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100pT/cm single-point MEMS magnetic gradiometer from a commercial accelerometer

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Microsystems & Nanoengineering 2020年第1期6卷 602-614页

作者： josh javor Alexander Stange Corey pollock Nicholas Fuhr David j.Bishop Department of Mechanical Engineering Boston UniversityBostonMA 02215USA Division of Materials Science and Engineering Boston UniversityBostonMA 02215USA Department of Electrical and Computer Engineering Boston UniversityBostonMA 02215USA Department of Physics Boston UniversityBostonMA 02215USA Department of Biomedical Engineering Boston UniversityBostonMA 02215USA

Magnetic sensing is present in our everyday interactions with consumer electronics and demonstrates the potential for the measurement of extremely weak biomagnetic fields,such as those of the heart and *** this work,we leverage the many benefits of microelectromechanical system(MEMS)devices to fabricate a small,low-power,and inexpensive sensor whose resolution is in the range of biomagnetic *** present,biomagnetic fields are measured only by expensive mechanisms such as optical pumping and superconducting quantum interference devices(SQUIDs),suggesting a large opportunity for MEMS technology in this *** prototype fabrication is achieved by assembling micro-objects,including a permanent micromagnet,onto a postrelease commercial MEMS accelerometer using a pick-and-place *** this system,we demonstrate a room-temperature MEMS magnetic *** air,the sensor’s response is linear,with a resolution of 1.1 nT cm^(−1),spans over 3 decades of dynamic range to 4.6µT cm^(−1),and is capable of off-resonance measurements at low *** a 1mTorr vacuum with 20 dB magnetic shielding,the sensor achieves a 100 pT cm^(−1) resolution at *** resolution represents a 30-fold improvement compared with that of MEMS magnetometer technology and a 1000-fold improvement compared with that of MEMS gradiometer *** sensor is capable of a small spatial resolution with a magnetic sensing element of 0.25 mm along its sensitive axis,a>4-fold improvement compared with that of MEMS gradiometer *** calculated noise floor of this platform is 110 fTcm^(−1) Hz−1/2,and thus,these devices hold promise for both magnetocardiography(MCG)and magnetoencephalography(MEG)applications.

关键词： accelerometer magnetometer everyday

Damage mechanism identification in composites via machine learning and acoustic emission

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npj Computational Materials 2021年第1期7卷 852-866页

作者： C.Muir B.Swaminathan A.S.Almansour K.Sevener C.Smith M.Presby j.D.Kiser T.M.pollock S.Daly Materials Department University of California-Santa BarbaraSanta BarbaraCAUSA NASA Glenn Research Center ClevelandOHUSA Materials Scienceand Engineering Department University of Michigan-Ann ArborAnn ArborMIUSA Mechanical Engineering Department University of California-Santa BarbaraSanta BarbaraCAUSA

Damage mechanism identification has scientific and practical ramifications for the structural health monitoring,design,and application of composite *** advances in machine learning uncover pathways to identify the waveform-damage mechanism relationship in higher-dimensional spaces for a comprehensive understanding of damage *** review evaluates the state of the field,beginning with a physics-based understanding of acoustic emission waveform feature extraction,followed by a detailed overview of waveform clustering,labeling,and error analysis *** requirements for damage mechanism identification in any machine learning framework,including those currently in use,under development,and yet to be explored,are discussed.

关键词： composites composite mechanism

Efficacy of Ciji Hua'ai Baosheng formula on the expressions of vascular endothelial growth factor,kinase insert domain-containing receptor and basic fibroblast growth factor in mouse models of H22 hepatocellular carcinoma

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journal of Traditional Chinese Medicine 2017年第1期37卷 88-95页

作者： Zhao Xinyue Xi Shengyan Wang Yanhui Xu Yangxinzi pollock Galia Su Yu Cheng Yao Loy Guanjie Liu Pei Department of Traditional Chinese Medicine Medical College of Xiamen University Cancer Research Center of Xiamen University Xiamen 361102China Department of Internal Medicine John Buhler Research CentreUniversity of ManitobaWinnipeg FI3E 3P4Canada

