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In situ observation of the phase transformation kinetics of bismuth during shock release

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Chinese Physics B 2024年第4期33卷 586-592页

作者：李江涛王倩男徐亮柳雷张航 Sota Takagi Kouhei Ichiyanagi Ryo Fukaya Shunsuke Nozawa 胡建波 Laboratory for Shock Wave and Detonation Physics Research Institute of Fluid PhysicsChina Academy of Engineering PhysicsMianyang 621900China State Key Laboratory for Environment-Friendly Energy Materials Southwest University of Science and TechnologyMianyang 621010China Japan Society for the Promotion of Science Tokyo102-0083Japan Institute of Materials Structure science High Energy Accelerator Research OrganizationIbaraki305-8572Japan

A time-resolved x-ray diffraction technique is employed to monitor the structural transformation of laser-shocked bismuth.Results reveal a retarded transformation from the shock-induced Bi-Ⅴphase to a metastable Bi-Ⅳphase during the shock release,instead of the thermodynamically stable Bi-Ⅲphase.The emergence of the metastable Bi-Ⅳphase is understood by the competitive interplay between two transformation pathways towards the Bi-Ⅳand Bi-Ⅲ,respectively.The former is more rapid than the latter because the Bi-Ⅴto B-Ⅳtransformation is driven by interaction between the closest atoms while the Bi-Ⅴto B-Ⅲtransformation requires interaction between the second-closest atoms.The nucleation time for the Bi-Ⅴto Bi-Ⅳtransformation is determined to be 5.1±0.9 ns according to a classical nucleation model.This observation demonstrates the importance of the formation of the transient metastable phases,which can change the phase transformation pathway in a dynamic process.

关键词： phase transformation time-resolved x-ray diffraction(XRD) bismuth metastable phase nonequilibrium phase diagram

Thermally activated delayed fluorescence carbazole-triazine dendrimer with bulky substituents

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Aggregate 2024年第1期5卷 236-243页

作者： Hiroki Ikebe Kohei Nakao Eri Hisamura Minori Furukori Yasuo Nakayama Takuya Hosokai Minlang Yang Guanting Liu Takuma Yasuda Ken Albrecht Interdisciplinary Graduate School of Engineering sciences Kyushu UniversityFukuokaJapan Institute for Materials Chemistry and Engineering Kyushu UniversityKasugaJapan Department of Pure and Applied Chemistry Graduate School of Science and TechnologyTokyo University of ScienceNodaChibaJapan National Metrology Institute of japan(NMIJ) National Institute of Advanced Industrial Science and Technology(AIST)TsukubaIbarakiJapan Institute for Advanced Study Kyushu UniversityNishi-kuFukuokaJapan

Carbazole-triazine dendrimers with a bulky terminal substituent were synthesized,and the thermally activated delayed fluorescence(TADF)property was investigated.Compared to unsubstituted carbazole dendrimers,dendrimers with bulky terminal substituents showed comparable to better photoluminescence quantum yields(PLQY)in neat films.Phenylfluorene(PF)-substituted dendrimers showed the highest PLQY of 81%,a smallΔEst of 0.06 eV,and the fastest reverse intersystem crossing(RISC)rate of∼1×10^(5 )s^(−1) compared to other dendrimers.Phosphorescence measurements of dendrimers and dendrons(fragments)indicate that the close proximity of the triplet energy of phenylfluorene-substituted carbazole dendrons(^(3)LE)to that of phenylfluorene-substituted dendrimers(^(1)CT,^(3)CT)contributes to RISC promotion and improves TADF efficiency.Terminal modification fine-tunes the energy level and suppresses intermolecular interactions,and this study provides a guideline for designing efficient solution-processable and non-doped TADF materials.

关键词： dendrimer OLED TADF 1 INTRODUCTION Thermally activated delayed fluorescence(TADF)materials which are inexpensive and highly efficient alternatives to fluorescent

Low-Energy Spin Excitations in Detwinned FeSe

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Chinese Physics Letters 2024年第6期41卷 112-118页

作者：刘瑞鲜 Mitsutaka Nakamura Kazuya Kamazawa 鲁兴业 Center for Advanced Quantum Studies School of Physics and AstronomyBeijing Normal UniversityBeijing 100875China J-PARC Center Japan Atomic Energy Agency(JAEA)TokaiIbaraki 319-1195Japan Research Center for Neutron science and Technology Comprehensive Research Organization for Science and SocietyTokaiIbaraki 319-1106Japan

Antiferromagnetic spin fluctuation is regarded as the leading driving force for electron pairing in high-Tc superconductors.In iron-based superconductors,spin excitations at low energy range,especially the spin-resonance mode at ER~5kBTc,are important for understanding the superconductivity.Here,we use inelastic neutron scattering(INS)to investigate the symmetry and in-plane wave-vector dependence of low-energy spin excitations in uniaxial-strain detwinned Fe Se.The low-energy spin excitations(E<10 meV)appear mainly at Q=(±1,0)in the superconducting state(T9K)and the nematic state(T90 K),confirming the constant C_(2)rotational symmetry and ruling out the C_(4)mode at E≈3 meV reported in a prior INS study.Moreover,our results reveal an isotropic spin resonance in the superconducting state,which is consistent with the s±wave pairing symmetry.At slightly higher energy,low-energy spin excitations become highly anisotropic.The full width at half maximum of spin excitations is elongated along the transverse direction.The Q-space isotropic spin resonance and highly anisotropic low-energy spin excitations could arise from dyz intra-orbital selective Fermi surface nesting between the hole pocket aroundΓpoint and the electron pockets centered at MX point.

