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Sample records for resonance force microscope

  1. Magnetic Resonance Force Microscope Development

    Energy Technology Data Exchange (ETDEWEB)

    Hammel, P.C.; Zhang, Z.; Suh, B.J.; Roukes, M.L.; Midzor, M.; Wigen, P.E.; Childress, J.R.

    1999-06-03

    Our objectives were to develop the Magnetic Resonance Force Microscope (MRFM) into an instrument capable of scientific studies of buried structures in technologically and scientifically important electronic materials such as magnetic multilayer materials. This work resulted in the successful demonstration of MRFM-detected ferromagnetic resonance (FMR) as a microscopic characterization tool for thin magnetic films. Strong FMR spectra obtained from microscopic Co thin films (500 and 1000 angstroms thick and 40 x 200 microns in lateral extent) allowed us to observe variations in sample inhomogeneity and magnetic anisotropy field. We demonstrated lateral imaging in microscopic FMR for the first time using a novel approach employing a spatially selective local field generated by a small magnetically polarized spherical crystallite of yttrium iron garnet. These successful applications of the MRFM in materials studies provided the basis for our successful proposal to DOE/BES to employ the MRF M in studies of buried interfaces in magnetic materials.

  2. Microscopic FMR Using Magnetic Resonance Force Microscopy

    Science.gov (United States)

    Zhang, Z.; Hammel, P. C.; Wigen, P. E.

    1996-03-01

    Magnetic resonance force microscopy (MRFM) is a new 3-D imaging technique with ultra-high spatial resolution. This technique, discussed primarily in the context of nuclear magnetic resonance, can also be applied as a microscopic ferromagnetic resonance probe to investigate the distributions of magnetic anisotropy and magnetic exchange interactions within magnetic materials (for example, magnetic multilayer systems). We report the first MRFM experiment on a single crystal Yittrium Iron Garnet film. A non-resonance mode and a family of magneto-static modes were observed in the MRFM spectra. The non-resonance mode is due to the response of the sample magnetization to the applied, time dependent bias field. This will be the main noise source when a magnet is mounted on the cantilever, an arrangement which is necessary in order to perform 3-D imaging in MRFM. The behavior of the magneto-static modes is in qualitative accord with theoretical expectations. The MRFM signal intensity is so large that the experiment is performed under ambient pressure instead of vacuum to reduce the response of the detector (cantilever). This indicates that MRFM will allow micron or sub-micron spatial resolution in studies of a wide variety of magnetic materials.

  3. Resonant difference-frequency atomic force ultrasonic microscope

    Science.gov (United States)

    Cantrell, John H. (Inventor); Cantrell, Sean A. (Inventor)

    2010-01-01

    A scanning probe microscope and methodology called resonant difference-frequency atomic force ultrasonic microscopy (RDF-AFUM), employs an ultrasonic wave launched from the bottom of a sample while the cantilever of an atomic force microscope, driven at a frequency differing from the ultrasonic frequency by one of the contact resonance frequencies of the cantilever, engages the sample top surface. The nonlinear mixing of the oscillating cantilever and the ultrasonic wave in the region defined by the cantilever tip-sample surface interaction force generates difference-frequency oscillations at the cantilever contact resonance. The resonance-enhanced difference-frequency signals are used to create images of nanoscale near-surface and subsurface features.

  4. Atomic force microscope characterization of a resonating nanocantilever

    DEFF Research Database (Denmark)

    Abadal, G.; Davis, Zachary James; Borrise, X.

    2003-01-01

    An atomic force microscope (AFM) is used as a nanometer-scale resolution tool for the characterization of the electromechanical behaviour of a resonant cantilever-based mass sensor. The cantilever is actuated electrostatically by applying DC and AC voltages from a driver electrode placed closely...... and of the oscillation amplitude on the frequency of the AC voltage is measured by this technique and the results are fitted by a simple non-linear electromechanical model. (C) 2003 Elsevier Science B.V. All rights reserved....

  5. The magnetic resonance force microscope: A new microscopic probe of magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Hammel, P.C.; Zhang, Z. [Los Alamos National Lab., NM (United States); Midzor, M.; Roukes, M.L. [California Inst. of Tech., Pasadena, CA (United States); Wigen, P.E. [Ohio State Univ., Columbus, OH (United States); Childress, J.R. [Univ. of Florida, Gainesville, FL (United States)

    1997-08-06

    The magnetic resonance force microscope (MRFM) marries the techniques of magnetic resonance imaging (MRI) and atomic force microscopy (AFM), to produce a three-dimensional imaging instrument with high, potentially atomic-scale, resolution. The principle of the MRFM has been successfully demonstrated in numerous experiments. By virtue of its unique capabilities the MRFM shows promise to make important contributions in fields ranging from three-dimensional materials characterization to bio-molecular structure determination. Here the authors focus on its application to the characterization and study of layered magnetic materials; the ability to illuminate the properties of buried interfaces in such materials is a particularly important goal. While sensitivity and spatial resolution are currently still far from their theoretical limits, they are nonetheless comparable to or superior to that achievable in conventional MRI. Further improvement of the MRFM will involve operation at lower temperature, application of larger field gradients, introduction of advanced mechanical resonators and improved reduction of the spurious coupling when the magnet is on the resonator.

  6. The electrically detected magnetic resonance microscope: combining conductive atomic force microscopy with electrically detected magnetic resonance.

    Science.gov (United States)

    Klein, Konrad; Hauer, Benedikt; Stoib, Benedikt; Trautwein, Markus; Matich, Sonja; Huebl, Hans; Astakhov, Oleksandr; Finger, Friedhelm; Bittl, Robert; Stutzmann, Martin; Brandt, Martin S

    2013-10-01

    We present the design and implementation of a scanning probe microscope, which combines electrically detected magnetic resonance (EDMR) and (photo-)conductive atomic force microscopy ((p)cAFM). The integration of a 3-loop 2-gap X-band microwave resonator into an AFM allows the use of conductive AFM tips as a movable contact for EDMR experiments. The optical readout of the AFM cantilever is based on an infrared laser to avoid disturbances of current measurements by absorption of straylight of the detection laser. Using amorphous silicon thin film samples with varying defect densities, the capability to detect a spatial EDMR contrast is demonstrated. Resonant current changes as low as 20 fA can be detected, allowing the method to realize a spin sensitivity of 8×10(6)spins/√Hz at room temperature.

  7. Cryogenic positioning and alignment with micrometer precision in a magnetic resonance force microscope

    Science.gov (United States)

    Isaac, Corinne E.; Curley, Elizabeth A.; Nasr, Paméla T.; Nguyen, Hoang L.; Marohn, John A.

    2018-01-01

    Aligning a microcantilever to an area of interest on a sample is a critical step in many scanning probe microscopy experiments, particularly those carried out on devices and rare, precious samples. We report a series of protocols that rapidly and reproducibly align a high-compliance microcantilever to a resonance frequency while laterally scanning the tip to map the sample substrate through electrostatic interactions of the substrate with the cantilever. We demonstrate that when operating a cantilever a few micrometers from the sample surface, large shifts in the cantilever resonance frequency are present near the edges of a voltage-biased sample electrode. Surprisingly, these "edge-finder" frequency shifts are retained when the electrode is coated with a polymer film and a ˜10 nm thick metallic ground plane. The second series of methods, applicable to any scanning probe microscopy experiment, integrate a single-optical fiber to image line scans of the sample surface. The microscope modifications required for these methods are straightforward to implement, provide reliable micrometer-scale positioning, and decrease the experimental setup time from days to hours in a vacuum, cryogenic magnetic resonance force microscope.

  8. Atomic Force Microscope

    Energy Technology Data Exchange (ETDEWEB)

    Day, R.D.; Russell, P.E.

    1988-12-01

    The Atomic Force Microscope (AFM) is a recently developed instrument that has achieved atomic resolution imaging of both conducting and non- conducting surfaces. Because the AFM is in the early stages of development, and because of the difficulty of building the instrument, it is currently in use in fewer than ten laboratories worldwide. It promises to be a valuable tool for obtaining information about engineering surfaces and aiding the .study of precision fabrication processes. This paper gives an overview of AFM technology and presents plans to build an instrument designed to look at engineering surfaces.

  9. Spin microscope based on optically detected magnetic resonance

    Science.gov (United States)

    Berman, Gennady P.; Chernobrod, Boris M.

    2007-12-11

    The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

  10. A Compact Vertical Scanner for Atomic Force Microscopes

    OpenAIRE

    Jae Hong Park; Jaesool Shim; Dong-Yeon Lee

    2010-01-01

    A compact vertical scanner for an atomic force microscope (AFM) is developed. The vertical scanner is designed to have no interference with the optical microscope for viewing the cantilever. The theoretical stiffness and resonance of the scanner are derived and verified via finite element analysis. An optimal design process that maximizes the resonance frequency is performed. To evaluate the scanner’s performance, experiments are performed to evaluate the travel range, resonance frequency, an...

  11. Photon scanning tunneling microscope in combination with a force microscope

    NARCIS (Netherlands)

    Moers, M.H.P.; Moers, M.H.P.; Tack, R.G.; van Hulst, N.F.; Bölger, B.; Bölger, B.

    1994-01-01

    The simultaneous operation of a photon scanning tunneling microscope with an atomic force microscope is presented. The use of standard atomic force silicon nitride cantilevers as near-field optical probes offers the possibility to combine the two methods. Vertical forces and torsion are detected

  12. Atomic Force Microscope Mediated Chromatography

    Science.gov (United States)

    Anderson, Mark S.

    2013-01-01

    The atomic force microscope (AFM) is used to inject a sample, provide shear-driven liquid flow over a functionalized substrate, and detect separated components. This is demonstrated using lipophilic dyes and normal phase chromatography. A significant reduction in both size and separation time scales is achieved with a 25-micron-length column scale, and one-second separation times. The approach has general applications to trace chemical and microfluidic analysis. The AFM is now a common tool for ultra-microscopy and nanotechnology. It has also been demonstrated to provide a number of microfluidic functions necessary for miniaturized chromatography. These include injection of sub-femtoliter samples, fluidic switching, and sheardriven pumping. The AFM probe tip can be used to selectively remove surface layers for subsequent microchemical analysis using infrared and tip-enhanced Raman spectroscopy. With its ability to image individual atoms, the AFM is a remarkably sensitive detector that can be used to detect separated components. These diverse functional components of microfluidic manipulation have been combined in this work to demonstrate AFM mediated chromatography. AFM mediated chromatography uses channel-less, shear-driven pumping. This is demonstrated with a thin, aluminum oxide substrate and a non-polar solvent system to separate a mixture of lipophilic dyes. In conventional chromatographic terms, this is analogous to thin-layer chromatography using normal phase alumina substrate with sheardriven pumping provided by the AFM tip-cantilever mechanism. The AFM detection of separated components is accomplished by exploiting the variation in the localized friction of the separated components. The AFM tip-cantilever provides the mechanism for producing shear-induced flows and rapid pumping. Shear-driven chromatography (SDC) is a relatively new concept that overcomes the speed and miniaturization limitations of conventional liquid chromatography. SDC is based on a

  13. A Compact Vertical Scanner for Atomic Force Microscopes

    Directory of Open Access Journals (Sweden)

    Jae Hong Park

    2010-11-01

    Full Text Available A compact vertical scanner for an atomic force microscope (AFM is developed. The vertical scanner is designed to have no interference with the optical microscope for viewing the cantilever. The theoretical stiffness and resonance of the scanner are derived and verified via finite element analysis. An optimal design process that maximizes the resonance frequency is performed. To evaluate the scanner’s performance, experiments are performed to evaluate the travel range, resonance frequency, and feedback noise level. In addition, an AFM image using the proposed vertical scanner is generated.

  14. A Magnetic Resonance Force Microscope

    National Research Council Canada - National Science Library

    Marohn, John

    2003-01-01

    Key technologies required to bring the instrument to market with sensitivity to a few thousand protons were demonstrated including a novel cryogenic coarse approach mechanism and the first-ever batch...

  15. Magnetic Resonance Force Microscopy System

    Data.gov (United States)

    Federal Laboratory Consortium — The Magnetic Resonance Force Microscopy (MRFM) system, developed by ARL, is the world's most sensitive nuclear magnetic resonance (NMR) spectroscopic analysis tool,...

  16. Atomic force microscope featuring an integrated optical microscope

    NARCIS (Netherlands)

    Putman, C.A.J.; Putman, Constant A.J.; de Grooth, B.G.; van Hulst, N.F.; Greve, Jan

    1992-01-01

    The atomic force microscope (AFM) is used to image the surface of both conductors and nonconductors. Biological specimens constitute a large group of nonconductors. A disadvantage of most AFM's is the fact that relatively large areas of the sample surface have to be scanned to pinpoint a biological

  17. Measuring Forces between Oxide Surfaces Using the Atomic Force Microscope

    DEFF Research Database (Denmark)

    Pedersen, Henrik Guldberg; Høj, Jakob Weiland

    1996-01-01

    The interactions between colloidal particles play a major role in processing of ceramics, especially in casting processes. With the Atomic Force Microscope (AFM) it is possible to measure the inter-action force between a small oxide particle (a few micron) and a surface as function of surface...

  18. Micromechanical Resonator Driven by Radiation Pressure Force.

    Science.gov (United States)

    Boales, Joseph A; Mateen, Farrukh; Mohanty, Pritiraj

    2017-11-22

    Radiation pressure exerted by light on any surface is the pressure generated by the momentum of impinging photons. The associated force - fundamentally, a quantum mechanical aspect of light - is usually too small to be useful, except in large-scale problems in astronomy and astrodynamics. In atomic and molecular optics, radiation pressure can be used to trap or cool atoms and ions. Use of radiation pressure on larger objects such as micromechanical resonators has been so far limited to its coupling to an acoustic mode, sideband cooling, or levitation of microscopic objects. In this Letter, we demonstrate direct actuation of a radio-frequency micromechanical plate-type resonator by the radiation pressure force generated by a standard laser diode at room temperature. Using two independent methods, the magnitude of the resonator's response to forcing by radiation pressure is found to be proportional to the intensity of the incident light.

  19. Atomic Force Microscope for Imaging and Spectroscopy

    Science.gov (United States)

    Pike, W. T.; Hecht, M. H.; Anderson, M. S.; Akiyama, T.; Gautsch, S.; deRooij, N. F.; Staufer, U.; Niedermann, Ph.; Howald, L.; Mueller, D.

    2000-01-01

    We have developed, built, and tested an atomic force microscope (AFM) for extraterrestrial applications incorporating a micromachined tip array to allow for probe replacement. It is part of a microscopy station originally intended for NASA's 2001 Mars lander to identify the size, distribution, and shape of Martian dust and soil particles. As well as imaging topographically down to nanometer resolution, this instrument can be used to reveal chemical information and perform infrared and Raman spectroscopy at unprecedented resolution.

  20. Calibrated atomic force microscope measurements of vickers hardness indentations and tip production and characterisation for scanning tunelling microscope

    DEFF Research Database (Denmark)

    Jensen, Carsten P.

    Calibrated atomic force microscope measurements of vickers hardness indentations and tip production and characterisation for scanning tunelling microscope......Calibrated atomic force microscope measurements of vickers hardness indentations and tip production and characterisation for scanning tunelling microscope...

  1. Nuclear magnetic resonance force microscopy at millikelvin temperatures

    NARCIS (Netherlands)

    Haan, Arthur Mattheus Johannes den

    2016-01-01

    Nuclear magnetic resonance force microscopy (MRFM) is a technique which combines magnetic resonance imaging (MRI) with scanning probe microscopy (SPM). The final goal is to develop this technique to such a level that the atomic structure of a virus or protein can be revealed by this microscope. This

  2. Atomic force microscopical and surface plasmon resonance spectroscopical investigation of sub-micrometer metal gratings generated by UV laser-based two-beam interference in Au-Ag bimetallic layers

    Energy Technology Data Exchange (ETDEWEB)

    Csete, M. [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dom ter 9 (Hungary)]. E-mail: mcsete@physx.u-szeged.hu; Kohazi-Kis, A. [Faculty of Mechanical Engineering and Automation, Kecskemet College, H-6000 Kecskemet, Izsaki str. 10 (Hungary); Vass, Cs. [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dom ter 9 (Hungary); Sipos, A. [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dom ter 9 (Hungary); Szekeres, G. [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dom ter 9 (Hungary); Deli, M. [Laboratory of Molecular Neurobiology, Institute of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, Temesvari Krt. 62, H-6726 Szeged (Hungary); Osvay, K. [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dom ter 9 (Hungary); Bor, Zs. [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dom ter 9 (Hungary)

    2007-07-31

    Metal films containing silver and gold layers having different thicknesses were evaporated on glass substrates. Two-beam interference technique was applied to irradiate the surfaces by the fourth harmonic of a pulsed mode Nd:YAG laser. The atomic force microscopical study showed that surface relief grating having a period of 900 nm corresponding to the interference pattern was developed on the metallic films. The modulation amplitude of the laser-induced gratings was increasable by enhancing the number of laser pulses at constant fluence, and a groove depth commensurable with the film thicknesses was generated at the average fluence of 39.5 mJ/cm{sup 2} on bimetallic layers. The surface structure was more regular, and the modulation amplitude was larger in case of bimetallic films containing thicker gold layers. The threshold fluences of the phase transitions were determined by numerical temperature model calculations for different metal layer compositions, and a good agreement was found between the calculated and experimentally observed threshold values. The division of the metal stripes into droplets and the development of holes were explained by the melting of the entire metal layers and by the vaporization of silver at higher fluences. The angle-dependent surface plasmon resonance spectroscopy realized in Kretschmann arrangement proved that the laser-induced grating formation was accompanied by the change in the optical thickness and by the modification of the structure of the bimetallic films. Broad side wings appeared on the resonance curves caused by grating-coupling in case of appropriate rotation angle and sufficiently large modulation depth of the grating's grooves, according to our calculations. The coupling on deep gratings developed on bimetallic films containing the thinnest gold layer and on monometallic silver films resulted in separated secondary resonance minimum development. The periodic adherence of native streptavidin on the metallic

  3. Polymerized LB Films Imaged with a Combined Atomic Force Microscope-Fluorescence Microscope

    NARCIS (Netherlands)

    Putman, C.A.J.; Putman, Constant A.J.; Hansma, Helen G.; Gaub, Hermann E.; Hansma, Paul K.

    1992-01-01

    The first results obtained with a new stand-alone atomic force microscope (AFM) integrated with a standard Zeiss optical fluorescence microscope are presented. The optical microscope allows location and selection of objects to be imaged with the high-resolution AFM. Furthermore, the combined

  4. Atomic force microscope with integrated optical microscope for biological applications

    NARCIS (Netherlands)

    Putman, Constant A.J.; Putman, C.A.J.; van der Werf, Kees; de Grooth, B.G.; van Hulst, N.F.; Segerink, Franciscus B.; Greve, Jan

    1992-01-01

    Since atomic force microscopy (AFM) is capable of imaging nonconducting surfaces, the technique holds great promises for high‐resolution imaging of biological specimens. A disadvantage of most AFMs is the fact that the relatively large sample surface has to be scanned multiple times to pinpoint a

  5. Microscopic derivation of electromagnetic force density in magnetic dielectric media

    NARCIS (Netherlands)

    Shevchenko, A.; Hoenders, B. J.

    2010-01-01

    Macroscopic force density imposed on a linear isotropic magnetic dielectric medium by an arbitrary electromagnetic field is derived by spatially averaging the microscopic Lorentz force density. The obtained expression differs from the commonly used expressions, but the energy-momentum tensor derived

  6. Interatomic force microscope and sample observing method therefor

    OpenAIRE

    YAMANAKA, K; Kolosov, Oleg; Ogiso, H; Sato, H.; Koda, T

    1994-01-01

    PURPOSE:To provide a measuring technology for interatomic microscope in which the irregular sample can be separated well from the frictional force. SOLUTION :An oscillating force applied laterally relatively between a sample 8 and a probe 4 Is provided. The sample 8 tilted laterally to excite bending orthogonal oscillation. The phase and the amplitude of the oscillation of the cantilever are detected.

  7. Collective light forces on atoms in resonators

    Energy Technology Data Exchange (ETDEWEB)

    Black, Adam T; Thompson, James K; Vuletic, Vladan [Department of Physics, MIT-Harvard Center for Ultracold Atoms, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2005-05-14

    We study resonator-induced light forces arising from cooperative atom-light interaction. For such collective processes, the force on the sample can be orders of magnitude larger than the sum of conventional light forces on individual atoms. Since resonator-induced light forces can be dissipative even when the incident light is far detuned from atomic transitions, they may be applicable to target particles with a complex level structure.

  8. Mechanochemistry Induced Using Force Exerted by a Functionalized Microscope Tip

    DEFF Research Database (Denmark)

    Zhang, Yajie; Wang, Yongfeng; Lü, Jing-Tao

    2017-01-01

    Atomic-scale mechanochemistry is realized from force exerted by a C60 -functionalized scanning tunneling microscope tip. Two conformers of tin phthalocyanine can be prepared on coinage-metal surfaces. A transition between these conformers is induced on Cu(111) and Ag(100). Density-functional calc......Atomic-scale mechanochemistry is realized from force exerted by a C60 -functionalized scanning tunneling microscope tip. Two conformers of tin phthalocyanine can be prepared on coinage-metal surfaces. A transition between these conformers is induced on Cu(111) and Ag(100). Density...

  9. Micromachined fountain pen for atomic force microscope-based nanopatterning

    NARCIS (Netherlands)

    Deladi, S.; Tas, Niels Roelof; Berenschot, Johan W.; Krijnen, Gijsbertus J.M.; de Boer, Meint J.; de Boer, J.H.; Péter, M.; Elwenspoek, Michael Curt

    2004-01-01

    We present a tool that can be used in standard atomic force microscope and that enables chemical, chemical/mechanical, or physical surface modification using continuous liquid supply. The device consists of a reservoir micromachined into the probe support that is connected to fluidic channels

  10. A new concept in magnetic force microscope cantilevers

    NARCIS (Netherlands)

    van den Bos, A.G.; van Dijk, A.C.J.; Heskamp, I.R.; Abelmann, Leon; Lodder, J.C.; Hadjipanayis, G.C.

    2001-01-01

    In this paper, a new design of dedicated magnetic force microscope (MFM) cantilever is presented. In this design, the cantilever and the magnetic tip are realized in an integrated manufacturing process. The use of silicon micromachining techniques enables batch fabrication of several hundred

  11. New approaches to atomic force microscope lithography on silicon

    DEFF Research Database (Denmark)

    Birkelund, Karen; Thomsen, Erik Vilain; Rasmussen, Jan Pihl

    1997-01-01

    We have investigated new approaches to the formation of conducting nanowires on crystalline silicon surfaces using atomic force microscope (AFM) lithography. To increase processing speed and reduce wear of the AFM tip, large-scale structures are formed with a direct laser write setup, while the AFM...

  12. Stitching Grid-wise Atomic Force Microscope Images

    DEFF Research Database (Denmark)

    Vestergaard, Mathias Zacho; Bengtson, Stefan Hein; Pedersen, Malte

    2016-01-01

    Atomic Force Microscopes (AFM) are able to capture images with a resolution in the nano metre scale. Due to this high resolution, the covered area per image is relatively small, which can be problematic when surveying a sample. A system able to stitch AFM images has been developed to solve this p...

  13. Fabrication of an all-metal atomic force microscope probe

    DEFF Research Database (Denmark)

    Rasmussen, Jan Pihl; Tang, Peter Torben; Hansen, Ole

    1997-01-01

    This paper presents a method for fabrication of an all-metal atomic force microscope probe (tip, cantilever and support) for optical read-out, using a combination of silicon micro-machining and electroforming. The paper describes the entire fabrication process for a nickel AFM-probe. In addition...

  14. Uncertainty quantification in nanomechanical measurements using the atomic force microscope

    Science.gov (United States)

    Ryan Wagner; Robert Moon; Jon Pratt; Gordon Shaw; Arvind Raman

    2011-01-01

    Quantifying uncertainty in measured properties of nanomaterials is a prerequisite for the manufacture of reliable nanoengineered materials and products. Yet, rigorous uncertainty quantification (UQ) is rarely applied for material property measurements with the atomic force microscope (AFM), a widely used instrument that can measure properties at nanometer scale...

  15. Investigations in high speed blanking: cutting forces and microscopic observations

    Directory of Open Access Journals (Sweden)

    Larue A.

    2010-06-01

    Full Text Available A new hopefull technique, called high speed blanking, has been investigated since few years. To understand the cutting process and how the tools have to be designed, this study is interrested in the cutting force measurement. A new cutting force measurement device has to be designed consider the industrial interest of such a study. The designed test bench induces a calibration process in order to stucy the cutting forces evolution. The paper is discussing the result that the peack load seems to decrease when the punch speed increases. Finally microscopic observations are made in order to find Adiabatic Shear Bands.

  16. Manipulation and soldering of carbon nanotubes using atomic force microscope

    Science.gov (United States)

    Kashiwase, Yuta; Ikeda, Takayuki; Oya, Takahide; Ogino, Toshio

    2008-09-01

    Manipulation of carbon nanotubes (CNTs) by an atomic force microscope (AFM) and soldering of CNTs using Fe oxide nanoparticles are described. We succeeded to separate a CNT bundle into two CNTs or CNT bundles, to move the separated CNT to a desirable position, and to bind it to another bundle. For the accurate manipulation, load of the AFM cantilever and frequency of the scan were carefully selected. We soldered two CNTs using an Fe oxide nanoparticle prepared from a ferritin molecule. The adhesion forces between the soldered CNTs were examined by an AFM and it was found that the CNTs were bound, though the binding force was not strong.

  17. Microscopic calculation of the restoring force for scissor isovector vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Nojarov, R.; Bochnacki, Z.; Faessler, A.

    1986-07-01

    The restoring force for scissor isovector vibrations is calculated microscopically with the wave functions of an axially symmetric Woods-Saxon potential from a density-dependent symmetry energy. The experimental energies of the low-lying magnetic dipole states in rare-earth nuclei are well reproduced. It is found that only outer particles, which contribute to the nuclear moment of inertia, take part in this collective vibration. They are about half of the total number of nucleons.

  18. Magnetic resonance force detection using a membrane resonator.

    Science.gov (United States)

    Scozzaro, N; Ruchotzke, W; Belding, A; Cardellino, J; Blomberg, E C; McCullian, B A; Bhallamudi, V P; Pelekhov, D V; Hammel, P C

    2016-10-01

    The availability of compact, low-cost magnetic resonance imaging instruments would further broaden the substantial impact of this technology. We report highly sensitive detection of magnetic resonance using low-stress silicon nitride (SiNx) membranes. We use these membranes as low-loss, high-frequency mechanical oscillators and find they are able to mechanically detect spin-dependent forces with high sensitivity enabling ultrasensitive magnetic resonance detection. The high force detection sensitivity stems from their high mechanical quality factor Q∼10(6)[1,2] combined with the low mass of the resonator. We use this excellent mechanical force sensitivity to detect the electron spin magnetic resonance using a SiNx membrane as a force detector. The demonstrated force sensitivity at 300K is 4fN/Hz, indicating a potential low temperature (4K) sensitivity of 25aN/Hz. Given their sensitivity, robust construction, large surface area and low cost, SiNx membranes can potentially serve as the central component of a compact room-temperature ESR and NMR instrument having spatial resolution superior to conventional approaches. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Modular apparatus for electrostatic actuation of common atomic force microscope cantilevers.

    Science.gov (United States)

    Long, Christian J; Cannara, Rachel J

    2015-07-01

    Piezoelectric actuation of atomic force microscope (AFM) cantilevers often suffers from spurious mechanical resonances in the loop between the signal driving the cantilever and the actual tip motion. These spurious resonances can reduce the accuracy of AFM measurements and in some cases completely obscure the cantilever response. To address these limitations, we developed a specialized AFM cantilever holder for electrostatic actuation of AFM cantilevers. The holder contains electrical contacts for the AFM cantilever chip, as well as an electrode (or electrodes) that may be precisely positioned with respect to the back of the cantilever. By controlling the voltages on the AFM cantilever and the actuation electrode(s), an electrostatic force is applied directly to the cantilever, providing a near-ideal transfer function from drive signal to tip motion. We demonstrate both static and dynamic actuations, achieved through the application of direct current and alternating current voltage schemes, respectively. As an example application, we explore contact resonance atomic force microscopy, which is a technique for measuring the mechanical properties of surfaces on the sub-micron length scale. Using multiple electrodes, we also show that the torsional resonances of the AFM cantilever may be excited electrostatically, opening the door for advanced dynamic lateral force measurements with improved accuracy and precision.

  20. Modular apparatus for electrostatic actuation of common atomic force microscope cantilevers

    Energy Technology Data Exchange (ETDEWEB)

    Long, Christian J., E-mail: christian.long@nist.gov [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Maryland Nanocenter, University of Maryland, College Park, Maryland 20742 (United States); Cannara, Rachel J. [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

    2015-07-15

    Piezoelectric actuation of atomic force microscope (AFM) cantilevers often suffers from spurious mechanical resonances in the loop between the signal driving the cantilever and the actual tip motion. These spurious resonances can reduce the accuracy of AFM measurements and in some cases completely obscure the cantilever response. To address these limitations, we developed a specialized AFM cantilever holder for electrostatic actuation of AFM cantilevers. The holder contains electrical contacts for the AFM cantilever chip, as well as an electrode (or electrodes) that may be precisely positioned with respect to the back of the cantilever. By controlling the voltages on the AFM cantilever and the actuation electrode(s), an electrostatic force is applied directly to the cantilever, providing a near-ideal transfer function from drive signal to tip motion. We demonstrate both static and dynamic actuations, achieved through the application of direct current and alternating current voltage schemes, respectively. As an example application, we explore contact resonance atomic force microscopy, which is a technique for measuring the mechanical properties of surfaces on the sub-micron length scale. Using multiple electrodes, we also show that the torsional resonances of the AFM cantilever may be excited electrostatically, opening the door for advanced dynamic lateral force measurements with improved accuracy and precision.

  1. Application of Tuning Fork Sensors for In-situ Studies of Dynamic Force Interactions Inside Scanning and Transmission Electron Microscopes

    Directory of Open Access Journals (Sweden)

    Jana ANDZANE

    2012-06-01

    Full Text Available Mechanical properties of nanoscale contacts have been probed in-situ by specially developed force sensor based on a quartz tuning fork resonator (TF. Additional control is provided by observation of process in scanning electron microscope (SEM and transmission electron microscope (TEM. A piezoelectric manipulator allows precise positioning of atomic force microscope (AFM probe in contact with another electrode and recording of the TF oscillation amplitude and phase while simultaneously visualizing the contact area in electron microscope. Electrostatic control of interaction between the electrodes is demonstrated during observation of the experiment in SEM. In the TEM system the TF sensor operated in shear force mode: Use of TEM allowed for direct control of separation between electrodes. New opportunities for in situ studies of nanomechanical systems using these instruments are discussed.DOI: http://dx.doi.org/10.5755/j01.ms.18.2.1927

  2. A versatile atomic force microscope integrated with a scanning electron microscope

    Science.gov (United States)

    Kreith, J.; Strunz, T.; Fantner, E. J.; Fantner, G. E.; Cordill, M. J.

    2017-05-01

    A versatile atomic force microscope (AFM), which can be installed in a scanning electron microscope (SEM), is introduced. The flexible design of the instrument enables correlated analysis for different experimental configurations, such as AFM imaging directly after nanoindentation in vacuum. In order to demonstrate the capabilities of the specially designed AFM installed inside a SEM, slip steps emanating around nanoindents in single crystalline brass were examined. This example showcases how the combination of AFM and SEM imaging can be utilized for quantitative dislocation analysis through the measurement of the slip step heights without the hindrance of oxide formation. Finally, an in situ nanoindentation technique is introduced, illustrating the use of AFM imaging during indentation experiments to examine plastic deformation occurring under the indenter tip. The mechanical indentation data are correlated to the SEM and AFM images to estimate the number of dislocations emitted to the surface.

  3. Athermalization in atomic force microscope based force spectroscopy using matched microstructure coupling.

    Science.gov (United States)

    Torun, H; Finkler, O; Degertekin, F L

    2009-07-01

    The authors describe a method for athermalization in atomic force microscope (AFM) based force spectroscopy applications using microstructures that thermomechanically match the AFM probes. The method uses a setup where the AFM probe is coupled with the matched structure and the displacements of both structures are read out simultaneously. The matched structure displaces with the AFM probe as temperature changes, thus the force applied to the sample can be kept constant without the need for a separate feedback loop for thermal drift compensation, and the differential signal can be used to cancel the shift in zero-force level of the AFM.

  4. Method for lateral force calibration in atomic force microscope using MEMS microforce sensor.

    Science.gov (United States)

    Dziekoński, Cezary; Dera, Wojciech; Jarząbek, Dariusz M

    2017-11-01

    In this paper we present a simple and direct method for the lateral force calibration constant determination. Our procedure does not require any knowledge about material or geometrical parameters of an investigated cantilever. We apply a commercially available microforce sensor with advanced electronics for direct measurement of the friction force applied by the cantilever's tip to a flat surface of the microforce sensor measuring beam. Due to the third law of dynamics, the friction force of the equal value tilts the AFM cantilever. Therefore, torsional (lateral force) signal is compared with the signal from the microforce sensor and the lateral force calibration constant is determined. The method is easy to perform and could be widely used for the lateral force calibration constant determination in many types of atomic force microscopes. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. High-speed force mapping on living cells with a small cantilever atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Braunsmann, Christoph; Seifert, Jan; Rheinlaender, Johannes; Schäffer, Tilman E., E-mail: Tilman.Schaeffer@uni-tuebingen [Institute of Applied Physics and LISA, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen (Germany)

    2014-07-15

    The imaging speed of the wide-spread force mapping mode for quantitative mechanical measurements on soft samples in liquid with the atomic force microscope (AFM) is limited by the bandwidth of the z-scanner and viscous drag forces on the cantilever. Here, we applied high-speed, large scan-range atomic force microscopy and small cantilevers to increase the speed of force mapping by ≈10−100 times. This allowed resolving dynamic processes on living mouse embryonic fibroblasts. Cytoskeleton reorganization during cell locomotion, growth of individual cytoskeleton fibers, cell blebbing, and the formation of endocytic pits in the cell membrane were observed. Increasing the force curve rate from 2 to 300 Hz increased the measured apparent Young's modulus of the cells by about 10 times, which facilitated force mapping measurements at high speed.

  6. Electron beam detection of a Nanotube Scanning Force Microscope.

    Science.gov (United States)

    Siria, Alessandro; Niguès, Antoine

    2017-09-14

    Atomic Force Microscopy (AFM) allows to probe matter at atomic scale by measuring the perturbation of a nanomechanical oscillator induced by near-field interaction forces. The quest to improve sensitivity and resolution of AFM forced the introduction of a new class of resonators with dimensions at the nanometer scale. In this context, nanotubes are the ultimate mechanical oscillators because of their one dimensional nature, small mass and almost perfect crystallinity. Coupled to the possibility of functionalisation, these properties make them the perfect candidates as ultra sensitive, on-demand force sensors. However their dimensions make the measurement of the mechanical properties a challenging task in particular when working in cavity free geometry at ambient temperature. By using a focused electron beam, we show that the mechanical response of nanotubes can be quantitatively measured while approaching to a surface sample. By coupling electron beam detection of individual nanotubes with a custom AFM we image the surface topography of a sample by continuously measuring the mechanical properties of the nanoresonators. The combination of very small size and mass together with the high resolution of the electron beam detection method offers unprecedented opportunities for the development of a new class of nanotube-based scanning force microscopy.

  7. Interlaboratory comparison of traceable atomic force microscope pitch measurements

    Science.gov (United States)

    Dixson, Ronald; Chernoff, Donald A.; Wang, Shihua; Vorburger, Theodore V.; Tan, Siew Leng; Orji, Ndubuisi G.; Fu, Joseph

    2010-06-01

    The National Institute of Standards and Technology (NIST), Advanced Surface Microscopy (ASM), and the National Metrology Centre (NMC) of the Agency for Science, Technology, and Research (A*STAR) in Singapore have completed a three-way interlaboratory comparison of traceable pitch measurements using atomic force microscopy (AFM). The specimen being used for this comparison is provided by ASM and consists of SiO2 lines having a 70 nm pitch patterned on a silicon substrate. NIST has a multifaceted program in atomic force microscope (AFM) dimensional metrology. One component of this effort is a custom in-house metrology AFM, called the calibrated AFM (C-AFM). The NIST C-AFM has displacement metrology for all three axes traceable to the 633 nm wavelength of the iodine-stabilized He-Ne laser - a recommended wavelength for realization of the SI (Système International d'Unités, or International System of Units) meter. NIST used the C-AFM to participate in this comparison. ASM used a commercially available AFM with an open-loop scanner, calibrated by a 144 nm pitch transfer standard. In a prior collaboration with Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute, ASM's transfer standard was calibrated using PTB's traceable optical diffractometry instrument. Thus, ASM's measurements are also traceable to the SI meter. NMC/A*STAR used a large scanning range metrological atomic force microscope (LRM-AFM). The LRM-AFM integrates an AFM scanning head into a nano-stage equipped with three built-in He-Ne laser interferometers so that its measurement related to the motion on all three axes is directly traceable to the SI meter. The measurements for this interlaboratory comparison have been completed and the results are in agreement within their expanded uncertainties and at the level of a few parts in 104.

  8. Operation of a scanning near field optical microscope in reflection in combination with a scanning force microscope

    NARCIS (Netherlands)

    van Hulst, N.F.; Moers, M.H.P.; Moers, M.H.P.; Noordman, O.F.J.; Noordman, O.F.J.; Faulkner, T.; Segerink, Franciscus B.; van der Werf, Kees; de Grooth, B.G.; Bölger, B.; Bölger, B.

    1992-01-01

    Images obtained with a scanning near field optical microscope (SNOM) operating in reflection are presented. We have obtained the first results with a SiN tip as optical probe. The instrument is simultaneously operated as a scanning force microscope (SFM). Moreover, the instrument incorporates an

  9. High-speed atomic force microscope based on an astigmatic detection system

    Science.gov (United States)

    Liao, H.-S.; Chen, Y.-H.; Ding, R.-F.; Huang, H.-F.; Wang, W.-M.; Hwu, E.-T.; Huang, K.-Y.; Chang, C.-S.; Hwang, I.-S.

    2014-10-01

    High-speed atomic force microscopy (HS-AFM) enables visualizing dynamic behaviors of biological molecules under physiological conditions at a temporal resolution of 1s or shorter. A small cantilever with a high resonance frequency is crucial in increasing the scan speed. However, detecting mechanical resonances of small cantilevers is technically challenging. In this study, we constructed an atomic force microscope using a digital versatile disc (DVD) pickup head to detect cantilever deflections. In addition, a flexure-guided scanner and a sinusoidal scan method were implemented. In this work, we imaged a grating sample in air by using a regular cantilever and a small cantilever with a resonance frequency of 5.5 MHz. Poor tracking was seen at the scan rate of 50 line/s when a cantilever for regular AFM imaging was used. Using a small cantilever at the scan rate of 100 line/s revealed no significant degradation in the topographic images. The results indicate that a smaller cantilever can achieve a higher scan rate and superior force sensitivity. This work shows the potential for using a DVD pickup head in future HS-AFM technology.

  10. The development of a novel electromagnetic force microscope

    CERN Document Server

    Windmill, J F C

    2002-01-01

    This thesis describes the development of a new type of Magnetic Force Microscope (MFM) probe based on a unique electromagnetic design. In addition the design, construction and testing of a new MFM system, complete in both hardware and software, is also described. The MFM allowed initial tests on prototypes of the new probe, and is to provide a base for future new probe integration. The microscope uses standard MFM micro-cantilever probes in static modes of imaging. A new computer hosted DSP control system, software, and its various interfaces with the MFM have been integrated into the system. The system has been tested using standard probes with various specimens and satisfactory results have been produced. A novel probe has been designed to replace the standard MFM magnetic coated tip with a field generated about a sub-micron aperture in a conducting film. The field from the new probe is modelled and its imaging capability investigated, with iterative designs analysed in this way. The practical construction ...

  11. High-speed atomic force microscope combined with single-molecule fluorescence microscope.

    Science.gov (United States)

    Fukuda, Shingo; Uchihashi, Takayuki; Iino, Ryota; Okazaki, Yasutaka; Yoshida, Masato; Igarashi, Kiyohiko; Ando, Toshio

    2013-07-01

    High-speed atomic force microscopy (HS-AFM) and total internal reflection fluorescence microscopy (TIRFM) have mutually complementary capabilities. Here, we report techniques to combine these microscopy systems so that both microscopy capabilities can be simultaneously used in the full extent. To combine the two systems, we have developed a tip-scan type HS-AFM instrument equipped with a device by which the laser beam from the optical lever detector can track the cantilever motion in the X- and Y-directions. This stand-alone HS-AFM system is mounted on an inverted optical microscope stage with a wide-area scanner. The capability of this combined system is demonstrated by simultaneous HS-AFM∕TIRFM imaging of chitinase A moving on a chitin crystalline fiber and myosin V walking on an actin filament.

  12. Photothermal excitation setup for a modified commercial atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Adam, Holger; Rode, Sebastian; Schreiber, Martin; Kühnle, Angelika, E-mail: kuehnle@uni-mainz.de [Institute of Physical Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55099 Mainz (Germany); Kobayashi, Kei; Yamada, Hirofumi [Department of Electronic Science and Engineering, Kyoto University, Katsura, Nishikyo, Kyoto 615-8510 (Japan)

    2014-02-15

    High-resolution imaging in liquids using frequency modulation atomic force microscopy is known to suffer from additional peaks in the resonance spectrum that are unrelated to the cantilever resonance. These unwanted peaks are caused by acoustic modes of the liquid and the setup arising from the indirect oscillation excitation by a piezoelectric transducer. Photothermal excitation has been identified as a suitable method for exciting the cantilever in a direct manner. Here, we present a simple design for implementing photothermal excitation in a modified Multimode scan head from Bruker. Our approach is based on adding a few components only to keep the modifications as simple as possible and to maintain the low noise level of the original setup with a typical deflection noise density of about 15 fm/√(Hz) measured in aqueous solution. The success of the modification is illustrated by a comparison of the resonance spectra obtained with piezoelectric and photothermal excitation. The performance of the systems is demonstrated by presenting high-resolution images on bare calcite in liquid as well as organic adsorbates (Alizarin Red S) on calcite with simultaneous atomic resolution of the underlying calcite substrate.

  13. Spring constant calibration of atomic force microscope cantilevers of arbitrary shape

    Energy Technology Data Exchange (ETDEWEB)

    Sader, John E. [Department of Mathematics and Statistics, University of Melbourne, Victoria 3010 (Australia); Kavli Nanoscience Institute and Department of Physics, California Institute of Technology, Pasadena, California 91125 (United States); Sanelli, Julian A.; Adamson, Brian D.; Bieske, Evan J. [School of Chemistry, University of Melbourne, Victoria 3010 (Australia); Monty, Jason P.; Marusic, Ivan [Department of Mechanical Engineering, University of Melbourne, Victoria 3010 (Australia); Wei Xingzhan; Mulvaney, Paul [School of Chemistry, University of Melbourne, Victoria 3010 (Australia); Bio21 Institute, University of Melbourne, Victoria 3010 (Australia); Crawford, Simon A. [School of Botany, University of Melbourne, Victoria 3010 (Australia); Friend, James R. [Melbourne Centre for Nanofabrication, Clayton, Victoria 3800 (Australia); MicroNanophysics Research Laboratory, RMIT University, Melbourne, Victoria 3001 (Australia)

    2012-10-15

    The spring constant of an atomic force microscope cantilever is often needed for quantitative measurements. The calibration method of Sader et al. [Rev. Sci. Instrum. 70, 3967 (1999)] for a rectangular cantilever requires measurement of the resonant frequency and quality factor in fluid (typically air), and knowledge of its plan view dimensions. This intrinsically uses the hydrodynamic function for a cantilever of rectangular plan view geometry. Here, we present hydrodynamic functions for a series of irregular and non-rectangular atomic force microscope cantilevers that are commonly used in practice. Cantilever geometries of arrow shape, small aspect ratio rectangular, quasi-rectangular, irregular rectangular, non-ideal trapezoidal cross sections, and V-shape are all studied. This enables the spring constants of all these cantilevers to be accurately and routinely determined through measurement of their resonant frequency and quality factor in fluid (such as air). An approximate formulation of the hydrodynamic function for microcantilevers of arbitrary geometry is also proposed. Implementation of the method and its performance in the presence of uncertainties and non-idealities is discussed, together with conversion factors for the static and dynamic spring constants of these cantilevers. These results are expected to be of particular value to the design and application of micro- and nanomechanical systems in general.

  14. Characterizing the free and surface-coupled vibrations of heated-tip atomic force microscope cantilevers.

    Science.gov (United States)

    Killgore, Jason P; Tung, Ryan C; Hurley, Donna C

    2014-08-29

    Combining heated-tip atomic force microscopy (HT-AFM) with quantitative methods for determining surface mechanical properties, such as contact resonance force microscopy, creates an avenue for nanoscale thermomechanical property characterization. For nanomechanical methods that employ an atomic force microscope cantilever's vibrational modes, it is essential to understand how the vibrations of the U-shaped HT-AFM cantilever differ from those of a more traditional rectangular lever, for which analytical techniques are better developed. Here we show, with a combination of finite element analysis (FEA) and experiments, that the HT-AFM cantilever exhibits many more readily-excited vibrational modes over typical AFM frequencies compared to a rectangular cantilever. The arms of U-shaped HT-AFM cantilevers exhibit two distinct forms of flexural vibrations that differ depending on whether the two arms are vibrating in-phase or out-of-phase with one another. The in-phase vibrations are qualitatively similar to flexural vibrations in rectangular cantilevers and generally show larger sensitivity to surface stiffness changes than the out-of-phase vibrations. Vibration types can be identified from their frequency and by considering vibration amplitudes in the horizontal and vertical channels of the AFM at different laser spot positions on the cantilever. For identifying contact resonance vibrational modes, we also consider the sensitivity of the resonant frequencies to a change in applied force and hence to tip-sample contact stiffness. Finally, we assess how existing analytical models can be used to accurately predict contact stiffness from contact-resonance HT-AFM results. A simple two-parameter Euler-Bernoulli beam model provided good agreement with FEA for in-phase modes up to a contact stiffness 500 times the cantilever spring constant. By providing insight into cantilever vibrations and exploring the potential of current analysis techniques, our results lay the groundwork

  15. The atomic force microscope as a mechano–electrochemical pen

    Directory of Open Access Journals (Sweden)

    Christian Obermair

    2011-10-01

    Full Text Available We demonstrate a method that allows the controlled writing of metallic patterns on the nanometer scale using the tip of an atomic force microscope (AFM as a “mechano–electrochemical pen”. In contrast to previous experiments, no voltage is applied between the AFM tip and the sample surface. Instead, a passivated sample surface is activated locally due to lateral forces between the AFM tip and the sample surface. In this way, the area of tip–sample interaction is narrowly limited by the mechanical contact between tip and sample, and well-defined metallic patterns can be written reproducibly. Nanoscale structures and lines of copper were deposited, and the line widths ranged between 5 nm and 80 nm, depending on the deposition parameters. A procedure for the sequential writing of metallic nanostructures is introduced, based on the understanding of the passivation process. The mechanism of this mechano–electrochemical writing technique is investigated, and the processes of site-selective surface depassivation, deposition, dissolution and repassivation of electrochemically deposited nanoscale metallic islands are studied in detail.

  16. z calibration of the atomic force microscope by means of a pyramidal tip

    DEFF Research Database (Denmark)

    Jensen, Flemming

    1993-01-01

    A new method for imaging the probe tip of an atomic force microscope cantilever by the atomic force microscope itself (self-imaging) is presented. The self-imaging is accomplished by scanning the probe tip across a sharper tip on the surface. By using a pyramidal probe tip with a very well......-defined aspect ratio, this technique provides an excellent z-calibration standard for the atomic force microscope....

  17. Tip Effect of the Tapping Mode of Atomic Force Microscope in Viscous Fluid Environments.

    Science.gov (United States)

    Shih, Hua-Ju; Shih, Po-Jen

    2015-07-28

    Atomic force microscope with applicable types of operation in a liquid environment is widely used to scan the contours of biological specimens. The contact mode of operation allows a tip to touch a specimen directly but sometimes it damages the specimen; thus, a tapping mode of operation may replace the contact mode. The tapping mode triggers the cantilever of the microscope approximately at resonance frequencies, and so the tip periodically knocks the specimen. It is well known that the cantilever induces extra liquid pressure that leads to drift in the resonance frequency. Studies have noted that the heights of protein surfaces measured via the tapping mode of an atomic force microscope are ~25% smaller than those measured by other methods. This discrepancy may be attributable to the induced superficial hydrodynamic pressure, which is worth investigating. In this paper, we introduce a semi-analytical method to analyze the pressure distribution of various tip geometries. According to our analysis, the maximum hydrodynamic pressure on the specimen caused by a cone-shaped tip is ~0.5 Pa, which can, for example, pre-deform a cell by several nanometers in compression before the tip taps it. Moreover, the pressure calculated on the surface of the specimen is 20 times larger than the pressure without considering the tip effect; these results have not been motioned in other papers. Dominating factors, such as surface heights of protein surface, mechanical stiffness of protein increasing with loading velocity, and radius of tip affecting the local pressure of specimen, are also addressed in this study.

  18. Atomic force microscope-based single-molecule force spectroscopy of RNA unfolding.

    Science.gov (United States)

    Heus, Hans A; Puchner, Elias M; van Vugt-Jonker, Aafke J; Zimmermann, Julia L; Gaub, Hermann E

    2011-07-01

    Single-molecule force spectroscopy (SMFS) using the atomic force microscope (AFM) has emerged as an important tool for probing biomolecular interaction and exploring the forces, dynamics, and energy landscapes that underlie function and specificity of molecular interaction. These studies require attaching biomolecules on solid supports and AFM tips to measure unbinding forces between individual binding partners. Herein we describe efficient and robust protocols for probing RNA interaction by AFM and show their value on two well-known RNA regulators, the Rev-responsive element (RRE) from the HIV-1 genome and an adenine-sensing riboswitch. The results show the great potential of AFM-SMFS in the investigation of RNA molecular interactions, which will contribute to the development of bionanodevices sensing single RNA molecules. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Quantification of the lateral detachment force for bacterial cells using atomic force microscope and centrifugation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Tong, E-mail: zhangt@hkucc.hku.hk [Environmental Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong (China); Chao, Yuanqing; Shih, Kaimin; Li, Xiao-Yan; Fang, Herbert H.P. [Environmental Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong (China)

    2011-01-15

    To determine the lateral detachment force for individual bacterial cells, a quantitative method using the contact mode of an atomic force microscope (AFM) was developed in this study. Three key factors for the proposed method, i.e. scan size, scan rate and cantilever choice, were evaluated and optimized. The scan size of 40x40 {mu}m{sup 2} was optimal for capturing sufficient number of adhered cells in a microscopic field and provide adequate information for cell identification and detachment force measurement. The scan rate affected the measurement results significantly, and was optimized at 40 {mu}m/s considering both force measurement accuracy and experimental efficiency. The hardness of applied cantilevers also influenced force determination. The proposed protocol for cantilever selection is to use those with the lowest spring constant first and then step up to a harder cantilever until all cells are detached. The lateral detachment force of Escherichia coli cells on polished stainless steel and a glass-slide coated with poly-L-lysine were measured as 0.763{+-}0.167 and 0.639{+-}0.136 nN, respectively. The results showed that the established method had good repeatability and sensitivity to various bacteria/substrata combinations. The detachment force quantified by AFM (0.639{+-}0.136 nN) was comparable to that measured by the centrifugation method (1.12 nN). -- Research highlights: {yields} A quantitative method via AFM is developed to measure the lateral detachment force of an attached cell. {yields} The parameters of AFM operation for this method are optimized. {yields} The tests using E. coli on different substrata show that the method has good repeatability and sensitivity. {yields} The method could obtain reliable results that are comparable to those using the centrifugation approach.

  20. Uncertainty quantification in nanomechanical measurements using the atomic force microscope

    Science.gov (United States)

    Wagner, Ryan; Moon, Robert; Pratt, Jon; Shaw, Gordon; Raman, Arvind

    2011-11-01

    Quantifying uncertainty in measured properties of nanomaterials is a prerequisite for the manufacture of reliable nanoengineered materials and products. Yet, rigorous uncertainty quantification (UQ) is rarely applied for material property measurements with the atomic force microscope (AFM), a widely used instrument that can measure properties at nanometer scale resolution of both inorganic and biological surfaces and nanomaterials. We present a framework to ascribe uncertainty to local nanomechanical properties of any nanoparticle or surface measured with the AFM by taking into account the main uncertainty sources inherent in such measurements. We demonstrate the framework by quantifying uncertainty in AFM-based measurements of the transverse elastic modulus of cellulose nanocrystals (CNCs), an abundant, plant-derived nanomaterial whose mechanical properties are comparable to Kevlar fibers. For a single, isolated CNC the transverse elastic modulus was found to have a mean of 8.1 GPa and a 95% confidence interval of 2.7-20 GPa. A key result is that multiple replicates of force-distance curves do not sample the important sources of uncertainty, which are systematic in nature. The dominant source of uncertainty is the nondimensional photodiode sensitivity calibration rather than the cantilever stiffness or Z-piezo calibrations. The results underscore the great need for, and open a path towards, quantifying and minimizing uncertainty in AFM-based material property measurements of nanoparticles, nanostructured surfaces, thin films, polymers and biomaterials. This work is a partial contribution of the USDA Forest Service and NIST, agencies of the US government, and is not subject to copyright.

  1. A metrological large range atomic force microscope with improved performance.

    Science.gov (United States)

    Dai, Gaoliang; Wolff, Helmut; Pohlenz, Frank; Danzebrink, Hans-Ulrich

    2009-04-01

    A metrological large range atomic force microscope (Met. LR-AFM) has been set up and improved over the past years at Physikalisch-Technische Bundesanstalt (PTB). Being designed as a scanning sample type instrument, the sample is moved in three dimensions by a mechanical ball bearing stage in combination with a compact z-piezostage. Its topography is detected by a position-stationary AFM head. The sample displacement is measured by three embedded miniature homodyne interferometers in the x, y, and z directions. The AFM head is aligned in such a way that its cantilever tip is positioned on the sample surface at the intersection point of the three interferometer measurement beams for satisfying the Abbe measurement principle. In this paper, further improvements of the Met. LR-AFM are reported. A new AFM head using the beam deflection principle has been developed to reduce the influence of parasitic optical interference phenomena. Furthermore, an off-line Heydemann correction method has been applied to reduce the inherent interferometer nonlinearities to less than 0.3 nm (p-v). Versatile scanning functions, for example, radial scanning or local AFM measurement functions, have been implemented to optimize the measurement process. The measurement software is also improved and allows comfortable operations of the instrument via graphical user interface or script-based command sets. The improved Met. LR-AFM is capable of measuring, for instance, the step height, lateral pitch, line width, nanoroughness, and other geometrical parameters of nanostructures. Calibration results of a one-dimensional grating and a set of film thickness standards are demonstrated, showing the excellent metrological performance of the instrument.

  2. A scanning force microscope for simultaneous force and patch-clamp measurements on living cell tissues

    Science.gov (United States)

    Langer, M. G.; Öffner, W.; Wittmann, H.; Flösser, H.; Schaar, H.; Häberle, W.; Pralle, A.; Ruppersberg, J. P.; Hörber, J. K. H.

    1997-06-01

    For the investigation of mechanosensitive ion channels of living cells it is of great interest to apply very local forces in the piconewton range and to measure, simultaneously, ion currents down to 1 pA. Scanning force microscopy (SFM) is a suitable technique, that allows the application of such small forces with a lateral resolution in the range of 10 nm. We developed a novel type of experimental setup, because no existing SFM, home built or commercial, allows a simultaneous investigation of ion currents and mechanical properties of living cells. The construction consists of a SFM that is combined with an upright infrared differential interference contrast (DIC) video microscope and a conventional patch-clamp setup. Instead of the object, the force sensor is scanned to prevent relative movements between the patch pipette and the patched cell. The deflection of the SFM cantilever is detected with the so-called optical deflection method through the objective of the optical microscope. In opposite to common optical setups the laser beam was not focused on the force sensor. The presented optic creates a parallel laser beam between the objective and the SFM cantilever, which allows a vertical displacement of the sensor without any changes of the detector signal. For the three-dimensional positioning of the specimen chamber a two-axis translation stage including a vertical piezoelectric translation device was developed. The SFM tip is fixed on a combined lateral and vertical translation stage including a piezoelectric tube scanner for three-dimensional fine positioning. Thus the instrument enables an easy approach of the SFM tip to any optically identified cell structure. The head stage of the patch-clamp electronics and the patch pipette are directly fixed on the specimen stage. This prevents relative movements between patched cells and patch pipette during the approach to the SFM tip. The three-axis positioning of the patch pipette is done by a compact hydraulic

  3. Probed adhesion force of living lung cells with a tip-modified atomic force microscope.

    Science.gov (United States)

    Fu, Wei-En; Sivashanmugan, Kundan; Liao, Jiunn-Der; Lin, Ying-Yi; Cheng, Kai-Hung; Liu, Bernard Haochih; Yan, Jun-Jer; Yeh, Ming-Hong

    2016-12-19

    The mechanical properties of the extracellular matrix play an important role in bio-microenvironment activities. Herein, atomic force microscope (AFM) was used to measure the interaction between Au and Ag nanoparticle (NP) clusters on the surface of human fetal lung cells. Using (3-mercapto-propyl) triethoxysilane (MPTMS), NP clusters were grafted onto the apex of AFM tip, and then, the adhesion force between the tip and the cell was analyzed. The measured adhesion force increased from 92 pN for AFM tip to 332 pN for that modified with MPTMS. The increase is most probably contributed by the nonspecific interactions between the apex of the modified AFM tip and the surface of the cells. The adhesion forces between the surface of NPs clusters grafted AFM tip and that of lung cells were dramatically reduced as NPs clusters were replaced by MPTMS. For the former, as the Au NPs cluster was applied, the adhesion force reached to 122 pN, whereas it significantly augmented with the addition of the cluster's size and dimension on the AFM tip. For the case of Ag cluster grafted on AFM tip, its adhesion force with the surface of the cells significantly lowered and reduced to 56 pN. Presumably, the electrostatic or van der Waals force between the two surfaces results in the variation of measurements. It is also very likely that the cell-surface interactions are probably varied by the nature of the contact surfaces, like the force-distance of attraction. The result is significant for understanding the the nature of the interactions between the surface of NPs and the membrane of lung cells.

  4. Capillary force on a tilted cylinder: Atomic Force Microscope (AFM) measurements.

    Science.gov (United States)

    Kosgodagan Acharige, Sébastien; Laurent, Justine; Steinberger, Audrey

    2017-11-01

    The capillary force in situations where the liquid meniscus is asymmetric, such as the one around a tilted object, has been hitherto barely investigated even though these situations are very common in practice. In particular, the capillary force exerted on a tilted object may depend on the dipping angle i. We investigate experimentally the capillary force that applies on a tilted cylinder as a function of its dipping angle i, using a home-built tilting Atomic Force Microscope (AFM) with custom made probes. A micrometric-size rod is glued at the end of an AFM cantilever of known stiffness, whose deflection is measured when the cylindrical probe is dipped in and retracted from reference liquids. We show that a torque correction is necessary to understand the measured deflection. We give the explicit expression of this correction as a function of the probes' geometrical parameters, so that its magnitude can be readily evaluated. The results are compatible with a vertical capillary force varying as 1/cosi, in agreement with a recent theoretical prediction. Finally, we discuss the accuracy of the method for measuring the surface tension times the cosine of the contact angle of the liquid on the probe. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. An open source/real-time atomic force microscope architecture to perform customizable force spectroscopy experiments.

    Science.gov (United States)

    Materassi, Donatello; Baschieri, Paolo; Tiribilli, Bruno; Zuccheri, Giampaolo; Samorì, Bruno

    2009-08-01

    We describe the realization of an atomic force microscope architecture designed to perform customizable experiments in a flexible and automatic way. Novel technological contributions are given by the software implementation platform (RTAI-LINUX), which is free and open source, and from a functional point of view, by the implementation of hard real-time control algorithms. Some other technical solutions such as a new way to estimate the optical lever constant are described as well. The adoption of this architecture provides many degrees of freedom in the device behavior and, furthermore, allows one to obtain a flexible experimental instrument at a relatively low cost. In particular, we show how such a system has been employed to obtain measures in sophisticated single-molecule force spectroscopy experiments [Fernandez and Li, Science 303, 1674 (2004)]. Experimental results on proteins already studied using the same methodologies are provided in order to show the reliability of the measure system.

