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Crystal orientation-dependent fatigue characteristics in micrometer-sized single-crystal silicon

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Microsystems & Nanoengineering 2016年第1期2卷 154-162页

作者： Tsuyoshi ikehara Toshiyuki Tsuchiya National Institute of Advanced Industrial Science and Technology(AIST) 1-2 NamikiTsukubaIbaraki 305-8564Japan Department of Micro Engineering Graduate School of EngineeringKyoto UniversityKyotodaigaku-Katsura C3Nishikyo-kuKyoto 615-8540Japan

Repetitive bending fatigue tests were performed using five types of single-crystal silicon specimens with different crystal orientations fabricated from{100}and{110}*** lifetimes in a wide range between 100 and 1010 were obtained using fan-shaped resonator test *** surface observation via scanning electron microscope(SEM)revealed that the{111}plane was the primary fracture *** crack propagation exponent n was estimated to be 27,which was independent of the crystal orientation and dopant concentration;however,it was dependent on the surface conditions of the etched *** fatigue strengths relative to the deflection angle were orientation dependent,and the ratios of the factors obtained ranged from 0.86 to *** strength factors were compared with those obtained from finite element method stress *** calculated stress distributions showed strong orientation dependence,which was well-explained by the elastic *** comparison of the strength factors suggested that the first principal stress was a good criterion for fatigue *** include comparisons with specimens tested in our previous report and address the tensile strength,initial crack length,volume effect,and effects of surface roughness such as scallops.

关键词： fatigue fracture lifetime MEMS reliability resonator single-crystal silicon

Evaluation of microstructure and creep damage in high-Cr ferritic steel welds

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Acta Metallurgica Sinica(English Letters) 2011年第3期24卷 225-234页

作者： masaaki TABUCHI Hiromichi HONGO National Institute for Materials Science

11Cr-0.4Mo-2W-CuVNb steel （ASME Gr.122） is used for boiler components in ultra- supercritical （USC） thermal power plants. The creep strength of high-Cr steel welds decreases due to the formation of Type IV creep damage in the heat-affected zone （HAZ） during long-term use at high temperatures. In the present study, the processes and mechanisms of Type Ⅳ creep damage were elucidated by investigating the long-term creep strength, microstructure and damage behavior of Gr.122 steel welds. Creep tests using thick welded joints were interrupted at several time steps, and the initiation, evolution and distribution of creep damage were measured. It was found that the formation and growth of creep damage was suppressed during the steady- state stage; creep voids formed at 0.5 of life, and coalesced to form a crack after 0.9 of life. Type IV creep damage was mostly observed in the area about 30% below the surface of the plate. Differences in creep damage behavior between Gr.122 and Gr.91 steel welds were examined. Experimental creep damage distribution was compared with computed versions using the finite element method and damage mechanics.

关键词： Gr.122 steel Welded joint Creep void Type Ⅳ damage Finite element method Damage mechanics

Creep and creep-fatigue behavior of high chromium steel weldment

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Acta Metallurgica Sinica(English Letters) 2011年第3期24卷 175-182页

作者： Yukio TAKAHASHI masaaki TABUCHI Materials Science Laboratory Central Research Institute of Electric Power Industry National Institute of Material Sciences

Strength of welded joints of high chromium steels is one of the important concerns for fabricators and operators of ultra supercritical thermal power plants. A number of creep as well as creep-fatigue tests with tensile hold have been carried out on the welded joints of two types of high chromium steels widely used in Japan, i.e. Grade 91 and 122 steels. It was found that failure occurred in fine grain heat-affected zone in all the creep-fatigue tests, even at a relatively low temperature and fairly short time where failure occurred in plain base metal region in simple creep testing. Four procedures were used to predict failure lives and their results were compared with the test results. A newly proposed energy-based approach gave the best estimation of failure life, without respect of the material and temperature.

