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Two-photon processes at Belle

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Chinese Physics C 2010年第6期34卷 801-806页

作者： H.nakazawa National Central University

We review recent measurements of pure neutral final state production in the two-photon processes, γγ→π^0π^0 and ηπ^0 at the Belle experiment. In the lower invariant mass region, properties of light scalar mesons are measured by partial wave analysis. In the higher energy region the total and differential cross section are compared with QCD models.

关键词： two-photon cross section resonance

Modulation of Twin Tropical Cyclogenesis by the MJO Westerly Wind Burst during the Onset Period of 1997/98 ENSO

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Advances in Atmospheric Sciences 2003年第6期20卷 882-898页

作者：祝从文 Tetsuo nakazawa 李建平 Chinese Academy of Meteorological Sciences Beijing 100081 LASGInstitute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 Meteorological Research Institute TsukubaJapan 305-0051 LASG Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029

The modulation of twin tropical cyclogenesis in the Indian-western Pacific Oceans by the Madden-Julian Oscillation (MJO) during the onset period of 1997/98 ENSO is explored for the period of September 1996 to June 1997 based on daily OLR, NCEP/NCAR wind vector, and JTWC best track datasets. The MJO westerly wind burst associated with its eastward propagation can result in a series of tropical cyclogeneses in a multi-day interval. Only in the transition seasons are pairs of tropical cyclones observed in both the tropical sectors of the Indian-western Pacific Oceans. Two remarkable twin tropical cyclogeneses probably modulated by the MJO westerly wind burst are found: one is observed in the Indian Ocean in the middle of October 1996, and the other is observed in the Western Pacific Ocean in late May 1997. The twin tropical cyclogenesis in mid-October 1996 is observed when the super cloud cluster separates into two isolated clusters by the enhanced westerly wind, which is accompanied by two independent vortices in the equatorial tropical sectors. The other one, in late-May 1997, however, is characterized by one cyclonic flow that later results in another cyclonic cell in its opposite equatorial sector. Thus, there are two very important conditions for twin cyclogenesis: one is the MJO westerly wind straddling the equator, and the other is the integral super cloud cluster, which later splits into two cloud convective clusters with independent vortices.

关键词： Madden-Julian oscillation westerly wind burst twin tropical cyclogenesis

Recent progress on ultrafast/ultrashort/frequency-stabilized erbium-doped fiber lasers and their applications

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Frontiers of Optoelectronics 2010年第1期3卷 38-44页

作者： Masataka nakazawa Research Institute of Electrical Communication Tohoku University

There are many kinds of fiber lasers in the 1.5 μm band using erbium-doped fiber amplifiers. Our group has been studying and developing advanced fiber lasers, such as 1) 10–40 GHz harmonically mode-locked fiber lasers, 2) femtosecond fiber lasers that use single-wall carbon nanotube（CNT）-doped polymers as a saturable absorber, and 3) frequency-stabilized fiber lasers that employ acetylene C2H2. We will describe recent progress on these fiber lasers and their applications in this article.

关键词： mode-locked erbium fiber laser acetylene frequency-stabilized fiber laser high-speed optical transmission coherent optical transmission

Local oxynitriding of AZ31 magnesium alloy by atmospheric-pressure plasma treatment at room temperature

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Journal of Magnesium and Alloys 2022年第7期10卷 1878-1886页

作者： Kenta nakazawa Tatsuki Ohashi Shotaro Saiki Shoichi Kikuchi Department of Mechanical Engineering Faculty of EngineeringShizuoka University3-5-1JohokuNaka-kuHamamatsu432-8561Japan Graduate School of Integrated Science and Technology Shizuoka University3-5-1 JohokuNaka-kuHamamatsu432-8561Japan

A surface-hardening treatment for AZ31 magnesium alloy using an atmospheric-pressure plasma jet(APPJ)at room temperature was *** is a potential engineering material because it is lightweight;however,magnesium alloys are difficult to heat-treat because of their low flaming *** alloy specimens were irradiated with a localized atmospheric-pressure plasma jet generated by dielectric-barrier discharge for 180 s in *** APPJ excited oxygen and nitrogen molecules in the ambient air,resulting in the formation of an oxynitrided layer;oxygen and nitrogen diffusion layer,on the surface of the magnesium *** hardness and elemental distribution for the treated surface were *** top surface of the APPJ-treated magnesium alloy achieved a maximum hardness of 108 HV,which was~1.7 times greater than that of the untreated *** analysis using an electron-probe microanalyzer revealed strong oxygen and nitrogen signals corresponding to the hardened region of the magnesium alloy,meaning that the hardness increased as a result of the formation of the oxynitrided *** proposed APPJ treatment is a promising approach for locally hardening magnesium alloys without using a heat treatment.

