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Predicting electronic structures at any length scale with machine learning

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npj Computational Materials 2023年第1期9卷 1176-1185页

作者： Lenz Fiedler Normand A.Modine Steve Schmerler Dayton J.Vogel Gabriel A.Popoola aidan P.thompson Sivasankaran Rajamanickam Attila Cangi Center for Advanced Systems Understanding D-02826 GörlitzGermany Helmholtz-Zentrum Dresden-Rossendorf D-01328 DresdenGermany Computational Materials and Data Science Sandia National Laboratories1515 Eubank BlvdAlbuquerque 87123 NMUSA Elder Research Inc.300 West Main StreetCharlottesville 22903 VAUSA Center for Computing Research Sandia National Laboratories1515 Eubank BlvdAlbuquerque 87123 NMUSA

The properties of electrons in matter are of fundamental *** give rise to virtually all material properties and determine the physics at play in objects ranging from semiconductor devices to the interior of giant gas *** and simulation of such diverse applications rely primarily on density functional theory(DFT),which has become the principal method for predicting the electronic structure of *** DFT calculations have proven to be very useful,their computational scaling limits them to small *** have developed a machine learning framework for predicting the electronic structure on any length *** shows up to three orders of magnitude speedup on systems where DFT is tractable and,more importantly,enables predictions on scales where DFT calculations are *** work demonstrates how machine learning circumvents a long-standing computational bottleneck and advances materials science to frontiers intractable with any current solutions.

关键词： electronic interior frontier

Performant implementation of the atomic cluster expansion(PACE)and application to copper and silicon

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npj Computational Materials 2021年第1期7卷 878-889页

作者： Yury Lysogorskiy Cas van der Oord Anton Bochkarev Sarath Menon Matteo Rinaldi Thomas Hammerschmidt Matous Mrovec aidan thompson Gábor Csányi Christoph Ortner Ralf Drautz ICAMS Ruhr-Universität BochumBochumGermany Engineering Laboratory University of CambridgeCambridgeUK Center for Computing Research Sandia National LaboratoriesAlbuquerqueNMUSA Department of Mathematics University of British ColumbiaVancouverBCCanada

The atomic cluster expansion is a general polynomial expansion of the atomic energy in multi-atom basis *** we implement the atomic cluster expansion in the performant C++code PACE that is suitable for use in large-scale atomistic *** briefly review the atomic cluster expansion and give detailed expressions for energies and forces as well as efficient algorithms for their *** demonstrate that the atomic cluster expansion as implemented in PACE shifts a previously established Pareto front for machine learning interatomic potentials toward faster and more accurate ***,general purpose parameterizations are presented for copper and silicon and evaluated in *** show that the Cu and Si potentials significantly improve on the best available potentials for highly accurate large-scale atomistic simulations.

关键词： functions expansion cluster

Simplified prediction models for acoustic installation effects of train-mounted equipment

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Railway Engineering Science 2024年第2期32卷 125-143页

作者： David thompson Dong Zhao Giacomo Squicciarini Institute of Sound and Vibration Research University of SouthamptonSouthampton SO171BJUK

Acoustic models of railway vehicles in standstill and pass-by conditions can be used as part of a virtual certification process for new *** each piece of auxiliary equipment,the sound power measured on a test bench is combined with meas-ured or predicted transfer *** is important,however,to allow for installation effects due to shielding by fairings or the train *** the current work,fast-running analytical models are developed to determine these installation *** model for roof-mounted sources takes account of diffraction at the corner of the train body or fairing,using a barrier *** equipment mounted under the train,the acoustic propagation from the sides of the source is based on free-field Green’s *** bottom surfaces are assumed to radiate initially into a cavity under the train,which is modelled with a simple diffuse field *** sound emitted from the gaps at the side of the cavity is then assumed to propagate to the receivers according to free-field Green’s *** show good agreement with a 2.5D boundary element model and with *** uncertainty and parametric uncertainty are *** largest variability occurs due to the height and impedance of the ground,especially for a low *** leads to standard deviations of up to 4 dB at low *** the roof-mounted sources,uncertainty over the location of the corner used in the equivalent barrier model can also lead to large standard deviations.

