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Correcting the corrections for charged defects in crystals

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npj Computational Materials 2021年第1期7卷 680-682页

作者： aron Walsh Department of Materials Imperial College LondonLondonUK The Faraday Institution Quad OneDidcotUK Department of Materials Science and Engineering Yonsei UniversitySeoulKorea

While the theory of imperfections in solids is firmly established,procedures for first-principles calculations of defect quantities continue to evolve.A plethora of ad hoc correction schemes is being replaced by sophisticated self-consistent procedures that will enable more quantitative predictions of the formation energies of defect species and their spectroscopic signatures.

关键词： correction defect quantities

Electrodynamics of Abrikosov vortices： the field theoretical formulation

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Frontiers of physics 2011年第4期6卷 357-369页

作者： aron J. Beekman Jan Zaanen Instituut-Lorentz for Theoretical Physics Universiteit Leiden P. O. Box 9506 2300 RA Leiden The Netherlands

Electrodynamic phenomena related to vortices in superconductors have been studied since their prediction by Abrikosov, and seem to hold no fundamental mysteries. However, most of the effects are treated separately, with no guiding principles. We demonstrate that the relativistic vortex worldsheet in spacetime is the object that naturally conveys all electric and magnetic information, for which we obtain simple and concise equations. Breaking Lorentz invariance leads to down-to-earth Abrikosov vortices, and special limits of these equations include for instance dynamic Meissner screening and the AC Josephson relation. On a deeper level, we explore the electrodynamics of two-form sources in the absence of electric monopoles, in which the electromagnetic field strength itself acquires the characteristics of a gauge field. This novel framework leaves room for unexpected surprises .

关键词： Abrikosov vortex, electromagnetism, Maxwell equations, differential geometry multivalued fields

Prediction of high thermoelectric performance in the lowdimensional metal halide Cs_(3)Cu_(2)I_(5)

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npj Computational Materials 2021年第1期7卷 476-481页

作者： Young-Kwang Jung In Taek Han Yong Churl Kim aron Walsh Department of Materials Science and Engineering Yonsei UniversitySeoulSouth Korea Samsung Advanced Institute of Technology(SAIT) Samsung Electronics Materials Research ComplexYoungtongSuwonSouth Korea Department of Materials Imperial College LondonLondonUK

Metal halides have emerged as a new generation of semiconductors with applications ranging from solar cells to chemical *** assess the thermoelectric potential of Cs_(3)Cu_(2)I_(5),which has a crystal structure formed of zero-dimensional[Cu_(2)I_(5)]3−anionic clusters that are separated by Cs+counter *** find the compound exhibits the characteristics of a phonon-glass electroncrystal with a large imbalance in the conduction of heat and electrons predicted from first-principles transport *** anharmonic phonon–phonon scattering results in short-lived acoustic vibrations and an ultra-low lattice thermal conductivity(10 cm^(2)V^(−1)s^(−1)).For an n-type crystal at 600 K,a thermoelectric figure-of-merit ZT of 2.6 is found to be accessible,which for a cold source of 300 K corresponds to a thermodynamic heat-to-electricity conversion efficiency of 15%.

关键词： theory phonon crystal

Israeli trauma system: on constant alert

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Emergency and Critical Care Medicine 2022年第2期2卷 83-86页

作者： Miklosh Bala Joshua Z.gottesman Department of General Surgery Hadassah Medical Center and Faculty of MedicineHebrew University of JerusalemIsrael

A trauma system is a chain of activities to provide quality response to the injured from the site of injury to the appropriate hospital and *** has a unique trauma system developed from the experience gained in peace and in *** is characterized by a central national organization responsible for management,coordination,and ongoing quality *** of the unique situation,the Israeli Defense Forceshas a significant role in the *** order to develop an effective trauma system,it is important to devote sufficient resources in education,training,motivation,team-work,and creation of public volunteers for capacity *** effective trauma system manages mass casualty incidence(MCI)*** quickly reorganized in order to accommodate the sudden needs of patients with coronavirus disease 2019(COVID-19),while being able to maintain the routine surgical and medical requirements of the *** aim of this article is to present the main components of the Israeli trauma model.