  6. Novel parallel plate condenser for single particle electrostatic force measurements in atomic force microscope

    KAUST Repository

    Kwek, Jin Wang

    2011-07-01

    A combination of small parallel plate condenser with Indium Tin Oxide (ITO) glass slides as electrodes and an atomic force microscope (AFM) is used to characterize the electrostatic behavior of single glass bead microparticles (105-150 μm) glued to the AFM cantilever. This novel setup allows measurements of the electrostatic forces acting on a particle in an applied electrical field to be performed in ambient air conditions. By varying the position of the microparticle between the electrodes and the strength of the applied electric field, the relative contributions of the particle net charge, induced and image charges were investigated. When the microparticle is positioned in the middle of the electrodes, the force acting on the microparticle was linear with the applied electric field and proportional to the microparticle net charge. At distances close to the bottom electrode, the force follows a parabolic relationship with the applied electric field reflecting the contributions of induced and image charges. The method can be used for the rapid evaluation of the charging and polarizability properties of the microparticle as well as an alternative to the conventional Faraday\\'s pail technique. © 2011 Elsevier B.V.

  7. Controlling chaos in dynamic-mode atomic force microscope

    OpenAIRE

    Yamasue, Kohei; Kobayashi, Kei; Yamada, Hirofumi; Matsushige, Kazumi; Hikihara, Takashi

    2009-01-01

    We successfully demonstrated the first experimental stabilization of irregular and non-periodic cantilever oscillation in the amplitude modulation atomic force microscopy using the time-delayed feedback control. A perturbation to cantilever excitation force stabilized an unstable periodic orbit associated with nonlinear cantilever dynamics. Instead of the typical piezoelectric excitation, the magnetic excitation was used for directly applying control force to the cantilever. The control force...

  8. A Cost-Effective Atomic Force Microscope for Undergraduate Control Laboratories

    Science.gov (United States)

    Jones, C. N.; Goncalves, J.

    2010-01-01

    This paper presents a simple, cost-effective and robust atomic force microscope (AFM), which has been purposely designed and built for use as a teaching aid in undergraduate controls labs. The guiding design principle is to have all components be open and visible to the students, so the inner functioning of the microscope has been made clear to…

  9. Microscopic derivation of macroscopic Van der Waals forces

    NARCIS (Netherlands)

    Renne, M.J.; Nijboer, B.R.A.

    1967-01-01

    For a general system of isotropic harmonic oscillators with non-retarded dipole interaction a formula for the interatomic forces is derived. It is used to give an atomistic derivation of macroscopic Van der Waals forces in terms of the dielectric constant.

  10. Simultaneous topography imaging and broadband nanomechanical mapping on atomic force microscope

    Science.gov (United States)

    Li, Tianwei; Zou, Qingze

    2017-12-01

    In this paper, an approach is proposed to achieve simultaneous imaging and broadband nanomechanical mapping of soft materials in air by using an atomic force microscope. Simultaneous imaging and nanomechanical mapping are needed, for example, to correlate the morphological and mechanical evolutions of the sample during dynamic phenomena such as the cell endocytosis process. Current techniques for nanomechanical mapping, however, are only capable of capturing static elasticity of the material, or the material viscoelasticity in a narrow frequency band around the resonant frequency(ies) of the cantilever used, not competent for broadband nanomechanical mapping, nor acquiring topography image of the sample simultaneously. These limitations are addressed in this work by enabling the augmentation of an excitation force stimuli of rich frequency spectrum for nanomechanical mapping in the imaging process. Kalman-filtering technique is exploited to decouple and split the mixed signals for imaging and mapping, respectively. Then the sample indentation generated is quantified online via a system-inversion method, and the effects of the indentation generated and the topography tracking error on the topography quantification are taken into account. Moreover, a data-driven feedforward-feedback control is utilized to track the sample topography. The proposed approach is illustrated through experimental implementation on a polydimethylsiloxane sample with a pre-fabricated pattern.

  11. Two-probe atomic-force microscope manipulator and its applications.

    Science.gov (United States)

    Zhukov, A A; Stolyarov, V S; Kononenko, O V

    2017-06-01

    We report on a manipulator based on a two-probe atomic force microscope (AFM) with an individual feedback system for each probe. This manipulator works under an upright optical microscope with 3 mm focal distance. The design of the microscope helps us tomanipulate nanowires using the microscope probes as a two-prong fork. The AFM feedback is realized based on the dynamic full-time contact mode. The applications of the manipulator and advantages of its two-probe design are presented.

  12. Design of a self-aligned, wide temperature range (300 mK-300 K) atomic force microscope/magnetic force microscope with 10 nm magnetic force microscope resolution

    Energy Technology Data Exchange (ETDEWEB)

    Karcı, Özgür [NanoMagnetics Instruments Ltd., Hacettepe - İvedik OSB Teknokent, 1368. Cad., No: 61/33, 06370, Yenimahalle, Ankara (Turkey); Department of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara (Turkey); Dede, Münir [NanoMagnetics Instruments Ltd., Hacettepe - İvedik OSB Teknokent, 1368. Cad., No: 61/33, 06370, Yenimahalle, Ankara (Turkey); Oral, Ahmet, E-mail: orahmet@metu.edu.tr [Department of Physics, Middle East Technical University, 06800 Ankara (Turkey)

    2014-10-01

    We describe the design of a wide temperature range (300 mK-300 K) atomic force microscope/magnetic force microscope with a self-aligned fibre-cantilever mechanism. An alignment chip with alignment groves and a special mechanical design are used to eliminate tedious and time consuming fibre-cantilever alignment procedure for the entire temperature range. A low noise, Michelson fibre interferometer was integrated into the system for measuring deflection of the cantilever. The spectral noise density of the system was measured to be ~12 fm/√Hz at 4.2 K at 3 mW incident optical power. Abrikosov vortices in BSCCO(2212) single crystal sample and a high density hard disk sample were imaged at 10 nm resolution to demonstrate the performance of the system.

  13. Fabrication of Josephson junctions by using an atomic force microscope

    CERN Document Server

    Song, I S; Kim, D H; Park, G S

    2000-01-01

    Josephson junctions have been fabricated by using an atomic foce microscope (AFM) for surface modification. YBCO films were fabricated on MgO substrates by using pulsed laser deposition. Surface modification of YBCO strips in the field of conductive AFM tips results in controlled and systematic growth of protrusions across the entire strip. Increasing the negative bias voltage to the AFM tip linearly increases the size of the modified structures. The offset superconducting transition temperature and the critical current values systematically shift to lower temperature and current values with increasing degree of AFM modification.

  14. Optical microscope combined with the nanopipette-based quartz tuning fork-atomic force microscope for nanolithography

    Science.gov (United States)

    An, Sangmin; Stambaugh, Corey; Kwon, Soyoung; Lee, Kunyoung; Kim, Bongsu; Kim, Qwhan; Jhe, Wonho

    2013-09-01

    We demonstrated the optical microscope (OM) combined with nanopipette-based quartz tuning fork - atomic force microscope (QTF-AFM) for nanolithography. The nanoparticle (Au, 5 nm), nanowire, PDMS solutions are ejected onto the substrate through the nano/microaperture of the pulled pipette, and the nano/microscale objects were in-situ formed on the surface with the proposed patterning system, while the position is defined by monitoring the phenomena on the substrate with a home-made OM. After forming of capillary condensation between apex of the pipette tip and the surface, the electric field is applied to extract out the inside liquid to the substrate and the nano/microscale objects are fabricated. The nanoscale patterning size can be controlled by the aperture diameters of the pulled pipette.

  15. Atomic force microscope infrared spectroscopy of griseofulvin nanocrystals.

    Science.gov (United States)

    Harrison, Aaron J; Bilgili, Ecevit A; Beaudoin, Stephen P; Taylor, Lynne S

    2013-12-03

    The goal of this work was to evaluate the ability of photothermal-induced resonance (PTIR) to measure the local infrared absorption spectra of crystalline organic drug nanoparticles embedded within solid matrices. Herein, the first reports of the chemical characterization of sub-100 nm organic crystals are described; infrared spectra of 90 nm griseofulvin particles were obtained, confirming the chemical resolution of PTIR beyond the diffraction limit. Additionally, particle size distributions via dynamic light scattering and PTIR image analysis were found to be similar, suggesting that the PTIR measurements are not significantly affected by inhomogeneous infrared absorptivity of this system. Thus as medical applications increasingly emphasize localized drug delivery via micro/nanoengineered structures, PTIR can be used to unambiguously chemically characterize drug formulations at these length scales.

  16. Measuring the interaction forces between protein inclusion bodies and an air bubble using an atomic force microscope.

    Science.gov (United States)

    Wangsa-Wirawan, N D; Ikai, A; O'Neill, B K; Middelberg, A P

    2001-01-01

    Interaction forces between protein inclusion bodies and an air bubble have been quantified using an atomic force microscope (AFM). The inclusion bodies were attached to the AFM tip by covalent bonds. Interaction forces measured in various buffer concentrations varied from 9.7 nN to 25.3 nN (+/- 4-11%) depending on pH. Hydrophobic forces provide a stronger contribution to overall interaction force than electrostatic double layer forces. It also appears that the ionic strength affects the interaction force in a complex way that cannot be directly predicted by DLVO theory. The effects of pH are significantly stronger for the inclusion body compared to the air bubble. This study provides fundamental information that will subsequently facilitate the rational design of flotation recovery system for inclusion bodies. It has also demonstrated the potential of AFM to facilitate the design of such processes from a practical viewpoint.

  17. Combined laser and atomic force microscope lithography on aluminum: Mask fabrication for nanoelectromechanical systems

    DEFF Research Database (Denmark)

    Berini, Abadal Gabriel; Boisen, Anja; Davis, Zachary James

    1999-01-01

    A direct-write laser system and an atomic force microscope (AFM) are combined to modify thin layers of aluminum on an oxidized silicon substrate, in order to fabricate conducting and robust etch masks with submicron features. These masks are very well suited for the production of nanoelectromecha......A direct-write laser system and an atomic force microscope (AFM) are combined to modify thin layers of aluminum on an oxidized silicon substrate, in order to fabricate conducting and robust etch masks with submicron features. These masks are very well suited for the production...

  18. Midinfrared absorption measured at a lambda/400 resolution with an atomic force microscope.

    Science.gov (United States)

    Houel, Julien; Homeyer, Estelle; Sauvage, Sébastien; Boucaud, Philippe; Dazzi, Alexandre; Prazeres, Rui; Ortéga, Jean-Michel

    2009-06-22

    Midinfrared absorption can be locally measured using a detection combining an atomic force microscope and a pulsed excitation. This is illustrated for the midinfrared bulk GaAs phonon absorption and for the midinfrared absorption of thin SiO(2) microdisks. We show that the signal given by the cantilever oscillation amplitude of the atomic force microscope follows the spectral dependence of the bulk material absorption. The absorption spatial resolution achieved with microdisks is around 50 nanometer for an optical excitation around 22 micrometer wavelength.

  19. Pressure solution observed with an atomic force microscope

    Science.gov (United States)

    Colombani, J.; Pachon-Rodriguez, E. A.; Piednoir, A.

    2012-04-01

    Dissolution of minerals is involved in many geological and environmental processes, often with large human consequences. One can cite the durability of mineral materials, the management of nuclear wastes, the sequestration of atmospheric CO2 or the pollution of drinking water. Progresses have been made during the last decade in our understanding of the basic mechanisms of dissolution, particularly concerning the nature of the reactive surface, the role of etch pits, the influence of the mineral history, the mineral replacement processes, ... One of the remaining problems is the influence of an elastic stress on the nature and rate of dissolution. For instance a large discrepancy still exists between experimental results and modelling of pressure solution creep, a plastic strain mechanism of minerals based on the dissolution enhancement by an external stress. We present here an experimental evidence of the influence of a local stress on a molecular elementary mechanism of dissolution. This was performed by atomic force microscopy observation of the migration of a molecular step on the surface of a single crystal of gypsum during dissolution, where the AFM tip is used alternatively to apply a stress and probe the surface. The kinetics of this atomic mechanism is seen to obey the same law of pressure solution as the corresponding macroscopic phenomenon.

  20. High-throughput atomic force microscopes operating in parallel

    Science.gov (United States)

    Sadeghian, Hamed; Herfst, Rodolf; Dekker, Bert; Winters, Jasper; Bijnagte, Tom; Rijnbeek, Ramon

    2017-03-01

    Atomic force microscopy (AFM) is an essential nanoinstrument technique for several applications such as cell biology and nanoelectronics metrology and inspection. The need for statistically significant sample sizes means that data collection can be an extremely lengthy process in AFM. The use of a single AFM instrument is known for its very low speed and not being suitable for scanning large areas, resulting in a very-low-throughput measurement. We address this challenge by parallelizing AFM instruments. The parallelization is achieved by miniaturizing the AFM instrument and operating many of them simultaneously. This instrument has the advantages that each miniaturized AFM can be operated independently and that the advances in the field of AFM, both in terms of speed and imaging modalities, can be implemented more easily. Moreover, a parallel AFM instrument also allows one to measure several physical parameters simultaneously; while one instrument measures nano-scale topography, another instrument can measure mechanical, electrical, or thermal properties, making it a lab-on-an-instrument. In this paper, a proof of principle of such a parallel AFM instrument has been demonstrated by analyzing the topography of large samples such as semiconductor wafers. This nanoinstrument provides new research opportunities in the nanometrology of wafers and nanolithography masks by enabling real die-to-die and wafer-level measurements and in cell biology by measuring the nano-scale properties of a large number of cells.

  1. Microscopic coupled-channel study of molecular resonances in {sup 12}Be

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Makoto; Kato, Kiyoshi [Hokkaido Univ., Graduate School of Science, Division of Physics, Sapporo (Japan); Sakuragi, Yukinori [Osaka City Univ. (Japan). Dept. of Physics; Hiyama, Emiko [High Energy Accelerator Research Organization, Institute for Particle and Nuclear Studies, Tsukuba, Ibaraki (Japan); Kamimura, Masayasu [Kyushu Univ., Fukuoka (Japan). Dept. of Physics

    2001-09-01

    Molecular resonances recently observed in the {sup 12}Be{yields}{sup 6}He + {sup 6}He breakup-reaction experiment are studied by the microscopic coupled-channel (CC) calculation of the {sup 6}He +{sup 6}He system, in which excitations of interacting {sup 6}He nuclei are taken into account by the microscopic internal wave functions of {sup 6}He and realistic nucleon-nucleon interactions. The CC calculation predicts several molecular-rotational bands in the energy range of the observed resonances and the energies and spins of the calculated resonances well agree with the experimental data. The results of the CC calculation strongly suggest that the observed resonance states with spins larger than 6h may be interpreted in terms of 'the excited-weak-coupling states', in which one or both interacting {sup 6}He nuclei are excited and they are weakly coupled to each other. The effect of the coupling to the {sup 4}He + {sup 8}He channel, in which the resonance states were also observed in the breakup reaction of {sup 12}Be, is also discussed. (author)

  2. High-sensitivity imaging with lateral resonance mode atomic force microscopy.

    Science.gov (United States)

    Ding, Ren-Feng; Yang, Chih-Wen; Huang, Kuang-Yuh; Hwang, Ing-Shouh

    2016-11-03

    In the operation of a dynamic mode atomic force microscope, a micro-fabricated rectangular cantilever is typically oscillated at or near its mechanical resonance frequency. Lateral bending resonances of cantilevers are rarely used because the resonances are not expected to be detected by the beam-deflection method. In this work, we found that micro-cantilevers with a large tip produced an out-of-plane displacement in lateral resonance (LR), which could be detected with the beam-deflection method. Finite-element analysis indicated that the presence of a large tip is the major source of the out-of-plane coupling for the LR. We also imaged a heterogeneous sample by operating a cantilever in LR, torsional resonance, and tapping modes. LR mode yielded a small deformation and noise level in the height maps as well as a high contrast and small noise level in the phase maps. LR mode also had a resonance frequency that was orders of magnitude higher than that of tapping mode. Operation with LR mode may have the benefits of high-speed scanning, high-sensitivity imaging, and mapping of in-plane mechanical properties of the sample surface. In general, LR mode may become a powerful new atomic force microscopy technique for characterizing sample materials.

  3. Atomic force microscopic imaging of Acanthamoeba castellanii and Balamuthia mandrillaris trophozoites and cysts.

    Science.gov (United States)

    Aqeel, Yousuf; Siddiqui, Ruqaiyyah; Ateeq, Muhammad; Raza Shah, Muhammad; Kulsoom, Huma; Khan, Naveed Ahmed

    2015-01-01

    Light microscopy and electron microscopy have been successfully used in the study of microbes, as well as free-living protists. Unlike light microscopy, which enables us to observe living organisms or the electron microscope which provides a two-dimensional image, atomic force microscopy provides a three-dimensional surface profile. Here, we observed two free-living amoebae, Acanthamoeba castellanii and Balamuthia mandrillaris under the phase contrast inverted microscope, transmission electron microscope and atomic force microscope. Although light microscopy was of lower magnification, it revealed functional biology of live amoebae such as motility and osmoregulation using contractile vacuoles of the trophozoite stage, but it is of limited value in defining the cyst stage. In contrast, transmission electron microscopy showed significantly greater magnification and resolution to reveal the ultra-structural features of trophozoites and cysts including intracellular organelles and cyst wall characteristics but it only produced a snapshot in time of a dead amoeba cell. Atomic force microscopy produced three-dimensional images providing detailed topographic description of shape and surface, phase imaging measuring boundary stiffness, and amplitude measurements including width, height and length of A. castellanii and B. mandrillaris trophozoites and cysts. These results demonstrate the importance of the application of various microscopic methods in the biological and structural characterization of the whole cell, ultra-structural features, as well as surface components and cytoskeleton of protist pathogens. © 2014 The Author(s) Journal of Eukaryotic Microbiology © 2014 International Society of Protistologists.

  4. Direct proton decay and microscopic structure of the spin-dipole resonance in Bi-208

    NARCIS (Netherlands)

    Akimune, H; Daito, [No Value; Fujita, Y; Fujiwara, M; Harakeh, MN; Janecke, J; Yosoi, M

    The microscopic structure of the spin-dipole resonance (SDR) at E-x = 21.1 MeV in Bi-208 has been investigated in the Pb-208(He-3,t)Bi-208 reaction at E(He-3) = 450 MeV and very forward scattering angles. Protons emitted due to the decay of the SDR were measured in solid-state detectors in

  5. Position-resolved Surface Characterization and Nanofabrication Using an Optical Microscope Combined with a Nanopipette/Quartz Tuning Fork Atomic Force Microscope

    National Research Council Canada - National Science Library

    Sangmin An Baekman Sung Haneol Noh Corey Stambaugh Soyoung Kwon Kunyoung Lee Bongsu Kim Qhwan Kim Wonho Jhe

    2014-01-01

    ...) combined with a nanopipette-based quartz tuning fork atomic force microscope(nanopipette/QTF-AFM) system. This system is used to accurately determine substrate position and nanoscale phenomena under ambient conditions...

  6. Position-resolved Surface Characterization and Nanofabrication Using an Optical Microscope Combined with a Nanopipette/Quartz Tuning Fork Atomic Force Microscope

    National Research Council Canada - National Science Library

    An, Sangmin; Sung, Baekman; Noh, Haneol; Stambaugh, Corey; Kwon, Soyoung; Lee, Kunyoung; Kim, Bongsu; Kim, Qhwan; Jhe, Wonho

    2014-01-01

    ...) combined with a nanopipette-based quartz tuning fork atomic force microscope (nanopipette/QTF-AFM) system. This system is used to accurately determine substrate position and nanoscale phenomena under ambient conditions...

  7. Micromachined fountain pen as a tool for atomic force microscope-based nanoelectrochemical metal deposition

    NARCIS (Netherlands)

    Deladi, S.; Tas, Niels Roelof; Berenschot, Johan W.; de Boer, Meint J.; Krijnen, Gijsbertus J.M.; Elwenspoek, Michael Curt; de Boer, J.H.

    2005-01-01

    We present a device that enables nanoelectrochemical deposition using atomic force microscope. The micromachined fountain pen is a probe that consists of a fluidic reservoir, fluidic channels encapsulated in cantilevers and a pyramidal probe tip by which the fluid transfer to the sample surface

  8. Nano Goes to School: A Teaching Model of the Atomic Force Microscope

    Science.gov (United States)

    Planinsic, Gorazd; Kovac, Janez

    2008-01-01

    The paper describes a teaching model of the atomic force microscope (AFM), which proved to be successful in the role of an introduction to nanoscience in high school. The model can demonstrate the two modes of operation of the AFM (contact mode and oscillating mode) as well as some basic principles that limit the resolution of the method. It can…

  9. Atomic force microscope with combined FTIR-Raman spectroscopy having a micro thermal analyzer

    Science.gov (United States)

    Fink, Samuel D [Aiken, SC; Fondeur, Fernando F [North Augusta, SC

    2011-10-18

    An atomic force microscope is provided that includes a micro thermal analyzer with a tip. The micro thermal analyzer is configured for obtaining topographical data from a sample. A raman spectrometer is included and is configured for use in obtaining chemical data from the sample.

  10. An atomic force microscope operating at hypergravity for in situ measurement of cellular mechano-response

    NARCIS (Netherlands)

    van Loon, J.J.W.A.; van Laar, M.C.; Korterik, J.P.; Segerink, F.B.; Wubbels, R.J.; de Jong, H.A.A.; van Hulst, N.F.

    2009-01-01

    We present a novel atomic force microscope (AFM) system, operational in liquid at variable gravity, dedicated to image cell shape changes of cells in vitro under hypergravity conditions. The hypergravity AFM is realized by mounting a stand-alone AFM into a large-diameter centrifuge. The balance

  11. A Computer-Controlled Classroom Model of an Atomic Force Microscope

    Science.gov (United States)

    Engstrom, Tyler A.; Johnson, Matthew M.; Eklund, Peter C.; Russin, Timothy J.

    2015-01-01

    The concept of "seeing by feeling" as a way to circumvent limitations on sight is universal on the macroscopic scale--reading Braille, feeling one's way around a dark room, etc. The development of the atomic force microscope (AFM) in 1986 extended this concept to imaging in the nanoscale. While there are classroom demonstrations that use…

  12. The shear-force/ultrasonic near-field microscope: a nanometrology tool for surface science and technology

    Science.gov (United States)

    La Rosa, A.; Li, N.; Asante, K.

    2005-11-01

    This paper describes recent results obtained with the Ultrasonic/Shear-Force Microscope (SUNM), an analytical tool suitable for investigating the quite different dynamic displayed by fluid-like films when subjected to mesoscopic confinement and while in intimate contact with two sliding solid boundaries. The SUNM uses two sensory modules to concurrently but independently monitor the effects that fluid-mediated interactions exert on two sliding bodies: the microscope's sharp probe (attached to a piezoelectric sensor) and the analyzed sample (attached to an ultrasonic transducer). This dual capability allows correlating the fluid-like film's viscoelastic properties with changes in the probe's resonance frequency and the generation of sound. A detailed monitoring of sliding friction by ultrasonic means and with nanometer resolution is unprecedented, which opens potential uses of the versatile microscope as a surface and subsurface material characterization tool. As a surface metrology tool, the SUNM presents a potential impact in diverse areas ranging from fundamental studies of nanotribology, confinement-driven solid to liquid phase transformation of polymer films, characterization of industrial lubricants, and the study of elastic properties of bio-membranes. As a sub-surface metrology tool, the SUNM can be used in the investigation of the elastic properties of low- and high-k dielectric materials, piezoelectric and ferroelectric films, as well as quality control in the construction of micro- and nano-fluidics devices.

  13. Phase Stochastic Resonance in a Forced Nanoelectromechanical Membrane.

    Science.gov (United States)

    Chowdhury, Avishek; Barbay, Sylvain; Clerc, Marcel G; Robert-Philip, Isabelle; Braive, Rémy

    2017-12-08

    Stochastic resonance is a general phenomenon usually observed in one-dimensional, amplitude modulated, bistable systems. We show experimentally the emergence of phase stochastic resonance in the bidimensional response of a forced nanoelectromechanical membrane by evidencing the enhancement of a weak phase modulated signal thanks to the addition of phase noise. Based on a general forced Duffing oscillator model, we demonstrate experimentally and theoretically that phase noise acts multiplicatively, inducing important physical consequences. These results may open interesting prospects for phase noise metrology or coherent signal transmission applications in nanomechanical oscillators. Moreover, our approach, due to its general character, may apply to various systems.

  14. Microscopic Theory for the Role of Attractive Forces in the Dynamics of Supercooled Liquids

    Science.gov (United States)

    Dell, Zachary E.; Schweizer, Kenneth S.

    2015-11-01

    We formulate a microscopic, no adjustable parameter, theory of activated relaxation in supercooled liquids directly in terms of the repulsive and attractive forces within the framework of pair correlations. Under isochoric conditions, attractive forces can nonperturbatively modify slow dynamics, but at high enough density their influence vanishes. Under isobaric conditions, attractive forces play a minor role. High temperature apparent Arrhenius behavior and density-temperature scaling are predicted. Our results are consistent with recent isochoric simulations and isobaric experiments on a deeply supercooled molecular liquid. The approach can be generalized to treat colloidal gelation and glass melting, and other soft matter slow dynamics problems.

  15. Minimizing pulling geometry errors in atomic force microscope single molecule force spectroscopy.

    Science.gov (United States)

    Rivera, Monica; Lee, Whasil; Ke, Changhong; Marszalek, Piotr E; Cole, Daniel G; Clark, Robert L

    2008-10-01

    In atomic force microscopy-based single molecule force spectroscopy (AFM-SMFS), it is assumed that the pulling angle is negligible and that the force applied to the molecule is equivalent to the force measured by the instrument. Recent studies, however, have indicated that the pulling geometry errors can drastically alter the measured force-extension relationship of molecules. Here we describe a software-based alignment method that repositions the cantilever such that it is located directly above the molecule's substrate attachment site. By aligning the applied force with the measurement axis, the molecule is no longer undergoing combined loading, and the full force can be measured by the cantilever. Simulations and experimental results verify the ability of the alignment program to minimize pulling geometry errors in AFM-SMFS studies.

  16. Geometric derivation of the microscopic stress: A covariant central force decomposition

    Science.gov (United States)

    Torres-Sánchez, Alejandro; Vanegas, Juan M.; Arroyo, Marino

    2016-08-01

    We revisit the derivation of the microscopic stress, linking the statistical mechanics of particle systems and continuum mechanics. The starting point in our geometric derivation is the Doyle-Ericksen formula, which states that the Cauchy stress tensor is the derivative of the free-energy with respect to the ambient metric tensor and which follows from a covariance argument. Thus, our approach to define the microscopic stress tensor does not rely on the statement of balance of linear momentum as in the classical Irving-Kirkwood-Noll approach. Nevertheless, the resulting stress tensor satisfies balance of linear and angular momentum. Furthermore, our approach removes the ambiguity in the definition of the microscopic stress in the presence of multibody interactions by naturally suggesting a canonical and physically motivated force decomposition into pairwise terms, a key ingredient in this theory. As a result, our approach provides objective expressions to compute a microscopic stress for a system in equilibrium and for force-fields expanded into multibody interactions of arbitrarily high order. We illustrate the proposed methodology with molecular dynamics simulations of a fibrous protein using a force-field involving up to 5-body interactions.

  17. Verification of cell viability at progressively higher scanning forces using a hybrid atomic force and fluorescence microscope.

    Science.gov (United States)

    Barnes, C A; O'Hagan, B M G; Howard, C V; McKerr, G

    2007-11-01

    The prudent use of the atomic force microscope as a supra-vital live cell imaging tool requires that cell viability must be determined before and after scanning. Complementary optical techniques in conjunction with the fluorescent dyes rhodamine-123 and ethidium homodimer have been used within this study to determine cell viability after increasing loads are applied in contact mode. Guideline force ranges for five commonly cultured cell lines, human squamous carcinoma (A431), fibroblast, HeLa, Potorous tridactylis (PtK2) and rat intestinal epithelial (RIE) cells are given.

  18. Effect of multiplicative noise on least-squares parameter estimation with applications to the atomic force microscope

    Science.gov (United States)

    Sader, John E.; Hughes, Barry D.; Sanelli, Julian A.; Bieske, Evan J.

    2012-05-01

    Measurement of the power spectral density of (stochastic) Brownian fluctuations of micro- and nano-devices is used frequently to gain insight into their mechanistic properties. Noise is always present in these measurements and can directly influence any parameter estimation obtained through a least-squares analysis. Importantly, measurements of the spectral density of stationary random signals, such as Brownian motion, inherently contain multiplicative noise. In this article, we theoretically analyze the impact of multiplicative noise on fit parameters extracted using a least-squares analysis. A general analysis is presented that is valid for any fit function with any number of fit parameters. This yields closed-form expressions for the expected value and variance in the fit parameters and provides a rigorous theoretical framework for a priori determination of the effect of measurement uncertainty. The theory is demonstrated and validated through Monte Carlo simulation of synthetic data and by comparison to power spectral density measurements of the Brownian fluctuations of an atomic force microscope cantilever - analytical formulas for the uncertainty in the fitted resonant frequency and quality factor are presented. The results of this study demonstrate that precise measurements of fit parameters in the presence of noise are inherently problematic - individual measurements of the power spectral density are capable of yielding fit parameters that are many standard deviations away from the mean, with finite probability. This is of direct relevance to a host of applications in measurement science, including those connected with the atomic force microscope.

  19. Ultrastable combined atomic force and total internal reflection fluorescence microscope [corrected].

    Science.gov (United States)

    Gumpp, H; Stahl, S W; Strackharn, M; Puchner, E M; Gaub, H E

    2009-06-01

    Combining atomic force microscope (AFM) with other microscopy techniques has expanded the range of potential applications for single molecule investigations dramatically. Particularly hybrid instruments with total internal reflection fluorescence (TIRF) excitation have opened new routes in life sciences. Here we present a novel design for such a hybrid microscope, which overcomes the limitations of conventional combinations caused by their limited mechanical stability. A thorough analysis of the noise spectra and a comparison of the different designs and the different operation modes are given. With this instrument we demonstrate single molecule manipulation by AFM and simultaneous TIRF imaging.

  20. Experimental elucidation: microscopic mechanism of resonant X-ray scattering in manganite films

    CERN Document Server

    Ohsumi, H; Kiyama, T

    2003-01-01

    Resonant X-ray scattering experiments have been performed on perovskite manganite La sub 0 sub . sub 5 Sr sub 0 sub . sub 5 MnO sub 3 thin films, which are grown on three distinct perovskite with a coherent epitaxial strain and have a forced ferro-type orbital ordering of Mn 3d orbitals. Using an interference technique, we have successfully observed the resonant X-ray scattering signal from the system having the ferro-type orbital ordering and also revealed the energy scheme of Mn 4p bands. For the forced ferro-type orbital ordering system, the present results evidence that the resonant X-ray scattering signal originates from the band structure effect due to the Jahn-Teller distortion of a MnO sub 6 octahedron, and not from the Coulomb interaction between 3d and 4p electrons. (author)

  1. Update on the OMERACT Magnetic Resonance Imaging Task Force

    DEFF Research Database (Denmark)

    Conaghan, Philip G; McQueen, Fiona M; Bird, Paul

    2014-01-01

    Magnetic resonance imaging (MRI) provides an important biomarker across a range of rheumatological diseases. At the Outcome Measures in Rheumatology (OMERACT) 11 meeting, the MRI task force continued its work of developing and improving the use of MRI outcomes for use in clinical trials...

  2. Magnetic resonance force microscopy using ferromagnetic resonance of a magnetic tip excited by microwave transmission via a coaxial resonator

    Science.gov (United States)

    Kinoshita, Yukinori; Li, Yan Jun; Yoshimura, Satoru; Saito, Hitoshi; Sugawara, Yasuhiro

    2017-12-01

    The present work proposes magnetic resonance force microscopy (MRFM) based on ferromagnetic resonance (FMR) modulation of a magnetic tip using microwave transmission via a coaxial resonator instead of using conventional microwave irradiation by an external antenna. In this MRFM, the coaxial resonator is electrically connected to the magnetic cantilever tip, which enables simple implementation of FMR excitation of a magnetic tip in conventional magnetic force microscopy. The FMR frequency of the tip can be easily extracted from the reflection spectrum of a transmission line connected to the magnetic tip. The excitation of tip FMR is confirmed from the microwave frequency dependence of the mechanical response of the tip oscillation. This MRFM is effective for extracting the magnetic interaction force near a sample surface without perturbation of its magnetic state. Nanometer-scale imaging of magnetic domain structures on a demagnetized thin-film permanent magnet is successfully demonstrated.

  3. Resonant dark forces and small-scale structure.

    Science.gov (United States)

    Tulin, Sean; Yu, Hai-Bo; Zurek, Kathryn M

    2013-03-15

    A dark force can impact the cosmological history of dark matter (DM), both explaining observed cores in dwarf galaxies and setting the DM relic density through annihilation to dark force bosons. For GeV-TeV DM mass, DM self-scattering in dwarf galaxy halos exhibits quantum mechanical resonances, analogous to a Sommerfeld enhancement for annihilation. We show that a simple model of DM with a dark force can accommodate all astrophysical bounds on self-interactions in halos and explain the observed relic density, through a single coupling constant.

  4. Morphology-Dependent Resonances of Spherical Droplets with Numerous Microscopic Inclusions

    Science.gov (United States)

    Mishchenko, Michael I.; Liu, Li; Mackowski, Daniel W.

    2014-01-01

    We use the recently extended superposition T-matrix method to study the behavior of a sharp Lorenz-Mie resonance upon filling a spherical micrometer-sized droplet with tens and hundreds of randomly positioned microscopic inclusions. We show that as the number of inclusions increases, the extinction cross-section peak and the sharp asymmetry-parameter minimum become suppressed, widen, and move toward smaller droplet size parameters, while ratios of diagonal elements of the scattering matrix exhibit sharp angular features indicative of a distinctly nonspherical particle. Our results highlight the limitedness of the concept of an effective refractive index of an inhomogeneous spherical particle.

  5. Development of a shear force scanning near-field fluorescence microscope for biological applications.

    Science.gov (United States)

    Shang, G Y; Qiao, W H; Lei, F H; Angiboust, J-F; Troyon, M; Manfait, M

    2005-11-01

    In this paper, a shear force scanning near-field fluorescence microscope combined with a confocal laser microspectrofluorometer is described. The shear force detection is realized based on a bimorph cantilever, which provides a very sensitive, reliable, and easy to use method to control the probe-sample distance during scanning. With the system, high-quality shear force imaging of various samples has been carried out. Furthermore, simultaneous shear force and near-field fluorescence imaging of biological cells has also been realized. As an example, we especially present the result on the distribution of P-glycoprotein in the plasma membrane of human small cell lung cancer cells, suggesting that the system would be a promising tool for biological applications.

  6. Probing the interaction between air bubble and sphalerite mineral surface using atomic force microscope.

    Science.gov (United States)

    Xie, Lei; Shi, Chen; Wang, Jingyi; Huang, Jun; Lu, Qiuyi; Liu, Qingxia; Zeng, Hongbo

    2015-03-03

    The interaction between air bubbles and solid surfaces plays important roles in many engineering processes, such as mineral froth flotation. In this work, an atomic force microscope (AFM) bubble probe technique was employed, for the first time, to directly measure the interaction forces between an air bubble and sphalerite mineral surfaces of different hydrophobicity (i.e., sphalerite before/after conditioning treatment) under various hydrodynamic conditions. The direct force measurements demonstrate the critical role of the hydrodynamic force and surface forces in bubble-mineral interaction and attachment, which agree well with the theoretical calculations based on Reynolds lubrication theory and augmented Young-Laplace equation by including the effect of disjoining pressure. The hydrophobic disjoining pressure was found to be stronger for the bubble-water-conditioned sphalerite interaction with a larger hydrophobic decay length, which enables the bubble attachment on conditioned sphalerite at relatively higher bubble approaching velocities than that of unconditioned sphalerite. Increasing the salt concentration (i.e., NaCl, CaCl2) leads to weakened electrical double layer force and thereby facilitates the bubble-mineral attachment, which follows the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory by including the effects of hydrophobic interaction. The results provide insights into the basic understanding of the interaction mechanism between bubbles and minerals at nanoscale in froth flotation processes, and the methodology on probing the interaction forces of air bubble and sphalerite surfaces in this work can be extended to many other mineral and particle systems.

  7. Nanostethoscopy: A new mode of operation of the atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Keaton, A.; Holzrichter, J.F.; Balhorn, R.; Siekaus, W.J.

    1994-02-01

    The authors introduce a new mode of operation of the atomic force microscope (AFM). This detection scheme, a {open_quotes}Nano-Stethoscope{close_quotes}. Involves using the atomic force microscope in a novel acoustic mode not generally recognized. The Nano-Stethoscope uses the conventional scanning feature to locate a desired site, positions the AFM microscope tip over the site, holds the cantilever stationary (in x and v) and records the tip`s z-motion as a function of time. The tip/cantilever system thus functions as a micro-motion detector to respond to characteristic {open_quotes}pulsations{close_quotes}, nano-configurational chances, or any other event that influences the position of the tip as a function of time. The authors have demonstrated the feasibility of using the tip of an AFM in this manner in a biological system with a measurement of the vibrations of an emerging shrimp egg nauplius ({approximately}3 {mu}m. -10 Hz) and on the Angstrom scale in a non-biological system i.e.. the thermal expansion of metal interconnect lines on a microelectronic circuit.

  8. Surface features on Sahara soil dust particles made visible by atomic force microscope (AFM phase images

    Directory of Open Access Journals (Sweden)

    M. O. Andreae

    2008-10-01

    Full Text Available We show that atomic force microscopy (AFM phase images can reveal surface features of soil dust particles, which are not evident using other microscopic methods. The non-contact AFM method is able to resolve topographical structures in the nanometer range as well as to uncover repulsive atomic forces and attractive van der Waals' forces, and thus gives insight to surface properties. Though the method does not allow quantitative assignment in terms of chemical compound description, it clearly shows deposits of distinguishable material on the surface. We apply this technique to dust aerosol particles from the Sahara collected over the Atlantic Ocean and describe micro-features on the surfaces of such particles.

  9. Investigation of specific interactions between T7 promoter and T7 RNA polymerase by force spectroscopy using atomic force microscope.

    Science.gov (United States)

    Zhang, Xiaojuan; Yao, Zhixuan; Duan, Yanting; Zhang, Xiaomei; Shi, Jinsong; Xu, Zhenghong

    2018-01-11

    The specific recognition and binding of promoter and RNA polymerase is the first step of transcription initiation in bacteria and largely determines transcription activity. Therefore, direct analysis of the interaction between promoter and RNA polymerase in vitro may be a new strategy for promoter characterization, to avoid interference due to the cell's biophysical condition and other regulatory elements. In the present study, the specific interaction between T7 promoter and T7 RNA polymerase was studied as a model system using force spectroscopy based on atomic force microscope (AFM). The specific interaction between T7 promoter and T7 RNA polymerase was verified by control experiments, and the rupture force in this system was measured as 307.2 ± 6.7 pN. The binding between T7 promoter mutants with various promoter activities and T7 RNA polymerase was analyzed. Interaction information including rupture force, rupture distance and binding percentage were obtained in vitro , and reporter gene expression regulated by these promoters was also measured according to a traditional promoter activity characterization method in vivo Using correlation analysis, it was found that the promoter strength characterized by reporter gene expression was closely correlated with rupture force and the binding percentage by force spectroscopy. These results indicated that the analysis of the interaction between promoter and RNA polymerase using AFM-based force spectroscopy was an effective and valid approach for the quantitative characterization of promoters. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  10. A compact CCD-monitored atomic force microscope with optical vision and improved performances.

    Science.gov (United States)

    Mingyue, Liu; Haijun, Zhang; Dongxian, Zhang

    2013-09-01

    A novel CCD-monitored atomic force microscope (AFM) with optical vision and improved performances has been developed. Compact optical paths are specifically devised for both tip-sample microscopic monitoring and cantilever's deflection detecting with minimized volume and optimal light-amplifying ratio. The ingeniously designed AFM probe with such optical paths enables quick and safe tip-sample approaching, convenient and effective tip-sample positioning, and high quality image scanning. An image stitching method is also developed to build a wider-range AFM image under monitoring. Experiments show that this AFM system can offer real-time optical vision for tip-sample monitoring with wide visual field and/or high lateral optical resolution by simply switching the objective; meanwhile, it has the elegant performances of nanometer resolution, high stability, and high scan speed. Furthermore, it is capable of conducting wider-range image measurement while keeping nanometer resolution. Copyright © 2013 Wiley Periodicals, Inc.

  11. Experimental Implementation of a Model-Based Inverse Filter to Attenuate Hysteresis in an Atomic Force Microscope

    National Research Council Canada - National Science Library

    Hatch, Andrew; Smith, Ralph G; De, Tathagata

    2004-01-01

    This paper addresses the development and experimental validation of a model-based, open loop control design for mitigating the frequency-dependent effects of hysteresis in an atomic force microscope (AFM...

  12. Tip localization of an atomic force microscope in transmission microscopy with nanoscale precision.

    Science.gov (United States)

    Baumann, Fabian; Heucke, Stephan F; Pippig, Diana A; Gaub, Hermann E

    2015-03-01

    Since the atomic force microscope (AFM) has evolved into a general purpose platform for mechanical experiments at the nanoscale, the need for a simple and generally applicable localization of the AFM cantilever in the reference frame of an optical microscope has grown. Molecular manipulations like in single molecule cut and paste or force spectroscopy as well as tip mediated nanolithography are prominent examples for the broad variety of applications implemented to date. In contrast to the different kinds of superresolution microscopy where fluorescence is used to localize the emitter, we, here, employ the absorbance of the tip to localize its position in transmission microscopy. We show that in a low aperture illumination, the tip causes a significant reduction of the intensity in the image plane of the microscope objective when it is closer than a few hundred nm. By independently varying the z-position of the sample slide, we could verify that this diffraction limited image of the tip is not caused by a near field effect but is rather caused by the absorbance of the transmitted light in the low apex needle-like tip. We localized the centroid position of this tip image with a precision of better than 6 nm and used it in a feedback loop to position the tip into nano-apertures of 110 nm radius. Single-molecule force spectroscopy traces on the unfolding of individual green fluorescent proteins within the nano-apertures showed that their center positions were repeatedly approached with very high fidelity leaving the specific handle chemistry on the tip's surface unimpaired.

  13. Tip localization of an atomic force microscope in transmission microscopy with nanoscale precision

    Science.gov (United States)

    Baumann, Fabian; Heucke, Stephan F.; Pippig, Diana A.; Gaub, Hermann E.

    2015-03-01

    Since the atomic force microscope (AFM) has evolved into a general purpose platform for mechanical experiments at the nanoscale, the need for a simple and generally applicable localization of the AFM cantilever in the reference frame of an optical microscope has grown. Molecular manipulations like in single molecule cut and paste or force spectroscopy as well as tip mediated nanolithography are prominent examples for the broad variety of applications implemented to date. In contrast to the different kinds of superresolution microscopy where fluorescence is used to localize the emitter, we, here, employ the absorbance of the tip to localize its position in transmission microscopy. We show that in a low aperture illumination, the tip causes a significant reduction of the intensity in the image plane of the microscope objective when it is closer than a few hundred nm. By independently varying the z-position of the sample slide, we could verify that this diffraction limited image of the tip is not caused by a near field effect but is rather caused by the absorbance of the transmitted light in the low apex needle-like tip. We localized the centroid position of this tip image with a precision of better than 6 nm and used it in a feedback loop to position the tip into nano-apertures of 110 nm radius. Single-molecule force spectroscopy traces on the unfolding of individual green fluorescent proteins within the nano-apertures showed that their center positions were repeatedly approached with very high fidelity leaving the specific handle chemistry on the tip's surface unimpaired.

  14. Combining atomic force microscope and quartz crystal microbalance studies for cell detection

    Science.gov (United States)

    Hayden, Oliver; Bindeus, Roland; Dickert, Franz L.

    2003-11-01

    The adhesion of microorganisms on a patterned polyurethane surface was studied simultaneously online and in situ with a quartz crystal microbalance (QCM) and an atomic force microscope (AFM). The specific interaction between Saccharomyces cerevisiae cells and their fingerprints formed by molecular imprinting results in a typical Sauerbrey behaviour, when adhesion events are observable with an AFM. The sensor response due to adsorption of Gram positive Leuconostoc oenus, however, shows non-Sauerbrey behaviour. Bacteria, naturally being smaller than yeast cells, were 'invisible' to liquid phase AFM-measurements, which is due to a weaker surface interaction. Thus, AFM measurements give a hint for unusual frequency enhancements in QCM microorganism measurements.

  15. Optimization of Easy Atomic Force Microscope (ezAFM) Controls for Semiconductor Nanostructure Profiling

    Science.gov (United States)

    2017-09-01

    Laboratory recently procured an Easy Atomic Force Microscope (ezAFM), from a NanoMagnetics vendor. The ezAFM can profile nanostructures on the order of 2.0 Å...just as previous AFMs do. This allows for scans of possible defects of sample surfaces, as well as displays of changes in topography. In using the...the cross-sectional graph provides an approximation of the noise. Less than 2 Å is ideal. It is possible to observe relative noise by observing the

  16. Reliable measurement of elastic modulus of cells by nanoindentation in an atomic force microscope

    KAUST Repository

    Zhou, Zhoulong

    2012-04-01

    The elastic modulus of an oral cancer cell line UM1 is investigated by nanoindentation in an atomic force microscope with a flat-ended tip. The commonly used Hertzian method gives apparent elastic modulus which increases with the loading rate, indicating strong effects of viscoelasticity. On the contrary, a rate-jump method developed for viscoelastic materials gives elastic modulus values which are independent of the rate-jump magnitude. The results show that the rate-jump method can be used as a standard protocol for measuring elastic stiffness of living cells, since the measured values are intrinsic properties of the cells. © 2011 Elsevier Ltd.

  17. 3D mechanical measurements with an atomic force microscope on 1D structures

    DEFF Research Database (Denmark)

    Kallesøe, Christian; Larsen, Martin Benjamin Barbour Spanget; Bøggild, Peter

    2012-01-01

    We have developed a simple method to characterize the mechanical properties of three dimensional nanostructures, such as nanorods standing up from a substrate. With an atomic force microscope the cantilever probe is used to deflect a horizontally aligned nanorod at different positions along...... the nanorod, using the apex of the cantilever itself rather than the tip normally used for probing surfaces. This enables accurate determination of nanostructures' spring constant. From these measurements, Young's modulus is found on many individual nanorods with different geometrical and material structures...... in a short time. Based on this method Young's modulus of carbon nanofibers and epitaxial grown III-V nanowires has been determined....

  18. Building a multi-walled carbon nanotube-based mass sensor with the atomic force microscope

    DEFF Research Database (Denmark)

    Mateiu, Ramona Valentina; Kuhle, A.; Marie, Rodolphe Charly Willy

    2005-01-01

    are used. The gold substrate is first covered with hydrophobic thiol molecules: octadecanthiol. The octadecanthiol molecules are then selectively removed from small areas by nanoshaving the gold substrate with the tip of an atomic force microscope (AFM) operating in contact mode. Hydrophilic thiols (2......We report an approach for building a mass sensor based on multi-walled carbon nanotubes (MWCNT). We propose a method with a great potential for the positioning of MWCNTs based on self-assembly onto patterned hydrophilic areas. For the experiments ultra flat mica substrates covered with gold...

  19. Surface topography characterization using an atomic force microscope mounted on a coordinate measuring machine

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo; Hansen, H.N; Kofod, N

    1999-01-01

    The paper describes the construction, testing and use of an integrated system for topographic characterization of fine surfaces on parts having relatively big dimensions. An atomic force microscope (AFM) was mounted on a manual three-coordinate measuring machine (CMM) achieving free positioning...... of the AFM probe in space. This means that the limited measuring range of the AFM (40 mu m x 40 mu m x 2.7 um) can be extended by positioning the AFM probe using the movements of the CMM axes (400 mm x 100 mm x 75 mm). Evaluation of the background noise by determining the Sa value of an optical fiat gave...

  20. Multifractal spectra of atomic force microscope images of amorphous electroless Ni Cu P alloy

    Science.gov (United States)

    Yu, Hui-Sheng; Sun, Xia; Luo, Shou-Fu; Wang, Yong-Rui; Wu, Zi-Qin

    2002-05-01

    The surface topographies of Si/TiN/Pd substrate and amorphous electroless Ni-13.1 wt.% Cu-9.3 wt.% P alloy deposited for various times were measured by atomic force microscope (AFM). Multifractal spectra f( α) show that the longer the deposition time, the wider the spectrum, and the larger the Δ f (Δ f= f( αmin)- f( αmax)). It is apparent that the nonuniformity of the height distribution increases with the increasing deposition time, and the nodules of Ni-Cu-P alloy grow in both horizontal and vertical way. These results show that the AFM images can be characterized by the multifractal spectra.

  1. Track sensitivity and the surface roughness measurements of CR-39 with atomic force microscope

    CERN Document Server

    Yasuda, N; Amemiya, K; Takahashi, H; Kyan, A; Ogura, K

    1999-01-01

    Atomic Force Microscope (AFM) has been applied to evaluate the surface roughness and the track sensitivity of CR-39 track detector. We experimentally confirmed the inverse correlation between the track sensitivity and the roughness of the detector surface after etching. The surface of CR-39 (CR-39 doped with antioxidant (HARZLAS (TD-1)) and copolymer of CR-39/NIPAAm (TNF-1)) with high sensitivity becomes rough by the etching, while the pure CR-39 (BARYOTRAK) with low sensitivity keeps its original surface clarity even for the long etching.

  2. Micromechanical contact stiffness devices and application for calibrating contact resonance atomic force microscopy.

    Science.gov (United States)

    Rosenberger, Matthew R; Chen, Sihan; Prater, Craig B; King, William P

    2017-01-27

    This paper reports the design, fabrication, and characterization of micromechanical devices that can present an engineered contact stiffness to an atomic force microscope (AFM) cantilever tip. These devices allow the contact stiffness between the AFM tip and a substrate to be easily and accurately measured, and can be used to calibrate the cantilever for subsequent mechanical property measurements. The contact stiffness devices are rigid copper disks of diameters 2-18 μm integrated onto a soft silicone substrate. Analytical modeling and finite element simulations predict the elastic response of the devices. Measurements of tip-sample interactions during quasi-static force measurements compare well with modeling simulation, confirming the expected elastic response of the devices, which are shown to have contact stiffness 32-156 N m(-1). To demonstrate one application, we use the disk sample to calibrate three resonant modes of a U-shaped AFM cantilever actuated via Lorentz force, at approximately 220, 450, and 1200 kHz. We then use the calibrated cantilever to determine the contact stiffness and elastic modulus of three polymer samples at these modes. The overall approach allows cantilever calibration without prior knowledge of the cantilever geometry or its resonance modes, and could be broadly applied to both static and dynamic measurements that require AFM calibration against a known contact stiffness.

  3. Role of geometry on the frequency spectra of U-shaped atomic force microscope probes

    Science.gov (United States)

    Rezaei, E.; Turner, J. A.

    2017-02-01

    Contact resonance atomic force microscopy (CR-AFM) is a specific technique that is used to determine elastic or viscoelastic properties of materials. The success of this technique is highly dependent on the accuracy of frequency spectra that must be measured for both noncontact and the case in which the tip is in contact with the sample of interest. Thus, choosing the right probe is crucial for accurate experiments. U-shaped probes also offer new opportunities for CR-AFM measurements because of certain specific modes that have tip motion parallel to the sample surface such that these resonances can access in-plane sample properties. However, analysis of the spectra from U-shaped probes is much more challenging due to these modes. The geometry of these probes is the main driver for the spectral response. Here, this influence on the resonance frequencies of the commercially fabricated U-shaped probe AN2-300 is evaluated with respect to geometry in terms of leg width, crossbeam width, and crossbeam length. Both noncontact and contact cases are examined with respect to variations of the nominal geometry. An energy distribution approach is also presented to assist with the identification of modes that have close resonances. Finally, this analysis allows recommendations to be made in order to minimize the convergence of multiple resonances for a specific range of measurement parameters.

  4. Quantitative measurements of electromechanical response with a combined optical beam and interferometric atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Labuda, Aleksander; Proksch, Roger [Asylum Research an Oxford Instruments Company, Santa Barbara, California 93117 (United States)

    2015-06-22

    An ongoing challenge in atomic force microscope (AFM) experiments is the quantitative measurement of cantilever motion. The vast majority of AFMs use the optical beam deflection (OBD) method to infer the deflection of the cantilever. The OBD method is easy to implement, has impressive noise performance, and tends to be mechanically robust. However, it represents an indirect measurement of the cantilever displacement, since it is fundamentally an angular rather than a displacement measurement. Here, we demonstrate a metrological AFM that combines an OBD sensor with a laser Doppler vibrometer (LDV) to enable accurate measurements of the cantilever velocity and displacement. The OBD/LDV AFM allows a host of quantitative measurements to be performed, including in-situ measurements of cantilever oscillation modes in piezoresponse force microscopy. As an example application, we demonstrate how this instrument can be used for accurate quantification of piezoelectric sensitivity—a longstanding goal in the electromechanical community.

  5. Biophysical Measurements of Cells, Microtubules, and DNA with an Atomic Force Microscope

    CERN Document Server

    Devenica, Luka M; Cabrejo, Raysa; Kurek, Matthew; Deveney, Edward F; Carter, Ashley R

    2015-01-01

    Atomic force microscopes (AFMs) are ubiquitous in research laboratories and have recently been priced for use in teaching laboratories. Here we review several AFM platforms (Dimension 3000 by Digital Instruments, EasyScan2 by Nanosurf, ezAFM by Nanomagnetics, and TKAFM by Thorlabs) and describe various biophysical experiments that could be done in the teaching laboratory using these instruments. In particular, we focus on experiments that image biological materials and quantify biophysical parameters: 1) imaging cells to determine membrane tension, 2) imaging microtubules to determine their persistence length, 3) imaging the random walk of DNA molecules to determine their contour length, and 4) imaging stretched DNA molecules to measure the tensional force.

  6. Quantitative measurements of electromechanical response with a combined optical beam and interferometric atomic force microscope

    Science.gov (United States)

    Labuda, Aleksander; Proksch, Roger

    2015-06-01

    An ongoing challenge in atomic force microscope (AFM) experiments is the quantitative measurement of cantilever motion. The vast majority of AFMs use the optical beam deflection (OBD) method to infer the deflection of the cantilever. The OBD method is easy to implement, has impressive noise performance, and tends to be mechanically robust. However, it represents an indirect measurement of the cantilever displacement, since it is fundamentally an angular rather than a displacement measurement. Here, we demonstrate a metrological AFM that combines an OBD sensor with a laser Doppler vibrometer (LDV) to enable accurate measurements of the cantilever velocity and displacement. The OBD/LDV AFM allows a host of quantitative measurements to be performed, including in-situ measurements of cantilever oscillation modes in piezoresponse force microscopy. As an example application, we demonstrate how this instrument can be used for accurate quantification of piezoelectric sensitivity—a longstanding goal in the electromechanical community.

  7. Dielectrophoretic positioning of single nanoparticles on atomic force microscope tips for tip-enhanced Raman spectroscopy.

    Science.gov (United States)

    Leiterer, Christian; Deckert-Gaudig, Tanja; Singh, Prabha; Wirth, Janina; Deckert, Volker; Fritzsche, Wolfgang

    2015-05-01

    Tip-enhanced Raman spectroscopy, a combination of Raman spectroscopy and scanning probe microscopy, is a powerful technique to detect the vibrational fingerprint of molecules at the nanometer scale. A metal nanoparticle at the apex of an atomic force microscope tip leads to a large enhancement of the electromagnetic field when illuminated with an appropriate wavelength, resulting in an increased Raman signal. A controlled positioning of individual nanoparticles at the tip would improve the reproducibility of the probes and is quite demanding due to usually serial and labor-intensive approaches. In contrast to commonly used submicron manipulation techniques, dielectrophoresis allows a parallel and scalable production, and provides a novel approach toward reproducible and at the same time affordable tip-enhanced Raman spectroscopy tips. We demonstrate the successful positioning of an individual plasmonic nanoparticle on a commercial atomic force microscope tip by dielectrophoresis followed by experimental proof of the Raman signal enhancing capabilities of such tips. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Re-calibration of the NIST SRM 2059 master standard using traceable atomic force microscope metrology

    Science.gov (United States)

    Dixson, Ronald; Potzick, James; Orji, Ndubuisi G.

    2008-10-01

    The current photomask linewidth Standard Reference Material (SRM) supplied by the National Institute of Standards and Technology (NIST), SRM 2059, is the fifth generation of such standards for mask metrology. An in house optical microscope tool developed at NIST, called the NIST ultra-violet (UV) microscope, was used in transmission mode to calibrate the SRM 2059 photomasks. Due to the limitations of available optical models for determining the edge response in the UV microscope, the tool was used in a comparator mode. One of the masks was selected as a master standard - and the features on this mask were calibrated using traceable critical dimension atomic force microscope (CD-AFM) dimensional metrology. The optical measurements were then used to determine the relative offsets between the widths on the master standard and individual masks for sale to customers. At the time of these measurements, however, the uncertainties in the CD-AFM reference metrology on the master standard were larger than can now be achieved because the NIST single crystal critical dimension reference material (SCCDRM) project had not been completed. Using our CD-AFM at NIST, we have performed new measurements on the SRM 2059 master standard. The new AFM results are in agreement with the prior measurements and have expanded uncertainties approximately one fourth of those of the earlier results for sub-micrometer features. When the optical comparator data for customers masks are reanalyzed using these new AFM results, we expect to reduce the combined reported uncertainties for the linewidths on the actual SRMs by at least 40 % for the nominal 0.25 μm features.

  9. Resonant scattering and microscopic model of spinless Fermi gases in one-dimensional optical lattices

    Science.gov (United States)

    Cui, Xiaoling

    2017-04-01

    We study the effective Bloch-wave scattering of a spinless Fermi gas in one-dimensional (1D) optical lattices. By tuning the odd-wave scattering length, we find multiple resonances of Bloch waves scattering at the bottom (and the top) of the lowest band, beyond which an attractive (and a repulsive) two-body bound state starts to emerge. These resonances exhibit comparable widths in the deep lattice limit, and the finite interaction range plays an essential role in determining their locations. Based on exact two-body solutions, we construct an effective microscopic model for the low-energy scattering of fermions. The model can reproduce not only the scattering amplitudes of Bloch waves at the lowest-band bottom or top, but also the attractive or repulsive bound states within a reasonably large energy range below or above the band. These results lay the foundation for quantum simulating topological states in cold Fermi gases confined in 1D optical lattices.

  10. High sensitivity detection of protein molecules picked up on a probe of atomic force microscope based on the fluorescence detection by a total internal reflection fluorescence microscope.

    Science.gov (United States)

    Yamada, Takafumi; Afrin, Rehana; Arakawa, Hideo; Ikai, Atsushi

    2004-07-02

    We developed a method to detect and identify proteins on a probe of the atomic force microscope (AFM) with a high sensitivity. Due to a low background noise of the total internal reflection fluorescence microscope employed as a detecting system, we were able to achieve a high enough sensitivity to detect zeptomole orders of protein molecules immobilized on the tip. Several different methods to immobilize protein molecules to AFM-probes were tested, meant for a wide range of applications of this method. Furthermore, we demonstrated that different proteins were clearly distinguished by immunofluorescence microscopy on the probe using their specific antibodies.

  11. Combination of Universal Mechanical Testing Machine with Atomic Force Microscope for Materials Research

    Science.gov (United States)

    Zhong, Jian; He, Dannong

    2015-08-01

    Surface deformation and fracture processes of materials under external force are important for understanding and developing materials. Here, a combined horizontal universal mechanical testing machine (HUMTM)-atomic force microscope (AFM) system is developed by modifying UMTM to combine with AFM and designing a height-adjustable stabilizing apparatus. Then the combined HUMTM-AFM system is evaluated. Finally, as initial demonstrations, it is applied to analyze the relationship among macroscopic mechanical properties, surface nanomorphological changes under external force, and fracture processes of two kinds of representative large scale thin film materials: polymer material with high strain rate (Parafilm) and metal material with low strain rate (aluminum foil). All the results demonstrate the combined HUMTM-AFM system overcomes several disadvantages of current AFM-combined tensile/compression devices including small load force, incapability for large scale specimens, disability for materials with high strain rate, and etc. Therefore, the combined HUMTM-AFM system is a promising tool for materials research in the future.

  12. Optical pulling force and conveyor belt effect in resonator-waveguide system.

    Science.gov (United States)

    Intaraprasonk, Varat; Fan, Shanhui

    2013-09-01

    We present the theoretical condition and actual numerical design that achieves an optical pulling force in resonator-waveguide systems, where the direction of the force on the resonator is in the opposite direction to the input light in the waveguide. We also show that this pulling force can occur in conjunction with the lateral optical equilibrium effect, such that the resonator is maintained at the fixed distance from the waveguide while experiencing the pulling force.

