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Oxidation behavior and improvement in nonflammability of LPSO-type Mg–Zn–Y–Sr alloy

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Journal of Magnesium and Alloys 2024年第2期12卷 742-749页

作者： Shin-ichi Inoue Kazumasa Iwanaga Yoshihito kawamura Magnesium Research Center Kumamoto University2-39-1 KurokamiChuo-kuKumamoto 860-8555Japan Department of Materials Science Graduate School of Science and TechnologyKumamoto University2-39-1 KurokamiChuo-kuKumamoto 860-8555Japan

Mg_(97)Zn_(1)Y_(2)alloys with high ignition temperatures were developed by adding *** addition of Sr resulted in the formation of a uniform and thin Y_(2)O_(3)***–Zn–Y alloys containing at least 0.25 at.%Sr exhibited ignition temperatures of 1270–1320 *** a result of EDS measurement,Sr was found to be concentrated in the Y_(2)O_(3)*** addition,a mixed film of MgO and Sr O formed on the outer layer in the 1.5 at.%Sr-containing Mg_(97)Zn_(1)Y_(2)*** findings suggest that the uniform and thin Y_(2)O_(3)film that maintains high soundness at high temperatures was formed owing to valence control and the formation of a protective outer oxide film.

关键词： Magnesium alloy Yttrium Strontium High-temperature oxidation Nonflammability

Droplet morphology analysis of drop-on-demand inkjet printing

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China Foundry 2024年第1期21卷 20-28页

作者： Hu-xiang Xia Takechi Kensuke Tajima Shin kawamura Yoshiumi Qing-yan Xu Key Laboratory for Advanced Materials Processing Technology(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Toyota Central R&D Labs. Inc.41-1 Yokomichi NagakuteAichi 480-1192Japan Frontier Research Center Toyota Motor Corporation1 Toyota-ChoToyotaAichi 471-8572Japan

As an accurate 2D/3D fabrication tool,inkjet printing technology has great potential in preparation of micro electronic *** morphology of droplets produced by the inkjet printer has a great impact on the accuracy of *** this study,the drop-on-demand(DoD)inkjet simulation model was established,and the accuracy of the simulation model was verified by corresponding *** simulation result shows that the velocity of the droplet front and tail,as well as the time to disconnect from the nozzle is mainly affected by density(ρ),viscosity(μ)and surface tension(σ)of *** the liquid filament is about to disconnect from the nozzle,the filament length and filament front velocity are found to have a linear correlation withσ/ρμand ln(ρ/(μσ1/2)).

关键词： microdevice fabrication inkjet printing droplet morphology modeling and simulation

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最新铁路变电所设备新的环保产品

西铁科技 2006年第2期 50-52页

作者： naoki kawamura Tetsuya Kato Yoshimasa Eda Hirotaka Takahashi 宋文伟

为了缩小铁路变电所装置的体积、降低损耗、便于维修，日立公司研制出了体积小、坚固耐用的SF6GIS（气体绝缘开关装置），噪声低、效率高的电气化铁路变压器和数控电源柜。为满足目前不断增长的环保、安全、高效、坚固、便于维修设备的... 详细信息

为了缩小铁路变电所装置的体积、降低损耗、便于维修，日立公司研制出了体积小、坚固耐用的SF6GIS（气体绝缘开关装置），噪声低、效率高的电气化铁路变压器和数控电源柜。为满足目前不断增长的环保、安全、高效、坚固、便于维修设备的需求，我们研制出了（1）环保型防故障硅变压器；（2）无SF6温室气体环保型GIS和坚固型叠放式SWGR（开关装置）；（3）一种新的不含PFCs（全氟化碳气体）冷却液的生态型低损耗整流器；（4）BBU（组合单元），通过采用标准单元的保护控制器，实现在线维修。

关键词：铁路变电所维修设备气体绝缘开关装置 SF6GIS 降低损耗电气化铁路保护控制器环保型日立公司温室气体

In-situ study of the microstructure evolution during tension of a Mg-Y-Zn-Al alloy processed by rapidly solidified ribbon consolidation technique

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Journal of Magnesium and Alloys 2024年第5期12卷 2024-2040页

作者： Jeno Gubicza Kristián Máthis Péter Nagy Péter Jenei Zoltán Hegedus Andrea Farkas Jozef Vesely Shin-ichi Inoue Daria Drozdenko Yoshihito kawamura Department of Materials Physics Faculty of ScienceEotvos Loránd UniversityPázmány P.sétány 1/ABudapest H-1117Hungary Department of Physics of Materials Faculty of Mathematics and PhysicsCharles UniversityKe Karlovu 512116 Praha 2Czech Republic Deutsches Elektronen-Synchrotron DESY Notkestr.85Hamburg 22603Germany Magnesium Research Center Kumamoto University2-39-1 KurokamiChuo-kuKumamoto 860-8555Japan

