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

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

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Sports compression garments improve resting markers of venous return and muscle blood flow in male basketball players

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journal of Sport and Health Science 2023年第4期12卷 513-522页

作者： Shane F.O'Riordan Rod McGregor Shona L.Halson david j.bishop james R.Broatch Institute for Health and Sport(iHeS) Victoria UniversityFootscrayVIC 3011Australia Department of Physiology Australian Institute of SportBruceACT 2617Australia Faculty of Health University of CanberraBruceACT 2617Australia School of Behavioural and Health Sciences Australian Catholic UniversityBanyoQLD 4014Australia

Background:The benefits associated with sports compression garments are thought to be closely related to enhanced blood ***,findings are equivocal,possibly due to heterogeneity in the techniques used for measuring blood flow,the garment types used,and the pressures *** study combined Doppler ultrasound and near-infrared spectroscopy technologies to provide the first comprehensive assessment of the effects of 3 sports compression garment types on markers of venous return and muscle blood flow at ***:Resting lower-limb blood flow measures(markers of venous return,muscle blood flow,and muscle oxygenation)of 22 elite,junior,male basketball players(age=17.2±0.9 years,mean±SD)were assessed in 4 separate conditions:no compression(CON),compression tights(TIGHTS),compression shorts(SHORTS),and compression socks(SOCKS).Markers of venous return(cross-sectional area,time-averaged mean and peak blood flow velocity,and venous blood flow)were measured via Doppler ultrasound at the popliteal and common femoral *** blood flow and muscle oxygenation were measured in the gastrocnemius medialis and vastus lateralis using near-infrared ***:Popliteal markers of venous return were higher in TIGHTS compared to CON(p<0.01)and SHORTS(p<0.01),with SOCKS values higher compared with CON(p<0.05).Common femoral vein markers of venous return were higher for all conditions compared to CON(p<0.05),with TIGHTS values also higher compared to SOCKS(p<0.05).Gastrocnemius medialis blood flow was higher for TIGHTS compared to CON(p=0.000),SOCKS(p=0.012),and SHORTS(p=0.000),with SOCKS higher compared to SHORTS(p=0.046).Vastus lateralis blood flow was higher for TIGHTS compared to CON(p=0.028)and SOCKS(p=0.019),with SHORTS also higher compared to CON(p=0.012)and SOCKS(p=0.005).Gastrocnemius medialis oxygenation was higher for TIGHTS compared to CON(p=0.003),SOCKS(p=0.033),and SHORTS(p=0.003),with SOCKS higher compared to CON(p=0.044)and SHORTS(p=0.032).Va

关键词： Arterial perfusion Lower-limb compression Pressure Venous flow

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A system for probing Casimir energy corrections to the condensation energy

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Microsystems & Nanoengineering 2020年第1期6卷 1-12页

作者： Diego Perez-Morelo Alexander Stange Richard W.Lally Lawrence K.Barrett Matthias Imboden Abhishek Som david K.Campbell Vladimir A.Aksyuk david j.bishop Department of ECE Boston UniversityBostonMA 02215USA Physical Measurement Laboratory National Institute of Standards and TechnologyGaithersburgMD 20899USA Institute for Research in Electronics and Applied Physics&Maryland NanoCenter University of MarylandCollege ParkMD 20742USA Division of MSE Boston UniversityBostonMA 02215 USA 54K-MEMS Sarl Rue des Lavannes 172072 St BlaiseSwitzerland Department of Physics Boston UniversityBostonMA 02215USA Department of ME Boston UniversityBostonMA 02215USA Department of BME Boston UniversityBostonMA 02215USA

In this article,we present a nanoelectromechanical system(NEMS)designed to detect changes in the Casimir *** Casimir effect is a result of the appearance of quantum fluctuations in an electromagnetic *** experiments have used nano-or microscale parallel plate capacitors to detect the Casimir force by measuring the small attractive force these fluctuations exert between the two *** this new set of experiments,we aim to directly detect the shifts in the Casimir energy in a vacuum due to the presence of the metallic parallel plates,one of which is a superconductor.A change in the Casimir energy of this configuration is predicted to shift the superconducting transition temperature(T_(c))because of the interaction between it and the superconducting condensation *** our experiment,we take a superconducting film,carefully measure its transition temperature,bring a conducting plate close to the film,create a Casimir cavity,and then measure the transition temperature *** expected shifts are smaller than the normal shifts one sees in cycling superconducting films to cryogenic temperatures,so using a NEMS resonator in situ is the only practical way to obtain accurate,reproducible *** a thin Pb film and opposing Au surface,we observe no shift in T_(c)>12µK down to a minimum spacing of~70 nm at zero applied magnetic field.