  13. Characterizing absolute piezoelectric microelectromechanical system displacement using an atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Evans, J., E-mail: radiant@ferrodevices.com; Chapman, S., E-mail: radiant@ferrodevices.com [Radiant Technologies, Inc., 2835C Pan American Fwy NE, Albuquerque, New Mexico 87107 (United States)

    2014-08-14

    Piezoresponse Force Microscopy (PFM) is a popular tool for the study of ferroelectric and piezoelectric materials at the nanometer level. Progress in the development of piezoelectric MEMS fabrication is highlighting the need to characterize absolute displacement at the nanometer and Ångstrom scales, something Atomic Force Microscopy (AFM) might do but PFM cannot. Absolute displacement is measured by executing a polarization measurement of the ferroelectric or piezoelectric capacitor in question while monitoring the absolute vertical position of the sample surface with a stationary AFM cantilever. Two issues dominate the execution and precision of such a measurement: (1) the small amplitude of the electrical signal from the AFM at the Ångstrom level and (2) calibration of the AFM. The authors have developed a calibration routine and test technique for mitigating the two issues, making it possible to use an atomic force microscope to measure both the movement of a capacitor surface as well as the motion of a micro-machine structure actuated by that capacitor. The theory, procedures, pitfalls, and results of using an AFM for absolute piezoelectric measurement are provided.

  14. Piezoelectric bimorph-based scanner in the tip-scan mode for high speed atomic force microscope.

    Science.gov (United States)

    Zhao, Jianyong; Gong, Weitao; Cai, Wei; Shang, Guangyi

    2013-08-01

    A piezoelectric bimorph-based scanner operating in tip-scan mode for high speed atomic force microscope (AFM) is first presented. The free end of the bimorph is used for fixing an AFM cantilever probe and the other one is mounted on the AFM head. The sample is placed on the top of a piezoelectric tube scanner. High speed scan is performed with the bimorph that vibrates at the resonant frequency, while slow scanning is carried out by the tube scanner. The design and performance of the scanner is discussed and given in detailed. Combined with a commercially available data acquisition system, a high speed AFM has been built successfully. By real-time observing the deformation of the pores on the surface of a commercial piezoelectric lead zirconate titanate (PZT-5) ceramics under electric field, the dynamic imaging capability of the AFM is demonstrated. The results show that the notable advantage of the AFM is that dynamic process of the sample with large dimensions can be easily investigated. In addition, this design could provide a way to study a sample in real time under the given experimental condition, such as under an external electric field, on a heating stage, or in a liquid cell.

  15. Sensorless enhancement of an atomic force microscope micro-cantilever quality factor using piezoelectric shunt control.

    Science.gov (United States)

    Fairbairn, M; Moheimani, S O R

    2013-05-01

    The image quality and resolution of the Atomic Force Microscope (AFM) operating in tapping mode is dependent on the quality (Q) factor of the sensing micro-cantilever. Increasing the cantilever Q factor improves image resolution and reduces the risk of sample and cantilever damage. Active piezoelectric shunt control is introduced in this work as a new technique for modifying the Q factor of a piezoelectric self-actuating AFM micro-cantilever. An active impedance is placed in series with the tip oscillation voltage source to modify the mechanical dynamics of the cantilever. The benefit of using this control technique is that it removes the optical displacement sensor from the Q control feedback loop to reduce measurement noise in the loop and allows for a reduction in instrument size.

  16. Nanometer-scale lithography of ultrathin films with atomic force microscope

    CERN Document Server

    Kim, J C; Shin, Y W; Park, S W

    1998-01-01

    Ultrathin resist films have been prepared by both Langmuir-Blodgett (LB) and self-assembly (SA) techniques. Nanometer-scale patterning of these thin films has been performed by using the atomic force microscope (AFM) as the exposing tool. The poly (methylphenylmethacrylate) (PMPMA) LB films were prepared and fabricated by AFM lithography. When the exposure was carried out at the bias voltage of -25V, the protruding lines appeared in the exposed regions. The preoptimized LB films at various conditions exhibited 120 nm line resolution. An organosilane monolayer composed of octadecyldimethylsilyl groups was prepared on a Si substrate. It was then patterned through the localized degradation of the monolayer due to anodic reaction induced by an AFM tip. When the bias voltage was -30 V, the protruding lines appeared in the exposed regions.

  17. Site-controlled quantum dots fabricated using an atomic-force microscope assisted technique

    Directory of Open Access Journals (Sweden)

    Sakuma Y

    2006-01-01

    Full Text Available AbstractAn atomic-force microscope assisted technique is developed to control the position and size of self-assembled semiconductor quantum dots (QDs. Presently, the site precision is as good as ± 1.5 nm and the size fluctuation is within ± 5% with the minimum controllable lateral diameter of 20 nm. With the ability of producing tightly packed and differently sized QDs, sophisticated QD arrays can be controllably fabricated for the application in quantum computing. The optical quality of such site-controlled QDs is found comparable to some conventionally self-assembled semiconductor QDs. The single dot photoluminescence of site-controlled InAs/InP QDs is studied in detail, presenting the prospect to utilize them in quantum communication as precisely controlled single photon emitters working at telecommunication bands.

  18. The relation of apple texture with cell wall nanostructure studied using an atomic force microscope.

    Science.gov (United States)

    Cybulska, Justyna; Zdunek, Artur; Psonka-Antonczyk, Katarzyna M; Stokke, Bjørn T

    2013-01-30

    In this study, the relation of the nanostructure of cell walls with their texture was investigated for six different apple cultivars. Cell wall material (CWM) and cellulose microfibrils were imaged by atomic force microscope (AFM). The mean diameter of cellulose microfibrils for each cultivar was estimated based on the AFM height topographs obtained using the tapping mode of dried specimens. Additionally, crystallinity of cellulose microfibrils and pectin content was determined. Texture of apple cultivars was evaluated by sensory and instrumental analysis. Differences in cellulose diameter as determined from the AFM height topographs of the nanostructure of cell walls of the apple cultivars are found to relate to the degree of crystallinity and pectin content. Cultivars with thicker cellulose microfibrils also revealed crisper, harder and juicier texture, and greater acoustic emission. The data suggest that microfibril thickness affects the mechanical strength of cell walls which has consequences for sensory and instrumental texture. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Serum induced degradation of 3D DNA box origami observed by high speed atomic force microscope

    DEFF Research Database (Denmark)

    Jiang, Zaixing; Zhang, Shuai; Yang, Chuanxu

    2015-01-01

    3D DNA origami holds tremendous potential to encapsulate and selectively release therapeutic drugs. Observations of real-time performance of 3D DNA origami structures in physiological environment will contribute much to its further applications. Here, we investigate the degradation kinetics of 3D...... DNA box origami in serum using high-speed atomic force microscope optimized for imaging 3D DNA origami in real time. The time resolution allows characterizing the stages of serum effects on individual 3D DNA box origami with nanometer resolution. Our results indicate that the whole digest process...... is a combination of a rapid collapse phase and a slow degradation phase. The damages of box origami mainly happen in the collapse phase. Thus, the structure stability of 3D DNA box origami should be further improved, especially in the collapse phase, before clinical applications...

  20. Novel dual-probes atomic force microscope for line width measurements

    Science.gov (United States)

    Wang, Hequn; Gao, Sitian; Li, Wei; Shi, Yushu; Li, Qi; Li, Shi

    2017-11-01

    Dual-probe Atomic Force Microscope (AFM) can effectively eliminate the influence of the probe size on measurement of the line width, and realize true three-dimensional measurement. Novel dual-probe AFM consists of probe system, scanning system, alignment system and displacement measurement system. As displacement measurement system, the interferometers are added to the novel dual-probes AFM. In order to simplify the dual-probe AFM structure, self-sensing tuning fork probe is used. Measurement method has two steps: the first step is to align two probes and obtain the reference point; the second step is to scan two sides of measured line by two probes separately, and calculate the line width value according to the reference point. In the alignment of two probes, the alignment method is improved by using the edge alignment and the feedback scanning alignment.

  1. Wet-chemical nanoscale patterning of GaAs surfaces using atomic force microscope lithography

    Science.gov (United States)

    Klehn, B.; Skaberna, S.; Kunze, U.

    1999-01-01

    Sub-100 nm V-grooves in GaAs(001) surfaces have been fabricated by patterning a thin photoresist layer with an atomic force microscope (AFM) and subsequent wet-chemical etching. The nanolithography is based on the dynamic ploughing technique. Anisotropic etchants under investigation are bromine-methanol-isopropanol, sulfuric acid-hydrogen peroxide-water, citric acid-hydrogen peroxide-water, and ammonium hydroxide-hydrogen peroxide-water. Along the [11¯0] direction the etched grooves are V-shaped, along [11¯0] the profile is U-shaped. Best results of 50-60-nm wide V-grooves with straight edges and smooth sidewalls are obtained from bromine-methanol-isopropanol, the other etchants form rough grooves. Concerning the reproducibility of the patterning process, the aqueous etch solutions exceed the bromine etchant.

  2. A Correlative Defect Analyzer Combining Glide Test with Atomic Force Microscope

    Directory of Open Access Journals (Sweden)

    Jizhong He

    2013-01-01

    Full Text Available We have developed a novel instrument combining a glide tester with an Atomic Force Microscope (AFM for hard disk drive (HDD media defect test and analysis. The sample stays on the same test spindle during both glide test and AFM imaging without losing the relevant coordinates. This enables an in situ evaluation with the high-resolution AFM of the defects detected by the glide test. The ability for the immediate follow-on AFM analysis solves the problem of relocating the defects quickly and accurately in the current workflow. The tool is furnished with other functions such as scribing, optical imaging, and head burnishing. Typical data generated from the tool are shown at the end of the paper. It is further demonstrated that novel experiments can be carried out on the platform by taking advantage of the correlative capabilities of the tool.

  3. Direct observation of phase transition of GeSbTe thin films by Atomic Force Microscope

    Energy Technology Data Exchange (ETDEWEB)

    Yang Fei [National Laboratory of Solid State Microstructures and Jiangsu Provincial Key Laboratory of Photonic and Electronic Materials Sciences and Technology, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Xu Ling, E-mail: xuling@nju.edu.cn [National Laboratory of Solid State Microstructures and Jiangsu Provincial Key Laboratory of Photonic and Electronic Materials Sciences and Technology, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Zhang Rui; Geng Lei; Tong Liang; Xu Jun [National Laboratory of Solid State Microstructures and Jiangsu Provincial Key Laboratory of Photonic and Electronic Materials Sciences and Technology, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Su Weining; Yu Yao [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Ma Zhongyuan; Chen Kunji [National Laboratory of Solid State Microstructures and Jiangsu Provincial Key Laboratory of Photonic and Electronic Materials Sciences and Technology, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China)

    2012-10-01

    Graphical abstract: Nano-sized marks on GST thin film were fabricated using Conductive-AFM (Atomic Force Microscope). The AFM morphology images show that the marks are ablated at the center and a raised ring surrounding it. Highlights: Black-Right-Pointing-Pointer Microstructure of GeSbTe thin films was characterized by XRD and AFM. Black-Right-Pointing-Pointer Annealing and applying electrical field can induce crystallization on thin film. Black-Right-Pointing-Pointer Conductive-AFM was used to modify the surface of GeSbTe thin film. - Abstract: GeSbTe (GST) thin films were deposited on quartz substrates using electron beam evaporation system and then annealed in nitrogen atmosphere at different temperatures, ranging from 20 Degree-Sign C to 300 Degree-Sign C. X-ray diffraction (XRD) and Atomic Force microscope (AFM) measurements were used to characterize the as-deposited and post-annealed thin films. Annealing treatment was found to induce changes on microstructure, surface roughness and grain size, indicating that with the increase of annealing temperature, the amorphous GST films first changed to face-centered-cubic (fcc) phase and then the stable hexagonal (hex) phase. Meanwhile, conductive-AFM (C-AFM) was used to produce crystallized GST dots on thin films. I-V spectroscopy results show that GST films can switch from amorphous state to crystalline state at threshold voltage. After switching, I-V curve exhibits ohmic characteristic, which is usually observed in crystallized GST films. By applying repeated I-V spectroscopies on the thin films, crystallized nuclei were observed. As the times of I-V spectroscopies increases, the area of written dots increases, and the center of the mark begin to ablate. The AFM images show that the shape of marks is an ablated center with a raised ring surrounding it.

  4. Atomic Force Microscope nanolithography on chromosomes to generate single-cell genetic probes

    Directory of Open Access Journals (Sweden)

    Valle Francesco

    2011-06-01

    Full Text Available Abstract Background Chromosomal dissection provides a direct advance for isolating DNA from cytogenetically recognizable region to generate genetic probes for fluorescence in situ hybridization, a technique that became very common in cyto and molecular genetics research and diagnostics. Several reports describing microdissection methods (glass needle or a laser beam to obtain specific probes from metaphase chromosomes are available. Several limitations are imposed by the traditional methods of dissection as the need for a large number of chromosomes for the production of a probe. In addition, the conventional methods are not suitable for single chromosome analysis, because of the relatively big size of the microneedles. Consequently new dissection techniques are essential for advanced research on chromosomes at the nanoscale level. Results We report the use of Atomic Force Microscope (AFM as a tool for nanomanipulation of single chromosomes to generate individual cell specific genetic probes. Besides new methods towards a better nanodissection, this work is focused on the combination of molecular and nanomanipulation techniques which enable both nanodissection and amplification of chromosomal and chromatidic DNA. Cross-sectional analysis of the dissected chromosomes reveals 20 nm and 40 nm deep cuts. Isolated single chromosomal regions can be directly amplified and labeled by the Degenerate Oligonucleotide-Primed Polymerase Chain Reaction (DOP-PCR and subsequently hybridized to chromosomes and interphasic nuclei. Conclusions Atomic force microscope can be easily used to visualize and to manipulate biological material with high resolution and accuracy. The fluorescence in situ hybridization (FISH performed with the DOP-PCR products as test probes has been tested succesfully in avian microchromosomes and interphasic nuclei. Chromosome nanolithography, with a resolution beyond the resolution limit of light microscopy, could be useful to the

  5. Calibration of an interfacial force microscope for MEMS metrology : FY08-09 activities.

    Energy Technology Data Exchange (ETDEWEB)

    Houston, Jack E.; Baker, Michael Sean; Crowson, Douglas A.; Mitchell, John Anthony; Moore, Nathan W.

    2009-10-01

    Progress in MEMS fabrication has enabled a wide variety of force and displacement sensing devices to be constructed. One device under intense development at Sandia is a passive shock switch, described elsewhere (Mitchell 2008). A goal of all MEMS devices, including the shock switch, is to achieve a high degree of reliability. This, in turn, requires systematic methods for validating device performance during each iteration of design. Once a design is finalized, suitable tools are needed to provide quality assurance for manufactured devices. To ensure device performance, measurements on these devices must be traceable to NIST standards. In addition, accurate metrology of MEMS components is needed to validate mechanical models that are used to design devices to accelerate development and meet emerging needs. Progress towards a NIST-traceable calibration method is described for a next-generation, 2D Interfacial Force Microscope (IFM) for applications in MEMS metrology and qualification. Discussed are the results of screening several suitable calibration methods and the known sources of uncertainty in each method.

  6. Determination of the Elastic Properties of Tomato Fruit Cells with an Atomic Force Microscope

    Directory of Open Access Journals (Sweden)

    Andrzej Kurenda

    2013-09-01

    Full Text Available Since the mechanical properties of single cells together with the intercellular adhesive properties determine the macro-mechanical properties of plants, a method for evaluation of the cell elastic properties is needed to help explanation of the behavior of fruits and vegetables in handling and food processing. For this purpose, indentation of tomato mesocarp cells with an atomic force microscope was used. The Young’s modulus of a cell using the Hertz and Sneddon models, and stiffness were calculated from force-indentation curves. Use of two probes of distinct radius of curvature (20 nm and 10,000 nm showed that the measured elastic properties were significantly affected by tip geometry. The Young’s modulus was about 100 kPa ± 35 kPa and 20 kPa ± 14 kPa for the sharper tip and a bead tip, respectively. Moreover, large variability regarding elastic properties (>100% among cells sampled from the same region in the fruit was observed. We showed that AFM provides the possibility of combining nano-mechanical properties with topography imaging, which could be very useful for the study of structure-related properties of fruits and vegetables at the cellular and sub-cellular scale.

  7. Comparison of line width calibration using critical dimension atomic force microscopes between PTB and NIST

    Science.gov (United States)

    Dai, Gaoliang; Hahm, Kai; Bosse, Harald; Dixson, Ronald G.

    2017-06-01

    International comparisons between National Metrology Institutes are important to verify measurement results and the associated uncertainties. In this paper, we report a comparison of the line width calibration of a crystalline silicon line width standard, referred to as IVPS100-PTB standard, between the Physikalisch-Technische Bundesanstalt in Germany and the National Institute of Standards and Technology in the United States. Critical dimension atomic force microscopy was the measurement method used for this comparison. Both institutes applied generally the same but independently developed traceability pathways: the scaling factor of the atomic force microscope (AFM) scanner was calibrated by a set of step height and lateral standards certified by metrological AFMs, while the effective tip width was ultimately traceable to the lattice parameter of silicon via high resolution transmission electron microscopy. Good agreement has been achieved in the comparison: For two groups of line features with nominal critical dimensions (CDs) of 50 nm, 70 nm, 90 nm, 110 nm and 130 nm that were compared, the observed deviations of CD results were between  -1.5 nm and 0.3 nm. The deviations are well within the associated measurement uncertainty.

  8. Mechanical Characterization of Tissue-Engineered Cartilage Using Microscopic Magnetic Resonance Elastography

    Science.gov (United States)

    Yin, Ziying; Schmid, Thomas M.; Yasar, Temel K.; Liu, Yifei; Royston, Thomas J.

    2014-01-01

    Knowledge of mechanical properties of tissue-engineered cartilage is essential for the optimization of cartilage tissue engineering strategies. Microscopic magnetic resonance elastography (μMRE) is a recently developed MR-based technique that can nondestructively visualize shear wave motion. From the observed wave pattern in MR phase images the tissue mechanical properties (e.g., shear modulus or stiffness) can be extracted. For quantification of the dynamic shear properties of small and stiff tissue-engineered cartilage, μMRE needs to be performed at frequencies in the kilohertz range. However, at frequencies greater than 1 kHz shear waves are rapidly attenuated in soft tissues. In this study μMRE, with geometric focusing, was used to overcome the rapid wave attenuation at high frequencies, enabling the measurement of the shear modulus of tissue-engineered cartilage. This methodology was first tested at a frequency of 5 kHz using a model system composed of alginate beads embedded in agarose, and then applied to evaluate extracellular matrix development in a chondrocyte pellet over a 3-week culture period. The shear stiffness in the pellet was found to increase over time (from 6.4 to 16.4 kPa), and the increase was correlated with both the proteoglycan content and the collagen content of the chondrocyte pellets (R2=0.776 and 0.724, respectively). Our study demonstrates that μMRE when performed with geometric focusing can be used to calculate and map the shear properties within tissue-engineered cartilage during its development. PMID:24266395

  9. Local Chemical Stimulation of Neurons with the Fluidic Force Microscope (FluidFM).

    Science.gov (United States)

    Aebersold, Mathias J; Dermutz, Harald; Demkó, László; Cogollo, José F Saenz; Lin, Shiang-Chi; Burchert, Conrad; Schneider, Moritz; Ling, Doris; Forró, Csaba; Han, Hana; Zambelli, Tomaso; Vörös, János

    2017-10-10

    Physiological communication between neurons is dependent on the exchange of neurotransmitters at the synapses. Although this chemical signal transmission targets specific receptors and allows for subtle adaptation of the action potential, in vitro neuroscience typically relies on electrical currents and potentials to stimulate neurons. The electric stimulus is unspecific and the confinement of the stimuli within the media is technically difficult to control and introduces large artifacts in electric recordings of the activity. Here, we present a local chemical stimulation platform that resembles in vivo physiological conditions and can be used to target specific receptors of synapses. Neurotransmitters were dispensed using the force-controlled fluidic force microscope (FluidFM) nanopipette, which provides exact positioning and precise liquid delivery. We show that controlled release of the excitatory neurotransmitter glutamate induces spiking activity in primary rat hippocampal neurons, as measured by concurrent electrical and optical recordings using a microelectrode array and a calcium-sensitive dye, respectively. Furthermore, we characterized the glutamate dose response of neurons by applying stimulation pulses of glutamate with concentrations from 0 to 0.5 mm. This new stimulation approach, which combines FluidFM for gentle and precise positioning with a microelectrode array read-out, makes it possible to modulate the activity of individual neurons chemically and simultaneously record their induced activity across the entire neuronal network. The presented platform not only offers a more physiological alternative compared with electrical stimulation, but also provides the possibility to study the effects of the local application of neuromodulators and other drugs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. A high-pressure atomic force microscope for imaging in supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Lea, A. S.; Higgins, S. R.; Knauss, K. G.; Rosso, K. M.

    2011-01-01

    A high-pressure atomic force microscope(AFM) that enables in situ, atomic scale measurements of topography of solid surfaces in contact with supercritical CO2 (scCO2) fluids has been developed. This apparatus overcomes the pressure limitations of the hydrothermal AFM and is designed to handle pressures up to 100 atm at temperatures up to ~350 K. A standard optically-based cantilever deflection detection system was chosen. When imaging in compressible supercritical fluids such as scCO2, precise control of pressure and temperature in the fluid cell is the primary technical challenge. Noise levels and imaging resolution depend on minimization of fluid density fluctuations that change the fluidrefractive index and hence the laser path. We demonstrate with our apparatus in situ atomic scale imaging of a calcite (CaCO3) mineral surface in scCO2; both single, monatomic steps and dynamic processes occurring on the (101¯4) surface are presented. Finally, this new AFM provides unprecedented in situ access to interfacial phenomena at solid–fluid interfaces under pressure.

  11. Tip-jump response of an amplitude-modulated Atomic Force Microscope.

    Science.gov (United States)

    Shih, Po-Jen

    2012-01-01

    The dynamic behaviors of an Atomic Force Microscope are of interest, and variously unpredictable phenomena are experimentally measured. In practical measurements, researchers have proposed many methods for avoiding these uncertainties. However, causes of these phenomena are still hard to demonstrate in simulation. To demonstrate these phenomena, this paper claims the tip-jump motion is a predictable process, and the jumping kinetic energy results in different nonlinear phenomena. It emphasizes the variation in the eigenvalues of an AFM with tip-sample distance. This requirement ensures the phase transformations from one associated with the oscillation mode to one associated with the tip-jump/sample-contact mode. Also, multi-modal analysis was utilized to ensure the modal transformation in varying tip-sample distances. In the presented model, oscillations with various tip-sample distances and with various excitation frequencies and amplitudes were compared. The results reveal that the tip-jump motion separates the oscillation orbit into two regions, and the jumping kinetic energy, comparing with the superficial potential energy, leads the oscillation to be bistable or intermittent. The sample-contact condition associates to bifurcation and chaos. Additionally, the jumping is a strong motion that occurs before the tip-sample contacts, and this motion signal can replace the sample-contact-signal to avoid destroying the sample.

  12. Tip-Jump Response of an Amplitude-Modulated Atomic Force Microscope

    Directory of Open Access Journals (Sweden)

    Po-Jen Shih

    2012-05-01

    Full Text Available The dynamic behaviors of an Atomic Force Microscope are of interest, and variously unpredictable phenomena are experimentally measured. In practical measurements, researchers have proposed many methods for avoiding these uncertainties. However, causes of these phenomena are still hard to demonstrate in simulation. To demonstrate these phenomena, this paper claims the tip-jump motion is a predictable process, and the jumping kinetic energy results in different nonlinear phenomena. It emphasizes the variation in the eigenvalues of an AFM with tip-sample distance. This requirement ensures the phase transformations from one associated with the oscillation mode to one associated with the tip-jump/sample-contact mode. Also, multi-modal analysis was utilized to ensure the modal transformation in varying tip-sample distances. In the presented model, oscillations with various tip-sample distances and with various excitation frequencies and amplitudes were compared. The results reveal that the tip-jump motion separates the oscillation orbit into two regions, and the jumping kinetic energy, comparing with the superficial potential energy, leads the oscillation to be bistable or intermittent. The sample-contact condition associates to bifurcation and chaos. Additionally, the jumping is a strong motion that occurrs before the tip-sample contacts, and this motion signal can replace the sample-contact-signal to avoid destroying the sample.

  13. The asymmetrical structure of Golgi apparatus membranes revealed by in situ atomic force microscope.

    Science.gov (United States)

    Xu, Haijiao; Su, Weiheng; Cai, Mingjun; Jiang, Junguang; Zeng, Xianlu; Wang, Hongda

    2013-01-01

    The Golgi apparatus has attracted intense attentions due to its fascinating morphology and vital role as the pivot of cellular secretory pathway since its discovery. However, its complex structure at the molecular level remains elusive due to limited approaches. In this study, the structure of Golgi apparatus, including the Golgi stack, cisternal structure, relevant tubules and vesicles, were directly visualized by high-resolution atomic force microscope. We imaged both sides of Golgi apparatus membranes and revealed that the outer leaflet of Golgi membranes is relatively smooth while the inner membrane leaflet is rough and covered by dense proteins. With the treatment of methyl-β-cyclodextrin and Triton X-100, we confirmed the existence of lipid rafts in Golgi apparatus membrane, which are mostly in the size of 20 nm -200 nm and appear irregular in shape. Our results may be of significance to reveal the structure-function relationship of the Golgi complex and pave the way for visualizing the endomembrane system in mammalian cells at the molecular level.

  14. The asymmetrical structure of Golgi apparatus membranes revealed by in situ atomic force microscope.

    Directory of Open Access Journals (Sweden)

    Haijiao Xu

    Full Text Available The Golgi apparatus has attracted intense attentions due to its fascinating morphology and vital role as the pivot of cellular secretory pathway since its discovery. However, its complex structure at the molecular level remains elusive due to limited approaches. In this study, the structure of Golgi apparatus, including the Golgi stack, cisternal structure, relevant tubules and vesicles, were directly visualized by high-resolution atomic force microscope. We imaged both sides of Golgi apparatus membranes and revealed that the outer leaflet of Golgi membranes is relatively smooth while the inner membrane leaflet is rough and covered by dense proteins. With the treatment of methyl-β-cyclodextrin and Triton X-100, we confirmed the existence of lipid rafts in Golgi apparatus membrane, which are mostly in the size of 20 nm -200 nm and appear irregular in shape. Our results may be of significance to reveal the structure-function relationship of the Golgi complex and pave the way for visualizing the endomembrane system in mammalian cells at the molecular level.

  15. In Situ Roughness Measurements for the Solar Cell Industry Using an Atomic Force Microscope

    Directory of Open Access Journals (Sweden)

    Higinio González-Jorge

    2010-04-01

    Full Text Available Areal roughness parameters always need to be under control in the thin film solar cell industry because of their close relationship with the electrical efficiency of the cells. In this work, these parameters are evaluated for measurements carried out in a typical fabrication area for this industry. Measurements are made using a portable atomic force microscope on the CNC diamond cutting machine where an initial sample of transparent conductive oxide is cut into four pieces. The method is validated by making a comparison between the parameters obtained in this process and in the laboratory under optimal conditions. Areal roughness parameters and Fourier Spectral Analysis of the data show good compatibility and open the possibility to use this type of measurement instrument to perform in situ quality control. This procedure gives a sample for evaluation without destroying any of the transparent conductive oxide; in this way 100% of the production can be tested, so improving the measurement time and rate of production.

  16. AN INTELLIGENT NEURO-FUZZY TERMINAL SLIDING MODE CONTROL METHOD WITH APPLICATION TO ATOMIC FORCE MICROSCOPE

    Directory of Open Access Journals (Sweden)

    Seied Yasser Nikoo

    2016-11-01

    Full Text Available In this paper, a neuro-fuzzy fast terminal sliding mode control method is proposed for controlling a class of nonlinear systems with bounded uncertainties and disturbances. In this method, a nonlinear terminal sliding surface is firstly designed. Then, this sliding surface is considered as input for an adaptive neuro-fuzzy inference system which is the main controller. A proportinal-integral-derivative controller is also used to asist the neuro-fuzzy controller in order to improve the performance of the system at the begining stage of control operation. In addition, bee algorithm is used in this paper to update the weights of neuro-fuzzy system as well as the parameters of the proportinal-integral-derivative controller. The proposed control scheme is simulated for vibration control in a model of atomic force microscope system and the results are compared with conventional sliding mode controllers. The simulation results show that the chattering effect in the proposed controller is decreased in comparison with the sliding mode and the terminal sliding mode controllers. Also, the method provides the advantages of fast convergence and low model dependency compared to the conventional methods.

  17. Fabrication of periodic nanostructures using dynamic plowing lithography with the tip of an atomic force microscope

    Science.gov (United States)

    He, Yang; Yan, Yongda; Geng, Yanquan; Brousseau, Emmanuel

    2018-01-01

    The fabrication of periodic nanostructures with a fine control of their dimensions is performed on poly(methyl methacrylate) (PMMA) thin films using an atomic force microscope technique called dynamic plowing lithography (DPL). Different scratching directions are investigated first when generating single grooves with DPL. In particular, the depth, the width and the periodicity of the machined grooves as well the height of the pile-up, formed on the side of the grooves, are assessed. It was found that these features are not significantly affected by the scratching direction, except when processing took place in a direction away from the cantilever probe and parallel to its main axis. For a given scratching direction, arrays of regular grooves are then obtained by controlling the feed, i.e. the distance between two machining lines. A scan-scratch tip trace is also used to reduce processing time and tip wear. However, irregular patterns are created when combining two layers oriented at different angles and where each layer defines an array of grooves. Thus, a ;combination writing; method was implemented to fabricate arrays of grooves with a well-defined wavelength of 30 nm, which was twice the feed value utilized. Checkerboard, diamond-shaped, and hexagonal nanodots were also fabricated. These were obtained by using the combination writing method and by varying the orientation and the number of layers. The density of the nanodots achieved could be as high as 1.9 × 109 nanodots per mm2.

  18. Robust nanobubble and nanodroplet segmentation in atomic force microscope images using the spherical Hough transform

    Directory of Open Access Journals (Sweden)

    Yuliang Wang

    2017-12-01

    Full Text Available Interfacial nanobubbles (NBs and nanodroplets (NDs have been attracting increasing attention due to their potential for numerous applications. As a result, the automated segmentation and morphological characterization of NBs and NDs in atomic force microscope (AFM images is highly awaited. The current segmentation methods suffer from the uneven background in AFM images due to thermal drift and hysteresis of AFM scanners. In this study, a two-step approach was proposed to segment NBs and NDs in AFM images in an automated manner. The spherical Hough transform (SHT and a boundary optimization operation were combined to achieve robust segmentation. The SHT was first used to preliminarily detect NBs and NDs. After that, the so-called contour expansion operation was applied to achieve optimized boundaries. The principle and the detailed procedure of the proposed method were presented, followed by the demonstration of the automated segmentation and morphological characterization. The result shows that the proposed method gives an improved segmentation result compared with the thresholding and circle Hough transform method. Moreover, the proposed method shows strong robustness of segmentation in AFM images with an uneven background.

  19. Robust nanobubble and nanodroplet segmentation in atomic force microscope images using the spherical Hough transform.

    Science.gov (United States)

    Wang, Yuliang; Lu, Tongda; Li, Xiaolai; Ren, Shuai; Bi, Shusheng

    2017-01-01

    Interfacial nanobubbles (NBs) and nanodroplets (NDs) have been attracting increasing attention due to their potential for numerous applications. As a result, the automated segmentation and morphological characterization of NBs and NDs in atomic force microscope (AFM) images is highly awaited. The current segmentation methods suffer from the uneven background in AFM images due to thermal drift and hysteresis of AFM scanners. In this study, a two-step approach was proposed to segment NBs and NDs in AFM images in an automated manner. The spherical Hough transform (SHT) and a boundary optimization operation were combined to achieve robust segmentation. The SHT was first used to preliminarily detect NBs and NDs. After that, the so-called contour expansion operation was applied to achieve optimized boundaries. The principle and the detailed procedure of the proposed method were presented, followed by the demonstration of the automated segmentation and morphological characterization. The result shows that the proposed method gives an improved segmentation result compared with the thresholding and circle Hough transform method. Moreover, the proposed method shows strong robustness of segmentation in AFM images with an uneven background.

  20. Reversible mechano-electrochemical writing of metallic nanostructures with the tip of an atomic force microscope

    Directory of Open Access Journals (Sweden)

    Christian Obermair

    2012-12-01

    Full Text Available We recently introduced a method that allows the controlled deposition of nanoscale metallic patterns at defined locations using the tip of an atomic force microscope (AFM as a “mechano-electrochemical pen”, locally activating a passivated substrate surface for site-selective electrochemical deposition. Here, we demonstrate the reversibility of this process and study the long-term stability of the resulting metallic structures. The remarkable stability for more than 1.5 years under ambient air without any observable changes can be attributed to self-passivation. After AFM-activated electrochemical deposition of copper nanostructures on a polycrystalline gold film and subsequent AFM imaging, the copper nanostructures could be dissolved by reversing the electrochemical potential. Subsequent AFM-tip-activated deposition of different copper nanostructures at the same location where the previous structures were deleted, shows that there is no observable memory effect, i.e., no effect of the previous writing process on the subsequent writing process. Thus, the four processes required for reversible information storage, “write”, “read”, “delete” and “re-write”, were successfully demonstrated on the nanometer scale.

  1. Detection of erythrocytes influenced by aging and type 2 diabetes using atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Hua; Xing, Xiaobo [Chemistry Department, Jinan University, Guangzhou 510632 (China); Zhao, Hongxia [Chemistry Department, Jinan University, Guangzhou 510632 (China); Faculty of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510090 (China); Chen, Yong [Institute for Advanced Study, Nanchang University, Nanchang, Jiangxi 330031 (China); Huang, Xun [Chemistry Department, Jinan University, Guangzhou 510632 (China); Ma, Shuyuan [Chemistry Department, Jinan University, Guangzhou 510632 (China); The First Affiliated Hospital, Jinan University, Guangzhou 510632 (China); Ye, Hongyan [Chemistry Department, Jinan University, Guangzhou 510632 (China); Cai, Jiye, E-mail: tjycai@jnu.edu.cn [Chemistry Department, Jinan University, Guangzhou 510632 (China)

    2010-01-22

    The pathophysiological changes of erythrocytes are detected at the molecular scale, which is important to reveal the onset of diseases. Type 2 diabetes is an age-related metabolic disorder with high prevalence in elderly (or old) people. Up to now, there are no treatments to cure diabetes. Therefore, early detection and the ability to monitor the progression of type 2 diabetes are very important for developing effective therapies. Type 2 diabetes is associated with high blood glucose in the context of insulin resistance and relative insulin deficiency. These abnormalities may disturb the architecture and functions of erythrocytes at molecular scale. In this study, the aging- and diabetes-induced changes in morphological and biomechanical properties of erythrocytes are clearly characterized at nanometer scale using atomic force microscope (AFM). The structural information and mechanical properties of the cell surface membranes of erythrocytes are very important indicators for determining the healthy, diseased or aging status. So, AFM may potentially be developed into a powerful tool in diagnosing diseases.

  2. Nanoimaging and ultra structure of Entamoeba histolytica and its pseudopods by using atomic force microscope

    Science.gov (United States)

    Joshi, Narahari V.; Medina, Honorio; Urdaneta, H.; Barboza, J.

    2000-04-01

    Nan-imaging of Entamoeba histolytica was carried out by using Atomic Force Microscope (AFM). The structure of the nucleus, endoplasm and ectoplasm were studied separately. The diameter of the nucleus in living E. histolytica was found to be of the order of 10 micrometers which is slightly higher than the earlier reported value. The presence of karysome was detected in the nucleus. Well-organized patterns of chromatoid bodies located within the endoplasm, were detected and their repetitive patterns were examined. The organized structure was also extended within the ectoplasm. The dimensions and form of the organization suggest that chromatic bodies are constituted with ribosomes ordered in the form of folded sheet. Such structures were found to be absent in non-living E. histolytica. AFM images were also captured just in the act when ameba was extending its pseudopods. Alteration in the ultrastructure caused during the process of extension was viewed. Well marked canals of width 694.05 nm. And height 211.05 nm are clearly perceptible towards the direction of the pseudopods. 3D images are presented to appreciate the height variation, which can not be achieved by conventional well-established techniques such as electron microscopy.

  3. Characterization of the photocurrents generated by the laser of atomic force microscopes

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Yanfeng; Hui, Fei; Shi, Yuanyuan; Lanza, Mario, E-mail: mlanza@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nanoscience and Technology, Soochow University, 199 Ren-Ai Road, Suzhou 215123 (China); Iglesias, Vanessa [International Iberian Nanotechnology Laboratory, 4715-330 Braga (Portugal); Lewis, David [Nanonics Imaging, Har Hotzvim, Jerusalem 91487 (Israel); Niu, Jiebin; Long, Shibing; Liu, Ming [Laboratory of Nanofabrication and Novel Device Integration, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029 (China); Hofer, Alexander; Frammelsberger, Werner; Benstetter, Guenther [Deggendorf Institute of Technology, Edlmairstr. 6+8, 94469 Deggendorf (Germany); Scheuermann, Andrew; McIntyre, Paul C. [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

    2016-08-15

    The conductive atomic force microscope (CAFM) has become an essential tool for the nanoscale electronic characterization of many materials and devices. When studying photoactive samples, the laser used by the CAFM to detect the deflection of the cantilever can generate photocurrents that perturb the current signals collected, leading to unreliable characterization. In metal-coated semiconductor samples, this problem is further aggravated, and large currents above the nanometer range can be observed even without the application of any bias. Here we present the first characterization of the photocurrents introduced by the laser of the CAFM, and we quantify the amount of light arriving to the surface of the sample. The mechanisms for current collection when placing the CAFM tip on metal-coated photoactive samples are also analyzed in-depth. Finally, we successfully avoided the laser-induced perturbations using a two pass technique: the first scan collects the topography (laser ON) and the second collects the current (laser OFF). We also demonstrate that CAFMs without a laser (using a tuning fork for detecting the deflection of the tip) do not have this problem.

  4. Microscopic properties of degradation-free capped GdN thin films studied by electron spin resonance

    Energy Technology Data Exchange (ETDEWEB)

    Shimokawa, Tokuro [Center for Collaborative Research and Technology Development, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo 657-8501 (Japan); Fukuoka, Yohei [Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo 657-8501 (Japan); Fujisawa, Masashi [Research Center for Low Temperature Physics, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo 152-8551 (Japan); Zhang, Weimin; Okubo, Susumu; Ohta, Hitoshi, E-mail: hohta@kobe-u.ac.jp [Molecular Photoscience Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo 657-8501 (Japan); Sakurai, Takahiro [Center for Supports to Research and Education Activities, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo 657-8501 (Japan); Vidyasagar, Reddithota; Yoshitomi, Hiroaki; Kitayama, Shinya; Kita, Takashi [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Kobe 657-8501 (Japan)

    2015-01-28

    The microscopic magnetic properties of high-quality GdN thin films have been investigated by electron spin resonance (ESR) and ferromagnetic resonance (FMR) measurements. Detailed temperature dependence ESR measurements have shown the existence of two ferromagnetic components at lower temperatures, which was not clear from the previous magnetization measurements. The temperature, where the resonance shift occurs for the major ferromagnetic component, seems to be consistent with the Curie temperature obtained from the previous magnetization measurement. On the other hand, the divergence of line width is observed around 57 K for the minor ferromagnetic component. The magnetic anisotropies of GdN thin films have been obtained by the analysis of FMR angular dependence observed at 4.2 K. Combining the X-ray diffraction results, the correlation between the magnetic anisotropies and the lattice constants is discussed.

  5. Non-monotonic resonance in a spatially forced Lengyel-Epstein model

    Energy Technology Data Exchange (ETDEWEB)

    Haim, Lev [Physics Department, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Department of Oncology, Soroka University Medical Center, Beer-Sheva 84101 (Israel); Hagberg, Aric [Center for Nonlinear Studies, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Meron, Ehud [Physics Department, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Department of Solar Energy and Environmental Physics, BIDR, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion 84990 (Israel)

    2015-06-15

    We study resonant spatially periodic solutions of the Lengyel-Epstein model modified to describe the chlorine dioxide-iodine-malonic acid reaction under spatially periodic illumination. Using multiple-scale analysis and numerical simulations, we obtain the stability ranges of 2:1 resonant solutions, i.e., solutions with wavenumbers that are exactly half of the forcing wavenumber. We show that the width of resonant wavenumber response is a non-monotonic function of the forcing strength, and diminishes to zero at sufficiently strong forcing. We further show that strong forcing may result in a π/2 phase shift of the resonant solutions, and argue that the nonequilibrium Ising-Bloch front bifurcation can be reversed. We attribute these behaviors to an inherent property of forcing by periodic illumination, namely, the increase of the mean spatial illumination as the forcing amplitude is increased.

  6. Description of the giant monopole resonance in the even-A Sn112-124 isotopes within a microscopic model including quasiparticle-phonon coupling

    Science.gov (United States)

    Tselyaev, V.; Speth, J.; Krewald, S.; Litvinova, E.; Kamerdzhiev, S.; Lyutorovich, N.; Avdeenkov, A.; Grümmer, F.

    2009-03-01

    We have calculated the strength distributions of the isoscalar giant monopole resonance (ISGMR) in the even-A tin isotopes (A=112-124) that were recently measured in inelastic α scattering. The calculations were performed within two microscopic models: the quasiparticle random phase approximation (QRPA) and the quasiparticle time blocking approximation (QTBA), which is an extension of the QRPA including quasiparticle-phonon coupling. We used a self-consistent calculational scheme based on the Hartree-Fock+Bardeen-Cooper-Schrieffer approximation. Within the RPA the self-consistency is full. The single-particle continuum is also exactly included at the RPA level. The self-consistent mean field and the effective interaction are derived from the Skyrme energy functional. In the calculations, two Skyrme force parametrizations were used: T5 with a comparatively low value of the incompressibility modulus of infinite nuclear matter (K∞=202 MeV) and T6 with K∞=236 MeV. The T5 parametrization gives theoretical results for tin isotopes in good agreement with the experimental data including the resonance widths. The results of the ISGMR calculations in Zr90, Sm144, and Pb208 performed with these Skyrme forces are discussed and compared with the experiment.

  7. Fano resonances in the optical scattering force upon a high-index dielectric nanoparticle

    Science.gov (United States)

    Duan, Xiao-Yong; Wang, Zhi-Guo

    2017-11-01

    Effects of Fano resonances on optical scattering force upon a high-index dielectric nanoparticle radiated by a plane wave are theoretically investigated. The results demonstrate that five different types of Fano resonances appear in the force and are expressed in a unified way. The magnetic (electric) -based cascades of Fano resonances dominate the peaks of the force. The magnetic (electric) -based conventional Fano resonances and the unconventional Fano resonances suppress the peaks of the force for particular large nanoparticles. All types of Fano resonances together cause broad dips of the force and even a near-zero force effect at particular radii. Finally, by investigating the effects of positive and negative indexes, loss, and gain of the particle on the force, it is shown that negative force arises only as the appropriate gain is introduced in the particle. Our results are important for not only deep understanding of electromagnetic interactions in the optical force but also stable optical manipulation of the dielectric nanoparticle.

  8. Fabrication of large scale nanostructures based on a modified atomic force microscope nanomechanical machining system.

    Science.gov (United States)

    Hu, Z J; Yan, Y D; Zhao, X S; Gao, D W; Wei, Y Y; Wang, J H

    2011-12-01

    The atomic force microscope (AFM) tip-based nanomechanical machining has been demonstrated to be a powerful tool for fabricating complex 2D∕3D nanostructures. But the machining scale is very small, which holds back this technique severely. How to enlarge the machining scale is always a major concern for the researches. In the present study, a modified AFM tip-based nanomechanical machining system is established through combination of a high precision X-Y stage with the moving range of 100 mm × 100 mm and a commercial AFM in order to enlarge the machining scale. It is found that the tracing property of the AFM system is feasible for large scale machining by controlling the constant normal load. Effects of the machining parameters including the machining direction and the tip geometry on the uniform machined depth with a large scale are evaluated. Consequently, a new tip trace and an increasing load scheme are presented to achieve a uniform machined depth. Finally, a polymer nanoline array with the dimensions of 1 mm × 0.7 mm, the line density of 1000 lines/mm and the average machined depth of 150 nm, and a 20 × 20 polymer square holes array with the scale of 380 μm × 380 μm and the average machined depth of 250 nm are machined successfully. The uniform of the machined depths for all the nanostructures is acceptable. Therefore, it is verified that the AFM tip-based nanomechanical machining method can be used to machine millimeter scale nanostructures.

  9. Evaluation of carbon nanotube probes in critical dimension atomic force microscopes

    Science.gov (United States)

    Choi, Jinho; Park, Byong Chon; Ahn, Sang Jung; Kim, Dal-Hyun; Lyou, Joon; Dixson, Ronald G.; Orji, Ndubuisi G.; Fu, Joseph; Vorburger, Theodore V.

    2016-07-01

    The decreasing size of semiconductor features and the increasing structural complexity of advanced devices have placed continuously greater demands on manufacturing metrology, arising both from the measurement challenges of smaller feature sizes and the growing requirement to characterize structures in more than just a single critical dimension. For scanning electron microscopy, this has resulted in increasing sophistication of imaging models. For critical dimension atomic force microscopes (CD-AFMs), this has resulted in the need for smaller and more complex tips. Carbon nanotube (CNT) tips have thus been the focus of much interest and effort by a number of researchers. However, there have been significant issues surrounding both the manufacture and use of CNT tips. Specifically, the growth or attachment of CNTs to AFM cantilevers has been a challenge to the fabrication of CNT tips, and the flexibility and resultant bending artifacts have presented challenges to using CNT tips. The Korea Research Institute for Standards and Science (KRISS) has invested considerable effort in the controlled fabrication of CNT tips and is collaborating with the National Institute of Standards and Technology on the application of CNT tips for CD-AFM. Progress by KRISS on the precise control of CNT orientation, length, and end modification, using manipulation and focused ion beam processes, has allowed us to implement ball-capped CNT tips and bent CNT tips for CD-AFM. Using two different generations of CD-AFM instruments, we have evaluated these tip types by imaging a line/space grating and a programmed line edge roughness specimen. We concluded that these CNTs are capable of scanning the profiles of these structures, including re-entrant sidewalls, but there remain important challenges to address. These challenges include tighter control of tip geometry and careful optimization of scan parameters and algorithms for using CNT tips.

  10. Novel atomic force microscope cantilevers and piezoresistance of carbon nanotubes and germanium nanowires

    Science.gov (United States)

    Grow, Randal James

    2005-11-01

    There has been great interest in recent years in nanometer-scale materials and tools for fabricating and characterizing them. One such tool is the atomic force microscope (AFM), which has developed rapidly since its invention in 1986. Imaging soft or fragile samples with AFM requires low-spring-constant cantilevers to minimize the force on the sample. Silicon nitride is well suited to making such soft cantilevers, but it is not ideal for making sharp tips. We combined a silicon nitride cantilever with a sharp silicon tip to achieve a hybrid with both a low spring constant and a sharp tip. Carbon nanotubes have received great attention for their remarkable mechanical and electrical properties. Their electromechanical properties are also interesting, as a few groups have determined by deforming suspended nanotubes. Their change in resistance under strain is stronger than that of silicon, which is commonly used in mechanical sensors. However, the fragility of suspended tubes makes them impractical for mass-produced sensors. Tubes on surfaces are more robust. We fabricated micromachined pressure sensors using a thin silicon nitride membrane with metal-contacted carbon nanotubes on the surface. Deforming the membrane with gas pressure stretched the nanotube, and we measured the resistance changes. They were stronger than those of suspended nanotubes, probably because of local deformations in the nanotube caused by interaction with the surface. Nanowires of semiconductors such as silicon and germanium have also evoked much interest for electronics and optics applications. The piezoresistive effect in nanowires should also be larger than that of the bulk material, which could be useful for increasing the sensitivity of mechanical sensors or for enhancing the performance of nanowire transistors. We have fabricated pressure sensors with germanium nanowires as the sensing elements, and we have found the piezoresistance to be much stronger than in the bulk. We understand this

  11. [Connection of magnetic antisense probe with SK-Br-3 oncocyte mRNA nucleotide detected by high resolution atomic force microscope].

    Science.gov (United States)

    Tan, Shude; Ouyang, Yu; Li, Xinyou; Wen, Ming; Li, Shaolin

    2011-06-01

    The present paper is aimed to detect superparamagnetic iron oxide labeled c-erbB2 oncogene antisense oligonucleotide probe (magnetic antisense probe) connected with SK-Br-3 oncocyte mRNA nucleotide by high resolution atomic force microscope (AFM). We transfected SK-Br-3 oncocyte with magnetic antisense probe, then observed the cells by AFM with high resolution and detected protein expression and magnetic resonance imagine (MRI). The high resolution AFM clearly showed the connection of the oligonucleotide remote end of magnetic antisense probe with the mRNA nucleotide of oncocyte. The expression of e-erbB2 protein in SK-Br3 cells were highly inhibited by using magnetic antisense probe. We then obtained the lowest signal to noise ratio (SNR) of SK-Br-3 oncocyte transfected with magnetic antisense probe by MRI (Pmagnetic antisense probe and SK-Br-3 mRNA of tumor cell nuclear.

  12. Development of a shear-force scanning near-field cathodoluminescence microscope for characterization of nanostructures' optical properties.

    Science.gov (United States)

    Bercu, N B; Troyon, M; Molinari, M

    2016-09-01

    An original scanning near-field cathodoluminescence microscope for nanostructure characterization has been developed and successfully tested. By using a bimorph piezoelectric stack both as actuator and detector, the developed setup constitutes a real improvement compared to previously reported SEM-based solutions. The technique combines a scanning probe and a scanning electron microscope in order to simultaneously offer near-field cathodoluminescence and topographic images of the sample. Share-force topography and cathodoluminescence measurements on GaN, SiC and ZnO nanostructures using the developed setup are presented showing a nanometric resolution in both topography and cathodoluminescence images with increased sensitivity compared to classical luminescence techniques. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

  13. Resonance interaction between Bays and Harbors forced by tsunamis

    Science.gov (United States)

    Vela, Jordi; Pérez, Begoña.; González, Mauricio; Otero, Luis; Olabarrieta, Maitane; Canals, Miquel

    2010-05-01

    The tsunami induced by the 21 May 2003 Boumerdès-Zemmouri (Algeria) earthquake (Mw=6.9) did not generated important inundations damages or fatalities in the western Mediterranean area. However, damages and economic losses were reported in some harbors, generated by important sea level disturbances. Noticeable impacts were noted (broken mooring lines, sunken boats, displaced moorings, etc.) in some harbours in the Balearic Islands (Palma de Majorca, Ibiza and San Antoni) and also along the French border (La Figueirette and Mouré-Rouge harbours). Various authors have attempted to simulate this event finding discrepancies between the tsunami arrival time and amplitudes of waves on the tide gauges and results with numerical models. The models underestimate the amplitude of the tsunami. In some cases the underestimations have been associated to numerical limitations due to the lack of a high-resolution bathymetry and poor harbor geometry definition. Other cases, associated to a non appropriate seismic source characterization. Finally, some authors point out the occurrence of one or several submarine landslides triggered by the earthquake simultaneously with the seafloor vertical displacement, which have not been included in the numerical simulations. For a better knowledge of the response of a harbour interacting with a bay forced by a tsunami, a numerical study has been carried out for Palma Bay and Palma de Majorca Harbour. The transference of energy of the tsunami from the generation area to the continental shelf, the bay and the harbour has been studied for the Algerian tsunami (21 May 2003) and compared with the natural oscillation modes of the bay and the harbour water bodies. Furthermore, a sensibility analysis regarding the influence of the grid size of the harbour and bay bathymetries was also performed to understand the discrepancies between simulations and observations. The 2003 Zemmouri tsunami measured by the tidal gauge of Palma habour showed energy

  14. Analyzing the Effect of Capillary Force on Vibrational Performance of the Cantilever of an Atomic Force Microscope in Tapping Mode with Double Piezoelectric Layers in an Air Environment.

    Science.gov (United States)

    Nahavandi, Amir; Korayem, Moharam Habibnejad

    2015-10-01

    The aim of this paper is to determine the effects of forces exerted on the cantilever probe tip of an atomic force microscope (AFM). These forces vary according to the separation distance between the probe tip and the surface of the sample being examined. Hence, at a distance away from the surface (farther than d(on)), these forces have an attractive nature and are of Van der Waals type, and when the probe tip is situated in the range of a₀≤ d(ts) ≤ d(on), the capillary force is added to the Van der Waals force. At a distance of d(ts) ≤ a₀, the Van der Waals and capillary forces remain constant at intermolecular distances, and the contact repulsive force repels the probe tip from the surface of sample. The capillary force emerges due to the contact of thin water films with a thickness of h(c) which have accumulated on the sample and probe. Under environmental conditions a layer of water or hydrocarbon often forms between the probe tip and sample. The capillary meniscus can grow until the rate of evaporation equals the rate of condensation. For each of the above forces, different models are presented. The smoothness or roughness of the surfaces and the geometry of the cantilever tip have a significant effect on the modeling of forces applied on the probe tip. Van der Waals and the repulsive forces are considered to be the same in all the simulations, and only the capillary force is altered in order to evaluate the role of this force in the AFM-based modeling. Therefore, in view of the remarkable advantages of the piezoelectric microcantilever and also the extensive applications of the tapping mode, we investigate vibrational motion of the piezoelectric microcantilever in the tapping mode. The cantilever mentioned is entirely covered by two piezoelectric layers that carry out both the actuation of the probe tip and the measuringof its position.

  15. Clamping instability and van der Waals forces in carbon nanotube mechanical resonators.

    Science.gov (United States)

    Aykol, Mehmet; Hou, Bingya; Dhall, Rohan; Chang, Shun-Wen; Branham, William; Qiu, Jing; Cronin, Stephen B

    2014-05-14

    We investigate the role of weak clamping forces, typically assumed to be infinite, in carbon nanotube mechanical resonators. Due to these forces, we observe a hysteretic clamping and unclamping of the nanotube device that results in a discrete drop in the mechanical resonance frequency on the order of 5-20 MHz, when the temperature is cycled between 340 and 375 K. This instability in the resonant frequency results from the nanotube unpinning from the electrode/trench sidewall where it is bound weakly by van der Waals forces. Interestingly, this unpinning does not affect the Q-factor of the resonance, since the clamping is still governed by van der Waals forces above and below the unpinning. For a 1 μm device, the drop observed in resonance frequency corresponds to a change in nanotube length of approximately 50-65 nm. On the basis of these findings, we introduce a new model, which includes a finite tension around zero gate voltage due to van der Waals forces and shows better agreement with the experimental data than the perfect clamping model. From the gate dependence of the mechanical resonance frequency, we extract the van der Waals clamping force to be 1.8 pN. The mechanical resonance frequency exhibits a striking temperature dependence below 200 K attributed to a temperature-dependent slack arising from the competition between the van der Waals force and the thermal fluctuations in the suspended nanotube.

  16. Next force sensing technology for robots: multi-axis resonant sensors

    Science.gov (United States)

    Castano-Cano, Davinson; Grossard, Mathieu; Hubert, Arnaud

    2016-05-01

    The aim of this paper is to present a novel resonant multi-axis force sensor with applications in robotics. A resonant force sensor is characterized by the use of a frequency output signal to estimate the applied forces, instead of using its amplitude as it is often the case for the other existing technologies used in robotics. The advantages of resonant force sensing for robotics are discussed, especially for the safety requirements in the collaborative field. We extend our analysis to show the main similarities and differences between more classical sensors (based on strain gages for instance) and resonant ones, with a focus on their design. More specifically, we detail the way the design of the sensitive element, which essentially transduces the applied forces into frequencies, plays a major role on its performances.

  17. In-situ scanning electron microscopy and atomic force microscopy Young's modulus determination of indium oxide microrods for micromechanical resonator applications

    Energy Technology Data Exchange (ETDEWEB)

    Bartolomé, Javier; Hidalgo, Pedro; Maestre, David; Cremades, Ana, E-mail: cremades@fis.ucm.es; Piqueras, Javier [Departamento de Física de Materiales, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain)

    2014-04-21

    Electric field induced mechanical resonances of In{sub 2}O{sub 3} microrods are studied by in-situ measurements in the chamber of a scanning electron microscope. Young's moduli of rods with different cross-sectional shapes are calculated from the resonance frequency, and a range of values between 131 and 152 GPa are obtained. A quality factor of 1180–3780 is measured from the amplitude-frequency curves, revealing the suitability of In{sub 2}O{sub 3} microrods as micromechanical resonators. The Young's modulus, E, of one of the rods is also measured from the elastic response in the force-displacement curve recorded in an atomic force microscope. E values obtained by in-situ scanning electron microscopy and by atomic force microscopy are found to differ in about 8%. The results provide data on Young's modulus of In{sub 2}O{sub 3} and confirm the suitability of in-situ scanning electron microscopy mechanical resonance measurements to investigate the elastic behavior of semiconductor microrods.

  18. Electron fluctuation induced resonance broadening in nano electromechanical systems: the origin of shear force in vacuum.

    Science.gov (United States)

    Siria, A; Barois, T; Vilella, K; Perisanu, S; Ayari, A; Guillot, D; Purcell, S T; Poncharal, P

    2012-07-11

    This article presents a study of the poorly understood "shear-force" used in an important class of near-field instruments that use mechanical resonance feedback detection. In the case of a metallic probe near a metallic surface in vacuum, we show that in the 10-60 nm range there is no such a thing as a shear-force in the sense of the nonconservative friction force. Fluctuations of the oscillator resonance frequency, likely induced by local charge variations, could account for the reported effects in the literature without introducing a dissipative force.

  19. Installation of an IR microscope at the nuclear resonance beamline ID18 of ESRF

    Energy Technology Data Exchange (ETDEWEB)

    Rackwitz, Sergej, E-mail: rackwitz@physik.uni-kl.de; Wolny, Juliusz A.; Muffler, Kai [University of Kaiserslautern, Department of Physics (Germany); Krueger, Hans-Joerg; Reh, Sabine; Kelm, Harald [University of Kaiserslautern, Department of Chemistry (Germany); Chumakov, Alexander I. [ESRF (France); Schuenemann, Volker [University of Kaiserslautern, Department of Physics (Germany)

    2012-03-15

    An IR microscope has been installed at the beamline ID18 at the ESRF in Grenoble, France in order to obtain nuclear inelastic scattering (NIS) data and IR spectra simultaneously. This setup combines the advantages of both spectroscopic methods. The applicability of the installed setup to the study of the spin crossover (SCO) phenomenon in polynuclear iron complexes has been shown.

  20. A Magnetic Resonance Force Microscopy Quantum Computer with Tellurium Donors in Silicon

    OpenAIRE

    Berman, G. P.; Doolen, G. D.; Tsifrinovich, V. I.

    2000-01-01

    We propose a magnetic resonance force microscopy (MRFM)-based nuclear spin quantum computer using tellurium impurities in silicon. This approach to quantum computing combines the well-developed silicon technology with expected advances in MRFM.

  1. Large area scanning probe microscope in ultra-high vacuum demonstrated for electrostatic force measurements on high-voltage devices

    Directory of Open Access Journals (Sweden)

    Urs Gysin

    2015-12-01

    Full Text Available Background: The resolution in electrostatic force microscopy (EFM, a descendant of atomic force microscopy (AFM, has reached nanometre dimensions, necessary to investigate integrated circuits in modern electronic devices. However, the characterization of conducting or semiconducting power devices with EFM methods requires an accurate and reliable technique from the nanometre up to the micrometre scale. For high force sensitivity it is indispensable to operate the microscope under high to ultra-high vacuum (UHV conditions to suppress viscous damping of the sensor. Furthermore, UHV environment allows for the analysis of clean surfaces under controlled environmental conditions. Because of these requirements we built a large area scanning probe microscope operating under UHV conditions at room temperature allowing to perform various electrical measurements, such as Kelvin probe force microscopy, scanning capacitance force microscopy, scanning spreading resistance microscopy, and also electrostatic force microscopy at higher harmonics. The instrument incorporates beside a standard beam deflection detection system a closed loop scanner with a scan range of 100 μm in lateral and 25 μm in vertical direction as well as an additional fibre optics. This enables the illumination of the tip–sample interface for optically excited measurements such as local surface photo voltage detection.Results: We present Kelvin probe force microscopy (KPFM measurements before and after sputtering of a copper alloy with chromium grains used as electrical contact surface in ultra-high power switches. In addition, we discuss KPFM measurements on cross sections of cleaved silicon carbide structures: a calibration layer sample and a power rectifier. To demonstrate the benefit of surface photo voltage measurements, we analysed the contact potential difference of a silicon carbide p/n-junction under illumination.