Mg-Y-Zn-Al alloys processed by rapidly solidified ribbon consolidation(RSRC)technique exhibit an exceptional mechanical performance indicating promising application *** material has a bimodal microstructure consisting of fine recrystallized and coarse non-recrystallized grains with solute-rich stacking faults forming cluster arranged layers(CALs)and nanoplates(CANaPs),or complete long period stacking ordered(LPSO)*** order to reveal the deformation mechanisms,in-situ synchrotron X-ray diffraction line profile analysis was employed for a detailed study of the dislocation arrangement created during tension in Mg-0.9%Zn-2.05%Y-0.15%Al(at%)*** uncovering the effect of the initial microstructure on the mechanical performance,additional samples were obtained by annealing of the as-consolidated specimen at 300 and 400℃ for 2 *** heat treatment at 300℃ had no significant effect on the initial microstructure,its evolution during tension and,thus,the overall deformation behavior under tensile *** the other hand,annealing at 400℃ resulted in a significant increase of the recrystallized grains fraction and a decrease of the dislocation density,leading to only minor degradation of the mechanical *** maximum dislocation density at the failure of the samples corresponding to the plastic strain of 10-25% was estimated to be about 16-20×10^(14)m^(-2).The diffraction profile analysis indicated that most dislocations formed during tension were of non-basal and pyramidal types,what was also in agreement with the Schmid factor values revealed independently from orientation *** was also shown that the dislocation-induced Taylor hardening was much lower below the plastic strain of 3% than above this value,which was explained by a model of the interaction between prismatic dislocations and CANaPs/LPSO plates.

关键词： Mg-Zn-Y-Al alloy Long period stacking ordered(LPSO)phase Cluster arranged nanoplates(CANaPs) Annealing Tension Dislocation density Hardening

Usefulness of Newly Devised Clomiphene Citrate Administration Method Compared with the Conventional Method in Ovulation and Pregnancy

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Open Journal of Obstetrics and Gynecology 2024年第4期14卷 637-649页

作者： Makoto kawamura Misaki Akiyama Remi Nakajima Eri Satoi Yoko Ogaki Rieko Kanda Department of Obstetrics and Gynecology Kohseichuo General Hospital Tokyo Japan

Objective: Since not all women wish to conceive a child through aggressive treatment, we investigated the usefulness of modified repeated intracyclic clomiphene citrate (CC) therapy (repeated CC therapy) as a newly devised administration method. Methods: We evaluated the effects of CC administration on menstrual cycle length and retrospectively compared ovulation and pregnancy in 220 women who received CC at our hospital. Patients in the conventional method group received 50 mg per day for five days, starting on the fifth day of menstruation (withdrawal bleeding). Groups with and without menstrual cycle shortening after conventional CC administration were compared. The repeated CC therapy group was also compared with the non-shortened group. Repeated CC therapy was administered for the first five days as in the conventional method, and a second five-day repeat treatment was administered after an interval of five to seven days. Pregnancy rates, including indirect pregnancies, were evaluated by three different methods. Results: Ovulation and pregnancy rates were significantly better in the shortened group than in the non-shortened group (P < 0.001 and P = 0.010, respectively). Even in the non-shortened group, ovulation and pregnancy rates including indirect pregnancies were significantly improved when ovulation was observed with repeated CC therapy (P < 0.001 and P = 0.022, respectively). Conclusions: For patients whose menstrual cycle was not improved or shortened, repeated CC therapy as the newly devised CC administration method is useful as the next step after the conventional CC administration method.

关键词： Clomiphene Citrate Infertility Menstrual Cycle Ovulation Induction

Adult-Type Granulosa Cell Tumor with Similar Clinical Findings Seen during Ovarian Cystectomy Performed at the Same Time as Laparoscopic Ovarian Drilling for Polycystic Ovarian Syndrome: An Extremely Rare Case

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Open Journal of Obstetrics and Gynecology 2024年第8期14卷 1197-1206页

作者： Remi Nakajima Risa Kobayashi Marie Kawai Eriko Sakamoto Miho Matsuda Rieko Kanda Makoto kawamura Department of Obstetrics and Gynecology Kohseichuo General Hospital. Tokyo Japan

Polycystic ovary syndrome (PCOS) is a major cause of anovulatory infertility. Laparoscopic ovarian drilling (LOD) is a treatment for PCOS that allows the laparoscopic identification of other intra-abdominal lesions and the provision of diagnostic treatment. This study reports a case of PCOS with an ovarian mass in which LOD was aggressively used and a granulosa cell tumor (GCT) was found. A 34-year-old woman with secondary amenorrhea and irregular menstrual cycles presented to the emergency department with abdominal pain of unknown etiology. Imaging studies revealed a 6-cm left ovarian mass with an internal appearance suggestive of a hemorrhage. The patient’s secondary amenorrhea was subsequently diagnosed as PCOS, and LOD was performed to preserve her fertility. Simultaneously, a cystectomy was performed to evaluate the tumor in the left ovary;the diagnosis was adult-type GCT. Although concomitant GCT and PCOS are extremely rare, the two conditions have similar clinical manifestations. In women of reproductive age, the impact of surgery on future fertility should be considered, and the initial surgical technique should be chosen carefully.

