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Modifying Quantum Well States of Pb Thin Films via Interface Engineering

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Chinese Physics Letters 2010年第6期27卷 160-163页

作者： FU Ying-Shuang JI Shuai-Hua ZHANG Tong CHEN Xi JIA Jin-Feng xuE Qi-Kun ma xu-cun Institute of Physics Chinese Academy of Sciences Beijing 100190 Department of Physics Tsinghua University Beijing 100084

We demonstrate the importance of interface modification on improving electron confinement by preparing Pb quantum islands on Si（111） substrates with two different surface reconstructions, i.e., Si（111）-7 ×7 and Si（111）- Root3×Root3-Pb （hereafter, 7 ×7 and R3）. Characterization with scanning tunneling microscopy/spectroscopy shows that growing Pb films directly on a 7 × 7 surface will generate many interface defects, which makes the lifetime of quantum well states （QWSs） strongly dependent on surface locations. On the other hand, QWSs in Pb films on an R3 surface are well defined with small variations in linewidth on different surface locations and are much sharper than those on the 7 × 7 surface. We show that the enhancement in quantum confinement is primarily due to the reduced electron-defect scattering at the interface.

关键词： QUANTUM wells ENERGY levels (Quantum mechanics) METALLIC films INTERFACES (Physical sciences) QUARK confinement SILICA SCANNING tunneling microscopy SCATTERING (Physics)

Extreme precipitation detection ability of four high-resolution precipitation product datasets in hilly area:a case study in Nepal

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Advances in Climate Change Research 2024年第3期15卷 390-405页

作者： Sunil Subba Yao-Ming ma Wei-Qiang ma cun-Bo Han Land-Atmosphere Interaction and its Climatic Effects Group State Key Laboratory of Tibetan Plateau Earth SystemEnvironment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China College of Atmospheric Science Lanzhou UniversityLanzhou 730000China National Observation and Research Station for Qomolongma Special Atmospheric Processes and Environmental Changes Dingri 858200China Kathmandu Center of Research and Education Chinese Academy of SciencesBeijing 100101China China-Pakistan Joint Research Center on Earth Sciences Chinese Academy of SciencesIslamabad 45320Pakista

Given Nepal's vulnerability to extreme precipitation(EP),it is imperative to conduct a comprehensive analysis to comprehend the historical trends of such ***,acquiring precise precipitation data for EP remains challenging in mountainous countries like Nepal owing to the scarcity of densely gauged *** limitation impedes the dissemination of knowledge pertaining to EP variability events in *** current research on this topic is deficient for two main reasons:1)there is a lack of studies leveraging recently released high-resolution precipitation products to identify their EP detection capabilities,which further hinders the usability of those products in data-scarce regions like Nepal,and 2)most studies have focused on the characterisation of EP events in Nepal rather than their spatial and temporal *** address these issues,this study evaluated the EP detection capabilities of four high-resolution precipitation product datasets(PPDs)across Nepal from 1985 to *** datasets include the ERA5 Land reanalysis data,satellite-based precipitation data(PERSIANN_CCS_CDR and CHIRPS_V2.0)and a merged dataset(TPHiPr).We used various statistical and categorical indices to assess their ability to capture the spatial and temporal variability of EP *** annual EP events were characterised by 11 indices divided into frequency and intensity *** TPHiPr merged dataset offered a robust depiction of monthly precipitation estimates,achieving the highest critical success index,accuracy,probability of detection and a low false alarm ratio for daily precipitation detection of 0.1 mm in ***,the PERSIANN_CCS_CDR dataset exhibited poor *** PPDs showed increasing trends in EP ***,the TPHiPr dataset showcased those trends with fewer errors and stronger correlations for many frequency(R10mm,R20mm and R25mm)and intensity(RX1day,RX5day,PRCPTOT and R99p)*** results indicate that TPHiPr outperformed ot

关键词： Extreme precipitation Precipitation product Nepal TPHiPr ERA5 land PERSIANN_CCS_CDR CHIRPS_V2.0

Effect of Cryogenic Treatment on Microstructure and Tribological Property Evolution of Electron Beam Melted Ti6Al4V

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Journal of Wuhan University of Technology(materials Science) 2024年第4期39卷 1010-1017页

作者：黄西娜 ma Xiaowen xu Tianyi School of Mechanical and Electrical Engineering China University of Mining and Technology-BeijingBeijing 100083China School of Engineering and Technology China University of GeosciencesBeijing 100083China