  2. A dark-field microscope for background-free detection of resonance fluorescence from single semiconductor quantum dots operating in a set-and-forget mode

    Energy Technology Data Exchange (ETDEWEB)

    Kuhlmann, Andreas V.; Houel, Julien; Warburton, Richard J. [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Brunner, Daniel [Instituto de Física Interdisciplinar y Sistemas Complejos, IFISC (CSIC-UIB), Campus Universitat Illes Balears, E-07122 Palma de Mallorca (Spain); Ludwig, Arne [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Reuter, Dirk [Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Department Physik, Universität Paderborn, Warburger Strasse 100, D-33098 Paderborn (Germany); Wieck, Andreas D. [Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany)

    2013-07-15

    Optically active quantum dots, for instance self-assembled InGaAs quantum dots, are potentially excellent single photon sources. The fidelity of the single photons is much improved using resonant rather than non-resonant excitation. With resonant excitation, the challenge is to distinguish between resonance fluorescence and scattered laser light. We have met this challenge by creating a polarization-based dark-field microscope to measure the resonance fluorescence from a single quantum dot at low temperature. We achieve a suppression of the scattered laser exceeding a factor of 10{sup 7} and background-free detection of resonance fluorescence. The same optical setup operates over the entire quantum dot emission range (920–980 nm) and also in high magnetic fields. The major development is the outstanding long-term stability: once the dark-field point has been established, the microscope operates for days without alignment. The mechanical and optical designs of the microscope are presented, as well as exemplary resonance fluorescence spectroscopy results on individual quantum dots to underline the microscope's excellent performance.

  3. Atomic force microscopic study of the structure of high-density polyethylene deformed in liquid medium by crazing mechanism.

    Science.gov (United States)

    Bagrov, D V; Yarysheva, A Y; Rukhlya, E G; Yarysheva, L M; Volynskii, A L; Bakeev, N F

    2014-02-01

    A procedure has been developed for the direct atomic force microscopic (AFM) examination of the native structure of high-density polyethylene (HDPE) deformed in an adsorption-active liquid medium (AALM) by the crazing mechanism. The AFM investigation has been carried out in the presence of a liquid medium under conditions preventing deformed films from shrinkage. Deformation of HDPE in AALM has been shown to proceed through the delocalized crazing mechanism and result in the development of a fibrillar-porous structure. The structural parameters of the crazed polymer have been determined. The obtained AFM images demonstrate a nanosized nonuniformity of the deformation and enable one to observe the structural rearrangements that take place in the deformed polymer after removal of the liquid medium and stress relaxation. A structural similarity has been revealed between HDPE deformed in the AALM and hard elastic polymers. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

  4. Toward mechanical manipulations of cell membranes and membrane proteins using an atomic force microscope: an invited review.

    Science.gov (United States)

    Ikai, Atsushi; Afrin, Rehana

    2003-01-01

    Recent advances in the use of the atomic force microscope (AFM) for manipulating cell membranes and membrane proteins are reviewed. Early pioneering work on measurements of the magnitude of the force required to create indentations with defined depth on their surfaces and to separate interacting pairs of avidin-biotin, antigen-antibody, and complementary DNA pairs formed the basis of this field. The method has subsequently been applied to map the presence of cell surface receptors and polysaccharides on live cell membranes by force measurement, with promising results. Attempts to extract phospholipids and proteins from lipid bilayers and live cell surfaces have been reported, providing a new tool for the manipulation of cellular activities and biochemical analysis at the single-cell level. An increasing awareness of the effect of the pulling speed (nm/s or microm/s), or more accurately, the force loading rate (pN/s or nN/s) on the magnitude of the rupture force, has led researchers to construct energy diagrams of rupture events based on the parameters available from such studies. Information on such nature of the interplay of force and loading rate is vital for nanomanipulation of living cells and cell membranes. Some relevant work for membrane manipulation using other methods is also reviewed in relation to AFM-based methodology.

  5. Solution Hardening in Aluminium-Magnesium Alloys : A Nuclear Magnetic Resonance and Transmission Electron Microscopic Study

    NARCIS (Netherlands)

    Schlagowski, U.; Kanert, O.; Hosson, J.Th.M. De; Boom, G.

    1988-01-01

    Pulsed nuclear magnetic resonance techniques as well as transmission electron microscopy have been applied to study dislocation motion in aluminium magnesium alloys (0.2-1.6 at.% Mg). The spin lattice relaxation rate in the rotating frame of 27Al has been been measured at 77 K as a function of

  6. DISLOCATION DYNAMICS IN VANADIUM - A NUCLEAR-MAGNETIC-RESONANCE AND TRANSMISSION ELECTRON-MICROSCOPIC STUDY

    NARCIS (Netherlands)

    CHRISTIAN, A; KANERT, O; DEHOSSON, JTM

    1990-01-01

    Pulsed nuclear magnetic resonance proved to be a complementary new technique for the study of moving dislocations in b.c.c. metals. From the motion induced part of the spin-lattice relaxation rate the mean jump distance of mobile dislocations has been measured in Vanadium as a function of

  7. Stress relaxation and creep experiments with the atomic force microscope: a unified method to calculate elastic moduli and viscosities of biomaterials (and cells)

    CERN Document Server

    Moreno-Flores, Susana; Vivanco, Maria dM; Toca-Herrera, Jose Luis

    2010-01-01

    We show that the atomic force microscope can perform stress relaxation and creep compliance measurements on living cells. We propose a method to obtain the mechanical properties of the studied biomaterial: the relaxation time, the elastic moduli and the viscosity.

  8. Nanoscale imaging of the growth and division of bacterial cells on planar substrates with the atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Van Der Hofstadt, M. [Institut de Bioenginyeria de Catalunya (IBEC), C/ Baldiri i Reixac 11-15, 08028 Barcelona (Spain); Hüttener, M.; Juárez, A. [Institut de Bioenginyeria de Catalunya (IBEC), C/ Baldiri i Reixac 11-15, 08028 Barcelona (Spain); Departament de Microbiologia, Universitat de Barcelona, Avinguda Diagonal 645, 08028 Barcelona (Spain); Gomila, G., E-mail: ggomila@ibecbarcelona.eu [Institut de Bioenginyeria de Catalunya (IBEC), C/ Baldiri i Reixac 11-15, 08028 Barcelona (Spain); Departament d' Electronica, Universitat de Barcelona, C/ Marti i Franqués 1, 08028 Barcelona (Spain)

    2015-07-15

    With the use of the atomic force microscope (AFM), the Nanomicrobiology field has advanced drastically. Due to the complexity of imaging living bacterial processes in their natural growing environments, improvements have come to a standstill. Here we show the in situ nanoscale imaging of the growth and division of single bacterial cells on planar substrates with the atomic force microscope. To achieve this, we minimized the lateral shear forces responsible for the detachment of weakly adsorbed bacteria on planar substrates with the use of the so called dynamic jumping mode with very soft cantilever probes. With this approach, gentle imaging conditions can be maintained for long periods of time, enabling the continuous imaging of the bacterial cell growth and division, even on planar substrates. Present results offer the possibility to observe living processes of untrapped bacteria weakly attached to planar substrates. - Highlights: • Gelatine coatings used to weakly attach bacterial cells onto planar substrates. • Use of the dynamic jumping mode as a non-perturbing bacterial imaging mode. • Nanoscale resolution imaging of unperturbed single living bacterial cells. • Growth and division of single bacteria cells on planar substrates observed.

  9. Mass and Force Sensing of an Adsorbate on a Beam Resonator Sensor

    Directory of Open Access Journals (Sweden)

    Yin Zhang

    2015-06-01

    Full Text Available The mass sensing superiority of a micro-/nano-mechanical resonator sensor over conventional mass spectrometry has been, or at least is being firmly established. Because the sensing mechanism of a mechanical resonator sensor is the shifts of resonant frequencies, how to link the shifts of resonant frequencies with the material properties of an analyte formulates an inverse problem. Besides the analyte/adsorbate mass, many other factors, such as position and axial force, can also cause the shifts of resonant frequencies. The in situ measurement of the adsorbate position and axial force is extremely difficult if not impossible, especially when an adsorbate is as small as a molecule or an atom. Extra instruments are also required. In this study, an inverse problem of using three resonant frequencies to determine the mass, position and axial force is formulated and solved. The accuracy of the inverse problem solving method is demonstrated, and how the method can be used in the real application of a nanomechanical resonator is also discussed. Solving the inverse problem is helpful to the development and application of a mechanical resonator sensor for two reasons: reducing extra experimental equipment and achieving better mass sensing by considering more factors.

  10. Analysis of driving force and exciting voltage for a bi-material infrared resonator

    Science.gov (United States)

    Zhang, Xia; Zhang, Dacheng

    2018-01-01

    For a designed sensor with bi-material resonator which is used to detect infrared (IR) radiation by means of tracking the change in resonance frequency of the resonator with temperature attributed to the IR radiation from targets, in accordance with electromagnetic theory, the relationship between the electrical driving force exerted on the resonator and the exciting voltage applied across two electrodes of the capacitor in the sensor is presented. According to vibration theory, the dependence of the driving force on the exciting voltage is analyzed. The result of analysis is used to guide the vibration mode and frequency-amplitude response simulations of the resonator. The simulation value is approximately equal to the measured value, which demonstrates that the analysis result is effective and practicable.

  11. Plasmon resonance and the imaging of metal-impregnated neurons with the laser scanning confocal microscope

    OpenAIRE

    Thompson, Karen J; Harley, Cynthia M.; Barthel, Grant M; Sanders, Mark A.; Mesce, Karen A.

    2015-01-01

    eLife digest A fresh slice of brain tissue has a fairly uniform appearance, even when viewed under a microscope. To study the neurons and other cells in the brain, scientists must therefore first prepare tissue samples using methods that make it easier to see certain kinds of cells, or particular features of them. One method that has been available for over a century is to use metal particles to stain some of the cells. For example, when the Spanish anatomist Santiago Ram?n y Cajal investigat...

  12. MM99.50 - Surface Topography Characterization Using an Atomic Force Microscope Mounted on a Coordinate Measuring Machine

    DEFF Research Database (Denmark)

    Chiffre, Leonardo De; Hansen, Hans Nørgaard; Kofod, Niels

    1999-01-01

    The paper describes the construction, testing and use of an integrated system for topographic characterization of fine surfaces on parts having relatively big dimensions. An atomic force microscope (AFM) was mounted on a manual three-coordinate measuring machine (CMM) achieving free positioning...... of the AFM probe in space. This means that the limited measuring range of the AFM (40 mu m x 40 mu m x 2.7 um) can be extended by positioning the AFM probe using the movements of the CMM axes (400 mm x 100 mm x 75 mm). Evaluation of the background noise by determining the Sa value of an optical fiat gave...

  13. Atomic force microscope-based single cell force spectroscopy of breast cancer cell lines: an approach for evaluating cellular invasion.

    Science.gov (United States)

    Omidvar, Ramin; Tafazzoli-Shadpour, Mohammad; Shokrgozar, Mohammad Ali; Rostami, Mostafa

    2014-10-17

    The adhesiveness of cancerous cells to their neighboring cells significantly contributes to tumor progression and metastasis. The single-cell force spectroscopy (SCFS) approach was implemented to survey the cell-cell adhesion force between cancerous cells in three cancerous breast cell lines (MCF-7, T47D, and MDA-MB-231). The gene expression levels of two dominant cell adhesion markers (E-cadherin and N-cadherin) were quantified by real-time PCR. Additionally, the local stiffness of the cell bodies was measured by atomic force microscopy (AFM), and the actin cytoskeletal organization was examined by confocal microscopy. Results indicated that the adhesion force between cells was conversely correlated with their invasion potential. The highest adhesion force was observed in the MCF-7 cells. A reduction in cell-cell adhesion, which is required for the detachment of cells from the main tumor during metastasis, is partly due to the loss of E-cadherin expression and the enhanced expression of N-cadherins. The reduced adhesion was accompanied by the softening of cells, as described by the rearrangement of actin filaments through confocal microscopy observations. The softening of the cell body and the reduced cellular adhesiveness are two adaptive mechanisms through which malignant cells achieve the increased deformability, motility, and strong metastasis potential necessary for passage through endothelial junctions and positioning in host tissue. This study presented application of SCFS to survey cell phenotype transformation during cancer progression. The results can be implemented as a platform for further investigations that target the manipulation of cellular adhesiveness and stiffness as a therapeutic choice. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Measuring intermolecular rupture forces with a combined TIRF-optical trap microscope and DNA curtains.

    Science.gov (United States)

    Lee, Ja Yil; Wang, Feng; Fazio, Teresa; Wind, Shalom; Greene, Eric C

    2012-10-05

    We report a new approach to probing DNA-protein interactions by combining optical tweezers with a high-throughput DNA curtains technique. Here we determine the forces required to remove the individual lipid-anchored DNA molecules from the bilayer. We demonstrate that DNA anchored to the bilayer through a single biotin-streptavidin linkage withstands ∼20pN before being pulled free from the bilayer, whereas molecules anchored to the bilayer through multiple attachment points can withstand ⩾65pN; access to this higher force regime is sufficient to probe the responses of protein-DNA interactions to force changes. As a proof-of-principle, we concurrently visualized DNA-bound fluorescently-tagged RNA polymerase while simultaneously stretching the DNA molecules. This work presents a step towards a powerful experimental platform that will enable concurrent visualization of DNA curtains while applying defined forces through optical tweezers. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Nanopipette combined with quartz tuning fork-atomic force microscope for force spectroscopy/microscopy and liquid delivery-based nanofabrication

    Science.gov (United States)

    An, Sangmin; Lee, Kunyoung; Kim, Bongsu; Noh, Haneol; Kim, Jongwoo; Kwon, Soyoung; Lee, Manhee; Hong, Mun-Heon; Jhe, Wonho

    2014-03-01

    This paper introduces a nanopipette combined with a quartz tuning fork-atomic force microscope system (nanopipette/QTF-AFM), and describes experimental and theoretical investigations of the nanoscale materials used. The system offers several advantages over conventional cantilever-based AFM and QTF-AFM systems, including simple control of the quality factor based on the contact position of the QTF, easy variation of the effective tip diameter, electrical detection, on-demand delivery and patterning of various solutions, and in situ surface characterization after patterning. This tool enables nanoscale liquid delivery and nanofabrication processes without damaging the apex of the tip in various environments, and also offers force spectroscopy and microscopy capabilities.

  16. Nanopipette combined with quartz tuning fork-atomic force microscope for force spectroscopy/microscopy and liquid delivery-based nanofabrication.

    Science.gov (United States)

    An, Sangmin; Lee, Kunyoung; Kim, Bongsu; Noh, Haneol; Kim, Jongwoo; Kwon, Soyoung; Lee, Manhee; Hong, Mun-Heon; Jhe, Wonho

    2014-03-01

    This paper introduces a nanopipette combined with a quartz tuning fork-atomic force microscope system (nanopipette/QTF-AFM), and describes experimental and theoretical investigations of the nanoscale materials used. The system offers several advantages over conventional cantilever-based AFM and QTF-AFM systems, including simple control of the quality factor based on the contact position of the QTF, easy variation of the effective tip diameter, electrical detection, on-demand delivery and patterning of various solutions, and in situ surface characterization after patterning. This tool enables nanoscale liquid delivery and nanofabrication processes without damaging the apex of the tip in various environments, and also offers force spectroscopy and microscopy capabilities.

  17. Optimizing 1-μs-Resolution Single-Molecule Force Spectroscopy on a Commercial Atomic Force Microscope.

    Science.gov (United States)

    Edwards, Devin T; Faulk, Jaevyn K; Sanders, Aric W; Bull, Matthew S; Walder, Robert; LeBlanc, Marc-Andre; Sousa, Marcelo C; Perkins, Thomas T

    2015-10-14

    Atomic force microscopy (AFM)-based single-molecule force spectroscopy (SMFS) is widely used to mechanically measure the folding and unfolding of proteins. However, the temporal resolution of a standard commercial cantilever is 50-1000 μs, masking rapid transitions and short-lived intermediates. Recently, SMFS with 0.7-μs temporal resolution was achieved using an ultrashort (L = 9 μm) cantilever on a custom-built, high-speed AFM. By micromachining such cantilevers with a focused ion beam, we optimized them for SMFS rather than tapping-mode imaging. To enhance usability and throughput, we detected the modified cantilevers on a commercial AFM retrofitted with a detection laser system featuring a 3-μm circular spot size. Moreover, individual cantilevers were reused over multiple days. The improved capabilities of the modified cantilevers for SMFS were showcased by unfolding a polyprotein, a popular biophysical assay. Specifically, these cantilevers maintained a 1-μs response time while eliminating cantilever ringing (Q ≅ 0.5). We therefore expect such cantilevers, along with the instrumentational improvements to detect them on a commercial AFM, to accelerate high-precision AFM-based SMFS studies.

  18. Comparison of Macroscopic Pathology Measurements With Magnetic Resonance Imaging and Assessment of Microscopic Pathology Extension for Colorectal Liver Metastases

    Energy Technology Data Exchange (ETDEWEB)

    Mendez Romero, Alejandra, E-mail: a.mendezromero@erasmusmc.nl [Department of Radiation Oncology, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Verheij, Joanne [Department of Pathology, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Dwarkasing, Roy S. [Department of Radiology, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Seppenwoolde, Yvette [Department of Radiation Oncology, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Redekop, William K. [Institute for Medical Technology Assessment, Erasmus University, Rotterdam (Netherlands); Zondervan, Pieter E. [Department of Pathology, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Nowak, Peter J.C.M. [Department of Radiation Oncology, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Ijzermans, Jan N.M. [Department of Surgery, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Levendag, Peter C.; Heijmen, Ben J.M. [Department of Radiation Oncology, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Verhoef, Cornelis [Department of Surgery, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam (Netherlands)

    2012-01-01

    Purpose: To compare pathology macroscopic tumor dimensions with magnetic resonance imaging (MRI) measurements and to establish the microscopic tumor extension of colorectal liver metastases. Methods and Materials: In a prospective pilot study we included patients with colorectal liver metastases planned for surgery and eligible for MRI. A liver MRI was performed within 48 hours before surgery. Directly after surgery, an MRI of the specimen was acquired to measure the degree of tumor shrinkage. The specimen was fixed in formalin for 48 hours, and another MRI was performed to assess the specimen/tumor shrinkage. All MRI sequences were imported into our radiotherapy treatment planning system, where the tumor and the specimen were delineated. For the macroscopic pathology analyses, photographs of the sliced specimens were used to delineate and reconstruct the tumor and the specimen volumes. Microscopic pathology analyses were conducted to assess the infiltration depth of tumor cell nests. Results: Between February 2009 and January 2010 we included 13 patients for analysis with 21 colorectal liver metastases. Specimen and tumor shrinkage after resection and fixation was negligible. The best tumor volume correlations between MRI and pathology were found for T1-weighted (w) echo gradient sequence (r{sub s} = 0.99, slope = 1.06), and the T2-w fast spin echo (FSE) single-shot sequence (r{sub s} = 0.99, slope = 1.08), followed by the T2-w FSE fat saturation sequence (r{sub s} = 0.99, slope = 1.23), and the T1-w gadolinium-enhanced sequence (r{sub s} = 0.98, slope = 1.24). We observed 39 tumor cell nests beyond the tumor border in 12 metastases. Microscopic extension was found between 0.2 and 10 mm from the main tumor, with 90% of the cases within 6 mm. Conclusions: MRI tumor dimensions showed a good agreement with the macroscopic pathology suggesting that MRI can be used for accurate tumor delineation. However, microscopic extensions found beyond the tumor border indicate

  19. Implementation and characterization of a quartz tuning fork based probe consisted of discrete resonators for dynamic mode atomic force microscopy.

    Science.gov (United States)

    Akiyama, Terunobu; de Rooij, Nicolaas F; Staufer, Urs; Detterbeck, Manfred; Braendlin, Dominik; Waldmeier, Simon; Scheidiger, Martin

    2010-06-01

    The quartz tuning fork based probe {e.g., Akiyama et al. [Appl. Surf. Sci. 210, 18 (2003)]}, termed "A-Probe," is a self-sensing and self-actuating (exciting) probe for dynamic mode atomic force microscope (AFM) operation. It is an oscillatory force sensor consisting of the two discrete resonators. This paper presents the investigations on an improved A-Probe: its batch fabrication and assembly, mounting on an AFM head, electrical setup, characterization, and AFM imaging. The fundamental features of the A-Probe are electrically and optically characterized in "approach-withdraw" experiments. Further investigations include the frequency response of an A-Probe to small mechanical vibrations externally applied to the tip and the effective loading force yielding between the tip and the sample during the periodic contact. Imaging of an electronic chip, a compact disk stamper, carbon nanotubes, and Si beads is demonstrated with this probe at ambient conditions in the so-called frequency modulation mode. A special probe substrate, which can snap on a receptacle fixed on an AFM head, and a special holder including a preamplifier electronic are introduced. We hope that the implementation and characterization of the A-Probe described in this paper will provide hints for new scanning probe techniques.

  20. MEMS-Based Force-Detected Nuclear Magnetic Resonance (FDNMR) Spectrometer

    Science.gov (United States)

    Lee, Choonsup; Butler, Mark C.; Elgammal, Ramez A.; George, Thomas; Hunt, Brian; Weitekamp, Daniel P.

    2006-01-01

    Nuclear Magnetic Resonance (NMR) spectroscopy allows assignment of molecular structure by acquiring the energy spectrum of nuclear spins in a molecule, and by interpreting the symmetry and positions of resonance lines in the spectrum. As such, NMR has become one of the most versatile and ubiquitous spectroscopic methods. Despite these tremendous successes, NMR experiments suffer from inherent low sensitivity due to the relatively low energy of photons in the radio frequency (rt) region of the electromagnetic spectrum. Here, we describe a high-resolution spectroscopy in samples with diameters in the micron range and below. We have reported design and fabrication of force-detected nuclear magnetic resonance (FDNMR).

  1. Measurement and correction of microscopic head motion during magnetic resonance imaging of the brain.

    Directory of Open Access Journals (Sweden)

    Julian Maclaren

    Full Text Available Magnetic resonance imaging (MRI is a widely used method for non-invasive study of the structure and function of the human brain. Increasing magnetic field strengths enable higher resolution imaging; however, long scan times and high motion sensitivity mean that image quality is often limited by the involuntary motion of the subject. Prospective motion correction is a technique that addresses this problem by tracking head motion and continuously updating the imaging pulse sequence, locking the imaging volume position and orientation relative to the moving brain. The accuracy and precision of current MR-compatible tracking systems and navigator methods allows the quantification and correction of large-scale motion, but not the correction of very small involuntary movements in six degrees of freedom. In this work, we present an MR-compatible tracking system comprising a single camera and a single 15 mm marker that provides tracking precision in the order of 10 m and 0.01 degrees. We show preliminary results, which indicate that when used for prospective motion correction, the system enables improvement in image quality at both 3 T and 7 T, even in experienced and cooperative subjects trained to remain motionless during imaging. We also report direct observation and quantification of the mechanical ballistocardiogram (BCG during simultaneous MR imaging. This is particularly apparent in the head-feet direction, with a peak-to-peak displacement of 140 m.

  2. Humidity-Dependent Bacterial Cells Functional Morphometry Investigations Using Atomic Force Microscope

    OpenAIRE

    Hike Nikiyan; Alexey Vasilchenko; Dmitry Deryabin

    2010-01-01

    The effect of a relative humidity (RH) in a range of 93–65% on morphological and elastic properties of Bacillus cereus and Escherichia coli cells was evaluated using atomic force microscopy. It is shown that gradual dehumidification of bacteria environment has no significant effect on cell dimensional features and considerably decreases them only at 65% RH. The increasing of the bacteria cell wall roughness and elasticity occurs at the same time. Observed changes indicate that morphological p...

  3. Direct visualization and identification of biofunctionalized nanoparticles using a magnetic atomic force microscope.

    Science.gov (United States)

    Block, Stephan; Glöckl, Gunnar; Weitschies, Werner; Helm, Christiane A

    2011-09-14

    Because of its outstanding ability to image and manipulate single molecules, atomic force microscopy (AFM) established itself as a fundamental technique in nanobiotechnology. (1) We present a new modality that distinguishes single nanoparticles by the surrounding magnetic field gradient. Diamagnetic gold and superparamagnetic iron oxide nanoparticles become discernible under ambient conditions. Images of proteins, magnetolabeled with nanoparticles, demonstrate the first steps toward a magnetic analogue to fluorescence microscopy, which combines nanoscale lateral resolution of AFM with unambiguous detection of magnetic markers.

  4. Imaging Carbon Nanotubes in High Performance Polymer Composites via Magnetic Force Microscope

    Science.gov (United States)

    Lillehei, Peter T.; Park, Cheol; Rouse, Jason H.; Siochi, Emilie J.; Bushnell, Dennis M. (Technical Monitor)

    2002-01-01

    Application of carbon nanotubes as reinforcement in structural composites is dependent on the efficient dispersion of the nanotubes in a high performance polymer matrix. The characterization of such dispersion is limited by the lack of available tools to visualize the quality of the matrix/carbon nanotube interaction. The work reported herein demonstrates the use of magnetic force microscopy (MFM) as a promising technique for characterizing the dispersion of nanotubes in a high performance polymer matrix.

  5. Characterizing the surface charge of clay minerals with Atomic Force Microscope (AFM

    Directory of Open Access Journals (Sweden)

    Yuan Guo

    2017-05-01

    Full Text Available The engineering properties of clayey soils, including fluid permeability, erosion resistance and cohesive strength, are quite different from those of non-cohesive soils. This is mainly due to their small platy particle shape and the surrounding diffuse double layer structure. By using the Atomic Force Microscopy (AFM, the surface topography and the interaction force between the silicon dioxide tip and the kaolinite/montmorillonite clay minerals have been measured in the 1.0 mM NaCl solution at neutral pH. From this, the surface potential of the clay minerals is determined by mathematical regression analyses using the DLVO model. The length/thickness ratio of kaolinite and montmorillonite particles measured ranges from 8.0 to 15.0. The surface potential and surface charge density vary with particles. The average surface potential of montmorillonite is −62.8 ± 10.6 mV, and the average surface potential of kaolinite is −40.9 ± 15.5 mV. The measured results help to understand the clay sediment interaction, and will be used to develop interparticle force model to simulate sediment transport during erosion process.

  6. Detection of lipopolysaccharide induced inflammatory responses in RAW264.7 macrophages using atomic force microscope.

    Science.gov (United States)

    Pi, Jiang; Li, Ting; Liu, Jianxin; Su, Xiaohui; Wang, Rui; Yang, Fen; Bai, Haihua; Jin, Hua; Cai, Jiye

    2014-10-01

    In recent years, LPS activated RAW264.7 cells are widely used as an in vitro inflammatory model for the screen of effective anti-inflammation drugs and the investigation of exact anti-inflammation mechanism of these drugs. But up to now, there are few data about the effect of LPS on the morphology, especially on the membrane ultrastructure and bio-mechanical properties of RAW264.7 macrophages. In this work, the topographical and biophysical changes of RAW264.7 macrophages upon LPS stimulation are detected by high resolution atomic force microscopy (AFM). The AFM results suggested that LPS activated RAW264.7 macrophages changed to be much bigger than control cells with some holes emerged on cell surface. The size of membrane protein clusters and the roughness of membrane significantly increased after LPS exposure. In addition, the AFM force measurement results demonstrated that LPS stimulation increased the adhesion force of RAW264.7 macrophages, and also increased the stiffness of RAW264.7 macrophages, which were attributed to the re-distribution of intracellular F-actin structures induced by LPS. These findings suggested that LPS stimulation could also induce the pathophysiological changes of RAW264.7 macrophages, which would benefit our understanding of the inflammatory processes in macrophages upon pathogen stimulation at nano-scale. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Noncontact Viscoelastic Imaging of Living Cells Using a Long-Needle Atomic Force Microscope with Dual-Frequency Modulation

    Science.gov (United States)

    Guan, Dongshi; Charlaix, Elisabeth; Qi, Robert Z.; Tong, Penger

    2017-10-01

    Imaging of surface topography and elasticity of living cells can provide insight into the roles played by the cells' volumetric and mechanical properties and their response to external forces in regulating the essential cellular events and functions. Here, we report a unique technique of noncontact viscoelastic imaging of live cells using atomic force microscopy (AFM) with a long-needle glass probe. Because only the probe tip is placed in a liquid medium near the cell surface, the AFM cantilever in air functions well under dual-frequency modulation, retaining its high-quality resonant modes. The probe tip interacts with the cell surface through a minute hydrodynamic flow in the nanometer-thin gap region between them without physical contact. Quantitative measurements of the cell height, volume, and Young's modulus are conducted simultaneously. The experiment demonstrates that the long-needle AFM has a wide range of applications in the study of cell mechanics.

  8. Note: Guaranteed collocated multimode control of an atomic force microscope cantilever using on-chip piezoelectric actuation and sensing

    Science.gov (United States)

    Ruppert, Michael G.; Yong, Yuen K.

    2017-08-01

    The quality (Q) factor is an important parameter of the resonance of the microcantilever as it determines both imaging bandwidth and force sensitivity. The ability to control the Q factor of multiple modes is believed to be of great benefit for atomic force microscopy techniques involving multiple eigenmodes. In this paper, we propose a novel cantilever design employing multiple piezoelectric transducers which are used for separated actuation and sensing, leading to guaranteed collocation of the first eight eigenmodes up to 3 MHz. The design minimizes the feedthrough usually observed with these systems by incorporating a guard trace on the cantilever chip. As a result, a multimode Q controller is demonstrated to be able to modify the quality factor of the first two eigenmodes over up to four orders of magnitude without sacrificing robust stability.

  9. Measurement and deposition of nanometer-scale Cu dot using an atomic force microscope with a nanopipette probe in liquid condition

    Science.gov (United States)

    Ito, So; Yamazaki, Koji; Iwata, Futoshi

    2011-12-01

    In this study, we developed novel techniques of nanometer-scale measurement and deposition using an atomic force microscope (AFM) with a nanopipette in liquid condition. The nanopipette, filled with CuSO4 electrolyte solution, was employed as the AFM probe. Observation and deposition of nanometer-scale Cu dots were carried out using the nanopipette probe. In order to avoid drying of the nanopipette solution and clogging of the probe-edge aperture, Cu dots were deposited and measured in liquid condition. As for the measurement of the surface, the nanopipette probe was glued on a tuning fork quartz crystal resonator (TF-QCR) to detect a probe oscillation and vertically oscillated to use a method of frequency modulation in tapping-mode AFM. With regard to the deposition of nanometer-scale Cu dot, an electrode wire inside the electrolyte-filled nanopipette and conductive surface of Au coated glass slide were employed as the anode and cathode, respectively. By utilizing the probe-surface distance control during the deposition, nanometerscale Cu dot were successfully deposited on Au surface without the diffusion. Then, the deposited dots were observed by using the nanopipette probe. This technique of the local deposition in the liquid would be applicable for various fields such as fabrication of micro/nanometer-scale devices and arrangement of biological samples.

  10. A single-cell scraper based on an atomic force microscope for detaching a living cell from a substrate

    Energy Technology Data Exchange (ETDEWEB)

    Iwata, Futoshi, E-mail: iwata.futoshi@shizuoka.ac.jp [Department of Mechanical Engineering, Faculty of Engineering, Shizuoka University, Johoku, Naka-ku, Hamamatsu 432-8561 (Japan); Research Institute of Electronics, Shizuoka University, Johoku, Naka-ku, Hamamatsu 432-8011 (Japan); Adachi, Makoto; Hashimoto, Shigetaka [Department of Mechanical Engineering, Faculty of Engineering, Shizuoka University, Johoku, Naka-ku, Hamamatsu 432-8561 (Japan)

    2015-10-07

    We describe an atomic force microscope (AFM) manipulator that can detach a single, living adhesion cell from its substrate without compromising the cell's viability. The micrometer-scale cell scraper designed for this purpose was fabricated from an AFM micro cantilever using focused ion beam milling. The homemade AFM equipped with the scraper was compact and standalone and could be mounted on a sample stage of an inverted optical microscope. It was possible to move the scraper using selectable modes of operation, either a manual mode with a haptic device or a computer-controlled mode. The viability of the scraped single cells was evaluated using a fluorescence dye of calcein-acetoxymethl ester. Single cells detached from the substrate were collected by aspiration into a micropipette capillary glass using an electro-osmotic pump. As a demonstration, single HeLa cells were selectively detached from the substrate and collected by the micropipette. It was possible to recultivate HeLa cells from the single cells collected using the system.

  11. Note: Mechanical etching of atomic force microscope tip and microsphere attachment for thermal radiation scattering enhancement.

    Science.gov (United States)

    Brissinger, D; Parent, G; Lacroix, D

    2013-12-01

    This Note describes a mechanical etching technique which can be used to prepare silicon tips used in atomic force microscopy apparatus. For such devices, dedicated tips with specific shapes are now commonly used to probe surfaces. Yet, the control of the tip morphology where characteristic scales are lower than 1 μm remains a real challenge. Here, we detail a controlled etching process of AFM probes apex allowing micrometer-sized sphere attachment. The technique used and influent parameters are discussed and SEM images of the achieved tips are given. Deceptive problems and drawbacks that might occur during the process are also covered.

  12. Influence of measuring parameters on the accuracy of atomic force microscope in industrial applications

    DEFF Research Database (Denmark)

    Tosello, Guido; Antico, Andrea; Hansen, Hans Nørgaard

    2009-01-01

    as in the evaluation of final product characteristics. The paper considers quantitative application of AFM measurements for industrial applications. In particular the influence and subsequent optimization of scanning parameters on the precision of AFM maps is discussed, with particular attention to scan speed...... and interaction force when measuring a one-dimensional grating with triangular profile. The aim is then maximization of information from collected data and minimization of measurement variability and scan time. Optimized scan setting is then applied to measure surface defects of micro injection moulded components...

  13. Atomic force microscope studies of fullerene films - Highly stable C60 fcc (311) free surfaces

    Science.gov (United States)

    Snyder, Eric J.; Tong, William M.; Williams, R. S.; Anz, Samir J.; Anderson, Mark S.

    1991-01-01

    Atomic force microscopy and X-ray diffractometry were used to study 1500 A-thick films of pure C60 grown by sublimation in ultrahigh vacuum onto a CaF2 (111) substrte. Topographs of the films did not reveal the expected close-packed structures, but they showed instead large regions that correspond to a face-centered cubic (311) surface and distortions of this surface. The open (311) structure may have a relatively low free energy because the low packing density contributes to a high entropy of the exposed surface.

  14. Low-volume liquid delivery and nanolithography using a nanopipette combined with a quartz tuning fork-atomic force microscope.

    Science.gov (United States)

    An, Sangmin; Stambaugh, Corey; Kim, Gunn; Lee, Manhee; Kim, Yonghee; Lee, Kunyoung; Jhe, Wonho

    2012-10-21

    Electric-field-induced low-volume liquid ejection under ambient conditions was realized at a low bias potential of 12 V via a nanopipette (aperture diameter of 30 nm) combined with a non-contact, distance-regulated (within 10 nm) quartz tuning fork-atomic force microscope. A capillary-condensed water meniscus, spontaneously formed in the tip-substrate nanogap, reduces the ejection barrier by four orders of magnitude, facilitating nanoliquid ejection and subsequent liquid transport/dispersion onto the substrate without contact damage from the pipette. A study of nanofluidics through a free-standing liquid nanochannel and nanolithography was performed with this technique. This is an important breakthrough for various applications in controlled nanomaterial-delivery and selective deposition, such as multicolor nanopatterning and nano-inkjet devices.

  15. The multi-position calibration of the stiffness for atomic-force microscope cantilevers based on vibration

    Science.gov (United States)

    Zheng, Yelong; Song, Le; Hu, Gang; Cai, Xue; Liu, Hongguang; Ma, Jinyu; Zhao, Meirong; Fang, Fengzhou

    2015-05-01

    Calibration of the stiffness of atomic force microscope (AFM) cantilevers is critical for industry and academic research. The multi-position calibration method for AFM cantilevers based on vibration is investigated. The position providing minimum uncertainty is deduced. The validity of the multi-position approach is shown via theoretical and experimental means. We applied it to the recently developed vibration method using an AFM cantilever with a normal stiffness of 0.1 N m-1. The standard deviation of the measured stiffness is 0.002 N m-1 with a mean value of 0.189 N m-1 and the relative combined uncertainty is approximately 7%, which is better than the approach using the single position at the tip of the cantilever.

  16. Note: Fabrication of a fast-response and user-friendly environmental chamber for atomic force microscopes

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Yanfeng; Hui, Fei; Shi, Yuanyuan; Han, Tingting; Song, Xiaoxue; Pan, Chengbin; Lanza, Mario, E-mail: mlanza@suda.edu.cn [Institute of Functional Nano & Soft Materials, Soochow University, Collaborative Innovation Center of Suzhou Nano Science & Technology, 199 Ren-Ai Road, Suzhou 215123 (China)

    2015-10-15

    The atomic force microscope is one of the most widespread tools in science, but many suppliers do not provide a competitive solution to make experiments in controlled atmospheres. Here, we provide a solution to this problem by fabricating a fast-response and user-friendly environmental chamber. We corroborate the correct functioning of the chamber by studying the formation of local anodic oxidation on a silicon sample (biased under opposite polarities), an effect that can be suppressed by measuring in a dry nitrogen atmosphere. The usefulness of this chamber goes beyond the example here presented, and it could be used in many other fields of science, including physics, mechanics, microelectronics, nanotechnology, medicine, and biology.

  17. Note: Fabrication of a fast-response and user-friendly environmental chamber for atomic force microscopes

    Science.gov (United States)

    Ji, Yanfeng; Hui, Fei; Shi, Yuanyuan; Han, Tingting; Song, Xiaoxue; Pan, Chengbin; Lanza, Mario

    2015-10-01

    The atomic force microscope is one of the most widespread tools in science, but many suppliers do not provide a competitive solution to make experiments in controlled atmospheres. Here, we provide a solution to this problem by fabricating a fast-response and user-friendly environmental chamber. We corroborate the correct functioning of the chamber by studying the formation of local anodic oxidation on a silicon sample (biased under opposite polarities), an effect that can be suppressed by measuring in a dry nitrogen atmosphere. The usefulness of this chamber goes beyond the example here presented, and it could be used in many other fields of science, including physics, mechanics, microelectronics, nanotechnology, medicine, and biology.

  18. Electron spin resonance microscopic imaging of oxygen concentration in cancer spheroids

    Science.gov (United States)

    Hashem, Mada; Weiler-Sagie, Michal; Kuppusamy, Periannan; Neufeld, Gera; Neeman, Michal; Blank, Aharon

    2015-07-01

    Oxygen (O2) plays a central role in most living organisms. The concentration of O2 is important in physiology and pathology. Despite the importance of accurate knowledge of the O2 levels, there is very limited capability to measure with high spatial resolution its distribution in millimeter-scale live biological samples. Many of the current oximetric methods, such as oxygen microelectrodes and fluorescence lifetime imaging, are compromised by O2 consumption, sample destruction, invasiveness, and difficulty to calibrate. Here, we present a new method, based on the use of the pulsed electron spin resonance (ESR) microimaging technique to obtain a 3D mapping of oxygen concentration in millimeter-scale biological samples. ESR imaging requires the incorporation of a suitable stable and inert paramagnetic spin probe into the desirable object. In this work, we use microcrystals of a paramagnetic spin probe in a new crystallographic packing form (denoted tg-LiNc-BuO). These paramagnetic species interact with paramagnetic oxygen molecules, causing a spectral line broadening that is linearly proportional to the oxygen concentration. Typical ESR results include 4D spatial-spectral images that give an indication about the oxygen concentration in different regions of the sample. This new oximetry microimaging method addresses all the problems mentioned above. It is noninvasive, sensitive to physiological oxygen levels, and easy to calibrate. Furthermore, in principle, it can be used for repetitive measurements without causing cell damage. The tissue model used in this research is spheroids of Human Colorectal carcinoma cell line (HCT-116) with a typical diameter of ∼600 μm. Most studies of the microenvironmental O2 conditions inside such viable spheroids carried out in the past used microelectrodes, which require an invasive puncturing of the spheroid and are also not applicable to 3D O2 imaging. High resolution 3D oxygen maps could make it possible to evaluate the

  19. Low-volume liquid delivery and nanolithography using a nanopipette combined with a quartz tuning fork-atomic force microscope

    Science.gov (United States)

    An, Sangmin; Stambaugh, Corey; Kim, Gunn; Lee, Manhee; Kim, Yonghee; Lee, Kunyoung; Jhe, Wonho

    2012-09-01

    Electric-field-induced low-volume liquid ejection under ambient conditions was realized at a low bias potential of 12 V via a nanopipette (aperture diameter of 30 nm) combined with a non-contact, distance-regulated (within 10 nm) quartz tuning fork-atomic force microscope. A capillary-condensed water meniscus, spontaneously formed in the tip-substrate nanogap, reduces the ejection barrier by four orders of magnitude, facilitating nanoliquid ejection and subsequent liquid transport/dispersion onto the substrate without contact damage from the pipette. A study of nanofluidics through a free-standing liquid nanochannel and nanolithography was performed with this technique. This is an important breakthrough for various applications in controlled nanomaterial-delivery and selective deposition, such as multicolor nanopatterning and nano-inkjet devices.Electric-field-induced low-volume liquid ejection under ambient conditions was realized at a low bias potential of 12 V via a nanopipette (aperture diameter of 30 nm) combined with a non-contact, distance-regulated (within 10 nm) quartz tuning fork-atomic force microscope. A capillary-condensed water meniscus, spontaneously formed in the tip-substrate nanogap, reduces the ejection barrier by four orders of magnitude, facilitating nanoliquid ejection and subsequent liquid transport/dispersion onto the substrate without contact damage from the pipette. A study of nanofluidics through a free-standing liquid nanochannel and nanolithography was performed with this technique. This is an important breakthrough for various applications in controlled nanomaterial-delivery and selective deposition, such as multicolor nanopatterning and nano-inkjet devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr30972f

  20. Atomic force and optical near-field microscopic investigations of polarization holographic gratings in a liquid crystalline azobenzene side-chain polyester

    DEFF Research Database (Denmark)

    Ramanujam, P.S.; Holme, N.C.R.; Hvilsted, S.

    1996-01-01

    Atomic force and scanning near-field optical microscopic investigations have been carried out on a polarization holographic grating recorded in an azobenzene side-chain Liquid crystalline polyester. It has been found that immediately following laser irradiation, a topographic surface grating......-field optical microscopic scanning of the grating reveals, however, that the bulk of the film remains optically anisotropic. (C) 1996 American Institute of Physics....

  1. Mechanical properties of cellulose nanomaterials studied by contact resonance atomic force microscopy

    Science.gov (United States)

    Ryan Wagner; Robert J. Moon; Arvind Raman

    2016-01-01

    Quantification of the mechanical properties of cellulose nanomaterials is key to the development of new cellulose nanomaterial based products. Using contact resonance atomic force microscopy we measured and mapped the transverse elastic modulus of three types of cellulosic nanoparticles: tunicate cellulose nanocrystals, wood cellulose nanocrystals, and wood cellulose...

  2. High Performance Nuclear Magnetic Resonance Imaging Using Magnetic Resonance Force Microscopy

    Science.gov (United States)

    2013-12-12

    We collected hysteresis curves to investigate the ferromagnetism as reported in the literature [34]. For our measurements, we took both eld cooled...Micron-Size Ferromagnet . Physical Review Letters, 92(3) 037205 (2004) [22] A. Z. Genack and A. G. Redeld. Theory of nuclear spin diusion in a...International Workshop on Spin Mechanics, Tokai,Japan, 24–26 February 2013, “Nanoscale scanning probe ferromagnetic resonance imaging using localized

  3. Microscopic optical potential with two and three body forces for nucleon–nucleus scattering

    Directory of Open Access Journals (Sweden)

    Gambhir Y.K.

    2014-03-01

    Full Text Available The proton - nucleus optical potentials generated by folding the calculated complex, density and energy dependent g- matrices (with and without three-body forces (TBF: Urbana IX (UVIX and TNI over the target nucleon density distributions obtained from the relativistic mean field theory, are used for the calculation of the differential cross section dσ / dθ , polarization Ay , spin rotation function (Q. for 65 and 200 MeV polarized proton incident on 40Ca and 208Pb . The agreement with the experiment is rather impressive. It is found that the inclusion of TBF (Urbana IX UVIX and TNI reduces the strength of the central part of the optical potential in the nuclear interior and affects the calculated spin-orbit potential only marginally and leads to an improvement in the agreement with the corresponding experimental results.

  4. Note: A stand on the basis of atomic force microscope to study substrates for imaging optics

    Energy Technology Data Exchange (ETDEWEB)

    Chkhalo, N. I.; Salashchenko, N. N.; Zorina, M. V. [Department of Multilayer Optics, Institute for Physics of Microstructures of the Russian Academy of Sciences, GSP-105, 603950 Nizhny Novgorod (Russian Federation)

    2015-01-15

    A description of a stand based on atomic force microscopy (AFM) for roughness measurements of large optical components with arbitrary surfaces is given. The sample under study is mounted on a uniaxial goniometer which allows the sample to be tilted in the range of ±30°. The inclination enables the local normal along the axis of the probe to be established at any point of the surface under study. A comparison of the results of the measurement of noise and roughness of a flat quartz sample, in the range of spatial frequencies 0.025–70 μm{sup −1}, obtained from “standard” AFM and developed versions is given. Within the experimental error, the measurement results were equivalent. Examples of applications of the stand for the study of substrates for X-ray optics are presented.

  5. Humidity-Dependent Bacterial Cells Functional Morphometry Investigations Using Atomic Force Microscope

    Directory of Open Access Journals (Sweden)

    Hike Nikiyan

    2010-01-01

    Full Text Available The effect of a relative humidity (RH in a range of 93–65% on morphological and elastic properties of Bacillus cereus and Escherichia coli cells was evaluated using atomic force microscopy. It is shown that gradual dehumidification of bacteria environment has no significant effect on cell dimensional features and considerably decreases them only at 65% RH. The increasing of the bacteria cell wall roughness and elasticity occurs at the same time. Observed changes indicate that morphological properties of B. cereus are rather stable in wide range of relative humidity, whereas E. coli are more sensitive to drying, significantly increasing roughness and stiffness parameters at RH ≤ 84% RH. It is discussed the dependence of the response features on differences in cell wall structure of gram-positive and gram-negative bacterial cells.

  6. The possibility of multi-layer nanofabrication via atomic force microscope-based pulse electrochemical nanopatterning

    Science.gov (United States)

    Kim, Uk Su; Morita, Noboru; Lee, Deug Woo; Jun, Martin; Park, Jeong Woo

    2017-05-01

    Pulse electrochemical nanopatterning, a non-contact scanning probe lithography process using ultrashort voltage pulses, is based primarily on an electrochemical machining process using localized electrochemical oxidation between a sharp tool tip and the sample surface. In this study, nanoscale oxide patterns were formed on silicon Si (100) wafer surfaces via electrochemical surface nanopatterning, by supplying external pulsed currents through non-contact atomic force microscopy. Nanoscale oxide width and height were controlled by modulating the applied pulse duration. Additionally, protruding nanoscale oxides were removed completely by simple chemical etching, showing a depressed pattern on the sample substrate surface. Nanoscale two-dimensional oxides, prepared by a localized electrochemical reaction, can be defined easily by controlling physical and electrical variables, before proceeding further to a layer-by-layer nanofabrication process.

  7. Adsorption characteristics of P(3HB) depolymerase as evaluated by surface plasmon resonance and atomic force microscopy.

    Science.gov (United States)

    Matsumoto, Nobuhiko; Fujita, Masahiro; Hiraishi, Tomohiro; Abe, Hideki; Maeda, Mizuo

    2008-11-01

    Molecular recognition of poly[(R)-3-hydroxybutyrate] (P(3HB)) depolymerase from Ralstonia pickettii T1 to the surfaces of biodegradable aliphatic polyesters such as P(3HB) and poly(L-lactic acid) (PLLA) was examined from the viewpoints of kinetics and dynamics. To determine the kinetic parameters on the interaction between the substrate-binding domain (SBD) of P(3HB) depolymerase and various polymer substrates with different chemical structures, surface plasmon resonance (SPR) measurements were performed. On the other hand, using an atomic force microscopic (AFM) cantilever tip functionalized with the SBD of P(3HB) depolymerase, the mechanical parameters such as unbinding force to the polymer surfaces were measured. Both the SPR and AFM measurements showed that the SBD has a high affinity to P(3HB) and PLLA. From the results of kinetics and dynamics, the energy potential landscape of SBD-polymer interaction was disclosed on the basis of a phenomenological model, and the mechanism of the interaction was discussed.

  8. Effect of cantilever geometry on the optical lever sensitivities and thermal noise method of the atomic force microscope.

    Science.gov (United States)

    Sader, John E; Lu, Jianing; Mulvaney, Paul

    2014-11-01

    Calibration of the optical lever sensitivities of atomic force microscope (AFM) cantilevers is especially important for determining the force in AFM measurements. These sensitivities depend critically on the cantilever mode used and are known to differ for static and dynamic measurements. Here, we calculate the ratio of the dynamic and static sensitivities for several common AFM cantilevers, whose shapes vary considerably, and experimentally verify these results. The dynamic-to-static optical lever sensitivity ratio is found to range from 1.09 to 1.41 for the cantilevers studied - in stark contrast to the constant value of 1.09 used widely in current calibration studies. This analysis shows that accuracy of the thermal noise method for the static spring constant is strongly dependent on cantilever geometry - neglect of these dynamic-to-static factors can induce errors exceeding 100%. We also discuss a simple experimental approach to non-invasively and simultaneously determine the dynamic and static spring constants and optical lever sensitivities of cantilevers of arbitrary shape, which is applicable to all AFM platforms that have the thermal noise method for spring constant calibration.

  9. Acquire an Bruker Dimension FastScanTM Atomic Force Microscope (AFM) for Materials, Physical and Biological Science Research and Education

    Science.gov (United States)

    2016-04-14

    SECURITY CLASSIFICATION OF: The DOD HBCU/MI instrumentation award provided us a rare opportunity to acquire a Bruker Dimension FastScanTM Atomic ...UU 14-04-2016 1-Jan-2015 31-Jan-2016 Final Report: Acquire an Bruker Dimension FastScanTM Atomic Force Microscope (AFM) for Materials, Physical and...NAME(S) AND ADDRESS (ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 Atomic Force Microscope, self-assembly

  10. Nuclear pairing from microscopic forces: Singlet channels and higher-partial waves

    Science.gov (United States)

    Maurizio, Stefano; Holt, Jeremy W.; Finelli, Paolo

    2014-10-01

    Background: An accurate description of nuclear pairing gaps is extremely important for understanding static and dynamic properties of the inner crusts of neutron stars and to explain their cooling process. Purpose: We plan to study the behavior of the pairing gaps ΔF as a function of the Fermi momentum kF for neutron and nuclear matter in all relevant angular momentum channels where superfluidity is believed to naturally emerge. The calculations will employ realistic chiral nucleon-nucleon potentials with the inclusion of three-body forces and self-energy effects. Methods: The superfluid states of neutron and nuclear matter are studied by solving the BCS gap equation for chiral nuclear potentials using the method suggested by Khodel et al., where the original gap equation is replaced by a coupled set of equations for the dimensionless gap function χ (k) defined by Δ(k )=ΔFχ(k) and a nonlinear algebraic equation for the gap magnitude ΔF=Δ(kF) at the Fermi surface. This method is numerically stable even for small pairing gaps, such as that encountered in the coupled 3PF2 partial wave. Results: We have successfully applied Khodel's method to singlet (S) and coupled channel (SD and PF) cases in neutron and nuclear matter. Our calculations agree with other ab initio approaches, where available, and provide crucial inputs for future applications in superfluid systems.

  11. The extended wedge method: Atomic force microscope friction calibration for improved tolerance to instrument misalignments, tip offset, and blunt probes

    Science.gov (United States)

    Khare, H. S.; Burris, D. L.

    2013-05-01

    One of the major challenges in understanding and controlling friction is the difficulty in bridging the length and time scales of macroscale contacts and those of the single asperity interactions they comprise. While the atomic force microscope (AFM) offers a unique ability to probe tribological surfaces in a wear-free single-asperity contact, instrument calibration challenges have limited the usefulness of this technique for quantitative nanotribological studies. A number of lateral force calibration techniques have been proposed and used, but none has gained universal acceptance due to practical considerations, configuration limitations, or sensitivities to unknowable error sources. This paper describes a simple extension of the classic wedge method of AFM lateral force calibration which: (1) allows simultaneous calibration and measurement on any substrate, thus eliminating prior tip damage and confounding effects of instrument setup adjustments; (2) is insensitive to adhesion, PSD cross-talk, transducer/piezo-tube axis misalignment, and shear-center offset; (3) is applicable to integrated tips and colloidal probes; and (4) is generally applicable to any reciprocating friction coefficient measurement. The method was applied to AFM measurements of polished carbon (99.999% graphite) and single crystal MoS2 to demonstrate the technique. Carbon and single crystal MoS2 had friction coefficients of μ = 0.20 ± 0.04 and μ = 0.006 ± 0.001, respectively, against an integrated Si probe. Against a glass colloidal sphere, MoS2 had a friction coefficient of μ = 0.005 ± 0.001. Generally, the measurement uncertainties ranged from 10%-20% and were driven by the effect of actual frictional variation on the calibration rather than calibration error itself (i.e., due to misalignment, tip-offset, or probe radius).

  12. Multi-axis force sensing using a resonant composite piezoelectric plate: model and experiments

    Science.gov (United States)

    Castaño-Cano, Davinson; Grossard, Mathieu; Hubert, Arnaud

    2015-05-01

    Wrist force/torque sensors used in robotic applications increase the performances and flexibility of the automated tasks. They also offer new possibilities in the manufacturing process, where physical contact between the work-piece and environment is required. The wide spreading of these sensors is for now restricted by their features. As an alternative to the existing strain-gauges force sensors, this paper presents a resonant composite structure, which is sensitive to multiple components of force that are considered via the pre-stress effect. Structurally bonded piezoelectric patches are used to bring the structure to its resonance, which is shifted according to applied forces. The relationship between force and frequency shift is modelled considering the multi-physics of this smart structure. This model is built using Hamilton's principle and takes into account pre-stress phenomena. A finite element model (FEM) based on Mindlin theory for plates, has been derived from the analytical model. The FEM model is implemented in MATLAB and compared with commercial FE software. Finally, an experimental prototype validates the model, and shows that it is possible to measure multiple force-components with one single sensing element such as a plate.

  13. Langevin equation with time dependent linear force and periodic load force: stochastic resonance

    Science.gov (United States)

    Sau Fa, Kwok

    2017-11-01

    The motion of a particle described by the Langevin equation with constant diffusion coefficient, time dependent linear force (ω (1+α \\cos ({ω }1t))x) and periodic load force ({A}0\\cos ({{Ω }}t)) is investigated. Analytical solutions for the probability density function (PDF) and n-moment are obtained and analysed. For {ω }1\\gg α ω the influence of the periodic term α \\cos ({ω }1t) is negligible to the PDF and n-moment for any time; this result shows that the statistical averages such as n-moments and the PDF have no access to some information of the system. For small and intermediate values of {ω }1 the influence of the periodic term α \\cos ({ω }1t) to the system is also analysed; in particular the system may present multiresonance. The solutions are obtained in a direct and pedagogical manner readily understandable by graduate students.

  14. Unforced, Forced and Resonance-Forced Waves in a Spherical Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Covey, Curt [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-27

    This technical report discusses a longstanding issue of atmospheric tides in weather-prediction and general circulation models (GCMs). Tidal signatures consistent with observations have appeared in the surface pressure output of GCMs since their inception (Hardy 1968, Hunt and Manabe 1968). Such models, however, are sufficiently complicated that the possibility of “getting the right answer for the wrong reasons” arises. Lindzen et al. (1968, hereafter LBK) showed that wave reflection at the upper boundary of a GCM can artificially enhance the tides. Covey et al. (2011, 2014) found that tidal output from a number of modern GCMs is surprisingly independent of their forcing. This finding is consistent with earlier suggestions that a compensating effect occurs in some models: lowering the model top reduces the forcing (solar heating of the ozone layer) but also enhances spurious wave reflection (Zwiers and Hamilton 1986, Hamilton et al. 2008).

  15. Frequency, amplitude, and phase measurements in contact resonance atomic force microscopies

    Directory of Open Access Journals (Sweden)

    Gheorghe Stan

    2014-03-01

    Full Text Available The resonance frequency, amplitude, and phase response of the first two eigenmodes of two contact-resonance atomic force microscopy (CR-AFM configurations, which differ in the method used to excite the system (cantilever base vs sample excitation, are analyzed in this work. Similarities and differences in the observables of the cantilever dynamics, as well as the different effect of the tip–sample contact properties on those observables in each configuration are discussed. Finally, the expected accuracy of CR-AFM using phase-locked loop detection is investigated and quantification of the typical errors incurred during measurements is provided.

  16. Set-up of a high-resolution 300 mK atomic force microscope in an ultra-high vacuum compatible 3He/10 T cryostat

    Science.gov (United States)

    von Allwörden, H.; Ruschmeier, K.; Köhler, A.; Eelbo, T.; Schwarz, A.; Wiesendanger, R.

    2016-07-01

    The design of an atomic force microscope with an all-fiber interferometric detection scheme capable of atomic resolution at about 500 mK is presented. The microscope body is connected to a small pumped 3He reservoir with a base temperature of about 300 mK. The bakeable insert with the cooling stage can be moved from its measurement position inside the bore of a superconducting 10 T magnet into an ultra-high vacuum chamber, where the tip and sample can be exchanged in situ. Moreover, single atoms or molecules can be evaporated onto a cold substrate located inside the microscope. Two side chambers are equipped with standard surface preparation and surface analysis tools. The performance of the microscope at low temperatures is demonstrated by resolving single Co atoms on Mn/W(110) and by showing atomic resolution on NaCl(001).

  17. Set-up of a high-resolution 300 mK atomic force microscope in an ultra-high vacuum compatible (3)He/10 T cryostat.

    Science.gov (United States)

    von Allwörden, H; Ruschmeier, K; Köhler, A; Eelbo, T; Schwarz, A; Wiesendanger, R

    2016-07-01

    The design of an atomic force microscope with an all-fiber interferometric detection scheme capable of atomic resolution at about 500 mK is presented. The microscope body is connected to a small pumped (3)He reservoir with a base temperature of about 300 mK. The bakeable insert with the cooling stage can be moved from its measurement position inside the bore of a superconducting 10 T magnet into an ultra-high vacuum chamber, where the tip and sample can be exchanged in situ. Moreover, single atoms or molecules can be evaporated onto a cold substrate located inside the microscope. Two side chambers are equipped with standard surface preparation and surface analysis tools. The performance of the microscope at low temperatures is demonstrated by resolving single Co atoms on Mn/W(110) and by showing atomic resolution on NaCl(001).

  18. Resonant Optical Gradient Force Interaction for Nano-Imaging and-Spectroscopy

    Science.gov (United States)

    2016-07-19

    gradient force off-resonance is below the thermal cantilever noise limit of a room temperature atomic forcemicroscope (AFM), we assess that in the cases of...the cantilever oscillation amplitude equals that induced by thermal noise given by ( ) w = ⎡ ⎣⎢ ⎤ ⎦⎥F k TkB Q 4 , 4min B 1 2 with Boltzmann’s...force is proportional to the local optical electricfield, while the thermal expansion/ absorption is due to resistive heating associatedwith electric

  19. Magnetic resonance force microscopy of paramagnetic electron spins at millikelvin temperatures.

    Science.gov (United States)

    Vinante, A; Wijts, G; Usenko, O; Schinkelshoek, L; Oosterkamp, T H

    2011-12-06

    Magnetic resonance force microscopy (MRFM) is a powerful technique to detect a small number of spins that relies on force detection by an ultrasoft magnetically tipped cantilever and selective magnetic resonance manipulation of the spins. MRFM would greatly benefit from ultralow temperature operation, because of lower thermomechanical noise and increased thermal spin polarization. Here we demonstrate MRFM operation at temperatures as low as 30 mK, thanks to a recently developed superconducting quantum interference device (SQUID)-based cantilever detection technique, which avoids cantilever overheating. In our experiment, we detect dangling bond paramagnetic centres on a silicon surface down to millikelvin temperatures. Fluctuations of such defects are supposedly linked to 1/f magnetic noise and decoherence in SQUIDs, as well as in several superconducting and single spin qubits. We find evidence that spin diffusion has a key role in the low-temperature spin dynamics.

  20. Optical pulling and pushing forces exerted on silicon nanospheres with strong coherent interaction between electric and magnetic resonances.

