consider the TLH indication before surgery based on the possibility of malignant disease.

关键词： Lobular Endocervical Glandular Hyperplasia Minimum Deviation Adenocarcinoma Total Laparoscopic Hysterectomy Uterine Cervix