关键词： Polycystic Ovary Syndrome Laparoscopic Ovarian Drilling Granulosa Cell Tumor

Inherited multimodal microstructure evolution of high-fracture-toughness Mg-Zn-Y-Al alloys during extrusion for the consolidation of rapidly solidified ribbons

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Journal of Magnesium and Alloys 2022年第9期10卷 2433-2445页

作者： Soya Nishimoto Michiaki Yamasaki Yoshihito kawamura Department of Materials Science Graduate School of Science and TechnologyKumamoto University2-39-1 KurokamiChuo-kuKumamoto 860-8555Japan Magnesium Research Center Kumamoto University2-39-1 KurokamiChuo-kuKumamoto 860-8555Japan

The mechanisms of multimodal microstructure evolution and the effects of microstructural factors on mechanical properties must be elucidated to design new alloys with superior *** this study,high-fracture-toughness and ductile Mg_(96.75)Zn_(0.85)Y_(2.05)Al_(0.35) alloys were developed using rapidly solidified(RS)ribbon-consolidation technique,and the inherited multimodal microstructure evolution during plastic flow consolidation of the RS ribbons was *** use of extrusion for plastic flow consolidation of the heat-treated RS ribbons produced a multimodal microstructure consisting of the worked grains with high Kernel average misorientation(KAM)angles(Group1),the ultrafine dynamically recrystallized(DRXed)grains with intermediate KAM angles(Group 2),and the fine DRXed grains with low KAM angles(Group 3).Groups 1 and 2 contribute to the alloy strengthening,while Group 3 contributes to improving ductility with strainhardening,resulting in enhancement of the fracture *** form the multimodal microstructure,it was necessary to apply plastic flow with equivalent strains of>2.3 to the heat-treated RS ribbons possessing duplex microstructures with different dispersions of the long-period stacking ordered phase.

关键词： Magnesium alloy Long-period stacking ordered phase Multimodal microstructure Rapid solidification Extrusion Dynamic recrystallization

Integrating the effect of abutments in estimating the average vertical stress of elastic hard rock pillars by combining numerical modelling and artificial neural networks

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Underground Space 2023年第6期13卷 121-135页

作者： Nevaid Dzimunya Yoshiaki Fujii Youhei kawamura Faculty of Engineering Hokkaido UniversitySapporo N13W8Japan

Estimating average vertical pillar stresses is a critical step in designing room-and-pillar *** analytical methods can be used to estimate the vertical stresses acting on the ***,the present analytical methods fail to adequately account for the influence of abutments on the distribution of vertical stresses,especially when applied to narrow panel widths and pillar layouts comprising evenly spaced *** this study,a multi-layer perceptron neural network(MLPNN)was applied to predict the vertical loads of regular pillars more *** of room-and-pillar mine layouts were modeled using a displacement discontinuity method(DDM),and a database of 2355 sampled pillar cases was *** MLPNN was trained based on this database,and its prediction capabilities were further validated using simulations by a finite difference code(i.e.,FLAC3D).The model predictions and the FLAC3D simulations reasonably agreed with a regression coefficient of *** model was also adapted for mine cases with evenly spaced barrier pillars,and its application to a real case study mine has shown to provide accurate pillar stress estimations;hence,this model is suitable for practical use at *** though the MLPNN model cannot be applied universally to all mine situations,it seems as a significant improvement over existing analytical techniques in terms of accounting for the influence of abutments on pillar stresses.

关键词： Pillar stress Abutments Multi-layer perceptron neural network Numerical simulation Room-and-pillar mine

Metal chalcogenide-based photoelectrodes for photoelectrochemical water splitting

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Journal of Energy Chemistry 2022年第10期31卷 189-213,I0005页

作者： Marwa Mohamed Abouelela Go kawamura Atsunori Matsuda Department of Electrical and Electronic Information Engineering Toyohashi University of TechnologyToyohashi 441-8580AichiJapan Petrochemical Department Egyptian Petroleum Research InstituteCairo 11727Egypt

Photoelectrochemical water splitting(PEC-WS)is a promising technique for transforming solar energy into storable and environmentally friendly chemical *** semiconductor photoelectrodes with high light absorption capability,rapid e-/h+separation and transfer,and sufficient chemical stability is vital for developing an efficient PEC-WS *** chalcogenides(MCs)have emerged as promising candidates for light absorbers because of their unique electrical and optical *** this review,we present recent developments in hydrogen generation via PEC-WS using MC-based ***,we present a simple illustration of PEC-WS ***,the current performance of various metal(mono-,di-,and tri-)chalcogenide/semiconductor photoelectrodes in PEC-WS is ***,the charge transfer mechanism at the MC/semiconductor interface and the PEC-WS mechanism is thoroughly ***,we discuss future research perspectives toward developing efficient and stable MC/semiconductor photoelectrodes.

关键词： Photoelectrochemical water splitting Metal chalcogenides Photoelectrode Energy conversion