    Science.gov (United States)

    Liu, Hongfeng; Panmai, Mingcheng; Peng, Yuanyuan; Lan, Sheng

    2017-05-29

    We investigated theoretically and numerically the optical pulling and pushing forces acting on silicon (Si) nanospheres (NSs) with strong coherent interaction between electric and magnetic resonances. We examined the optical pulling and pushing forces exerted on Si NSs by two interfering waves and revealed the underlying physical mechanism from the viewpoint of electric- and magnetic-dipole manipulation. As compared with a polystyrene (PS) NS, it was found that the optical pulling force for a Si NS with the same size is enlarged by nearly two orders of magnitude. In addition to the optical pulling force appearing at the long-wavelength side of the magnetic dipole resonance, very large optical pushing force is observed at the magnetic quadrupole resonance. The correlation between the optical pulling/pushing force and the directional scattering characterized by the ratio of the forward to backward scattering was revealed. More interestingly, it was found that the high-order electric and magnetic resonances in large Si NSs play an important role in producing optical pulling force which can be generated by not only s-polarized wave but also p-polarized one. Our finding indicates that the strong coherent interaction between the electric and magnetic resonances existing in nanoparticles with large refractive indices can be exploited to manipulate the optical force acting on them and the correlation between the optical force and the directional scattering can be used as guidance. The engineering and manipulation of optical forces will find potential applications in the trapping, transport and sorting of nanoparticles.

  1. A Review on Resistive Switching in High-k Dielectrics: A Nanoscale Point of View Using Conductive Atomic Force Microscope

    Directory of Open Access Journals (Sweden)

    Mario Lanza

    2014-03-01

    Full Text Available Metal-Insulator-Metal (MIM structures have raised as the most promising configuration for next generation information storage, leading to great performance and fabrication-friendly Resistive Random Access Memories (RRAM. In these cells, the memory concept is no more based on the charge storage, but on tuning the electrical resistance of the insulating layer by applying electrical stresses to reach a high resistive state (HRS or “0” and a low resistive state (LRS or “1”, which makes the memory point. Some high-k dielectrics show this unusual property and in the last years high-k based RRAM have been extensively analyzed, especially at the device level. However, as resistance switching (in the most promising cells is a local phenomenon that takes place in areas of ~100 nm2, the use of characterization tools with high lateral spatial resolution is necessary. In this paper the status of resistive switching in high-k materials is reviewed from a nanoscale point of view by means of conductive atomic force microscope analyses.

  2. Using laser induced breakdown spectroscopy and acoustic radiation force elasticity microscope to measure the spatial distribution of corneal elasticity

    Science.gov (United States)

    Sun, Hui; Li, Xin; Fan, Zhongwei; Kurtz, Ron; Juhasz, Tibor

    2017-02-01

    Corneal biomechanics plays an important role in determining the eye's structural integrity, optical power and the overall quality of vision. It also plays an increasingly recognized role in corneal transplant and refractive surgery, affecting the predictability, quality and stability of final visual outcome [1]. A critical limitation to increasing our understanding of how corneal biomechanics controls corneal stability and refraction is the lack of non-invasive technologies that microscopically measure local biomechanical properties, such as corneal elasticity within the 3D space. Bubble based acoustic radiation force elastic microscopy (ARFEM) introduce the opportunity to measure the inhomogeneous elastic properties of the cornea by the movement of a micron size cavitation bubble generated by a low energy femtosecond laser pulse [2, 3]. Laser induced breakdown spectroscopy (LIBS) also known as laser induced plasma spectroscopy (LIPS) or laser spark spectrometry (LSS) is an atomic emission spectroscopy [4]. The LIBS principle of operation is quite simple, although the physical processes involved in the laser matter interaction are complex and still not completely understood. In one sentence for description, the laser pulses are focused down to a target so as to generate plasma that vaporizes a small amount of material which the emitted spectrum is measured to analysis the elements of the target.

  3. High-speed broadband nanomechanical property quantification and imaging of life science materials using atomic force microscope

    Science.gov (United States)

    Ren, Juan

    Nanoscale morphological characterization and mechanical properties quantification of soft and biological materials play an important role in areas ranging from nano-composite material synthesis and characterization, cellular mechanics to drug design. Frontier studies in these areas demand the coordination between nanoscale morphological evolution and mechanical behavior variations through simultaneous measurement of these two aspects of properties. Atomic force microscope (AFM) is very promising in achieving such simultaneous measurements at high-speed and broadband owing to its unique capability in applying force stimuli and then, measuring the response at specific locations in a physiologically friendly environment with pico-newton force and nanometer spatial resolution. Challenges, however, arise as current AFM systems are unable to account for the complex and coupled dynamics of the measurement system and probe-sample interaction during high-speed imaging and broadband measurements. In this dissertation, the creation of a set of dynamics and control tools to probe-based high-speed imaging and rapid broadband nanomechanical spectroscopy of soft and biological materials are presented. Firstly, advanced control-based approaches are presented to improve the imaging performance of AFM imaging both in air and in liquid. An adaptive contact mode (ACM) imaging scheme is proposed to replace the traditional contact mode (CM) imaging by addressing the major concerns in both the speed and the force exerted to the sample. In this work, the image distortion caused by the topography tracking error is accounted for in the topography quantification and the quantified sample topography is utilized in a gradient-based optimization method to adjust the cantilever deflection set-point for each scanline closely around the minimal level needed for maintaining a stable probe-sample contact, and a data-driven iterative feedforward control that utilizes a prediction of the next

  4. Role of attractive forces in tapping tip force microscopy

    DEFF Research Database (Denmark)

    Kyhle, Anders; Sørensen, Alexis Hammer; Bohr, Jakob

    1997-01-01

    We present experimental and numerical results demonstrating the drastic influence of attractive forces on the behaviour of the atomic force microscope when operated in the resonant tapping tip mode in an ambient environment. It is often assumed that tapping is related to repulsive interaction...

  5. Effects of the van der Waals Force on the Dynamics Performance for a Micro Resonant Pressure Sensor

    Directory of Open Access Journals (Sweden)

    Lizhong Xu

    2016-01-01

    Full Text Available The micro resonant pressure sensor outputs the frequency signals where the distortion does not take place in a long distance transmission. As the dimensions of the sensor decrease, the effects of the van der Waals forces should be considered. Here, a coupled dynamic model of the micro resonant pressure sensor is proposed and its coupled dynamic equation is given in which the van der Waals force is considered. By the equation, the effects of the van der Waals force on the natural frequencies and vibration amplitudes of the micro resonant pressure sensor are investigated. Results show that the natural frequency and the vibrating amplitudes of the micro resonant pressure sensor are affected significantly by van der Waals force for a small clearance between the film and the base plate, a small initial tension stress of the film, and some other conditions.

  6. A control approach to cross-coupling compensation of piezotube scanners in tapping-mode atomic force microscope imaging

    Science.gov (United States)

    Wu, Ying; Shi, Jian; Su, Chanmin; Zou, Qingze

    2009-04-01

    In this article, an approach based on the recently developed inversion-based iterative control (IIC) to cancel the cross-axis coupling effect of piezoelectric tube scanners (piezoscanners) in tapping-mode atomic force microscope (AFM) imaging is proposed. Cross-axis coupling effect generally exists in piezoscanners used for three-dimensional (x-y-z axes) nanopositioning in applications such as AFM, where the vertical z-axis movement can be generated by the lateral x-y axes scanning. Such x /y-to-z cross-coupling becomes pronounced when the scanning is at large range and/or at high speed. In AFM applications, the coupling-caused position errors, when large, can generate various adverse effects, including large imaging and topography distortions, and damage of the cantilever probe and/or the sample. This paper utilizes the IIC technique to obtain the control input to precisely track the coupling-caused x /y-to-z displacement (with sign-flipped). Then the obtained input is augmented as a feedforward control to the existing feedback control in tapping-mode imaging, resulting in the cancellation of the coupling effect. The proposed approach is illustrated through two exemplary applications in industry, the pole-tip recession examination, and the nanoasperity measurement on hard-disk drive. Experimental results show that the x /y-to-z coupling effect in large-range (20 and 45 μm) tapping-mode imaging at both low to high scan rates (2, 12.2 to 24.4 Hz) can be effectively removed.

  7. Pattern of Hydroxyapatite Crystal Growth on Bleached Enamel Following the Application of Two Antioxidants: An Atomic Force Microscope Study.

    Science.gov (United States)

    Bhusari, Chitra P; Sharma, Divya S

    This study observed the topographical pattern of hydroxyapatite deposition and growth (D&G) on bleached enamel following application of two antioxidants (sodium ascorbate and catalase) using atomic force microscope. Twenty enamel specimens (4×3×2mm), prepared from extracted impacted third molars, were mounted in self-cure acrylic and randomly grouped as: Group I-untreated; Group II- 35%H2O2; Group III- 35%H2O2 + artificial saliva; Group IV- 35%H2O2 + catalase+ artificial saliva; Group V- 35%H2O2 + sodium ascorbate+ artificial saliva. Groups I and II were observed immediately after treatment. Groups III-V were observed after 72 hrs. Roughness average was also calculated and analyzed with non-parametric Kruskall-Wallis ANOVA and Mann-Whitney tests. H2O2 dissolved matrix, exposed hydroxyapatite crystals (HACs), causing dissolution on the sides of and within HACs and opening up of nano-spaces. Artificial saliva showed growth of dissoluted crystals. Antioxidants+saliva showed potentiated remineralization by D&G on dissoluted HACs of bleached enamel. Catalase potentiated blockshaped, while sodium ascorbate the needle-shaped crystals with stair-pattern of crystallization. Evidence of oxygen bubbles was a new finding with catalase. Maximum roughness average was in group V followed by group II > group IV > group III > group I. Post-bleaching application of catalase and sodium ascorbate potentiated remineralization by saliva, but in different patterns. None of the tested antioxidant could return the original topography of enamel.

  8. Resonance oscillations of non-reciprocal long-range van der Waals forces between atoms in electromagnetic fields

    OpenAIRE

    Sherkunov, Yury

    2017-01-01

    We study theoretically the van der Waals interaction between two atoms out of equilibrium with isotropic electromagnetic field. We demonstrate that at large interatomic separations, the van der Waals forces are resonant, spatially oscillating and non-reciprocal due to resonance absorption and emission of virtual photons. We suggest that these forces can be used to manipulate and control centre-of-mass and relative motion of atomic pairs.

  9. Force-Detected Magnetic Resonance Imaging in Micron-Scale Liquids

    Science.gov (United States)

    Sixta, Aimee; Bogat, Sophia; Wright, Diego; Mozaffari, Shirin; Tennant, Daniel; Paster, Jeremy; Markert, John

    We report our efforts in the development of Nuclear Magnetic Resonance Force Microscopy (NMRFM) for the study of biological materials in liquid media at the micron scale. Our probe contains microfluidic samples sealed in thin-walled (few µm) quartz tubes, with a micro-oscillator sensor nearby in vacuum to maintain its high mechanical resonance quality factor. An initial demonstration utilizes a permalloy magnet on the oscillator tip, which provides a resonant slice of thickness 0.5 µm and an area of diameter 10µm these first measurements aim to demonstrate a single-shot measurement of the longitudinal relaxation time T1 in aqueous solutions of Cu2SO4. We also aim to implement a sawtooth 2? cyclic inversion of the nuclear spins, a detection scheme that effectively eliminates common measurement artifacts. At the micron scale, both spin diffusion and physical diffusion in liquids tend to blur images in conventional magnetic resonance imaging (MRI); we aim to exploit the local nature of the NMRFM probe to obtain higher resolution dynamical images, with the ultimate goal of imaging within individual biological cells.

  10. Formation and decay of resonance states in 9Be and 9B nuclei: Microscopic three-cluster model investigations

    Science.gov (United States)

    Vasilevsky, V. S.; Katō, K.; Takibayev, N. Zh.

    2017-09-01

    We study the nature of the low-lying resonance states in mirror nuclei 9Be and 9B. Investigations are performed within a three-cluster model. The model makes use of the hyperspherical harmonics, which provides a convenient description of the three-cluster continuum. The dominant three-cluster configurations α +α +n and α +α +p in 9Be and 9B, respectively, are taken into account. Dominant decay channels for all resonance states in 9Be and 9B are explored. Much attention is paid to the controversial 1 /2+ resonance states in both nuclei. We study effects of the Coulomb interaction on the energy and width of three-cluster resonances in the mirror nuclei 9Be and 9B. We also search for the Hoyle-analog state, which is a key step for alternative ways to synthesize 9Be and 9B in triple collisions of clusters in a stellar environment.

  11. Application of magnetic resonance force microscopy cyclic adiabatic inversion for a single-spin measurement

    CERN Document Server

    Berman, G P; Chapline, G; Gurvitz, S A; Hammel, P C; Pelekhov, D V; Suter, A; Tsifrinovich, V I

    2003-01-01

    We consider the process of a single-spin measurement using magnetic resonance force microscopy (MRFM) with a cyclic adiabatic inversion (CAI). This technique is also important for different applications, including a measurement of a qubit state in quantum computation. The measurement takes place through the interaction of a single spin with a cantilever modelled by a quantum oscillator in a coherent state in a quasi-classical range of parameters. The entire system is treated rigorously within the framework of the Schroedinger equation. For a many-spin system our equations accurately describe conventional MRFM experiments involving CAI of the spin system. Our computer simulations of the quantum spin-cantilever dynamics show that the probability distribution for the cantilever position develops two asymmetric peaks with the total relative probabilities mainly dependent on the initial angle between the directions of the average spin and the effective magnetic field, in the rotating frame. We show that each of th...

  12. Dislocation dynamics in Al-Mg-Zn alloys : A nuclear magnetic resonance and transmission electron microscopic study

    NARCIS (Netherlands)

    Hosson, J.Th.M. De; Kanert, O.; Schlagowski, U.; Boom, G.

    1988-01-01

    Pulsed nuclear magnetic resonance (NMR) proved to be a complementary new technique for the study of moving dislocations in Al-Mg-Zn alloys. The NMR technique, in combination with transmission electron microscopy (TEM), has been applied to study dislocation motion in Al-0.6 at. % Mg-1 at. % Zn and

  13. Tetraquark bound states and resonances in a unitary microscopic quark model: A case study of bound states of two light quarks and two heavy antiquarks

    Science.gov (United States)

    Bicudo, P.; Cardoso, M.

    2016-11-01

    We address q q Q ¯Q ¯ exotic tetraquark bound states and resonances with a fully unitarized and microscopic quark model. We propose a triple string flip-flop potential, inspired by lattice QCD tetraquark static potentials and flux tubes, combining meson-meson and double Y potentials. Our model includes the color excited potential, but neglects the spin-tensor potentials, as well as all the other relativistic effects. To search for bound states and resonances, we first solve the two-body mesonic problem. Then we develop fully unitary techniques to address the four-body tetraquark problem. We fold the four-body Schrödinger equation with the mesonic wave functions, transforming it into a two-body meson-meson problem with nonlocal potentials. We find bound states for some quark masses, including the one reported in lattice QCD. Moreover, we also find resonances and calculate their masses and widths, by computing the T matrix and finding its pole positions in the complex energy plane, for some quantum numbers. However, a detailed analysis of the quantum numbers where binding exists shows a discrepancy with recent lattice QCD results for the l l b ¯ b ¯ tetraquark bound states. We conclude that the string flip-flop models need further improvement.

  14. Recent Advances of MEMS Resonators for Lorentz Force Based Magnetic Field Sensors: Design, Applications and Challenges

    Directory of Open Access Journals (Sweden)

    Agustín Leobardo Herrera-May

    2016-08-01

    Full Text Available Microelectromechanical systems (MEMS resonators have allowed the development of magnetic field sensors with potential applications such as biomedicine, automotive industry, navigation systems, space satellites, telecommunications and non-destructive testing. We present a review of recent magnetic field sensors based on MEMS resonators, which operate with Lorentz force. These sensors have a compact structure, wide measurement range, low energy consumption, high sensitivity and suitable performance. The design methodology, simulation tools, damping sources, sensing techniques and future applications of magnetic field sensors are discussed. The design process is fundamental in achieving correct selection of the operation principle, sensing technique, materials, fabrication process and readout systems of the sensors. In addition, the description of the main sensing systems and challenges of the MEMS sensors are discussed. To develop the best devices, researches of their mechanical reliability, vacuum packaging, design optimization and temperature compensation circuits are needed. Future applications will require multifunctional sensors for monitoring several physical parameters (e.g., magnetic field, acceleration, angular ratio, humidity, temperature and gases.

  15. Electron transport in dodecylamine capped gold nanocluster films using current sensing atomic force microscope (C-AFM).

    Science.gov (United States)

    Chaudhary, Minakshi; Dey, Shirshendu; Date, Kalyani; Iyyer, S B; Dharmadhikaril, C V

    2009-09-01

    Electron transport across cataphoretically deposited dodecylamine capped gold nanocluster rough films on Si(111) substrate is investigated using current sensing atomic force microscopy. Contact mode images depict uniform deposition of agglomerates of gold nanoparticles. The current images display strong correlation with topographic images. The I-V measurement on a single agglomerate of approximately = 250 nm size at different forces exhibits force dependent threshold voltage. The electron transport from tip to sample is found to be ohmic in contrast to that from sample to tip which, exhibits Fowler-Nordheim behavior up to 35 nN force. At higher forces, the I-V behavior could be attributed to other electron transfer processes such as Schottky/Poole-Frenkel or trapping/detrapping, although no exact mechanism could be identified. The results are discussed in the light of models based on Coulomb blockaded collective charge transport in nanoparticle arrays duly accounting for the potential role of the capping layer.

  16. Left and right ventricular hemodynamic forces in healthy volunteers and elite athletes assessed with 4D flow magnetic resonance imaging.

    Science.gov (United States)

    Arvidsson, Per M; Töger, Johannes; Carlsson, Marcus; Steding-Ehrenborg, Katarina; Pedrizzetti, Gianni; Heiberg, Einar; Arheden, Håkan

    2017-02-01

    Intracardiac blood flow is driven by hemodynamic forces that are exchanged between the blood and myocardium. Previous studies have been limited to 2D measurements or investigated only left ventricular (LV) forces. Right ventricular (RV) forces and their mechanistic contribution to asymmetric redirection of flow in the RV have not been measured. We therefore aimed to quantify 3D hemodynamic forces in both ventricles in a cohort of healthy subjects, using magnetic resonance imaging 4D flow measurements. Twenty five controls, 14 elite endurance athletes, and 2 patients with LV dyssynchrony were included. 4D flow data were used as input for the Navier-Stokes equations to compute hemodynamic forces over the entire cardiac cycle. Hemodynamic forces were found in a qualitatively consistent pattern in all healthy subjects, with variations in amplitude. LV forces were mainly aligned along the apical-basal longitudinal axis, with an additional component aimed toward the aortic valve during systole. Conversely, RV forces were found in both longitudinal and short-axis planes, with a systolic force component driving a slingshot-like acceleration that explains the mechanism behind the redirection of blood flow toward the pulmonary valve. No differences were found between controls and athletes when indexing forces to ventricular volumes, indicating that cardiac force expenditures are tuned to accelerate blood similarly in small and large hearts. Patients' forces differed from controls in both timing and amplitude. Normal cardiac pumping is associated with specific force patterns for both ventricles, and deviation from these forces may be a sensitive marker of ventricular dysfunction. Reference values are provided for future studies.NEW & NOTEWORTHY Biventricular hemodynamic forces were quantified for the first time in healthy controls and elite athletes (n = 39). Hemodynamic forces constitute a slingshot-like mechanism in the right ventricle, redirecting blood flow toward the

  17. Analyzing the effect of the forces exerted on cantilever probe tip of atomic force microscope with tapering-shaped geometry and double piezoelectric extended layers in the air and liquid environments

    Science.gov (United States)

    Korayem, Moharam Habibnejad; Nahavandi, Amir

    2017-01-01

    The aim of the present study is to assess the force vibrational performance of tapering-shaped cantilevers, using Euler-Bernoulli theory. Tapering-shaped cantilevers have plan-view geometry consisting of a rectangular section at the clamped end and a triangular section at the tip. Hamilton's principle is utilized to obtain the partial differential equations governing the nonlinear vibration of the system as well as the corresponding boundary conditions. In this model, a micro cantilever, which is covered by two piezoelectric layers at the top and the bottom, is modeled at angle α. Both of these layers are subjected to similar AC and DC voltages. This paper attempts to determine the effect of the capillary force exerted on the cantilever probe tip of an atomic force microscope. The capillary force emerges due to the contact between thin water films with a thickness of hc which have accumulated on the sample and the probe. In addition, an attempt is made to develop the capillary force between the tip and the sample surface with respect to the geometry obtained. The smoothness or the roughness of the surfaces as well as the geometry of the cantilever tip have significant effects on the modeling of forces applied to the probe tip. In this article, the Van der Waals and the repulsive forces are considered to be the same in all of the simulations, and only is the capillary force altered in order to evaluate the role of this force in the atomic force microscope based modeling. We also indicate that the tip shape and the radial distance of the meniscus greatly influence the capillary force. The other objective of our study is to draw a comparison between tapering-and rectangular-shaped cantilevers. Furthermore, the equation for converting the tip of a tapering-shaped cantilever into a rectangular cantilever is provided. Moreover, the modal analysis method is employed to solve the motion equation. The mode shape function for the two tapering-shaped sections of the first

  18. Acquisition of a Surface Plasmon Resonance Imager, Digital Microscope, and Peristaltic Pumps for Defense-Based Research

    Science.gov (United States)

    2016-05-05

    small power sources to operate them. We have been developing microfluidic formate, methanol , and hydrogen fuel cells (FCs). The use of these... fuels entails one of the most promising mobile technologies by which such power can be provided. FCs can be considered chemical reactors designed to...SECURITY CLASSIFICATION OF: The goal of this proposal is to purchase the GWC Technologies , Inc. Horizontal Surface Plasmon Resonance Imaging (SPRi

  19. The relationship between local liquid density and force applied on a tip of atomic force microscope: a theoretical analysis for simple liquids.

    Science.gov (United States)

    Amano, Ken-ichi; Suzuki, Kazuhiro; Fukuma, Takeshi; Takahashi, Ohgi; Onishi, Hiroshi

    2013-12-14

    The density of a liquid is not uniform when placed on a solid. The structured liquid pushes or pulls a probe employed in atomic force microscopy, as demonstrated in a number of experimental studies. In the present study, the relation between the force on a probe and the local density of a liquid is derived based on the statistical mechanics of simple liquids. When the probe is identical to a solvent molecule, the strength of the force is shown to be proportional to the vertical gradient of ln(ρDS) with the local liquid's density on a solid surface being ρDS. The intrinsic liquid's density on a solid is numerically calculated and compared with the density reconstructed from the force on a probe that is identical or not identical to the solvent molecule.

  20. A microscopic model beyond mean-field: from giant resonances properties to the fit of new effective interactions

    Directory of Open Access Journals (Sweden)

    Brenna M.

    2014-03-01

    Full Text Available A completely microscopic beyond mean-field approach has been elaborated to overcome some intrinsic limitations of self-consistent mean-field schemes applied to nuclear systems, such as the incapability to produce some properties of single-particle states (e.g. spectroscopic factors, as well as of collective states (e.g. their damping width and their gamma decay to the ground state or to low lying states. Since commonly used effective interactions are fitted at the mean-field level, one should aim at refitting them including the desired beyond mean-field contributions in the refitting procedure. If zero-range interactions are used, divergences arise. We present some steps towards the refitting of Skyrme interactions, for its application in finite nuclei.

  1. Resonance properties of a closed rotating rectangular basin subject to space- and time-dependent wind forcing

    NARCIS (Netherlands)

    Chen, Wenlong; Roos, Pieter C.; Schuttelaars, H.M.; Hulscher, Suzanne J.M.H.

    2015-01-01

    We present an idealised process-based model to study the possibly resonant response of closed basins subject to periodic wind forcing. Two solution methods are adopted: a collocation technique (valid for arbitrary rotation) and an analytical expansion (assuming weak rotation). The spectral response,

  2. The Van der Waals-force-induced phononic band gap and resonant scattering in two-nanosphere aggregate

    Energy Technology Data Exchange (ETDEWEB)

    Wu Jiuhui, E-mail: ejhwu@mail.xjtu.edu.cn; Zhang Siwen, E-mail: sunnywell@stu.xjtu.edu.cn [Xi' an Jiaotong University, School of Mechanical Engineering (China); Zhou Kejiang, E-mail: ekjzhou@zju.edu.cn [Zhejiang University, College of Information Science and Engineering (China)

    2012-10-15

    A physical mechanism of phononic band gap and resonant nanoacoustic scattering in an aggregate of two elastic nanospheres is presented in this paper. By considering the Van der Waals (VdW) force between two nanospheres illuminated by nanoacoustic wave, phononic band gap and frequency shift at the lower frequency side, and largely enhanced nanoacoustic scattering at the other frequency range have been found through calculating the form function of the acoustic scattering from the nanosystem. This VdW-force-induced band gap is different from the known mechanisms of Bragg scattering and local resonances for periodic media. It is shown that when the separation distance between two nanospheres is decreasing from 20 to 1 nm, due to the increasing VdW force, the nanoacoustic scattering is much heightened by two order of magnitude, and meanwhile the frequency shift and phononic band gap at the low frequencies are both widened. These results could provide potential applications of nanoacoustic devices.

  3. Microscopic insight into role of protein flexibility during ion exchange chromatography by nuclear magnetic resonance and quartz crystal microbalance approaches.

    Science.gov (United States)

    Hao, Dongxia; Ge, Jia; Huang, Yongdong; Zhao, Lan; Ma, Guanghui; Su, Zhiguo

    2016-03-18

    Driven by the prevalent use of ion exchange chromatography (IEC) for polishing therapeutic proteins, many rules have been formulated to summarize the different dependencies between chromatographic data and various operational parameters of interest based on statically determined interactions. However, the effects of the unfolding of protein structures and conformational stability are not as well understood. This study focuses on how the flexibility of proteins perturbs retention behavior at the molecular scale using microscopic characterization approaches, including hydrogen-deuterium (H/D) exchange detected by NMR and a quartz crystal microbalance (QCM). The results showed that a series of chromatographic retention parameters depended significantly on the adiabatic compressibility and structural flexibility of the protein. That is, softer proteins with higher flexibility tended to have longer retention times and stronger affinities on SP Sepharose adsorbents. Tracing the underlying molecular mechanism using NMR and QCM indicated that an easily unfolded flexible protein with a more compact adsorption layer might contribute to the longer retention time on adsorbents. The use of NMR and QCM provided a previously unreported approach for elucidating the effect of protein structural flexibility on binding in IEC systems. Copyright © 2016. Published by Elsevier B.V.

  4. Elastic-properties measurement at high temperatures through contact resonance atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Marinello, Francesco, E-mail: francesco.marinello@unipd.it; Pezzuolo, Andrea; Sartori, Luigi; Cavalli, Raffaele [University of Padova, Department of Land, Environment, Agriculture and Forestry, Viale dell’Università 16, 35020 Legnaro, Padova (Italy); Carmignato, Simone [University of Padova, Department of Management and Engineering, Stradella San Nicola 3, 36100 Vicenza (Italy); Savio, Enrico [University of Padova, Department of Industrial Engineering, Via Venezia 1, 35131 Padova (Italy); De Chiffre, Leonardo [Technical University of Denmark, Department of Mechanical Engineering, Produktionstorvet 425, 2800 Kgs. Lyngby (Denmark)

    2015-06-23

    Miniaturization of products and need for further improvement of machines performance introduce new serious challenges in materials characterization. In particular non-destructive mechanical testing in the sub-micrometer scale is needed to better understand and improve micro-manufacturing operations. To this regard, some open issues are of particular interest: low depth of penetration, high lateral resolution and measurements at elevated temperatures. An interesting solution is given by acoustic microscopy techniques, which can be successfully implemented for advanced research in surface elasticity, allowing fast direct and non-destructive measurement of Young’s modulus and related surface parameters. In this work an instrument set up for Contact Resonance Atomic Force Microscopy is proposed, where the sample with is coupled to a heating stage and a piezoelectric transducer directly vibrate the cantilever during scanning, in order to allow exploitation of high resolution measurements at relatively high temperatures. Such instrument set up was undergone a set of calibration experiments in order to allow not only qualitative but also quantitative characterization of surfaces. The work was completed with a feasibility study with mechanical and topography measurements at temperatures as high as 150°C, with lateral resolution lower than 100 nm.

  5. Application of atomic force microscopy and ultrasonic resonator technology on nanoscale: distinction of nanoemulsions from nanocapsules.

    Science.gov (United States)

    Preetz, Claudia; Hauser, Anton; Hause, Gerd; Kramer, Armin; Mäder, Karsten

    2010-01-31

    Oily core nanocapsules were prepared by sequential addition of positively and negatively charged polyelectrolytes based on a nanoemulsion and transformation thereof into a core-shell structure. The capsules were well characterized by photon correlation spectroscopy, laser diffraction, zeta-potential and transmission electron microscopy and feature an average size of 150nm and a negative surface charge. The aim of the current study was to improve the dispersion stability and mechanic rigidity of the capsule wall by depositing an increasing number of up to five layers. Therefore, atomic force microscopy (AFM) and ultrasonic resonator technology (URT) were applied to investigate the shell of the nanoemulsion, the intermediate and final nanocapsules in more detail. AFM was performed to investigate the shape, morphology and mechanic properties of the emulsion and capsule shell. It proved to be a feasible technique to distinguish nanoemulsions from nanocapsules by stiffness analysis. URT was utilized in order to observe the ultrasound velocity and could confirm the AFM results. Both techniques demonstrated that the shell around an oil droplet solidified with increasing number of polyelectrolyte layers. Since a solid wall might have the potential of a strong diffusion barrier, nanocapsules might present a feasible prolonged release drug delivery system in contrast to nanoemulsions. Copyright 2009 Elsevier B.V. All rights reserved.

  6. Elastic-properties measurement at high temperatures through contact resonance atomic force microscopy

    Science.gov (United States)

    Marinello, Francesco; Pezzuolo, Andrea; Carmignato, Simone; Savio, Enrico; De Chiffre, Leonardo; Sartori, Luigi; Cavalli, Raffaele

    2015-06-01

    Miniaturization of products and need for further improvement of machines performance introduce new serious challenges in materials characterization. In particular non-destructive mechanical testing in the sub-micrometer scale is needed to better understand and improve micro-manufacturing operations. To this regard, some open issues are of particular interest: low depth of penetration, high lateral resolution and measurements at elevated temperatures. An interesting solution is given by acoustic microscopy techniques, which can be successfully implemented for advanced research in surface elasticity, allowing fast direct and non-destructive measurement of Young's modulus and related surface parameters. In this work an instrument set up for Contact Resonance Atomic Force Microscopy is proposed, where the sample with is coupled to a heating stage and a piezoelectric transducer directly vibrate the cantilever during scanning, in order to allow exploitation of high resolution measurements at relatively high temperatures. Such instrument set up was undergone a set of calibration experiments in order to allow not only qualitative but also quantitative characterization of surfaces. The work was completed with a feasibility study with mechanical and topography measurements at temperatures as high as 150°C, with lateral resolution lower than 100 nm.

  7. MDM2-MDM4 molecular interaction investigated by atomic force spectroscopy and surface plasmon resonance.

    Science.gov (United States)

    Moscetti, Ilaria; Teveroni, Emanuela; Moretti, Fabiola; Bizzarri, Anna Rita; Cannistraro, Salvatore

    Murine double minute 2 (MDM2) and 4 (MDM4) are known as the main negative regulators of p53, a tumor suppressor. They are able to form heterodimers that are much more effective in the downregulation of p53. Therefore, the MDM2-MDM4 complex could be a target for promising therapeutic restoration of p53 function. To this aim, a deeper understanding of the molecular mechanisms underlining the heterodimerization is needed. The kinetic and thermodynamic characterization of the MDM2-MDM4 complex was performed with two complementary approaches: atomic force spectroscopy and surface plasmon resonance. Both techniques revealed an equilibrium dissociation constant (KD ) in the micromolar range for the MDM2-MDM4 heterodimer, similar to related complexes involved in the p53 network. Furthermore, the MDM2-MDM4 complex is characterized by a relatively high free energy, through a single energy barrier, and by a lifetime in the order of tens of seconds. New insights into the MDM2-MDM4 interaction could be highly important for developing innovative anticancer drugs focused on p53 reactivation.

  8. Development of atomic force microscope with wide-band magnetic excitation for study of soft matter dynamics.

    Science.gov (United States)

    Kageshima, Masami; Chikamoto, Takuma; Ogawa, Tatsuya; Hirata, Yoshiki; Inoue, Takahito; Naitoh, Yoshitaka; Li, Yan Jun; Sugawara, Yasuhiro

    2009-02-01

    In order to probe dynamical properties of mesoscopic soft matter systems such as polymers, structured liquid, etc., a new atomic force microscopy apparatus with a wide-band magnetic cantilever excitation system was developed. Constant-current driving of an electromagnet up to 1 MHz was implemented with a closed-loop driver circuit. Transfer function of a commercial cantilever attached with a magnetic particle was measured in a frequency range of 1-1000 kHz in distilled water. Effects of the laser spot position, distribution of the force exerted on the cantilever, and difference in the detection scheme on the obtained transfer function are discussed in comparison with theoretical predictions by other research groups. A preliminary result of viscoelasticity spectrum measurement of a single dextran chain is shown and is compared with a recent theoretical calculation.

  9. Optically-controlled extinction ratio and Q-factor tunable silicon microring resonators based on optical forces

    Science.gov (United States)

    Long, Yun; Wang, Jian

    2014-06-01

    Tunability is a desirable property of microring resonators to facilitate superior performance. Using light to control light, we present an alternative simple approach to tuning the extinction ratio (ER) and Q-factor of silicon microring resonators based on optical forces. We design an opto-mechanical tunable silicon microring resonator consisting of an add-drop microring resonator and a control-light-carrying waveguide (``controlling'' waveguide). One of the two bus waveguides of the microring resonator is a deformable nanostring put in parallel with the ``controlling'' waveguide. The tuning mechanism relies on the optical force induced deflection of suspended nanostring, leading to the change of coupling coefficient of microring and resultant tuning of ER and Q-factor. Two possible geometries, i.e. double-clamped nanostring and cantilever nanostring, are studied in detail for comparison. The obtained results imply a favorable structure with the microring positioned at the end of the cantilever nanostring. It features a wide tuning range of ER from 5.6 to 39.9 dB and Q-factor from 309 to 639 as changing the control power from 0 to 1.4 mW.

  10. An Atomic Force Microscope Study Revealed Two Mechanisms in the Effect of Anticancer Drugs on Rate-Dependent Young's Modulus of Human Prostate Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Juan Ren

    Full Text Available Mechanical properties of cells have been recognized as a biomarker for cellular cytoskeletal organization. As chemical treatments lead to cell cytoskeletal rearrangements, thereby, modifications of cellular mechanical properties, investigating cellular mechanical property variations provides insightful knowledge to effects of chemical treatments on cancer cells. In this study, the effects of eight different anticancer drugs on the mechanical properties of human prostate cancer cell (PC-3 are investigated using a recently developed control-based nanoindentation measurement (CNM protocol on atomic force microscope (AFM. The CNM protocol overcomes the limits of other existing methods to in-liquid nanoindentation measurement of live cells on AFM, particularly for measuring mechanical properties of live cells. The Young's modulus of PC-3 cells treated by the eight drugs was measured by varying force loading rates over three orders of magnitude, and compared to the values of the control. The results showed that the Young's modulus of the PC-3 cells increased substantially by the eight drugs tested, and became much more pronounced as the force load rate increased. Moreover, two distinct trends were clearly expressed, where under the treatment of Disulfiram, paclitaxel, and MK-2206, the exponent coefficient of the frequency- modulus function remained almost unchanged, while with Celebrex, BAY, Totamine, TPA, and Vaproic acid, the exponential rate was significantly increased.

  11. Nanoscale infrared (IR) spectroscopy and imaging of structural lipids in human stratum corneum using an atomic force microscope to directly detect absorbed light from a tunable IR laser source.

    Science.gov (United States)

    Marcott, Curtis; Lo, Michael; Kjoller, Kevin; Domanov, Yegor; Balooch, Guive; Luengo, Gustavo S

    2013-06-01

    An atomic force microscope (AFM) and a tunable infrared (IR) laser source have been combined in a single instrument (AFM-IR) capable of producing ~200-nm spatial resolution IR spectra and absorption images. This new capability enables IR spectroscopic characterization of human stratum corneum at unprecendented levels. Samples of normal and delipidized stratum corneum were embedded, cross-sectioned and mounted on ZnSe prisms. A pulsed tunable IR laser source produces thermomechanical expansion upon absorption, which is detected through excitation of contact resonance modes in the AFM cantilever. In addition to reducing the total lipid content, the delipidization process damages the stratum corneum morphological structure. The delipidized stratum corneum shows substantially less long-chain CH2 -stretching IR absorption band intensity than normal skin. AFM-IR images that compare absorbances at 2930/cm (lipid) and 3290/cm (keratin) suggest that regions of higher lipid concentration are located at the perimeter of corneocytes in the normal stratum corneum. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Human developmental anatomy: microscopic magnetic resonance imaging (μMRI) of four human embryos (from Carnegie Stage 10 to 20).

    Science.gov (United States)

    Lhuaire, Martin; Martinez, Agathe; Kaplan, Hervé; Nuzillard, Jean-Marc; Renard, Yohann; Tonnelet, Romain; Braun, Marc; Avisse, Claude; Labrousse, Marc

    2014-12-01

    Technological advances in the field of biological imaging now allow multi-modal studies of human embryo anatomy. The aim of this study was to assess the high magnetic field μMRI feasibility in the study of small human embryos (less than 21mm crown-rump) as a new tool for the study of human descriptive embryology and to determine better sequence characteristics to obtain higher spatial resolution and higher signal/noise ratio. Morphological study of four human embryos belonging to the historical collection of the Department of Anatomy in the Faculty of Medicine of Reims was undertaken by μMRI. These embryos had, successively, crown-rump lengths of 3mm (Carnegie Stage, CS 10), 12mm (CS 16), 17mm (CS 18) and 21mm (CS 20). Acquisition of images was performed using a vertical nuclear magnetic resonance spectrometer, a Bruker Avance III, 500MHz, 11.7T equipped for imaging. All images were acquired using 2D (transverse, sagittal and coronal) and 3D sequences, either T1-weighted or T2-weighted. Spatial resolution between 24 and 70μm/pixel allowed clear visualization of all anatomical structures of the embryos. The study of human embryos μMRI has already been reported in the literature and a few atlases exist for educational purposes. However, to our knowledge, descriptive or morphological studies of human developmental anatomy based on data collected these few μMRI studies of human embryos are rare. This morphological noninvasive imaging method coupled with other techniques already reported seems to offer new perspectives to descriptive studies of human embryology.

  13. Interaction between Yarkovsky force and mean-motion resonances: Some specific properties

    Directory of Open Access Journals (Sweden)

    Milić-Žitnik I.

    2016-01-01

    Full Text Available Recently, we analyzed the role of mean-motion resonances in semi-major axis mobility of asteroids, and established a functional relationship that describes the dependence of the average time spent inside the resonance on the strength of this resonance and the semi-major axis drift speed. Here we extend this analyzis in two directions. First, we study the distribution of time delays inside the resonance and found that it could be described by the modified Laplace asymmetric distribution. Second, we analyze how the time spent inside the resonance depends on orbital eccentricity, and propose a relation that allows to take into account this parameter as well.

  14. Resonance

    DEFF Research Database (Denmark)

    Petersen, Nils Holger

    2014-01-01

    A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice.......A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice....

  15. Formation and characterization of thin films from phthalocyanine complexes: An electrosynthesis study using the atomic-force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Vergara, M.E. [Departamento de Ingenieria Mecatronica, Escuela de Ingenieria, Universidad Anahuac del Norte, Avenida Lomas de la Anahuac s/n, Col. Lomas Anahuac, 52786, Huixquilucan (Mexico)]. E-mail: elena.sanchez@anahuac.mx; Islas Bernal, I.F. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, 04510, Mexico D.F. (Mexico); Rivera, M. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, 04510, Mexico D.F. (Mexico); Ortiz Rebollo, A. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, A.P. 70-360, Coyoacan, 04510, Mexico, D.F. (Mexico); Alvarez Bada, J.R. [Instituto Tecnologico y de Estudios Superiores de Monterrey, Campus Ciudad de Mexico, Calle del Puente 222, Col. Ejidos de Huipulco, 14380, Mexico D.F. (Mexico)

    2007-05-07

    ({mu}-Cyano)(phthalocyaninato)metal(III) [PcMCN]{sub n} species with a central transition metal ion, such as Fe(III) and Co(III), were used to prepare molecular films on a highly oriented pyrolytic graphite electrode substrate by using the cyclic voltammetry technique. In order to investigate the influence of the ligand on the film properties, 1,8-dihydroxyanthraquinone and 2,6-dihydroxyanthraquinone as bivalent ligands were employed. The structure of the molecular materials was analyzed by infrared spectroscopy. The in situ film formation, texture, composition and conductivity of each film were further investigated using atomic force microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and the four-probe technique, respectively. The [PcMCN]{sub n} complexes provided conductive films with an electrical conductivity of 1 x 10{sup -6} {omega}{sup -1} cm{sup -1} at 298 K.

  16. Determination of corner positions for calculation of step height of atomic force microscope images based on ISO 5436-1.

    Science.gov (United States)

    Adebayo, Adedayo S; Xuezeng, Zhao; Weijie, Wang

    2013-06-01

    Step height is defined as the vertical spacing between two plane-parallel planes comprising an elevation or an indentation and the substrate. In atomic force microscopy (AFM), there are many algorithms for determining feature dimensions such as step height and width. One common problem of many algorithms is the difficulty for users to accurately determine the corner positions needed to properly implement the said algorithms. A new algorithm based on ISO 5436-1 is proposed that determines the necessary corner positions along with two examples illustrating the implementation of this algorithm. We propose calling this new method the determinant method. Since the corner positions are automatically decided, feature dimensions such as step height of an AFM image are easily determined. Comparative experiments carried out to compare the step height measurement using this algorithm and the SPIP software from Image Metrology show encouraging results.

  17. Direct method for magnetostriction coefficient measurement based on atomic force microscope, illustrated by the example of Tb–Co film

    Energy Technology Data Exchange (ETDEWEB)

    Lima, B.L.S. [Laboratório de Sensores Óticos, Escola Politécnica, Universidade de São Paulo, SP (Brazil); Maximino, F.L. [Laboratório de Materiais Magnéticos, Instituto de Física, Universidade de São Paulo, CEP:05314-970 São Paulo, SP (Brazil); Santos, J.C. [Laboratório de Sensores Óticos, Escola Politécnica, Universidade de São Paulo, SP (Brazil); Santos, A.D., E-mail: adsantos@if.usp.br [Laboratório de Materiais Magnéticos, Instituto de Física, Universidade de São Paulo, CEP:05314-970 São Paulo, SP (Brazil)

    2015-12-01

    This paper presents a method based on the Atomic Force Microscopy technique for direct measurement of magnetostriction coefficient of amorphous Tb–Co films deposited on Si(100) substrate. The magnetostriction coefficient of the film is determined by AFM measuring the deflection of the sample when applying a magnetic field. In order to maximize the deflection of the sample, in-plane magnetic anisotropy was induced by heat treatment under a magnetic field of 5 kOe. The value obtained for the saturation magnetostriction is 204×10{sup −6} for the Tb{sub 23}Co{sub 77} film. - Highlights: • Measurement of magnetostriction coefficient using AFM. • Tb–Co thin films produced by magnetron sputtering. • Magnetostriction characterization of magnetic thin films on nonmagnetic substrates.

  18. Design and control of multi-actuated atomic force microscope for large-range and high-speed imaging

    Energy Technology Data Exchange (ETDEWEB)

    Soltani Bozchalooi, I.; Careaga Houck, A. [Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); AlGhamdi, J. [Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Department of Chemistry, College of Science, University of Dammam, Dammam (Saudi Arabia); Youcef-Toumi, K. [Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2016-01-15

    This paper presents the design and control of a high-speed and large-range atomic force microscopy (AFM). A multi-actuation scheme is proposed where several nano-positioners cooperate to achieve the range and speed requirements. A simple data-based control design methodology is presented to effectively operate the AFM scanner components. The proposed controllers compensate for the coupled dynamics and divide the positioning responsibilities between the scanner components. As a result, the multi-actuated scanner behavior is equivalent to that of a single X–Y–Z positioner with large range and high speed. The scanner of the designed AFM is composed of five nano-positioners, features 6 μm out-of-plane and 120 μm lateral ranges and is capable of high-speed operation. The presented AFM has a modular design with laser spot size of 3.5 μm suitable for small cantilever, an optical view of the sample and probe, a conveniently large waterproof sample stage and a 20 MHz data throughput for high resolution image acquisition at high imaging speeds. This AFM is used to visualize etching of calcite in a solution of sulfuric acid. Layer-by-layer dissolution and pit formation along the crystalline lines in a low pH environment is observed in real time. - Highlights: • High-speed AFM imaging is extended to large lateral and vertical scan ranges. • A general multi-actuation approach to atomic force microscopy is presented. • A high-speed AFM is designed and implemented based on the proposed method. • Multi-actuator control is designed auxiliary to a PID unit to maintain flexibility. • Influence of calcite crystal structure on dissolution is visualized in video form.

  19. Torsional resonance mode magnetic force microscopy: enabling higher lateral resolution magnetic imaging without topography-related effects.

    Science.gov (United States)

    Kaidatzis, A; García-Martín, J M

    2013-04-26

    We present experimental work that reveals the benefits of performing magnetic force microscopy measurements employing the torsional resonance mode of cantilever oscillation. This approach provides two clear advantages: the ability of performing magnetic imaging without topography-related interference and the significant lateral resolution improvement (approximately 15%). We believe that this work demonstrates a significant improvement to a versatile magnetic imaging technique widely used in academia and in industry.

  20. Resonances

    DEFF Research Database (Denmark)

    an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...... theoretical consciousness through historical narrative ‘in practice’, by discussing selected historical topics from Western cultural history, within the disciplines of history, literature, visual arts, musicology, archaeology, philosophy, and theology. The title Resonances indicates the overall perspective...... of the book: how connotations of past meanings may resonate through time, in new contexts, assuming new meanings without surrendering the old....

  1. Force

    CERN Document Server

    Graybill, George

    2007-01-01

    Forces are at work all around us. Discover what a force is, and different kinds of forces that work on contact and at a distance. We use simple language and vocabulary to make this invisible world easy for students to ""see"" and understand. Examine how forces ""add up"" to create the total force on an object, and reinforce concepts and extend learning with sample problems.

  2. Standardized cardiovascular magnetic resonance imaging (CMR protocols, society for cardiovascular magnetic resonance: board of trustees task force on standardized protocols

    Directory of Open Access Journals (Sweden)

    Kim Raymond J

    2008-07-01

    Full Text Available Index 1. General techniques 1.1. Stress and safety equipment 1.2. Left ventricular (LV structure and function module 1.3. Right ventricular (RV structure and function module 1.4. Gadolinium dosing module. 1.5. First pass perfusion 1.6. Late gadolinium enhancement (LGE 2. Disease specific protocols 2.1. Ischemic heart disease 2.1.1. Acute myocardial infarction (MI 2.1.2. Chronic ischemic heart disease and viability 2.1.3. Dobutamine stress 2.1.4. Adenosine stress perfusion 2.2. Angiography: 2.2.1. Peripheral magnetic resonance angiography (MRA 2.2.2. Thoracic MRA 2.2.3. Anomalous coronary arteries 2.2.4. Pulmonary vein evaluation 2.3. Other 2.3.1. Non-ischemic cardiomyopathy 2.3.2. Arrhythmogenic right ventricular cardiomyopathy (ARVC 2.3.3. Congenital heart disease 2.3.4. Valvular heart disease 2.3.5. Pericardial disease 2.3.6. Masses

  3. Tetraquark bound states and resonances in the unitary and microscopic triple string flip-flop quark model, the light-light-antiheavy-antiheavy $q q \\bar Q\\bar Q$ case study

    OpenAIRE

    Bicudo, P; Cardoso, M.

    2015-01-01

    We address $q q \\bar Q\\bar Q$ exotic tetraquark bound states and resonances with a fully unitarized and microscopic quark model. We propose a triple string flip-flop potential, inspired in lattice QCD tetraquarks static potentials and fluxtubes, combining meson-meson and tetraquark potentials. Our potential goes up to the color excited potential, but neglects spin-tensor potentials. To search for bound states and resonances, we first solve the two-body mesonic problem. Then we develop fully u...

  4. RESONANCE

    Indian Academy of Sciences (India)

    Nuclear magnetic resonance (NMR) is a mani- festation of an intrinsic property of the nucleus, i.e. nuclear spin angular momen- tum. Spin angular momentum gives rise to magnetic moments. Thus, nuclei that pos- sess net magnetic moments behave like very small bar magnets. NMR spectroscopy in- volves the study of the ...

  5. Energy transfer of surface wind-induced currents to the deep ocean via resonance with the Coriolis force

    Science.gov (United States)

    Ashkenazy, Yosef

    2017-03-01

    There are two main comparable sources of energy to the deep ocean-winds and tides. However, the identity of the most efficient mechanism that transfers wind energy to the deep ocean is still debated. Here we study, using oceanic general circulation model simulations and analytic derivations, the way that the wind directly supplies energy down to the bottom of the ocean when it is stochastic and temporally correlated or when it is periodic with a frequency that matches the Coriolis frequency. Basically, under these, commonly observed, conditions, one of the wind components resonates with the Coriolis frequency. Using reanalysis surface wind data and our simple model, we show that about one-third of the kinetic energy that is associated with wind-induced currents resides in the abyssal ocean, highlighting the importance of the resonance of the wind with the Coriolis force.

  6. Anti-drift and auto-alignment mechanism for an astigmatic atomic force microscope system based on a digital versatile disk optical head.

    Science.gov (United States)

    Hwu, E-T; Illers, H; Wang, W-M; Hwang, I-S; Jusko, L; Danzebrink, H-U

    2012-01-01

    In this work, an anti-drift and auto-alignment mechanism is applied to an astigmatic detection system (ADS)-based atomic force microscope (AFM) for drift compensation and cantilever alignment. The optical path of the ADS adopts a commercial digital versatile disc (DVD) optical head using the astigmatic focus error signal. The ADS-based astigmatic AFM is lightweight, compact size, low priced, and easy to use. Furthermore, the optical head is capable of measuring sub-atomic displacements of high-frequency AFM probes with a sub-micron laser spot (~570 nm, FWHM) and a high-working bandwidth (80 MHz). Nevertheless, conventional DVD optical heads suffer from signal drift problems. In a previous setup, signal drifts of even thousands of nanometers had been measured. With the anti-drift and auto-alignment mechanism, the signal drift is compensated by actuating a voice coil motor of the DVD optical head. A nearly zero signal drift was achieved. Additional benefits of this mechanism are automatic cantilever alignment and simplified design.

  7. Stress relaxation and creep on living cells with the atomic force microscope: a means to calculate elastic moduli and viscosities of cell components

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Flores, Susana; Toca-Herrera, Jose Luis [Biosurfaces Unit, CIC BiomaGUNE, Paseo Miramon 182, E-20009 San Sebastian-Donostia (Spain); Benitez, Rafael [Departamento Matematicas, Centro Universitario de Plasencia, Universidad de Extremadura, Avenida Virgen del Puerto 2, E-10600 Plasencia (Spain); Vivanco, Maria dM, E-mail: jltocaherrera@cicbiomagune.es, E-mail: jose.toca-herrera@boku.ac.at [Cell Biology and Stem Cells Unit, CIC BioGUNE, Parque tecnologico de Bizkaia, Ed. 801A, E-48160 Derio (Spain)

    2010-11-05

    In this work we present a unified method to study the mechanical properties of cells using the atomic force microscope. Stress relaxation and creep compliance measurements permitted us to determine, the relaxation times, the Young moduli and the viscosity of breast cancer cells (MCF-7). The results show that the mechanical behaviour of MCF-7 cells responds to a two-layered model of similar elasticity but differing viscosity. Treatment of MCF-7 cells with an actin-depolymerising agent results in an overall decrease in both cell elasticity and viscosity, however to a different extent for each layer. The layer that undergoes the smaller decrease (36-38%) is assigned to the cell membrane/cortex while the layer that experiences the larger decrease (70-80%) is attributed to the cell cytoplasm. The combination of the method presented in this work, together with the approach based on stress relaxation microscopy (Moreno-Flores et al 2010 J. Biomech. 43 349-54), constitutes a unique AFM-based experimental framework to study cell mechanics. This methodology can also be extended to study the mechanical properties of biomaterials in general.

  8. Stress relaxation and creep on living cells with the atomic force microscope: a means to calculate elastic moduli and viscosities of cell components

    Science.gov (United States)

    Moreno-Flores, Susana; Benitez, Rafael; Vivanco, María dM; Toca-Herrera, José Luis

    2010-11-01

    In this work we present a unified method to study the mechanical properties of cells using the atomic force microscope. Stress relaxation and creep compliance measurements permitted us to determine, the relaxation times, the Young moduli and the viscosity of breast cancer cells (MCF-7). The results show that the mechanical behaviour of MCF-7 cells responds to a two-layered model of similar elasticity but differing viscosity. Treatment of MCF-7 cells with an actin-depolymerising agent results in an overall decrease in both cell elasticity and viscosity, however to a different extent for each layer. The layer that undergoes the smaller decrease (36-38%) is assigned to the cell membrane/cortex while the layer that experiences the larger decrease (70-80%) is attributed to the cell cytoplasm. The combination of the method presented in this work, together with the approach based on stress relaxation microscopy (Moreno-Flores et al 2010 J. Biomech. 43 349-54), constitutes a unique AFM-based experimental framework to study cell mechanics. This methodology can also be extended to study the mechanical properties of biomaterials in general.

  9. Topotactic changes on η-Mo{sub 4}O{sub 11} caused by biased atomic force microscope tip and cw-laser

    Energy Technology Data Exchange (ETDEWEB)

    Borovšak, Miloš, E-mail: milos.borovsak@ijs.si [Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia); Faculty for Mathematics and Physics, Jadranska ulica 19, 1000 Ljubljana (Slovenia); Šutar, Petra; Goreshnik, Evgeny [Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia); Mihailovic, Dragan [Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia); International Postgraduate School Jožef Stefan, Jamova cesta 39, 1000 Ljubljana (Slovenia)

    2015-11-01

    Highlights: • We report influencing electronic properties of η-Mo{sub 4}O{sub 11}. • With the biased AFM tip we induce the surface potential changes on η-Mo{sub 4}O{sub 11}. • We used cw-laser to induced similar effect on surface potential on η-Mo{sub 4}O{sub 11}. • We do not influence the surface and topography of the samples. • No change in topography of samples indicates the topotactic transformation. - Abstract: We present topotactic changes on Mo{sub 4}O{sub 11} crystals induced by a biased atomic force microscope tip and continuous laser. The transformation does not change the topography of the samples, while the surface potential shows remarkable changes on areas where the biased AFM tip was applied. No structural changes were observed by Raman spectroscopy, but AFM scans revealed changes to surface potential due to laser illumination. The observed phenomenon could be potentially useful for memristive memory devices considering the fact that properties of other molybdenum oxides vary from metallic to insulators.

  10. A Protocol for Using Förster Resonance Energy Transfer (FRET)-force Biosensors to Measure Mechanical Forces across the Nuclear LINC Complex.

    Science.gov (United States)

    Arsenovic, Paul T; Bathula, Kranthidhar; Conway, Daniel E

    2017-04-11

    The LINC complex has been hypothesized to be the critical structure that mediates the transfer of mechanical forces from the cytoskeleton to the nucleus. Nesprin-2G is a key component of the LINC complex that connects the actin cytoskeleton to membrane proteins (SUN domain proteins) in the perinuclear space. These membrane proteins connect to lamins inside the nucleus. Recently, a Förster Resonance Energy Transfer (FRET)-force probe was cloned into mini-Nesprin-2G (Nesprin-TS (tension sensor)) and used to measure tension across Nesprin-2G in live NIH3T3 fibroblasts. This paper describes the process of using Nesprin-TS to measure LINC complex forces in NIH3T3 fibroblasts. To extract FRET information from Nesprin-TS, an outline of how to spectrally unmix raw spectral images into acceptor and donor fluorescent channels is also presented. Using open-source software (ImageJ), images are pre-processed and transformed into ratiometric images. Finally, FRET data of Nesprin-TS is presented, along with strategies for how to compare data across different experimental groups.

  11. Multi-frequency force-detected electron spin resonance in the millimeter-wave region up to 150 GHz

    Energy Technology Data Exchange (ETDEWEB)

    Ohmichi, E., E-mail: ohmichi@harbor.kobe-u.ac.jp; Tokuda, Y.; Tabuse, R.; Tsubokura, D.; Okamoto, T. [Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501 (Japan); Ohta, H. [Molecular Photoscience Research Center, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501 (Japan)

    2016-07-15

    In this article, a novel technique is developed for multi-frequency force-detected electron spin resonance (ESR) in the millimeter-wave region. We constructed a compact ESR probehead, in which the cantilever bending is sensitively detected by a fiber-optic Fabry-Perot interferometer. With this setup, ESR absorption of diphenyl-picrylhydrazyl radical (<1 μg) was clearly observed at multiple frequencies of up to 150 GHz. We also observed the hyperfine splitting of low-concentration Mn{sup 2+} impurities(∼0.2%) in MgO.

  12. Separation of atomic-scale spin contrast on NiO(0 0 1) by magnetic resonance force microscopy

    Science.gov (United States)

    Arima, Eiji; Naitoh, Yoshitaka; Li, Yan Jun; Sugawara, Yasuhiro

    2017-10-01

    In magnetic exchange force microscopy, images contain the topographic contrast mixed with the spin contrast on the sample surface. In this study, we propose a new method of magnetic resonance force microscopy using ferromagnetic resonance to extract only the spin contrast. In this method, the magnetization of a magnetic cantilever is modulated by ferromagnetic resonance to separate the spin contrast and topographic contrast. We succeeded in obtaining a spin image of Ni atoms on a NiO (0 0 1) surface. Furthermore, we successfully detected the superexchange interaction between the tip apex atom and the second layer of Ni atoms.

  13. Lorentz force in water: evidence that hydronium cyclotron resonance enhances polymorphism.

    Science.gov (United States)

    D'Emilia, E; Giuliani, L; Lisi, A; Ledda, M; Grimaldi, S; Montagnier, L; Liboff, A R

    2015-01-01

    There is an ongoing question regarding the structure forming capabilities of water at ambient temperatures. To probe for different structures, we studied effects in pure water following magnetic field exposures corresponding to the ion cyclotron resonance of H3O(+). Included were measurements of conductivity and pH. We find that under ion cyclotron resonance (ICR) stimulation, water undergoes a transition to a form that is hydroxonium-like, with the subsequent emission of a transient 48.5 Hz magnetic signal, in the absence of any other measurable field. Our results indicate that hydronium resonance stimulation alters the structure of water, enhancing the concentration of EZ-water. These results are not only consistent with Del Giudice's model of electromagnetically coherent domains, but they can also be interpreted to show that these domains exist in quantized spin states.

  14. [Microscopic colitis].

    Science.gov (United States)

    Lukáš, Karel; Mandys, Václav

    2013-01-01

    Microscopic colitis is characterized by chronic or intermittent watery diarrhoea. Microscopic colitis is a common cause of chronic diarrhoea in predominantly older adults. The underlying mechanism in the pathogenesis of microscopic colitis remains unspecified. Microscopic colitis including colitis collagenous, lymphocytic, microscopic colitis with incomplete findings, minimal change colitis, eosinophilic colitis, Brainerd´s diarrhoea, graft-versus-host disease, mastocytic enterocolitis and postinfectious irritable bowel syndrome. Careful consideration of the clinical features and colonic mucosal biopsies usually lead to correct diagnosis. Treatments of microscopic colitis were based primarily on case reports and personal experience. Many medications have been proposed that either offer symptomatic relief (loperamide, cholestyramine) or had anti-inflammatory or immunosuppressive properties (aminosalicylates, steroids, adalimumab, azathioprine).

  15. Microwave Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Makes ultra-high-resolution field measurements. The Microwave Microscope (MWM) has been used in support of several NRL experimental programs involving sea...

  16. RESONANCE

    Indian Academy of Sciences (India)

    He compiled his ideas on quantum mechanics into a textbook. Principles of Quantum Mechanics, which remains a classic to this day. As Kragh writes,. Dirac's book was the only pre-1957 book on quantum mechanics that did not assume parity conservation in physical laws. It was only in 1957 that the weak force was shown.

  17. Novel radio-frequency and force-detected approaches in nuclear magnetic resonance

    NARCIS (Netherlands)

    Verhagen, Rieko

    2002-01-01

    Although Nuclear Magnetic Resonance (NMR) is a very powerful spectroscopic tool, a disadvantage of the technique is its relative insensitivity. With an increasing demand for the analysis of smaller structures in view of the rise of nanotechnology research, it is important to address the sensitivity

  18. Numerical Study of Forced Vibration Suppression by Parametric Anti-Resonance

    Czech Academy of Sciences Publication Activity Database

    Pešek, Luděk; Šulc, Petr; Půst, Ladislav

    2016-01-01

    Roč. 41, č. 3 (2016), s. 527-533 ISSN 0137-5075 R&D Projects: GA ČR GA16-04546S Institutional support: RVO:61388998 Keywords : active damping * parametric anti-resonance * external harmonic excitation Subject RIV: BI - Acoustics Impact factor: 0.816, year: 2016

  19. MEMS-based force-detected nuclear magnetic resonance spectrometer for in situ planetary exploration

    Science.gov (United States)

    George, T.; Leskowitz, G.; Madsen, L.; Weitekamp, D.; Tang, W.