Cryogenic treatment was used to improve the tribological properties of Ti6Al4V artificial hip joint *** treatment at-196℃with different holding time were carried out on Ti6Al4V specimens fabricated using electron beam melting(EBM),and their microstructure and tribological properties evolution were systematically analyzed by scanning electron microscopy(SEM),vickers hardness,and wear *** experimental results show that the as-fabricated specimen consists of lamellarαphase andβcolumnar ***,the thickness of lamellarαphase decreased after cryogenic *** addition,it can be found that the fineαphase was precipitated and dispersed between the lamellarαphase with the holding time *** hardness shows a trend of first increasing and then *** wear rate of the specimen cryogenic treated for 24 h is the minimum and the average friction coefficient is 0.50,which is reduced by 14.61%compared with the *** wear mechanism of the as-fabricated specimen is severe exfoliation,adhesive,abrasive,and slight fatigue ***,the specimen cryogenic treated for 24 h shows slight adhesive and abrasive *** can be concluded that it is feasibility of utilizing cryogenic treatment to reduce the wear of EBMed Ti6Al4V.

关键词： electron beam melting(EBM) cryogenic treatment microstructure vickers hardness tribological property

Atomic-Scale Study of Ge-Induced Incommensurate Phases on Si（111）

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Chinese Physics Letters 2010年第2期27卷 228-231页

作者：吴蕊王立莉张翼马旭村贾金锋薛其坤 Institute of Physics Chinese Academy of Sciences Beijing 100190 Department of Physics Tsinghua University Beijing 100084

Two Ge-induced incommensurate phases, γ and β, on Si（111） are observed and studied by {／it in situ} scanning tunneling microscopy. The γ phase consists of aligned triangular domains whose stacking sequence is faulted with respect to the Si（111）-1×1 surface. The β phase consists of two kinds of triangular domains whose stacking sequences are faulted and unfaulted with respect to the Si（111）-1×1 surface, respectively. In the β phase, two types of domain walls, zigzag＇＇ and face-to-face＇＇, form to release the strain. The triangular domains all exhibit a quasi-1×1 hexagonal close-packed structure. By studying the structural evolution from magic clusters to incommensurate structures, the structure models for γ and β phases are proposed.

关键词： Silicon Timing Time Stacking

A Review on Vibration Control of Multiple Cylinders Subjected to FlowInduced Vibrations

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China Ocean Engineering 2024年第2期38卷 183-197页

作者： xu Wan-hai ma Ye-xuan State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation Tianjin UniversityTianjin 300350China Institute of Mechanics Chinese Academy of SciencesBeijing 100190China

The fatigue damage caused by flow-induced vibration(FIV)is one of the major concerns for multiple cylindrical structures in many engineering *** FIV suppression is of great importance for the security of many cylindrical *** active and passive control methods have been employed for the vibration suppression of an isolated cylinder undergoing vortex-induced vibrations(VIV).The FIV suppression methods are mainly extended to the multiple cylinders from the vibration control of the isolated *** to the mutual interference between the multiple cylinders,the FIV mechanism is more complex than the VIV mechanism,which makes a great challenge for the FIV *** efforts have been devoted to vibration suppression of multiple cylinder systems undergoing FIV over the past two *** control methods,such as helical strakes,splitter plates,control rods and flexible sheets,are not always effective,depending on many influence factors,such as the spacing ratio,the arrangement geometrical shape,the flow velocity and the parameters of the vibration control *** FIV response,hydrodynamic features and wake patterns of the multiple cylinders equipped with vibration control devices are reviewed and *** FIV suppression efficiency of the vibration control methods are analyzed and compared considering different influence *** research on the FIV suppression of multiple cylinders is suggested to provide insight for the development of FIV control methods and promote engineering applications of FIV control methods.

关键词： flow-induced vibration vibration control multiple cylinders tandem side-by-side staggered

Hydrologic Response to Future Climate Change in the Dulong-Irra-waddy River Basin Based on Coupled Model Intercomparison Project 6

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Chinese Geographical Science 2024年第2期34卷 294-310页

作者： xu Ziyue ma Kai YUAN xu HE Daming Institute of International Rivers and Eco-security Yunnan UniversityKunming 650500China Yunnan Key Laboratory of International Rivers and Transboundary Eco-security Kunming 650500China