OBjECTIVE: To investigate the efficacy of Ciji Hua'ai Baosheng formula(CHBF) on microvessel density(MVD) and vascular endothelial growth factor(VEGF), kinase insert domain-containing receptor(KDR) and basic fibroblast growth factor(b FGF) expression in serum and tumor tissue of mice receiving chemotherapy for the treatment of H22 hepatocellular ***: Sixty Kunming mice were injected subcutaneously with H22 hepatoma carcinoma cell suspensions into the right anterior armpit. Seven days later, all transplanted tumor were formed and the mice were intraperitoneally injected 200 mg/kg cytoxan(CTX) to establish the models of tumor-bearing mouse chemotherapy, then they were randomly divided into model group, continuing CTX chemotherapy group(CTX group), and three CHBF(117, 58.5 and 29.25 g/kg) groups. After ten days of treatments, histology was observed, contents of VEGF, KDR and b FGF in serum and tumor tissue were measured by enzyme-linked immunosorbent assay(ELISA), VEGF and b FGF protein expression and MVD tagged by CD34 were detected by ***: MVD in CHBF(117, 58.5 g/kg) and CTX groups was significantly lower than that in model group(P < 0.01); expressions of VEGF, KDR and b FGF in serum and tumor tissue in CHBF(117 g/kg)group were less than those in model group(P <0.05; P < 0.01); the expressions of MVD, VEGF and b FGF in tumor tissue of CHBF(117 g/kg) groupwere also less than those in CTX group(P < 0.05;P < 0.01).CONCLUSION: CHBF can effectively reduce the expression of VEGF, KDR and b FGF in serum and tumor tissue, and decrease MVD and delay tumor progression.

关键词： Drug therapy Angiogenesis inhibitors Vascular endothelial growth factors Receptors vascular endothelial growth factor Basic fibroblast growth factor 2 Ciji Hua’ai Baosheng formula

A machine learning framework for damage mechanism identification from acoustic emissions in unidirectional SiC/SiC composites

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npj Computational Materials 2021年第1期7卷 1326-1335页

作者： C.Muir B.Swaminathan K.Fields A.S.Almansour K.Sevener C.Smith M.Presby j.D.Kiser T.M.pollock S.Daly Materials University of California-Santa BarbaraSanta BarbaraCAUSA Mechanical Engineering University of California-Santa BarbaraSanta BarbaraCAUSA NASA Glenn Research Center ClevelandOHUSA Materials Science and Engineering University of Michigan-Ann ArborAnn ArborMIUSA

In this work,we demonstrate that damage mechanism identification from acoustic emission(AE)signals generated in minicomposites with elastically similar constituents is *** waveforms were generated by SiC/SiC ceramic matrix minicomposites(CMCs)loaded under uniaxial tension and recorded by four sensors(two models with each model placed at two ends).Signals were encoded with a modified partial power scheme and subsequently partitioned through spectral *** cracking and fiber failure were identified based on the frequency information contained in the AE event they produced,despite the similar constituent elastic properties of the matrix and ***,the resultant identification of AE events closely followed CMC damage chronology,wherein early matrix cracking is later followed by fiber breaks,even though the approach is fully domain-knowledge ***,the partitions were highly precise across both the model and location of the sensors,and the partitioning was *** presented approach is promising for CMCs and other composite systems with elastically similar constituents.

关键词： composites damage mechanism

Proton deflectometry of a capacitor coil target along two axes

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High Power Laser Science and Engineering 2020年第2期8卷 10-18页

作者： P.Bradford M.P.Read M.Ehret L.Antonelli M.Khan N.Booth K.Glize D.Carroll R.j.Clarke R.Heathcote S.Ryazantsev S.Pikuz C.Spindloe j.D.Moody B.B.pollock V.T.Tikhonchuk C.P.Ridgers j.j.Santos N.C.Woolsey York Plasma Institute Department of PhysicsUniversity of YorkHeslingtonYork YO105DDUK Centre Lasers Intenses et Applications University of Bordeaux-CNRS-CEA33405 TalenceFrance Institut fur Kernphysik Tech.Univ.Darmstadt64289 DarmstadtGermany Central Laser Facility Rutherford Appleton LaboratoryChiltonDidcotSTFCUKRIOxfordshireUK joint Institute for High Temperatures RASMoscow 125412Russia National Research Nuclear University MEPhI Moscow 115409Russia Lawrence Livermore National Laboratory LivermoreCalifornia 94551USA ELI Beamlines Institute of PhysicsCzech Academy of SciencesZa Radnicic 83525241 DolníBrezanyCzech Republic

A developing application of laser-driven currents is the generation of magnetic fields of picosecond-nanosecond duration with magnitudes exceeding B=10 ***-loop and helical coil targets can direct laser-driven discharge currents along wires to generate spatially uniform,quasi-static magnetic fields on the millimetre ***,we present proton deflectometry across two axes of a single-loop coil ranging from 1 to 2 mm in *** with proton tracking simulations shows that measured magnetic fields are the result of kiloampere currents in the coil and electric charges distributed around the coil *** this dual-axis platform for proton deflectometry,robust measurements can be made of the evolution of magnetic fields in a capacitor coil target.

