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Non-epitaxial growth of highly oriented Transition metal dichalcogenides with density-controlled twin boundaries

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The Innovation 2023年第6期4卷 30-37页

作者： Juntong Zhu Zhili Hu Shasha Guo Ruichun Luo Maolin Yu Ang Li Jingbo Pang Minmin Xue Stephen J.Pennycook Zheng Li Zhuhua Zhang Wu Zhou School of Physical Sciences CAS Key Laboratory of Vacuum PhysicsUniversity of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Mechanics and Control for Aerospace Structures Key Laboratory for Itelligent Nano Materials and Devices of Ministry of Educationand Institute for Frontier ScienceNanjing University of Aeronautics and AstronauticsNanjing 210013China School of Materials Science and Engineering Nanyang Technological UniversitySingapore 639798Singapore Environmental Chemistry and Materials Centre Nanyang Environment and Water Research InstituteNanyang Technological UniversitySingapore 637141Singapore

Twin boundaries(TBs)in Transition metal dichalcogenides(TMDs)constitute distinctive one dimensional electronic systems,exhibiting intriguing physical and chemical properties that have garnered significant attention in the fields of quantum physics and electrocatalysis.However,the controlled manipula-tion of TBs in terms of density and specific atomic configurations remains a fomidable challenge.In this study,we present a non-epitaxial growth approach that enables the controlled and large scale fabrication of homoge-neous catalytically active TBs in monolayer TMDs on arbitrary substrates.Notably,the density achieved using this strategy is six times higher than that observed in convention chemical vapor deposition(CVD)-grown sam-ples.Through rigorous experimental analysis and multigrain Wulff construc tion simulations,we elucidate theroleof regulating themetal source diffusion process,which serves as the key factor for inducing the self-oriented growth ofTMD grains and the formation of unified TBs.Furthermore,we demonstrate that this novel growth mode can be readily incorporated into the conventional CVD growth method by making a simple modification of the growth tempera-ture profle,thereby offering a universal approach for engineering of grain boundaries in two-dimensional materials.

关键词： grain Transition tempera

Crystalline-amorphization-recrystallization structural Transition and emergent superconductivity in van der Waals semiconductor SiP under compression

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 115-122页

作者： Chunhua Chen Zhenyu Ding Yonghui Zhou Yifang Yuan Nixian Qian Jing Wang Shuyang Wang Ying Zhou Chao An Min Zhang Xuliang Chen Xiaoping Yang Mingliang Tian Zhaorong Yang Anhui Key Laboratory of Low-Energy Quantum Materials and Devices High Magnetic Field LaboratoryHFIPSChinese Academy of SciencesHefei 230031China Science Island Branch of Graduate School University of Science and Technology of ChinaHefei 230026China Key Laboratory of Material Physics Ministry of EducationSchool of Physics and MicroelectronicsZhengzhou UniversityHefei 230601China Institutes of Physical Science and Information Technology Anhui UniversityZhengzhou 450001China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

van der Waals(vdW)semiconductors have gained significant attention due to their unique physical properties and promising applications,which are embedded within distinct crystallographic symmetries.Here,we report a pressure-induced crystallineamorphization-recrystallization Transition under compression in binary vdW semiconductor SiP.Upon compression to 52 GPa,bulk SiP undergoes a consecutive phase Transition from pristine crystalline to amorphous phase,ultimately to recrystallized phase.By employing synchrotron X-ray diffraction experiments in conjunction with high-pressure crystal structure searching techniques,we reveal that the recrystallized Si P hosts a tetragonal structure(space group I4mm)and further transforms partially into a cubic phase(space group Fm3m).Consistently,electrical transport and alternating-current magnetic susceptibility measurements indicate the presence of three superconducting phases,which are embedded in separate crystallographic symmetries—the amorphous,tetragonal,and cubic structures.Furthermore,a high superconducting Transition temperature of 12.3 K is observed in its recovered tetragonal phase during decompression.Our findings uncover a novel phase evolution path and elucidate a pressure-engineered structure-property relationship in vdW semiconductor SiP.These results not only offer a new platform to explore the transformation between different structures and functionalities,but also provide new opportunities for the design and exploration of advanced devices based on vdW materials.

关键词： recrystallization Transition amorphous

Transition-metal-free synthesis of 4-aminoisoquinolin-1(2H)-ones via a tandem reactionof arynes and oxazoles

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Organic Chemistry Frontiers 2022年第6期9卷 1550-1555页

作者： Shaojun Liu Pei Xie Leifang Wu Jixing Zhao Zhihua Cai Lin He Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan School of Chemistry and Chemical EngineeringShihezi UniversityXinjiang Uygur Autonomous Region 832000People’s Republic of China Analysis and Testing Center of Shihezi University Xinjiang Uygur Autonomous Region832000China

A facile and Transition-metal-free method for the synthesis of 4-amino isoquinolin-1(2H)-ones has beendeveloped. Arynes react with 4,5-disubstituted oxazoles through a tandem Diels–Alder reaction/dehydrogenation–aromatization/tautamerization process to produce 4-amino isoquinolin-1(2H)-ones in moderate to excellent yields. The reaction can be easily scaled up and the product can be transformed to isoquinoline derivatives efficiently.

