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Climatology of tropical cyclone tornadoes in China from 2006 to 2018

Science China Earth Sciences 2020年第1期63卷 37-51页

作者： Lanqiang BAI Zhiyong MENG kenta sueki Guixing CHEN Ruilin ZHOU School of Atmospheric Sciences and Guangdong Province Key Laboratory for Climate Change and Natural Disaster StudiesSun Yat-sen UniversityGuangzhou 510275China Laboratory for Climate and Ocean-Atmosphere Studies Department of Atmospheric and Oceanic SciencesSchool of PhysicsPeking UniversityBeijing 100871China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519000China RIKEN Center for Computational Science Kobe 650-0047Japan

We surveyed the occurrence of tropical cyclone(TC) tornadoes in China from 2006 to 2018. There were 64 cataloged TC tornadoes, with an average of five per year. About one-third of the landfalling TCs in China were tornadic. Consistent with previous studies, TC tornadoes preferentially formed in the afternoon shortly before and within about 36 h after landfall of the TCs. These tornadoes mainly occurred in coastal areas with relatively flat terrains. The maximum number of TC tornadoes occurred in Jiangsu and Guangdong provinces. Most of the TC tornadoes were spawned within 500 km of the TC center. Two notable characteristics were found:(1) TC tornadoes in China mainly occurred in the northeast quadrant(Earth-relative coordinates) rather than the right-front quadrant(TC motion-relative coordinates) of the parent TC circulation;and(2) most tornadoes were produced by TCs with a relatively weak intensity(tropical depressions/storms), in contrast with the United States where most tornadoes are associated with stronger TCs. Further analyses showed that TC tornadoes in China tend to be spawned in an environment with large low-level storm relative helicity and large convective available potential energy taking entrainment effects into account. TC tornadoes were particularly active in 2018, with 24 reported tornadoes accounting for 37.5% of the total surveyed samples. The first recorded tornado outbreak in the modern history of China occurred in the envelope of TC Yagi(2018), in which 11 tornadoes were reported in association with significant midlevel intrusions of dry air and the interaction of Yagi with an approaching midlatitude midlevel trough.

关键词： Tornadoes Tropical cyclones Historical statistics China

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中国热带气旋龙卷的气候统计特征(2006~2018)

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中国科学：地球科学 2020年第5期50卷 619-634页

作者：白兰强孟智勇 kenta sueki 陈桂兴周瑞琳中山大学大气科学学院广州510275 北京大学大气与海洋科学系北京100871 南方海洋科学与工程广东省实验室(珠海) 珠海519000 RIKEN Center for Computational Science Kobe 650-0047Japan

文章调查了2006至2018年中国热带气旋龙卷(简称TC龙卷)的发生情况.在这13年间,共有64次TC龙卷记录,平均每年发生约5次.约三分之一的登陆热带气旋至少有一个龙卷生成.这些TC龙卷主要发生在热带气旋临近登陆或登陆后36小时内的午后,集中... 详细信息

文章调查了2006至2018年中国热带气旋龙卷(简称TC龙卷)的发生情况.在这13年间,共有64次TC龙卷记录,平均每年发生约5次.约三分之一的登陆热带气旋至少有一个龙卷生成.这些TC龙卷主要发生在热带气旋临近登陆或登陆后36小时内的午后,集中于距离热带气旋中心500 km范围内.大多数TC龙卷位于地形相对平坦的沿海地区,其中江苏和广东是中国TC龙卷发生频次最大的两个省份.此外,文章还揭示了两个值得注意的特征:(1)中国的TC龙卷主要生成于TC中心的东北象限,而非TC移动方向的右前象限;(2)与美国相比,中国大多数TC龙卷生成于强度相对较弱的热带气旋(如热带低压、热带风暴).进一步分析表明,中国的TC龙卷倾向于在具有较大低层风暴相对螺旋度和较大对流有效位能(考虑夹卷效应)的环境中产生.中国2018年的TC龙卷尤其活跃,共有24次TC龙卷记录,占总样本数的37.5%.中国现代气象史上的首次龙卷爆发事件发生于台风摩羯(2018)中,至少有11个龙卷生成.此龙卷爆发事件发生于摩羯与中纬度中层槽的相互作用阶段,且伴随着较强的中高层干空气侵入过程.