关键词： cycling energy film

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Analysis of a Casimir-driven parametric amplifier with resilience to Casimir pull-in for MEMS single-point magnetic gradiometry

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Microsystems & Nanoengineering 2021年第5期7卷 183-193页

作者： josh javor Zhancheng Yao Matthias Imboden david K.Campbell david j.bishop Department of Mechanical Engineering Boston UniversityBostonMA 02215USA Division of Materials Science and Engineering Boston UniversityBostonMA 02215USA K-MEMS St.BlaiseSwitzerland Department of Electrical Engineering Boston UniversityBostonMA 02215USA Department of Physics Boston UniversityBostonMA 02215USA Department of Biomedical Engineering Boston UniversityBostonMA 02215USA

The Casimir force,a quantum mechanical effect,has been observed in several microelectromechanical system(MEMS)*** to its extreme sensitivity to the separation of two objects,the Casimir force has been proposed as an excellent avenue for quantum *** application,however,is challenging due to attractive forces leading to stiction and device failure,called Casimir *** this work,we design and simulate a Casimir-driven metrology platform,where a time-delay-based parametric amplification technique is developed to achieve a steady-state and avoid *** apply the design to the detection of weak,low-frequency,gradient magnetic fields similar to those emanating from ionic currents in the heart and *** parameters are selected from recent experimental platforms developed for Casimir metrology and magnetic gradiometry,both on MEMS *** a MEMS offers many advantages to such an application,the detected signal must typically be at the resonant frequency of the device,with diminished sensitivity in the low frequency regime of biomagnetic *** a Casimir-driven parametric amplifier,we report a 10,000-fold improvement in the best-case resolution of MEMS single-point gradiometers,with a maximum sensitivity of 6 Hz/(pT/cm)at 1 *** development of the proposed design has the potential to revolutionize metrology and may specifically enable the unshielded monitoring of biomagnetic fields in ambient conditions.

关键词： parametric Casimir apply

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Probing the subcellular nanostructure of engineered human cardiomyocytes in 3D tissue

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Microsystems & Nanoengineering 2021年第1期7卷 133-140页

作者： josh javor jourdan K.Ewoldt Paige E.Cloonan Anant Chopra Rebeccah j.Luu Guillaume Freychet Mikhail Zhernenkov Karl Ludwig jonathan G.Seidman Christine E.Seidman Christopher S.Chen david j.bishop Department of Mechanical Engineering Boston UniversityBostonMA 02215USA Department of Biomedical Engineering Boston UniversityBostonMA 02215USA SMI Beamline 12-ID Brookhaven National LaboratoryUptonNY 11973USA Department of Physics Boston UniversityBostonMA 02215USA Division of Materials Science Boston UniversityBostonMassachusetts 02215USA Department of Genetics Harvard Medical SchoolBostonMA 02215USA Department of Electrical Engineering Boston UniversityBostonMA 02215USA

The structural and functional maturation of human induced pluripotent stem cell-derived cardiomyocytes(hiPSC-CMs)is essential for pharmaceutical testing,disease modeling,and ultimately therapeutic *** 3D-tissue platforms have improved the functional maturation of hiPSC-CMs,but probing cardiac contractile properties in a 3D environment remains challenging,especially at depth and in live *** small-angle X-ray scattering(SAXS)imaging,we show that hiPSC-CMs matured and examined in a 3D environment exhibit a periodic spatial arrangement of the myofilament lattice,which has not been previously detected in *** contractile force is found to correlate with both the scattering intensity(R^(2)=0.44)and lattice spacing(R^(2)=0.46).The scattering intensity also correlates with lattice spacing(R^(2)=0.81),suggestive of lower noise in our structural measurement than in the functional ***,we observed decreased myofilament ordering in tissues with a myofilament mutation known to lead to hypertrophic cardiomyopathy(HCM).Our results highlight the progress of human cardiac tissue engineering and enable unprecedented study of structural maturation in hiPSC-CMs.