关键词： synthesis Transition

Numerical Analysis of Heat Transfer Characteristics to Supercritical CO_(2) in a Vertical Mini-Channel:Transition and Pseudo-Boiling

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Journal of Thermal Science 2024年第1期33卷 101-113页

作者： YUAN Baoqiang WANG Wei XIN Gongming DU Wenjing School of Energy and Power Engineering Shandong UniversityJi'nan 250061China

Large eddy simulations have been conducted to study upward Transitional flows and heat transfer characteristics of supercritical CO_(2) in a vertical mini-channel.The numerical simulation was carried out on a modified buoyantPimpleFOAM solver in OpenFOAM 7,and was verified using experiment data.Numerical results indicate that increasing the Grashof numbers can reduce the flow stability and make the flow Transition earlier.There are four stages of heat transfer in the Transition process,i.e.,weakened,improved,recovered and normal heat transfer.These heat transfer phenomena in the Transition process were explained from three perspectives:thermal boundary layer theory,turbulent transport and pseudo-boiling theory.Heat transfer enhancement during Transition is related to the transport of supercritical molecular clusters,and these molecular clusters are regarded as pseudo-bubbles in pseudo-boiling theory.The flow pattern of the pseudo-phases in the dia-Widom process contains single-phase flow,steady pseudo-film flow,unsteady pseudo-film flow,partial pseudo-bubbles flow and flocculent pseudo-film flow.Pseudo-bubbles have similar behaviors to subcritical bubbles,i.e.,break-up,deformation,condensation and coalescence.Relevant researches in this work are favorable for understanding the heat transfer mechanism of supercritical fluids during flow Transition.

关键词： supercritical heat transfer large eddy simulation Transition pseudo-boiling

Transition-metal-free hydroamination/defluorination/cyclization of perfluoroalkyl alkynes with amidines

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Organic Chemistry Frontiers 2022年第1期9卷 109-116页

作者： Li-Wen Sun Zi-Lun Yu Xin-Long Luo Mengtao Ma Zhi-Liang Shen Xue-Qiang Chu Institute of Advanced Synthesis School of Chemistry and Molecular EngineeringNanjing Tech UniversityNanjing 211816China Department of Chemistry and Materials Science College of ScienceNanjing Forestry UniversityNanjing 210037China

An efficient defluorinative net-[3+3]-cyclization strategy for the construction of perfluoroalkyl-substituted pyrimidine derivatives by using a series of perfluoroalkyl alkynes and amidines as starting materials was developed.The present reaction proceeded successfully under Transition-metal-free conditions to form two new C–N bonds and a new heterocyclic ring through a sequence of hydroamination,defluorination,and annulation.The desired pyrimidines could be obtained with good functional group tolerance and moderate to good yields.Moreover,the distinctive fluorine effects of perfluoroalkyl substituents are vital for tuning the reactivity of alkynes for the anticipated defluorinative annulation.The pendantπsystem would lower associated bond dissociation energy significantly compared to that of a nonactivated C(sp^(3))–F bond.

关键词： cyclization pyrimidine Transition

Time-resolved visualization of coherent structures during supersonic boundary layer Transition

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Chinese Journal of Aeronautics 2023年第4期36卷 190-200页

作者： Lin HE Xiaoge LU Junhao HAN Zhengbang WU Shihe YI College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China

The coherent structures arising during flat-plate boundary layer Transition at Mach num-ber 3.4 are investigated using a custom-built hyper-rate imaging system.The evolution of transi-tional structures is investigated in the Eulerian and Lagrangian reference frames.The upstream evolution of Transition is dominated by the generation of new hairpin structures,while the interac-tion among multiple structural types dominates the evolution downstream.The breakdown of the existing structure,which may be caused by interactions among multiple types of structures with sim-ilar scales,is also visualized.