关键词： strong magnetic field laser-driven coil targets laser-plasma interaction proton deflectometry laboratory astrophysics

基于MRI的血管周围间隙(mMAPS)的多模态自动识别:血管周围间隙扩大的形态学自动分割的临床应用

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国际医学放射学杂志 2018年第2期 230-231页

作者： L.Boespflug D.L.Schwartz D.Lahna j.pollock j.j.Iliff j.A.Kaye 卜玮艺 Department of Neurology Advanced Imaging Research CenterOregon Health & Science University

摘要目的描述一种全自动分割方法,可用于临床适用场强(3.0 T)MR成像数据,对扩大的血管周围间隙(e PVS)进行基于客观的形态学评估。材料与方法本研究符合HIPAA。

关键词： MRI 血管周围间隙 mMAPS 形态学自动识别多模态

New frontiers for the materials genome initiative

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npj Computational Materials 2019年第1期5卷 776-798页

作者： juan j.de Pablo Nicholas E.jackson Michael A.Webb Long-Qing Chen joel E.Moore Dane Morgan Ryan jacobs Tresa pollock Darrell G.Schlom Eric S.Toberer james Analytis Ismaila Dabo Dean M.DeLongchamp Gregory A.Fiete Gregory M.Grason Geoffroy Hautier Yifei Mo Krishna Rajan Evan j.Reed Efrain Rodriguez Vladan Stevanovic jin Suntivich Katsuyo Thornton ji-Cheng Zhao Institute for Molecular Engineering University of ChicagoChicagoIL 60615USA Department of Materials Science and Engineering The Pennsylvania State UniversityUniversity ParkPA 16802USA Department of Physics University of CaliforniaBerkeleyBerkeleyCA 94720USA Department of Materials Science and Engineering University of Wisconsin-MadisonMadisonWI 53706USA Materials Department and Materials Research Laboratory University of CaliforniaSanta BarbaraCA 93106USA Department of Materials Science and Engineering Cornell UniversityIthacaNY 14853USA Department of Physics Colorado School of MinesGoldenCO 80401USA Materials Measurement Laboratory National Institute of Standards and TechnologyGaithersburgMD 20899USA Department of Physics University of Texas at AustinAustinTX 78712USA Department of Polymer Science and Engineering University of MassachusettsAmherstMA 01003USA Institute of Condensed Matter and Nanosciences UniversitéCatholique de Louvain1348 Louvain-la-NeuveBelgium Department of Materials Science and Engineering University of MarylandCollege ParkMD 20742USA Department of Materials Design and Innovation University of Buffalo–The State University of New YorkBuffaloNY 14260-5030USA Department of Materials Science and Engineering Stanford UniversityStanfordCA 94305USA Department of Chemistry and Biochemistry University of MarylandCollege ParkMD 20742USA Department of Metallurgical and Materials Engineering Colorado School of MinesGoldenCO 80401USA Department of Materials Science and Engineering University of MichiganAnn ArborMI 48109USA Department of Materials Science and Engineering The Ohio State UniversityColumbusOH 43210USA

The Materials Genome Initiative(MGI)advanced a new paradigm for materials discovery and design,namely that the pace of new materials deployment could be accelerated through complementary efforts in theory,computation,and *** with numerous successes,new challenges are inviting researchers to refocus the efforts and approaches that were originally inspired by the *** May 2017,the National Science Foundation sponsored the workshop“Advancing and Accelerating Materials Innovation Through the Synergistic Interaction among Computation,Experiment,and Theory:Opening New Frontiers”to review accomplishments that emerged from investments in science and infrastructure under the MGI,identify scientific opportunities in this new environment,examine how to effectively utilize new materials innovation infrastructure,and discuss challenges in achieving accelerated materials research through the seamless integration of experiment,computation,and *** article summarizes key findings from the workshop and provides perspectives that aim to guide the direction of future materials research and its translation into societal impacts.

关键词： utilize frontier accomplishment

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竖轴水轮发电机空气间隙动态监测方面的经验

水电站机电技术 1998年第4期21卷 71-75页

作者： G.B.pollock j.F.Lyles 陶志健加拿大安大略电力公司

直到最近以前,动态监测水轮发电机转子和定子之间的空气间隙还很不实际。既有成本效益,又有可靠性能的动态气隙监测设备只是近年才开发出来的。对气隙作动态监测的必要性,在最初是电厂希望尽量降低气隙事故所造成的灾难性后果。然而,事... 详细信息

直到最近以前,动态监测水轮发电机转子和定子之间的空气间隙还很不实际。既有成本效益,又有可靠性能的动态气隙监测设备只是近年才开发出来的。对气隙作动态监测的必要性,在最初是电厂希望尽量降低气隙事故所造成的灾难性后果。然而,事实证明对气隙进行连续监测是有效益的,它可以帮助我们测度水轮发电机的性能状况。气隙监测设备可提供转子和定子状况及发电机振动方面的有用资讯。管理人员要对机组维修时机和维修程度作出决断,而监测设备提供的数据正是决策过程的有力助手。

关键词：监测动态转子定子水轮发电机空气间隙

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先进高温合金单晶材料

先进高温合金单晶材料