关键词： cardiac cardiomyocytes spacing

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Mentors Expressing What They Value Through Their Writings: Emphasizing the Person in Mathematics

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ECNU Review of Education 2021年第2期4卷 230-240页

作者： Wee Tiong Seah Qiaoping Zhang Alan j.bishop The University of Melbourne The Education University of Hong Kong Monash University

Purpose:This article identifies an issue in mathematics education,that is,the perceived lack of emphasis in recent times of the roles that the"person"plays in the development of *** purpose is to exami ne how values/valui ng might con tribute to addressi ng the ***/Approach/Methods:“Data”were collected from several purposeful conversations among the three *** conversations were audio-recorded and *** transcript was then subjected to content analysis to identify ***:The data analysis yielded two novel approaches to raising learners'awareness of the humanness of *** would be to reframe the values that are operationalized when mathematics is taught and learnt,as processes of valuing which teachers and students engage in,*** sec ond approach would be to ack no wledge that writers of mathematics/mathematicia ns are not simply prese nting kn owledge but are also acti ng as men tors conv eying and transmitting messages about the ***/Value:The invoIvement of the"person" in the development of mathematics is not new knowledge,though it can be made more visible in mathematics *** article identifies two approaches-valuing and mentoring-which are novel in that they are already part of the pedagogical process and thus,accessible.

关键词： Mathematics mentoring values valuing

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Modular next generation fast-neutron detector for portal monitoring

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Nuclear Science and Techniques 2022年第1期33卷 140-148页

作者： E.Aboud S.Ahn G.V.Rogachev V.E.johnson j.bishop G.Christian E.Koshchiy C.E.Parker D.P.Scriven Cyclotron Institute Texas A&M UniversityCollege StationTX 77843USA Department of Physics and Astronomy Texas A&M UniversityCollege StationTX 77843USA Department of Statistics Texas A&M UniversityCollege StationTX 77843USA

Nuclear nonproliferation is of critical importance for global *** fissile materials including highly enriched uranium and weapons-grade plutonium are especially important to *** interrogation techniques may result in much better sensitivity but are difficult with conventional portal monitors that rely on detecting thermal ***,most conventional portal monitoring systems rely on ^(3)He,which has a finite and continually decreasing *** designing a highly segmented array of organic scintillators,we posit that we can accurately and quickly identify fissile materials,including weapons-grade plutonium and highly enriched uranium,being *** propose a new design for a fast-neutron detector that overcomes the limitations of the current generation of portal ***6 simulations have been performed in conjunction with the UMPBT statistical model to determine the sensitivity limitations of the proposed *** suggest that the proposed detector may be 10 times more efficient than current-generation thermal neutron detectors and may be able to positively identify a 81 mg 235U source in as little as 192 seconds utilizing active interrogation techniques.

关键词： Fast-neutron detection Portal monitoring Nonproliferation

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中北海西部蔡希斯坦群蒸发岩之上重力驱动的薄次拉伸:计算机辅助剖面复原技术的应用

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国外油气勘探 1996年第2期8卷 131-143,262页

作者： Daniel j.bishop 蔡伟石油物探学校

正断层作用和盐构造作用对北海中生代和第三纪地层的沉积及随后的变形起着重要的控制作用。除了先前证明了的盐撤离、溶解和差异沉积负裁等机理之外,还认识到了倾斜盐层上重力驱动薄皮拉伸对北海盆地的发育起着重要的作用。工业用剖面... 详细信息