关键词： Magnesium alloy Oxynitriding Atmospheric-pressure plasma jet Hardness Surface modification Diffusion

Additive Manufacturing of Metal Micro-ring and Tube by Laser-Assisted Electrophoretic Deposition with Laguerre-Gaussian Beam

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Nanomanufacturing and Metrology 2021年第4期4卷 271-277页

作者： Kenta nakazawa Syunya Ozawa Futoshi Iwata Graduate School of Integrated Science and Technology Shizuoka University3-5-1 Johoku.Naka-kuHamamatsu 432-8561.Japan Graduate School of Medical Photonics Shizuoka University3-5-1 JohokuNaka-kuHamamatsu 432-8011Japan Research Institute of Electronics Shizuoka University3-5-1 JohokuNaka-kuHamamatsu 432-8011Japan

We report a method for laser-assisted electrophoretic deposition using a Laguerre-Gaussian beam for maskless patterning of metal rings and *** are structures of utmost importance,particularly in photonic *** nanoparticles,which are gathered in a colloidal solution by a laser trapping technique,are deposited on a substrate via *** deposition pattern is dependent on the focused spot shape during laser *** intensity distribution of the Laguerre-Gaussian beam is *** with different inner diameters can be fabricated by varying the topological charge of the Laguerre-Gaussian *** equivalent inner diameters of the deposited rings with topological charges of 1,3,and 5 were 0.30,0.78,and 1.45μm,*** inner diameter of the deposited ring with a topological charge of 1 was smaller than the wavelength of the laser beam(532 nm).A tube was also fabricated with a topological charge of 3 by vertical displacement of the deposition *** deposition technology developed here using Laguerre-Gaussian beam will contribute to advancements in the fabrication of photonic and nano-fluidic devices.

关键词： Additive manufacturing Laguerre-Gaussian beam Laser trapping Maskless fabrication Electrophoretic deposition

Effects of Vertical Angle of Conical Punch on Stretch Flangeability of High Strength Steel

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Acta Metallurgica Sinica(English Letters) 2015年第12期28卷 1503-1509页

作者： Yasuhiro Ito Yoshiaki nakazawa Yukihisa Kuriyama Katsuyuki Suzuk Noriyuki Suzuki Nippon Steel and Sumitomo Metal Corporation The University of Tokyo

To clarify the effects of the vertical angle of a conical punch on stretch flangeability, hole expansion forming tests were conducted. Test results showed that the hole expansion ratio becomes larger as the vertical angle *** also showed that the fracture strain at the fracture location on the hole edge was constant and independent of the vertical angle. This is because the hole expansion ratio was controlled not only by the fracture strain, which is independent of the vertical angle, but also by deformation uniformity along the hole edge. From the result of numerical analyses, it was determined that deformation uniformity depends on the gradient of circumferential stress along the radius direction. When the vertical angle is sharp, the circumferential stress showed a steep decline and the deformation localization was suppressed. Consequently, the hole edge deformed more uniformly and the hole expansion ratio became larger. It is concluded that in order to improve stretch flangeability of high strength steel, it is important to uniformly deform the hole edge by applying a conical punch with a sharp vertical angle.

关键词： Formability Ductile fracture Finite element analysis Hole expansion test

Effect of roselle calyx extract on in vitro viability and biofilm formation ability of oral pathogenic bacteria

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Asian Pacific Journal of Tropical Medicine 2016年第2期9卷 115-120页

作者： Herastuti Sulistyani Mari Fujita Hiroshi Miyakawa Futoshi nakazawa Department of Oral Microbiology School of Dentistry Health Sciences University of Hokkaido