关键词： excitation symmetry slightly

Cisplatin-induced activation of TGF-βsignaling contributes to drug resistance

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Oncology Research 2024年第1期32卷 139-150页

作者： SAYAKA IMATSUJI YUKIKO UJIE HIROYUKI ODAKE MASAYA IMOTO SUSUMU ITOH ETSU TASHIRO Department of Biosciences and Informatics Faculty of Science and TechnologyKeio UniversityYokohama223-8522Japan Department of Neurology Juntendo University Graduate School of MedicineTokyo113-8421Japan Laboratory of Biochemistry Showa Pharmaceutical UniversityTokyo194-8543Japan

Growing evidence suggests an association between epithelial-mesenchymal transition(EMT),a hallmark of tumor malignancy,and chemoresistance to a number of anti-cancer drugs.However,the mechanism of EMT induction in the process of acquiring anti-cancer drug resistance remains unclear.To address this issue,we obtained a number of cisplatin-resistant clones from LoVo cells and found that almost all of them lost cell-cell contacts.In these clones,the epithelial marker E-cadherin was downregulated,whereas the mesenchymal marker N-cadherin was upregulated.Moreover,the expression of EMT-related transcription factors,including Slug,was elevated.On the other hand,the upregulation of other mesenchymal marker Vimentin was weak,suggesting that the mesenchymal-like phenotypic changes occurred in these cisplatin-resistant clones.These mesenchymal-like features of cisplatin-resistant clones were partially reversed to parental epithelial-like features by treatment with transforming growth factor-β(TGF-β)receptor kinase inhibitors,indicating that TGF-βsignaling is involved in cisplatin-induced the mesenchymallike phenotypic changes.Moreover,cisplatin was observed to enhance the secretion of TGF-βinto the culture media without influencing TGF-βgene transcription.These results suggest that cisplatin may induce the mesenchymal-like phenotypic changes by enhancing TGF-βsecretion,ultimately resulting in drug resistance.

关键词： Cisplatin EMT Chemo-resistance TGF-β

Whether to Abolish or Introduce Dual Regulation as Trade and Environmental Policy?

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China & World Economy 2024年第1期32卷 57-95页

作者： Yoshihiro Hamaguchi Department of Economics Faculty of Economics and Business AdministrationKyoto University of Advanced ScienceJapan

China,which has already introduced an environmental tax in an effort to decarbonize,has recently begun emissions trading and is using two environmental policies in tandem,but there are concerns about the impact on growth and trade.Trade and environmental policies affect firms'entry and exit,resulting in changes in aggregate productivity and pollution emissions.This study compares the impacts of single regulation and dual regulation on welfare,using a research-and-development based growth model with heterogeneous firms.Under single regulation,the cleansing effect of trade liberalization could be undermined.Under dual regulation,trade liberalization decreases pollution and improves average productivity whereas decreasing total permits reduces pollution.From the perspective of improving welfare it is desirable to choose dual regulation because trade liberalization can reduce total pollution emissions via the cleansing effect of trade liberalization.

关键词： dual regulation heterogeneous firm Porter hypothesis research and development difficulty trade liberalization

Twisted fiber microfluidics:a cutting-edge approach to 3D spiral devices

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Microsystems & Nanoengineering 2024年第1期10卷 193-202页

作者： Shunsuke Kato Daniel W.Carlson Amy Q.Shen Yuanyuan Guo Department of Electrical Information and Physics EngineeringSchool of EngineeringTohoku UniversityAoba-kuSendai 980-8579 MiyagiJapan Micro/Bio/Nanofluidics Unit Okinawa Institute of Science and TechnologyOnnaKunigami-gun 904-0495 OkinawaJapan Frontier Research Institute for Interdisciplinary sciences(FRIS) Tohoku UniversityAoba-kuSendai 980-0845 MiyagiJapan Graduate School of Biomedical Engineering Tohoku UniversityAoba-kuSendai 980-8579 MiyagiJapan Department of Physiology Graduate School of MedicineTohoku UniversityAoba-kuSendai 980-8575 MiyagiJapan