    2000-01-01

    Nuclear Magnetic resonance (NMR) is a well-known spectroscopic technique used by chemists and is especially powerful in detecting the presence of water and distinguishing between arbitrary physisorbed and chemisorbed states. This ability is of particular importance in the search for extra-terrestrial life on planets such as Mars.

  20. Acoustofluidics: Theory and simulation of streaming and radiation forces at ultrasound resonances in microfluidic devices

    DEFF Research Database (Denmark)

    Bruus, Henrik

    2009-01-01

    fields, which are directly related to the acoustic radiation force on single particles and to the acoustic streaming of the liquid. For the radiation pressure effects, there is good agreement between theory and simulation, while the numeric results for the acoustic streaming effects are more problematic...

  1. Surface Plasmon Resonance (SPR for the Evaluation of Shear-Force-Dependent Bacterial Adhesion

    Directory of Open Access Journals (Sweden)

    Oleksandr Zagorodko

    2015-05-01

    Full Text Available The colonization of Escherichia coli (E. coli to host cell surfaces is known to be a glycan-specific process that can be modulated by shear stress. In this work we investigate whether flow rate changes in microchannels integrated on surface plasmon resonance (SPR surfaces would allow for investigating such processes in an easy and high-throughput manner. We demonstrate that adhesion of uropathogenic E. coli UTI89 on heptyl α-d-mannopyranoside-modified gold SPR substrates is minimal under almost static conditions (flow rates of 10 µL·min−1, and reaches a maximum at flow rates of 30 µL·min−1 (≈30 mPa. This concept is applicable to the investigation of any ligand-pathogen interactions, offering a robust, easy, and fast method for screening adhesion characteristics of pathogens to ligand-modified interfaces.

  2. A Lorentz force magnetometer based on a piezoelectric-on-silicon square-extensional mode micromechanical resonator

    Science.gov (United States)

    Ghosh, S.; Lee, J. E.-Y.

    2017-06-01

    In this letter, we present a Lorentz force magnetic field sensor based on a thin-film piezoelectric-on-silicon (TPoS) CMOS-compatible resonator for the detection of an out-of-plane (perpendicular to the plane of fabrication) magnetic field. We here exploit the fundamental breathing mode of vibration in a suspended square plate, which is commonly referred to as the square-extensional (SE) mode. The symmetric stress profile of the SE mode avails stresses in the two orthogonal in-plane axes to be effectively coupled into a charge output through the piezoelectric transducers. This in turn enhances the output motional current from the device, which effectively determines the responsivity of the device. In this context, the responsivity has been defined as a ratio of output motional current to the external magnetic field, which has been further normalized against the input reference current of the device. The reported device has recorded a responsivity of 6950 ppm/T (μA/A.T) at a resonant frequency of 5.28 MHz and a reasonable mechanical quality (Q) factor of 1056 in air.

  3. Martian Microscope

    Science.gov (United States)

    2004-01-01

    The microscopic imager (circular device in center) is in clear view above the surface at Meridiani Planum, Mars, in this approximate true-color image taken by the panoramic camera on the Mars Exploration Rover Opportunity. The image was taken on the 9th sol of the rover's journey. The microscopic imager is located on the rover's instrument deployment device, or arm. The arrow is pointing to the lens of the instrument. Note the dust cover, which flips out to the left of the lens, is open. This approximated color image was created using the camera's violet and infrared filters as blue and red.

  4. Characterization of Aerodynamic Forcing Functions for Embedded Rotor Resonant Response in a Multistage Compressor

    Science.gov (United States)

    Kormanik, Nicholas J., III

    There are two main objectives associated with this research: The first portion examines the flow field within the embedded stage of the Purdue 3-Stage Axial Compressor and the aerodynamics responsible for exciting a forced response condition on an embedded rotor. The second portion focuses on the upgrades made to the facility to accommodate a new compressor design, as well as the basic performance characteristics that were acquired for the baseline model. With the first phase of this research endeavor, the first chord-wise bending vibratory mode was examined with a standard stator 1 (S1) blade-count configuration (44 vanes). Next, a reduced S1 blade-count configuration (38 vanes) was implemented to observe how a reduced vane count might impact the forced response at the first torsion vibratory mode. To capture these aerodynamic considerations, stagnation pressure and thermal anemometry probes were used throughout the embedded stage to provide a detailed picture of the influence associated with rotor and stator wakes. These data were also used to observe the potential field effects from the downstream blade-rows. The overall purpose of this campaign was to provide accurate and reliable dataset that could be used to further enhance and validate the computational aeromechanics tools used by the GUIde V consortium, the sponsors for this research. The second phase of this involves the redesign of the Purdue 3-Stage Axial Compressor Facility to accommodate a new compressor, designed by Rolls-Royce, that requires higher mass flow rates, pressure ratios, speeds, and temperatures. Along with many of the mechanical upgrades associated with an adaptation of the driveline and throttle system, health-monitoring upgrades were made to improve the safety and integrity of the compressor system, particularly with respect to temperature and vibrations. Instrumentation improvements include new pressure transducers to observe higher pressures and mass flow rates and the implementation

  5. Surface conformations of anti-ricin aptamer and its affinity to ricin determined by atomic force microscopy and surface plasmon resonance

    Science.gov (United States)

    The specific interactions between ricin and anti-ricin aptamer were measured with atomic force microscopy (AFM) and surface plasmon resonance (SPR) spectrometry and the results were compared. In AFM, a single-molecule experiment with ricin functionalized AFM tip was used for scanning the aptamer mol...

  6. Ressonância magnética das vias lacrimais: estudo comparativo entre bobinas de superfície convencionais e microscópicas Magnetic resonance dacryocystography: comparison between conventional surface coils and microscopic coils

    Directory of Open Access Journals (Sweden)

    Luiz de Abreu Junior

    2008-08-01

    Full Text Available OBJETIVO: A ressonância magnética tem sido utilizada para avaliar as vias lacrimais, com vantagens em relação à dacriocistografia por raios-X. O objetivo deste trabalho é obter imagens de alta resolução utilizando bobinas de superfície microscópicas para avaliação de estruturas normais das vias lacrimais, comparando com o aspecto observado utilizando-se bobinas de superfície convencionais. MATERIAIS E MÉTODOS: Cinco voluntários assintomáticos, sem histórico de lacrimejamento, submeteram-se a ressonância magnética de alto campo, com bobinas de superfície (convencional e microscópica, com seqüência STIR após instilação de soro fisiológico. A identificação das estruturas anatômicas normais das vias lacrimais foi comparada utilizando-se as duas bobinas. Mediante uso de um sistema de escore, um valor médio de cada estrutura foi calculado por dois examinadores, consensualmente. RESULTADOS: Em 90% das vezes houve aumento do escore, atribuído à estrutura anatômica no estudo com a bobina microscópica. Em média, houve aumento de 1,17 ponto no escore, por estrutura anatômica visualizada, quando se utilizou a bobina microscópica. Observou-se, ainda, melhora subjetiva da relação sinal-ruído ao se utilizar a bobina microscópica. CONCLUSÃO: A dacriocistografia por ressonância magnética com bobinas microscópicas é um método adequado para o estudo das vias lacrimais, resultando em imagens de melhor qualidade quando comparada ao uso de bobinas de superfície convencionais.OBJECTIVE: Magnetic resonance imaging has been utilized in the evaluation of the lacrimal apparatus with some advantages over conventional dacryocystography. The present study was aimed at acquiring high-resolution images utilizing microscopic coils for evaluating typical structures of the lacrimal apparatus as compared with the findings observed with conventional surface coils. MATERIALS AND METHODS: Five asymptomatic volunteers with no history of

  7. Microscopic colitis

    DEFF Research Database (Denmark)

    Münch, A; Aust, D; Bohr, Jakob

    2012-01-01

    Microscopic colitis (MC) is an inflammatory bowel disease presenting with chronic, non-bloody watery diarrhoea and few or no endoscopic abnormalities. The histological examination reveals mainly two subtypes of MC, lymphocytic or collagenous colitis. Despite the fact that the incidence in MC has...

  8. Microscopic Polyangiitis

    Science.gov (United States)

    ... share a variety of features but possess sufficient differences as to justify separate classifications. Who gets Microscopic Polyangiitis? A typical patient MPA can affect individuals from all ethnic backgrounds and any age group. In the United States, the typical MPA patient ...

  9. Microscopic colitis.

    Science.gov (United States)

    Ianiro, Gianluca; Cammarota, Giovanni; Valerio, Luca; Annicchiarico, Brigida Eleonora; Milani, Alessandro; Siciliano, Massimo; Gasbarrini, Antonio

    2012-11-21

    Microscopic colitis may be defined as a clinical syndrome, of unknown etiology, consisting of chronic watery diarrhea, with no alterations in the large bowel at the endoscopic and radiologic evaluation. Therefore, a definitive diagnosis is only possible by histological analysis. The epidemiological impact of this disease has become increasingly clear in the last years, with most data coming from Western countries. Microscopic colitis includes two histological subtypes [collagenous colitis (CC) and lymphocytic colitis (LC)] with no differences in clinical presentation and management. Collagenous colitis is characterized by a thickening of the subepithelial collagen layer that is absent in LC. The main feature of LC is an increase of the density of intra-epithelial lymphocytes in the surface epithelium. A number of pathogenetic theories have been proposed over the years, involving the role of luminal agents, autoimmunity, eosinophils, genetics (human leukocyte antigen), biliary acids, infections, alterations of pericryptal fibroblasts, and drug intake; drugs like ticlopidine, carbamazepine or ranitidine are especially associated with the development of LC, while CC is more frequently linked to cimetidine, non-steroidal antiinflammatory drugs and lansoprazole. Microscopic colitis typically presents as chronic or intermittent watery diarrhea, that may be accompanied by symptoms such as abdominal pain, weight loss and incontinence. Recent evidence has added new pharmacological options for the treatment of microscopic colitis: the role of steroidal therapy, especially oral budesonide, has gained relevance, as well as immunosuppressive agents such as azathioprine and 6-mercaptopurine. The use of anti-tumor necrosis factor-α agents, infliximab and adalimumab, constitutes a new, interesting tool for the treatment of microscopic colitis, but larger, adequately designed studies are needed to confirm existing data.

  10. A Student-Built Scanning Tunneling Microscope

    Science.gov (United States)

    Ekkens, Tom

    2015-01-01

    Many introductory and nanotechnology textbooks discuss the operation of various microscopes including atomic force (AFM), scanning tunneling (STM), and scanning electron microscopes (SEM). In a nanotechnology laboratory class, students frequently utilize microscopes to obtain data without a thought about the detailed operation of the tool itself.…

  11. Contrast artifacts in tapping tip atomic force microscopy

    DEFF Research Database (Denmark)

    Kyhle, Anders; Sørensen, Alexis Hammer; Zandbergen, Julie Bjerring

    1998-01-01

    When recording images with an atomic force microscope using the resonant vibrating cantilever mode, surprising strange results are often achieved. Typical artifacts are strange contours, unexpected height shifts, and sudden changes of the apparent resolution in the acquired images. Such artifacts...

  12. MDM2–MDM4 molecular interaction investigated by atomic force spectroscopy and surface plasmon resonance

    Science.gov (United States)

    Moscetti, Ilaria; Teveroni, Emanuela; Moretti, Fabiola; Bizzarri, Anna Rita; Cannistraro, Salvatore

    2016-01-01

    Murine double minute 2 (MDM2) and 4 (MDM4) are known as the main negative regulators of p53, a tumor suppressor. They are able to form heterodimers that are much more effective in the downregulation of p53. Therefore, the MDM2–MDM4 complex could be a target for promising therapeutic restoration of p53 function. To this aim, a deeper understanding of the molecular mechanisms underlining the heterodimerization is needed. The kinetic and thermodynamic characterization of the MDM2–MDM4 complex was performed with two complementary approaches: atomic force spectroscopy and surface plasmon resonance. Both techniques revealed an equilibrium dissociation constant (KD) in the micromolar range for the MDM2–MDM4 heterodimer, similar to related complexes involved in the p53 network. Furthermore, the MDM2–MDM4 complex is characterized by a relatively high free energy, through a single energy barrier, and by a lifetime in the order of tens of seconds. New insights into the MDM2–MDM4 interaction could be highly important for developing innovative anticancer drugs focused on p53 reactivation. PMID:27621617

  13. Characterization of surface modification in atomic force microscope-induced nanolithography of oxygen deficient La0.67Ba0.33MnO3−δ thin films

    Directory of Open Access Journals (Sweden)

    E. Kevin Tanyi

    2014-12-01

    Full Text Available We report our studies of the nanolithographic surface modifications induced by an Atomic Force Microscope (AFM in epitaxial thin films of oxygen deficient Lanthanum Barium Manganese Oxide (La0.67Ba0.33MnO3−δ. The pattern characteristics depend on the tip voltage, tip polarity, voltage duration, tip force, and humidity. We have used Electron Energy Dispersive X-Ray Spectroscopy (EDS to analyze the chemical changes associated with the surface modifications produced with a negatively biased AFM tip. A significant increase in the oxygen stoichiometry for the patterned regions relative to the pristine film surface is observed. The results also indicate changes in the cation stoichiometry, specifically a decrease in the Lanthanum and Manganese concentrations and an increase in the Barium concentration in the patterned regions.

  14. Quantification of synovistis by MRI: correlation between dynamic and static gadolinium-enhanced magnetic resonance imaging and microscopic and macroscopic signs of synovial inflammation

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Stoltenberg, M; Løvgreen-Nielsen, P

    1998-01-01

    injection, as the highest correlation coefficients to histologic inflammation were observed in this interval. Dynamic MRI can be used to determine synovial inflammation. Evaluation of large synovial areas one-half to one minute after Gd injection best reflects joint inflammation....... as at the four biopsy sites, and compared to synovial pathology. The rate of early enhancement of the total synovial membrane of the preselected slice, determined by dynamic MRI, was highly correlated with microscopic evidence of active inflammation (Spearman p = 0.73; p ... knees with and without synovial inflammation with a high predictive value (0.81-0.90). Moderate and severe inflammation could not be differentiated. The early enhancement rate was correlated with histologic features of active inflammation, particularly vessel proliferation and mononuclear leucocyte...

  15. Quantification of synovistis by MRI: correlation between dynamic and static gadolinium-enhanced magnetic resonance imaging and microscopic and macroscopic signs of synovial inflammation

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Stoltenberg, M; Løvgreen-Nielsen, P

    1998-01-01

    characteristics were graded at four preselected biopsy sites. Preoperative T1-weighted dynamic fast low angle shot and static spin-echo Gd-enhanced MRI were performed. The dynamic enhancement rate and the static enhancement were measured in the entire synovial membrane of a preselected slice as well...... as at the four biopsy sites, and compared to synovial pathology. The rate of early enhancement of the total synovial membrane of the preselected slice, determined by dynamic MRI, was highly correlated with microscopic evidence of active inflammation (Spearman p = 0.73; p ... infiltration. Dynamic evaluation of small synovial sections at the biopsy sites and static spin-echo MRI resulted in considerably weaker correlations to histologic inflammation than dynamic evaluation of the total synovium. The optimal time for enhancement measurements was one-half to one minute after Gd...

  16. Electron magnetic resonance data on high-spin Mn(III; S=2) ions in porphyrinic and salen complexes modeled by microscopic spin Hamiltonian approach.

    Science.gov (United States)

    Tadyszak, Krzysztof; Rudowicz, Czesław; Ohta, Hitoshi; Sakurai, Takahiro

    2017-10-01

    The spin Hamiltonian (SH) parameters experimentally determined by EMR (EPR) may be corroborated or otherwise using various theoretical modeling approaches. To this end semiempirical modeling is carried out for high-spin (S=2) manganese (III) 3d 4 ions in complex of tetraphenylporphyrinato manganese (III) chloride (MnTPPCl). This modeling utilizes the microscopic spin Hamiltonians (MSH) approach developed for the 3d 4 and 3d 6 ions with spin S=2 at orthorhombic and tetragonal symmetry sites in crystals, which exhibit an orbital singlet ground state. Calculations of the zero-field splitting (ZFS) parameters and the Zeeman electronic (Ze) factors (g || =g z , g ⊥ =g x =g y ) are carried out for wide ranges of values of the microscopic parameters using the MSH/VBA package. This enables to examine the dependence of the theoretically determined ZFS parameters b k q (in the Stevens notation) and the Zeeman factors g i on the spin-orbit (λ), spin-spin (ρ) coupling constant, and the ligand-field energy levels (Δ i ) within the 5 D multiplet. The results are presented in suitable tables and graphs. The values of λ, ρ, and Δ i best describing Mn(III) ions in MnTPPCl are determined by matching the theoretical second-rank ZFSP b 2 0 (D) parameter and the experimental one. The fourth-rank ZFS parameters (b 4 0 , b 4 4 ) and the ρ (spin-spin)-related contributions, which have been omitted in previous studies, are considered for the first time here and are found important. Semiempirical modeling results are compared with those obtained recently by the density functional theory (DFT) and/or ab initio methods. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Study of the mapping mechanism of ferroelectric domains with the scanning force microscope; Untersuchung der Abbildungsmechanismen ferroelektrischer Domaenen mit dem Rasterkraftmikroskop

    Energy Technology Data Exchange (ETDEWEB)

    Jungk, T.

    2006-12-15

    The piezo-force microscopy (PFM) allows the mapping of ferroelectric domains until the nanometer range. In spite of its simple function principle it was hitherto not completely understood. In ordser to develop the PFM further to a quantitative analysis method its methodical aspects were analyzed. It was shown that the fundamental mapping mechanism is based on the inverse piezo-effect. Different artefacts to be found in the literature could therefore be reduced to a measurement background. Furthermore the influence of the electrode geometry was analyzed. The width of doamin walls was systematically measured and simulated with a mode, whereby a maximal resolution of 17 nm was reached. By the development of a correction procedure for the exact detection of the forces acting on the spring-beam the lateral signals measured on domain walls could by newly interpreted. So the ''Lateral Electrostatic Force Microscopy'' was developed.

  18. Magnetic-force-microscope Study of Interlayer _Kinks_ in Individual Vortices in Underdoped Cuprate YBa2Cu3O6 x Superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Luan, Lan

    2010-04-05

    We use magnetic force microscopy to both image and manipulate individual vortex lines threading single crystalline YBa{sub 2}Cu{sub 3}O{sub 6.4}, a layered superconductor. We find that when we pull the top of a pinned vortex, it may not tilt smoothly. Sometimes, we observe a vortex to break into discrete segments that can be described as short stacks of pancake vortices, similar to the 'kinked' structure proposed by Benkraouda and Clem. Quantitative analysis gives an estimate of the pinning force and the coupling between the stacks. Our measurements highlight the discrete nature of stacks of pancake vortices in layered superconductors.

  19. Exploring the retention properties of CaF2 nanoparticles as possible additives for dental care application with tapping-mode atomic force microscope in liquid

    Directory of Open Access Journals (Sweden)

    Matthias Wasem

    2014-01-01

    Full Text Available Amplitude-modulation atomic force microscopy (AM-AFM is used to determine the retention properties of CaF2 nanoparticles adsorbed on mica and on tooth enamel in liquid. From the phase-lag of the forced cantilever oscillation the local energy dissipation at the detachment point of the nanoparticle was determined. This enabled us to compare different as-synthesized CaF2 nanoparticles that vary in shape, size and surface structure. CaF2 nanoparticles are candidates for additives in dental care products as they could serve as fluorine-releasing containers preventing caries during a cariogenic acid attack on the teeth. We show that the adherence of the nanoparticles is increased on the enamel substrate compared to mica, independently of the substrate roughness, morphology and size of the particles.

  20. On microscopic theory of radiative nuclear reaction characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Kamerdzhiev, S. P. [National Research Centre “Kurchatov Institute” (Russian Federation); Achakovskiy, O. I., E-mail: oachakovskiy@ippe.ru; Avdeenkov, A. V. [Institute for Physics and Power Engineering (Russian Federation); Goriely, S. [Institut d’Astronomie et d’Astrophysique (Belgium)

    2016-07-15

    A survey of some results in the modern microscopic theory of properties of nuclear reactions with gamma rays is given. First of all, we discuss the impact of Phonon Coupling (PC) on the Photon Strength Function (PSF) because it represents the most natural physical source of additional strength found for Sn isotopes in recent experiments that could not be explained within the standard HFB + QRPA approach. The self-consistent version of the Extended Theory of Finite Fermi Systems in the Quasiparticle Time Blocking Approximation is applied. It uses the HFB mean field and includes both the QRPA and PC effects on the basis of the SLy4 Skyrme force. With our microscopic E1 PSFs, the following properties have been calculated for many stable and unstable even–even semi-magic Sn and Ni isotopes as well as for double-magic {sup 132}Sn and {sup 208}Pb using the reaction codes EMPIRE and TALYS with several Nuclear Level Density (NLD) models: (1) the neutron capture cross sections; (2) the corresponding neutron capture gamma spectra; (3) the average radiative widths of neutron resonances. In all the properties considered, the PC contribution turned out to be significant, as compared with the standard QRPA one, and necessary to explain the available experimental data. The results with the phenomenological so-called generalized superfluid NLD model turned out to be worse, on the whole, than those obtained with the microscopic HFB + combinatorial NLD model. The very topical question about the M1 resonance contribution to PSFs is also discussed.Finally, we also discuss the modern microscopic NLD models based on the self-consistent HFB method and show their relevance to explain the experimental data as compared with the phenomenological models. The use of these self-consistent microscopic approaches is of particular relevance for nuclear astrophysics, but also for the study of double-magic nuclei.

  1. Electron spin resonance probe for the solvation of ionomer membranes and other microscopically heterogeneous systems. Cu[sup 2+] in nafion, sephadex and silica gel

    Energy Technology Data Exchange (ETDEWEB)

    Bednarek, J.; Schlick, S. (Univ. of Detroit, MI (United States))

    1992-01-01

    Cu[sup 2+] is a sensitive electron spin resonance (ESR) probe for the penetration of various polar solvents in membranes made of Nafion and as an indicator for the replacement of one solvent by another. The ESR parameters (g and [sup 63]Cu hyperfine tensors) can be translated into a structure of the solvent around the cation. The replacement of a solvent in the membrane by another depends on the polarity of the two solvents. The solvent with the largest dielectric constant, N-methylformamide (NMF), can be replaced by water but not by methanol or acetonitrile (dielectric constants 182, 78.5, 32.7, and 37.5, respectively). Preferential solvation of the cation by water in three water/acetonitrile mixtures (9:1, 1:1, and 1:9 by volume) in contact with silica gel, Sephadex, and Nafion has been observed in various degrees. Nafion is most selective, followed by Sephadex and by silica gel. The selectivity appears to be related to electrostatic interactions which are strongest in Nafion and weakest in silica gel. 43 refs., 6 figs., 1 tab.

  2. Probing the microscopic structural organization of neat ionic liquids (ILs) and ionic liquid-based gels through resonance energy transfer (RET) studies.

    Science.gov (United States)

    Majhi, Debashis; Sarkar, Moloy

    2017-08-30

    With the aim to understand the role of the ionic constituents of ionic liquids (ILs) in their structural organization, resonance energy transfer (RET) studies between ionic liquids (donor) and rhodamine 6G (acceptor) have been investigated. RET studies have been exploited for the present investigation due to the fact that the said process is extremely sensitive to the distance, and a change in the donor-acceptor distance due to a change in the structural organization can be probed. Basically, steady state and time-resolved fluorescence measurements have been carried out in two different sets of ILs, where in one set (1-ethyl-3-methyl imidazolium alkyl sulfate) the alkyl side chain length on the anionic moiety is systematically varied and in the other set variation is done on the cation (aromatic and nonaromatic). The data related to the RET events have been analyzed in light of Förster theory. A clear rise time in the fluorescence intensity decay profile of the acceptor has unequivocally established the RET process between the donor and acceptor. Interestingly, the rise times and energy transfer efficiencies are also observed to vary with a variation in the alkyl chain length as well as the nature of the cations. More interestingly, the donor-acceptor distance (R DA ) is observed to increase from 35.0 Å to 47.5 Å upon increasing the anion chain length from ethyl to octyl. However, R DA is found to decrease (40.5 Å to 34.9 Å) upon going from 1-methyl-3-butylimidazolium to 1-butyl-1-methylpyrrolidinium cations. The variation of the relevant RET parameters for the two sets of ILs has been rationalized by considering the change in the structural organization of the respective set of ILs. Additionally, observation of the RET process also in an IL-based gel system indicates the potential use of this fluorescent gel material for future applications.

  3. Nuclear magnetic resonance: Its role as a microscopic probe of the electronic and magnetic properties of High-Tc superconductors and related materials

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Byoung Jin [Iowa State Univ., Ames, IA (United States)

    1995-12-27

    NMR experiments are reported for Sr2CuO2Cl2, HgBa2CuO4+d, YNi2B2C and YBa2Cu3O7. NMR studies typify three different aspects of microscopic properties of HTSC. In non-superconducting antiferromagnetic (AF) prototype Sr2CuO2Cl2, we used NMR to investigate Cu2+ correlated spin dynamics and AF phase transition in CuO2 layers. In the superconductors, we used NMR both to investigate the electronic properties of the Fermi-liquid in normal and superconducting states and to investigate flux lattice and flux-line dynamics in the superconducting state in presence of magnetic field. A summary of each study is given: 35Cl NMR was measured in Sr2CuO2Cl2 single crystals with TN=257K. 35Cl NMR relaxation rates showed crossover of Cu2+ spin dynamics from Heisenberg to XY-like correlation at 290 K well above TN. A field-dependent TN for H$\\perp$c was observed and explained by a field-induced Ising-like anisotropy in ab plane. 199Hg NMR was measured in HgBa2CuO4+d. Properties of the Fermi-liquid are characterized by a single-spin fluid picture and opening of a spin pseudo-gap at q=0 above Tc. Below Tc spin component of Knight shift decreases rapidly in agreement with prediction for d-wave pairing scheme. 11B and 89Y NMR/magnetization were measured in YNi2B2C. Temperature dependence of 11B Knight shift and of the NSLR gave a normal state which agrees with the Korringa relation, indicating that the AF fluctuations on the Ni sublattice are negligible. Opening of the superconducting gap obeys BCS. A NMR approach to investigate vortex thermal motion in HTSC is presented, based on contribution of thermal flux-lines motion

  4. Quantitative Subsurface Atomic Structure Fingerprint for 2D Materials and Heterostructures by First-Principles-Calibrated Contact-Resonance Atomic Force Microscopy.

    Science.gov (United States)

    Tu, Qing; Lange, Björn; Parlak, Zehra; Lopes, Joao Marcelo J; Blum, Volker; Zauscher, Stefan

    2016-07-26

    Interfaces and subsurface layers are critical for the performance of devices made of 2D materials and heterostructures. Facile, nondestructive, and quantitative ways to characterize the structure of atomically thin, layered materials are thus essential to ensure control of the resultant properties. Here, we show that contact-resonance atomic force microscopy-which is exquisitely sensitive to stiffness changes that arise from even a single atomic layer of a van der Waals-adhered material-is a powerful experimental tool to address this challenge. A combined density functional theory and continuum modeling approach is introduced that yields sub-surface-sensitive, nanomechanical fingerprints associated with specific, well-defined structure models of individual surface domains. Where such models are known, this information can be correlated with experimentally obtained contact-resonance frequency maps to reveal the (sub)surface structure of different domains on the sample.

  5. Combination resonances in forced vibration of spar-type floating substructure with nonlinear coupled system in heave and pitch motion

    Directory of Open Access Journals (Sweden)

    Eung-Young Choi

    2016-05-01

    Full Text Available A spar-type floating substructure that is being widely used for offshore wind power generation is vulnerable to resonance in the heave direction because of its small water plane area. For this reason, the stable dynamic response of this floating structure should be ensured by accurately identifying the resonance characteristics. The purpose of this study is to analyze the characteristics of the combination resonance between the excitation frequency of a regular wave and natural frequencies of the floating substructure. First, the nonlinear equations of motion with two degrees of freedom are derived by assuming that the floating substructure is a rigid body, where the heaving motion and pitching motions are coupled. Moreover, to identify the characteristics of the combination resonance, the nonlinear term in the nonlinear equations is approximated up to the second order using the Taylor series expansion. Furthermore, the validity of the approximate model is confirmed through a comparison with the results of a numerical analysis which is made by applying the commercial software ANSYS AQWA to the full model. The result indicates that the combination resonance occurs at the frequencies of ω±ωn5 and 2ωn5 between the excitation frequency (ω of a regular wave and the natural frequency of the pitching motion (ωn5 of the floating substructure.

  6. Reduced hydrophobic interaction of polystyrene surfaces by spontaneous segregation of block copolymers with oligo (ethylene glycol) methyl ether methacrylate blocks: force measurements in water using atomic force microscope with hydrophobic probes.

    Science.gov (United States)

    Zhang, Rui; Seki, Akiko; Ishizone, Takashi; Yokoyama, Hideaki

    2008-05-20

    Reduction of hydrophobic interaction in water is important in biological interfaces. In our previous work, we have found that poly(styrene- b-triethylene glycol methyl ether methacrylate) (PS-PME3MA) segregates the PME3MA block to the surface in hydrophobic environment, such as in air or in a vacuum, and shows remarkable resistance against adsorption or adhesion of proteins, platelets, and cells in water. In this paper, we report that atomic force microscopy (AFM) with hydrophobic probes can directly monitor the reduced hydrophobic interaction of the PS surfaces modified by poly(styrene- b-origoethylene glycol methyl ether methacrylate) (PS-PME NMA), where N is the number of ethylene glycol units. The pull-off forces between the hydrophobic probes that are coated with octyltrichlorosilane (OLTS) and the PS-PME NMA modified polystyrene (PS) surfaces in water were measured. The absolute spring constants and tip-curvatures of the AFM cantilevers were measured to compute the work of adhesion by the Johnson, Kendall, and Roberts (JKR) theory, which relates the pull-off force at which the separation occurs between a hemisphere and a plane to the work of adhesion. The hydrophobic interactions between the hydrophobic tip and polymer surfaces in water were greatly reduced with the segregated PME NMA blocks. The hydrophobic interactions decrease with increasing N of the series of PS-PME NMA and show a correlation with the amount of protein adsorbed.

  7. Observation of Switchable Photoresponse of a Monolayer WSe 2 –MoS 2 Lateral Heterostructure via Photocurrent Spectral Atomic Force Microscopic Imaging

    KAUST Repository

    Son, Youngwoo

    2016-04-27

    In the pursuit of two-dimensional (2D) materials beyond graphene, enormous advances have been made in exploring the exciting and useful properties of transition metal dichalcogenides (TMDCs), such as a permanent band gap in the visible range and the transition from indirect to direct band gap due to 2D quantum confinement, and their potential for a wide range of device applications. In particular, recent success in the synthesis of seamless monolayer lateral heterostructures of different TMDCs via chemical vapor deposition methods has provided an effective solution to producing an in-plane p-n junction, which is a critical component in electronic and optoelectronic device applications. However, spatial variation of the electronic and optoelectonic properties of the synthesized heterojunction crystals throughout the homogeneous as well as the lateral junction region and the charge carrier transport behavior at their nanoscale junctions with metals remain unaddressed. In this work, we use photocurrent spectral atomic force microscopy to image the current and photocurrent generated between a biased PtIr tip and a monolayer WSe2-MoS2 lateral heterostructure. Current measurements in the dark in both forward and reverse bias reveal an opposite characteristic diode behavior for WSe2 and MoS2, owing to the formation of a Schottky barrier of dissimilar properties. Notably, by changing the polarity and magnitude of the tip voltage applied, pixels that show the photoresponse of the heterostructure are observed to be selectively switched on and off, allowing for the realization of a hyper-resolution array of the switchable photodiode pixels. This experimental approach has significant implications toward the development of novel optoelectronic technologies for regioselective photodetection and imaging at nanoscale resolutions. Comparative 2D Fourier analysis of physical height and current images shows high spatial frequency variations in substrate/MoS2 (or WSe2) contact that

  8. Measurement of Laterally Induced Optical Forces at the Nanoscale

    CERN Document Server

    Huang, Fei; Wickramasinghe, Hemanta Kumar

    2016-01-01

    We demonstrate the measurement of laterally induced optical forces using an Atomic Force Microscope (AFM). The lateral electric field distribution between a gold coated AFM probe and a nano-aperture in a gold film is mapped by measuring the lateral optical force between the apex of the AFM probe and the nano-aperture. Torsional eigenmodes of an AFM cantilever probe were used to detect the laterally induced optical forces. We engineered the cantilever shape using a focused ion beam to enhance the torsional eigenmode resonance. The measured lateral optical force agrees well with simulations. This technique can be extended to simultaneously detect both lateral and longitudinal optical forces at the nanoscale by using an AFM cantilever as a multichannel detector. This will enable simultaneous Photon Induced Force Microscopy (PIFM) detection of molecular responses with different incident field polarizations. The technique can be implemented on both cantilever and tuning fork based AFMs.

  9. Photothermally excited force modulation microscopy for broadband nanomechanical property measurements

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Ryan, E-mail: ryan.wagner@nist.gov; Killgore, Jason P. [Material Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305 (United States)

    2015-11-16

    We demonstrate photothermally excited force modulation microscopy (PTE FMM) for mechanical property characterization across a broad frequency range with an atomic force microscope (AFM). Photothermal excitation allows for an AFM cantilever driving force that varies smoothly as a function of drive frequency, thus avoiding the problem of spurious resonant vibrations that hinder piezoelectric excitation schemes. A complication of PTE FMM is that the sub-resonance cantilever vibration shape is fundamentally different compared to piezoelectric excitation. By directly measuring the vibrational shape of the cantilever, we show that PTE FMM is an accurate nanomechanical characterization method. PTE FMM is a pathway towards the characterization of frequency sensitive specimens such as polymers and biomaterials with frequency range limited only by the resonance frequency of the cantilever and the low frequency limit of the AFM.

  10. Dispersion Forces

    CERN Document Server

    Buhmann, Stefan Yoshi

    2012-01-01

    In this book, a modern unified theory of dispersion forces on atoms and bodies is presented which covers a broad range of advanced aspects and scenarios. Macroscopic quantum electrodynamics is shown to provide a powerful framework for dispersion forces which allows for discussing general properties like their non-additivity and the relation between microscopic and macroscopic interactions. It is demonstrated how the general results can be used to obtain dispersion forces on atoms in the presence of bodies of various shapes and materials. Starting with a brief recapitulation of volume I, this volume II deals especially with bodies of irregular shapes, universal scaling laws, dynamical forces on excited atoms, enhanced forces in cavity quantum electrodynamics, non-equilibrium forces in thermal environments and quantum friction. The book gives both the specialist and those new to the field a thorough overview over recent results in the field. It provides a toolbox for studying dispersion forces in various contex...

  11. Atomic-resolution imaging in liquid by frequency modulation atomic force microscopy using small cantilevers with megahertz-order resonance frequencies.

    Science.gov (United States)

    Fukuma, T; Onishi, K; Kobayashi, N; Matsuki, A; Asakawa, H

    2012-04-06

    In this study, we have investigated the performance of liquid-environment FM-AFM with various cantilevers having different dimensions from theoretical and experimental aspects. The results show that reduction of the cantilever dimensions provides improvement in the minimum detectable force as long as the tip height is sufficiently long compared with the width of the cantilever. However, we also found two important issues to be overcome to achieve this theoretically expected performance. The stable photothermal excitation of a small cantilever requires much higher pointing stability of the exciting laser beam than that for a long cantilever. We present a way to satisfy this stringent requirement using a temperature controlled laser diode module and a polarization-maintaining optical fiber. Another issue is associated with the tip. While a small carbon tip formed by electron beam deposition (EBD) is desirable for small cantilevers, we found that an EBD tip is not suitable for atomic-scale applications due to the weak tip-sample interaction. Here we show that the tip-sample interaction can be greatly enhanced by coating the tip with Si. With these improvements, we demonstrate atomic-resolution imaging of mica in liquid using a small cantilever with a megahertz-order resonance frequency. In addition, we experimentally demonstrate the improvement in the minimum detectable force obtained by the small cantilever in measurements of oscillatory hydration forces.

  12. A comparative evaluation of the effect of 5.25% sodium hypochlorite and 2% chlorhexidine on the surface texture of Gutta-percha and resilon cones using atomic force microscope.

    Science.gov (United States)

    Tilakchand, Mahima; Naik, Balaram; Shetty, Abhijith S

    2014-01-01

    The purpose of this study was to investigate the effects of 5.25% sodium hypochlorite (NaOCl) and 2% chlorhexidine (CHX) on Gutta-percha and Resilon cones using an atomic force microscope (AFM). Gutta-percha cones (n = 15) and Resilon cones (n = 15) were cut 3 mm from their tip, attached to a glass slide with cyanoacrylate glue and immersed in 5.25% NaOCl and CHX for 1, 5, 10, 20 and 30 min. Five each of Gutta-percha and Resilon cones not treated with any disinfectant were used as control. The analysis of the surface topography was performed on the region between 1 and 2 mm from the tip using the AFM. The root mean square (RMS) parameters for contact mode imaging were measured. The differences between RMS values were tested by SPSS-16.0 version statistical software [IBM SPSS (Statistical Product and Service Solutions) Data Software, Chicago, US] using Kruskal-Wallis ANOVA, Mann-Whitney U-test and Wilcoxon matched pairs test. There was no deterioration in the surfac e topography of Gutta-percha and Resilon when treated with 2% CHX in comparison to baseline (P < 0.05). Resilon exhibited no deterioration in topography when immersed in 5.25% NaOCl. There was a significant decrease in the mean RMS values of Gutta-percha treated with NaOCl from the control at time intervals of 1, 5, 10, 20 and 30 min.

  13. An apertureless near-field microscope for fluorescence imaging

    OpenAIRE

    Yang, T. J.; Lessard, Guillaume A.; Quake, Stephen R.

    2000-01-01

    We describe an apertureless near field microscope for imaging fluorescent samples. Optical contrast is generated by exploiting fluorescent quenching near a metallized atomic force microscope tip. This microscope has been used to image fluorescent latex beads with subdiffraction limit resolution. The use of fluorescence allows us to prove that the contrast mechanism is indeed spectroscopic in origin.

  14. A video rate laser scanning confocal microscope

    Science.gov (United States)

    Ma, Hongzhou; Jiang, James; Ren, Hongwu; Cable, Alex E.

    2008-02-01

    A video-rate laser scanning microscope was developed as an imaging engine to integrate with other photonic building blocks to fulfill various microscopic imaging applications. The system is quipped with diode laser source, resonant scanner, galvo scanner, control electronic and computer loaded with data acquisition boards and imaging software. Based on an open frame design, the system can be combined with varies optics to perform the functions of fluorescence confocal microscopy, multi-photon microscopy and backscattering confocal microscopy. Mounted to the camera port, it allows a traditional microscope to obtain confocal images at video rate. In this paper, we will describe the design principle and demonstrate examples of applications.

  15. Nonlinear resonances

    CERN Document Server

    Rajasekar, Shanmuganathan

    2016-01-01

    This introductory text presents the basic aspects and most important features of various types of resonances and anti-resonances in dynamical systems. In particular, for each resonance, it covers the theoretical concepts, illustrates them with case studies, and reviews the available information on mechanisms, characterization, numerical simulations, experimental realizations, possible quantum analogues, applications and significant advances made over the years. Resonances are one of the most fundamental phenomena exhibited by nonlinear systems and refer to specific realizations of maximum response of a system due to the ability of that system to store and transfer energy received from an external forcing source. Resonances are of particular importance in physical, engineering and biological systems - they can prove to be advantageous in many applications, while leading to instability and even disasters in others. The book is self-contained, providing the details of mathematical derivations and techniques invo...

  16. Food toxin detection with atomic force microscope

    Science.gov (United States)

    Externally introduced toxins or internal spoilage correlated pathogens and their metabolites are all potential sources of food toxins. To prevent and protect unsafe food, many food toxin detection techniques have been developed to detect various toxins for quality control. Although several routine m...

  17. Transmission positron microscopes

    Energy Technology Data Exchange (ETDEWEB)

    Doyama, Masao [Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193 (Japan)]. E-mail: doyama@ntu.ac.jp; Kogure, Yoshiaki [Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193 (Japan); Inoue, Miyoshi [Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193 (Japan); Kurihara, Toshikazu [Institute of Materials Structure Science (IMSS), High Energy Accelerator, Research Organization (KEK), Ohno 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Yoshiie, Toshimasa [Reactor Research Institute, Kyoto University, Noda, Kumatori, Osaka 590-0451 (Japan); Oshima, Ryuichiro [Research Institute for Advanced Science and Technology, Osaka Prefecture University (Japan); Matsuya, Miyuki [Electron Optics Laboratory (JEOL) Ltd., Musashino 3-1-2, Akishima 196-0021 (Japan)

    2006-02-28

    Immediate and near-future plans for transmission positron microscopes being built at KEK, Tsukuba, Japan, are described. The characteristic feature of this project is remolding a commercial electron microscope to a positron microscope. A point source of electrons kept at a negative high voltage is changed to a point source of positrons kept at a high positive voltage. Positional resolution of transmission microscopes should be theoretically the same as electron microscopes. Positron microscopes utilizing trapping of positrons have always positional ambiguity due to the diffusion of positrons.

  18. Fourier Transform Infrared (FTIR) Spectroscopy, Ultraviolet Resonance Raman (UVRR) Spectroscopy, and Atomic Force Microscopy (AFM) for Study of the Kinetics of Formation and Structural Characterization of Tau Fibrils.

    Science.gov (United States)

    Ramachandran, Gayathri

    2017-01-01

    Kinetic studies of tau fibril formation in vitro most commonly employ spectroscopic probes such as thioflavinT fluorescence and laser light scattering or negative stain transmission electron microscopy. Here, I describe the use of Fourier transform infrared (FTIR) spectroscopy, ultraviolet resonance Raman (UVRR) spectroscopy, and atomic force microscopy (AFM) as complementary probes for studies of tau aggregation. The sensitivity of vibrational spectroscopic techniques (FTIR and UVRR) to secondary structure content allows for measurement of conformational changes that occur when the intrinsically disordered protein tau transforms into cross-β-core containing fibrils. AFM imaging serves as a gentle probe of structures populated over the time course of tau fibrillization. Together, these assays help further elucidate the structural and mechanistic complexity inherent in tau fibril formation.

  19. The Scanning Optical Microscope.

    Science.gov (United States)

    Sheppard, C. J. R.

    1978-01-01

    Describes the principle of the scanning optical microscope and explains its advantages over the conventional microscope in the improvement of resolution and contrast, as well as the possibility of producing a picture from optical harmonies generated within the specimen.

  20. Microwave detected, microwave-optical double resonance of NH3, NH2D, NHD2, and ND3. I. Structure and force field of the à state

    Science.gov (United States)

    Henck, Steven A.; Mason, Martin A.; Yan, Wen-Bin; Lehmann, Kevin K.; Coy, Stephen L.

    1995-03-01

    Microwave detected, microwave-optical double resonance was used to record the à state electronic spectrum of NH3, NH2D, and NHD2 with both vibrational and rotational resolution. To investigate ND3 with the same resolution as we had with our hydrogen containing isotopomers, a strip-line cell was constructed allowing the simultaneous passage of radio-frequency and ultraviolet radiation. Rotational constants were obtained as a function of ν2 excitation and an à state equilibrium bond length was estimated at 1.055(8) Å. In addition, the harmonic force field for the à state has been experimentally determined. fhh, fαα-fαα', and frr were found to be 1.06(4) aJ/Å2, 0.25(2) aJ, and 4.9 aJ/Å2, respectively. This calculated harmonic force field predicts that the asymmetry observed in the NH3 24 band is due to a strong anharmonic interaction with the 43 level and the broad feature observed in the dispersed fluorescence spectrum previously assigned to the 11 band is more likely attributable to the 42 level.

  1. Resonance Frequency Breathing Biofeedback to Reduce Symptoms of Subthreshold PTSD with an Air Force Special Tactics Operator: A Case Study.

    Science.gov (United States)

    Petta, Lorene M

    2017-06-01

    The prevalence rates of post-traumatic stress disorder (PTSD) have been estimated to be several times higher in military populations compared to the national average. Special Tactics operators are a group that is more likely to avoid seeking psychological care due to the stigma and other consequences the diagnosis may have on their military careers. There is a need for more effective and less stigmatizing interventions to treat this population. Psychophysiological methods have been proven to be efficacious in treating PTSD, yet have received less attention as an adjunctive intervention. Resonance frequency (RF) biofeedback is a form of cardiorespiratory intervention that has shown promise as an effective treatment. The current case study examined the use of RF biofeedback in combination with other physiological and evidence-based methods as part of a comprehensive treatment approach. The client showed a significant drop from his initial scores on a screening assessment by the end of treatment, and demonstrated continued progress despite a 3-month break from the therapy. This author proposed that the synergistic effects of the multi-phased treatment approach contributed to the client's progress. Furthermore, a case was made for using multiple techniques when treating subthreshold PTSD and related symptoms within a treatment resistant population.

  2. Seismic estimates of turbulent diffusivity and evidence of nonlinear internal wave forcing by geometric resonance in the South China Sea

    Science.gov (United States)

    Fortin, W. F. J.; Holbrook, W. S.; Schmitt, R. W.

    2017-10-01

    The Luzon Passage generates some of the largest amplitude internal waves in the global ocean as the result of coupling between strong tides, strong stratification, and topography. These internal waves propagate into the South China Sea (SCS) and develop into soliton-like internal wave pulses that are observed by moored instruments and satellite backscatter data. Despite the observation of these waves, little is known of the mechanisms related to their evolution into nonlinear wave pulses. Using seismic data, we find evidence that the geometry of bathymetric conditions between the Heng-Chun and Lan-Yu ridges drive nonlinear internal wave pulse generation. We produce three seismic images and associated maps of turbulent diffusivity to investigate structure around the two ridges and into the SCS. We do not observe large amplitude soliton-like internal waves between the ridges, but do observe one outside the ridges, a finding in accord with the interpretation that wave pulses form due to geometrical resonance. Additionally, we find no evidence for lee wave activity above the ridges in either the seismic images or associated turbulence maps, suggesting an unlikelihood of hydraulic jump driven generation around the ridges. Our results show increased levels of turbulent diffusivity (1) in deep water below 1000 m, (2) associated with internal tide pulses, and (3) near the steep slopes of the Heng-Chun and Lan-Yu ridges as explored in this paper.

  3. Lumbo-pelvic joint protection against antigravity forces: motor control and segmental stiffness assessed with magnetic resonance imaging.

    Science.gov (United States)

    Richardson, C A; Hides, J A; Wilson, S; Stanton, W; Snijders, C J

    2004-07-01

    The antigravity muscles of the lumbo-pelvic region, especially transversus abdominis (TrA), are important for the protection and support of the weightbearing joints. Measures of TrA function (the response to the postural cue of drawing in the abdominal wall) have been developed and quantified using magnetic resonance imaging (MRI). Cross-sections through the trunk allowed muscle contraction as well as the large fascial attachments of the TrA to be visualized. The cross sectional area (CSA) of the deep musculo-fascial system was measured at rest and in the contracted state, using static images as well as a cine sequence. In this developmental study, MRI measures were undertaken on a small sample of low back pain (LBP) and non LBP subjects. Results demonstrated that, in non LBP subjects, the draw in action produced a symmetrical deep musculo-fascial "corset" which encircles the abdomen. This study demonstrated a difference in this "corset" measure between subjects with and without LBP. These measures may also prove useful to quantify the effect of unloading in bedrest and microgravity exposure.

  4. Of Mechanisms, Microscopes and Methyl isocyanate

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 3. Of Mechanisms, Microscopes and Methyl isocyanate. S Sriramachari Sujata Varadarajan. Face to Face Volume 13 Issue 3 March 2008 pp 292-306. Fulltext. Click here to view fulltext PDF. Permanent link:

  5. Wavelet Transform-A New Mathematical Microscope

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 3. Wavelet Transform - A New Mathematical Microscope. Sachin P Nanavati Prasanta K Panigrahi. General Article Volume 9 Issue 3 March 2004 pp 50-64. Fulltext. Click here to view fulltext PDF. Permanent link:

  6. Investigating the lignocellulosic composition during delignification using confocal raman spectroscopy, cross-polarization magic angle spinning carbon 13 - nuclear magnetic resonance (CP/MAS 13C- NMR) spectroscopy and atomic force microscopy

    CSIR Research Space (South Africa)

    Chunilall, Viren

    2012-03-01

    Full Text Available spectroscopy, Cross-Polarization Magic Angle Spinning Carbon 13 - Nuclear Magnetic Resonance (CP/MAS 13C-NMR) spectroscopy and Atomic Force Microscopy (AFM) in conjunction with image analysis. The confocal Raman results showed that there were differences...

  7. Magnetic resonance imaging showed no signs of overuse or permanent injury to the lumbar sacral spine during a Special Forces training course.

    Science.gov (United States)

    Aharony, Shachar; Milgrom, Charles; Wolf, Tamir; Barzilay, Yair; Applbaum, Yaakov H; Schindel, Yair; Finestone, Aharon; Liram, Nimrod

    2008-01-01

    Special Forces training is even more demanding than that of elite athletes. The training includes grueling physical activity and periods of sleep deprivation. The soldiers routinely carry heavy loads up to 40% of their body weight on their backs while running and marching for distances up to 90 km. Our purpose was to find out if Special Forces recruits are able to complete the preparatory Navy Seals training program without sustaining magnetic resonance imaging (MRI) signs of overuse or irreversible injury to their backs. Prospective cohort study. We performed MRI scans before and after 14 weeks of Navy Seals preparatory training course. Ten soldiers underwent MRI of their lumbar sacral spines and right knees before and after the completion of Navy Seals preparatory training. Physiologic measures. Lumbar sacral spine and knee MRI tests were performed before and after the training to identify changes in the spinal discs, facet joints, pars interarticularis, vertebral bodies, knee articular cartilage, ligaments, knee menisci, and the presence or absence of soft tissue and/or bone edema. We investigated the difference in spine and knee pathology before and after a 14-week Navy Seals preparatory training course by using MRI criteria. The recruits participating in the study were monitored for acute and overuse injuries every 3 to 4 weeks. Before the training, seven out of ten spine MRI scans were normal. Two showed small L5-S1 disc bulges, one of them with concomitant Scheuermann's disease. Another soldier's MRI showed L1-L4 mild Scheuermann's disease. Follow-up MRI showed no spinal changes. Before the training, one knee had a small lateral femoral condyle cartilage lesion. Nine of ten knees had prepatellar swelling, five had increased joint fluid, and two bone edema. Follow-up magnetic resonance imaging showed improvement in the prepatellar swelling in eight soldiers, no change in one soldier, and increased knee effusion and a new medial femoral condyle bone edema in

  8. Handbook of force transducers

    CERN Document Server

    Stefanescu, Dan Mihai

    2011-01-01

    Part I introduces the basic ""Principles and Methods of Force Measurement"" acording to a classification into a dozen of force transducers types: resistive, inductive, capacitive, piezoelectric, electromagnetic, electrodynamic, magnetoelastic, galvanomagnetic (Hall-effect), vibrating wires, (micro)resonators, acoustic and gyroscopic. Two special chapters refer to force balance techniques and to combined methods in force measurement. Part II discusses the ""(Strain Gauge) Force Transducers Components"", evolving from the classical force transducer to the digital / intelligent one, with the inco

  9. Cryogenic immersion microscope

    Science.gov (United States)

    Le Gros, Mark; Larabell, Carolyn A.

    2010-12-14

    A cryogenic immersion microscope whose objective lens is at least partially in contact with a liquid reservoir of a cryogenic liquid, in which reservoir a sample of interest is immersed is disclosed. When the cryogenic liquid has an index of refraction that reduces refraction at interfaces between the lens and the sample, overall resolution and image quality are improved. A combination of an immersion microscope and x-ray microscope, suitable for imaging at cryogenic temperatures is also disclosed.

  10. Analytical Electron Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — The Titan 80-300 is a transmission electron microscope (TEM) equipped with spectroscopic detectors to allow chemical, elemental, and other analytical measurements to...

  11. Binding kinetics of mutant p53R175H with wild type p53 and p63: A Surface Plasmon Resonance and Atomic Force Spectroscopy study.

    Science.gov (United States)

    Moscetti, Ilaria; Bizzarri, Anna Rita; Cannistraro, Salvatore

    2017-09-01

    The oncogenic mutant p53R175H, one of the most frequently occurring in human cancers and usually associated with poor prognosis and chemo resistance, can exert a dominant negative effect over p53 family members, namely wild type p53, p63 and p73, inhibiting their oncosuppressive function. Novel anticancer strategies based on drugs able to prevent the formation of complexes between p53R175H and the p53 family members call for a deeper knowledge on the molecular mechanisms of their interaction. To this aim, p53R175H/p63 and p53R175H/p53 complexes were investigated in vitro by using Surface Plasmon Resonance and Atomic Force Spectroscopy, two emerging and complementary techniques able to provide interaction kinetic information, in near physiological conditions and without any labelling. Both approaches show that p53R175H forms a very specific and highly stable bimolecular complex with both p63 and p53; with these interactions being characterized by a very high affinity with equilibrium dissociation constant, KD, of about 10-9M. These kinetics results, discussed also in connection with those previously reported for the interaction of p53R175H with p73, could inspire the design of suitable anticancer drugs able to antagonize the interaction of p53R175H with the p53 family members, by restoring then their anti-tumour function. Copyright © 2017. Published by Elsevier B.V.

  12. Near field plasmon and force microscopy

    NARCIS (Netherlands)

    de Hollander, R.B.G.; van Hulst, N.F.; Kooyman, R.P.H.

    1995-01-01

    A scanning plasmon near field optical microscope (SPNM) is presented which combines a conventional far field surface plasmon microscope with a stand-alone atomic force microscope (AFM). Near field plasmon and force images are recorded simultaneously both with a lateral resolution limited by the

  13. Mailing microscope slides

    Science.gov (United States)

    Many insects feed agriculturally important crops, trees, and ornamental plants and cause millions of dollars of damage annually. Identification for some of these require the preparation of a microscope slide for examination. There are times when a microscope slide may need to be sent away to a speci...

  14. [Microscopic colitis: update 2014].

    Science.gov (United States)

    Burgmann, Konstantin; Fraga, Montserrat; Schoepfer, Alain M; Yun, Pu

    2014-09-03

    Microscopic colitis, which includes lymphocytic colitis and collagenous colitis, represents a frequent cause of chronic watery diarrhea especially in the elderly population. Several medications, such as nonsteroidal antiinflammatory drugs, proton pump inhibitors or antidepressants, as well as cigarette smoking have been recognized as risk factors for microscopic colitis. The diagnosis of microscopic colitis is based on a macroscopically normal ileo-colonoscopy and several biopsies from the entire colon, which demonstrate the pathognomonic histopathologic findings. Therapy is mainly based on the use of budesonide. Other medications, such as mesalazine, cholestyramine and bismuth, have been evaluated as well but the evidence is less solid.

  15. Binding of Amphipathic Cell Penetrating Peptide p28 to Wild Type and Mutated p53 as studied by Raman, Atomic Force and Surface Plasmon Resonance spectroscopies.

    Science.gov (United States)

    Signorelli, Sara; Santini, Simona; Yamada, Tohru; Bizzarri, Anna Rita; Beattie, Craig W; Cannistraro, Salvatore

    2017-04-01

    Mutations within the DNA binding domain (DBD) of the tumor suppressor p53 are found in >50% of human cancers and may significantly modify p53 secondary structure impairing its function. p28, an amphipathic cell-penetrating peptide, binds to the DBD through hydrophobic interaction and induces a posttranslational increase in wildtype and mutant p53 restoring functionality. We use mutation analyses to explore which elements of secondary structure may be critical to p28 binding. Molecular modeling, Raman spectroscopy, Atomic Force Spectroscopy (AFS) and Surface Plasmon Resonance (SPR) were used to identify which secondary structure of site-directed and naturally occurring mutant DBDs are potentially altered by discrete changes in hydrophobicity and the molecular interaction with p28. We show that specific point mutations that alter hydrophobicity within non-mutable and mutable regions of the p53 DBD alter specific secondary structures. The affinity of p28 was positively correlated with the β-sheet content of a mutant DBD, and reduced by an increase in unstructured or random coil that resulted from a loss in hydrophobicity and redistribution of surface charge. These results help refine our knowledge of how mutations within p53-DBD alter secondary structure and provide insight on how potential structural alterations in p28 or similar molecules improve their ability to restore p53 function. Raman spectroscopy, AFS, SPR and computational modeling are useful approaches to characterize how mutations within the p53DBD potentially affect secondary structure and identify those structural elements prone to influence the binding affinity of agents designed to increase the functionality of p53. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Robert Feulgen Prize Lecture. Laser tweezers and multiphoton microscopes in life sciences.

    Science.gov (United States)

    König, K

    2000-08-01

    Near infrared (NIR) laser microscopy enables optical micromanipulation, piconewton force determination, and sensitive fluorescence studies by laser tweezers. Otherwise, fluorescence images with high spatial and temporal resolution of living cells and tissues can be obtained via non-resonant fluorophore excitation with multiphoton NIR laser scanning microscopes. Furthermore, NIR femtosecond laser pulses at TW/cm2 intensities can be used to realize non-invasive contact-free surgery of nanometer-sized structures within living cells and tissues. Applications of these novel versatile NIR laser-based tools for the determination of motility forces, coenzyme and chlorophyll imaging, three-dimensional multigene detection, non-invasive optical sectioning of tissues ("optical biopsy"), functional protein imaging, and nanosurgery of chromosomes are described.

  17. Scanning Auger Electron Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — A JEOL model 7830F field emission source, scanning Auger microscope.Specifications / Capabilities:Ultra-high vacuum (UHV), electron gun range from 0.1 kV to 25 kV,...

  18. Microscopic colitis: a review.

    Science.gov (United States)

    Farrukh, A; Mayberry, J F

    2014-12-01

    In recent years, microscopic colitis has been increasingly diagnosed. This review was carried out to evaluate demographic factors for microscopic colitis and to perform a systematic assessment of available treatment options. Relevant publications up to December 2013 were identified following searches of PubMed and Google Scholar using the key words 'microscopic colitis', 'collagenous colitis' and 'lymphocytic colitis'. Two-hundred and forty-eight articles were identified. The term microscopic colitis includes lymphocytic colitis and collagenous colitis. Both have common clinical symptoms but are well defined histopathologically. The clinical course is usually benign, but serious complications, including death, may occur. A peak incidence from 60 to 70 years of age with a female preponderance is observed. Although most cases are idiopathic, associations with autoimmune disorders, such as coeliac disease and hypothyroidism, as well as with exposure to nonsteroidal anti-inflammatory drugs and proton-pump inhibitors, have been observed. The incidence and prevalence of microscopic colitis is rising and good-quality epidemiological research is needed. Treatment is currently largely based on anecdotal evidence and on results from limited clinical trials of budesonide. Long-term follow-up of these patients is not well established. The review synthesizes work on the definition of microscopic colitis and the relationship between collagenous and lymphocytic colitis. It reviews the international epidemiology and work on aetiology. In addition, it critically considers the efficacy of a range of treatments. Colorectal Disease © 2014 The Association of Coloproctology of Great Britain and Ireland.