关键词：龙卷热带气旋气候统计中国

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Stage IV malignant transformation of mature cystic teratoma palliatively treated with concurrent chemoradiotherapy:A case report

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World Journal of Clinical Cases 2025年第1期13卷 56-61页

作者： Saori Kondo Takashi Suzuki Kanato Yoshiike Sakura Yamanaka kenta Sonehara Hiroshi Nabeshima Osamu Oguchi Department of Obstetrics and Gynecology Saku Central Hospital Advanced Care CenterSaku City 385-0051NaganoJapan

BACKGROUND Malignant transformation(MT)of mature cystic teratoma(MCT)has a poor prognosis,especially in advanced *** chemoradiotherapy(CCRT)has an inhibitory effect on *** SUMMARY Herein,we present a case in which CCRT had a reduction effect preoperatively.A 73-year-old woman with pyelonephritis was referred to our *** tomography revealed right hydronephrosis and a 6-cm pelvic *** ultrasound-guided fine-needle biopsy(EUS-FNB)revealed squamous cell *** patient was diagnosed with MT of *** to her poor general con-dition and renal malfunction,we selected CCRT,expecting fewer adverse *** CCRT,her performance status improved,and the tumor size was reduced;surgery was *** months postoperatively,the patient developed dis-semination and lymph node *** chemotherapy was *** died 18 months after treatment *** EUS-FNB was useful in the diagnosis of MT of MCT;CCRT suppressed the disea-se and improved quality of life.

关键词： Mature cystic teratoma Malignant transformation Squamous cell carcinoma Concurrent chemoradiotherapy Endoscopic ultrasound-guided fine-needle biopsy Case report

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Regularizing fuel-optimal multi-impulse trajectories

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Astrodynamics 2024年第1期8卷 97-119页

作者： kenta Oshima Department of Mechanical Systems Engineering Hiroshima Institute of TechnologyHiroshima731-5193Japan

The regularization theory has successfully enabled the removal of gravitational singularities associated with celestial *** this study,regularizing techniques are merged into a multi-impulse trajectory design framework that requires delicate computations,particularly for a fuel minimization *** variables based on the Levi–Civita or Kustaanheimo–Stiefel transformations express instantaneous velocity changes in a gradient-based direct optimization *** formulation removes the adverse singularities associated with the null thrust impulses from the derivatives of an objective function in the fuel minimization *** favorite singularity-free property enables the accurate reduction of unnecessary impulses and the generation of necessary impulses for local optimal solutions in an automatic *** of fuel-optimal multi-impulse trajectories are presented,including novel transfer solutions between a near-rectilinear halo orbit and a distant retrograde orbit.

关键词： regularization trajectory optimization fuel minimization multi-impulse trajectory

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Novel synthesis of single-crystalline TbCu_(7)-type Sm-Fe powder by low-temperature reduction-diffusion process using molten salt

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Journal of Rare Earths 2022年第7期40卷 1126-1133页

作者： Shusuke Okada kenta Takagi Magnetic Powder Metallurgy Research Center National Institute of Advanced Industrial Science and Technology(AIST)2266-98 AnagahoraShimoshidami MoriyamaNagoya463-8560Japan

In this study,molten salt was used as a solvent for calcium(Ca)to let a reduction-diffusion(R-D)reaction occur below the melting point of Ca(1115 K),which is the lower limit temperature of the co nventional RD *** the R-D reaction is conducted below 923 K with LiCl molten salt,submicron-sized TbCu_(7)-type Sm-Fe powder is *** c/a ratio of the powder estimated by a synchrotron X-ray diffraction pattern is 0.8456,which is consistent with the Sm_(0.67)Fe_(5.667)(SmFe_(8.5))*** electron backscatter diffraction analysis reveals that single-crystalline TbCu_(7)-type SmFe_(8.5) powder was synthesized for the first time.