正断层作用和盐构造作用对北海中生代和第三纪地层的沉积及随后的变形起着重要的控制作用。除了先前证明了的盐撤离、溶解和差异沉积负裁等机理之外,还认识到了倾斜盐层上重力驱动薄皮拉伸对北海盆地的发育起着重要的作用。工业用剖面复原软件被用来简化由中北海西部的一个解释过的区域数据库所选择的地震剖面的深度转换、复原和脱压实,并能改善解释精度,用图示并定量地描述与盐有关的拉伸。本研究的结果表明:蔡希斯坦群蒸发岩是于二叠纪时期沉积在一个浅凹盆地中的。二叠系透镜体是由蒸发岩之上的向斜盆地和地堑中的局部沉积作用形成的。当可流动的盐充填到背斜核中时,层状的盐发生褶皱。自早侏罗世以来,与裂谷期后沉降有关的区域性掀斜和沉积负荷的增加,致使异地的中生代和第三纪地层因流动盐层之上的重力扩张而拉伸,它使得异地岩体与下伏原地的晚古生界岩体之间产生滑离。上凹的铲状正断层向下消失在盐层中,向上伸展到上覆盖层层序中,并且在各个地质时代活动,造成异体岩体内地层变厚和褶皱。反向和同向正断层发育,生成复杂的向上分支的断层体系。从图上看,铲状断层呈曲线雁行状排列,由转换冲断层连接。断层一般宽3～7km,厚2～3km,长7～10km。侏罗纪—第三纪期间,盐运动是由盖层的活动性拉伸驱动的,导致盐充填到由断块旋转所产生的可能空间中。因此,盐隆起就出现在拉伸位置的下方。铲状断层的倾向通常与盐底面的倾向相同,尽管还有一些较大的反向区域性断层。在拉伸期间,区域倾斜增加到5°左右。它对盐层上的动力驱动拉伸来说是足够了。已出现了约6%的总拉伸。中北海西部已证实的重力驱动的薄皮拉伸是一种在北海盆地别的地方也能识别出的一种现象,并可与安哥拉近海、巴西、Nova Scotia和墨西哥湾已证实的类似现象相对比。

关键词：剖面复原重力拉张构造北海 CAD

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Application of laser scanning for rock mass characterization and discrete fracture network generation in an underground limestone mine

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International journal of Mining Science and Technology 2019年第1期29卷 131-137页

作者： juan j.Monsalve jon Baggett Richard bishop Nino Ripepi Mining and Minerals Department Virginia Polytechnic Institute&State University

Terrestrial laser scanning(TLS) is a useful technology for rock mass characterization. A laser scanner produces a massive point cloud of a scanned area, such as an exposed rock surface in an underground tunnel,with millimeter precision. The density of the point cloud depends on several parameters from both the TLS operational conditions and the specifications of the project, such as the resolution and the quality of the laser scan, the section of the tunnel, the distance between scanning stations, and the purpose of the scans. One purpose of the scan can be to characterize the rock mass and statistically analyze the discontinuities that compose it for further discontinuous modeling. In these instances, additional data processing and a detailed analysis should be performed on the point cloud to extract the parameters to define a discrete fracture network(DFN) for each discontinuity set. I-site studio is a point cloud processing software that allows users to edit and process laser scans. This software contains a set of geotechnical analysis tools that assist engineers during the structural mapping process, allowing for greater and more representative data regarding the structural information of the rock mass, which may be used for generating DFNs. This paper presents the procedures used during a laser scan for characterizing discontinuities in an underground limestone mine and the results of the scan as applied to the generation of DFNs for further discontinuous modeling.

关键词： Rock mass characterization Laser scanning Discrete fracture network I-site studio

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Room Temperature Sol-Gel Fabrication and Functionalization for Sensor Applications

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Photonic Sensors 2013年第2期3卷 168-177页

作者： George HUYANG john CANNING Ingemar PETERMANN david bishop Andrew McDONAGH Maxwell j. CROSSLEY School of Chemistry The University of Sydney NSW 2006 Australia Interdisciplinary Photonic Laboratories (iPL) School of Chemistry 222 Madsen Building F09 The University of Sydney NSW 2006 Australia University of Technology Sydney Broadway NSW 200 7 Australia

The structure and physical properties of a thin titania sol-gel layer prepared on silicon and silica surfaces were examined. Spectroscopic （FTIR, UV-VIS spectroscopy）, refractive index （ellipsometry） and microscopic （light microscopy and SEM/EDS） tools were used to examine both chemical uniformity and physical uniformity of the sol-gel glass layers. The conditions for the fabrication of uniform layers were established, and room temperature dopant incorporation was examined. The absorption bands of porphyrin-containing titania sol-gel layers were characterized. By addition of a metal salt to the titania layer, it was possible to metallate the free-base porphyrin within and change the UV-VIS absorbance of the porphyrin, the basis of metal detection using porphyrins. The metalloporphyrins were detected by localized laser ablation inductive coupled mass spectroscopy （LA-ICP-MS）, indicating fairly uniform distribution of metals across the titania surface.

关键词： Sol-gel titania titanium dioxide evanescent field sensor organic compound spectroscopy microscopy surface functionalization ablation inductive coupled mass spectroscopy

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