Objective: To investigate the effect of the roselle calyx extract(RCE)(Hibiscus sabdariffa L.) on the in vitro viability and biofilm formation ability of oral pathogenic bacteria. Methods:RCE was prepared by soaking roselle calyx powder with ethyl alcohol for 24 h at room temperature. After centrifugation, the extract was lyophilized. Then, the extract was dissolved in phosphate-buffered saline, the p H was adjusted, and the extract was aseptically filtered. We used Streptococcus mutans, Streptococcus sanguinis, Lactobacillus casei, Actinomyces naeslundii, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis and Prevotella intermedia in this study. The antibacterial activity of the RCE was determined by treating the cells of these bacteria with the extract for 10 or 20 min at room temperature. The minimum inhibitory concentration(MIC) and minimum bactericidal concentration was determined using the micro dilution method, and the effect of the RCE on the ability to form biofilm was determined using a polystyrene micro plate assay. In addition, we used the WST-1 assay to determine the cytotoxicity of the RCE on HGF, Ca9-22 and KB cells. Results: The RCE had antibacterial activity against oral bacteria used in this study. In particular, most significant antibacterial activity was observed against Fusobacterium nucleatum, Prevotella intermedia and Porphyromonas gingivalis. The MIC and minimum bactericidal concentration were 7.2 mg/m L–28.8 mg/m L and 14.4 to >57.6 mg/m L. The RCE had an inhibitory effect on biofilm formation at the MIC and sub-MIC levels. In addition, the RCE had low cytotoxic effects on HGF, Ca9-22 and KB cells. Conclusions: Thus, our results indicate that the RCE may be used for preventing oral diseases.

关键词： Oral bacteria Oral biofilm Oral cells Roselle calyx extract

Serum magnesium concentration in children with functional constipation treated with magnesium oxide

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World Journal of Gastroenterology 2011年第6期17卷 779-783页

作者： Maiko Tatsuki Reiko Miyazawa Takeshi Tomomasa Takashi Ishige Tomoko nakazawa Hirokazu Arakawa Department of Pediatrics Gunma University Graduate School of Medicine PAL Clinic 694 Tanakajima-machiIsesakiGunma 372-0802Japan

AIM:To determine whether hypermagnesemia recently reported in adult patients possibly develops in children with functional constipation taking daily magnesium ***:We enrolled 120 patients (57 male and 63 female) aged 1-14 years old (median:4.7 years) with functional constipation from 13 hospitals and two private *** patients fulfilled the Rome Ⅲ criteria for functional constipation and were treated with daily oral magnesium oxide for at least 1 *** median treatment dose was 600 (500-800) mg/*** were assessed by an interview and laboratory examination to determine possible *** magnesium concentration was also measured in sex-and agematched control subjects (n=38).RESULTS:In the constipation group,serum magnesium concentration [2.4 (2.3-2.5) mg/dL,median and interquartile range] was significantly greater than that of the control group [2.2 (2.0-2.2) mg/dL] (P < 0.001).The highest value was 3.2 mg/*** magnesium clearance was significantly increased in the constipation *** magnesium concentration in the constipation group decreased significantly with age (P < 0.01).There was no significant correlation between the serum level of magnesium and the duration of treatment with magnesium oxide or the daily *** of the patients had side effects associated with ***:Serum magnesium concentration increased significantly,but not critically,after daily treatment with magnesium oxide in constipated children with normal renal function.

关键词： Children Constipation Hypermagnesemia Magnesium oxide Renal dysfunction

Synthesis, structural characterization and magnetic property of nanocomposite materials: Intercalation compounds of FePS_3 with 1,10-phenanthroline or 2,2'-bipyridine

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Chinese Journal of Chemistry 2000年第4期18卷 510-515页

作者：陈兴国杨楚罗秦金贵 YAKUSHI Kyuya nakazawa Yasuhiro ICHIMURA Kenji Department of Chemistry Wuhan University Wuhan Hubei 430072 China Institute for Molecular Science Okazaki 444 Japan Department of Chemistry Kumamoto University Kumamoto 860 Japan

Two new intercalation compounds Fe0.90PS3(phen)0.41 (1) (phen stands for 1,10-phenanthroline including a part of 1, 10-phenanthroline H+) and Fe0.83PS3(bipy)0.34 (2) (bipy stands for 2,2'-bipyridine H+ ) were synthesized by the reaction of the layered FePS, with 1,10-phenanthroline or 2,2'-bipyridine in the presence of anilinium chloride. They were characterized by elemental analyses, powder X-ray diffraction (XRD), infrared spectroscopy. The lattice spacing of the intercalate was expanded by 0.90 nm for Fe0.90PS3(phen)0.41 and 0.57 nm for Fe0.83PS3(bipy)0.34 withrespect to the pristine FePS3, indicating that the ring plane of the guests is perpendicular to the layer of the host. The UV-vis absorption spectra of the filtrate in preparation of the intercalates indicate that 1, 10-phenanthroline or 2,2'-bipyridine also acts as a complexing agent to remove intralamellar Fe2+ ions into the solution during intercalation. The magnetic properties of 1 and 2 were studied.

关键词： Intercalation FePS3 1,10-phenanthroline 2,2'-bipyridine magnetic property