关键词： Coherent structures Flow visualization Supersonic boundary layer Time-resolved Transition

Recent applications in dielectric barrier discharge and radio frequency plasmas‐engineered Transition metal electrocatalysts for water splitting

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High Voltage 2023年第6期8卷 1115-1131页

作者： Guangliang Chen Bin He Yuxin Wang Pengchen He Liguang Dou Renwu Zhou Dongliang Chen Tao Shao Department of Materials Engineering Huzhou UniversityHuzhouChina School of Materials Science and Engineering Zhejiang Sci‐Tech UniversityHangzhouChina Beijing International S&T Cooperation Base for Plasma Science and Energy Conversion Institute of Electrical EngineeringChinese Academy of SciencesBeijingChina State Key Laboratory of Electrical Insulation and Power Equipment Centre for Plasma BiomedicineXi'an Jiaotong UniversityXi'anChina State Key Laboratory of Silicon and Advanced Semiconductor Materials School of Materials Science and EngineeringZhejiang UniversityHangzhouChina

Hydrogen generated by water electrolysis is considered as one of the most promising protocols to partly replace the roles of traditional fossil fuels.However,high‐performance electrocatalyst satisfied with the industrial requirement still faces significant challenges.Low‐temperature plasma contains numerous high‐energy ions,electrons and other reactive species,which can provide a highly reactive environment for tuning the physio‐chemical structures of catalysts through plasma milling,etching,doping and/or deposi-tion.It is well‐known that high‐temperature micro‐filaments contained in plasmas can cause some special modifications of the catalyst surface,thus effectively adjusting the physio‐chemical structure of latterly engineered compounds.Therefore,low‐temperature plasma technologies,especially the dielectric barrier discharge(DBD)and radio frequency(RF)plasmas,can be considered as a green and sustainable strategy for engineering high‐performance electrocatalysts for water splitting(hydrogen evolution reaction[HER];oxygen evolution reaction[OER]).Herein,recent progress of DBD and RF plasmas for fabricating and modifying Transition metal‐based electrocatalysts(e.***.sulphide,phos-phide,selenide,oxide,hydroxide)for hydrogen evolution reaction or OER is compre-hensively reviewed,and the role of plasma is also discussed.

关键词： splitting dielectric Transition

A Hybrid Territorial Aquatic Bionic Soft Robot with Controllable Transition Capability

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Journal of Bionic Engineering 2023年第2期20卷 568-583页

作者： Qingzhong Li Fukang Zhang Zeying Jing Fujie Yu Yuan Chen Department of Mechatronics and Information Engineering Shandong University at WeihaiWeihai264209China

In this paper,a bionic mantis shrimp amphibious soft robot based on a dielectric elastomer is proposed to realize highly adaptive underwater multimodal motion.Under the action of an independent actuator,it is not only able to complete forward/backwards motion on land but also has the ability of cyclically controllable Transition motion from land to water surface,from water surface to water bottom and from water bottom to land.The fastest speed of the soft robot on land is 170 mm/s,and it can crawl while carrying up to 4.6 times its own weight.The maximum speeds on the water surface and the water bottom are 30 mm/s and 14.4 mm/s,respectively.Furthermore,the soft robot can climb from the water bottom with a 9°slope Transition to land.Compared with other similar soft robots,this soft robot has outstanding advantages,such as agile speed,large load-carrying capacity,strong body flexibility,multiple motion modes and strong underwater adaptability.Finally,nonlinear motion models of land crawling and water swimming are proposed to improve the environmental adaptability under multiple modalities,and the correctness of the theoretical model is verified by experiments.

关键词： Transition Amphibious soft robot Dielectric elastomers Bionic mantis shrimp soft robot

Capturing Transition and non-Transition flows with a new shear stress transport model

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Chinese Journal of Aeronautics 2023年第3期36卷 121-136页

作者： Md Mizanur RAHMAN School of Mechanical Engineering Hangzhou Dianzi UniversityHangzhou 310018China

A new Shear Stress Transport(SST)k-ω model is devised to integrate salient features of both the non-Transitional SST k-ω model and correlation-based γ-Re_(θ) Transition model.An exceptionally simplified approach is applied to extend the New SST(NSST)model capabilities toward Transition/non-Transition predictions.Bradshaw’s stress-intensity factor R_(b)=|-uv|/k can be parameterized with the wall-distance dependent Reynolds number Re_(y)=√ky/v;however,as the Re_(y)is replaced by a“flow-structure-adaptive”parameter R_(μ)=v_(T)/v,the resulting R_(b)is capable of capturing various Transition phenomena naturally.The prospective stress-intensity parameter R_(b)=R_(b)(Re_(y),R_(μ))is incorporated in the constitutive relations for eddy-viscosity v_(T) and production term P_(k).The proposed formulation is intrinsically plausible,having a dramatic impact on the prediction of bypass,separation-induced and natural Transitions together with non-Transitional flows.An extra viscous-production term P_(k)^(lim) is added with the k-equation to ensure proper generation of k at the viscous sublayer when computing separation-induced Transition over a Low-Reynolds Number(LRN)airfoil.Results demonstrate that the NSST k-ω model maintains an excellent consistency with both SST k-ω and γ-Re_(θ) models.

关键词： γ-Re_(θ)model Non-Transition Stress-intensity parameter SST model Transition