关键词： Train noise Auxiliary equipment Acoustic installation effects Virtual certification Uncertainty

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A proton birdcage coil integrated with interchangeable single loops for multi-nuclear MRI/MRS

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2024年第2期25卷 168-180页

作者： Yi ZHANG Zhiyan QUAN Feiyang LOU Yujiao FANG Garth J.thompson Gao CHEN Xiaotong ZHANG Department of Neurosurgery the Second Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhou310009China Key Laboratory of Precise Treatment and Clinical Translational Research of Neurological Diseases Hangzhou310009China MOE Frontier Science Center for Brain Science and Brain-machine Integration Zhejiang UniversityHangzhou310058China Interdisciplinary Institute of Neuroscience and Technology College of Biomedical Engineering&Instrument ScienceZhejiang UniversityHangzhou310027China School of Medicine Zhejiang UniversityHangzhou310020China iHuman Institute School of Life Science and TechnologyShanghaiTech UniversityShanghai201210China College of Electrical Engineering Zhejiang UniversityHangzhou310027China

Energy metabolism is fundamental for *** encompasses the utilization of carbohydrates,lipids,and proteins for internal processes,while aberrant energy metabolism is implicated in many *** the present study,using three-dimensional(3D)printing from polycarbonate via fused deposition modeling,we propose a multi-nuclear radiofrequency(RF)coil design with integrated 1H birdcage and interchangeable X-nuclei(^(2)H,^(13)C,^(23)Na,and^(31)P)single-loop coils for magnetic resonance imaging(MRI)/magnetic resonance spectroscopy(MRS).The single-loop coil for each nucleus attaches to an arc bracket that slides unrestrictedly along the birdcage coil inner surface,enabling convenient switching among various nuclei and animal *** to a commercial 1H birdcage coil,the proposed 1H birdcage coil exhibited superior signal-excitation homogeneity and imaging signal-to-noise ratio(SNR).For X-nuclei study,prominent peaks in spectroscopy for phantom solutions showed excellent SNR,and the static and dynamic peaks of in vivo spectroscopy validated the efficacy of the coil design in structural imaging and energy metabolism detection simultaneously.

关键词： Energy metabolism Magnetic resonance imaging(MRI) Magnetic resonance spectroscopy(MRS) Multi-nuclear Radiofrequency coil Three-dimensional(3D)printing

Robotic-assisted versus laparoscopic repair of type II, III and IV hiatal hernias: A retrospective study comparing adverse outcomes

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Laparoscopic, Endoscopic and Robotic Surgery 2024年第1期7卷 11-15页

作者： Payton Kooiker Shane Monnett Stephanie thompson Bryan Richmond West Virginia School of Osteopathic Medicine LewisburgWV24901United States Department of Surgery Charleston Area Medical CenterCharlestonWV25304United States

Objective:Robotic-assisted surgery(RAS)is continuing to expand in use in surgical specialties,including foregut *** available data on its use in large hiatal hernia(HH)repair are limited and *** study sought to determine whether there are significant differences in adverse outcomes following HH repair performed with a robotic approach vs.a laparoscopic *** study was limited to outcomes in patients with type II,III,and IV HHs,as these hernias are typically more challenging to ***:A retrospective analysis was performed from data obtained from TriNetX,a large deidentified clinical database,over a 10-year *** patients who underwent type II,III,or IV HH repair were included in the *** with robotic repair was compared to laparoscopic *** were propensity score matched for demographic information and *** ratios,risk differences(RDs)with 95%confidence intervals(CIs),and t test for each examined adverse outcome were used to estimate the effects of robotic repair *** ***:In total,20,016 patients who met the inclusion criteria were identified;1,515 patients utilized RAS,and 18,501 used *** to matching,there were significant differences in age,sex,comorbidity,and BMI between the two *** 1:1 propensity score matching,analyses of 1,514 well-matched patient pairs revealed no significant differences in demographics or *** who underwent robotic repair were more likely to experience major complications,including venous thromboembolism(RD:0.007,95%CI:0.003,0.011;p?0.002),critical care(RD:0.023,95%CI:0.007,0.039;p?0.004),urinary/renal complications(RD:0.027,95%CI:0.014,0.041;p<0.001),and respiratory complications(RD:0.046,95%CI:0.028,0.064;p<0.001).RAS was associated with a significantly shorter length of stay(32.4±27.5 h vs.35.7±50.1 h,p?0.031),although this finding indicated a reduction in the length of stay of less than 4 *** statist