关键词： Reduction-diffusion TbCu_(7) Molten salt Permanent magnet Rare earths

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Isothermal γ →ε phase transformation behavior in a Co-Cr-Mo alloy depending on thermal history during electron beam powder-bed additive manufacturing

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Journal of Materials Science & Technology 2020年第15期47卷 162-170页

作者： Yufan Zhao Yuichiro Koizumi kenta Aoyagi kenta Yamanaka Akihiko Chiba Department of Materials Processing Graduate School of EngineeringTohoku UniversityAoba-yama 02Aoba-kuSendai980-8579Japan Institute for Materials Research Tohoku University2-1-J KatahiraAoba-kuSendai980-8577Japan

Powder bed fusion with electron beam(PBF-EB),allows Co-Cr-Mo(CCM) implants with patientcustomization to be fabricated with high quality and complex ***,the variability in the properties of PBF-EB-built CCM alloy,mainly due to the lack of understanding of the mechanisms that govern microstructural heterogeneity,brings limitations in extensive *** this study,the microstructural heterogeneity regarding the γ-fcc→ε-hcp phase transformation was *** phase transformation during PBF-EB was analyzed depending on the thermal history that was elucidated by the numerical *** revealed that isothermal γ→ε transformation occurred during the ***,the difference in γ/ε phase distribution was a result of the thermal history determining which method phase transformation was taking place,which can be influenced by the PBF-EB process *** the sample with a low energy input(Earea=2.6 J/mm2),the martensitic transformation was *** the building height increased from the bottom,the e phase fraction *** the other hand,in the sample with a higher energy input(Earea=4.4 J/mm2),the ε phase fo rmed via diffusional-massive transformation and only appea red in a short range of the lower part away from the bottom.

关键词： Powder bed fusion with electron beam Phase transformation Thermal history Numerical simulation

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Effects of metronomic sounds on a self-paced tapping task in budgerigars and humans

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Current Zoology 2019年第1期65卷 121-128页

作者： Yoshimasa Seki kenta Tomyta Department of Psychology Aichi University Machihatacho Toyohashi Aichi Japan

The origin of rhythmic synchronization or entrainment to a musical beat in animals has been widely discussed. Parrots are suitable animals to exami ne the relati on ship betwee n the capability of vocal learning and spontaneous rhythmic synchronization. In this study, budgerigars Melopsittacus undulatus learned to tap (peck) 2 keys alternately at a self-paced rate. Then, the metronomic sounds were played in the background during test sessions while the birds were performing the key pecking task, although they were not required to synchronize tap timing with the metronome. We found modest but significant effects of the metronome rhythms on the tap timing in some subjects. We also tested humans Homo sapiens using almost the same method. In contrast to the birds, a number of huma n subjects synchr on ized tap timing to the on set of the metronome without verbal or documented instructions. However, we failed to find an effect of the metronome on self-paced tap timing in some human subjects, although they were capable of rhythmic synchronization. This is the first report describing the effects of metronomic sounds on self-paced tapping in nonhuman vocal learners. This study introduces a new method that can be used in future research comparing birds that differ in vocal learning capacities, social structure, age, sex, hormonal status, and so on as part of exami nations of the evolutionary foun dati ons of beat processing.

关键词： opera nt con ditioning parrots rhythm synchronization vocal learning

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Low-temperature synthesis of Sm-Fe binary compounds by reduction-diffusion process using an eutectic salt solvent

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Rare Metals 2023年第5期42卷 1724-1731页

作者： Jungryang Kim Shusuke Okada kenta Takagi Magnetic Powder Metallurgy Research Center National Institute of Advanced Industrial Science and Technology(AIST)NagoyaAichi463-8560Japan

In this study,the temperature of the low-temperature reduction-diffusion(LTRD)process was successfully decreased to below 600℃by introducing LiClKCl eutectic molten salt with a low eutectic point(352℃)as a solvent for Ca ***,the Sm-Fe binary compounds,which were synthesizable at previously-unexplored low temperatures by the LTRD process using LiCl-KCl eutectic molten salt,were investigated,including whether a new metastable or ThMn_(12)-type Sm-Fe binary phase was *** Sm-Fe phase transitions of the SmFe binary compounds at a low temperature were identified,and it was found that MgCu_(2)-type Sm-Fe,PuNi_(3)-type SmFe and TbCu_(7)-type Sm-Fe phases were synthesized and stable at 400,500 and 550℃*** no new metastable Sm-Fe and ThMn_(12)-type Sm-Fe compounds were discovered in this study,this work can demonstrate that it is possible to synthesize the Sm-Fe phase at very low temperatures by the LTRD process for the first time.