  19. Piezoelectric Motor Using In-Plane Orthogonal Resonance Modes of an Octagonal Plate

    Directory of Open Access Journals (Sweden)

    Karl Spanner

    2018-01-01

    Full Text Available Piezoelectric motors use the inverse piezoelectric effect, where microscopically small periodical displacements are transferred to continuous or stepping rotary or linear movements through frictional coupling between a displacement generator (stator and a moving (slider element. Although many piezoelectric motor designs have various drive and operating principles, microscopic displacements at the interface of a stator and a slider can have two components: tangential and normal. The displacement in the tangential direction has a corresponding force working against the friction force. The function of the displacement in the normal direction is to increase or decrease friction force between a stator and a slider. Simply, the generated force alters the friction force due to a displacement in the normal direction, and the force creates movement due to a displacement in the tangential direction. In this paper, we first describe how the two types of microscopic tangential and normal displacements at the interface are combined in the structures of different piezoelectric motors. We then present a new resonance-drive type piezoelectric motor, where an octagonal plate, with two eyelets in the middle of the two main surfaces, is used as the stator. Metallization electrodes divide top and bottom surfaces into two equal regions orthogonally, and the two driving signals are applied between the surfaces of the top and the bottom electrodes. By controlling the magnitude, frequency and phase shift of the driving signals, microscopic tangential and normal displacements in almost any form can be generated. Independently controlled microscopic tangential and normal displacements at the interface of the stator and the slider make the motor have lower speed–control input (driving voltage nonlinearity. A test linear motor was built by using an octagonal piezoelectric plate. It has a length of 25.0 mm (the distance between any of two parallel side surfaces and a

  20. Designs for a quantum electron microscope.

    Science.gov (United States)

    Kruit, P; Hobbs, R G; Kim, C-S; Yang, Y; Manfrinato, V R; Hammer, J; Thomas, S; Weber, P; Klopfer, B; Kohstall, C; Juffmann, T; Kasevich, M A; Hommelhoff, P; Berggren, K K

    2016-05-01

    One of the astounding consequences of quantum mechanics is that it allows the detection of a target using an incident probe, with only a low probability of interaction of the probe and the target. This 'quantum weirdness' could be applied in the field of electron microscopy to generate images of beam-sensitive specimens with substantially reduced damage to the specimen. A reduction of beam-induced damage to specimens is especially of great importance if it can enable imaging of biological specimens with atomic resolution. Following a recent suggestion that interaction-free measurements are possible with electrons, we now analyze the difficulties of actually building an atomic resolution interaction-free electron microscope, or "quantum electron microscope". A quantum electron microscope would require a number of unique components not found in conventional transmission electron microscopes. These components include a coherent electron beam-splitter or two-state-coupler, and a resonator structure to allow each electron to interrogate the specimen multiple times, thus supporting high success probabilities for interaction-free detection of the specimen. Different system designs are presented here, which are based on four different choices of two-state-couplers: a thin crystal, a grating mirror, a standing light wave and an electro-dynamical pseudopotential. Challenges for the detailed electron optical design are identified as future directions for development. While it is concluded that it should be possible to build an atomic resolution quantum electron microscope, we have also identified a number of hurdles to the development of such a microscope and further theoretical investigations that will be required to enable a complete interpretation of the images produced by such a microscope. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  1. Modelling of the MICROSCOPE Mission

    Science.gov (United States)

    Bremer, Stefanie; List, Meike

    2010-03-01

    The French space mission MICROSCOPE aims at testing the Equivalence Principle (EP) up to an accuracy of 10-15. The experiment will be carried out on a satellite which is developed and produced within the CNES Myriade series. The measuring accuracy will be achieved by means of two high-precision capacitive differential accelerometers that are built by the French institute ONERA, see Touboul and Rodrigues (Class. Quantum Gravity 18:2487-2498, 2001). At ZARM, which is a member of the science team, the data evaluation process is prepared. Therefore, a comprehensive simulation of the real system including the science signal and all error sources is built for the development and testing of data reduction and data analysis algorithms to extract the EP violation signal. Currently, the ZARM Drag-Free simulator, a tool to support mission modelling, is adapted for the MICROSCOPE mission in order to simulate test mass and satellite dynamics. Models of environmental disturbances like solar radiation pressure are considered, also. Additionally, detailed modelling of the on-board capacitive sensors is done. The actual status of the mission modelling will be presented. Particularly, the modelling of disturbances forces will be discussed in detail.

  2. Familial Microscopic Colitis

    Directory of Open Access Journals (Sweden)

    Ayman Assad Abdo

    2001-01-01

    Full Text Available Collagenous and lymphocytic colitis are two inflammatory conditions of the colon that are often collectively referred to as microscopic colitis. The present report describes what is believed to be the third published case of familial microscopic colitis. A 55-year-old woman who suffered from chronic diarrhea was diagnosed with lymphocytic colitis on colonic biopsy. Subsequently, her 36-year-old daughter was diagnosed with collagenous colitis. The familial occurrence of these diseases may support an immunological hypothesis for their etiology. In addition, it supports the assumption that collagenous and lymphocytic colitis are two manifestations of the same disease process rather than two completely separate entities. The familial tendency of this disease may make a case for early colonoscopy and biopsy in relatives of patients diagnosed with microscopic colitis if they present with suggestive symptoms.

  3. Rapid screening and diagnosis of various cancers from human voice using Bi-Digital O-Ring Test resonance phenomenon between 2 identical substances i.e. between microscope slide of specific cancer tissue & cancer information in the sound of human voice, and detection of myocardial damage & infection from human voice.

    Science.gov (United States)

    Omura, Yoshiaki

    2007-01-01

    Since 1982, the author has been successfully using Bi-Digital O-Ring Test (BDORT) electro-magnetic resonance phenomenon between 2 identical substances; i.e. between specific cancer (in vivo) of a patient and a microscope slide of identical cancer tissue to detect cancers at a very early stage. Since 2000, the author has found that when BDORT is performed while an individual with a malignant tumor is talking, BDORT became (-1 approximately -10) in 94% of 200 cases and the number of openings (-) is approximately proportional to the degree of abnormality up to -10. Thus, cancer can be screened from voice within 1 min., without any instruments. Also, when cancer-free persons hold slides of cancer tissue or 10ng or higher Oncogene C-fos Ab2 or Integrin alpha5beta1 while talking over a short or long distance, BDORT always opens. To identify the type of the patient's malignancy, if BDORT is performed by an examiner holding a microscope slide of cancer tissue identical to the patient's cancer, characteristic strong BDORT resonance phenomenon appears with opening of all O-Rings formed between thumb and other fingers. When patients with myocardial infarct or various infections speak, no O-Rings open without holding identical pathological substances. Thus, it is possible to detect any type of malignancy from the voice, as long as a set of about 35 different tumor tissue slides is available. Based on these new findings, the author concluded that the voice of an individual with a malignancy carries information about the amount and structure of molecules present in malignant tissue.

  4. Scanning probe microscopes go video rate and beyond

    Science.gov (United States)

    Rost, M. J.; Crama, L.; Schakel, P.; van Tol, E.; van Velzen-Williams, G. B. E. M.; Overgauw, C. F.; ter Horst, H.; Dekker, H.; Okhuijsen, B.; Seynen, M.; Vijftigschild, A.; Han, P.; Katan, A. J.; Schoots, K.; Schumm, R.; van Loo, W.; Oosterkamp, T. H.; Frenken, J. W. M.

    2005-05-01

    In this article we introduce a, video-rate, control system that can be used with any type of scanning probe microscope, and that allows frame rates up to 200images/s. These electronics are capable of measuring in a fast, completely analog mode as well as in the more conventional digital mode. The latter allows measurements at low speeds and options, such as, e.g., atom manipulation, current-voltage spectroscopy, or force-distance curves. For scanning tunneling microscope (STM) application we implemented a hybrid mode between the well-known constant-height and constant-current modes. This hybrid mode not only increases the maximum speed at which the surface can be imaged, but also improves the resolution at lower speeds. Acceptable image quality at high speeds could only be obtained by pushing the performance of each individual part of the electronics to its limit: we developed a preamplifier with a bandwidth of 600kHz, a feedback electronics with a bandwidth of 1MHz, a home-built bus structure for the fast data transfer, fast analog to digital converters, and low-noise drivers. Future improvements and extensions to the control electronics can be realized easily and quickly, because of its open architecture with its modular plug-in units. In the second part of this article we show our high-speed results. The ultrahigh vacuum application of these control electronics on our (UHV)-STM enabled imaging speeds up to 0.3mm/s, while still obtaining atomic step resolution. At high frame rates, the images suffered from noticeable distortions, which we have been able to analyze by virtue of the unique access to the error (dZ) signal. The distortions have all been associated with mechanical resonances in the scan head of the UHV-STM. In order to reduce such resonance effects, we have designed and built a scan head with high resonance frequencies (⩾64kHz), especially for the purpose of testing the fast electronics. Using this scanner we have reached video-rate imaging speeds

  5. Scanning transmission electron microscope

    NARCIS (Netherlands)

    Kruit, P.

    2006-01-01

    The invention relates to a scanning transmission electron microscope comprising an electron source, an electron accelerator and deflection means for directing electrons emitted by the electron source at an object to be examined, and in addition a detector for detecting electrons coming from the

  6. Microscope on Mars

    Science.gov (United States)

    2004-01-01

    This image taken at Meridiani Planum, Mars by the panoramic camera on the Mars Exploration Rover Opportunity shows the rover's microscopic imager (circular device in center), located on its instrument deployment device, or 'arm.' The image was acquired on the ninth martian day or sol of the rover's mission.

  7. MICROSCOPIC, PHYSICOCHEMICAL AND CHROMATOGRAPHIC ...

    African Journals Online (AJOL)

    Peters

    sulphated ash 19.6%, water-soluble ash 6.8%, alcohol-soluble extractive 9.5% and water-soluble extractive 24.1%. Chromatographic fingerprints of ... chloral hydrate, mounted in dilute glycerol on a microscope slide and viewed at different ... was washed off in water and the sample mounted on a slide with glycerin.

  8. Terahertz scanning probe microscope

    NARCIS (Netherlands)

    Klapwijk, T.M.

    2014-01-01

    The invention provides aterahertz scanning probe microscope setup comprising (i) a terahertz radiation source configured to generate terahertz radiation; (ii) a terahertz lens configured to receive at least part of the terahertz radiation from the terahertz radiation source; (iii) a cantilever unit

  9. SPM: Scanning positron microscope

    Directory of Open Access Journals (Sweden)

    Marcel Dickmann

    2015-08-01

    Full Text Available The Munich scanning positron microscope, operated by the Universität der Bundeswehr München and the Technische Universität München, located at NEPOMUC, permits positron lifetime measurements with a lateral resolution in the µm range and within an energy range of 1 – 20 keV.

  10. Ion photon emission microscope

    Science.gov (United States)

    Doyle, Barney L.

    2003-04-22

    An ion beam analysis system that creates microscopic multidimensional image maps of the effects of high energy ions from an unfocussed source upon a sample by correlating the exact entry point of an ion into a sample by projection imaging of the ion-induced photons emitted at that point with a signal from a detector that measures the interaction of that ion within the sample. The emitted photons are collected in the lens system of a conventional optical microscope, and projected on the image plane of a high resolution single photon position sensitive detector. Position signals from this photon detector are then correlated in time with electrical effects, including the malfunction of digital circuits, detected within the sample that were caused by the individual ion that created these photons initially.

  11. Microscopic approach to polaritons

    DEFF Research Database (Denmark)

    Skettrup, Torben

    1981-01-01

    The interaction between excitons and light has been investigated in detail. The perturbational approach turns out to be invalid. However, an exact solution can be obtained directly from the Schrödinger equation for a fixed light field. This solution corresponds to a nonlinear optical response...... contrary to experimental experience. In order to remove this absurdity the semiclassical approach must be abandoned and the electromagnetic field quantized. A simple microscopic polariton model is then derived. From this the wave function for the interacting exciton-photon complex is obtained...... of light of the crystal. The introduction of damping smears out the excitonic spectra. The wave function of the polariton, however, turns out to be very independent of damping up to large damping values. Finally, this simplified microscopic polariton model is compared with the exact solutions obtained...

  12. Scanning transmission electron microscope

    OpenAIRE

    Kruit, P.

    2006-01-01

    The invention relates to a scanning transmission electron microscope comprising an electron source, an electron accelerator and deflection means for directing electrons emitted by the electron source at an object to be examined, and in addition a detector for detecting electrons coming from the object and, connected to the detector, a device for processing the detected electrons so as to form an object image, wherein a beam splitter is provided for dividing the electron beam from the electron...

  13. Color Laser Microscope

    Science.gov (United States)

    Awamura, D.; Ode, T.; Yonezawa, M.

    1987-04-01

    A color laser microscope utilizing a new color laser imaging system has been developed for the visual inspection of semiconductors. The light source, produced by three lasers (Red; He-Ne, Green; Ar, Blue; He-Cd), is deflected horizontally by an AOD (Acoustic Optical Deflector) and vertically by a vibration mirror. The laser beam is focused in a small spot which is scanned over the sample at high speed. The light reflected back from the sample is reformed to contain linear information by returning to the original vibration mirror. The linear light is guided to the CCD image sensor where it is converted into a video signal. Individual CCD image sensors are used for each of the three R, G, or B color image signals. The confocal optical system with its laser light source yields a color TV monitor image with no flaring and a much sharper resolution than that of the conventional optical microscope. The AOD makes possible a high speed laser scan and a NTSC or PAL TV video signal is produced in real time without any video memory. Since the light source is composed of R, G, and B laser beams, color separation superior to that of white light illumination is achieved. Because of the photometric linearity of the image detector, the R, G, and B outputs of the system are most suitably used for hue analysis. The CCD linear image sensors in the optical system produce no geometrical distortion, and good color registration is available principally. The output signal can be used for high accuracy line width measuring. The many features of the color laser microscope make it ideally suited for the visual inspection of semiconductor processing. A number of these systems have already been installed in such a capacity. The Color Laser Microscope can also be a very useful tool for the fields of material engineering and biotechnology.

  14. RESONANT AMPLIFICATION OF TURBULENCE BY THE BLAST WAVES

    Energy Technology Data Exchange (ETDEWEB)

    Zankovich, A. M.; Kovalenko, I. G., E-mail: ilya.g.kovalenko@gmail.com [Physicotechnical Institute, Volgograd State University, Volgograd 400062 (Russian Federation)

    2015-02-10

    We discuss the idea of whether spherical blast waves can amplify by a nonlocal resonant hydrodynamic mechanism inhomogeneities formed by turbulence or phase segregation in the interstellar medium. We consider the problem of a blast-wave-turbulence interaction in the Linear Interaction Approximation. Mathematically, this is an eigenvalue problem for finding the structure and amplitude of eigenfunctions describing the response of the shock-wave flow to forced oscillations by external perturbations in the ambient interstellar medium. Linear analysis shows that the blast wave can amplify density and vorticity perturbations for a wide range of length scales with amplification coefficients of up to 20, with increasing amplification the larger the length. There also exist resonant harmonics for which the gain becomes formally infinite in the linear approximation. Their orbital wavenumbers are within the range of macro- (l ∼ 1), meso- (l ∼ 20), and microscopic (l > 200) scales. Since the resonance width is narrow (typically, Δl < 1), resonance should select and amplify discrete isolated harmonics. We speculate on a possible explanation of an observed regular filamentary structure of regularly shaped round supernova remnants such as SNR 1572, 1006, or 0509-67.5. Resonant mesoscales found (l ≈ 18) are surprisingly close to the observed scales (l ≈ 15) of ripples in the shell's surface of SNR 0509-67.5.

  15. Photography with a Microscope

    Science.gov (United States)

    Rost, Fred; Oldfield, Ron

    2000-03-01

    This beautifully illustrated book describes the methods used to record images viewed through a microscope. The text describes the principles and practices of photomicrography, and is written for all who take photomicrographs, beginners and/or experienced practitioners. The authors describe techniques that may be applied to many disciplines for teaching, research, archives, or pleasure. The book includes chapters on standard photography, modern digital techniques, methods for improving contrast, and a short chapter on drawing. In addition to its value as a work of reference, the authors' clear, didactic style makes this book suitable as a textbook for courses in photomicrography and/or elementary light microscopy.

  16. Solid state optical microscope

    Science.gov (United States)

    Young, Ian T.

    1983-01-01

    A solid state optical microscope wherein wide-field and high-resolution images of an object are produced at a rapid rate by utilizing conventional optics with a charge-coupled photodiode array. A galvanometer scanning mirror, for scanning in one of two orthogonal directions is provided, while the charge-coupled photodiode array scans in the other orthogonal direction. Illumination light from the object is incident upon the photodiodes, creating packets of electrons (signals) which are representative of the illuminated object. The signals are then processed, stored in a memory, and finally displayed as a video signal.

  17. Athena Microscopic Imager investigation

    OpenAIRE

    Herkenhoff, K. E.

    2003-01-01

    The Athena science payload on the Mars Exploration Rovers (MER) includes the Microscopic Imager (MI). The MI is a fixed-focus camera mounted on the end of an extendable instrument arm, the Instrument Deployment Device (IDD). The MI was designed to acquire images at a spatial resolution of 30 microns/pixel over a broad spectral range (400–700 nm). The MI uses the same electronics design as the other MER cameras but has optics that yield a field of view of 31 31 mm across a 1024...

  18. Evaluation of a completely robotized neurosurgical operating microscope.

    Science.gov (United States)

    Kantelhardt, Sven R; Finke, Markus; Schweikard, Achim; Giese, Alf

    2013-01-01

    Operating microscopes are essential for most neurosurgical procedures. Modern robot-assisted controls offer new possibilities, combining the advantages of conventional and automated systems. We evaluated the prototype of a completely robotized operating microscope with an integrated optical coherence tomography module. A standard operating microscope was fitted with motors and control instruments, with the manual control mode and balance preserved. In the robot mode, the microscope was steered by a remote control that could be fixed to a surgical instrument. External encoders and accelerometers tracked microscope movements. The microscope was additionally fitted with an optical coherence tomography-scanning module. The robotized microscope was tested on model systems. It could be freely positioned, without forcing the surgeon to take the hands from the instruments or avert the eyes from the oculars. Positioning error was about 1 mm, and vibration faded in 1 second. Tracking of microscope movements, combined with an autofocus function, allowed determination of the focus position within the 3-dimensional space. This constituted a second loop of navigation independent from conventional infrared reflector-based techniques. In the robot mode, automated optical coherence tomography scanning of large surface areas was feasible. The prototype of a robotized optical coherence tomography-integrated operating microscope combines the advantages of a conventional manually controlled operating microscope with a remote-controlled positioning aid and a self-navigating microscope system that performs automated positioning tasks such as surface scans. This demonstrates that, in the future, operating microscopes may be used to acquire intraoperative spatial data, volume changes, and structural data of brain or brain tumor tissue.

  19. Enhanced intermolecular forces in supramolecular polymer nanocomposites

    Directory of Open Access Journals (Sweden)

    F. Lin

    2017-09-01

    Full Text Available Ureido-pyrimidone (Upy can dimerize in a self-complementary array of quadruple hydrogen bonds. In this paper, supramolecular polymer composites were prepared by blending Upy functionalized nanosilica with Upy end-capped polycarbonatediol. Surface characteristics of Upy functionalized nanosilica and influences of supramolecular forces on interfacial binding were researched. Fourier transform infrared spectroscopy (FTIR, Nuclear magnetic resonance (NMR and Gel permeation chromatography (GPC were used to characterize the synthesized molecules. Grafting ratio of Upy segments on the surface of nanosilica was analysed by Thermogravimetic analysis (TGA. Hydrophobicity and morphology of Upy modified nanosilica were analysed by Contact angle tester and Scanning electron microscope (SEM. Furthermore, dynamic thermo mechanical properties, mechanical properties and distribution of nanosilica in supramolecular polymer composites were also researched. Compared with the matrix resin, tensile stress and young's modulus of supramolecular polymer composites containing 5 wt% modified nanosilica were increased by 292 and 198% respectively.

  20. Comparing the photocatalytic activity of TiO2 at macro- and microscopic scales

    DEFF Research Database (Denmark)

    Torras-Rosell, Antoni; Johannsen, Sabrina Rostgaard; Dirscherl, Kai

    2016-01-01

    This study focuses on the characterization of photocatalytic TiO2 coatings using Kelvin probe force microscopy. While most photocatalytic experiments are carried out at a macroscopic scale, Kelvin probe force microscopy is a microscopic technique that is surface sensitive. In order to link....... The photocatalytic properties of TiO2 at macro- and microscopic scales are investigated by comparing photocatalytic degradation of acetone and electrochemical experiments to Kelvin probe force microscopy. The good agreement between the macro- and microscopic experiments suggests that Kelvin probe force microscopy...... can be a valuable tool towards the understanding, standardization and design of TiO2-based solutions in photocatalytic applications....

  1. Laser Scanning Fluorescence Microscope

    Science.gov (United States)

    Hansen, Eric W.; Zelten, J. Peter; Wiseman, Benjamin A.

    1988-06-01

    We report on the development of a laser scanning fluorescence microscope possessing several features which facilitate its application to biological and biophysical analyses in living cells. It is built around a standard inverted microscope stand, enabling the use of standard optics, micromanipulation apparatus, and conventional (including video) microscopy in conjunction with laser scanning. The beam is scanned across the specimen by a pair of galvanometer-mounted mirrors, driven by a programmable controller which can operate in three modes: full raster scan, region of interest, and random-access. A full 512x512 pixel image can be acquired in one second. In region of interest mode, several subareas of the field can be selected for more rapid or detailed analysis. For those cases where the time scale of the observed phenomenon precludes full-field imaging, or where a full-field image is unnecessary, the random access mode enables an arbitrary pattern of isolated points to be selected and rapidly sequenced through. Via a graphical user interface implemented on the system's host computer, a user will be able to take a scout image either with video or a full-field laser scan, select regions or points on the scout image with a mouse, and set up experimental parameters such as detector integration times with a window-style menu. The instrument is designed to be a flexible testbed for investigating new techniques, without compromising its utility as a tool for biological research.

  2. Electron microscope phase enhancement

    Science.gov (United States)

    Jin, Jian; Glaeser, Robert M.

    2010-06-15

    A microfabricated electron phase shift element is used for modifying the phase characteristics of an electron beam passing though its center aperture, while not affecting the more divergent portion of an incident beam to selectively provide a ninety-degree phase shift to the unscattered beam in the back focal plan of the objective lens, in order to realize Zernike-type, in-focus phase contrast in an electron microscope. One application of the element is to increase the contrast of an electron microscope for viewing weakly scattering samples while in focus. Typical weakly scattering samples include biological samples such as macromolecules, or perhaps cells. Preliminary experimental images demonstrate that these devices do apply a ninety degree phase shift as expected. Electrostatic calculations have been used to determine that fringing fields in the region of the scattered electron beams will cause a negligible phase shift as long as the ratio of electrode length to the transverse feature-size aperture is about 5:1. Calculations are underway to determine the feasibility of aspect smaller aspect ratios of about 3:1 and about 2:1.

  3. Microscopic colitis. A review.

    Science.gov (United States)

    Brown, William R; Tayal, Shalini

    2013-06-01

    Microscopic colitis (MC) is characterized by a triad of watery diarrhea, usually normal colonoscopic findings and typical microscopic findings. Two distinct histological forms of MC have been defined: lymphocytic colitis and collagenous colitis, but overlapping features may be present. The incidence of MC appears to be rising and in some countries it may account for as many as 10-20% of patients with non-bloody watery diarrhea. The cause of MC remains unknown and is likely to be multifactorial. The pathogenesis is poorly defined, and numerous immunological abnormalities have been reported. MC is commonly associated with autoimmune diseases including celiac disease. Use of various medications, most notably non-steroidal anti-inflammatory agents and proton pump inhibitors, have been etiologically implicated but not firmly established as causative. In imperfect trials several agents have been reported to be effective in the treatment of MC; budesonide is the best studied and evidence supporting its effectiveness is the most persuasive. In cases of otherwise unexplained watery, non-bloody diarrhea, MC should be considered and colonic biopsied specimens should be taken of normal-appearing mucosa. © 2013 The Authors. Journal of Digestive Diseases © 2013 Wiley Publishing Asia Pty Ltd and Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine.

  4. Resonant Operation of a Micro-Newton Thrust Stand

    National Research Council Canada - National Science Library

    Lake, James

    2003-01-01

    .... Force is applied resonantly with oscillation each half period. The calibration method utilizes an electromagnet to pick up and drop masses to apply a known force in the same resonant fashion as thruster operation...

  5. Resonant Operation of a Micro-Newton Thrust Stand

    National Research Council Canada - National Science Library

    Adkison, Paul

    2002-01-01

    .... Force is applied resonantly with oscillation each half period. The calibration method utilizes an electromagnet to pick up and drop masses to apply a known force in the same resonant fashion as thruster operation...

  6. Method to characterize the vibrational response of a beetle type scanning tunneling microscope

    Energy Technology Data Exchange (ETDEWEB)

    Behler, S.; Rose, M.K.; Ogletree, D.F.; Salmeron, M. [Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States)

    1997-01-01

    We describe a method for analyzing the external vibrations and intrinsic mechanical resonances affecting scanning probe microscopes by using the microscope as an accelerometer. We show that clear correlations can be established between the frequencies of mechanical vibrational modes and the frequencies of peaks in the tunnel current noise power spectrum. When this method is applied to our {open_quotes}beetle{close_quotes} type scanning tunneling microscope (STM), we find unexpected low frequency {open_quotes}rattling resonances{close_quotes} in the 500{endash}1700 Hz range that depend on the exact lateral position of the STM, in addition to the expected mechanical resonances of the STM above 4 kHz which are in good agreement with theoretical estimates. We believe that these rattling resonances may be a general problem for scanning probe microscopes that use some type of kinetic motion for coarse positioning. {copyright} {ital 1997 American Institute of Physics.}

  7. Atomic force microscopic comparison of remineralization with casein-phosphopeptide amorphous calcium phosphate paste, acidulated phosphate fluoride gel and iron supplement in primary and permanent teeth: An in-vitro study.

    Science.gov (United States)

    Agrawal, Nikita; Shashikiran, N D; Singla, Shilpy; Ravi, K S; Kulkarni, Vinaya Kumar

    2014-01-01

    Demineralization of tooth by erosion is caused by frequent contact between the tooth surface and acids present in soft drinks. The present study objective was to evaluate the remineralization potential of casein-phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste, 1.23% acidulated phosphate fluoride (APF) gel and iron supplement on dental erosion by soft drinks in human primary and permanent enamel using atomic force microscopy (AFM). Specimens were made from extracted 15 primary and 15 permanent teeth which were randomly divided into three treatment groups: CPP-ACP paste, APF gel and iron supplement. AFM was used for baseline readings followed by demineralization and remineralization cycle. Almost all group of samples showed remineralization that is a reduction in surface roughness which was higher with CPP-ACP paste. Statistical analysis was performed using by one-way ANOVA and Mann-Whitney U-test with P paste is effective on preventing dental erosion from soft drinks.

  8. Principles and applications of force spectroscopy using atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Kyu; Kim, Woong; Park, Joon Won [Dept. of Chemistry, Pohang University of Science and Technology, Pohang (Korea, Republic of)

    2016-12-15

    Single-molecule force spectroscopy is a powerful technique for addressing single molecules. Unseen structures and dynamics of molecules have been elucidated using force spectroscopy. Atomic force microscope (AFM)-based force spectroscopy studies have provided picoNewton force resolution, subnanometer spatial resolution, stiffness of substrates, elasticity of polymers, and thermodynamics and kinetics of single-molecular interactions. In addition, AFM has enabled mapping the distribution of individual molecules in situ, and the quantification of single molecules has been made possible without modification or labeling. In this review, we describe the basic principles, sample preparation, data analysis, and applications of AFM-based force spectroscopy and its future.

  9. Hexagonal quartz resonator

    Science.gov (United States)

    Peters, Roswell D. M.

    1982-01-01

    A generally flat, relatively thin AT-cut piezoelectric resonator element structured to minimize the force-frequency effect when mounted and energized in a housing. The resonator is in the form of an equilateral hexagon with the X crystallographic axis of the crystal passing through one set of opposing corners with mounting being effected at an adjacent set of corners respectively .+-.60.degree. away from the X axis which thereby results in a substantially zero frequency shift of the operating frequency.

  10. Anisotropic contrast optical microscope.

    Science.gov (United States)

    Peev, D; Hofmann, T; Kananizadeh, N; Beeram, S; Rodriguez, E; Wimer, S; Rodenhausen, K B; Herzinger, C M; Kasputis, T; Pfaunmiller, E; Nguyen, A; Korlacki, R; Pannier, A; Li, Y; Schubert, E; Hage, D; Schubert, M

    2016-11-01

    An optical microscope is described that reveals contrast in the Mueller matrix images of a thin, transparent, or semi-transparent specimen located within an anisotropic object plane (anisotropic filter). The specimen changes the anisotropy of the filter and thereby produces contrast within the Mueller matrix images. Here we use an anisotropic filter composed of a semi-transparent, nanostructured thin film with sub-wavelength thickness placed within the object plane. The sample is illuminated as in common optical microscopy but the light is modulated in its polarization using combinations of linear polarizers and phase plate (compensator) to control and analyze the state of polarization. Direct generalized ellipsometry data analysis approaches permit extraction of fundamental Mueller matrix object plane images dispensing with the need of Fourier expansion methods. Generalized ellipsometry model approaches are used for quantitative image analyses. These images are obtained from sets of multiple images obtained under various polarizer, analyzer, and compensator settings. Up to 16 independent Mueller matrix images can be obtained, while our current setup is limited to 11 images normalized by the unpolarized intensity. We demonstrate the anisotropic contrast optical microscope by measuring lithographically defined micro-patterned anisotropic filters, and we quantify the adsorption of an organic self-assembled monolayer film onto the anisotropic filter. Comparison with an isotropic glass slide demonstrates the image enhancement obtained by our method over microscopy without the use of an anisotropic filter. In our current instrument, we estimate the limit of detection for organic volumetric mass within the object plane of ≈49 fg within ≈7 × 7 μm2 object surface area. Compared to a quartz crystal microbalance with dissipation instrumentation, where contemporary limits require a total load of ≈500 pg for detection, the instrumentation demonstrated here improves

  11. THz wave emission microscope

    Science.gov (United States)

    Yuan, Tao

    Sensing and imaging using Terahertz (THz) radiation has attracted more and more interest in the last two decades thanks to the abundant material 'finger prints' in the THz frequency range. The low photon energy also makes THz radiation an attractive tool for nondestructive evaluation of materials and devices, biomedical applications, security checks and explosive screening. Due to the long wavelength, the far-field THz wave optical systems have relatively low spatial resolution. This physical limitation confines THz wave sensing and imaging to mostly macro-size samples. To investigate local material properties or micro-size structures and devices, near-field technology has to be employed. In this dissertation, the Electro-Optical THz wave emission microscope is investigated. The basic principle is to focus the femtosecond laser to a tight spot on a thin THz emitter layer to produce a THz wave source with a similar size as the focus spot. The apparatus provides a method for placing a THz source with sub-wavelength dimension in the near-field range of the investigated sample. Spatial resolution to the order of one tenth of the THz wavelength is demonstrated by this method. The properties of some widely used THz wave emission materials under tight focused pump light are studied. As an important branch of THz time domain spectroscopy (THz-TDS), THz wave emission spectroscopy has been widely used as a tool to investigate the material physics, such as energy band structure, carrier dynamics, material nonlinear properties and dynamics. As the main work of this dissertation, we propose to combine the THz wave emission spectroscopy with scanning probe microscopy (SPM) to build a tip-assisted THz wave emission microscope (TATEM), which is a valuable extension to current SPM science and technology. Illuminated by a femtosecond laser, the biased SPM tip forms a THz wave source inside the sample beneath the tip. The source size is proportional to the apex size of the tip so

  12. Imaging arrangement and microscope

    Science.gov (United States)

    Pertsinidis, Alexandros; Chu, Steven

    2015-12-15

    An embodiment of the present invention is an imaging arrangement that includes imaging optics, a fiducial light source, and a control system. In operation, the imaging optics separate light into first and second tight by wavelength and project the first and second light onto first and second areas within first and second detector regions, respectively. The imaging optics separate fiducial light from the fiducial light source into first and second fiducial light and project the first and second fiducial light onto third and fourth areas within the first and second detector regions, respectively. The control system adjusts alignment of the imaging optics so that the first and second fiducial light projected onto the first and second detector regions maintain relatively constant positions within the first and second detector regions, respectively. Another embodiment of the present invention is a microscope that includes the imaging arrangement.

  13. Mars Under the Microscope

    Science.gov (United States)

    2004-01-01

    This magnified look at the martian soil near the Mars Exploration Rover Opportunity's landing site, Meridiani Planum, shows coarse grains sprinkled over a fine layer of sand. The image was captured by the rover's microscopic imager on the 10th day, or sol, of its mission. Scientists are intrigued by the spherical rocks, which can be formed by a variety of geologic processes, including cooling of molten lava droplets and accretion of concentric layers of material around a particle or 'seed.'The examined patch of soil is 3 centimeters (1.2 inches) across. The circular grain in the lower left corner is approximately 3 millimeters (.12 inches) across, or about the size of a sunflower seed.

  14. Microscopic Theory of Transconductivity

    Directory of Open Access Journals (Sweden)

    A. P. Jauho

    1998-01-01

    Full Text Available Measurements of momentum transfer between two closely spaced mesoscopic electronic systems, which couple via Coulomb interaction but where tunneling is inhibited, have proven to be a fruitful method of extracting information about interactions in mesoscopic systems. We report a fully microscopic theory for transconductivity σ12, or, equivalently, momentum transfer rate between the system constituents. Our main formal result expresses the transconductivity in terms of two fluctuation diagrams, which are topologically related, but not equivalent to, the Azlamazov-Larkin and Maki-Thompson diagrams known for superconductivity. In the present paper the magnetic field dependence of σ12 is discussed, and we find that σ12(B is strongly enhanced over its zero field value, and it displays strong features, which can be understood in terms of a competition between density-of-states and screening effects.

  15. Analytical Model of the Nonlinear Dynamics of Cantilever Tip-Sample Surface Interactions for Various Acoustic-Atomic Force Microscopies

    Science.gov (United States)

    Cantrell, John H., Jr.; Cantrell, Sean A.

    2008-01-01

    A comprehensive analytical model of the interaction of the cantilever tip of the atomic force microscope (AFM) with the sample surface is developed that accounts for the nonlinearity of the tip-surface interaction force. The interaction is modeled as a nonlinear spring coupled at opposite ends to linear springs representing cantilever and sample surface oscillators. The model leads to a pair of coupled nonlinear differential equations that are solved analytically using a standard iteration procedure. Solutions are obtained for the phase and amplitude signals generated by various acoustic-atomic force microscope (A-AFM) techniques including force modulation microscopy, atomic force acoustic microscopy, ultrasonic force microscopy, heterodyne force microscopy, resonant difference-frequency atomic force ultrasonic microscopy (RDF-AFUM), and the commonly used intermittent contact mode (TappingMode) generally available on AFMs. The solutions are used to obtain a quantitative measure of image contrast resulting from variations in the Young modulus of the sample for the amplitude and phase images generated by the A-AFM techniques. Application of the model to RDF-AFUM and intermittent soft contact phase images of LaRC-cp2 polyimide polymer is discussed. The model predicts variations in the Young modulus of the material of 24 percent from the RDF-AFUM image and 18 percent from the intermittent soft contact image. Both predictions are in good agreement with the literature value of 21 percent obtained from independent, macroscopic measurements of sheet polymer material.

  16. Super-spinning compact objects and models of high-frequency quasi-periodic oscillations observed in Galactic microquasars. II. Forced resonances

    Science.gov (United States)

    Kotrlová, A.; Šrámková, E.; Török, G.; Stuchlík, Z.; Goluchová, K.

    2017-11-01

    In our previous work (Paper I) we applied several models of high-frequency quasi-periodic oscillations (HF QPOs) to estimate the spin of the central compact object in three Galactic microquasars assuming the possibility that the central compact body is a super-spinning object (or a naked singularity) with external spacetime described by Kerr geometry with a dimensionless spin parameter a ≡ cJ/GM2 > 1. Here we extend our consideration, and in a consistent way investigate implications of a set of ten resonance models so far discussed only in the context of a five of these models that involve Keplerian and radial epicyclic oscillations we find the existence of a unique specific QPO excitation radius. Consequently, there is a simple behaviour of dimensionless frequency M × νU(a) represented by a single continuous function having solely one maximum close to a ≳ 1. Only one of these models is compatible with the expectation of a ≳ 1. The other five models that involve the radial and vertical epicyclic oscillations imply the existence of multiple resonant radii. This signifies a more complicated behaviour of M × νU(a) that cannot be represented by single functions. Each of these five models is compatible with the expectation of a ≳ 1.

  17. Atomic force microscopic comparison of remineralization with casein-phosphopeptide amorphous calcium phosphate paste, acidulated phosphate fluoride gel and iron supplement in primary and permanent teeth: An in-vitro study

    Directory of Open Access Journals (Sweden)

    Nikita Agrawal

    2014-01-01

    Full Text Available Context: Demineralization of tooth by erosion is caused by frequent contact between the tooth surface and acids present in soft drinks. Aim: The present study objective was to evaluate the remineralization potential of casein-phosphopeptide-amorphous calcium phosphate (CPP-ACP paste, 1.23% acidulated phosphate fluoride (APF gel and iron supplement on dental erosion by soft drinks in human primary and permanent enamel using atomic force microscopy (AFM. Materials and Methods: Specimens were made from extracted 15 primary and 15 permanent teeth which were randomly divided into three treatment groups: CPP-ACP paste, APF gel and iron supplement. AFM was used for baseline readings followed by demineralization and remineralization cycle. Results and Statistics: Almost all group of samples showed remineralization that is a reduction in surface roughness which was higher with CPP-ACP paste. Statistical analysis was performed using by one-way ANOVA and Mann-Whitney U-test with P < 0.05. Conclusions: It can be concluded that the application of CPP-ACP paste is effective on preventing dental erosion from soft drinks.

  18. Tunable multiwalled nanotube resonator

    Science.gov (United States)

    Jensen, Kenneth J; Girit, Caglar O; Mickelson, William E; Zettl, Alexander K; Grossman, Jeffrey C

    2013-11-05

    A tunable nanoscale resonator has potential applications in precise mass, force, position, and frequency measurement. One embodiment of this device consists of a specially prepared multiwalled carbon nanotube (MWNT) suspended between a metal electrode and a mobile, piezoelectrically controlled contact. By harnessing a unique telescoping ability of MWNTs, one may controllably slide an inner nanotube core from its outer nanotube casing, effectively changing its length and thereby changing the tuning of its resonance frequency. Resonant energy transfer may be used with a nanoresonator to detect molecules at a specific target oscillation frequency, without the use of a chemical label, to provide label-free chemical species detection.

  19. Fundamentals of nanomechanical resonators

    CERN Document Server

    Schmid, Silvan; Roukes, Michael Lee

    2016-01-01

    This authoritative book introduces and summarizes the latest models and skills required to design and optimize nanomechanical resonators, taking a top-down approach that uses macroscopic formulas to model the devices. The authors cover the electrical and mechanical aspects of nano electromechanical system (NEMS) devices. The introduced mechanical models are also key to the understanding and optimization of nanomechanical resonators used e.g. in optomechanics. Five comprehensive chapters address: The eigenmodes derived for the most common continuum mechanical structures used as nanomechanical resonators; The main sources of energy loss in nanomechanical resonators; The responsiveness of micro and nanomechanical resonators to mass, forces, and temperature; The most common underlying physical transduction mechanisms; The measurement basics, including amplitude and frequency noise. The applied approach found in this book is appropriate for engineering students and researchers working with micro and nanomechanical...

  20. Validation of the GROMOS force-field parameter set 45A3 against nuclear magnetic resonance data of hen egg lysozyme

    Energy Technology Data Exchange (ETDEWEB)

    Soares, T. A. [ETH Hoenggerberg Zuerich, Laboratory of Physical Chemistry (Switzerland); Daura, X. [Universitat Autonoma de Barcelona, InstitucioCatalana de Recerca i Estudis Avancats and Institut de Biotecnologia i Biomedicina (Spain); Oostenbrink, C. [ETH Hoenggerberg Zuerich, Laboratory of Physical Chemistry (Switzerland); Smith, L. J. [University of Oxford, Oxford Centre for Molecular Sciences, Central Chemistry Laboratory (United Kingdom); Gunsteren, W. F. van [ETH Hoenggerberg Zuerich, Laboratory of Physical Chemistry (Switzerland)], E-mail: wfvgn@igc.phys.chem.ethz.ch

    2004-12-15

    The quality of molecular dynamics (MD) simulations of proteins depends critically on the biomolecular force field that is used. Such force fields are defined by force-field parameter sets, which are generally determined and improved through calibration of properties of small molecules against experimental or theoretical data. By application to large molecules such as proteins, a new force-field parameter set can be validated. We report two 3.5 ns molecular dynamics simulations of hen egg white lysozyme in water applying the widely used GROMOS force-field parameter set 43A1 and a new set 45A3. The two MD ensembles are evaluated against NMR spectroscopic data NOE atom-atom distance bounds, {sup 3}J{sub NH{alpha}} and {sup 3}J{sub {alpha}}{sub {beta}} coupling constants, and {sup 1}5N relaxation data. It is shown that the two sets reproduce structural properties about equally well. The 45A3 ensemble fulfills the atom-atom distance bounds derived from NMR spectroscopy slightly less well than the 43A1 ensemble, with most of the NOE distance violations in both ensembles involving residues located in loops or flexible regions of the protein. Convergence patterns are very similar in both simulations atom-positional root-mean-square differences (RMSD) with respect to the X-ray and NMR model structures and NOE inter-proton distances converge within 1.0-1.5 ns while backbone {sup 3}J{sub HN{alpha}}-coupling constants and {sup 1}H- {sup 1}5N order parameters take slightly longer, 1.0-2.0 ns. As expected, side-chain {sup 3}J{sub {alpha}}{sub {beta}}-coupling constants and {sup 1}H- {sup 1}5N order parameters do not reach full convergence for all residues in the time period simulated. This is particularly noticeable for side chains which display rare structural transitions. When comparing each simulation trajectory with an older and a newer set of experimental NOE data on lysozyme, it is found that the newer, larger, set of experimental data agrees as well with each of the

  1. Improvements in Mechanical Detection of Magnetic Resonance

    National Research Council Canada - National Science Library

    Fainchtein, Raul

    2005-01-01

    This program intended to provide substantial improvements to conditions that affect imaging nanoscale structures with atomic resolution and chemical specificity by magnetic resonance force microscopy...

  2. Transmission electron microscope CCD camera

    Science.gov (United States)

    Downing, Kenneth H.

    1999-01-01

    In order to improve the performance of a CCD camera on a high voltage electron microscope, an electron decelerator is inserted between the microscope column and the CCD. This arrangement optimizes the interaction of the electron beam with the scintillator of the CCD camera while retaining optimization of the microscope optics and of the interaction of the beam with the specimen. Changing the electron beam energy between the specimen and camera allows both to be optimized.

  3. Proper alignment of the microscope.

    Science.gov (United States)

    Rottenfusser, Rudi

    2013-01-01

    The light microscope is merely the first element of an imaging system in a research facility. Such a system may include high-speed and/or high-resolution image acquisition capabilities, confocal technologies, and super-resolution methods of various types. Yet more than ever, the proverb "garbage in-garbage out" remains a fact. Image manipulations may be used to conceal a suboptimal microscope setup, but an artifact-free image can only be obtained when the microscope is optimally aligned, both mechanically and optically. Something else is often overlooked in the quest to get the best image out of the microscope: Proper sample preparation! The microscope optics can only do its job when its design criteria are matched to the specimen or vice versa. The specimen itself, the mounting medium, the cover slip, and the type of immersion medium (if applicable) are all part of the total optical makeup. To get the best results out of a microscope, understanding the functions of all of its variable components is important. Only then one knows how to optimize these components for the intended application. Different approaches might be chosen to discuss all of the microscope's components. We decided to follow the light path which starts with the light source and ends at the camera or the eyepieces. To add more transparency to this sequence, the section up to the microscope stage was called the "Illuminating Section", to be followed by the "Imaging Section" which starts with the microscope objective. After understanding the various components, we can start "working with the microscope." To get the best resolution and contrast from the microscope, the practice of "Koehler Illumination" should be understood and followed by every serious microscopist. Step-by-step instructions as well as illustrations of the beam path in an upright and inverted microscope are included in this chapter. A few practical considerations are listed in Section 3. Copyright © 2013 Elsevier Inc. All rights

  4. A fluorescence scanning electron microscope

    OpenAIRE

    Kanemaru, Takaaki; Hirata, Kazuho; Takasu, Shin-ichi; Isobe, Shin-Ichiro; Mizuki, Keiji; Mataka, Shuntaro; Nakamura, Kei-ichiro

    2010-01-01

    Fluorescence techniques are widely used in biological research to examine molecular localization, while electron microscopy can provide unique ultrastructural information. To date, correlative images from both fluorescence and electron microscopy have been obtained separately using two different instruments, i.e. a fluorescence microscope (FM) and an electron microscope (EM). In the current study, a scanning electron microscope (SEM) (JEOL JXA8600 M) was combined with a fluorescence digital c...

  5. Scanning Electron Microscope Analysis System

    Data.gov (United States)

    Federal Laboratory Consortium — This facility provides the capability to examine surfaces microscopically with high resolution (5 nanometers), perform micro chemical analyses of these surfaces, and...

  6. Virtopsy hemorrhage of the posterior cricoarytenoid muscle by blunt force to the neck in postmortem multislice computed tomography and magnetic resonance imaging.

    Science.gov (United States)

    Aghayev, Emin; Jackowski, Christian; Sonnenschein, Martin; Thali, Michael; Yen, Kathrin; Dirnhofer, Richard

    2006-03-01

    In forensic autopsies, one of the most important and common signs of violence to the neck is hemorrhages of the soft tissues. The Institute of Forensic Medicine in Bern evaluates the usefulness of postmortem multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) of forensic cases prior to autopsy. The aim of this study was to prove the sensitivity of postmortem MSCT and MRI in the detection of hemorrhages of the neck muscles. A full body scan prior to and a detailed scan of the explanted larynx after autopsy were performed. MSCT detected multiple fractures of the larynx. Detailed MRI was able to demonstrate the hemorrhage of the left posterior cricoarytenoid muscle. The minor hemorrhage of the right posterior cricoarytenoid muscle could not be detected with certainty. Although more experience is required, we conclude that combined MRI and MSCT examination is a useful tool for documentation and examination of neck muscle hemorrhages in forensic cases.

  7. Sub-nanosecond time-resolved near-field scanning magneto-optical microscope.

    Science.gov (United States)

    Rudge, J; Xu, H; Kolthammer, J; Hong, Y K; Choi, B C

    2015-02-01

    We report on the development of a new magnetic microscope, time-resolved near-field scanning magneto-optical microscope, which combines a near-field scanning optical microscope and magneto-optical contrast. By taking advantage of the high temporal resolution of time-resolved Kerr microscope and the sub-wavelength spatial resolution of a near-field microscope, we achieved a temporal resolution of ∼50 ps and a spatial resolution of microscope, the magnetic field pulse induced gyrotropic vortex dynamics occurring in 1 μm diameter, 20 nm thick CoFeB circular disks has been investigated. The microscope provides sub-wavelength resolution magnetic images of the gyrotropic motion of the vortex core at a resonance frequency of ∼240 MHz.

  8. Versatile variable temperature and magnetic field scanning probe microscope for advanced material research

    Science.gov (United States)

    Jung, Jin-Oh; Choi, Seokhwan; Lee, Yeonghoon; Kim, Jinwoo; Son, Donghyeon; Lee, Jhinhwan

    2017-10-01

    We have built a variable temperature scanning probe microscope (SPM) that covers 4.6 K-180 K and up to 7 T whose SPM head fits in a 52 mm bore magnet. It features a temperature-controlled sample stage thermally well isolated from the SPM body in good thermal contact with the liquid helium bath. It has a 7-sample-holder storage carousel at liquid helium temperature for systematic studies using multiple samples and field emission targets intended for spin-polarized spectroscopic-imaging scanning tunneling microscopy (STM) study on samples with various compositions and doping conditions. The system is equipped with a UHV sample preparation chamber and mounted on a two-stage vibration isolation system made of a heavy concrete block and a granite table on pneumatic vibration isolators. A quartz resonator (qPlus)-based non-contact atomic force microscope (AFM) sensor is used for simultaneous STM/AFM operation for research on samples with highly insulating properties such as strongly underdoped cuprates and strongly correlated electron systems.

  9. Infrared up-conversion microscope

    DEFF Research Database (Denmark)

    2014-01-01

    There is presented an up-conversion infrared microscope (110) arranged for imaging an associated object (130), wherein the up-conversion infrared microscope (110) comprises a non-linear crystal (120) arranged for up-conversion of infrared electromagnetic radiation, and wherein an objective optical...

  10. Fano resonances in planar silver nanosphere clusters

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Kui; Nordlander, Peter [Rice Quantum Institute, Laboratory for Nanophotonics, Houston (United States); Rice University, Department of Physics, Houston, TX (United States); Mirin, Nikolay A. [Rice Quantum Institute, Laboratory for Nanophotonics, Houston (United States); Rice University, Department of Chemistry, Houston, TX (United States)

    2010-08-15

    The plasmonic properties of silver nanosphere clusters are investigated using the finite element and the plasmon hybridization methods. The nanoparticle clusters are found to exhibit multiple plasmon resonances with large induced electromagnetic field enhancements. For symmetric clusters, we show how group theory can be used to identify the microscopic nature of the plasmon resonances. For larger clusters, we show that narrow Fano resonances are frequently present in their optical spectra. (orig.)

  11. Microscopic picture of the aqueous solvation of glutamic acid

    NARCIS (Netherlands)

    Leenders, E.J.M.; Bolhuis, P.G.; Meijer, E.J.

    2008-01-01

    We present molecular dynamics simulations of glutamic acid and glutamate solvated in water, using both density functional theory (DFT) and the Gromos96 force field. We focus on the microscopic aspects of the solvation−particularly on the hydrogen bond structures and dynamics−and investigate the

  12. Modification Of Normal Microscope To Magneto-Optical Microscope

    Directory of Open Access Journals (Sweden)

    Nurazlin Ahmad

    2015-04-01

    Full Text Available Abstract The present work reports on the modification of polarizing microscope to a magnetic domain imaging microscope based on Faraday Effect. Sample used in this research is a ferromagnetic garnet BiTmNa3FeGa5O12. The halogen lamp in the microscope is replaced by helium-neon HeNe laser as a light source. To reduce the laser spatial coherent effect thin transparent plastics placed in the laser path. The plastics are rotated at certain velocity. Other factors to be considered are the plastic rotation velocity the laser intensity and the laser alignment. Typical magnetic domain pattern is obtained with the new system.

  13. The head-mounted microscope.

    Science.gov (United States)

    Chen, Ting; Dailey, Seth H; Naze, Sawyer A; Jiang, Jack J

    2012-04-01

    Microsurgical equipment has greatly advanced since the inception of the microscope into the operating room. These advancements have allowed for superior surgical precision and better post-operative results. This study focuses on the use of the Leica HM500 head-mounted microscope for the operating phonosurgeon. The head-mounted microscope has an optical zoom from 2× to 9× and provides a working distance from 300 mm to 700 mm. The headpiece, with its articulated eyepieces, adjusts easily to head shape and circumference, and offers a focus function, which is either automatic or manually controlled. We performed five microlaryngoscopic operations utilizing the head-mounted microscope with successful results. By creating a more ergonomically favorable operating posture, a surgeon may be able to obtain greater precision and success in phonomicrosurgery. Phonomicrosurgery requires the precise manipulation of long-handled cantilevered instruments through the narrow bore of a laryngoscope. The head-mounted microscope shortens the working distance compared with a stand microscope, thereby increasing arm stability, which may improve surgical precision. Also, the head-mounted design permits flexibility in head position, enabling operator comfort, and delaying musculoskeletal fatigue. A head-mounted microscope decreases the working distance and provides better ergonomics in laryngoscopic microsurgery. These advances provide the potential to promote precision in phonomicrosurgery. Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.

  14. Resonances in QCD

    Energy Technology Data Exchange (ETDEWEB)

    Lutz, Matthias F. M.; Lange, Jens Sören; Pennington, Michael; Bettoni, Diego; Brambilla, Nora; Crede, Volker; Eidelman, Simon; Gillitzer, Albrecht; Gradl, Wolfgang; Lang, Christian B.; Metag, Volker; Nakano, Takashi; Nieves, Juan; Neubert, Sebastian; Oka, Makoto; Olsen, Stephen L.; Pappagallo, Marco; Paul, Stephan; Pelizäus, Marc; Pilloni, Alessandro; Prencipe, Elisabetta; Ritman, Jim; Ryan, Sinead; Thoma, Ulrike; Uwer, Ulrich; Weise, Wolfram

    2016-04-01

    We report on the EMMI Rapid Reaction Task Force meeting 'Resonances in QCD', which took place at GSI October 12-14, 2015 (Fig.~1). A group of 26 people met to discuss the physics of resonances in QCD. The aim of the meeting was defined by the following three key questions; what is needed to understand the physics of resonances in QCD?; where does QCD lead us to expect resonances with exotic quantum numbers?; and what experimental efforts are required to arrive at a coherent picture? For light mesons and baryons only those with up, down and strange quark content were considered. For heavy-light and heavy-heavy meson systems, those with charm quarks were the focus.This document summarizes the discussions by the participants, which in turn led to the coherent conclusions we present here.

  15. Fluid flows and forces in development: functions, features and biophysical principles

    OpenAIRE

    Freund, Jonathan B.; Jacky G Goetz; Kent L Hill; Vermot, Julien

    2012-01-01

    Throughout morphogenesis, cells experience intracellular tensile and contractile forces on microscopic scales. Cells also experience extracellular forces, such as static forces mediated by the extracellular matrix and forces resulting from microscopic fluid flow. Although the biological ramifications of static forces have received much attention, little is known about the roles of fluid flows and forces during embryogenesis. Here, we focus on the microfluidic forces generated by cilia-driven ...

  16. Nonlinear Dynamics of Cantilever-Sample Interactions in Atomic Force Microscopy

    Science.gov (United States)

    Cantrell, John H.; Cantrell, Sean A.

    2010-01-01

    The interaction of the cantilever tip of an atomic force microscope (AFM) with the sample surface is obtained by treating the cantilever and sample as independent systems coupled by a nonlinear force acting between the cantilever tip and a volume element of the sample surface. The volume element is subjected to a restoring force from the remainder of the sample that provides dynamical equilibrium for the combined systems. The model accounts for the positions on the cantilever of the cantilever tip, laser probe, and excitation force (if any) via a basis set of set of orthogonal functions that may be generalized to account for arbitrary cantilever shapes. The basis set is extended to include nonlinear cantilever modes. The model leads to a pair of coupled nonlinear differential equations that are solved analytically using a matrix iteration procedure. The effects of oscillatory excitation forces applied either to the cantilever or to the sample surface (or to both) are obtained from the solution set and applied to the to the assessment of phase and amplitude signals generated by various acoustic-atomic force microscope (A-AFM) modalities. The influence of bistable cantilever modes of on AFM signal generation is discussed. The effects on the cantilever-sample surface dynamics of subsurface features embedded in the sample that are perturbed by surface-generated oscillatory excitation forces and carried to the cantilever via wave propagation are accounted by the Bolef-Miller propagating wave model. Expressions pertaining to signal generation and image contrast in A-AFM are obtained and applied to amplitude modulation (intermittent contact) atomic force microscopy and resonant difference-frequency atomic force ultrasonic microscopy (RDF-AFUM). The influence of phase accumulation in A-AFM on image contrast is discussed, as is the effect of hard contact and maximum nonlinearity regimes of A-AFM operation.

  17. A Miniaturized In Situ Tensile Platform under Microscope

    Directory of Open Access Journals (Sweden)

    Xiaoli Hu

    2012-09-01

    Full Text Available Aiming at the mechanical testing of three-dimensional specimens with feature size of centimeter level, a miniaturized tensile platform, which presents compatibility with scanning electron microscope (SEM and metallographic microscope, was designed and built. The platform could accurately evaluate the parameters such as elastic modulus, elongation and yield limit, etc. The calibration experiments of load sensor and displacement sensor showed the two kinds of sensors had high linearity. Testing of transmission error and modal parameters showed that the platform presented good following behaviors and separation of resonance region. Comparison tests based on stress-strain curve were carried out between the self-made platform and the commercial tensile instrument (Instron to verify the feasibility of the platform. Furthermore, the in situ tensile experiment under metallographic microscope was carried out on a kind of manganese steel.

  18. Near-field optical microscope using a silicon-nitride probe

    NARCIS (Netherlands)

    van Hulst, N.F.; Moers, M.H.P.; Moers, M.H.P.; Noordman, O.F.J.; Noordman, O.F.J.; Tack, R.G.; Segerink, Franciscus B.; Bölger, B.; Bölger, B.

    1993-01-01

    Operation of an alternative near-field optical microscope is presented. The microscope uses a microfabricated silicon- nitride probe with integrated cantilever, as originally developed for force microscopy. The cantilever allows routine close contact near-field imaging o­n arbitrary surfaces without

  19. Scanning tunneling microscope spectroscopy of polymers.

    Science.gov (United States)

    Zypman, Fredy R

    2002-01-01

    This paper presents theoretical results on the relationship between density of states (DOS) and scanning tunneling microscope current-voltage curves in polymers. We considered samples of linear hydrocarbons electrically grounded at one of their extremes. The other extreme is electrically connected to the microscope tip via electron tunneling through vacuum. When a voltage, V, is applied to the tip, electric current, I, flows in the tip-sample circuit. This current varies as the voltage varies and depends on the DOS to the extent that no current would flow if no electron states exist at a certain energy (or voltage). The detailed relationship between DOS and the current-voltage (I-V) curve is not known a priori. We solve the corresponding quantum problem in the context of tight binding and find that I-V reproduces accurately the resonant energy peaks of the DOS. We apply the results to 100 atom-long alkane and alkene chains and found that there is a significant voltage shift in the corresponding curves as to discriminate one structure from the other.

  20. Progress towards a Fermi Gas Microscope

    Science.gov (United States)

    Gersdorf, Thomas; Ramasesh, Vinay; Inoue, Takuma; Okan, Melih; Reens, David; Goldstein, Jordan; Bakr, Waseem; Zwierlein, Martin

    2012-06-01

    Attractively interacting degenerate Fermi gases near a Feshbach resonance have been used to realize the BEC-BCS crossover, while repulsive gases in optical lattices are expected to shed light on the physics of high-temperature superconductors. Local probes of these atomic systems should reveal microscopic correlations in such strongly interacting systems that cannot be directly extracted from bulk measurements. With the advent of quantum gas microscopy, the potential of such local probes has been demonstrated in bosonic gases. We are developing an experimental apparatus that combines quantum gas microscopy techniques with ultracold fermions in optical lattices to simulate strongly-correlated electronic systems. Our apparatus is designed to create degenerate gases of fermionic lithium and potassium as well as bosonic sodium. The gases will be loaded into a single layer of an optical lattice and imaged with a sub-micron resolution optical system capable of resolving individual sites. Our system opens the door to microscopic studies of phases that appear in the Fermi-Hubbard model including fermionic Mott insulators, antiferromagnets and d-wave superfluids, as well as topological phases that arise in the presence of synthetic gauge fields.

  1. Quantum Non-Demolition Measurements between a Graphene Nanomechanical Resonator and a Diamond Nitrogen-Vacancy Center

    Science.gov (United States)

    D'Urso, Brian

    2013-03-01

    A description of the motion of microscopic particles often requires quantum mechanics, but macroscopic objects are typically observed to follow the predictions of classical mechanics. In the transition from microscopic components to a complex macroscopic system, the distinctive features of quantum mechanics can be hidden by thermal excitations and coupling to the environment. In particular, while individual spins are intrinsically quantum objects, nanomechanical resonators are usually observed as classical damped oscillators. With a careful choice of coupling, these two systems can be made to interact such that they perform quantum non-demolition (QND) measurements on each other, enabling a bridge between the quantum and classical worlds. Through this coupling, the nanomechanical resonator provides a classical readout of the spin, while the spin acts as a probe of the discrete quantum states of the resonator. We present a system consisting of a graphene nanoelectromechanical resonator coupled to a single spin through a uniform external magnetic field. The spin originates from a nitrogen-vacancy (NV) center in a diamond nanocrystal, which is positioned on the resonator. The external magnetic field provides quadratic coupling which results in QND measurements between the spin and resonator. The strength of the quadratic coupling is enhanced by utilizing an avoided level crossing of the coupled spin-resonator system. The low mass of a graphene resonator further increases the sensitivity to the force associated with a single spin. NV centers are chosen as the source of a spin due to their exceptional spin state coherence times, large zero-field splitting, and optical addressability. We will present an analysis of the system and report on the status of experimental measurements with graphene-NV center devices. This work is funded by a DARPA Young Faculty Award.

  2. Overview of the Microscope Objective

    Science.gov (United States)

    Niu, Ruijuan

    Microscopes are widely used in research and industry. The objective lens is the most significant part of the microscope. Some characteristics and different types of microscope objectives are discussed in this thesis. The markings on the objective indicate some main optical characteristics. However, it is not always possible to know the materials, the radius or the thickness of each surface in an objective lens and it is not easy to simulate an objective without this data. In this thesis, we build a first order model which can simulate a refractive microscope objective when the magnification and numerical aperture are known. The model contains a thin lens made by two standard surfaces and also simulates the principal planes. This model provides more accurate ray heights and it is aplanatic. Some design examples of an objective lens are also discussed in order to get a better understanding of design and optimization considerations.

  3. Microscopic examination of deteriorated concrete

    NARCIS (Netherlands)

    Nijland, T.G.; Larbi, J.A.

    2010-01-01

    Concrete petrography is the integrated microscopic and mesoscale (hand specimen size) investigation of hardened concrete, that can provide information on the composition of concrete, the original relationships between the concrete's various constituents, and any changes therein, whether as a result

  4. (Center of excellence: Microlaser microscope)

    Energy Technology Data Exchange (ETDEWEB)

    Webb, R.H.