关键词： Hiatal hernia Robotic-assisted surgery Laparoscopic surgery Adverse outcomes

Reduction of epinephrine in the lumbar spinal cord following repetitive blast-induced traumatic brain injury in rats

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Neural Regeneration Research 2024年第7期19卷 1548-1552页

作者： Shigeharu Tsuda Mustafa Golam Jiamei Hou Kevin K.W.Wang Floyd J.thompson Prodip Bose Brain Rehabilitation Research Center Malcom Randall VA Medical CenterNorth Florida/South Georgia Veterans Health SystemGainesvilleFLUSA Department of Anesthesiology College of MedicineUniversity of FloridaGainesvilleFLUSA Department of Emergency Medicine University of FloridaGainesvilleFLUSA Department of Neuroscience University of FloridaGainesvilleFLUSA Department of Neurology University of FloridaGainesvilleFLUSA

Traumatic brain inju ry-induced unfavorable outcomes in human patients have independently been associated with dysregulated levels of monoamines,especially epinephrine,although few preclinical studies have examined the epinephrine level in the central nervous system after traumatic brain *** has been shown to regulate the activities of spinal motoneurons as well as increase the heart rate,blood pressure,and blood flow to the hindlimb ***,the purpose of the present study was to determine the impact of repeated blast-induced traumatic brain injury on the epinephrine levels in seve ral function-s pecific central nervous system regions in *** three repeated blast injuries at 3-day intervals,the hippocampus,motor cortex,locus coeruleus,vestibular nuclei,and lumbar spinal cord were harvested at post-injury day eight and processed for epinephrine assays using a high-sensitive electrochemical detector cou pled with high-performance liquid *** results showed that the epinephrine levels were significantly decreased in the lumbar spinal cord tissues of blast-induced traumatic brain injury animals compared to the levels detected in age-and sex-matched sham *** other function-specific central nervous system regions,although the epinephrine levels were slightly altered following blast-induced tra u matic brain injury,they were not statistically *** results suggest that blast injury-induced significant downregulation of epinephrine in the lumbar spinal cord could negatively impact the motor and cardiovascular *** is the first repo rt to show altered epinephrine levels in the spinal cord following repetitive mild blast-induced traumatic brain injury.

关键词： balance blood flow cardiovascular system central nervous system epinephrine ischemic damage lumbar spinal cord muscle tone repeated blast spasticity traumatic brain injury

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Design,Synthesis,and Applications of Mesoporous Covalent Organic Frameworks

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CCS Chemistry 2024年第1期6卷 57-68页

作者： Niyati Arora Cassandra Flores Milinda C.Senarathna Christina M.thompson Ronald A.Smaldone Department of Chemistry and Biochemistry University of TexasDallasRichardsonTexas 75080

Covalent organic frameworks(COFs)are highly ordered and permanently porous organic polymers that can be classified as two-dimensional or *** tunable design and crystalline order endow a range of pore sizes,shapes,functions,and applications that differentiate them from other *** COF pore sizes and shapes rely on the geometry of the monomers and dynamic covalent chemistry,while the stacking of the sheets relies on noncovalent *** tunability allows for post-modification or the incorporation of additional functional groups for the reinforcement by various noncovalent *** limits of mesoporous COFs are still being investigated,with the design rules continuing to *** we report a comprehensive review of mesoporous COFs,explore strategies for large pore reinforcement,highlight structural design and features,elucidate their various functions and applications,discuss fundamental challenges faced that need to be addressed,and predict future directions.