关键词： Creep Creep-fatigue High chromium steel Life prediction Welded joint

Appendix is a priming site in the development of ulcerative colitis

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World Journal of Gastroenterology 2005年第31期11卷 4869-4874页

作者： Mitsunobu Matsushita Hiroshi Takakuwa Yuji Matsubayashi Akiyoshi Nishio Susumu ikehara Kazuichi Okazaki Third Department of Internal Medicine Department of Gastroenterology Department of Gastroenterology and Endoscopic Medicine First Department of Pathology

AIM： The role of the appendix has been highlighted in the pathogenesis of ulcerative colitis （UC）. The aims of this study were to elucidate the immuno-imbalances in the appendix of UC patients, and to clarify the role of the appendix in the development of UC. METHODS： Colonoscopic biopsy specimens of the appendix, transverse colon, and rectum were obtained from 86 patients with UC： active pancolitis （A-Pan; n = 15）, active letf-sided colitis （A-Lt; n = 25）, A-Lt with appendiceal involvement （A-Lt/Ap; n = 10）, inactive pancolitis （I-Pan; n = 14）, and inactive left-sided colitis （I-Lt; n = 22）, and from controls. In the isolated mucosal T cells, the CD4/CD8 ratio and proportion of activated CD4＋ T ceils were investigated, and compared with controls. RESULTS： in the appendix, the CD4/CD8 ratio significantly increased in A-Lt and A-Lt/Ap. The ratio in the appendix also tended to increase in A-Pan. In the rectum, the ratio significantly increased in all UC groups. In the appendix, the proportion of CD4＋CD69＋（early activation antigen） T cells significantly increased in all UC groups. In the rectum, the proportion of CD4＋CD69＋ T cells significantly increased only in A-Pan. The proportion of CD4＋HLADR＋（mature activation antigen） T cells significantly increased only in the rectum of A-Pan, but not in the otherareas of any groups. CONCLUSION： The increased CD4/CD8 ratio and predominant infiltration of CD4＋CD69＋ T cells in the appendix suggest that the appendix is a priming site in the development of UC.

关键词： Appendix Appendectomy Ulcerative colitis Activated T cell CD4+ T cell

Development of Helicobacter pylori treatment: How do we manage antimicrobial resistance?

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World Journal of Gastroenterology 2019年第16期25卷 1907-1912页

作者： Sho Suzuki Mitsuru Esaki Chika Kusano Hisatomo ikehara Takuji Gotoda Division of Gastroenterology and Hepatology Department of Medicine Nihon University School of Medicine

Helicobacter pylori(H. pylori) antimicrobial resistance is an urgent, global issue. In2017, the World Health Organization designated clarithromycin-resistant *** as a high priority bacterium for antibiotic research and development. In addition to clarithromycin, resistance to metronidazole and fluoroquinolones has also increased worldwide. Recent international guidelines for management of *** infection recommend bismuth or non-bismuth quadruple therapy for 14 d as a first-line treatment for H. pylori in areas of high clarithromycin and/or metronidazole resistance. Although these treatment regimens provide acceptable H. pylori eradication rates, the regimens used should not contribute to future resistance of H. pylori to antimicrobials. Moreover, these regimens can promote resistance, due to prolonged therapy with multiple antibiotics. A new strategy that can eradicate H. pylori as well as reduce the antibiotics used is required to prevent future antimicrobial resistance in H. pylori. Dual-therapy with vonoprazan and amoxicillin could be a breakthrough for H. pylori eradication in an era of growing antimicrobial resistance. This regimen may provide a satisfactory eradication rate of H. pylori and also minimize antimicrobial resistance due to single antibiotic use and the strong inhibitory effect of vonoprazan on gastric acid secretion.

关键词： Helicobacter pylori Antibiotic resistance Antimicrobial resistance Dual therapy Vonoprazan

A Partial Order in the Knot Table Ⅱ

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Acta Mathematica Sinica,English Series 2008年第11期24卷 1801-1816页

作者： Teruaki KITANO masaaki SUZUKI Department of Information Systems Science Faculty of Engineering Soka University 1-236 Tangi-cho Hachioji-city Tokyo 192-8577 Japan Department of Mathematics Akita University 1-1 Tegata-Gakuenmachi Akita 010-8502 Japan

A partial order on the set of the prime knots can be defined by the existence of a surjective homomorphism between knot groups. In the previous paper, we determined the partial order in the knot table. In this paper, we prove that 31 and 41 are minimal elements. Further, we study which surjection a pair of a periodic knot and its quotient knot induces, and which surjection a degree one map can induce.