    1992-01-01

    This Center-of-Excellence grant has two components: development of an imaging system based on microlaser arrays forms a central project among a group of laser diagnostic and therapeutic efforts primarily funded outside the grant. In these first 8 months we have set up the Microlaser Microscope using small microlaser arrays. We have emphasized the basics of microlaser handling and electronic addressing and the optics of the microscope. Details of electronics and optics given here will be used in the larger arrays which should be available soon. After a description of the central Microlaser Microscope project, we touch briefly on the other projects of the Center, which have been outstandingly fruitful this year. Publications are necessarily concerned with the smaller projects, since the Microlaser Microscope is in its early stages.

  5. Microscopic Procedures for Plant Meiosis.

    Science.gov (United States)

    Braselton, James P.

    1997-01-01

    Describes laboratory techniques designed to familiarize students with meiosis and how microscopic preparations of meiosis are made. These techniques require the use of fresh or fixed flowers. Contains 18 references. (DDR)

  6. Scanning laser video camera/ microscope

    Science.gov (United States)

    Wang, C. P.; Bow, R. T.

    1984-10-01

    A laser scanning system capable of scanning at standard video rate has been developed. The scanning mirrors, circuit design and system performance, as well as its applications to video cameras and ultra-violet microscopes, are discussed.

  7. [MICROSCOPIC COLITIS: THE CLINICAL CASE].

    Science.gov (United States)

    Kulygina, Y A; Skalinskaya, M I; Ageeva, T A

    2015-01-01

    During past years incidence and prevalence of microscopic colitis (MC) have increased, that is possible caused to the improvement of knowledge of doctors about the disease. This article contain modern views on epidemiology, diagnostic and variant of microscopic colitis treatment. A typical clinical picture of MC in the form of recurrent a watery diarrhea, with the absence of pathologic changes at roentgenologic and endoscopic investigations is described with the example of a clinical case.

  8. In situ atomic force microscope imaging of supported lipid bilayers

    DEFF Research Database (Denmark)

    Kaasgaard, Thomas; Leidy, Chad; Ipsen, John Hjorth

    2001-01-01

    In situ AFM images of phospholipase A/sub 2/ (PLA/sub 2/) hydrolysis of mica-supported one- and two-component lipid bilayers are presented. For one-component DPPC bilayers an enhanced enzymatic activity is observed towards preexisting defects in the bilayer. Phase separation is observed in two-co...

  9. Measuring microscopic forces and torques using optical tweezers

    CSIR Research Space (South Africa)

    McLaren, MG

    2009-07-01

    Full Text Available of fluid Velocity of fluid Radius of particle Thank You Join the Mathematical Optics research team! Opportunities: MSc and PhD studentships, Post docs and Sabbaticals Contact: Dr Andrew Forbes or Dr Stef Roux www.csir.co.za/lasers/index_mathematical_optics.html ...

  10. A low temperature scanning force microscope for biological samples

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, Mats Gustaf Lennart [Univ. of California, Berkeley, CA (United States)

    1993-05-01

    An SFM has been constructed capable of operating at 143 K. Two contributions to SFM technology are described: a new method of fabricating tips, and new designs of SFM springs that significantly lower the noise level. The SFM has been used to image several biological samples (including collagen, ferritin, RNA, purple membrane) at 143 K and room temperature. No improvement in resolution resulted from 143 K operation; several possible reasons for this are discussed. Possibly sharper tips may help. The 143 K SFM will allow the study of new categories of samples, such as those prepared by freeze-frame, single molecules (temperature dependence of mechanical properties), etc. The SFM was used to cut single collagen molecules into segments with a precision of {le} 10 nm.

  11. The Atomic Force Microscopic (AFM) Characterization of Nanomaterials

    Science.gov (United States)

    2009-06-01

    and then dried in air on aluminum foil before transfer into DMF for sonication. Figure 15 shows the AFM results after the XDCNTs/WC were tip...was tested to have a tensile strength of 63 gigapascals (GPa), which translates into the CNT’s ability to endure the weight of 6300 kg on a cable with...separate layers by their buoyancy differences. The author suggested that this might be caused by the surfactants’ organization around SWNTs comprising

  12. Atomic Force Microscope 2: Digital Instruments/Veeco Dimension 3000

    Data.gov (United States)

    Federal Laboratory Consortium — Description:CORAL Name: AFM 2A tool used to study the material surface characteristics, check the surface patterns generated by nanofabrication. It can take samples...

  13. Accurate measurement of microscopic forces and torques using optical tweezers

    CSIR Research Space (South Africa)

    McLaren, M

    2011-09-01

    Full Text Available , Dholakia K, Allen L, Padgett MJ. Mechanical equivalence of spin and orbital angular momentum of light: An optical spanner. Opt Lett. 1997;22:52?54. doi:10.1364/OL.22.000052, PMid:18183100 17. Allen L, Beijersbergen MW, Spreeuw RJC, Woerdman JP. Orbital...

  14. Model Development for Atomic Force Microscope Stage Mechanisms

    National Research Council Canada - National Science Library

    Smith, Ralph C; Hatch, Andrew G; De, Tathagata; Salapaka, Murti V; Raye, Julie K; del Rosario, Ricardo C

    2005-01-01

    In this paper, we develop nonlinear constitutive equations and resulting system models quantifying the nonlinear and hysteretic field-displacement relations inherent to lead zirconate titanate (PZT...

  15. Atomic Force Microscopy

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 7. Atomic Force Microscopy - A Tool to Unveil the Mystery of Biological Systems ... Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 ...

  16. An Inexpensive Interferometric Setup for Measuring Microscopic Displacements

    Science.gov (United States)

    Alanís, Elvio; Romero, Graciela; Martínez, Carlos; Álvarez, Liliana; Salazar, Germán

    2004-04-01

    In an interesting article published in an issue of The Physics Teacher, Reichert gives some didactic examples about static friction force between a plastic block and a wooden plane on which it rests. To explain the experiments, he uses a simple model based on a microscopic "elastic band" that connects the atoms of both surfaces. Reichert remarks that "the block moves, albeit a microscopic distance," and that it would be helpful if the student could see these displacements. In another paragraph he states that "measuring it (displacement) requires delicate and expensive optical instruments." Effectively, a measurement of such small displacements generally requires interferometric devices. At our university, we teach basic physics and we are aware of the difficulties that beginners have grasping the concepts involved in static friction force. At the same time, as our research field is related to optics metrology, we could not ignore Reichert's statement. Could we design an experimental device to measure the microscopic displacement referred to by Reichert, keeping it inexpensive and easy to implement? Incidentally, in the same issue of The Physics Teacher, Sawicki2 gives an excellent example of how, with a few common elements, a simple experiment of interferometric measurement can be put within students' reach. In this paper, we suggest the use of a simple interferometric device, built with very common and inexpensive elements, and describe an experiment on static friction force in which the instrument is applied to measure microscopic displacements.

  17. Optical Near-field Interactions and Forces for Optoelectronic Devices

    Science.gov (United States)

    Kohoutek, John Michael

    Throughout history, as a particle view of the universe began to take shape, scientists began to realize that these particles were attracted to each other and hence came up with theories, both analytical and empirical in nature, to explain their interaction. The interaction pair potential (empirical) and electromagnetics (analytical) theories, both help to explain not only the interaction between the basic constituents of matter, such as atoms and molecules, but also between macroscopic objects, such as two surfaces in close proximity. The electrostatic force, optical force, and Casimir force can be categorized as such forces. A surface plasmon (SP) is a collective motion of electrons generated by light at the interface between two mediums of opposite signs of dielectric susceptibility (e.g. metal and dielectric). Recently, surface plasmon resonance (SPR) has been exploited in many areas through the use of tiny antennas that work on similar principles as radio frequency (RF) antennas in optoelectronic devices. These antennas can produce a very high gradient in the electric field thereby leading to an optical force, similar in concept to the surface forces discussed above. The Atomic Force Microscope (AFM) was introduced in the 1980s at IBM. Here we report on its uses in measuring these aforementioned forces and fields, as well as actively modulating and manipulating multiple optoelectronic devices. We have shown that it is possible to change the far field radiation pattern of an optical antenna-integrated device through modification of the near-field of the device. This modification is possible through change of the local refractive index or reflectivity of the "hot spot" of the device, either mechanically or optically. Finally, we have shown how a mechanically active device can be used to detect light with high gain and low noise at room temperature. It is the aim of several of these integrated and future devices to be used for applications in molecular sensing

  18. The Microscope Mission and Its Uncertainty Analysis

    Science.gov (United States)

    Touboul, Pierre

    2009-12-01

    The accurate test of the Universality of Free Fall may demonstrate a violation of Einstein Equivalence Principle (EP) as most attempts of Grand Unification theories seem to conduct. The MICROSCOPE space mission aims at an accuracy of 10-15 with a small drag free satellite and a payload based on electrostatic inertial sensors. The two test-masses made of Platinum and Titanium alloys are forced to follow accurately the same orbit. The sets of surrounding electrodes carried by gold coated silica parts allows the generation of electrical fields and electrostatic pressures on the masses. Common forces and torques are exploited to control the satellite drag compensation system and its fine inertial or rotating pointing. Difference in the force along the Earth gravity monopole is accurately measured and interpreted for the test. After a short presentation of the mission and the instrument, most of the relevant parameters to the experiment performance are detailed as well as the associated technologies to reach the expected levels of accuracy. Present error budgets confirm the test expected accuracy of better than 10-15.

  19. 849 RESONANCE | September 2013

    Indian Academy of Sciences (India)

    IAS Admin

    849. RESONANCE | September 2013. Page 2. 850. RESONANCE | September 2013. Page 3. 851. RESONANCE | September 2013. Page 4. 852. RESONANCE | September 2013. Page 5. 853. RESONANCE | September 2013. Page 6. 854. RESONANCE | September 2013. Page 7. 855. RESONANCE | September 2013.

  20. Stepwise unfolding of titin under force-clamp atomic force microscopy

    OpenAIRE

    Andres F. Oberhauser; Hansma, Paul K.; Carrion-Vazquez, Mariano; Fernandez, Julio M.

    2001-01-01

    Here we demonstrate the implementation of a single-molecule force clamp adapted for use with an atomic force microscope. We show that under force-clamp conditions, an engineered titin protein elongates in steps because of the unfolding of its modules and that the waiting times to unfold are exponentially distributed. Force-clamp measurements directly measure the force dependence of the unfolding probability and readily captures the different mechanical stability of the...

  1. Adhesion force imaging in air and liquid by adhesion mode atomic force microscopy

    NARCIS (Netherlands)

    van der Werf, Kees; Putman, C.A.J.; Putman, Constant A.; de Grooth, B.G.; Greve, Jan

    1994-01-01

    A new imaging mode for the atomic force microscope(AFM), yielding images mapping the adhesion force between tip and sample, is introduced. The adhesion mode AFM takes a force curve at each pixel by ramping a piezoactuator, moving the silicon‐nitride tip up and down towards the sample. During the

  2. Microscopic description of nuclear shapes

    Energy Technology Data Exchange (ETDEWEB)

    Egido, J.L.; Robledo, L.M.; Valor, A.; Villafranca, A. [Universidad Autonoma de Madrid (Spain)

    1996-12-31

    The approximate particle number theory for density dependent forces is sketched, the theory is applied to discuss properties of the superdeformed ground state and excited bands of {sup 192}Hg. The force used in the calculations is the finite range density dependent Gogny force. The agreement with the available experimental results is very satisfactory.

  3. Comparing the photocatalytic activity of TiO2at macro- and microscopic scales.

    Science.gov (United States)

    Torras-Rosell, Antoni; Johannsen, Sabrina Rostgaard; Dirscherl, Kai; Daviðsdóttir, Svava; Jeppesen, Christian Sloth; Louring, Sascha; Andersen, Inge Hald

    2017-05-01

    This study focuses on the characterization of photocatalytic TiO 2 coatings using Kelvin probe force microscopy. While most photocatalytic experiments are carried out at a macroscopic scale, Kelvin probe force microscopy is a microscopic technique that is surface sensitive. In order to link microscale results to macroscopic experiments, a simple method to establish the relation between Kelvin probe force microscopy and electrochemical measurements is presented by the calibration of a reference sample consisting of epitaxial deposited Cu-Ni-Au that is used as a transfer standard. The photocatalytic properties of TiO 2 at macro- and microscopic scales are investigated by comparing photocatalytic degradation of acetone and electrochemical experiments to Kelvin probe force microscopy. The good agreement between the macro- and microscopic experiments suggests that Kelvin probe force microscopy can be a valuable tool towards the understanding, standardization and design of TiO 2 -based solutions in photocatalytic applications.

  4. The A sub y problem in refined resonating group model calculations for p- sup 3 He scattering

    CERN Document Server

    Reiss, C

    2003-01-01

    We report on a microscopic Refined Resonating Group Model (RRGM) calculation of scattering of p off sup 3 He employing the Argonne-v sub 1 sub 4 and the Bonn nucleon-nucleon potentials without three-nucleon forces at low energies up to 30 MeV. The calculated phase shifts verify the well-known proton analyzing power A sub y problem. We demonstrate that with corrected sup 3 P sub 2 phase shifts experimental differential cross-section and analyzing power data can be explained.

  5. Microscope and method of use

    Science.gov (United States)

    Bongianni, Wayne L.

    1984-01-01

    A method and apparatus for electronically focusing and electronically scanning microscopic specimens are given. In the invention, visual images of even moving, living, opaque specimens can be acoustically obtained and viewed with virtually no time needed for processing (i.e., real time processing is used). And planar samples are not required. The specimens (if planar) need not be moved during scanning, although it will be desirable and possible to move or rotate nonplanar specimens (e.g., laser fusion targets) against the lens of the apparatus. No coupling fluid is needed, so specimens need not be wetted. A phase acoustic microscope is also made from the basic microscope components together with electronic mixers.

  6. Microscopic colitis: a concise review.

    Science.gov (United States)

    Zippi, M; Marcheggiano, A; Crispino, P; Occhigrossi, G; Severi, C

    2010-01-01

    Microscopic colitis is an increasingly common cause of chronic watery diarrhoea, and often a causes of abdominal pain of unknown origins. The increase of interest for this clinical entity is due to a misdiagnosis of any symptoms that have been frequently attributed to diarrhea-predominant irritable bowel syndrome, often for many years before diagnosis. Presumably, most estimates of incidence and prevalence understate the true frequency of microscopic colitis for this reason. The aim of this paper is to evaluate the importance of microscopic colitis as cause of chronic non bloody diarrhoea, on the basis of literature review. These kind of colitis are characterized by normal colonic mucosa at endoscopy or barium enema but with increased inflammation in colonic biopsies. Microscopic colitis consists of two main subtypes, collagenous colitis and lymphocytic colitis, distinguished by the presence of absence of a thickened subepithelial collagen band. Several models of pathogenesis has been proposed but no convincing mechanism has been identified, although is difficult to characterize this clinical entity as an independent phenomenon or a simple manifestation or related factors active to induce microscopic changing in the colonic mucosa. A rational approach to therapy does not exist and was conduct with several types of drugs after the exclusion of other causes, commonly characterized by this symptoms and the definitive histological assessment in the biopsies specimens. In the majority of cases this condition tends to follow a self-limited course but potentially can assume the characteristics of relapsing course with the necessity to a chronic therapy. Several long-term follow-up studies excluded a possible progression to neoplastic malignancies of microscopic colitis.

  7. Atomic force microscopy and direct surface force measurements

    NARCIS (Netherlands)

    Ralston, J.; Larson, I.; Rutland, M.; Feiler, A.; Kleijn, J.M.

    2005-01-01

    The atomic force microscope (AFM) is designed to provide high-resolution (in the ideal case, atomic) topographical analysis, applicable to both conducting and nonconducting surfaces. The basic imaging principle is very simple: a sample attached to a piezoelectric positioner is rastered beneath a

  8. Electrothermally Tunable Bridge Resonator

    KAUST Repository

    Hajjaj, Amal Z.

    2016-12-05

    This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of an in-plane clamped-clamped microbeam, bridge, and resonator compressed by a force due to electrothermal actuation. We demonstrate that a single resonator can be operated at a wide range of frequencies. The microbeam is actuated electrothermally, by passing a DC current through it. We show that when increasing the electrothermal voltage, the compressive stress inside the microbeam increases, which leads eventually to its buckling. Before buckling, the fundamental frequency decreases until it drops to very low values, almost to zero. After buckling, the fundamental frequency increases, which is shown to be as high as twice the original resonance frequency. Analytical results based on the Galerkin discretization of the Euler Bernoulli beam theory are generated and compared to the experimental data and to simulation results of a multi-physics finite-element model. A good agreement is found among all the results.

  9. Dielectrophoretic spectroscopy using a microscopic electrode array

    Science.gov (United States)

    Kirmani, Syed Abdul Mannan; Gudagunti, Fleming Dackson; Velmanickam, Logeeshan; Nawarathna, Dharmakeerthi; Lima, Ivan T.

    2017-02-01

    Dielectrophoresis (DEP) is a commonly used technique in biomedical engineering to manipulate biomolecules. DEP is defined as the force acting on dielectric particles when they are exposed to non-uniform electric fields. DEP effect can be divided in three categories: positive (dielectric particles are attracted to the electrodes), negative, and zero force DEP. The cross-over frequency is the frequency in which the DEP force is equal to zero. The cross-over frequency depends on the conductivity and the permittivity of the particles and of the suspended medium. The DEP cross-over frequency has been utilized in detecting/quantifying biomolecules. A manual procedure is commonly used to estimate the cross-over frequency of biomolecules. Therefore, the accuracy of this detection method is significantly limited. To address this issue, we designed and tested an automated procedure to carry out DEP spectroscopy in dielectric particles dissolved in a biological buffer solution. Our method efficiently measures the effect of the DEP force through a live video feed from the microscope camera and performs real-time image processing. It records the change in the fluorescence emission as the system automatically scans the electric frequency of the function generator over a specified time interval. We demonstrated the effectiveness of the method by extracting the crossover frequencies and the DEP spectrum of polystyrene beads with blue color dye (1000 nm diameter) and green fluorescent polystyrene beads with 500 nm diameter using this procedure. This approach can lead to the development of a biosensor with significantly higher sensitivity than existing detection methods.

  10. Dynamics of an [Fe4S4(SPh)4]2- cluster explored via IR, Raman, and nuclear resonance vibrational spectroscopy (NRVS)-analysis using 36S substitution, DFT calculations, and empirical force fields.

    Science.gov (United States)

    Xiao, Yuming; Koutmos, Markos; Case, David A; Coucouvanis, Dimitri; Wang, Hongxin; Cramer, Stephen P

    2006-05-14

    We have used four vibrational spectroscopies--FT-IR, FT-Raman, resonance Raman, and 57Fe nuclear resonance vibrational spectroscopy (NRVS)--to study the normal modes of the Fe-S cluster in [(n-Bu)4N]2[Fe4S4(SPh)4]. This [Fe4S4(SR)4]2- complex serves as a model for the clusters in 4Fe ferredoxins and high-potential iron proteins (HiPIPs). The IR spectra exhibited differences above and below the 243 K phase transition. Significant shifts with 36S substitution into the bridging S positions were also observed. The NRVS results were in good agreement with the low temperature data from the conventional spectroscopies. The NRVS spectra were interpreted by normal mode analysis using optimized Urey-Bradley force fields (UBFF) as well as from DFT theory. For the UBFF calculations, the parameters were refined by comparing calculated and observed NRVS frequencies and intensities. The frequency shifts after 36S substitution were used as an additional constraint. A D 2d symmetry Fe4S4S'4 model could explain most of the observed frequencies, but a better match to the observed intensities was obtained when the ligand aromatic rings were included for a D 2d Fe4S4(SPh)4 model. The best results were obtained using the low temperature structure without symmetry constraints. In addition to stretching and bending vibrations, low frequency modes between approximately 50 and 100 cm(-1) were observed. These modes, which have not been seen before, are interpreted as twisting motions with opposing sides of the cube rotating in opposite directions. In contrast with a recent paper on a related Fe4S4 cluster, we find no need to assign a large fraction of the low frequency NRVS intensity to 'rotational lattice modes'. We also reassign the 430 cm(-1) band as primarily an elongation of the thiophenolate ring, with approximately 10% terminal Fe-S stretch character. This study illustrates the benefits of combining NRVS with conventional Raman and IR analysis for characterization of Fe-S centers. DFT

  11. Recording force events of single quantum-dot endocytosis.

    Science.gov (United States)

    Shan, Yuping; Hao, Xian; Shang, Xin; Cai, Mingjun; Jiang, Junguang; Tang, Zhiyong; Wang, Hongda

    2011-03-28

    We applied force spectroscopy based on atomic force microscope (AFM) to demonstrate the possibility of measuring the interaction force between single quantum-dots (QDs) and living cells at single particle level under native conditions. In the force-distance cycle, we recorded the events of cellular uptake of single QDs and single QD detachment from the cell.

  12. Vibrational resonance in the Morse oscillator

    Indian Academy of Sciences (India)

    Abstract. The occurrence of vibrational resonance is investigated in both classical and quantum mechanical Morse oscillators driven by a biharmonic force. The biharmonic force consists of two forces of widely different frequencies ω and with. ≫ ω. In the damped and biharmoni- cally driven classical Morse oscillator, ...

  13. Piezoelectric Resonance Investigation of Zr-rich PZT at Room Temperature

    NARCIS (Netherlands)

    Cereceda, N.; Noheda, B.; Fernandez-del-Castillo, J.R.; Gonzalo, J.A.; Frutos, J. De

    1999-01-01

    We study the piezoelectric resonances in poled PZT ceramics by means of a microscopic model. It connects the microscopic vibrations of the ionic units, cooperatively producing the piezoelectric effect, with the macroscopic piezoelectric parameters. The behaviour at the resonance is well described in

  14. Development and design of advanced two-photon microscope used in neuroscience

    Science.gov (United States)

    Doronin, M. S.; Popov, A. V.

    2016-08-01

    This work represents the real steps to development and design advanced two-photon microscope by efforts of laboratory staff. Self-developed microscopy system provides possibility to service it and modify the structure of microscope depending on highly specialized experimental design and scientific goals. We are presenting here module-based microscopy system which provides an opportunity to looking for new applications of this setup depending on laboratories needs using with galvo and resonant scanners.

  15. Efficient primary and parametric resonance excitation of bistable resonators

    KAUST Repository

    Ramini, Abdallah

    2016-09-12

    We experimentally demonstrate an efficient approach to excite primary and parametric (up to the 4th) resonance of Microelectromechanical system MEMS arch resonators with large vibrational amplitudes. A single crystal silicon in-plane arch microbeam is fabricated such that it can be excited axially from one of its ends by a parallel-plate electrode. Its micro/nano scale vibrations are transduced using a high speed camera. Through the parallel-plate electrode, a time varying electrostatic force is applied, which is converted into a time varying axial force that modulates dynamically the stiffness of the arch resonator. Due to the initial curvature of the structure, not only parametric excitation is induced, but also primary resonance. Experimental investigation is conducted comparing the response of the arch near primary resonance using the axial excitation to that of a classical parallel-plate actuation where the arch itself forms an electrode. The results show that the axial excitation can be more efficient and requires less power for primary resonance excitation. Moreover, unlike the classical method where the structure is vulnerable to the dynamic pull-in instability, the axial excitation technique can provide large amplitude motion while protecting the structure from pull-in. In addition to primary resonance, parametrical resonances are demonstrated at twice, one-half, and two-thirds the primary resonance frequency. The ability to actuate primary and/or parametric resonances can serve various applications, such as for resonator based logic and memory devices. (C) 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license

  16. Coffee Cup Atomic Force Microscopy

    Science.gov (United States)

    Ashkenaz, David E.; Hall, W. Paige; Haynes, Christy L.; Hicks, Erin M.; McFarland, Adam D.; Sherry, Leif J.; Stuart, Douglas A.; Wheeler, Korin E.; Yonzon, Chanda R.; Zhao, Jing; Godwin, Hilary A.; Van Duyne, Richard P.

    2010-01-01

    In this activity, students use a model created from a coffee cup or cardstock cutout to explore the working principle of an atomic force microscope (AFM). Students manipulate a model of an AFM, using it to examine various objects to retrieve topographic data and then graph and interpret results. The students observe that movement of the AFM…

  17. Microscopic cross sections: An utopia?

    Energy Technology Data Exchange (ETDEWEB)

    Hilaire, S. [CEA Bruyeres-le-Chatel, DIF 91 (France); Koning, A.J. [Nuclear Research and Consultancy Group, PO Box 25, 1755 ZG Petten (Netherlands); Goriely, S. [Institut d' Astronomie et d' Astrophysique, Universite Libre de Bruxelles, Campus de la Plaine, CP 226, 1050 Brussels (Belgium)

    2010-07-01

    The increasing need for cross sections far from the valley of stability poses a challenge for nuclear reaction models. So far, predictions of cross sections have relied on more or less phenomenological approaches, depending on parameters adjusted to available experimental data or deduced from systematical relations. While such predictions are expected to be reliable for nuclei not too far from the experimentally known regions, it is clearly preferable to use more fundamental approaches, based on sound physical bases, when dealing with very exotic nuclei. Thanks to the high computer power available today, all major ingredients required to model a nuclear reaction can now be (and have been) microscopically (or semi-microscopically) determined starting from the information provided by a nucleon-nucleon effective interaction. We have implemented all these microscopic ingredients in the TALYS nuclear reaction code, and we are now almost able to perform fully microscopic cross section calculations. The quality of these ingredients and the impact of using them instead of the usually adopted phenomenological parameters will be discussed. (authors)

  18. Curriculum Guidelines for Microscopic Anatomy.

    Science.gov (United States)

    Journal of Dental Education, 1993

    1993-01-01

    The American Association of Dental Schools' guidelines for curricula in microscopic anatomy offer an overview of the histology curriculum, note primary educational goals, outline specific content for general and oral histology, suggest prerequisites, and make recommendations for sequencing. Appropriate faculty and facilities are also suggested.…

  19. Phase sensitive scanning optical microscope

    Energy Technology Data Exchange (ETDEWEB)

    Jungerman, R.L.; Hobbs, P.C.D.; Kino, G.S.

    1984-10-15

    An electronically scanned optical microscope which quantitatively measures amplitude and phase is described. The system is insenstive to mechanical vibrations. The phase infromation makes it possible to measure surface height variations with an accuracy of better than 100 A and can also be used to improve the lateral resolution.

  20. Nanofabrication of magnetic scanned-probe microscope sensors

    CERN Document Server

    Chong, B K

    2001-01-01

    experiments were carried out under ambient conditions. The experiments required no extra preparation to be done to the specimen before imaging and measurements were carried out under ambient conditions. These probes offer the prospect of direct magnetic field measurement, non- invasiveness, very close proximity, possible local manipulation, better control over the tip- specimen interaction distance and topographic imaging. It is hoped that these magnetic microscope probes will be of great interest and general utility for academic and industrial magneticians. This thesis presents the development of novel magnetic sensor combined with Atomic Force Microscope probe (AFM) using conventional semiconductor processing techniques and Electron Beam Lithography (EBL). The fabrication of these magnetic sensors was performed on a common micromachined silicon substrate using a generic batch fabrication technique. Sub-micron Hall bar for Scanning Hall probe Microscopy (SHPM) and electromagnetic force coil magnet for Scanni...

  1. Microscope sterility during spine surgery.

    Science.gov (United States)

    Bible, Jesse E; O'Neill, Kevin R; Crosby, Colin G; Schoenecker, Jonathan G; McGirt, Matthew J; Devin, Clinton J

    2012-04-01

    Prospective study. Assess the contamination rates of sterile microscope drapes after spine surgery. The use of the operating microscope has become more prevalent in certain spine procedures, providing superior magnification, visualization, and illumination of the operative field. However, it may represent an additional source of bacterial contamination and increase the risk of developing a postoperative infection. This study included 25 surgical spine cases performed by a single spine surgeon that required the use of the operative microscope. Sterile culture swabs were used to obtain samples from 7 defined locations on the microscope drape after its use during the operation. The undraped technician's console was sampled in each case as a positive control, and an additional 25 microscope drapes were swabbed immediately after they were applied to the microscope to obtain negative controls. Swab samples were assessed for bacterial growth on 5% sheep blood Columbia agar plates using a semiquantitative technique. No growth was observed on any of the 25 negative control drapes. In contrast, 100% of preoperative and 96% of postoperative positive controls demonstrated obvious contamination. In the postoperative group, all 7 sites of evaluation were found to be contaminated with rates of 12% to 44%. Four of the 7 evaluated locations were found to have significant contamination rates compared with negative controls, including the shafts of the optic eyepieces on the main surgeon side (24%, P = 0.022), "forehead" portion on both the main surgeon (24%, P = 0.022) and assistant sides (28%, P = 0.010), and "overhead" portion of the drape (44%, P = 0.0002). Bacterial contamination of the operative microscope was found to be significant after spine surgery. Contamination was more common around the optic eyepieces, likely due to inadvertent touching of unsterile portions. Similarly, all regions above the eyepieces also have a propensity for contamination because of unknown contact

  2. Microscopic information processing and communication in crowd dynamics

    Science.gov (United States)

    Henein, Colin Marc; White, Tony

    2010-11-01

    Due, perhaps, to the historical division of crowd dynamics research into psychological and engineering approaches, microscopic crowd models have tended toward modelling simple interchangeable particles with an emphasis on the simulation of physical factors. Despite the fact that people have complex (non-panic) behaviours in crowd disasters, important human factors in crowd dynamics such as information discovery and processing, changing goals and communication have not yet been well integrated at the microscopic level. We use our Microscopic Human Factors methodology to fuse a microscopic simulation of these human factors with a popular microscopic crowd model. By tightly integrating human factors with the existing model we can study the effects on the physical domain (movement, force and crowd safety) when human behaviour (information processing and communication) is introduced. In a large-room egress scenario with ample exits, information discovery and processing yields a crowd of non-interchangeable individuals who, despite close proximity, have different goals due to their different beliefs. This crowd heterogeneity leads to complex inter-particle interactions such as jamming transitions in open space; at high crowd energies, we found a freezing by heating effect (reminiscent of the disaster at Central Lenin Stadium in 1982) in which a barrier formation of naïve individuals trying to reach blocked exits prevented knowledgeable ones from exiting. Communication, when introduced, reduced this barrier formation, increasing both exit rates and crowd safety.

  3. The nature of the gecko lizard adhesive force.

    Science.gov (United States)

    Sun, Wanxin; Neuzil, Pavel; Kustandi, Tanu Suryadi; Oh, Sharon; Samper, Victor D

    2005-08-01

    The extraordinary climbing skills of gecko lizards have been under investigation for a long time. Here we report results of direct measurement of single spatula forces in air with varying relative humidities and in water, by the force-distance method using an atomic force microscope. We have found that the presence of water strongly affects the adhesion force and from analysis of our results, we have demonstrated that the dominant force involved is the capillary force.

  4. The Nature of the Gecko Lizard Adhesive Force

    OpenAIRE

    Sun, Wanxin; Neuzil, Pavel; Kustandi, Tanu Suryadi; Oh, Sharon; Samper, Victor D.

    2005-01-01

    The extraordinary climbing skills of gecko lizards have been under investigation for a long time. Here we report results of direct measurement of single spatula forces in air with varying relative humidities and in water, by the force-distance method using an atomic force microscope. We have found that the presence of water strongly affects the adhesion force and from analysis of our results, we have demonstrated that the dominant force involved is the capillary force.

  5. Combined AFM and confocal fluorescence microscope for applications in bio-nanotechnology

    NARCIS (Netherlands)

    Kassies, R.; van der Werf, Kees; Lenferink, Aufrid T.M.; Hunter, C.N.; Olsen, J.D.; Subramaniam, Vinod; Otto, Cornelis

    2005-01-01

    We present a custom-designed atomic force fluorescence microscope (AFFM), which can perform simultaneous optical and topographic measurements with single molecule sensitivity throughout the whole visible to near-infrared spectral region. Integration of atomic force microscopy (AFM) and confocal

  6. SS-HORSE method for studying resonances

    Energy Technology Data Exchange (ETDEWEB)

    Blokhintsev, L. D. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Mazur, A. I.; Mazur, I. A., E-mail: 008043@pnu.edu.ru [Pacific National University (Russian Federation); Savin, D. A.; Shirokov, A. M. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

    2017-03-15

    A new method for analyzing resonance states based on the Harmonic-Oscillator Representation of Scattering Equations (HORSE) formalism and analytic properties of partial-wave scattering amplitudes is proposed. The method is tested by applying it to the model problem of neutral-particle scattering and can be used to study resonance states on the basis of microscopic calculations performed within various versions of the shell model.

  7. Fabrication of large area plasmonic nanoparticle grating structure on silver halide based transmission electron microscope film and its application as a surface enhanced Raman spectroscopy substrate

    Energy Technology Data Exchange (ETDEWEB)

    Sudheer,, E-mail: sudheer@rrcat.gov.in; Tiwari, P.; Singh, M. N.; Sinha, A. K.; Rai, V. N.; Srivastava, A. K. [Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology Indore, Madhya Pradesh 452013 (India); Bhartiya, S. [Laser Material Development and Device Division, Raja Ramanna Centre for Advanced Technology Indore, Madhya Pradesh 452013 (India); Mukherjee, C. [Mechanical and Optical Support Section, Raja Ramanna Centre for Advanced Technology Indore, Madhya Pradesh 452013 (India)

    2015-08-14

    The plasmonic responses of silver nanoparticle grating structures of different periods made on silver halide based electron microscope film are investigated. Raster scan of the conventional scanning electron microscope (SEM) is used to carry out electron beam lithography for fabricating the plasmonic nanoparticle grating (PNG) structures. Morphological characterization of the PNG structures, carried out by the SEM and the atomic force microscope, indicates that the depth of the groove decreases with a decrease in the grating period. Elemental characterization performed by the energy dispersive spectroscopy and the x-ray diffraction shows the presence of nanoparticles of silver in the PNG grating. The optical characterization of the gratings shows that the localized surface plasmon resonance peak shifts from 366 to 378 nm and broadens with a decrease in grating period from 10 to 2.5 μm. The surface enhanced Raman spectroscopy of the Rhodamine-6G dye coated PNG structure shows the maximum enhancement by two orders of magnitude in comparison to the randomly distributed silver nanoparticles having similar size and shape as the PNG structure.

  8. Photothermal resonance

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a method for detecting photo-thermal absorbance of a material utilising a mechanically temperature sensitive resonator (20) and a sample being arrange in thermal communication with the temperature sensitive resonator. The present invention further relates...

  9. Fast, high-resolution surface potential measurements in air with heterodyne Kelvin probe force microscopy

    Science.gov (United States)

    Garrett, Joseph L.; Munday, Jeremy N.

    2016-06-01

    Kelvin probe force microscopy (KPFM) adapts an atomic force microscope to measure electric potential on surfaces at nanometer length scales. Here we demonstrate that Heterodyne-KPFM enables scan rates of several frames per minute in air, and concurrently maintains spatial resolution and voltage sensitivity comparable to frequency-modulation KPFM, the current spatial resolution standard. Two common classes of topography-coupled artifacts are shown to be avoidable with H-KPFM. A second implementation of H-KPFM is also introduced, in which the voltage signal is amplified by the first cantilever resonance for enhanced sensitivity. The enhanced temporal resolution of H-KPFM can enable the imaging of many dynamic processes, such as such as electrochromic switching, phase transitions, and device degredation (battery, solar, etc), which take place over seconds to minutes and involve changes in electric potential at nanometer lengths.

  10. Compact microscope-based optical tweezers system for molecular manipulation

    Science.gov (United States)

    Sischka, Andy; Eckel, Rainer; Toensing, Katja; Ros, Robert; Anselmetti, Dario

    2003-11-01

    A compact single beam optical tweezers system for force measurements and manipulation of individual double-stranded deoxyribonucleic acid (DNA) molecules was integrated into a commercial inverted optical microscope. A maximal force of 150 pN combined with a force sensitivity of less than 0.5 pN allows measurements of elastic properties of single molecules which complements and overlaps the force regime accessible with atomic force microscopy (AFM). The manipulation and measurement performance of this system was tested with individual λ-DNA molecules and renders new aspects of dynamic forces phenomena with higher precision in contrast to AFM studies. An integrated liquid handling system with a fluid cell allows investigation of the force response of individual DNA molecules in the presence of DNA binding agents. Comparison of YOYO-1-, ethidium bromide intercalated DNA, and distamycin-A complexed DNA revealed accurate and reproducible differences in the force response to an external load. This opens the possibility to use it as a single molecule biosensor to investigate DNA binding agents and even to identify molecular binding mechanisms.

  11. 21 CFR 884.6190 - Assisted reproductive microscopes and microscope accessories.

    Science.gov (United States)

    2010-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction.... Assisted reproduction microscopes and microscope accessories (excluding microscope stage warmers, which are classified under assisted reproduction accessories) are optical instruments used to enlarge images of gametes...

  12. Microscope Project for Undergraduate Laboratories

    CERN Document Server

    Chippendale, Rachel Kemp Alexander; Shumway, Jennifer; Tan, Amanda; Zuraw, Sarah; Ross, Jennifer L

    2016-01-01

    Optics is an important subfield of physics required for instrument design and used in a variety of other disciplines, including materials science, physics, and life sciences such as developmental biology and cell biology. It is important to educate students from a variety of disciplines and backgrounds in the basics of optics in order to train the next generation of interdisciplinary researchers and instrumentalists who will push the boundaries of discovery. In this paper, we present an experimental system developed to teach students in the basics of geometric optics, including ray and wave optics. The students learn these concepts through designing, building, and testing a home-built light microscope made from component parts. We describe the experimental equipment and basic measurements students can perform to learn principles, technique, accuracy, and resolution of measurement. Students find the magnification and test the resolution of the microscope system they build. The system is open and versatile to a...

  13. Microscopic colitis: a therapeutic challenge.

    Science.gov (United States)

    Guslandi, Mario

    2013-06-21

    The treatment of microscopic colitis is mainly based on the use of budesonide, the only drug found effective in controlled clinical trials. After an initial course at a dose of 9 mg daily, however, most patients relapse when the drug is discontinued, hence a maintenance therapy at doses of 6 mg daily or lower is necessary. In order to avoid steroid dependence and drug toxicity different pharmacological agents should be considered as an alternative to indefinite long-term budesonide treatment. Evidence-based guidelines are currently lacking due to the lack of conclusive data concerning the use of either immunosuppressive or anti-tumor necrosis factor agents. For the time being in clinical practice the skilled physician should therefore tailor long term management of microscopic colitis on the single patient.

  14. Duties to Extraterrestrial Microscopic Organisms

    Science.gov (United States)

    Cockell, C. S.

    Formulating a normative axiology for the treatment of extraterrestrial microscopic organisms, should they ever be found, requires an extension of environmental ethics to beyond the Earth. Using an ethical framework for the treatment of terrestrial micro-organisms, this paper elaborates a similar ethic for the treatment of extraterrestrial microscopic organisms. An ethic of `teloempathy' allows for the moral considerability of any organism that has `interests', based on rudimentary qualities of conativism, and therefore allows for an identical treatment of all life, related or not related to life on Earth. Although, according to this ethic, individual extraterrestrial microscopic organisms have a good of their own and even `rights', at this level the ethic can only be theoretical, allowing for the inevitable destruction of many individual organisms during the course of human exploratory missions, similarly to the daily destruction of microbes by humans on Earth. A holistic teloempathy, an operative ethic, not only provides a framework for human exploration, but it also has important implications for planetary protection and proposals to implement planetary-scale atmospheric alterations on other bodies. Even prior to the discovery of extraterrestrial life, or the discovery of a complete absence of such life, this exercise yields important insights into the moral philosophy that guides our treatment of terrestrial micro-organisms.

  15. Neuroaesthetic Resonance

    DEFF Research Database (Denmark)

    Brooks, Anthony Lewis

    2013-01-01

    Neuroaesthetic Resonance emerged from a mature body of patient- centered gesture-control research investigating non-formal rehabilitation via ICT-enhanced-Art to question ‘Aesthetic Resonance’. Motivating participation, ludic engagement, and augmenting physical motion in non-formal (fun) treatment...... the unencumbered motion-to-computer-generated activities - ‘Music Making’, ‘Painting’, ‘Robotic’ and ‘Video Game’ control. A focus of this position paper is to highlight how Aesthetic Resonance, in this context, relates to the growing body of research on Neuroaesthetics to evolve Neuroaesthetic Resonance....

  16. The scanning ion conductance microscope for cellular physiology.

    Science.gov (United States)

    Lab, Max J; Bhargava, Anamika; Wright, Peter T; Gorelik, Julia

    2013-01-01

    The quest for nonoptical imaging methods that can surmount light diffraction limits resulted in the development of scanning probe microscopes. However, most of the existing methods are not quite suitable for studying biological samples. The scanning ion conductance microscope (SICM) bridges the gap between the resolution capabilities of atomic force microscope and scanning electron microscope and functional capabilities of conventional light microscope. A nanopipette mounted on a three-axis piezo-actuator, scans a sample of interest and ion current is measured between the pipette tip and the sample. The feedback control system always keeps a certain distance between the sample and the pipette so the pipette never touches the sample. At the same time pipette movement is recorded and this generates a three-dimensional topographical image of the sample surface. SICM represents an alternative to conventional high-resolution microscopy, especially in imaging topography of live biological samples. In addition, the nanopipette probe provides a host of added modalities, for example using the same pipette and feedback control for efficient approach and seal with the cell membrane for ion channel recording. SICM can be combined in one instrument with optical and fluorescent methods and allows drawing structure-function correlations. It can also be used for precise mechanical force measurements as well as vehicle to apply pressure with precision. This can be done on living cells and tissues for prolonged periods of time without them loosing viability. The SICM is a multifunctional instrument, and it is maturing rapidly and will open even more possibilities in the near future.

  17. Resonance – Journal of Science Education | Indian Academy of ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education. Prasanta K Panigrahi. Articles written in Resonance – Journal of Science Education. Volume 9 Issue 3 March 2004 pp 50-64 General Article. Wavelet Transform - A New Mathematical Microscope · Sachin P Nanavati Prasanta K Panigrahi · More Details Fulltext ...

  18. Resonance – Journal of Science Education | Indian Academy of ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education. S Sriramachari. Articles written in Resonance – Journal of Science Education. Volume 13 Issue 3 March 2008 pp 292-306 Face to Face. Of Mechanisms, Microscopes and Methyl isocyanate · S Sriramachari Sujata Varadarajan · More Details Fulltext PDF ...

  19. Literature survey on microscopic friction modeling

    NARCIS (Netherlands)

    Hol, J.

    2010-01-01

    To better understand contact and friction conditions, experimental and theoretical studies have been performed in order to take microscopic dependencies into account. Friction is developed on microscopic level by adhesion between contacting asperities, the ploughing effect between asperities and the

  20. Distributed microscopic actuation analysis of deformable plate membrane mirrors

    Science.gov (United States)

    Lu, Yifan; Yue, Honghao; Deng, Zongquan; Tzou, Hornsen

    2018-02-01

    To further reduce the areal density of optical mirrors used in space telescopes and other space-borne optical structures, the concept of flexible membrane deformable mirror has been proposed. Because of their high flexibility, poor stiffness and low damping properties, environmental excitations such as orbital maneuver, path changing, and non-uniform heating may induce unexpected vibrations and thus reduce working performance. Therefore, active vibration control is essential for these membrane mirrors. In this paper, two different mirror models, i.e., the plate membrane model and pure membrane model, are studied respectively. In order to investigate the modal vibration characteristics of the mirror, a piezoelectric layer is fully laminated on its non-reflective side to serve as actuators. Dynamic equations of the mirror laminated with piezoelectric actuators are presented first. Then, the actuator induced modal control force is defined. When the actuator area shrinks to infinitesimal, the expressions of microscopic local modal control force and its two components are obtained to predict the spatial microscopic actuation behavior of the mirror. Different membrane pretension forces are also applied to reveal the tension effects on the actuation of the mirror. Analyses indicate that the spatial distribution of modal micro-control forces is exactly the same with the sensing signals distribution of the mirror, which provides crucial guidelines for optimal actuator placement of membrane deformable mirrors.

  1. Design and fabrication of label-free biochip using a guided mode resonance filter with nano grating structures by injection molding process.

    Science.gov (United States)

    Cho, E; Kim, B; Choi, S; Han, J; Jin, J; Han, J; Lim, J; Heo, Y; Kim, S; Sung, G Y; Kang, S

    2011-01-01

    This paper introduces technology to fabricate a guided mode resonance filter biochip using injection molding. Of the various nanofabrication processes that exist, injection molding is the most suitable for the mass production of polymer nanostructures. Fabrication of a nanograting pattern for guided mode resonance filters by injection molding requires a durable metal stamp, because of the high injection temperature and pressure. Careful consideration of the optimized process parameters is also required to achieve uniform sub-wavelength gratings with high fidelity. In this study, a metallic nanostructure pattern to be used as the stamp for the injection molding process was fabricated using electron beam lithography, a UV nanoimprinting process, and an electroforming process. A one-dimensional nanograting substrate was replicated by injection molding, during which the process parameters were controlled. To evaluate the geometric quality of the injection molded nanograting patterns, the surface profile of the fabricated nanograting for different processing conditions was analyzed using an atomic force microscope and a scanning electron microscope. Finally, to demonstrate the feasibility of the proposed process for fabricating guided mode resonance filter biochips, a high-refractive-index material was deposited on the polymer nanograting and its guided mode resonance characteristics were analyzed.

  2. Periodic motions and resonances of impact oscillators

    Science.gov (United States)

    Dyskin, Arcady V.; Pasternak, Elena; Pelinovsky, Efim

    2012-06-01

    Bilinear oscillators - the oscillators whose springs have different stiffnesses in compression and tension - model a wide range of phenomena. A limiting case of bilinear oscillator with infinite stiffness in compression - the impact oscillator - is studied here. We investigate a special set of impact times - the eigenset, which corresponds to the solution of the homogeneous equation, i.e. the oscillator without the driving force. We found that this set and its subsets are stable with respect to variation of initial conditions. Furthermore, amongst all periodic sets of impact times with the period commensurate with the period of driving force, the eigenset is the only one which can support resonances, in particular the multi-'harmonic' resonances. Other resonances should produce non-periodic sets of impact times. This funding indicates that the usual simplifying assumption [e.g., S.W. Shaw, P.J. Holmes, A periodically forced piecewise linear oscillator, Journal of Sound and Vibration 90 (1983) 129-155] that the times between impacts are commensurate with the period of the driving force does not always hold. We showed that for the first sub-'harmonic resonance' - the resonance achieved on a half frequency of the main resonance - the set of impact times is asymptotically close to the eigenset. The envelope of the oscillations in this resonance increases as a square root of time, opposite to the linear increase characteristic of multi-'harmonic' resonances.

  3. Microscopically Based Nuclear Energy Functionals

    Science.gov (United States)

    Bogner, S. K.

    2009-05-01

    A major goal of the SciDAC project "Building a Universal Nuclear Energy Density Functional" is to develop next-generation nuclear energy density functionals that give controlled extrapolations away from stability with improved performance across the mass table. One strategy is to identify missing physics in phenomenological Skyrme functionals based on our understanding of the underlying internucleon interactions and microscopic many-body theory. In this contribution, I describe ongoing efforts to use the density matrix expansion of Negele and Vautherin to incorporate missing finite-range effects from the underlying two- and three-nucleon interactions into phenomenological Skyrme functionals.

  4. R-ES-ON--ANCE

    Indian Academy of Sciences (India)

    More commonly, the word is associated with music. (resonance of a piano or organ) and in a figurative sense with positive qualities. These are evident in the following powerful phrases: 'For the beaute, for the force and for the resonaunce' (Ordinary Crysten. Men, 1502) and in the pious wish: "So ought our hearts ... to have ...

  5. Labor Force

    Science.gov (United States)

    Occupational Outlook Quarterly, 2012

    2012-01-01

    The labor force is the number of people ages 16 or older who are either working or looking for work. It does not include active-duty military personnel or the institutionalized population, such as prison inmates. Determining the size of the labor force is a way of determining how big the economy can get. The size of the labor force depends on two…

  6. Optical microscope and tapered fiber coupling apparatus for a dilution refrigerator.

    Science.gov (United States)

    MacDonald, A J R; Popowich, G G; Hauer, B D; Kim, P H; Fredrick, A; Rojas, X; Doolin, P; Davis, J P

    2015-01-01

    We have developed a system for tapered fiber measurements of optomechanical resonators inside a dilution refrigerator, which is compatible with both on- and off-chip devices. Our apparatus features full three-dimensional control of the taper-resonator coupling conditions enabling critical coupling, with an overall fiber transmission efficiency of up to 70%. Notably, our design incorporates an optical microscope system consisting of a coherent bundle of 37,000 optical fibers for real-time imaging of the experiment at a resolution of ∼1 μm. We present cryogenic optical and optomechanical measurements of resonators coupled to tapered fibers at temperatures as low as 9 mK.

  7. Robotic autopositioning of the operating microscope.

    Science.gov (United States)

    Oppenlander, Mark E; Chowdhry, Shakeel A; Merkl, Brandon; Hattendorf, Guido M; Nakaji, Peter; Spetzler, Robert F

    2014-06-01

    Use of the operating microscope has become pervasive since its introduction to the neurosurgical world. Neuronavigation fused with the operating microscope has allowed accurate correlation of the focal point of the microscope and its location on the downloaded imaging study. However, the robotic ability of the Pentero microscope has not been utilized to orient the angle of the microscope or to change its focal length to hone in on a predefined target. To report a novel technology that allows automatic positioning of the operating microscope onto a set target and utilization of a planned trajectory, either determined with the StealthStation S7 by using preoperative imaging or intraoperatively with the microscope. By utilizing the current motorized capabilities of the Zeiss OPMI Pentero microscope, a robotic autopositioning feature was developed in collaboration with Surgical Technologies, Medtronic, Inc. (StealthStation S7). The system is currently being tested at the Barrow Neurological Institute. Three options were developed for automatically positioning the microscope: AutoLock Current Point, Align Parallel to Plan, and Point to Plan Target. These options allow the microscope to pivot around the lesion, hover in a set plane parallel to the determined trajectory, or rotate and point to a set target point, respectively. Integration of automatic microscope positioning into the operative workflow has potential to increase operative efficacy and safety. This technology is best suited for precise trajectories and entry points into deep-seated lesions.

  8. Study on the Microscopic Figures of Power Transformer Insulation Paper Under Electrical and Thermal Stresses

    Science.gov (United States)

    Liao, Rui-Jin; Tang, Chao; Yang, Li-Jun

    In this paper, Atomic Force Microscope (AFM) was used to observe the microscopic figure of aged insulation paper in order to analyze the microscopic ageing mechanism of power transformer insulation paper under electrical and thermal stresses. The results indicate that there are obvious concaves and convexes on the surface of aged insulation paper, and the paper samples are punctured because of chain scission and the flow of discharge current, which destroyed the compact cellulose chains structures and the diameter of punctures is about 0.5 nm. In addition, this paper analyzed the influence to the physical chemistry characteristics of insulation paper caused by partial discharge and paper ageing.

  9. Microscopic colitis: A literature review

    Directory of Open Access Journals (Sweden)

    ANA PAULA HAMER SOUSA CLARA

    Full Text Available SUMMARY Microscopic colitis (MC refers to chronic inflammation of the colon which is characterized by histologic changes at the level of a radiologically and endoscopically normal mucosa. It is a common cause of chronic non-bloody diarrhea that occurs primarily in older individuals; however, there are few studies in the literature with strong scientific evidence compared to other inflammatory bowel diseases (IBD, which limits the knowledge of physicians and pathologists. This article aims to review the information on MC, describing diagnostic methods and drugs available for treatment. We conducted a search of the Pubmed database and CAPES Portal using the keywords “microscopic colitis”, “collagenous colitis”, “lymphocytic colitis”, and “review” for selection of articles published between 1996 and 2015 related to the topic. Based on the studies discussed in this review, we conclude that MC is a relatively new gastrointestinal disorder, most studies are incipient particularly with respect to pathophysiology and immunology, and budesonide is the best documented short-term treatment. However, further studies are needed to elucidate the best strategy for treatment in the long term.

  10. Microscopic colitis: A literature review.

    Science.gov (United States)

    Clara, Ana Paula Hamer Sousa; Magnago, Flávia Drago; Ferreira, Juliana Neves; Grillo, Thais Gagno

    2016-12-01

    Microscopic colitis (MC) refers to chronic inflammation of the colon which is characterized by histologic changes at the level of a radiologically and endoscopically normal mucosa. It is a common cause of chronic non-bloody diarrhea that occurs primarily in older individuals; however, there are few studies in the literature with strong scientific evidence compared to other inflammatory bowel diseases (IBD), which limits the knowledge of physicians and pathologists. This article aims to review the information on MC, describing diagnostic methods and drugs available for treatment. We conducted a search of the Pubmed database and CAPES Portal using the keywords "microscopic colitis", "collagenous colitis", "lymphocytic colitis", and "review" for selection of articles published between 1996 and 2015 related to the topic. Based on the studies discussed in this review, we conclude that MC is a relatively new gastrointestinal disorder, most studies are incipient particularly with respect to pathophysiology and immunology, and budesonide is the best documented short-term treatment. However, further studies are needed to elucidate the best strategy for treatment in the long term.

  11. Force sensitivity of multilayer graphene optomechanical devices.

    Science.gov (United States)

    Weber, P; Güttinger, J; Noury, A; Vergara-Cruz, J; Bachtold, A

    2016-08-09

    Mechanical resonators based on low-dimensional materials are promising for force and mass sensing experiments. The force sensitivity in these ultra-light resonators is often limited by the imprecision in the measurement of the vibrations, the fluctuations of the mechanical resonant frequency and the heating induced by the measurement. Here, we strongly couple multilayer graphene resonators to superconducting cavities in order to achieve a displacement sensitivity of 1.3 fm Hz(-1/2). This coupling also allows us to damp the resonator to an average phonon occupation of 7.2. Our best force sensitivity, 390 zN Hz(-1/2) with a bandwidth of 200 Hz, is achieved by balancing measurement imprecision, optomechanical damping, and measurement-induced heating. Our results hold promise for studying the quantum capacitance of graphene, its magnetization, and the electron and nuclear spins of molecules adsorbed on its surface.

  12. Separate-type scanner and wideband high-voltage amplifier for atomic-resolution and high-speed atomic force microscopy

    OpenAIRE

    Miyata, Kazuki; Usho, Satoshi; Yamada, Satoshi; Furuya, Shoji; Yoshida, Kiyonori; Asakawa, Hitoshi; Fukuma, Takeshi

    2013-01-01

    We have developed a liquid-environment atomic force microscope with a wideband and low-noise scanning system for atomic-scale imaging of dynamic processes at solid/liquid interfaces. The developed scanning system consists of a separate-type scanner and a wideband high-voltage amplifier (HVA). By separating an XY-sample scanner from a Z-tip scanner, we have enabled to use a relatively large sample without compromising the high resonance frequency. We compared various cantilever- and sample-hol...

  13. Microscopic theory of nuclear fission: a review

    Science.gov (United States)

    Schunck, N.; Robledo, L. M.

    2016-11-01

    This article reviews how nuclear fission is described within nuclear density functional theory. A distinction should be made between spontaneous fission, where half-lives are the main observables and quantum tunnelling the essential concept, and induced fission, where the focus is on fragment properties and explicitly time-dependent approaches are often invoked. Overall, the cornerstone of the density functional theory approach to fission is the energy density functional formalism. The basic tenets of this method, including some well-known tools such as the Hartree-Fock-Bogoliubov (HFB) theory, effective two-body nuclear potentials such as the Skyrme and Gogny force, finite-temperature extensions and beyond mean-field corrections, are presented succinctly. The energy density functional approach is often combined with the hypothesis that the time-scale of the large amplitude collective motion driving the system to fission is slow compared to typical time-scales of nucleons inside the nucleus. In practice, this hypothesis of adiabaticity is implemented by introducing (a few) collective variables and mapping out the many-body Schrödinger equation into a collective Schrödinger-like equation for the nuclear wave-packet. The region of the collective space where the system transitions from one nucleus to two (or more) fragments defines what are called the scission configurations. The inertia tensor that enters the kinetic energy term of the collective Schrödinger-like equation is one of the most essential ingredients of the theory, since it includes the response of the system to small changes in the collective variables. For this reason, the two main approximations used to compute this inertia tensor, the adiabatic time-dependent HFB and the generator coordinate method, are presented in detail, both in their general formulation and in their most common approximations. The collective inertia tensor enters also the Wentzel-Kramers-Brillouin (WKB) formula used to extract

  14. Imaging the Microscopic Structure of Shear Thinning and Thickening Colloidal Suspensions

    KAUST Repository

    Cheng, X.

    2011-09-01

    The viscosity of colloidal suspensions varies with shear rate, an important effect encountered in many natural and industrial processes. Although this non-Newtonian behavior is believed to arise from the arrangement of suspended particles and their mutual interactions, microscopic particle dynamics are difficult to measure. By combining fast confocal microscopy with simultaneous force measurements, we systematically investigate a suspension\\'s structure as it transitions through regimes of different flow signatures. Our measurements of the microscopic single-particle dynamics show that shear thinning results from the decreased relative contribution of entropic forces and that shear thickening arises from particle clustering induced by hydrodynamic lubrication forces. This combination of techniques illustrates an approach that complements current methods for determining the microscopic origins of non-Newtonian flow behavior in complex fluids.

  15. Multiquark Resonances

    CERN Document Server

    Esposito, A.; Polosa, A.D.

    2016-01-01

    Multiquark resonances are undoubtedly experimentally observed. The number of states and the amount of details on their properties has been growing over the years. It is very recent the discovery of two pentaquarks and the confirmation of four tetraquarks, two of which had not been observed before. We mainly review the theoretical understanding of this sector of particle physics phenomenology and present some considerations attempting a coherent description of the so called X and Z resonances. The prominent problems plaguing theoretical models, like the absence of selection rules limiting the number of states predicted, motivate new directions in model building. Data are reviewed going through all of the observed resonances with particular attention to their common features and the purpose of providing a starting point to further research.

  16. 996 RESONANCE November 2013

    Indian Academy of Sciences (India)

    IAS Admin

    996. RESONANCE. November 2013. Page 2. 997. RESONANCE. November 2013. Page 3. 998. RESONANCE. November 2013. Page 4. 999. RESONANCE. November 2013. Page 5. 1000. RESONANCE. November 2013. Page 6. 1001. RESONANCE. November 2013. Page 7. 1002. RESONANCE. November 2013 ...

  17. 817 RESONANCE September 2013

    Indian Academy of Sciences (India)

    IAS Admin

    817. RESONANCE ⎜ September 2013. Page 2. 818. RESONANCE ⎜ September 2013. Page 3. 819. RESONANCE ⎜ September 2013. Page 4. 820. RESONANCE ⎜ September 2013. Page 5. 821. RESONANCE ⎜ September 2013. Page 6. 822. RESONANCE ⎜ September 2013. Page 7. 823. RESONANCE ⎜ September ...

  18. 369 RESONANCE April 2016

    Indian Academy of Sciences (India)

    IAS Admin

    369. RESONANCE ⎜ April 2016. Page 2. 370. RESONANCE ⎜ April 2016. Page 3. 371. RESONANCE ⎜ April 2016. Page 4. 372. RESONANCE ⎜ April 2016. Page 5. 373. RESONANCE ⎜ April 2016. Page 6. 374. RESONANCE ⎜ April 2016. Page 7. 375. RESONANCE ⎜ April 2016.

  19. Microscopic dynamics of liquid hydrogen

    CERN Document Server

    Zoppi, M; Celli, M

    2001-01-01

    We have measured the almost-pure incoherent scattering function of liquid parahydrogen using neutron inelastic scattering. The experiment was carried out on TOSCA, a time-of-flight, inverse geometry, crystal analyser spectrometer, operating on the pulsed- neutron source ISIS (UK). Since the instrument kinematic region is close to a line in the (k, E)-plane, we have actually measured the projection of S/sub inc/(k, w) on this line. The measured cross- section gives a direct experimental access to the microscopic dynamic of the centre-of-mass motion of molecular hydrogen. The data have been analysed using the Gaussian approximation and have been compared with the results of a novel Quantum Mechanical Molecular Dynamics simulation technique. The results are encouraging, but claim for further developments of the theoretical approach, as well as for more extensive experimental data. (14 refs).

  20. Microscopic dynamics underlying anomalous diffusion

    Science.gov (United States)

    Kaniadakis, G.; Lapenta, G.

    2000-09-01

    The time-dependent Tsallis statistical distribution describing anomalous diffusion is usually obtained in the literature as the solution of a nonlinear Fokker-Planck (FP) equation [A.R. Plastino and A. Plastino, Physica A 222, 347 (1995)]. The scope of the present paper is twofold. First, we show that this distribution can be obtained also as a solution of the nonlinear porous media equation. Second, we prove that the time-dependent Tsallis distribution can be obtained also as a solution of a linear FP equation [G. Kaniadakis and P. Quarati, Physica A 237, 229 (1997)] with coefficients depending on the velocity, which describes a generalized Brownian motion. This linear FP equation is shown to arise from a microscopic dynamics governed by a standard Langevin equation in the presence of multiplicative noise.