The development of 3D spiral microfluidics has opened new avenues for leveraging inertial focusing to analyze small fluid volumes,thereby advancing research across chemical,physical,and biological disciplines.While traditional straight microchannels rely solely on inertial lift forces,the novel spiral geometry generates Dean drag forces,eliminating the necessity for external fields in fluid manipulation.Nevertheless,fabricating 3D spiral microfluidics remains a labor-intensive and costly endeavor,hindering its widespread adoption.Moreover,conventional lithographic methods primarily yield 2D planar devices,thereby limiting the selection of materials and geometrical configurations.To address these challenges,this work introduces a streamlined fabrication method for 3D spiral microfluidic devices,employing rotational force within a miniaturized thermal drawing process,termed as mini-rTDP.This innovation allows for rapid prototyping of twisted fiber-based microfluidics featuring versatility in material selection and heightened geometric intricacy.To validate the performance of these devices,we combined computational modeling with microtomographic particle image velocimetry(uTPiM)to comprehensively characterize the 3D flow dynamics.Our results corroborate the presence of a steady secondary flow,underscoring the effectiveness of our approach.Our 3D spiral microfluidics platform paves the way for exploring intricate microflow dynamics,with promising applications in areas such as drug delivery,diagnostics,and lab-on-a-chip systems.

关键词： thereby straight twisted

Monogenic gene therapy for glaucoma and optic nerve injury

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Neural Regeneration Research 2025年第3期20卷 815-816页

作者： Chikako Harada Xiaoli Guo Takayuki Harada Visual Research Project Tokyo Metropolitan Institute of Medical ScienceTokyoJapan

The prevalence of glaucoma, the second leading cause of global blindness, is increasing due to aging populations. In glaucoma, degeneration of the optic nerve and retinal ganglion cells(RGCs) causes visual field defec... 详细信息

关键词： visual glaucoma degeneration

Classification of complete 3-dimensional self-shrinkers in the Euclidean space R^(4)

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science China Mathematics 2024年第4期67卷 873-882页

作者： Qing-Ming Cheng Zhi Li Guoxin Wei Department of Applied Mathematics Faculty of ScienceFukuoka UniversityFukuoka 814-0180Japan College of Mathematics and Information science Henan Normal UniversityXinxiang 453007China School of Mathematical sciences South China Normal UniversityGuangzhou 510631China

In this paper,we completely classify 3-dimensional complete self-shrinkers with the constant norm S of the second fundamental form and the constant f3in the Euclidean space R^(4),where hij’s are components of the sec... 详细信息

关键词： mean curvature ow self-shrinker the generalized maximum principle

Computer-controlled ultra high voltage amplifier for dielectric elastomer actuators

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Biomimetic Intelligence & Robotics 2024年第1期4卷 14-23页

作者： Ardi Wiranata Zebing Mao Yu Kuwajima Yuya Yamaguchi Muhammad Akhsin Muflikhun Hiroki Shigemune Naoki Hosoya Shingo Maeda Department of Mechanical and Industrial Engineering University of Gadjah MadaYogyakarta 55281Indonesia Department of Mechanical Engineering Tokyo Institute of TechnologyTokyo 152-8550Japan Department of Engineering and science Shibaura Institute of TechnologyTokyo 135-8548Japan Department of Electrical Engineering Shibaura Institute of TechnologyTokyo 135-8548Japan Department of Engineering science and Mechanics Shibaura Institute of TechnologyTokyo 135-8548Japan Living Systems Materialogy(LiSM)Research Group International Research Frontiers Initiative(IRFI)Tokyo Institute of TechnologyYokohama 226-8501Japan

Soft robotics is a breakthrough technology to support human-robot interactions.The soft structure of a soft robot can increase safety during human and robot interactions.One of the promising soft actuators for soft robotics is dielectric elastomer actuators(DEAs).DEAs can operate silently and have an excellent energy density.The simple structure of DEAs leads to the easy fabrication of soft actuators.The simplicity combined with silent operation and high energy density make DEAs interesting for soft robotics researchers.DEAs actuation follows the Maxwell-pressure principle.The pressure produced in the DEAs actuation depends much on the voltage applied.Common DEAs requires high voltage to gain an actuation.Since the power consumption of DEAs is in the milli-Watt range,the current needed to operate the DEAs can be neglected.Several commercially available DC-DC converters can convert the volt range to the kV range.In order to get a voltage in the 2-3 kV range,the reliable DC-DC converter can be pricy for each device.This problem hinders the education of soft actuators,especially for a newcomer laboratory that works in soft electric actuators.This paper introduces an entirely do-it-yourself(DIY)Ultrahigh voltage amplifier(UHV-Amp)for education in soft robotics.UHV-Amp can amplify 12 V to at a maximum of 4 kV DC.As a demonstration,we used this UHV-Amp to test a single layer of powdered-based DEAs.The strategy to build this educational type UHV-Amp was utilizing a Cockcroft-Walton circuit structure to amplify the voltage range to the kV range.In its current state,the UHV-Amp has the potential to achieve approximately 4 kV.We created a simple platform to control the UHV-Amp from a personal computer.In near future,we expect this easy control of the UHV-Amp can contribute to the education of soft electric actuators.

关键词： Dielectric elastomer actuators Electric amplifier Soft actuators Soft robotics Soft actuator education