关键词： covalent organic frameworks mesoporous supramolecular chemistry polymers pore size

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轨道车辆一系螺旋弹簧振动疲劳失效分析

振动与冲击 2024年第1期43卷 230-236页

作者：孙文静王嘉豪 thompson David 王腾飞周劲松同济大学铁道与城市轨道交通研究院上海201804 Institute of Sound and Vibration Research University of SouthamptonSouthampton SO171BJUK

轨道车辆服役工况下一系悬挂系统中的金属螺旋弹簧疲劳断裂时有发生,影响列车运行安全性。针对某一系螺旋弹簧疲劳失效故障,考虑轮轨激励与弹簧结构动态特性耦合关系,建立准确提取弹簧载荷的模型,通过结构频域疲劳分析法计算弹簧动应力... 详细信息

轨道车辆服役工况下一系悬挂系统中的金属螺旋弹簧疲劳断裂时有发生,影响列车运行安全性。针对某一系螺旋弹簧疲劳失效故障,考虑轮轨激励与弹簧结构动态特性耦合关系,建立准确提取弹簧载荷的模型,通过结构频域疲劳分析法计算弹簧动应力响应与疲劳寿命。首先考虑螺旋弹簧结构的动态特性,建立包含一系动刚度特性的车辆-轨道耦合精细化动力学模型,然后在轮轨激励下提取服役工况弹簧两端动载荷,最后采用结构频域疲劳分析法计算弹簧动应力响应与疲劳寿命,并与实测动应力结果进行对比验证。结果表明:螺旋弹簧自身动态特性体现在:多阶模态频率下弹簧中部的最大模态变形与簧条1~2圈间的最大模态应力;基于耦合动力学模型,计算得到内簧动应力响应与实测结果一致,在58 Hz的动应力峰值是其它频率动应力峰值的3倍以上;由于内簧一阶固有频率与轮轨系统P2共振频率接近,弹簧内部共振引起簧条1.2圈内侧高应力,该处疲劳寿命最短的分析结果与现场断裂位置吻合,而外簧的最短疲劳寿命约为内簧的3.6倍。因此,同时考虑轮轨激励与螺旋弹簧自身动态特性,使得一系螺旋弹簧固有频率远离轮轨共振频率,可提高弹簧结构的抗疲劳特性。

关键词：轨道车辆螺旋弹簧模态频率动应力振动疲劳

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一种用于多核磁共振成像及波谱的鸟笼线圈与可更换单环线圈的一体化设计（英文）

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2024年第2期 168-181页

作者：张怡全枝艳楼飞洋方玉娇 Garth J.thompson 陈高张孝通浙江大学医学院附属第二医院神经外科浙江省神经外科疾病精准诊治及临床转化重点实验室浙江大学教育部脑与脑机融合前沿科学中心浙江大学系统神经与认知科学研究所浙江大学医学院上海科技大学iHuman研究所浙江大学电气工程学院

能量代谢对生命活动至关重要，主要包括对碳水化合物、脂肪和蛋白质的利用过程，异常的能量代谢与诸多疾病密切相关。本研究提出了一种用于多核磁共振成像(MRI)与波谱(MRS)的射频线圈设计：通过3D打印线圈外壳和支架，将一个鸟笼1H线圈... 详细信息

能量代谢对生命活动至关重要，主要包括对碳水化合物、脂肪和蛋白质的利用过程，异常的能量代谢与诸多疾病密切相关。本研究提出了一种用于多核磁共振成像(MRI)与波谱(MRS)的射频线圈设计：通过3D打印线圈外壳和支架，将一个鸟笼1H线圈和可更换的单环X核(2H、13C、23Na和31P)线圈一体化集成，其中单环线圈通过一个弧形支架安装于鸟笼线圈内壁，使其可沿内壁轴向无阻碍地移动，方便实现成像实验中多核线圈的更换以及线圈相对于不同成像体的摆放。与商用鸟笼1H核线圈相比，本设计具有更好的1H信号激发均匀性和成像信噪比；小鼠的活体实验验证了线圈设计在成像与波谱研究方面的可行性与有效性，可同时满足结构成像和能量代谢检测的要求。综上所述，该多核线圈通过新型机械与电路设计可以简化多核磁共振成像能量代谢检测的实施过程。

关键词：能量代谢核磁共振成像磁共振波谱多核射频线圈 3D打印