关键词： Low-temperature synthesis Reductiondiffusion process Molten salts Hard magnet Sm-Fe compounds

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Aggregation-induced emission and thermally activated delayed fluorescence of 2,6-diaminobenzophenones

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Science China Chemistry 2018年第8期61卷 925-931页

作者： Masaki Shimizu Masaki Nakatani kenta Nishimura Faculty of Molecular Chemistry and Engineering Kyoto Institute of Technology

Exploration of novel organic luminophores that exhibit thermally activated delayed fluorescence(TADF) in the aggregated state is very crucial for advance of delayed luminescence-based applications such as time-gated bio-sensing and temperature *** report herein that synthesis, photophysical properties, molecular and crystal structures, and theoretical calculations of 2,6-bis(diarylamino)benzophenones. Absorption spectra in solution and calculations using density functional theory(DFT) method revealed that the optical excitation took place through intramolecular charge-transfer from one diarylamino moiety to an aroyl group. While the benzophenones did not luminesce in solution, the solids of the benzophenones emitted green light with moderate-to-good quantum yields. Thus, the benzophenones exhibit aggregation-induced emission. Based on the lifetime measurement, the green emission of the solids was found to include TADF. The emergence of the TADF is supported by the small energy gap between the excited singlet and triplet states, which was estimated by time-dependent DFT calculations. Thin films of poly(methyl methacrylate) doped by the benzophenones also showed green prompt and delayed fluorescence whose lifetimes were in the order of microseconds. Linear correlation between logarithm value of TADF lifetime and temperature was observed with the benzophenone in powder, suggesting that the benzophenones can serve as molecular thermometers workable under aqueous conditions.

关键词： donor-acceptor system delayed fluorescence temperature sensor

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Mechanism of reduction-diffusion reaction in Sm-Fe binary system at low temperature using molten salts

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Journal of Rare Earths 2024年第10期42卷 1889-1894页

作者： Jungryang Kim Shusuke Okada kenta Takagi Kimihiro Ozaki Innovative Functional Materials Research Institute National Institute of Advanced Industrial Science and Technology(AIST)4-205 SakurazakaMoriyamakuNagoya463-8560AichiJapan

In this study,the mechanism of the reduction-diffusion reaction in a Sm-Fe binary system at low temperature was studied to investigate the possibility of synthesis of a Fe-rich TbCu_(7)-type SmFe_(x)(x>9)by the low-temperature diffusion-reduction(LTRD)process using LiCl-KCl eutectic molten ***,the Sm-Fe phase transformation depending on the Sm-Fe composition,the LTRD temperature,and time was investigated,and it is found that the obtained metastable phase is only TbCu_(7)-type SmFe_(~8.5),which is not a Fe-rich *** Fe content does not change even after an expended LTRD process,and the metastable TbCu_(7)-type SmFe_(~8.5)tends to transform to the stable Sm_(2)Fe_(17)*** addition,it is found that the Sm-Fe phase starts to synthesize from the Sm-rich phase in the order of SmFe_(2),SmFe_(3),and SmFe_(8.5)as the LTRD temperature increases(when the time was 10 h)or the LTRD time increases(when the temperature was 550℃).Core-shell-like particles are observed in the case of a short LTRD time,and the core and the shell are Fe and the Sm-rich Sm-Fe phase,respectively,indicating that the Sm-rich phase begins to produce on the surface of the Fe *** is difficult to synthesize a Fe-rich TbCu_(7)-type SmFe_(x)(x>9)phase with the Sm-Fe binary system,suggesting that a different approach,such as addition of other elements,will be necessary.

关键词： Low-temperature synthesis Synthesis mechanism Reduction-diffusion process Molten salts Sm-Fe compounds Rare earths

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