关键词： Israeli model Mass casualty preparedness Trauma system

Low-thermal-budget electrically active thick polysilicon for CMOS-First MEMS-last integration

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Microsystems & Nanoengineering 2024年第3期10卷 395-407页

作者： aron Michael Ian Yao-Hsiang Chuang Chee Yee Kwok Kazuo Omaki UNSW SydneyNSW 2052Australia

Low-thermal-budget,electrically active,and thick polysilicon films are necessary for building a microelectromechanical system(MEMS)on top of a complementary metal oxide semiconductor(CMOS).However,the formation of these polysilicon films is a challenge in this ***,for the first time,the development of in situ phosphorus-doped silicon films deposited under ultrahigh-vacuum conditions(~10^(−9)Torr)using electron-beam evaporation(UHVEE)is *** process results in electrically active,fully crystallized,low-stress,smooth,and thick polysilicon films with low thermal *** crystallographic,mechanical,and electrical properties of phosphorus-doped UHVEE polysilicon films are *** films are compared with intrinsic and boron-doped UHVEE silicon *** spectroscopy,X-ray diffraction(XRD),transmission electron microscopy(TEM)and atomic force microscopy(AFM)are used for crystallographic and surface morphological *** curvature,cantilever deflection profile and resonance frequency measurements are employed to study the mechanical properties of the ***,resistivity measurements are conducted to investigate the electrical properties of the *** vertical,high-aspectratio micromachining of UHVEE polysilicon has been developed.A comb-drive structure is designed,simulated,fabricated,and characterized as an actuator and inertial sensor comprising 20-μm-thick in situ phosphorus-doped UHVEE films at a temperature less than 500℃.The results demonstrate for the first time that UHVEE polysilicon uniquely allows the realization of mechanically and electrically functional MEMS devices with low thermal budgets.

关键词： budget thick thermal

Perovskite synthesizability using graph neural networks

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npj Computational Materials 2022年第1期8卷 697-704页

作者： Geun Ho Gu Jidon Jang Juhwan Noh aron Walsh Yousung Jung Department of Chemical and Biomolecular Engineering(BK21 four) KAIST291 Daehak-ro 34141Daejeon305-335South Korea School of Energy Technology Korea Institute of Energy Technology200 Hyuksin-roNaju58330South Korea Department of Materials Imperial College LondonLondonSW72AZUK Department of Materials Science and Engineering Yonsei UniversitySeoul03722South Korea

Perovskite is an important material type in geophysics and for technologically important ***,the number of synthetic perovskites remains relatively *** accelerate the high-throughput discovery of perovskites,we propose a graph neural network model to assess their *** trained model shows a promising 0.957 out-of-sample true positive rate,significantly improving over empirical rule-based *** validation is established by demonstrating that a significant portion of the virtual crystals that are predicted to be synthesizable have already been indeed synthesized in literature,and those with the lowest synthesizability scores have not been *** previous empirical strategies are mainly applicable to metal oxides,our model is general and capable of predicting the synthesizability across all classes of perovskites,including chalcogenide,halide,and hydride perovskites,as well as *** apply the method to identify synthesizable perovskite candidates for two potential applications,the Li-rich ion conductors and metal halide optical materials that can be tested experimentally.

关键词： methods. perovskite halide

Comment on ＂Comparison of 45-degree Kelman and 45-degree balanced phaco tip designs in torsional microcoaxial phacoemulsification＂

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International Journal of Ophthalmology(English edition) 2017年第8期10卷 1334-1336页

作者： Neelima aron Sagnik Sen Sudarshan Khokhar Department of Ophthalmology Dr. Rajendra Prasad Centre for Ophthalmic Sciences All India Institute of Medical Sciences New Delhi 110029 India