Within the context of the Belt and Road Initiative(BRI)and the China-Myanmar Economic Corridor(CMEC),the Dulong-Ir-rawaddy(Ayeyarwady)River,an international river among China,India and Myanmar,plays a significant role as both a valuable hydro-power resource and an essential ecological ***,the water resources and security exhibit a high degree of vulnerabil-ity to climate change *** research evaluates climate impacts on the hydrology of the Dulong-Irrawaddy River Basin(DIRB)by using a physical-based hydrologic *** crafted future climate scenarios using the three latest global climate models(GCMs)from Coupled Model Intercomparison Project 6(CMIP6)under two shared socioeconomic pathways(SSP2-4.5 and SSP5-8.5)for the near(2025-2049),mid(2050-2074),and far future(2075-2099).The regional model using MIKE SHE based on historical hydrologic processes was developed to further project future streamflow,demonstrating reliable performance in streamflow simulations with a val-idation Nash-Sutcliffe Efficiency(NSE)of *** showed that climate change projections showed increases in the annual precip-itation and potential evapotranspiration(PET),with precipitation increasing by 11.3%and 26.1%,and PET increasing by 3.2%and 4.9%,respectively,by the end of the century under SSP2-4.5 and *** changes are projected to result in increased annual streamflow at all stations,notably at the basin’s outlet(Pyay station)compared to the baseline period(with an increase of 16.1%and 37.0%at the end of the 21st century under SSP2-4.5 and SSP5-8.5,respectively).Seasonal analysis for Pyay station forecasts an in-crease in dry-season streamflow by 31.3%-48.9%and 22.5%-76.3%under SSP2-4.5 and SSP5-8.5,respectively,and an increase in wet-season streamflow by 5.8%-12.6%and 2.8%-33.3%,***,the magnitude and frequency of flood events are pre-dicted to escalate,potentially impacting hydropower production and food security *** res

关键词： climate change hydrologic response Coupled Model Intercomparison Project 6(CMIP6) MIKE SHE(Système Hydrologique Europeén) Dulong-Irrawaddy River Basin

Fast source mask co-optimization method for high-NA EUV lithography

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Opto-Electronic Advances 2024年第4期7卷 44-54页

作者： Ziqi Li Lisong Dong xu ma Yayi Wei EDA Center Institute of Microelectronics of Chinese Academy of SciencesBeijing 100029China Key Laboratory of Photoelectronic Imaging Technology and System of Ministry of Education of China School of Optics and PhotonicsBeijing Institute of TechnologyBeijing 100081China University of Chinese Academy of Sciences Beijing 100049China Guangdong Greater Bay Area Applied Research Institute of Integrated Circuit and Systems Guangzhou 510700China

Extreme ultraviolet(EUV)lithography with high numerical aperture(NA)is a future technology to manufacture the integrated circuit in sub-nanometer ***,source mask co-optimization(SMO)is an extensively used approach for advanced lithography process beyond 28 nm technology *** work proposes a novel SMO method to improve the image fidelity of high-NA EUV lithography system.A fast high-NA EUV lithography imaging model is established first,which includes the effects of mask three-dimensional structure and anamorphic ***,this paper develops an efficient SMO method that combines the gradient-based mask optimization algorithm and the compressivesensing-based source optimization algorithm.A mask rule check(MRC)process is further proposed to simplify the optimized mask *** illustrate that the proposed SMO method can significantly reduce the lithography patterning error,and maintain high computational efficiency.

关键词： computational lithography high-NA EUV lithography source-mask co-optimization lithography imaging model

Further Results on Stability Analysis for Sampled-Data Systems via Refined Semi-Looped-Functional

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Journal of Systems Science & Complexity 2024年第1期37卷 318-328页

作者： SHENG Zhaoliang xu Shengyuan ma Qian ZHANG Baoyong School of Automation Nanjing University of Science and TechnologyNanjing 210094China

This paper investigates the stability problem for sampled-data systems by adopting a refined semi-looped-functional,which is with the following two ***,the new functional term is with a new integral vectorη0,which contains sampling information of the systems and associates two commonly used ***,the vectorη0 is combined into various zero equations for processing the functional,especially where a new equation is derived fromη*** on the refined functional,further stability results for sampled-data systems are *** the effectiveness of the results is numerically verified through two examples at the end.

关键词： Integral vector sampled-data systems semi-looped-functional stability analysis.

Accurate Analysis of Multi-Mode Interferometric Optical Fiber Sensor

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Photonic Sensors 2024年第1期14卷 48-58页

作者： Lijun LI Congying JIA Qian ma Tianzong xu College of Electronic and Information Engineering Shandong University of Science and TechnologyQingdao 266590.China State Key Laboratory of Mining Disaster Prevention and Control Co-Founded by Shandong Province and the Ministry of Science and Technology Qingdao 266590China

In view of the problem that the sensing characteristics of the multi-mode interferometric fiber sensors cannot be accurately analyzed,an analysis method based on the fast Fourier transform(FFT)and inverse fast Fourier transform(IFFT)is proposed and demonstrated theoretically and *** suitabilities of the rectangular window function with the narrow main lobe(high spectrum resolution)and low side lobe(high main mode energy leakage)and the Hanning window function with the wide main lobe(low spectrum resolution)and high side lobe(high energy concentration)in this kind of sensor analysis are discussed,*** method can not only realize the sensing performance analysis of the various modes,but also overcome the inconsistency of the different interference wavelength(dip)sensing characteristics in the conventional analysis *** the same time,this method is also beneficial to solve the repetitive problem of such sensors.

关键词： Window function FFT optical fiber interferometric sensor analysis method