关键词： knot partial order surjective homomorphism period degree one map

Bubble entrapment during the recoil of an impacting droplet

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Microsystems & Nanoengineering 2020年第1期6卷 768-774页

作者： Thanh-Vinh Nguyen masaaki Ichiki Sensing System Research Center National Institute of Advanced Industrial Science and Technology(AIST)Japan1-2-1 NamikiTsukuba-shiIbaraki 305-8564Japan

When a droplet impacts a(super-)hydrophobic surface,there is a range of Weber numbers within which bubble entrapment will occur during droplet recoil due to closure of the air cavity developed when the droplet spreads out during the *** this study,we studied bubble entrapment using a microelectromechanical system(MEMS)-based acoustic sensor fabricated on a *** found that bubble entrapment is followed by an acoustic vibration that can be detected by the ***,the frequency of the vibration is inversely proportional to the radius of the droplet,which indicates that this vibration is the resonant oscillation of the ***,the MEMS-based acoustic sensor can be used not only to detect but also to measure the size of the entrapped ***,we demonstrated that it is possible to prevent bubble formation by allowing the air to escape to the underside of the droplet contact *** can be done by creating through-holes on the substrate or decorating the substrate with sufficiently large textures.

关键词： bubble radius resonant

Electromechanically reconfigurable plasmonic photodetector with a distinct shift in resonant wavelength

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Microsystems & Nanoengineering 2023年第2期9卷 219-226页

作者： masaaki Oshita Shiro Saito Tetsuo Kan Graduate School of Informatics and Engineering The University of Electro-Communications1-5-1ChofugaokaChofu-cityTokyo 182-8585Japan IMRA JAPAN CO. LTD2-36Hachiken-choKariyaAichi 448-8650Japan

Plasmonic photodetectors have received increasing attention because their detection properties can be designed by tailoring their metal structures on surfaces without using any additional *** of the plasmonic resonant state in a photodetector is relevant for various applications,including investigating in situ adaptive detection property changes,depending on the situation,and performing single-pixel spectroscopy in geometrically limited ***,the spectral responsivity change with conventional reconfiguration methods is relatively ***,we propose a plasmonic photodetector that reconfigures its spectral responsivity with electromechanical deformation instead of bias *** photodetector consists of a gold plasmonic grating formed on an n-type silicon cantilever,and the spectral responsivity is reconfigured by electromechanically scanning at an incident angle to the grating on the *** photodetector exhibits peak shifts in spectral responsivity in a wavelength range from 1250 to 1310 nm after electromechanical ***,for potential future applications,we demonstrate near-infrared spectroscopy using the *** photodetector has the potential to be adopted as a near-infrared spectrometer in industrial silicon imaging systems because its structure enables subbandgap photodetection on silicon by a Schottky junction.

关键词： tuning reconfigurable resonant

Velocity Measurement of Induced Flow by a Laser Focusing Shock Wave

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Journal of Thermal Science 2006年第1期15卷 48-53,26页

作者： Hiroyuki HIRAHARA Masaru FUJINAMI masaaki KAWAHASHI Department of Mechanical Engineering Saitama University 255 Shimo-Okubo Sakura Saitama 338-8570Japan. Graduate School of Science and Engineering Saitama University Japan

The objective of this study is to apply the shock wave for control in a micro channel. The shock wave was generated by a laser focusing of pulsed laser beam in the channel. Using a pulse laser to generate a shock wave, a non-stationary flow was induced in the small space between the parallel plates. The spherical and cylindrical shock propagations were observed with schlieren method. The shock Mach number decreases with time and approaches to unity. As reported in the previous investigations, the shock speed was attenuated in a short distance and time. In the present experiment, It was not found a remarkable difference in the shock speed between the spherical and cylindrical shock experiments. Subsequently, the flow induced by the cylindrical shock wave was studied using PIV technique. A smoke tracer was used in the experiment and its velocity was measured within 100 μs. A numerical simulation was carried out to investigate the momentum relaxation between the gas and smoke particle. A suitable shock initiation model was introduced in the simulation. The experimental results show that a wide acceleration and deceleration zone exist behind the shock wave. Also, the relaxation distance in the experimental data is much longer than that in numerical simulation.

关键词： micro-blast wave laser focusing flow visualization PIV.