Dear Editor,We read with interest the article ＂Comparison of 45-degree Kelman and 45-degree balanced phaco tip designs in torsional microcoaxial phacoemulsification＂ by Demircan et al. The authors describe the intraoperative and post-operative outcomes of phacoemulsification in terms of cumulative dissipated energy （CDE）, total ultrasound （US） time, torsional US time, total fluid use, percentage change in central corneal thickness and endothelial cell count in the two groups. A comparative evaluation has been made between the two groups involving the Kelman mini-flared tip and the Intrepid balanced phaco tip using the Infiniti Ozil IP Vision system （Alton Laboratories Inc., Fort Worth, TX, USA） as hasbeen explicitly mentioned in the article under the ＂Methods＂ section. However,

关键词： Vision Comment on Comparison of 45-degree Kelman and 45-degree balanced phaco tip designs in torsional microcoaxial phacoemulsification

Travel time reliability with and without the dynamic use of hard shoulder:Field assessment from a French motorway

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Journal of Traffic and Transportation Engineering(English Edition) 2016年第6期3卷 520-530页

作者： Neila Bhouri Maurice aron Gerard Scemama IFSTFAR/COSYS/GRETFIA Laboratory Universite Paris-EstMarne-la-vallee 77447France

Traffic management aims to ensure a high quality of service for most users by decreasing congestion and increasing safety. However, uncertainty regarding travel time decreases the quality of service and leads end-users to change their routes and schedules even when the average travel time is low, Indicators describing travel time reliability are being developed and should be used in the future both for the optimization and the assessment of active traffic management operation. This paper describes a managed lane experience on a motorway weaving section in France - hard shoulder running operation in rush hours. The paper is focused on travel time reliability indicators and their use for reliability assessment. It provides some discussions about the advantages and drawbacks of reliability indicators under different traffic conditions. It particularly shows the difference between using buffer times and buffer indexes. The paper also discusses the difficulty of interpreting the skew of travel time distribution for travel reliability,

关键词： Travel reliability Travel time Managed lanes Hard shoulder Recurrent congestion Traffic management assessment

Intrinsic Instability of the Hybrid Halide Perovskite Semiconductor CH3NH3PbI3

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Chinese Physics Letters 2018年第3期35卷 52-57页

作者：张越宇陈时友许朋向红军龚新高 aron Walsh 魏苏淮 Key Laboratory for Computational Physical Sciences(MOE) State Key Laboratory of Surface Physicsand Department of PhysicsFudan UniversityShanghai 200433 Key Laboratory of Polar Materials and Devices(MOE) East China Normal UniversityShanghai 200241 Center for Sustainable Chemical Technologies and Department of Chemistry University of BathBath BA2 7AYUK Beijing Computational Science Research Center Beijing 100094

The organic-inorganic hybrid perovskite CH3NH3PbI3 has attracted significant interest for its high performance in converting solar light into electrical power with an efficiency exceeding 20%. Unfortunately, chemical stability is one major challenge in the development of CH3NH3PbI3 solar cells. It was commonly assumed that moisture or oxygen in the environment causes the poor stability of hybrid halide perovskites, however, here we show from the first-principles calculations that the room-temperature tetragonal phase of CH3NH3PbI3 is thermodynamically unstable with respect to the phase separation into CH3NH3I ＋ PbI2, i.e., the disproportionation is exothermic, independent of the humidity or oxygen in the atmosphere. When the structure is distorted to the low-temperature orthorhombie phase, the energetic cost of separation increases, but remains small. Contributions from vibrational and configurational entropy at room temperature have been considered, but the instability of CH3NH3PbI3 is unchanged. When I is replaced by Br or CI, Pb by Sn, or the organic cation CH3NH3 by inorganic Cs, the perovskites become more stable and do not phase-separate spontaneously. Our study highlights that the poor chemical stability is intrinsic to CH3NH3PbI3 and suggests that element-substitution may solve the chemical stability problem in hybrid halide perovskite solar cells.

关键词： NH Pb CH Intrinsic Instability of the Hybrid Halide Perovskite Semiconductor CH3NH3PbI3